WorldWideScience

Sample records for calor por absorcion

  1. 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.

  2. 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)

    1997-12-31

    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.

  3. Industrial refrigeration with high efficiency absorption; Refrigeracion industrial por absorcion de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Ayala Delgado, R.; Heard, C. L. [Instituto de Investigaciones Electricas, Cuernavaca, (Mexico); Pardubicki, J. [LAJ International, Mexico D. F. (Mexico)

    1995-12-31

    The absorption refrigeration ammonia-lithium nitrate offers great advantages compared with the mechanical compression refrigeration with ammonia as well as with the absorption ammonia-water refrigeration. With heat temperatures of 1000 to 1400 Celsius degrees, for instance low pressure steam the generation of cold at low temperatures (-100 to -200 Celsius degrees) is possible. The system has less components and is much less expensive than the ammonia-water equipment with a price very similar to the ammonia mechanical compression equipment. The equipment consists of five main heat exchangers and a solution pump, resulting in a high reliability of its operation, requiring a minimum maintenance. The operation cost depends directly of the cost of the energy source. In case of using residual heat the operation cost is only the maintenance cost. Nowadays the cost of the electric energy is below the production cost, which can be a short term situation. In time terms of the comparable useful life time of an absorption refrigeration system (in excess of 20 years), it is reasonable to think that the operation costs will be less than the operation costs of an equipment with mechanical compression. To this day it is available a demonstration unit to exhibit the system in industrial plants with different energy sources. [Espanol] La refrigeracion por absorcion amoniaco/nitrato de litio ofrece grandes ventajas comparada tanto con la refrigeracion por compresion mecanica con amoniaco como con la refrigeracion por absorcion amoniaco/agua. Este sistema es mas eficiente y sencillo que el sistema de amoniaco/agua. Con calor de temperatura (100 a 140 grados centigrados por ejemplo vapor de baja presion, se permite la generacion de frio a temperaturas bajas (-10 a -20 grados centigrados). El sistema tiene menos componentes y es mucho mas barato que equipo de amoniaco/agua con un precio muy similar a sistemas por compresion mecanica de amoniaco. El sistema consiste en cinco

  4. Industrial refrigeration with high efficiency absorption; Refrigeracion industrial por absorcion de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Ayala Delgado, R; Heard, C L [Instituto de Investigaciones Electricas, Cuernavaca, (Mexico); Pardubicki, J [LAJ International, Mexico D. F. (Mexico)

    1996-12-31

    The absorption refrigeration ammonia-lithium nitrate offers great advantages compared with the mechanical compression refrigeration with ammonia as well as with the absorption ammonia-water refrigeration. With heat temperatures of 1000 to 1400 Celsius degrees, for instance low pressure steam the generation of cold at low temperatures (-100 to -200 Celsius degrees) is possible. The system has less components and is much less expensive than the ammonia-water equipment with a price very similar to the ammonia mechanical compression equipment. The equipment consists of five main heat exchangers and a solution pump, resulting in a high reliability of its operation, requiring a minimum maintenance. The operation cost depends directly of the cost of the energy source. In case of using residual heat the operation cost is only the maintenance cost. Nowadays the cost of the electric energy is below the production cost, which can be a short term situation. In time terms of the comparable useful life time of an absorption refrigeration system (in excess of 20 years), it is reasonable to think that the operation costs will be less than the operation costs of an equipment with mechanical compression. To this day it is available a demonstration unit to exhibit the system in industrial plants with different energy sources. [Espanol] La refrigeracion por absorcion amoniaco/nitrato de litio ofrece grandes ventajas comparada tanto con la refrigeracion por compresion mecanica con amoniaco como con la refrigeracion por absorcion amoniaco/agua. Este sistema es mas eficiente y sencillo que el sistema de amoniaco/agua. Con calor de temperatura (100 a 140 grados centigrados por ejemplo vapor de baja presion, se permite la generacion de frio a temperaturas bajas (-10 a -20 grados centigrados). El sistema tiene menos componentes y es mucho mas barato que equipo de amoniaco/agua con un precio muy similar a sistemas por compresion mecanica de amoniaco. El sistema consiste en cinco

  5. Industrial refrigeration by absorption/compression; Refrigeracion industrial por absorcion/compresion

    Energy Technology Data Exchange (ETDEWEB)

    Ayala Delgado, Ramon; Heard, Christopher Lionel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The use of the absorption/compression refrigeration in the industrial area is analyzed. It is estimated than in Mexico 50% of the food is wasted for lack of refrigeration in the producing centers and by the inefficient distribution system, as well as for the hot climate. The functioning of the absorption refrigeration and the hybrid system absorption/compression which can operate with the two thermodynamic cycles in variable proportions, depending on the specific application, looking for operational advantages and energy efficiency is described. This type of technology could be applied in Mexico due to the lack of industrial refrigeration and to the need of substituting compressors in some companies which have up to 20 years of use [Espanol] Se analiza el uso de la refrigeracion por absorcion/compresion en el area industrial. En Mexico se estima que se desperdicia el 50% de los alimentos por falta de refrigeracion en los centros productores y por el deficiente sistema de distribucion, asi como por el clima calido. Se describe el funcionamiento de la refrigeracion por absorcion y la refrigeracion por absorcion/compresion o sistema hibrido, el cual puede funcionar con los dos tipos de ciclos termodinamicos, en proporciones variables, dependiendo de la aplicacion especifica, buscando ventajas de operacion y eficiencia energetica. Este tipo de tecnologia podria aplicarse en Mexico debido a la falta de refrigeracion industrial y a la necesidad de sustituir compresores en algunas empresas los cuales tienen hasta 20 anos de uso

  6. Industrial refrigeration by absorption/compression; Refrigeracion industrial por absorcion/compresion

    Energy Technology Data Exchange (ETDEWEB)

    Ayala Delgado, Ramon; Heard, Christopher Lionel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The use of the absorption/compression refrigeration in the industrial area is analyzed. It is estimated than in Mexico 50% of the food is wasted for lack of refrigeration in the producing centers and by the inefficient distribution system, as well as for the hot climate. The functioning of the absorption refrigeration and the hybrid system absorption/compression which can operate with the two thermodynamic cycles in variable proportions, depending on the specific application, looking for operational advantages and energy efficiency is described. This type of technology could be applied in Mexico due to the lack of industrial refrigeration and to the need of substituting compressors in some companies which have up to 20 years of use [Espanol] Se analiza el uso de la refrigeracion por absorcion/compresion en el area industrial. En Mexico se estima que se desperdicia el 50% de los alimentos por falta de refrigeracion en los centros productores y por el deficiente sistema de distribucion, asi como por el clima calido. Se describe el funcionamiento de la refrigeracion por absorcion y la refrigeracion por absorcion/compresion o sistema hibrido, el cual puede funcionar con los dos tipos de ciclos termodinamicos, en proporciones variables, dependiendo de la aplicacion especifica, buscando ventajas de operacion y eficiencia energetica. Este tipo de tecnologia podria aplicarse en Mexico debido a la falta de refrigeracion industrial y a la necesidad de sustituir compresores en algunas empresas los cuales tienen hasta 20 anos de uso

  7. Conservación por calor

    OpenAIRE

    Cobos García, Angel; Díaz Rubio, Olga

    2011-01-01

    Esta unidade didáctica denominada Conservación por calor forma parte da materia «Tecnoloxía do procesado de alimentos» que se impartirá no primeiro semestre do 2º curso do Grao en Nutrición Humana e Dietética. A materia estrutúrase en diferentes unidades didácticas, tratando cada unha delas as diferentes tecnoloxías de procesado dos alimentos, tanto de conservación coma de transformación. A presente unidade didáctica aborda a conservación dos alimentos por calor. Este método permite destruír ...

  8. The use of absorption refrigeration systems in combined cycle power plants; Empleo de sistemas de refrigeracion por absorcion en plantas de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H.; Ambriz, J.J.; Vargas, M.; Godinez, M.; Gomez, F.; Valdez, L.; Pantoja, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Departamento de Ingenieria de Procesos e Hidraulica, Mexico D. F. (Mexico)

    1995-12-31

    Day after day the electric power generation tends to be done in the most efficient way in order to diminish the generation costs and the rate of environmental pollution per KWh generated. This paper discusses the application of absorption refrigeration systems for the cooling of the air entering the compressor of a gas turbine in a combined cycle, in order to increase the mass air flow and with it the turbine output. The flows with remanent energy content that are not used in a combined cycle can be used for the operation of the absorption refrigeration system. This way, the required thermal energy for the cooling system is free. With this system it is possible to raise the gas turbine generation output from 5% to 25%. [Espanol] La generacion electrica dia con dia pretende realizarse de la manera mas eficiente posible con el objeto de disminuir los costos de generacion y la tasa de contaminacion ambiental por Kwh generado. En el presente trabajo se introduce la aplicacion de sistemas de refrigeracion por absorcion para el enfriamiento del aire de entrada al compresor de la turbina de gas de un ciclo combinado, con el objeto de aumentar el flujo masico del aire y con ello la potencia de salida de la turbina. Las corrientes con contenido remanente de energia termica que no se usan en una planta de ciclo combinado pueden servir para operar el sistema de refrigeracion por absorcion. De esta manera, la energia termica requerida para el sistema de enfriamiento es gratuita. Con este sistema es posible incrementar la potencia de generacion de la turbina de gas de 5 a 25%.

  9. The use of absorption refrigeration systems in combined cycle power plants; Empleo de sistemas de refrigeracion por absorcion en plantas de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H; Ambriz, J J; Vargas, M; Godinez, M; Gomez, F; Valdez, L; Pantoja, G [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Departamento de Ingenieria de Procesos e Hidraulica, Mexico D. F. (Mexico)

    1996-12-31

    Day after day the electric power generation tends to be done in the most efficient way in order to diminish the generation costs and the rate of environmental pollution per KWh generated. This paper discusses the application of absorption refrigeration systems for the cooling of the air entering the compressor of a gas turbine in a combined cycle, in order to increase the mass air flow and with it the turbine output. The flows with remanent energy content that are not used in a combined cycle can be used for the operation of the absorption refrigeration system. This way, the required thermal energy for the cooling system is free. With this system it is possible to raise the gas turbine generation output from 5% to 25%. [Espanol] La generacion electrica dia con dia pretende realizarse de la manera mas eficiente posible con el objeto de disminuir los costos de generacion y la tasa de contaminacion ambiental por Kwh generado. En el presente trabajo se introduce la aplicacion de sistemas de refrigeracion por absorcion para el enfriamiento del aire de entrada al compresor de la turbina de gas de un ciclo combinado, con el objeto de aumentar el flujo masico del aire y con ello la potencia de salida de la turbina. Las corrientes con contenido remanente de energia termica que no se usan en una planta de ciclo combinado pueden servir para operar el sistema de refrigeracion por absorcion. De esta manera, la energia termica requerida para el sistema de enfriamiento es gratuita. Con este sistema es posible incrementar la potencia de generacion de la turbina de gas de 5 a 25%.

  10. 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,

  11. Resonance absorption of nuclear gamma radiation; Absorption par resonance des rayons gamma; Rezonansnaya absorbtsiya i rasseyanie yadernogo gamma-izlucheniya; Absorcion por resonancia de las radiaciones gamma en los nucleos

    Energy Technology Data Exchange (ETDEWEB)

    Hanna, S S; Perlow, G J [Argonne National Laboratory, Argonne, IL (United States)

    1962-01-15

    electromagnetiques. L'absorption par resonance dans le {sup 57}Fe a ete etudiee en detail. L'intensite de l'absorption, la configuration des raies spectrales et leurs deplacements ont ete observes en fonction de la temperature. La polarisation des rayonnements a ete examinee au cours d'experiences effectuees a l'aide de sources et absorbeurs magnetises. Le spectre hyperfin des rayonnements de resonance a ete analyse avec et sans polarisation. Ces etudes ont conduit a une interpretation de la structure hyperfine en fonction des proprietes des etats nucleaires et de l'interaction hyperfine dans le fer. On a egalement etudie l'effet d'un champ magnetique externe sur la structure hyperfine. L'absorption par resonance dans le {sup 57}Fe a permis d'etudier le rapport entre la chronologie de la desintegration d'un etat nucleaire et le spectre des rayonnements observes. Des observations detaillees ont ete faites sur le spectre des rayonnements de resonance filtres, en fonction du temps, sous toute une serie de conditions. (author) [Spanish] Como ha demostrado Moesbauer, la emision y absorcion sin retrocesos de las radiaciones nucleares proporciona un medio sencillo de estudiar la interaccion entre los nucleos y las radiaciones electromagneticas y, lo que tiene mas importancia aun, un instrumento extremadamente sensible para la investigacion de numerosos problemas fisicos. El nucleo del {sup 57}Fe constituye un ejemplo muy interesante, ya que en el la absorcion por resonancia constituye un detector de gran sensibilidad de los cambios de frecuencia de las radiaciones electromagneticas. Los autores han estudiado detalladamente la absorcion por resonancia en el {sup 57}Fe. Han observado la intensidad de la absorcion, asi como la configuracion y el desplazamiento de las lineas espectrales en funcion de la temperatura. Examinaron la polarizacion de las radiaciones mediante experimentos realizados con ayuda de fuentes magnetizadas y de absorbentes, y analizaron el espectro hiperfino de la

  12. 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

  13. 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

  14. Treatment of radiostrontium uptake in man; Traitement de la fixation de radiostrontium chez l'homme; Lechenie posledstvij pogloshcheniya radioaktivnogo strontsiya u cheloveka; Tratamiento de la radiotoxemla humana causada por absorcion de radioestroncio

    Energy Technology Data Exchange (ETDEWEB)

    Volf, V. [Department of Ionizing Radiation Institute of Industrial Hygiene and Occupational Disease, Prague, CSSR (Czech Republic)

    1963-02-15

    'autres possibilites de traitement de premiere urgence de la contamination interne aigue par le radiostrontium chez l'homme. (author) [Spanish] En experimentos de corta duracion realizados con ratas, se ha modificado la absorcion del radioestroncio a traves de la pared intestinal por tratamiento oral con sulfato barico y fosfato calcico normal. Por el contrario, ha permanecido inalterada la absorcion del ''9''0Sr administrado con el agua de bebida a ratas sometidas a un regimen que comprendia sulfato barico. De ello se deduce que esta sustancia solo puede ser de alguna utilidad en un tratamiento de primeros auxilios. En dos casos de ligera contaminacion interna consecutiva a la inhalacion accidental de nitrato de {sup 90}Sr se ha administrado suliato barico (Skiabaryum Spoia) por via oral a los 10 y 30 minutos de ocurrir la inhalacion. La eficacia de este tratamiento se ha verificado en experimentos realizados con ratas en las mismas condiciones en que se produjeron los accidentes. En fecha mas reciente, se han efectuado experimentos analogos en varios enfermos de cancer para estudiar otras posibilidades que ofrece el tratamiento de primeros auxilios, administrado a raiz de una contaminacion interna aguda causada por el radioestroncio en el organismo humano. (author) [Russian] V neprodolzhitel'nykh ehksperimentakh na krysakh izuchalos' izmenenie prokhozhdeniya radiostrontsiya cherez kishechnuyu stenku pod vliyaniem skarmlivaniya sernokislogo bariya i normal'nogo fosfornokislogo kal'tsiya. Odnako u krys, soderzhashchikhsya na diete, vklyuchayushchej sernokislyj barij, ne obnaruzheno izmenenij vsasyvaniya strontsiya-90, kotoryj zhivotnye poluchali s pit'evoj vodoj. Sdelan vyvod, chto ehto veshchestvo mozhet primenyat'sya lish' dlya okazaniya pervoj pomoshchi. V dvukh sluchayakh legkogo vnutrennego zarazheniya posle sluchajnogo vdykhaniya nitrata strontsiya-90 sernokislyj barij (Skiabarij Spofa) davalsya vnutr' cherez 10 i 30 minut posle vdykhaniya strontsiya-90. Ehivnoot' ehtogo

  15. DISEÑO Y CONSTRUCCIÓN DE PROTOTIPO PARA MEDICIÓN DE FLUJO DE CALOR APLICANDO CALORIMETRÍA DIRECTA: SENSADO POR FLUJO DE CALOR

    Directory of Open Access Journals (Sweden)

    OSCAR CADENA

    2008-01-01

    Full Text Available El presente artículo describe el diseño de un prototipo inalámbrico para la medición de flujo de calor, que permita a futuro aplicar el método de calorimetría directa por gradiente de flujo de calor en el área de la electrónica médica. Esta técnica se desarrolla gracias al avance y creación de sensores que permiten medir este tipo de variables, y se postula como una alternativa a las formas de medición utilizadas actualmente, presentando mejoras en su desempeño y costo. Los resultados obtenidos luego de efectuar la calibración del equipo permiten inferir que la técnica propuesta se adapta de forma eficiente y puede utilizarse como un sustituto significativamente más ventajoso comparado con los métodos existentes en la actualidad y aplicados en el seguimiento metabólico de personas.

  16. Hydrogen absorption in Mg1.95Ti0.05Ni0.95Cu0.05 alloy prepared with mechanical alloying and thermal treatment; Absorcion de hidrogeno en la aleacion Mg1.95Ti0.05Ni0.95Cu0.05 preparada por aleado mecanico y tratamiento termico

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Juan Bonifacio; Urena Nunez, Fernando [Instituto Nacional de Investigaciones Nucleares, Ocoyoacac, Estado de Mexico (Mexico)]. E-mail: juan.bonifacio@inin.gob.mx

    2009-09-15

    This work presents hydrogen absorption in quaternary alloy Mg1.95Ti0.05Ni0.95Cu0.05 obtained by the mechanical alloying method, followed by thermal treatment in ultra-high pure argon atmosphere. The composition of the phases, microstructure and morphology of ground powders and with thermal treatment were characterized by DRX, SEM/EDS and TEM. After 20 hours of mechanical grinding and recooked at 300 degrees Celsius/1h in argon atmosphere, the quaternary alloy has a Mg{sub 2}Ni crystalline hexagonal structure with a crystallite size under 10 nm. The absorption measurements were performed under a pressure of 0.2 to 1.2 MPa at a temperature of 200 degrees Celsius in a micro-reactor. The quantification of absorption-desorption of hydrogen in the intermetallic was conducted in a TGA-DSC simultaneous calorimeter. Metallic hydride-dehydride powder was characterized with SEM and XRD. [Spanish] En este trabajo se presenta la absorcion de hidrogeno en la aleacion cuaternaria Mg1.95Ti0.05Ni0.95Cu0.05 obtenida por el metodo de aleado mecanico, seguida de tratamiento termico en atmosfera de argon de ultra alta pureza. La composicion de las fases, microestructura y morfologia de los polvos molidos y con tratamiento termico fue caracterizada por DRX, SEM/EDS y TEM. Despues de 20 h de molienda mecanica con recocido a 300 grados Celsios/1h en atmosfera de argon, la aleacion cuaternaria tiene una estructura cristalina hexagonal Mg{sub 2}Ni con tamano de cristalito menor a 10 nm. Las mediciones de absorcion fueron realizadas bajo una presion de 0.2 a 1.2 MPa a una temperatura de 200 grados Celsios en un micro-reactor. La cuantificacion de absorcion-desorcion de hidrogeno en el intermetalico se realizo en un calorimetro simultaneo TGA-DSC. Se determino que la cantidad maxima absorbida de hidrogeno en la aleacion cuaternaria fue de 3.24% en peso cuando la presion fue de 0.8 MPa a dicha temperatura. Polvos metalicos hidrurados-deshidrurados se caracterizaron por SEM y XRD.

  17. Atenuación del estrés por calor en vacuno lechero: nebulización

    OpenAIRE

    Mena Guerrero, Y.; Serradilla Manrique, J.M.; Gómez Cabrera, Augusto

    1993-01-01

    Misting is one of the methods which has been proven to be effective in reducing heat stress in dairy cows under very dry and hot weather conditions. We have tested the system in the Guadalquivir Valley. We measured the rectal temperature and respiratory frecuency of heat stressed animals, before and after receiving the cooling treatment. The system did not reduce the body temperature La nebulización de agua es uno de los métodos usados para reducir los sintómas de estrés por calor en ganad...

  18. 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.

  19. Heat transfer study for convection and radiation in an open cavity; Estudio de de la transferencia de calor por convencion y radiacion en una cavidad abierta

    Energy Technology Data Exchange (ETDEWEB)

    Cabanillas Lopez, Rafael E [Universidad de Sonora, Hermosillo, Sonora (Mexico); Estrada Gasca, Claudio A [Centro de Investigacion en Energia-UNAM, Temixco, Morelos (Mexico); Alvarez Garcia, Gabriela S [CENIDET, Cuernavaca, Morelos (Mexico)

    2000-07-01

    Interaction of natural convection and radiation heat transfer in an open side square cavity has been simulated numerically. Previous studies have shown results of the simulation of heat transfer for convection on this geometry. This paper reports the effect of considering both the convection and the radiation mechanisms. Radiation was found to have a great influence on the total amount of heat lost by the cavity as well as on the pattern of flow and on the temperature field. Computations were performed within the domain of the cavity for two-dimensional laminar flow problem. The average of heat transfer coefficient was calculated for several values of the Grashof number for air (Pr = 0.7), with the bottom wall at 500 K (constant temperature) and the open side at 300 K. [Spanish] Se presenta el estudio de la interaccion conveccion natural-radiacion en una cavidad rectangular abierta. Algunos estudios anteriores han mostrado resultados sobre la transferencia de calor por el mecanismo de conveccion natural sobre cavidades abiertas. Aqui se presenta la influencia de considerar ambos mecanismos de transferencia de calor, la conveccion y la radiacion. Se demuestra que el intercambio radiactivo tiene una gran influencia tanto en la cantidad total de calor perdido por la cavidad al ambiente, como en el patron de flujo y de temperatura dentro de la cavidad. Se resuelven numericamente las ecuaciones gobernantes para flujo laminar en dos dimensiones y se calcula el coeficiente promedio de transferencia de calor para diferentes valores del Grashof en una cavidad llena de aire (Pr 0.7), teniendo la pared del fondo de la cavidad a 500 K y los alrededores a 300 K.

  20. Respuestas al estrés por calor en los cultivos. I. Aspectos moleculares, bioquímicos y siológicos.

    Directory of Open Access Journals (Sweden)

    Néstor Felipe Chaves-Barrantes

    2016-12-01

    Full Text Available El objetivo de esta revisión fue integrar los mecanismos por los cuales las plantas responden al estrés por calor a lo largo del continuo suelo-planta-atmósfera, desde una perspectiva agronómica. Esta revisión presenta las bases siológicas del estrés por calor, para lo cual se examinaron las temperaturas óptimas y los umbrales de estrés por calor en los cultivos, las metodologías para su estudio, y las respuestas moleculares, bioquímicas y siológicas de las plantas a altas temperaturas. Se describe el efecto de las altas temperaturas sobre la estructura y el metabolismo celular, la respiración y la aclimatación de la Q10, la estabilidad de las membranas, la acumulación de osmolitos compatibles, la producción de pigmentos y metabolitos secundarios, la producción de especies reactivas de oxígeno (ROS y enzimas antioxidantes, la producción de proteínas de estrés, y el efecto sobre la fotosíntesis y la partición de asimilados. Además, se discuten los cambios hormonales que regulan la respuesta de las plantas en el campo, su señalización y la aclimatación al estrés térmico.

  1. Soldagem por Difusão de Aços Inoxidáveis para Fabricação de Trocadores de Calor Compactos

    Directory of Open Access Journals (Sweden)

    Marcus Vinícius Volponi Mortean

    2016-03-01

    Full Text Available Resumo A união de materiais diferentes ou componentes com geometrias complexas muitas vezes requer processos de uniões especiais, como por exemplo, uma fonte de energia de alta densidade como laser ou feixe de elétrons para soldagem por fusão ou mesmo um processo de soldagem no estado sólido. Em particular, este trabalho descreve os experimentos recentes da aplicação da soldagem por difusão no estado sólido (SDES para diferentes tipos de aços inoxidáveis: austenítico AISI 316L, duplex UNS 31803 e superduplex UNS 327250. A soldagem por difusão foi realizada sob alto vácuo a 1050 °C, durante 60 minutos, empregando uma pressão uniaxial de 18-35 MPa. A qualidade da união foi avaliada por microscopia óptica e testes mecânicos. Os resultados preliminares indicam a necessidade de otimização dos parâmetros de processo para os aços duplex e superduplex. Os resultados positivos alcançados no presente trabalho permitiram a fabricação de protótipos de trocadores de calor compacto em aço inoxidável, utilizando o novo método de fabricação, desenvolvido por LABTUCAL / UFSC, através do qual o processo de corte a jato de água é aplicado para confeccionar com precisão os canais do núcleo do permutador de calor.

  2. Transferência de calor aplicada à prototipagem rápida por deposição de metal em camadas sucessivas utilizando soldagem 3D

    Directory of Open Access Journals (Sweden)

    Felipe Ferreira Fraga

    2013-12-01

    Full Text Available Este trabalho apresenta um estudo dos fenômenos de transferência de calor no processo de prototipagem rápida por deposição de metal em camadas sucessivas utilizando soldagem a arco, também chamada de soldagem 3D (3D Welding. O objetivo é desenvolver um modelo simplificado e compreender o processo de transferência de calor e suas relações com os parâmetros de soldagem, de modo a se possibilitar um controle dos ciclos térmicos a que estará sujeito o material depositado. Desenvolveu-se um modelo físico-matemático para a transferência de calor durante o processo de soldagem, o qual é resolvido numericamente pelo método das diferenças finitas, permitindo a simulação de situações típicas desse tipo de processo de fabricação. O modelo numérico desenvolvido foi validado por meio da simulação de casos específicos para os quais se conhecem soluções analíticas. A partir das equações do modelo, definiram-se parâmetros adimensionais, dentre os quais pode-se citar o grupo adimensional π1, relacionado principalmente à velocidade de soldagem. Realizaram-se alguns experimentos numéricos observando a influência desse grupo nas temperaturas máximas, médias e nas amplitudes dos ciclos térmicos que a peça está sujeita.

  3. Validation of the methodology for the quantitative determination of lead in cosmetics dyes available in the national market by atomic absorption spectroscopy with flame; Validacion de la metodologia para la determinacion cuantitativa de plomo en tintes cosmeticos disponibles en el mercado nacional por espectroscopia de absorcion atomica con llama

    Energy Technology Data Exchange (ETDEWEB)

    Silva Trejos, Paulina [Univ. de Costa Rica, Escuela de Quimica, telefono 2511-4870, fax 2253-5020 (Costa Rica)], E-mail: stpaulinita@gmail.com

    2008-07-15

    The analytical methodology was validated to quantify lead in cosmetics dyes available on the national market, by the method of atomic absorption spectroscopy with flame. The samples were digested by wet digestion with HNO{sub 3} to 65% m/m in a microwave oven, the percentage of recovery for the digestion of samples of 0,25 g and 0,45 g in 5,00 mL was of 100,5{+-}0,5. The field of optimal linearity detection limit was 5,0 mg/L with a correlation coefficient of 0,9998. The limits of detection and quantification limits determined graphically by the method of row errors for linear regression of 0,12{+-}0,02 mg/L and 0,21{+-}0,02 mg/L, respectively. Precision was evaluated determining the repeatability as standard deviation of five replicas of a positive dye for lead, according to the definition of the ISO, 2{radical}2*, and obtained a value of 2,3. The veracity was determined through percentages of recovery assessed, adding aliquots of lead patterns to dye samples and compared with the same mass to which they are not make additions. The dye samples were obtained at point of sale, such as pharmacies, beauty suppliers, supermarkets, sales of natural products and the central market of San Jose. The dyes tested contain lead acetates active ingredient, these are: Doni, Mont D'Or, Matador y Siempre Joven; they are produced locally, Youthair brand and American manufacturing. (author) [Spanish] La metodologia analitica fue validada para determinar cuantitativamente el plomo en tintes cosmeticos disponibles en el mercado nacional, por el metodo de espectroscopia de absorcion atomica con llama. Las muestras se dirigieron por digestion humeda con HNO{sub 3} al 65% m/m en horno de microondas; el porcentaje de recuperacion para la digestion de muestras de 0,25 g y 0,45 g en 5,00 mL fue de 100,5{+-}0,5. El ambito de linialidad optimo fue del limite de deteccion de 5,0 mg/L con un coeficiente de correlacion de 0,9998. Los limites de deteccion y los limites de cuantificacion

  4. IDENTIFICAÇÃO DE ILHAS DE CALOR POR MEIO DE SENSORIAMENTO REMOTO: ESTUDO DE CASO NO MUNICÍPIO DE GOIÂNIA – GO/2001

    Directory of Open Access Journals (Sweden)

    Diego Tarley Ferreira Nascimento

    2009-06-01

    Full Text Available No presente trabalho são utilizadas técnicas de sensoriamento remoto para identificação e análise do fenômeno de ilhas de calor em Goiânia-GO, tendo como recorte temporal o ano de 2001. Foi utilizada a proposta metodológica de Monteiro (1976, do Sistema de Clima Urbano – SCU, em particular o subsistema Termodinâmico, visando proceder a uma análise do funcionamento, desempenho e organização do fenômeno de ilhas de calor. A elaboração do trabalho baseou-se na classificação da cobertura do solo e em um mapeamento do campo térmico do município de Goiânia, por meio das imagens das bandas 3, 4, 5 e 6 (banda termal do Landsat 7, nas quais foram considerados como instrumentos de análise: a urbanização, as características geoecológicas (topografia e o sistema meteorológico (clima regional. Os resultados demonstram que o fenômeno de ilha de calor é constatado no município de Goiânia, havendo diferenças de temperatura de até 10°C entre a área urbana e a rural do município, sendo possível caracterizar determinados usos antrópicos (classes de cobertura do solo e intervalos altimétricos como potencializadores de maiores valores de temperatura.

  5. 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.

  6. 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

  7. Thermal analysis of the heat recuperator of a combined cycle thermoelectric central; Analisis termico del recuperador de calor de una central termoelectrica de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, Hernando; Sanchez, I; Lazcano, L C; Ambriz, Juan Jose; Alvarez, M [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D. F. (Mexico); Gonzalez, O [Comision Federal de Electricidad, Tula (Mexico)

    1997-12-31

    The thermoelectric centrals of the combined cycle type (Brayton Cycle and Rankine Cycle) present a series of opportunities to increase the efficiency of the combined cycle or of the generated power. This paper shows the methodology for the performance of energy balances in a heat recuperator (H. R.), typically employed in the combined cycle stations operating in Mexico, for the assessment of the energy harnessing in the different sections conforming a H. R. The effect of the installation of evaporative coolers and/or an absorption cooling system at the gas turbine compressor intake on the steam generation in the heat recuperator, is evaluated. This extra generation of steam is quantified for its potential use in the same absorption refrigeration system. From the assessment, it follows up that the steam generation in the H.R. is inversely proportional to the ambient temperature and that, although the increased amount of steam generated can not be harnessed in total by the steam turbine, the remaining fraction is good enough to cover the heat demand for the operation of the refrigeration system. [Espanol] Las centrales termoelectricas del tipo ciclo combinado (ciclo Brayton y ciclo Rankine) presentan un conjunto de oportunidades para incrementar la eficiencia del ciclo combinado o bien la potencia generada. En el presente trabajo se expone la metodologia para realizar los balances de energia en un recuperador de calor (R.C.) tipicamente utilizado en las Centrales de Ciclo Combinado (CCC) que operan en Mexico, para evaluar el aprovechamiento de la energia en las diferentes secciones que conforman un R.C. Se evalua el efecto que tiene la instalacion de enfriadores evaporativos y/o un sistema de enfriamiento por absorcion en la succion del compresor de la turbina de gas sobre la generacion de vapor en el recuperador de calor. Se cuantifica esta generacion extra de vapor para su posible utilizacion en el mismo sistema de refrigeracion por absorcion. De la evaluacion se

  8. Thermal analysis of the heat recuperator of a combined cycle thermoelectric central; Analisis termico del recuperador de calor de una central termoelectrica de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, Hernando; Sanchez, I.; Lazcano, L. C.; Ambriz, Juan Jose; Alvarez, M. [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D. F. (Mexico); Gonzalez, O. [Comision Federal de Electricidad, Tula (Mexico)

    1996-12-31

    The thermoelectric centrals of the combined cycle type (Brayton Cycle and Rankine Cycle) present a series of opportunities to increase the efficiency of the combined cycle or of the generated power. This paper shows the methodology for the performance of energy balances in a heat recuperator (H. R.), typically employed in the combined cycle stations operating in Mexico, for the assessment of the energy harnessing in the different sections conforming a H. R. The effect of the installation of evaporative coolers and/or an absorption cooling system at the gas turbine compressor intake on the steam generation in the heat recuperator, is evaluated. This extra generation of steam is quantified for its potential use in the same absorption refrigeration system. From the assessment, it follows up that the steam generation in the H.R. is inversely proportional to the ambient temperature and that, although the increased amount of steam generated can not be harnessed in total by the steam turbine, the remaining fraction is good enough to cover the heat demand for the operation of the refrigeration system. [Espanol] Las centrales termoelectricas del tipo ciclo combinado (ciclo Brayton y ciclo Rankine) presentan un conjunto de oportunidades para incrementar la eficiencia del ciclo combinado o bien la potencia generada. En el presente trabajo se expone la metodologia para realizar los balances de energia en un recuperador de calor (R.C.) tipicamente utilizado en las Centrales de Ciclo Combinado (CCC) que operan en Mexico, para evaluar el aprovechamiento de la energia en las diferentes secciones que conforman un R.C. Se evalua el efecto que tiene la instalacion de enfriadores evaporativos y/o un sistema de enfriamiento por absorcion en la succion del compresor de la turbina de gas sobre la generacion de vapor en el recuperador de calor. Se cuantifica esta generacion extra de vapor para su posible utilizacion en el mismo sistema de refrigeracion por absorcion. De la evaluacion se

  9. The determination of sulphur in materials of high neutron absorption cross-section by fast-neutron activation analysis; Determination du soufre dans les matieres de forte section efficace d'absorption neutronique, au moyen d'une analyse par activation avec des neutrons rapides; Opredelenie sery v materialakh s bol'shim secheniem pogloshcheniya nejtronov metodom aktivatsionnogo analiza bystrykh nejtronov; Determinacion del azufre en sustancias de elevada seccion eficaz de absorcion neutronica mediante analisis por activacion con neutrones rapidos

    Energy Technology Data Exchange (ETDEWEB)

    Gibbons, D; Simpson, H [Wantage Research Laboratory (A.E.R.E.), Wantage, Berks. (United Kingdom)

    1962-01-15

    The production of radiophosphorus by the fast neutron (n, p) reaction on sulphur is used for the determination of sulphur by activation analysis. Using this technique it is possible to determine sulphur in materials of high thermal-neutron absorption cross-section because the absorption cross-sections for fast neutrons are, in general, much lower than those for slow neutrons, so that self-shielding errors are considerably reduced. Interference due to the slow neutron (n, {gamma}) reaction on neutral phosphorus is eliminated by a double irradiation technique involving irradiation in regions of differing slow/fast flux-ratios. The method has been applied to the determination of sulphur in chromium and arsenic. (author) [French] La production de radiophosphore par reaction (n, p) de neutrons rapides sur le soufre est utilisee pour la determination du soufre au moyen d'une analyse par activation. Cette methode permet la determination du soufre dans les matieres de forte section efficace d'absorption des neutrons thermiques; en effet, les sections efficaces d'absorption des neutrons rapides sont, d'une maniere generale, beaucoup plus faibles que pour les neutrons lents, de sorte que les erreurs d'autoprotection se trouvent considerablement reduites. L'interference due a la reaction (n, {gamma}) des neutrons lents sur le phosphore naturel est eliminee par une double irradiation, qui implique une irradiation dans les regions ou le rapport du flux de neutrons lents au flux de neutrons rapides a des valeurs differentes. La methode a ete appliquee a la determination du soufre dans le chrome et l'arsenic. (author) [Spanish] La formacion de fosforo radiactivo por la accion de los neutrones rapidos sobre el azufre, reaccion (n, p), puede servir para determinar este elemento mediante analisis por activacion. El empleo de esta tecnica permite efectuar determinaciones de azufre en materiales de elevada seccion eficaz de absorcion de neutrones termicos porque, en general, las

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

    Directory of Open Access Journals (Sweden)

    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

  11. Solución de problemas inversos en conducción de calor mediante el método de simulación por redes

    OpenAIRE

    Zueco Jordán, Joaquín

    2009-01-01

    En la presente tesis doctoral se resuelven diferentes problemas inversos en conducción del calor mediante una serie de protocolos de resolución desarrollados y partiendo de medidas de temperaturas efectuadas en diferentes puntos del medio. Se establecen, dentro del campo de la transmisión del calor, nuevos procedimientos de estimación de funciones (que pueden ser extendidos al problema de estimación de parámetros) basados en el uso de funciones continuas del tipo "lineal a tramos" (piece wise...

  12. 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

  13. 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.

  14. 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

  15. Cálculo por dinámica y mecánica molecular de sitios y calores de adsorción de Dipentenos sobre Zeolita Y

    Directory of Open Access Journals (Sweden)

    Cristian Blanco

    2011-06-01

    Full Text Available Hemos utilizado métodos de la mecánica molecular para estudiar la adsorción de R-limoneno, p-ment-1-eno, p-ment-8-eno y p-mentano sobre faujasita silícea y sobre zeolitas Y con relación Si/Al = 2 que contenían diferentes cationes en el sitio SII (Nal+, Fe2+, FeH y MnH. Los cálculos mostraron que la presencia de dobles enlaces en la molécula que se adsorbe y el tipo de catión en SIl determinan la estabilidad del complejo adsorbatozeolita. Las interacciones entre el huésped y la molécula adsorbida estuvieron dominadas por las contribuciones electrostáticas, las cuales aumentaron con la carga del catión en SII. La orientación de las moléculas insaturadas en la supercaja fue resultado del balance entre el aumento de repulsiones estéricas entre zeolita y molécula adsorbida y el aumento de atracciones electrostáticas como resultado de la minimización de dos grupos de distancias: las distancias entre el catión en SII y los carbonos Sp2 de la molécula adsorbida y las distancias entre los oxígenos estructurales de la zeolita y los hidrógenos de la molécula adsorbida.

  16. 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.

  17. Metodología de simulación numérica de la transferencia de calor por ebullición en película en torno a superficies esféricas refrigeradas por líquido saturado en convección libre: aplicación a reactores nucleares de lecho de bolas (PBR)

    OpenAIRE

    Arévalo Ramírez, Rubén

    2015-01-01

    En la presente Tesis se realizó un análisis numérico, usando el código comercial Ansys-Fluent, de la refrigeración de una bola de combustible de un reactor de lecho de bolas (PBR, por sus siglas en inglés), ante un escenario de emergencia en el cual el núcleo sea desensamblado y las bolas se dejen caer en una piscina de agua, donde el mecanismo de transferencia de calor inicialmente sería la ebullición en película, implicando la convección y la radiación al fluido. Previamente se realizaron p...

  18. Ractopamine levels for finishing barrows maintained in heat stress Níveis de ractopamina para suínos machos castrados em terminação mantidos sob estresse por calor

    Directory of Open Access Journals (Sweden)

    Josilene Figueiredo Sanches

    2010-07-01

    Full Text Available The objective of this study was to evaluate performance, quantitative characteristics of carcass, and visceral responses of barrows maintained on heat stress enviroment and fed diets supplemented with ractopamine. It was used 48 animals with initial weight of 67.3 ± 3.8 kg, distributed in a randomized block design with four levels of ractopamine (0, 5, 10 and 20 mg/kg, each one with six replicates with two animals each. The experimental period lasted 28 days. Air temperature was 31.8 ± 2.0ºC, air humidity was 72.6 ± 10.2% and BGHI was 82.7 ± 2.8. Daily feed intake was not affect by the levels of ractopamine but they improved feed conversion and increased daily weight gain and final weight of the animals. The carcass quantitative characteristics were not affected by levels of ractopamine. The weights of the liver and kidneys showed linear increases accordingly to increase of ractopamine levels in the diet whereas weight of other organs and length of small intestine were not affected by supplementation with ractopamine. The optimum level of ractopamine for the best performance of barrows under heat stress is 20 mg/kg and it does not affect the quantitative characteristics of carcass.Avaliaram-se o desempenho, as características quantitativas de carcaça e as respostas viscerais de suínos machos castrados mantidos em ambiente de estresse por calor e alimentados com dietas suplementadas com ractopamina. Foram utilizados 48 animais com peso inicial de 67,3 ± 3,8 kg, distribuídos em delineamento em blocos casualizados, com quatro níveis de ractopamina (0, 5, 10 e 20 mg/kg, cada um com seis repetições de dois animais. O período experimental foi de 28 dias. A temperatura do ar foi de 31,8 ± 2,0ºC, a umidade relativa foi de 72,6 ± 10,2% e índice de temperatura de globo e umidade (ITGU de 82,7 ± 2,8. Os níveis de ractopamina não influenciaram o consumo diário de ração, mas melhoraram a conversão alimentar e aumentaram o ganho di

  19. Precisão da medida do limiar anaeróbio por meio do calorímetro portátil Precisión de la medición del umbral anaerobio por medio del calorímetro portátil Measurement precision of the anaerobic threshold by means of a portable calorimeter

    Directory of Open Access Journals (Sweden)

    Fernando dos Santos Nogueira

    2010-09-01

    Full Text Available FUNDAMENTO: Muitos métodos são empregados para determinar o Limiar Anaeróbio (LAn por meio de ergoespirômetros sofisticados. OBJETIVO: Testar a variação no LAn, detectado por modelos matemáticos e de inspeção visual, quando empregado ergoespirômetro de baixo custo e destinado à aplicação clínica. MÉTODOS: Foram voluntários para esse estudo 79 indivíduos aparentemente saudáveis; desses, 57 homens. O VO2máx e o limiar ventilatório foram determinados por calorimetria indireta de circuito aberto. O método eletroenzimático foi empregado para análise da lactacidemia e determinação direta do limiar de lactato (LL. O LAn foi determinado por dois métodos matemáticos (MM SQR e MMslope, baseados nas trocas gasosas, e pelo método de inspeção visual do log-log, para determinação do LL. Dois pesquisadores independentes determinaram o LAn através da inspeção visual de três gráficos, considerando dois métodos (LAn-a= V-slope, EqV; e LAn-b = V-slope, EqV e ExCO2. Os dados foram analisados por meio da estatística paramétrica para determinação das diferenças entre LAn-a versus ExCO2, MM SQR e MMslope; LAn-b versus MM SQR e MMslope; e LL versus LAn-a, LAN-b, MM SQR e MMslope. RESULTADOS: O MMslope foi o único método que apresentou diferença significativa entre o LAn-a e LAn-b (p=0,001, com CV% >15. O LL versus MMslope não apresentou diferença significativa (p=0,274, contudo, observou-se um elevado CV (24%. CONCLUSÃO: Conclui-se que com o equipamento de baixo custo os métodos MM SQR e LAn-a podem ser utilizados para a determinação do LAn. O método MMslope não apresentou precisão satisfatória para ser empregado com esses equipamentos.FUNDAMENTO: Muchos métodos se emplean para que se determine el Umbral Anaerobio (UAn por medio de ergoespirómetros sofisticados. OBJETIVO: Probar la variación en el UAn, detectado por modelos matemáticos y de inspección visual, cuando empleado ergoespirómetro de bajo costo y

  20. Caracterização de concentrado protéico de folhas de mandioca obtido por precipitação com calor e ácido Characterization of cassava leaf protein concentrate obtained by heat and acid precipitation

    Directory of Open Access Journals (Sweden)

    Cláudia de Fátima Modesti

    2007-09-01

    Full Text Available As folhas de mandioca apresentam um teor elevado de proteínas, todavia sua digestibilidade é baixa. A produção de concentrado protéico de folhas de mandioca (CPFM permite a utilização das proteínas das folhas com um reduzido teor de fibras e melhor qualidade protéica. Neste trabalho, analisaram-se características químicas de CPFM obtidos por diferentes formas de precipitação, com calor e com ácido. Os CPFM praticamente não apresentaram diferenças na composição centesimal. O nível de proteína dos CPFM aumentou 57,72% em comparação ao da farinha de folhas de mandioca (FFM. Os rendimentos de extração das proteínas também foram semelhantes para os CPFM. O teor de Fe dos CPFM foi mais elevado quando comparado com o da FFM. A FFM apresentou absorção de água e de óleo mais elevada que os CPFM, mas, entre os tipos de CPFM, os resultados foram semelhantes. A mínima solubilidade de nitrogênio da FFM e dos CPFM foi observada em pH entre 3 e 5. Verificou-se que a FFM apresentou uma capacidade de formação e estabilidade de espuma mais elevada que os CPFM. Tanto a FFM quanto os CPFM não apresentaram boa estabilidade de emulsão.Cassava leaves have a high content of protein of low digestibility. The production of cassava leaf protein concentrate (CLPC enables cassava leaf protein to be used with a reduced fiber content and better protein quality. This work involved an investigation of the chemical characteristics of CLPC produced by different forms of precipitation, using heat and acid. No significant differences were found in the centesimal composition of the CLPC. The protein content in CLPC was 57.72% higher than in cassava leaf flour (CLF. Both types of CLPC precipitation also yielded similar protein concentrations. The CLPC Fe content was higher than that of the CLF. The CLF presented higher water and oil absorption than did CLPC, although the CLPC extracted by the two methods showed similar results. The lowest nitrogen

  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. Heat transfer coefficients obtainment by means of naphthalene sublimation in air; Obtencion de coeficientes de transferencia de calor por medio de la tecnica de sublimacion de naftalina en aire

    Energy Technology Data Exchange (ETDEWEB)

    Perez Galindo, Jose Arturo; Garcia Gutierrez, Alonso [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    This work describes the experimental technique for the sublimation of naphthalene in air which measures heat transfer coefficients through the use of the analogy between the transference phenomena of heat and mass. The technique used to substitute the experimental measurements of heat transfer, in which it is difficult to control the border thermal conditions, when they are dimmed by the omnipresent problem of heat conduction through the walls of the transference surfaces. Two examples are included of the application technique and its potential is outlined. [Espanol] En este trabajo se describe la tecnica experimental de la sublimacion de naftalina en aire mediante la que se miden coeficientes de transferencia de masa. Los datos asi obtenidos pueden convertirse en coeficientes de transferencia de calor a traves del uso de la analogia entre los fenomenos de transferencia de calor y masa. La tecnica se utiliza para substituir las mediciones experimentales de transferencia de calor, en las que es dificil controlar las condiciones termicas de frontera, cuando las empana el problema omnipresente de la conduccion de calor a traves de las paredes de las superficies de transferencia. Se incluyen dos ejemplos de la aplicacion de la tecnica y se destaca su potencial.

  3. Heat transfer coefficients obtainment by means of naphthalene sublimation in air; Obtencion de coeficientes de transferencia de calor por medio de la tecnica de sublimacion de naftalina en aire

    Energy Technology Data Exchange (ETDEWEB)

    Perez Galindo, Jose Arturo; Garcia Gutierrez, Alonso [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1985-12-31

    This work describes the experimental technique for the sublimation of naphthalene in air which measures heat transfer coefficients through the use of the analogy between the transference phenomena of heat and mass. The technique used to substitute the experimental measurements of heat transfer, in which it is difficult to control the border thermal conditions, when they are dimmed by the omnipresent problem of heat conduction through the walls of the transference surfaces. Two examples are included of the application technique and its potential is outlined. [Espanol] En este trabajo se describe la tecnica experimental de la sublimacion de naftalina en aire mediante la que se miden coeficientes de transferencia de masa. Los datos asi obtenidos pueden convertirse en coeficientes de transferencia de calor a traves del uso de la analogia entre los fenomenos de transferencia de calor y masa. La tecnica se utiliza para substituir las mediciones experimentales de transferencia de calor, en las que es dificil controlar las condiciones termicas de frontera, cuando las empana el problema omnipresente de la conduccion de calor a traves de las paredes de las superficies de transferencia. Se incluyen dos ejemplos de la aplicacion de la tecnica y se destaca su potencial.

  4. Avaliação da resistência a corrosão de revestimentos metálicos depositados por aspersão térmica a arco: uma aplicação em trocadores de calor

    Directory of Open Access Journals (Sweden)

    Rodrigo Cardoso Costa

    2014-12-01

    Full Text Available Tubos de trocadores de calor de usinas termoelétricas a carvão sofrem desgaste corrosivo devido à presença de enxofre e condensação dos gases da combustão, tendo por consequência uma redução na eficiência global do equipamento. Uma opção para o aumento da resistência à corrosão em meios agressivos é a utilização de revestimentos aplicados pela tecnologia de aspersão térmica. A resistência à corrosão dá-se com o emprego de materiais mais resistentes que o substrato. Dentre os processos existentes de aspersão térmica, o que utiliza o arco elétrico como fonte de energia (Arc Spray, possui alta taxa de deposição e menor custo operacional, sendo assim, escolhido para o estudo. Para a determinação do melhor revestimento a ser utilizado, foram testadas ligas metálicas resistentes à corrosão, em comparação com o material empregado nos tubos dos trocadores de calor, ASTM 178A. A seleção do revestimento mais resistente foi feita por meio de ensaio de corrosão acelerada em câmara de SO2 e também através do ensaio de polarização. Verificou-se que o revestimento de alumínio apresentou os melhores resultados nos testes realizados, quando comparados com material utilizado atualmente nos trocadores de calor (ASTM 178A.

  5. 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

  6. Software for the design of acoustical steam silencers of the reaction-absorption type; Software para el diseno de silenciadores acusticos de vapor del tipo reaccion-absorcion

    Energy Technology Data Exchange (ETDEWEB)

    Buendia Dominguez, Eduardo H; Alvarez Chavez, Jose M [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    This paper describes the computer program named SILRA, that determines the outline dimensions of an acoustic steam silencer of the reaction-absorption type. These silencers are employed in the geothermoelectric power plants to lower the high levels of pressure and sound caused by the steam discharge to the surrounding atmosphere. The program has the capacity of predicting the noise level generated by the discharge without silencer depending on the emitting source. On SIRLA was successfully coupled the theory described in specialized literature with optimization techniques and experiences acquired in former designs. SIRLA is a powerful tool that allows the designer to optimize the equipment as well as the design time. [Espanol] En este trabajo se describe el programa de computo SILRA, que determina las dimensiones generales de un silenciador acustico de vapor tipo reaccion-absorcion, estos silenciadores se emplean en las centrales geotermoelectricas para abatir los altos niveles de presion de sonido provocados por la descarga del vapor a la atmosfera. El programa tiene la capacidad de predecir el nivel de ruido que genera la descarga sin silenciador, dependiendo de la fuente emisora. En SILRA se acoplaron con exito la teoria descrita en la literatura especializada con tecnicas de optimacion y experiencias adquiridas en disenos anteriores. SILRA es una poderosa herramienta que permite al disenador optimar tanto el equipo como el tiempo de diseno.

  7. Software for the design of acoustical steam silencers of the reaction-absorption type; Software para el diseno de silenciadores acusticos de vapor del tipo reaccion-absorcion

    Energy Technology Data Exchange (ETDEWEB)

    Buendia Dominguez, Eduardo H.; Alvarez Chavez, Jose M. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    This paper describes the computer program named SILRA, that determines the outline dimensions of an acoustic steam silencer of the reaction-absorption type. These silencers are employed in the geothermoelectric power plants to lower the high levels of pressure and sound caused by the steam discharge to the surrounding atmosphere. The program has the capacity of predicting the noise level generated by the discharge without silencer depending on the emitting source. On SIRLA was successfully coupled the theory described in specialized literature with optimization techniques and experiences acquired in former designs. SIRLA is a powerful tool that allows the designer to optimize the equipment as well as the design time. [Espanol] En este trabajo se describe el programa de computo SILRA, que determina las dimensiones generales de un silenciador acustico de vapor tipo reaccion-absorcion, estos silenciadores se emplean en las centrales geotermoelectricas para abatir los altos niveles de presion de sonido provocados por la descarga del vapor a la atmosfera. El programa tiene la capacidad de predecir el nivel de ruido que genera la descarga sin silenciador, dependiendo de la fuente emisora. En SILRA se acoplaron con exito la teoria descrita en la literatura especializada con tecnicas de optimacion y experiencias adquiridas en disenos anteriores. SILRA es una poderosa herramienta que permite al disenador optimar tanto el equipo como el tiempo de diseno.

  8. High-Temperature Gas-Cooled Reactor Critical Experiment and its Application to Thorium Absorption Rates; Experience Critique pour l'Etude d'un Reacteur a Haute Temperature, Refroidi par un Gaz et son Application a la Determination des Taux d'Absorption du Thorium; Kriticheskij opyt, postavlennyj na vysokotemperaturnom reaktore s gazovym okhlazhdeniem, i primenenie ego dlya opredeleniya stepeni pogloshcheniya toriya; Experimento Critico Efectuado en un Reactor de Elevada Temperatura Refrigerado por Gas y su Aplicacion para Calcular los Indices de Absorcion del Torio

    Energy Technology Data Exchange (ETDEWEB)

    Bardes, R. G.; Brown, J. R.; Drake, M. K.; Fischer, P. U.; Pound, D. C.; Sampson, J. B.; Stewart, H. B. [General Dynamics Corporation,San Diego, CA (United States)

    1964-04-15

    variations en fonction de la temperature (coefficient Doppler d'activation). Pour mesurer le coefficient Doppler par oscillation de la reactivite, on se sert de la totalite de la cartouche centrale au cours d'une operation qui permet de la porter a une temperature pouvant atteindre 425 Degree-Sign C et d'eliminer experimentalement les effets qui ne contribuent pas a la capture de neutrons de resonance par le thorium. Pour toute une gamme d'experiences, les resultats obtenus concordent bien avec les resultats theoriques. Le memoire decrit la mesure de l'integrale de resonance pour le thorium et ses variations en fonction de la temperature. Dans le procede que l'on a mis au point pour mesurer la capture de resonance, on utilise l'or comme etalon et le vanadium comme matiere donnant le taux d'absorption en 1/v. Ce procede a ete choisi parce que le thorium est disperse dans le graphite et qu'il est difficile d'appliquer le procede habituel du rapport cadmium. Les resultats empiriques concordent bien avec les resultats theoriques dans une large gamme de variables. En outre, les resultats des mesures du coefficient Doppler par les deux methodes (oscillation de la reactivite et activation) concordent. Les auteurs estiment que ce fait merite d'etre releve, car dans les ouvrages publies jusqu'ici ces deux procedes donnaient des resultats differents. (author) [Spanish] Al definir los principios teoricos del reactor de elevada temperatura refrigerado por gas, y de su primer prototipo en Peach Bottom, la General Atomic decidio efectuar un experimento critico con miras a reunir ciertos datos de entrada requeridos para el analisis nuclear. Debido a las necesidades especificas de la teoria de las construcciones nucleares, en lo que atane a los datos de entrada acerca de la absorcion del torio, los autores elaboraron un sistema experimental formado por un conjunto critico con reticulado central rodeado por una region amortiguadora y otra activado'. Este tipo de conjunto, en el que el

  9. The GEANT-CALOR interface

    International Nuclear Information System (INIS)

    Zeitnitz, C.; Gabriel, T.A.

    1994-01-01

    The simulation of large scale high energy physics experiments is based mainly on the GEANT package. In the current version 3.15 the simulation of hadronic interacting particles is based on GHEISHA or FLUKA. Both programs miss an accurate simulation of the interaction of low energy neutrons (E kin < 20 MeV) with the materials of the detector. The CALOR89 program package contains a low energetic neutron code. An interface between the CALOR program parts and the GEANT package has been developed

  10. Efeito do chá verde (Camelia sinensis em ratos com obesidade induzida por dieta hipercalórica Antiobesity effects of green tea (Camelia sinensis in high caloric diet-induced obese rats

    Directory of Open Access Journals (Sweden)

    Marta Vera-Cruz

    2010-10-01

    Full Text Available INTRODUÇÃO: A obesidade é fator de risco para várias doenças. Estudos têm demonstrado que os polifenóis do chá verde auxiliam na perda de peso e interferem nos mecanismos de diversas doenças. A insulina, agindo por meio de seu receptor (IR, desencadeia uma série de respostas. A via IR/Shc é ligada ao crescimento celular e à mitogênese. OBJETIVOS: Estudar o efeito do chá verde no peso corporal e no teste de tolerância à glicose (GTT. No fígado, estudar a fosforilação do IR, a presença e a expressão de IR e Shc e suas alterações morfológicas. MATERIAL E MÉTODOS: Ratos Wistar, jovens e tratados com dieta hipercalórica ou dieta própria para ratos, foram submetidos a tratamento com chá verde. Para retirada do fígado, após anestesia, foi infundida insulina ou solução salina. Para avaliar o grau de fosforilação do IR, o fragmento foi homogeneizado e submetido a técnicas de imunoprecipitação e imunoblotting. Para análise morfológica, foi utilizada a técnica de coloração por hematoxilina e eosina e para localizar a presença de IR e Shc, técnica de imuno-histoquímica. RESULTADOS E CONCLUSÃO: Observamos diminuição do peso corporal e da esteatose no fígado e melhora no GTT. Houve aumento da fosforilação do IR no fígado dos animais obesos tratados com relação aos obesos não submetidos a tratamento. Verificaram-se lesões que poderiam ser associadas ao tratamento, como necrose focal. A análise imuno-histoquímica demonstrou presença de IR e Shc em todos os grupos estudados e sugeriu alterações na expressão de IR e Shc nos grupos obesos e obesos tratados.INTRODUCTION: Obesity is a risk factor for several diseases. Studies have shown that polyphenols in green tea aid in weight loss and influence the mechanisms of several diseases. Insulin, acting through its receptor (IR, triggers a series of responses. IR/Shc pathway is linked to cell growth and mitogenesis. OBJECTIVES: To investigate the effect of

  11. 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.

  12. 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…

  13. La isla de calor estival en Temuco, Chile

    OpenAIRE

    Alicia Capelli de Steffens; María Cintia Píccolo; Jorge Hernández González; Gustavo Navarrette

    2001-01-01

    Temuco es una ciudad localizada en el centro sur de Chile (38º 45 S y 72º 40 W). Morfológicamente, el sitio de la ciudad corresponde a las terrazas fluviales del río Cautín que se desarrollan en forma encajonada entre los cerros Ñielol (350 m) y Conunhueno (360 m). Esta ciudad se ha desarrollado rápidamente en las últimas décadas, por lo tanto es necesario conocer el efecto antrópico en la misma. Para evaluar parte de ese efecto se analiza la isla de calor urbana estival en la ...

  14. A crise do socialismo analisada no calor da hora

    Directory of Open Access Journals (Sweden)

    Reginaldo Benedito Dias

    2009-11-01

    Full Text Available O presente artigo demonstra como os acontecimentos que levaram à crise e desintegração dos países do bloco soviético foram analisados no calor dos acontecimentos, tomando como parâmetro os livros "Nós, o povo" e "A desintegração do monolito", selecionados por causa das diferentes perspectivas metodológicas e ideológicas que representam.  

  15. 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.

  16. Níveis de lisina digestível em rações, em que se manteve ou não a relação aminoacídica, para frangos de corte de 1 a 21 dias de idade, mantidos em estresse por calor

    Directory of Open Access Journals (Sweden)

    Valerio Sandra Roseli

    2003-01-01

    Full Text Available Dois ensaios foram conduzidos para avaliar os efeitos de níveis de lisina digestível em rações em que se manteve ou não a relação aminoacídica sobre o desempenho de frangos de corte machos de 1 a 21 dias de idade, criados em alta temperatura. O delineamento experimental utilizado em ambos os ensaios foi o inteiramente casualizado. As aves, no ensaio 1, foram distribuídas em cinco tratamentos (0,92; 0,98; 1,04; 1,10 e 1,16% de lisina digestível em ração convencional, oito repetições e dez aves por repetição. No ensaio 2, os frangos foram distribuídos em quatro tratamentos (1,04; 1,10; 1,16 e 1,22% de lisina digestível em rações mantendo a relação aminoacídica, oito repetições e dez aves por repetição. No ensaio 1, os tratamentos influenciaram quadraticamente o ganho de peso e o consumo de ração, que aumentaram até os níveis de 1,14 e 1,09% de lisina, respectivamente. Embora a conversão alimentar tenha melhorado de forma linear, o modelo LRP foi o que melhor se ajustou aos dados, estimando em 1,097% o nível de lisina a partir do qual ocorreu um platô. Não houve efeito dos tratamentos sobre os pesos absolutos do coração, fígado e intestinos, enquanto o peso absoluto da moela aumentou linearmente. O peso absoluto da carcaça aumentou, enquanto os pesos relativos do coração e do fígado reduziram quadraticamente com os tratamentos. No ensaio 2, os tratamentos influenciaram de forma linear crescente o ganho de peso e a conversão alimentar, enquanto o consumo de ração não variou. Os tratamentos influenciaram linearmente o peso absoluto da carcaça, enquanto os pesos absoluto e relativo das vísceras não variaram. Concluiu-se que frangos de corte machos, de 1 a 21 dias de idade, mantidos em estresse por calor, exigem, no mínimo, 1,14 e 1,22% de lisina digestível em ração convencional e em ração em que se manteve a relação aminoacídica, respectivamente.

  17. 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...... studies were identified. The majority of the prospective studies found positive associations between intake of calorically sweetened beverages and obesity. Three experimental studies found positive effects of calorically sweetened beverages and subsequent changes in body fat. Two experimental studies did...... 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...

  18. 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.

  19. 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.

  20. La isla de calor estival en Temuco, Chile

    Directory of Open Access Journals (Sweden)

    Alicia Capelli de Steffens

    2001-01-01

    Full Text Available Temuco es una ciudad localizada en el centro sur de Chile (38º 45’ S y 72º 40’ W. Morfológicamente, el sitio de la ciudad corresponde a las terrazas fluviales del río Cautín que se desarrollan en forma encajonada entre los cerros Ñielol (350 m y Conunhueno (360 m. Esta ciudad se ha desarrollado rápidamente en las últimas décadas, por lo tanto es necesario conocer el efecto antrópico en la misma. Para evaluar parte de ese efecto se analiza la isla de calor urbana estival en la ciudad de Temuco, Chile. Se efectuaron mediciones de temperatura del aire y humedad a través de la ciudad para determinar la forma y la intensidad de la isla de calor urbano. Se utilizaron estaciones móviles e información de una estación meteorológica fija. La ciudad presenta un comportamiento térmico diferente a lo largo del día. Durante el día genera una isla de calor que responde en líneas generales al modelo ideal de calentamiento urbano. La intensidad de la isla calórica (∆Tu-r fue 6.3ºC y 1.2ºC durante el día y la noche, respectivamente. La influencia de los cerros que limitan la ciudad es importante. El estudio confirma la idea que el clima urbano de una ciudad es un mosaico de microclimas que interactuan continuamente.

  1. Asymmetry dependence of the nuclear caloric curve

    International Nuclear Information System (INIS)

    McIntosh, A.B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L.W.; Marini, P.; Raphelt, A.; Souliotis, G.A.; Wuenschel, S.; Zarrella, A.; Yennello, S.J.

    2013-01-01

    A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron–proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A=50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry (N−Z)/A . An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei

  2. Influencia de adyuvantes sobre la absorcion y translocacion de 14C glifosato en coquito, Cyperus rotundus

    Directory of Open Access Journals (Sweden)

    Plaza Guido A.

    1997-06-01

    Full Text Available

    EI uso de aditivos puede mejorar notablemente la homogeneidad de la mezcla del herbicida, la interacción de la actividad del ingrediente activo con la planta objetivo, o ambas características. Cyperus rotundus L., es una de las malezas mas importantes de las regiones del trópico y subtropico cálido del mundo. EI Glifosato dentro de sus características presenta la no selectividad, actividad posemergente y gran movilidad en el interior de las plantas. EI uso de adyuvantes (promedio de la actividad del sulfato de amonio, Synperonic A2, A7, A20 y Kemkol, aceite diesel y mezclas entre adyuvantes, mejoro la absorción del glifosato en los diferentes tiempos evaluados. Por ejemplo, a las 24 horas, el incremento fue del 2%, a las 48 horas este valor fue cercano al 3% y a las 72 horas fue del 1,8%. Este beneficio se vio reflejado en la calidad del control y en la reducción del numero de nuevas macollas producidas por las plantas tratadas. La mezcla de sulfato de amonio y los surfactantes Synperonic A7 y A2 mejoro la absorción del glifosato.

    Palabras Claves: Glyphosate, Adjuvants, Cyperus rotundus, #3 CYPRO

  3. 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.

  4. Non-Destructive Examination of the Heat-Affected Zone of Welded Zr-Nb Alloy; Controle Non Destructif de la Zone d'Un Alliage Zr-Nb Affectee par la Chaleur Lors du Soudage; Nedestruktivnoe ispytanie zony svarnogo shva iz tsirkonij-niobij splava, kotoryj podverzhen teplovomu vliyaniyu; Examen No Destructivo de la Zona de Soldadura Afectada por el Calor en las Aleaciones de Circonio y Niobio

    Energy Technology Data Exchange (ETDEWEB)

    Hanstock, R. F.; Walker, D. C.B. [U.K.A.E.A. Reactor Materials Laboratory, Culcheth (United Kingdom)

    1965-10-15

    chaleur qui sont susceptibles de corrosion pouvaient etre decelees par controle non destructif, en mesurant le potentiel thermoelectrique aux bornes d'une sonde metallique chauffee, en contact avec des parties determinees de la soudure et le metal adjacent. La sonde thermoelectrique est similaire a celle mise au point par l'Association britannique de recherches sur les metaux non ferreux en vue de mesurer l'epaisseur des revetements de plaques de metal; un instrument en vente sur le marche et muni de ce type de sonde peut etre utilise, apres une legere modification, pour le controle des soudures dans les alliages Zr-Nb. Le memoire donne un exemple de la variation de la reponse de la sonde dans des zones affectees par la chaleur lors du sondage; les resultats sont compares a ceux d'un examen en autoclave. (author) [Spanish] Las aleaciones de circonio con 2 Vulgar-Fraction-One-Half % de niobio ofrecen, gracias al tratamiento termico, la ventaja de resistir la presion en los reactores moderados por agua. Por otra parte, ese tratamiento afecta considerablemente a la resistencia a la corrosion en las condiciones de funcionamiento del reactor, siendo de seuealar que pueden surgir puntos especialmente vulnerables en las zonas de las soldaduras sometidas al calor. Las zonas susceptibles de corrosion pueden localizarse mediante tratamiento en autoclase, pero no es conveniente aplicarlo cuando extensos circuitos de presion se arman mediante soldadura. Se ha comprobado que las zonas afectadas por el calor que son vulnerables a la corrosion pueden localizarse por metodos no destructivos consistentes en medir el potencial termoelectrico entre la punta de una sonda metalica caliente en contacto con determinadas partes de la soldadura y el del metal adyacente. La sonda es analoga a la que ha diseueado la British-ferrous Metals Research Association para medir el espesor del chapado de sustratos metalicos. Los instrumentos comerciales equipados con ese tipo de sonda sirven con una

  5. 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.

  6. Isla de calor y ocupación espacial urbana en San Juan, Argentina: análisis evolutivo

    OpenAIRE

    Papparelli, Alberto; Kurbán, Alejandra; Cúnsulo, Mario

    2013-01-01

    En este articulo se presentan resultados finales de un proyecto de investigacion bianual (2009-2010), denominado Variación histórica y espacial de la isla de calor urbana en zona árida, financiado por la Universidad Nacional de San Juan, Argentina. Su objetivo principal es determinar la progresiva modificacion de la isla de calor urbana en un periodo de quince anos (1995-2010) y la correlacion de esta con la ocupacion del area urbana del Gran San Juan (GSJ), localizada en la diagonal arida de...

  7. Uptake, retention and excretion of strontium in man; Assimilation, retention et excretion du strontium chez l'homme; Pogloshchenie, zaderzhka i vydelenie strontsiya organizmom cheloveka; Absorcion, retencion y excrecion del estroncio en el hombre

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, G. E. [Radiobiological Research Unit, Medical Research Council, Harwell (United Kingdom)

    1963-02-15

    de l'excretion urinaire et de la retention du {sup 85}Sr contenu dans 'alimentation faisant l'objet de l'experience. Il determine egalement les excretions fecales endogenes. Il compare ces resultats a ceux que l'on obtient a la suite d'une seule injection intraveineuse de radiostrontium. Dans le cas de tous les sujets, la retention avait ete determinee par dosage de l'activite de l'organisme entier, a l'aide d'un analyseur d'impulsions. L'auteur analyse la retention du strontium dans le squelette et considere qu'il existe au moins trois degres de liaison entre le radiostrontium et l'os. Il etudie notamment la retention plusieurs mois apres l'infection de la dose, ainsi que le rapport entre cette retention et la dose au squelette due au {sup 90}Sr. Le memoire propose une formule permettant d'evaluer la retention corporelle d'une dose de radiostrontium d'apres la radioactivite excretee dans l'urine. (author) [Spanish] El autor examina la absorcion de estroncio del tracto gastrointestinal en relacion con el regimen alimenticio y los diferentes componentes de una dieta de pan y leche. Expone brevemente los resultados obtenidos al utilizar agentes de quelacian y de dietas ricas en calcio a fin de reducir la absorcion de estroncio. Estudia los valores de la razon estronciocalcio en diferentes partes del organismo adulto. Expone luego los resultados de experimentos realizados recientemente con sujetos normales sometidos a una dieta constante, atendiendo particularmente a las caracteristicas de la excrecion urinaria y a la retencion del (registered) {sup 85}Sr contenido en una dieta experimental. Ha calculado tambien las cantidades endogenas excretadas con las heces. Compara estos resultados con los obtenidos mediante una sola inyeccion intravenosa de estroncio radiactivo. En todos los sujetos, las cantidades retenidas se determinaron por recuento de la actividad del organismo entero con un analizador de amplitud de impulsos. El autor examina mas adelante la retencion de

  8. 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.

  9. Sorption Regularities in Behaviour of Fission-Product Elements during Filtration of their Solutions through Ground; Lois de l'Absorption des Elements Radioactifs Lors du Filtrage des Solutions a Travers les Terrains; 0417 0410 041a 041e 041d 0414 ; Leyes de la Absorcion de los Elementos Radiactivos Cuando se Filtran Soluciones a Traves de las Formaciones Geologicas

    Energy Technology Data Exchange (ETDEWEB)

    Spitsyn, V. I.; Balukova, V. D.; Gromov, V. V.; Zakharov, S. I.; Zhagin, B. P.; Spiridonov, F. M.

    1960-07-01

    cuatro meses. Despues, mediante una serie de perforaciones consecutivas, se extrajeron muestras de tierra recogidas a distintas profundidades y se analizaron para determinar su contenido de elementos radiactivos. Se pudo comprobar que la difusion de los radioisotopos alcanzaba una profundidad de diez metros por lo menos y que habia dos zonas perfectamente delimitadas en las que la radiactividad del terreno era menor: la capa superficial y el fondo de la zona de filtracion. Tambien se ha estudiado la absorcion del radioestroncio por los absorbentes naturales, especialmente por los minerales puros muy difundidos por las diversas formaciones geologicas. La presencia de iones de calcio, incluso en pequena cantidad, reduce considerablemente el grado de absorcion del radioestroncio. Sin embargo, segun su composicion -siempre que las demas condiciones sean iguales - otras sustancias pueden absorber el estroncio en cantidades mas elevadas que el calcio. Verificando in situ la absorcion y la migracion del radioestroncio se ha podido comprobar que la filtracion de las soluciones radiactivas puede revestir dos formas diferentes. En el primer caso, si las soluciones se vierten en terrenos que resisten a la accion de las corrientes de agua, el radioestroncio queda retenido por las rocas. En el segundo caso, cuando los elementos radiactivos penetran directamente en las capas acuiferas, el radioestroncio es arrastrado por las corrientes subterraneas y penetra tambien en las rocas, en las que su migracion se combina con un proceso de absorcion y desorcion. (author) [Russian] Ispol'zuja process ustanovivshejsja fil'tracii, bylo provedeno issledovanie sorbcii radiojelementov v prirodnyh uslovijah. S momenta ustanovlenija fil'tracii v rastvor vvodilis' radiojelementy, i process prodolzhalsja v techenie 4h mesjacev. Zatem posredstvom burenija otbiralis' proby grunta s razlichnyh glubin i analizirovalis' na soderzhanie radiojelementov. Rasprostranenie radioizotopov nabljudalos' do glubiny ne

  10. Considerations over the effects caused by a heat recovery system for exhaust gases, adapted to gas turbines originally designed for the operation in a simple cycle; Consideraciones sobre los efectos causados por un sistema de recuperacion de calor de gases de escape, adaptado a turbinas de gas disenadas originalmente para operar bajo un ciclo simple

    Energy Technology Data Exchange (ETDEWEB)

    Cuesta Escobar, Cesar A [Instituto Mexicano del Petroleo, Mexico, D. F. (Mexico)

    1994-12-31

    This article sets out the considerations on what a heat recovery system from exhaust gases, to already installed and in operation gas turbines, and that were not originally designed to operate with this system, can cause. The potential effects are set forth on the control systems, on the combustion chambers, and in the gas turbine blades, utilized for natural gas pumping or power generation in land installations or in offshore platforms in trying to adapt to them a regenerative cycle or a heating system. Observed effects, fundamentally in the flame stability loop, flow velocity, thermal intensity coefficient, air/fuel relationships and mass flow. Also are presented the consequences that primary production system would suffer, mainly due to the natural gas pumping reduction, the space availability, the fuel consumption, and the maximum amount of heat susceptible to be recovered, comparing the requirements of this in the system. [Espanol] En este articulo se plantean las consideraciones sobre lo que puede provocar un sistema de recuperacion de calor de gases de escape adaptado a turbinas de gas ya instaladas, operando y que no fueron disenadas originalmente para operar con este sistema. Se plantean los probables efectos en los sistemas de control, en las camaras de combustion y en los empaletados de las turbinas de gas usadas para bombeo de gas natural o generacion electrica en instalaciones de tierra o plataformas marinas, al tratar de adaptarseles un ciclo regenerativo o un sistema para calentamiento. Efectos observados, fundamentalmente, en el LOOP de estabilidad de flama, velocidad del flujo, coeficiente de intensidad termica, relaciones aire-combustible y flujo masico. Tambien se presentan las consecuencias que sufriria el sistema primario de produccion debido, principalmente, a la reduccion del bombeo de gas natural, a la disponibilidad de espacio, al consumo de combustible y a la cantidad maxima de calor susceptible de recuperarse, comparada con los

  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. 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.

  13. 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.

  14. 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.

  15. 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

  16. Measurement of uranium concentration by molecular absorption spectrophotometry by means optical fibers; Medicion continua de concentracion de uranio por espectrofotometria de absorcion molecular mediante fibras opticas

    Energy Technology Data Exchange (ETDEWEB)

    Gauna, Alberto C.; Pascale, Ariel A. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina). Centro Atomico Ezeiza. Agencia Minipost

    1996-07-01

    An on-line method for measuring the concentration of uranium in uranyl nitrate-nitric acid aqueous solutions is described. The method is based on molecular absorption spectrophotometry with transmission of light by means of optical fibers. It is ideally suited for control and processes development applications. (author)

  17. Absorption-desorption of drugs in porous polymers obtained by plasma; Absorcion-desorcion de farmacos en polimeros porosos obtenidos por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez T, M.

    2016-07-01

    A study about drug absorption and release in plasma polymers is presented in this work, these materials can be used as implants in the human body. In these applications the polymer should be biocompatible and/or biodegradable. Poly pyrroles and poly allylamine s synthesized by plasma have amine groups in their structure which makes them biocompatible with potential as drug carriers. In this function, the polymers were lyophilized to induce pores where the drug can be hosted. Drug-polymer mixtures with 1:10 ratio were prepared. The mixture morphology was studied by Scanning Electron Microscopy while their chemical structure was studied by Infrared Spectroscopy and X-ray Photoelectron Spectroscopy. Two models were studied to assess drug release, dynamic and static, in two solutions: water and Krebs Ringer (Kr) using the UV characteristic absorbance of each drug. In the static model release, 5 mg of the mixture were placed in 10 ml of solution. In the dynamic model, the release was performed with 5 mg of the mixture in 10 ml of solution, 1.5 ml of release medium was removed for UV analysis and replaced with an equal volume of fresh medium. The results indicate that the morphology of the polymers was modified with the lyophilization, in Poly pyrrole pores were induced with diameter in the range of 0.7 to 19 μm, while in Polyallyl amine the surface changed from smooth to rough. Drugs were absorbed in Poly pyrrole by filling the pores first and then coating the polymer with a drug layer. In Poly allylamine the drugs adhered to the polymer surface. Analyzing the atomic orbitals of the mixtures, it was found that the drugs interacted with the polymer. The most affected orbital was S2p, whose separation between 1/2 and 3/2 sub orbitals increased from 0.9 eV in Dapsone and Heparin to 4 eV in the mixtures, where the oxidation state changed from valence 6 to 6 and 2 in the mixtures. This suggests physicochemical interaction between drug and polymer. The drugs were released from the polymers in a higher concentration in the Kr solution than in water due to the ionic forces of the salt content in the Kr solution. Two linear trends were found, first the drug coated the polymer and later the drug within the pores went into the solution. After the drug is released in water, the polymers returned acquired morphology similar to that obtained with the lyophilization. After the release in Kr, the salts forming the Kr solution agglomerate on the polymer surface. (Author)

  18. Emission and absorption of light in poly pyrrole synthesized by plasma; Emision y absorcion de luz en polipirrol sintetizado por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, M.A.; Colin, E.; Olayo, M.G.; Cruz, G.J.; Ordonez, E. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Benavides, R. [Departamento de Procesos de Transformacion, CIQA, Blvd. Enrique Reyna 140, Saltillo, Coahuila (Mexico); Morales, J.; Olayo, R. [UAM-I, Apdo. Postal 55-534, Iztapalapa, D.F. (Mexico)]. e-mail: gcc@nuclear.inin.mx

    2007-07-01

    The poly pyrrole structure (PPy) consists of heterocyclic rings with conjugation that it depends on the intensity of the electric field applied during the synthesis, and its luminescence is related with the {pi}-{pi}{sup *} transitions of that conjugation. To irradiate with light of different wavelengths, the results indicate that the polymer absorbs in the interval from 290 to 700 nm and it emits between 450 and 470 nm. The basal conductivity of the polymers, without electromagnetic excitation, it was measured in 10{sup -15} S/cm, however, to interact with visible light it is increased approximately 10 times and when excite with UV light it is increased up to 3 magnitude orders. (Author)

  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. 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.

  1. Caloric vestibular stimulation in aphasic syndrome

    Directory of Open Access Journals (Sweden)

    David eWilkinson

    2013-12-01

    Full Text Available Caloric vestibular stimulation (CVS is commonly used to diagnose brainstem disorder but its therapeutic application is much less established. Based on the finding that CVS increases blood flow to brain structures associated with language and communication, we assessed whether the procedure has potential to relieve symptoms of post-stroke aphasia. Three participants, each presenting with chronic, unilateral lesions to the left hemisphere, were administered daily CVS for 4 consecutive weeks. Relative to their pre-treatment baseline scores, two of the three participants showed significant improvement on both picture and responsive naming at immediate and one-week follow-up. One of these participants also showed improved sentence repetition, and another showed improved auditory word discrimination. No adverse reactions were reported. These data provide the first, albeit tentative, evidence that CVS may relieve expressive and receptive symptoms of aphasia. A larger, sham-controlled study is now needed to further assess efficacy.

  2. Unix version of CALOR89 for calorimeter applications

    International Nuclear Information System (INIS)

    Handler, T.

    1992-01-01

    CALOR89 is a system of coupled Monte Carlo particle transport computer codes which has been successfully employed for the estimation of calorimeter parameters in High Energy Physics. In the past CALOR89 has been running on various IBM machines and on CRAY X-MP at Lawrence Livermore Lab. These machines had non-unix operating systems. In this report we present a UNIX version of CALOR89, which is especially suited for the UNIX work stations. Moreover CALOR89 is also been supplemented with two new program packages which makes it more user friendly. CALPREP is a program for the preparation of the input files for CALOR89 in general geometry and ANALYZ is an analysis package to extract the final results from CALOR89 relevant to calorimeters. This report also provides two script files LCALOR and PCALOR. LCALOR runs CALOR89 sequences of programs and EGS4 for a given configuration sequentially on a single processor and PCALOR concurrently on a multiprocessor unix workstation

  3. Análise de algumas variáveis fisiológicas para avaliação do grau de adaptação de ovinos submetidos ao estresse por calor Analysis of some physiological variables for the evaluation of the degree of adaptation in sheep submitted to heat stress

    Directory of Open Access Journals (Sweden)

    Josiane Maria Cardoso Starling

    2002-09-01

    Full Text Available Investigaram-se a temperatura retal, a freqüência respiratória e a taxa de evaporação total de ovinos Corriedale sob três temperaturas ambientes, visando uma melhor compreensão dos mecanismos de termorregulação desses animais. Inicialmente, 21 animais adultos foram alojados em câmara climática à temperatura de 45ºC, e pressão parcial de vapor (PV variável, registrando-se a freqüência respiratória (FR e a temperatura retal (TR. Baseando-se na FR e TR, foram selecionados 10 animais, cinco com os valores mais baixos, assumindo-os como mais adaptados ao calor (grupo 1 e cinco com valores mais altos, assumindo-os como menos adaptados (grupo 2. Os animais selecionados foram mantidos em câmara climática, onde mediram-se novamente TR, FR e taxa de evaporacão total (TET, sob 20, 30 e 40ºC de temperatura do ar e PV variável. Não houve diferença estatística entre os grupos classificados, para todas as variáveis medidas. Concluiu-se que a utilização das variáveis fisiológicas TR e FR como parâmetros únicos para a seleção destes animais não é suficiente para avaliar o grau de adaptação a temperaturas elevadas.It was investigated the rectal temperature, respiratory frequency and total evaporative heat loss rate in Corriedale sheep under three air temperatures, aiming a better comprehension of thermoregulation mechanisms of these animals. Initially, 21 adult animals were housed in climatic chamber under 45ºC and variable air humidity (PV, recording the respiratory frequency (FR and rectal temperature (TR. Basing on the FR and TR, it was selected 10 animals, five of the lowest values, assuming as being the best heat adapted (group 1 and five of the highest values, assuming as the worst heat adapted (group 2. The selected animals were maintained in climatic chamber, where it was measured again TR, FR and total evaporation rate (TET, under 20, 30 and 40ºC of air temperature and variable PV. There was no statistical

  4. 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

    Full Text Available O presente artigo questiona o papel do calor como um fator de risco adicional para o acidente que vitimou Ayrton Senna. O automobilismo de competição constitui um desafio biológico, uma situação estressante do ponto de vista mental e físico. A manutenção da performance depende da disponibilidade de carboidratos e oxigênio, hidratação adequada e temperatura interna constante entre 37 e 38 graus centígrados. A dissipação do calor produzido pelo metabolismo ocorre através do aumento do fluxo de sangue para pele e produção de suor e manter a temperatura cerebral constante se constitui num problema permanente. Verificou-se experimentalmente que a energia necessária para dirigir um automóvel de corrida é comparável a um esporte como o voleibol. Durante uma corrida, o indivíduo está exposto a um microambiente quente na cabina, que pode atingir 50ºC, gerado por fontes de calor mecânicas e ambientais. O bloqueio da evaporação do suor pelo macacão resulta em umidade e desconforto pessoal, o que implica maior esforço mental para dirigir o carro. As medidas contra o calor começam antes da corrida, cuidando-se do estado nutricional, da hidratação e principalmente do condicionamento físico através de exercícios aeróbios regulares e adequados, que permitem aumentar a capacidade de trabalho e a tolerância ao calor, o que resulta em menor fadiga durante a corrida. Outro procedimento importante deveria ser a aclimatação prévia dos pilotos aos ambientes quentes e úmidos. Deve-se fazer o possível para reduzir o aquecimento do veículo e respeitar o sistema de bandeiras de advertência para os riscos de hipertermia. Em conclusão, embora Ayrton Senna fosse um indivíduo com maior risco de desenvolver hipertermia, independentemente de outras causas, não parece ter havido tempo de corrida suficiente para haver produção de calor metabólico capaz de aumentar excessivamente a temperatura interna do piloto nas condi

  5. 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.

  6. Current status of the second generation of parabolic trough solar concentrator for heat generation process designed at the IIE; Estado actual de la segunda generacion del concentrador solar de canal parabolico para generacion de calor de proceso disenado en el IIE

    Energy Technology Data Exchange (ETDEWEB)

    Ramos Berumen, Carlos; Ramirez Benitez, Juan Rafael; Beltran Adan, Jose [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: cramos@iie.org.mx; rramirez@iie.org.mx; jose.beltran@iie.org.mx

    2010-11-15

    The transformation industry normally uses thermal energy within its process, it obtains this energy burning fossils fuel, a new option is to use new technologies like the thermal solar technology like the parabolic trough, this is a long parabolic mirror used to reflect the sunlight and focused on an absorber tube with a heat-conducting fluid inside. The Instituto de Investigaciones Electricas (IIE) developed a prototype of parabolic trough that is operating in different industries, in this article are showing some improvements to the design, giving like result the second generation of the prototype of parabolic trough of the IIE. [Spanish] La industria de la transformacion normalmente utiliza energia termica dentro de su proceso, los medios convencionales para obtener esta energia es el quemar combustibles fosiles, una opcion que aplica nuevas tecnologias es el uso de la tecnologia termosolar a concentracion que le permitira a la industria utilizar el sol como fuente de energia primaria. El uso de esta tecnologia permitira a las empresas generar calor de proceso sin contaminar el ambiente, lo que dara como resultado empresas competitivas y autosuficientes. Para alcanzar temperaturas utiles a estas aplicaciones se requiere concentrar la energia solar en un area mas pequena, siendo la tecnologia mas extendida la de canal parabolico, el principio de operacion de esta tecnologia es la de concentrar la radiacion solar en el eje receptor preparado con una pintura especial para una mejor absorcion del calor y una cubierta de vidrio para evitar perdidas termicas, dentro del tubo circula un fluido caloportador el cual lleva el calor util hacia el proceso. El Instituto de Investigaciones Electricas (IIE) desarrollo un prototipo de canal parabolico, actualmente estan operando en diferentes industrias, resultado de estas aplicaciones se llevo a cabo una evaluacion del prototipo, se detectaron algunos puntos de mejoras al diseno, los cuales se exponen en este articulo, dando

  7. Caloric utilization of sorbitol and isomalt in the rat

    International Nuclear Information System (INIS)

    Figdor, S.K.; Allingham, R.P.; Kita, D.A.; Hobbs, D.C.

    1987-01-01

    Sorbitol and isomalt are modified saccharides used to substitute for the physical properties of sucrose in various prepared foods. The merits of the various methods for determining caloric availability were reviewed. Balance and growth curve methods are inaccurate and inappropriate for determination of the caloric availability of these substances when present in diets at low concentrations, whereas the radiolabel disposition method is a direct and precise measure of utilization. Accordingly, the authors administered uniformly 14 C-labeled material to rats and collected excreta and expired air. The appearance of about half of the label in CO 2 indicated that, by comparison with labeled glucose, about 80% of the orally administered sorbitol and isomalt was calorically available to the rat. The high caloric availabilities of these materials were confirmed by the appearance in feces of only 14 and 12% of the administered label from sorbitol and isomalt, respectively

  8. 21 CFR 874.1800 - Air or water caloric stimulator.

    Science.gov (United States)

    2010-04-01

    ... vestibular function testing of a patient's body balance system. The vestibular stimulation of the... stimulator. (a) Identification. An air or water caloric stimulator is a device that delivers a stream of air...

  9. The minimal ice water caloric test compared with established vestibular caloric test procedures.

    Science.gov (United States)

    Schmäl, Frank; Lübben, Björn; Weiberg, Kerstin; Stoll, Wolfgang

    2005-01-01

    Caloric testing of the vestibular labyrinth is usually performed by classical caloric test procedures (CCTP) using water warmed to 30 degrees C and 44 degrees C. Ice water irrigation (4 degrees C) is usually not performed, although it might be useful as a bedside test. To verify the validity of the Minimal Ice Water Caloric Test (MIWCT), comparative video-oculographic investigations were performed in 22 healthy subjects using ice water (0.5 ml, 1.0 ml, 2 ml), CCTP, and cold air (27 degrees C). Frequency, amplitude, slow phase velocity (SPV), the onset, and the duration of nystagmus were documented. After addition of three ice cubes, the temperature of conventional tap water (16 degrees C) fell within 13 min to 4 degrees C. In pessimum position the subjects demonstrated no nystagmus response. Compared to CCTP, MIWCT was associated with a significantly later onset of nystagmus and a significant prolongation of the nystagmus reaction. In contrast to air stimulation (27 degrees C), a significant Spearman's correlation was noted between MIWCT (1 and 2 ml) and established CCTP in respect of essential nystagmus parameters (frequency, amplitude and SPV). Furthermore, MIWCT (0.5 and 1 ml) showed a higher sensitivity and specificity with regard to the detection of canal paresis based on Jongkees' formula compared to stimulation with air 27 degrees C. Thus, MIWCT appears to be a suitable procedure for bedside investigation of vestibular function outside the vestibular laboratory, e.g. in a hospital ward, where bedridden patients with vertigo occasionally require vestibular testing.

  10. 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.

  11. 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.

  12. 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,...

  13. 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...

  14. Changes of ampulla pressure in the semicircular canal of pigeons by caloric stimulation

    Science.gov (United States)

    Wada, Yoshiro; Suzuki, Hiroyuki; Watanabe, Satoru

    Still now several hypotheses about the mechanisms of the caloric nystagmus have been in conclusive. In this study we confirmed the convection effect and the volume change effect of the endolymph in horizontal semicircular canal following the caloric stimulation using pigeons ( Columba livia). Although the direction of the caloric nystagmus depended on the head position and the stimulus site of calorization, the caloric nystagmus disappeared after plugging of horizontal semicircular canal. On the other hand, the ampulla pressure increased by cold calorization and decreased by hot calorization and these pressure changes had no relation to the head position. These results show that the main role of the mechanisms of the caloric nystagmus under 1G is the convection effect but the volume change effect may act on the caloric nystagmus not only under 1G but also under microgravity.

  15. Measuring caloric response: comparison of different analysis techniques.

    Science.gov (United States)

    Mallinson, A I; Longridge, N S; Pace-Asciak, P; Ngo, R

    2010-01-01

    Electronystagmography (ENG) testing has been supplanted by newer techniques of measuring eye movement with infrared cameras (VNG). Most techniques of quantifying caloric induced nystagmus measure the slow phase velocity in some manner. Although our analysis is carried out by very experienced assessors, some systems have computer algorithms that have been "taught" to locate and quantify maximum responses. We wondered what differences in measurement might show up when measuring calorics using different techniques and systems, the relevance of this being that if there was a change in slow phase velocity between ENG and VNG testing when measuring caloric response, then normative data would have to be changed. There are also some subjective but important aspects of ENG interpretation which comment on the nature of the response (e.g. responses which might be "sporadic" or "scant"). Our experiment compared caloric responses in 100 patients analyzed four different ways. Each caloric was analyzed by our old ENG system, our new VNG system, an inexperienced assessor and the computer algorithm, and data was compared. All four systems made similar measurements but our inexperienced assessor failed to recognize responses as sporadic or scant, and we feel this is a limitation to be kept in mind in the rural setting, as it is an important aspect of assessment in complex patients. Assessment of complex VNGs should be left to an experienced assessor.

  16. Isla de calor y ocupación espacial urbana en San Juan, Argentina: análisis evolutivo.
    Island heat effect and spatial urban occupancy in San Juan, Argentina: evolution analysis
    Ilha de calor e ocupação do espaço urbano em San Juán, Argentina: análise evolutiva

    OpenAIRE

    Mario Cúnsulo; Alejandra Kurbán; Alberto Papparelli

    2011-01-01

    Resumen:En este artículo se presentan resultados finales de un proyecto de investigación bianual (2009-2010), denominado Variación histórica y espacial de la isla de calor urbana en zona árida, financiado por la Universidad Nacional de San Juan, Argentina. Su objetivo principal es determinar la progresiva modificación de la isla de calor urbana en un periodo de quince años (1995-2010) y la correlación de esta con la ocupación del área urbana del Gran San Juan (GSJ), localizada en la diagonal ...

  17. Quantificação da ilha de calor de curitiba considerando aspectos de estabilidade atmosférica

    Directory of Open Access Journals (Sweden)

    Eduardo Krüger

    2015-12-01

    Full Text Available RESUMO A relação entre crescimento urbano e o surgimento de ilhas de calor urbanas, ou seja, diferenças climáticas entre a área urbana e as áreas rurais no entorno, é demonstrada por diversos autores e em diferentes regiões climáticas. Em Curitiba, a população saltou de aproximadamente 600.000 habitantes para um milhão e meio em três décadas. O objetivo do presente trabalho é propor uma metodologia de análise da ilha de calor urbana de Curitiba (25º25'40"S, 49º16'23"W, 934m acima do nível do mar. A cidade está localizada em região de clima subtropical de altitude; o monitoramento climático foi conduzido segundo uma série anual, entre dezembro de 2011 e fevereiro de 2013, utilizando um par de estações meteorológicas dentro e fora (perifericamente da mancha urbana de Curitiba. De modo a minimizar possíveis influências atmosféricas na análise, foi feita a classificação dos dias de medição por classes de estabilidade atmosférica segundo o método de Pasquill-Gifford-Turner (PGT, procedendo-se à análise para dias com maior estabilidade atmosférica. Como complemento à análise, adota-se um modelo de conforto desenvolvido para Curitiba a partir de uma extensa pesquisa de sensação e percepção térmicas em espaços abertos, de modo a verificar o efeito integrado das diversas variáveis climáticas em termos de percentuais de horas em frio, conforto e calor e suas variações dentro e fora da área urbana. Em Curitiba, a ilha de calor urbana pode ser benéfica durante o inverno, porém trazendo consequências em termos de excesso de calor em ambientes internos no verão.

  18. Emotional reaction evaluation provoked by the vestibular caloric test through physiological variables monitoring.

    Science.gov (United States)

    Barona-de-Guzmán, Rafael; Krstulovic-Roa, Claudio; Donderis-Malea, Elena; Barona-Lleó, Luz

    2018-03-08

    The emotional evaluation of the causes of vertigo is made using the clinical records and several subjective questionnaires. The aim of the present study is to evaluate the emotional response objectively, in normal subjects, during an induced vertigo crisis. A caloric vestibular test with cold water was performed on 30 healthy subjects. The following physiological parameters were monitored during the 60seconds prior to and the 60seconds after the stimulation: Skin Conductivity, Peripheral Pulse Volume, Body Temperature, Muscle Contraction, Heart Rate, and Respiratory Rate. The maximum angular speed of the nystagmus slow phase at each stimulation was assessed. Skin conductance presented a statistically significant increase during the vertigo crisis in relation to the prior period while the peripheral pulse volume presented a statistically significant decrease. There was no relationship between the slow phase of the provoked nystagmus angular speed and skin conductance and peripheral pulse volume changes. The decrease in peripheral pulse volume was significantly higher in the second vertigo crisis. Skin conductance and peripheral pulse volume changed significantly during a vertigo crisis. There was no relation between the provoked vertiginous crisis intensity and the changes produced in those variables. The stress generated by the caloric stimulation is higher in the second crisis, when the subject has experience of the vertigo caused by the stimulation. Copyright © 2018 Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. Publicado por Elsevier España, S.L.U. All rights reserved.

  19. 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.

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

    OpenAIRE

    Mª Salud Alonso García; Mª del Rosario Fidalgo Martínez; José Luis Labajo Salazar

    2004-01-01

    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 situ...

  1. EL CALOR DE LA TEORÍA

    Directory of Open Access Journals (Sweden)

    Fernando J. García Selgas

    2015-01-01

    Full Text Available Este trabajo es una reflexión crítica sobre la apuesta metateórica que Alfonso Pérez Agote hacepor lo que él denomina “teoría caliente” (TC. Empiezo analizando qué entiende por TC, cómoargumenta su preferencia por ella frente a la “teoría fría” y cómo la aplica de manera efectiva.Tras recordar que esta tesis resulta un salto en el vacío respecto a planteamientos previos mejorasentados, paso a cuestionar algunos de sus supuestos e implicaciones. Todo ello, más el hechode que la practica sociológica del propio Alfonso parece incumplir su propuesta, viene a mostrarque la tesis de la TC resulta ser una excusa innecesaria y perjudicial para quien, queriendoceñirse a la investigación empírica, no puede evitar tomar partido en los debates teóricos y ve larealidad social como una realidad predefinida.

  2. Metabolic effects of intermittent access to caloric or non-caloric sweetened solutions in mice fed a high-caloric diet.

    Science.gov (United States)

    Soto, Marion; Chaumontet, Catherine; Even, Patrick C; Azzout-Marniche, Dalila; Tomé, Daniel; Fromentin, Gilles

    2017-06-01

    Human consumption of obesogenic diets and soft drinks, sweetened with different molecules, is increasing worldwide, and increases the risk of metabolic diseases. We hypothesized that the chronic consumption of caloric (sucrose, high-fructose corn syrup (HFCS), maltodextrin) and non-caloric (sucralose) solutions under 2-hour intermittent access, alongside the consumption of a high-fat high-sucrose diet, would result in differential obesity-associated metabolic abnormalities in mice. Male C57BL/6 mice had ad libitum access to an HFHS diet and to water (water control group). In addition, some mice had access, 2h/day, 5days/week (randomly chosen) for 12weeks, to different solutions: i) a sucrose solution (2.1kJ/ml), ii) an HFCS solution (2.1kJ/ml), iii) a maltodextrin solution (2.1kJ/ml) and a sucralose solution (60mM) (n=15/group). Despite no changes in total caloric intake, 2h-intermittent access to the sucrose, HFCS or maltodextrin solutions led to increased body weight and accumulation of lipids in the liver when compared to the group consuming water only. The HFCS and sucrose solutions induced a higher fat mass in various fat depots, glucose intolerance, increased glucose oxidation at the expense of lipid oxidation, and a lower hypothalamic expression of NPY in the fasted state. HFCS also reduced proopiomelanocortin expression in the hypothalamus. 2h-intermittent access to sucralose did not result in significant changes in body composition, but caused a stronger expression of CART in the hypothalamus. Finally, sucrose intake showed a trend to increase the expression of various receptors in the nucleus accumbens, linked to dopamine, opioid and endocannabinoid signaling. In conclusion, 2h-intermittent access to caloric solutions (especially those sweetened with sucrose and HFCS), but not sucralose, resulted in adverse metabolic consequences in high-fat high-sucrose-fed mice. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Medida de calor específico e lei de resfriamento de Newton: um refinamento na análise dos dados experimentais

    Directory of Open Access Journals (Sweden)

    Silva Wilton Pereira da

    2003-01-01

    Full Text Available Uma das técnicas para a determinação do calor específico de sólidos e líquidos dispensa o uso de um calorímetro e utiliza a lei de resfriamento de Newton na análise dos dados experimentais. O sucesso desta técnica pressupõe que seja possível determinar, com pequenas incertezas, as temperaturas do sistema imediatamente antes e imediatamente depois das transferências internas de calor devido à imersão do corpo (dujo calor específico se deseja medir em um recipiente contendo água quente. Neste artigo é proposto um refinamento desta técnica utilizando-se dois ajustes de curvas para a função que descreve a lei de resfriamento, com pequenas extrapolações, para de determinar essas temperaturas e também as suas incertezas. Isto possibilita determinar não só o valor médio do calor específico, mas também a incerteza deste valor médio, por propagação de erros. O ajuste da própria função que descreve a lei de resfriamento aos dados possibilitou a comparação imediata dos parâmetros obtidos experimentalmente com aqueles previstos pela teoria, e há uma grande concerdânciaentre eles. A aplicaçãodeste refinamento na determinação do calor específico do alumínio indica que tal procedimento é eficaz mesmo quando se trabalha com instrumentos de baixo custo, voltados para o ensino.

  4. Herdabilidade da necessidade de calor para a antese e brotação em pessegueiro Heritability of heat requirement for blooming and leafing in peach

    Directory of Open Access Journals (Sweden)

    Idemir Citadin

    2003-04-01

    Full Text Available A herdabilidade da necessidade de calor para antese e brotação em pessegueiro [Prunus persica (L. Batsch] foi estudada em ramos de 16 cultivares e seleções de baixa, média e alta necessidade de calor e 11 progênies oriundas de hibridações entre elas. Os ramos foram submetidos, previamente, a 2 ºC por 500 horas para satisfazer a necessidade de frio. O valor estimado da herdabilidade média para a necessidade de calor em gemas florais foi de 45% e 57%, em 1999 e 2000, respectivamente. Para gemas vegetativas, o valor estimado foi de 30%, em 1999. 'BR-1', 'Barbosa', 'Chula', 'Chinoca' e 'Eldorado' transmitem melhor o caráter necessidade de calor para as progênies do que os demais genótipos estudados. Os registros observados suportam um modelo de herança quantitativa com genes de maior efeito para menor necessidade de calor. A seleção de indivíduos com maior necessidade de calor para floração tende a retardar a floração sem, contudo, retardar com a mesma intensidade a época de brotação.Heritability of heat requirement for blooming and leafing was investigated in peach [Prunus persica (L. Batsch], using artificially chilled excised shoots of 11 populations and 16 parental clones of low, intermediate and high heat requirement. The estimated values of broad sense heritability of heat requirement in flower buds were 45% and 57%, in 1999 and 2000, respectively. In leaf buds, the heritability was 30% in 1999. 'BR-1', 'Barbosa', 'Chula', 'Chinoca', and 'Eldorado' can transmit the heat requirement character better to offspring than the others studied genotypes. The data support a model for quantitative inheritance with partial dominance for low heat requirement. Seedling selection for high heat requirement delay blooming more than leafing.

  5. Caloric requirement of the critically ill septic patient

    International Nuclear Information System (INIS)

    Shizgal, H.M.; Martin, M.F.

    1988-01-01

    The caloric requirement of the critically ill septic patient was determined by measuring body composition, by multiple isotope dilution, before and at 2-wk intervals while receiving total parenteral nutrition (TPN) in 86 septic and 57 nonseptic malnourished patients. All patients received a TPN solution containing 25% dextrose and 2.75% crystalline amino acids. The body composition of the nonseptic patients, who received 51.9 +/- 1.5 kcal/kg.day, improved significantly, while that of the septic patients, receiving 46.8 +/- 1.1 kcal/kg.day was only maintained. The relationship between caloric intake and the restoration of a malnourished body cell mass (BCM) was determined for each group by correlating, using multiple linear regression, the mean daily change in the BCM with the caloric intake and the nutritional state, as determined by body composition. According to the resultant regressions, an intake of 35.1 and 50.7 kcal/kg.day was required to maintain the BCM of the septic and nonseptic patients, respectively. To restore a depleted BCM, caloric intakes in excess of this amount are required

  6. 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.

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

    African Journals Online (AJOL)

    Studies have shown that dietary caloric restriction (CR) without malnutrition can increase longevity. This study aims to evaluate the protective effects of CR on oxidative stress, lipid peroxidation and inflammatory cytokines in the kidney of streptozotocin-induced diabetic rats. Forty 12-week old male Wistar rats, weighing ...

  8. Phenomenological approach to the caloric theory of heat

    Czech Academy of Sciences Publication Activity Database

    Mareš, Jiří J.; Hubík, Pavel; Šesták, Jaroslav; Špička, Václav; Krištofik, Jozef; Stávek, J.

    2008-01-01

    Roč. 474, č. 1-2 (2008), s. 16-24 ISSN 0040-6031 R&D Projects: GA AV ČR IAA1010404; GA AV ČR IAA100100639 Institutional research plan: CEZ:AV0Z10100521 Keywords : caloric * entropy * heat * thermodynamics * heat engines Subject RIV: BJ - Thermodynamics Impact factor: 1.659, year: 2008

  9. Quantifying the association between obesity, automobile travel, and caloric intake.

    Science.gov (United States)

    Behzad, Banafsheh; King, Douglas M; Jacobson, Sheldon H

    2013-02-01

    The objective of this study is to assess the association between average adult body mass index (BMI), automobile travel, and caloric intake in the US in order to predict future trends of adult obesity. Annual BMI data (1984-2010) from the Behavioral Risk Factor Surveillance System (BRFSS), vehicle miles traveled data (1970-2009) from the Federal Highway Administration, licensed drivers data (1970-2009) from the Federal Highway Administration, and adult average daily caloric intake data (1970-2009) from the US Department of Agriculture were collected. A statistical model is proposed to capture multicollinearity across the independent variables. The proposed statistical model provides an estimate of changes in the average adult BMI associated with changes in automobile travel and caloric intake. According to this model, reducing daily automobile travel by one mile per driver would be associated with a 0.21 kg/m(2) reduction in the national average BMI after six years. Reducing daily caloric intake by 100 calories per person would be associated with a 0.16 kg/m(2) reduction in the national average BMI after three years. Making small changes in travel or diet choices may lead to comparable obesity interventions, implying that travel-based interventions may be as effective as dietary interventions. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Some factors influencing the absorption, retention and elimination of ruthenium; Facteurs agissant sur l'absorption, la retention et l'elimination du ruthenium; Nekotorye faktory, vliyakshchie na vsasyvanie, zaderzhku i vydelenie ruteniya; Factores que influyen sobre la absorcion, retencion y eliminacion de rutenio

    Energy Technology Data Exchange (ETDEWEB)

    Bruce, R. S. [Radiobiological Research Council, Medical Research Council, Harwell (United Kingdom)

    1963-02-15

    presencia de portador y con el dioxido en forma de particulas, mientras que si esta en estado coloidal y exento de portador, la absorcion es similar a la que se produce al administrar el cloruro (3 a 5%). Los nitratodenvactos del mtrosilrutenio se pueden absorber en mayor grado aun (los conejos absorben en promedio el 13%). Cuando las ratas no se encuentran en ayunas, la absorcion es total a la hora de administrar una dosis por via oral. Este periodo de absorcion tan corto se podria explicar por la velocidad de vaciado del estomago y la combinacion del rutenio con ciertas sustancias contenidas en el intestino. Si se mantienen las ratas en ayunas la noche antes de administrar el rutenio; el grado de absorcion se triplica y el proceso continua durante bastante tiempo. Contrariamente a otros compuestos ya ensayados los nitratoderivados del nitrosilrutenio reaccionan con las paredes de la parte superior del intestino delgado, que son capaces de retener durante varias horas hasta el 20% de una dosis orai. El estado quimico del rutenio ejerce influencia sobre el grado de absorcion, pero no afecta mayormente a la distribucion ulterior del elemento. Durante las primeras 24 horas se excreta por la orina aproximadamente la mitad del rutenio absorbido. Al cabo de un mes, quedan todavia retenidos, con un periodo biologico largo, del 5 al 20{sup o}/ode la fraccion absorbida. El rutenio se distribuye por todo el organismo y las concentraciones en los diversos organos rara vez difieren en un factor superior a cinco, aunque la distribucion en un solo tejido no sea necesariamente homogenea. La concentracion en los rinones, que constituyen la via principal de eliminacion, es elevada. El estudio del comportamiento del rutenio en el suero sanguineo ayuda a explicar los procesos que gobiernan su distribution y retencion. Cuando el rutenio se mezcla in vitro con ei suero una parte queda firmemente ligada a las proteinas en tanto que el resto permanece libre. El rutenio libre se puede detectar en

  11. 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.

  12. Factors contributing to the nuclear caloric curve aspect

    International Nuclear Information System (INIS)

    Raduta, Al.H.; Raduta, Ad.R.

    1999-01-01

    After the first experimental evaluation of the nuclear caloric curve a large amount of theoretical work was concentrated to reproduce the transition-like plateau of the caloric curve from 5 MeV temperature. Both dynamical and statistical models have been employed in order to deduce the excitation energy dependence of the temperature of the equilibrated nuclear systems formed in violent heavy ion collisions. For describing such kind of systems a microcanonical model fully obeying the involved physical constrains seems to be the most appropriate option. However, the currently used statistical multifragmentation models (SMM and MMMC ) are not fully satisfying the microcanonical rules. For these reasons the nuclear caloric curve is studied in the present work from the point of view of a sharp microcanonical model. In this respect a detailed analysis concerning the contribution of the various energetic degrees of freedom (binding, Coulomb repulsive and internal excitation) to the curve aspect is performed. The method adopted here consists in suppressing each of the above-mentioned degrees of freedom once at a time keeping the rest of the system parameters unchanged. The Coulomb repulsive (V) and excitation (ε) degrees of freedom are suppressed by fixing the respective energies to zero. The binding degree of freedom (B) is 'suppressed' by fixing it to the constant value of - 8.5 MeV/nucleon for all fragments. The effect of the correlation between the Coulomb repulsive and the excitation degrees of freedom on the caloric curve aspect is also studied. The resulting caloric curves are denoted T -V , T -ε , T -B , T -Vε . One may observe that the suppression of the excitation degree of freedom has the effect of lifting and diminishing the plateau and the suppression of the Coulomb degree of freedom is lowering the plateau and almost washes-out the plateau-like region. The spectacular effect concerns the complementary moves T -Vε and - B: While the Vε couple suppression

  13. SIMULACION DE LA PUESTA EN MARCHA DE UN REACTOR DE BIOPELÍCULA ANAEROBIA TIPO INTERCAMBIADOR DE CALOR

    Directory of Open Access Journals (Sweden)

    Ramiro Escalera Vásquez

    2009-01-01

    Full Text Available Se ha desarrollado un  modelo de reactor que considera la separación de fases microbianas dentro de un reactor anaerobio tipo intercambiador de calor, donde las bacterias acidogénicas predominan en la masa líquida recirculante y las heteroacetogénicas y metanogénicas lo hacen en la biopelícula adherida a las paredes. El modelo considera también las resistencias difusionales a la transferencia de masa ocasionadas por la capa laminar y la biopelícula. También se consideran las reacciones paralelas y consecutivas propias de la degradación anaerobia de compuestos orgánicos fácilmente biodegradables, por ejemplo, residuos industriales de altas concentraciones de carbohidratos. El modelo de reactor y las ecuaciones pseudo-analíticas para la estimación de los factores de efectividad, desarrolladas para otro tipo de bioreactores anaerobios tales como lechos empacados y fluidizados, pueden utilizarse para estimar la eficacia y evaluar el funcionamiento de un Reactor de Biopelícula Anaerobia tipo Intercambiador de Calor (RBAIC . En este trabajo se ha verificado que los resultados del modelo concuerdan con los resultados experimentales de la eficacia y funcionamiento del RBAIC, dentro del periodo de puesta en marcha.

  14. Análise da transferência de calor de fluidos térmicos aditivado com etilenoglicol e polímeros

    OpenAIRE

    Santana, Rony Oliveira de

    2016-01-01

    Um sistema de arrefecimento é usado para manter a temperatura ideal de funcionamento e evitar sobreaquecimento, através de um fluido térmico também chamado fluido de arrefecimento e um trocador de calor. Os fluidos de arrefecimento são normalmente compostos por uma solução de água e um aditivo, além de aditivos inibidores de corrosão e corantes. O etilenoglicol é um tipo de álcool amplamente utilizado como aditivo por ser totalmente solúvel, com baixa ou nenhuma atividade corrosiva e quimicam...

  15. 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, S.; Ciapaite, J.; Wolters, J.C.; van Riel, N.A.; Nicolay, K.; Prompers, J.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

  16. 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

  17. 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.

  18. Estimativa do fluxo de calor latente pelo balanço de energia em cultivo protegido de pimentão

    Directory of Open Access Journals (Sweden)

    Cunha Antonio Ribeiro da

    2002-01-01

    Full Text Available O objetivo deste trabalho foi caracterizar e relacionar a radiação líquida com o calor latente equivalente, em mm de água, nos cultivos protegido e de campo, na cultura de pimentão. O experimento foi feito em Botucatu, SP. A estimativa do fluxo de calor latente foi feita pelo método do balanço de energia, por meio da razão de Bowen. Foram feitas medidas instantâneas da radiação líquida (Rn, dos fluxos convectivos de calor latente (LE e sensível (H, do fluxo de calor no solo (G, e dos gradientes psicrométricos sobre a cultura. O cultivo protegido, apesar de receber menor quantidade de radiação solar global, foi mais eficiente na conversão da radiação líquida disponível em matéria seca total e na produtividade de frutos. No balanço de energia, o cultivo protegido apresentou razões G/Rn e LE/Rn inferiores e H/Rn superior, com um fluxo de calor latente, equivalente em milímetros, 45,43% menor que no cultivo no campo. Apresentou, ainda, menor quantidade de radiação líquida disponível e menores perdas de energia, mostrando-se mais eficiente no uso da água.

  19. Construcción de un calorímetro isoperibolico de inmersión de precisión

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo G.

    2010-07-01

    Full Text Available Se diseña y construye un calorímetro isoperibólico tipo submarino para la medida de calores de inmersión de sólidos en líquidos. La celda calorimétrica, de una capacidad aproximada de 85 mi, se fabrica en vidrio Pyrex y va sumergida dentro de una chaqueta submarina construida en bronce cromado. El conjunto se introduce dentro de un termostato de agua estabilizado a 25 ±0,001 °C. El sensor de temperatura está constituido por termisiores NTC colocados en un puente de Maier transpuesto y provisto de una Fuente de intensidad constante. La sensibilidad del termómetro es del orden de 5 * I O' °C/p V cuando la corriente de medida en el puente es del orden de 1 mA.

  20. Caloric effects in ferroic materials: new concepts for cooling

    Energy Technology Data Exchange (ETDEWEB)

    Faehler, Sebastian; Roessler, Ulrich K. [IFW Dresden (Germany); Kastner, Oliver; Eggeler, Gunther [Ruhr Universitaet Bochum (Germany); Eckert, Juergen [IFW Dresden (Germany); TU Dresden, Institut fuer Werkstoffwisssenschaft, Dresden (Germany); Emmerich, Heike [Universitaet Bayreuth (Germany); Entel, Peter [Universitaet Duisburg-Essen, Duisburg (Germany); Mueller, Stefan [Institut fuer Angewandte Mathematik, Bonn (Germany); Quandt, Eckhard [Institute for Materials Science, Christian-Albrechts-Universitaet (CAU), Kiel (Germany); Albe, Karsten [TU Darmstadt (Germany)

    2012-02-15

    Refrigeration is one of the main sinks of the German and European electricity consumption and accordingly contributes to worldwide CO{sub 2} emissions. High reduction potentials are envisaged if caloric effects in solid materials are used. The recent discovery of giant entropy changes associated with ferroelastic phase transformations promises higher efficiency. Ferroic transitions enhance the entropy change of magneto-, elasto-, baro-, and electro-caloric effects. Furthermore, because the refrigerant is in a solid state, this technology completely eliminates the need for halofluorocarbon refrigerants having a high global-warming potential. The smaller footprint for operation and the scalable mechanism open up further applications such as cooling of microsystems. While the principal feasibility of magnetocaloric refrigeration is already evident, it requires large magnetic fields (>2 T) which hampers wide industrial and commercial application. It is expected that this obstacle can be overcome by materials with lower hysteresis and by using stress- or electric fields. In order to accelerate research on ferroic cooling, the Deutsche Forschungsgemeinschaft (DFG) decided to establish the priority program SPP 1599 in April 2011. In this article we will address the major challenges for introducing ferroic materials in practical cooling applications: energy efficiency, effect size, and fatigue behavior. Solid state cooling in this sense can be based on the following ''ferroic-caloric'' classes of materials: ferroelastic shape memory alloys, ferromagnetic shape memory alloys, and ferroelectric materials and their possible combinations in materials with ''multicaloric'' effects. The open questions require the interdisciplinary collaboration of material scientists, engineers, physicists, and mathematicians. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. 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.

  2. 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.

  3. Tecnologías emergentes para la conservación de alimentos sin calor

    Directory of Open Access Journals (Sweden)

    Fernández Molina, Juan José

    2001-01-01

    Full Text Available 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 membrana celular que, al ser sometida a campos eléctricos de alta intensidad, se hace permeable formando huecos o poros cuyo tamaño se incrementa a medida que aumenta la intensidad del campo eléctrico o el tiempo de tratamiento o se reduce la resistencia iónica del medio de pulsación. Por otra parte, los PL inducen reacciones fotoquímicas y fototérmicas en los alimentos, causando la muerte de gran cantidad de microorganismos, especialmente en productos alimenticios envasados. Los CMO producen simulación o inhibición en el crecimiento y reproducción de los microorganismos, un simple pulso de intensidad de 5-10 teslas y frecuencias de 5-500 kHz es suficiente para reducir el número de microorganismos en un mínimo de 2 ciclos logarítmicos. Se ha comprobado que estas tecnologías alargan la vida de anaquel de diversos productos alimenticios y pueden ser consideradas como sustitutos parciales de los procesos convencionales de pasteurización y esterilización de alimentos por tratamientos térmicos.

  4. 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

  5. Patterns of intraspecific variability in the response to caloric restriction

    Science.gov (United States)

    Gribble, Kristin E.; Kaido, Oksana; Jarvis, George; Mark Welch, David B.

    2014-01-01

    Caloric restriction (CR) is cited as the most robust means of increasing lifespan across a range of taxa, yet there is a high degree of variability in the response to CR, both within and between species. To examine the intraspecific evolutionary conservation of lifespan extension by CR, we tested the effects of chronic caloric restriction (CCR) at multiple food levels and of intermittent fasting (IF) in twelve isolates from the Brachionus plicatilis species complex of monogonont rotifers. While CCR generally increased or did not change lifespan and total fecundity, IF caused increased, unchanged, or decreased lifespan, depending upon the isolate, and decreased total fecundity in all but one isolate. Lifespan under ad libitum (AL) feeding varied among isolates and predicted the lifespan response to CR: longer-lived isolates under AL were less likely to have a significant increase in lifespan under CCR and were more likely to have a significantly shortened lifespan under IF. Lifespan under AL conditions and the response to CR were not correlated with hydroperiodicity of native habitat or with time in culture. Lack of trade-off between lifespan and fecundity under CCR, and differences in lifespan and fecundity under CCR and IF, even when average food intake was similar, suggest that longevity changes are not always directly determined by energy intake and that CCR and IF regimens extend lifespan through diverse genetic mechanisms. PMID:24384399

  6. Aging, neurogenesis, and caloric restriction in different model organisms.

    Science.gov (United States)

    Arslan-Ergul, Ayca; Ozdemir, A Tugrul; Adams, Michelle M

    2013-08-01

    Brain aging is a multifactorial process that is occurring across multiple cognitive domains. A significant complaint that occurs in the elderly is a decrement in learning and memory ability. Both rodents and zebrafish exhibit a similar problem with memory during aging. The neurobiological changes that underlie this cognitive decline are complex and undoubtedly influenced by many factors. Alterations in the birth of new neurons and neuron turnover may contribute to age-related cognitive problems. Caloric restriction is the only non-genetic intervention that reliably increases life span and healthspan across multiple organisms although the molecular mechanisms are not well-understood. Recently the zebrafish has become a popular model organism for understanding the neurobiological consequences but to date very little work has been performed. Similarly, few studies have examined the effects of dietary restriction in zebrafish. Here we review the literature related to memory decline, neurogenesis, and caloric restriction across model organisms and suggest that zebrafish has the potential to be an important animal model for understanding the complex interactions between age, neurobiological changes in the brain, and dietary regimens or their mimetics as interventions.

  7. Hot or cold? Is monothermal caloric testing useful and cost-effective?

    Science.gov (United States)

    Bush, Matthew L; Bingcang, Christopher M; Chang, Edward T; Fornwalt, Brandon; Rayle, Christopher; Gal, Thomas J; Jones, Raleigh O; Shinn, Jennifer B

    2013-06-01

    Videonystagmography (VNG) is used widely in the assessment of balance dysfunction. The full test battery can be time-consuming and can induce patient discomfort. The purpose of this study was to examine the value of monothermal caloric testing in predicting unilateral caloric weakness, as well as abnormal VNG vestibular and nonvestibular eye movement, while considering the time and reimbursement associated with these tests. In a retrospective review of 645 patients who completed a comprehensive VNG test battery with bithermal caloric testing, we calculated the specificity, sensitivity, and predictive values of monothermal caloric testing in relation to bithermal caloric results and noncaloric VNG results. With unilateral vestibular weakness (UVW) defined as a 25% interear difference, warm-air monothermal caloric testing yielded a sensitivity of 87% and a negative predictive value of 90% for predicting UVW. With a 10% UVW definition, the warm-air caloric testing sensitivity increased to 95% and the negative predictive value to 92%. Warm-air monothermal caloric testing had a positive predictive value of 85% and a negative predictive value of 18% for predicting noncaloric VNG findings; cold-air monothermal and bithermal testing displayed similar results. Isolated monothermal testing is a sensitive screening tool for detecting UVW, but is not adequate for predicting noncaloric VNG results.

  8. 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

    Directory of Open Access Journals (Sweden)

    B. Carciofi

    2002-12-01

    Full Text Available 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 simular uma embalagem. Dois transdutores de fluxo de calor a gradiente tangencial foram previamente instalados no recipiente, revestindo completamente a superfície lateral do mesmo. O recipiente contendo a amostra foi inserido em banho de água circulante à temperatura constante. Os sinais fornecidos pelos transdutores e por termopares inseridos no interior do recipiente foram registrados por um sistema de aquisição de dados computadorizado. Os resultados obtidos com o uso dos transdutores foram comparados com aqueles obtidos através de balanços de energia realizados a partir dos dados experimentais de evolução temporal das temperaturas da amostra junto à superfície interna da embalagem e no centro da mesma. A comparação mostrou que os transdutores de fluxo de calor a gradiente tangencial puderam determinar os fluxos de calor, com tempo de resposta característico dos termopares. Os resultados apresentados mostraram a viabilidade de utilização desses fluxímetros no estudo não destrutivo e não invasivo dos processos de aquecimento e de resfriamento de alimentos, fornecendo informações complementares àquelas obtidas pelo uso de termopares instalados no interior da embalagem.Heat flux determination in thermal processes is classically carried out by appropriate temperature measurements and the application of the Fourier Law. An alternative to this procedure is to determine the heat flux that crosses a surface using heat flux

  9. Índice de reflectancia solar de revestimientos verticales: potencial para la mitigación de la isla de calor urbana

    Directory of Open Access Journals (Sweden)

    Noelia Liliana Alchapar

    Full Text Available La condición artificial del medio urbano modifica el consumo de energía y el confort térmico. El incremento de las temperaturas de una ciudad en relación a las áreas periféricas conduce a la formación de una Isla de Calor Urbana. Es por ello, que trabajar sobre las propiedades termofísicas de los materiales (techos, pavimentos y fachadas es una estrategia de mitigación viable para disminuir las temperaturas de una ciudad. El objetivo principal de éste trabajo es estudiar la capacidad de 80 revestimientos para fachadas disponibles regionalmente para mitigar los efectos negativos de la Isla deCalor Urbana, mediante la determinación del Índice de Reflectancia Solar (SRI. El material que posee el comportamiento más eficiente es el Acrílico Rulato Travertino fino marfil (SRI = 100%, Temp. Sup.= 35 ºC, mientras el más ineficiente es el Acrílico Llaneado fino gris plomo (SRI = 29%, Temp. Sup.= 74 ºC. No obstante existen alternativas intermedias que resultan del efecto combinado de la composición del material, su color y textura. Esta situación demuestra que es posible mitigar el efecto de isla de calor a partir de una adecuada selección de revestimientos verticales.

  10. 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.

  11. Humedad de equilibrio y calor latente de vaporización del ajonjolí. Sésamun indicum L.

    Directory of Open Access Journals (Sweden)

    Julio E. Ospina M.

    1995-01-01

    Full Text Available El ajonjolí (Sésamun indicum L., es una oleaginosa originaria de África y cultivada en las regiones tropicales y subtropicales de Asia y América. A los 110 días de sembrada se cosecha la semilla la cual se utiliza como materia prima especialmente en la industria de grasas y aceites comestibles. Actualmente se pierden en Colombia, un alto porcentaje de semillas durante el proceso de secado natura en el campo. Debido a la falta de información técnica, científica en secado y almacenamiento del grana de ajonjolí se procedió a estudiar la metodología para determinar, el contenido de humedad por el método de la estufa, las curvas y modelo para cuantificar la humedad de equilibrio y el calor latente de vaporización.

  12. 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.

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

    DEFF Research Database (Denmark)

    Stankowska, Arwen Urrsula Malgorzata; Gjedde, Albert

    2013-01-01

    People attempt to change their lifestyle when obesity impairs their quality of life. The attempts often fail when multiple habits must be changed in unison. Here we explore relations among food addiction, the neurobiology of habits, and caloric restriction, when people seek to return to normal......, and reduced activity in prefrontal regions of the cerebral cortex. The neurobiological characteristics suggest that obese people also have a pathological dependence in common with addicts, in the form of food addiction. Malnutrition and dieting both relate to binge eating, possibly as a compensation...... of uncontrolled eating increases dopamine release in the nucleus accumbens. This and other evidence suggests that abuse of food is a habit learned by means of mechanisms centred in the basal ganglia, with an increased risk of relapse in the presence of associative amplifiers. This risk is predicted...

  14. Caloric Restriction in Lean and Obese Strains of Laboratory ...

    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 improved longevity with caloric restriction (CR) in rodents. Little is known regarding effects of CR in genetically lean versus obese strains. Long-Evans (LE) and Brown Norway (BN) rats make an ideal comparison for a CR study because the percentage body fat of young adult LE rats is double that of BN rats. Male LE and BN rats were either fed ad libitum (AL) or were caloricallyrestricted to 80 or 90% of their AL weight. The percentages of fat, lean and fluid mass were measured non-invasively at 2- to 4-week intervals. Metabolic rate and respiratory quotient were measured after 3, 6, 9 and 12 months of CR. Overall health was scored monthly. The percentage of fat of the LE strain decreased with CR, whereas the percentage of fat of the BN strain remained above the AL group for several months. The percentage of lean mass increased above the AL for both strains subjected to CR. The percentage offluid was unaffected by CR. The average metabolic rate over 22 h of the BN rats subjected to CR was reduced, whereas that of LE rats was increased slightly above the AL group. The respiratory quotient of BN rats wasdecreased with CR. Overall health of the CR LE group was significantly improved compared with t

  15. 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.

  16. 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.

  17. Aspects on modeled and the design of a system of refrigeration by absorption attended with solar energy; Aspectos sobre el modelado y diseno de un sistema de refrigeracion por absorcion asistido con energia solar

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Cascales, J. R.; Vera Garcia, F.; Cano Izquierdo, J. M.; Delgado Marin, J. P.; Martinez Sanchez, R.

    2008-07-01

    In this paper, we study the global modelling of an absorption system working with Br Li-H{sub 2}O. It satisfies the air-conditioning necessities of a classroom in an educational centre in Puerto Lumbreras. Murcia. This system utilises a set of solar collector to satisfy the thermal necessities of the vapour generator in the absorption system. For the dynamical simulation of the system we have used the TRNSYS software. The air-conditioned place has been modelled by using a TRNSYS module called PREBID. In this work, special attention is paid to the absorption equipment model developed by using neural networks which has been implemented in TRNSYS. The paper is closed drawing some conclusions. (Author)

  18. Theoretical thermodynamics analysis of cooling cycle bu advanced gas absorption using solar energy; Analisis teorico-experimental de un ciclo de refrigeracion por absorcion avanzado gax, operando con energia solar

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, V. E.; Vidal, A. S.; Garcia, C. A.; Garcia-Valladares, O.; Best, R. B.; Hernandez, J. G.; Velazquez, N. L.

    2004-07-01

    In this article a solar system of refrigeration by absorption with heat exchange generator absorber (GAX) was analyzed. A theoretical thermodynamic analysis of the energetic behavior of the GAX absorption system was made. Experimental results were obtained with generation temperatures of 190 and 220 C, the evaporation temperature was set at 9 C and temperatures of cooling fluids (air and water) were set at 30 C and 28 C, respectively. It was possible to appreciate that the GAX effect decrease whether absorber, type falling film, is operated in option of parallel flow and it was increased when the absorber was operated in option of counterflow. (Author)

  19. Combinación de sistemas de flujo de baja y alta presion para la determinacion de Mg, Ca y Sr en salmueras por espectrofotometria de absorcion atomica con llama

    OpenAIRE

    Neira,José; Poveda,Irma

    2001-01-01

    This article describes the combination of low- and high-pressure flow systems for the determination of Magnesium, Calcium and Strontium by flame atomic absorption spectrometry (FAAS). In the low-pressure system a short C-18 RP column (length 0,5 cm) was utilized for the preconcentration/matrix separation step, xylenol orange was used as chelating agent and tetrabutylamonium acetate for ion pair formation. The hydraulic high pressure nebulization (HHPN) was used for sample transport and sample...

  20. Determination of metallic impurities in raw materials for radioisotope production by atomic absorption spectroscopy; Determinacion de trazas metalicas en amterias primas para la produccion de radioisotopos por espectroscopia de absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M; Alvarez, F; Capdevila, C

    1969-07-01

    Atomic absorption spectrometry has been used for the determination of traces of calcium in scandium oxide, copper in zinc, iron in cobalt oxide, manganese In ferric oxide, nickel in copper and zinc in gallium oxide. The influences on the sensitivities arising from the hollow cathode currents, the gas pressures and the acid concentrations have been considered. A study of the interferences from the metallic matrices has also been performed, the interference due to the absorption of the manganese radiation by the atoms of iron being the most outstanding . In order to remove the interfering elements and increase sensitivity, pre-concentration methods have been tested. The addition methods has also been used. (Author) 14 refs.

  1. Determination of trace amounts of selenium in minerals and rocks by flame less atomic-absorption spectrometry; Determinacion de selinio en minerales y rocas por espectrometria de absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Alduan, F. A.; Capdevilla, C.

    1980-07-01

    The determination of trace amounts of selenium In silicate rocks and feldspar by solvent extraction and graphite furnace atomic-absorption spectrometry has been stu- died. Sodium diethyl-ditio carbamate and ammonium pyrrolidine dithiocarbamate have been tried as chelating agents. The best results are achieved when selenium is extracted Into carbon tetrachloride as the sodium diethyldithiocarbamate complex. The method allows to detect 0,75 ppm of selenium in the sample. Recoveries are about 100%. (Author) 7 refs.

  2. Determination of Cd and Pb in canned pineapple by atomic absorption spectroscopy using a graphite oven; Determinacion de Cd y Pb en pina enlatada por espectrometria de absorcion atomica utilizando horno de grafito

    Energy Technology Data Exchange (ETDEWEB)

    Linares P, G.; Sanchez P, L.; Benavides M, A.; Acosta L, C. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Owing to the food susceptibility to be contaminated it is necessary to realize pursuit studies or frequent monitoring about the content of certain metals which represent health risks by its toxicological effects in the human being and another living organisms. In this work the cadmium and lead concentrations are determined in six national brands of canned pineapple analysing separately sugar sirup and the fruit. (Author)

  3. Influence of soil composition in the determination of chromium by atomic absorption spectrometry with flame air / acetylene; Influencia de la composicion del suelo en la determinacion de cromo por espectrometria de absorcion atomica con llama aire/acetileno

    Energy Technology Data Exchange (ETDEWEB)

    Duran Sosa, Ibis; Granda Valdes, Mayra [Departamento de Quimica Analitica, Facultad de Quimica, Universidad de La Habana, La Habana (Cuba); Pomares Alfonso, Mario Simeon, E-mail: mpomares@imre.oc.uh.cu [Instituto de Ciencias y Tecnologia de Materiales, Universidad de La Habana, La Habana (Cuba)

    2014-07-01

    The Air-acetylene Flame Atomic Absorption determination of chromium is a complex task, being strongly influenced by sample composition and instrumental conditions. The objective of this work was to study the influence of Al, Ca, Fe, K, Mg, and Na on the absorption of chromium in the air-acetylene flame, both separately and combined in solution, when acetylene flow and burner height vary. Dissolutions of the mixtures simulated the composition of four soils from the Quibu River Basin in Havana, Cuba. Chromium absorption first increased and then decreased with increment of acetylene flow for shorter burner heights (∼ 2-4 mm); while a continuous increase was observed for larger heights (> 4 mm). This behavior was the same in the presence and absence of interfering chemical element, mentioned above. On the other hand, the dependence of the magnitude of the interference with acetylene flow and burner height was complex and dependent on the interfering element, particularly at larger heights where the behavior of Al was remarkably different. The interference of the four mixtures of Al, Ca, K, Fe, Mg and Na decreased in comparison to individual interfering effects and was less dependent on acetylene flow and burner height. Finally, a significant reduction of interference on chromium determination in soil samples was achieved by an adequate selection of acetylene flow and burner height.

  4. Energy saving in hotels by means of heat pumps application; Ahorro de energia en hoteles mediante la aplicacion de bombas de calor

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes R, Hernando; Ambriz G, Juan Jose [Universidad Autonoma Metropolitana, Unidad Iztapalapa (Mexico)

    2005-07-15

    The thermal energy is presented as an alternate saving technology for utilities by means of the acute implementation of heat pumps. The objective is to demonstrate the technical and economical feasibility of the application of commercial heat pumps to installations where the handling of opposite temperatures for the conditioning of a space and/or of a fluid is required. In this article it is described the functioning of a heat pump, its different operation principles or types as well as the large diversity of applications they can have in industry, utilities and residential buildings. As an application example the substitution of an electric boiler by a heat pump is presented in a hotel installation and its differences in performance regarding the environmental conditioning of a nearby area and the heating of swimming pool water are analyzed. [Spanish] Se presenta la energia termica como una tecnologia de ahorro alterna para empresas de servicios valiendose de la implementacion agudizada de bombas de calor. El objetivo es demostrar la factibilidad tecnica y economica de la aplicacion de bombas de calor comerciales a instalaciones donde se requiere la manipulacion de temperaturas opuestas para el acondicionamiento de un espacio y/o un fluido. Se describe el funcionamiento de una bomba de calor, sus diferentes principios de operacion o tipos, asi como la gran diversidad de aplicaciones que pueden tener en la industria, empresas de servicios y edificios residenciales. Como ejemplo de aplicacion se presenta la sustitucion de una caldera electrica por una bomba de calor en una instalacion hotelera y sus diferencias de rendimiento en el calentamiento de agua de alberca y el acondicionamiento ambiental de un area cercana.

  5. Evaluación de un recuperador de calor en una industria frigorífica//Evaluation of waste heat recovery in frigorific industry

    Directory of Open Access Journals (Sweden)

    Josué Imbert‐González

    2014-01-01

    Full Text Available La recuperación de calor forma parte de las medidas propuestas para el empleo adecuado del amoniaco en países tropicales. Este artículo analiza un sistema de recuperación de calor instalado en una instalación de refrigeración industrial. En el análisis, que parte de las lecturas comparativas de parámetros de operación de la instalación, se determinó la efectividad del intercambio térmico, el incremento en laeficiencia del sistema de refrigeración, así como el combustible ahorrado por concepto de calentamiento del agua en la industria. Los resultados obtenidos reportaron que el diseño térmico basado en intercambio de calor en espacios anulares, permite un ahorro importante de recursos y un elevado índice de aprovechamiento térmico.Palabras claves: recuperación de calor, instalación frigorífica, ahorro de energía.________________________________________________________________________________AbstractThe waste heat recovery by heat pipes is accepted as an excellent way of saving energy and preventing global warming. This article assesses the impact of the use of a heat exchanger used as a heat recovery in the refrigeration industry. Elements are evaluated from the point of view of heat transfer, evaluating the quality of heat exchange process. Is calculated increase in the efficiency of the cooling system. The heated water is used in the steam generation system of the industry. Is calculated fuel consumption savings resulting from this warming. The findings provide elements that show the enormous potential of this technique in the refrigeration industry.Key words: waste heat recovery, Industrial refrigeration, saving energy.

  6. La vegetación como sistema de control para las Islas de Calor Urbano en Ciudad Juárez, Chihuahua

    Directory of Open Access Journals (Sweden)

    Maria Goretti Salas Esparza

    2017-06-01

    Full Text Available A nivel mundial, el territorio ha experimentado un proceso de urbanización, el cual ha modificado las condiciones físicas y climatológicas como consecuencia de la densificación y construcción de las zonas urbanas, sobre todo a partir de la utilización de materiales que retienen el calor y que propician el fenómeno de isla de calor urbano (ICU, término establecido por Gordon Manley en 1958 (Fernández, 1996. Este trabajo evalúa el impacto que tienen las áreas verdes para actuar como sistema de control de isla de calor sobre Ciudad Juárez, Chihuahua, durante el verano del 2016. La metodología consistió en analizar cuatro áreas verdes para determinar la diferencia de temperatura que existe entre las zonas arboladas y las no arboladas, registrando temperaturas con sensores Hobo®, cada 15 minutos. Los resultados obtenidos demostraron que existe una diferencia de temperatura de 3,82 °C entre los lugares arbolados y no arbolados en el área verde con mayor nivel de vegetación, mientras que el área verde con menor nivel de vegetación se encontró una diferencia de 0,53 °C. Sin embargo, el impacto que tendrán sobre la zona urbana dependerá de la configuración y características de la misma área verde.   Documeto fianciado bajo el marco Tesis de Maestría en Planificación y Desarrollo Urbano " Áreas verdes como sistema de control para las Islas de Calor Urbano en Ciudad Juárez, Chihuahua".Universidad Autónoma de Ciudad Juárez

  7. Eating habits and caloric intake of physically active young boys, ages 10 to 14 years.

    Science.gov (United States)

    Thomson, M J; Cunningham, D A; Wearring, G A

    1980-03-01

    Eating habits of 104 male participants (ages 10 to 14 years) in organized ice hockey were compared across age groups and levels of competition. The boys were members of either a highly skilled and intensively active competitive league group (CL) or a less skilled, moderately active house league group (HL). Eating habits were recorded during a school day from a 24 hour recall questionnaire administered by a trained interviewer. The types and amounts of foods eaten were recorded and caloric intake was calculated. The total caloric intakes were not significantly different by age or competitive group. The boys had higher caloric intakes by age (200 kcal day-1) than reported by other studies but the caloric intake by kilogram of body weight was similar. There was a trend towards larger caloric intake by the CL boys (ages 10 and 11 years), however when divided by body weight the differences were not significant suggesting that this trend was due to a greater body weight of the CL boys and not a significantly increased caloric expenditure. The types of foods eaten (fruit, vegetables, dairy, meat, bread or "empty calories") were similar for the two activity groups and across ages 10 to 14 years. The caloric intakes of dairy and meat products of both groups were significantly higher than for the other food groups.

  8. 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.

  9. Heat and mass transfer during the warming of a bottle of beer = Transferência de calor e massa durante o aquecimento de uma garrafa de cerveja

    Directory of Open Access Journals (Sweden)

    Cláudio Vinicius Barbosa Monteiro

    2010-07-01

    Full Text Available The warming of a bottle of beer during a Friday evening happy hour directly involves transport phenomena, such as mass transfer due to condensation of air humidity on the bottle surface and heat transfer from the ambient to the bottle, which occurs by free convection and water condensation. Both processes happen simultaneously and are directly associated with the heat and mass transfer coefficients involved, which are affected by the ambient humidity and temperature. Several runs were made in several ambient conditions by exposing a cold bottle of beer to varied temperature and humidity and measuring the temperature of beer and the mass of water condensed on the bottle surface over time. From these measures, a theoretical and experimental methodology was developed and applied for the evaluation of the heat and mass transfer coefficients that govern this process. Both the relative humidity and ambient temperature exert a significant influence on the convective heat transfer coefficient. However, the mass transfer coefficient is affected only by the temperature.O aquecimento de uma garrafa de cerveja num “happy-hour” de sexta a tarde envolve diretamente os fenômenos de transferência de massa, devido à condensação da umidade do ar na superfície da garrafa, e de transferência de calor do meio para a garrafa, que ocorre por convecção natural e por condensação de vapor de água. Ambos os processos ocorrem simultaneamente e estão diretamente associados aos coeficientes de transferência de calor e massa envolvidos na dinâmica destes fenômenos e sofrem influência direta da umidade e temperatura ambientes. Neste contexto, efetuaram-se ensaios em diversas condições de temperatura e umidade ambientes, expondo-se uma garrafa de cerveja gelada ao ambiente e medindo-se a temperatura da cerveja e a massa de água condensada ao longo do tempo. A partir destas medidas, desenvolveu-se uma metodologia teórico-experimental que proporcionou a

  10. Relationship of dieting and restrained eating to self-reported caloric intake in female college freshmen.

    Science.gov (United States)

    Goldstein, Stephanie P; Katterman, Shawn N; Lowe, Michael R

    2013-04-01

    Evidence indicates that restrained eaters do not eat less than unrestrained eaters in the natural environment. However, no study has examined caloric intake in those who are currently dieting to lose, or avoid gaining, weight. The current study examined caloric intake using 24-hour food recalls among individuals dieting to lose weight, dieting to avoid weight gain, restrained nondieters, and unrestrained nondieters. Participants were 246 female college students participating in a weight gain prevention trial. The predicted significant difference in caloric intake across the four groups was found for beverage but not for food intake. Results reinforce past literature indicating that dieting/restraint status does not reflect hypo-caloric intake in naturalistic settings. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. 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.

  12. Predicción de la generación interna volumétrica de calor y la capacidad calorífica durante un tratamiento electromagnético del material usando algoritmos híbridos

    Directory of Open Access Journals (Sweden)

    Edgar García-Morantes

    2018-01-01

    Full Text Available Este trabajo considera la estimación de la generación interna volumétrica de calor y la capacidad calorífica de una muestra esférica sólida calentada por un campo electromagnético homogéneo variante en el tiempo. Para tal fin, la estrategia numérica soluciona el correspondiente problema inverso. Tres formas funcionales (lineal, senoidal y exponencial para el campo electromagnético fueron considerados. Ruido blanco fue agregado al perfil de temperatura teórica (i.e. la solución del problema directo para simular una situación más realística. La temperatura se pretendió que fuera leída por cuatro sensores. El problema inverso fue solucionado a través de tres diferentes enfoques: usando un optimizador tradicional, usando técnicas modernas y usando una mezcla de ambos. En el primer caso, usamos un algoritmo determinístico tradicional como lo es el de Levenberg-Marquardt (LM. En el segundo, consideramos tres metaheurísticos estocásticos: El Algoritmo de optimización de la espiral (SOA, la Búsqueda en vórtice (VS, y el método de atracción ponderada (WAM. Para el caso final, proponemos híbridos entre el LM y los algoritmos metahehurísticos. Los resultados muestran que LM converge a la solución esperada solo si las condiciones iniciales (IC están dentro de un rango limitado. Por otra parte, los metaheurísticos convergen en un amplio rango de IC pero muestra baja precisión. Los enfoques híbridos convergen y mejoran la precisión obtenida con los metaheurísticos. La diferencia entre los valores esperados y obtenidos, así como, los errores RMS son reportados y comparados para los tres métodos.

  13. 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.

  14. 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...

  15. Calor específico a bajas temperaturas de alcoholes sólidos vítreos y cristalinos

    Directory of Open Access Journals (Sweden)

    Talón, C.

    2004-02-01

    el vidrio estructural canónico (amorfo. Midiendo y comparando el calor específico a bajas temperaturas de las tres fases, en el rango de temperaturas del pico bosónico (2−10 K así como en el de los estados de tuneleo por debajo de 1K, hemos podido proporcionar una confirmación cuantitativa de que el “comportamiento vítreo” no es una propiedad exclusiva de los sólidos amorfos. Por otra parte, el propanol es el monoalcohol más sencillo que cuenta con dos estereoisómeros (1−y 2−propanol, lo que nos permite estudiar directamente la influencia de la organización espacial de los átomos en las propiedades universales de los vidrios. Hemos medido el calor específico de ambos isómeros, encontrando una notable diferencia cuantitativa entre ellos. Finalmente, también hemos obtenido el calor específico a bajas temperaturas del glicerol en sus fases vítrea y cristalina.

  16. Caloric compensation for sugar-sweetened beverages in meals: A population-based study in Brazil.

    Science.gov (United States)

    Gombi-Vaca, Maria Fernanda; Sichieri, Rosely; Verly, Eliseu

    2016-03-01

    Sugar-sweetened beverage (SSB) consumption can cause positive energy balance, therefore leading to weight gain. A plausible biological mechanism to explain this association is through weak caloric compensation for liquid calories. However, there is an ongoing debate surrounding SSB calorie compensation. The body of evidence comes from a diversity of study designs and highly controlled settings assessing food and beverage intake. Our study aimed to test for caloric compensation of SSB in the free-living setting of daily meals. We analyzed two food records of participants (age 10 years or older) from the 2008-2009 National Dietary Survey (Brazil, N = 34,003). We used multilevel analyses to estimate the within-subject effects of SSB on food intake. Sugar-sweetened beverage calories were not compensated for when comparing daily energy intake over two days for each individual. When comparing meals, we found 42% of caloric compensation for breakfast, no caloric compensation for lunch and zero to 22% of caloric compensation for dinner, differing by household per capita income. In conclusion, SSB consumption contributed to higher energy intake due to weak caloric compensation. Discouraging the intake of SSB especially during lunch and dinner may help reduce excessive energy intake and lead to better weight management. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Caloric stimulation with near infrared radiation does not induce paradoxical nystagmus.

    Science.gov (United States)

    Walther, L E; Asenov, D R; Di Martino, E

    2011-04-01

    Near infrared radiation can be used for warm stimulation in caloric irrigation of the equilibrium organ. Aim of this study was to determine whether near infrared radiation offers effective stimulation of the vestibular organ, whether it is well tolerated by the patients and especially whether it is a viable alternative to warm air stimulation in patients with defects of the tympanic membrane and radical mastoid cavities. Patients with perforations of the tympanic membrane (n = 15) and with radical mastoid cavities (n = 13) were tested both with near infrared radiation and warm dry air. A caloric-induced nystagmus could be seen equally effectively and rapidly in all patients. Contrary to stimulation with warm dry air, no paradoxical nystagmus was observed following caloric irrigation with a warm stimulus (near infrared radiation). Results of a questionnaire showed excellent patient acceptance of near infrared stimulation with no arousal effects or unpleasant feeling. In conclusion, near infrared radiation proved to be an alternative method of caloric irrigation to warm dry air in patients with tympanic membrane defects and radical mastoid cavities. Near infrared radiation is pleasant, quick, contact free, sterile and quiet. With this method an effective caloric warm stimulus is available. If near infrared radiation is used for caloric stimulus no evaporative heat loss occurs.

  18. "Avaliação de três métodos de extração de DNA de dentes humanos submetidos ao calor"

    OpenAIRE

    Vanessa Rosalia Remualdo

    2004-01-01

    Nos casos de carbonização humana usualmente há uma limitação do emprego dos remanescentes biológicos para estudo. Nestes casos, têm-se usado por eleição dentes para análises forenses, já que sua constituição anatômica proporciona proteção ao material genético. No presente estudo avaliou-se a amplificação por PCR do DNA obtido de dentes submetidos ao calor (200°C, 400°C, 500°C e 600°C) durante 60 minutos testando-se três métodos de extração (orgânico, acetato de amônia/isopropanol e sílica). F...

  19. Qualitative analysis by X ray fluorescence of impurities in materials used as air filters; Analisis cualitativo por fluorescencia de rayos X de impurezas en materiales utilizados como filtros de aire

    Energy Technology Data Exchange (ETDEWEB)

    Lartigue G, J; Munoz M, G; Navarrete T, M [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    1995-06-01

    A qualitative analysis of impurities in 5 materials commonly used as air filters was performed with 2 aims: to compare them, in regard to their impurities and to set a methodology to identify spectroscopically, in a short time (1000 seconds), those impurities in order to subtract the blanks signal from that one generated by the collected sample. Some papers on air filters impurities (cellulose, polycarbonate and glass fiber) were found in literature. In one case, the analysis was performed by energy-dispersive X ray fluorescence, tube generated method. In this work it was employed the same method but a radioisotope (Cd-109) was used as primary source. This was applied to 2 of the above mentioned materials as well as to nylon, teflon and quartz. The glass fiber filter had the highest impurity level: Ca, Ba, Pb, Zn, Sr, Rb, and Fe (0.5 {mu}gFe/cm{sup 2}, measured by Atomic Absorption Spectroscopy). The teflon filter had the lowest impurity level. The developed procedure is fast, precise and reproducible and it may be applied also to wastewaters filters. [Spanish] Se realizo el analisis cualitativo de impurezas en cinco materiales comunmente utilizados como filtros de aire, con dos propositos: compararlos en base a sus impurezas y establecer una metodologia que permitiera, en muy corto tiempo (1000 segundos), identificar espectroscopicamente las impurezas a fin de restar la senal del blanco de aquella que genera eventualmente la muestra. En la bibliografia se encontraron algunas publicaciones acerca de impurezas en filtros de aire (celulosa, pollicarbonato y fibra de vidrio), determinadas principalmente por Absorcion Atomica. En un caso, tal determinacion se realizo por Fluorescencia de Rayos X generados en tubo de descargas y detectados por dispersion de energia. En este trabajo se empleo el mismo metodo de Fluorescencia de Rayos X detectados por dispersion de energia pero generados por un radioisotopo (Cd-109) y se aplico a dos de los tres materiales antes

  20. Caloric Sweetener Consumption and Dyslipidemia Among US Adults

    Science.gov (United States)

    Welsh, Jean A.; Sharma, Andrea; Abramson, Jerome L.; Vaccarino, Viola; Gillespie, Cathleen; Vos, Miriam B.

    2011-01-01

    Context Dietary carbohydrates have been associated with dyslipidemia, a lipid profile known to increase cardiovascular disease risk. Added sugars (caloric sweeteners used as ingredients in processed or prepared foods) are an increasing and potentially modifiable component in the US diet. No known studies have examined the association between the consumption of added sugars and lipid measures. Objective To assess the association between consumption of added sugars and blood lipid levels in US adults. Design, Setting, and Participants Cross-sectional study among US adults (n=6113) from the National Health and Nutrition Examination Survey (NHANES) 1999–2006. Respondents were grouped by intake of added sugars using limits specified in dietary recommendations (estimate adjusted mean lipid levels. Logistic regression was used to determine adjusted odds ratios of dyslipidemia. Interactions between added sugars and sex were evaluated. Main Outcome Measures Adjusted mean high-density lipoprotein cholesterol (HDL-C), geometric mean triglycerides, and mean low-density lipoprotein cholesterol (LDL-C) levels and adjusted odds ratios of dyslipidemia, including low HDL-C levels (3.8). Results were weighted to be representative of the US population. Results A mean of 15.8% of consumed calories was from added sugars. Among participants consuming less than 5%, 5% to less than 17.5%, 17.5% to less than 25%, and 25% or greater of total energy as added sugars, adjusted mean HDL-C levels were, respectively, 58.7, 57.5, 53.7, 51.0, and 47.7 mg/dL (Padded sugars) the odds of low HDL-C levels were 50% to more than 300% greater compared with the reference group (added sugars). Conclusion In this study, there was a statistically significant correlation between dietary added sugars and blood lipid levels among US adults. PMID:20407058

  1. 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.

  2. 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

  3. 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

    This proposal entitled "Effects of moderate aerobic exercise combined with caloric restriction on circulating estrogens and IGF-1 in premenopausal women" will provide important contributions regarding...

  4. 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

    2003-01-01

    The proposal entitled "Effects of moderate aerobic exercise combined with caloric restriction on circulating estrogens and IGF-I in premenopausal women will provide important scientific contributions...

  5. Influência da idade e do estresse cíclico de calor no perfil bioquímico sérico em frangos de corte

    Directory of Open Access Journals (Sweden)

    João Paulo Rodrigues Bueno

    2017-06-01

    Full Text Available Objetivou-se avaliar a influência da idade e do estresse cíclico por calor durante uma hora por dia, nas concentrações das proteínas, metabólitos e enzimas séricas em frangos de corte de 21 a 42 dias de idade. Foram utilizados 420 pintos de corte machos, da linhagem Cobb Avian48TM, em um delineamento inteiramente casualizado, composto de dois tratamentos e seis repetições. Os tratamentos foram constituídos de dois ambientes térmicos: um para frangos de corte criados em condições naturais de temperatura e umidade do primeiro ao 42° dia de idade (controle; e outro para estressados por calor à 36 °C do 16° ao 42° dia, durante uma hora do dia (12h00m às 13h00m. No 21º, 28º, 35º e 42º dias de idade, foram coletados em duas aves por repetição aproximadamente 5mL de sangue por punção cardíaca. Foram determinadas em cada amostra de soro as concentrações de proteína total, albumina, globulinas, relação A/G, aspartato aminotransferase, alanina aminotransferase, gama glutamiltransferase, ácido úrico, creatinina, colesterol total, triacilgliceróis, lipoproteínas de alta densidade, lipoproteínas de muito baixa densidade, lipoproteínas de baixa densidade e glicose. Para as concentrações de glicose, ácido úrico, alanina aminotransferase, triacilgliceróis e lipoproteínas de muito baixa densidade, não houve diferenças significativas para ambiente e idade. Observou-se interação significativa entre ambiente e idade para os valores de colesterol e lipoproteínas de baixa densidade. Aos 21 dias de idade o colesterol e as LDL-C foram maiores nas aves em estresse comparados àquelas do tratamento controle, o que não ocorreu nas demais idades. A aspartato aminotransferase nos frangos sob estresse cíclico de calor foi maior em comparação ao tratamento controle e apresentou efeito cúbico para ambiente. A idade das aves influenciou os valores de proteínas totais, albumina, globulina, albumina: globulina, creatinina

  6. Caloric compensation for lunches varying in fat and carbohydrate content by humans in a residential laboratory.

    Science.gov (United States)

    Foltin, R W; Fischman, M W; Moran, T H; Rolls, B J; Kelly, T H

    1990-12-01

    Two groups of three subjects participated in a residential study that assessed the effects of varying the macronutrient and caloric content of a required lunch meal on subsequent food choice and intake. Lunches contained 431 or 844 kcal, with the caloric differential created by manipulating the calories derived from either fat or carbohydrate (CHO). Each lunch condition (high-fat, high-CHO, low-fat, and low-CHO) was examined for 3 consecutive days. Subjects controlled their own patterns of food intake and could consume any item or number of items at any time during the day or night. There were no significant differences in total daily caloric intake across conditions, indicating that subjects compensated for the caloric content of the lunch regardless of the macronutrient content. Total daily caloric intake under the high-fat and high-CHO conditions was 2824 +/- 151 (mean +/- SEM) and 2988 +/- 187 kcal, respectively, whereas intake under the low-fat and low-CHO conditions was 2700 +/- 131 and 2890 +/- 247 kcal, respectively.

  7. Effect of modest caloric restriction on oxidative stress in women, a randomized trial.

    Science.gov (United States)

    Buchowski, Maciej S; Hongu, Nobuko; Acra, Sari; Wang, Li; Warolin, Joshua; Roberts, L Jackson

    2012-01-01

    It is not established to what extent caloric intake must be reduced to lower oxidative stress in humans. The aim of this study was to determine the effect of short-term, moderate caloric restriction on markers of oxidative stress and inflammation in overweight and obese premenopausal women. Randomized trial comparison of 25% caloric restriction (CR) or control diet in 40 overweight or obese women (body mass index 32±5.8 kg/m(2)) observed for 28 days and followed for the next 90 days. Weight, anthropometry, validated markers of oxidative stress (F(2)-isoprostane) and inflammation (C-reactive protein), adipokines, hormones, lipids, interleukins, and blood pressure were assessed at baseline, during the intervention, and at follow-up. Baseline median F(2)-isoprostane concentration (57.0, IQR = 40.5-79.5) in the CR group was 1.75-fold above average range for normal weight women (32.5 pg/ml). After starting of the caloric restriction diet, F(2)-isoprostane levels fell rapidly in the CR group, reaching statistical difference from the control group by day 5 (median 33.5, IQR = 26.0-48.0, Prestriction diet. Three months after resuming a habitual diet, concentrations of F(2)-isoprostane returned to baseline elevated levels in ∼80% of the women. Oxidative stress can be rapidly reduced and sustained through a modest reduction in caloric intake suggesting potential health benefits in overweight and obese women. Clinicaltrials.gov NCT00808275.

  8. Beneficial impact of aerobic exercises on bone mineral density in obese premenopausal women under caloric restriction.

    Science.gov (United States)

    Hosny, Iman Abbas; Elghawabi, Hamed Samir; Younan, Wael Bahat Fahmy; Sabbour, Adly Aly; Gobrial, Mona Abdel Messih

    2012-04-01

    The aim of this study was to assess the impact of caloric restriction diet versus caloric restriction diet combined with aerobic exercises on bone mineral density (BMD) in obese premenopausal women. Forty premenopausal obese women were classified randomly into two groups equal in number. The first group (group A) received caloric restriction diet, while the second (group B) received caloric restriction diet combined with a program of aerobic exercises, over 3 months. The variables measured in this study included age, weight, height, body mass index, fat weight, lean mass, fat percent, basal metabolic rate, and BMD. The comparison between group A and group B showed significantly higher post-treatment lean mass, basal metabolic rate, and BMD in weight-bearing bones (L2-L4 lumbar spine and total hip) in group B compared to group A. In contrast to the BMD of the weight-bearing bones, the BMD of the radius showed significant decrease between the pre- and post-treatment results in groups A and B with no significant differences between the two groups. A greater improvement in the BMD of weight-bearing bones was observed in obese premenopausal women undergoing caloric restriction combined with exercise than in those not undergoing exercise. Anaerobic exercises incorporated into weight loss programs help offset the adverse effects of dietary restriction on bone.

  9. Estimation of beverage consumption and associated caloric intake in adult Czech population. An observational study.

    Science.gov (United States)

    Adámková, Věra; Hubáček, Jaroslav A; Zimmelová, Petra; Velemínský, Miloš

    2011-01-01

    Food intake is a commonly monitored issue in many studies. In contrast, almost no information has been published on beverage intake in adults. To evaluate beverage intake, we studied a population of 1, 200 adults (656 males and 544 females, aged 18-54 years). The volumes and types of beverages were obtained from self-reported questionnaires. The mean beverage intake was highly variable, with a minimum of 450 mL/day and a maximum of 5,330 mL/day. A mean of 1,575 mL/day was found in the entire population (2,300 mL in males and 840 mL in females). Different patterns in the consumption of beverage types were observed between the males and females. For both males and females, the most common beverage consumed was water followed by tea. The next preferable beverages were alcoholic beer, coffee, and non-alcoholic beer in males and coffee, milk, and alcoholic beer in females. The estimated caloric intake from beverages covers, in most individuals, 10-30% of the recommended daily caloric intake. There is substantial variation among individuals, both in beverage intake and in caloric intake through beverages. The caloric intake from beverages reaches, in some individuals, one-third of the recommended daily caloric rate. © 2011 Neuroendocrinology Letters

  10. Heat transfer by natural convection into an horizontal cavity; Transferencia de calor por conveccion natural en una cavidad horizontal

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo J, P

    1998-12-31

    At this thesis it is studied the heat transfer by natural convection in an horizontal cavity, it is involved a boiling`s part that is described the regimes and correlations differences for boiling`s curve. It is designed a horizontal cavity for realize the experimental part and it`s mention from equipment or instrumentation to succeed in a experimentation that permits to realize the analysis of heat transfer, handling as water fluid at atmospheric pressure and where it`s present process from natural convection involving part boiling`s subcooled. The system consists of heater zone submerged in a horizontal cavity with water. Once part finished experimental with information to obtained it`s proceeded to obtain a correlation, realized starting from analysis dimensionless such as: Jakob, Bond and Grasoft (Boiling) besides of knows in natural convection: Prandtl and Nusselt. The mathematical model explains the behavior for natural convection continued part boiling`s subcooled. It is realize analysis graphics too where it`s show comparing with Globe Dropkin and Catton equations by natural convection with bottom heating. (Author)

  11. Heat transfer by natural convection into an horizontal cavity; Transferencia de calor por conveccion natural en una cavidad horizontal

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo J, P

    1999-12-31

    At this thesis it is studied the heat transfer by natural convection in an horizontal cavity, it is involved a boiling`s part that is described the regimes and correlations differences for boiling`s curve. It is designed a horizontal cavity for realize the experimental part and it`s mention from equipment or instrumentation to succeed in a experimentation that permits to realize the analysis of heat transfer, handling as water fluid at atmospheric pressure and where it`s present process from natural convection involving part boiling`s subcooled. The system consists of heater zone submerged in a horizontal cavity with water. Once part finished experimental with information to obtained it`s proceeded to obtain a correlation, realized starting from analysis dimensionless such as: Jakob, Bond and Grasoft (Boiling) besides of knows in natural convection: Prandtl and Nusselt. The mathematical model explains the behavior for natural convection continued part boiling`s subcooled. It is realize analysis graphics too where it`s show comparing with Globe Dropkin and Catton equations by natural convection with bottom heating. (Author)

  12. El calor de la teoría

    Directory of Open Access Journals (Sweden)

    Fernando J. García Selgas

    2015-11-01

    Full Text Available Este trabajo es una reflexión crítica sobre la apuesta metateórica que Alfonso Pérez Agote hace por lo que él denomina “teoría caliente” (TC. Empiezo analizando qué entiende por TC, cómo argumenta su preferencia por ella frente a la “teoría fría” y cómo la aplica de manera efectiva. Tras recordar que esta tesis resulta un salto en el vacío respecto a planteamientos previos mejor asentados, paso a cuestionar algunos de sus supuestos e implicaciones. Todo ello, más el hecho de que la practica sociológica del propio Alfonso parece incumplir su propuesta, viene a mostrar que la tesis de la TC resulta ser una excusa innecesaria y perjudicial para quien, queriendo ceñirse a la investigación empírica, no puede evitar tomar partido en los debates teóricos y ve la realidad social como una realidad predefinida.

  13. The physics of compensating calorimetry and the new CALOR89 code system

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Brau, J.E.; Bishop, B.L.

    1989-03-01

    Much of the understanding of the physics of calorimetry has come from the use of excellent radiation transport codes. A new understanding of compensating calorimetry was introduced four years ago following detailed studies with a new CALOR system. Now, the CALOR system has again been revised to reflect a better comprehension of high energy nuclear collisions by incorporating a modified high energy fragmentation model from FLUKA87. This revision will allow for the accurate analysis of calorimeters at energies of 100's of GeV. Presented in this paper is a discussion of compensating calorimetry, the new CALOR system, the revisions to HETC, and recently generated calorimeter related data on modes of energy deposition and secondary neutron production (E < 50 MeV) in infinite iron and uranium blocks. 38 refs., 5 figs., 5 tabs

  14. 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

    Bile acids released postprandially modify the rate and extent of absorption of lipophilic compounds. The present study aimed to predict gastric emptying (GE) rate and gallbladder emptying (GBE) patterns in response to caloric intake. A mechanism-based model for GE, cholecystokinin plasma concentr......Bile acids released postprandially modify the rate and extent of absorption of lipophilic compounds. The present study aimed to predict gastric emptying (GE) rate and gallbladder emptying (GBE) patterns in response to caloric intake. A mechanism-based model for GE, cholecystokinin plasma...... 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...

  15. 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.

  16. 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.

  17. Hacia un modelo dinámico para la isla de calor urbana de Madrid = Towards a Dynamic Model for the Urban Heat Island of Madrid.

    Directory of Open Access Journals (Sweden)

    Miguel Núñez Peiró

    2016-04-01

    Full Text Available Esta investigación se enmarca dentro del proyecto MODIFICA (modelo predictivo - Edificios - Isla de Calor Urbano, financiado por el Programa de I + D + i Orientada a los Retos de la sociedad 'Retos Investigación' de 2013. Está dirigido a desarrollar un modelo predictivo de eficiencia energética para viviendas, bajo el efecto de isla de calor urbano (AUS con el fin de ponerla en práctica en la evaluación de la demanda de energía real y el consumo en las viviendas. A pesar de los grandes avances que se han logrado durante los últimos años en el rendimiento energético de edificios, los archivos de tiempo utilizados en la construcción de simulaciones de energía se derivan generalmente de estaciones meteorológicas situadas en las afueras de la ciudad. Por lo tanto, el efecto de la Isla de Calor Urbano (ICU no se considera en estos cálculos, lo que implica una importante falta de precisión. Centrado en explorar cómo incluir los fenómenos ICU, el presente trabajo recopila y analiza la dinámica por hora de la temperatura en diferentes lugares dentro de la ciudad de Madrid. Abstract This research is framed within the project MODIFICA (Predictive model - Buildings - Urban Heat Island, funded by Programa de I+D+i orientada a los retos de la sociedad 'Retos Investigación' 2013. It is aimed at developing a predictive model for dwelling energy performance under the Urban Heat Island (UHI effect in order to implement it in the evaluation of real energy demand and consumption in dwellings. Despite great advances on building energy performance have been achieved during the last years, weather files used in building energy simulations are usually derived from weather stations placed in the outskirts of the city. Hence, Urban Heat Island (UHI effect is not considered in this calculations, which implies an important lack of accuracy. Focused on exploring how to include the UHI phenomena, the present paper compiles and analyses the hourly dynamics

  18. Energy saving in heat exchangers of industrial refrigeration systems; Ahorro de energia en intercambiadores de calor en los sistemas de refrigeracion industrial

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, A; Romero Paredes, Hernando; Ambriz, Juan Jose [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D. F. (Mexico)

    1994-12-31

    This paper presents the energy losses of the heat exchangers utilized in industrial refrigeration systems . The effects of the different scaling products on the heat transfer rates are presented and the energy not transferred because of them is evaluated. A simplified method for the evaluation is developed and applied to the evaporators and condensers more frequently employed in the industrial refrigeration systems. The internal and external heat transfer coefficients are evaluated in different types of heat exchangers. The energy losses as a function of the scale thickness on the heat exchanger is shown. [Espanol] El trabajo presenta las perdidas energeticas que se tienen en los intercambiadores de calor usados en los sistemas de refrigeracion industrial. Se presentan los efectos que tienen los diferentes incrustantes en las tasas de transferencia de calor y se evalua la energia que no se transfiere causada por aquellos. Se desarrolla un metodo simplificado de evaluacion y se aplica a los evaporadores y condensadores mas comunes empleados en los sistemas de refrigeracion industrial. Se evaluan los coeficientes internos y externos en diferentes tipos de intercambiadores. Se muestran las perdidas energeticas en funcion del espesor del incrustante en la pared del intercambiador.

  19. Absence of Rotation Perception during Warm Water Caloric Irrigation in Some Seniors with Postural Instability.

    Science.gov (United States)

    Chiarovano, Elodie; Vidal, Pierre-Paul; Magnani, Christophe; Lamas, Georges; Curthoys, Ian S; de Waele, Catherine

    2016-01-01

    Falls in seniors are a major public health problem. Falls lead to fear of falling, reduced mobility, and decreased quality of life. Vestibular dysfunction is one of the fall risk factors. The relationship between objective measures of vestibular responses and age has been studied. However, the effects of age on vestibular perception during caloric stimulation have not been studied. Twenty senior subjects were included in the study, and separated in two groups: 10 seniors reporting postural instability (PI) and exhibiting absence of vestibular perception when they tested with caloric stimulation and 10 sex- and age-matched seniors with no such problems (controls). We assessed vestibular perception on a binary rating scale during the warm irrigation of the caloric test. The function of the various vestibular receptors was assessed using video head impulse test (vHIT), caloric tests, and cervical and ocular vestibular-evoked myogenic potentials. The Equitest was used to evaluate balance. No horizontal canal dysfunction assessed using both caloric test and vHIT was detected in either group. No significant difference was detected between PI and control groups for the peak SPV of caloric-induced ocular nystagmus or for the HVOR gain. All the controls perceived rotation when the maximal SPV during warm irrigation was equal to or ≥15°/s. None of the subjects in the PI group perceived rotation even while the peak SPV exceeded 15°/s, providing objective evidence of normal peripheral horizontal canal function. All the PI group had abnormal Equitest results, particularly in the two last conditions. These investigations show for the first time that vestibular perception can be absent during a caloric test despite normal horizontal canal function. We call this as dissociation vestibular neglect. Patients with poor vestibular perception may not be aware of postural perturbations and so will not correct for them. Thus, falls in the elderly may result, among other factors, from

  20. 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.

  1. Detection of low caloric power of coal by pulse fast-thermal neutron analysis

    International Nuclear Information System (INIS)

    Gu De-shan; Sang Hai-feng; Qiao Shuang; Liu Yu-ren, Liu Lin-mao; Jing Shi-wei; Chinese Academy of Sciences, Changchun

    2004-01-01

    Analysis method and principle of pulse fast-thermal neutron analysis (PFTNA) are introduced. A system for the measurement of low caloric power of coal by PFTNA is also presented. The 14 MeV pulse neutron generator and BGO detector and 4096 MCA were applied in this system. A multiple linear regression method applied to the data solved the interferential problem of multiple elements. The error of low caloric power between chemical analysis and experiment was less than 0.4 MJ/kg. (author)

  2. Second Law Violation By Magneto-Caloric Effect Adiabatic Phase Transition of Type I Superconductive Particles

    Directory of Open Access Journals (Sweden)

    Peter Keefe

    2004-03-01

    Full Text Available Abstract: The nature of the thermodynamic behavior of Type I superconductor particles, having a cross section less than the Ginzburg-Landau temperature dependent coherence length is discussed for magnetic field induced adiabatic phase transitions from the superconductive state to the normal state. Argument is advanced supporting the view that when the adiabatic magneto-caloric process is applied to particles, the phase transition is characterized by a decrease in entropy in violation of traditional formulations of the Second Law, evidenced by attainment of a final process temperature below that which would result from an adiabatic magneto-caloric process applied to bulk dimensioned specimens.

  3. Absence of rotation perception during warm water caloric irrigation in some seniors with postural instability

    Directory of Open Access Journals (Sweden)

    Elodie eChiarovano

    2016-01-01

    Full Text Available Falls in seniors are a major public health problem. Falls lead to fear of falling, reduced mobility and decreased quality of life. Vestibular dysfunction is one of the fall risk factors. The relationship between objective measures of vestibular responses and age has been studied. However, the effects of age on vestibular perception during caloric stimulation have not been studied.Twenty senior subjects were included in the study separated in two groups: 10 seniors reporting postural instability (PI and exhibiting absence of vestibular perception when they tested with caloric stimulation and 10 sex and age-matched seniors with no such problems (controls. We assessed vestibular perception on a binary rating scale during the warm irrigation of the caloric test. The function of the various vestibular receptors was assessed using video-head impulse test (vHIT, caloric tests, and cervical and ocular VEMPs. The Equitest was used to evaluate balance. No horizontal canal dysfunction assessed using both caloric test and vHIT was detected in either group. No significant difference was detected between PI and control groups for the peak SPV of caloric induced ocular nystagmus or for the HVOR gain. All of the controls perceived rotation when the maximal SPV during warm irrigation was equal to or greater than 15°/s. None of the subjects in the PI group perceived rotation even while the peak SPV exceeded 15°/s, providing objective evidence of normal peripheral horizontal canal function. All of the PI group had abnormal Equitest results, particularly in the two last conditions.These investigations show for the first time that vestibular perception can be absent during a caloric test despite normal horizontal canal function. We call this dissociation vestibular neglect. Patients with poor vestibular perception may not be aware of postural perturbations and so will not correct for them. Thus, falls in the elderly may result, amongst other factors, from a

  4. 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.

  5. Determinaciones termogravimétricas y de calor específico de un concentrado comercial de ulexita, entre temperatura ambiente y 1.000 ºC

    Directory of Open Access Journals (Sweden)

    Flores, H. R.

    2006-12-01

    Full Text Available The important amount of hydration water in the ulexite (NaCaB5O9.8H2O, allows using calcination methods to increase its B2O3 content. This paper analyses the thermal decomposition reaction of a preconcentrated ulexite through weight loss measurements, which occur during the heating of samples until 1000 ºC. Determinations of heat content at each temperature were made using an isoperibol calorimeter. The mean specific heat was calculated from these values, and its dependence on temperature was determined. The maximum weight loss was about 32.5 % and the specific heat obtained was 1,13 kJ/kgºC for solid samples and 1,38 kJ/kgºC for fluid samples.The results are useful for the design of the industrial process, in order to determine the thermal requirements for heating calcined ulexite, and to obtain smelted ulexite.

    El elevado contenido de agua de hidratación de la ulexita (NaCaB5O9.8H2O permite utilizar la calcinación como método de concentración. En este trabajo se analiza la reacción de descomposición térmica de un preconcentrado de ulexita a través de determinaciones de la pérdida de peso ocurrida durante el calentamiento de la muestra hasta 1000 ºC. Por otra parte, se ha determinado el valor del calor sensible a cada temperatura ensayada mediante un calorímetro tipo isoperibol y se ha calculado el calor específico medio de la muestra calcinada, así como su variación con la temperatura. Se obtuvieron pérdidas de peso de 32,5 % y valores del calor específico de 1,13 kJ/kgºC para muestras sólidas y 1,38 kJ/kgºC para las fluidas. Los resultados son de utilidad para el diseño del proceso industrial, para la determinación del requerimiento térmico para el calentamiento de ulexita calcinada y para la obtención de una frita.

  6. Excretion of radium in relation to dietary intake; Excretion de radium en fonction de l'ingestion alimentaire; Vydelenie radiya v zavisimosti ot priema ego s pishchej; Excrecion de radio en relacion con su absorcion con los alimentos y el agua

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R. C. [Institute of Cancer Research, Royal Cancer Hospital, London (United Kingdom)

    1963-02-15

    la population de certaines regions du pays. En depit d'activites tres diverses selon les aliments, les taux moyens d'ingestion different fort peu d'un groupe a l'autre, les valeurs se situant entre 2 et 3 pps par personne et par jour. Les teneurs en radium des diverses eaux potables en Grande-Bretagne accusent des differences allant jusqu'a 250 : 1. Toutefois, dans la plupart des cas, les valeurs absolues sont tellem ent faibles par rapport a celles qu'on releve dans les aliments de base que le taux moyen d'ingestion avec l'eau represente 5 a 6% seulement de la dose totale de radium ingeree par chaque personne. Ce n'est que dans une seule region du pays, qui compte moins de 1% de l'ensemble de la population, que l'ingestion journaliere avec l'eau pourrait exceder l'ingestion avec les aliments. En mesurant l'excretion fecale provenant de l'ingestion alimentaire normale, on a constate que pour les jeunes adultes la dose moyenne de {sup 226}Ra ainsi excretee est de 2 a 2,5 ppc par jour. Ce chiffre est en bon accord avec les estimations de l'ingestion journaliere moyenne. Les etudes du metabolisme de l 'organisme humain montrent que la plus grande partie du radium ingere journellement avec les denrees alimentaires est excretee dans les 24 a 48 heures. Cependant, les tentatives faites,pour evaluer la retention fractionnelle chez les adultes ont donne des resultats variables. Les mesures des taux journaliers d'ingestion et d'excretion fecale chez un jeune enfant, poursuivies pendant une duree de 33 jours, montrent que la retention de radium pendant les periodes de croissance osseuse active peut atteindre 10% ou davantage. (author) [Spanish] El autor utilizo los resultados de amplias determinaciones del contenido de {sup 226}Ra en mas de 200 productos alimenticios de uso corriente y en 100 muestras de distintas aguas potables britanicas para comparar la absorcion individual media de radio de dichos origenes, en una serie de grupos profesionales, asi como entre las

  7. 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

  8. Residual tissue post splenectomy detected by splenic scintillography with erythrocytes damaged by heat; Tejido residual postesplenectomia detectado por centellografia esplenica con eritrocitos danados por calor

    Energy Technology Data Exchange (ETDEWEB)

    Rivera B, B; Garcia C, E S; Garcia O, J R [Centro Medico ABC, Departamento de Medicina Nuclear, Mexico, D.F. (Mexico)

    2005-07-01

    Feminine of 26 years old with diagnostic of purple thrombocytopenic idiopathic to those 4 years of age, tried with steroids and splenectomy at 11 years old. Pathway practically asymptomatic until 4 months ago she had presented asthenia, adynamia and general uneasiness, with platelet figures of 40,000 plat/microliter. It was carried out scintillographic study with damaged erythrocytes for post surgical remainder search. Its were took two-dimensional images and tomography by single photon emission (SPECT), being knitted splenic residual in area of anatomical projection of the spleen. (Author)

  9. El comportamiento térmico de la ciudad de Las Palmas de G. C.: La Isla de calor nocturna

    Directory of Open Access Journals (Sweden)

    Lidia Esther Romero Martín

    2013-10-01

    Full Text Available En este trabajo se presentan las principales pautas del comportamiento térmico de la ciudad de Las Palmas de Gran Canaria. Utilizando el método de los recorridos urbanos, durante un año se registraron los datos de temperatura y humedad de 42 puntos de la ciudad, que incluyen áreas formales y funcionales diferentes. Los resultados confirman la existencia de una isla de calor nocturna de carácter bifocal y de intensidad moderada, aunque puede llegar a alcanzar valores de 5.3º C. Su localización está controlada fundamentalmente por la densidad edificatoria y la intensidad del tráfico. El Istmo de la Isleta se comporta como una isla de frescor.In this article, we present the outlines of the thermal behaviour of the city of Las Palmas de Gran Canaria. Using the method of travelling around the city, we recorded temperature and humidity data for 42 sites in the city, including different formal and functional areas. The results confirm that there is a bi-focal and moderate island of nocturnal heat, although it can reach 5.3ºC. This is determined fundamentally by building density and the intensity of the traffic. The Isthmus of La Isleta acts as an island of fresh temperatures.

  10. Vasculitis inducida por metimazol: Reporte de caso

    Directory of Open Access Journals (Sweden)

    Miguel Pinto

    2011-07-01

    Full Text Available Se reporta el caso de una paciente con enfermedad de Graves, que presentó vasculitis asociada al uso de metimazol. Mujer de 14 años, que acudió a consulta por presentar intolerancia al calor, tremor distal y palpitaciones. El examen físico mostró bocio difuso, y el perfil tiroideo, TSH suprimida y hormonas tiroideas elevadas. Los anticuerpos antiperoxidasa tiroidea fueron positivos. Se inició tratamiento con metimazol y beta bloqueadores. Después de 20 días, la paciente regresó por presentar malestar general, fiebre, poliartralgia, lesiones cutáneas maculopapulares y edema de miembros inferiores. Los anticuerpos antinucleares fueron negativos y los anticuerpos anticitoplasma de los neutrófilos (ANCA, positivos. Se suspendió el metimazol y se inició prednisona. Después de 10 días de tratamiento, las molestias desaparecieron y la paciente recibió I 131.Las vasculitis asociadas al uso de tionamidas son poco frecuentes, no dependen de la dosis y están asociadas a la presencia de anticuerpos tipo ANCA. Clásicamente, afectan a los vasos pequeños de la piel; sin embargo, también pueden afectar los riñones y pulmones. El cuadro clínico se caracteriza por artralgias y mialgias. En algunos casos puede ocurrir insuficiencia renal de grado variable. En la mayoría de casos, el cuadro remite con la suspensión de la droga; pero, en algunos se requiere el uso de glucocorticoides o inmunosupresores.(Rev Med Hered 2011;22:147-150.

  11. 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

  12. Previsão tecnológica de médio e longo prazo : bombas de calor e sinergia com energias renováveis

    OpenAIRE

    Antonio Carlos Ventilii Marques

    2013-01-01

    Resumo: O presente trabalho é um estudo de previsão tecnológica para bombas de calor e sua sinergia com energias renováveis. A previsão da evolução das tecnologias é uma atividade relevante para indústria e governos. Existem diversas metodologias à disposição para realizar este tipo de estudo. O domínio dessas metodologias pode trazer ganhos à sociedade ou ser uma condição necessária para a perenidade de empresas. A segurança energética é um tema relevante que induz a procura por alternativas...

  13. Software para la enseñanza de la dinámica y control de intercambiadores de calor de tubos y coraza

    Directory of Open Access Journals (Sweden)

    Fiderman Machuca

    2008-01-01

    Full Text Available Este trabajo presenta la estructura de un software desarrollado para la enseñanza y aprendizaje de la dinámica y control de intercambiadores de calor de tubos y coraza. El programa presenta, de manera numérica y gráfica, el comportamiento dinámico en lazo abierto y cerrado del proceso para diferentes parámetros de diseño y condiciones de operación variables. El software permite modificar condiciones tanto de operación como de diseño, por ejemplo, temperatura y caudales de entrada a los tubos y coraza, número y longitud de tubos, número de pasos, diámetro externo e interno de los tubos, diámetro interno de coraza y factor de ensuciamiento.

  14. Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

    OpenAIRE

    Trepanowski, John F; Canale, Robert E; Marshall, Kate E; Kabir, Mohammad M; Bloomer, Richard J

    2011-01-01

    Abstract Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one...

  15. 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.

  16. Impact of caloric intake in critically ill patients with, and without, refeeding syndrome: A retrospective study.

    Science.gov (United States)

    Olthof, Laura E; Koekkoek, W A C Kristine; van Setten, Coralien; Kars, Johannes C N; van Blokland, Dick; van Zanten, Arthur R H

    2017-08-10

    Refeeding syndrome comprises metabolic disturbances that occur after the reintroduction of feeding after prolonged fasting. Standard care consists of correcting fluid and electrolytes imbalances. Energy intake during refeeding syndrome is heavily debated. This study addresses the effect of caloric intake on outcome during the management of refeeding syndrome. A retrospective study among critically ill invasive mechanically ventilated patients admitted for >7 days to a medical-surgical ICU. Refeeding syndrome was diagnosed by the occurrence of new onset hypophosphatemia (refeeding syndrome were compared and subgroup analysis on energy intake within the refeeding population was performed for the duration of survival. Of 337 enrolled patients, 124 (36.8%) developed refeeding syndrome and 213 patients (63.2%) maintained normal serum phosphate levels. Between the two groups, no statistical significant differences in clinical outcomes were observed. Within the refeeding syndrome group, a reduced 6-month mortality risk for low caloric intake (Refeeding syndrome is common among prolonged mechanically ventilated critically ill patients, however not predictable by baseline characteristics. Among patients that develop refeeding syndrome low caloric intake was associated with a reduction in 6-month mortality risk. This effect was not seen in patients without refeeding syndrome. Findings support caloric restriction in refeeding syndrome during critical illness. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Tema 4. Calor y temperatura (Guía del tema)

    OpenAIRE

    Beléndez Vázquez, Augusto

    2010-01-01

    Guía del "Tema 4. Calor y temperatura" de la asignatura "Fundamentos Físicos de la Ingeniería I" del "Grado en Ingeniería en Sonido e Imagen" impartido en la Escuela Politécnica Superior de la Universidad de Alicante.

  18. Caloric restriction lowers endocannabinoid tonus and improves cardiac function in type 2 diabetes

    NARCIS (Netherlands)

    Eyk, van H.J.; Schinkel, van L.D.; Kantae, V.; Dronkers, C.E.A.; Westenberg, J.J.M.; Roos, de A.; Lamb, H.J.; Jukema, J.W.; Harms, A.C.; Hankemeier, T.; Stelt, van der M.; Jazet, I.M.; Rensen, P.C.N.; Smit, J.W.A.

    2018-01-01

    Background/ObjectivesEndocannabinoids (ECs) are associated with obesity and ectopic fat accumulation, both of which play a role in the development of cardiovascular disease (CVD) in type 2 diabetes (T2D). The effect of prolonged caloric restriction on ECs in relation to fat distribution and cardiac

  19. Effect of solids, caloric content on dual-phase gastric emptying

    Energy Technology Data Exchange (ETDEWEB)

    Van Den Maegdenbergh, V.; Urbain, J.L.; Siegel, J.A.; Mortelmans, L.; De Roo, M. (Univ. Hospital Gasthuisberg, Leuven (Belgium) Temple Univ. Hospital, Philadelphia, PA (USA))

    1990-03-01

    The dual-phase gastric emptying technique is routinely employed to determine the differential emptying of solids and liquids in a wide spectrum of gastrointestinal diseases. Composition, acidity, volume, caloric density, physical form and viscosity of the test means have been shown to be important determinants for the quantitative evaluation of gastric emptying. In this study, the authors have evaluated the effect of increasing the caloric content of the solid portion of a physiologic test mean on both solid and liquid emptying kinetics in health male volunteers. They observed that increasing solid caloric content delayed emptying of both solids and liquids. For the solid phase, the delay was accounted for by a longer lag phase and decrease in emptying rate; for liquids a longer emptying rate was also obtained. They conclude that modification of the caloric content of the solid portion of a meal not only affects the emptying of the solid phase but also alters the emptying of the liquid component of the meal.

  20. Cardiac Frequency and Caloric Cost of Aerobic Dancing in Young Women.

    Science.gov (United States)

    Nelson, Deborah J.; And Others

    1988-01-01

    A study of cardiac frequency during aerobic dancing indicated that it can sustain an elevated cardiac frequency in most cases. The caloric cost of aerobic dancing is approximately 50 percent greater than an equal duration of barre and center-floor exercise by elite ballet dancers. (JD)

  1. 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...

  2. Sensitivity evaluation in air and water caloric stimulation of the vestibular organs using videonystagmography.

    Science.gov (United States)

    Jałocha-Kaczka, Anna; Pietkiewicz, Piotr; Zielińska-Bliźniewska, Hanna; Miłoński, Jarosław; Olszewski, Jurek

    2014-01-01

    The aim of the study was to compare air and water caloric stimulation of the vestibular organs using videonystagmography (VNG). The study covered 18 women aged 21-63 and 11 men aged 21-74 years hospitalized at the ENT, without complaints for vertigo and/or balance disorders. The alternate binaural bithermal caloric test with cool 30°C and warm 44°C air or water irrigations (after 2h interval for the recordings) with the use of VNG was done. All parameters of air and water vestibular caloric stimulations, assessed in the VNG, differed significantly but were within the normal range. The research showed a statistically significant difference between canal paresis but only for the left ear at 30°C and 44°C. Absolute directional preponderance, relative directional preponderance, vestibular excitability, slow component velocity, frequency were different statistically for both ears at both temperatures. Our study showed that both air and water caloric stimulations were able to distinguish physiological and impaired vestibular function. The obtained results showed statistically higher response for water than air stimulation. Copyright © 2014 Polish Otorhinolaryngology - Head and Neck Surgery Society. Published by Elsevier Urban & Partner Sp. z.o.o. All rights reserved.

  3. CONCEPCIONES ALTERNATIVAS SOBRE LOS CONCEPTOS DE ENERGÍA, CALOR Y TEMPERATURA DE LOS DOCENTES EN FORMACION DEL INSTITUTO PEDAGÓGICO EN SANTIAGO, PANAMÁ

    Directory of Open Access Journals (Sweden)

    Viterbo Rodríguez

    2012-01-01

    Full Text Available El artículo presenta los resultados de una investigación realizada en el año 2009 en el Instituto Pedagógico Superior Juan Demóstenes Arosemena. La metodología utilizada en el estudio es del tipo descriptiva cuantitativa y se utilizó una prueba de elección múltiple para recoger los datos. Cada ítem de la prueba centraba la atención en las concepciones alternativas sobre energía, calor y temperatura. Dicha prueba, después de su validación y pilotaje, fue desarrollada por 241 estudiantes de licenciatura de este Instituto. Luego de analizar las respuestas de los ítems, se obtuvo suficiente evidencia para concluir, significativamente, que los docentes en formación tienen concepciones alternativas: el 63.8% sobre el concepto de energía; 69% sobre el concepto de calor, y el 70.7% sobre el concepto de temperatura y movimiento (p=0.05. Las respuestas proporcionadas por los estudiantes demuestran que un elevado número considera que las transformaciones de energía ocurren sin ningún tipo de intercambio ni degradación de la misma. Esto revela su falta de comprensión de las leyes de la termodinámica. Las concepciones alternativas sobre el concepto de energía sugieren tres áreas o líneas principales de problemas: el concepto mismo de energía, los procesos que implican la transferencia de energía y el principio de conservación de la energía.

  4. 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

  5. Health interest modulates brain reward responses to a perceived low-caloric beverage in females.

    Science.gov (United States)

    van Rijn, Inge; Wegman, Joost; Aarts, Esther; de Graaf, Cees; Smeets, Paul A M

    2017-01-01

    Health labels are omnipresent in the supermarket. Such labels give rise to expectations about the product experience and may change flavor perception and perceived reward value. Consumers vary in their degree of health interest and may be differentially affected by such labels. However, how health interest influences neural reward responses to anticipation and receipt of heath-labeled foods is not known. This study assessed to what extent brain responses induced by anticipation and receipt of a beverage with different levels of perceived caloric content are associated with health interest. Twenty-five females completed an fMRI motivational taste-task in which they were presented with a low-caloric cue or a high-caloric cue and subsequently worked for sips of lemonade by moving a joystick. If they responded correctly and in time, they received the lemonade as a reward. Because of the 2 cue types, participants believed they were receiving 2 different lemonades, a high-caloric (HC-receipt) and a low-caloric (LC-receipt) one. Health interest was assessed with the General health interest subscale of the Health and Taste Attitude Scales. Health interest scores correlated significantly (r = .65) with LC-versus HC-receipt activation in the dorsal striatum (putamen), a region involved in encoding food reward. These findings suggest that the reward value of a healthy product compared to its unhealthy counterpart increases with health interest. This provides more insight into the working mechanism of government campaigns that focus on increasing health interest to encourage the formation of healthy eating habits. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  6. 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.

  7. 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 %.

  8. 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,...

  9. 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

  10. Celulitis por citomegalovirus

    Directory of Open Access Journals (Sweden)

    A. Ruiz Lascano

    2002-12-01

    Full Text Available Las lesiones cutáneas por citomegalovirus (CMV son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritematoedematosa. La tratamos con antibióticos sin mejoría, por lo que realizamos un estudio histopatológico de piel que mostró cambios citopáticos compatibles con infección por CMV. Los cultivos bacteriológicos y micológicos fueron negativos. La inmunohistoquímica específica para CMV y el estudio de reacción en cadena de la polimerasa (PCR de la biopsia de piel fueron positivas, al igual que la antigenemia. El tratamiento con ganciclovir produjo la mejoría del cuadro clínico. En la literatura revisada no hemos encontrado la celulitis como manifestación de enfermedad cutánea por CMV.

  11. Caloric density of aquatic macrophytes in different environments of the Baía river subsystem, upper Paraná river floodplain, Brazil

    Directory of Open Access Journals (Sweden)

    Célia de Almeida Lopes

    2006-09-01

    Full Text Available The aim of this work was to determine the caloric density of leaves, stems and roots of aquatic macrophytes in different environments of the Baía subsystem (Baía river and Fechada and Guaraná lagoons on the Upper Paraná river floodplain, in addition to identify the variability between ecological groups. Samplings of Eichhornia crassipes, Salvinia spp, Pistia stratiotes, Eichhornia azurea, Polygonum sp, Cyperaceae and Poaceae were carried out in February 2003. Spatial differences in the caloric densities were not observed for these plants. Caloric density values varied from 1906.9 cal/g dry weight (root to 4675.0 cal/g dry weight (leaf. However, significant differences between the caloric content averages of the vegetative structures were observed only for Polygonum sp and Salvinia spp. In relation to the ecological groups, the highest average value was verified for the emergent macrophytes (3529.7 ± 722.5, which were significantly different from the floating ones (3056.5 ± 571.0. There was no difference between the sites included in the subsystem when the caloric densities were compared.O presente trabalho teve por objetivo determinar a densidade calórica de folhas, caules e raízes de macrófitas aquáticas, em diferentes ambientes do subsistema Baía (Rio Baía e lagoas Fechada e do Guaraná na planície de inundação do alto rio Paraná, além de identificar a variabilidade entre grupos ecológicos. As amostragens foram realizadas em fevereiro de 2003, sendo coletadas amostras de diferentes macrófitas, Eichhornia crassipes, Salvinia spp, Pistia stratiotes, Eichhornia azurea, Polygonum sp, Cyperaceae e Poaceae. Diferenças espaciais nas densidades calóricas não foram observadas para as plantas estudadas. Os valores de densidade calórica variaram de 1906,9 cal/g de peso seco (raiz a 4675,0 cal/g de peso seco (folha. Entretanto, diferenças significativas entre as médias dos conteúdos calóricos das estruturas vegetativas foram

  12. The CaloRIC ASIC: Signal Processing for High Granularity Calorimeter

    International Nuclear Information System (INIS)

    Royer, L; Manen, S; Soumpholphakdy, X; Bonnard, J; Gay, P

    2013-01-01

    A readout ASIC called CaloRIC, has been developed to fulfil the signal processing requirements for the Silicon-Tungsten (Si-W) electromagnetic calorimeter of the International Linear Collider (ILC). This ASIC performs the complete processing of the signal delivered by the Si-PIN diode of the detector: charge sensitive amplification, shaping, analog memorization and digitization. Measurements show a global integral non-linearity better than 0.2% for low energy particles, and limited to 2% for high energy particles. The measured Equivalent Noise Charge (ENC) is evaluated at 0.6 fC, which corresponds to 1/6 times the signal released by a Minimum Ionizing Particle (MIP). With the timing sequence of the ILC, the power consumption of the complete channel is evaluated at 43 μW using a power pulsing. A new ASIC (CaloRIC 4 ch) with four improved readout channels has been designed and is ready for manufacturing.

  13. Effect of the stringency of conditions on caloric test results in healthy subjects.

    Science.gov (United States)

    Krstulovic, Claudio; Tulsidas Mahtani, Bharti; Atrache Al Attrache, Nabil; Pérez-Garrigues, Herminio

    The caloric test is widely used to assess vestibular function, but the conditions in which it is performed can vary. Caloric nystagmus obtained in 57 healthy subjects were compared: 24 subjects studied in ideal conditions and 33 subjects in non-ideal conditions. A statistically significant decrease in the slow phase velocity of the 4 irrigations performed on the subjects in non-ideal conditions was observed. This must be considered, especially in subjects with suspected bilateral involvement. Stringent conditions reduce the risk of misdiagnosis with bilateral deficit. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. All rights reserved.

  14. 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....... visceral fat compared to the active group. Following the two-week period, the inactive group also experienced a poorer glycaemic control, increased endogenous glucose production, decreased hepatic insulin extraction, increased baseline plasma levels of total cholesterol and LDL, and a decreased cognitive...

  15. La Isla de calor en la ciudad de Lloret de Mar

    OpenAIRE

    Moreno García, María del Carmen; Serra Pardo, Juan Antonio

    2017-01-01

    Este artículo muestra el resultado de un trabajo de investigación sobre el fenómeno de la isla de calor en la ciudad de Lloret de Mar, donde se evidencia la existencia del fenómeno y se caracteriza. Utilizando el método de los transectos se han realizado mediciones de temperatura en cuatro campañas anuales entre julio del 2010 y marzo de 2014, durante el verano e invierno. El análisis de los 11.360 valores térmicos recopilados muestra una isla de calor urbana con una intensidad media de 3,3ºC...

  16. Influence of meal weight and caloric content on gastric emptying of meals in man

    International Nuclear Information System (INIS)

    Moore, J.G.; Christian, P.E.; Brown, J.A.; Brophy, C.; Datz, F.; Taylor, A.; Alazraki, N.

    1984-01-01

    This study was designed to assess the relative influence of meal weight and caloric content on gastric emptying of liquid and solid meals in man. A dual radioisotopic method which permits noninvasive and simultaneous measurement of liquid- and solid-phase emptying by external gamma camera techniques was employed. Nine healthy volunteer subjects ingested 50-, 300-, and 900-g lettuce and water meals adjusted to either 68, 208, or 633 kcal with added salad oil. The following observations were made: (1) absolute emptying rates (grams of solid food emptied from the stomach per minute) increased directly and significantly with meal weight; (2) increasing meal total caloric content significantly slowed solid food gastric emptying but did not overcome the enhancing effect of meal weight; and (3) liquid emptying rates were uninfluenced by meal total kcal amount

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

    International Nuclear Information System (INIS)

    Vient, E.

    2016-01-01

    The richness of the data set, collected by the INDRA Collaboration during the last twenty years, enabled 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 ∗ −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.

  18. Influence of meal weight and caloric content on gastric emptying of meals in man

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.G.; Christian, P.E.; Brown, J.A.; Brophy, C.; Datz, F.; Taylor, A.; Alazraki, N.

    1984-06-01

    This study was designed to assess the relative influence of meal weight and caloric content on gastric emptying of liquid and solid meals in man. A dual radioisotopic method which permits noninvasive and simultaneous measurement of liquid- and solid-phase emptying by external gamma camera techniques was employed. Nine healthy volunteer subjects ingested 50-, 300-, and 900-g lettuce and water meals adjusted to either 68, 208, or 633 kcal with added salad oil. The following observations were made: (1) absolute emptying rates (grams of solid food emptied from the stomach per minute) increased directly and significantly with meal weight; (2) increasing meal total caloric content significantly slowed solid food gastric emptying but did not overcome the enhancing effect of meal weight; and (3) liquid emptying rates were uninfluenced by meal total kcal amount.

  19. 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

  20. 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...

  1. 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...

  2. Absence of rotation perception during warm water caloric irrigation in some seniors with postural instability

    OpenAIRE

    Elodie eChiarovano; Pierre-Paul eVidal; Christophe eMagnani; Georges eLamas; Ian S Curthoys; Catherine eDe Waele; Catherine eDe Waele

    2016-01-01

    Falls in seniors are a major public health problem. Falls lead to fear of falling, reduced mobility and decreased quality of life. Vestibular dysfunction is one of the fall risk factors. The relationship between objective measures of vestibular responses and age has been studied. However, the effects of age on vestibular perception during caloric stimulation have not been studied.Twenty senior subjects were included in the study separated in two groups: 10 seniors reporting postural instabili...

  3. Absence of Rotation Perception during Warm Water Caloric Irrigation in Some Seniors with Postural Instability

    OpenAIRE

    Chiarovano, Elodie; Vidal, Pierre-Paul; Magnani, Christophe; Lamas, Georges; Curthoys, Ian S.; de Waele, Catherine

    2016-01-01

    Falls in seniors are a major public health problem. Falls lead to fear of falling, reduced mobility, and decreased quality of life. Vestibular dysfunction is one of the fall risk factors. The relationship between objective measures of vestibular responses and age has been studied. However, the effects of age on vestibular perception during caloric stimulation have not been studied. Twenty senior subjects were included in the study, and separated in two groups: 10 seniors reporting postural in...

  4. Second Law Violation By Magneto-Caloric Effect Adiabatic Phase Transition of Type I Superconductive Particles

    OpenAIRE

    Keefe, Peter

    2004-01-01

    Abstract: The nature of the thermodynamic behavior of Type I superconductor particles, having a cross section less than the Ginzburg-Landau temperature dependent coherence length is discussed for magnetic field induced adiabatic phase transitions from the superconductive state to the normal state. Argument is advanced supporting the view that when the adiabatic magneto-caloric process is applied to particles, the phase transition is characterized by a decrease in entropy in violation of tradi...

  5. 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 food intake (RMANOVA preload-by-weight group interaction p 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.

  6. 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 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.

  7. The influence of caffeine on calorics and cervical vestibular evoked myogenic potentials (cVEMPs).

    Science.gov (United States)

    McNerney, Kathleen; Coad, Mary Lou; Burkard, Robert

    2014-03-01

    Prior to undergoing vestibular function testing, it is not uncommon for clinicians to request that patients abstain from caffeine 24 hr prior to the administration of the tests. However, there is little evidence that caffeine affects vestibular function. To evaluate whether the results from two tests commonly used in a clinical setting to assess vestibular function (i.e., calorics and the cervical vestibular evoked myogenic potential [cVEMP]) are affected by caffeine. Subjects were tested with and without consuming a moderate amount of caffeine prior to undergoing calorics and cVEMPs. Thirty young healthy controls (mean = 23.28 yr; females = 21). Subjects were excluded if they reported any history of vestibular/balance impairment. The Variotherm Plus Caloric Irrigator was used to administer the water, while the I-Portal VNG software was used to collect and analyze subjects' eye movements. The TECA Evoked Potential System was used for the cVEMP stimulus presentation as well as for the data collection. During cVEMP collection, subjects were asked to monitor their sternocleidomastoid muscle contraction with a Delsys EMG monitor. IBM SPSS Statistics 20 was used to statistically analyze the results via paired t-tests. Analysis of the data revealed that ingestion of caffeine did not significantly influence the results of either test of vestibular function. The results revealed that a moderate amount of caffeine does not have a clinically significant effect on the results from caloric and cVEMP tests in young healthy adults. Future research is necessary to determine whether similar results would be obtained from individuals with a vestibular impairment, as well as older adults. American Academy of Audiology.

  8. 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.

  9. Quantifying food intake in socially housed monkeys: social status effects on caloric consumption

    Science.gov (United States)

    Wilson, Mark E.; Fisher, Jeff; Fischer, Andrew; Lee, Vanessa; Harris, Ruth B.; Bartness, Timothy J.

    2008-01-01

    Obesity results from a number of factors including socio-environmental influences and rodent models show that several different stressors increase the preference for calorically dense foods leading to an obese phenotype. We present here a non-human primate model using socially housed adult female macaques living in long-term stable groups given access to diets of different caloric density. Consumption of a low fat (LFD; 15% of calories from fat) and a high fat diet (HFD; 45% of calories from fat) was quantified by means of a custom-built, automated feeder that dispensed a pellet of food when activated by a radiofrequency chip implanted subcutaneously in the animal’s wrist. Socially subordinate females showed indices of chronic psychological stress having reduced glucocorticoid negative feedback and higher frequencies of anxiety-like behavior. Twenty-four hour intakes of both the LFD and HFD were significantly greater in subordinates than dominates, an effect that persisted whether standard monkey chow (13% of calories from fat) was present or absent. Furthermore, although dominants restricted their food intake to daylight, subordinates continued to feed at night. Total caloric intake was significantly correlated with body weight change. Collectively, these results show that food intake can be reliably quantified in non-human primates living in complex social environments and suggest that socially-subordinate females consume more calories, suggesting this ethologically relevant model may help understand how psychosocial stress changes food preferences and consumption leading to obesity. PMID:18486158

  10. Investigation on caloric requirement of biomass pyrolysis using TG-DSC analyzer

    Energy Technology Data Exchange (ETDEWEB)

    He Fang [Institute of Utilization of Biomass, Shandong University of Technology, No. 12, Zhangzhou Road, Zibo, Shandong 255049 (China)]. E-mail: hf@sdut.edu.cn; Yi Weiming [Institute of Utilization of Biomass, Shandong University of Technology, No. 12, Zhangzhou Road, Zibo, Shandong 255049 (China); Bai Xueyuan [Institute of Utilization of Biomass, Shandong University of Technology, No. 12, Zhangzhou Road, Zibo, Shandong 255049 (China)

    2006-09-15

    The caloric requirement of biomass pyrolysis has an important influence on the course of the thermal conversion. However, precise data are difficult to achieve by the current calculation method because of the complexity of the process. A new method for achieving the caloric requirement of the process by integrating the differential scanning calorimetry (DSC) curves was proposed after the simultaneous thermal analyzer (TG-DSC) and DSC curves were investigated. Experiments were conducted for wheat straw, cotton stalk, pine and peanut shell on a Netsch STA 449C analyzer. Powder samples were put into a platinum crucible with a lid on a high accuracy DSC-cp sample holder in the furnace and then heated from ambient temperature up to the maximum temperature of 973 K at the heating rate of 10 K/min in the analyzer. The product gases were swept away by 25 ml/min nitrogen. Mass changes (TG) and calorimetric effects (DSC) were recorded and analyzed. The process was investigated in detail through comparison of the DTG (differential thermogravimetric) and DSC curves of wheat straw. After the water influence in the DSC was eliminated, the relationship of the caloric requirement with the temperature of the aforementioned dry biomass was obtained by integrating the DSC curve. The results showed that 523 kJ, 459 kJ, 646 kJ and 385 kJ were required, respectively, to increase the temperature of 1 kg of dried wheat straw, cotton stalk, pine and peanut from 303 K to 673 K.

  11. 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.

  12. Short-Term Caloric Restriction Suppresses Cardiac Oxidative Stress and Hypertrophy Caused by Chronic Pressure Overload.

    Science.gov (United States)

    Kobara, Miyuki; Furumori-Yukiya, Akiko; Kitamura, Miho; Matsumura, Mihoko; Ohigashi, Makoto; Toba, Hiroe; Nakata, Tetsuo

    2015-08-01

    Caloric restriction (CR) prevents senescent changes, in which reactive oxygen species (ROS) have a critical role. Left ventricular (LV) hypertrophy is a risk factor for cardiovascular diseases. We examined whether CR alters cardiac redox state and hypertrophy from chronic pressure overload. Male c57BL6 mice were subjected to ascending aortic constriction (AAC) with ad libitum caloric intake (AL + AAC group) or 40% restricted caloric intake (CR + AAC group). CR was initiated 2 weeks before AAC and was continued for 4 weeks. Two weeks after constriction, AAC increased LV wall thickness, impaired transmitral flow velocity, and augmented myocyte hypertrophy and fibrosis, in association with enhancement of BNP and collagen III expressions in the AL + AAC group. In the AL + AAC group, oxidative stress in cardiac tissue and mitochondria were enhanced, and NADPH oxidase activity and mitochondrial ROS production were elevated. These changes were significantly attenuated in the CR + AAC group. Additionally, in antioxidant systems, myocardial glutathione peroxidase and superoxide dismutase activities were enhanced in the CR + AAC group. Chronic pressure overload increased cardiac oxidative damage, in association with cardiac hypertrophy and fibrosis. Short-term CR suppressed oxidative stress and improved cardiac function, suggesting that short-term CR could be a useful strategy to prevent pressure overload-induced cardiac injury. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Three-dimensional analysis of post-caloric nystagmus caused by postural change.

    Science.gov (United States)

    Young, Y H; Chiang, C W; Wang, C P

    2001-01-01

    In order to record caloric nystagmus (CN) using three-dimensional videonystagmography (3D VNG) 14 subjects were placed in the supine position with the head tilted up 30 degrees relative to the earth's horizontal plane. After the primary-phase CN had terminated, the subjects were repositioned from a supine to a sitting position, with the head anteflexed 30 degrees for recording the post-caloric nystagmus (PCN). In addition, 8 of the original subjects were placed in the supine position but with the head turned 40 degrees to the left so that the irrigated (right) ear was oriented upwards. After the primary-phase CN had terminated, the subjects were rotated by 180 degrees so that the irrigated ear was oriented downwards to record PCN. The results indicated that both methods successfully provoked horizontal and vertical CN. For torsional CN, the irrigated ear up/down method produced a higher provocation rate (75%) than the supine/sitting method (50%), but the difference was not significant. Comparing the provocation rate of the PCN for the horizontal component revealed that the two methods do not differ significantly. However, when comparing the provocation rates of PCN for the vertical component, the irrigated ear up/down method showed a higher rate (82%) than the supine/sitting method (18%). Thus using 3D VNG coupled with postural change during caloric testing, the horizontal or vertical components of PCN can be successfully provoked.

  14. 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.

  15. Influência da adição de resíduo de gesso no calor de hidratação da argamassa de revestimento interno

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Bernhoeft

    Full Text Available O objetivo do presente trabalho foi analisar a influência da adição de resíduo beneficiado de pasta de gesso como agregado no calor de hidratação da argamassa de gesso para uso em revestimentos internos. Na metodologia utilizada foi fixada a relação água/gesso de 0,66, valor obtido por meio de ensaio de consistência normal, e executados ensaios comparativos entre o gesso natural e o gesso aditivado com 5% e 10 % de resíduo. Para as adições de 5% e 10% de resíduo, os resultados mostraram a diminuição dos tempos de pega (inicial e final diretamente correlacionado ao incremento da adição, claramente observados nas curvas de calor de hidratação, porém sem redução proporcional no tempo útil das argamassas, indicando uma alternativa para a diminuição do tempo improdutivo na mistura da pasta de gesso.

  16. 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.

  17. Activation of the central melanocortin system in rats persistently reduces body and fat mass independently of caloric reduction.

    Science.gov (United States)

    Côté, Isabelle; Green, Sara M; Morgan, Drake; Carter, Christy S; Tümer, Nihal; Scarpace, Philip J

    2018-03-01

    Recent evidence indicate that melanotan II (MTII) reduces body mass independently of caloric reduction. Because MTII induces a transient hypophagia, caloric reduction is still considered a primary mechanism for MTII-mediated body mass loss. To examine the contribution of caloric reduction to long-term body mass loss in response to MTII, we centrally infused MTII or vehicle in ad libitum fed (MTII and Control) animals in comparison with a group of animals that were pair-fed (PF) to the MTII group. Food intake and body mass were recorded daily, and body composition was assessed biweekly. The present study demonstrates that central MTII-mediated body mass loss is only partially mediated by caloric restriction, and the long-term body mass loss is independent of the initial hypophagia. More importantly, central MTII administration induced a rapid but sustained fat mass loss, independently of caloric reduction. MTII-treated animals preserved their lean/fat mass ratio throughout the study, whereas PF animals underwent a transient reduction of lean/fat mass ratio that was only normalized when food intake returned to Control level. In summary, it can be concluded that activation of the central melanocortin system in rats persistently reduces body and fat mass independently of caloric reduction.

  18. Feeding preference of adult females of ribbonfish Trichiurus lepturus through prey proximate-composition and caloric values

    Directory of Open Access Journals (Sweden)

    Vanessa Trindade Bittar

    Full Text Available In the present study we analysed the proximate-composition and caloric values of the preferred prey consumed by ribbonfish, Trichiurus lepturus L. 1758 (adult females, that are distributed in the inner continental shelf from northern Rio de Janeiro State, southeastern Brazil (~22ºS, assessing the potential of nutritional and energetic approach as a tool to understand the feeding selective pattern of this marine top carnivore. The preferred prey of this predator composed of fish co-specifics, Pellona harroweri, Chirocentrodon bleekerianus, Lycengraulis grossidens, Peprilus paru, squid Doryteuthis plei, and shrimp Xiphopenaeus kroyeri were collected from 2007 to 2010 for proximate-composition (water, protein, lipid, ash, and carbohydrate and caloric value analyses. The correspondence analysis showed that protein is the main component in the prey species (61.32% of variance explained, standing out from the other nutrients. Lipid has the highest percentage related to L. grossidens, ash to X. kroyeri and carbohydrate to D. plei. The strong correlations between protein and caloric value (positive and lipid and caloric value (negative indicated that T. lepturus is attending its energy demand through the prey protein content. This work elucidated the feeding preference of adult females of T. lepturus in relation to nutritional and caloric content of their preferred prey. The species showed food selectivity to prey that provide more energy per ingested biomass, so that the feeding events can maximize the predator's caloric gain, which is obtained by a protein-based diet.

  19. Saccharin and aspartame, compared with sucrose, induce greater weight gain in adult Wistar rats, at similar total caloric intake levels.

    Science.gov (United States)

    Feijó, Fernanda de Matos; Ballard, Cíntia Reis; Foletto, Kelly Carraro; Batista, Bruna Aparecida Melo; Neves, Alice Magagnin; Ribeiro, Maria Flávia Marques; Bertoluci, Marcello Casaccia

    2013-01-01

    It has been suggested that the use of nonnutritive sweeteners (NNSs) can lead to weight gain, but evidence regarding their real effect in body weight and satiety is still inconclusive. Using a rat model, the present study compares the effect of saccharin and aspartame to sucrose in body weight gain and in caloric intake. Twenty-nine male Wistar rats received plain yogurt sweetened with 20% sucrose, 0.3% sodium saccharin or 0.4% aspartame, in addition to chow and water ad libitum, while physical activity was restrained. Measurements of cumulative body weight gain, total caloric intake, caloric intake of chow and caloric intake of sweetened yogurt were performed weekly for 12 weeks. Results showed that addition of either saccharin or aspartame to yogurt resulted in increased weight gain compared to addition of sucrose, however total caloric intake was similar among groups. In conclusion, greater weight gain was promoted by the use of saccharin or aspartame, compared with sucrose, and this weight gain was unrelated to caloric intake. We speculate that a decrease in energy expenditure or increase in fluid retention might be involved. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Tendências das séries históricas do índice de calor no município de Santa Maria - RS

    Directory of Open Access Journals (Sweden)

    Stefanía Dalmolin da Silva

    2014-01-01

    Full Text Available Este trabalho teve como objetivo calcular e analisar as séries históricas mensais do Índice de Calor (IC para Santa Maria, RS, Brasil, no período de 1968 a 2011. As variáveis meteorológicas utilizadas neste trabalho foram pressão atmosférica, temperatura do bulbo seco e temperatura do bulbo úmido, no horário das 9h (12UTC, 15h (18UTC e 21h (00UTC. Foi realizada análise de tendência das séries históricas para o valor absoluto e a média mensais do IC através do teste de Mann-Kendall e análise de regressão linear simples para quantificar a tendência, com nível de significância de 95% (α=0,05. Para o valor máximo, no horário das 15h (18UTC, as séries históricas para os meses de janeiro e abril apresentaram acréscimo no valor do índice de calor na magnitude de 0,76°C década-1 e 0,92°C década-1, respectivamente. No horário das 21h (00 UTC, os meses de abril e novembro apresentaram aumento de 0,43°C década-1 e 0,55°C década-1, respectivamente. Porém os meses de maio e agosto apresentaram diminuição de 0,69°C década-1 e 0,31°C década-1, respectivamente.

  1. Análise da distribuição de focos de calor no município de Novo Progresso, Pará

    Directory of Open Access Journals (Sweden)

    Andréia Caroline Lima Lopes

    2017-06-01

    Full Text Available Os incêndios são um dos principais causadores de danos aos ecossistemas florestais. Existem diversas formas de detecção dos focos de calor. Entretanto, para países com grande extensão territorial como o Brasil, é mais eficiente e barato o monitoramento por imagens de satélite. A partir disso, objetivou-se analisar a distribuição de focos de calor no município de Novo Progresso, Pará no período de 2010 a 2015, por meio de dados do monitoramento realizado por satélites de referência pertencentes ao Instituto Nacional de Pesquisas Espaciais. Após a organização das informações obtidas através do Banco de Dados de Queimadas, foram feitas análises dos fatores socioeconômicos e ambientais que intensificam o surgimento de focos de incêndios com o auxílio da literatura científica. Observou-se que os focos se concentraram na região nordeste do munícipio, ao longo da BR-163, apresentando maior ocorrência nos meses de agosto e setembro, o que pode estar relacionado com o período de estiagem do município. Analysis of the Distribution of hotspots in the Novo Progresso Town, Pará, BrazilAbstract: Fires are a major cause of damage to forest ecosystems. There are several ways of detecting hotspots. However, for countries with a vast territory as Brazil, the monitoring by satellite images is more efficient and cheaper. The aim of this study was to analyze the distribution of hotspots in the county of Novo Progresso, Pará, from 2010 to 2015 through data monitoring performed by reference satellites of the National Institute for Space Research. After organizing the information obtained through the Hotspots Database, analyses of socioeconomic and environmental factors that enhance the appearance of fire outbreaks were made with the assistance of scientific literature. It was observed that the outbreaks are concentrated in the northeastern area of the county along the BR-163, presenting higher occurrence in August and September, which

  2. 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

    Full Text Available OBJETIVO: Revisar as possíveis peculiaridades nos mecanismos biológicos referentes às respostas termorregulatórias e sudorípara específicas no exercício realizado por crianças em ambiente de calor. FONTES DE DADOS: Foi feita uma revisão de 47 artigos publicados entre 1960 e 2011 nas bases de dados eletrônicos MedLine e SciELO Brasil, com a utilização dos seguintes descritores: 'crianças', 'calor', 'sudorese', 'termorregulação', 'glândula sudorípara' e 'exercício', sendo usados isoladamente ou em combinação, além de uma tese de doutorado sobre o assunto. SÍNTESE DOS DADOS: Em pré-púberes, a taxa de sudorese durante o esforço é menor em comparação aos adultos. Crianças possuem características termorregulatórias diferenciadas, apresentando um débito de suor por glândula muito menor. A maior razão entre área de superfície e massa corporal faz com que crianças absorvam mais calor durante o exercício sob estresse térmico, elevando o risco de apresentarem sintomas de hipertermia. O maior fluxo sanguíneo para a pele contribui com um melhor controle da homeostase térmica de crianças. O menor tamanho da glândula, a menor sensibilidade colinérgica, os níveis baixos de catecolaminas circulantes durante o esforço e a falta de hormônio androgênico explicam a ocorrência da baixa eliminação de suor no exercício realizado por crianças. CONCLUSÕES: Crianças exibem glândulas sudoríparas imaturas. Assim, a prática de atividade física combinada a altas temperaturas não é bem tolerada havendo maior vulnerabilidade às lesões térmicas. No calor, deve-se ter um controle rigoroso da ingestão de líquidos e um monitoramento atencioso das condições climáticas para maior segurança na prática de exercícios.OBJETIVO: Revisar las posibles peculiaridades en los mecanismos biológicos referentes a las respuestas termorreguladoras y sudorípara específicas en el ejercicio realizado por niños en ambiente de

  3. Electrocardiografo por computadora

    OpenAIRE

    Tinoco Hernandez, Rosanna; Paredes Bejarano, Margarita; Romero Chaglia, Norman; Yapur Auad, Miguel Eduardo

    2009-01-01

    El presente trabajo trata sobrees el diseño y la implementación de un graficador de señales cardiacas por computadora, para lo cual diseñamos un circuito electrónico capaz de recibir la senal analógica proveniente de la actividad electrica del corazón , amplificarla, y luego convertirla en una señal digital para ser procesada por software y finalmente ser graficada, siendo posible así observar la señal cardiaca en el monitor de un computador como un tren de pulsos. Cabe destacar que par...

  4. Indice por Materias

    Directory of Open Access Journals (Sweden)

    Montoya H Luz Marina

    1982-09-01

    Full Text Available Un índice es una lista de palabras o frases indicadores asociados que permite la ubicación de material al interior de un libro o una publicación, en este caso será por el nombre de la materia.

  5. Mild Caloric Restriction Decreases Insulin Requirements in Patients With Type 2 Diabetes and Severe Insulin Resistance.

    Science.gov (United States)

    Meehan, Cristina Adelia; Cochran, Elaine; Mattingly, Megan; Gorden, Phillip; Brown, Rebecca J

    2015-07-01

    Type 2 diabetes (T2D) affects ~10% of the US population, a subset of whom have severe insulin resistance (SIR) (>200 units/d). Treatment of these patients with high-dose insulin presents logistical and compliance challenges. We hypothesized that mild caloric restriction would reduce insulin requirements in patients with T2D and SIR.This was a retrospective study at the National Institutes of Health Clinical Center. Inclusion criteria were as follows: T2D, and insulin dose >200 units/d or >2 units/kg/d. The intervention consisted of mild caloric restriction during a 3 to 6-day hospitalization. The major outcomes were change in insulin dose and blood glucose from admission to discharge.Ten patients met inclusion criteria. Baseline glycated hemoglobin A1c was 10.0 ± 1.6% and body mass index 38.8 ± 9.0 kg/m. Food intake was restricted from 2210 ± 371 kcal/d preadmission to 1810 ± 202 during the hospital stay (16.5% reduction). Insulin dose decreased from 486 ± 291 units/d preadmission to 223 ± 127 at discharge (44% reduction, P = 0.0025). Blood sugars decreased nonsignificantly in the fasting state (from 184 ± 85 to 141 ± 42, P = 0.20), before lunch (239 ± 68 to 180 ± 76, P = 0.057), and at bedtime (212 ± 95 to 176 ± 48, P = 0.19), and significantly decreased before dinner (222 ± 92 to 162 ± 70, P = 0.016).Mild caloric restriction, an accessible and affordable intervention, substantially reduced insulin doses in patients with T2D and SIR. Further studies are needed to determine if the intervention and results are sustainable outside of a hospital setting.

  6. New developments in the study of the caloric curve for finite nuclei within relativistic models

    International Nuclear Information System (INIS)

    Menezes, Debora Peres; Providencia, C.

    2001-01-01

    Relativistic nuclear models have been widely used in describing infinite nuclear matter and finite nuclei properties. With the help of the Thomas Fermi approximation, we have investigated droplet formation in the liquid-gas phase transition in cold and warm asymmetric nuclear matters using the non-linear Walecka model. We have shown that the optimal nuclear size of a droplet in a neutron gas is determined by a delicate balance between nuclear Coulomb and surface energies. On the other hand, the production of several intermediate mass fragments in a short time scale during heavy ion collisions is known as nuclear multifragmentation. In these experiments, the spectator matter has been used to investigate a possible liquid-gas phase transition. The caloric curve, which is given by the excitation energy per nucleon in terms of the thermodynamic temperature is an important quantity to be investigated in the search for a signal of a phase transition. In the present work we obtain the excitation energies of arising droplets in a vapor system, up to T = 6.5 MeV. The droplets are described in terms of a non-linear Walecka-type model with the NL1 parameterization, within the Thomas-Fermi approximation. We conclude that the excitation energies of droplets either corresponding to 150 Sm or 166 Sm, are consistent with the caloric curve in the Fermi gas approximation with a level density parameter A/13. This result agrees with experimental data obtained in heavy-ion collisions at intermediate energies. We have shown that the caloric curve is sensitive to the proton fraction and the inclusion of the Coulomb interaction is important. (author)

  7. 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.

  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. Obesity, Abdominal Obesity, Physical Activity, and Caloric Intake in U.S. Adults: 1988-2010

    Science.gov (United States)

    Ladabaum, Uri; Mannalithara, Ajitha; Myer, Parvathi A.; Singh, Gurkirpal

    2014-01-01

    Background Obesity and abdominal obesity are independently associated with morbidity and mortality. Physical activity attenuates these risks. We examined trends in obesity, abdominal obesity, physical activity, and caloric intake in U.S. adults from 1988 to 2010. Methods Univariate and multivariate analyses were performed using National Health and Nutrition Examination Survey (NHANES) data. Results Average body-mass index (BMI) increased by 0.37% (95% 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 to those with an ideal level of leisure-time physical activity. Conclusions 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. PMID:24631411

  10. Low-Fat Diet With Caloric Restriction Reduces White Matter Microglia Activation During Aging

    Directory of Open Access Journals (Sweden)

    Zhuoran Yin

    2018-03-01

    Full Text Available Rodent models of both aging and obesity are characterized by inflammation in specific brain regions, notably the corpus callosum, fornix, and hypothalamus. Microglia, the resident macrophages of the central nervous system, are important for brain development, neural support, and homeostasis. However, the effects of diet and lifestyle on microglia during aging are only partly understood. Here, we report alterations in microglia phenotype and functions in different brain regions of mice on a high-fat diet (HFD or low-fat diet (LFD during aging and in response to voluntary running wheel exercise. We compared the expression levels of genes involved in immune response, phagocytosis, and metabolism in the hypothalamus of 6-month-old HFD and LFD mice. We also compared the immune response of microglia from HFD or LFD mice to peripheral inflammation induced by intraperitoneal injection of lipopolysaccharide (LPS. Finally, we investigated the effect of diet, physical exercise, and caloric restriction (40% reduction compared to ad libitum intake on microglia in 24-month-old HFD and LFD mice. Changes in diet caused morphological changes in microglia, but did not change the microglia response to LPS-induced systemic inflammation. Expression of phagocytic markers (i.e., Mac-2/Lgals3, Dectin-1/Clec7a, and CD16/CD32 in the white matter microglia of 24-month-old brain was markedly decreased in calorically restricted LFD mice. In conclusion, LFD resulted in reduced activation of microglia, which might be an underlying mechanism for the protective role of caloric restriction during aging-associated decline.

  11. Low-Fat Diet With Caloric Restriction Reduces White Matter Microglia Activation During Aging.

    Science.gov (United States)

    Yin, Zhuoran; Raj, Divya D; Schaafsma, Wandert; van der Heijden, Roel A; Kooistra, Susanne M; Reijne, Aaffien C; Zhang, Xiaoming; Moser, Jill; Brouwer, Nieske; Heeringa, Peter; Yi, Chun-Xia; van Dijk, Gertjan; Laman, Jon D; Boddeke, Erik W G M; Eggen, Bart J L

    2018-01-01

    Rodent models of both aging and obesity are characterized by inflammation in specific brain regions, notably the corpus callosum, fornix, and hypothalamus. Microglia, the resident macrophages of the central nervous system, are important for brain development, neural support, and homeostasis. However, the effects of diet and lifestyle on microglia during aging are only partly understood. Here, we report alterations in microglia phenotype and functions in different brain regions of mice on a high-fat diet (HFD) or low-fat diet (LFD) during aging and in response to voluntary running wheel exercise. We compared the expression levels of genes involved in immune response, phagocytosis, and metabolism in the hypothalamus of 6-month-old HFD and LFD mice. We also compared the immune response of microglia from HFD or LFD mice to peripheral inflammation induced by intraperitoneal injection of lipopolysaccharide (LPS). Finally, we investigated the effect of diet, physical exercise, and caloric restriction (40% reduction compared to ad libitum intake) on microglia in 24-month-old HFD and LFD mice. Changes in diet caused morphological changes in microglia, but did not change the microglia response to LPS-induced systemic inflammation. Expression of phagocytic markers (i.e., Mac-2/Lgals3, Dectin-1/Clec7a, and CD16/CD32) in the white matter microglia of 24-month-old brain was markedly decreased in calorically restricted LFD mice. In conclusion, LFD resulted in reduced activation of microglia, which might be an underlying mechanism for the protective role of caloric restriction during aging-associated decline.

  12. Effect of solid-meal caloric content on gastric emptying kinetics of solids and liquids

    International Nuclear Information System (INIS)

    Urbain, J.L.; Mortelmans, L.; Cutsem, E. van; Maegdenbergh, V. van den; Roo, M. de

    1989-01-01

    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, 111 In-DTPA water and 1 scrambled egg labeled with 99m Tc-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. (orig.) [de

  13. Caloric restriction in C57BL/6J mice mimics therapeutic fasting in humans

    Directory of Open Access Journals (Sweden)

    Denny Christine A

    2006-05-01

    Full Text Available Abstract Background Caloric restriction (CR has long been recognized as a dietary therapy that improves health and increases longevity. Little is known about the persistent effects of CR on plasma biomarkers (glucose, ketone bodies, and lipids following re-feeding in mice. It is also unclear how these biomarker changes in calorically restricted mice relate to those observed previously in calorically restricted humans. Results Three groups of individually housed adult female C57BL/6J (B6 mice (n = 4/group were fed a standard rodent chow diet either: (1 unrestricted (UR; (2 restricted for three weeks to reduce body weight by approximately 15–20% (R; or (3 restricted for three weeks and then re-fed unrestricted (ad libitum for an additional three weeks (R-RF. Body weight and food intake were measured throughout the study, while plasma lipids and levels of glucose and ketone bodies (β-hydroxybutyrate were measured at the termination of the study. Plasma glucose, phosphatidylcholine, cholesterol, and triglycerides were significantly lower in the R mice than in the UR mice. In contrast, plasma fatty acids and β-hydroxybutyrate were significantly higher in the R mice than in the UR mice. CR had no effect on plasma phosphatidylinositol levels. While body weight and plasma lipids of the R-RF mice returned to unrestricted levels upon re-feeding, food intake and glucose levels remained significantly lower than those prior to the initiation of CR. Conclusion CR establishes a new homeostatic state in B6 mice that persists for at least three weeks following ad libitum re-feeding. Moreover, the plasma biomarker changes observed in B6 mice during CR mimic those reported in humans on very low calorie diets or during therapeutic fasting.

  14. 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

  15. 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.

  16. La demanda de las calorías en Venezuela 1970-1995:

    OpenAIRE

    Anido R., José Daniel; Gutiérrez S., Alejandro

    2003-01-01

    1.- Artículos Cartay, Rafael. "Los productos típicos y su reglamentación. Una tentativa de aplicación de la denominación de origen al cacao venezolano" Kalvatchev, Zlatko; Garzaro, Domingo; Guerra Cedezo, Franklin. "Theobroma Cacao L.: Un nuevo enfoque para nutrición y salud" Anido, Daniel; Gutiérrez, Alejandro. "La demanda de las calorías en Venezuela 1970-1995: Algunas evidencias empíricas" Molina, Luisa Elena. "Notas sobre la situación de la producción primaria de arroz en Ven...

  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. Transferência de calor e massa de um condensador evaporativo em escala reduzida

    OpenAIRE

    Ivoni Carlos Acunha Júnior

    2010-01-01

    Este trabalho trata de um estudo experimental da transferência de calor e de massa de um condensador evaporativo, bem como, da relação existente entre as grandezas envolvidas durante a sua operação. Para o desenvolvimento da pesquisa foi construído um condensador evaporativo de pequeno porte com dimensões proporcionais a condensadores comercialmente fabricados no Brasil para operar com R-22 como fluido refrigerante. Este condensador tem 35 colunas e 12 fileiras de tubos de cobre de 6,35 mm de...

  19. On entropy change measurements around first order phase transitions in caloric materials.

    Science.gov (United States)

    Caron, Luana; Ba Doan, Nguyen; Ranno, Laurent

    2017-02-22

    In this work we discuss the measurement protocols for indirect determination of the isothermal entropy change associated with first order phase transitions in caloric materials. The magneto-structural phase transitions giving rise to giant magnetocaloric effects in Cu-doped MnAs and FeRh are used as case studies to exemplify how badly designed protocols may affect isothermal measurements and lead to incorrect entropy change estimations. Isothermal measurement protocols which allow correct assessment of the entropy change around first order phase transitions in both direct and inverse cases are presented.

  20. Dimensionamiento de intercambiadores de calor de coraza y tubos, con ayuda de computador

    Directory of Open Access Journals (Sweden)

    Gabriel Eduardo Rocha Camino

    1985-09-01

    Full Text Available En este trabajo se plantea el problema de optimizar el diseño de un intercambiador de calor del tipo coraza y tubos, y se propone un método para resolverlo, con base en la técnica del "estudio paramétrico de la respuesta". Además, se muestra la necesidad de utilizar el computador como herramienta para Implementar dicho método, y se describe un programa escrito con tal fin.

  1. 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)

    1998-12-31

    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.

  2. Gasto energético e consumo calórico em adolescentes do sexo masculino com diferentes níveis de adiposidade corporal Energy expenditure and caloric intake among male adolescents with different levels of body adiposy

    Directory of Open Access Journals (Sweden)

    Diego Augusto Santos Silva

    2013-03-01

    Full Text Available Foram comparados o gasto energético e consumo calórico de adolescentes com diferentes níveis de gordura corporal. Estudo transversal com 40 adolescentes de 14 a 16 anos do sexo masculino. Os adolescentes foram divididos em dois grupos, cada um com 20 sujeitos, de acordo com o %G: baixo (%G 20%. O gasto energético foi mensurado por acelerômetros triaxiais e recordatório de atividades diárias. O consumo calórico foi avaliado pelo registro de 24 horas. Os jovens com baixo %G tiveram menor consumo calórico ( = 2408,1 ± 557,9 kcal.dia-1 em comparação aos jovens com alto %G ( = 2931,7 ± 679,2 kcal.dia-1, pEnergy expenditure and caloric intake were compared among adolescents with different levels of adiposity. A cross-sectional study was carried with 40 adolescent boys aged 14 to 16 years. The adolescents were divided into two groups of 20 subjects each, according to % body fat (%BF: low ( 20%. Energy expenditure was measured using accelerometer and daily activity diary. The dietary pattern was evaluated based on 24-h recall. Caloric intake was lower in adolescents with low %F ( = 2408.1 ± 557.9 kcal.day-1 compared to those with high %F ( = 2931.7 ± 679.2 kcal.day-1, p<0.05. In addition, they presented greater relative energy expenditure than adolescents with high %F (p<0.05. High %F adolescents showed larger caloric intake than expenditure, while the opposite was observed among low %F males.

  3. Alterações ventilatórias durante o uso de trocadores de calor e umidade em pacientes submetidos à ventilação mecânica com pressão de suporte e ajustes nos parâmetros ventilatórios para compensar estas possíveis alterações: estudo de intervenção autocontrolado em humanos

    Directory of Open Access Journals (Sweden)

    Jeanette Janaina Jaber Lucato

    Full Text Available RESUMO Objetivo: Avaliar as possíveis alterações do volume corrente, volume-minuto e frequência respiratória causadas pela utilização de trocadores de calor e umidade em pacientes submetidos à ventilação mecânica na modalidade pressão de suporte, e quantificar a variação da pressão de suporte necessária para compensar o efeito causado pelo trocador de calor e umidade. Métodos: Os pacientes sob ventilação mecânica invasiva na modalidade pressão de suporte foram avaliados utilizando umidificadores aquecidos e trocadores de calor e umidade. Caso o volume encontrado com uso de trocadores de calor e umidade fosse menor que o achado com o umidificador aquecido, iniciava-se o aumento da pressão de suporte, perante o uso de trocadores de calor e umidade, até ser encontrado um valor de pressão de suporte que possibilitasse ao paciente gerar um valor próximo do volume corrente inicial com umidificador aquecido. A análise foi realizada por meio do teste t pareado, e os valores de incremento foram expressos em porcentagem de aumento necessário. Resultados: Foram avaliados 26 pacientes. O uso de trocadores de calor e umidade aumentou a frequência respiratória, e reduziu o volume corrente e o volume-minuto, quando comparados com o uso do umidificador aquecido. Com o uso de trocadores de calor e umidade, os pacientes precisaram de um incremento de 38,13% na pressão de suporte para manter os volumes prévios. Conclusão: O trocador de calor e umidade alterou os parâmetros de volume corrente, volume-minuto e frequência respiratória, sendo necessário um aumento da pressão de suporte para compensar estas alterações.

  4. Apendicitis por Paracoccidioides brasiliensis

    Directory of Open Access Journals (Sweden)

    Ana Beatriz MUÑOZ URRIBARRI

    2006-01-01

    Full Text Available La paracoccidioidomicosis es la micosis más prevalente en Sudamérica. La forma aguda afecta el sistema fagocítico mononuclear de niños y personas inmunocomprometidas. El compromiso gastrointestinal es frecuente y su patogenia implica diseminación hematógena y linfática. La linfadenomegalia abdominal causa obstrucción intestinal y abdomen agudo. En este artículo damos a conocer el caso de un niño con compromiso gastrointestinal por apendicitis. Este es el primer caso reportado de apendicitis por esta patología. (Rev Med Hered 2006;17:58-60.

  5. Conceptos esenciales de la transmisión de calor en una edificación

    Directory of Open Access Journals (Sweden)

    Safranez, Carlos

    1981-05-01

    Full Text Available Dirigiéndose esta publicación al técnico del ramo de la Construcción, poco familiarizado con los problemas de aislamiento térmico, se presenta una breve exposición de los conceptos esenciales de la transmisión de calor en una edificación. Se exponen ejemplos del cálculo de la resistencia térmica y de la curva de temperatura de una cubierta plana y de un sótano. Se analiza la repercusión del aislamiento térmico sobre el consumo de energía con tiempo frío y tiempo caluroso. Sobre la posibilidad de producirse condensaciones, y sobre la temperatura a que estará expuesta la membrana impermeabilizante de un sótano, debido a la calefacción, con el fin de que no sobrepase los límites fijados. Finalmente, se dan a conocer dos ábacos para la determinación del coeficiente K de la transmisión de calor y de la resistencia térmica R, de distintos tipos de aislamiento.

  6. The publics' understanding of daily caloric recommendations and their perceptions of calorie posting in chain restaurants

    Directory of Open Access Journals (Sweden)

    Bleich Sara N

    2010-03-01

    Full Text Available Abstract Background Calorie posting in chain restaurants has received increasing attention as a policy lever to reduce energy intake. Little research has assessed consumer understanding of overall daily energy requirements or perceived effectiveness of calorie posting. Methods A phone survey was conducted from May 1 through 17, 2009 with 663 randomly selected, nationally-representative adults aged 18 and older, including an oversample of Blacks and Hispanics in the United States. To examine differences in responses by race and ethnicity (White, Black, and Hispanic and gender, we compared responses by conducting chi-squared tests for differences in proportions. Results We found that most Americans were knowledgeable about energy requirements for moderately active men (78% and women (69%, but underestimated energy requirements for inactive adults (60%. Whites had significantly higher caloric literacy and confidence about their caloric knowledge than Blacks and Hispanics (p Conclusion Mandating calorie posting in chain restaurants may be a useful policy tool for promoting energy balance, particularly among Blacks, Hispanics and women who have higher obesity risk.

  7. Diet-beverage consumption and caloric intake among US adults, overall and by body weight.

    Science.gov (United States)

    Bleich, Sara N; Wolfson, Julia A; Vine, Seanna; Wang, Y Claire

    2014-03-01

    We examined national patterns in adult diet-beverage consumption and caloric intake by body-weight status. We analyzed 24-hour dietary recall with National Health and Nutrition Examination Survey 1999-2010 data (adults aged ≥ 20 years; n = 23 965). Overall, 11% of healthy-weight, 19% of overweight, and 22% of obese adults drink diet beverages. Total caloric intake was higher among adults consuming sugar-sweetened beverages (SSBs) compared with diet beverages (2351 kcal/day vs 2203 kcal/day; P = .005). However, the difference was only significant for healthy-weight adults (2302 kcal/day vs 2095 kcal/day; P < .001). Among overweight and obese adults, calories from solid-food consumption were higher among adults consuming diet beverages compared with SSBs (overweight: 1965 kcal/day vs 1874 kcal/day; P = .03; obese: 2058 kcal/day vs 1897 kcal/day; P < .001). The net increase in daily solid-food consumption associated with diet-beverage consumption was 88 kilocalories for overweight and 194 kilocalories for obese adults. Overweight and obese adults drink more diet beverages than healthy-weight adults and consume significantly more solid-food calories and a comparable total calories than overweight and obese adults who drink SSBs. Heavier US adults who drink diet beverages will need to reduce solid-food calorie consumption to lose weight.

  8. High caloric intake at breakfast vs. dinner differentially influences weight loss of overweight and obese women.

    Science.gov (United States)

    Jakubowicz, Daniela; Barnea, Maayan; Wainstein, Julio; Froy, Oren

    2013-12-01

    Few studies examined the association between time-of-day of nutrient intake and the metabolic syndrome. Our goal was to compare a weight loss diet with high caloric intake during breakfast to an isocaloric diet with high caloric intake at dinner. Overweight and obese women (BMI 32.4 ± 1.8 kg/m(2) ) with metabolic syndrome were randomized into two isocaloric (~1400 kcal) weight loss groups, a breakfast (BF) (700 kcal breakfast, 500 kcal lunch, 200 kcal dinner) or a dinner (D) group (200 kcal breakfast, 500 kcal lunch, 700 kcal dinner) for 12 weeks. The BF group showed greater weight loss and waist circumference reduction. Although fasting glucose, insulin, and ghrelin were reduced in both groups, fasting glucose, insulin, and HOMA-IR decreased significantly to a greater extent in the BF group. Mean triglyceride levels decreased by 33.6% in the BF group, but increased by 14.6% in the D group. Oral glucose tolerance test led to a greater decrease of glucose and insulin in the BF group. In response to meal challenges, the overall daily glucose, insulin, ghrelin, and mean hunger scores were significantly lower, whereas mean satiety scores were significantly higher in the BF group. High-calorie breakfast with reduced intake at dinner is beneficial and might be a useful alternative for the management of obesity and metabolic syndrome. Copyright © 2013 The Obesity Society.

  9. Oral nutritional supplementation increases caloric and protein intake in peritoneal dialysis patients.

    Science.gov (United States)

    Boudville, Neil; Rangan, Anna; Moody, Harry

    2003-03-01

    Malnutrition is highly prevalent in peritoneal dialysis (PD) patients and is associated with a poor prognosis. Attempts to improve nutritional status with enteral supplements have yielded poor results. We performed a crossover-design trial on 13 PD patients to investigate whether these patients reduce their food intake after drinking oral nutritional supplements. Patients attended three visits in which they were administered a standard oral nutritional supplement either 2 hours or 30 minutes before lunch or a placebo drink 30 minutes before lunch. Lunch was provided as a self-select buffet-style meal, and food intake was measured. Total intake was calculated by adding the nutritional content of the oral supplement. Patients showed poor food intake, with mean values equaling only 18% of the recommended daily intake for calories and 34% for protein. Drinking the supplement 2 hours before lunch resulted in a significant increase compared with the placebo visit in total caloric (430 to 843 kcal; P lunch. These results indicate that oral nutritional supplements administered before a meal may significantly increase caloric and protein intakes of PD patients. Copyright 2003 by the National Kidney Foundation, Inc.

  10. Caloric vestibular stimulation as a treatment for conversion disorder: A case report and medical hypothesis

    Directory of Open Access Journals (Sweden)

    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.

  11. The ageing phenome: caloric restriction and hormones promote neural cell survival, growth, and de-differentiation.

    Science.gov (United States)

    Timiras, Paola S; Yaghmaie, Farzin; Saeed, Omar; Thung, Elaine; Chinn, Garrett

    2005-01-01

    The phenome represents the observable properties of an organism that have developed under the continued influences of both genome and environmental factors. Phenotypic properties are expressed through the functions of cells, organs and body systems that operate optimally, close to equilibrium. In complex organisms, maintenance of the equilibrium is achieved by the interplay of several regulatory mechanisms. In the elderly, dynamic instability may lead to progressive loss of normal function, failure of adaptation and increased pathology. Extensive research (reported elsewhere in this journal) has demonstrated that genetic manipulations of endocrine signaling in flies, worms and mice increase longevity. Another effective strategy for prolonging the lifespan is caloric restriction: in data presented here, the persistence of estrogen-sensitive cells in the hypothalamus of caloric restricted 22-month-old female mice, may explain the persistence of reproductive function at an age, when reproductive function has long ceased in ad libitum fed controls. Still another strategy utilizes the effects of epidermal growth factor (EGF) to promote in vitro proliferation of neuroglia, astrocytes and oligodendrocytes. Their subsequent de-differentiation generates immature precursor cells potentially capable of differentiating into neuroblasts and neurons. These and other examples suggest that, in terms of functional outcomes, "the genome proposes but the phenome disposes".

  12. Caloric restriction in the presence of attractive food cues: external cues, eating, and weight.

    Science.gov (United States)

    Polivy, Janet; Herman, C Peter; Coelho, Jennifer S

    2008-08-06

    A growing body of research on caloric restriction (CR) in many species of laboratory animals suggests that underfeeding leads to better health and longevity in the calorically-restricted animal (e.g., see [[34]. J.P. Pinel, S. Assanand and D.R. Lehman, (2000). Hunger, eating and ill health. Am Psychol, 55, 1105-1116.], for a review). Although some objections have been raised by scientists concerned about negative psychological and behavioral sequelae of such restriction, advocates of CR continue to urge people to adopt sharply reduced eating regimes in order to increase their longevity. Yet very few people are even attempting to reap the benefits of such restriction. The present paper explores one factor that may deter many humans from drastically reducing their food consumption--the presence of abundant, attractive food cues in the environment. Research on the influence of food cues on food-related behaviors is reviewed to demonstrate that the presence of food cues makes restriction of intake more difficult.

  13. REDES DE INTERCAMBIO DE CALOR APLICADAS A LA ESTERIFICACIÓN DE ACEITES VEGETALES USADOS

    Directory of Open Access Journals (Sweden)

    María F. Laborde

    2014-01-01

    Full Text Available E n este trabajo se presenta la aplicación de redes de intercambio de calor (RIC a la esterificación de aceites vegetales usados (AVUs con catálisis ácida para la producción de biodiesel. Se aplican distintos métodos para obtener las cantidades mínimas de calor y la RIC para una capacidad de procesamiento de 0,19 kg/s de AVUs. Se considera una diferencia de temperatura mínima (∆Tmin de 10°C y los requerimientos mínimos de calentamiento y enfriamiento, resultan ser de 4629,87 W y de 10066,30 W, respectivamente. Al aplicar la red de intercambio calórico disminuye en un 78,92% el servicio de vapor requerido en el proceso y en un 62,48% el servicio de agua de enfriamiento, lo que demuestra que la integración reduce los requerimientos energéticos respecto al proceso no integrado.

  14. 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.

  15. Spatio-temporal pattern of vestibular information processing after brief caloric stimulation

    International Nuclear Information System (INIS)

    Marcelli, Vincenzo; Esposito, Fabrizio; Aragri, Adriana; Furia, Teresa; Riccardi, Pasquale; Tosetti, Michela; Biagi, Laura; Marciano, Elio; Di Salle, Francesco

    2009-01-01

    Processing of vestibular information at the cortical and subcortical level is essential for head and body orientation in space and self-motion perception, but little is known about the neural dynamics of the brain regions of the vestibular system involved in this task. Neuroimaging studies using both galvanic and caloric stimulation have shown that several distinct cortical and subcortical structures can be activated during vestibular information processing. The insular cortex has been often targeted and presented as the central hub of the vestibular cortical system. Since very short pulses of cold water ear irrigation can generate a strong and prolonged vestibular response and a nystagmus, we explored the effects of this type of caloric stimulation for assessing the blood-oxygen-level-dependent (BOLD) dynamics of neural vestibular processing in a whole-brain event-related functional magnetic resonance imaging (fMRI) experiment. We evaluated the spatial layout and the temporal dynamics of the activated cortical and subcortical regions in time-locking with the instant of injection and were able to extract a robust pattern of neural activity involving the contra-lateral insular cortex, the thalamus, the brainstem and the cerebellum. No significant correlation with the temporal envelope of the nystagmus was found. The temporal analysis of the activation profiles highlighted a significantly longer duration of the evoked BOLD activity in the brainstem compared to the insular cortex suggesting a functional de-coupling between cortical and subcortical activity during the vestibular response.

  16. DINÁMICA DE UN REACTOR DE BIOPELÍCULA ANAEROBIA TIPO INTERCAMBIADOR DE CALOR (RBAIC

    Directory of Open Access Journals (Sweden)

    Carlos Ramiro Escalera Vásquez

    2005-01-01

    Full Text Available Las características dinámicas de un reactor de biopelícula anaerobio tipo intercambiador de calor (RBAIC, usado para el tratamiento de aguas residuales de melazas, fueron estudiadas experimentalmente. Se realizaron experimentos para estudiar la respuesta del reactor a las sobrecargas orgánicas. También se estudiaron los efectos de los cambios de temperatura de las paredes calientes y las temperaturas ambientales, sobre la eficiencia del reactor, bajo condiciones de estado estacionario. Se demostró que el RBAIC es estable ante la ocurrencia de sobrecarga orgánica. Se concluyó que existe una separación de fases microbianas dentro del reactor, en condiciones normales de operación. Es decir, las bacterias acidogénicas predominan en la masa líquida recirculante y las heteroacetogénicas y metanogénicas lo hacen en la biopelícula adherida a las paredes calientes de transferencia de calor, lo cual implica que los cambios de la temperatura de la pared afectan de mayor manera a la eficiencia de remoción, que los cambios de temperatura del entorno. El RBAIC es una configuración  novedosa, con características energéticas favorables para el tratamiento de aguas residuales de la industria alimenticia.

  17. Effect of caloric restriction on gut permeability, inflammation markers, and fecal microbiota in obese women.

    Science.gov (United States)

    Ott, Beate; Skurk, Thomas; Hastreiter, Ljiljana; Lagkouvardos, Ilias; Fischer, Sandra; Büttner, Janine; Kellerer, Teresa; Clavel, Thomas; Rychlik, Michael; Haller, Dirk; Hauner, Hans

    2017-09-20

    Recent findings suggest an association between obesity, loss of gut barrier function and changes in microbiota profiles. Our primary objective was to examine the effect of caloric restriction and subsequent weight reduction on gut permeability in obese women. The impact on inflammatory markers and fecal microbiota was also investigated. The 4-week very-low calorie diet (VLCD, 800 kcal/day) induced a mean weight loss of 6.9 ± 1.9 kg accompanied by a reduction in HOMA-IR (Homeostasis model assessment-insulin resistance), fasting plasma glucose and insulin, plasma leptin, and leptin gene expression in subcutaneous adipose tissue. Plasma high-molecular weight adiponectin (HMW adiponectin) was significantly increased after VLCD. Plasma levels of high-sensitivity C-reactive protein (hsCRP) and lipopolysaccharide-binding protein (LBP) were significantly decreased after 28 days of VLCD. Using three different methods, gut paracellular permeability was decreased after VLCD. These changes in clinical parameters were not associated with major consistent changes in dominant bacterial communities in feces. In summary, a 4-week caloric restriction resulted in significant weight loss, improved gut barrier integrity and reduced systemic inflammation in obese women.

  18. EFFECTS TO MODIFY THE CALORIC CONTENT OF WATER ON BODY WEIGHT, WATER, FOOD AND CALORIES CONSUMPTION IN RATS

    Directory of Open Access Journals (Sweden)

    ALMA GABRIELA MARTÍNEZ

    2006-05-01

    Full Text Available Six albino rats were divided in two experimental groups and one control. The experiment began withfifteen days of free access; subsequently experimental groups maintained available three concentrationsof glucose: high, middle and low. First group received high-middle-low-high-middle-low sequence andsecond group received low-middle-high-low-middle-high sequence during six days. Control group notreceived glucose concentrations. Caloric concentration of food never changed. Results suggest thatmodification of caloric concentration in water affects feeding behavior. Nevertheless, water with glucoseconsumption did not change body weight.

  19. Apendicitis por Paracoccidioides brasiliensis.

    OpenAIRE

    MUÑOZ URRIBARRI, Ana Beatriz; CHAPARRO DAMMERT, Eduardo; FERRUFINO LLACH, Juan Carlos; VASQUEZ FLORES, Luciola

    2012-01-01

    La paracoccidioidomicosis es la micosis más prevalente en Sudamérica. La forma aguda afecta el sistema fagocítico mononuclear de niños y personas inmunocomprometidas. El compromiso gastrointestinal es frecuente y su patogenia implica diseminación hematógena y linfática. La linfadenomegalia abdominal causa obstrucción intestinal y abdomen agudo. En este artículo damos a conocer el caso de un niño con compromiso gastrointestinal por apendicitis. Este es el primer caso reportado de apendicitis p...

  20. Meningitis por Streptococcus suis

    OpenAIRE

    Geffner Sclarsky, D. E.; Moreno Muñoz, R.; Campillo Alpera, Mª.S.; Pardo Serrano, F.J.; Gómez Gómez, A.; Martínez-Lozano, Mª.D.

    2001-01-01

    La infección humana por Streptococcus suis (S. suis) es una zoonosis, con un riesgo ocupacional conocido y que suele presentarse como meningitis purulenta, que tiene baja mortalidad y frecuentes secuelas de hipoacusia y ataxia. Se han publicado menos de 150 casos humanos desde el informe original de hace 30 años. Hay una reconocida distribución geográfica viviendo la mayoría de los afectados en el norte de Europa y el sudeste Asiático. En España se han comunicado dos pacientes con enfermedad ...

  1. Por mil devaluados pesos

    Directory of Open Access Journals (Sweden)

    Annie Rodríguez Collázos

    2013-03-01

    Full Text Available El estudio de lo popular y lo urbano hasta ahora se ha centrado en el comportamiento y en algunas relaciones de los habitantes con su entorno. “Por mil devaluados pesos. Publicidad popular y urbana”, pretende explorar las formas de publicidad, dispersas en diferentes espacios populares y urbanos en Bogotá, identificando esquemas y formas características de sus propios códigos comunicativos; se centran en un objeto de estudio consistente en las estrategias publicitarias y los códigos comunicativos en los mensajes publicitarios populares en las subculturas de San Victorino, 7 de Agosto y Sanandresito de San José.

  2. 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…

  3. 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…

  4. 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.

  5. Influência da adição de resíduo de gesso no calor de hidratação da argamassa de revestimento interno

    OpenAIRE

    Bernhoeft,Luiz Fernando; Gusmão,Alexandre Duarte; Tavares,Yêda Vieira Póvoas

    2011-01-01

    O objetivo do presente trabalho foi analisar a influência da adição de resíduo beneficiado de pasta de gesso como agregado no calor de hidratação da argamassa de gesso para uso em revestimentos internos. Na metodologia utilizada foi fixada a relação água/gesso de 0,66, valor obtido por meio de ensaio de consistência normal, e executados ensaios comparativos entre o gesso natural e o gesso aditivado com 5% e 10 % de resíduo. Para as adições de 5% e 10% de resíduo, os resultados mostraram a dim...

  6. Avaliação experimental do coeficiente global de transferência de calor em leito fixo percolado com água - DOI: 10.4025/actascitechnol.v26i1.1551

    Directory of Open Access Journals (Sweden)

    Gylles Ricardo Ströher

    2004-03-01

    Full Text Available Foram efetuados diversos ensaios em um trocador de calor de leito fixo recheado com esferas de aço, percolado por água líquida e aquecido através da parede, medindo-se os perfis de temperatura na parede e no centro do leito em diversas condições experimentais: 3mm ≤ dp ≤ 6,3 mm, 50 L/h 2 = 0,99. Adicionalmente, pôde-se constatar que as temperaturas próximas à parede são muito mais sensíveis a alterações da vazão do que as temperaturas na região central do leito

  7. Sepsis por shigella flexneri

    Directory of Open Access Journals (Sweden)

    César Cabrera C

    2005-04-01

    Full Text Available Se presenta un caso raro de sepsis por Shigella flexneri en una paciente de 45 años de edad quien estando hospitalizada para el estudio de un tumor cerebral, requirió el uso de manitol y dosis altas de corticoides; luego de ello presenta deposiciones líquidas con moco y sangre, desarrolla síndrome de respuesta inflamatoria sistémica, luego se aísla Shigella flexneri en el hemocultivo; recibió tratamiento antibiótico con ciprofloxacina. Se describen las características del caso y se comenta de acuerdo con la revisión de literatura.

  8. Portable exhausters POR-004 SKID B, POR-005 SKID C, POR-006 SKID D storage plan

    International Nuclear Information System (INIS)

    Nelson, O.D.; Keller, G.M.

    1997-01-01

    This document provides a storage plan for portable exhausters POR-004 SKID B, POR-005 SKID C, AND POR-006 SKID D. The exhausters will be stored until they are needed by the TWRS (Tank Waste Remediation Systems) Saltwell Pumping Program. The storage plan provides criteria for portable exhauster storage, periodic inspections during storage, and retrieval from storage

  9. Curcumin and piperine supplementation of obese mice under caloric restriction modulates body fat and interleukin-1beta

    Science.gov (United States)

    Background: Dietary bioactive compounds capable of improving metabolic profiles would be of great value, especially for overweight individuals undergoing a caloric restriction (CR) regimen. Curcumin (Cur), a possible anti-obesity compound, and piperine (Pip), a plausible enhancer of Cur's bioavailab...

  10. Metabolic alterations due to caloric restriction and every other day feeding in normal and growth hormone receptor knockout mice.

    Science.gov (United States)

    Westbrook, Reyhan; Bonkowski, Michael S; Arum, Oge; Strader, April D; Bartke, Andrzej

    2014-01-01

    Mutations causing decreased somatotrophic signaling are known to increase insulin sensitivity and extend life span in mammals. Caloric restriction and every other day (EOD) dietary regimens are associated with similar improvements to insulin signaling and longevity in normal mice; however, these interventions fail to increase insulin sensitivity or life span in growth hormone receptor knockout (GHRKO) mice. To investigate the interactions of the GHRKO mutation with caloric restriction and EOD dietary interventions, we measured changes in the metabolic parameters oxygen consumption (VO2) and respiratory quotient produced by either long-term caloric restriction or EOD in male GHRKO and normal mice. GHRKO mice had increased VO2, which was unaltered by diet. In normal mice, EOD diet caused a significant reduction in VO2 compared with ad libitum (AL) mice during fed and fasted conditions. In normal mice, caloric restriction increased both the range of VO2 and the difference in minimum VO2 between fed and fasted states, whereas EOD diet caused a relatively static VO2 pattern under fed and fasted states. No diet significantly altered the range of VO2 of GHRKO mice under fed conditions. This provides further evidence that longevity-conferring diets cause major metabolic changes in normal mice, but not in GHRKO mice.

  11. 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...

  12. 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.

  13. Comparison of Vestibular Evoked Myogenic Potential and Caloric Tests Findings in Noise Induced Hearing Loss-Affected and Healthy Individuals

    Directory of Open Access Journals (Sweden)

    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.

  14. Behavioural changes are a major contributing factor in the reduction of sarcopenia in caloric-restricted ageing mice

    NARCIS (Netherlands)

    Norren, van K.; Rusli, F.; Dijk, van M.; Lute, C.; Nagel, J.C.; Dijk, F.J.; Dwarkasing, J.T.; Boekschoten, M.V.; Luiking, Y.; Witkamp, R.F.; Müller, M.R.; Steegenga, W.T.

    2015-01-01

    Background - In rodent models, caloric restriction (CR) with maintenance of adequate micronutrient supply has been reported to increase lifespan and to reduce age-induced muscle loss (sarcopenia) during ageing. In the present study, we further investigated effects of CR on the onset and severity of

  15. Acute and short-term effects of caloric restriction on metabolic profile and brain activation in obese, postmenopausal women

    NARCIS (Netherlands)

    Jakobsdottir, S.; van Nieuwpoort, I. C.; van Bunderen, C. C.; de Ruiter, M. B.; Twisk, J. W. R.; Deijen, J. B.; Veltman, D. J.; Drent, M. L.

    2016-01-01

    Early anthropometric and metabolic changes during a caloric-restricted diet in obese postmenopausal women and correlations between these factors with activity in brain areas involved in processing of visual food related stimuli were investigated. An 8-week prospective intervention study of 18

  16. Acute and short term effects of caloric restriction on metabolic profile and brain activation in obese, postmenopausal women.

    NARCIS (Netherlands)

    Jakobsdottir, S.; van Nieuwpoort, I.C.; van Bunderen, C.C.; de Ruiter, M.B.; Twisk, J.W.R.; Deijen, J.B.; Veltman, D.J.; Drent, M.L.

    2016-01-01

    OBJECTIVE:Early anthropometric and metabolic changes during a caloric-restricted diet in obese postmenopausal women and correlations between these factors with activity in brain areas involved in processing of visual food related stimuli were investigated.SUBJECTS AND METHODS:An 8-week prospective

  17. 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.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

  18. Influence of gender, parity, and caloric load on gastrorectal response in healthy subjects: a barostat study.

    Science.gov (United States)

    Sloots, Cornelius E J; Felt-Bersma, Richelle J F; Meuwissen, Stephan G M; Kuipers, Ernst J

    2003-03-01

    The gastrocolonic response consists of a prompt increase in colonic tone after a meal. With a barostat and a high compliant air-filled bag, it is possible to measure rectal tone by recording changes in volume at a constant intrabag pressure. The aim of this study was to evaluate the gastrorectal response in males and females as well as the effect of different caloric loads on the gastrorectal response. In 33 volunteers a barostat procedure during basal conditions and after a 600-kcal meal was performed. In 26 volunteers the procedure was repeated with a 1000-kcal meal. A meal response was defined as a decrease in volume of more than 10%. Phasic volume events (PVE) were defined as a 10% decrease in volume of 15-60 sec duration. After a 600-kcal meal, the decrease in volume after 1 hr was 28 +/- 7% (mean +/- SEM, P parity should be made when results are compared.

  19. Left caloric vestibular stimulation as a tool to reveal implicit and explicit parameters of body representation.

    Science.gov (United States)

    Sedda, A; Tonin, D; Salvato, G; Gandola, M; Bottini, G

    2016-04-01

    Homeostatic parameters, such as temperature, are related to body representation. In this study, we measured whether caloric vestibular stimulation (CVS) alters body temperature and tactile processing, and if in the direction predicted by a holistic body matrix representation. Skin temperature and tactile two-point discrimination (TPD) acuity were measured for both arms before, immediately after and with a delay from CVS. Participants were also administered a personality questionnaire and an anxiety inventory to rule out confounding factors. Two control experiments were planned to exclude casual variations. Our results show that temperature drops significantly in both arms after CVS. CVS also induces a bilateral improvement in tactile acuity (even though not immediately after but in the delayed condition). Finally, these effects are not due to learning, as demonstrated by the control experiment. In summary, our results suggest that vestibular stimulation updates body representation, supporting the evidence in favor of a body matrix. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Physical-chemical, caloric and sensory characterization of light jambolan (Syzygium cumini Lamarck jelly

    Directory of Open Access Journals (Sweden)

    Ellen Silva Lago-Vanzela

    2011-09-01

    Full Text Available In Brazil, several little economically explored fruits have good potential as raw material for the agro-industry. This study aimed to produce and determine the physical-chemical and sensory characteristics of light jambolan jelly. This fruit has intense purple color, which gave the jellies - both standard and light - a quite attractive visual aspect. The light jellies exhibited similar physical-chemical characteristics to the ones developed through the conventional method and; with the proportion of sweeteners used, the caloric values of the formulations were reduced to the range of 41 to 53%, attending the requirements of the Brazilian legislation for this type of product. The sensory profile obtained for the 4 light formulations developed, clearly showed the tasters' preference for the jelly elaborated with the association of cyclamate and saccharin. Thus, the results revealed good perspectives for the application of this fruit in the food industry.

  1. 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.

  2. Physiological-metabolic variables of caloric stress in cows under silvopastoral and prairie without trees

    International Nuclear Information System (INIS)

    Barragan Hernandez, Wilson Andres; Cajas-Giron, Yasmin Socorro; Mahecha-Ledesma, Lilliana

    2015-01-01

    Changes in physiological and metabolic parameters were assessed as indicators of caloric stress of cows under grazing were investigated. The study was developed at the Centro de Investigacion Corpoica Turipana, Region Caribe, Cerete, Colombia, during the years 2011-2012. Temperature (T) and relative humidity (H), and in animals: rectal temperature (RT), skin temperature (TP), respiratory rate (RF) and acid-base status were determined. The variables were measured in the morning (6:00 h) and in the afternoon (13:00 h). Effect of treatment on environmental temperature was found with 7 and 6% less temperature in p-Arbur-Arbor and p-Arbor, respectively, compared with the grass treatment. There was an effect of time (p [es

  3. Modulation infrared thermometry of caloric effects at up to kHz frequencies

    Science.gov (United States)

    Döntgen, Jago; Rudolph, Jörg; Waske, Anja; Hägele, Daniel

    2018-03-01

    We present a novel non-contact method for the direct measurement of caloric effects in low volume samples. The adiabatic temperature change ΔT of a magnetocaloric sample is very sensitively determined from thermal radiation. Rapid modulation of ΔT is induced by an oscillating external magnetic field. Detection of thermal radiation with a mercury-cadmium-telluride detector allows for measurements at field frequencies exceeding 1 kHz. In contrast to thermoacoustic methods, our method can be employed in vacuum which enhances adiabatic conditions especially in the case of small volume samples. Systematic measurements of the magnetocaloric effect as a function of temperature, magnetic field amplitude, and modulation frequency give a detailed picture of the thermal behavior of the sample. Highly sensitive measurements of the magnetocaloric effect are demonstrated on a 2 mm thick sample of gadolinium and a 60 μm thick Fe80B12Nb8 ribbon.

  4. Higher Caloric Refeeding Is Safe in Hospitalised Adolescent Patients with Restrictive Eating Disorders

    Directory of Open Access Journals (Sweden)

    Elizabeth K. Parker

    2016-01-01

    Full Text Available Introduction. This study examines weight gain and assesses complications associated with refeeding hospitalised adolescents with restrictive eating disorders (EDs prescribed initial calories above current recommendations. Methods. Patients admitted to an adolescent ED structured “rapid refeeding” program for >48 hours and receiving ≥2400 kcal/day were included in a 3-year retrospective chart review. Results. The mean (SD age of the 162 adolescents was 16.7 years (0.9, admission % median BMI was 80.1% (10.2, and discharge % median BMI was 93.1% (7.0. The mean (SD starting caloric intake was 2611.7 kcal/day (261.5 equating to 58.4 kcal/kg (10.2. Most patients (92.6% were treated with nasogastric tube feeding. The mean (SD length of stay was 3.6 weeks (1.9, and average weekly weight gain was 2.1 kg (0.8. No patients developed cardiac signs of RFS or delirium; complications included 4% peripheral oedema, 1% hypophosphatemia (<0.75 mmol/L, 7% hypomagnesaemia (<0.70 mmol/L, and 2% hypokalaemia (<3.2 mmol/L. Caloric prescription on admission was associated with developing oedema (95% CI 1.001 to 1.047; p=0.039. No statistical significance was found between electrolytes and calories provided during refeeding. Conclusion. A rapid refeeding protocol with the inclusion of phosphate supplementation can safely achieve rapid weight restoration without increased complications associated with refeeding syndrome.

  5. Factor de cielo visible y el efecto de isla de calor en Valparaíso

    Directory of Open Access Journals (Sweden)

    Claudio Carrasco

    2016-11-01

    Full Text Available La forma urbana transforma el territorio y su comportamiento climático. La morfología de la ciudad varía desde sus centros hasta su periferia, así como también varía en densidad poblacional, en el uso temporal de las edi caciones, en la presencia o ausencia de vegetación o en la densidad de transporte. Estas variables condicionan el comportamiento térmico del espacio público. A partir de la consideración de la visibilidad del cielo desde el cañón urbano se de ne el SVF (Sky View Factor, que está relacionado con el almacenamiento térmico y la ventilación del espacio de la calle. Ambas variables son fundamentales en el confort peatonal y en el calentamiento de la ciudad. En este trabajo se presentan desempeños climáticos asociados a la morfología de la ciudad de Valparaíso, ubicada en un clima mediterráneo costero. Se realizaron mediciones climáticas simultáneas en diversos lugares de la ciudad que se correlacionaron con parámetros geométricos y materiales de los lugares registrados. Se determina una estrecha relación entre morfología urbana, comportamiento térmico del espacio público y aumento de la temperatura favoreciendo el fenómeno de isla de calor (UHI. Estos valores permitirían predecir en forma más precisa las condiciones climáticas en el nivel de calle y la manera cómo afecta en el fenómeno urbano de isla de calor (UHI.

  6. 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

  7. Coordinated multitissue transcriptional and plasma metabonomic profiles following acute caloric restriction in mice.

    Science.gov (United States)

    Selman, Colin; Kerrison, Nicola D; Cooray, Anisha; Piper, Matthew D W; Lingard, Steven J; Barton, Richard H; Schuster, Eugene F; Blanc, Eric; Gems, David; Nicholson, Jeremy K; Thornton, Janet M; Partridge, Linda; Withers, Dominic J

    2006-11-27

    Caloric restriction (CR) increases healthy life span in a range of organisms. The underlying mechanisms are not understood but appear to include changes in gene expression, protein function, and metabolism. Recent studies demonstrate that acute CR alters mortality rates within days in flies. Multitissue transcriptional changes and concomitant metabolic responses to acute CR have not been described. We generated whole genome RNA transcript profiles in liver, skeletal muscle, colon, and hypothalamus and simultaneously measured plasma metabolites using proton nuclear magnetic resonance in mice subjected to acute CR. Liver and muscle showed increased gene expressions associated with fatty acid metabolism and a reduction in those involved in hepatic lipid biosynthesis. Glucogenic amino acids increased in plasma, and gene expression for hepatic gluconeogenesis was enhanced. Increased expression of genes for hormone-mediated signaling and decreased expression of genes involved in protein binding and development occurred in hypothalamus. Cell proliferation genes were decreased and cellular transport genes increased in colon. Acute CR captured many, but not all, hepatic transcriptional changes of long-term CR. Our findings demonstrate a clear transcriptional response across multiple tissues during acute CR, with congruent plasma metabolite changes. Liver and muscle switched gene expression away from energetically expensive biosynthetic processes toward energy conservation and utilization processes, including fatty acid metabolism and gluconeogenesis. Both muscle and colon switched gene expression away from cellular proliferation. Mice undergoing acute CR rapidly adopt many transcriptional and metabolic changes of long-term CR, suggesting that the beneficial effects of CR may require only a short-term reduction in caloric intake.

  8. Caloric beverages consumed freely at meal-time add calories to an ad libitum meal.

    Science.gov (United States)

    Panahi, Shirin; El Khoury, Dalia; Luhovyy, Bohdan L; Goff, H Douglas; Anderson, G Harvey

    2013-06-01

    The objective was to compare the effects of ad libitum consumption of commonly consumed meal-time beverages on energy and fluid intakes and post-meal average subjective appetite and blood glucose in healthy adults. In a randomized controlled design, 29 males and females consumed to satiation an ad libitum pizza meal with one of five beverages in unlimited amount including water (0 kcal), 1% milk (44 kcal/100 ml), regular cola (44 kcal/100 ml), orange juice (44 kcal/100 ml) and diet cola (0 kcal). Food and fluid intakes were measured at the meal. Average subjective appetite and blood glucose were measured before and for 2h after the meal. Although energy intake from pizza was similar among all beverage treatments, the amount of fluid consumed (g) varied among the beverages with intake of orange juice higher than regular and diet cola, but not different from water or milk. Meal-time ingestion of caloric beverages, milk, orange juice and regular cola, led to higher total meal-time energy intakes compared to either water or diet cola. Post-meal blood glucose area under the curve (AUC) was lower after milk than after meals with water, orange juice and regular cola and post-meal average subjective appetite AUC was lower after milk than after meals with water. Meal intakes of nutrients including protein, calcium, phosphorus, zinc, vitamins B12, A and D were higher at the meal with milk compared to the other beverages. Thus, caloric beverages consumed ad libitum during a meal add to total meal-time energy intake, but 1% milk favors a lower post-meal blood glucose and average subjective appetite score and adds to nutrient intake. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Antagonistic targeting of the histamine H3 receptor decreases caloric intake in higher mammalian species.

    Science.gov (United States)

    Malmlöf, Kjell; Hastrup, Sven; Wulff, Birgitte Schellerup; Hansen, Barbara C; Peschke, Bernd; Jeppesen, Claus Bekker; Hohlweg, Rolf; Rimvall, Karin

    2007-04-15

    The main purpose of this study was to examine the effects of a selective histamine H(3) receptor antagonist, NNC 38-1202, on caloric intake in pigs and in rhesus monkeys. The compound was given intragastrically (5 or 15 mg/kg), to normal pigs (n=7) and subcutaneously (1 or 0.1mg/kg) to obese rhesus monkeys (n=9). The energy intake recorded following administration of vehicle to the same animals served as control for the effect of the compound. In addition, rhesus monkey and pig histamine H(3) receptors were cloned from hypothalamic tissues and expressed in mammalian cell lines. The in vitro antagonist potencies of NNC 38-1202 at the H(3) receptors were determined using a functional GTPgammaS binding assay. Porcine and human H(3) receptors were found to have 93.3% identity at the amino acid level and the close homology between the monkey and human H(3) receptors (98.4% identity) was confirmed. The antagonist potencies of NNC 38-1202 at the porcine, monkey and human histamine H(3) receptors were high as evidenced by K(i)-values being clearly below 20 nM, whereas the K(i)-value on the rat H(3) receptor was significantly higher (56+/-6.0 nM). NNC 38-1202, given to pigs in a dose of 15 mg/kg, produced a significant (p<0.05) reduction (55%) of calorie intake compared with vehicle alone, (132.6+/-10.0 kcal/kgday versus 59.7+/-10.2 kcal/kgday). In rhesus monkeys administration of 0.1 and 1mg/kg decreased (p<0.05) average calorie intakes by 40 and 75%, respectively. In conclusion, the present study demonstrates that antagonistic targeting of the histamine H(3) receptor decreases caloric intake in higher mammalian species.

  10. [Caloric value and energy allocation of Chloris virgata in northeast grassland].

    Science.gov (United States)

    Guo, J; Wang, R; Wang, W

    2001-06-01

    The rules of seasonal changes in caloric values of individual plant, stem, and leaves of Chloris virgata were similar, which had two peak values from early July to early August, and then decreased gradually. Those of inflorescence assumed U shape, and had two peak values in early August and middle September, respectively. The seasonal changes in caloric values of dead standing were irregular, and the maximum value was appeared in early August. The seasonal changes in existent energy value of the aboveground parts in Chloris virgata population presented double peak curve. The two peak values were appeared in early August and early September respectively, and the maximum value was 7381.27 kJ.m-2 in early September. The energy allocation in different seasons was leaf > stem in early July, stem > leaf > dead standing in middle July, stem > leaf > inflorescence > dead standing in August, stem > inflorescence > leaf > dead standing in early September, and stem > inflorescence > dead standing > leaf in middle September. The vertical structure of energy in the aboveground parts was that the energy value gradually increased from the earth's surface to 20 cm high, and then decreased. The maximum value, which accounted for 25.75% of energy in the aboveground parts, was appeared in the layer of 10-20 cm high. In the underground parts, the energy value progressively decreased with the increase of depth, and the maximum value, which accounted for 74.21% of energy in the underground parts, was appeared in the layer of 0-10 cm depth.

  11. 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.

  12. 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.

  13. COMPARAÇÃO ENTRE TÉCNICAS NUMÉRICAS PARA A RESOLUÇÃO DO PROBLEMA DE TRANSFERÊNCIA DE CALOR EM ALIMENTOS ENLATADOS

    Directory of Open Access Journals (Sweden)

    A.D. RODRIGUES

    1998-05-01

    Full Text Available Este trabalho apresenta a comparação das técnicas de resolução numérica de Diferenças Finitas e Runge-Kutta-Gill de 4a ordem com passo de integração variável para a simulação do modelo de transferência de calor em regime transiente bidimensional em coordenadas cilíndricas e unidimensional em coordenadas esféricas, aplicado a alimentos enlatados processados em autoclave, observando-se a rapidez e a precisão de integração comparados aos perfis reais de tempo/temperatura, incluindo desvios de processo. Além disso, uma análise de sensibilidade paramétrica na difusividade térmica foi realizada na tentativa de quantificar a influência que essa propriedade possui na resolução numérica. Para tanto, foram realizados ensaios de penetração de calor em autoclave a vapor, utilizando-se latas cilíndricas de 75x90 e 100x110 contendo simulantes de alimentos com características de aquecimento por condução e convecção.This work presents a comparison of the integration quickness and precision between the techniques of numerical resolution of Finite Differences and Runge-Kutta-Gill of fourth order with variable integration pass, to do simulation of the unsteady-state heat transfer model, two-dimensional in cylindrical coordinates and one-dimensional in spherical coordinates, applied to canned foods processed in retorts, showing advantages for the technique of Runge-Kutta-Gill. It was also accomplished a parametric sensitivity analysis in the thermal diffusivity indicating a great influence of this parameter in the numerical solution. The mathematical simulation were compared with results of real heat penetration tests done in steam retort, using cylindrical cans filled with bentonite suspensions simulating foods with heat characteristics resembling heat conduction and heat convection.

  14. Effect of herbal medicine daikenchuto on oral and enteral caloric intake after liver transplantation: A multicenter, randomized controlled trial.

    Science.gov (United States)

    Kaido, Toshimi; Shinoda, Masahiro; Inomata, Yukihiro; Yagi, Takahito; Akamatsu, Nobuhisa; Takada, Yasutsugu; Ohdan, Hideki; Shimamura, Tsuyoshi; Ogura, Yasuhiro; Eguchi, Susumu; Eguchi, Hidetoshi; Ogata, Satoshi; Yoshizumi, Tomoharu; Ikegami, Toshihiko; Yamamoto, Michio; Morita, Satoshi; Uemoto, Shinji

    2018-03-20

    Postoperative early oral or enteral intake is a crucial element of the Enhanced Recovery After Surgery (ERAS) protocol. However, normal food intake or enteral feeding cannot be started early in the presence of coexisting bowel dysfunction in patients undergoing liver transplantation (LT). The aim of this multicenter, randomized, double-blinded, placebo-controlled trial was to determine the enhancement effects of the Japanese herbal medicine Daikenchuto (DKT) on oral/enteral caloric intake in patients undergoing LT. A total of 112 adult patients undergoing LT at 14 Japanese centers were enrolled. The patients were randomly assigned to receive either DKT or placebo from postoperative day (POD) 1 to 14. The primary endpoints were total oral/enteral caloric intake, abdominal distension, and pain on POD 7. The secondary endpoints included sequential changes in total oral/enteral caloric intake after LT, and portal venous flow volume and velocity in the graft. A total of 104 patients (DKT, n = 55; placebo, n = 49) were included in the analyses. There were no significant differences between the two groups in terms of primary endpoints. However, postoperative total oral/enteral caloric intake was significantly accelerated in the DKT group compared with the placebo group (P = 0.023). Moreover, portal venous flow volume (POD 10, 14) and velocity (POD 14) were significantly higher in the DKT group than in the placebo group (P = 0.047, P = 0.025, P = 0.014, respectively). Postoperative administration of DKT may enhance total oral/enteral caloric intake and portal venous flow volume and velocity after LT and favorably contribute to the performance of the ERAS protocol. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Acute and short-term effects of caloric restriction on metabolic profile and brain activation in obese, postmenopausal women.

    Science.gov (United States)

    Jakobsdottir, S; van Nieuwpoort, I C; van Bunderen, C C; de Ruiter, M B; Twisk, J W R; Deijen, J B; Veltman, D J; Drent, M L

    2016-11-01

    Early anthropometric and metabolic changes during a caloric-restricted diet in obese postmenopausal women and correlations between these factors with activity in brain areas involved in processing of visual food related stimuli were investigated. An 8-week prospective intervention study of 18 healthy postmenopausal women, with a body mass index of 30-35 kg m -2 . The first 2 weeks subjects were on an isocaloric diet and 4 weeks on a 1000 kcal restricted diet followed by 2 weeks on an isocaloric diet. Anthropometric and laboratory analyses were performed weekly during the isocaloric diet and three times a week during the caloric-restricted diet. Functional magnetic resonance imaging scans were obtained before and after the caloric restriction in four separate sessions (fasting or sated). Generalized Estimating Equations analysis was used for data analysis. A mean weight loss of 4.2±0.5 kg (4.8%) and a 4.2±0.4 cm decline in waist circumference were achieved. In the first week of caloric restriction, triglyceride, leptin, resistin and adiponectin levels as well as systolic blood pressure decreased and insulin-like growth factor-binding protein 1 levels increased. During and after weight loss, a significant increase in ghrelin levels was observed. Before weight loss, increased activation of the right amygdala was seen in response to food stimuli, and free fatty acids and glucose correlated with activity in various areas involved in food reward processing. After weight loss, fasting ghrelin and sated leptin levels correlated with activity in these areas. Already in the first week of caloric restriction in obese postmenopausal women, various favourable metabolic changes occur before clinically relevant weight loss is achieved. Activity in the amygdala region and correlations of metabolic factors with activity in brain areas involved in food reward processing differ substantially before and after weight loss.

  16. The impact of exercise training compared to caloric restriction on hepatic and peripheral insulin resistance in obesity.

    Science.gov (United States)

    Coker, Robert H; Williams, Rick H; Yeo, Sophie E; Kortebein, Patrick M; Bodenner, Don L; Kern, Philip A; Evans, William J

    2009-11-01

    It has been difficult to distinguish the independent effects of caloric restriction versus exercise training on insulin resistance. Utilizing metabolic feeding and supervised exercise training, we examined the influence of caloric restriction vs. exercise training with and without weight loss on hepatic and peripheral insulin resistance. Thirty-four obese, older subjects were randomized to: caloric restriction with weight loss (CR), exercise training with weight loss (EWL), exercise training without weight loss (EX), or controls. Based on an equivalent caloric deficit in EWL and CR, we induced matched weight loss. Subjects in the EX group received caloric compensation. Combined with [6,6(2)H(2)]glucose, an octreotide, glucagon, multistage insulin infusion was performed to determine suppression of glucose production (SGP) and insulin-stimulated glucose disposal (ISGD). Computed tomography scans were performed to assess changes in fat distribution. Body weight decreased similarly in EWL and CR, and did not change in EX and controls. The reduction in visceral fat was significantly greater in EWL (-71 +/- 15 cm(2)) compared to CR and EX. The increase in SGP was also almost 3-fold greater (27 +/- 2%) in EWL. EWL and CR promoted similar improvements in ISGD [+2.5 +/- 0.4 and 2.4 +/- 0.9 mg x kg fat-free mass (FFM)(-1) x min(-1)], respectively. EWL promoted the most significant reduction in visceral fat and the greatest improvement in SGP. Equivalent increases in ISGD were noted in EWL and CR, whereas EX provided a modest improvement. Based on our results, EWL promoted the optimal intervention-based changes in body fat distribution and systemic insulin resistance.

  17. Control Multivariable por Desacoplo

    Directory of Open Access Journals (Sweden)

    Fernando Morilla

    2013-01-01

    Full Text Available Resumen: La interacción entre variables es una característica inherente de los procesos multivariables, que dificulta su operación y el diseño de sus sistemas de control. Bajo el paradigma de Control por desacoplo se agrupan un conjunto de metodologías, que tradicionalmente han estado orientadas a eliminar o reducir la interacción, y que recientemente algunos investigadores han reorientado con objetivos de solucionar un problema tan complejo como es el control multivariable. Parte del material descrito en este artículo es bien conocido en el campo del control de procesos, pero la mayor parte de él son resultados de varios años de investigación de los autores en los que han primado la generalización del problema, la búsqueda de soluciones de fácil implementación y la combinación de bloques elementales de control PID. Esta conjunción de intereses provoca que no siempre se pueda conseguir un desacoplo perfecto, pero que sí se pueda conseguir una considerable reducción de la interacción en el nivel básico de la pirámide de control, en beneficio de otros sistemas de control que ocupan niveles jerárquicos superiores. El artículo resume todos los aspectos básicos del Control por desacoplo y su aplicación a dos procesos representativos: una planta experimental de cuatro tanques acoplados y un modelo 4×4 de un sistema experimental de calefacción, ventilación y aire acondicionado. Abstract: The interaction between variables is inherent in multivariable processes and this fact may complicate their operation and control system design. Under the paradigm of decoupling control, several methodologies that traditionally have been addressed to cancel or reduce the interactions are gathered. Recently, this approach has been reoriented by several researchers with the aim to solve such a complex problem as the multivariable control. Parts of the material in this work are well known in the process control field; however, most of them are

  18. Análisis de perfiles de temperatura durante el proceso de calentamiento de frutas por microondas

    OpenAIRE

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

    2017-01-01

    La transferencia de energía durante el proceso de calentamiento por microondas de frutas fue estudiada teórica y experimentalmente mediante el modelado y simulación numérica. Con el fin de describir los fenómenos de transporte puestos en juego durante el proceso de calentamiento, en primer lugar se planteó el balance microscópico de energía con propiedades globales en función de la temperatura; la generación interna de calor debida a la interacción del alimento con la energía electromagnética...

  19. Absorción de energía en nanopartículas de magnetita mediante calentamiento por microondas | Energy absoption in magnetites nanoparticles by microwave heating

    Directory of Open Access Journals (Sweden)

    Díckar Bonyuet

    2017-10-01

    Full Text Available La terapia de hipertermia es el proceso de tratar el cáncer con la aplicación de calor, elevando la temperatura de las células entre 40º a 43ºC, destruyendo las células cancerosas. El problema de esta técnica es la generación y el control del calor dentro de las células tumorales sin dañar el tejido sano circundante. Las células cancerosas tienen típicamente diámetros de 10 a 100 micrones y absorben partículas magnéticas. En el presente trabajo, se empleó el método de calentamiento por microondas de nanopartículas de magnetita. Este método proporciona un rápido calentamiento volumétrico a un medio absorbente. Aplicando el enfoque de balance de energía de Holzwarth et al. (1998, se efectuó un ajuste no lineal de los datos para obtener las velocidades de pérdida de calor y absorción de energía. Finalmente se comparan los resultados con los encontrados por Kim et al. (2005.

  20. Data mining to estimate broiler mortality when exposed to heat wave Mineração de dados e estimativa da mortalidade alta de frangos quando expostos a onda de calor

    Directory of Open Access Journals (Sweden)

    Marcos Martinez Vale

    2008-01-01

    Full Text Available Heat waves usually result in losses of animal production since they are exposed to thermal stress inducing an increase in mortality and consequent economical losses. Animal science and meteorological databases from the last years contain enough data in the poultry production business to allow the modeling of mortality losses due to heat wave incidence. This research analyzes a database of broiler production associated to climatic data, using data mining techniques such as attribute selection and data classification (decision tree to model the impact of heat wave incidence on broiler mortality. The temperature and humidity index (THI was used for screening environmental data. The data mining techniques allowed the development of three comprehensible models for estimating specifically high mortality during broiler production. Two models yielded a classification accuracy of 89.3% by using Principal Component Analysis (PCA and Wrapper feature selection approaches. Both models obtained a class precision of 0.83 for classifying high mortality. When the feature selection was made by the domain experts, the model accuracy reached 85.7%, while the class precision of high mortality was 0.76. Meteorological data and the calculated THI from meteorological stations were helpful to select the range of harmful environmental conditions for broilers 29 and 42 days old. The data mining techniques were useful for building animal production models.As ondas de calor provocam perdas na produção animal pela sua exposição ao estresse por calor aumentando a mortalidade, e consequentemente, perdas econômicas. Bancos de dados zootécnicos e meteorológicos históricos podem conter informações que permitem modelar a mortalidade de frangos devido à incidência de ondas de calor. O objetivo foi analisar bancos de dados de frangos de corte associados a dados meteorológicos utilizando técnicas de mineração de dados, seleção de atributos e classificação (

  1. Producción de energía por combustión de basuras en Bogotá

    Directory of Open Access Journals (Sweden)

    Abel Morales Gilede

    1984-09-01

    Full Text Available Este estudio tiene por objeto hacer un avalúo de la posibilidad de producir energía por medio de la incineración de las basuras provenientes de la ciudad de Bogotá. El estudio se desarrolló con base en la información existente. Elaborada especialmente por EDIS. Por contratos realizados por esta entidad con diferentes compañías y con la colaboración del Instituto de Investigaciones Tecnológicas y complementada por los Laboratorios de la Universidad Nacional. Con base en estos estudios se obtuvo la siguiente información: - Producción total de basuras por zonas. - Características físicas y químicas de las basuras. - Poder calorífico de las basuras. De acuerdo con la anterior información se procedió a calcular la capacidad de generación eléctrica que se obtendría al quemar estas basuras.

  2. Establishment of the Processes of Absorption and Diffusion of Systemic Insecticides in Populus Euramericana Dode Guinier ''Robusta''; L'etablissement des processus d'absorption et diffusion des insecticides systemiques au Populus x Euramericana Dode Guinier ''Robista; Opredelenie protsessov pogloshcheniya i diffuzii somaticheskikh insektitsidov u Populus x Euramerican a Dode Guinier ''Robusta''; Determinacion de los procesos de absorcion y difusion de los insecticidas sistemicos en el Populus x Euramericana Dope Guinier ''Robusta''

    Energy Technology Data Exchange (ETDEWEB)

    Catrina, I.; Popa, A.; Constantinesco, V.; Constantinesco, O.; Constantinesco, El.; Hulula, C. [Institut de Recherches Forestieres de Bucarest, Bucharest (Romania)

    1963-09-15

    d'insecticide marque, les plants ont ete soumis a l'analyse radiometrique. Dans les experiences en laboratoire, l'insecticide a ete accumule en grandes quantites dans les feuilles et en plus petites quantites dans le bois. Tant en laboratoire qu'en pepiniere, l'insecticide a ete accumule en plus grande proportion dans les feuilles. Pourtant, on constate une augmentation importante des accumulations d'insecticide dans les rameaux et dans le bois de la tige, surtout au bout des plants, dans l'experience en pepiniere. En general, l'accumulation d'insecticide a ete de 1,65 mg/g substance verte en pepiniere, contre 0,24 mg/g en pots. Il en resulte que; dans les conditions de terrain, les plants de peuplier Robusta de 2 ans, pendant le temos sec, peuvent mobiliser le Dipterex administre en solution aqueuse a raison de 9,3% de la quantite versee dans le sol, contre 1,35% dans les experiences en laboratoire. L'administration des solutions sur les feuilles par pulverisation a un rendement faible d'absorption de l'insecticide, grace aussi bien au mecanisme difficile d'absorption des feuilles qu'au lavage de l'insecticide par l'eau de pluie, la rosee et le brouillard. On a decele une grande quantite d'insecticide sur le sol; c'est pourquoi les auteurs considerent que la methode d'administration des solutions d'insecticides systemiques dans le sol doit etre adoptee en priorite dans la lutte contre les ennemis des essences ligneuses. (author) [Spanish] Losinsecticidas organofosforicos de accion indirecta penetran en la corriente de savia de las plantas y actuan asi sobre los insectos que viven en el lefio o en la zona cambial situada entre el lefio y la corteza. Hasta la aparicion de estos nuevos insecticidas era casi imposible luchar por medios quimicos contra los insectos xilofagos del tronco de los arboles. Para estudiar el mecanismo de absorcion, difusion y localizacion de los insecticidas de accion indirecta en las distintas especies de alamos y sauces que suelen verse

  3. Looking at the label and beyond: the effects of calorie labels, health consciousness, and demographics on caloric intake in restaurants.

    Science.gov (United States)

    Ellison, Brenna; Lusk, Jayson L; Davis, David

    2013-02-08

    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. 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 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. 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 little for those consumers who were already

  4. 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.

  5. 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 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.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.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, data suggest that HexCer/LacCers are important mediators of cellular

  6. Refrigeración local de vehículos con calor excedente

    OpenAIRE

    Matarazzo Zinoni, Gustavo

    2014-01-01

    RESUMEN: Existe una gran cantidad de energía que normalmente desperdiciamos cuando trabajamos con máquinas térmicas tales como los motores de nuestros vehículos. ¿Por qué no empezamos a aprovechar mejor esta energía? Los gases de escape del motor de nuestro automóvil salen con una temperatura y una velocidad muy alta, es decir, salen con mucha energía. ¿Por qué la desperdiciamos? Por otro lado, cuando encendemos el aire acondicionado de nuestro vehículo quitamos eficiencia al motor porque tom...

  7. Mathematical model for heat loss calculation through a window; Modelo para el calculo de la perdida de calor por una ventana

    Energy Technology Data Exchange (ETDEWEB)

    Fissore Sch, Adelqui; Cuevas B, Cristian [Universidad de Concepcion (Chile). Facultad de Ingenieria. Dept. de Ingenieria Mecanica]. E-mail: afissore@udec.cl; ccuevas@udec.cl

    2000-07-01

    In the present work a semi-empirical model for heat loss by convection at an indoor window surface with curtain or blind is given. With this model, the convection heat transfer coefficient and temperature of the air at confined space between the curtain and the glass can be calculated. The curtain was modeled with a paper due to the low thermal inertia that it has. The model is based on experimental data obtained for four separations between the paper and the window. Data from numerical simulation program are also used. (author)

  8. Laser desensitization of austenitic stainless steel weld AHZ. Desensibilizacion con Laser de la zona afectada por el calor (ZAC) en aceros inoxidables austeniticos

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.H.; Kim, K.C.; Chang, R.W. (Welding Research Center Research Institute of Industrial Science and Technology, Pohang (Korea, Republic of))

    1994-01-01

    This paper addressed the fundamental understanding of sensitization phenomena in the weld HAZ of austenitic stainless steel and a method of desensitization utilizing LASER, without degradation of other corrosion resistance (pitting resistance). Sensitization in the weld HAZ was due to a formation of CR depleted zone along grain boundaries and twin boundaries by precipitation of Cr[sub 2]3C[sub 6] which contains 70-80% Cr and a small amount of Fe having a cubic-cubic relationship with the austenite matrix. Common morphologies of carbides were found to be of bar and globular shapes. As the holding time increased, carbides with coarsened globular (iodomorph) and dendrite shapes were also found. However, there was no significant variation in the composition of carbides and width of the Cr depleted zone with morphology. Laser desensitization could be obtained with a proper choice of the beam power and travel speed under a constant beam size. As long as the beam density reached a critical amount, carbides and Cr depleted zone completed zone completely disappeared. The critical travel speed increased with higher beam power, but was constant regardless of the original degree of sensitization. Pitting resistance of the LASER desensitized base metal and HAZ appeared to be far superior to that found in the sensitized condition. The protection potential in the hysteresis loop test was very sensitive to the degree of sensitization, revealing that the protection potential was dependent upon the propagation of the pits through the Cr depleted grain boundaries. (Author) 10 refs.

  9. 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.

  10. The effect of brand and caloric information on flavor perception and food consumption in restrained and unrestrained eaters.

    Science.gov (United States)

    Cavanagh, Kevin V; Kruja, Blina; Forestell, Catherine A

    2014-11-01

    The goal of the current study was to determine whether provision of brand and caloric information affects sensory perception and consumption of a food in restrained (n=84) and unrestrained eaters (n=104). Using a between-subjects 2 × 2 × 3 design, female restrained and unrestrained eaters were asked to taste and rate a cookie that was labeled with a brand associated with healthful eating (Kashi(®)) or one associated with unhealthful eating (Nabisco(®)). Additionally, some participants were presented with a nutrition label alongside the brand name indicating that one serving contained 130 calories (Low-Calorie Condition), or 260 calories (High-Calorie Condition). The remaining participants were not shown a nutrition label (No Label Condition). Results indicated that those in the No Label or the High-Calorie Condition perceived the healthful branded cookie to have a better flavor than those who received the unhealthful branded cookie regardless of their restraint status. However, restrained eaters in the No Label Condition consumed more of the healthful than the unhealthful branded cookie, whereas those in the Low-Calorie Condition consumed more of the unhealthful than the healthful branded cookie. In contrast, unrestrained eaters ate more of the healthful branded cookie regardless of the caloric information provided. Thus, although restrained and unrestrained eaters' perceptions are similarly affected by branding and caloric information, brands and caloric information interact to affect restrained eaters' consumption. This study reveals that labeling foods as low calorie may create a halo effect which may lead to over-consumption of these foods in restrained eaters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Contribution by Lazare and Sadi Carnot to the caloric theory of heat and its inspirative role in thermodynamics

    Czech Academy of Sciences Publication Activity Database

    Šesták, Jaroslav; Mareš, Jiří J.; Hubík, Pavel; Proks, I.

    2009-01-01

    Roč. 97, č. 2 (2009), s. 679-683 ISSN 1388-6150 R&D Projects: GA AV ČR IAA1010404; GA AV ČR IAA100100639 Institutional research plan: CEZ:AV0Z10100521 Keywords : caloric as entropy * Carnot * efficiency * history * thermal analysis * thermodynamics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.587, year: 2009

  12. 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.

  13. 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.

  14. Maintenance of cellular ATP level by caloric restriction correlates chronological survival of budding yeast

    International Nuclear Information System (INIS)

    Choi, Joon-Seok; Lee, Cheol-Koo

    2013-01-01

    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

  15. [Developing indices for caloric restriction related to World War II--a pilot study].

    Science.gov (United States)

    Vin-Raviv, Neomi; Dekel, Rachel; Barchana, Micha; Linn, Shi; Keinan-Boker, Lital

    2011-04-01

    The vast numbers of studies regarding caloric restriction (CR) and breast cancer risk are based on war-related extreme situations. Studying the impact of CR in Jews during World War II (WW II) is challenging due to its variance and duration. To develop novel research tools in order to assess CR exposure in Jews that occurred more than 60 years ago during WW II. A pilot study based on Israeli women born in Europe in 1926-45, who lived there during WWII. Primary incident breast cancer patients and population-based controls were interviewed using a detailed questionnaire referring to demographic, obstetric factors and WW II experiences. Exposure to WWII-related CR was assessed by several proxy variables based on this information. The individual hunger score was higher in the exposed cases [mean score 141.06 vs. 130.07 in the controls). The same trend was observed for self perceived hunger score (mean score 2.75 in cases vs. 2.40 in controls) and hunger symptoms score (4.89 vs. 3.56, respectively). The novel research tools are appropriate for comparative assessment of CR exposure in case control studies.

  16. Higher Caloric Refeeding Is Safe in Hospitalised Adolescent Patients with Restrictive Eating Disorders

    Science.gov (United States)

    Parker, Elizabeth K.; Faruquie, Sahrish S.; Anderson, Gail; Gomes, Linette; Kennedy, Andrew; Wearne, Christine M.; Kohn, Michael R.; Clarke, Simon D.

    2016-01-01

    Introduction. This study examines weight gain and assesses complications associated with refeeding hospitalised adolescents with restrictive eating disorders (EDs) prescribed initial calories above current recommendations. Methods. Patients admitted to an adolescent ED structured “rapid refeeding” program for >48 hours and receiving ≥2400 kcal/day were included in a 3-year retrospective chart review. Results. The mean (SD) age of the 162 adolescents was 16.7 years (0.9), admission % median BMI was 80.1% (10.2), and discharge % median BMI was 93.1% (7.0). The mean (SD) starting caloric intake was 2611.7 kcal/day (261.5) equating to 58.4 kcal/kg (10.2). Most patients (92.6%) were treated with nasogastric tube feeding. The mean (SD) length of stay was 3.6 weeks (1.9), and average weekly weight gain was 2.1 kg (0.8). No patients developed cardiac signs of RFS or delirium; complications included 4% peripheral oedema, 1% hypophosphatemia (refeeding. Conclusion. A rapid refeeding protocol with the inclusion of phosphate supplementation can safely achieve rapid weight restoration without increased complications associated with refeeding syndrome. PMID:27293884

  17. 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

  18. Evaluation of dysphagia risk, nutritional status and caloric intake in elderly patients with Alzheimer's

    Science.gov (United States)

    Goes, Vanessa Fernanda; Mello-Carpes, Pâmela Billig; de Oliveira, Lilian Oliveira; Hack, Jaqueline; Magro, Marcela; Bonini, Juliana Sartori

    2014-01-01

    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. PMID:26107841

  19. 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.

  20. Caloric restriction increases ketone bodies metabolism and preserves blood flow in aging brain.

    Science.gov (United States)

    Lin, Ai-Ling; Zhang, Wei; Gao, Xiaoli; Watts, Lora

    2015-07-01

    Caloric restriction (CR) has been shown to increase the life span and health span of a broad range of species. However, CR effects on in vivo brain functions are far from explored. In this study, we used multimetric neuroimaging methods to characterize the CR-induced changes of brain metabolic and vascular functions in aging rats. We found that old rats (24 months of age) with CR diet had reduced glucose uptake and lactate concentration, but increased ketone bodies level, compared with the age-matched and young (5 months of age) controls. The shifted metabolism was associated with preserved vascular function: old CR rats also had maintained cerebral blood flow relative to the age-matched controls. When investigating the metabolites in mitochondrial tricarboxylic acid cycle, we found that citrate and α-ketoglutarate were preserved in the old CR rats. We suggest that CR is neuroprotective; ketone bodies, cerebral blood flow, and α-ketoglutarate may play important roles in preserving brain physiology in aging. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Severe caloric restriction in young women during World War II and subsequent breast cancer risk.

    Science.gov (United States)

    Vin-Raviv, N; Barchana, M; Linn, S; Keinan-Boker, L

    2012-10-01

    The objective of the study was to examine the impact of WWII-related caloric restriction (CR) on subsequent breast cancer (BC) risk based on individual exposure experiences and whether this effect was modified by age at exposure. We compared 65 breast cancer patients diagnosed between 2005-2010 to 200 controls without breast cancer who were all members of various organizations for Jewish WWII survivors in Israel. All participants were Jewish women born in Europe prior to 1945 who lived at least 6 months under Nazi rule during WWII and immigrated to Israel after the war. We estimated CR using a combined index for hunger and used logistic regression models to estimate the association between CR and BC, adjusting for potential confounders. Women who were severely exposed to hunger had an increased risk of BC (OR=5.0, 95% CI= 2.3-10.8) compared to women who were mildly exposed. The association between CR and BC risk was stronger for women who were exposed at a younger age (0-7 years) compared to the risk of BC in women exposed at ≥ 14 years (OR= 2.8, 95% CI=1.3-6.3). Severe exposure to CR is associated with a higher risk for BC decades later, and may be generalized to other cases of severe starvation during childhood that may have long-term effects on cancer in adulthood. © 2012 Blackwell Publishing Ltd.

  2. 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.

  3. Central de producción de calor - Madrid – España

    Directory of Open Access Journals (Sweden)

    Laorden Jiménez, J.

    1973-10-01

    Full Text Available The Heat Production Station of the University City Hospital in Madrid is described, after several years operation. The Station is equipped for an output of 13,000,000 kcal/hr, for heating; 1,000,000 kcal/hr, for hospital hot water, and 3,200,000 kcal/hr, for steam at 5 kp/cm2. The different alternatives are presented and the general outline of the solution chosen, as well as a comprehensive list of the materials used.Se describe la Central de Producción de Calor del Hospital Clínico de la Ciudad Universitaria de Madrid, después de algunos años de funcionamiento. La Central está preparada para una producción de 13.000.000 de kcal/h, para calefacción; 1.000.000 de kilocalorías/h, para agua caliente sanitaria, y 3.200.000 kcal/h, para vapor a 5 kp/cm2. Se presentan las diversas alternativas y el esquema general de la solución elegida, así como una extensa relación de ios materiales empleados.

  4. Dynamics of nucleus-nucleus collisions up to 100 MeV/u and caloric curve

    International Nuclear Information System (INIS)

    Peter, J.; Angelique, J.C.; Auger, G.

    1997-01-01

    Using the 4π multidetector array Mur + Tonneau at GANIL made it possible to determine that, at incidence energy 35-95 MeV/u, the fusion (or one main source) cross section is very small in nearly symmetrical light and medium systems. Dissipative binary collisions accompanied by mid-rapidity (participant) emission were found to dominate at all impact parameters. The excitation energy of the reconstructed quasi-projectile was obtained via calorimetry and reaches high values. Using the 4π array INDRA several new features of mid-rapidity emission were revealed: the isotopic composition, mean transverse momentum and apparent temperature do not vary with the impact parameter, whereas the number of emitted nucleons increases with decreasing impact parameter. Mid-rapidity products are more n-rich than quasi-projectile products. Hot quasi-projectiles formed in two reactions were used to study the caloric curve. The apparent temperatures were obtained from several double isotopic yield ratios and slopes of kinetic energy spectra at excitation energy per nucleon ranging up to 24 MeV. Different thermometers give different values, but all of them increase steadily with excitation energy. These data can be explained by calculations assuming a steady increase of the initial temperature with excitation energy, without a plateau which was claimed as evidence for a liquid-gas phase transition. (authors)

  5. Measuring aging rates of mice subjected to caloric restriction and genetic disruption of growth hormone signaling.

    Science.gov (United States)

    Koopman, Jacob J E; van Heemst, Diana; van Bodegom, David; Bonkowski, Michael S; Sun, Liou Y; Bartke, Andrzej

    2016-03-01

    Caloric restriction and genetic disruption of growth hormone signaling have been shown to counteract aging in mice. The effects of these interventions on aging are examined through age-dependent survival or through the increase in age-dependent mortality rates on a logarithmic scale fitted to the Gompertz model. However, these methods have limitations that impede a fully comprehensive disclosure of these effects. Here we examine the effects of these interventions on murine aging through the increase in age-dependent mortality rates on a linear scale without fitting them to a model like the Gompertz model. Whereas these interventions negligibly and non-consistently affected the aging rates when examined through the age-dependent mortality rates on a logarithmic scale, they caused the aging rates to increase at higher ages and to higher levels when examined through the age-dependent mortality rates on a linear scale. These results add to the debate whether these interventions postpone or slow aging and to the understanding of the mechanisms by which they affect aging. Since different methods yield different results, it is worthwhile to compare their results in future research to obtain further insights into the effects of dietary, genetic, and other interventions on the aging of mice and other species.

  6. Caloric Restriction-Induced Extension of Chronological Lifespan Requires Intact Respiration in Budding Yeast.

    Science.gov (United States)

    Kwon, Young-Yon; Lee, Sung-Keun; Lee, Cheol-Koo

    2017-04-01

    Caloric restriction (CR) has been shown to extend lifespan and prevent cellular senescence in various species ranging from yeast to humans. Many effects of CR may contribute to extend lifespan. Specifically, CR prevents oxidative damage from reactive oxygen species (ROS) by enhancing mitochondrial function. In this study, we characterized 33 single electron transport chain (ETC) gene-deletion strains to identify CR-induced chronological lifespan (CLS) extension mechanisms. Interestingly, defects in 17 of these 33 ETC gene-deleted strains showed loss of both respiratory function and CR-induced CLS extension. On the contrary, the other 16 respiration-capable mutants showed increased CLS upon CR along with increased mitochondrial membrane potential (MMP) and intracellular adenosine triphosphate (ATP) levels, with decreased mitochondrial superoxide generation. We measured the same parameters in the 17 non-respiratory mutants upon CR. CR simultaneously increased MMP and mitochondrial superoxide generation without altering intracellular ATP levels. In conclusion, respiration is essential for CLS extension by CR and is important for balancing MMP, ROS, and ATP levels.

  7. Metabolomics Reveals Metabolically Healthy and Unhealthy Obese Individuals Differ in their Response to a Caloric Challenge.

    Directory of Open Access Journals (Sweden)

    Flavia Badoud

    Full Text Available To determine if metabolically healthy obese (MHO individuals have a different metabolic response to a standardized diet compared to lean healthy (LH and metabolically unhealthy obese (MUO individuals.Thirty adults (35-70 yrs were classified as LH, MHO, and MUO according to anthropometric and clinical measurements. Participants consumed a standardized high calorie meal (~1330 kcal. Blood glucose and insulin were measured at fasting, and 15, 30, 60, 90 and 120 min postprandially. Additional blood samples were collected for the targeted analysis of amino acids (AAs and derivatives, and fatty acids (FAs.The postprandial response (i.e., area under the curve, AUC for serum glucose and insulin were similar between MHO and LH individuals, and significantly lower than MUO individuals (p < 0.05. Minor differences were found in postprandial responses for AAs between MHO and MUO individuals, while three polyunsaturated FAs (linoleic acid, γ-linolenic acid, arachidonic acid showed smaller changes in serum after the meal in MHO individuals compared to MUO. Fasting levels for various AAs (notably branched-chain AA and FAs (e.g., saturated myristic and palmitic acids were found to correlate with glucose and insulin AUC.MHO individuals show preserved insulin sensitivity and a greater ability to adapt to a caloric challenge compared to MUO individuals.

  8. 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.

  9. Quality in the organizations (enterprises and institutions of production and of services). Validation of the determination by atomic absorption of sodium and potassium in acid rain; Calidad de las organizaciones (empresas e instituciones de produccion y de servicios). Validacion de la determinacion por absorcion atomica de sodio y potasio en lluvia acida

    Energy Technology Data Exchange (ETDEWEB)

    Arreola T, D.L

    2005-07-01

    The present work is focused to the environmental area and in specific to the validation of an analytical method by means of one of the techniques more used for the determination of metals, the atomic absorption spectrophotometry. Applied to the study of the acid rain and its diverse forms in the nature. As well as their consequences and the role that the man carries out in the contribution toward this phenomenon. To approach the following text it will be mention shortly how is distributed, beginning with the introduction that is about the importance of the role of the acid rain, its effects and repercussions in the environment. In the first chapter the points that we should be evaluated to carry out a validation are analyzed. Being the main ones, the precision, accuracy, lineal interval, among others. Continuing in the second chapter with the foundation study, equipment and interferences of the atomic absorption spectrophotometry technique. The last chapter contains the experimental part, continuing for each evaluated point, from the experimental development, results and its analysis. (Author)

  10. Validation of the methodology for determining As, Sb, Hg, and Se in the water supply in Tudela, Navarra, spain, by atomic absorption; Validacion de la metodologia para la determinacion de As, Sb, Hg, y Se en aguas de abastecimiento a Tudela (Navarra) por absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Gale, M. A.; Cebrian, N.; Ormad, P.; Ovelleiro, J. L.

    2002-07-01

    In compliance with the current regulations on water quality, an analytical methodology has been put in place in the laboratory of the waste water treatment plant in Tudela, Navarre (Spain) to monitor As, Sb, Hg, and Se in the water going into the public water supply. The technique used to monitor these elements is atomic absorption spectrometry, As, Sb, Se are determined by the generation of hydrides and Hg by the generation of cold vapour. In addition, in order to ensure the authenticity of the results, the methodology employed has been validated by a study of the following technical characteristics: linearity, work interval, sensitivity, precision and accuracy. Extremely satisfactory results were obtained in all cases. A linear range between 0 and 1000 mg/l for all four elements and extremely low detection and quantification limits (less than 1 mg/l) were found. In the study of the method's accuracy, the C. V. s were below the legally established minima and the method was found to be very accurate. (Author) 18 refs.

  11. Combinación de sistemas de flujo de baja y alta presion para la determinacion de Mg, Ca y Sr en salmueras por espectrofotometria de absorcion atomica con llama Combination of low- and high-pressure flow systems for the determination of Mg, Ca and Sr in brines by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    José Neira

    2001-04-01

    Full Text Available This article describes the combination of low- and high-pressure flow systems for the determination of Magnesium, Calcium and Strontium by flame atomic absorption spectrometry (FAAS. In the low-pressure system a short C-18 RP column (length 0,5 cm was utilized for the preconcentration/matrix separation step, xylenol orange was used as chelating agent and tetrabutylamonium acetate for ion pair formation. The hydraulic high pressure nebulization (HHPN was used for sample transport and sample introduction in the high pressure system. The repeatabilities and detection limits for Mg, Ca and Sr were determined and compared with those obtained by pneumatic nebulization (PN. The results show that the detection limits obtained using the HHPN for Mg, Ca and Sr are between 1.5 to 2 times better than those obtained by PN when the signal transient was measured in area. The system presented a sampling frequency of 130 h-1 for direct determination of Mg, Ca or Sr in samples of saturated sodium chloride used in the production of chlorine and sodium hydroxide.

  12. [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.

  13. Nonnutritive, Low Caloric Substitutes for Food Sugars: Clinical Implications for Addressing the Incidence of Dental Caries and Overweight/Obesity

    Directory of Open Access Journals (Sweden)

    Michael W. Roberts

    2012-01-01

    Full Text Available Caries and obesity are two common conditions affecting children in the United States and other developed countries. Caries in the teeth of susceptible children have often been associated with frequent ingestion of fermentable sugars such as sucrose, fructose, glucose, and maltose. Increased calorie intake associated with sugars and carbohydrates, especially when associated with physical inactivity, has been implicated in childhood obesity. Fortunately, nonnutritive artificial alternatives and non-/low-caloric natural sugars have been developed as alternatives to fermentable sugars and have shown promise in partially addressing these health issues. Diet counseling is an important adjunct to oral health instruction. Although there are only five artificial sweeteners that have been approved as food additives by the Food and Drug Administration (FDA, there are additional five non-/low caloric sweeteners that have FDA GRAS (Generally Recognized as Safe designation. Given the health impact of sugars and other carbohydrates, dental professionals should be aware of the nonnutritive non-/low caloric sweeteners available on the market and both their benefits and potential risks. Dental health professionals should also be proactive in helping identify patients at risk for obesity and provide counseling and referral when appropriate.

  14. Sweet taste of saccharin induces weight gain without increasing caloric intake, not related to insulin-resistance in Wistar rats.

    Science.gov (United States)

    Foletto, Kelly Carraro; Melo Batista, Bruna Aparecida; Neves, Alice Magagnin; de Matos Feijó, Fernanda; Ballard, Cíntia Reis; Marques Ribeiro, Maria Flávia; Bertoluci, Marcello Casaccia

    2016-01-01

    In a previous study, we showed that saccharin can induce weight gain when compared with sucrose in Wistar rats despite similar total caloric intake. We now question whether it could be due to the sweet taste of saccharin per se. We also aimed to address if this weight gain is associated with insulin-resistance and to increases in gut peptides such as leptin and PYY in the fasting state. In a 14 week experiment, 16 male Wistar rats received either saccharin-sweetened yogurt or non-sweetened yogurt daily in addition to chow and water ad lib. We measured daily food intake and weight gain weekly. At the end of the experiment, we evaluated fasting leptin, glucose, insulin, PYY and determined insulin resistance through HOMA-IR. Cumulative weight gain and food intake were evaluated through linear mixed models. Results showed that saccharin induced greater weight gain when compared with non-sweetened control (p = 0.027) despite a similar total caloric intake. There were no differences in HOMA-IR, fasting leptin or PYY levels between groups. We conclude that saccharin sweet taste can induce mild weight gain in Wistar rats without increasing total caloric intake. This weight gain was not related with insulin-resistance nor changes in fasting leptin or PYY in Wistar rats. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The association between measurement sites of visceral adipose tissue and cardiovascular risk factors after caloric restriction in obese Korean women.

    Science.gov (United States)

    Lee, Hye-Ok; Yim, Jung-Eun; Lee, Jeong-Sook; Kim, Young-Seol; Choue, Ryowon

    2013-02-01

    Quantities as well as distributions of adipose tissue (AT) are significantly related to cardiovascular disease (CVD) risk factors and can be altered with caloric restriction. This study investigated which cross-sectional slice location of AT is most strongly correlated with changes in CVD risk factors after caloric restriction in obese Korean women. Thirty-three obese pre-menopausal Korean women (32.4 ± 8.5 yrs, BMI 27.1 ± 2.3 kg/m(2)) participated in a 12 weeks caloric restriction program. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were measured using computed tomography (CT) scans at the sites of L2-L3, L3-L4, and L4-L5. Fasting serum levels of glucose, insulin, triglyceride, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), leptin and homeostasis model assessment-insulin resistance (HOMA-IR) were observed. Pearson's partial correlation coefficients were used to assess the relationship between AT measurement sites and changes in CVD risk factors after calorie restriction. When calories were reduced by 350 kcal/day for 12 weeks, body weight (-2.7%), body fat mass (-8.2%), and waist circumference (-5.8%) all decreased (P restriction, serum levels of glucose (-4.6%), TC (-6.2%), LDL-C (-5.3%), leptin (-17.6%) and HOMA-IR (-18.2%) decreased significantly (P restriction.

  16. Estudio de la transferencia de calor en la etapa de cocido en la elaboración de aceitunas verdes al estilo sevillano

    Directory of Open Access Journals (Sweden)

    Tarrado-Castellarnau, M.

    2013-09-01

    Full Text Available This article describes for the first time at the industrial level the temperature rise that occurs inside the processing tank during the lye treatment. Relationships between variables that define the lye treatment have been determined from the study of the thermal characteristics of this process. The initial temperature influences other variables of this treatment, such as its duration or the slope of the linear increase of temperature produced. The study estates that this generation of heat can be principally caused by the alkaline hydrolysis reactions that occur in the interior of the fruit and, to a lesser extent, by the dilution of sodium hydroxide solution with water present in the pulp of the olives.En este artículo se describe por primera vez a nivel industrial el aumento de temperatura que se produce en el interior de los tanques de elaboración durante la etapa de cocido. A partir del estudio de las características térmicas de la etapa de cocido se han podido determinar relaciones entre las variables que definen el proceso. Se ha demostrado que la temperatura al inicio del tratamiento de cocido influye en otras de las características del proceso como la duración de éste o la pendiente del aumento lineal de temperatura durante la etapa. El estudio establece que esta generación de calor puede provenir principalmente de las reacciones de hidrólisis alcalina que ocurren en el interior del fruto y, en menor proporción, de la dilución de la solución de hidróxido de sodio con el agua presente en la pulpa de las aceitunas.

  17. Protótipo de um sistema de aquecimento de água para população de baixa renda usando energia solar e elétrica, com reaproveitamento de calor

    Directory of Open Access Journals (Sweden)

    Marco Antônio Silva Pereira

    2016-01-01

    Full Text Available Este artigo consiste em uma pesquisa sobre os vários meios de aquecimento de água para o banho, buscando o uso de alternativas para viabilizar o acesso da população de baixa renda a esses benefícios. A ideia principal é fazer uma combinação dos vários sistemas existentes a fim de produzir um protótipo eficiente e de baixo custo. O protótipo constitui-se de um sistema de aquecimento solar, recuperador de calor e de um misturador de água automatizado. A representação do sistema foi obtida por meio de uma maquete do protótipo ecológico de chuveiro, englobando as diversas tecnologias estudadas.Palavras-chave: Aquecedor solar. Recuperador de calor. Misturador automatizado. Microcontrolador.Prototype of a water heating system for low-income population using solar energy and power, with reuse of heatAbstractThis paper consists of a survey on the various means of heating water for the bath, trying to use of alternatives to allow access of the low-income population. The main idea is to make a blend of various existing systems in order to produce an efficient and cost effective prototype. The prototype consists of a system of solar heating, heat recovery and an automated water mixer. The representation of the system was obtained through a model of the ecological prototype shower encompassing the several studied technologies.Keywords: Solar heating. Heat recovery. Automated mixer. Microcontroller.

  18. Porøse materialer

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place

    2000-01-01

    Dette undervisningsnotat er en samling af noter, der refererer til den indledende del af kurset Materialmekanik og Porøse materailer på Insitut for Bærende Konstruktiner og Materialer (BKM).......Dette undervisningsnotat er en samling af noter, der refererer til den indledende del af kurset Materialmekanik og Porøse materailer på Insitut for Bærende Konstruktiner og Materialer (BKM)....

  19. Alterações fenotípicas em cultivares de alface selecionadas para calor Phenotypical alterations in lettuce genotypes selected for heat tolerance

    Directory of Open Access Journals (Sweden)

    José Henrique Conti

    2000-11-01

    Full Text Available Cultivares de alface selecionadas para o pendoamento lento e as mesmas que lhes deram origem foram analisadas quanto a variações morfológicas, com o objetivo de quantificar possíveis modificações adaptativas para as condições de cultivo em épocas de calor. Cultivares dos grupos "manteiga" (Regina, Glória, IAC 303, IAC 202, Sem Rival e Luciana "folha crespa" (Grand Rapids e Brisa e "americana" (Great Lakes e Mesa 659, foram avaliadas em dois plantios de verão, em Piracicaba, em delineamento de blocos casualizados. No primeiro experimento, (novembro/90, foram avaliadas as características de número de estômatos, espessura de folha e quantidade de clorofila total. No segundo, (setembro/91, foram avaliados o peso seco, peso fresco, porcentagem de matéria seca, tempo para pendoamento e número de folhas. As cultivares selecionadas para calor no grupo "manteiga" (Glória e Regina, apresentaram maior número de estômatos (respectivamente 9487/cm² e 7973/cm² e folhas mais grossas (respectivamente 556 mm e 439 mm e também, acumularam maior quantidade de matéria seca (respectivamente 24,55 g e 25,50 g. A cultivar selecionada para calor do grupo "folha crespa" (Brisa acumulou maior quantidade de matéria verde (446,77g e seca (22,40 g, da mesma forma que apresentou maior quantidade de estômatos (7.279/cm². Para as cultivares do grupo "americana", observou-se diferença significativa apenas para espessura de folha, sendo que a cultivar Mesa 659 apresentou folhas mais grossas (589 mm. Constataram-se aumentos significativos da biomassa vegetal nas cultivares selecionadas para calor em relação àquelas não selecionadas. As cultivares que atingiram maior produtividade de matéria seca por planta foram Mesa 659 (28,74 g, Great Lakes (27,17 g e Regina. Os resultados comprovaram que a seleção para o pendoamento lento indiretamente produziu variações adaptativas nas plantas de alface.Lettuce cultivars selected for slow bolting and

  20. Using eastern gamagrass to construct diets that limit intake and caloric density for dairy replacement heifers.

    Science.gov (United States)

    Coblentz, W K; Hoffman, P C; Esser, N M; Bertram, M G

    2012-10-01

    Previous research has shown that eastern gamagrass (EGG; Tripsacum dactyloides L.) will survive winter climatic conditions common throughout central Wisconsin, and will produce yields of dry matter (DM) ranging approximately from 7,000 to 10,000 kg/ha annually when managed with a 1-cut harvest system. The objective of this research was to determine whether the fibrous nature of this perennial warm-season grass could be effective in reducing the caloric density and DMI of corn silage/alfalfa haylage diets for replacement dairy heifers. A total of 120 Holstein dairy heifers were blocked by body weight (heavy, 424 ± 15.9 kg; medium, 369 ± 11.8 kg; light, 324 ± 22.4 kg), and then assigned to 15 individual pens containing 8heifers each. Eastern gamagrass forage was harvested, ensiled, and subsequently incorporated into blended corn silage/alfalfa haylage diets at rates of 0, 9.1, 18.3, or 27.4% of the total dietary DM (EGG0, EGG9, EGG18, and EGG27, respectively). These diets were offered during a 105-d evaluation period for ad libitum intake; however, the EGG0 diet also was offered on a limit-fed basis (LF), which was set at 85% of the voluntary intake of EGG0. Serial additions of EGG increased concentrations of neutral detergent fiber in blended diets from 39.6 (EGG0) to 48.7% (EGG27), and simultaneously reduced corresponding estimates of total digestible nutrients (TDN) from 68.2 to 61.3%, and net energy for gain from 1.07 to 0.83 Mcal/kg. Dry matter intakes for all diets offered ad libitum were greater than observed for LF (9.06 vs. 8.07 kg/d); however, DM intakes for diets containing EGG were reduced relative to EGG0 (9.40 vs. 8.94 kg/d). Similarly, intakes of TDN were greater for diets offered for ad libitum intake than for LF (5.84 vs. 5.50 kg/d); however, inclusion of EGG reduced TDN intakes relative to EGG0 (6.41 vs. 5.65 kg/d). This reduction was explained by both linear and quadratic effects of the inclusion rate of EGG in the diet. Over the 105-d trial

  1. Six and 12 Weeks of Caloric Restriction Increases β Cell Function and Lowers Fasting and Postprandial Glucose Concentrations in People with Type 2 Diabetes123

    Science.gov (United States)

    Sathananthan, Matheni; Shah, Meera; Edens, Kim L; Grothe, Karen B; Piccinini, Francesca; Farrugia, Luca P; Micheletto, Francesco; Man, Chiara Dalla; Cobelli, Claudio; Rizza, Robert A; Camilleri, Michael; Vella, Adrian

    2015-01-01

    Background: Caloric restriction alone has been shown to improve insulin action and fasting glucose metabolism; however, the mechanism by which this occurs remains uncertain. Objective: We sought to quantify the effect of caloric restriction on β cell function and glucose metabolism in people with type 2 diabetes. Methods: Nine subjects (2 men, 7 women) with type 2 diabetes [BMI (in kg/m2): 40.6 ± 1.4; age: 58 ± 3 y; glycated hemoglobin: 6.9% ± 0.2%] were studied using a triple-tracer mixed meal after withdrawal of oral diabetes therapy. The oral minimal model was used to measure β cell function. Caloric restriction limited subjects to a pureed diet (restriction. Results: Fasting glucose concentrations decreased significantly from baseline after 6 wk of caloric restriction with no further reduction after a further 6 wk of caloric restriction (9.8 ± 1.3, 5.9 ± 0.2, and 6.2 ± 0.3 mmol/L at baseline and after 6 and 12 wk of caloric restriction, respectively; P = 0.01) because of decreased fasting endogenous glucose production (EGP: 20.4 ± 1.1, 16.2 ± 0.8, and 17.4 ± 1.1 μmol · kg−1 · min−1 at baseline and after 6 and 12 wk of caloric restriction, respectively; P = 0.03). These changes were accompanied by an improvement in β cell function measured by the disposition index (189 ± 51, 436 ± 68, and 449 ± 67 10−14 dL · kg−1 · min−2 · pmol−1 at baseline and after 6 and 12 wk of caloric restriction, respectively; P = 0.01). Conclusions: Six weeks of caloric restriction lowers fasting glucose and EGP with accompanying improvements in β cell function in people with type 2 diabetes. An additional 6 wk of caloric restriction maintained the improvement in glucose metabolism. This trial was registered at clinicaltrials.gov as NCT01094054. PMID:26246321

  2. [Low caloric value and high salt content in the meals served in school canteens].

    Science.gov (United States)

    Paiva, Isabel; Pinto, Carlos; Queirós, Laurinda; Meister, Maria Cristina; Saraiva, Margarida; Bruno, Paula; Antunes, Delfina; Afonso, Manuel

    2011-01-01

    School lunch can contribute to aggravate food quality, by excess or deficiency, or it can contribute to compensate and alleviate them. This school meal should be an answer to combating the epidemic of obesity, and to feed some grace children. The objective was to study the nutritional composition of catering in canteens of public schools, from Northern municipalities in the District of Porto: Vila do Conde, Póvoa de Varzim, Santo Tirso and Trofa. Meals were subjected to laboratory analysis. Thirty two meals, four per each school were analysed, reference values for the analysis of the nutritional composition of meals were dietary reference intakes (USA) and eating well at school (UK). The average energy meal content was 447 kcal and the median 440 kcal (22% of daily calories). The average values of nutrients, per meal, were: lipids 9, 8 g, carbohydrate 65,7 g and proteins 24,0 g. In average the contribution for the meal energy was: 20% fat, 59% carbohydrate and 21% protein. In more than 75% of meals the contribution of lipid content was below the lower bound of the reference range. The average content of sodium chloride per meal was 3.4 g, and the confidence interval 95% to average 3.0 to 3.8 g, well above the recommended maximum value of 1.5 grams. The average content fiber per meal was 10.8 g higher than the minimum considered appropriate. In conclusion, the value low caloric meals was mainly due to the low fat content, and content salt of any of the components of the meal was very high.

  3. A randomized nutrition counseling intervention in pediatric leukemia patients receiving steroids results in reduced caloric intake.

    Science.gov (United States)

    Li, Rhea; Donnella, Hayley; Knouse, Phillip; Raber, Margaret; Crawford, Karla; Swartz, Maria C; Wu, Jimin; Liu, Diane; Chandra, Joya

    2017-02-01

    Quality of life in survivors of pediatric acute lymphocytic leukemia (ALL) can be compromised by chronic diseases including increased risk of second cancers, cardiovascular disease, and diabetes. Overweight or obesity further increases these risks. Steroids are a component of chemotherapy for ALL, and weight gain is a common side effect. To impact behaviors associated with weight gain, we conducted a randomized nutrition counseling intervention in ALL patients on treatment. ALL patients on a steroid-based treatment regimen at the MD Anderson Children's Cancer Hospital were recruited and randomized into control or intervention groups. The control group received standard care and nutrition education materials. The intervention group received monthly one-on-one nutrition counseling sessions, consisting of a baseline and 12 follow-up visits. Anthropometrics, dietary intake (3-day 24-hr dietary recalls) and oxidative stress measures were collected at baseline, 6 months, and postintervention. Dietary recall data were analyzed using the Nutrition Data System for Research. Twenty-two patients (median age 11.5 years), all in the maintenance phase of treatment, were recruited. The intervention group (n = 12) reported significantly lower calorie intake from baseline to 12-month follow-up and significant changes in glutamic acid and selenium intake (P < 0.05). Waist circumference was significantly associated with calorie, vitamin E, glutamic acid, and selenium intake. A year-long dietary intervention was effective at reducing caloric intake in pediatric ALL patients receiving steroid-based chemotherapy, indicating that this is a modality that can be built upon for obesity prevention and management. © 2016 Wiley Periodicals, Inc.

  4. Effect of exercise on the caloric intake of breast cancer patients undergoing treatment

    Directory of Open Access Journals (Sweden)

    C.L. Battaglini

    2008-08-01

    Full Text Available The purpose of this study was to examine the effects of an exercise intervention on the total caloric intake (TCI of breast cancer patients undergoing treatment. A secondary purpose was to determine whether or not a relationship existed between changes in TCI, body fat composition (%BF, and fatigue during the study, which lasted 6 months. Twenty females recently diagnosed with breast cancer, scheduled to undergo chemotherapy or radiation, were assigned randomly to an experimental (N = 10 or control group (N = 10. Outcome measures included TCI (3-day food diary, %BF (skinfolds, and fatigue (revised Piper Fatigue Scale. Each exercise session was conducted as follows: initial cardiovascular activity (6-12 min, followed by stretching (5-10 min, resistance training (15-30 min, and a cool-down (approximately 8 min. Significant changes in TCI were observed among groups (F1,18 = 8.582; P = 0.009, at treatments 2 and 3, and at the end of the study [experimental (1973 ± 419, control (1488 ± 418; experimental (1946 ± 437, control (1436 ± 429; experimental (2315 ± 455, control (1474 ± 294, respectively]. A significant negative correlation was found (Spearman rho(18 = -0.759; P < 0.001 between TCI and %BF and between TCI and fatigue levels (Spearman rho(18 = -0.541; P = 0.014 at the end of the study. In conclusion, the results of this study suggest that an exercise intervention administered to breast cancer patients undergoing medical treatment may assist in the mitigation of some treatment side effects, including decreased TCI, increased fatigue, and negative changes in body composition.

  5. No effect of caloric restriction on salivary cortisol levels in overweight men and women.

    Science.gov (United States)

    Tam, Charmaine S; Frost, Elizabeth A; Xie, Wenting; Rood, Jennifer; Ravussin, Eric; Redman, Leanne M

    2014-02-01

    The effect of weight loss by diet or diet and exercise on salivary cortisol levels, a measure of hypothalamic pituitary adrenal activity, in overweight individuals is not known. The objective was to test the hypothesis that 24 weeks of moderate caloric restriction (CR) (25%) by diet or diet and aerobic exercise would alter morning and diurnal salivary cortisol levels. Randomized control trial in an institutional research center. Thirty-five overweight (BMI: 27.8±0.7 kg/m(2)) but otherwise healthy participants (16 M/19 F). Participants were randomized to either calorie restriction (CR: 25% reduction in energy intake, n=12), calorie restriction+exercise (CR+EX: 12.5% reduction in energy intake+12.5% increase in exercise energy expenditure, n=12) or control (healthy weight-maintenance diet, n=11) for 6 months. Salivary cortisol measured at 8:00, 8:30, 11:00, 11:30, 12:30, 13:00, 16:00 and 16:30. Morning cortisol was defined as the mean cortisol concentration at 08:00 and 08:30. Diurnal cortisol was calculated as the mean of the 8 cortisol measures across the day. In the whole cohort, higher morning and diurnal cortisol levels were associated with impaired insulin sensitivity (morning: P=0.004, r(2)=0.24; diurnal: P=0.02, r(2)=0.15). Using mixed model analysis, there was no significant effect of group, time or sex on morning or diurnal cortisol levels. A 10% weight loss with a 25% CR diet alone or with exercise did not impact morning or diurnal salivary cortisol levels. © 2013.

  6. Balanced Caloric Restriction Minimizes Changes Caused by Aging on the Colonic Myenteric Plexus.

    Science.gov (United States)

    Mari, Renata de Britto; Stabille, Sandra Regina; de Faria, Haroldo Garcia; Pereira, Joice Naiara Bertaglia; Guimarães, Juliana Plácido; Marinsek, Gabriela Pustiglione; de Souza, Romeu Rodrigues

    2018-05-04

    Aging can promote significant morphofunctional changes in the gastrointestinal tract (GIT). Regulation of GIT motility is mainly controlled by the myenteric neurons of the enteric nervous system. Actions that aim at decreasing the aging effects in the GIT include those related to diet, with caloric restriction (CR). The CR is achieved by controlling the amount of food or by manipulating the components of the diet. Therefore, the objective of this study was to evaluate different levels of CR on the plasticity of nicotinamide adenine dinucleotide phosphate- (NADPH-) reactive myenteric neurons in the colon of Wistar rats during the aging process using ultrastructural (transmission electron microscopy) and morphoquantitative analysis. Wistar male rats (Rattus norvegicus) were distributed into 4 groups (n = 10/group): C, 6-month-old animals; SR, 18-month-old animals fed a normal diet; CRI, 18-month-old animals fed a 12% CR diet; CRII, 18-month-old animals fed a 31% CR diet. At 6 months of age, animals were transferred to the laboratory animal facility, where they remained until 18 months of age. Animals of the CRI and CRII groups were submitted to CR for 6 months. In the ultrastructural analysis, a disorganization of the periganglionar matrix with the aging was observed, and this characteristic was not observed in the animals that received hypocaloric diet. It was observed that the restriction of 12.5% and 31% of calories in the diet minimized the increase in density and cell profile of the reactive NADPH neurons, increased with age. This type of diet may be adapted against gastrointestinal disturbances that commonly affect aging individuals.

  7. Habitual sleep variability, not sleep duration, is associated with caloric intake in adolescents.

    Science.gov (United States)

    He, Fan; Bixler, Edward O; Berg, Arthur; Imamura Kawasawa, Yuka; Vgontzas, Alexandros N; Fernandez-Mendoza, Julio; Yanosky, Jeff; Liao, Duanping

    2015-07-01

    The objective of this study was to investigate the associations between objectively measured habitual sleep duration (HSD), habitual sleep variability (HSV), and energy and snack intake in adolescents. We used data from 324 adolescents who participated in the Penn State Child Cohort follow-up examination. Actigraphy was used over seven consecutive nights to estimate nightly sleep duration. The seven-night mean and standard deviation of sleep duration were used to represent HSD and HSV, respectively. The Youth/Adolescent Food Frequency Questionnaire was used to obtain the daily average total energy, protein, fat, and carbohydrate intake, and number of snacks consumed. Linear regression models were used to investigate the associations between habitual sleep patterns and caloric, protein, fat, and carbohydrate intake. Proportional odds models were used to associate habitual sleep patterns with snack consumption. After adjusting for age, sex, race, body mass index (BMI) percentile, and smoking status, an increased HSV was associated with a higher energy intake, particularly from fat and carbohydrate. For example, with a 1-h increase in HSV, there was a 170 (66)-kcal increase in the daily total energy intake. An increased HSV was also related to increased snack consumption, especially snacks consumed after dinner. For instance, a 1-h increase in HSV was associated with 65% and 94% higher odds of consuming more snacks after dinner during school/workdays and weekends/vacation days, respectively. Neither energy intake nor snack consumption was significantly related to HSD. High habitual sleep variability, not habitual sleep duration, is related to increased energy and food consumption in adolescents. Maintaining a regular sleep pattern may decrease the risk of obesity in adolescents. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Thermal treatment of high-caloric waste in fluidized bed incineration plants in Austria

    International Nuclear Information System (INIS)

    Ragossnig, A.M.

    2001-05-01

    The importance of thermal treatment of waste and residues in Austria is expected to rise due to the current changes of the legal situation in waste management. Assessing the rank order of different thermal treatment processes for waste management it has been shown that - especially caused by the rising importance of the mechanical treatment step in the mechanical-biological residual waste treatment and the subsequent necessity of the thermal treatment of a high-caloric preprocessed waste stream - the importance of the fluidized bed technology will increase. The main advantages are the high existing capacities as well as the flexibility of this technology in regard of fuel properties and further on the fact of the lacking influence of the ash towards the quality of a product. This is true although the thermal treatment in fluidized bed incinerators requires some processing of the waste. This doctoral thesis also contains a thorough physical and chemical characterization of various waste fuels - especially those which have been used during full scale incineration experiments. This characterization includes a comparison with fossil fuel. The practical part contains the documentation and balancing of full scale incineration experiments. A comparison of a reference experiment with experiments when waste fuel has been thermally utilized showed that a significant increase of emissions to the atmosphere has not been observed. Based on the incineration experiments conclusions in regard of waste fuels as well as different categories of thermal treatment plants are being stated. Finally, a recommendation of the assignation of various waste streams to different categories of thermal treatment plants is being made. (author)

  9. Magneto-caloric effect in the pseudo-binary intermetallic YPrFe{sub 17} compound

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Pablo [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Gorria, Pedro, E-mail: pgorria@uniovi.es [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Sanchez Llamazares, Jose L. [Division de Materiales Avanzados, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San Jose 2055, CP 78216, San Luis Potosi (Mexico); Perez, Maria J. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain); Franco, Victorino [Departamento de Fisica de la Materia Condensada, ICMSE-CSIC, Universidad de Sevilla, P.O. Box 1065, 41080 Sevilla (Spain); Reiffers, Marian; Kovac, Jozef [Institute of Experimental Physics, Watsonova 47, SK-04001 Kosice (Slovakia); Puente-Orench, Ines [Institute Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble (France); Blanco, Jesus A. [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo, s/n, 33007 Oviedo (Spain)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer YPrFe{sub 17} exhibits a broad {Delta}S{sub M}(T) associated with the ferro-to-paramagnetic phase transition (T{sub C} Almost-Equal-To 290 K). Black-Right-Pointing-Pointer We obtain |{Delta}S{sub M}| Almost-Equal-To 2.3 J kg{sup -1} K{sup -1} and RCP Almost-Equal-To 100 J kg{sup -1}for a magnetic field change of 1.5 T. Black-Right-Pointing-Pointer A single master curve for {Delta}S{sub M} is found when compared with other isostructural R{sub 2}Fe{sub 17} binary alloys. - Abstract: We have synthesized the intermetallic YPrFe{sub 17} compound by arc-melting. X-ray and neutron powder diffraction show that the crystal structure is rhombohedral with R3{sup Macron }m space group (Th{sub 2}Zn{sub 17}-type). The investigated compound exhibits a broad isothermal magnetic entropy change {Delta}S{sub M}(T) associated with the ferro-to-paramagnetic phase transition (T{sub C} Almost-Equal-To 290 K). The |{Delta}S{sub M}| ( Almost-Equal-To 2.3 J kg{sup -1} K{sup -1}) and the relative cooling power ( Almost-Equal-To 100 J kg{sup -1}) have been calculated for applied magnetic field changes up to 1.5 T. A single master curve for {Delta}S{sub M} under different values of the magnetic field change can be obtained by a rescaling of the temperature axis. The results are compared and discussed in terms of the magneto-caloric effect in the isostructural R{sub 2}Fe{sub 17} (R = Y, Pr and Nd) binary intermetallic alloys.

  10. Calibration of a Fusion Experiment to Investigate the Nuclear Caloric Curve

    Science.gov (United States)

    Keeler, Ashleigh

    2017-09-01

    In order to investigate the nuclear equation of state (EoS), the relation between two thermodynamic quantities can be examined. The correlation between the temperature and excitation energy of a nucleus, also known as the caloric curve, has been previously observed in peripheral heavy-ion collisions to exhibit a dependence on the neutron-proton asymmetry. To further investigate this result, fusion reactions (78Kr + 12C and 86Kr + 12C) were measured; the beam energy was varied in the range 15-35 MeV/u in order to vary the excitation energy. The light charged particles (LCPs) evaporated from the compound nucleus were measured in the Si-CsI(TI)/PD detector array FAUST (Forward Array Using Silicon Technology). The LCPs carry information about the temperature. The calibration of FAUST will be described in this presentation. The silicon detectors have resistive surfaces in perpendicular directions to allow position measurement of the LCP's to better than 200 um. The resistive nature requires a position-dependent correction to the energy calibration to take full advantage of the energy resolution. The momentum is calculated from the energy of these particles, and their position on the detectors. A parameterized formula based on the Bethe-Bloch equation was used to straighten the particle identification (PID) lines measured with the dE-E technique. The energy calibration of the CsI detectors is based on the silicon detector energy calibration and the PID. A precision slotted mask enables the relative positions of the detectors to be determined. DOE Grant: DE-FG02-93ER40773 and REU Grant: PHY - 1659847.

  11. Ethanol reformation combined with CO{sub 2} absorption for the production of hydrogen; Reformacion de etanol combinada con absorcion de CO{sub 2} para produccion de hidrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Beltran-Pina, B.B.; Delgado-Vigil, M.D.; Salinas-Gutierrez, J.M.; Lopez-Ortiz, A.; Collins-Martinez, V. [Centro de Investigacion en Materiales Avanzados S. C, Chihuahua, Chihuahua (Mexico)]. E-mail: bogdan.beltran@cimav.edu.mx

    2009-09-15

    caracterizados por difraccion de rayos X (XRD), microscopia electronica de barrido (SEM), y area superficial (isoterma BET). Se obtuvo un catalizador con fase activa bien dispersa y con area superficial de 170 m{sup 2}/gr. La evaluacion de la reaccion de reformacion de etanol con vapor se realizo considerando un sistema transiente y en un reactor de lecho fijo de acero inoxidable donde se introdujeron las mezclas del catalizador y de los absorbentes de CO{sub 2}; la reaccion se llevo a cabo a una temperatura de 600 grados centigrados, con una relacion de alimentacion de agua/alcohol de 6:1. La cuantificacion de los gases producidos durante la reaccion (H{sub 2}, CO{sub 2}, CO y CH{sub 4}) se efectuo mediante cromatografia de gases. Se observo un aumento en la selectividad a hidrogeno al agregar el absorbente en la cama catalitica de 85% a 98% con dolomita y a 97% con zirconato de sodio. Asi mismo se obtuvo una disminucion considerable en la selectividad hacia los subproductos tales como: CH{sub 4} y CO{sub 2}. Se determino la cantidad de carbon depositado sobre la superficie de los materiales. Este incremento en la produccion de hidrogeno es atribuido al desplazamiento del equilibrio termodinamico de la reaccion de reformacion de acuerdo con el principio de Le Chatelier.

  12. Sinterização de filmes finos de LiNbO3 em forno microondas: estudo da influência da direção do fluxo de calor Sintering of LiNbO3 thin films in microwave furnace: study of the influence of the heat flow direction

    Directory of Open Access Journals (Sweden)

    N. S. L. S. Vasconcelos

    2004-06-01

    Full Text Available Filmes finos de LiNbO3 foram preparados pelo método dos precursores poliméricos e depositados por "spin coating" sobre substratos de safira (0001. Os filmes foram tratados em forno microondas doméstico a 400 ºC por 15 e 20 min. Um material com alta perda dielétrica (susceptor de SiC foi usado para absorver energia das microondas e transformá-la em calor. Este calor foi transferido para o filme a fim de promover a sua cristalização. O susceptor foi posicionado acima do filme ou embaixo do substrato. Desta forma, a influência da direção do fluxo de calor na cristalização das amostras foi verificada. Os filmes foram caracterizados por difração de raios X, microscopia de força atômica e espectrofotometria (transmitância na região UV-visível e o índice de refração foi determinado por elipsometria. O crescimento epitaxial foi observado para o filme com susceptor posicionado embaixo do substrato. Verificou-se que os grãos apresentaram crescimento aleatório quando o susceptor foi posicionado acima do filme. Os filmes apresentaram-se relativamente densos, homogêneos e lisos, com boas propriedades ópticas.LiNbO3 thin films were prepared using a polymeric precursor solution deposited by spin coating on (0001 sapphire substrate. Heat treatment of the films was carried out in a microwave oven at 400 ºC for 15 and 20 min. A SiC susceptor (material with high dielectric loss was used to absorb microwave energy and transfer the heat to the film in order to promote crystallization. The susceptor was placed above the film or below the substrate. Thus, the influence of the heat flux direction on the sample crystallization was verified. The films were characterized by X-ray diffraction, atomic force microscopy and spectrophotometry (transmittance in the UV-Visible region and the refractive index was determined with an ellipsometer. The epitaxial growth was observed for the film with the susceptor placed below the substrate. Random growth

  13. MODELADO DE LAS ISOTERMAS DE SORCIÓN Y DEL CALOR ISOSTÉRICO DE SORCIÓN EN PULPA DE MANGO cv. TOMMY ATKINS MODELAGEM DE ISOTERMAS DE SORÇÃO E CALOR ISOSTÉRICO DE SORÇÃO DE POLPA DE MANGA cv. TOMMY ATKINS MODELING SORPTION ISOTHERMS AND ISOSTERIC HEAT OF SORPTION OF MANGO PULP cv. TOMMY ATKINS

    Directory of Open Access Journals (Sweden)

    JOSÉ BON

    2012-12-01

    Full Text Available El mango es un producto agrícola de gran importancia para diferentes países en vías de desarrollo, el cual ha incrementado su demanda por sus propiedades nutricionales y características exóticas. La relación entre el contenido de humedad y la actividad de agua suministra información útil para el procesamiento del mango, especialmente en las operaciones de secado y almacenamiento. La actividad de agua y el contenido de humedad de la pulpa de mango (Mangifera indica L. cv. Tommy Atkins fue analizada para determinar las isotermas de sorción. La actividad de agua fue medida utilizando un higrómetro eléctrico a cinco diferentes temperaturas (10, 20, 30, 40 y 50 °C y amplios rangos de contenido de humedad (2.829-0.031 kg kg-1 b.s. y actividad de agua (0.977-0.215. Un modelo teórico (GAB y cuatro ecuaciones empíricas (Oswin, Henderson, Halsey y Ratti fueron utilizados para representar las isotermas de sorción. Después de considerar diferentes criterios, el modelo de GAB fue evaluado como la mejor opción para representar el equilibrio higroscópico de la pulpa de mango (RMSE = 0.057, VAR = 0.996. Las isotermas mostraron un comportamiento acorde a los materiales agroalimentarios y similar al reportado para pulpa de mango de otras variedades. El calor isostérico de sorción fue calculado utilizando la ecuación de Clausius-Clapeyron a partir del modelo de GAB. Se observó una disminución en el calor isostérico de sorción al aumentar el contenido de humedad de equilibrio, con gran efecto de la humedad a valores por debajo de 0.8 kg kg-1 (b.s..A manga é um produto agrícola em países de desenvolvimento econômico, com grande aceitação devido a suas propriedades nutricionais e características exóticas. A relação entre o conteúdo de umidade e atividade de água proporciona informação útil para o processamento do mango, especialmente nas operações de secagem e armazenamento. A atividade de água e o conteúdo de umidade da

  14. 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

  15. Las cosas por su nombre

    OpenAIRE

    Storani, Emilia

    2017-01-01

    El artículo propone indagar sobre los modos y diferentes formatos que se utilizan tanto en la escritura como en la lectura, para articular con las luchas por la identidad de género. La Ley de Identidad de Género ha sido un puntapié clave para pensarnos a nosotros mismos culturalmente y para pensar a los demás. Pero, ¿cómo mencionamos, escribimos y leemos las diferentes identidades? La escritura, también es un mundo transformador para quienes bregan por una sociedad más libre y sin prejuicios....

  16. Ptose palpebral causada por Paquidermoperiostose

    Directory of Open Access Journals (Sweden)

    Patricia Regina de Pinho Tavares

    2014-08-01

    Full Text Available A paquidermoperiostose é uma síndrome caracterizada por acometimento cutâneo e ósseo, e em alguns casos ocorre comprometimento palpebral leve. É uma síndrome rara, idiopática ou hereditária, com provável herança autossômica dominante de penetrância variável. Descreve-se o caso de um paciente com ptose grave por paquidermoperiostose elucidando sua fisiopatologia e conduta cirúrgica aplicada.

  17. Diverticulitis yeyunal perforada por enterolito.

    OpenAIRE

    Marenco De la Cuadra, Beatriz; Gomez-Rosado, Juan-Carlos; Capitan-Morales, Luis-Cristobal; Valdés Hernández, Javier; Reyes-lopera, N.J. De los

    2012-01-01

    La diverticulosis yeyunal es una enfermedad adquirida rara. Casi el 60-70% keeps asymptomátic or Con síntomas crónicos inespecíficos, aunque puede presentarse como un abdomen agudo. La perforación debida a enterolitos es una causa extremadamente rara do complicación, y puede producirse por la impactación de ésta contra la pared intestinal. Presentamos caso de un varón de 82 años que acude a urgencias por un dolor súbito abdominal, difuso, con irritación peritoneal, leucocitosis con neutro...

  18. Mortalidad intrahospitalaria por accidente cerebrovascular

    OpenAIRE

    Federico Rodríguez Lucci; Virginia Pujol Lereis; Sebastián Ameriso; Guillermo Povedano; María F. Díaz; Alejandro Hlavnicka; Néstor A. Wainsztein; Sebastián F. Ameriso

    2013-01-01

    La mortalidad global por accidente cerebrovascular (ACV) ha disminuido en las últimas tres décadas, probablemente debido a un mejor control de los factores de riesgo vascular. La mortalidad hospitalaria por ACV ha sido tradicionalmente estimada entre 6 y 14% en la mayoría de las series comunicadas. Sin embargo, los datos de ensayos clínicos recientes sugieren que esta cifra sería sustancialmente menor. Se revisaron datos de pacientes internados con diagnóstico de ACV del Banco de Datos de Str...

  19. Soluble Fermentable Dietary Fibre (Pectin) Decreases Caloric Intake, Adiposity and Lipidaemia in High-Fat Diet-Induced Obese Rats

    Science.gov (United States)

    Adam, Clare L.; Thomson, Lynn M.; Williams, Patricia A.; Ross, Alexander W.

    2015-01-01

    Consumption of a high fat diet promotes obesity and poor metabolic health, both of which may be improved by decreasing caloric intake. Satiety-inducing ingredients such as dietary fibre may be beneficial and this study investigates in diet-induced obese (DIO) rats the effects of high or low fat diet with or without soluble fermentable fibre (pectin). In two independently replicated experiments, young adult male DIO rats that had been reared on high fat diet (HF; 45% energy from fat) were given HF, low fat diet (LF; 10% energy from fat), HF with 10% w/w pectin (HF+P), or LF with 10% w/w pectin (LF+P) ad libitum for 4 weeks (n = 8/group/experiment). Food intake, body weight, body composition (by magnetic resonance imaging), plasma hormones, and plasma and liver lipid concentrations were measured. Caloric intake and body weight gain were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Body fat mass increased in HF, was maintained in LF, but decreased significantly in LF+P and HF+P groups. Final plasma leptin, insulin, total cholesterol and triglycerides were lower, and plasma satiety hormone PYY concentrations were higher, in LF+P and HF+P than in LF and HF groups, respectively. Total fat and triglyceride concentrations in liver were greatest in HF, lower in LF and HF+P, and lowest in the LF+P group. Therefore, the inclusion of soluble fibre in a high fat (or low fat) diet promoted increased satiety and decreased caloric intake, weight gain, adiposity, lipidaemia, leptinaemia and insulinaemia. These data support the potential of fermentable dietary fibre for weight loss and improving metabolic health in obesity. PMID:26447990

  20. Moderate caloric restriction during gestation in rats alters adipose tissue sympathetic innervation and later adiposity in offspring.

    Directory of Open Access Journals (Sweden)

    Ana Paula García

    Full Text Available Maternal prenatal undernutrition predisposes offspring to higher adiposity in adulthood. Mechanisms involved in these programming effects, apart from those described in central nervous system development, have not been established. Here we aimed to evaluate whether moderate caloric restriction during early pregnancy in rats affects white adipose tissue (WAT sympathetic innervation in the offspring, and its relationship with adiposity development. For this purpose, inguinal and retroperitoneal WAT (iWAT and rpWAT, respectively were analyzed in male and female offspring of control and 20% caloric-restricted (from 1-12 d of pregnancy (CR dams. Body weight (BW, the weight, DNA-content, morphological features and the immunoreactive tyrosine hydroxylase and Neuropeptide Y area (TH+ and NPY+ respectively, performed by immunohistochemistry of both fat depots, were studied at 25 d and 6 m of age, the latter after 2 m exposure to high fat diet. At 6 m of life, CR males but not females, exhibited greater BW, and greater weight and total DNA-content in iWAT, without changes in adipocytes size, suggesting the development of hyperplasia in this depot. However, in rpWAT, CR males but not females, showed larger adipocyte diameter, with no changes in DNA-content, suggesting the development of hypertrophy. These parameters were not different between control and CR animals at the age of 25 d. In iWAT, both at 25 d and 6 m, CR males but not females, showed lower TH(+ and NPY(+, suggesting lower sympathetic innervation in CR males compared to control males. In rpWAT, at 6 m but not at 25 d, CR males but not females, showed lower TH(+ and NPY(+. Thus, the effects of caloric restriction during gestation on later adiposity and on the differences in the adult phenotype between internal and subcutaneous fat depots in the male offspring may be associated in part with specific alterations in sympathetic innervation, which may impact on WAT architecture.

  1. ISOTERMAS E CALOR ISOSTÉRICO DE ADSORÇÃO DA ÁGUA DO AMIDO DE QUINOA

    Directory of Open Access Journals (Sweden)

    AUGUSTO PUMACAHUA RAMOS

    2017-07-01

    Full Text Available A quinoa possui mais de 60% de amido, sendo uma alternativa de extração e comercialização. Para isto é necessário conhecer o comportamento do amido frente à temperatura e umidade relativa do ar. O objetivo desta pesquisa foi avaliar as isotermas de adsorção do amido de quinoa em cinco temperaturas (20, 30, 40, 50 e 60ºC e dez atividades de água (0,036 a 0,907. Os pontos experimentais foram ajustados aos modelos matemáticos GAB, Oswin, Henderson, Peleg e Ferro-Foltan. Foram determinadas as energias de ativação da adsorção da água pelas constantes do modelo GAB e o calor isostérico pelo modelo de Peleg. As isotermas mostraram ser do tipo II na classificação de Brunauer. Os teores de água da monocamada (Xm determinados pelo modelo de GAB variaram de 7,90% a 10,38% base seca (b.s. para temperaturas de 60 e 20°C e as energias de ativação obtidas pelas constantes Xm, C e K do modelo de GAB foram de 300; 160 e 6 kJ/kg, respectivamente. O calor isostérico de adsorção foi de 3732 kJ/kg para umidade de equilíbrio de 0,5% b.s. e diminuiu com o aumento da umidade até valor próximo ao calor latente de vaporização da água pura a 36% b.s. As propriedades determinadas são características de amidos com elevado teor de amilopectina.

  2. La Violación de la Segunda Ley de la Termodinámica por el Método de Elementos Finitos

    OpenAIRE

    Limache, Alejandro Cesar; Rojas Fredini, Pablo Sebastián; Murillo, Marina H.

    2016-01-01

    El presente artículo pretende alertar sobre un hecho grave: la Segunda Ley de la Termodinámica es violada como consecuencia de la discretización numérica resultante de la aplicación del Método de Elementos Finitos (FEM, por Finite Element Method). En este trabajo se estudia la consistencia termodinámica de las formulaciones FEM. El estudio está basado en el análisis de la ecuación del calor 1-Dimensional (1D) y 2-Dimensional (2D). Los resultados presentados afectan a todas las simulaciones de...

  3. Comportamiento a la Corrosión del Acero API X70 Soldado por el Proceso de Doble Arco Sumergido Inmerso en Diferentes Medios Corrosivos

    OpenAIRE

    Montes, Omar Francisco; Garcés, Rocío Saldaña; Reyes, Felipe A. Reyes; Robledo, Patricia del Carmen Zambrano; López, Francisco H. Estupiñán; Calderón, Facundo Almeraya

    2016-01-01

    Resumen Los aceros API X70 son aplicados en fabricación y construcción de tuberías para el transporte de hidrocarburos, sin embargo, a un lapso de tiempo se degradan debido al medio ambiente al cual están expuestos; influyendo en la velocidad y tipo de corrosión sobre las superficies del metal base (MB), zona afectada por el calor (ZAC) y zona de fusión (ZF). A fin de conocer y evaluar la susceptibilidad a la corrosión en uniones del acero API X70 sometido a diferentes medios corrosivos, vari...

  4. Análisis simplificado de las etapas de control y potencia de un sistema de calentamiento por inducción electromagnética

    OpenAIRE

    Villalba, Guillermo Alejandro; Bonfiglioli, Ernesto; Moya, Javier Alberto; Rodriguez, Martín Miguel

    2012-01-01

    p. 81-96 Un sistema de calentamiento por inducción electromagnética (también conocido como horno de inducción) es uno de los más modernos dispositivos eléctricos. Un horno de inducción al entrar en funcionamiento es capaz de generar gran cantidad de calor concentrado únicamente sobre el material (metal) a fundir, en muy poco tiempo, con lo cual se destaca su gran eficiencia; con la ventaja de no generar gases contaminantes que puedan afectar al ambiente, ni al metal a calentar. Siendo muy ...

  5. 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...

  6. Effects of immobilisation and caloric restriction on antioxidant parameters and T-cell apoptosis in healthy young men

    Science.gov (United States)

    Ellinger, S.; Arendt, B. M.; Boese, A.; Juschus, M.; Schaefer, S.; Stoffel-Wagner, B.; Goerlich, R.

    Background: Astronauts are exposed to oxidative stress due to radiation and microgravity, which might impair immune functions. Effects of hypocaloric nutrition as often observed in astronauts on oxidative stress and immune functions are not clear. We investigated, if microgravity, simulated by 6 Head-down tilt (HDT) and caloric restriction (-25%, fat reduced) with adequate supply of micronutrients affect DNA-damage in peripheral leukocytes, antioxidant parameters in plasma, and T-cell apoptosis. Material & Methods: 10 healthy male non-smokers were subjected to 4 different interventions (normocaloric diet or caloric restriction (CR) in upright position (UP) or HDT) for 14 days each (cross-over). DNA-damage in peripheral leukocytes (Comet Assay), trolox equivalent antioxidant capacity (TEAC) and uric acid in plasma were measured before, after 5, 10, and 13 days of intervention, and after 2 days recovery. T-cell apoptosis (Annexin V binding test) was assessed before and after intervention. Results: Preliminary results show that only endogenous, but not ex vivo H2O2-induced DNA strand breaks were reduced by CR compared to normocaloric diet. In upright position, endogenous DNA strand breaks decreased continuously during CR, reaching significance after recovery. During HDT, caloric restriction seems to counteract a temporary increase in DNA strand breaks observed in subjects receiving normocaloric diet. TEAC was reduced during HDT compared to UP in subjects under caloric restriction. An increase in plasma uric acid related to intervention occurred only after 5 days HDT in CR vs. normocaloric diet. T-cell apoptosis was not affected by any kind of intervention. Conclusion: Neither HDT nor CR with sufficient supply of micronutrients seem to induce oxidative stress or T-cell apoptosis in healthy young men. In contrast, CR might prevent endogenous DNA-damage in peripheral leukocytes. As DNA-damage is a risk factor for carcinogenesis, protective effects of energy reduction are

  7. Effects of age and caloric restriction in the vascular response of renal arteries to endothelin-1 in rats.

    Science.gov (United States)

    Amor, Sara; García-Villalón, Angel Luis; Rubio, Carmen; Carrascosa, Jose Ma; Monge, Luis; Fernández, Nuria; Martín-Carro, Beatriz; Granado, Miriam

    2017-02-01

    Cardiovascular alterations are the most prevalent cause of impaired physiological function in aged individuals with kidney being one the most affected organs. Aging-induced alterations in renal circulation are associated with a decrease in endothelium-derived relaxing factors such as nitric oxide (NO) and with an increase in contracting factors such as endothelin-1(ET-1). As caloric restriction (CR) exerts beneficial effects preventing some of the aging-induced alterations in cardiovascular system, the aim of this study was to analyze the effects of age and caloric restriction in the vascular response of renal arteries to ET-1 in aged rats. Vascular function was studied in renal arteries from 3-month-old Wistar rats fed ad libitum (3m) and in renal arteries from 8-and 24-month-old Wistar rats fed ad libitum (8m and 24m), or subjected to 20% caloric restriction during their three last months of life (8m-CR and 24m-CR). The contractile response to ET-1 was increased in renal arteries from 8m and 24m compared to 3m rats. ET-1-induced contraction was mediated by ET-A receptors in all experimental groups and also by ET-B receptors in 24m rats. Caloric restriction attenuated the increased contraction to ET-1 in renal arteries from 8m but not from 24m rats possibly through NO release proceeding from ET-B endothelial receptors. In 24m rats, CR did not attenuate the aging-increased response of renal arteries to ET-1, but it prevented the aging-induced increase in iNOS mRNA levels and the aging-induced decrease in eNOS mRNA levels in arterial tissue. In conclusion, aging is associated with an increased response to ET-1 in renal arteries that is prevented by CR in 8m but not in 24m rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Actualidad y perspectivas de una bomba de calor de expansión directa con energía solar

    OpenAIRE

    Gorozabel-Chata, Francis-B.; Carbonell-Morales, Tania

    2016-01-01

    La bomba de calor de expansión directa con asistencia de energía solar se utiliza en el modo de calefacción para diversas aplicaciones entre las que podemos citar, calentamiento de agua, calentamiento de aire para climatizar edificios, desalinización de agua, secado solar entre otras. El presente trabajo revisa las principales investigaciones sobre esta tecnología enfocando sus aplicaciones para el calentamiento de agua, para lograr este objetivo se describen en detalle la configuración básic...

  9. Distúrbios causados pelo frio e pelo calor durante corridas de longa distância

    Directory of Open Access Journals (Sweden)

    1999-06-01

    Full Text Available Muitos corredores amadores e de elite participam todos os anos de corridas de longa distância. Quando estes eventos ocorrem em temperaturas altas ou baixas, aumenta o risco de distúrbios térmicos. Contudo, a hipertermia induzida pelo exercício, a hipotermia, a desidratação e outros problemas relacionados podem ser minimizados através de esclarecimentos e um preparo antes do evento. Este documento fornece recomendações para o diretor médico e outras autoridades da organização das corridas nas seguintes áreas: planejamento, profissionais envolvidos na organização, instalações, suprimentos, equipamento e comunicação; fornecimento de esclarecimentos aos participantes; avaliação do estresse térmico; fornecimento de líquidos; e prevenção de questões legais em potencial. Este posicionamento oficial também descreve as condições predisponentes, as formas de diagnóstico e o tratamento dos quatro distúrbios ambientais mais comuns: exaustão pelo calor, colapso pelo calor, hipotermia e congelamento de extremidades. Os objetivos deste documento são: 1 Educar os organizadores e os participantes de corridas de longa distância a respeito das formas mais comuns de distúrbios térmicos incluindo as condições predisponentes, sinais de alerta, suscetibilidade e a redução de sua incidência; 2 Alertar os organizadores sobre as suas responsabilidades civis em potencial no que concerne à segurança do evento e à prevenção de lesões; 3 Recomendar que os organizadores consultem arquivos locais de meteorologia e planejem eventos em horas que provavelmente causem menos estresse térmico de modo a minimizar os efeitos deletérios sobre os participantes; 4 Estimular os organizadores a alertar os participantes sobre o estresse térmico no dia da corrida e as suas implicações no que tange aos distúrbios causados pelo frio e pelo calor; 5 Informar os organizadores sobre as ações preventivas que podem reduzir a incidência dos

  10. A molecular mechanism for diacylglycerol-mediated promotion of negative caloric balance

    Directory of Open Access Journals (Sweden)

    Yanai H

    2009-12-01

    study demonstrated that 1-monoacylglycerol, a digestive product of DAG, increases serotonin release from the Caco-2 cells, and enhances expression of genes associated with β-oxidation, FA metabolism, and thermogenesis, and that serotonin increases expression of these genes, proposing a novel molecular mechanism for DAG-mediated promotion of negative caloric balance.Keywords: diacylglycerol, energy expenditure, intestine, serotonin, triacylglycerol

  11. Chemotherapy for isolated locoregional recurrence of breast cancer (CALOR): a randomised trial.

    Science.gov (United States)

    Aebi, Stefan; Gelber, Shari; Anderson, Stewart J; Láng, István; Robidoux, André; Martín, Miguel; Nortier, Johan W R; Paterson, Alexander H G; Rimawi, Mothaffar F; Cañada, José Manuel Baena; Thürlimann, Beat; Murray, Elizabeth; Mamounas, Eleftherios P; Geyer, Charles E; Price, Karen N; Coates, Alan S; Gelber, Richard D; Rastogi, Priya; Wolmark, Norman; Wapnir, Irene L

    2014-02-01

    Patients with isolated locoregional recurrences (ILRR) of breast cancer have a high risk of distant metastasis and death from breast cancer. We aimed to establish whether adjuvant chemotherapy improves the outcome of such patients. The CALOR trial was a pragmatic, open-label, randomised trial that accrued patients with histologically proven and completely excised ILRR after unilateral breast cancer who had undergone a mastectomy or lumpectomy with clear surgical margins. Eligible patients were enrolled from hospitals worldwide and were centrally randomised (1:1) to chemotherapy (type selected by the investigator; multidrug for at least four courses recommended) or no chemotherapy, using permuted blocks, and stratified by previous chemotherapy, oestrogen-receptor and progesterone-receptor status, and location of ILRR. Patients with oestrogen-receptor-positive ILRR received adjuvant endocrine therapy, radiation therapy was mandated for patients with microscopically involved surgical margins, and anti-HER2 therapy was optional. The primary endpoint was disease-free survival. All analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00074152. From Aug 22, 2003, to Jan 31, 2010, 85 patients were randomly assigned to receive chemotherapy and 77 were assigned to no chemotherapy. At a median follow-up of 4·9 years (IQR 3·6-6 ·0), 24 (28%) patients had disease-free survival events in the chemotherapy group compared with 34 (44%) in the no chemotherapy group. 5-year disease-free survival was 69% (95% CI 56-79) with chemotherapy versus 57% (44-67) without chemotherapy (hazard ratio 0·59 [95% CI 0·35-0·99]; p=0·046). Adjuvant chemotherapy was significantly more effective for women with oestrogen-receptor-negative ILRR (pinteraction=0·046), but analyses of disease-free survival according to the oestrogen-receptor status of the primary tumour were not statistically significant (pinteraction=0·43). Of the 81 patients who

  12. Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

    Directory of Open Access Journals (Sweden)

    Kabir Mohammad M

    2011-10-01

    Full Text Available Abstract Considerable interest has been shown in the ability of caloric restriction (CR to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake; on the other day, food is reduced or withheld altogether. Dietary restriction (DR - restriction of one or more components of intake (typically macronutrients with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1 Islamic Ramadan; 2 the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption; and 3 the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion.

  13. Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings.

    Science.gov (United States)

    Trepanowski, John F; Canale, Robert E; Marshall, Kate E; Kabir, Mohammad M; Bloomer, Richard J

    2011-10-07

    Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion.

  14. Chronic Caloric Restriction and Exercise Improve Metabolic Conditions of Dietary-Induced Obese Mice in Autophagy Correlated Manner without Involving AMPK

    Directory of Open Access Journals (Sweden)

    Mingxia Cui

    2013-01-01

    Full Text Available Aim. To investigate the role of AMPK activation and autophagy in mediating the beneficial effects of exercise and caloric restriction in obesity. Methods. Dietary-induced obesity mice were made and divided into 5 groups; one additional group of normal mice serves as control. Mice in each group received different combinations of interventions including low fat diet, caloric restriction, and exercise. Then their metabolic conditions were assessed by measuring serum glucose and insulin, serum lipids, and liver function. AMPK phosphorylation and autophagy activity were detected by western blotting. Results. Obese mice models were successfully induced by high fat diet. Caloric restriction consistently improved the metabolic conditions of the obese mice, and the effects are more prominent than the mice that received only exercise. Also, caloric restriction, exercise, and low fat diet showed a synergistic effect in the improvement of metabolic conditions. Western blotting results showed that this improvement was not related with the activation of AMPK in liver, skeletal muscle, or heart but correlates well with the autophagy activity. Conclusion. Caloric restriction has more prominent beneficial effects than exercise in dietary-induced obese mice. These effects are correlated with the autophagy activity and may be independent of AMPK activation.

  15. Impact of caloric and dietary restriction regimens on markers of health and longevity in humans and animals: a summary of available findings

    Science.gov (United States)

    2011-01-01

    Considerable interest has been shown in the ability of caloric restriction (CR) to improve multiple parameters of health and to extend lifespan. CR is the reduction of caloric intake - typically by 20 - 40% of ad libitum consumption - while maintaining adequate nutrient intake. Several alternatives to CR exist. CR combined with exercise (CE) consists of both decreased caloric intake and increased caloric expenditure. Alternate-day fasting (ADF) consists of two interchanging days; one day, subjects may consume food ad libitum (sometimes equaling twice the normal intake); on the other day, food is reduced or withheld altogether. Dietary restriction (DR) - restriction of one or more components of intake (typically macronutrients) with minimal to no reduction in total caloric intake - is another alternative to CR. Many religions incorporate one or more forms of food restriction. The following religious fasting periods are featured in this review: 1) Islamic Ramadan; 2) the three principal fasting periods of Greek Orthodox Christianity (Nativity, Lent, and the Assumption); and 3) the Biblical-based Daniel Fast. This review provides a summary of the current state of knowledge related to CR and DR. A specific section is provided that illustrates related work pertaining to religious forms of food restriction. Where available, studies involving both humans and animals are presented. The review includes suggestions for future research pertaining to the topics of discussion. PMID:21981968

  16. Durabilidade de fachadas: método de ensaio para verificação da resistência à ação de calor e choque térmico

    Directory of Open Access Journals (Sweden)

    Luciana Alves Oliveira

    Full Text Available A avaliação da durabilidade de sistemas construtivos envolve a identificação dos agentes agressivos do ambiente. Em países tropicais, tende a ser significativa a ação de agentes de degradação, como altas temperaturas, umidade, radiação ultravioleta e agentes biológicos. A ação desses agentes é mais atuante nas fachadas dos edifícios, por sofrerem continuamente aquecimento, em razão da radiação solar, e resfriamento, em função de chuvas ou oscilações térmicas, fenômeno conhecido como choque térmico. No Brasil, a resistência à ação de calor e choque térmico de fachadas é tratada na norma de desempenho - NBR 15575-4 (ABNT, 2013. Entretanto, o método de ensaio proposto por esta norma difere dos métodos de ensaios de normas estrangeiras, em alguns aspectos. Assim, o objetivo deste artigo é discutir e propor revisões no método de ensaio estabelecido na norma brasileira para avaliar a resistência dos elementos de fachada leve à ação de calor e choque térmico. A discussão e proposta de revisão do método de ensaio de choque térmico são baseadas em revisão bibliográfica, e pelos resultados de ensaios realizados conforme a NBR 15.575-4 (ABNT, 2013. Foram propostas as seguintes modificações: tempo de permanência do corpo de prova na fase aquecida, e dimensões e restrições impostas ao corpo-de-prova. Para a consideração de outros aspectos, como tempo e quantidades de ciclos, estudos ainda precisam ser desenvolvidos.

  17. DESAJUSTE EDUCATIVO POR REGIONES EN COLOMBIA: ¿COMPETENCIA POR SALARIOS O POR PUESTOS DE TRABAJO?

    Directory of Open Access Journals (Sweden)

    Maribel Castillo Caicedo

    2007-06-01

    Full Text Available Este trabajo aporta una perspectiva del fenómeno de la sobreeducación, entendida como un desajuste por exceso, entre el nivel educativo alcanzado por el individuo y el exigido por el puesto de trabajo en el cual se desempeña; esto se debe a que existe una demanda laboral estrecha de puestos de trabajo para personas calificadas en Colombia. Se analizan las contribuciones empíricas existentes y el debate sobre las mismas; se examinan las teorías que permiten explicar la existencia de un desajuste educativo y se realiza una revisión de la literatura internacional y nacional sobre el tema. Adicionalmente, se plantean una serie de hipótesis para desarrollar un esquema que permita determinar el comportamiento del individuo en el fenómeno de la sobreeducación.

  18. Consanguinidad por isonimia en Salta

    Directory of Open Access Journals (Sweden)

    Albeza, María V.

    2007-01-01

    Full Text Available Se estimó el coeficiente de parentesco por isonimia para localidades de la Puna, Valle Calchaquí y Valle de Lerma, a fin de evaluar diferentes factores evolutivos que podrían estar afectando la composición genética de la población. A partir de los apellidos de las parejas consignadas en fuentes primarias de información, se estimó la isonimia conyugal o marital, el coeficiente total Ft y sus componentes Fr (inbreeding azaroso y Fn (inbreeding no azaroso. De las localidades estudiadas, en la Puna se ha detectado sólo una pareja isónima en una de ellas, en el Valle Calchaquí, tres y ninguna en el Valle de Lerma. Tanto en el Valle Calchaquí como en el de Lerma, se han estimado valores negativos de Ft, y en la Puna se registran los valores más elevados. En las localidades estudiadas no se cumple el supuesto de transmisión patrilineal de apellidos por lo que los valores de Fr y por ende de Ft podrían estar subestimados. Es por ello que sería necesario contar con información desde otras vertientes metodológicas para corroborar, complementar y manejar cuidadosamente el análisis de los datos y las conclusiones que se obtienen.

  19. Alleviation of senescence and epithelial-mesenchymal transition in aging kidney by short-term caloric restriction and caloric restriction mimetics via modulation of AMPK/mTOR signaling.

    Science.gov (United States)

    Dong, Dan; Cai, Guang-Yan; Ning, Yi-Chun; Wang, Jing-Chao; Lv, Yang; Hong, Quan; Cui, Shao-Yuan; Fu, Bo; Guo, Ya-Nan; Chen, Xiang-Mei

    2017-03-07

    Renal fibrosis contributes to declining renal function in the elderly. What is unclear however, is whether epithelial-mesenchymal transition (EMT) contributes to this age-related renal fibrosis. Here, we analyzed indicators of EMT during kidney aging and investigated the protective effects and mechanisms of short-term regimens of caloric restriction (CR) or caloric restriction mimetics (CRMs), including resveratrol and metformin. High glucose was used to induce premature senescence and EMT in human primary proximal tubular cells (PTCs) in vitro. To test the role of AMPK-mTOR signaling, siRNA was used to deplete AMPK. Cellular senescence and AMPK-mTOR signaling markers associated with EMT were detected. CR or CRMs treatment alleviated age-related EMT in aging kidneys, which was accompanied by activation of AMPK-mTOR signaling. High glucose induced premature senescence and EMT in PTCs in vitro, which was accompanied by down-regulation of AMPK/mTOR signaling. CRMs alleviated high glucose-induced senescence and EMT via stimulation of AMPK/mTOR signaling. Activation of AMPK/mTOR signaling protected PTCs from high glucose-induced EMT and cellular senescence. Short-term regimens of CR and CRMs alleviated age-related EMT via AMPK-mTOR signaling, suggesting a potential approach to reducing renal fibrosis during aging.

  20. Celulitis por citomegalovirus Cytomegalovirus cellulitis

    Directory of Open Access Journals (Sweden)

    A. Ruiz Lascano

    2002-12-01

    Full Text Available Las lesiones cutáneas por citomegalovirus (CMV son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritematoedematosa. La tratamos con antibióticos sin mejoría, por lo que realizamos un estudio histopatológico de piel que mostró cambios citopáticos compatibles con infección por CMV. Los cultivos bacteriológicos y micológicos fueron negativos. La inmunohistoquímica específica para CMV y el estudio de reacción en cadena de la polimerasa (PCR de la biopsia de piel fueron positivas, al igual que la antigenemia. El tratamiento con ganciclovir produjo la mejoría del cuadro clínico. En la literatura revisada no hemos encontrado la celulitis como manifestación de enfermedad cutánea por CMV.Cutaneous lesions in CMV infection are rare, often a late manifestation of systemic infection, and usually herald a fatal course. A 70 year-old woman received a kidney transplantation one month before consulting and immunosuppressive therapy that included cyclosporine A and methylprednisone. She complained of fever, local pain in her right leg, and an erythematous and swelling plaque. She was treated with intravenous antibiotics without improvement. A skin biopsy was performed and the tissue obtained was sent for bacterial and fungal cultures as well as for histological examination. Cultures were negative. The biopsy showed CMV cytopathic changes. Immunoperoxidase staining was positive for CMV and polymerase chain reaction (PCR testing revealed CMV DNA. She was treated with ganciclovir with resolution of the lesion. CMV cellulitis is a rare cutaneous manifestation

  1. EXPRESIÓN SEMI-ANALÍTICA PARA EL CÁLCULO DE MATRICES DE CONDUCTIVIDAD DE ELEMENTOS FINITOS EN PROBLEMAS DE CONDUCCIÓN DE CALOR //\tA SEMI-ANALYTICAL EXPRESSION FOR CALCULATING FINITE ELEMENT CONDUCTIVITY MATRICES IN HEAT CONDUCTION PROBLEMS

    Directory of Open Access Journals (Sweden)

    Hector Godoy

    2012-12-01

    Full Text Available The heat transfer equation by conduction is not more than a mathematical expression of the energy conservation law for a given solid. Solving the equation which model this problem is generally very dificult or impossible in an analytical way, so it is necessary to make a discrete approximation of the continuous problem. In this paper, we present a methodology applied to the quadrilateral finite elements in problems of heat transfer by conduction, where the components of the thermal conductivity matrix are obtained by a semi-analytical expression and simple algebraic manipulations. This technique has been used successfully in stiness arrays' integrations of bidimensional and tridimensional finite elements, reporting substantial improvements of CPU times compared with the Gaussian integration. // RESUMEN: La ecuación para la transferencia de calor por conducción no es más que una expresión matemática de la ley de conservación de la energía para un sólido dado. La resolución de la ecuación que modela este problema generalmente es muy difícil o imposible de obtener de forma analítica, por ello es necesario efectuar una aproximación discreta del problema continuo. En este trabajo, se presenta una metodología aplicada a elementos finitos cuadriláteros en problemas de transferencia de calor por conducción, donde las componentes de la matriz de conductividad térmica son obtenidas mediante una expresión semi-analítica y manipulaciones algebraicas sencillas. Esta técnica ha sido utilizada exitosamente en integraciones de matrices de rigidez de elementos finitos bidimensionales y tridimensionales,reportando mejoras sustanciales de tiempos de CPU en comparación con la integración Gaussiana.

  2. High-Caloric and Chocolate Stimuli Processing in Healthy Humans: An Integration of Functional Imaging and Electrophysiological Findings

    Science.gov (United States)

    Asmaro, Deyar; Liotti, Mario

    2014-01-01

    There has been a great deal of interest in understanding how the human brain processes appetitive food cues, and knowing how such cues elicit craving responses is particularly relevant when current eating behavior trends within Westernized societies are considered. One substance that holds a special place with regard to food preference is chocolate, and studies that used functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) have identified neural regions and electrical signatures that are elicited by chocolate cue presentations. This review will examine fMRI and ERP findings from studies that used high-caloric food and chocolate cues as stimuli, with a focus on responses observed in samples of healthy participants, as opposed to those with eating-related pathology. The utility of using high-caloric and chocolate stimuli as a means of understanding the human reward system will also be highlighted, as these findings may be particularly important for understanding processes related to pathological overeating and addiction to illicit substances. Finally, research from our own lab that focused on chocolate stimulus processing in chocolate cravers and non-cravers will be discussed, as the approach used may help bridge fMRI and ERP findings so that a more complete understanding of appetitive stimulus processing in the temporal and spatial domains may be established. PMID:24434747

  3. High-Caloric and Chocolate Stimuli Processing in Healthy Humans: An Integration of Functional Imaging and Electrophysiological Findings

    Directory of Open Access Journals (Sweden)

    Deyar Asmaro

    2014-01-01

    Full Text Available There has been a great deal of interest in understanding how the human brain processes appetitive food cues, and knowing how such cues elicit craving responses is particularly relevant when current eating behavior trends within Westernized societies are considered. One substance that holds a special place with regard to food preference is chocolate, and studies that used functional magnetic resonance imaging (fMRI and event-related potentials (ERPs have identified neural regions and electrical signatures that are elicited by chocolate cue presentations. This review will examine fMRI and ERP findings from studies that used high-caloric food and chocolate cues as stimuli, with a focus on responses observed in samples of healthy participants, as opposed to those with eating-related pathology. The utility of using high-caloric and chocolate stimuli as a means of understanding the human reward system will also be highlighted, as these findings may be particularly important for understanding processes related to pathological overeating and addiction to illicit substances. Finally, research from our own lab that focused on chocolate stimulus processing in chocolate cravers and non-cravers will be discussed, as the approach used may help bridge fMRI and ERP findings so that a more complete understanding of appetitive stimulus processing in the temporal and spatial domains may be established.

  4. Effect of long-term caloric restriction on brain monoamines in aging male and female Fischer 344 rats.

    Science.gov (United States)

    Kolta, M G; Holson, R; Duffy, P; Hart, R W

    1989-05-01

    The present study examines the changes in central monoamines and their metabolites in aged male and female rats after long-term caloric restriction. Fischer 344 rats of both sexes (n = 5-10/group) were maintained on one of two dietary regimens: ad libitum NIH 31 diet or 60% by weight of the ad lib. intake (restricted), supplemented with vitamins and minerals. Animals received these diets from the age of 14 weeks until killed at 22.25 months of age. Caudate nucleus (CN), hypothalamus (HYPO), olfactory bulb (OB) and nucleus accumbens (NA) were assayed for content of norepinephrine (NE), dopamine (DA) and its metabolites (dihydroxyphenylacetic acid, DOPAC, and homovanillic acid, HVA) and serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) using HPLC/EC. Relative to the ad lib. group, restricted rats of both sex showed significant decreases in NE content in CN, HYPO and OB. DA and 5-HT content were decreased significantly in the CN and HYPO. No significant changes were found in the levels of DA metabolites in all brain regions studied. While the 5-HIAA level was significantly reduced in the HYPO and NA of the female restricted rats, it was increased several-fold in the OB of the male restricted animals. These preliminary results suggest that long-term caloric restriction alters brain monoamine concentrations, an effect which may in turn modify the normal rate of aging.

  5. Formation of S-(carboxymethyl)-cysteine in rat liver mitochondrial proteins: effects of caloric and methionine restriction.

    Science.gov (United States)

    Naudí, Alba; Jové, Mariona; Cacabelos, Daniel; Ayala, Victoria; Cabre, Rosanna; Caro, Pilar; Gomez, José; Portero-Otín, Manuel; Barja, Gustavo; Pamplona, Reinald

    2013-02-01

    Maillard reaction contributes to the chemical modification and cross-linking of proteins. This process plays a significant role in the aging process and determination of animal longevity. Oxidative conditions promote the Maillard reaction. Mitochondria are the primary site of oxidants due to the reactive molecular species production. Mitochondrial proteome cysteine residues are targets of oxidative attack due to their specific chemistry and localization. Their chemical, non-enzymatic modification leads to dysfunctional proteins, which entail cellular senescence and organismal aging. Previous studies have consistently shown that caloric and methionine restrictions, nutritional interventions that increase longevity, decrease the rate of mitochondrial oxidant production and the physiological steady-state levels of markers of oxidative damage to macromolecules. In this scenario, we have detected S-(carboxymethyl)-cysteine (CMC) as a new irreversible chemical modification in mitochondrial proteins. CMC content in mitochondrial proteins significantly correlated with that of the lysine-derived analog N (ε)-(carboxymethyl)-lysine. The concentration of CMC is, however, one order of magnitude lower compared with CML likely due in part to the lower content of cysteine with respect to lysine of the mitochondrial proteome. CMC concentrations decreases in liver mitochondrial proteins of rats subjected to 8.5 and 25 % caloric restriction, as well as in 40 and 80 % methionine restriction. This is associated with a concomitant and significant increase in the protein content of sulfhydryl groups. Data presented here evidence that CMC, a marker of Cys-AGE formation, could be candidate as a biomarker of mitochondrial damage during aging.

  6. 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.

  7. 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 .

  8. Energía calorífica necesaria, durante la soldadura en servicio de tuberías para el transporte de petróleo Necessary calorific energy, during the in-service welding of pipelines for petroleum transport

    Directory of Open Access Journals (Sweden)

    Félix Ramos Morales

    2009-03-01

    Full Text Available En el presente artículo, empleando el análisis por elementos finitos, se estudió el comportamiento térmico durante la soldadura de reparación, en condiciones de servicio, de un tubo que transporta petróleo. Se obtuvieron ecuaciones de regresión que relacionan a la temperatura máxima en la superficie interna del tubo y al tiempo de enfriamiento desde 800 ºC hasta 500 ºC de un punto situado en la zona afectada por el calor (ZAC, parámetros que gobiernan la ocurrencia de perforaciones en la pared del tubo y agrietamiento en frío respectivamente, con el calor de entrada de la soldadura, la temperatura de precalentamiento y el coeficiente de transferencia de calor por convección, variables que definen el comportamiento térmico durante la ejecución del proceso de soldadura. Se probó la existencia de una zona en que se satisfacen simultáneamente las ecuaciones obtenidas, para diferentes combinaciones de las variables relacionadas. Se presentaron nomogramas con un importante valor práctico, desarrollados a partir de la solución de las ecuaciones obtenidas.The thermal behavior during in service repair welding of oil transportation pipes was studied by finite element analysis in the present paper. Regression equations that relate peak temperature at the inner surface of the pipe and cooling time between 800 and 500ºC in the heat affected zone to the welding heat input, preheat temperature, and convection heat transfer coefficient were obtained. The former parameters govern, respectively, the possibility of burn through and cold cracking, and the latter parameters define the thermal behavior during welding. The existence of conditions that simultaneously satisfy the obtained equations, for different combinations of related variables, was proved. Graphical representations of relevant practical importance that were developed from the solution of obtained equations are presented.

  9. Effect of caloric restriction with or without n-3 polyunsaturated fatty acids on insulin sensitivity in obese subjects: A randomized placebo controlled trial.

    Science.gov (United States)

    Razny, Urszula; Kiec-Wilk, Beata; Polus, Anna; Goralska, Joanna; Malczewska-Malec, Malgorzata; Wnek, Dominika; Zdzienicka, Anna; Gruca, Anna; Childs, Caroline E; Kapusta, Maria; Slowinska-Solnica, Krystyna; Calder, Philip C; Dembinska-Kiec, Aldona

    2015-12-01

    Caloric restriction and n-3 polyunsaturated fatty acid (PUFA) supplementation protect from some of the metabolic complications. The aim of this study was to assess the influence of a low calorie diet with or without n-3 PUFA supplementation on glucose dependent insulinotropic polypeptide (GIP) output and insulin sensitivity markers in obese subjects. Obese, non-diabetic subjects (BMI 30-40 kg/m(2)) and aged 25-65 yr. were put on low calorie diet (1200-1500 kcal/day) supplemented with either 1.8 g/day n-3 PUFA (DHA/EPA, 5:1) (n = 24) or placebo capsules (n = 24) for three months in a randomized placebo controlled trial. Insulin resistance markers and GIP levels were analysed from samples obtained at fasting and during an oral glucose tolerance test (OGTT). Caloric restriction with n-3 PUFA led to a decrease of insulin resistance index (HOMA-IR) and a significant reduction of insulin output as well as decreased GIP secretion during the OGTT. These effects were not seen with caloric restriction alone. Changes in GIP output were inversely associated with changes in red blood cell EPA content whereas fasting GIP level positively correlated with HOMA-IR index. Blood triglyceride level was lowered by caloric restriction with a greater effect when n-3 PUFA were included and correlated positively with fasting GIP level. Three months of caloric restriction with DHA + EPA supplementation exerts beneficial effects on insulin resistance, GIP and triglycerides. Combining caloric restriction and n-3 PUFA improves insulin sensitivity, which may be related to a decrease of GIP levels.

  10. The type of caloric sweetener added to water influences weight gain, fat mass, and reproduction in growing Sprague-Dawley female rats.

    Science.gov (United States)

    Light, Heather R; Tsanzi, Embedzayi; Gigliotti, Joseph; Morgan, Keri; Tou, Janet C

    2009-06-01

    Caloric sweetened beverages have been suggested to be a major dietary contributor to weight gain, particularly among adolescents. Dietary recommendations are for moderating intakes of added sugars; however, the question remains whether certain types of sugars should be limited. The objective of this study was to determine the effect of drinking different caloric sweetened beverages on the development of adiposity, metabolic, and endocrine disorders. Young (age 28 days) female Sprague-Dawley rats (n = 8-9 rats/group) were randomly assigned to drink either deionized distilled water (ddH2O) or ddH2O sweetened with 13% (w/v) glucose, sucrose, fructose or high fructose corn syrup 55 (HFCS-55) for 8 weeks. Rats drinking caloric sweetened solutions failed to completely compensate for liquid calories ingested by reducing their consumption of solid food. This resulted in greater total energy intake compared to the ddH2O control; however, there was no significant difference in total energy intake between rats drinking sucrose, fructose or HFCS-55. Of the different caloric sweeteners, only rats drinking HFCS-55 had greater (P glucose solution. This may have occurred because drinking HFCS-55 solution promoted a faster body weight gain. Adiposity induced by caloric sweetened water was not accompanied by metabolic disorders indicated by the absence of dyslipidemia and no differences in fasting serum glucose, insulin or C-peptide among the treatment groups. However, rats drinking HFCS-55 showed lengthened estrous cycles due to prolonged estrus. Based on this study, the type of caloric sweetener added to beverages should be considered when making dietary recommendation for reducing excess body weight and related health risk.

  11. Effect of Short-term Quercetin, Caloric Restriction and Combined Treatment on Age-related Oxidative Stress Markers in the Rat Cerebral Cortex

    Science.gov (United States)

    Alugoju, Phaniendra; Swamy, Vkd Krishan; Periyasamy, Latha

    2018-03-14

    Aging is characterized by gradual accumulation of macromolecular damage leading to progressive loss of physiological function and increased susceptibility to diverse diseases. Effective anti-aging strategies involving caloric restriction or antioxidant supplementation are receiving growing attention to attenuate macromolecular damage in age associated pathology. In the present study, we for the first time investigated the effect of quercetin, caloric restriction and combined treatment (caloric restriction with quercetin) on oxidative stress parameters, acetylcholinesterase and ATPases enzyme activities in the cerebral cortex of aged male Wistar rats. 21 months aged rats were divided into four groups (n=6-8) such as group 1-fed ad libitum (AL); group 2-quercetin supplementation of 50 mg/kg b.w/day for 45 days fed ad libitum (QUER); group 3: caloric restricted (CR) (fed 40% reduced AL for 45 days); group 4-fed 40% CR and 50 mg/kg b.w/day QUER for 45 days (CR + QUER). Group 5-three month age old rats served as young control (YOUNG). Our results demonstrate that combined treatment of caloric restriction and quercetin significantly improved the age associated decline in the activities of endogenous antioxidant enzymes [such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)] and glutathione (GSH) content and attenuated elevated levels of protein carbonyl content (PCC), lipid peroxidation, lipofuscin, reactive oxygen species (ROS), and nitric oxide (NO). Furthermore, it is also observed that combined treatment ameliorated age associated alterations in acetylcholine esterase (AChE) and adenosine triphosphatases (ATPases) such as Na+/K+-ATPase and Ca+2-ATPase (but not Mg+2- ATPase) enzyme activities. Finally, we conclude that combined treatment of caloric restriction and quercetin (but not either treatment alone) in late life is an effective anti-aging therapy to counteract the age related accumulation of oxidative macromolecular damage

  12. Resveratrol and caloric restriction prevent hepatic steatosis by regulating SIRT1-autophagy pathway and alleviating endoplasmic reticulum stress in high-fat diet-fed rats.

    Science.gov (United States)

    Ding, Shibin; Jiang, Jinjin; Zhang, Guofu; Bu, Yongjun; Zhang, Guanghui; Zhao, Xiangmei

    2017-01-01

    Studies have demonstrated that resveratrol (a natural polyphenol) and caloric restriction activate Sirtuin-1 (SIRT1) and induce autophagy. Furthermore, autophagy is induced by the SIRT1-FoxO signaling pathway and was recently shown to be a critical protective mechanism against non-alcoholic fatty liver disease (NAFLD) development. We aimed to compare the effects of resveratrol and caloric restriction on hepatic lipid metabolism and elucidate the mechanism by which resveratrol supplementation and caloric restriction alleviate hepatosteatosis by examining the molecular interplay between SIRT1 and autophagy. Eight-week-old male Wistar rats (40) were divided into four groups: the STD group, which was fed a standard chow diet; the HFD group, which was fed a high-fat diet; HFD-RES group, which was fed a high-fat diet plus resveratrol (200 mg/kg.bw); and the HFD-CR group, which was fed a high-fat diet in portions containing 70% of the mean intake of the HFD group rats. The groups were maintained for 18 weeks. Metabolic parameters, Oil Red O and hematoxylin-eosin staining of the liver, and the mRNA and protein expression of SIRT1, autophagy markers and endoplasmic reticulum(ER) stress-associated genes in the liver were assessed after the 18-week treatment. We found that resveratrol (200 mg/kg bw) and caloric restriction (30%) partially prevented hepatic steatosis and hepatocyte ballooning, increased the expression of SIRT1 and autophagy markers while decreasing ER stress markers in the liver and alleviated lipid metabolism disorder. Moreover, caloric restriction provided superior protection against HFD-induced hepatic fatty accumulation compared with resveratrol and the effects were associated with decreased total energy intake and body weight. We conclude that the SIRT1-autophagy pathway and decreased ER stress are universally required for the protective effects of moderate caloric restriction (30%) and resveratrol (a pharmacological SIRT1 activator) supplementation

  13. Resveratrol and caloric restriction prevent hepatic steatosis by regulating SIRT1-autophagy pathway and alleviating endoplasmic reticulum stress in high-fat diet-fed rats.

    Directory of Open Access Journals (Sweden)

    Shibin Ding

    Full Text Available Studies have demonstrated that resveratrol (a natural polyphenol and caloric restriction activate Sirtuin-1 (SIRT1 and induce autophagy. Furthermore, autophagy is induced by the SIRT1-FoxO signaling pathway and was recently shown to be a critical protective mechanism against non-alcoholic fatty liver disease (NAFLD development. We aimed to compare the effects of resveratrol and caloric restriction on hepatic lipid metabolism and elucidate the mechanism by which resveratrol supplementation and caloric restriction alleviate hepatosteatosis by examining the molecular interplay between SIRT1 and autophagy.Eight-week-old male Wistar rats (40 were divided into four groups: the STD group, which was fed a standard chow diet; the HFD group, which was fed a high-fat diet; HFD-RES group, which was fed a high-fat diet plus resveratrol (200 mg/kg.bw; and the HFD-CR group, which was fed a high-fat diet in portions containing 70% of the mean intake of the HFD group rats. The groups were maintained for 18 weeks. Metabolic parameters, Oil Red O and hematoxylin-eosin staining of the liver, and the mRNA and protein expression of SIRT1, autophagy markers and endoplasmic reticulum(ER stress-associated genes in the liver were assessed after the 18-week treatment. We found that resveratrol (200 mg/kg bw and caloric restriction (30% partially prevented hepatic steatosis and hepatocyte ballooning, increased the expression of SIRT1 and autophagy markers while decreasing ER stress markers in the liver and alleviated lipid metabolism disorder. Moreover, caloric restriction provided superior protection against HFD-induced hepatic fatty accumulation compared with resveratrol and the effects were associated with decreased total energy intake and body weight.We conclude that the SIRT1-autophagy pathway and decreased ER stress are universally required for the protective effects of moderate caloric restriction (30% and resveratrol (a pharmacological SIRT1 activator

  14. Esporotricosis diagnosticada por el laboratorio

    Directory of Open Access Journals (Sweden)

    Nelly Ordóñez

    1989-06-01

    Full Text Available De 1976 a 1989 se han diagnosticado 40 casos de esporotricosis en el laboratorio de Micología del Instituto Nacional de Salud. La enfermedad se presentó en pacientes entre 4 y 52 años y tuvo predilección por el sexo masculino: 35 de 40 (87,5%; las formas clínicas más frecuentes fueron la cutánea fija, 18 de 40 (45%, y la linfocutánea, 17 de 40 (42,5%, con localización mayor en miembros superiores, 18 de 40 (45%. El diagnóstico se estableció por el aislamiento del Sporothrix schenckii en 35 de 38 pacientes (92%; los otros dos pacientes se diagnosticaron empleando otras técnicas: inmunofluorescencia directa, intradermorreacción y aglutinación en tubo.

  15. PREFACE: XVth International Conference on Calorimetry in High Energy Physics (CALOR2012)

    Science.gov (United States)

    Akchurin, Nural

    2012-12-01

    The XVth International Conference on Calorimetry in High Energy Physics, CALOR2012, was held in Santa Fe, New Mexico from 4-8 June 2012. The series of conferences on calorimetry started in 1990 at Fermilab, and they have been the premier event for calorimeter aficionados, a trend that CALOR2012 upheld. This year, several presentations focused on the status of the major calorimeter systems, especially at the LHC. Discussions on new and developing techniques in calorimetry took a full day. Excellent updates on uses of calorimeters or about ideas that are deeply rooted in particle physics calorimetry in astrophysics and neutrino physics were followed by talks on algorithms and special triggers that rely on calorimeters. Finally, discussions of promising current developments and ongoing R&D work for future calorimeters capped the conference. The field of calorimetry is alive and well, as evidenced by the more than 100 attendees and the excellent quality of over 80 presentations. You will find the written contributions in this volume. The presentations can be found at calor2012.ttu.edu. The first day of the conference was dedicated to the LHC. In two invited talks, Guillaume Unal (CERN) and Tommaso Tabarelli de Fatis (Universita' & INFN Milano Bicocca) discussed the critical role electromagnetic calorimeters play in the hunt for the Standard Model Higgs boson in ATLAS and CMS, respectively. The enhanced sensitivity for light Higgs in the two-gamma decay channel renders electromagnetic calorimeters indispensible. Much of the higher mass region was already excluded for the SM Higgs by the time of this conference, and after less than a month, on 4 July, CERN announced the discovery of a new boson at 125 GeV, a particle that seems consistent with the Higgs particle so far. Once again, without the electromagnetic calorimeters, this would not have been possible. Professor Geoffrey West from the Santa Fe Institute gave the keynote address. His talk, 'Universal Scaling Laws

  16. Comparison of Intermittent Fasting Versus Caloric Restriction in Obese Subjects: A Two Year Follow-Up.

    Science.gov (United States)

    Aksungar, F B; Sarıkaya, M; Coskun, A; Serteser, M; Unsal, I

    2017-01-01

    Caloric restriction (CR) is proven to be effective in increasing life span and it is well known that, nutritional habits, sleeping pattern and meal frequency have profound effects on human health. In Ramadan some Muslims fast during the day-light hours for a month, providing us a unique model of intermittent fasting (IF) in humans. In the present study, we have investigated the effects of IF versus CR on the same non-diabetic obese subjects who were followed for two years according to the growth hormone (GH)/Insulin like growth factor (IGF)-1 axis and insulin resistance. Single-arm Interventional Human Study. 23 female subjects (Body Mass Index (BMI) 29-39, aged between 28-42years). Follow-up is designed as 12 months of CR, after which there was a month of IF and 11 months of CR again, to be totally 24 months. Subjects' daily diets were aligned as low calorie diet during CR and during the IF period, the same subjects fasted for 15 hours in a day for a month and there was no daily calorie restriction. Nutritional pattern was changed as 1 meal in the evening and a late supper before sleeping and no eating and drinking during the day light hours in the IF model. Subjects made brisk walking twice a day during the whole follow-up including both CR and IF periods. BMI, Blood glucose, insulin, TSH, GH, HbA1c, IGF-1, Homa-IR and urinary acetoacetate levels were monitored once in three months and twice in the fasting month. While subjects lost 1250 ± 372g monthly during the CR, in the IF period, weight loss was decreased to 473 ± 146 g. BMI of all subjects decreased gradually and as the BMI decreased, glucose, HbA1c, insulin, Homa-IR and TSH levels were decreased. GH levels were at baseline at the beginning, increased in the first six months and stayed steady during the CR and IF period than began decreasing after the IF period, while IGF-I increased gradually during the CR period and beginning with the 7th day of IF period, it decreased and kept on decreasing till the

  17. Restricted versus continued standard caloric intake during the management of refeeding syndrome in critically ill adults: a randomised, parallel-group, multicentre, single-blind controlled trial.

    Science.gov (United States)

    Doig, Gordon S; Simpson, Fiona; Heighes, Philippa T; Bellomo, Rinaldo; Chesher, Douglas; Caterson, Ian D; Reade, Michael C; Harrigan, Peter W J

    2015-12-01

    Equipoise exists regarding the benefits of restricting caloric intake during electrolyte replacement for refeeding syndrome, with half of intensive care specialists choosing to continue normal caloric intake. We aimed to assess whether energy restriction affects the duration of critical illness, and other measures of morbidity, compared with standard care. We did a randomised, multicentre, single-blind clinical trial in 13 hospital intensive care units (ICUs) in Australia (11 sites) and New Zealand (two sites). Adult critically ill patients who developed refeeding syndrome within 72 h of commencing nutritional support in the ICU were enrolled and allocated to receive continued standard nutritional support or protocolised caloric restriction. 1:1 computer-based randomisation was done in blocks of variable size, stratified by enrolment serum phosphate concentration (>0·32 mmol/L vs ≤0·32 mmol/L) and body-mass index (BMI; >18 kg/m(2)vs ≤18 kg/m(2)). The primary outcome was the number of days alive after ICU discharge, with 60 day follow-up, in a modified intention-to-treat population of all randomly allocated patients except those mistakenly enrolled. Days alive after ICU discharge was a composite outcome based on ICU length of stay, overall survival time, and mortality. The Refeeding Syndrome Trial was registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR number 12609001043224). Between Dec 3, 2010, and Aug 13, 2014, we enrolled 339 adult critically ill patients: 170 were randomly allocated to continued standard nutritional support and 169 to protocolised caloric restriction. During the 60 day follow-up, the mean number of days alive after ICU discharge in 165 assessable patients in the standard care group was 39·9 (95% CI 36·4-43·7) compared with 44·8 (95% CI 40·9-49·1) in 166 assessable patients in the caloric restriction group (difference 4·9 days, 95% CI -2·3 to 13·6, p=0·19). Nevertheless, protocolised caloric

  18. Simulación CFD de la transferencia de calor en un reactor de hidrotratamiento de aceites vegetales de segunda generación

    OpenAIRE

    Mendoza Sépulveda, César Camilo

    2013-01-01

    Resumen: Se desarrolló un modelo CFD que permite representar la transferencia de calor en un reactor de hidrotratamiento de aceites vegetales. Este modelo permitió evaluar la transferencia de calor para distintas configuraciones del reactor. En el proceso de hidrotratamiento de aceites vegetales se transforma el aceite en un líquido con cero contenido de azufre y excelentes propiedades como combustible diesel. El proceso se basa en la adición de hidrógeno a alta presión en un reactor de lecho...

  19. Miasis cutanea por cordylobia anthropophaga

    Directory of Open Access Journals (Sweden)

    Alkorta Gurrutxaga Miriam

    2001-01-01

    Full Text Available El incremento progresivo en el número de personas que viajan a países tropicales ha hecho que las enfermedades importadas adquieran una relevancia cada vez mayor. Las miasis (o infestaciones por larvas de moscas cutáneas se encuentran entre este tipo de enfermedades siendo especialmente frecuentes en países tropicales. A propósito de la observación de un caso de miasis cutánea masiva por Cordylobia antropophaga, que ocurrió en una mujer de 34 años de edad al volver de un viaje a Senegal, se ha efectuado una revisión de los casos de miasis cutáneas forunculoides importadas publicados en España, así como de la biología, patología, tratamiento y prevención de la miasis humana por Cordylobia anthropophaga. El caso referido, se caracterizó por la infestación con un número inusualmente elevado de larvas, no sospechándose su etiología hasta la fase final de la enfermedad. La emergencia continuada de larvas (se recogieron 91 generó en la paciente un estado de ansiedad importante. Finalmente, la eliminación de las larvas provocó una rápida mejoría de la paciente. Aunque los casos de miasis cutánea no tienen la gravedad de otras enfermedades importadas, su conocimiento es necesario desde el punto de vista preventivo, diagnóstico y terapeútico. Es importante proceder a la identificación morfológica de las larvas diferenciándolas de otro tipo de miasis con implicaciones terapéuticas diferentes.

  20. Heat transfer equipment performance diagnosis of auxiliary systems in electric power stations; Diagnostico de comportamiento de equipo de transferencia de calor de sistemas auxiliares de centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Esparza Gutierrez, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1990-12-31

    In this article the methodology followed to diagnose the performance of the equipment where heat is transferred from the feed water, condensate and circulation water systems in fossil power plants (FPP). The data collection is made with the unit in normal operation, using local instrumentation without taking the equipment out of service for its installation. The equipment diagnosis is made through the analysis of the collected data in actual operation and the design data; for this purpose a thermal balance of the interested systems is performed to obtain all the conditions an operation data. Later on the performance indicative parameters (PIP) of actual operation and design are calculated and compared one against the other. Such a comparison reveals the performance deterioration and the possible equipment faults. The data obtained and the supplementary information are stored in a data base whose objective is that Comision Federal de Electricidad has on hand a prompt access to them in order to control the performance, compare them among similar units and power stations, and inclusively verify possible recurrent causes of low availability in the referred systems. [Espanol] En este articulo se presenta la metodologia seguida para diagnosticar el comportamiento de equipos en los que se transfiere calor de los sistemas de agua de alimentacion, condensado y circulacion de las centrales termoelectricas (CTE). La toma de datos se realiza con la unidad en operacion normal, utilizando instrumentacion local sin necesidad de sacar de servicio a los equipos para su instalacion, ya que se ocupan los mismos puntos para instrumentos con que cuentan por diseno. El diagnostico de los equipos se realiza mediante el analisis de los datos recopilados, tanto de operacion real como de diseno; para ello, se efectua un balance termico de los sistemas de interes para obtener todas las condiciones y los datos de operacion. Posteriormente, se calculan los parametros indicativos de

  1. Heat transfer equipment performance diagnosis of auxiliary systems in electric power stations; Diagnostico de comportamiento de equipo de transferencia de calor de sistemas auxiliares de centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Esparza Gutierrez, Rogelio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    In this article the methodology followed to diagnose the performance of the equipment where heat is transferred from the feed water, condensate and circulation water systems in fossil power plants (FPP). The data collection is made with the unit in normal operation, using local instrumentation without taking the equipment out of service for its installation. The equipment diagnosis is made through the analysis of the collected data in actual operation and the design data; for this purpose a thermal balance of the interested systems is performed to obtain all the conditions an operation data. Later on the performance indicative parameters (PIP) of actual operation and design are calculated and compared one against the other. Such a comparison reveals the performance deterioration and the possible equipment faults. The data obtained and the supplementary information are stored in a data base whose objective is that Comision Federal de Electricidad has on hand a prompt access to them in order to control the performance, compare them among similar units and power stations, and inclusively verify possible recurrent causes of low availability in the referred systems. [Espanol] En este articulo se presenta la metodologia seguida para diagnosticar el comportamiento de equipos en los que se transfiere calor de los sistemas de agua de alimentacion, condensado y circulacion de las centrales termoelectricas (CTE). La toma de datos se realiza con la unidad en operacion normal, utilizando instrumentacion local sin necesidad de sacar de servicio a los equipos para su instalacion, ya que se ocupan los mismos puntos para instrumentos con que cuentan por diseno. El diagnostico de los equipos se realiza mediante el analisis de los datos recopilados, tanto de operacion real como de diseno; para ello, se efectua un balance termico de los sistemas de interes para obtener todas las condiciones y los datos de operacion. Posteriormente, se calculan los parametros indicativos de

  2. Abdome agudo por obstrução por ileobiliar

    Directory of Open Access Journals (Sweden)

    Márcia Cristina de Alencastro

    Full Text Available OBJETIVO: descrever a experiência na abordagem dos doentes com abdome agudo por obstrução por IB, desde o diagnóstico até o tratamento definitivo. MÉTODOS: estudo retrospectivo incluindo todos os casos de IB tratados em um período de 23 anos. De acordo com a abordagem cirúrgica realizada, os pacientes foram divididos em dois grupos (1 enterolitotomia com colecistectomia no segundo momento; e (2 enterolitotomia, colecistectomia e abordagem da fístula. RESULTADOS: Doze pacientes foram incluídos, sendo 11 mulheres (91,6%, com média de idade de 72,2 anos. Todos os pacientes apresentavam doenças associadas, principalmente hipertensão arterial sistêmica (75%. Dois pacientes não apresentavam sintomas significativos de obstrução intestinal. O diagnóstico de IB foi realizado em seis pacientes (50% antes da laparotomia. O grupo 1 foi constituído de oito pacientes e o grupo 2 de quatro, e a morbidade foi, respectivamente, 33,3% e 8,3%. A mortalidade foi 16,6% (um paciente de cada grupo. CONCLUSÃO: O manejo do IB deve ser individualizado. O tratamento da obstrução mediante remoção do cálculo biliar por enterotomia proximal é a escolha inicial para o tratamento do IB. A colecistectomia e a correção da fístula bilioentérica podem ser realizadas juntamente com a remoção do cálculo, no entanto, em pacientes com comorbidades significativas, esses procedimentos devem ser realizados posteriormente.

  3. Proposta de método de priorização de processos a serem monitorados no controle estatístico de processo: uma aplicação em trocador de calor

    Directory of Open Access Journals (Sweden)

    Eduardo Freitas da Silveira

    2011-03-01

    Full Text Available As empresas visam se solidificar no mercado, para tanto é primordial aumentar a qualidade de seus produtos e serviços. A implementação do controle estatístico do processo tem sido utilizada para atingir este objetivo, porém para obter eficiência é necessário priorizar os processos a serem monitorados. A fim de determinar quais as características do processo devem ser monitoradas buscou-se suporte na função de desdobramento da qualidade, de onde se obtém índices para determinar a prioridade de ação. Após aplicou-se estes índices na Janela de Johari que indicou quais a características fáceis de implementar e que são de alta prioridade. Para elucidar este procedimento foi realizada uma aplicação na fabricação de trocador de calor, de onde se observaram características tais como: comprimento da bengala, acabamento da brasagem, altura do pescoço, que devem ser priorizadas no monitoramento do controle estatístico do processo.

  4. Desajuste educativo por regiones en Colombia: ¿competencia por salarios o por puestos de trabajo?

    Directory of Open Access Journals (Sweden)

    Castillo Caicedo Maribel

    2007-08-01

    Full Text Available Este trabajo aporta una perspectiva del fenómeno de la sobreeducación,
    entendida como un desajuste por exceso, entre el nivel educativo alcanzado
    por el individuo y el exigido por el puesto de trabajo en el cual se
    desempeña; esto se debe a que existe una demanda laboral estrecha de
    puestos de trabajo para personas calificadas en Colombia. Se analizan las
    contribuciones empíricas existentes y el debate sobre las mismas; se
    examinan las teorías que permiten explicar la existencia de un desajuste
    educativo y se realiza una revisión de la literatura internacional y
    nacional sobre el tema. Adicionalmente, se plantean una serie de hipótesis
    para desarrollar un esquema que permita determinar el comportamiento
    del individuo en el fenómeno de la sobreeducación.

  5. Muerte materna por malaria grave por Plasmodium vivax

    Directory of Open Access Journals (Sweden)

    Nancy Arróspide

    Full Text Available Se presenta el caso de una mujer de 19 años con 29 semanas de gestación, procedente de Llumpe (Ancash con antecedentes de viajes a las localidades de Chanchamayo (Junín y Rinconada (Ancash. Ingresó al Hospital de Chacas (Ancash por presentar mal estado general, deshidratación, dificultad respiratoria, ictericia, sensación de alza térmica y dolor abdominal, tuvo reporte de: hemoparásitos 60% en frotis sanguíneo. Fue transferida al Hospital Ramos Guardia (Huaraz donde presentó mayor dificultad respiratoria, coluria, hematuria, disminución del débito urinario y reporte de Plasmodium (+, luego fue transferida al Hospital Cayetano Heredia (Lima donde ingresó a la Unidad de Cuidados Intensivos (UCI, con evolución a falla multiorgánica, óbito fetal y muerte materna. Se confirmó infección por Plasmodium vivax. Destacamos la importancia de mejorar nuestras capacidades de diagnóstico y manejo para brindar un tratamiento adecuado y oportuno.

  6. Miasis ocular por Oestrus ovis

    Directory of Open Access Journals (Sweden)

    María Beltrán F

    2006-01-01

    Full Text Available Se presentan tres casos de miasis ocular (dos adultos y un niñoprocedentes de zonas ganaderas de la provincia de Huaura,departamento de Lima,que acudieron al Hospital Regional de Huacho por presentar el ojo rojo,fotofobia, edema palpebral y sensación de cuerpo extraño;se extrajeron larvas adheridas al canto interno del ojo,las cuales se recibieron en el Instituto Nacional de Salud y fueron identificadas como Oestrus ovis .

  7. Problemas de construcción y de explotación· de los grandes hornos rotatorios por vía seca

    Directory of Open Access Journals (Sweden)

    Münk, R.

    1963-06-01

    Full Text Available Not availableSe indican las consideraciones que han incitado a la industria del cemento a construir grandes unidades de hornos por vía seca. Se describen los métodos que hoy se encuentran en el mercado. Se compara la economía térmica de algunos hornos por vía seca, dedicando especial atención a la recuperación de calor de los gases y al funcionamiento del enfriador. Se explican las enseñanzas características especiales de estas grandes unidades. Se trata de la eliminación de polvo y cuestiones de dosificación del combustible y del crudo, así como problemas del desgaste y de la conservación del precalentador de la chapa del homo y del enfriador. Se discute el consumo de calor teóricamente más económico y se muestran los problemas a resolver para ponerlo en práctica.

  8. Bruising of the esophagus as a cause of gastrointestinal bleeding in a case of heatstroke Hematomas esofágicos como causa de hemorragia digestiva en un caso de golpe de calor

    Directory of Open Access Journals (Sweden)

    A. J. Lucendo Villarín

    2005-08-01

    Full Text Available Alterations in blood clotting are a frequent complication of serious heatstroke and may result in gastrointestinal bleeding. We report the case of a 26-year-old man who was admitted to our hospital with symptoms of hyperthermia associated with encephalopathy and disseminated intravascular coagulation (DIC after prolonged exposure to sunlight. He presented hematemesis, after which he was diagnosed with having a bruising of the esophagus that took up the upper and lower thirds, there being no other lesions in the stomach or duodenum. After supportive treatment and following the resolution of the underlying pathology, the endoscopy-revealed injuries healed with a complete normalization of the esophageal mucosa. Esophageal submucosal bruising is an exceptional cause of hematemesis in serious heatstroke not previously described in the literature.Las alteraciones de la coagulación son una complicación frecuente en el golpe de calor grave, y pueden ser causa de hemorragia digestiva. Presentamos el caso de un varón de 26 años que fue admitido en nuestro hospital por un cuadro de hipertermia, asociado con encefalopatía y coagulación intravascular diseminada tras exposición solar prolongada. Presentó hematemesis por la que fue diagnosticado de múltiples hematomas esofágicos que ocupaban los tercios superior e inferior del órgano, en ausencia de otras lesiones en estómago y duodeno. Tras el tratamiento de soporte y la resolución de la patología subyacente, desaparecieron las lesiones endoscópicas, normalizándose la mucosa esofágica.

  9. 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.

    Science.gov (United States)

    Lv, Mengmeng; Zhu, Xingya; Wang, Hao; Wang, Feng; Guan, Wenxian

    2014-01-01

    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. However, the conclusions are controversial. We aim to review the relevant animal studies systematically and provide assistance for further clinical studies. Literatures on associations between dietary restriction and cancer published in PubMed in recent twenty years were comprehensively searched. Animal model, tumor type, feeding regimen, study length, sample size, major outcome, conclusion, quality assessment score and the interferential step of cancer were extracted from each eligible study. We analyzed the tumor incidence rates from 21 studies about caloric restriction. Fifty-nine studies were involved in our system review. The involved studies explored roles of dietary restriction during initiation, progression and metastasis of cancer. About 90.9% of the relevant studies showed that caloric restriction plays an anti-cancer role, with the pooled OR (95%CI) of 0.20 (0.12, 0.34) relative to controls. Ketogenic diet was also positively associated with cancer, which was indicated by eight of the nine studies. However, 37.5% of the related studies obtained a negative conclusion that intermittent fasting was not significantly preventive against cancer. Caloric restriction and ketogenic diet are effective against cancer in animal experiments while the role of intermittent fasting is doubtful and still needs exploration. More clinical experiments are needed and more suitable patterns for humans should be investigated.

  10. 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.

    Directory of Open Access Journals (Sweden)

    Mengmeng Lv

    Full Text Available 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. However, the conclusions are controversial. We aim to review the relevant animal studies systematically and provide assistance for further clinical studies.Literatures on associations between dietary restriction and cancer published in PubMed in recent twenty years were comprehensively searched. Animal model, tumor type, feeding regimen, study length, sample size, major outcome, conclusion, quality assessment score and the interferential step of cancer were extracted from each eligible study. We analyzed the tumor incidence rates from 21 studies about caloric restriction.Fifty-nine studies were involved in our system review. The involved studies explored roles of dietary restriction during initiation, progression and metastasis of cancer. About 90.9% of the relevant studies showed that caloric restriction plays an anti-cancer role, with the pooled OR (95%CI of 0.20 (0.12, 0.34 relative to controls. Ketogenic diet was also positively associated with cancer, which was indicated by eight of the nine studies. However, 37.5% of the related studies obtained a negative conclusion that intermittent fasting was not significantly preventive against cancer.Caloric restriction and ketogenic diet are effective against cancer in animal experiments while the role of intermittent fasting is doubtful and still needs exploration. More clinical experiments are needed and more suitable patterns for humans should be investigated.

  11. 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.

  12. Effects of aerobic versus resistance exercise without caloric restriction on abdominal fat, intrahepatic lipid, and insulin sensitivity in obese adolescent boys: a randomized, controlled trial

    Science.gov (United States)

    The optimal exercise modality for reductions of abdominal obesity and risk factors for type 2 diabetes in youth is unknown. We examined the effects of aerobic exercise (AE) versus resistance exercise (RE) without caloric restriction on abdominal adiposity, ectopic fat, and insulin sensitivity and se...

  13. The influence of caloric deprivation and food composition on TSH, thyroid hormones and nuclear binding of T3 in mononuclear blood cells in obese women

    DEFF Research Database (Denmark)

    Matzen, L E; Kvetny, J

    1989-01-01

    In vivo changes in thyroid-stimulating hormone (TSH), thyroxin (T4), triiodothyronine (T3) and nuclear binding of T3 (NBT3) in mononuclear blood cells were studied in obese women during seven days of caloric deprivation (maximum 1,100 kcal/d). In seven women given a high protein diet (80% protein...

  14. Time-resolved lateral spin-caloric transport of optically generated spin packets in n-GaAs

    Science.gov (United States)

    Göbbels, Stefan; Güntherodt, Gernot; Beschoten, Bernd

    2018-05-01

    We report on lateral spin-caloric transport (LSCT) of electron spin packets which are optically generated by ps laser pulses in the non-magnetic semiconductor n-GaAs at K. LSCT is driven by a local temperature gradient induced by an additional cw heating laser. The spatio-temporal evolution of the spin packets is probed using time-resolved Faraday rotation. We demonstrate that the local temperature-gradient induced spin diffusion is solely driven by a non-equilibrium hot spin distribution, i.e. without involvement of phonon drag effects. Additional electric field-driven spin drift experiments are used to verify directly the validity of the non-classical Einstein relation for moderately doped semiconductors at low temperatures for near band-gap excitation.

  15. 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)

    1993-12-31

    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.

  16. Uso de dados de Sensoriamento Remoto para identificação de ilhas de calor em Teresina - PI

    Directory of Open Access Journals (Sweden)

    Felipe Ferreira Monteiro

    2012-12-01

    Full Text Available As mudanças climáticas globais são uma das grandes preocupações da atualidade e em áreas urbanas o aumento de temperatura é o fenômeno mais percebido. O trabalho objetiva identificar ilhas de calor em bairros da zona leste de Teresina-PI utilizando dados do satélite Landsat-5, para o ano de 2010. Foi possível verificar a relação entre a densidade construída, o padrão de ocupação e a pouca cobertura vegetal com as áreas de maiores temperatura na área estudada. O estudo demonstrou a influência da urbanização no aumento da temperatura e a necessidade das áreas verdes para minimizar os efeitos das mudanças climáticas.

  17. Distinct lipid profiles predict improved glycemic control in obese, nondiabetic patients after a low-caloric diet intervention

    DEFF Research Database (Denmark)

    Valsesia, Armand; Saris, Wim Hm; Astrup, Arne

    2016-01-01

    BACKGROUND: An aim of weight loss is to reduce the risk of type 2 diabetes (T2D) in obese subjects. However, the relation with long-term glycemic improvement remains unknown. OBJECTIVE: We evaluated the changes in lipid composition during weight loss and their association with long-term glycemic...... improvement. DESIGN: We investigated the plasma lipidome of 383 obese, nondiabetic patients within a randomized, controlled dietary intervention in 8 European countries at baseline, after an 8-wk low-caloric diet (LCD) (800-1000 kcal/d), and after 6 mo of weight maintenance. RESULTS: After weight loss......: In this study, we report a lipid signature of LCD success (for weight and glycemic outcome) in obese, nondiabetic patients. Lipid changes during an 8-wk LCD allowed us to predict insulin-resistant patients after 6 mo of weight maintenance. The determination of the lipid composition during an LCD enables...

  18. Fluxo de calor sensível em cultivo de feijão-caupi Sensible heat flux in cowpea

    Directory of Open Access Journals (Sweden)

    José R. de S Lima

    2011-10-01

    Full Text Available O presente trabalho objetivou comparar o fluxo de calor sensível obtido pelo método do balanço de energia-razão de Bowen (H_B e pelo método aerodinâmico (H_A, em uma área de 4 ha cultivada com feijão-caupi em Areia-PB (6º 58' 12" S e 35º 42' 15" O, 620 m. Foram coletados dados de saldo de radiação, fluxo de calor no solo, temperatura e umidade do solo, temperatura e umidade relativa do ar, velocidade do vento e precipitação pluvial, os quais eram lidos a cada minuto, e armazenados, em uma central de aquisição de dados, como médias a cada 30 min, com exceção da pluviometria, cujo valor foi totalizado no período. Obteve-se excelente concordância entre H_A e H_B, com um índice "d " de 0,980, um erro padrão (EP de 14,88 W m-2, e sem diferença significativa entre H_A e H_B, pelo teste t-Student. Deste modo, o método aerodinâmico pode ser usado em conjunto com medidas de saldo de radiação e de fluxo de calor no solo, para se estimar o fluxo de calor latente e, consequentemente, a evapotranspiração da cultura do feijão-caupi, para as condições edafoclimáticas do Brejo Paraibano.A study was performed to compare the bulk aerodynamic (H_A and Bowen ratio energy balance (H_B methods in the estimation of the sensible heat flux in a cowpea crop. Data of net radiation, soil heat flux, soil water content, soil temperature, air temperature, relative humidity, wind speed and rainfall were collected on 30-min time intervals in an area of 4 ha belonging to the municipality of Areia, PB (6º 58' 12" S e 35º 42' 15" W, 620 m. Results showed that there was a good agreement between H_A and H_B with an index "d" of 0.98 and standard error of estimate (SEE of 14.88 W m-2, no significant difference between H_A H_B, by the t-Student test. Thus, the bulk aerodynamic method can be used in conjunction with measurements of net radiation and soil heat flux to estimate the evapotranspiration of the cowpea under soil and climatic condition of

  19. 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.

  20. 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.

  1. Estudo comparativo do comportamento da costura em tecido que retarda a chama submetida ao calor e à chama

    OpenAIRE

    Sandra Monteiro de Albuquerque

    2013-01-01

    A necessária atenção que se dá à seleção do tecido base da vestimenta de proteção ao calor e ao fogo é, algumas vezes, negligenciada no momento da confecção do produto. Fatores como a terceirização do processo de costura pelas empresas e a inspeção de qualidade somente no seu final, podem dificultar tanto o acompanhamento do processo de confecção, quanto a observação das especificações das normas regulamentadoras, possibilitando produção de vestimentas ineficazes na sua função protetora. A in...

  2. Effects of caloric restriction on learning and recovery of a spatial task in rats exposed to acute stress

    Directory of Open Access Journals (Sweden)

    Lamprea Rodríguez, Marisol

    2009-06-01

    Full Text Available The purpose of the present study was to describe the effects of caloric restriction on spatial learning and recovery in the Barnes maze in animals experimentally stressed before recovery of the spatial task. Male Wistar rats were exposed for two months to one of two conditions: ad libitum (AL or intermittent fasting (IF. Both groups were exposed then to an experimental form of acute stress, induced by movement restriction for 4 hours. IF subjects had better performance in learning tasks during the acquisition trials but required more time to complete the task after the stressor was applied. These results are discussed in light of previous data reported in the literature emphasizing differences in the instruments used to evaluate spatial learning and its interaction with experimentally induced stress.

  3. [Effeciency of usage of natural low caloric protein-vegetable product by patients with excess body weight and hypertension].

    Science.gov (United States)

    Rakhmanov, R S; Istomin, A V; Narutdinov, D A; Kropachev, V Iu

    2014-01-01

    The efficiency of the usage of natural low caloric concentrated protein-vegetable food product (LCCF) by 23 persons with excess body weight at the age of 30-44 years (the 1st group) and 30 hypertensive patients at remission stage and overweight at age 45-59 years old (the 2nd group) has been assessed. According to energy expenditure, all examined male persons were classified to II group of physical activity: PhysicalActivity Coefficient (PAC) was 1,35±0,14 and 1,34±0,22 respectively. As for dietary intake, authors revealed an excess of protein (up to 20,1%), fat (up to 17,2%) and daily caloric content over daily energy expenditure that led to an increase of body weight along with metabolic and liver function disorders. Initially, body mass index (BMI) was 29,9±0,6 kg/m2 in the 1st group and 36,2±0,4 kg/m2 in the 2nd group. LCCFP was administrated to persons in studied groups and consisted of fat-free curd, egg white, rye bran, dried apricots, laminaria, leaves of green tea and cowberry. The product was made by cryogenic technology. LCCFP (35 g) was administrated two times per day instead of breakfast and supper during 15 days. Protein content in 1 portion of LCCFP was 5.2 g, fats -3.8 g, carbohydrates - 16.8 g; energy value - 122 kcal. The decrease of daily caloric content was 1225,5 kilocalories (kcal) in the 1st group and 1071,3 kcal in the 2nd group duringperiod of LCCFP administration; the energy value of the diet amounted to an average of 1420 and 1560 kcal per day. During the study, authors found serum protein indices were constant, but revealed the decrease of the level of glucose (by 15,3-18%), cholesterol (18,8-19%), low density lipoprotein cholesterol (13,9-15,8%), triglycerides (20-26,3%) and alanine aminotransferase (39,7-41,4%) and asparagine aminotransferase (40,6-40,7%) activity. This provided evidence of positive influence of the natural protein-vegetable LCCFP on fat and carbohydrate metabolisms as well as liver function. Also, the decrease of

  4. PREFACE: XIII International Conference on Calorimetry in High Energy Physics (CALOR 2008)

    Science.gov (United States)

    Livan, Michele

    2009-07-01

    The XIII International Conference on Calorimetry in High Energy Physics was held in Pavia, Italy, 26-30 May 2008, picking up the baton from the 2006 Conference in Chicago. The Conference took place in the unique environment of the Theresian Room of the University Library. The attendees were surrounded by over 40 000 books of general interest and culture, and had the opportunity to see precious volumes written by such people as Galileo, Volta and Faraday. The Workshop brought together more than 120 participants, including senior scientists as well as young physicists, confirming the central and ever-growing role of calorimeters in modern particle physics. The development of these detectors, as stressed by Professor Klaus Pretzl in his lectio magistralis, has made it possible to explore new frontiers in physics, and the present scenario is no exception to this rule. With the LHC experiments almost completely installed and ready to take data, the Conference was an ideal chance to review the status of the different projects, whose development has been followed and discussed throughout the entire Calor series, and to show that they are capable of meeting the design specifications. Other highlights were the performance and physics results of calorimeters installed in currently operating experiments. In the session on astrophysics and neutrinos, the contributions confirmed the key role of calorimeters in this sector and demonstrated their growing application even beyond the field of accelerator physics. Considerable time was devoted to the state-of-the-art techniques in the design and operation of the detectors, while the session on simulation addressed the importance of a thorough understanding of the shower development to meet the demanding requirements of present experiments. Finally, on the R&D side, the particle flow and dual read-out concepts confronted the challenges issued by the next generation of experiments. This complex material was reviewed in 83

  5. Effects of caloric deprivation on thyroid hormone tissue uptake and generation of low-T3 syndrome

    International Nuclear Information System (INIS)

    van der Heyden, J.T.M.; Docter, R.; van Toor, H.; Wilson, J.H.P.; Hennemann, G.; Krenning, E.P.

    1986-01-01

    Changes in thyroid hormone metabolism in the low-3,5,3'-triiodothyronine (T 3 ) syndrome cannot be fully explained in all conditions by a decrease in 5'-deiodinase activity. Recent observations showed that in rat hepatocytes iodothyronines are taken up by an active transport mechanism. To investigate whether regulation, i.e., inhibition of active transmembraneous transport for iodothyronines in humans may contribute to the generation of the low-T 3 syndrome, tracer thyroxine (T 4 ) and T 3 kinetic studies were performed in 10 obese subjects before and after 7 days on a 240 kcal diet. Kinetics analyses were performed according to a three-pool model of distribution and metabolism for both T 4 and T 3 . For T 4 kinetics, during caloric deprivation serum total T 4 and plasma pool did not change and production rate and metabolic clearance rate (MCR) were significantly lower. Despite a significantly higher serum free T 4 , the mass transfer rate to the rapidly equilibrating pool (REP) and the slowly equilibrating pool (SEP) diminished significantly, leading to smaller tissue pools. For T 3 kinetics, both serum total T 3 , free T 3 , plasma pool, and production rate diminished significantly, while MCR remained unchanged. These changes cannot be fully explained by a similar decrease of serum free T 3 (only 25%), indicating a diminished transport efficiency for T 3 . In conclusion, during caloric restriction, transport of T 4 and T 3 into tissues is diminished, and this phenomenon is much more pronounced for T 4 transport per se may contribute to low-T 3 production and low-T 3 serum levels due to less substrate (i.e., T 4 ) availability in tissues

  6. Caloric restriction and intermittent fasting alter hepatic lipid droplet proteome and diacylglycerol species and prevent diabetes in NZO mice.

    Science.gov (United States)

    Baumeier, Christian; Kaiser, Daniel; Heeren, Jörg; Scheja, Ludger; John, Clara; Weise, Christoph; Eravci, Murat; Lagerpusch, Merit; Schulze, Gunnar; Joost, Hans-Georg; Schwenk, Robert Wolfgang; Schürmann, Annette

    2015-05-01

    Caloric restriction and intermittent fasting are known to improve glucose homeostasis and insulin resistance in several species including humans. The aim of this study was to unravel potential mechanisms by which these interventions improve insulin sensitivity and protect from type 2 diabetes. Diabetes-susceptible New Zealand Obese mice were either 10% calorie restricted (CR) or fasted every other day (IF), and compared to ad libitum (AL) fed control mice. AL mice showed a diabetes prevalence of 43%, whereas mice under CR and IF were completely protected against hyperglycemia. Proteomic analysis of hepatic lipid droplets revealed significantly higher levels of PSMD9 (co-activator Bridge-1), MIF (macrophage migration inhibitor factor), TCEB2 (transcription elongation factor B (SIII), polypeptide 2), ACY1 (aminoacylase 1) and FABP5 (fatty acid binding protein 5), and a marked reduction of GSTA3 (glutathione S-transferase alpha 3) in samples of CR and IF mice. In addition, accumulation of diacylglycerols (DAGs) was significantly reduced in livers of IF mice (P=0.045) while CR mice showed a similar tendency (P=0.062). In particular, 9 DAG species were significantly reduced in response to IF, of which DAG-40:4 and DAG-40:7 also showed significant effects after CR. This was associated with a decreased PKCε activation and might explain the improved insulin sensitivity. In conclusion, our data indicate that protection against diabetes upon caloric restriction and intermittent fasting associates with a modulation of lipid droplet protein composition and reduction of intracellular DAG species. Copyright © 2015. Published by Elsevier B.V.

  7. Curcumin Mimics the Neurocognitive and Anti-Inflammatory Effects of Caloric Restriction in a Mouse Model of Midlife Obesity.

    Directory of Open Access Journals (Sweden)

    Marjana Rahman Sarker

    Full Text Available Dietary curcumin was studied for its potential to decrease adiposity and reverse obesity- associated cognitive impairment in a mouse model of midlife sedentary obesity. We hypothesized that curcumin intake, by decreasing adiposity, would improve cognitive function in a manner comparable to caloric restriction (CR, a weight loss regimen. 15-month-old male C57BL/6 mice were assigned in groups to receive the following dietary regimens for 12 weeks: (i a base diet (Ain93M fed ad libitum (AL, (ii the base diet restricted to 70% of ad libitum (CR or (iii the base diet containing curcumin fed AL (1000 mg/kg diet, CURAL. Blood markers of inflammation, interleukin 6 (IL-6 and C-reactive protein (CRP, as well as an indicator of redox stress (GSH: GSSG ratio, were determined at different time points during the treatments, and visceral and subcutaneous adipose tissue were measured upon completion of the experiment. After 8 weeks of dietary treatment, the mice were tested for spatial cognition (Morris water maze and cognitive flexibility (discriminated active avoidance. The CR group showed significant weight loss and reduced adiposity, whereas CURAL mice had stable weight throughout the experiment, consumed more food than the AL group, with no reduction of adiposity. However, both CR and CURAL groups took fewer trials than AL to reach criterion during the reversal sessions of the active avoidance task, suggesting an improvement in cognitive flexibility. The AL mice had higher levels of CRP compared to CURAL and CR, and GSH as well as the GSH: GSSG ratio were increased during curcumin intake, suggesting a reducing shift in the redox state. The results suggest that, independent of their effects on adiposity; dietary curcumin and caloric restriction have positive effects on frontal cortical functions that could be linked to anti-inflammatory or antioxidant actions.

  8. Acute effects of different diet compositions on skeletal muscle insulin signalling in obese individuals during caloric restriction

    Science.gov (United States)

    Wang, Cecilia C.L.; Adochio, Rebecca L.; Leitner, J. Wayne; Abeyta, Ian M.; Draznin, Boris; Cornier, Marc-Andre

    2012-01-01

    Objective The cellular effects of restricting fat versus carbohydrate during a low-calorie diet are unclear. The aim of this study was to examine acute effects of energy and macronutrient restriction on skeletal muscle insulin signalling in obesity. Materials/Methods Eighteen obese individuals without diabetes underwent euglycemic-hyperinsulinemic clamp and skeletal muscle biopsy after: (a) 5 days of eucaloric diet (30% fat, 50% carbohydrate), and (b) 5 days of a 30% calorie-restricted diet, either low fat/high carbohydrate (LF/HC: 20% fat, 60% carbohydrate) or high-fat/low carbohydrate (HF/LC: 50% fat, 30% carbohydrate). Results Weight, body composition, and insulin sensitivity were similar between groups after eucaloric diet. Weight loss was similar between groups after hypocaloric diet, 1.3 ± 1.3 kg (pdiet. Skeletal muscle of the LF/HC group had increased insulin-stimulated tyrosine phosphorylation of IRS-1, decreased insulin-stimulated Ser 307 phosphorylation of IRS-1, and increased IRS-1-associated phosphatidylinositol (PI)3-kinase activity. Conversely, insulin stimulation of tyrosine phosphorylated IRS-1 was absent and serine 307 phosphorylation of IRS-1 was increased on HF/LC, with blunting of IRS-1-associated PI3-kinase activity. Conclusion Acute caloric restriction with a LF/HC diet alters skeletal muscle insulin signalling in a way that improves insulin sensitivity, while acute caloric restriction with a HF/LC diet induces changes compatible with insulin resistance. In both cases, ex vivo changes in skeletal muscle insulin signalling appear prior to changes in whole body insulin sensitivity. PMID:23174405

  9. Prefrontal cortex, caloric restriction and stress during aging: studies on dopamine and acetylcholine release, BDNF and working memory.

    Science.gov (United States)

    Del Arco, Alberto; Segovia, Gregorio; de Blas, Marta; Garrido, Pedro; Acuña-Castroviejo, Dario; Pamplona, Reinald; Mora, Francisco

    2011-01-01

    This study was designed to investigate whether long-term caloric restriction during the life span of the rat changes the effects of an acute mild stress on the release of dopamine and acetylcholine in the prefrontal cortex (PFC) and on working memory performance. Spontaneous motor activity was also monitored and levels of BDNF measured in the prefrontal cortex, amygdala and hippocampus. Male Wistar rats (3 months of age) were housed during 3, 12, 21 and 27 months (6, 15, 24 and 30 months of age at the end of housing) in caloric restriction (CR; 40% food intake restriction) or control conditions. After behavioural testing, animals were further subdivided into two other groups. In one of the groups BDNF protein levels were determined. In the other group rats were implanted with guide cannulas into the PFC to perform microdialysis experiments. In CR rats the release of dopamine produced by handling stress did not differ from the response found in control rats of 6, 15 and 24 months of age. The release of acetylcholine was not changed at the ages of 6 and 15 months but reduced at the age of 24 months. Stress did not change dopamine or acetylcholine release in CR and control rats of 30 months of age. BDNF levels were increased in the hippocampus and amygdala, but not in the PFC, of 6 and 15 months CR rats. Spontaneous motor activity was increased in all groups of CR rats. Age, however, decreased motor activity in CR and control rats. Both experimental groups showed similar working memory performance in a delayed alternation task in basal conditions and after a situation of acute stress. These results suggest that CR does not modify the function of the PFC in response to an acute stress nor the changes found as a result of the normal process of aging. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Liquid meal composition, postprandial satiety hormones, and perceived appetite and satiety in obese women during acute caloric restriction.

    Science.gov (United States)

    Heden, Timothy D; Liu, Ying; Sims, Lauren; Kearney, Monica L; Whaley-Connell, Adam T; Chockalingam, Anand; Dellsperger, Kevin C; Fairchild, Timothy J; Kanaley, Jill A

    2013-04-01

    The purpose of this study was to compare postprandial satiety regulating hormone responses (pancreatic polypeptide (PP) and peptide tyrosine tyrosine (PYY)) and visual analog scale- (VAS) assessed perceived appetite and satiety between liquid high-protein (HP) and high-carbohydrate (HC) meals in obese women during acute (24-h) caloric restriction. Eleven obese premenopausal women completed two conditions in random order in which they consumed 1500 calories as six 250-calorie HP meals or six 250-calorie HC meals over a 12-h period. Blood samples were taken at baseline and every 20 min thereafter and analyzed for PP and PYY concentrations. At these same points, perceived hunger and fullness were assessed with a VAS. The incremental area under the curve (iAUC) was used to compare postprandial responses. The 12-h PP and PYY iAUC were greater (P≤0.05) during the HP condition (PP: 4727±1306 pg/ml×12 h, PYY: 1373±357 pg/ml×12 h) compared with the HC condition (PP: 2300±528 pg/ml×12 h, PYY: 754±246 pg/ml×12 h). Perceived hunger and fullness were not different between conditions (P>0.05). The greatest changes in PYY and perceived fullness occurred after the morning meals during both conditions. These data suggest that in obese women during acute caloric restriction before weight loss, i) liquid HP meals, compared with HC meals, result in greater postprandial PP and PYY concentrations, an effect not associated with differential appetite or satiety responses, and ii) meal-induced changes in PYY and satiety are greatest during the morning period, regardless of dietary macronutrient composition.

  11. 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

  12. 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.

  13. Effects of caloric intake timing on insulin resistance and hyperandrogenism in lean women with polycystic ovary syndrome.

    Science.gov (United States)

    Jakubowicz, Daniela; Barnea, Maayan; Wainstein, Julio; Froy, Oren

    2013-11-01

    In women with PCOS (polycystic ovary syndrome), hyperinsulinaemia stimulates ovarian cytochrome P450c17α activity that, in turn, stimulates ovarian androgen production. Our objective was to compare whether timed caloric intake differentially influences insulin resistance and hyperandrogenism in lean PCOS women. A total of 60 lean PCOS women [BMI (body mass index), 23.7±0.2 kg/m²] were randomized into two isocaloric (~1800 kcal; where 1 kcal≈4.184 J) maintenance diets with different meal timing distribution: a BF (breakfast diet) (980 kcal breakfast, 640 kcal lunch and 190 kcal dinner) or a D (dinner diet) group (190 kcal breakfast, 640 kcal lunch and 980 kcal dinner) for 90 days. In the BF group, a significant decrease was observed in both AUC(glucose) (glucose area under the curve) and AUC(insulin) (insulin area under the curve) by 7 and 54% respectively. In the BF group, free testosterone decreased by 50% and SHBG (sex hormone-binding globulin) increased by 105%. GnRH (gonadotropin-releasing hormone)-stimulated peak serum 17OHP (17α-hydroxyprogesterone) decreased by 39%. No change in these parameters was observed in the D group. In addition, women in the BF group had an increased ovulation rate. In lean PCOS women, a high caloric intake at breakfast with reduced intake at dinner results in improved insulin sensitivity indices and reduced cytochrome P450c17α activity, which ameliorates hyperandrogenism and improves ovulation rate. Meal timing and distribution should be considered as a therapeutic option for women with PCOS.

  14. Productivity of determinate growth tomato lines tolerant to heat under the organic system Produtividade de linhagens de tomate rasteiro tolerantes ao calor sob o sistema orgânico

    Directory of Open Access Journals (Sweden)

    Cândido A da Costa

    2011-12-01

    Full Text Available The objective of the present work was to evaluate the productive response of heat tolerant lines of determinate growth tomato under the organic production system. The experiment was carried out in the Instituto de Ciências Agrárias of UFMG, Montes Claros, Minas Gerais state, Brazil. The experimental design was of randomized complete blocks with eight treatments and four replications. The treatments consisted of eight heat tolerant processing type tomato lines obtained from the Asian Vegetable Research and Development Center (AVRDC, China: CLN1621L, CLN1621F, CLN1621E, CLN1466P, CLN2026E, CLN2026D, CLN2026C and CLN2001C. There was an inverse relationship between the average weight of the fruits and the number of fruits per plant. The highest average fruit weight of some lines was compensated by the lowest quantity of fruits, in such a way that there were no significant differences among the lines. Symptoms of nutritional deficiency and incidences of pests and diseases were not verified in any of the studied lines. All lines presented potential for genetic improvement research and cultivation using organic production systems under higher temperature conditions.O objetivo do presente trabalho foi avaliar o desempenho produtivo de linhagens de tomate rasteiro tolerantes ao calor sob o sistema orgânico de produção. O experimento foi realizado no Núcleo de Ciências Agrárias da UFMG, Montes Claros-MG. Foi utilizado o delineamento em blocos casualizados com oito tratamentos e quatro repetições. Os tratamentos consistiram de oito linhagens de tomate do tipo rasteiro tolerantes ao calor obtidos na Asian Vegetable Research and Development Center (AVRDC, China: CLN1621L, CLN1621F, CLN1621E, CLN1466P, CLN2026E, CLN2026D, CLN2026C e CLN2001C. Houve uma relação inversa entre o peso médio dos frutos e o número de frutos produzidos por planta. O maior peso médio de frutos de algumas linhagens foi compensado pelo menor número de frutos, de tal

  15. 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.

  16. Hipoglucemia inducida por carcinoma adrenal

    Directory of Open Access Journals (Sweden)

    Jimena Soutelo

    2013-08-01

    Full Text Available El carcinoma suprarrenal es una neoplasia maligna infrecuente y de mal pronóstico. La presentación clínica más común es originada por la producción hormonal excesiva, mientras que el desarrollo de hipoglucemia sintomática es excepcional. Presentamos el caso de una mujer de 37 años que ingresó al hospital por síntomas de hipoglucemias graves, hipertensión arterial, hipopotasemia y amenorrea secundaria. En el laboratorio se halló hipoglucemia con insulina inhibida y niveles de andrógenos en rango tumoral. La tomografía computarizada (TC de abdomen y pelvis mostró voluminosa formación heterogénea de aspecto sólido sin plano de clivaje con respecto al parénquima hepático e intenso realce con contraste. Luego de la extirpación de la masa retroperitoneal, evolucionó con valores de glucemia y potasemia normales, estabilizó la presión arterial y recuperó los ciclos menstruales.

  17. La curiosidad por la naturaleza

    Directory of Open Access Journals (Sweden)

    José Vicente Rodríguez

    2016-07-01

    Full Text Available Esta actitud es un instrumento estratégico para estimular procesos de desarrollo realmente sostenibles, donde se aproveche la admiración que nos embarga al conocer y apreciar lo que nos rodea para responsablemente utilizar y conservar nuestros recursos naturales. Con esta reflexión deseo resaltar esa motivación de escudriñar lo desconocido, que fue también la virtud que propició el desarrollo de la personalidad de Francisco José de Caldas y Tenorio, uno de nuestros primeros y connotados sabios colombianos, y en cuyo honor se constituyó la revista de divulgación científica más importante del país, que en estos momentos cumple 76 años de existencia. Caldas tuvo curiosidad por todo lo que existía en su entorno; inicialmente en su natal Popayán, donde se maravilló por lo natural, lo que lo motivó y llevó más allá de su tierra a formar parte de la mayor empresa de exploración científica adelantada en ese entonces en territorio americano: la primera Expedición Botánica al nuevo Reino de Granada, de José Celestino Mutis.

  18. Junções de materiais dissimilares utilizando o processo de soldagem por fricção rotativa

    OpenAIRE

    Eder Paduan Alves

    2010-01-01

    O objetivo desse trabalho é o desenvolvimento de junções no estado sólido de materiais dissimilares alumínio AA 1050 e aço inoxidável AISI 304, que possam ser utilizadas nas tubulações de reservatórios de propelentes líquidos e demais tubulações dos Veículos Lançadores de Satélites. As junções foram obtidas pelo processo de soldagem por fricção rotativa convencional, que combina o calor gerado entre o atrito de duas superfícies e deformação mecânica. Foram realizados testes de soldagem com di...

  19. Respuesta inmune y expresión de genes en el camarón blanco (Litopenaeus vannamei) inducida por inmunoestimulantes microbianos

    OpenAIRE

    Moreno Herrera, Jesús Tomás

    2014-01-01

    En este trabajo se evaluó el efecto inmunoestimulante de bacterias ácido lácticas y levaduras muertas por calor en Litopenaeus vannamei, cultivado en el laboratorio. La mezcla inmunoestimulante (MI) en polvo se adicionó en el alimento. Se realizó un bioensayo de 26 días en tinas de plástico con 80 L de agua de mar filtrada, aireación constante y 10 organismos por tina. La alimentación se realizó dos veces al día, la limpieza diariamente y la determinación de parámetros fisicoquímicos cada 3 d...

  20. Mortalidad por meningitis por Pasteurella canis. Oportunidades de aprendizaje

    Directory of Open Access Journals (Sweden)

    Ana Rosa Ropero Vera

    2016-01-01

    Full Text Available La meningitis bacteriana es una enfermedad importante de distribución mundial, causa mayor y sustancial de mortalidad y morbilidad en países en desarrollo. La Organización Mundial de la Salud (OMS sostiene que la meningitis es una de las diez afecciones principales del ser humano y debe ser considerada como una emergencia infectológica; por eso es fundamental reconocer que esta enfermedad es causa de muerte en niños de todo el mundo, sin distinción de raza, nivel económico o sociocultural. Se realizó una investigación de caso en menor de 53 días de nacido, que cumplía con los criterios clínicos y de laboratorio compatible con meningitis bacteriana, con el propósito de analizar y fortalecer la toma de decisiones en salud pública por parte de la secretaría local de salud del municipio de Valledupar (Colombia. Entre los hallazgos se encontró antecedentes infecciosos en el menor, coloración de Gram y cultivo de LCR, en el que se identificó cocobacilos Gram negativos, que fueron aislados como agente causal Pasteurella canis. Este estudio pretende sensibilizar a los prestadores de salud para que cuenten con personal altamente capacitado para brindar tratamientos adecuados y prevenir complicaciones en la meningitis bacteriana en niños, y así disminuir la posibilidad de secuelas o muerte, tanto en pacientes con compromiso inmunológico o sin este.

  1. Liberação de resíduos ligados de atrazina de solos por meio de esterilização por autoclavagem e radiação gama

    Directory of Open Access Journals (Sweden)

    L. E. Nakagawa

    1997-12-01

    Full Text Available Para estudar a influência de microrganismos nos processos de dissipação de pesticidas em solos, os métodos de esterilização são, particularmente, importantes. Este trabalho, realizado nos laboratórios do Instituto Biológico de São Paulo, em agosto de 1996, avaliou a influência de dois métodos de esterilização de solo - calor úmido (autoclavagem e radiação γ - no processo de liberação de resíduos ligados. Tomaram-se, como exemplos, resíduos ligados do herbicida atrazina em dois tipos de solo (gley húmico e latossolo vermelho-escuro. Nas amostras de solo submetidas à esterilização por calor úmido, a recuperação dos resíduos previamente ligados como resíduos reextraíveis foi de 5,0 e 5,9 vezes superior à dos controles, não submetidos a qualquer processo de esterilização. Portanto, o próprio método de esterilização liberou os resíduos, o que indica que, para estudar a influência de microrganismos na liberação de resíduos ligados, a autoclavagem não é o método mais adequado. Por outro lado, verificou-se que a radiação γ não alterou a recuperação dos resíduos em relação aos controles.

  2. Heat losses estimation associated with the physical state of the thermal insulation of pipes vaporductos network in Cerro Prieto geothermal field; Estimacion de perdidas de calor asociadas al estado fisico del aislamiento termico de las tuberias de la red de vaporductos del campo geotermico Cerro Prieto

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-11-15

    The Cerro Prieto Geothermal Field (CPGF) steam transportation network is constituted by 140 km of pipes with diameters ranging from 8 to 48 inches, which transport the steam of 165 producing wells to 13 power plants which have a total installed capacity of 720 MWe. Originally, the pipes are thermally insulated with a mineral wool or fiber glass layer and an external aluminum or iron cover. Due to the insulation material has been exposed to weather conditions during the field operation it shows nowadays different grades of wear-out, or even it is lacking in some parts of the network, causing higher heat losses from the pipes to the environment. In this work, the magnitude of the heat losses related with the present condition of the thermal insulation throughout the pipeline network is assessed. This involved determining the longitude and diameter, as well as the insulation condition of each single pipeline section, and the calculation of the heat transfer coefficients for the different thermal insulation conditions defined for this study. [Spanish] La red de transporte de vapor del campo geotermico Cerro Prieto (CGCP) esta constituida por aproximadamente 140 km de tuberias de 8 a 48 pulgadas de diametro, las cuales conducen el vapor producido por 165 pozos hacia 13 plantas generadoras, cuya capacidad instalada es de 720 MWe. Originalmente, estas tuberias son aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion exterior de aluminio o hierro. Debido principalmente al impacto de las condiciones meteorologicas durante el tiempo de operacion del campo, en algunas porciones de la red el aislante presenta actualmente distintos grados de deterioro, o incluso se encuentra ausente, lo cual se traduce en una mayor perdida de calor desde las tuberias hacia el medio ambiente. En el presente trabajo se evalua la magnitud de las perdidas de calor asociadas al estado fisico del aislamiento termico de las

  3. Abundance, biomass and caloric content of Chukchi Sea bivalves and association with Pacific walrus (Odobenus rosmarus divergens) relative density and distribution in the northeastern Chukchi Sea

    Science.gov (United States)

    Young, Jordann K.; Black, Bryan A.; Clarke, Janet T.; Schonberg, Susan V.; Dunton, Kenneth H.

    2017-10-01

    The northeastern Chukchi Sea is a shallow subarctic shelf ecosystem that supports a substantial benthic infaunal community of which bivalves are a major component. We assessed the patterns in population abundance, biomass, and caloric content of ten dominant bivalve taxa in relation to the distribution of the upper trophic level consumer Pacific walrus (Odobenus rosmarus divergens). Bivalves were collected over four cruises in the northeastern Chukchi Sea (2009, 2010, 2012, 2013). Our samples were largely dominated by calorie-dense, deposit-feeding species, including Macoma spp., Ennucula tenuis, Nuculana spp. and Yoldia spp. Weight-frequency distributions were strongly right-skewed for most taxa, though some showed evidence of a bimodal distribution. Caloric densities as measured through bomb calorimetry significantly differed among taxa (ANOVA F = 32.57, df = 9, p-valueanimal wet weight was found to be a reliable predictor of whole animal caloric content. Bivalve populations and peak caloric densities were centered on and to the southeast of Hanna Shoal, which coincided with peak Pacific walrus relative density (walruses per km surveyed) from July through October. Significant differences in mean caloric values were found between areas with and without walruses present (student's t-test, t=-2.9088, df = 252.24, p-value = 0.003952), as well as between areas with low and high walrus relative densities in the pooled annual dataset and in each individual month except October (ANOVA, p-value<0.05). The high-calorie deposit feeders that dominate these bivalve communities preferentially consume food sources, such as sea ice algae, that are likely to be affected by shifting sea ice dynamics. As such, continued warming has the potential to alter bivalve communities in the northeastern Chukchi Sea, which may have profound implications for upper trophic levels.

  4. 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.

  5. Mortalidad intrahospitalaria por accidente cerebrovascular

    Directory of Open Access Journals (Sweden)

    Federico Rodríguez Lucci

    2013-08-01

    Full Text Available La mortalidad global por accidente cerebrovascular (ACV ha disminuido en las últimas tres décadas, probablemente debido a un mejor control de los factores de riesgo vascular. La mortalidad hospitalaria por ACV ha sido tradicionalmente estimada entre 6 y 14% en la mayoría de las series comunicadas. Sin embargo, los datos de ensayos clínicos recientes sugieren que esta cifra sería sustancialmente menor. Se revisaron datos de pacientes internados con diagnóstico de ACV del Banco de Datos de Stroke de FLENI y los registros institucionales de mortalidad entre los años 2000 y 2010. Los subtipos de ACV isquémicos se clasificaron según criterios TOAST y los ACV hemorrágicos en hematomas intrapanquimatosos, hemorragias subaracnoideas aneurismáticas, malformaciones arteriovenosas y otros hematomas intraparenquimatosos. Se analizaron 1514 pacientes, 1079 (71% con ACV isquémico (grandes vasos 39%, cardioembólicos 27%, lacunares 9%, etiología indeterminada 14%, otras etiologías 11% y 435 (29% con ACV hemorrágico (intraparenquimatosos 27%, hemorragia subaracnoidea 30%, malformaciones arteriovenosas 25% y otros hematomas espontáneos 18%. Se registraron 38 muertes intrahospitalarias (17 ACV isquémicos y 21 ACV hemorrágicos, representando una mortalidad global del 2.5% (1.7% en ACV isquémicos y 4.8% en ACV hemorrágicos. No se registraron muertes asociadas al uso de fibrinolíticos endovenosos. La mortalidad intrahospitalaria en pacientes con ACV isquémico y hemorrágico en nuestro centro fue baja. El manejo en un centro dedicado a las enfermedades neurológicas y el enfoque multidisciplinario por personal médico y no médico entrenado en el cuidado de la enfermedad cerebrovascular podrían explicar, al menos en parte, estos resultados.

  6. TEMPERATURE AND HEAT FLOW WHEN TAPPING OF THE HARDENED STEEL USING DIFFERENT COOLING SYSTEMS TEMPERATURA Y FLUJO DE CALOR AL ROSCAR CON MACHOS ACERO ENDURECIDO UTILIZANDO DIVERSOS SISTEMAS DE LUBRICACIÓN

    Directory of Open Access Journals (Sweden)

    Lincoln Cardoso Brandão

    2009-08-01

    la probeta de prueba a 3.0, 7.0 y 11.0 mm desde la entrada del roscado. Se hacen dos réplicas del registro de la temperatura para cada condición de corte ensayada. Se utilizan un modelo teórico-analítico de conducción de calor para evaluar la temperatura en la interfase de la probeta de prueba, determinar el flujo de calor y el coeficiente de convección. El menor incremento de la temperatura y del calor se observa al utilizar el método lubricante en grandes cantidades, seguido por el de MQF, al comparar con la condición en seco. El efecto es directamente proporcional a la cantidad de lubricante aplicado, siendo también significativo con el sistema MQF al compararlo con el corte en seco.

  7. Herida precordial por arma blanca

    OpenAIRE

    Marcelo F. Jiménez; Nuria Novoa; José Luis Aranda; Gonzalo Varela

    2005-01-01

    Varón de 42 años con esquizofrenia paranoide. Intento de suicidio con tres autolesiones por arma blanca (Fig. 1). Fue traído al hospital en estado consciente, taquicárdico, taquipneico y con tensión arterial (TA) de 140/90 mmHg. Fue trasladado al quirófano, donde se practicó una toracotomía axilar izquierda sin extraer el arma. Durante la intervención se apreciaron tres heridas incisas, dos no penetrantes, hemotórax de 150 ml, herida pericárdica de 4 cm, sin lesiones cardíacas. La hoja del ar...

  8. Metal pollution (Pb, Zn, Ni and Cr) in air, road and soil sediment in a high traffic area; Contaminacion por metales (Pb, Zn, Ni y Cr) en aire, sedimentos viales y suelo en una zona de alto trafico vehicular

    Energy Technology Data Exchange (ETDEWEB)

    Manchado, Anali; Garcia, Neyma; Garcia, Cezar; Acosta, Lorena; Cordova, Alberto; Linares, Maria; Giraldoth, Debora [Centro de Investigaciones CEDEGAS, Facultad de Ingenieria, Universidad del Zulia, Maracaibo (Venezuela)]. E-mail: analimachado@yahoo.com; amachadop@luz.edu.ve; Velasquez, Harvi [Facultad Experimental de Ciencias, Universidad del Zulia, Maracaibo (Venezuela)

    2008-11-15

    sequia y de lluvia, empleando un muestreador de bajo volumen con filtros de fibra de cuarzo -para las muestras de PM10- con una frecuencia de una muestra cada tres dias para un total de 26; para los sedimentos viales y suelo fueron colectadas tres muestras con una frecuencia de 15 dias para un periodo de medicion de mes y medio en epoca seca. Todas las muestras fueron sometidas a un proceso de digestion y analizadas por espectrometria de absorcion atomica. Las concentraciones de las PM10 resultaron 2 veces mas altas en la zona de emision que en la zona de dispersion durante ambas epocas climatologicas, presentando una mejor correlacion entre las zonas para epoca de sequia. Todos los metales analizados presentaron diferencias estadisticamente significativas entre las zonas de muestreo. Por otra parte, para el periodo global existen diferencias significativas entre las zonas y las epocas climatologicas tanto para PM10 como para la totalidad de los metales. El Pb no excedio el estandar de calidad del aire establecido para Venezuela, pero su concentracion promedio en la zona de emision fue de 1.13 {mu}g/m{sup 3}, muy cercano al limite diario permitido en Venezuela y por la EPA; por su parte, tanto Pb como Ni sobrepasaron el limite permisible de la Organizacion Mundial de la Salud (OMS) en ambas zonas durante todo el periodo de muestreo. Para las muestras de sedimento y de suelo se encontraron concentraciones significativamente elevadas de Pb, Zn, Ni y Cr en comparacion con la muestra testigo. Los niveles hallados de Pb y Zn estan por encima de los limites permitidos por el decreto 2635 de la normativa venezolana y la EPA, clasificandose la zona como suelo con alta contaminacion por metales pesados. Adicionalmente, el analisis estadistico demostro la adecuada seleccion de la zona de monitoreo, confirmando que la principal fuente de emision de los contaminantes es el parque automotor.

  9. IMAGENS NO CALOR DA HORA OU A FÊNIX RENASCIDA DA IMAGEM DOCUMENTAL

    Directory of Open Access Journals (Sweden)

    Kati Caetano

    2008-12-01

    Full Text Available Apesar da freqüente discussão, tanto nos meios acadêmicos quanto nos midiáticos, envolvendo a crise da imagem documental, na esteira da propalada crise da cultura documental como um todo, não há como negar a proliferação de imagens e o incremento de uma produção assumida com esse propósito no universo das relações comunicacionais, seja ele impresso ou digital. Se, no domínio da arte, a ação hegemônica contemporânea consiste na desestabilização figurativa das imagens, do lado das mídias de produção massiva, afirma-se a sua estabilização como condiçãofundante do ato de documentar. Este trabalho não visa abordar as várias concepções de documental, porque parte do pressuposto de que esse aspecto se apresenta como resultado de estratégias figurativo-enunciativas de “fazer crer”, responsáveis por múltiplos regimes de sentido. De suas escolhas e agenciamentos decorrem modalidades interacionais amparadas na mediatez ou imediatez dos processos compreensivos, num sistema de valores condicionantes do ato comunicativo que coloca em evidência as funções prática, cognitiva, afetiva ou fiduciária (calcada em regimes de crençadas mediações simbólicas. A questão mais geral que norteia opresente texto é indagar como as diferentes mídias, do fotográfico ao virtual, operam com essas imagens e que tipos de implicações comunicacionais promovem.

  10. Imagens no calor da hora ou a Fênix renascida da imagem documental

    Directory of Open Access Journals (Sweden)

    Kati Caetano

    2008-12-01

    Full Text Available Apesar da freqüente discussão, tanto nos meios acadêmicos quanto nos midiáticos, envolvendo a crise da imagem documental, na esteira da propalada crise da cultura documental como um todo, não há como negar a proliferação de imagens e o incremento de uma produção assumida com esse propósito no universo das relações comunicacionais, seja ele impresso ou digital. Se, no domínio da arte, a ação hegemônica contemporânea consiste na desestabilização figurativa das imagens, do lado das mídias de produção massiva, afirma-se a sua estabilização como condição fundante do ato de documentar. Este trabalho não visa abordar as várias concepções de documental, porque parte do pressuposto de que esse aspecto se apresenta como resultado de estratégias figurativo-enunciativas de “fazer crer”, responsáveis por múltiplos regimes de sentido. De suas escolhas e agenciamentos decorrem modalidades interacionais amparadas na mediatez ou imediatez dos processos compreensivos, num sistema de valores condicionantes do ato comunicativo que coloca em evidência as funções prática, cognitiva, afetiva ou fiduciária (calcada em regimes de crença das mediações simbólicas. A questão mais geral que norteia o presente texto é indagar como as diferentes mídias, do fotográfico ao virtual, operam com essas imagens e que tipos de implicações comunicacionais promovem.

  11. Miotoxicidade por organofosforados Organophosphate myotoxicity

    Directory of Open Access Journals (Sweden)

    Maria J. Cavaliere

    1996-06-01

    Full Text Available Os organofosforados são um grupo de compostos químicos amplamente utilizados em agropecuária como inseticidas, ocasionando intoxicações acidentais em animais e humanos, e mesmo sendo utilizados em tentativas de suicídio. A toxicidade desses produtos decorre sobretudo de insuficiência cárdio-respiratória por compromentimento do sistema nervoso autônomo. Sabe-se que alguns destes compostos induzem em animais de experimentação e em humanos, uma miopatia caracterizada por degeneração de células musculares, comprometendo sobretudo a musculatura respiratória. Baseado no fato de que este comprometimento contribui para a piora da função respiratória, propõe-se um protocolo de avaliação rotineira de miotoxicidade por compostos organofosforados, através de uma bateria mínima e suficiente de colorações e reações histoquímicas para quantificação da necrose muscular. Utilizaram-se como modelo experimental, grupos de ratos albinos (Wistar intoxicados com o organofosforado paraoxon, com e sem antídotos (atropina ou pralidoxima. Verificou-se nos grupos tratados com paraoxon e paraoxon mais atropina, necrose de fibras musculares no diafragma, que atingia em determinadas áreas até 15% das fibras. No grupo tratado com paraoxon mais pralidoxima, a necrose foi mínima, evidenciando o papel mioprotetor deste último antídoto.Organophosphates comprise a group of chemical compounds extensively used in farming as insecticides, which cause accidental poisoning in animals and men and are also used in suicide attempts. The toxicity of these compounds is due especially to the cardiac and respiratory impairment in consequence of autonomic nervous system disorders. However, it is known that some of these products induce a myopathy in experimental animals and humans. This myopathy is characterized by muscle cell degeneration, involving above all the respiratory muscles. Based on the fact that this involvement certainly enhances the

  12. Exercise training improves relaxation response and SOD-1 expression in aortic and mesenteric rings from high caloric diet-fed rats

    Directory of Open Access Journals (Sweden)

    Antunes Edson

    2008-05-01

    Full Text Available Abstract Background Obesity has been associated with a variety of disease such as type II diabetes mellitus, arterial hypertension and atherosclerosis. Evidences have shown that exercise training promotes beneficial effects on these disorders, but the underlying mechanisms are not fully understood. The aim of this study was to investigate whether physical preconditioning prevents the deleterious effect of high caloric diet in vascular reactivity of rat aortic and mesenteric rings. Methods Male Wistar rats were divided into sedentary (SD; trained (TR; sedentary diet (SDD and trained diet (TRD groups. Run training (RT was performed in sessions of 60 min, 5 days/week for 12 weeks (70–80% VO2max. Triglycerides, glucose, insulin and nitrite/nitrate concentrations (NOx- were measured. Concentration-response curves to acetylcholine (ACh and sodium nitroprusside (SNP were obtained. Expression of Cu/Zn superoxide dismutase (SOD-1 was assessed by Western blotting. Results High caloric diet increased triglycerides concentration (SDD: 216 ± 25 mg/dl and exercise training restored to the baseline value (TRD: 89 ± 9 mg/dl. Physical preconditioning significantly reduced insulin levels in both groups (TR: 0.54 ± 0.1 and TRD: 1.24 ± 0.3 ng/ml as compared to sedentary animals (SD: 0.87 ± 0.1 and SDD: 2.57 ± 0.3 ng/ml. On the other hand, glucose concentration was slightly increased by high caloric diet, and RT did not modify this parameter (SD: 126 ± 6; TR: 140 ± 8; SDD: 156 ± 8 and TRD 153 ± 9 mg/dl. Neither high caloric diet nor RT modified NOx- levels (SD: 27 ± 4; TR: 28 ± 6; SDD: 27 ± 3 and TRD: 30 ± 2 μM. Functional assays showed that high caloric diet impaired the relaxing response to ACh in mesenteric (about 13%, but not in aortic rings. RT improved the relaxing responses to ACh either in aortic (28%, for TR and 16%, to TRD groups or mesenteric rings (10%, for TR and 17%, to TRD groups that was accompanied by up-regulation of SOD-1

  13. Herida precordial por arma blanca

    Directory of Open Access Journals (Sweden)

    Marcelo F. Jiménez

    2005-04-01

    Full Text Available Varón de 42 años con esquizofrenia paranoide. Intento de suicidio con tres autolesiones por arma blanca (Fig. 1. Fue traído al hospital en estado consciente, taquicárdico, taquipneico y con tensión arterial (TA de 140/90 mmHg. Fue trasladado al quirófano, donde se practicó una toracotomía axilar izquierda sin extraer el arma. Durante la intervención se apreciaron tres heridas incisas, dos no penetrantes, hemotórax de 150 ml, herida pericárdica de 4 cm, sin lesiones cardíacas. La hoja del arma blanca penetraba a través del diafragma produciendo una herida incisa en el lóbulo hepático izquierdo (Fig. 2. Se extrajo el arma y se suturó la laceración hepática. El paciente fue trasladado el cuarto día a la Unidad de Psiquiatría.

  14. por láser

    Directory of Open Access Journals (Sweden)

    Mayra Garcimuño

    2013-01-01

    Full Text Available En el presente trabajo, la técnica Espectroscopia de plasmas producidos por láser (Laser-induced breakdown spectroscopy –LIBS– se aplicó a la determinación cuan- titativa de Na en agua natural dulce, de interés en agricultura para el estudio de la alcalinidad de aguas de regadío. Para efectuar el análisis, se prepararon soluciones con concentraciones conocidas del analito, se mezclaron con óxido de calcio y se compactaron en pastillas sólidas. Los plasmas se produjeron en aire a presión atmos- férica utilizando un láser pulsado Nd:YAG. Se construyó una curva de calibración y se calculó el límite de detección. Se analizaron muestras de agua natural y los resultados se compararon con los obtenidos mediante espectroscopia de absorción atómica. Se demostró la factibilidad del método para la determinación de Na en agua natural dulce.

  15. Targeting tumor-initiating cells: Eliminating anabolic cancer stem cells with inhibitors of protein synthesis or by mimicking caloric restriction

    Science.gov (United States)

    Lamb, Rebecca; Harrison, Hannah; Smith, Duncan L.; Townsend, Paul A.; Jackson, Thomas; Ozsvari, Bela; Martinez-Outschoorn, Ubaldo E.; Pestell, Richard G.; Howell, Anthony; Lisanti, Michael P.; Sotgia, Federica

    2015-01-01

    We have used an unbiased proteomic profiling strategy to identify new potential therapeutic targets in tumor-initiating cells (TICs), a.k.a., cancer stem cells (CSCs). Towards this end, the proteomes of mammospheres from two breast cancer cell lines were directly compared to attached monolayer cells. This allowed us to identify proteins that were highly over-expressed in CSCs and/or progenitor cells. We focused on ribosomal proteins and protein folding chaperones, since they were markedly over-expressed in mammospheres. Overall, we identified >80 molecules specifically associated with protein synthesis that were commonly upregulated in mammospheres. Most of these proteins were also transcriptionally upregulated in human breast cancer cells in vivo, providing evidence for their potential clinical relevance. As such, increased mRNA translation could provide a novel mechanism for enhancing the proliferative clonal expansion of TICs. The proteomic findings were functionally validated using known inhibitors of protein synthesis, via three independent approaches. For example, puromycin (which mimics the structure of tRNAs and competitively inhibits protein synthesis) preferentially targeted CSCs in both mammospheres and monolayer cultures, and was ~10-fold more potent for eradicating TICs, than “bulk” cancer cells. In addition, rapamycin, which inhibits mTOR and hence protein synthesis, was very effective at reducing mammosphere formation, at nanomolar concentrations. Finally, mammosphere formation was also markedly inhibited by methionine restriction, which mimics the positive effects of caloric restriction in cultured cells. Remarkably, mammosphere formation was >18-fold more sensitive to methionine restriction and replacement, as directly compared to monolayer cell proliferation. Methionine is absolutely required for protein synthesis, since every protein sequence starts with a methionine residue. Thus, the proliferation and survival of CSCs is very sensitive to

  16. Cardiac Sirt1 mediates the cardioprotective effect of caloric restriction by suppressing local complement system activation after ischemia-reperfusion.

    Science.gov (United States)

    Yamamoto, Tsunehisa; Tamaki, Kayoko; Shirakawa, Kohsuke; Ito, Kentaro; Yan, Xiaoxiang; Katsumata, Yoshinori; Anzai, Atsushi; Matsuhashi, Tomohiro; Endo, Jin; Inaba, Takaaki; Tsubota, Kazuo; Sano, Motoaki; Fukuda, Keiichi; Shinmura, Ken

    2016-04-15

    Caloric restriction (CR) confers cardioprotection against ischemia-reperfusion (I/R) injury. We previously found the essential roles of endothelial nitric oxide synthase in the development of CR-induced cardioprotection and Sirt1 activation during CR (Shinmura K, Tamaki K, Ito K, Yan X, Yamamoto T, Katsumata Y, Matsuhashi T, Sano M, Fukuda K, Suematsu M, Ishii I. Indispensable role of endothelial nitric oxide synthase in caloric restriction-induced cardioprotection against ischemia-reperfusion injury.Am J Physiol Heart Circ Physiol 308: H894-H903, 2015). However, the exact mechanism by which Sirt1 in cardiomyocytes mediates the cardioprotective effect of CR remains undetermined. We subjected cardiomyocyte-specific Sirt1 knockout (CM-Sirt1(-/-)) mice and the corresponding control mice to either 3-mo ad libitum feeding or CR (-40%). Isolated perfused hearts were subjected to 25-min global ischemia, followed by 60-min reperfusion. The recovery of left ventricle function after I/R was improved, and total lactate dehydrogenase release into the perfusate during reperfusion was attenuated in the control mice treated with CR, but a similar cardioprotective effect of CR was not observed in the CM-Sirt1(-/-)mice. The expression levels of cardiac complement component 3 (C3) at baseline and the accumulation of C3 and its fragments in the ischemia-reperfused myocardium were attenuated by CR in the control mice, but not in the CM-Sirt1(-/-)mice. Resveratrol treatment also attenuated the expression levels of C3 protein in cultured neonatal rat ventricular cardiomyocytes. Moreover, the degree of myocardial I/R injury in conventional C3 knockout (C3(-/-)) mice treated with CR was similar to that in the ad libitum-fed C3(-/-)mice, although the expression levels of Sirt1 were enhanced by CR. These results demonstrate that cardiac Sirt1 plays an essential role in CR-induced cardioprotection against I/R injury by suppressing cardiac C3 expression. This is the first report suggesting

  17. O estudo da prova calórica em pacientes idoso The study of caloric testing in senior patients

    Directory of Open Access Journals (Sweden)

    Débora Cristina de Oliveira Bezerra

    2008-01-01

    Full Text Available OBJETIVO: realizar o estudo da prova calórica em pacientes idosos com queixa de tontura, acompanhada ou não de zumbido com finalidade de traçar um perfil dos idosos quanto os sintomas vestibulares. MÉTODOS: fizeram parte da amostra 143 pacientes, com faixa etária variando de 60 a 90 anos de idade; todos realizaram o exame otoneurológico. Foram excluídos pacientes idosos com queixa de desequilíbrio e aqueles que apresentaram a queixa de zumbido desacompanhado da tontura. RESULTADOS: o estudo demonstrou que a normorreflexia, em valores absolutos, encontra-se entre 82,3% a 91,2% e os valores relativos são de 93%. Referente aos dados colhidos na anamnese, o que chamou a atenção, foi que do total de pacientes analisados, encontrou-se a tontura acompanhada de zumbido em 69% dos casos e o elevado uso de medicação em pacientes nesta faixa etária. CONCLUSÃO: na população estudada houve um predomínio da tontura acompanhada de zumbido. Em relação à prova calórica, o trabalho demonstrou a alta prevalência de pacientes com valores absolutos e relativos normais.PURPOSE: to accomplish the study of caloric testing in senior patients with dizziness, accompanied or not of with buzzing. METHODS: 143 patients were analyzed with age varying from 60 to 90 years; all of them did an otoneurologic evaluation. Senior patients with unbalance complaints and with buzzing unaccompanied with dizziness were excluded from this study. RESULTS: 82.3% to 91.2% of the patients obtained normoreflexia in absolute values and over 93% obtained normal results in relative values. Referring to the data obtained in the anamnesis, what got attention was 69% of dizziness accompanied with buzzing. And the high medication of the patients in this age group. CONCLUSION: there was a prevalence of dizziness accompanied with buzzing in the studied population. Concerning the caloric testing, the study demonstrated the high prevalence of patients with normal absolute and

  18. Fasting during Ramadan and Associated Changes in Glycaemia, Caloric Intake and Body Composition with Gender Differences in Singapore.

    Science.gov (United States)

    Yeoh, Ester C K; Zainudin, Sueziani Binte; Loh, Win Nie; Chua, Chin Lian; Fun, Sharon; Subramaniam, Tavintharan; Sum, Chee Fang; Lim, Su Chi

    2015-06-01

    Millions of Muslim patients with diabetes mellitus (DM) fast during Ramadan. However, little is known about the metabolic impact of Ramadan fasting. We aimed to study the changes in body composition and metabolic profile in this group of patients. We studied 29 Southeast Asian Muslim patients with type 2 diabetes; all underwent pre-Ramadan education. Study variables were weight change, body composition (using multifrequency bioimpedance method, InBody S20®, Biospace, South Korea), blood pressure (BP), glycated haemoglobin (HbA1c), fasting lipid profile, and caloric intake assessment using FoodWorks® nutrient analysis software. Twenty-three subjects fasted ≥15 days; mean ± SD: 57 ± 11 years; 52% were males. HbA1c improved significantly (8.6 ± 2.4% pre-Ramadan vs 8.0 ± 2.3% end-Ramadan, P = 0.017). Despite similar body weight, there was reduction in body fat mass (BFM) (30.9 ± 11 kg vs 29.2 ± 12.2 kg, P = 0.013). Multivariate analysis suggested that the reduction in HbA1c was attributed by reduction in BFM (β = -0.196, P = 0.034). There was no change in visceral adiposity (visceral fat area (VFA)) but stratification by gender showed a reduction amongst females (137.6 ± 24.5 cm2 to 132.5 ± 25.7 cm2, P = 0.017). These changes occurred despite similar total caloric intake (1473.9 ± 565.4 kcal vs 1473.1 ± 460.4 kcal, P = 0.995), and proportion of carbohydrate (55.4 ± 6.3% vs 53.3 ± 7.5%, P = 0.25) and protein intake (17.6 ± 4.1% vs 17.3 ± 5.4%, P = 0.792), before and during Ramadan respectively, but with increased proportion of fat intake (11.9 ± 2.4% vs 13 ± 11.7%, P = 0.04). Seven out of 23 patients had medications adjusted to avert symptomatic hypoglycaemia but none of the patients developed severe hypoglycaemia. Ramadan fasting can be practiced safely with prior patient education and medication adjustment. It also confers modest benefits on metabolic profile and body composition, especially among females.

  19. Osteomalacia inducida por tumor: hemangiopericitoma rinosinusal

    Directory of Open Access Journals (Sweden)

    Enriqueta M. Serafini

    2013-02-01

    Full Text Available La osteomalacia inducida por tumor es una rara enfermedad del metabolismo óseo caracterizada por el aumento en la excreción de fosfato a nivel renal seguido de hipofosfatemia. Es causada por agentes fosfatúricos producidos por determinados tumores. La resección total del tumor resulta en la completa reversión de las anormalidades bioquímicas, la desaparición de las manifestaciones clínicas y los hallazgos en los estudios por imágenes. Presentamos el caso de un varón de 61 años con cuadro clínico y laboratorio compatibles con osteomalacia oncogénica inducida por tumor mesenquimático de localización rinosinusal. En nuestro caso el diagnóstico histológico correspondió a una neoplasia de tipo vascular: hemangiopericitoma.

  20. 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-