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Sample records for empleando variables vinculadas

  1. Fases y variables vinculadas a la desindustrialización: un análisis en dos escalas territoriales

    Directory of Open Access Journals (Sweden)

    Jaime Sobrino

    2012-01-01

    Full Text Available En los estudios sobre economía espacial y economía industrial suele afirmarse que la desindustrialización consiste en la pérdida de importancia de la industria manufacturera en el mercado de trabajo y en la estructura económica. Los factores asociados a dicha pérdida se dividen entre los vinculados con la integración vertical de los servicios de orden superior al proceso productivo, y los relacionados con la falta de competitividad para la producción de bienes. El propósito de este artículo consiste en aportar elementos conceptuales y evidencia empírica para caracterizar la desindustrialización como un proceso que atraviesa por diversas fases, que van desde el crecimiento industrial hasta la pérdida absoluta de empleo y producción; asimismo busca explorar variables asociadas a tal proceso. Para ello se utilizan los instrumentos estadísticos de análisis de correspondencias, los modelos log-lineales y las funciones de regresión logística. En una primera etapa el estudio incluye 88 países, y en la segunda se cambia la escala geográfica para enfocarse en las 90 áreas urbanas y metropolitanas más pobladas de México. Se concluye que la desindustrialización en ambas escalas territoriales (país y ciudad comparte elementos comunes relacionados con un menor crecimiento económico y un mayor peso de los servicios al productor. Pero también se observan especificidades, como la mayor velocidad y variabilidad del proceso en las ciudades respecto a los países. La desindustrialización debe ser vista como un proceso, aunque no siempre lineal ni tampoco circunscrito a las naciones más desarrolladas o a las ciudades de mayor tamaño.

  2. Tasa diaria de evapotranspiración para una macrófita empleando variables meteorológicas

    OpenAIRE

    Scuderi, Carlos Marcelo; Villanueva, Adolfo; da Motta Marques, David

    2011-01-01

    La evapotranspiración (ET) es, generalmente, la principal variable de salida del ciclo hidrológico; siendo de importancia su cuantificación para el gerenciamiento del recurso hídrico. En este trabajo se presenta una metodología para estimar indirectamente la tasa diaria de ET de una macrófita bajo condiciones de clima templado húmedo. Paralelamente, se implementó un experimento con tanques enterrados donde se obtuvo una tasa de ET media diaria de 5.2 mm día-1. Dado que la tasa de ET es funció...

  3. VARIABLES TIC VINCULADAS A LA GENERACIÓN DE NUEVOS ESCENARIOS DE APRENDIZAJE EN LA ENSEÑANZA UNIVERSITARIA. APORTES DE LAS CURVAS ROC PARA EL ANÁLISIS DE DIFERENCIAS.

    OpenAIRE

    Ana García-Valcárcel Muñoz-Repiso; Francisco Javier Tejedor Tejedor

    2011-01-01

    Introducción: Los escenarios de aprendizaje se refieren a la descripción de las condiciones en las que se desarrolla la actividad formativa. La incorporación de las nuevas tecnologías a las aulas está generando nuevos escenarios de aprendizaje. Los objetivos del estudio son: 1) Análisis de variables contextuales y personales implicadas en el proceso de incorporación de las TIC en la enseñanza universitaria y sus consecuencias en los niveles de calidad (satisfacción y mejora en los indicado...

  4. Redefinición de competencias vinculadas a la productividad

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    José María Romero Rodríguez

    2016-08-01

    Full Text Available La formación por competencias ha adquirido un papel relevante en las últimas décadas. Entre otros aspectos de este enfoque, se han relacionado con la productividad en las empresas. En este momento, es pertinente una revisión de aquellas competencias transversales que pueden vincularse con la productividad y que pueden abrir nuevas perspectivas de estudio de este campo. Este artículo es el resultado de una revisión de la literatura existente sobre competencias profesionales y productividad empresarial en las bases de datos ProQuest, ERIC, ISOC y Dialnet. Mediante la confrontación de tres listados distintos de competencias obtenidos en la revisión de la literatura, se ha generado un único listado con 25 competencias transversales y la definición de las mismas, para su aplicación en futuras investigaciones, gestión del personal en las organizaciones y el posible establecimiento de planes formativos para transmitir aquellas competencias productivas. Los resultados de la revisión bibliográfica realizada posibilitan nuevas aproximaciones a la identificación de competencias, ofreciendo un listado actualizado de las competencias transversales vinculadas a la productividad que coinciden con las aportadas en otras investigaciones realizadas sobre competencias predictivas de un rendimiento eficaz, competencias para la empleabilidad y competencias en Formación Profesional del área de Servicios Socioculturales y a la Comunidad.

  5. El nuevo régimen de las operaciones vinculadas

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    Pedro Rosón Silván

    2011-06-01

    Full Text Available El nuevo y polémico régimen fiscal de operaciones vinculadas supone un cambio radical respecto de la regulación anterior a la Ley de Prevención del Fraude Fiscal de 2006, y pretende aproximar la normativa fiscal a los criterios expresados por las directrices de la OCDE sobre precios de transferencia, y a la nueva normativa contable, que se inspira en las Normas Internacionales de Contabilidad asumidas por la Unión Europea. Los principales cambios han afectado no solo al concepto de partes vinculadas (que se ha ampliado o la incorporación de los métodos de valoración de la OCDE, sino, sobre todo a: 1.La creación de una nueva obligación de documentación a cargo del obligado tributario que tiene que valorar sus operaciones a valor de mercado; 2.La creación de dos nuevas infracciones tributarias, para asegurar el cumplimiento de la obligación de documentación; 3.La simplificación del procedimiento de comprobación del valor normal de mercado; 4.La regulación expresa del denominado ajuste secundario. Pese a su novedad y por las presiones de los afectados, se han producido reformas para rebajar tanto las obligaciones de documentación como las sanciones, y, todo hace pensar que dado el contexto de crisis económica, puedan producirse más. The new and polemic fiscal regime of linked operations a radical change supposes respect of the regulation previous to the Law of Prevention of the Tax evasion of 2006, and tries to bring the fiscal regulation near to the criteria expressed by the directives of the OECD on prices of transfer, and to the new countable regulation, which inspires by the International Procedure of Accounting assumed by the European Union. The principal changes have concerned not only the concept of parts linked (that has been extended or the incorporation of the methods of valuation of the OECD, but, especially to: 1.The creation of a new obligation of documentation at the expense of the obliged tributary who has to

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

    Directory of Open Access Journals (Sweden)

    Lucas A. D´Addona

    2016-03-01

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

  7. Electrodeposition of nickel onto steel, using a thermostatic cell and movable anode by a variable current.; Electrodeposicion de niquel sobre acero al carbon, empleando una celda termostatizada y un anodo movil, por medio de una corriente pulsada rectangular.

    Energy Technology Data Exchange (ETDEWEB)

    Vega G, J D

    1994-12-31

    In this work, metallic coatings of nickel was made over carbon steel using two different electrolytic solutions: The Watts`s bath and the nickel sulfamate bath, using a pulse variable current. The method use was the traditional method, its means a thermostatic cell and one movable anode, which is a few know technique nowadays, it allow realize depositions away from any laboratory or special workshop, it has the advantage to be a portable dispositive. At last of all the electro depositions the coatings quality was valuable by them physical properties like: adhesion, hardness, wrinkled and thickness. The best results was obtain by the Nickel sulfamate bath and movable anode, less in the thickness, which has higher on the thermostatic cell. The variable current was obtain by a Pulse Generator and a Cathodic galvanometer. (Author).

  8. Biosorción de metales pesados empleando lodos activados

    OpenAIRE

    Santos Bonilla, Karín Ángela; Santos Bonilla, Karín Ángela

    2010-01-01

    Aunque las tecnologías existentes, tales como: precipitación química, osmosis inversa, intercambio iónico y separación por membranas representan una alternativa potencial para el tratamiento de drenajes ácidos de mina, presentan significativas desventajas como requerimientos altos de reactivos y energía; además de la generación de lodos tóxicos y otros subproductos a disponer. En este contexto, la biosorción empleando lodos activados procedentes de una planta de tratamiento de aguas residuale...

  9. Estrategias vinculadas a la atención de los estudiantes universitarios con discapacidad

    Directory of Open Access Journals (Sweden)

    Elaineth Abasali

    2018-01-01

    Full Text Available El objetivo de este estudio fue desarrollar estrategias instruccionales vinculadas a la atención de estudiantes universitarios con discapacidad, pertenecientes a la UPEL-IPC. La metodología estuvo constituida por un proyecto factible, con investigación de campo, documental y no experimental, se abordó el Modelo General de Desarrollo Tecnológico (MGDT de Szczurek (1990, el cual está constituido por cuatro fases: Estudio de Necesidades, Diseño de la Solución, Implantación y Evaluación. Los sujetos de investigación fueron  16 estudiantes con discapacidad, y 19 profesores del Departamento de Tecnología Educativa del IPC. En la implantación se ejecutó el diseño de la solución, obteniéndose resultados favorables, y posteriormente se procedió a la evaluación de todas las fases.

  10. Producción potencial de biogás empleando excretas de ganado porcino en el estado de Guanajuato

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    Miguel Martínez Lozano

    2015-01-01

    Full Text Available La actual reforma energética, así como los cambios mundiales en el uso y obtención de energía eléctrica o calorífica, empleando fuentes alternas, han llevado a replantear y maximizar el uso y explotación del biogás que se obtiene a partir de las excretas de diferentes tipos de ganado. El Estado de Guanajuato, posee un interesante número de cabezas de ganado en el ámbito bovino y porcino, lo que ha originado el planteamiento del presente artículo. En este trabajo, se presenta un estudio, empleando estadísticas locales, conducente a evaluar el potencial energético disponible a partir del uso de las excretas de ganado porcino, para producir Biogás y de ahí, establecer una valoración de la energía eléctrica anual obtenible, el ahorro en equivalente a barriles de petróleo que se podría manejar y la cantidad de gases que se dejarían de añadir a la atmósfera. El estudio se realiza dividiendo el estado por municipios y estableciendo los totales de cada variable de interés en el proceso. Los indicadores muestran que dada la sencillez de implementación de biodigestores para la producción de biogás, esta debe ser una alternativa interesante e importante a desarrollar y potenciar en los próximos años en el país. En el caso particular del Estado de Guanajuato, existen cerca de un millón de cerdos de diferentes edades registrados, pudiendo producir una energía potencial para alimentar a más de 60,000 viviendas estándar.

  11. Estudio del abandono empleando un modelo de riesgos proporcionales

    OpenAIRE

    Gonzalez, Mariana Verónica

    2017-01-01

    En este trabajo se aplica  un modelo de riesgo semi-paramétrico para identificar algunas variables que contribuyen a explicar el fenómeno del abandono estudiantil en una unidad académica de la Universidad Nacional de Córdoba (UNC), Argentina. La inactividad académica prolongada se toma como proxy de la variable dependiente. Los resultados muestran que el promedio del secundario aparece como importante predictor de la deserción. Además, se detectó que los estudiantes que costean sus estudios c...

  12. Asesinatos empleando relajantes musculares, opioides y otras drogas anestésicas

    OpenAIRE

    Martínez Hurtado, Eugenio; Gómez García, Ana María

    2012-01-01

    Los anestésicos, los opiáceos y los relajantes musculares pueden deprimir la respiración y otros procesos vitales hasta el extremo de producir la muerte si no se mantiene la ventilación. De modo que estos fármacos se han empleado para la eutanasia, el suicidio y las ejecuciones. Los criminales también han reparado en las posibilidades letales de los anestésicos, y durante los años recientes se han cometido homicidios empleando hipnóticos, anestésicos generales inhalados, opiáceos y relajantes...

  13. Deporte Salud y Vida para oyentes de radio Familia 96.9 empleando pausa activa

    OpenAIRE

    Martínez Sarmiento, Marcia Fabiola

    2011-01-01

    Deporte Salud y Vida para oyentes de radio Familia 96.9 empleando pausa activa, un programa de radio que promueve a la práctica de actividad física, que permita contrarrestar las grandes escalas de sedentarismo en nuestra ciudad, gracias al apoyo de este medio de comunicación se implementó la Pausa activa para oyentes de Radio Familia, especialmente amas de casa que fluctúan desde los 20 hasta 75 años. El proyecto tiene también el objetivo de la ejercitación mediante la Pausa Activa dentro...

  14. Flujo de carga con armónicos empleando la matriz impedancia de barras

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    José A González Quintero

    2011-03-01

    Full Text Available Se describe un flujo de armónicos empleando la matriz impedancia de barras. El algoritmo propuesto permite hallar losvoltajes de cada nodo del circuito sin tener que realizar la solución simultánea de todas las ecuaciones no linealescorrespondientes a cada nodo, ni siquiera la solución simultánea de las ecuaciones correspondientes a una redreducida de nodos no lineales solamente.  This work describes a harmonic load flow using the bar impedance matrix. The proposed algorithm permit to findevery node voltage of the circuit without to realize the simultaneous solution of all the non-linear equationscorresponding to each node, not even the simultaneous solution of the equations corresponding to a reducednetwork of only non-linear nodes.

  15. Aptitud física en mujeres adultas mayores vinculadas a un programa de envejecimiento activo Physical fitness in older woman related to an active aging program

    Directory of Open Access Journals (Sweden)

    Jorge Enrique Correa Bautista

    2011-12-01

    Full Text Available Objetivo: Determinar la aptitud física, entendida como la capacidad para desarrollar actividades normales de la vida diaria de forma segura, con independencia y sin excesiva fatiga, en un grupo de mujeres, vinculadas durante ocho meses al programa de recreación para el adulto mayor del Instituto Distrital de Recreación y Deporte (IDRD, de la localidad de Puente Aranda de la ciudad de Bogotá. Materiales y métodos: Estudio transversal de una cohorte de n= 344 mujeres en edades entre 60 y 87 años, a las cuales se les realizaron mediciones de peso (Kg, talla (cm, porcentaje de grasa, perímetro de cintura (cm, fuerza muscular de resistencia en miembros inferiores, y resistencia aeróbica, de acuerdo a la Bateria Senior Fitness Test (SFT.La agilidad no fue tenida encuenta. Para identificar el cambio de comportamiento de la población se utilizó el modelo transteórico de Prochaska y Velicer Resultados: El (56,4 % de las mujeres del estudio se encontró en etapa de acción en relación al comportamiento frente a la actividad física. Se identificaron 159 mujeres en sobrepeso, 121 mujeres con fuerza de resistencia adecuada, 183 con resistencia aeróbica dentro de los parámetros de normalidad y 183 mujeres con mala flexibilidad. Conclusión: A partir de los resultados descritos concluimos que la práctica regular de actividad física en la población de mujeres personas mayores trajo beneficios, pues su nivel de aptitud física sobre todo en lo relacionado con la fuerza en miembros inferiores y la capacidad aeróbica, mostró niveles suficientes y se clasificaron como activas físicamente. Salud UIS 2011; 43 (3: 263-269Objective: To determine physical fitness, understood as ability to develop normal activities of daily living safely, independently and without excessive fatigue through the measurement of physical components as the force of resistance, endurance, and agility in a group of women, linked for 8 months in a recreation program for the

  16. Síntesis de copolímeros de PS-b-PMMA empleando polimerización radicalaria controlada

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    Vivina Hanazumi

    2016-01-01

    Full Text Available Se estudió la síntesis de copolímeros bloque de poli (estireno y poli (metil metacrilato (PS-b-PMMA empleando polimerización radicalaria por transferencia atómica (ATRP. Se realizaron distintos experimentos variando las relaciones molares de monómero, ligando e iniciador para determinar su influencia en la síntesis de copolímeros PS-b-PMMA con masas molares determinadas y estructura homogénea. Los polímeros sintetizados se caracterizaron químicamente por espectroscopia infrarroja con Transformada de Fourier (FTIR y cromatografía por exclusión de tamaños (SEC, empleando un detector de índice de refracción. Se obtuvieron los copolímeros bloque propuestos, con un buen control de su estructura macromolecular (Mw/Mn < 1,90.

  17. Estructura Organizacional de las Empresas Vinculadas a la Incubadora de Base Tecnológica de la Universidad de Fortaleza: Un Análisis Bajo la Perspectiva de Mintzberg.

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    Sarah Mesquita Lima

    2014-09-01

    Full Text Available El presente estudio tiene el objetivo principal de analizar si la configuración estructural predominante de las empresas asociadas a la Incubadora de Base Tecnológica de la Universidad de Fortaleza está vinculada a sus competencias. Para alcanzar el objetivo propuesto se realizó una investigación descriptiva y cualitativa, con estudio de múltiples casos. Los datos fueron recolectados mediante el análisis de documentos, entrevista con el coordinador del Espacio de Desarrollo de Empresas de Tecnología (EDETEC de la UNIFOR y aplicación de cuestionarios auto-administrados en las empresas vinculadas al EDETEC/UNIFOR. Los resultados indicaron el predominio de las configuraciones Burocracia Profesional, Estructura Simple y Adhocracia, estando estas dos últimas directamente vinculadas a las competencias emprendedoras e innovadoras.

  18. Cálculo de la distribución espacial de la insolación potencial en el terreno empleando MDE en un ambiente SIG

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    Alberto Gómez Tagle Chávez

    2012-02-01

    Full Text Available Se presenta un estudio de caso donde se calcula la insolación potencial (IP y la insolación real (IR para un área pequeña (634.4 ha empleando los programas Insol_Día e Insol_Mes a partir de un modelo digital de elevaciones (MDE. Estos programas calculan la IP utilizando la ubicación geográfica de la cuenca y el MDE mediante procedimientos de sistemas de información geográfica (SIG y ecuaciones de geometría esférica. La IR se obtuvo empleando los mapas digitales de IP calculada y corrigiendo los datos con información del observatorio meteorológico (15-0040, Morelia, Mich. del Servicio Meteorológico Nacional. Los resultados son una serie de mapas digitales dentro de un SIG que permiten conocer la distribución espacial de la IP y la IR en esta zona, para fechas definidas, meses enteros, estaciones y totales anuales. La IP anual máxima fue de 4 389 horas, mientras que la mínima fue de 2 946 horas. Los valores de IR máxima y mínima fueron 2 144.9 y 1 439.7 horas. Los promedios diarios anuales de IP máximo y mínimo fueron de 12.05 hr/día y 8.07 hr/día, siendo para IR de 5.88 hr/día y 3.944 hr/día, indicando una gran diferencia entre la IP y la IR. Se considera que este tipo de información puede ser de gran utilidad en estudios de distribución de la vegetación, balances hidrológicos, distribución de propiedades edáficas, velocidad de intemperismo de los materiales geológicos, arquitectura bioclimática y otras áreas donde la distribución espacial de la insolación se considere como una variable importante.

  19. Teoría de la mente en un grupo de personas vinculadas al conflicto armado y en proceso de resocialización

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    Mónica Gómez

    2013-12-01

    Full Text Available La teoría de la mente es la capacidad de inferir, predecir y atribuir estados mentales a otras personas. Este constructo ha sido estudiado desde numerosas patologías, como el autismo, la esquizofrenia y el síndrome de down. Estudios recientes han mostrado que las alteraciones de la teoría de la mente pueden ser observadas en los diferentes cuadros clínicos derivados de alteraciones del lóbulo frontal, como la personalidad antisocial. Algunos autores plantean que un aspecto esencial de la teoría de la mente es la empatía. Sin embargo, este constructo no ha sido estudiado en población normal colombiana con conductas violentas y delictivas que han estado vinculadas al conflicto armado. Este artículo tiene como propósito describir algunas características de la tom en sujetos que estuvieron vinculados al conflicto armado en antioquia con manifestaciones sintomáticas relacionadas con comportamientos violentos y delictivos.

  20. Proyecto de mejora de la durabilidad de los pavimentos usados en aeropuertos empleando materiales alternativos y geo-sintéticos

    OpenAIRE

    Cabezuelo Moreno, Juan José

    2015-01-01

    Contribuir a la mejora de la durabilidad de los pavimentos usados en las pistas de aeropuertos, en particular pavimentos de tipo flexible, empleando combinaciones de capas de diferentes materiales y geo-sintéticos. En particular, plantear el uso de materiales novedosos como alternativa a las típicas capas de pavimento a base de hormigón y mejora de la durabilidad de las mismas empleando combinaciones de sendos materiales y geo-sintéticos. El mundo de la aviación y en concreto el del diseño...

  1. Registro de actividad eléctrica en la retina de una rata albina empleando una matriz de microelectrodos

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    Edwin Alexander Cerquera

    2015-09-01

    Full Text Available Las matrices de microelectrodos son dispositivos que permiten la detección de potenciales de acción o espigas en poblaciones de células excitables, ofreciendo varias aplicaciones en el campo de las neurociencias y la biología. Este trabajo muestra un protocolo para el registro de espigas en una población de células ganglionares retinales empleando una matriz de microelectrodos. La retina de una rata albina fue extraída y preparada para ser estimulada in vitro con luz led blanca, con el fin de registrar sus espigas evocadas ante estos estímulos. Cada microelectrodo puede registrar espigas de más de una célula ganglionar, razón por la cual se determinó a qué célula pertenece cada espiga aplicando un procedimiento conocido como “clasificación de espigas”. El trabajo permitió obtener el registro de un periodo de estimulación y otro de no estimulación, con el fin de representar los potenciales de acción evocados con luz y los espontáneos. Los registros fueron almacenados para visualizar las espigas de las células ganglionares y poder aplicar la herramienta de clasificación de espigas. De este modo, se almacenan los instantes de tiempo en los cuales cada célula ganglionar registrada generó potenciales de acción. Este trabajo conllevó al establecimiento de un protocolo de experimentación básico enfocado al uso de matrices MEA en el laboratorio de adquisición de potenciales extracelulares de la Universidad Antonio Nariño Sede Bogotá, no sólo para caracterizar los potenciales de acción de células ganglionares retinales, sino también para otro tipo de células que puedan ser estudiadas empleando matrices de microelectrodos.

  2. Estrutura de referência para incubadoras pertencentes a redes de habitats de inovação tecnológica e vinculadas a instituições de ensino

    OpenAIRE

    Rasoto, Vanessa Ishikawa

    2006-01-01

    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. A partir do estudo de caso da REPARTE (Rede Paranaense de Incubadoras e Parques Tecnológicos), esta pesquisa construiu uma estrutura de referência de incubadoras pertencentes a redes de habitats de inovação tecnológica vinculadas às instituições de ensino superior (IES). O objetivo desta estrutura de referência é orientar o desenvolvimento de incubadoras atrav...

  3. Internet de los objetos empleando arduino para la gestión eléctrica domiciliaria

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    Adriana Marcela Vega E.

    2014-03-01

    Full Text Available Rev.esc.adm.neg El presente artículo muestra la importancia de la gestión eléctrica domiciliaria por medio del diseño, desarrollo e implementación de un prototipo de sistema domótico, que permite utilizar de manera remota una bombilla LED a través de las acciones de prender y apagar, según las necesidades del usuario, sin importar en donde se encuentre ubicado, es decir, que su localización geográfica no importa. Para su desarrollo se emplearon elementos de Hardware como el Arduino y de Software como los servicios en la nube de Windows Azure®; con esta aplicación, se pretende observar la interoperabilidad entre un dispositivo ubicado en el hogar y un servidor ubicado en el mundo virtual del Internet. Lo anterior permite hacer un acercamiento a las múltiples modalidades que se pueden desarrollar con el Internet de los objetos y que en un futuro próximo será empleando por las personas de manera permanente en sus residencias.

  4. Paralelización del Algoritmo Criptográfico GOST Empleando el Paradigma de Memoria Compartida

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    Marlis Fulgueira-Camilo

    2015-06-01

    Full Text Available El artículo refiere el proceso de paralelización del algoritmo criptográfico GOST. La investigación realizada persigue como objetivo, reducir el tiempo de ejecución del algoritmo. El estudio no se encuentra enfocado al análisis de fortaleza del algoritmo criptográfico, donde se hace énfasis es en el método empleado para disminuir el tiempo de ejecución de los procesos cifre y descifre. Para ello se realiza un diseño paralelo basado en la metodología de Ian Foster, el cual es aplicado a dos implementaciones usando técnicas como: OpenMP y CUDA. Las comparaciones realizadas teniendo en cuenta, tanto al algoritmo secuencial como las implementaciones paralelas, demuestran una significativa reducción de tiempo, sin importar la técnica empleada. El mejor resultado se logra empleando CUDA.

  5. Prevalência da infecção por HIV em parturientes de maternidades vinculadas ao SUS Prevalence of infection with in unified health care system maternities

    Directory of Open Access Journals (Sweden)

    Lígia Mara Dolce de Lemos

    2005-01-01

    Full Text Available OBJETIVO: avaliar a prevalência do HIV nas parturientes de maternidades vinculadas ao SUS, pela utilização do teste rápido. MÉTODOS: estudo transversal realizado em maternidades conveniadas ao SUS no Estado de Sergipe, após treinamento realizado com os profissionais de saúde dessas maternidades. As parturientes foram submetidas ao teste rápido imunocromatográfico para HIV, independente de já o terem realizado no pré-natal, após aconselhamento e assinatura do termo de consentimento livre e esclarecido. O teste utilizado foi DetermineTM - Abbott Laboratórios do Brasil. Utilizou-se o esquema de profilaxia da transmissão vertical para todos os casos, segundo o protocolo recomendado pelo Ministério da Saúde. Foi criado banco de dados no Epi-Info 2002 e calculada a prevalência em relação a todos os testes realizados no período de janeiro de 2003 a março de 2004, por meio de análise estatística descritiva. RESULTADO: após realização de 9.215 testes rápidos, foram detectadas 39 (0,42% soropositivas para HIV, das quais 23 (59% não conheciam a sua soropositividade. Duas gestantes que já eram sabidamente HIV positivas não relataram aos profissionais sua condição no momento da admissão. O número de parturientes que referiram ter freqüentado o serviço de pré-natal foi alto (89%, mas somente 32,5% destas foram submetidas ao teste para HIV na gestação. CONCLUSÃO: a prevalência detectada (0,42% neste estudo é semelhante à nacional. É alta a prevalência de parturientes que desconhecem sua soropositividade para HIV, o que indica inadequado funcionamento de cuidados pré-natais dispensados. Na situação atual é necessária a triagem no momento do parto, para garantia de intervenções adequadas neste momento crucial da transmissão do HIV.PURPOSE: to evaluate the prevalence of HIV infection in parturient women from maternity hospitals linked to the Public Health Service in Sergipe state (Brazil using the rapid test

  6. Diseño de Hardware y Software de Systems on Chip empleando tecnología Xilinx EDK

    Directory of Open Access Journals (Sweden)

    Julio Cadena

    2012-11-01

    Full Text Available El presente artículo resume el proceso empleado para obtener el primer System on Chip (SoC diseñado, desarrollado, y emulado en la Escuela Politécnica del Ejército (ESPE y en el Ecuador. Se demostrará que combinando las ventajas del diseño sobre Field Programable Gate Arrays (FPGAs empleando la reutilización de IP Cores y plataformas, junto al uso de la tecnología de desarrollo Xilinx EDK, se puede diseñar tanto el hardware como el software de un chip de manera rápida y económicamente fiable. Además, se detalla el uso de la metodología Platform Based Design (PBD y del concepto de co-diseño de hardware y software para diseñar las capas de hardware, sistema operativo y aplicación de un chip. La capa de hardware contiene una serie de IP Cores gobernados por un procesador MicroBlaze trabajando dentro de la arquitectura CoreConnect de IBM. Mientras que la capa de sistema operativo está conformada por drivers, librerías y el Sistema Operativo en Tiempo Real (RTOS Xilkernel. Por último, la capa de aplicación tiene la funcionalidad de controlar una planta de temperatura, mediante la selección de dos técnicas de control: ON-OFF o PID. Cabe destacar que el co-diseño se desarrolló considerando un adecuado enfoque conceptual, arquitectural, y metodológico1.

  7. La obtención y proyección de tablas de mortalidad empleando curvas. Spline

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    Alejandro MINA-VALDÉS

    2011-01-01

    Full Text Available Una de las herramientas del análisis numérico es el uso de polinomios de n-ésimo orden para interpolar entre n + 1 puntos, teniéndose casos en donde estas funciones polinómicas pueden llevar a resultados erróneos. Una alternativa es la de aplicar polinomios de orden inferior a subconjuntos de datos. Estos polinomios conectados se llaman funciones de interpolación segmentaria (spline functions. En este artículo se presenta la herramienta que el análisis numérico proporciona como instrumento técnico necesario para llevar a cabo todos los procedimientos matemáticos existentes con base a algoritmos que permitan su simulación o cálculo, en especial, las funciones splines definidas a trozos (por tramos, con interpolación mediante ellas, dando lugar a el ajuste de curvas spline con base en la serie de sobrevivientes lx de una tabla abreviada de mortalidad mexicana, con el fin de desagregarla por edad desplegada, respetando las concavidades que por el efecto de la mortalidad en las primeras edades y en las siguientes se tienen en la experiencia mexicana. También empleando las curvas splines se presentan las simulaciones que permiten obtener escenarios futuros de las series de sobrevivientes lx, que dan lugar a las proyecciones de la mortalidad mexicana para los años 2010-2050, las que generan las tablas completas de mortalidad para hombres y mujeres de dicho periodo, resaltando las diferencias entre sexos y edades de sus probabilidades de supervivencia y las ganancias en las esperanzas de vida.

  8. Cómo una microempresa logró un desarrollo de productos ágil y generador de valor empleando Lean

    OpenAIRE

    Barón Maldonado, Diana Isabel; Rivera Cadavid, Leonardo

    2014-01-01

    El propósito del presente artículo es mostrar un ejemplo de cómo una microempresa puede hacer que su desarrollo de productos sea más ágil, flexible y generador de valor empleando Lean. Se tomaron como referentes el proceso genérico de desarrollo de productos, el proceso de desarrollo tradicional en el sector de confecciones, el sistema Toyota de desarrollo de productos y el antiguo sistema de desarrollo de la empresa. Se destacan el rol del lugar de reunión virtual y el papel del ingeniero je...

  9. Evaluación de la calidad de los registros empleando la auditoría odontológica en una clínica dental docente

    OpenAIRE

    Manrique Guzmán, Jorge A.; Manrique Chávez, Jorge E.; Chávez Reátegui, Beatriz; Manrique Chávez, Carolina B.

    2014-01-01

    Objetivo: Evaluar la calidad de registro o llenado de historias clínicas de pacientes nuevos atendidos en unaClínica Dental Docente durante el período de enero a julio de 2012 empleando la auditoría odontológica comoherramienta sistematizada. Material y métodos: Se tomaron como muestra 140 historias clínicas de pacientesnuevos de las cuales se evaluó la frecuencia y porcentaje de registro de los diferentes aspectos que componenla historia clínica. Resultados: Se encontró que el 78% de las his...

  10. Comportamiento de vigas de sección compuesta con perfiles de acero laminado y losa de concreto empleando conectores de cortante tipo tornillo grado dos (2)

    OpenAIRE

    García Zamora, Alejandro; Molina Herrera, Maritzabel

    2008-01-01

    En el presente artículo, partiendo de un análisis teórico-experimental, se determinan y caracterizan los parámetros de diseño que rigen el comportamiento de las vigas compuestas de perfiles de acero y losa de concreto empleando conectores de cortante tipo tornillo, dado que para esta clase de conector no existe un estudio específico de su comportamiento, además en la actualidad su diseño no está definido en las NSR-98, aunque es uno de los tipos de conectores más empleados en la construcción ...

  11. Comportamiento de vigas de sección compuesta con perfiles de acero laminado y losa de concreto empleando conectores de cortante tipo tornillo grado dos (2)

    OpenAIRE

    García Zamora, Alejandro; Molina Herrera, Maritzabel

    2010-01-01

    En el presente artículo, partiendo de un análisis teórico-experimental, se determinan y caracterizan los parámetros de diseño que rigen el comportamiento de las vigas compuestas de perfiles de acero y losa de concreto empleando conectores de cortante tipo tornillo, dado que para esta clase de conector no existe un estudio específico de su comportamiento, además en la actualidad su diseño no está definido en las NSR-98, aunque es uno de los tipos de conectores más empleados en la construcción ...

  12. Procedimiento para elaborar una lente intraocular monofocal asférica isoplanática y lente obtenida empleando dicho procedimiento

    OpenAIRE

    Barbero, Sergio; Marcos, Susana; Dorronsoro, Carlos; Montejo, Javier; Salazar Salegui, Pedro

    2010-01-01

    Procedimiento para elaborar una lente intraocular monofocal asférica isoplanática y lente obtenida empleando dicho procedimiento. Permite obtener lentes oftálmicas monofocales asféricas isoplanáticas en un rango visual de hasta 25º (preferentemente hasta 10º) de amplitud. El procedimiento comprende las etapas de: 1.- Definición matemática de un modelo de ojo afáquico; 2.- Definición matemática de un modelo de lente intraocular; 3.- Definición matemática de la implantac...

  13. Consideraciones de diseño para la eliminación biológica de fósforo empleando procesos biopelícula

    OpenAIRE

    Castillo de Castro, Pedro; Tejero Monzón, Iñaki

    1999-01-01

    El siguiente artículo es un resumen del estado del arte de la Eliminación Biológica de Fósforo (EBF) empleando procesos de biopelícula. En él se describen minuciosamente los mecanismos que intervienen en la eliminación biológica de este elemento, así como las teorías actualmente aceptadas. Se presentan los procesos biopelícula actualmente desarrollados, así como los consideraciones de diseño para reactores biopelícula, y la forma de trabajo necesaria para conseguir la EBF.

  14. Reconocimiento automático de locutor a través de aprendizaje automático mediante redes neuronales empleando el paquete de software libre Kaldi

    OpenAIRE

    Jiménez Andreu, Rubén

    2017-01-01

    El objetivo del presente Proyecto Fin de Máster es presentar algunas técnicas para reconocimiento de hablante empleando redes neuronales y deep learning. Como referencia se emplean vectors y un modelo universal basado en mezclas gaussianas (GMM-UBM) como método del estado del arte. El proceso de entrenamiento es realizado con la base de datos de audiolibros LibriSpeech. Esta base también se emplea para evaluar los modelos, junto con la de Speakers in the Wild, con locucion...

  15. Cómo una microempresa logró un desarrollo de productos ágil y generador de valor empleando Lean

    OpenAIRE

    Barón Maldonado, Diana Isabel; Rivera Cadavid, Leonardo

    2014-01-01

    El propósito del presente artículo es mostrar un ejemplo de cómo una microempresa puede hacer que su desarrollo de productos sea más ágil, flexible y generador de valor empleando Lean. Se tomaron como referentes el proceso genérico de desarrollo de productos, el proceso de desarrollo tradicional en el sector de confecciones, el sistema Toyota de desarrollo de productos y el antiguo sistema de desarrollo de la empresa. Se destacan el rol del lugar de reunión virtual y el papel del ...

  16. Identidades, poder e incidencia política de organizaciones vinculadas a inmigrantes nicaragüenses en costa rica: aportes teóricos y metodológicos

    Directory of Open Access Journals (Sweden)

    Francisco Javier Mojica-Mendieta

    2007-10-01

    Full Text Available Propone desde un enfoque de investigación cualitativo, comprender la relación entre las representaciones sociales de las identidades nacionales y la incidencia de la política de distintas organizaciones vinculadas con inmigrantes nicaragüenses, con el fin de dar insumos tendientes a mejorar la calidad de vida de la población inmigrante en Costa Rica. Abstract The article proposes an approach from the qualitative research standpoint to understand the relationship between the social representations of the national identities and the political incidence of different political organization linked to Nicaraguan inmigrants as bases for the betterment of the inmigrant population in Costa Rica.

  17. Criterios para la selección de imágenes sin estereotipos vinculadas con la práctica de actividad físico-deportiva en la edición de libros de texto

    OpenAIRE

    Ana REY CAO; M.ª Inés Inés TÁBOAS PAIS; Alba GONZÁLEZ PALOMARES

    2014-01-01

    El artículo presenta criterios de evaluación para seleccionar las imágenes vinculadas con la práctica de actividad físico-deportiva en la edición de libros de texto de tal forma que estén libres de estereotipos. Los manuales escolares son portadores de un conocimiento que no siempre guarda una relación unívoca con lo que debe ser enseñado. La selección de sus contenidos debería ser coherente con las finalidades del sistema educativo, pero la investigación revela que la edición de los contenid...

  18. Criterios para la selección de imágenes sin estereotipos vinculadas con la práctica de actividad físico-deportiva en la edición de libros de texto

    Directory of Open Access Journals (Sweden)

    Ana REY CAO

    2014-10-01

    Full Text Available El artículo presenta criterios de evaluación para seleccionar las imágenes vinculadas con la práctica de actividad físico-deportiva en la edición de libros de texto de tal forma que estén libres de estereotipos. Los manuales escolares son portadores de un conocimiento que no siempre guarda una relación unívoca con lo que debe ser enseñado. La selección de sus contenidos debería ser coherente con las finalidades del sistema educativo, pero la investigación revela que la edición de los contenidos visuales no se corresponde con la aplicación de criterios que respondan a esa intencionalidad. Tras una aparente neutralidad, las imágenes de los libros de texto enmascaran prejuicios y reproducen desigualdades que afectan a determinados colectivos frágiles. Los criterios de evaluación para la selección de imágenes que se presentan en este trabajo fueron elaborados de acuerdo con los resultados de una investigación que analizó los estereotipos de género, edad, raza, discapacidad y tipología corporal en las imágenes de manuales escolares de educación física para la ESO en España, así como la percepción del alumnado de secundaria sobre una selección significativa de las mismas imágenes. Los criterios elaborados pueden aplicarse para la selección de fotografías destinadas a manuales de diferentes áreas de conocimiento en las que aparezcan representadas personas vinculadas a la práctica de actividad físico-deportiva. La aplicación de los criterios de evaluación se ejemplifica en la selección de contenidos visuales para un hipotético libro de educación física.

  19. Mejoramiento de la productividad de la línea de extrusión de la empresa CEDAL, empleando la metodología "Six Sigma"

    OpenAIRE

    Garcés Muñoz, Luis Alfredo

    2016-01-01

    El presente trabajo tuvo como objetivo el mejoramiento de la productividad del proceso de extrusión en la empresa CEDAL, empleando la metodología “Six Sigma”. Para esto, se analizó la situación actual del proceso de extrusión por medio de 4 indicadores claves de desempeño o KPI. Se concluyó, que el KPI que mide la cantidad de rechazos de material no conforme, obtuvo una mejora en la productividad después de la implementación de las fases DMAMC, al tener una línea base del indicador en el mes ...

  20. Deshidratación de etanol empleando líquidos iónicos de naturaleza prótica

    OpenAIRE

    Acosta Cordero, L.; Pérez Ones, O.; Zumalacárregui de Cárdenas, L.

    2017-01-01

    En este trabajo se presenta el estudio experimental de la deshidratación de etanol empleando líquidos iónicos de naturaleza prótica, con el objetivo de determinar un líquido iónico prótico efectivo en este proceso de separación. Para ello se sintetizaron tres líquidos iónicos (formiato de 2-hidroxietilamonio, lactato de2-hidroxietilamonio y propionato de 2-hidroxietilamonio) y se determinaron sus propiedades críticas y densidad apartir de métodos de contribución de grupos. Además se confirmó ...

  1. VARIABLES TIC VINCULADAS A LA GENERACIÓN DE NUEVOS ESCENARIOS DE APRENDIZAJE EN LA ENSEÑANZA UNIVERSITARIA. APORTES DE LAS CURVAS ROC PARA EL ANÁLISIS DE DIFERENCIAS.

    Directory of Open Access Journals (Sweden)

    Ana García-Valcárcel Muñoz-Repiso

    2011-01-01

    para su aprendizaje. Discusión: Los alumnos pueden reconocer diversos ¿escenarios¿ en la actuación de un profesor a lo largo de las clases de una determinada asignatura. Nos parece que este dato, que nos encontramos con notoria evidencia en nuestra investigación, debe interpretarse en términos positivos por reflejar una diversidad enriquecedora tanto en las finalidades que orientan su acción docente (reproductiva en algún caso, profesional, crítica y creativa en otros como, sobre todo, en la diversidad metodológica, que se concreta en la diversidad de recursos que el profesor utiliza y en la amplia gama de actividades que el profesor puede estar planteando a los alumnos. Diversidad de recursos y actividades, que van a posibilitarse en mayor medida con el uso de las TIC.

  2. Os procedimentos adotados pelos Tribunais de Contas da Bahia para a verificação das receitas e despesas vinculadas à educação Los procedimientos adoptados por los Tribunales de Cuentas del estado brasileño de Bahia para la verificación de ingresos y despesas vinculadas a la educación The procedures adopted by the Audit Courts of Bahia for checking revenue and expenses linked to education

    Directory of Open Access Journals (Sweden)

    Nicholas Davies

    2010-03-01

    Full Text Available O artigo examinou, com base em resoluções e/ou relatórios de contas, os procedimentos adotados pelos Tribunais de Contas do Estado (TCE e dos Municípios (TCM da Bahia para a verificação da receita e despesa vinculada à educação e constatou uma série de omissões, inconsistências e equívocos que muito provavelmente reduziram o montante de recursos legalmente vinculados à educação. O TCE, por exemplo, se limitou à contabilização do percentual mínimo dos impostos e nunca mencionou as receitas adicionais a este mínimo, como o salário-educação, os repasses federais para merenda e outros programas ou operações de crédito vinculadas à educação, significativas no caso da Bahia. Além disso, os relatórios contêm dados discrepantes e confundem gastos na função orçamentária Educação com os realizados em manutenção e desenvolvimento do ensino, dois conceitos diferentes. Também o TCM cometeu muitos equívocos, em suas resoluções, a começar pela terminologia. Empregou 'ensino básico' no lugar de 'educação infantil' e confundiu despesas no ensino (categoria mais ampla com despesas no Fundef (categoria mais restrita. Incorreu em ilegalidade ao aceitar que parte dos 40% dos recursos do Fundef (ou do Fundeb fossem destinados a escolas comunitárias, confessionais ou filantrópicas.El artículo ha examinado, con base en resoluciones y/o informes de cuentas, los procedimientos adoptados por los Tribunales de Cuentas de la Provincia (TCE y de los Municipios (TCM de Bahia para la verificación de los ingresos e despesas vinculadas a educación y ha constatado una serie de omisiones, inconsistencias y equívocos que muy probablemente han reducido el montante de fondos legalmente vinculados a la educación. El TCE, por ejemplo, ha limitado a la contabilización del porcentual mínimo de los impuestos y nunca mencionó los ingresos adicionales a este mínimo, como las transferencias federales para el gobierno provincial y

  3. Simulación de la destilación extractiva para la obtención de etanol anhidro empleando glicoles

    Directory of Open Access Journals (Sweden)

    Yeney Guerra Lauzurique

    2016-01-01

    Full Text Available Se evaluó la técnica de destilación extractiva empleando propilenglicol, etilenglicol, glicerol y una mezcla de etilenglicol y glicerol, por ser los solventes más empleados a nivel mundial. Para la simulación de las técnicas se utilizó el simulador de procesos hysys v3.2 y para su comparación se estableció un mismo flujo molar de etanol en la mezcla etanol-agua de 216,5 kmol/h. En todos los casos se obtuvo una composición molar de etanol anhidro mayor de 97 %. Se determinó la influencia de los parámetros de operación en la eficiencia de las tecnologías simuladas analizando seis casos de estudios. Además se realizó la comparación de las técnicas desde el punto de vista técnico- económico para determinar cuál es la mejor alternativa. Según la evaluación económica de las técnicas, todas las alternativas analizadas son económicamente ventajosas y en todas se logran ganancias netas, pero los mayores beneficios se obtienen en la destilación extractiva con etilenglicol.

  4. CALIBRACIÓN DE LOS PARÁMETROS DE UN MODELO DE HORNO DE ARCO ELÉCTRICO EMPLEANDO SIMULACIÓN Y REDES NEURONALES

    Directory of Open Access Journals (Sweden)

    Mauricio Alexánder Álvarez López

    Full Text Available El horno de arco eléctrico proporciona un medio relativamente simple para la fusión de metales. Se utiliza en la producción de acero de alta pureza, aluminio, cobre, plomo, entre otros metales. Sin embargo, los hornos de arco son considerados como la carga más nociva para el sistema eléctrico de potencia. Por consiguiente, resulta de gran importancia contar con modelos de horno de arco que permitan determinar con alto grado de aproximación el comportamiento de este tipo de carga, puesto que se podría evaluar su impacto en términos de índices de calidad de energía para el sistema de potencia al cual se conecten. Uno de los principales problemas que surge al utilizar los modelos matemáticos de arco eléctrico consiste en la calibración de los parámetros que describen la dinámica del modelo. En este documento se muestra un procedimiento para calibrar todos los parámetros de un modelo de horno de arco eléctrico de corriente alterna, dadas mediciones reales de tensiones y corrientes. Se utiliza una red neuronal multicapa como emulador del modelo del horno. La red neuronal se entrena empleando datos de simulación obtenidos del modelo del horno implementado en el entorno Matlab®-Simulink®. Una vez entrenada la red, los parámetros de interés se obtienen resolviendo un problema inverso. Los resultados obtenidos muestran un error máximo de 4,1 % en el valor eficaz de las corrientes del arco eléctrico.

  5. EVALUACIÓN DE LA BIOTRANSFORMACIÓN DE GERANIOL Y (R-(+-α-PINENO EMPLEANDO CÉLULAS DE Rhodococcus opacus DSM 44313

    Directory of Open Access Journals (Sweden)

    JENNIFER PILAR ROJAS

    Full Text Available La alta biodisponibilidad de los monoterpenos los hace precursores promisorios en los procesos de biotransformación, mediante los que se producen compuestos de valor agregado que pueden considerarse naturales, debido a que se obtienen por métodos enzimáticos a partir de precursores aislados de la naturaleza. En el presente estudio se evaluó la biotransformación de geraniol y (R-(+-α-pineno empleando la cepa bacteriana Rhodococcus opacus DSM 44313, para ello se determinó la influencia del tiempo de crecimiento de la bacteria, tomando suspensiones celulares en la mitad y finalizando la fase exponencial. También se evaluaron tres tiempos de reacción (12, 24 y 48 h y el efecto de un cosolvente, agregando los sustratos puros y disueltos en etanol al 10%. A partir del geraniol se produjeron geranial, ácido geránico y 6-metil-5-hepten-2-ona, sólo cuando el sustrato se adicionó puro, y se formaron en mayor concentración cuando la bacteria estaba finalizando su fase de crecimiento exponencial. Con el (R-(+-α-pineno se produjo como compuesto principal el (R-(+-cis-verbenol, siendo mayor su concentración agregando el pineno disuelto en etanol, y cuando la bacteria se encontraba en la mitad de su fase de crecimiento exponencial. Los resultados indican que el comportamiento de la bacteria cambia según el sustrato adicionado, debido a las propiedades de cada monoterpeno, pero los compuestos obtenidos con ambos sustratos tienen importantes aplicaciones en las industrias farmacéutica, alimenticia y de perfumería

  6. Variables cognoscitivo-motivacionales relacionadas con el rendimiento escolar de estudiantes de bachillerato

    OpenAIRE

    Becerra González, Cruz Edgardo

    2016-01-01

    La eficiencia terminal del bachillerato mexicano es de 60% (SEP, 2012), el más bajo de todo el sistema. Una causa de deserción es que los jóvenes se rezagan en sus estudios. El rezago se mide empleando indicadores como el rendimiento escolar, y se estudia caracterizando a los estudiantes y a las variables relacionadas. Los objetivos de esta investigación fueron: 1) explicar si existían diferencias en motivación de logro, autoeficacia, estilo atribucional y rendimiento escolar de bachilleres, ...

  7. Grado de satisfacción laboral de los Directores de las Instituciones Educativas de Educación Básica Regular vinculadas al Programa de Educación Rural de Fe y Alegría Nº48 de Malingas –Tambogrande

    OpenAIRE

    Távara Ma-San, Carlos Gabriel

    2015-01-01

    La investigación tiene como objetivo identificar el grado de satisfacción laboral de los directores de las instituciones educativas de Educación Básica Regular vinculadas al Programa de Educación Rural de Fe y Alegría Nº 48 de Malingas –Tambogrande. Para ello, se aplicó de manera anónima a 25 directores un "Cuestionario de Satisfacción Laboral" constituido por 35 ítems como instrumento para cuantificar las ocho dimensiones relacionadas con la satisfacción laboral mediante procesamiento estadí...

  8. Eliminación de compuestos farmacéuticos y de cuidado personal (CFCPs) en efluentes anaerobios empleando sistemas biológicos de filtración/adsorción

    OpenAIRE

    Paredes Barro, Lidia

    2013-01-01

    Traballo Fín de Máster en Enxeñaría de Procesos Químicos e Ambientais. Curso 2012-2013 El objetivo principal de este Trabajo Fin de Máster es evaluar la eliminación de compuestos farmacéuticos y de cuidado personal (CFCPs) durante el tratamiento de efluentes anaerobios empleando sistemas biológicos de filtración/adsorción. Para la consecución de este objetivo global se han propuesto los siguientes objetivos específicos: 1-Estudiar cómo afecta el tipo de soporte empleado en el lecho (...

  9. Serviços bibliotecários para dispositivos móveis: O caso das bibliotecas vinculadas ao Conselho Nacional para Assuntos Bibliotecários das Instituições de Educação Superior do México

    Directory of Open Access Journals (Sweden)

    Eugenia de los Ángeles Ortega Martínez

    2016-11-01

    Full Text Available Objetivo: Analisar quais são os serviços bibliotecários e as aplicações (apps que se estão utilizando dentro das bibliotecas acadêmicas das Instituições de Educação Superior vinculadas ao Conselho Nacional para Assuntos Bibliotecários das Instituições de Educação Superior (CONPAB-IES, A. C. de México. Método: Foi realizado uma revisão da literatura em bancos de dados e revistas especializadas em Biblioteconomia e Ciências da Informação com ajuda dos recursos digitais da Direção Geral de Bibliotecas da Universidade Nacional Autônoma de México. Resultados e conclusões: O desenvolvimento de apps e serviços bibliotecários dispositivos móveis em bibliotecas acadêmicas das Instituições de Educação Superior,vinculadas ao CONPAB-IES, A. C., mostra uma tendência pelo desenvolvimento de coleções digitais em formatos amigaveis para PC e laptop, a diferença dos smartphones e tablets.

  10. Regeneración ósea en alvéolos dentarios de terceros molares mandibulares empleando plasma rico en plaquetas en pacientes fumadores

    Directory of Open Access Journals (Sweden)

    Fermín Gil Cárdenas

    2018-04-01

    Full Text Available Resumen: Objetivo: El propósito del trabajo fue evaluar la regeneración ósea en alvéolos dentarios empleando como coadyuvante PRP en pacientes fumadores. Materiales y método: Estudio de intervención cuasiexperimental; se asignaron 2 grupos de estudio, uno experimental y otro de control; se realizó exodoncia a los 2 grupos de los dientes 38 y 48. Al grupo control no se aplicó PRP y al experimental se le aplicó PRP con el método de una centrifugación en el alvéolo del diente 38 y PRP con doble centrifugación en alvéolo del diente 48; se realizaron controles radiográficos a los 8, 30 y 60 días después de la cirugía para evaluar la densidad ósea. Se realizó análisis estadístico descriptivo univariado, bivariado y prueba t de Student. Resultados: Hicieron parte del estudio 19 sujetos, el 52,6% de ellos fueron de sexo masculino, al estudiar la densidad ósea en los 3 controles radiográficos del grupo experimental en el alvéolo del diente 38 y 48, no se encontraron diferencias estadísticamente significativas (p > 0,05, pero sí una leve mejoría en la cicatrización del alvéolo 48 donde se empleó PRP con el método de doble centrifugación. Al comparar los controles radiográficos del grupo control con los del grupo experimental se encontraron valores estadísticamente significativos en el grupo que se le aplicó PRP con el método de una o doble centrifugación (p .05 were found in the experimental group in the sockets of tooth 38 and 48, but there was a slight improvement in the healing of socket 48 where PRP was used with the method of double centrifugation. On comparing the follow-up x-rays of the control with those of the experimental group, statistically significant values were found in the group where PRP was applied using the single or double centrifugation method (P<.05. Conclusions: The bone regeneration process is more favourable in

  11. Obtención y caracterización de monocristales de fosfatos cálcicos empleando el método de sales fundidas

    Directory of Open Access Journals (Sweden)

    Franco, J.

    2009-06-01

    fundidas, optimizando las condiciones de operación de este método para obtener una fase monocristalina con una relación de aspecto elevada, y cuya composición sea similar a la fase mineral del hueso. Se han estudiado los siguientes parámetros: composición del fundente, proporción material/fundente, y velocidad de enfriamiento. Los “whiskers” obtenidos se han caracterizado empleando difracción de rayos X de polvo cristalino (DRX, microscopía electrónica de barrido (MEB y microanálisis EDX. La estructura cristalina de los cristales de cloroapatito se determinó a partir de difracción de monocristal y de polvo cristalino.

  12. Medición del daño genético inducido por el basuco en linfocitos humanos empleando la prueba de micronúcleos con Citocalasina B

    Directory of Open Access Journals (Sweden)

    AP. Ocampo

    2001-07-01

    Full Text Available El bazuco es una mezcla compleja que se deriva del proceso de extracción de la cocaína. El frecuente consumo de bazuco constituye un problema de salud pública. La prueba de micronúcleos en linfocitos humanos de sangre periférica por bloqueo de la citocinesis con Citocalasina B, es más sensible y precisa para evaluar daño  cromosómico porque permite registrar micronúcleos originados de fragmentos de cromosomas o cromosomas enteros en células que se han dividido una sola vez. El objetivo del presente estudio fue evaluar el daño genético, inducido por el bazuco en linfocitos humanos in vitro empleando la prueba de micronúcleos con Citocalasina B.

  13. OXIDACIÓN POR VÍA HÚMEDA CATALÍTICA DE EFLUENTES INDUSTRIALES EMPLEANDO UN CATALIZADOR DE Pt SOPORTADO EN NANOTUBOS DE CARBONO DE PARED MÚLTIPLE

    Directory of Open Access Journals (Sweden)

    Gabriel Ovejero

    2011-01-01

    Full Text Available En el presente trabajo se ha estudiado la efectividad de la oxidación por vía húmeda catalítica para tratar aguas residuales industriales en un reactor por lote. Para ello se han realizado ensayos con un contaminante modelo, el colorante básico Amarillo Directo 11 empleando como catalizador platino soportado en nanotubos de carbono de pared múltiple (Pt/MWNT. Así mismo se ha realizado el tratamiento de dos efluentes industriales. Los resultados muestran tanto la alta efectividad del tratamiento en presencia del catalizador, como una importante disminución del carbono orgánico total y de la toxicidad en el efluente final. Se concluye que el proceso se ha demostrado eficaz tanto para el tratamiento del colorante básico ensayado, como en los dos efluentes residuales industriales.

  14. Producción científica de la psicología vinculada a pequeños productores agropecuarios con énfasis en el ámbito del desarrollo rural

    Directory of Open Access Journals (Sweden)

    Sofía Murtagh

    2011-01-01

    Full Text Available Con el objetivo de indagar los antecedentes científicos de la psicología en el trabajo con pequeños productores agropecuarios se examinó la base de datos PsycINFO (APA, identificándose 321 resúmenes que contenían conocimiento psicológico en relación al grupo social de interés. Posteriormente, estos trabajos fueron categorizados en torno a las variables (1 Área de la psicología, (2 Importancia dada a la categoría "pequeño productor agropecuario", (3 Región geográfica, (4 Metodología de investigación utilizada y (5 Década en la que fueron publicados. Finalmente, se analizó la distribución de cada una de las variables y la asociación entre ellas. Se concluye que las áreas de la psicología que contienen mayor cantidad de trabajos son Desarrollo y prácticas productivas, Salud y Social, llamando la atención la escasa presencia del área Educacional. Asimismo, se destaca la primera área mencionada, ya que no constituye un ámbito tradicional de aplicación de la psicología. Finalmente, se afirma la importancia de desarrollar los conocimientos de la psicología en relación al ámbito rural.

  15. Variability Bugs:

    DEFF Research Database (Denmark)

    Melo, Jean

    . Although many researchers suggest that preprocessor-based variability amplifies maintenance problems, there is little to no hard evidence on how actually variability affects programs and programmers. Specifically, how does variability affect programmers during maintenance tasks (bug finding in particular......)? How much harder is it to debug a program as variability increases? How do developers debug programs with variability? In what ways does variability affect bugs? In this Ph.D. thesis, I set off to address such issues through different perspectives using empirical research (based on controlled...... experiments) in order to understand quantitatively and qualitatively the impact of variability on programmers at bug finding and on buggy programs. From the program (and bug) perspective, the results show that variability is ubiquitous. There appears to be no specific nature of variability bugs that could...

  16. Pulsating variables

    International Nuclear Information System (INIS)

    1989-01-01

    The study of stellar pulsations is a major route to the understanding of stellar structure and evolution. At the South African Astronomical Observatory (SAAO) the following stellar pulsation studies were undertaken: rapidly oscillating Ap stars; solar-like oscillations in stars; 8-Scuti type variability in a classical Am star; Beta Cephei variables; a pulsating white dwarf and its companion; RR Lyrae variables and galactic Cepheids. 4 figs

  17. Metodología de valoración de paisaje empleando ArcGIS: Aplicación a las Vías Pecuarias

    Directory of Open Access Journals (Sweden)

    Ezquerra, A.

    2015-03-01

    Full Text Available The concept of landscape is assuming an increasing importance in legislation, and the Natural Heritage and Biodiversity Law requires a analysis of the landscape for the Natural Resources Ordination Plans. This calls for a range of tools to assist in studying the landscape prior to the assessment of management plans for natural resources. The advances in the techniques employed by Geographic Information Systems for assessing the landscape can be enhanced by the incorporation of numerous variables into the analysis. This work presents a landscape assessment methodology using GIS tools and including a number of variables which evaluate the landscape in terms of the viewshed and the distance from the observation point, applied to the specific case of the traditional cattle migration routes.El concepto de paisaje cada vez adquiere mayor importancia en la legislación porque también es importante el estudio del paisaje y todas las herramientas que pueden ayudar a su valoración en la gestión de los recursos naturales, ya que dentro de la Ley de Patrimonio Natural y Biodiversidad, es necesario el estudio del paisaje en los Planes de Ordenación de los Recursos Naturales. El avance de las técnicas que utilizan los Sistemas de Información Geográfica para la evaluación del paisaje permite agilizar su valoración con la introducción de numerosas variables que se incorporan en el análisis. Este trabajo presenta una metodología de valoración del paisaje utilizando herramientas SIG, introduciendo variables y valorándolas en función de la cuenca visual y de la distancia al punto de observación, aplicándolo al caso particular de las Vías Pecuarias.

  18. Cognitive Variability

    Science.gov (United States)

    Siegler, Robert S.

    2007-01-01

    Children's thinking is highly variable at every level of analysis, from neural and associative levels to the level of strategies, theories, and other aspects of high-level cognition. This variability exists within people as well as between them; individual children often rely on different strategies or representations on closely related problems…

  19. Análisis de mejora en la productividad del proceso de fabricación de rosquitas empleando un prototipo de formado de masa

    OpenAIRE

    Alvaro Humberto Velásquez Dávila

    2014-01-01

    Objetivos: Implementación de mejoras en la productividad del proceso de fabricación de rosquitas mediante el uso de un prototipo de máquina electromecánica de formado de tiras trenzadas para producir rosquitas. Métodos: En el proceso de fabricación del prototipo los diferentes componentes, como el largo y grosor del sin fin, la potencia de los moto reductores, la velocidad rotacional del tornillo y diferentes variables de operación, como temperatura de extrusión, humedad y temperatura inicial...

  20. DEVOTEES, WANNABES Y PRETENDERS: PARAFILIAS VINCULADAS A LA DISCAPACIDAD

    Directory of Open Access Journals (Sweden)

    Carolina Mora

    2016-01-01

    Full Text Available Con el desarrollo de internet se ha ido haciendo evidente la vinculación entre discapacidad y sexualidad, en la que las designaciones “devotees”, “pretedenders” y “wannabes” (DPW juegan un rol central. Los devotees son individuos sanos que se sienten atraídos sexualmente hacia personas con discapacidad, generalmente con problemas de movilidad. Los pretenders son personas que actúan como si tuvieran una discapacidad imitando sus movimientos, usando muletas, sillas de ruedas, escayolas, etc. Por último, los wannabes desean ser discapacitados, algunos de ellos han llegado al extremo de hacerse amputaciones caseras cuando la medicina tradicional se ha negado a dar respuesta a su necesidad. La presente investigación documental indaga sobre cada uno de los miembros de la taxonomía DPW, presentando: a las hipótesis existentes con relación a su etiología; b su vinculación con otras entidades diagnósticas presentes en el DSM V; c se describen algunos de los tratamientos que se han empleado en su abordaje terapéutico, y d se mencionan las interrelaciones entre estas 3 categorías, dado que los limites entre ellas son muy flexibles.

  1. Actividades físico-recreativas vinculadas al ajedrez para la ocupación del tiempo libre de niños entre 8-10 años de la Circunscripción 34 del Consejo Popular “Hermanos Barcón” del municipio Pinar del Río

    Directory of Open Access Journals (Sweden)

    Marisel Piñeiro Gomez

    2009-06-01

    Full Text Available Tomando como sustento que la comunidad resulta un contexto importante del trabajo social por ser en ella donde se dinamizan los procesos de participación para reafirmar los valores, la identidad es que se pretende proponer un conjunto de  actividades  físico  recreativas  vinculadas  al  ajedrez  para  la  ocupación  del tiempo libre de los niños y niñas entre 8/10 años de la Circunscripción 34 del Consejo Popular “Hermanos Barcón” del      municipio Pinar del Río. Sonrelacionadas con el ajedrez teniendo en consideración que sus propósitos generales están encaminados a desarrollar en el individuo una actitud favorable hacia el ajedrez que permita apreciarlo como elemento generador de cultura; desplegar su potencial intelectual a partir del estímulo de la esfera cognitiva; garantizar la adquisición de conocimientos, habilidades y destrezas básicas necesarias para la incorporación a la vida activa; permitir el establecimiento de vínculos entre los conocimientos, experiencias ajedrecistas y la vida cotidiana. Se realizó con una unidad de análisis desglosada en  32 del sexo masculino (39,5% y 49 del femenino (60,4%; para la muestra se escogieron a los niños y niñas que deseaban  ocupar  su  tiempo  libre  con  la  realización  de  actividades  físico recreativas vinculadas al ajedrez, quedando como sigue: Sexo masculino: 19 (59,3%  de  la  población; 79,1%  de  la  unidad  de  análisis, sexo  femenino: 23 (46,9% de la población; 63,8% de la unidad de análisis. La importancia de este trabajo es que fomentará hábitos de salud, disciplina, compañerismo, cooperación, responsabilidad; desarrollará habilidades de liderazgo; favorecerá a la integración, la comprensión, reconocimiento, desarrollo de agilidad mental, la capacidad para la solución de problemas, la creatividad, imaginación, curiosidad infantil, permitirá intercambiar ideas y experiencias durante su desarrollo.

  2. Modelo para gestionar el conocimiento en el sector textil de Medellín, empleando dinámica de sistemas

    Directory of Open Access Journals (Sweden)

    Natalia Marulanda Grisales

    2016-03-01

    Full Text Available Este artículo evalúa la relación de causalidad entre la gestión del conocimiento y las capacidades de innovación tecnológica, y el efecto de esta relación sobre los resultados operacionales del sector textil en la ciudad de Medellín. Se empleó la metodología de dinámica de sistemas, con simulación de esce­narios para valorar las condiciones actuales de las organizaciones del sector en términos de acumulación de conocimiento y capacidades. La información se obtuvo mediante entrevistas a expertos y acceso a información especializada del sector. Se evidencia que una mejora de la relación entre la gestión del conocimiento e innovación tecnológica genera un incremento aproximado del 15% en los ingresos operacionales del sector. Asimismo, se encontró que a medida que las variables comunes de interés (Es­trategias organizacionales, canales de comunicación, formación, cultura, acciones de fortalecimiento en I+D, se acercan a los valores deseados, la acumulación de conocimiento y de capacidades de innovación tecnológica alcanzan los valores objetivos. This paper analyses the causal relation between knowledge management and technological innovation capacities and the effect of this relation over the operational results of the textile sector for the city of Medellin. In order to value the current state of the organizations in the sector in terms of knowledge ac­cumulation and capacities, a dynamic system methodology with scenario simulation for evaluating the actual conditions was used. The information was obtained through interviews with experts and access­ing specialized information on the sector. It is evidenced that an improvement in the relation between knowledge management and technological innovation generates and approximated increase of 15% over the operational revenue of the sector. Likewise, it was found that in the measure that common variables of interest (organizational strategies, communication channels

  3. Obtención de silicatos de calcio empleando como precursores residuos sólidos. Influencia del mezclado de reactivos en fase seca o fase húmeda

    Directory of Open Access Journals (Sweden)

    Corpas Iglesias, F. A.

    2011-02-01

    Full Text Available The suitability of re-using residues marble, remaining from cutting marble, as a source of calcium-oxide, as well as the resultant ashes from the combustion of the wastes generated in the process of manufacturing boards from derivates of wood, as a source of silica, as raw material for the production of calcium silicate products has been determined. First of all, the influence of water has been studied in the initial phase of mixing residues. Marble and ashes have been mixed in molar relation CaO:SiO2 of 1:1 using two different ways: using a planetary ball mill (while in solid state or agitating at 90 ºC (2 h using a 60 wt% of water (while in humid state. Later, both mixtures were sintered at 1100 ºC (24 h. In order to use the obtained calcium-silicates as ceramic insulating thermal materials, the samples were compressed at 15 Tm obtaining bricks from which the technological properties have been studied. The ceramic materials obtained from mixing the residues in dry phase, as well as those obtained in the wet phase, can be used as thermal insulators, showing values of conductivity of 0.18 and 0.12 w/m2K, with an elevated resistance to compressive strength.

    Se ha determinado la posibilidad de reutilizar los residuos procedentes del corte de mármol, como fuente de óxido de calcio, y las cenizas resultantes de la combustión de los residuos generados en el proceso de fabricación de tableros de derivados de madera, como fuente de sílice. A partir de ambas materias primas, se obtienen silicatos de calcio. Se ha estudiado la influencia de agua en la fase inicial de mezclado de los residuos. Para ello mármol y cenizas se han mezclado en relación molar CaO:SiO2 1:1, en una primera ruta, en fase seca, empleando un molino de bolas, o en una segunda ruta, en fase húmeda, mediante agitación a 90 ºC (2 h empleando un 60 % en peso de agua. Posteriormente, ambas mezclas se sinterizan a 1100 ºC (24 h. Con

  4. IMPLEMENTACIÓN DE UN SISTEMA DE MEDICIÓN DE TEMPERATURA EMPLEANDO FIBRA ÓPTICA PARA EL ESTUDIO TÉRMICO DE TRANSFORMADORES DE DISTRIBUCIÓN INMERSOS EN ACEITE MINERAL Y VEGETAL

    Directory of Open Access Journals (Sweden)

    Diego Fernando Navas

    Full Text Available Los transformadores son elementos de suma importancia dentro de las redes eléctricas. Su vida útil depende, entre otros factores, de la temperatura presente en su interior, especialmente aquella localizada en sus materiales aislantes. Dichas temperaturas suelen ser estimadas a través de modelos propuestos en las normatividades; sin embargo, los valores obtenidos son aproximados y siempre es deseable obtener una medición directa. Por razones netamente económicas la medición directa suele emplearse en transformadores de potencia. Sin embargo, con la llegada de las smarts grids (redes inteligentes será necesaria la instrumentación en los sistemas de distribución y el uso de tecnologías más limpias. Con fines investigativos, en el presente documento los autores comentan sus experiencias en la instrumentación con fibras ópticas de cuatro transformadores de distribución sumergidos en aceite mineral y vegetal para realizar una evaluación térmica. Los transformadores tienen capacidades de 15 kVA y 37,5 kVA y operan a tensiones de 7620 V / 240 V. Se explica el proceso de determinación de los puntos de medición de temperatura al interior del transformador y se finaliza con resultados de ensayos de elevación de temperatura empleando carga simulada mediante cortocircuito y carga real a dos niveles para comparar las mediciones dentro de cada uno de los transformadores.

  5. Desempeño del método cromatográfico para el estudio de estabilidad del aceite de hígado de tiburón microencapsulado empleando acetato de quitosana

    Directory of Open Access Journals (Sweden)

    Caridad García

    Full Text Available Objetivo: Evaluar el desempeño del método para la cuantificación de la vitamina A en el aceite microencapsulado, empleando acetato de quitosana y maltodextrina como agentes encapsulantes, así como estudiar la estabilidad del aceite microencapsulado. Materiales y métodos: Los parámetros evaluados se correspondieron con lo establecido internacionalmente para este estudio: especificidad, exactitud y precisión. El estudio de estabilidad se realizó durante 12 meses a temperatura ambiente (30 ± 2ºC y 70 ± 5 % de humedad relativa, evaluándose en el tiempo la eficiencia de encapsulación, aceite superficial, pérdidas por desecación, contenido de vitamina A y conteo microbiológico. Resultados: Se demostró que el método evaluado fue específico, preciso y exacto para la determinación del contenido de vitamina A en la mezcla de aceite microencapsulado. Los resultados demuestran que el aceite microencapsulado tiene un comportamiento estable en cuanto a los indicadores evaluados, evidenciándose la protección ofrecida por los componentes de la pared de las microcápsulas. Conclusiones: El método empleado en la cuantificación de la vitamina A en el aceite microencapsulado resultó específico, exacto y preciso, demostrándose su aplicabilidad para el control de calidad y estudio de estabilidad. El aceite microencapsulado con acetato de quitosana y maltodextrina como agentes encapsulantes, es estable física, química y microbiológicamente, durante 12 meses.

  6. Análisis de mejora en la productividad del proceso de fabricación de rosquitas empleando un prototipo de formado de masa

    Directory of Open Access Journals (Sweden)

    Alvaro Humberto Velásquez Dávila

    2014-12-01

    Full Text Available Objetivos: Implementación de mejoras en la productividad del proceso de fabricación de rosquitas mediante el uso de un prototipo de máquina electromecánica de formado de tiras trenzadas para producir rosquitas. Métodos: En el proceso de fabricación del prototipo los diferentes componentes, como el largo y grosor del sin fin, la potencia de los moto reductores, la velocidad rotacional del tornillo y diferentes variables de operación, como temperatura de extrusión, humedad y temperatura inicial de la masas de rosquita, se modificaron a fin de encontrar las condiciones óptimas de operación para que la rosquita sea de excelente calidad y no varíe sus condiciones de sabor, forma y estructura reconocidas en el mercado. Resultados: Se diseñó un prototipo con un mecanismo de extrusión compuesto por un tornillo sin fin situado en una carcasa. En un extremo de dicha carcasa se ubica una tolva de alimentación de la masa de rosquita y por el otro se extruiría tiras por boquillas que al girarlas darían el trenzado de tiras requerido para el formado de la masa de rosquita. Se llevaron a cabo pruebas variando la humedad de la masa en 37, 30 y 26%, variando la temperatura de la masa y las revoluciones del tornillo sin fin. Conclusiones: Luego de las pruebas de humedad, temperatura y calidad, el mejor producto se obtuvo al utilizar una velocidad rotacional de 56 rpm, 26% de humedad y utilizando masa a 25° de temperatura. Asimismo, en términos económicos se ha logrado incrementar la productividad del negocio de rosquitas. Los costos de producción se han reducido en un 21% y el proyecto arroja un VAN positivo de S/. 7M.

  7. Complex variables

    CERN Document Server

    Fisher, Stephen D

    1999-01-01

    The most important topics in the theory and application of complex variables receive a thorough, coherent treatment in this introductory text. Intended for undergraduates or graduate students in science, mathematics, and engineering, this volume features hundreds of solved examples, exercises, and applications designed to foster a complete understanding of complex variables as well as an appreciation of their mathematical beauty and elegance. Prerequisites are minimal; a three-semester course in calculus will suffice to prepare students for discussions of these topics: the complex plane, basic

  8. Variable stars

    International Nuclear Information System (INIS)

    Feast, M.W.; Wenzel, W.; Fernie, J.D.; Percy, J.R.; Smak, J.; Gascoigne, S.C.B.; Grindley, J.E.; Lovell, B.; Sawyer Hogg, H.B.; Baker, N.; Fitch, W.S.; Rosino, L.; Gursky, H.

    1976-01-01

    A critical review of variable stars is presented. A fairly complete summary of major developments and discoveries during the period 1973-1975 is given. The broad developments and new trends are outlined. Essential problems for future research are identified. (B.R.H. )

  9. Optimización de las condiciones de extracción de compuestos fenólicos a partir de cáscara de uva variedad quebranta (Ica, Perú) empleando técnicas convencionales y extracción asistida por ultrasonido

    OpenAIRE

    Dueñas Zurita, Julia Alicia

    2017-01-01

    La producción de vino y pisco representa una de las principales actividades agrícolas en todo el mundo, esta producción se acompaña con la generación de grandes cantidades de desechos que son ricos en compuestos bioactivos (especialmente compuestos fenólicos) con capacidad antioxidante. El propósito de este trabajo es seleccionar y optimizar las condiciones de extracción de compuestos fenólicos a partir de cáscara de uva variedad Quebranta provenientes de vinificaciones empleando un método co...

  10. Complex variables

    CERN Document Server

    Flanigan, Francis J

    2010-01-01

    A caution to mathematics professors: Complex Variables does not follow conventional outlines of course material. One reviewer noting its originality wrote: ""A standard text is often preferred [to a superior text like this] because the professor knows the order of topics and the problems, and doesn't really have to pay attention to the text. He can go to class without preparation."" Not so here-Dr. Flanigan treats this most important field of contemporary mathematics in a most unusual way. While all the material for an advanced undergraduate or first-year graduate course is covered, discussion

  11. Síntesis de espumas rígidas de poliuretano obtenidas a partir de aceite de castor y poliglicerol empleando calentamiento por microondas Synthesis of rigid polyurethane foams obtained from castor oil and polyglycerol using microwave heating

    Directory of Open Access Journals (Sweden)

    Paula Mazo

    2011-01-01

    Full Text Available En este trabajo se realizó la síntesis de espumas rígidas de poliuretano utilizando un macropoliol sintetizado a partir de aceite de castor y poliglicerol, se optimizó mediante un análisis de superficie de respuesta, empleando un diseño factorial 32, los factores evaluados fueron: cantidad de agua y de ácido tartárico, el cual actúa como agente entrecruzante y catalizador; se evalúaron las propiedades mecánicas de las espumas como: densidad aparente (ASTM D1622-08, resistencia a la compresión (ASTM D1621, conductividad térmica (ASTM C177-04 y friabilidad (ASTM C421-8; se realizó Microscopia Electrónica de Barrido (SEM y Análisis de Calorimetría Diferencial de Barrido (DSC. El macropoliol fue obtenido desde fuentes renovables, mediante la transesterificación de Aceite de Castor (CO ó Aceite de Castor Maleinizado (MACO con Poliglicerol (PG. Se evalúo el efecto de las microondas en las reacciones, donde se encuentra una disminución del tiempo; el seguimiento y la caracterización de los productos intermedios se realiza mediante la cuantificación de valor ácido por titulación (ASTM D4662-03 y número de hidroxilos (ASTM D4274-05.In this work we showed the polyurethane rigid foams synthesis using a macropolyol synthesized from castor oil and polyglycerol. This process is optimized employing a response surface analysis and using a 3² factorial design. The factors evaluated were: amount of water and tartaric acid, where tartaric acid acts as crosslinking agent and catalyst; mechanical properties of foams were evaluated as bulk density (ASTM D1622-08, compressive strength (ASTM D1621, thermal conductivity (ASTM C177-04, and friability (ASTM C421-8; scanning electronic microscopic (SEM and differential scanning calorimetry (DSC. The macropolyol was obtained from renewable sources by the transesterification of castor oil (CO or maleinized castor oil (MACO and polyglycerol (PG. The effect of microwaves on the reactions was

  12. Variable collimator

    International Nuclear Information System (INIS)

    Richey, J.B.; McBride, T.R.; Covic, J.

    1979-01-01

    This invention describes an automatic variable collimator which controls the width and thickness of X-ray beams in X-ray diagnostic medical equipment, and which is particularly adapted for use with computerized axial tomographic scanners. A two-part collimator is provided which shapes an X-ray beam both prior to its entering an object subject to radiographic analysis and after the attenuated beam has passed through the object. Interposed between a source of radiation and the object subject to radiographic analysis is a first or source collimator. The source collimator causes the X-ray beam emitted by the source of radiation to be split into a plurality of generally rectangular shaped beams. Disposed within the source collimator is a movable aperture plate which may be used to selectively vary the thickness of the plurality of generally rectangular shaped beams transmitted through the source collimator. A second or receiver collimator is interposed between the object subject to radiographic analysis and a series of radiation detectors. The receiver collimator is disposed to receive the attenuated X-ray beams passing through the object subject to radiographic analysis. Located within the receiver collimator are a plurality of movable aperture plates adapted to be displaced relative to a plurality of fixed aperture plates for the purpose of varying the width and thickness of the attenuated X-ray beams transmitted through the object subject to radiographic analysis. The movable aperture plates of the source and receiver collimators are automatically controlled by circuitry which is provided to allow remote operation of the movable aperture plates

  13. Bioremediation of soil contaminated with hydrocarbons using sewage sludge as an alternative source of nutrients; Biorremediacion de suelo contaminado con hidrocarburos empleando lodos residuales como fuente alterna de nutrientes

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Prado, Adriana [Instituto Tecnologico de Durango, Durango, Durango (Mexico)]. E-mail: adriana.martinez@orst.edu; Perez Lopez, Ma. Elena [Centro Interdisciplinario de Investigacion para el Desarrollo Integral Regional (IPN-CIIDIR) Unidad Durango, Durango, Durango (Mexico); Pinto Espinoza, Joaquin; Gurrola Nevarez, Blanca Amelia; Osorio Rodriguez, Ana Lilia [Instituto Tecnologico de Durango, Durango, Durango (Mexico)

    2011-07-01

    In this research an aerobic bioremediation process, of a petroleum hydrocarbon contaminated soil, was evaluated using residual sludge (biosolids) from a local domestic wastewater treatment plant, as an alternative micro and macro nutrient source. Contamination of the soil resulted from accidental spills with hydrocarbons, mainly diesel, gasoline, and residual oils, from the San Antonio mining unit which belongs to Goldcorp Mexico Company, located in Tayoltita, from the municipality of San Dimas, Durango. Laboratory and pilot experiments were conducted, adjusting soil water content to field capacity and carbon:nitrogen (C:N) ratio to 10:1, evaluating the effect of addition of nutrients, density of the material being remediated, and the influence of soil particle size in the remediation process. It was demonstrated that the biosolids stimulated the native microorganisms of the polluted soil; consequently the hydrocarbon degradation process was accelerated. The hydrocarbons were used as carbon and electron donor source, coupling the oxidation-reduction reaction with oxygen which served as the electron acceptor. Treated soil was remediated and reached the maximum permissible limit (MPL), established in the Mexican current regulations (NOM-138-SEMARNAT/SS-2003), at both stages, and it is recommended as an optional process to the mining company to fulfill with the Clean Industry Program. [Spanish] En la presente investigacion se evaluo el proceso de biorremediacion aerobica de un suelo contaminado con hidrocarburos de petroleo empleando lodos residuales (biosolidos), provenientes de una planta de tratamiento de aguas residuales (PTAR) domesticas de la localidad, como fuente alterna de macro y micronutrientes. La contaminacion del suelo fue resultado de derrames accidentales de diesel, aceite y grasas en la unidad minera San Antonio perteneciente al grupo Goldcorp Mexico, ubicada en el municipio de San Dimas, en Tayoltita, Durango. Se realizaron experimentos a escala

  14. Evaluación y estandarización del análisis por activación neutrónica según el método del k-sub cero en el reactor nuclear RP-10: Estudio preliminar empleando irradiaciones cortas

    OpenAIRE

    Montoya Rossi, Eduardo Haroldo

    1995-01-01

    Se ha estandarizado una posición de irradiación del reactor nuclear RP-10 para el uso del análisis por activación neutrónica según el método del k sub cero, empleando la convención de Högdahl y se ha evaluado el comportamiento de dicho método respecto a la exactitud y precisión de los resultados obtenidos en el análisis multielemental cuantitativo de diversos materiales certificados de referencia. Para comprobar que el método analítico se encuentra totalmente bajo control estadístico, se ha e...

  15. Identidad de la vacuna contra Streptococcus pneumoniae “Quimi-Vio” mediante la técnica Dot Blot empleando los anticuerpos monoclonales contra los polisacáridos capsulares 1,5, 6B, 14 y 19F de la bacteria

    Directory of Open Access Journals (Sweden)

    Elizabeth González Aznar

    2017-02-01

    Full Text Available Streptococcus pneumoniae (neumococo constituye una de las principales causas de enfermedades infecciosas bacterianas, particularmente en niños menores de 2 años de edad. Basadas en el polisacárido capsular (PsC, su principal factor de virulencia, existen dos tipos de vacunas aprobadas para uso en humanos: las vacunas polisacarídicas planas y las vacunas polisacarídicas conjugadas. Quimi-Vio, la vacuna antineumocócica cubana, pertenece al segundo grupo y está compuesta por los PsC de los siete serotipos de mayor incidencia y circulación en Cuba (1, 5, 6B, 14, 18C, 19F y 23F. El objetivo de este trabajo fue realizar el ensayo de identidad de la vacuna cubana Quimi-Vio empleando los AcM contra los PsC 1, 5, 6B, 14, y 19F de Sp obtenidos recientemente en el Instituto Finlay de Vacunas, teniendo en cuenta que los Ensayos de identidad de las vacunas son requisito indispensable para la liberación final de los lotes. La técnica empleada para la realización del ensayo de identidad de Quimi-Vio fue el Dot Blot, donde empleando membrana de Nitrocelulosa se realizó la captura de tres lotes de vacuna Quimi-Vio y como control positivo de la técnica los respectivos PsC de los serotipos 1, 5, 6B, 14, y 19F sin conjugar y una vacuna comercial Prevenar-13. Para la identidad de los PsC de neumococo se emplearon los respectivos AcM a una concentración de 10µg/mL y como segundo anticuerpo anti IgG de ratón conjugado a peroxidasa teniendo en cuenta que los AcMs empleados son murinos. Cada AcM fue capaz de identificar de forma altamente especifica al PsC homologo (mismo serotipo, tanto en su forma no conjugada y monovalente como en el contexto de las vacunas Quimi-Vio y Prevenar 13V, donde además de estar conjugado al TT se encuentra mezclado con otros PsC de forma multivalente. La técnica Dot Blot empleando los AcMs contra los PsC serotipos 1, 5,6B, 14 y 19F permite identificar de forma específica cada PsC en la formulación multivalente, por lo

  16. Variable importance in latent variable regression models

    NARCIS (Netherlands)

    Kvalheim, O.M.; Arneberg, R.; Bleie, O.; Rajalahti, T.; Smilde, A.K.; Westerhuis, J.A.

    2014-01-01

    The quality and practical usefulness of a regression model are a function of both interpretability and prediction performance. This work presents some new graphical tools for improved interpretation of latent variable regression models that can also assist in improved algorithms for variable

  17. Análisis de variables psicopedagógicas en hijos adolescentes violentos desde el modelo cognitivo

    Directory of Open Access Journals (Sweden)

    Cristian Molla Esparza

    2018-04-01

    Full Text Available La violencia filio-parental es una realidad latente en nuestra sociedad. El presente artículo analiza la existencia o no de variables psicopedagógicas (académica y laboral como factores de riesgo en hijos adolescentes que ejercen violencia contra sus progenitores. La metodología utilizada es descriptiva, centrada en el análisis de estudios que contemplan estas variables y las comparan con investigaciones sobre hijos agresores. Los resultados sugieren que éstos son factores de riesgo de conductas violentas en adolescentes por violencia filial y esbozan cuestiones relevantes para la investigación, prevención e intervención educativa. Asimismo, desde el modelo cognitivo, se intenta explicar la interacción entre la cognición intrapersonal e impersonal, principalmente, en adolescentes violentos; así como, las habilidades cognitivas vinculadas a la conducta prosocial frente a disposiciones antisociales, con miras a la intervención socioeducativa.

  18. Control de velocidad del motor de indución empleando linealización por realimentación de estados Speed control of induction motor using state feedback linearization

    OpenAIRE

    Eduardo Giraldo Suárez; Santiago Sánchez Acevedo

    2009-01-01

    Este documento presenta la aplicación de la técnica de control no lineal clásica llamada linealización por realimentación de variables de estado. Se hace una aplicación en el motor de inducción, la variable a controlar es la velocidad del eje del motor, el sistema emplea el esquema de control vectorial para máquinas de corriente alterna desarrollado en las últimas décadas; este método es análogo a la técnica de control del motor de corriente directa. El modelo del motor de inducción se descri...

  19. Control de velocidad del motor de indución empleando linealización por realimentación de estados Speed control of induction motor using state feedback linearization

    Directory of Open Access Journals (Sweden)

    Eduardo Giraldo Suárez

    2009-01-01

    Full Text Available Este documento presenta la aplicación de la técnica de control no lineal clásica llamada linealización por realimentación de variables de estado. Se hace una aplicación en el motor de inducción, la variable a controlar es la velocidad del eje del motor, el sistema emplea el esquema de control vectorial para máquinas de corriente alterna desarrollado en las últimas décadas; este método es análogo a la técnica de control del motor de corriente directa. El modelo del motor de inducción se describe en el sistema de coordenadas de campo orientado del flujo de rotor y se muestra una introducción al producto y la derivada de Lie, empleados en el diseño del controlador no lineal.This articles shows the application of a classic non-linear control technique called "linearization by feedback of status variables." An application on the induction engine is made. Variable to be controlled is speed of the engine shaft. The system employs a vectorial control scheme for AC engines developed during the last decades. This is a method analogous to the DC engine control technique. Induction engine model is described in the guided field coordinate system of rotor flow. Introduction to the product and Lie derivative used for designing the non-linear controller are shown.

  20. Determinación de la tenacidad a la fractura de muestras de Acero 45 fundido, empleando las correlaciones entre el KIC y la energía de impacto medida en el ensayo de Charpy. // Determination of the fracture tenacity of cast Steel grade 45 samples, using th

    Directory of Open Access Journals (Sweden)

    F. Ramos Morales

    2005-05-01

    Full Text Available En el presente trabajo se determinan los valores de tenacidad a la fractura (KIC de muestras de Acero 45 fundido,empleando las correlaciones entre la tenacidad a la fractura y la energía de impacto (CVN obtenida del ensayo de Charpy.Se hace una discusión sobre las correlaciones que más se ajustan en la región de transición y en upper shelf. Se comparanlos valores obtenidos de estas correlaciones a valores de tenacidad a la fractura establecidos en la literatura.Palabras claves: Fractura, energía de impacto, acero fundido.______________________________________________________________________________Abstract.In this paper, the values of fracture toughness (KIC are determined on specimens of cast steel grade 45, using thecorrelations among the fracture toughness (KIC and the impact energy (CVN obtained from a Charpy test. A discussion ismade on the correlations that are better adjusted in the transition region and in upper shelf region. The obtained values arecompared from these correlations to values of fracture toughness (KIC settled down in the literature.Key words. Fracture, impact energy, cast steel.

  1. Amplification factor variable amplifier

    NARCIS (Netherlands)

    Akitsugu, Oshita; Nauta, Bram

    2007-01-01

    PROBLEM TO BE SOLVED: To provide an amplification factor variable amplifier capable of achieving temperature compensation of an amplification factor over a wide variable amplification factor range. ; SOLUTION: A Gilbert type amplification factor variable amplifier 11 amplifies an input signal and

  2. Amplification factor variable amplifier

    NARCIS (Netherlands)

    Akitsugu, Oshita; Nauta, Bram

    2010-01-01

    PROBLEM TO BE SOLVED: To provide an amplification factor variable amplifier capable of achieving temperature compensation of an amplification factor over a wide variable amplification factor range. ;SOLUTION: A Gilbert type amplification factor variable amplifier 11 amplifies an input signal and can

  3. Variable mechanical ventilation.

    Science.gov (United States)

    Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini, Luiz Alberto; Friedman, Gilberto

    2017-01-01

    To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

  4. Evaluación de la transferencia de oxígeno en cultivos con lactococcus lactis empleando un sistema de fermentación con aireación externa

    Directory of Open Access Journals (Sweden)

    Andrea Soler

    2010-07-01

    Full Text Available Título en inglés: Evaluating oxygen transfer in a Lactococcus lactis cultures using an external aeration fermentation system (EAFS Resumen En fermentaciones aerobias el oxígeno, como aceptor terminal de electrones en el proceso de respiración, comúnmente se constituye en limitante debido entre otros factores al diseño del biorreactor (factores geométricos, a las condiciones de operación de los fermentadores (condiciones ambientales requeridas en el cultivo, potencia transferida al cultivo por el sistema de agitación, propiedades del medio líquido, demanda de oxígeno por parte del microorganismo, sistema de aireación (concentración de oxígeno en el gas, solubilidad del oxígeno. La limitación de oxígeno se refleja en la fermentación con Lactococcus lactis cepa IBUN 34.1, en que presenta una baja disponibilidad de oxígeno desde muy temprano en la fase exponencial del cultivo. Para superar estas limitaciones se diseñó y desarrolló un sistema de suministro de oxígeno de alta tasa de transferencia, consistente en un sistema de fermentación con aireación externa (SFAE, el cual es comparado en este trabajo con el sistema tradicional de fermentador agitado dotado con dos turbinas tipo Rushton y aireación por difusor interno. En este trabajo se evalúa la operación del SFAE, se seleccionan y estudian algunas variables operacionales y su efecto sobre la transferencia de oxígeno gas-líquido. Los resultados indican que las variables que tienen efecto significativo sobre el coeficiente volumétrico global de transferencia de masa kLa son la agitación y el flujo de medio de cultivo que circula por el aireador externo denominado flujo de recirculación. Los valores de kLa obtenidos indican que con el fermentador convencional con aireación interna el mayor valor de kLa alcanzado fue de 40,68 (h-1, en tanto que con el SFAE se alcanzaron valores de 63,18 (h-1. Palabras clave: biorreactores; kLa; transferencia de ox

  5. Cataclysmic Variable Stars

    Science.gov (United States)

    Hellier, Coel

    2001-01-01

    Cataclysmic variable stars are the most variable stars in the night sky, fluctuating in brightness continually on timescales from seconds to hours to weeks to years. The changes can be recorded using amateur telescopes, yet are also the subject of intensive study by professional astronomers. That study has led to an understanding of cataclysmic variables as binary stars, orbiting so closely that material transfers from one star to the other. The resulting process of accretion is one of the most important in astrophysics. This book presents the first account of cataclysmic variables at an introductory level. Assuming no previous knowledge of the field, it explains the basic principles underlying the variability, while providing an extensive compilation of cataclysmic variable light curves. Aimed at amateur astronomers, undergraduates, and researchers, the main text is accessible to those with no mathematical background, while supplementary boxes present technical details and equations.

  6. Understanding Brown Dwarf Variability

    Science.gov (United States)

    Marley, Mark S.

    2013-01-01

    Surveys of brown dwarf variability continue to find that roughly half of all brown dwarfs are variable. While variability is observed amongst all types of brown dwarfs, amplitudes are typically greatest for L-T transition objects. In my talk I will discuss the possible physical mechanisms that are responsible for the observed variability. I will particularly focus on comparing and contrasting the effects of changes in atmospheric thermal profile and cloud opacity. The two different mechanisms will produce different variability signatures and I will discuss the extent to which the current datasets constrain both mechanisms. By combining constraints from studies of variability with existing spectral and photometric datasets we can begin to construct and test self-consistent models of brown dwarf atmospheres. These models not only aid in the interpretation of existing objects but also inform studies of directly imaged giant planets.

  7. The nebular variables

    CERN Document Server

    Glasby, John S

    1974-01-01

    The Nebular Variables focuses on the nebular variables and their characteristics. Discussions are organized by type of nebular variable, namely, RW Aurigae stars, T Orionis stars, T Tauri stars, and peculiar nebular objects. Topics range from light variations of the stars to their spectroscopic and physical characteristics, spatial distribution, interaction with nebulosity, and evolutionary features. This volume is divided into four sections and consists of 25 chapters, the first of which provides general information on nebular variables, including their stellar associations and their classifi

  8. Ultrasonic variables affecting inspection

    International Nuclear Information System (INIS)

    Lautzenheiser, C.E.; Whiting, A.R.; McElroy, J.T.

    1977-01-01

    There are many variables which affect the detection of the effects and reproducibility of results when utilizing ultrasonic techniques. The most important variable is the procedure, as this document specifies, to a great extent, the controls that are exercised over the other variables. The most important variable is personnel with regards to training, qualification, integrity, data recording, and data analysis. Although the data is very limited, these data indicate that, if the procedure is carefully controlled, reliability of defect detection and reproducibility of results are both approximately 90 percent for reliability of detection, this applies to relatively small defects as reliability increases substantially as defect size increases above the recording limit. (author)

  9. Selection of new drill sites using a Geographic Information System (GIS) at Los Azufres, Mexico; Seleccion de nuevos sitios de perforacion empleando un Sistema de Informacion Geografica (SIG) en Los Azufres, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Estrada, G.H [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)]. E-mail: gerardo.garcia04@cfe.gob.mx; Lopez-Hernandez, A [Facultad de Ingenieria Civil, Universidad Michoacana de San Nicolas de Hidalgo, Morelia (Mexico); Quijano Leon, J.L Cuauhtemoc [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2008-07-15

    GIS technology is used to study the effects of distance between producing wells and superficial-thermal features and faults. It is used to interpret topographic lineaments and linear-resistivity interfaces at depth to identify hidden faults. Finally, a geothermal interpretation is conducted by applying a Multi-Criteria Evaluation Method (MCE) on a comprehensive data set, including geology, geophysics, and well production data. Visual comparisons of exploratory and drilling-data maps, with thermal discharge measured from wells, were used to select variables and data ranges that could be more directly associated with energy-production levels. Relative weights assigned by visual inspection are used to extend this knowledge to the whole exploration area. Criteria are compared to calculate a geothermal index representing the geothermal-production suitability for each cell into which the study area is divided. Considering the geometry of fault planes at depths from 700 to 2000 m below the surface, and a 250 m exclusion zone around productive wells, we choose areas from the normalized-geothermal index to propose new drill sites with different levels of risk, ranging from production (low risk) to exploration (high risk) boreholes. [Spanish] Se empleo la tecnologia de Sistemas de Informacion Geografica (SIG) para estudiar el efecto de la distancia de los pozos productores a las manifestaciones termales superficiales y a las fallas, y para interpretar los lineamientos topograficos y las interfaces lineales de resistividad a profundidad para identificar fallas ocultas. Finalmente, se realizo una interpretacion geotermica aplicando un Metodo Multi-Criterio de Evaluacion (MCE) a un conjunto completo de datos que incluye geologia, geofisica y datos de produccion de pozos. Se utilizo una comparacion visual de mapas de datos de exploracion y perforacion con descargas termicas medidas en pozos, a fin de seleccionar variables y rangos de datos que podrian asociarse mas directamente

  10. Connected analysis nuclear-thermo-hydraulic of parallel channels of a BWR reactor using distributed computation; Analisis acoplado nuclear-termohidraulico de canales paralelos de un reactor BWR empleando computacion distribuida

    Energy Technology Data Exchange (ETDEWEB)

    Campos Gonzalez, Rina Margarita

    2007-07-15

    This work consists of the integration of three models previously developed which are described widely in Literature: model of the thermo-hydraulic channel, model of the modal neutronic and the model of the recirculation bows. The tool used for this connection of models is the PVM system, Parallel Virtual Machine that allowed paralleling the model by means of the concept of distributed computation. The purpose of making this connection of models is the one of obtaining a more complete tool than better represents the real configuration and the phenomenology of the nucleus of a BWR reactor, thus obtaining better results. In addition to maintaining the flexibility to improve the resulting model at any time, since the very complex or sophisticated models are difficult to improve being impossible to modify the equations they use and can include variables that are not of primary importance in the tackled problem or that mask relations among variables due to the excess of results. Also maintaining the flexibility for adding component of models or systems of the BWR reactor, all of this following the modeling needs. The Swedish Ringhals power plant was chosen to characterize the resulting connected model for counting on a Stability Benchmark that offers the opportunity to count on real plant data. Besides that in case 9 of cycle 14 of this Benchamark oscillations outside phase appeared, which are from great interest because the detection systems that register the average of the power of the nucleus do not detect them. Additionally in this work the model of the recirculation bows as an independent module is obtained in an individual way, since this model belongs to another work and works connected to the reactor vessel. The model of the recirculation bows is able to model several transients of interest, as it is shown in the Appendix A of this work, among which are found the tripping of recirculation pumps or the transference at low or high velocity of them. The scope of the

  11. Descripción de la dinámica interna de las familias monoparentales, simultáneas, extendidas y compuestas del municipio de Medellín, vinculadas al proyecto de prevención temprana de la agresión

    Directory of Open Access Journals (Sweden)

    María Eugenia Agudelo Bedoya

    2005-05-01

    Full Text Available El estudio efectuado por el Grupo de Investigaciones en Familia de la U.P.B., caracteriza la dinámica interna de las diferentes tipologías familiares en las Comunas 1, 2, 3, 8 y 9 del Municipio de Medellín que participaron en el proyecto de “Prevención Temprana de la Violencia, Pautas de Educación y Crianza” que se desarrolló entre enero de 2001 y septiembre de 2002, contando con la financiación del Municipio de Medellín y el Banco Interamericano de Desarrollo (BID. Se analiza la dinámica interna de 536 familias distribuidas por tipología de la siguiente manera: 204 Monoparentales Femeninas; 11 Monoparentales Masculinas; 173 Extendidas; 109 Simultáneas y 39 Compuestas.La información se tomó de los registros de visita domiciliaria y entrevistas aplicados directa y personalmente por el grupo de asesores que tuvo a su cargo el proceso formativo y de orientación con las familias de niños y niñas de las instituciones educativas participantes. Es importante anotar que el modelo de intervención incluye la aplicación del cuestionario para evaluación de conductas en niños/niñas entre 3 y 11 años de edad (COPRAG, que permite identificar si están en riesgo de asumir conductas agresivas. Según el puntaje que obtienen en dicha prueba, se clasifican en 2 categorías: en la de "Índice" los niños y las niñas que aparecen en mayor riesgo y en la de "no Índice" quienes aparecen en menor riesgo. Por esto, el análisis de la información se hace diferenciando un grupo de otro.Las variables de la dinámica interna que se tuvieron en cuenta fueron: autoridad, comunicación, afectividad y pautas de crianza. Además se indagó sobre la percepción que las familias tienen de la salud física y emocional de estos niños y niñas.

  12. Variable volume combustor

    Science.gov (United States)

    Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

    2017-01-17

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

  13. Collective variables and dissipation

    International Nuclear Information System (INIS)

    Balian, R.

    1984-09-01

    This is an introduction to some basic concepts of non-equilibrium statistical mechanics. We emphasize in particular the relevant entropy relative to a given set of collective variables, the meaning of the projection method in the Liouville space, its use to establish the generalized transport equations for these variables, and the interpretation of dissipation in the framework of information theory

  14. Variability: A Pernicious Hypothesis.

    Science.gov (United States)

    Noddings, Nel

    1992-01-01

    The hypothesis of greater male variability in test results is discussed in its historical context, and reasons feminists have objected to the hypothesis are considered. The hypothesis acquires political importance if it is considered that variability results from biological, rather than cultural, differences. (SLD)

  15. Reinforcing Saccadic Amplitude Variability

    Science.gov (United States)

    Paeye, Celine; Madelain, Laurent

    2011-01-01

    Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we…

  16. POVMs and hidden variables

    International Nuclear Information System (INIS)

    Stairs, Allen

    2007-01-01

    Recent results by Paul Busch and Adan Cabello claim to show that by appealing to POVMs, non-contextual hidden variables can be ruled out in two dimensions. While the results of Busch and Cabello are mathematically correct, interpretive problems render them problematic as no hidden variable proofs

  17. Interdependence Among Organizational Variables

    Science.gov (United States)

    Knowles, M. C.

    1975-01-01

    The interrelationship between a set of organizational variables was investigated at 14 work organizations within a company. The variables were production, quality, costs, job satisfaction of operatives, job satisfaction of supervisors, work anxiety, accidents, absence, labor turnover, and industrial unrest. (Author)

  18. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  19. Eternity Variables to Simulate Specifications

    NARCIS (Netherlands)

    Hesselink, WH; Boiten, EA; Moller, B

    2002-01-01

    Simulation of specifications is introduced as a unification and generalization of refinement mappings, history variables, forward simulations, prophecy variables, and backward simulations. Eternity variables are introduced as a more powerful alternative for prophecy variables and backward

  20. Relaciones entre los hongos filamentosos y solubilizadores de fosfatos con algunas variables edáficas y el manejo de cafetales

    Directory of Open Access Journals (Sweden)

    Raúl Hernando Posada

    2012-09-01

    Full Text Available El suelo y sus propiedades tienen múltiples relaciones con las comunidades fúngicas. El efecto conjunto de la intensidad de manejo y las variables edáficas, incluida la estabilidad de agregados sobre las comunidades de hongos microscópicos filamentosos (HMF, solubilizadores de fosfato de hierro (HSP-Fe y solubilizadores tanto de fosfato de hierro como de calcio (HSP-(Fe+Ca no han sido evaluadas en campo. A partir de 40 muestras edáficas de ocho plantaciones de café de Colombia y México, con diferentes intensidades de manejo (IMPC y con diferencias en sus variables edáficas, se aislaron y evaluaron las comunidades de HMF, HSP-Fe y HSP-(Fe+Ca durante 2008-2009. Empleando modelos basados en ecuaciones estructurales se encontró que el carbono orgánico se relacionó positivamente con la riqueza y abundancia de HMF (λ>0.58 y fue variable en su relación con HSP-Fe y HSP-(Fe+Ca. Las relaciones del fósforo disponible, pH y las fracciones de macro-agregados fueron altamente variables. El IMPC se relacionó negativamente con HSP-Fe (λ≤-0.21 en cafetales colombianos. Se discuten las interacciones para cada conjunto de variables (químicas, estabilidad de macro-agregados y de manejo de plantación y se explican las relaciones resultantes. Las relaciones de cada variable son inseparables del contexto edáfico y geográfico, los cuales imprimen marcadas diferencias.

  1. Variable Attitude Test Stand

    Data.gov (United States)

    Federal Laboratory Consortium — The Variable Attitude Test Stand designed and built for testing of the V-22 tilt rotor aircraft propulsion system, is used to evaluate the effect of aircraft flight...

  2. Several complex variables

    International Nuclear Information System (INIS)

    Field, M.J.

    1976-01-01

    Topics discussed include the elementary of holomorphic functions of several complex variables; the Weierstrass preparation theorem; meromorphic functions, holomorphic line bundles and divisors; elliptic operators on compact manifolds; hermitian connections; the Hodge decomposition theorem. ( author)

  3. Variable-Rate Premiums

    Data.gov (United States)

    Pension Benefit Guaranty Corporation — These interest rates are used to value vested benefits for variable rate premium purposes as described in PBGC's regulation on Premium Rates (29 CFR Part 4006) and...

  4. Variable Pricing Feasibility Assessment

    National Research Council Canada - National Science Library

    2004-01-01

    ...) and Willard Bishop Consulting (Barrington, IL) to evaluate the practicality of using a variable pricing system within DeCA to maintain an average of 30 percent customer savings and lower appropriated fund costs...

  5. Evolution of variable stars

    International Nuclear Information System (INIS)

    Becker, S.A.

    1986-08-01

    Throughout the domain of the H R diagram lie groupings of stars whose luminosity varies with time. These variable stars can be classified based on their observed properties into distinct types such as β Cephei stars, δ Cephei stars, and Miras, as well as many other categories. The underlying mechanism for the variability is generally felt to be due to four different causes: geometric effects, rotation, eruptive processes, and pulsation. In this review the focus will be on pulsation variables and how the theory of stellar evolution can be used to explain how the various regions of variability on the H R diagram are populated. To this end a generalized discussion of the evolutionary behavior of a massive star, an intermediate mass star, and a low mass star will be presented. 19 refs., 1 fig., 1 tab

  6. Calculus of one variable

    CERN Document Server

    Grossman, Stanley I

    1986-01-01

    Calculus of One Variable, Second Edition presents the essential topics in the study of the techniques and theorems of calculus.The book provides a comprehensive introduction to calculus. It contains examples, exercises, the history and development of calculus, and various applications. Some of the topics discussed in the text include the concept of limits, one-variable theory, the derivatives of all six trigonometric functions, exponential and logarithmic functions, and infinite series.This textbook is intended for use by college students.

  7. Software Testing Requires Variability

    DEFF Research Database (Denmark)

    Christensen, Henrik Bærbak

    2003-01-01

    Software variability is the ability of a software system or artefact to be changed, customized or configured for use in a particular context. Variability in software systems is important from a number of perspectives. Some perspectives rightly receive much attention due to their direct economic...... impact in software production. As is also apparent from the call for papers these perspectives focus on qualities such as reuse, adaptability, and maintainability....

  8. Suspended graphene variable capacitor

    OpenAIRE

    AbdelGhany, M.; Mahvash, F.; Mukhopadhyay, M.; Favron, A.; Martel, R.; Siaj, M.; Szkopek, T.

    2016-01-01

    The tuning of electrical circuit resonance with a variable capacitor, or varactor, finds wide application with the most important being wireless telecommunication. We demonstrate an electromechanical graphene varactor, a variable capacitor wherein the capacitance is tuned by voltage controlled deflection of a dense array of suspended graphene membranes. The low flexural rigidity of graphene monolayers is exploited to achieve low actuation voltage in an ultra-thin structure. Large arrays compr...

  9. Pulsating red variables

    International Nuclear Information System (INIS)

    Whitelock, P.A.

    1990-01-01

    The observational characteristics of pulsating red variables are reviewed with particular emphasis on the Miras. These variables represent the last stage in the evolution of stars on the Asymptotic Giant Branch (AGB). A large fraction of the IRAS sources in the Bulge are Mira variables and a subset of these are also OH/IR sources. Their periods range up to 720 days, though most are between 360 and 560 days. At a given period those stars with the highest pulsation amplitudes have the highest mass-loss rates; this is interpreted as evidence for a causal connection between mass-loss and pulsation. It is suggested that once an AGB star has become a Mira it will evolve with increasing pulsation amplitude and mass-loss, but with very little change of luminosity or logarithmic period. 26 refs

  10. Variable stator radial turbine

    Science.gov (United States)

    Rogo, C.; Hajek, T.; Chen, A. G.

    1984-01-01

    A radial turbine stage with a variable area nozzle was investigated. A high work capacity turbine design with a known high performance base was modified to accept a fixed vane stagger angle moveable sidewall nozzle. The nozzle area was varied by moving the forward and rearward sidewalls. Diffusing and accelerating rotor inlet ramps were evaluated in combinations with hub and shroud rotor exit rings. Performance of contoured sidewalls and the location of the sidewall split line with respect to the rotor inlet was compared to the baseline. Performance and rotor exit survey data are presented for 31 different geometries. Detail survey data at the nozzle exit are given in contour plot format for five configurations. A data base is provided for a variable geometry concept that is a viable alternative to the more common pivoted vane variable geometry radial turbine.

  11. Internal variables in thermoelasticity

    CERN Document Server

    Berezovski, Arkadi

    2017-01-01

    This book describes an effective method for modeling advanced materials like polymers, composite materials and biomaterials, which are, as a rule, inhomogeneous. The thermoelastic theory with internal variables presented here provides a general framework for predicting a material’s reaction to external loading. The basic physical principles provide the primary theoretical information, including the evolution equations of the internal variables. The cornerstones of this framework are the material representation of continuum mechanics, a weak nonlocality, a non-zero extra entropy flux, and a consecutive employment of the dissipation inequality. Examples of thermoelastic phenomena are provided, accompanied by detailed procedures demonstrating how to simulate them.

  12. Resiliencia y variables sociodemograficas

    OpenAIRE

    Calero Martinez, Edgar David

    2015-01-01

    En el presente trabajo se aborda la definición de una de las variables dentro de lo que se denomina Capital psicológico positivo, la Resiliencia, sus principales características y algunas de las variables socio demográficas que en el estudio pretenden ver el nivel de relación existente entre cada una de ellas (indirecta o directamente) en el proceso resiliente de una persona para posteriores discusiones y su implicación dentro de la gestión empresarial y sus direcciones futuras.

  13. Resiliencia en mujeres viudas por el conflicto armado vinculadas Funvida en Tumaco

    OpenAIRE

    Castillo Tenorio, Amanda; Palma Bernal, Edwin

    2016-01-01

    En esta investigación se analizará, a través del método cualitativo, la expansión de los comportamientos resilientes y la influencia de la Fundación de Mujeres Viudas por el Conflicto Armado (FUNVIDA)1 en la sociedad. El conflicto armado colombiano, sin lugar a dudas, ha causado un profundo traumatismo social, ha generado un inmenso rechazo y un dolor infinito en algunos hogares. Quizás, las muertes violentas perpetradas por estos grupos ilegales es el hecho más acuciante. Much...

  14. BALANCED SCORECARD: ESTRATÉGIA DE GESTÃO VINCULADA À MELHORIA DA QUALIDADE ORGANIZACIONAL

    Directory of Open Access Journals (Sweden)

    Juliana Andréia Rüdell Boligon

    2014-09-01

    Full Text Available As decisões gerenciais têm sido fortemente marcadas pela necessidade de aplicação de novas técnicas e ferramentas de gestão. Nesse sentido, o Balanced Scorecard (BSC, inicialmente concebido como um sistema de avaliação organizacional e, posteriormente, tido como uma metodologia de gestão estratégica é uma sistemática de gestão capaz de concentrar energia e recursos da organização no que é essencial - seu sucesso na criação de valor. Dessa forma, este artigo propõe-se a analisar de que forma o BSC, como sistemática de gestão, pode servir de ferramenta para apoio ao desdobramento das estratégias organizacionais e contribuir para a melhoria contínua da qualidade organizacional. Para a coleta das informações, empregou-se a observação simples e entrevista pré-estruturada aplicada à gerência da organização em estudo. Diante do aporte dessas informações, propôs-se uma metodologia de implantação do BSC na organização através do cumprimento de três estágios: conhecer e interpretar a missão, a visão e a estratégia da empresa; levantamento e estruturação dos indicadores estratégicos e, efetivação da estrutura de indicadores estratégicos. Como resultados, obteve-se o conhecimento de quais são os principais benefícios auferidos com o BSC, bem como alguns pontos críticos sendo o BSC uma possibilidade de alinhar estratégia, processos e pessoas em busca de um objetivo comum.

  15. Eugenia vinculada a aspectos bioéticos: uma revisão integrativa

    Directory of Open Access Journals (Sweden)

    Vanessa Cruz Santos

    Full Text Available O objetivo do estudo é analisar o que versam as produções científicas sobre eugenia, vinculando-as com aspectos bioéticos. Trata-se de uma revisão integrativa de literatura. Os dados foram coletados nas bases de dados Lilacs e SciELO, por meio dos descritores: eugenia, etnia e saúde, ética e bioética. Para a análise e posterior síntese dos artigos foi utilizada figura sinóptica. Verificou-se que a eugenia viola os direitos humanos, contradiz com o princípio da solidariedade e coloca em risco a diversidade humana. Conclui-se que houve déficit de artigos que abordem aspectos bioéticos vinculados à eugenia, assim, este estudo poderá contribuir para a reflexão sobre essa articulação.

  16. Prevalencia de fracturas faciales vinculadas con el deporte Prevalence of facial fractures linked to sports practice

    Directory of Open Access Journals (Sweden)

    José Manuel Díaz Fernández

    2004-08-01

    Full Text Available Se realizó una investigación descriptiva y transversal en 57 pacientes con fracturas faciales adquiridas durante la actividad deportiva, los cuales fueron atendidos en el Servicio de Cirugía Maxilofacial del Hospital Provincial "Saturnino Lora" de Santiago de Cuba, en el quinquenio 1992-1996. Este tipo de lesión representó el 6,2 % del total de tratadas en dicho período. En los atletas que jugaban con pelota y practicaban técnicas de combate hubo la mayor prevalencia de estas lesiones, fundamentalmente en los deportes de pelota, boxeo, baloncesto, karate y softbol. El impacto contra otro atleta fue el mecanismo de lesión más frecuente, sobre todo en los grupos de combate y juegos con pelota. Las fracturas de mandíbula dentoalveolares y cigomáticas resultaron ser los patrones de fracturas preponderantes. La conducta terapéutica en estos pacientes no difirió sustancialmente de la aplicada en aquellos con lesiones producidas por otras causas. La restricción de la actividad atlética osciló entre 9 y 15 semanas después del tratamiento inicial. En los atletas de alto rendimiento lesionados se impone establecer las estandarizaciones en su proceso rehabilitador para la toma de decisiones con respecto a su incorporación, tanto a la práctica como a la competencia, lo cual es fundamental en este sentido.A descriptive cross-sectional research study was made on 57 patients with facial fractures suffered during sporting activities. These patients had been seen by the Maxillofacial Surgery Service of "Saturnino Lara" provincial hospital in Santiago de Cuba from 1992 to 1996 and this type of lesions represented 6.2% of the fractures treated in this period of time. These lesions were more prevailing in athletes who mainly played ball sports, boxing, basketball, karate and softball. The collision with another sportsman was the most frequent injure mechanism fundamentally fight and ball sports. Dentoalveolar and zygomatic mandibular fractures were the predominant fracture patterns. Therapeutical procedures applied to these patients did not differ significantly from that followed in other types of lesions. Sports practicing interruption ranged from 9 to 15 weeks after the initial treatment. Regarding high performance athletes that get injured, it is necessary to set standards for their rehabilitation process to help in taking decisions as to their re-incorporation to sports practice and competition.

  17. Biological Sampling Variability Study

    Energy Technology Data Exchange (ETDEWEB)

    Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hutchison, Janine R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-11-08

    There are many sources of variability that exist in the sample collection and analysis process. This paper addresses many, but not all, sources of variability. The main focus of this paper was to better understand and estimate variability due to differences between samplers. Variability between days was also studied, as well as random variability within each sampler. Experiments were performed using multiple surface materials (ceramic and stainless steel), multiple contaminant concentrations (10 spores and 100 spores), and with and without the presence of interfering material. All testing was done with sponge sticks using 10-inch by 10-inch coupons. Bacillus atrophaeus was used as the BA surrogate. Spores were deposited using wet deposition. Grime was coated on the coupons which were planned to include the interfering material (Section 3.3). Samples were prepared and analyzed at PNNL using CDC protocol (Section 3.4) and then cultured and counted. Five samplers were trained so that samples were taken using the same protocol. Each sampler randomly sampled eight coupons each day, four coupons with 10 spores deposited and four coupons with 100 spores deposited. Each day consisted of one material being tested. The clean samples (no interfering materials) were run first, followed by the dirty samples (coated with interfering material). There was a significant difference in recovery efficiency between the coupons with 10 spores deposited (mean of 48.9%) and those with 100 spores deposited (mean of 59.8%). There was no general significant difference between the clean and dirty (containing interfering material) coupons or between the two surface materials; however, there was a significant interaction between concentration amount and presence of interfering material. The recovery efficiency was close to the same for coupons with 10 spores deposited, but for the coupons with 100 spores deposited, the recovery efficiency for the dirty samples was significantly larger (65

  18. Hacia una memorización de los signos de los impactos cruzados entre variables estratégicas

    Directory of Open Access Journals (Sweden)

    Ali Smida

    2010-04-01

    Full Text Available A la expresión “todo lo demás permanece constante” (del latín “ceteris paribus”, apreciada por los economistas, los seguidores de la prospectiva oponen la expresión “todo lo demás está cambiando”. Razón por la cual han desarrollado herramientas, en particular los escenarios y las matrices de impactos cruzados, que han puesto a disposición de la estrategia. Los escenarios han tenido un gran éxito en este campo, pero las matrices de impactos cruzados han tenido problemas para ser adoptadas por los estrategas de la empresa. Una de las desventajas de estas matrices es que son “amnésicas” en cuanto a los signos negativos de los impactos causados o experimentados por los actores o las variables. Hay, en efecto, una pérdida de información una vez que se pasa a los impactos indirectos, en la medida que el producto de un número par de signos negativos produce un signo positivo: en consecuencia las oposiciones son ocultadas. Este artículo propone un método que permite encontrar el rastro de los impactos negativos a lo largo de una cadena de acciones y reacciones. Para lo cual se realiza, a manera de ilustración, el estudio de los impactos positivos y negativos entre las variables estratégicas vinculadas al financiamiento de los hogares para los adultos mayores dependientes en Francia (EHPAD, por su sigla en idioma francés. En efecto, los impactos introducidos por la adhesión y la oposición de los protagonistas a la inclusión de los medicamentos en el precio de un programa integral de cuidados han producido una avalancha de textos legislativos y reglamentarios contradictorios que pueden llegar a comprometer el futuro de los EHPAD.

  19. INTER-EXAMINER VARIABILITY

    African Journals Online (AJOL)

    Objective: To establish whether inter-examiner variability is still a significant factor for the undergraduate orthopaedic clinical ... D. The scores for each student were tabulated and the range, mean, and pass rate determined for each of the examiners. ... has not the heart to reject the man”, consistently gave higher scores (1).

  20. Several real variables

    CERN Document Server

    Kantorovitz, Shmuel

    2016-01-01

    This undergraduate textbook is based on lectures given by the author on the differential and integral calculus of functions of several real variables. The book has a modern approach and includes topics such as: •The p-norms on vector space and their equivalence •The Weierstrass and Stone-Weierstrass approximation theorems •The differential as a linear functional; Jacobians, Hessians, and Taylor's theorem in several variables •The Implicit Function Theorem for a system of equations, proved via Banach’s Fixed Point Theorem •Applications to Ordinary Differential Equations •Line integrals and an introduction to surface integrals This book features numerous examples, detailed proofs, as well as exercises at the end of sections. Many of the exercises have detailed solutions, making the book suitable for self-study. Several Real Variables will be useful for undergraduate students in mathematics who have completed first courses in linear algebra and analysis of one real variable.

  1. Variability in GPS sources

    NARCIS (Netherlands)

    Jauncey, DL; King, EA; Bignall, HE; Lovell, JEJ; Kedziora-Chudczer, L; Tzioumis, AK; Tingay, SJ; Macquart, JP; McCulloch, PM

    2003-01-01

    Flux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, similar to10%, vary. Their variability falls

  2. All Those Independent Variables.

    Science.gov (United States)

    Meacham, Merle L.

    This paper presents a case study of a sixth grade remedial math class which illustrates the thesis that only the "experimental attitude," not the "experimental method," is appropriate in the classroom. The thesis is based on the fact that too many independent variables exist in a classroom situation to allow precise measurement. The case study…

  3. Variable speed generators

    CERN Document Server

    Boldea, Ion

    2005-01-01

    With the deregulation of electrical energy production and distribution, says Boldea (Polytechnical Institute, Timisoara, Romania) producers are looking for ways to tailor their electricity for different markets. Variable-speed electric generators are serving that purpose, up to the 400 megavolt ampere unit size, in Japan since 1996 and Germany sinc

  4. Surfing wave climate variability

    Science.gov (United States)

    Espejo, Antonio; Losada, Iñigo J.; Méndez, Fernando J.

    2014-10-01

    International surfing destinations are highly dependent on specific combinations of wind-wave formation, thermal conditions and local bathymetry. Surf quality depends on a vast number of geophysical variables, and analyses of surf quality require the consideration of the seasonal, interannual and long-term variability of surf conditions on a global scale. A multivariable standardized index based on expert judgment is proposed for this purpose. This index makes it possible to analyze surf conditions objectively over a global domain. A summary of global surf resources based on a new index integrating existing wave, wind, tides and sea surface temperature databases is presented. According to general atmospheric circulation and swell propagation patterns, results show that west-facing low to middle-latitude coasts are more suitable for surfing, especially those in the Southern Hemisphere. Month-to-month analysis reveals strong seasonal variations in the occurrence of surfable events, enhancing the frequency of such events in the North Atlantic and the North Pacific. Interannual variability was investigated by comparing occurrence values with global and regional modes of low-frequency climate variability such as El Niño and the North Atlantic Oscillation, revealing their strong influence at both the global and the regional scale. Results of the long-term trends demonstrate an increase in the probability of surfable events on west-facing coasts around the world in recent years. The resulting maps provide useful information for surfers, the surf tourism industry and surf-related coastal planners and stakeholders.

  5. Tides and Decadal Variability

    Science.gov (United States)

    Ray, Richard D.

    2003-01-01

    This paper reviews the mechanisms by which oceanic tides and decadal variability in the oceans are connected. We distinguish between variability caused by tides and variability observed in the tides themselves. Both effects have been detected at some level. The most obvious connection with decadal timescales is through the 18.6-year precession of the moon's orbit plane. This precession gives rise to a small tide of the same period and to 18.6-year modulations in the phase and amplitudes of short-period tides. The 18.6-year "node tide" is very small, no more than 2 cm anywhere, and in sea level data it is dominated by the ocean's natural Variability. Some authors have naively attributed climate variations with periods near 19 years directly to the node tide, but the amplitude of the tide is too small for this mechanism to be operative. The more likely explanation (Loder and Garrett, JGR, 83, 1967-70, 1978) is that the 18.6-y modulations in short-period tides, especially h e principal tide M2, cause variations in ocean mixing, which is then observed in temperature and other climatic indicators. Tidally forced variability has also been proposed by some authors, either in response to occasional (and highly predictable) tidal extremes or as a nonlinear low-frequency oscillation caused by interactions between short-period tides. The former mechanism can produce only short-duration events hardly more significant than normal tidal ranges, but the latter mechanism can in principle induce low-frequency oscillations. The most recent proposal of this type is by Keeling and Whorf, who highlight the 1800-year spectral peak discovered by Bond et al. (1997). But the proposal appears contrived and should be considered, in the words of Munk et al. (2002), "as the most likely among unlikely candidates."

  6. SELECTIVIDAD DEL INSECTICIDA CARTAP EMPLEANDO BIOENSAYOS CON ORGANISMOS NO DESTINATARIOS

    OpenAIRE

    Iannacone, José; Universidad Nacional Federico Villarreal (Perú).; Alvariño, Lorena; Universidad Nacional Federico Villarreal (Perú).

    2016-01-01

    El objetivo de la presente investigación fue evaluar la ecotoxicidad del cartap (Bala® 50 PS) sobre ocho organismos animales no destinatarios: 1) Melanoides tuberculata (Müller, 1774) (Mollusca), 2) Emerita analoga (Stimpson, 1857) (Crustácea), 3) Chironomus calligraphus Goeldi, 1805 (Diptera), 4) Cyprinus carpio (Linné, 1758) (Osteichyties), 5) Eisenia foetida (Savigny, 1826) (Annelida), 6) Podisus nigrispinus (Dallas, 1851) (Hemiptera), 7) Trichogramma fuentesi Torre, 1980 (Hymenoptera) y 8...

  7. Variable Permanent Magnet Quadrupole

    International Nuclear Information System (INIS)

    Mihara, T.; Iwashita, Y.; Kyoto U.; Kumada, M.; NIRS, Chiba; Spencer, C.M.; SLAC

    2007-01-01

    A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments

  8. On Complex Random Variables

    Directory of Open Access Journals (Sweden)

    Anwer Khurshid

    2012-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE In this paper, it is shown that a complex multivariate random variable  is a complex multivariate normal random variable of dimensionality if and only if all nondegenerate complex linear combinations of  have a complex univariate normal distribution. The characteristic function of  has been derived, and simpler forms of some theorems have been given using this characterization theorem without assuming that the variance-covariance matrix of the vector  is Hermitian positive definite. Marginal distributions of  have been given. In addition, a complex multivariate t-distribution has been defined and the density derived. A characterization of the complex multivariate t-distribution is given. A few possible uses of this distribution have been suggested.

  9. Technological Capability's Predictor Variables

    Directory of Open Access Journals (Sweden)

    Fernanda Maciel Reichert

    2011-03-01

    Full Text Available The aim of this study was to identify the factors that influence in configuration of the technological capability of companies in sectors with medium-low technological intensity. To achieve the goal proposed in this article a survey was carried out. Based on the framework developed by Lall (1992 which classifies firms in basic, intermediate and advanced level of technological capability; it was found that the predominant technological capability is intermediate, with 83.7% of respondent companies (plastics companies in Brazil. It is believed that the main contribution of this study is the finding that the dependent variable named “Technological Capability” can be explained at a rate of 65% by six variables: development of new processes; selection of the best equipment supplier; sales of internally developed new technology to third parties; design and manufacture of equipment; study of the work methods and perform inventory control; and improvement of product quality.

  10. Variable Kernel Density Estimation

    OpenAIRE

    Terrell, George R.; Scott, David W.

    1992-01-01

    We investigate some of the possibilities for improvement of univariate and multivariate kernel density estimates by varying the window over the domain of estimation, pointwise and globally. Two general approaches are to vary the window width by the point of estimation and by point of the sample observation. The first possibility is shown to be of little efficacy in one variable. In particular, nearest-neighbor estimators in all versions perform poorly in one and two dimensions, but begin to b...

  11. TEC variability over Havana

    International Nuclear Information System (INIS)

    Lazo, B.; Alazo, K.; Rodriguez, M.; Calzadilla, A.

    2003-01-01

    The variability of total electron content (TEC) measured over Havana using ATS-6, SMS-1 and GOES-3 geosynchronous satellite signals has been investigated for low, middle and high solar activity periods from 1974 to 1982. The obtained results show that standard deviation is smooth during nighttime hours and maximum at noon or postnoon hours. Strong solar activity dependence of standard deviation with a maximum values during HSA has been found. (author)

  12. Short timescale variability in the faint sky variability survey

    NARCIS (Netherlands)

    Morales-Rueda, L.; Groot, P.J.; Augusteijn, T.; Nelemans, G.A.; Vreeswijk, P.M.; Besselaar, E.J.M. van den

    2006-01-01

    We present the V-band variability analysis of the Faint Sky Variability Survey (FSVS). The FSVS combines colour and time variability information, from timescales of 24 minutes to tens of days, down to V = 24. We find that �1% of all point sources are variable along the main sequence reaching �3.5%

  13. Articulatory variability in cluttering.

    Science.gov (United States)

    Hartinger, Mariam; Mooshammer, Christine

    2008-01-01

    In order to investigate the articulatory processes of the hasty and mumbled speech in cluttering, the kinematic variability was analysed by means of electromagnetic midsagittal articulography. In contrast to persons with stuttering, those with cluttering improve their intelligibility by concentrating on their speech task. Variability has always been an important criterion in comparable studies of stuttering and is discussed in terms of the stability of the speech motor system. The aim of the current study was to analyse the spatial and temporal variability in the speech of three persons with cluttering (PWC) and three control speakers. All participants were native speakers of German. The speech material consisted of repetitive CV syllables and loan words such as 'emotionalisieren', because PWC have the severest problems with long words with a complex syllable structure. The results showed a significantly higher coefficient of variation for PWC in loan word production, both in the temporal and in the spatial domain, whereas the means of displacements and durations did not differ between groups. These findings were discussed in terms of the effects of the linguistic complexity, since for the syllable repetition task, no significant differences between PWC and controls were found. Copyright 2008 S. Karger AG, Basel.

  14. About hidden influence of predictor variables: Suppressor and mediator variables

    Directory of Open Access Journals (Sweden)

    Milovanović Boško

    2013-01-01

    Full Text Available In this paper procedure for researching hidden influence of predictor variables in regression models and depicting suppressor variables and mediator variables is shown. It is also shown that detection of suppressor variables and mediator variables could provide refined information about the research problem. As an example for applying this procedure, relation between Atlantic atmospheric centers and air temperature and precipitation amount in Serbia is chosen. [Projekat Ministarstva nauke Republike Srbije, br. 47007

  15. Individual Movement Variability Magnitudes Are Explained by Cortical Neural Variability.

    Science.gov (United States)

    Haar, Shlomi; Donchin, Opher; Dinstein, Ilan

    2017-09-13

    Humans exhibit considerable motor variability even across trivial reaching movements. This variability can be separated into specific kinematic components such as extent and direction that are thought to be governed by distinct neural processes. Here, we report that individual subjects (males and females) exhibit different magnitudes of kinematic variability, which are consistent (within individual) across movements to different targets and regardless of which arm (right or left) was used to perform the movements. Simultaneous fMRI recordings revealed that the same subjects also exhibited different magnitudes of fMRI variability across movements in a variety of motor system areas. These fMRI variability magnitudes were also consistent across movements to different targets when performed with either arm. Cortical fMRI variability in the posterior-parietal cortex of individual subjects explained their movement-extent variability. This relationship was apparent only in posterior-parietal cortex and not in other motor system areas, thereby suggesting that individuals with more variable movement preparation exhibit larger kinematic variability. We therefore propose that neural and kinematic variability are reliable and interrelated individual characteristics that may predispose individual subjects to exhibit distinct motor capabilities. SIGNIFICANCE STATEMENT Neural activity and movement kinematics are remarkably variable. Although intertrial variability is rarely studied, here, we demonstrate that individual human subjects exhibit distinct magnitudes of neural and kinematic variability that are reproducible across movements to different targets and when performing these movements with either arm. Furthermore, when examining the relationship between cortical variability and movement variability, we find that cortical fMRI variability in parietal cortex of individual subjects explained their movement extent variability. This enabled us to explain why some subjects

  16. Understanding Solar Cycle Variability

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, R. H.; Schüssler, M., E-mail: cameron@mps.mpg.de [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2017-07-10

    The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of timescales. Most prominent is the 11-year solar cycle, which is significantly modulated on longer timescales. Drawing from dynamo theory, together with the empirical results of past solar activity and similar phenomena for solar-like stars, we show that the variability of the solar cycle can be essentially understood in terms of a weakly nonlinear limit cycle affected by random noise. In contrast to ad hoc “toy models” for the solar cycle, this leads to a generic normal-form model, whose parameters are all constrained by observations. The model reproduces the characteristics of the variable solar activity on timescales between decades and millennia, including the occurrence and statistics of extended periods of very low activity (grand minima). Comparison with results obtained with a Babcock–Leighton-type dynamo model confirm the validity of the normal-mode approach.

  17. EVALUACIÓN DE LA BIOTRANSFORMACIÓN DE GERANIOL Y (R-(+-α-PINENO EMPLEANDO CÉLULAS DE Rhodococcus opacus DSM 44313 EVALUATION OF THE BIOTRANSFORMATION OF GERANIOL AND (R-(+-α-PINENE USING CELL OF Rhodococcus opacus DSM 44313

    Directory of Open Access Journals (Sweden)

    JENNIFER PILAR ROJAS

    2009-12-01

    Full Text Available La alta biodisponibilidad de los monoterpenos los hace precursores promisorios en los procesos de biotransformación, mediante los que se producen compuestos de valor agregado que pueden considerarse naturales, debido a que se obtienen por métodos enzimáticos a partir de precursores aislados de la naturaleza. En el presente estudio se evaluó la biotransformación de geraniol y (R-(+-α-pineno empleando la cepa bacteriana Rhodococcus opacus DSM 44313, para ello se determinó la influencia del tiempo de crecimiento de la bacteria, tomando suspensiones celulares en la mitad y finalizando la fase exponencial. También se evaluaron tres tiempos de reacción (12, 24 y 48 h y el efecto de un cosolvente, agregando los sustratos puros y disueltos en etanol al 10%. A partir del geraniol se produjeron geranial, ácido geránico y 6-metil-5-hepten-2-ona, sólo cuando el sustrato se adicionó puro, y se formaron en mayor concentración cuando la bacteria estaba finalizando su fase de crecimiento exponencial. Con el (R-(+-α-pineno se produjo como compuesto principal el (R-(+-cis-verbenol, siendo mayor su concentración agregando el pineno disuelto en etanol, y cuando la bacteria se encontraba en la mitad de su fase de crecimiento exponencial. Los resultados indican que el comportamiento de la bacteria cambia según el sustrato adicionado, debido a las propiedades de cada monoterpeno, pero los compuestos obtenidos con ambos sustratos tienen importantes aplicaciones en las industrias farmacéutica, alimenticia y de perfumeríaThe high bioavailability of monoterpenes make them promising precursors in biotransformation processes, through which produce value-added compounds that can be considered natural because they are obtained by enzymatic methods from precursors isolated from nature. In the present study we evaluated the biotransformation of geraniol and (R-(+-α-pinene using a bacterial strain of Rhodococcus opacus DSM 44313; the influence of growth time

  18. Climate variability and change

    International Nuclear Information System (INIS)

    Manton, M.

    2006-01-01

    When Australia's climate should not be definite barrier to the population reaching 30 million by 2050, it is recognised that our climate has limited the development of the nation over the past 200 years. Indeed in 1911, based on a comparison of the climate and development between the US and Australia. Griffith Taylor predicted that Australia's population would be 19 million at the end of the 20th century, which is a pretty good 90-year forecast. The climate constraint is not only due to much of the country being semi-arid with an annual rainfall below 400 millimetres, but also due to the large year-to-year variability of rainfall across the country

  19. Variable cycle engine

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, A.P.; Sprunger, E.V.

    1980-09-16

    A variable cycle turboshaft engine includes a remote fan system and respective high and low pressure systems for selectively driving the fan system in such a manner as to provide VTOL takeoff capability and minimum specific fuel consumption (SFC) at cruise and loiter conditions. For takeoff the fan system is primarily driven by the relatively large low pressure system whose combustor receives the motive fluid from a core bypass duct and, for cruise and loiter conditions, the fan system is driven by both a relatively small high pressure core and the low pressure system with its combustor inoperative. A mixer is disposed downstream of the high pressure system for mixing the relatively cold air from the bypass duct and the relatively hot air from the core prior to its flow to the low pressure turbine.

  20. Statistical variability of hydro-meteorological variables as indicators ...

    African Journals Online (AJOL)

    Statistical variability of hydro-meteorological variables as indicators of climate change in north-east Sokoto-Rima basin, Nigeria. ... water resources development including water supply project, agriculture and tourism in the study area. Key word: Climate change, Climatic variability, Actual evapotranspiration, Global warming ...

  1. The Performance of Variable Annuities

    OpenAIRE

    Michael J. McNamara; Henry R. Oppenheimer

    1991-01-01

    Variable annuities have become increasingly important in retirement plans. This paper provides an examination of the investment performance of variable annuities for the period year-end 1973 to year-end 1988. Returns, risk, and selectivity measures are analyzed for the sample of annuities, for individual variable annuities, and for subsamples of annuities with similar portfolio size and turnover. While the investment returns of variable annuities were greater than inflation over the period, t...

  2. Strong Decomposition of Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jørgensen, Jørgen; Kagan, Abram M.; Pitt, Loren D.

    2007-01-01

    A random variable X is stongly decomposable if X=Y+Z where Y=Φ(X) and Z=X-Φ(X) are independent non-degenerated random variables (called the components). It is shown that at least one of the components is singular, and we derive a necessary and sufficient condition for strong decomposability...... of a discrete random variable....

  3. Preservice Teachers' Understanding of Variable

    Science.gov (United States)

    Brown, Sue; Bergman, Judy

    2013-01-01

    This study examines the research on middle school students' understanding of variables and explores preservice elementary and middle school teachers' knowledge of variables. According to research studies, middle school students have limited understanding of variables. Many studies have examined the performance of middle school students and offered…

  4. Variable angle correlation spectroscopy

    International Nuclear Information System (INIS)

    Lee, Y.K.; Lawrence Berkeley Lab., CA

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13 C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system

  5. Integration i flere variable

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    2010-01-01

    Denne note handler om parameterfremstillinger for kurver, flader og rumlige områder og om integration af funktioner på sådanne geometriske objekter. Formålet er primært at opstille og motivere de generelle definitioner og beregninger af henholdsvis kurve- \\, flade- \\, og rum-integraler. Udgangspu......Denne note handler om parameterfremstillinger for kurver, flader og rumlige områder og om integration af funktioner på sådanne geometriske objekter. Formålet er primært at opstille og motivere de generelle definitioner og beregninger af henholdsvis kurve- \\, flade- \\, og rum......-integralerne. Undervejs introduceres \\texttt{Integrator8}. Det er en pakke med Maple procedurer, som er udviklet specielt med henblik på eksempelbaseret visuel læring af de indledende integrationsbegreber og deres mangfoldige anvendelser. Vi giver eksempler på, hvordan integration i flere variable anvendes til beregning...... og forståelse af rumfang, vægt, massemidtpunkter, inertimomenter, kraftmomenter, etc. Flowkurverne for et givet vektorfelt i rummet kan findes og visualiseres med \\texttt{Integrator8}. De vigtige begreber divergens og rotation for et vektorfelt fremtræder derved som naturlige størrelser til...

  6. Climate variability and climate change

    International Nuclear Information System (INIS)

    Rind, D.

    1990-01-01

    Changes of variability with climate change are likely to have a substantial impact on vegetation and society, rivaling the importance of changes in the mean values themselves. A variety of paleoclimate and future climate simulations performed with the GISS global climate model is used to assess how the variabilities of temperature and precipitation are altered as climate warms or cools. In general, as climate warms, temperature variability decreases due to reductions in the latitudinal temperature gradient and precipitation variability increases together with the intensity of the hydrologic cycle. If future climate projections are accurate, the reduction in temperature variability will be minimized by the rapid change in mean temperatures, but the hydrologic variability will be amplified by increased evapotranspiration. Greater hydrologic variability would appear to pose a potentially severe problem for the next century

  7. Climate variability and climate change

    International Nuclear Information System (INIS)

    Rind, D.

    1991-01-01

    Changes of variability with climate change are likely to have a substantial impact on vegetation and society, rivaling the importance of changes in the mean values themselves. A variety of paleoclimate and future climate simulations performed with the GISS global climate model is used to assess how the variabilities of temperature and precipitation are altered as climate warms or cools. In general, as climate warms, temperature variability decreases due to reductions in the latitudinal temperature gradient and precipitation variability increases together with the intensity of the hydrologic cycle. If future climate projections are accurate, the reduction in temperature variability will be minimized by the rapid change in mean temperatures, but the hydrologic variability will be amplified by increased evapotranspiration. Greater hydrologic variability would appear to pose a potentially severe problem for the next century. 19 refs.; 3 figs.; 2 tabs

  8. Intraspecific chromosome variability

    Directory of Open Access Journals (Sweden)

    N Dubinin

    2010-12-01

    Full Text Available (Editorial preface. The publication is presented in order to remind us of one of dramatic pages of the history of genetics. It re-opens for the contemporary reader a comprehensive work marking the priority change from plant cytogenetics to animal cytogenetics led by wide population studies which were conducted on Drosophila polytene chromosomes. The year of the publication (1937 became the point of irretrievable branching between the directions of Old World and New World genetics connected with the problems of chromosome variability and its significance for the evolution of the species. The famous book of T. Dobzhansky (1937 was published by Columbia University in the US under the title “Genetics and the origin of species”, and in the shadow of this American ‘skybuilding’ all other works grew dim. It is remarkable that both Dobzhansky and Dubinin come to similar conclusions about the role of chromosomes in speciation. This is not surprising given that they both might be considered as representatives of the Russian genetic school, by their birth and education. Interestingly, Dobzhansky had never referred to the full paper of Dubinin et al. (1937, though a previous short communication in Nature (1936 was included together with all former papers on the related subject. In full, the volume of the original publication printed in the Biological Journal in Moscow comprised 47 pages, in that number 41 pages of the Russian text accompanied by 16 Figs, a table and reference list, and, above all, 6 pages of the English summary. This final part in English is now reproduced in the authors’ version with the only addition being the reference list in the originally printed form.

  9. Benchmarking Variable Selection in QSAR.

    Science.gov (United States)

    Eklund, Martin; Norinder, Ulf; Boyer, Scott; Carlsson, Lars

    2012-02-01

    Variable selection is important in QSAR modeling since it can improve model performance and transparency, as well as reduce the computational cost of model fitting and predictions. Which variable selection methods that perform well in QSAR settings is largely unknown. To address this question we, in a total of 1728 benchmarking experiments, rigorously investigated how eight variable selection methods affect the predictive performance and transparency of random forest models fitted to seven QSAR datasets covering different endpoints, descriptors sets, types of response variables, and number of chemical compounds. The results show that univariate variable selection methods are suboptimal and that the number of variables in the benchmarked datasets can be reduced with about 60 % without significant loss in model performance when using multivariate adaptive regression splines MARS and forward selection. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. HOW NORMAL IS VARIABLE, OR HOW VARIABLE IS NORMAL

    NARCIS (Netherlands)

    TOUWEN, BCL

    Variability is an important property of the central nervous system, and it shows characteristic changes during infancy and childhood. The large amount of variations in the performance of sensomotor functions in infancy is called indiscriminate or primary variability. During toddling age the child

  11. Photometric Variability in the Faint Sky Variability Survey

    NARCIS (Netherlands)

    Morales-Rueda, L.; Groot, P.J.; Augusteijn, T.; Nelemans, G.A.; Vreeswijk, P.M.; Besselaar, E.J.M. van den

    2005-01-01

    The Faint Sky Variability Survey (FSVS) is aimed at finding photometric and/or astrometric variable objects between 16th and 24th mag on time-scales between tens of minutes and years with photometric precisions ranging from 3 millimag to 0.2 mag. An area of ~23 deg2, located at mid and

  12. Soil variability in mountain areas

    OpenAIRE

    Zanini, E.; Freppaz, M.; Stanchi, S.; Bonifacio, E.; Egli, M.

    2015-01-01

    The high spatial variability of soils is a relevant issue at local and global scales, and determines the complexity of soil ecosystem functions and services. This variability derives from strong dependencies of soil ecosystems on parent materials, climate, relief and biosphere, including human impact. Although present in all environments, the interactions of soils with these forming factors are particularly striking in mountain areas.

  13. Speed control variable rate irrigation

    Science.gov (United States)

    Speed control variable rate irrigation (VRI) is used to address within field variability by controlling a moving sprinkler’s travel speed to vary the application depth. Changes in speed are commonly practiced over areas that slope, pond or where soil texture is predominantly different. Dynamic presc...

  14. Delta Scuti variables. Lecture 6

    International Nuclear Information System (INIS)

    Cox, A.N.

    1983-01-01

    The class of variables near or on the upper main sequence, the delta Scuti variables, are not only the usual ones about the masses, radii, and luminosities, but also the age, rotation, element diffusion to change the surface layer composition, the occurance of convection and the presence of radial and nonradial pulsation modes

  15. Variability in human body size

    Science.gov (United States)

    Annis, J. F.

    1978-01-01

    The range of variability found among homogeneous groups is described and illustrated. Those trends that show significantly marked differences between sexes and among a number of racial/ethnic groups are also presented. Causes of human-body size variability discussed include genetic endowment, aging, nutrition, protective garments, and occupation. The information is presented to aid design engineers of space flight hardware and equipment.

  16. THE VARIABILITY OF INTERLANGUAGE USE

    African Journals Online (AJOL)

    www

    Variability is evident in the interlanguage grammars of all L2 learners, irrespective of their levels of proficiency; their interlanguage use is characterised by the variable occurrence of target L2 forms, and the .... instruction and negative feedback to discover that their hypotheses about the L2 are incorrect. 4.1. Krashen's view.

  17. Independent SU(2)-loop variables

    International Nuclear Information System (INIS)

    Loll, R.

    1991-04-01

    We give a reduction procedure for SU(2)-trace variables and introduce a complete set of indepentent, gauge-invariant and almost local loop variables for the configuration space of SU(2)-lattice gauge theory in 2+1 dimensions. (orig.)

  18. Operant Variability: Procedures and Processes

    Science.gov (United States)

    Machado, Armando; Tonneau, Francois

    2012-01-01

    Barba's (2012) article deftly weaves three main themes in one argument about operant variability. From general theoretical considerations on operant behavior (Catania, 1973), Barba derives methodological guidelines about response differentiation and applies them to the study of operant variability. In the process, he uncovers unnoticed features of…

  19. Imaging Variable Stars with HST

    Science.gov (United States)

    Karovska, M.

    2012-06-01

    (Abstract only) The Hubble Space Telescope (HST) observations of astronomical sources, ranging from objects in our solar system to objects in the early Universe, have revolutionized our knowledge of the Universe its origins and contents. I highlight results from HST observations of variable stars obtained during the past twenty or so years. Multiwavelength observations of numerous variable stars and stellar systems were obtained using the superb HST imaging capabilities and its unprecedented angular resolution, especially in the UV and optical. The HST provided the first detailed images probing the structure of variable stars including their atmospheres and circumstellar environments. AAVSO observations and light curves have been critical for scheduling of many of these observations and provided important information and context for understanding of the imaging results of many variable sources. I describe the scientific results from the imaging observations of variable stars including AGBs, Miras, Cepheids, semiregular variables (including supergiants and giants), YSOs and interacting stellar systems with a variable stellar components. These results have led to an unprecedented understanding of the spatial and temporal characteristics of these objects and their place in the stellar evolutionary chains, and in the larger context of the dynamic evolving Universe.

  20. Low-Frequency Temporal Variability in Mira and Semiregular Variables

    Science.gov (United States)

    Templeton, Matthew R.; Karovska, M.; Waagen, E. O.

    2012-01-01

    We investigate low-frequency variability in a large sample of Mira and semiregular variables with long-term visual light curves from the AAVSO International Database. Our aim is to determine whether we can detect and measure long-timescale variable phenomena in these stars, for example photometric variations that might be associated with supergranular convection. We analyzed the long-term light curves of 522 variable stars of the Mira and SRa, b, c, and d classes. We calculated their low-frequency time-series spectra to characterize rednoise with the power density spectrum index, and then correlate this index with other observable characteristics such as spectral type and primary pulsation period. In our initial analysis of the sample, we see that the semiregular variables have a much broader range of spectral index than the Mira types, with the SRb subtype having the broadest range. Among Mira variables we see that the M- and S-type Miras have similarly wide ranges of index, while the C-types have the narrowest with generally shallower slopes. There is also a trend of steeper slope with larger amplitude, but at a given amplitude, a wide range of slopes are seen. The ultimate goal of the project is to identify stars with strong intrinsic red noise components as possible targets for resolved surface imaging with interferometry.

  1. Longitudinal Research with Latent Variables

    CERN Document Server

    van Montfort, Kees; Satorra, Albert

    2010-01-01

    This book combines longitudinal research and latent variable research, i.e. it explains how longitudinal studies with objectives formulated in terms of latent variables should be carried out, with an emphasis on detailing how the methods are applied. Because longitudinal research with latent variables currently utilizes different approaches with different histories, different types of research questions, and different computer programs to perform the analysis, the book is divided into nine chapters. Starting from some background information about the specific approach, short history and the ma

  2. Manipulating continuous variable photonic entanglement

    International Nuclear Information System (INIS)

    Plenio, M.B.

    2005-01-01

    I will review our work on photonic entanglement in the continuous variable regime including both Gaussian and non-Gaussian states. The feasibility and efficiency of various entanglement purification protocols are discussed this context. (author)

  3. Intensive variable and its application

    CERN Document Server

    Zheng, Xinqi; Yuan, Zhiyuan

    2014-01-01

    Opening with intensive variables theory, using a combination of static and dynamic GIS and integrating numerical calculation and spatial optimization, this book creates a framework and methodology for evaluating land use effect, among other concepts.

  4. Variability of nitrate and phosphate

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; Sundar, D.

    Nitrate and phosphate are important elements of the biogeochemical system of an estuary. Observations carried out during the dry season April-May 2002, and March 2003 and wet season September 2002, show temporal and spatial variability of these two...

  5. Solar Variability and Planetary Climates

    CERN Document Server

    Calisesi, Y; Gray, L; Langen, J; Lockwood, M

    2007-01-01

    Variations in solar activity, as revealed by variations in the number of sunspots, have been observed since ancient times. To what extent changes in the solar output may affect planetary climates, though, remains today more than ever a subject of controversy. In 2000, the SSSI volume on Solar Variability and Climate reviewed the to-date understanding of the physics of solar variability and of the associated climate response. The present volume on Solar Variability and Planetary Climates provides an overview of recent advances in this field, with particular focus at the Earth's middle and lower atmosphere. The book structure mirrors that of the ISSI workshop held in Bern in June 2005, the collection of invited workshop contributions and of complementary introductory papers synthesizing the current understanding in key research areas such as middle atmospheric processes, stratosphere-troposphere dynamical coupling, tropospheric aerosols chemistry, solar storm influences, solar variability physics, and terrestri...

  6. Decomposing global crop yield variability

    Science.gov (United States)

    Ben-Ari, Tamara; Makowski, David

    2014-11-01

    Recent food crises have highlighted the need to better understand the between-year variability of agricultural production. Although increasing future production seems necessary, the globalization of commodity markets suggests that the food system would also benefit from enhanced supplies stability through a reduction in the year-to-year variability. Here, we develop an analytical expression decomposing global crop yield interannual variability into three informative components that quantify how evenly are croplands distributed in the world, the proportion of cultivated areas allocated to regions of above or below average variability and the covariation between yields in distinct world regions. This decomposition is used to identify drivers of interannual yield variations for four major crops (i.e., maize, rice, soybean and wheat) over the period 1961-2012. We show that maize production is fairly spread but marked by one prominent region with high levels of crop yield interannual variability (which encompasses the North American corn belt in the USA, and Canada). In contrast, global rice yields have a small variability because, although spatially concentrated, much of the production is located in regions of below-average variability (i.e., South, Eastern and South Eastern Asia). Because of these contrasted land use allocations, an even cultivated land distribution across regions would reduce global maize yield variance, but increase the variance of global yield rice. Intermediate results are obtained for soybean and wheat for which croplands are mainly located in regions with close-to-average variability. At the scale of large world regions, we find that covariances of regional yields have a negligible contribution to global yield variance. The proposed decomposition could be applied at any spatial and time scales, including the yearly time step. By addressing global crop production stability (or lack thereof) our results contribute to the understanding of a key

  7. Flow variability and hillslope hydrology

    Energy Technology Data Exchange (ETDEWEB)

    Huff, D D; O' Neill, R V; Emanuel, W R; Elwood, J W; Newbold, J D

    1982-01-01

    Examination of spatial variability of streamflow in headwater areas can provide important insight about factors that influence hillslope hydrology. Detailed observations of variations in stream channel input, based on a tracer experiment, indicate that topography alone cannot explain flow variability. However, determination of changes in channel input on a small spatial scale can provide valuable clues to factors, such as structural geology that control subsurface flows.

  8. Ordering variable for parton showers

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, Zoltan [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Soper, Davison E. [Oregon Univ., Eugene, OR (United States). Inst. of Theoretical Science

    2014-01-15

    The parton splittings in a parton shower are ordered according to an ordering variable, for example the transverse momentum of the daughter partons relative to the direction of the mother, the virtuality of the splitting, or the angle between the daughter partons. We analyze the choice of the ordering variable and conclude that one particular choice has the advantage of factoring softer splittings from harder splittings graph by graph in a physical gauge.

  9. Ordering variable for parton showers

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, Zoltán [DESY,Notkestrasse 85, 22607 Hamburg (Germany); Soper, Davison E. [Institute of Theoretical Science, University of Oregon,Eugene, OR 97403-5203 (United States)

    2014-06-30

    The parton splittings in a parton shower are ordered according to an ordering variable, for example the transverse momentum of the daughter partons relative to the direction of the mother, the virtuality of the splitting, or the angle between the daughter partons. We analyze the choice of the ordering variable and conclude that one particular choice has the advantage of factoring softer splittings from harder splittings graph by graph in a physical gauge.

  10. Variable stars in the classroom

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Bajo, F [Departamento de Electronica e IngenierIa Electromecanica, Escuela de IngenierIas Industriales, Universidad de Extremadura, Avda de Elvas s/n, 06071 Badajoz (Spain); Vaquero, J M [Departamento de Fisica, Escuela Politecnica, Universidad de Extremadura, Avda de la Universidad s/n, 10071 Caceres (Spain)

    2006-05-01

    Variable stars offer interesting possibilities from the point of view of educational applications, from the experimental collection of data to analysis to obtain physical information. In this paper, brightness measurements of two periodic variable stars easily accessible with small telescopes are presented and analysed. This practical experiment is highly appropriate for educational use in undergraduate physics and astrophysics laboratories and allows students to approximate scientific research.

  11. Variable stars in the classroom

    International Nuclear Information System (INIS)

    Sanchez-Bajo, F; Vaquero, J M

    2006-01-01

    Variable stars offer interesting possibilities from the point of view of educational applications, from the experimental collection of data to analysis to obtain physical information. In this paper, brightness measurements of two periodic variable stars easily accessible with small telescopes are presented and analysed. This practical experiment is highly appropriate for educational use in undergraduate physics and astrophysics laboratories and allows students to approximate scientific research

  12. Ordering variable for parton showers

    International Nuclear Information System (INIS)

    Nagy, Zoltan; Soper, Davison E.

    2014-01-01

    The parton splittings in a parton shower are ordered according to an ordering variable, for example the transverse momentum of the daughter partons relative to the direction of the mother, the virtuality of the splitting, or the angle between the daughter partons. We analyze the choice of the ordering variable and conclude that one particular choice has the advantage of factoring softer splittings from harder splittings graph by graph in a physical gauge.

  13. Investigation of load reduction for a variable speed, variable pitch, and variable coning wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, K. [Univ. of Utah, Salt Lake City, UT (United States)

    1997-12-31

    A two bladed, variable speed and variable pitch wind turbine was modeled using ADAMS{reg_sign} to evaluate load reduction abilities of a variable coning configuration as compared to a teetered rotor, and also to evaluate control methods. The basic dynamic behavior of the variable coning turbine was investigated and compared to the teetered rotor under constant wind conditions as well as turbulent wind conditions. Results indicate the variable coning rotor has larger flap oscillation amplitudes and much lower root flap bending moments than the teetered rotor. Three methods of control were evaluated for turbulent wind simulations. These were a standard IPD control method, a generalized predictive control method, and a bias estimate control method. Each control method was evaluated for both the variable coning configuration and the teetered configuration. The ability of the different control methods to maintain the rotor speed near the desired set point is evaluated from the RMS error of rotor speed. The activity of the control system is evaluated from cycles per second of the blade pitch angle. All three of the methods were found to produce similar results for the variable coning rotor and the teetered rotor, as well as similar results to each other.

  14. Variable Selection via Partial Correlation.

    Science.gov (United States)

    Li, Runze; Liu, Jingyuan; Lou, Lejia

    2017-07-01

    Partial correlation based variable selection method was proposed for normal linear regression models by Bühlmann, Kalisch and Maathuis (2010) as a comparable alternative method to regularization methods for variable selection. This paper addresses two important issues related to partial correlation based variable selection method: (a) whether this method is sensitive to normality assumption, and (b) whether this method is valid when the dimension of predictor increases in an exponential rate of the sample size. To address issue (a), we systematically study this method for elliptical linear regression models. Our finding indicates that the original proposal may lead to inferior performance when the marginal kurtosis of predictor is not close to that of normal distribution. Our simulation results further confirm this finding. To ensure the superior performance of partial correlation based variable selection procedure, we propose a thresholded partial correlation (TPC) approach to select significant variables in linear regression models. We establish the selection consistency of the TPC in the presence of ultrahigh dimensional predictors. Since the TPC procedure includes the original proposal as a special case, our theoretical results address the issue (b) directly. As a by-product, the sure screening property of the first step of TPC was obtained. The numerical examples also illustrate that the TPC is competitively comparable to the commonly-used regularization methods for variable selection.

  15. All varieties of encoding variability are not created equal: Separating variable processing from variable tasks

    Science.gov (United States)

    Huff, Mark J.; Bodner, Glen E.

    2014-01-01

    Whether encoding variability facilitates memory is shown to depend on whether item-specific and relational processing are both performed across study blocks, and whether study items are weakly versus strongly related. Variable-processing groups studied a word list once using an item-specific task and once using a relational task. Variable-task groups’ two different study tasks recruited the same type of processing each block. Repeated-task groups performed the same study task each block. Recall and recognition were greatest in the variable-processing group, but only with weakly related lists. A variable-processing benefit was also found when task-based processing and list-type processing were complementary (e.g., item-specific processing of a related list) rather than redundant (e.g., relational processing of a related list). That performing both item-specific and relational processing across trials, or within a trial, yields encoding-variability benefits may help reconcile decades of contradictory findings in this area. PMID:25018583

  16. Entropy as a collective variable

    Science.gov (United States)

    Parrinello, Michele

    Sampling complex free energy surfaces that exhibit long lived metastable states separated by kinetic bottlenecks is one of the most pressing issues in the atomistic simulations of matter. Not surprisingly many solutions to this problem have been suggested. Many of them are based on the identification of appropriate collective variables that span the manifold of the slow varying modes of the system. While much effort has been put in devising and even constructing on the fly appropriate collective variables there is still a cogent need of introducing simple, generic, physically transparent, and yet effective collective variables. Motivated by the physical observation that in many case transitions between one metastable state and another result from a trade off between enthalpy and entropy we introduce appropriate collective variables that are able to represent in a simple way these two physical properties. We use these variables in the context of the recently introduced variationally enhanced sampling and apply it them with success to the simulation of crystallization from the liquid and to conformational transitions in protein. Department of Chemistry and Applied Biosciences, ETH Zurich, and Facolta' di Informatica, Istituto di Scienze Computazionali, Universita' della Svizzera Italiana, Via G. Buffi 13, 6900 Lugano, Switzerland.

  17. Variable sensory perception in autism.

    Science.gov (United States)

    Haigh, Sarah M

    2018-03-01

    Autism is associated with sensory and cognitive abnormalities. Individuals with autism generally show normal or superior early sensory processing abilities compared to healthy controls, but deficits in complex sensory processing. In the current opinion paper, it will be argued that sensory abnormalities impact cognition by limiting the amount of signal that can be used to interpret and interact with environment. There is a growing body of literature showing that individuals with autism exhibit greater trial-to-trial variability in behavioural and cortical sensory responses. If multiple sensory signals that are highly variable are added together to process more complex sensory stimuli, then this might destabilise later perception and impair cognition. Methods to improve sensory processing have shown improvements in more general cognition. Studies that specifically investigate differences in sensory trial-to-trial variability in autism, and the potential changes in variability before and after treatment, could ascertain if trial-to-trial variability is a good mechanism to target for treatment in autism. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  18. Cataclysmic variables, Hubble-Sandage variables and eta Carinae

    International Nuclear Information System (INIS)

    Bath, G.T.

    1980-01-01

    The Hubble-Sandage variables are the most luminous stars in external galaxies. They were first investigated by Hubble and Sandage (1953) for use as distance indicators. Their main characteristics are high luminosity, blue colour indices, and irregular variability. Spectroscopically they show hydrogen and helium in emission with occasionally weaker FeII and [FeII], and no Balmer jump (Humphreys 1975, 1978). In this respect they closely resemble cataclysmic variables, particularly dwarf novae. In the quiescent state dwarf novae show broad H and HeI, together with a strong UV continuum. In contrast to the spectroscopic similarities, the luminosities could hardly differ more. Rather than being the brightest stars known, quiescent dwarf novae are as faint or fainter than the sun. It is suggested that the close correspondence between the spectral appearance of the two classes combined with the difference in luminosity is well accounted for by a model of Hubble-Sandage variables in which the same physical processes are occurring, but on a larger scale. (Auth.)

  19. Observations of fast variable objects

    International Nuclear Information System (INIS)

    Alekseev, G.N.

    1978-01-01

    A problem on studying fast variable astronomic objects is considered. The basis of the method used in the experiment is a detailed photoelectric study of a fast variableness along with spectroscopy of a high time resolution. Power spectrum of the SS Cyg brightness oscillations and autocorrelation function of the AX Mon brightness are analyzed as an example. To provide a reliable identification of parameters of star active regions responsible for the fast variableness, an experiment is proposed, the ''synchronous spectroscopy'' method being used. The method is based on the supposition about temporary stationarity of occasional processes within the limits of the time scale of several hours. The block diagram of the experiment is described

  20. Variable geometry Darrieus wind machine

    Science.gov (United States)

    Pytlinski, J. T.; Serrano, D.

    1983-08-01

    A variable geometry Darrieus wind machine is proposed. The lower attachment of the blades to the rotor can move freely up and down the axle allowing the blades of change shape during rotation. Experimental data for a 17 m. diameter Darrieus rotor and a theoretical model for multiple streamtube performance prediction were used to develop a computer simulation program for studying parameters that affect the machine's performance. This new variable geometry concept is described and interrelated with multiple streamtube theory through aerodynamic parameters. The computer simulation study shows that governor behavior of a Darrieus turbine can not be attained by a standard turbine operating within normally occurring rotational velocity limits. A second generation variable geometry Darrieus wind turbine which uses a telescopic blade is proposed as a potential improvement on the studied concept.

  1. Progress with variable cycle engines

    Science.gov (United States)

    Westmoreland, J. S.

    1980-01-01

    The evaluation of components of an advanced propulsion system for a future supersonic cruise vehicle is discussed. These components, a high performance duct burner for thrust augmentation and a low jet noise coannular exhaust nozzle, are part of the variable stream control engine. An experimental test program involving both isolated component and complete engine tests was conducted for the high performance, low emissions duct burner with excellent results. Nozzle model tests were completed which substantiate the inherent jet noise benefit associated with the unique velocity profile possible of a coannular exhaust nozzle system on a variable stream control engine. Additional nozzle model performance tests have established high thrust efficiency levels at takeoff and supersonic cruise for this nozzle system. Large scale testing of these two critical components is conducted using an F100 engine as the testbed for simulating the variable stream control engine.

  2. COMPORTAMIENTO DE UN MATERIAL GRANULAR NO TRATADO EN ENSAYOS TRIAXIALES CÍCLICOS CON PRESIÓN DE CONFINAMIENTO CONSTANTE Y VARIABLE BEHAVIOR OF AN UNBOUND GRANULAR MATERIAL IN CYCLIC TRIAXIAL TESTS WITH CONSTANT AND VARIABLE CONFINING PRESSURE

    Directory of Open Access Journals (Sweden)

    Hugo Alexander Rondón Quintana

    2008-12-01

    Full Text Available En un pavimento, cada una de las capas de la estructura experimenta bajo una carga vehicular ciclos de esfuerzo con componentes vertical, horizontal y de corte. Para el estudio de materiales granulares no tratados (utilizados para conformar capas de base y subbase, la mayor parte de las investigaciones se realizan empleando equipos triaxiales cíclicos en donde sólo la carga vertical es cíclica y la presión de confinamiento permanece constante durante el ensayo. Un ensayo que reproduce mejor la forma como se distribuyen los esfuerzos en estas capas es el ensayo triaxial cíclico con presión de confinamiento variable. En este ensayo se pueden modelar las componentes cíclicas tanto en el sentido vertical como horizontal. A pesar que son ensayos distintos, la ingeniería de pavimentos supone que la respuesta que experimentan estos materiales en estos ensayos es similar, lo anterior basado en algunos estudios realizados en la década de los setenta. En la presente investigación se diseña y desarrolla un programa experimental más detallado, para comparar el comportamiento que desarrolla un material granular no tratado en estos ensayos. De los resultados se evidencia que sólo para algunas trayectorias de esfuerzo, la dirección y la acumulación de la deformación vertical y volumétrica es similar.In a pavement structure, passing wheel loads impose cyclic stresses consisting of vertical, horizontal and shear components. Studies of the behavior of unbound granular materials (UGM, used for base and sub-base layers under cyclic loading are mostly performed using the axisymmetric triaxial test with constant confining pressure (CCP test and a cyclic variation of the axial stress. However, in this type of test only the vertical component of the cyclic stress path is considered. The oscillation of the horizontal stress can be reproduced by an additional cyclic variation of the confining pressure (VCP test. CCP and VCP tests are sometimes assumed to

  3. Complex Variables throughout the Curriculum

    Science.gov (United States)

    D'Angelo, John P.

    2017-01-01

    We offer many specific detailed examples, several of which are new, that instructors can use (in lecture or as student projects) to revitalize the role of complex variables throughout the curriculum. We conclude with three primary recommendations: revise the syllabus of Calculus II to allow early introductions of complex numbers and linear…

  4. Visualization of Variation and Variability

    NARCIS (Netherlands)

    Busking, S.

    2014-01-01

    As datasets grow in size and complexity, the importance of comparison as a tool for analysis is growing. We define comparison as the act of analyzing variation or variability based on two or more specific instances of the data. This thesis explores a number of cases spread across the range of

  5. Compact plasmonic variable optical attenuator

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Rosenzveig, Tiberiu; Hermannsson, Pétur Gordon

    2008-01-01

    We demonstrate plasmonic nanowire-based thermo-optic variable optical attenuators operating in the 1525-1625 nm wavelength range. The devices have a footprint as low as 1 mm, extinction ratio exceeding 40 dB, driving voltage below 3 V, and full modulation bandwidth of 1 kHz. The polarization...

  6. Variable & Recode Definitions - SEER Documentation

    Science.gov (United States)

    Resources that define variables and provide documentation for reporting using SEER and related datasets. Choose from SEER coding and staging manuals plus instructions for recoding behavior, site, stage, cause of death, insurance, and several additional topics. Also guidance on months survived, calculating Hispanic mortality, and site-specific surgery.

  7. Unsupervised classification of variable stars

    Science.gov (United States)

    Valenzuela, Lucas; Pichara, Karim

    2018-03-01

    During the past 10 years, a considerable amount of effort has been made to develop algorithms for automatic classification of variable stars. That has been primarily achieved by applying machine learning methods to photometric data sets where objects are represented as light curves. Classifiers require training sets to learn the underlying patterns that allow the separation among classes. Unfortunately, building training sets is an expensive process that demands a lot of human efforts. Every time data come from new surveys; the only available training instances are the ones that have a cross-match with previously labelled objects, consequently generating insufficient training sets compared with the large amounts of unlabelled sources. In this work, we present an algorithm that performs unsupervised classification of variable stars, relying only on the similarity among light curves. We tackle the unsupervised classification problem by proposing an untraditional approach. Instead of trying to match classes of stars with clusters found by a clustering algorithm, we propose a query-based method where astronomers can find groups of variable stars ranked by similarity. We also develop a fast similarity function specific for light curves, based on a novel data structure that allows scaling the search over the entire data set of unlabelled objects. Experiments show that our unsupervised model achieves high accuracy in the classification of different types of variable stars and that the proposed algorithm scales up to massive amounts of light curves.

  8. Cataclysmic variables observed with INTEGRAL

    Czech Academy of Sciences Publication Activity Database

    Šimon, Vojtěch; Hudec, René; Münz, Filip; Štrobl, Jan

    2006-01-01

    Roč. 6, č. 1 (2006), s. 149-154 ISSN 1009-9271 R&D Projects: GA ČR GA205/05/2167 Institutional research plan: CEZ:AV0Z10030501 Keywords : cataclysmic variables * intermediate polars * X-rays Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.746, year: 2006

  9. Choice of the thermodynamic variables

    International Nuclear Information System (INIS)

    Balian, R.

    1985-09-01

    Some basic ideas of thermodynamics and statistical mechanics, both at equilibrium and off equilibrium, are recalled. In particular, the selection of relevant variables which underlies any macroscopic description is discussed, together with the meaning of the various thermodynamic quantities, in order to set the thermodynamic approaches used in nuclear physics in a general prospect [fr

  10. Marginality and Variability in Esperanto.

    Science.gov (United States)

    Brent, Edmund

    This paper discusses Esperanto as a planned language and refutes three myths connected to it, namely, that Esperanto is achronical, atopical, and apragmatic. The focus here is on a synchronic analysis. Synchronic variability is studied with reference to the structuralist determination of "marginality" and the dynamic linguistic…

  11. Contextual Variability in Free Recall

    Science.gov (United States)

    Lohnas, Lynn J.; Polyn, Sean M.; Kahana, Michael J.

    2011-01-01

    According to contextual-variability theory, experiences encoded at different times tend to be associated with different contextual states. The gradual evolution of context implies that spaced items will be associated with more distinct contextual states, and thus have more unique retrieval cues, than items presented in proximity. Ross and Landauer…

  12. Solar-cosmic-ray variability

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1976-01-01

    The maximum flux of particles from solar events that should be considered in designing the shielding for a space habitation is discussed. The activities of various radionuclides measured in the top few centimeters of lunar rocks are used to examine the variability of solar cosmic ray fluxes over the last five million years. 10 references

  13. Operant Variability: A Conceptual Analysis

    Science.gov (United States)

    Barba, Lourenco de Souza

    2012-01-01

    Some researchers claim that variability is an operant dimension of behavior. The present paper reviews the concept of operant behavior and emphasizes that differentiation is the behavioral process that demonstrates an operant relation. Differentiation is conceived as change in the overlap between two probability distributions: the distribution of…

  14. Extraction Methods, Variability Encountered in

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Nelson, K.E.

    2014-01-01

    Synonyms Bias in DNA extractions methods; Variation in DNA extraction methods Definition The variability in extraction methods is defined as differences in quality and quantity of DNA observed using various extraction protocols, leading to differences in outcome of microbial community composition

  15. Beat to beat variability in cardiovascular variables: noise or music?

    Science.gov (United States)

    Appel, M. L.; Berger, R. D.; Saul, J. P.; Smith, J. M.; Cohen, R. J.

    1989-01-01

    Cardiovascular variables such as heart rate, arterial blood pressure, stroke volume and the shape of electrocardiographic complexes all fluctuate on a beat to beat basis. These fluctuations have traditionally been ignored or, at best, treated as noise to be averaged out. The variability in cardiovascular signals reflects the homeodynamic interplay between perturbations to cardiovascular function and the dynamic response of the cardiovascular regulatory systems. Modern signal processing techniques provide a means of analyzing beat to beat fluctuations in cardiovascular signals, so as to permit a quantitative, noninvasive or minimally invasive method of assessing closed loop hemodynamic regulation and cardiac electrical stability. This method promises to provide a new approach to the clinical diagnosis and management of alterations in cardiovascular regulation and stability.

  16. Relationship between socio-demographic and clinical variables, and health-related quality of life in patients with inflammatory bowel disease Relación entre variables sociodemográficas y clínicas y calidad de vida relacionada con la salud en pacientes con enfermedad inflamatoria intestinal

    Directory of Open Access Journals (Sweden)

    B. López Blanco

    2005-12-01

    la cirugía y la necesidad de apoyo psicológico aparecieron relacionadas con la calidad de vida relacionada con la salud. Conclusiones: la identificación de las variables de calidad de vida relacionada con la salud en pacientes con enfermedad inflamatoria intestinal parece vinculada básicamente a elementos externos al tipo de enfermedad. El conocimiento de tales elementos puede resultar muy útil para orientar y modificar factores específicos en futuras actuaciones.

  17. Risk assessment of groundwater level variability using variable Kriging methods

    Science.gov (United States)

    Spanoudaki, Katerina; Kampanis, Nikolaos A.

    2015-04-01

    Assessment of the water table level spatial variability in aquifers provides useful information regarding optimal groundwater management. This information becomes more important in basins where the water table level has fallen significantly. The spatial variability of the water table level in this work is estimated based on hydraulic head measured during the wet period of the hydrological year 2007-2008, in a sparsely monitored basin in Crete, Greece, which is of high socioeconomic and agricultural interest. Three Kriging-based methodologies are elaborated in Matlab environment to estimate the spatial variability of the water table level in the basin. The first methodology is based on the Ordinary Kriging approach, the second involves auxiliary information from a Digital Elevation Model in terms of Residual Kriging and the third methodology calculates the probability of the groundwater level to fall below a predefined minimum value that could cause significant problems in groundwater resources availability, by means of Indicator Kriging. The Box-Cox methodology is applied to normalize both the data and the residuals for improved prediction results. In addition, various classical variogram models are applied to determine the spatial dependence of the measurements. The Matérn model proves to be the optimal, which in combination with Kriging methodologies provides the most accurate cross validation estimations. Groundwater level and probability maps are constructed to examine the spatial variability of the groundwater level in the basin and the associated risk that certain locations exhibit regarding a predefined minimum value that has been set for the sustainability of the basin's groundwater resources. Acknowledgement The work presented in this paper has been funded by the Greek State Scholarships Foundation (IKY), Fellowships of Excellence for Postdoctoral Studies (Siemens Program), 'A simulation-optimization model for assessing the best practices for the

  18. Preço de transferência : os efeitos fiscais e financeiros de produtos importados de uma empresa vinculada

    OpenAIRE

    Paulo Henrique Eccel de Araujo

    2013-01-01

    Em decorrência das regras de preço de transferência adotadas no Brasil, os produtos ou mercadorias importados de empresas do mesmo grupo econômico ou que possuem controle comum, faz-se necessário um método de controle para que essas operações sejam lucrativas ou ao menos deem o retorno almejado para as empresas. Esse trabalho tem como objetivo demonstrar o que é o preço de transferência no Brasil, quais são os métodos a serem utilizados, a confecção de um controle dessas operações e a compara...

  19. Notificaciones en el procedimiento administrativo. Análisis de las modificatorias vinculadas al decreto legislativo 1029.

    Directory of Open Access Journals (Sweden)

    Jorge Pando Vilchez

    2011-12-01

    Full Text Available La notificación, institución de singular importancia en el procedimiento administrativo, ha sido objeto de modificaciones introducidas por el decreto legislativo 1029. Estas modificaciones, si bien son un avance en la regulación, presentan deficiencias que podrían perjudicar la propia institución de la notificación, ya que mantienen aspectos no regulados y que debieran ser tema de la agenda inmediata.

  20. Las ciencias naturales me generan... emociones vinculadas a las ciencias en la formación docente permanente

    OpenAIRE

    Mengascini, Adriana

    2017-01-01

    Presentamos y discutimos resultados de una indagación realizada en el contexto de una propuesta de formación docente permanente, respecto de las emociones asociadas a las ciencias naturales, a su enseñanza y a la realización de trabajos experimentales entre docentes de primaria y secundaria de Argentina. Las emociones manifestadas hacia las ciencias fueron positivas (interés, atracción, motivación), aunque respecto de su enseñanza y la realización de actividades experimentales se expresaron a...

  1. Soil variability in engineering applications

    Science.gov (United States)

    Vessia, Giovanna

    2014-05-01

    Natural geomaterials, as soils and rocks, show spatial variability and heterogeneity of physical and mechanical properties. They can be measured by in field and laboratory testing. The heterogeneity concerns different values of litho-technical parameters pertaining similar lithological units placed close to each other. On the contrary, the variability is inherent to the formation and evolution processes experienced by each geological units (homogeneous geomaterials on average) and captured as a spatial structure of fluctuation of physical property values about their mean trend, e.g. the unit weight, the hydraulic permeability, the friction angle, the cohesion, among others. The preceding spatial variations shall be managed by engineering models to accomplish reliable designing of structures and infrastructures. Materon (1962) introduced the Geostatistics as the most comprehensive tool to manage spatial correlation of parameter measures used in a wide range of earth science applications. In the field of the engineering geology, Vanmarcke (1977) developed the first pioneering attempts to describe and manage the inherent variability in geomaterials although Terzaghi (1943) already highlighted that spatial fluctuations of physical and mechanical parameters used in geotechnical designing cannot be neglected. A few years later, Mandelbrot (1983) and Turcotte (1986) interpreted the internal arrangement of geomaterial according to Fractal Theory. In the same years, Vanmarcke (1983) proposed the Random Field Theory providing mathematical tools to deal with inherent variability of each geological units or stratigraphic succession that can be resembled as one material. In this approach, measurement fluctuations of physical parameters are interpreted through the spatial variability structure consisting in the correlation function and the scale of fluctuation. Fenton and Griffiths (1992) combined random field simulation with the finite element method to produce the Random

  2. Polarimetry of magnetic catalysmic variables

    Energy Technology Data Exchange (ETDEWEB)

    Cropper, M

    1985-01-01

    The design and construction of an astronomical polarimeter is described and an evaluation made of its performance. Extensive observations of cataclysmic variables with emphasis on the AM Her and DQ Her classes are then presented. The polarimeter permitted simultaneous linear and circular polarisation measurements, or, by rearranging the order of the retarders in the beam, linear polarisation measurements alone, or circular polarisation measurements alone, with enhanced efficiency. Extensive sets of observations using the polarimeter were obtained for six of the ten AM Her variables. A comparison was made between the competing models for the cyclotron emission, showing that those which take into account the temperature structure of the accretion region provide the best results.

  3. Photometric variability in earthshine observations.

    Science.gov (United States)

    Langford, Sally V; Wyithe, J Stuart B; Turner, Edwin L

    2009-04-01

    The identification of an extrasolar planet as Earth-like will depend on the detection of atmospheric signatures or surface non-uniformities. In this paper we present spatially unresolved flux light curves of Earth for the purpose of studying a prototype extrasolar terrestrial planet. Our monitoring of the photometric variability of earthshine revealed changes of up to 23% per hour in the brightness of Earth's scattered light at around 600 nm, due to the removal of specular reflection from the view of the Moon. This variability is accompanied by reddening of the spectrum and results from a change in surface properties across the continental boundary between the Indian Ocean and Africa's east coast. Our results based on earthshine monitoring indicate that specular reflection should provide a useful tool in determining the presence of liquid water on extrasolar planets via photometric observations.

  4. Continuous-Variable Entanglement Swapping

    Directory of Open Access Journals (Sweden)

    Kevin Marshall

    2015-05-01

    Full Text Available We present a very brief overview of entanglement swapping as it relates to continuous-variable quantum information. The technical background required is discussed and the natural link to quantum teleportation is established before discussing the nature of Gaussian entanglement swapping. The limitations of Gaussian swapping are introduced, along with the general applications of swapping in the context of to quantum communication and entanglement distribution. In light of this, we briefly summarize a collection of entanglement swapping schemes which incorporate a non-Gaussian ingredient and the benefits of such schemes are noted. Finally, we motivate the need to further study and develop such schemes by highlighting requirements of a continuous-variable repeater.

  5. Variable frequency microwave heating apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Bible, D.W.; Lauf, R.J.; Johnson, A.C.; Thigpen, L.T.

    1999-10-05

    A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

  6. Biological variability of glycated hemoglobin.

    Science.gov (United States)

    Braga, Federica; Dolci, Alberto; Mosca, Andrea; Panteghini, Mauro

    2010-11-11

    The measurement of glycated hemoglobin (HbA(1c)) has a pivotal role in monitoring glycemic state in diabetic patients. Furthermore, the American Diabetes Association has recently recommended the use of HbA(1c) for diabetes diagnosis, but a clear definition of the clinically allowable measurement error is still lacking. Information on biological variability of the analyte can be used to achieve this goal. We systematically reviewed the published studies on the biological variation of HbA(1c) to check consistency of available data in order to accurately define analytical goals. The nine recruited studies were limited by choice of analytic methodology, population selection, protocol application and statistical analyses. There is an urgent need to determine biological variability of HbA(1c) using a specific and traceable assay, appropriate protocol and appropriate statistical evaluation of data. 2010 Elsevier B.V. All rights reserved.

  7. RADIO VARIABILITY IN SEYFERT NUCLEI

    International Nuclear Information System (INIS)

    Mundell, C. G.; Ferruit, P.; Nagar, N.; Wilson, A. S.

    2009-01-01

    Comparison of 8.4 GHz radio images of a sample of eleven, early-type Seyfert galaxies with previous observations reveals possible variation in the nuclear radio flux density in five of them over a seven year period. Four Seyferts (NGC 2110, NGC 3081, MCG -6-30-15, and NGC 5273) show a decline in their 8.4 GHz nuclear flux density between 1992 and 1999, while one (NGC 4117) shows an increase; the flux densities of the remaining six Seyferts (Mrk 607, NGC 1386, Mrk 620, NGC 3516, NGC 4968, and NGC 7465) have remained constant over this period. New images of MCG -5-23-16 are also presented. We find no correlation between radio variability and nuclear radio luminosity or Seyfert nuclear type, although the sample is small and dominated by type 2 Seyferts. Instead, a possible correlation between the presence of nuclear radio variability and the absence of hundred parsec-scale radio emission is seen, with four out of five marginally resolved or unresolved nuclei showing a change in nuclear flux density, while five out of six extended sources show no nuclear variability despite having unresolved nuclear sources. NGC 2110 is the only source in our sample with significant extended radio structure and strong nuclear variability (∼38% decline in nuclear flux density over seven years). The observed nuclear flux variability indicates significant changes are likely to have occurred in the structure of the nucleus on scales smaller than the VLA beam size (i.e., within the central ∼0.''1 (15 pc)), between the two epochs, possibly due to the appearance and fading of new components or shocks in the jet, consistent with previous detection of subparsec-scale nuclear structure in this Seyfert. Our results suggest that all Seyferts may exhibit variation in their nuclear radio flux density at 8.4 GHz, but that variability is more easily recognized in compact sources in which emission from the variable nucleus is not diluted by unresolved, constant flux density radio jet emission

  8. Variables associated with active spondylolysis.

    Science.gov (United States)

    Gregg, Chris D; Dean, Sarah; Schneiders, Anthony G

    2009-11-01

    Retrospective non-experimental study. To investigate variables associated with active spondylolysis. A retrospective study audited clinical data over a two year period from patients with suspected spondylolysis that were referred for a SPECT bone scan. Six exploratory variables were identified and analysed using uni- and multi-variate regression from 82 patient records to determine the association between symptomatic, physical and demographic characteristics, and the presence of an active spondylolysis. Tertiary level multidisciplinary private practice sports medicine clinic. All patients with low back pain that required a SPECT bone scan to confirm suspected spondylolysis. 82 subjects were included in the final sample group. The six exploratory variables included Age, Gender, Injury duration, Injury onset, Sports participation and the result of the Single Leg Hyperextension Test. The dependent outcome variable was the result of the SPECT bone scan (scan-positive or scan-negative). Adolescent males had a higher incidence of spondylolysis detected by SPECT bone scan compared to other patients and a statistically significant association was demonstrated for both age (p=0.01) and gender (p=0.01). Subjects with an active spondylolysis were nearly five times more likely to be male and aged less than 20 years. Furthermore, the likelihood ratio indicated that adolescent males with suspected spondylolysis were three and a half times more likely to have a positive bone scan result. The Single Leg Hyperextension Test did not demonstrate a statistically significant association with spondylolysis (p=0.47). Clinicians assessing for a predisposition to the development of spondylolysis should consider the gender and age of the patient and not rely on the predictive ability of the Single Leg Hyperextension Test.

  9. Ashtekar formalism with real variables

    International Nuclear Information System (INIS)

    Kalau, W.; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

    1990-12-01

    A new approach to canonical gravity is presented which is based on the Ashtekar formalism. But, in contrast to Ashtekar's variables, this formulation does not need complex quantities nor does it lead to second class constraints. This is achieved using SO(3,1) as a gauge group instead of complexified SO(3). Because of the larger group additional first class constraints are needed which turn out to be cubic and quartic in the momenta. (author). 13 refs

  10. Dynamics of Variable Mass Systems

    Science.gov (United States)

    Eke, Fidelis O.

    1998-01-01

    This report presents the results of an investigation of the effects of mass loss on the attitude behavior of spinning bodies in flight. The principal goal is to determine whether there are circumstances under which the motion of variable mass systems can become unstable in the sense that their transverse angular velocities become unbounded. Obviously, results from a study of this kind would find immediate application in the aerospace field. The first part of this study features a complete and mathematically rigorous derivation of a set of equations that govern both the translational and rotational motions of general variable mass systems. The remainder of the study is then devoted to the application of the equations obtained to a systematic investigation of the effect of various mass loss scenarios on the dynamics of increasingly complex models of variable mass systems. It is found that mass loss can have a major impact on the dynamics of mechanical systems, including a possible change in the systems stability picture. Factors such as nozzle geometry, combustion chamber geometry, propellant's initial shape, size and relative mass, and propellant location can all have important influences on the system's dynamic behavior. The relative importance of these parameters on-system motion are quantified in a way that is useful for design purposes.

  11. AEROSOL VARIABILITY OBSERVED WITH RPAS

    Directory of Open Access Journals (Sweden)

    B. Altstädter

    2013-08-01

    Full Text Available To observe the origin, vertical and horizontal distribution and variability of aerosol particles, and especially ultrafine particles recently formed, we plan to employ the remotely piloted aircraft system (RPAS Carolo-P360 "ALADINA" of TU Braunschweig. The goal of the presented project is to investigate the vertical and horizontal distribution, transport and small-scale variability of aerosol particles in the atmospheric boundary layer using RPAS. Two additional RPAS of type MASC of Tübingen University equipped with turbulence instrumentation add the opportunity to study the interaction of the aerosol concentration with turbulent transport and exchange processes of the surface and the atmosphere. The combination of different flight patterns of the three RPAS allows new insights in atmospheric boundary layer processes. Currently, the different aerosol sensors are miniaturized at the Leibniz Institute for Tropospheric Research, Leipzig and together with the TU Braunschweig adapted to fit into the RPAS. Moreover, an additional meteorological payload for measuring temperature, humidity and turbulence properties is constructed by Tübingen University. Two condensation particle counters determine the total aerosol number with a different lower detection threshold in order to investigate the horizontal and vertical aerosol variability and new particle formation (aerosol particles of some nm diameter. Further the aerosol size distribution in the range from about 0.300 to ~5 μm is given by an optical particle counter.

  12. Hardness variability in commercial technologies

    International Nuclear Information System (INIS)

    Shaneyfelt, M.R.; Winokur, P.S.; Meisenheimer, T.L.; Sexton, F.W.; Roeske, S.B.; Knoll, M.G.

    1994-01-01

    The radiation hardness of commercial Floating Gate 256K E 2 PROMs from a single diffusion lot was observed to vary between 5 to 25 krad(Si) when irradiated at a low dose rate of 64 mrad(Si)/s. Additional variations in E 2 PROM hardness were found to depend on bias condition and failure mode (i.e., inability to read or write the memory), as well as the foundry at which the part was manufactured. This variability is related to system requirements, and it is shown that hardness level and variability affect the allowable mode of operation for E 2 PROMs in space applications. The radiation hardness of commercial 1-Mbit CMOS SRAMs from Micron, Hitachi, and Sony irradiated at 147 rad(Si)/s was approximately 12, 13, and 19 krad(Si), respectively. These failure levels appear to be related to increases in leakage current during irradiation. Hardness of SRAMs from each manufacturer varied by less than 20%, but differences between manufacturers are significant. The Qualified Manufacturer's List approach to radiation hardness assurance is suggested as a way to reduce variability and to improve the hardness level of commercial technologies

  13. Clinical variables in radiotracer biodistributions

    International Nuclear Information System (INIS)

    Lentle, B.C.; Scott, J.R.; Schmidt, R.P.; Noujaim, A.A.

    1981-01-01

    Radionuclide dosimetry must, by its nature, define tissue irradiation in terms of mean exposure in a population of a statistically acceptable size. In the daily practice of clinical nuclear medicine there are, however, quite large variations in the biodistribution of tracers and thus in resulting radiation doses. Age is a variable, particularly in respect of bone-seeking tracers. Sex imposes variations in radiation dose on account of the differing anatomical configurations of the gonads. Breast uptake and excretion of certain tracers in women are additional variables. Activity and occupation are occasional variables. Numerous iatrogenic causes of altered radiotracer biodistributions have been described. Cancer chemotherapy is a particularly potent cause of changed biodistributions while even a trivial matter such as preparing the skin with an iodine containing antiseptic may cause displacement of technetium from its compounds. In the blocking of thyroid uptake of radioiodines, there is good precedent for the manipulation of regional tissue dosimetry. It is possible to go beyond the mere cataloguing of these effects to look creatively at the subject of comparative tissue biodistributions and hence comparative dosimetry. Effects such as the clinical observation of the interference by cis-platinum with the usual biodistribution of radio-gallium suggest that such compounds can be used as probes each to lead to a better understanding of the mechanism of action of the other

  14. An evaluation of FIA's stand age variable

    Science.gov (United States)

    John D. Shaw

    2015-01-01

    The Forest Inventory and Analysis Database (FIADB) includes a large number of measured and computed variables. The definitions of measured variables are usually well-documented in FIA field and database manuals. Some computed variables, such as live basal area of the condition, are equally straightforward. Other computed variables, such as individual tree volume,...

  15. Search for the Higgs Boson in the H{yields} ZZ{sup (*)}{yields}4{mu} Channel in CMS Using a Multivariate Analysis; Busqueda del Boson de Higgs en el Canal H{yields} ZZ{sup (*)}{yields}4{mu} en CMS Empleando un Metodo de Analisis Multivariado

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Diaz, A.

    2007-12-28

    This note presents a Higgs boson search analysis in the CMS detector of the LHC accelerator (CERN, Geneva, Switzerland) in the H{yields} ZZ{sup (*)}{yields}4{mu} channel, using a multivariate method. This analysis, based in a Higgs boson mass dependent likelihood, constructed from discriminant variables, provides a significant improvement of the Higgs boson discovery potential in a wide mass range with respect to the official analysis published by CMS, based in orthogonal cuts independent of the Higgs boson mass. (Author) 8 refs.

  16. Utilization technique on variable speed device

    International Nuclear Information System (INIS)

    1989-12-01

    This reports of workshop on power technology describes using technique on variable speed device, which deals with alternating current situation and prospect of current variable speed device, technical trend and prospect of electronics, reduce expenses by variable speed device, control technique, measurement technology, high voltage variable speed device, recent trend of inverter technology, low voltage and high voltage variable speed device control device, operating variable speed device in cooling fan, FDF application and defect case of variable speed device, cooling pump application of water variable transformer, inverter application and energy effect of ventilation equipment, application of variable speed device and analysis of the result of operation and study for application of variable speed technology.

  17. Heart rate variability in newborns.

    Science.gov (United States)

    Javorka, K; Lehotska, Z; Kozar, M; Uhrikova, Z; Kolarovszki, B; Javorka, M; Zibolen, M

    2017-09-22

    Heart rate (HR) and heart rate variability (HRV) in newborns is influenced by genetic determinants, gestational and postnatal age, and other variables. Premature infants have a reduced HRV. In neonatal HRV evaluated by spectral analysis, a dominant activity can be found in low frequency (LF) band (combined parasympathetic and sympathetic component). During the first postnatal days the activity in the high frequency (HF) band (parasympathetic component) rises, together with an increase in LF band and total HRV. Hypotrophy in newborn can cause less mature autonomic cardiac control with a higher contribution of sympathetic activity to HRV as demonstrated by sequence plot analysis. During quiet sleep (QS) in newborns HF oscillations increase - a phenomenon less expressed or missing in premature infants. In active sleep (AS), HRV is enhanced in contrast to reduced activity in HF band due to the rise of spectral activity in LF band. Comparison of the HR and HRV in newborns born by physiological vaginal delivery, without (VD) and with epidural anesthesia (EDA) and via sectio cesarea (SC) showed no significant differences in HR and in HRV time domain parameters. Analysis in the frequency domain revealed, that the lowest sympathetic activity in chronotropic cardiac chronotropic regulation is in the VD group. Different neonatal pathological states can be associated with a reduction of HRV and an improvement in the health conditions is followed by changes in HRV what can be use as a possible prognostic marker. Examination of heart rate variability in neonatology can provide information on the maturity of the cardiac chronotropic regulation in early postnatal life, on postnatal adaptation and in pathological conditions about the potential dysregulation of cardiac function in newborns, especially in preterm infants.

  18. Pleistocene Indian Monsoon Rainfall Variability

    Science.gov (United States)

    Yirgaw, D. G.; Hathorne, E. C.; Giosan, L.; Collett, T. S.; Sijingeo, A. V.; Nath, B. N.; Frank, M.

    2014-12-01

    The past variability of the Indian Monsoon is mostly known from records of wind strength over the Arabian Sea. Here we investigate proxies for fresh water input and runoff in a region of strong monsoon precipitation that is a major moisture source for the east Asian Monsoon. A sediment core obtained by the IODP vessel JOIDES Resolution and a gravity core from the Alcock Seamount complex in the Andaman Sea are used to examine the past monsoon variability on the Indian sub-continent and directly over the ocean. The current dataset covers the last glacial and deglacial but will eventually provide a Pleistocene record. We utilise the ecological habitats of G. sacculifer and N. dutertrei to investigate the freshwater-induced stratification with paired Mg/Ca and δ18O analyses to estimate seawater δ18O (δ18Osw). During the last 60 kyrs, Ba/Ca ratios and δ18Osw values generally agree well between the two cores and suggest the weakest surface runoff and monsoon during the LGM and strongest monsoon during the Holocene. The difference in δ18O between the species, interpreted as a proxy for upper ocean stratification, implies stratification developed around 37 ka and remained relatively constant during the LGM, deglacial and Holocene. To investigate monsoon variability for intervals in the past, single shell Mg/Ca and δ18O analyses have been conducted. Mg/Ca ratios from individual shells of N. dutertrei suggest relatively small changes in temperature. However, individual N. dutertrei δ18O differ greatly between the mid-Holocene and samples from the LGM and a nearby core top. The mid-Holocene individuals have a greater range and large skew towards negative values indicating greater fresh water influence.

  19. The masses of cataclysmic variables

    International Nuclear Information System (INIS)

    Robinson, E.L.

    1976-01-01

    Masses are derived for the individual components of six cataclysmic variables. There is a considerable spread in the masses of the white dwarf components, which range from 0.73 M/sub sun/ in EM Cyg to 1.26 M/sub sun/ in Z Cam. All of the white dwarfs have masses greater than 0.70 M/sub sun/, but there is no evidence that there is any preferred mass. It is found that the morphology of the eruptions (i.e., nova versus dwarf nova) is independent of the mass of both the white dwarf and the late-type star

  20. Variable retinal presentations in nanophthalmos

    International Nuclear Information System (INIS)

    Khan, A.; Zafar, S.N.

    2009-01-01

    Nanophthalmos is an uncommon developmental ocular disorder characterized by a small eye with short axial length, high hyperopia and high lens/eye volume ratio due to arrested development of the globe in all directions. Different types of fundus changes can rarely occur with nanophthalmos. We describe five cases of nanophthalmos, each of them presenting with a different fundus appearance. Our case series highlights variability of pigmentary changes from retinal flecks to bone spicules and bull's eye maculopathy, which are rare in the combinations described here. (author)

  1. Continuous-variable quantum games

    International Nuclear Information System (INIS)

    Li Hui; Du Jiangfeng; Massar, Serge

    2002-01-01

    We investigate the quantization of games in which the players can access to a continuous set of classical strategies, making use of continuous-variable quantum systems. For the particular case of the Cournot's duopoly, we find that, even though the two players both act as 'selfishly' in the quantum game as they do in the classical game, they are found to virtually cooperate due to the quantum entanglement between them. We also find that the original Einstein-Podolksy-Rosen state contributes to the best profits that the two firms could ever attain. Moreover, we propose a practical experimental setup for the implementation of such quantum games

  2. Variability of ethane on Jupiter

    Science.gov (United States)

    Kostiuk, Theodor; Espenak, Fred; Mumma, Michael J.; Deming, Drake; Zipoy, David

    1987-01-01

    Varying stratospheric temperature profiles and C2H6 altitude distributions furnish contexts for the evaluation of ethane abundances and distributions in the Jupiter stratosphere. Substantial ethane line emission and retrieved mole fraction variability is noted near the footprint of Io's flux tube, as well as within the auroral regions. It is suggested that this and other observed phenomena are due to the modification of local stratospheric chemistry by higher-order effects, which are in turn speculated to be due to the precipitation of charged particles along magnetic field lines.

  3. Climatic variability of east Malaysia

    International Nuclear Information System (INIS)

    Camerlengo, A.L.; Saadon, M.N.; Awang, M.; Somchit, H.; Rang, L.Y.

    2001-01-01

    The objective of this paper is to learn the variability of atmospheric pressure, relative humidity and insolation in East Malaysia. The main results of our study are: (1) a gentle pressure gradient is observed at the east coast in the boreal winter, (2) smaller atmospheric pressure values are noted during the first inter-monsoon period all across East Malaysia, (3) lesser insolation values are observed in Sarawak and at the east coast during the boreal winter as compared to the boreal summer, and (4) a poleward increase of insolation is registered. (author)

  4. Pulse timing for cataclysmic variables

    International Nuclear Information System (INIS)

    Chester, T.J.

    1979-01-01

    It is shown that present pulse timing measurements of cataclysmic variables can be explained by models of accretion disks in these systems, and thus such measurements can constrain disk models. The model for DQ Her correctly predicts the amplitude variation of the continuum pulsation and can also perhaps explain the asymmetric amplitude of the pulsed lambda4686 emission line. Several other predictions can be made from the model. In particular, if pulse timing measurements that resolve emission lines both in wavelength and in binary phase can be made, the projected orbital radius of the white dwarf could be deduced

  5. Reflecting variable opening insulating panel

    International Nuclear Information System (INIS)

    Nungesser, W.T.

    1976-01-01

    A description is given of a reflecting variable opening insulating panel assembly, comprising a static panel assembly of reflecting insulation sheets forming a cavity along one side of the panel and a movable panel opening out by sliding from the cavity of the static panel, and a locking device for holding the movable panel in a position extending from the cavity of the static panel. This can apply to a nuclear reactor of which the base might require maintenance and periodical checking and for which it is desirable to have available certain processes for the partial dismantling of the insulation [fr

  6. Influence of the deep fat frying process on the lipid profile of the fat contained in the french type fried potato using palm olein; Influencia del proceso de fritura en profundidad sobre el perfil lipidico de la grasa contenida en patatas tipo french, empleando oleina de palma

    Energy Technology Data Exchange (ETDEWEB)

    Marcano, J.; Rosa, Y. la; Salinas

    2010-07-01

    The aim of this investigation was to evaluate the influence of certain variables of the process of deep fat frying on the lipid profile of the fat fraction of the potato type french (Solanum tuberosum) using palm oil. This marked the first fat fraction of both the processing type and the oil used, through the evaluation of various physicochemical parameters, using the method of AOAC and the Standard COVENIN. We identified variables that influenced the process during frying of potatoes, using an experimental design of type 3 * 2{sup 2}, evaluating factors such as the reuse of the matrix fat (1st, the 4th and the 8th fry), temperature (150 degree centigrade and 180 degree centigrade) and method of food peeling (chemical and manual), studying the content of polar compounds as an indicator of the deterioration of the fat present in the potato, finding that oil reuse and peeling method significantly influenced in a positive manner, and that the temperature has a negative influence on the absorption of polar compounds in potato chips ({alpha}: 0.05). (Author) 23 refs.

  7. Classification and prediction of port variables

    Energy Technology Data Exchange (ETDEWEB)

    Molina Serrano, B.

    2016-07-01

    Many variables are included in planning and management of port terminals. They can beeconomic, social, environmental and institutional. Agent needs to know relationshipbetween these variables to modify planning conditions. Use of Bayesian Networks allowsfor classifying, predicting and diagnosing these variables. Bayesian Networks allow forestimating subsequent probability of unknown variables, basing on know variables.In planning level, it means that it is not necessary to know all variables because theirrelationships are known. Agent can know interesting information about how port variablesare connected. It can be interpreted as cause-effect relationship. Bayesian Networks can beused to make optimal decisions by introduction of possible actions and utility of theirresults.In proposed methodology, a data base has been generated with more than 40 port variables.They have been classified in economic, social, environmental and institutional variables, inthe same way that smart port studies in Spanish Port System make. From this data base, anetwork has been generated using a non-cyclic conducted grafo which allows for knowingport variable relationships - parents-children relationships-. Obtained network exhibits thateconomic variables are – in cause-effect terms- cause of rest of variable typologies.Economic variables represent parent role in the most of cases. Moreover, whenenvironmental variables are known, obtained network allows for estimating subsequentprobability of social variables.It has been concluded that Bayesian Networks allow for modeling uncertainty in aprobabilistic way, even when number of variables is high as occurs in planning andmanagement of port terminals. (Author)

  8. Variable speed electrical driving systems; Entrainements electriques a vitesse variable

    Energy Technology Data Exchange (ETDEWEB)

    Bonal, J. [ESE, Promethee, Groupe Schneider (France)

    1997-12-31

    This book is the first of a series of 3 volumes which synthesize the most recent knowledge on variable speed electrical driving systems. It is devoted to electronic and electromechanical engineers and technicians and to manufacturers of electrical equipments involving such systems. after a recall of basic electrotechnical and mechanical notions, this book focusses on the functionalities and criteria of definition of driving systems, and shows the interactions between the different parts of these equipments. It develops a methodological approach of the choice for the most suitable technology with respect to the application under consideration. Various industrial sectors are concerned and a particular attention is paid to the driving of receptive turbo-machineries which play a major role in the energy balance sheet of the industrial electrical power force. (J.S.) 28 refs.

  9. Progress on Variable Cycle Engines

    Science.gov (United States)

    Westmoreland, J. S.; Howlett, R. A.; Lohmann, R. P.

    1979-01-01

    Progress in the development and future requirements of the Variable Stream Control Engine (VSCE) are presented. The two most critical components of this advanced system for future supersonic transports, the high performance duct burner for thrust augmentation, and the low jet coannular nozzle were studied. Nozzle model tests substantiated the jet noise benefit associated with the unique velocity profile possible with a coannular nozzle system on a VSCE. Additional nozzle model performance tests have established high thrust efficiency levels only at takeoff and supersonic cruise for this nozzle system. An experimental program involving both isolated component and complete engine tests has been conducted for the high performance, low emissions duct burner with good results and large scale testing of these two components is being conducted using a F100 engine as the testbed for simulating the VSCE. Future work includes application of computer programs for supersonic flow fields to coannular nozzle geometries, further experimental testing with the duct burner segment rig, and the use of the Variable Cycle Engine (VCE) Testbed Program for evaluating the VSCE duct burner and coannular nozzle technologies.

  10. The variable finesse locking technique

    International Nuclear Information System (INIS)

    Acernese, F; Al-Shourbagy, M

    2006-01-01

    Virgo is a power recycled Michelson interferometer, with 3 km long Fabry-Perot cavities in the arms. The locking of the interferometer has been obtained with an original lock acquisition technique. The main idea is to lock the instrument away from its working point. Lock is obtained by misaligning the power recycling mirror and detuning the Michelson from the dark fringe. In this way, a good fraction of light escapes through the antisymmetric port and the power build-up inside the recycling cavity is extremely low. The benefit is that all the degrees of freedom are controlled when they are almost decoupled, and the linewidth of the recycling cavity is large. The interferometer is then adiabatically brought on to the dark fringe. This technique is referred to as variable finesse, since the recycling cavity is considered as a variable finesse Fabry-Perot. This technique has been widely tested and allows us to reach the dark fringe in few minutes, in an essentially deterministic way

  11. Variability of femoral muscle attachments.

    Science.gov (United States)

    Duda, G N; Brand, D; Freitag, S; Lierse, W; Schneider, E

    1996-09-01

    Analytical and experimental models of the musculoskeletal system often assume single values rather than ranges for anatomical input parameters. The hypothesis of the present study was that anatomical variability significantly influences the results of biomechanical analyses, specifically regarding the moment arms of the various thigh muscles. Insertions and origins of muscles crossing or attaching to the femur were digitized in six specimens. Muscle volumes were measured; muscle attachment area and centroid location were computed. To demonstrate the influence of inter-individual anatomic variability on a mechanical modeling parameter, the corresponding range of muscle moment arms were calculated. Standard deviations, as a percentage of the mean, were about 70% for attachment area and 80% for muscle volume and attachment centroid location. The resulting moment arms of the m. gluteus maximus and m. rectus femoris were especially sensitive to anatomical variations (SD 65%). The results indicate that sensitivity to anatomical variations should be analyzed in any investigation simulating musculoskeletal interactions. To avoid misinterpretations, investigators should consider using several anatomical configurations rather than relying on a mean data set.

  12. Pneumatic Variable Series Elastic Actuator.

    Science.gov (United States)

    Zheng, Hao; Wu, Molei; Shen, Xiangrong

    2016-08-01

    Inspired by human motor control theory, stiffness control is highly effective in manipulation and human-interactive tasks. The implementation of stiffness control in robotic systems, however, has largely been limited to closed-loop control, and suffers from multiple issues such as limited frequency range, potential instability, and lack of contribution to energy efficiency. Variable-stiffness actuator represents a better solution, but the current designs are complex, heavy, and bulky. The approach in this paper seeks to address these issues by using pneumatic actuator as a variable series elastic actuator (VSEA), leveraging the compressibility of the working fluid. In this work, a pneumatic actuator is modeled as an elastic element with controllable stiffness and equilibrium point, both of which are functions of air masses in the two chambers. As such, for the implementation of stiffness control in a robotic system, the desired stiffness/equilibrium point can be converted to the desired chamber air masses, and a predictive pressure control approach is developed to control the timing of valve switching to obtain the desired air mass while minimizing control action. Experimental results showed that the new approach in this paper requires less expensive hardware (on-off valve instead of proportional valve), causes less control action in implementation, and provides good control performance by leveraging the inherent dynamics of the actuator.

  13. CONSTRUCTING ACCOUNTING UNCERTAINITY ESTIMATES VARIABLE

    Directory of Open Access Journals (Sweden)

    Nino Serdarevic

    2012-10-01

    Full Text Available This paper presents research results on the BIH firms’ financial reporting quality, utilizing empirical relation between accounting conservatism, generated in created critical accounting policy choices, and management abilities in estimates and prediction power of domicile private sector accounting. Primary research is conducted based on firms’ financial statements, constructing CAPCBIH (Critical Accounting Policy Choices relevant in B&H variable that presents particular internal control system and risk assessment; and that influences financial reporting positions in accordance with specific business environment. I argue that firms’ management possesses no relevant capacity to determine risks and true consumption of economic benefits, leading to creation of hidden reserves in inventories and accounts payable; and latent losses for bad debt and assets revaluations. I draw special attention to recent IFRS convergences to US GAAP, especially in harmonizing with FAS 130 Reporting comprehensive income (in revised IAS 1 and FAS 157 Fair value measurement. CAPCBIH variable, resulted in very poor performance, presents considerable lack of recognizing environment specifics. Furthermore, I underline the importance of revised ISAE and re-enforced role of auditors in assessing relevance of management estimates.

  14. Correlated Temporal and Spectral Variability

    Science.gov (United States)

    Swank, Jean H.

    2007-01-01

    The variability of neutron star and black hole X-ray sources has several dimensions, because of the roles played by different important time-scales. The variations on time scales of hours, weeks, and months, ranging from 50% to orders of magnitude, arise out of changes in the flow in the disk. The most important driving forces for those changes are probably various possible instabilities in the disk, though there may be effects with other dominant causes. The changes in the rate of flow appear to be associated with changes in the flow's configuration, as the accreting material approaches the compact object, for there are generally correlated changes in both the Xray spectra and the character of the faster temporal variability. There has been a lot of progress in tracking these correlations, both for Z and Atoll neutron star low-mass X-ray binaries, and for black hole binaries. I will discuss these correlations and review briefly what they tell us about the physical states of the systems.

  15. ANÁLISIS NUMÉRICO DEL COMPORTAMIENTO DEL AIRE EN UN SISTEMA DE DISTRIBUCIÓN DE AIRE ACONDICIONADO EMPLEANDO LOS MODELOS DE TURBULENCIA k-e, RNG k-e Y EL MODELO DE LAS TENSIONES DE REYNOLDS NUMERICAL ANALYSIS OF AIR BEHAVIOR IN AN AIR CONDITIONING DISTRIBUTION SYSTEM USING k-ε TURBULENCE, RNG k-ε AND REYNOLDS TENSIONS METHODS

    Directory of Open Access Journals (Sweden)

    Luz Rodríguez Collado

    2008-09-01

    Full Text Available En la presente investigación se empleó el método de los volúmenes finitos para simular numéricamente el comportamiento termofluidodinámico del aire en un sistema de distribución de aire acondicionado. Se describió el modelo matemático que rige el comportamiento del flujo de aire en el conducto de distribución y el sistema de ecuaciones obtenido fue cerrado mediante la aplicación un modelo de turbulencia o cierre: para ello se emplearon de forma individual el modelo k-ε, el modelo RNG k-ε y el modelo de las tensiones de Reynolds. Fueron simulados tres casos de estudio y los resultados obtenidos de esas simulaciones indican que el modelo k-ε presenta un mejor comportamiento numérico en el problema simulado, generando menores residuos en las variables de flujo y un menor costo computacional.In the present investigation the finite volumes method was used to numerically simulate the thermofluiddynamic behavior of air in an air conditioning distribution system. The mathematical model that governs the behavior of airflow in the distribution duct was described by means of applying a turbulence or closure model: for this purpose k-ε, RNG k-ε and Reynolds Tensions models were used individually. Three cases were simulated and the results obtained from these simulations indicate that the k-ε model shows a better numerical behavior in the simulated problem, generating smaller residues in the flow variables and a reduced computing cost.

  16. Continuously variable focal length lens

    Science.gov (United States)

    Adams, Bernhard W; Chollet, Matthieu C

    2013-12-17

    A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.

  17. Variable-bias coin tossing

    International Nuclear Information System (INIS)

    Colbeck, Roger; Kent, Adrian

    2006-01-01

    Alice is a charismatic quantum cryptographer who believes her parties are unmissable; Bob is a (relatively) glamorous string theorist who believes he is an indispensable guest. To prevent possibly traumatic collisions of self-perception and reality, their social code requires that decisions about invitation or acceptance be made via a cryptographically secure variable-bias coin toss (VBCT). This generates a shared random bit by the toss of a coin whose bias is secretly chosen, within a stipulated range, by one of the parties; the other party learns only the random bit. Thus one party can secretly influence the outcome, while both can save face by blaming any negative decisions on bad luck. We describe here some cryptographic VBCT protocols whose security is guaranteed by quantum theory and the impossibility of superluminal signaling, setting our results in the context of a general discussion of secure two-party computation. We also briefly discuss other cryptographic applications of VBCT

  18. Winds in cataclysmic variable stars

    International Nuclear Information System (INIS)

    Cordova, F.A.; Ladd, E.F.; Mason, K.O.

    1984-01-01

    Ultraviolet spectrophotometry of two dwarf novae, CN Ori and RX And, at various phases of their outburst cycles confirms that the far uv flux increases dramatically about 1-2 days after the optical outburst begins. At this time the uv spectral line profiles indicate the presence of a high velocity wind. The detectability of the wind depends more on the steepness of the spectrum, and thus on the flux in the extreme ultraviolet, than on the absolute value of the far uv luminosity. The uv continuum during outburst consists of (at least) two components, the most luminous of which is located behind the wind and is completely absorbed by the wind at the line frequencies. Several pieces of evidence suggest that the uv emission lines that are observed in many cataclysmic variables during quiescence have a different location in the binary than the wind, and are affected very little by the outburst

  19. Variable-bias coin tossing

    Science.gov (United States)

    Colbeck, Roger; Kent, Adrian

    2006-03-01

    Alice is a charismatic quantum cryptographer who believes her parties are unmissable; Bob is a (relatively) glamorous string theorist who believes he is an indispensable guest. To prevent possibly traumatic collisions of self-perception and reality, their social code requires that decisions about invitation or acceptance be made via a cryptographically secure variable-bias coin toss (VBCT). This generates a shared random bit by the toss of a coin whose bias is secretly chosen, within a stipulated range, by one of the parties; the other party learns only the random bit. Thus one party can secretly influence the outcome, while both can save face by blaming any negative decisions on bad luck. We describe here some cryptographic VBCT protocols whose security is guaranteed by quantum theory and the impossibility of superluminal signaling, setting our results in the context of a general discussion of secure two-party computation. We also briefly discuss other cryptographic applications of VBCT.

  20. Variable flexure-based fluid filter

    Science.gov (United States)

    Brown, Steve B.; Colston, Jr., Billy W.; Marshall, Graham; Wolcott, Duane

    2007-03-13

    An apparatus and method for filtering particles from a fluid comprises a fluid inlet, a fluid outlet, a variable size passage between the fluid inlet and the fluid outlet, and means for adjusting the size of the variable size passage for filtering the particles from the fluid. An inlet fluid flow stream is introduced to a fixture with a variable size passage. The size of the variable size passage is set so that the fluid passes through the variable size passage but the particles do not pass through the variable size passage.

  1. Solar Variability Magnitudes and Timescales

    Science.gov (United States)

    Kopp, Greg

    2015-08-01

    The Sun’s net radiative output varies on timescales of minutes to many millennia. The former are directly observed as part of the on-going 37-year long total solar irradiance climate data record, while the latter are inferred from solar proxy and stellar evolution models. Since the Sun provides nearly all the energy driving the Earth’s climate system, changes in the sunlight reaching our planet can have - and have had - significant impacts on life and civilizations.Total solar irradiance has been measured from space since 1978 by a series of overlapping instruments. These have shown changes in the spatially- and spectrally-integrated radiant energy at the top of the Earth’s atmosphere from timescales as short as minutes to as long as a solar cycle. The Sun’s ~0.01% variations over a few minutes are caused by the superposition of convection and oscillations, and even occasionally by a large flare. Over days to weeks, changing surface activity affects solar brightness at the ~0.1% level. The 11-year solar cycle has comparable irradiance variations with peaks near solar maxima.Secular variations are harder to discern, being limited by instrument stability and the relatively short duration of the space-borne record. Proxy models of the Sun based on cosmogenic isotope records and inferred from Earth climate signatures indicate solar brightness changes over decades to millennia, although the magnitude of these variations depends on many assumptions. Stellar evolution affects yet longer timescales and is responsible for the greatest solar variabilities.In this talk I will summarize the Sun’s variability magnitudes over different temporal ranges, showing examples relevant for climate studies as well as detections of exo-solar planets transiting Sun-like stars.

  2. Inoculum development by using activated sludge to remove hydrogen sulphide (H2S through biofiltration* Desarrollo de un inóculo microbiano empleando lodos activados para la remoción de ácido sulfhídrico (H2S mediante biofiltración*

    Directory of Open Access Journals (Sweden)

    Carmona Salgado Yezid

    2005-12-01

    Full Text Available Different activated sludges were used for developing an inoculum able to degrade hydrogen sulphide in a pilot scale biofiltration plant using two different support materials: sugarcane bagasse and this bagasse mixed with pumice stone. Adapting and selecting microbial species which degrade hydrogen sulphide (H2S was aided by adding nutrients plus a specific substrate to the activated sludge. Population variation was monitored within the different trophic groups in the biofiter medium during pilot scale plant operation, a general trend towards sulphur-oxidising bacteria (SOB growth being observed as was a decrease in heterotrophic bacteria, molds and yeasts. The activated sludge which showed the highest substrate degradation speed was selected for standardising inoculum preparation; the different nutritional mediums were evaluated during this process. Measuring some variables for controlling the process led to choosing the pH for determining the proper point of inoculum adaptation for this specific substrate. The inoculation procedure and support characteristics in terms of establishing and developing the microbial species increased biofilter removal efficiency by up to 99% from start-up. Key words: biofilter, activated sludge, adapted microorganisms, sulphur-oxidising bacteria, respirometry. Este artículo es el resultado de un proyecto cofinanciado por Colciencias y desarrollado por un grupo de investigadores vinculados al proyecto a través de las entidades CorporaciónSe utilizaron lodos activados de diferentes orígenes para el desarrollo de un inóculo apto para la degradación de ácido sulfhídrico en un sistema piloto de biofiltración con dos unidades de diferentes materiales de soporte: bagazo de caña en un caso y una mezcla de este y piedra pómez en el otro. Mediante la adición a los lodos activados, de medio nutritivo con un sustrato específico, se favoreció el proceso de adaptación y selección de las especies

  3. Compact Spectrometers Based on Linear Variable Filters

    Data.gov (United States)

    National Aeronautics and Space Administration — Demonstrate a linear-variable spectrometer with an H2RG array. Linear Variable Filter (LVF) spectrometers provide attractive resource benefits – high optical...

  4. Eternity Variables to Prove Simulation of Specifications

    NARCIS (Netherlands)

    Hesselink, Wim H.

    2005-01-01

    Simulations of specifications are introduced as a unification and generalization of refinement mappings, history variables, forward simulations, prophecy variables, and backward simulations. A specification implements another specification if and only if there is a simulation from the first one to

  5. Variability through the Eyes of the Programmer

    DEFF Research Database (Denmark)

    Melo, Jean; Batista Narcizo, Fabricio; Hansen, Dan Witzner

    2017-01-01

    Preprocessor directives (#ifdefs) are often used to implement compile-time variability, despite the critique that they increase complexity, hamper maintainability, and impair code comprehensibility. Previous studies have shown that the time of bug finding increases linearly with variability. Howe...

  6. Scalable conditional induction variables (CIV) analysis

    KAUST Repository

    Oancea, Cosmin E.; Rauchwerger, Lawrence

    2015-01-01

    challenges to automatic parallelization. Because the complexity of such induction variables is often due to their conditional evaluation across the iteration space of loops we name them Conditional Induction Variables (CIV). This paper presents a flow

  7. Ordered random variables theory and applications

    CERN Document Server

    Shahbaz, Muhammad Qaiser; Hanif Shahbaz, Saman; Al-Zahrani, Bander M

    2016-01-01

    Ordered Random Variables have attracted several authors. The basic building block of Ordered Random Variables is Order Statistics which has several applications in extreme value theory and ordered estimation. The general model for ordered random variables, known as Generalized Order Statistics has been introduced relatively recently by Kamps (1995).

  8. SPATIAL VARIABILITY IN THE MUDPRAWN UPOGEBIA AFRICANA ...

    African Journals Online (AJOL)

    A nested sampling design was used to examine the variability in density, biomass, sex ratio and size of the estuarine mudprawn Upogebia africana in six estuaries on the south-east coast of South Africa. The objectives were to test the general hypothesis that there is variability in these variables at the scales of regions, ...

  9. Alongshore variability of nourished and natural beaches

    NARCIS (Netherlands)

    De Schipper, M.A.

    2014-01-01

    Alongshore variability in topography (i.e. height differences in bed level along the coast) can exist on both natural and nourished beaches. An important question prior to implementation of a nourishment project is how alongshore variability is going to evolve and, related to this variability, the

  10. Machine learning search for variable stars

    Science.gov (United States)

    Pashchenko, Ilya N.; Sokolovsky, Kirill V.; Gavras, Panagiotis

    2018-04-01

    Photometric variability detection is often considered as a hypothesis testing problem: an object is variable if the null hypothesis that its brightness is constant can be ruled out given the measurements and their uncertainties. The practical applicability of this approach is limited by uncorrected systematic errors. We propose a new variability detection technique sensitive to a wide range of variability types while being robust to outliers and underestimated measurement uncertainties. We consider variability detection as a classification problem that can be approached with machine learning. Logistic Regression (LR), Support Vector Machines (SVM), k Nearest Neighbours (kNN), Neural Nets (NN), Random Forests (RF), and Stochastic Gradient Boosting classifier (SGB) are applied to 18 features (variability indices) quantifying scatter and/or correlation between points in a light curve. We use a subset of Optical Gravitational Lensing Experiment phase two (OGLE-II) Large Magellanic Cloud (LMC) photometry (30 265 light curves) that was searched for variability using traditional methods (168 known variable objects) as the training set and then apply the NN to a new test set of 31 798 OGLE-II LMC light curves. Among 205 candidates selected in the test set, 178 are real variables, while 13 low-amplitude variables are new discoveries. The machine learning classifiers considered are found to be more efficient (select more variables and fewer false candidates) compared to traditional techniques using individual variability indices or their linear combination. The NN, SGB, SVM, and RF show a higher efficiency compared to LR and kNN.

  11. transformation of independent variables in polynomial regression ...

    African Journals Online (AJOL)

    Ada

    preferable when possible to work with a simple functional form in transformed variables rather than with a more complicated form in the original variables. In this paper, it is shown that linear transformations applied to independent variables in polynomial regression models affect the t ratio and hence the statistical ...

  12. Variable Pitch Darrieus Water Turbines

    Science.gov (United States)

    Kirke, Brian; Lazauskas, Leo

    In recent years the Darrieus wind turbine concept has been adapted for use in water, either as a hydrokinetic turbine converting the kinetic energy of a moving fluid in open flow like an underwater wind turbine, or in a low head or ducted arrangement where flow is confined, streamtube expansion is controlled and efficiency is not subject to the Betz limit. Conventional fixed pitch Darrieus turbines suffer from two drawbacks, (i) low starting torque and (ii) shaking due to cyclical variations in blade angle of attack. Ventilation and cavitation can also cause problems in water turbines when blade velocities are high. Shaking can be largely overcome by the use of helical blades, but these do not produce large starting torque. Variable pitch can produce high starting torque and high efficiency, and by suitable choice of pitch regime, shaking can be minimized but not entirely eliminated. Ventilation can be prevented by avoiding operation close to a free surface, and cavitation can be prevented by limiting blade velocities. This paper summarizes recent developments in Darrieus water turbines, some problems and some possible solutions.

  13. Anatomic variables affecting interdental papilla

    Directory of Open Access Journals (Sweden)

    Swapna A. Mahale

    2013-01-01

    Full Text Available Aim: The aim of this study is to evaluate the anatomic variables affecting the interdental papilla. Materials and Methods: Thirty adult patients were evaluated. Papilla score (PS, tooth form/shape, gingival thickness, crest bone height and keratinized gingiva/attached gingiva were recorded for 150 inter proximal sites. Data were analyzed using SPSS software package (version 7.0 and the significance level was set at 95% confidence interval. Pearson′s correlation was applied to correlate the relationship between the factors and the appearance of the papilla. Results: Competent papillae (complete fill interdentally were associated with: (1 Crown width (CW: length ≥0.87; (2 bone crest-contact point ≤5 mm; and (3 inter proximal gingival tissue thickness ≥1.5 mm. Gingival thickness correlated negatively with PS (r = −0.37 to −0.54 and positively with tissue height (r = 0.23-0.43. Tooth form (i.e., CW to length ratio correlated negatively with PS (r = −0.37 to −0.61. Conclusion: Gingival papilla appearance was associated significantly with tooth form/shape, crestal bone height and interproximal gingival thickness.

  14. Phytoscreening with SPME: Variability Analysis.

    Science.gov (United States)

    Limmer, Matt A; Burken, Joel G

    2015-01-01

    Phytoscreening has been demonstrated at a variety of sites over the past 15 years as a low-impact, sustainable tool in delineation of shallow groundwater contaminated with chlorinated solvents. Collection of tree cores is rapid and straightforward, but low concentrations in tree tissues requires sensitive analytics. Solid-phase microextraction (SPME) is amenable to the complex matrix while allowing for solvent-less extraction. Accurate quantification requires the absence of competitive sorption, examined here both in laboratory experiments and through comprehensive examination of field data. Analysis of approximately 2,000 trees at numerous field sites also allowed testing of the tree genus and diameter effects on measured tree contaminant concentrations. Collectively, while these variables were found to significantly affect site-adjusted perchloroethylene (PCE) concentrations, the explanatory power of these effects was small (adjusted R(2) = 0.031). 90th quantile chemical concentrations in trees were significantly reduced by increasing Henry's constant and increasing hydrophobicity. Analysis of replicate tree core data showed no correlation between replicate relative standard deviation (RSD) and wood type or tree diameter, with an overall median RSD of 30%. Collectively, these findings indicate SPME is an appropriate technique for sampling and analyzing chlorinated solvents in wood and that phytoscreening is robust against changes in tree type and diameter.

  15. Hidden Variables and Placebo Effects

    Science.gov (United States)

    Goradia, Shantilal

    2006-03-01

    God's response to prayers and placebo leads to a question. How does He respond deterministically? He may be controlling at least one of the two variables of the uncertainty principle by extending His invisible soul to each body particle locally. Amazingly, many Vedic verses support this answer. One describes the size of the soul as arithmetically matching the size of the nucleons as if a particle is a soul. One gives a name meaning particle soul (anu-atma), consistent with particle's indeterministic behavior like that of (soulful) bird’s flying in any directions irrespective of the direction of throw. One describes souls as eternal consistent with the conservation of baryon number. One links the souls to the omnipresent (param- atma) like Einstein Rosen bridges link particles to normal spacetime. One claims eternal coexistence of matter and soul as is inflationary universe in physics/0210040 V2. The implicit scientific consistency of such verses makes the relationship of particle source of consciousness to the omnipresent Supreme analogous to the relationship of quantum source of gravitons in my gr-qc/0507130 to normal spacetime This frees us from the postulation of quantum wormholes and quantum foam. Dr. Hooft's view in ``Does God play dice,'' Physicsword, Dec 2005 seems consistent with my progressive conference presentations in Russia, Europe, India, and USA (Hindu University) in 2004/05. I see implications for nanoscience.

  16. Envera Variable Compression Ratio Engine

    Energy Technology Data Exchange (ETDEWEB)

    Charles Mendler

    2011-03-15

    Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy has already demonstrated a degree of success, downsizing and fuel economy gains are currently limited. With new variable compression ratio technology however, the degree of engine downsizing and fuel economy improvement can be greatly increased. A small variable compression ratio (VCR) engine has the potential to return significantly higher vehicle fuel economy while also providing high power. Affordability and potential for near term commercialization are key attributes of the Envera VCR engine. VCR Technology To meet torque and power requirements, a smaller engine needs to do more work per stroke. This is typically accomplished by boosting the incoming charge with either a turbo or supercharger so that more energy is present in the cylinder per stroke to do the work. With current production engines the degree of engine boosting (which correlates to downsizing) is limited by detonation (combustion knock) at high boost levels. Additionally, the turbo or supercharger needs to be responsive and efficient while providing the needed boost. VCR technology eliminates the limitation of engine knock at high load levels by reducing compression ratio to {approx}9:1 (or whatever level is appropriate) when high boost pressures are needed. By reducing the compression ratio during high load demand periods there is increased volume in the cylinder at top dead center (TDC) which allows more charge (or energy) to be present in the cylinder without increasing the peak pressure. Cylinder pressure is thus kept below the level at which the engine would begin to knock. When loads on the engine are low

  17. Variable angle asymmetric cut monochromator

    International Nuclear Information System (INIS)

    Smither, R.K.; Fernandez, P.B.

    1993-09-01

    A variable incident angle, asymmetric cut, double crystal monochromator was tested for use on beamlines at the Advanced Photon Source (APS). For both undulator and wiggler beams the monochromator can expand area of footprint of beam on surface of the crystals to 50 times the area of incident beam; this will reduce the slope errors by a factor of 2500. The asymmetric cut allows one to increase the acceptance angle for incident radiation and obtain a better match to the opening angle of the incident beam. This can increase intensity of the diffracted beam by a factor of 2 to 5 and can make the beam more monochromatic, as well. The monochromator consists of two matched, asymmetric cut (18 degrees), silicon crystals mounted so that they can be rotated about three independent axes. Rotation around the first axis controls the Bragg angle. The second rotation axis is perpendicular to the diffraction planes and controls the increase of the area of the footprint of the beam on the crystal surface. Rotation around the third axis controls the angle between the surface of the crystal and the wider, horizontal axis for the beam and can make the footprint a rectangle with a minimum. length for this area. The asymmetric cut is 18 degrees for the matched pair of crystals, which allows one to expand the footprint area by a factor of 50 for Bragg angles up to 19.15 degrees (6 keV for Si[111] planes). This monochromator, with proper cooling, will be useful for analyzing the high intensity x-ray beams produced by both undulators and wigglers at the APS

  18. Heart rate variability and swimming.

    Science.gov (United States)

    Koenig, Julian; Jarczok, Marc N; Wasner, Mieke; Hillecke, Thomas K; Thayer, Julian F

    2014-10-01

    Professionals in the domain of swimming have a strong interest in implementing research methods in evaluating and improving training methods to maximize athletic performance and competitive outcome. Heart rate variability (HRV) has gained attention in research on sport and exercise to assess autonomic nervous system activity underlying physical activity and sports performance. Studies on swimming and HRV are rare. This review aims to summarize the current evidence on the application of HRV in swimming research and draws implications for future research. A systematic search of databases (PubMed via MEDLINE, PSYNDEX and Embase) according to the PRISMA statement was employed. Studies were screened for eligibility on inclusion criteria: (a) empirical investigation (HRV) in humans (non-clinical); (b) related to swimming; (c) peer-reviewed journal; and (d) English language. The search revealed 194 studies (duplicates removed), of which the abstract was screened for eligibility. Fourteen studies meeting the inclusion criteria were included in the review. Included studies broadly fell into three classes: (1) control group designs to investigate between-subject differences (i.e. swimmers vs. non-swimmers, swimmers vs. other athletes); (2) repeated measures designs on within-subject differences of interventional studies measuring HRV to address different modalities of training or recovery; and (3) other studies, on the agreement of HRV with other measures. The feasibility and possibilities of HRV within this particular field of application are well documented within the existing literature. Future studies, focusing on translational approaches that transfer current evidence in general practice (i.e. training of athletes) are needed.

  19. WIND VARIABILITY IN BZ CAMELOPARDALIS

    International Nuclear Information System (INIS)

    Honeycutt, R. K.; Kafka, S.; Robertson, J. W.

    2013-01-01

    Sequences of spectra of the nova-like cataclysmic variable (CV) BZ Cam were acquired on nine nights in 2005-2006 in order to study the time development of episodes of wind activity known to occur frequently in this star. We confirm the results of Ringwald and Naylor that the P-Cygni absorption components of the lines mostly evolve from higher expansion velocity to lower velocity as an episode progresses. We also commonly find blueshifted emission components in the Hα line profile, whose velocities and durations strongly suggest that they are also due to the wind. Curiously, Ringwald and Naylor reported common occurrences of redshifted Hα emission components in their BZ Cam spectra. We have attributed these emission components in Hα to occasions when gas concentrations in the bipolar wind (both front side and back side) become manifested as emission lines as they move beyond the disk's outer edge. We also suggest, based on changes in the P-Cygni profiles during an episode, that the progression from larger to smaller expansion velocities is due to the higher velocity portions of a wind concentration moving beyond the edge of the continuum light of the disk first, leaving a net redward shift of the remaining absorption profile. We derive a new orbital ephemeris for BZ Cam, using the radial velocity of the core of the He I λ5876 line, finding P = 0.15353(4). Using this period, the wind episodes in BZ Cam are found to be concentrated near the inferior conjunction of the emission line source. This result helps confirm that the winds in nova-like CVs are often phase dependent, in spite of the puzzling implication that such winds lack axisymmetry. We argue that the radiation-driven wind in BZ Cam receives an initial boost by acting on gas that has been lifted above the disk by the interaction of the accretion stream with the disk, thereby imposing flickering timescales onto the wind events, as well as leading to an orbital modulation of the wind due to the non

  20. Bedform response to flow variability

    Science.gov (United States)

    Nelson, J.M.; Logan, B.L.; Kinzel, P.J.; Shimizu, Y.; Giri, S.; Shreve, R.L.; McLean, S.R.

    2011-01-01

    Laboratory observations and computational results for the response of bedform fields to rapid variations in discharge are compared and discussed. The simple case considered here begins with a relatively low discharge over a flat bed on which bedforms are initiated, followed by a short high-flow period with double the original discharge, during which the morphology of the bedforms adjusts, followed in turn by a relatively long period of the original low discharge. For the grain size and hydraulic conditions selected, the Froude number remains subcritical during the experiment, and sediment moves predominantly as bedload. Observations show rapid development of quasi-two-dimensional bedforms during the initial period of low flow with increasing wavelength and height over the initial low-flow period. When the flow increases, the bedforms rapidly increase in wavelength and height, as expected from other empirical results. When the flow decreases back to the original discharge, the height of the bedforms quickly decreases in response, but the wavelength decreases much more slowly. Computational results using an unsteady two-dimensional flow model coupled to a disequilibrium bedload transport model for the same conditions simulate the formation and initial growth of the bedforms fairly accurately and also predict an increase in dimensions during the high-flow period. However, the computational model predicts a much slower rate of wavelength increase, and also performs less accurately during the final low-flow period, where the wavelength remains essentially constant, rather than decreasing. In addition, the numerical results show less variability in bedform wavelength and height than the measured values; the bedform shape is also somewhat different. Based on observations, these discrepancies may result from the simplified model for sediment particle step lengths used in the computational approach. Experiments show that the particle step length varies spatially and

  1. Climate change and climate variability impacts on rainfed agricultural activities and possible adaptation measures. A Mexican case study

    Energy Technology Data Exchange (ETDEWEB)

    Conde, C.; Ferrer, R. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico Circuito Exterior, Mexico, D.F. (Mexico)]. E-mail: e-mail: conde@servidor.unam.mx; Orozco, S. [Escuela de Agrobiologia, Universidad Autonoma de Tlaxcala, Tlaxcala (Mexico)

    2006-07-15

    Climate extreme events (such as those associated to strong El Nino events) highly affect Mexican agriculture, since more than sixty percent of it is rainfed. The basic crop cultivated is maize, which is still the main source of nutrients for a large portion of the rural population in the country. Within the project Capacity Building for Stage II Adaptation to Climate Change in Central America, Mexico and Cuba, we analyze the strategies developed by maize producers in the central region of the country to cope with climatic adverse events. Impact on rainfed maize due to climate variability and climate change conditions are studied using a crop simulation model. Several adaptation measures can be evaluated using that model. However, the effect of other stressors must be considered in an assessment of the adaptive capacity of small farmers to climate variability and change. Key stakeholders' involvement in the region helped us to decide which of the adaptive measures could be viable under the current conditions and under future climatic conditions. The construction of greenhouses, the use of compost, and dripping irrigation, were some of the techniques selected with the participation of the stakeholders. The enthusiastic responses to these measures allow us to consider that they can prevail in the future, under climate change conditions. However, the adaptation to climate change includes -besides the stated techniques- the generation of the capacities to cope with climatic adverse events, that is, to enhance the adaptive capacities to climate change among the key stakeholders. [Spanish] Los eventos climaticos extremos (como los asociados con eventos fuertes de El Nino) afectan de manera importante a la agricultura mexicana, ya que mas del sesenta por ciento de ella es de temporal, esto es, depende fundamentalmente de una buena temporada de lluvias para producir. El cultivo que se siembra es basicamente maiz, que todavia es la principal fuente de nutrientes para

  2. Variable-spot ion beam figuring

    International Nuclear Information System (INIS)

    Wu, Lixiang; Qiu, Keqiang; Fu, Shaojun

    2016-01-01

    This paper introduces a new scheme of ion beam figuring (IBF), or rather variable-spot IBF, which is conducted at a constant scanning velocity with variable-spot ion beam collimated by a variable diaphragm. It aims at improving the reachability and adaptation of the figuring process within the limits of machine dynamics by varying the ion beam spot size instead of the scanning velocity. In contrast to the dwell time algorithm in the conventional IBF, the variable-spot IBF adopts a new algorithm, which consists of the scan path programming and the trajectory optimization using pattern search. In this algorithm, instead of the dwell time, a new concept, integral etching time, is proposed to interpret the process of variable-spot IBF. We conducted simulations to verify its feasibility and practicality. The simulation results indicate the variable-spot IBF is a promising alternative to the conventional approach.

  3. Modeling the Variable Heliopause Location

    Science.gov (United States)

    Hensley, Kerry

    2018-03-01

    In 2012, Voyager 1 zipped across the heliopause. Five and a half years later, Voyager 2 still hasnt followed its twin into interstellar space. Can models of the heliopause location help determine why?How Far to the Heliopause?Artists conception of the heliosphere with the important structures and boundaries labeled. [NASA/Goddard/Walt Feimer]As our solar system travels through the galaxy, the solar outflow pushes against the surrounding interstellar medium, forming a bubble called the heliosphere. The edge of this bubble, the heliopause, is the outermost boundary of our solar system, where the solar wind and the interstellar medium meet. Since the solar outflow is highly variable, the heliopause is constantly moving with the motion driven by changes inthe Sun.NASAs twin Voyager spacecraft were poisedto cross the heliopause after completingtheir tour of the outer planets in the 1980s. In 2012, Voyager 1 registered a sharp increase in the density of interstellar particles, indicating that the spacecraft had passed out of the heliosphere and into the interstellar medium. The slower-moving Voyager 2 was set to pierce the heliopause along a different trajectory, but so far no measurements have shown that the spacecraft has bid farewell to oursolar system.In a recent study, ateam of scientists led by Haruichi Washimi (Kyushu University, Japan and CSPAR, University of Alabama-Huntsville) argues that models of the heliosphere can help explain this behavior. Because the heliopause location is controlled by factors that vary on many spatial and temporal scales, Washimiand collaborators turn to three-dimensional, time-dependent magnetohydrodynamics simulations of the heliosphere. In particular, they investigate how the position of the heliopause along the trajectories of Voyager 1 and Voyager 2 changes over time.Modeled location of the heliopause along the paths of Voyagers 1 (blue) and 2 (orange). Click for a closer look. The red star indicates the location at which Voyager

  4. Concurrent variable-interval variable-ratio schedules in a dynamic choice environment.

    Science.gov (United States)

    Bell, Matthew C; Baum, William M

    2017-11-01

    Most studies of operant choice have focused on presenting subjects with a fixed pair of schedules across many experimental sessions. Using these methods, studies of concurrent variable- interval variable-ratio schedules helped to evaluate theories of choice. More recently, a growing literature has focused on dynamic choice behavior. Those dynamic choice studies have analyzed behavior on a number of different time scales using concurrent variable-interval schedules. Following the dynamic choice approach, the present experiment examined performance on concurrent variable-interval variable-ratio schedules in a rapidly changing environment. Our objectives were to compare performance on concurrent variable-interval variable-ratio schedules with extant data on concurrent variable-interval variable-interval schedules using a dynamic choice procedure and to extend earlier work on concurrent variable-interval variable-ratio schedules. We analyzed performances at different time scales, finding strong similarities between concurrent variable-interval variable-interval and concurrent variable-interval variable- ratio performance within dynamic choice procedures. Time-based measures revealed almost identical performance in the two procedures compared with response-based measures, supporting the view that choice is best understood as time allocation. Performance at the smaller time scale of visits accorded with the tendency seen in earlier research toward developing a pattern of strong preference for and long visits to the richer alternative paired with brief "samples" at the leaner alternative ("fix and sample"). © 2017 Society for the Experimental Analysis of Behavior.

  5. Latent variables and route choice behavior

    DEFF Research Database (Denmark)

    Prato, Carlo Giacomo; Bekhor, Shlomo; Pronello, Cristina

    2012-01-01

    In the last decade, a broad array of disciplines has shown a general interest in enhancing discrete choice models by considering the incorporation of psychological factors affecting decision making. This paper provides insight into the comprehension of the determinants of route choice behavior...... and bound algorithm. A hybrid model consists of measurement equations, which relate latent variables to measurement indicators and utilities to choice indicators, and structural equations, which link travelers’ observable characteristics to latent variables and explanatory variables to utilities. Estimation...

  6. Reward-dependent modulation of movement variability.

    Science.gov (United States)

    Pekny, Sarah E; Izawa, Jun; Shadmehr, Reza

    2015-03-04

    Movement variability is often considered an unwanted byproduct of a noisy nervous system. However, variability can signal a form of implicit exploration, indicating that the nervous system is intentionally varying the motor commands in search of actions that yield the greatest success. Here, we investigated the role of the human basal ganglia in controlling reward-dependent motor variability as measured by trial-to-trial changes in performance during a reaching task. We designed an experiment in which the only performance feedback was success or failure and quantified how reach variability was modulated as a function of the probability of reward. In healthy controls, reach variability increased as the probability of reward decreased. Control of variability depended on the history of past rewards, with the largest trial-to-trial changes occurring immediately after an unrewarded trial. In contrast, in participants with Parkinson's disease, a known example of basal ganglia dysfunction, reward was a poor modulator of variability; that is, the patients showed an impaired ability to increase variability in response to decreases in the probability of reward. This was despite the fact that, after rewarded trials, reach variability in the patients was comparable to healthy controls. In summary, we found that movement variability is partially a form of exploration driven by the recent history of rewards. When the function of the human basal ganglia is compromised, the reward-dependent control of movement variability is impaired, particularly affecting the ability to increase variability after unsuccessful outcomes. Copyright © 2015 the authors 0270-6474/15/354015-10$15.00/0.

  7. Millijansky radio variability in SDSS stripe 82

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, J. A.; Becker, R. H. [University of California, 1 Shields Avenue, Davis, CA 95616 (United States); White, R. L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Richards, G. T., E-mail: hodge@mpia.de [Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States)

    2013-06-01

    We report on a blind survey for extragalactic radio variability that was carried out by comparing two epochs of data from the Faint Images of the Radio Sky at Twenty centimeters survey with a third epoch from a new 1.4 GHz survey of SDSS Stripe 82. The three epochs are spaced seven years apart and have an overlapping area of 60 deg{sup 2}. We uncover 89 variable sources down to the millijansky level, 75 of which are newly identified, and we find no evidence for transient phenomena. This new sample of variable sources allows us to infer an upper limit to the mean characteristic timescale of active galactic nucleus radio variability of 14 yr. We find that only 1% of extragalactic sources have fractional variability f {sub var} > 3, while 44% of Galactic sources vary by this much. The variable sample contains a larger fraction of quasars than a comparable non-variable control sample, though the majority of the variable sources appear to be extended galaxies in the optical. This implies that either quasars are not the dominant contributor to the variability of the sample, or that the deep optical data allow us to detect the host galaxies of some low-z quasars. We use the new, higher resolution data to report on the morphology of the variable sources. Finally, we show that the fraction of sources that are variable remains constant or increases at low flux densities. This may imply that next generation radio surveys with telescopes like Australian Square Kilometer Array Pathfinder and MeerKAT will see a constant or even increasing fraction of variable sources down into the sub-millijansky regime.

  8. Eccentric crank variable compression ratio mechanism

    Science.gov (United States)

    Lawrence, Keith Edward [Kobe, JP; Moser, William Elliott [Peoria, IL; Roozenboom, Stephan Donald [Washington, IL; Knox, Kevin Jay [Peoria, IL

    2008-05-13

    A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

  9. Exchange rate variability, market activity and heterogeneity

    OpenAIRE

    Rime, Dagfinn; Sucarrat, Genaro

    2007-01-01

    We study the role played by geographic and bank-size heterogeneity in the relation between exchange rate variability and market activity. We find some support for the hypothesis that increases in short-term global interbank market activity, which can be interpreted as due to variation in information arrival, increase variability. However, our results do not suggest that local short-term activity increases variability. With respect to long-term market activity, which can be interpreted as a me...

  10. Variable Speed Rotor System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Variable speed rotors will give helicopters several advantages: higher top speed, greater fuel efficiency, momentary emergency over-power, resonance detuning...

  11. A Framework for Categorizing Important Project Variables

    Science.gov (United States)

    Parsons, Vickie S.

    2003-01-01

    While substantial research has led to theories concerning the variables that affect project success, no universal set of such variables has been acknowledged as the standard. The identification of a specific set of controllable variables is needed to minimize project failure. Much has been hypothesized about the need to match project controls and management processes to individual projects in order to increase the chance for success. However, an accepted taxonomy for facilitating this matching process does not exist. This paper surveyed existing literature on classification of project variables. After an analysis of those proposals, a simplified categorization is offered to encourage further research.

  12. Variable and subset selection in PLS regression

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    2001-01-01

    The purpose of this paper is to present some useful methods for introductory analysis of variables and subsets in relation to PLS regression. We present here methods that are efficient in finding the appropriate variables or subset to use in the PLS regression. The general conclusion...... is that variable selection is important for successful analysis of chemometric data. An important aspect of the results presented is that lack of variable selection can spoil the PLS regression, and that cross-validation measures using a test set can show larger variation, when we use different subsets of X, than...

  13. Gaia DR2 documentation Chapter 7: Variability

    Science.gov (United States)

    Eyer, L.; Guy, L.; Distefano, E.; Clementini, G.; Mowlavi, N.; Rimoldini, L.; Roelens, M.; Audard, M.; Holl, B.; Lanzafame, A.; Lebzelter, T.; Lecoeur-Taïbi, I.; Molnár, L.; Ripepi, V.; Sarro, L.; Jevardat de Fombelle, G.; Nienartowicz, K.; De Ridder, J.; Juhász, Á.; Molinaro, R.; Plachy, E.; Regibo, S.

    2018-04-01

    This chapter of the Gaia DR2 documentation describes the models and methods used on the 22 months of data to produce the Gaia variable star results for Gaia DR2. The variability processing and analysis was based mostly on the calibrated G and integrated BP and RP photometry. The variability analysis approach to the Gaia data has been described in Eyer et al. (2017), and the Gaia DR2 results are presented in Holl et al. (2018). Detailed methods on specific topics will be published in a number of separate articles. Variability behaviour in the colour magnitude diagram is presented in Gaia Collaboration et al. (2018c).

  14. Variable-Period Undulators for Synchrotron Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

    2005-02-22

    A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

  15. Variable-Period Undulators For Synchrotron Radiation

    Science.gov (United States)

    Shenoy, Gopal; Lewellen, John; Shu, Deming; Vinokurov, Nikolai

    2005-02-22

    A new and improved undulator design is provided that enables a variable period length for the production of synchrotron radiation from both medium-energy and high-energy storage rings. The variable period length is achieved using a staggered array of pole pieces made up of high permeability material, permanent magnet material, or an electromagnetic structure. The pole pieces are separated by a variable width space. The sum of the variable width space and the pole width would therefore define the period of the undulator. Features and advantages of the invention include broad photon energy tunability, constant power operation and constant brilliance operation.

  16. The WFCAM multiwavelength Variable Star Catalog

    Science.gov (United States)

    Ferreira Lopes, C. E.; Dékány, I.; Catelan, M.; Cross, N. J. G.; Angeloni, R.; Leão, I. C.; De Medeiros, J. R.

    2015-01-01

    Context. Stellar variability in the near-infrared (NIR) remains largely unexplored. The exploitation of public science archives with data-mining methods offers a perspective for a time-domain exploration of the NIR sky. Aims: We perform a comprehensive search for stellar variability using the optical-NIR multiband photometric data in the public Calibration Database of the WFCAM Science Archive (WSA), with the aim of contributing to the general census of variable stars and of extending the current scarce inventory of accurate NIR light curves for a number of variable star classes. Methods: Standard data-mining methods were applied to extract and fine-tune time-series data from the WSA. We introduced new variability indices designed for multiband data with correlated sampling, and applied them for preselecting variable star candidates, i.e., light curves that are dominated by correlated variations, from noise-dominated ones. Preselection criteria were established by robust numerical tests for evaluating the response of variability indices to the colored noise characteristic of the data. We performed a period search using the string-length minimization method on an initial catalog of 6551 variable star candidates preselected by variability indices. Further frequency analysis was performed on positive candidates using three additional methods in combination, in order to cope with aliasing. Results: We find 275 periodic variable stars and an additional 44 objects with suspected variability with uncertain periods or apparently aperiodic variation. Only 44 of these objects had been previously known, including 11 RR Lyrae stars on the outskirts of the globular cluster M 3 (NGC 5272). We provide a preliminary classification of the new variable stars that have well-measured light curves, but the variability types of a large number of objects remain ambiguous. We classify most of the new variables as contact binary stars, but we also find several pulsating stars, among which

  17. (Super Variable Costing-Throughput Costing)

    OpenAIRE

    Çakıcı, Cemal

    2006-01-01

    (Super Variable Costing-Throughput Costing) The aim of this study is to explain the super-variable costing method which is a new subject in cost and management accounting and to show it’s working practicly.Shortly, super-variable costing can be defined as a costing method which is use only direct material costs in calculate of product costs and treats all costs except these (direct labor and overhead) as periad costs or operating costs.By using super-variable costing method, product costs ar...

  18. THE CHANDRA VARIABLE GUIDE STAR CATALOG

    International Nuclear Information System (INIS)

    Nichols, Joy S.; Lauer, Jennifer L.; Morgan, Douglas L.; Sundheim, Beth A.; Henden, Arne A.; Huenemoerder, David P.; Martin, Eric

    2010-01-01

    Variable stars have been identified among the optical-wavelength light curves of guide stars used for pointing control of the Chandra X-ray Observatory. We present a catalog of these variable stars along with their light curves and ancillary data. Variability was detected to a lower limit of 0.02 mag amplitude in the 4000-10000 A range using the photometrically stable Aspect Camera on board the Chandra spacecraft. The Chandra Variable Guide Star Catalog (VGUIDE) contains 827 stars, of which 586 are classified as definitely variable and 241 are identified as possibly variable. Of the 586 definite variable stars, we believe 319 are new variable star identifications. Types of variables in the catalog include eclipsing binaries, pulsating stars, and rotating stars. The variability was detected during the course of normal verification of each Chandra pointing and results from analysis of over 75,000 guide star light curves from the Chandra mission. The VGUIDE catalog represents data from only about 9 years of the Chandra mission. Future releases of VGUIDE will include newly identified variable guide stars as the mission proceeds. An important advantage of the use of space data to identify and analyze variable stars is the relatively long observations that are available. The Chandra orbit allows for observations up to 2 days in length. Also, guide stars were often used multiple times for Chandra observations, so many of the stars in the VGUIDE catalog have multiple light curves available from various times in the mission. The catalog is presented as both online data associated with this paper and as a public Web interface. Light curves with data at the instrumental time resolution of about 2 s, overplotted with the data binned at 1 ks, can be viewed on the public Web interface and downloaded for further analysis. VGUIDE is a unique project using data collected during the mission that would otherwise be ignored. The stars available for use as Chandra guide stars are

  19. The Chandra Source Catalog: Source Variability

    Science.gov (United States)

    Nowak, Michael; Rots, A. H.; McCollough, M. L.; Primini, F. A.; Glotfelty, K. J.; Bonaventura, N. R.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Evans, J. D.; Evans, I.; Fabbiano, G.; Galle, E. C.; Gibbs, D. G., II; Grier, J. D.; Hain, R.; Hall, D. M.; Harbo, P. N.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Plummer, D. A.; Refsdal, B. L.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; van Stone, D. W.; Winkelman, S. L.; Zografou, P.

    2009-09-01

    The Chandra Source Catalog (CSC) contains fields of view that have been studied with individual, uninterrupted observations that span integration times ranging from 1 ksec to 160 ksec, and a large number of which have received (multiple) repeat observations days to years later. The CSC thus offers an unprecedented look at the variability of the X-ray sky over a broad range of time scales, and across a wide diversity of variable X-ray sources: stars in the local galactic neighborhood, galactic and extragalactic X-ray binaries, Active Galactic Nuclei, etc. Here we describe the methods used to identify and quantify source variability within a single observation, and the methods used to assess the variability of a source when detected in multiple, individual observations. Three tests are used to detect source variability within a single observation: the Kolmogorov-Smirnov test and its variant, the Kuiper test, and a Bayesian approach originally suggested by Gregory and Loredo. The latter test not only provides an indicator of variability, but is also used to create a best estimate of the variable lightcurve shape. We assess the performance of these tests via simulation of statistically stationary, variable processes with arbitrary input power spectral densities (here we concentrate on results of red noise simulations) at variety of mean count rates and fractional root mean square variabilities relevant to CSC sources. We also assess the false positive rate via simulations of constant sources whose sole source of fluctuation is Poisson noise. We compare these simulations to an assessment of the variability found in real CSC sources, and estimate the variability sensitivities of the CSC.

  20. Variability of BL Lacertae type object

    Energy Technology Data Exchange (ETDEWEB)

    Cayatte, V

    1987-10-01

    This object is among the brightest and the most violently variable of this galaxy class with active nuclei. It has been studied in many wavelength domains and in polarimetry. Some important results are reported here and more particularly on its variability. These observations bring some elements for a better knowledge of the inner source.

  1. Convex trace functions of several variables

    DEFF Research Database (Denmark)

    Hansen, Frank

    2002-01-01

    We prove that the function (x1,...,xk)¿Tr(f(x1,...,xk)), defined on k-tuples of symmetric matrices of order (n1,...,nk) in the domain of f, is convex for any convex function f of k variables. The matrix f(x1,...,xk) is defined by the functional calculus for functions of several variables, and it ...

  2. Variable orifice using an iris shutter

    International Nuclear Information System (INIS)

    Beeman, R.; Brajkovich, S.J.

    1978-01-01

    A variable orifice forming mechanism is described that utilizes shutter arrangement adapted to control gas flow, conductance in vacuum systems, as a heat shield for furnace windows, as a beam shutter in sputtering operations, and in any other application requiring periodic or continuously-variable control of material, gas, or fluid flow

  3. Short-timescale variability in cataclysmic binaries

    International Nuclear Information System (INIS)

    Cordova, F.A.; Mason, K.O.

    1982-01-01

    Rapid variability, including flickering and pulsations, has been detected in cataclysmic binaries at optical and x-ray frequencies. In the case of the novalike variable TT Arietis, simultaneous observations reveal that the x-ray and optical flickering activity is strongly correlated, while short period pulsations are observed that occur at the same frequencies in both wavelength bands

  4. Learning dynamic Bayesian networks with mixed variables

    DEFF Research Database (Denmark)

    Bøttcher, Susanne Gammelgaard

    This paper considers dynamic Bayesian networks for discrete and continuous variables. We only treat the case, where the distribution of the variables is conditional Gaussian. We show how to learn the parameters and structure of a dynamic Bayesian network and also how the Markov order can be learned...

  5. Latent variable models are network models.

    Science.gov (United States)

    Molenaar, Peter C M

    2010-06-01

    Cramer et al. present an original and interesting network perspective on comorbidity and contrast this perspective with a more traditional interpretation of comorbidity in terms of latent variable theory. My commentary focuses on the relationship between the two perspectives; that is, it aims to qualify the presumed contrast between interpretations in terms of networks and latent variables.

  6. Psychological and Educational Variables in University Dropout

    Science.gov (United States)

    Bethencourt, Jose Tomas; Cabrera, Lidia; Hernandez, Juan Andres; Alvarez-Perez, Pedro; Gonzalez-Afonso, Miriam

    2008-01-01

    Introduction: The purpose of this research is to demonstrate that on the perceptions of university students, the student variables are seen as most important than the context variables to dropout their university studies. Method: The used methodology was cross-sectional or of cut, of retrospective type. 558 undergraduates were interviewed by…

  7. Investigating Reliabilities of Intraindividual Variability Indicators

    Science.gov (United States)

    Wang, Lijuan; Grimm, Kevin J.

    2012-01-01

    Reliabilities of the two most widely used intraindividual variability indicators, "ISD[superscript 2]" and "ISD", are derived analytically. Both are functions of the sizes of the first and second moments of true intraindividual variability, the size of the measurement error variance, and the number of assessments within a burst. For comparison,…

  8. Quantification of variability in bedform geometry

    NARCIS (Netherlands)

    van der Mark, C.F.; Blom, Astrid; Hulscher, Suzanne J.M.H.

    2008-01-01

    We analyze the variability in bedform geometry in laboratory and field studies. Even under controlled steady flow conditions in laboratory flumes, bedforms are irregular in size, shape, and spacing, also in case of well-sorted sediment. Our purpose is to quantify the variability in bedform geometry.

  9. Precipitation variability increases in a warmer climate.

    Science.gov (United States)

    Pendergrass, Angeline G; Knutti, Reto; Lehner, Flavio; Deser, Clara; Sanderson, Benjamin M

    2017-12-21

    Understanding changes in precipitation variability is essential for a complete explanation of the hydrologic cycle's response to warming and its impacts. While changes in mean and extreme precipitation have been studied intensively, precipitation variability has received less attention, despite its theoretical and practical importance. Here, we show that precipitation variability in most climate models increases over a majority of global land area in response to warming (66% of land has a robust increase in variability of seasonal-mean precipitation). Comparing recent decades to RCP8.5 projections for the end of the 21 st century, we find that in the global, multi-model mean, precipitation variability increases 3-4% K -1 globally, 4-5% K -1 over land and 2-4% K -1 over ocean, and is remarkably robust on a range of timescales from daily to decadal. Precipitation variability increases by at least as much as mean precipitation and less than moisture and extreme precipitation for most models, regions, and timescales. We interpret this as being related to an increase in moisture which is partially mitigated by weakening circulation. We show that changes in observed daily variability in station data are consistent with increased variability.

  10. Precipitation variability assessment of northeast China: Songhua

    Indian Academy of Sciences (India)

    Variability in precipitation is critical for the management of water resources. In this study, the researchentropy base concept was applied to investigate spatial and temporal variability of the precipitationduring 1964–2013 in the Songhua River basin of Heilongjiang Province in China. Sample entropy wasapplied on ...

  11. Cartas de control para monitorear variables multinomiales

    Directory of Open Access Journals (Sweden)

    Luz Marcela Restrepo-Tamayo

    2014-07-01

    Full Text Available Background: The control as a tool for monitoring the quality of a product, allows to study the stability of processes over time, contrasting two hypothesis, which states that the process is in stable condition and the other denies it. Its use has been massive for continuous variables but not for categorical variables, why it is imperative to design such tools for such variables. Objective: To propose two (2 control charts for variables multinomial processes based on the p-value test result for homogeneity of proportions using the chi square test for uniform processing variables and approximation Wilson - Hilferty for variables chi square. Methods: The performance of proposed charts via simulation is estimated considering a Phase II process and considering the first category increments of 2%, 4% and 6% in the control stage. Results: The multinomial control chart using Wilson-Hilferty approximation for variables chi square, from the transformation of value-p, has poor performance compared to the control charts using p-value processing and using chi-square p-value, as they have less ability to detect small changes. Conclusion: We propose two control charts to monitor multinomial variables and once studied via simulation, based on the average run length (ARL and the probability of rejecting the null hypothesis of equal proportions, we recommend the control chart using value-p, or equivalently, the control chart processing using chi square p-value.

  12. Hidden variables and locality in quantum theory

    International Nuclear Information System (INIS)

    Shiva, Vandana.

    1978-12-01

    The status of hidden variables in quantum theory has been debated since the 1920s. The author examines the no-hidden-variable theories of von Neumann, Kochen, Specker and Bell, and finds that they all share one basic assumption: averaging over the hidden variables should reproduce the quantum mechanical probabilities. Von Neumann also makes a linearity assumption, Kochen and Specker require the preservation of certain functional relations between magnitudes, and Bell proposes a locality condition. It has been assumed that the extrastatistical requirements are needed to serve as criteria of success for the introduction of hidden variables because the statistical condition is trivially satisfied, and that Bell's result is based on a locality condition that is physically motivated. The author shows that the requirement of weak locality, which is not physically motivated, is enough to give Bell's result. The proof of Bell's inequality works equally well for any pair of commuting magnitudes satisfying a condition called the degeneracy principle. None of the no-hidden-variable proofs apply to a class of hidden variable theories that are not phase-space reconstructions of quantum mechanics. The author discusses one of these theories, the Bohm-Bub theory, and finds that hidden variable theories that re all the quantum statistics, for single and sequential measurements, must introduce a randomization process for the hidden variables after each measurement. The philosophical significance of this theory lies in the role it can play in solving the conceptual puzzles posed by quantum theory

  13. Variable Thermal Conductivity on Compressible Boundary Layer ...

    African Journals Online (AJOL)

    In this paper, variable thermal conductivity on heat transfer over a circular cylinder is presented. The concept of assuming constant thermal conductivity on materials is however not efficient. Hence, the governing partial differential equation is reduced using non-dimensionless variables into a system of coupled non-linear ...

  14. [Resonance hypothesis of heart rate variability origin].

    Science.gov (United States)

    Sheĭkh-Zade, Iu R; Mukhambetaliev, G Kh; Cherednik, I L

    2009-09-01

    A hypothesis is advanced of the heart rate variability being subjected to beat-to-beat regulation of cardiac cycle duration in order to ensure the resonance interaction between respiratory and own fluctuation of the arterial system volume for minimization of power expenses of cardiorespiratory system. Myogenic, parasympathetic and sympathetic machanisms of heart rate variability are described.

  15. Mastery Learning and the Decreasing Variability Hypothesis.

    Science.gov (United States)

    Livingston, Jennifer A.; Gentile, J. Ronald

    1996-01-01

    This report results from studies that tested two variations of Bloom's decreasing variability hypothesis using performance on successive units of achievement in four graduate classrooms that used mastery learning procedures. Data do not support the decreasing variability hypothesis; rather, they show no change over time. (SM)

  16. Reinforcement and Induction of Operant Variability

    Science.gov (United States)

    Neuringer, Allen

    2012-01-01

    The target paper by Barba (2012) raises issues that were the focus of the author's first two publications on operant variability. The author will describe the main findings in those papers and then discuss Barba's specific arguments. Barba has argued against the operant nature of variability. (Contains 2 figures.)

  17. Zone edge effects with variable rate irrigation

    Science.gov (United States)

    Variable rate irrigation (VRI) systems may offer solutions to enhance water use efficiency by addressing variability within a field. However, the design of VRI systems should be considered to maximize application uniformity within sprinkler zones, while minimizing edge effects between such zones alo...

  18. Climatological variability in regional air pollution

    International Nuclear Information System (INIS)

    Shannon, J.D.; Trexler, E.C. Jr.

    1995-01-01

    Although some air pollution modeling studies examine events that have already occurred (e.g., the Chernobyl plume) with relevant meteorological conditions largely known, most pollution modeling studies address expected or potential scenarios for the future. Future meteorological conditions, the major pollutant forcing function other than emissions, are inherently uncertain although much relevant information is contained in past observational data. For convenience in our discussions of regional pollutant variability unrelated to emission changes, we define meteorological variability as short-term (within-season) pollutant variability and climatological variability as year-to-year changes in seasonal averages and accumulations of pollutant variables. In observations and in some of our simulations the effects are confounded because for seasons of two different years both the mean and the within-season character of a pollutant variable may change. Effects of climatological and meteorological variability on means and distributions of air pollution parameters, particularly those related to regional visibility, are illustrated. Over periods of up to a decade climatological variability may mask or overstate improvements resulting from emission controls. The importance of including climatological uncertainties in assessing potential policies, particularly when based partly on calculated source-receptor relationships, is highlighted

  19. Practical evaluation of action-angle variables

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1984-02-01

    A practical method is described for establishing action-angle variables for a Hamiltonian system. That is, a given nearly integrable Hamiltonian is divided into an exactly integrable system plus a perturbation in action-angle form. The transformation of variables, which is carried out using a few short trajectory integrations, permits a rapid determination of trajectory properties throughout a phase space volume

  20. Phase space dynamics and collective variable fluctuations

    International Nuclear Information System (INIS)

    Benhassine, B.; Farine, M.; Idier, D.; Remaud, B.; Sebille, F.; Schuck, P.

    1995-01-01

    A dynamical study of collective variable fluctuations in heavy ion reactions is performed within the framework of the Boltzmann-Langevin theory. A general method to extract dispersions on collective variables from numerical simulations based on test particles models is presented and its validity is checked by comparison with analytical equilibrium results. (authors)

  1. Phase space dynamics and collective variable fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Benhassine, B.; Farine, M.; Idier, D.; Remaud, B.; Sebille, F. [Laboratoire de Physique Nucleaire de Nantes, 44 (France); Schuck, P. [Institut des Sciences Nucleaires, 38 - Grenoble (France)

    1995-12-31

    A dynamical study of collective variable fluctuations in heavy ion reactions is performed within the framework of the Boltzmann-Langevin theory. A general method to extract dispersions on collective variables from numerical simulations based on test particles models is presented and its validity is checked by comparison with analytical equilibrium results. (authors) 10 refs.

  2. Environmental variables, pesticide pollution and meiofaunal ...

    African Journals Online (AJOL)

    Due to the much smaller catchment of the Rooiels Estuary, many environmental variables were significantly different (p< 0.001) from the variables in the Lourens Estuary, e.g. salinity, temperature, pH, total suspended solids, nitrate and depth. No pesticide concentrations were expected in the Rooiels Estuary due

  3. Ecosystem variability in west Greenland waters

    DEFF Research Database (Denmark)

    Buch, E.; Pedersen, Søren Anker; Ribergaard, M. H.

    2004-01-01

    A review of the climate conditions off West Greenland during the past 50 years shows large variability in the atmospheric, oceanographic and sea-ice variables, as well as in fish stocks. A positive relationship is found between water temperature and the recruitment of cod and redfish, whereas the...

  4. Continuous Variable Quantum Communication and Computation

    DEFF Research Database (Denmark)

    Andersen, Ulrik Lund; Dong, Ruifang; Jezek, Miroslav

    2011-01-01

    We use squeezed states of light to implement a robust continuous variable quantum key distribution scheme and an optical Hadamard gate based on coherent state qubits.......We use squeezed states of light to implement a robust continuous variable quantum key distribution scheme and an optical Hadamard gate based on coherent state qubits....

  5. Confounding of three binary-variables counterfactual model

    OpenAIRE

    Liu, Jingwei; Hu, Shuang

    2011-01-01

    Confounding of three binary-variables counterfactual model is discussed in this paper. According to the effect between the control variable and the covariate variable, we investigate three counterfactual models: the control variable is independent of the covariate variable, the control variable has the effect on the covariate variable and the covariate variable affects the control variable. Using the ancillary information based on conditional independence hypotheses, the sufficient conditions...

  6. The variable stars of NGC 1866

    International Nuclear Information System (INIS)

    Welch, D.L.; Cote, P.; Fischer, P.; Mateo, M.; Madore, B.F.

    1991-01-01

    A search has been conducted for new variables in the LMC cluster NGC 1866 using new multiepoch CCD photometry. Eight previously unknown Cepheid variables, most near the cluster core, are found. Of the new variables reported by Storm et al. (188), only six of 10 appear to be Cepheids and one of these is not a member. Periods and mean magnitudes and colors for sufficiently uncrowded variables are reported, as is one red giant variable of long period and one Cepheid which is a single-lined spectroscopic binary with a velocity semiamplitude greater than or equal to 10.5 km/s. The variation of light-curve amplitude with position in the instability strip is reported along with an apparently nonvariable star, which is a radial velocity member, in the strip. A true distance modulus of 18.57 + or - 0.01 mag is obtained for the cluster. 36 refs

  7. Quantum engineering of continuous variable quantum states

    International Nuclear Information System (INIS)

    Sabuncu, Metin

    2009-01-01

    Quantum information with continuous variables is a field attracting increasing attention recently. In continuous variable quantum information one makes use of the continuous information encoded into the quadrature of a quantized light field instead of binary quantities such as the polarization state of a single photon. This brand new research area is witnessing exciting theoretical and experimental achievements such as teleportation, quantum computation and quantum error correction. The rapid development of the field is mainly due higher optical data rates and the availability of simple and efficient manipulation tools in continuous-variable quantum information processing. We in this thesis extend the work in continuous variable quantum information processing and report on novel experiments on amplification, cloning, minimal disturbance and noise erasure protocols. The promising results we obtain in these pioneering experiments indicate that the future of continuous variable quantum information is bright and many advances can be foreseen. (orig.)

  8. Quantum engineering of continuous variable quantum states

    Energy Technology Data Exchange (ETDEWEB)

    Sabuncu, Metin

    2009-10-29

    Quantum information with continuous variables is a field attracting increasing attention recently. In continuous variable quantum information one makes use of the continuous information encoded into the quadrature of a quantized light field instead of binary quantities such as the polarization state of a single photon. This brand new research area is witnessing exciting theoretical and experimental achievements such as teleportation, quantum computation and quantum error correction. The rapid development of the field is mainly due higher optical data rates and the availability of simple and efficient manipulation tools in continuous-variable quantum information processing. We in this thesis extend the work in continuous variable quantum information processing and report on novel experiments on amplification, cloning, minimal disturbance and noise erasure protocols. The promising results we obtain in these pioneering experiments indicate that the future of continuous variable quantum information is bright and many advances can be foreseen. (orig.)

  9. Continuous-variable quantum homomorphic signature

    Science.gov (United States)

    Li, Ke; Shang, Tao; Liu, Jian-wei

    2017-10-01

    Quantum cryptography is believed to be unconditionally secure because its security is ensured by physical laws rather than computational complexity. According to spectrum characteristic, quantum information can be classified into two categories, namely discrete variables and continuous variables. Continuous-variable quantum protocols have gained much attention for their ability to transmit more information with lower cost. To verify the identities of different data sources in a quantum network, we propose a continuous-variable quantum homomorphic signature scheme. It is based on continuous-variable entanglement swapping and provides additive and subtractive homomorphism. Security analysis shows the proposed scheme is secure against replay, forgery and repudiation. Even under nonideal conditions, it supports effective verification within a certain verification threshold.

  10. The Taiwanese-American occultation survey project stellar variability. III. Detection of 58 new variable stars

    Energy Technology Data Exchange (ETDEWEB)

    Ishioka, R.; Wang, S.-Y.; Zhang, Z.-W.; Lehner, M. J.; Cook, K. H.; King, S.-K.; Lee, T.; Marshall, S. L.; Schwamb, M. E.; Wang, J.-H.; Wen, C.-Y. [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Alcock, C.; Protopapas, P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Axelrod, T. [Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721 (United States); Bianco, F. B. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Byun, Y.-I. [Department of Astronomy and University Observatory, Yonsei University, 134 Shinchon, Seoul 120-749 (Korea, Republic of); Chen, W. P.; Ngeow, C.-C. [Institute of Astronomy, National Central University, No. 300, Jhongda Road, Jhongli City, Taoyuan County 320, Taiwan (China); Kim, D.-W. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Rice, J. A., E-mail: ishioka@asiaa.sinica.edu.tw [Department of Statistics, University of California Berkeley, 367 Evans Hall, Berkeley, CA 94720 (United States)

    2014-04-01

    The Taiwanese-American Occultation Survey project is designed for the detection of stellar occultations by small-size Kuiper Belt Objects, and it has monitored selected fields along the ecliptic plane by using four telescopes with a 3 deg{sup 2} field of view on the sky since 2005. We have analyzed data accumulated during 2005-2012 to detect variable stars. Sixteen fields with observations of more than 100 epochs were examined. We recovered 85 variables among a total of 158 known variable stars in these 16 fields. Most of the unrecovered variables are located in the fields observed less frequently. We also detected 58 variable stars which are not listed in the International Variable Star Index of the American Association of Variable Star Observers. These variable stars are classified as 3 RR Lyrae, 4 Cepheid, 1 δ Scuti, 5 Mira, 15 semi-regular, and 27 eclipsing binaries based on the periodicity and the profile of the light curves.

  11. Heart rate variability in healthy population

    International Nuclear Information System (INIS)

    Alamgir, M.; Hussain, M.M.

    2010-01-01

    Background: Heart rate variability has been considered as an indicator of autonomic status. Little work has been done on heart rate variability in normal healthy volunteers. We aimed at evolving the reference values of heart rate variability in our healthy population. Methods: Twenty-four hour holter monitoring of 37 healthy individuals was done using Holter ECG recorder 'Life card CF' from 'Reynolds Medical'. Heart rate variability in both time and frequency domains was analysed with 'Reynolds Medical Pathfinder Digital/700'. Results: The heart rate variability in normal healthy volunteers of our population was found in time domain using standard deviation of R-R intervals (SDNN), standard deviation of average NN intervals (SDANN), and Square root of the mean squared differences of successive NN intervals (RMSSD). Variation in heart rate variability indices was observed between local and foreign volunteers and RMSSD was found significantly increased (p<0.05) in local population. Conclusions: The values of heart rate variability (RMSSD) in healthy Pakistani volunteers were found increased compared to the foreign data reflecting parasympathetic dominance in our population. (author)

  12. The temporal variability of species densities

    International Nuclear Information System (INIS)

    Redfearn, A.; Pimm, S.L.

    1993-01-01

    Ecologists use the term 'stability' to mean to number of different things (Pimm 1984a). One use is to equate stability with low variability in population density over time (henceforth, temporal variability). Temporal variability varies greatly from species to species, so what effects it? There are at least three sets of factors: the variability of extrinsic abiotic factors, food web structure, and the intrinsic features of the species themselves. We can measure temporal variability using at least three statistics: the coefficient of variation of density (CV); the standard deviation of the logarithms of density (SDL); and the variance in the differences between logarithms of density for pairs of consecutive years (called annual variability, hence AV, b y Wolda 1978). There are advantages and disadvantages to each measure (Williamson 1984), though in our experience, the measures are strongly correlated across sets of taxonomically related species. The increasing availability of long-term data sets allows one to calculate these statistics for many species and so to begin to understand the various causes of species differences in temporal variability

  13. Examining Impulse-Variability in Kicking.

    Science.gov (United States)

    Chappell, Andrew; Molina, Sergio L; McKibben, Jonathon; Stodden, David F

    2016-07-01

    This study examined variability in kicking speed and spatial accuracy to test the impulse-variability theory prediction of an inverted-U function and the speed-accuracy trade-off. Twenty-eight 18- to 25-year-old adults kicked a playground ball at various percentages (50-100%) of their maximum speed at a wall target. Speed variability and spatial error were analyzed using repeated-measures ANOVA with built-in polynomial contrasts. Results indicated a significant inverse linear trajectory for speed variability (p < .001, η2= .345) where 50% and 60% maximum speed had significantly higher variability than the 100% condition. A significant quadratic fit was found for spatial error scores of mean radial error (p < .0001, η2 = .474) and subject-centroid radial error (p < .0001, η2 = .453). Findings suggest variability and accuracy of multijoint, ballistic skill performance may not follow the general principles of impulse-variability theory or the speed-accuracy trade-off.

  14. Contextuality is about identity of random variables

    International Nuclear Information System (INIS)

    Dzhafarov, Ehtibar N; Kujala, Janne V

    2014-01-01

    Contextual situations are those in which seemingly ‘the same’ random variable changes its identity depending on the conditions under which it is recorded. Such a change of identity is observed whenever the assumption that the variable is one and the same under different conditions leads to contradictions when one considers its joint distribution with other random variables (this is the essence of all Bell-type theorems). In our Contextuality-by-Default approach, instead of asking why or how the conditions force ‘one and the same’ random variable to change ‘its’ identity, any two random variables recorded under different conditions are considered different ‘automatically.’ They are never the same, nor are they jointly distributed, but one can always impose on them a joint distribution (probabilistic coupling). The special situations when there is a coupling in which these random variables are equal with probability 1 are considered noncontextual. Contextuality means that such couplings do not exist. We argue that the determination of the identity of random variables by conditions under which they are recorded is not a causal relationship and cannot violate laws of physics. (paper)

  15. A variable stiffness joint with electrospun P(VDF-TrFE-CTFE) variable stiffness springs

    NARCIS (Netherlands)

    Carloni, Raffaella; Lapp, Valerie I.; Cremonese, Andrea; Belcari, Juri; Zucchelli, Andrea

    This letter presents a novel rotational variable stiffness joint that relies on one motor and a set of variable stiffness springs. The variable stiffness springs are leaf springs with a layered design, i.e., an electro-active layer of electrospun aligned nanofibers of poly(vinylidene

  16. Validity of a Residualized Dependent Variable after Pretest Covariance Adjustments: Still the Same Variable?

    Science.gov (United States)

    Nimon, Kim; Henson, Robin K.

    2015-01-01

    The authors empirically examined whether the validity of a residualized dependent variable after covariance adjustment is comparable to that of the original variable of interest. When variance of a dependent variable is removed as a result of one or more covariates, the residual variance may not reflect the same meaning. Using the pretest-posttest…

  17. How to get rid of W: a latent variables approach to modelling spatially lagged variables

    NARCIS (Netherlands)

    Folmer, H.; Oud, J.

    2008-01-01

    In this paper we propose a structural equation model (SEM) with latent variables to model spatial dependence. Rather than using the spatial weights matrix W, we propose to use latent variables to represent spatial dependence and spillover effects, of which the observed spatially lagged variables are

  18. How to get rid of W : a latent variables approach to modelling spatially lagged variables

    NARCIS (Netherlands)

    Folmer, Henk; Oud, Johan

    2008-01-01

    In this paper we propose a structural equation model (SEM) with latent variables to model spatial dependence. Rather than using the spatial weights matrix W, we propose to use latent variables to represent spatial dependence and spillover effects, of which the observed spatially lagged variables are

  19. Gait variability: methods, modeling and meaning

    Directory of Open Access Journals (Sweden)

    Hausdorff Jeffrey M

    2005-07-01

    Full Text Available Abstract The study of gait variability, the stride-to-stride fluctuations in walking, offers a complementary way of quantifying locomotion and its changes with aging and disease as well as a means of monitoring the effects of therapeutic interventions and rehabilitation. Previous work has suggested that measures of gait variability may be more closely related to falls, a serious consequence of many gait disorders, than are measures based on the mean values of other walking parameters. The Current JNER series presents nine reports on the results of recent investigations into gait variability. One novel method for collecting unconstrained, ambulatory data is reviewed, and a primer on analysis methods is presented along with a heuristic approach to summarizing variability measures. In addition, the first studies of gait variability in animal models of neurodegenerative disease are described, as is a mathematical model of human walking that characterizes certain complex (multifractal features of the motor control's pattern generator. Another investigation demonstrates that, whereas both healthy older controls and patients with a higher-level gait disorder walk more slowly in reduced lighting, only the latter's stride variability increases. Studies of the effects of dual tasks suggest that the regulation of the stride-to-stride fluctuations in stride width and stride time may be influenced by attention loading and may require cognitive input. Finally, a report of gait variability in over 500 subjects, probably the largest study of this kind, suggests how step width variability may relate to fall risk. Together, these studies provide new insights into the factors that regulate the stride-to-stride fluctuations in walking and pave the way for expanded research into the control of gait and the practical application of measures of gait variability in the clinical setting.

  20. Variable displacement alpha-type Stirling engine

    Science.gov (United States)

    Homutescu, V. M.; Bălănescu, D. T.; Panaite, C. E.; Atanasiu, M. V.

    2016-08-01

    The basic design and construction of an alpha-type Stirling engine with on load variable displacement is presented. The variable displacement is obtained through a planar quadrilateral linkage with one on load movable ground link. The physico-mathematical model used for analyzing the variable displacement alpha-type Stirling engine behavior is an isothermal model that takes into account the real movement of the pistons. Performances and power adjustment capabilities of such alpha-type Stirling engine are calculated and analyzed. An exemplification through the use of the numerical simulation was performed in this regard.

  1. Pulsation properties of Mira long period variables

    International Nuclear Information System (INIS)

    Cahn, J.H.

    1980-01-01

    A matter of great interest to variable star students concerns the mode of pulsation of Mira long period variables. In this report we first give observational evidence for the pulsation constant Q. We then compare the observations with calculations. Next, we review two interesting groups of papers dealing with hydrodynamic properties of long period variables. In the first, a fully dynamic nonlinear calculation maps out the Mira instability domain. In the second, special attention is paid to shock propagation beyond the photosphere which in large measure accounts for the complex spectra from this region. (orig./WL)

  2. The EPICS process variable Gateway Version 2

    International Nuclear Information System (INIS)

    Evans, K.

    2005-01-01

    The EPICS Process Variable Gateway is both a Channel Access Server and Channel Access Client that provides a means for many clients, typically on different subnets, to access a process variable while making only one connection to the server that owns the process variable. It also provides additional access security beyond that implemented on the server. It thus protects critical servers while providing suitably restricted access to needed process variables. The original version of the Gateway worked with EPICS Base 3.13 but required a special version, since the changes necessary for its operation were never incorporated into EPICS Base. Version 2 works with any standard EPICS Base 3.14.6 or later and has many improvements in both performance and features over the older version. The Gateway is now used at many institutions and has become a stable, high-performance application. It is capable of handling tens of thousands of process variables with hundreds of thousands of events per second. It has run for over three months in a production environment without having to be restarted. It has many internal process variables that can be used to monitor its state using standard EPICS client tools, such as MEDM and StripTool. Other internal process variables can be used to stop the Gateway, make several kinds of reports, or change the access security without stopping the Gateway. It can even be started on remote workstations from MEDM by using a Secure Shell script. This paper will describe the new Gateway and how it is used. The Gateway is both a server (like an EPICS Input/Output Controller (IOC)) and a client (like the EPICS Motif Editor and Display Manager (MEDM), StripTool, and others). Clients connect to the server side, and the client side connects to IOCs and other servers, possibly other Gateways. See Fig. 1. There are perhaps three principal reasons for using the Gateway: (1) it allows many clients to access a process variable while making only one connection to

  3. A survey of hidden-variables theories

    CERN Document Server

    Belinfante, F J

    1973-01-01

    A Survey of Hidden-Variables Theories is a three-part book on the hidden-variable theories, referred in this book as """"theories of the first kind"""". Part I reviews the motives in developing different types of hidden-variables theories. The quest for determinism led to theories of the first kind; the quest for theories that look like causal theories when applied to spatially separated systems that interacted in the past led to theories of the second kind. Parts II and III further describe the theories of the first kind and second kind, respectively. This book is written to make the literat

  4. hmF2 variability over Havana

    International Nuclear Information System (INIS)

    Lazo, B.; Alazo, K.; Rodriguez, M.; Calzadilla, A.

    2003-01-01

    The hmF2 variability over Havana station (Geo. Latitude 23 deg. N, Geo Longitude 278 deg. E; Dip 54.6 deg. N; Modip: 44.8 deg. N) is presented. In this study different solar and seasonal conditions are considered. The results show that, in general, standard deviation of hmF2 is quite irregular and reaches its values at nighttimes hours. Lower and upper quartiles variability has a similar behaviour to IQ variability, showing its higher values at nighttimes too. (author)

  5. A Core Language for Separate Variability Modeling

    DEFF Research Database (Denmark)

    Iosif-Lazăr, Alexandru Florin; Wasowski, Andrzej; Schaefer, Ina

    2014-01-01

    Separate variability modeling adds variability to a modeling language without requiring modifications of the language or the supporting tools. We define a core language for separate variability modeling using a single kind of variation point to define transformations of software artifacts in object...... hierarchical dependencies between variation points via copying and flattening. Thus, we reduce a model with intricate dependencies to a flat executable model transformation consisting of simple unconditional local variation points. The core semantics is extremely concise: it boils down to two operational rules...

  6. Analytic functions of several complex variables

    CERN Document Server

    Gunning, Robert C

    2009-01-01

    The theory of analytic functions of several complex variables enjoyed a period of remarkable development in the middle part of the twentieth century. After initial successes by Poincaré and others in the late 19th and early 20th centuries, the theory encountered obstacles that prevented it from growing quickly into an analogue of the theory for functions of one complex variable. Beginning in the 1930s, initially through the work of Oka, then H. Cartan, and continuing with the work of Grauert, Remmert, and others, new tools were introduced into the theory of several complex variables that resol

  7. Construction of Database for Pulsating Variable Stars

    Science.gov (United States)

    Chen, B. Q.; Yang, M.; Jiang, B. W.

    2011-07-01

    A database for the pulsating variable stars is constructed for Chinese astronomers to study the variable stars conveniently. The database includes about 230000 variable stars in the Galactic bulge, LMC and SMC observed by the MACHO (MAssive Compact Halo Objects) and OGLE (Optical Gravitational Lensing Experiment) projects at present. The software used for the construction is LAMP, i.e., Linux+Apache+MySQL+PHP. A web page is provided to search the photometric data and the light curve in the database through the right ascension and declination of the object. More data will be incorporated into the database.

  8. 42 Variability Bugs in the Linux Kernel

    DEFF Research Database (Denmark)

    Abal, Iago; Brabrand, Claus; Wasowski, Andrzej

    2014-01-01

    Feature-sensitive verification pursues effective analysis of the exponentially many variants of a program family. However, researchers lack examples of concrete bugs induced by variability, occurring in real large-scale systems. Such a collection of bugs is a requirement for goal-oriented research...... provide self-contained simplified C99 versions of the bugs, facilitating understanding and tool evaluation. Our study provides insights into the nature and occurrence of variability bugs in a large C software system, and shows in what ways variability affects and increases the complexity of software bugs....

  9. Variable selection by lasso-type methods

    Directory of Open Access Journals (Sweden)

    Sohail Chand

    2011-09-01

    Full Text Available Variable selection is an important property of shrinkage methods. The adaptive lasso is an oracle procedure and can do consistent variable selection. In this paper, we provide an explanation that how use of adaptive weights make it possible for the adaptive lasso to satisfy the necessary and almost sufcient condition for consistent variable selection. We suggest a novel algorithm and give an important result that for the adaptive lasso if predictors are normalised after the introduction of adaptive weights, it makes the adaptive lasso performance identical to the lasso.

  10. A classification of hidden-variable properties

    International Nuclear Information System (INIS)

    Brandenburger, Adam; Yanofsky, Noson

    2008-01-01

    Hidden variables are extra components added to try to banish counterintuitive features of quantum mechanics. We start with a quantum-mechanical model and describe various properties that can be asked of a hidden-variable model. We present six such properties and a Venn diagram of how they are related. With two existence theorems and three no-go theorems (EPR, Bell and Kochen-Specker), we show which properties of empirically equivalent hidden-variable models are possible and which are not. Formally, our treatment relies only on classical probability models, and physical phenomena are used only to motivate which models to choose

  11. Using variable combination population analysis for variable selection in multivariate calibration.

    Science.gov (United States)

    Yun, Yong-Huan; Wang, Wei-Ting; Deng, Bai-Chuan; Lai, Guang-Bi; Liu, Xin-bo; Ren, Da-Bing; Liang, Yi-Zeng; Fan, Wei; Xu, Qing-Song

    2015-03-03

    Variable (wavelength or feature) selection techniques have become a critical step for the analysis of datasets with high number of variables and relatively few samples. In this study, a novel variable selection strategy, variable combination population analysis (VCPA), was proposed. This strategy consists of two crucial procedures. First, the exponentially decreasing function (EDF), which is the simple and effective principle of 'survival of the fittest' from Darwin's natural evolution theory, is employed to determine the number of variables to keep and continuously shrink the variable space. Second, in each EDF run, binary matrix sampling (BMS) strategy that gives each variable the same chance to be selected and generates different variable combinations, is used to produce a population of subsets to construct a population of sub-models. Then, model population analysis (MPA) is employed to find the variable subsets with the lower root mean squares error of cross validation (RMSECV). The frequency of each variable appearing in the best 10% sub-models is computed. The higher the frequency is, the more important the variable is. The performance of the proposed procedure was investigated using three real NIR datasets. The results indicate that VCPA is a good variable selection strategy when compared with four high performing variable selection methods: genetic algorithm-partial least squares (GA-PLS), Monte Carlo uninformative variable elimination by PLS (MC-UVE-PLS), competitive adaptive reweighted sampling (CARS) and iteratively retains informative variables (IRIV). The MATLAB source code of VCPA is available for academic research on the website: http://www.mathworks.com/matlabcentral/fileexchange/authors/498750. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. What do we know about variability?

    Directory of Open Access Journals (Sweden)

    Sergey G Inge-Vechtomov

    2010-12-01

    Full Text Available Contemporary phenomenological classification of variability types meets lots of contradictions. There is a single group of “mutations”: gene, chromosomal, genomic ones, which originate through different mechanisms. Ontogenetic variability puts even more questions because it embraces: modifications (regulation of gene expression, genetic variations (mutations and recombination and epigenetic variations (and inheritance in addition, with no clear criterions of the latter ones definition so far. Modifications and heritable variations are appeared to be closer to each other then we suspected before. An alternative classification of variability may be proposed basing upon template principle in biology. There is no direct correspondence between mechanisms and phenomenology of variation. It is a witness of a newparadigm coming in biological variability understanding.

  13. Can time be a discrete dynamical variable

    International Nuclear Information System (INIS)

    Lee, T.D.

    1983-01-01

    The possibility that time can be regarded as a discrete dynamical variable is examined through all phases of mechanics: from classical mechanics to nonrelativistic quantum mechanics, and to relativistic quantum field theories. (orig.)

  14. On the concept of a linguistic variable

    International Nuclear Information System (INIS)

    Kerre, E.

    1996-01-01

    The concept of a linguistic variable plays a crucial role in the representation of imprecise knowledge in information sciences. A variable is called linguistic as soon as its values are linguistic terms rather than numerical ones. The power of daily communication and common sense reasoning lies in the use of such linguistic values. Even when exact numerical values are available, experts tend to transform these values into linguistic ones. A physician will usually translate a numerical measurement of a blood pressure into linguistic specifications such as normal, very high, too low... Zadeh has argued that the set of values for a linguistic variable assumes a more-or-less fixed structure. Starting from an atomic value and its antonym all remaining values are constructed using logical connectives on the one hand and linguistic hedges on the other hand. In this paper we will describe how to represent the value set of a linguistic variable in general and of linguistic hedges in particular

  15. Signal Enhancement with Variable Span Linear Filters

    DEFF Research Database (Denmark)

    Benesty, Jacob; Christensen, Mads Græsbøll; Jensen, Jesper Rindom

    This book introduces readers to the novel concept of variable span speech enhancement filters, and demonstrates how it can be used for effective noise reduction in various ways. Further, the book provides the accompanying Matlab code, allowing readers to easily implement the main ideas discussed....... Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal......-to-noise ratio, Wiener, and tradeoff filters (including their new generalizations) can be obtained using the variable span filter framework. It then illustrates how the variable span filters can be applied in various contexts, namely in single-channel STFT-based enhancement, in multichannel enhancement in both...

  16. Rural variable speed limits : phase II.

    Science.gov (United States)

    2012-05-01

    The Wyoming Department of Transportation (WYDOT) installed its first variable speed limit (VSL) corridor along : Interstate 80 in the Elk Mountain Corridor in the Spring of 2009 in an effort to improve safety and reduce road closures, : particularly ...

  17. Statistical identification of effective input variables

    International Nuclear Information System (INIS)

    Vaurio, J.K.

    1982-09-01

    A statistical sensitivity analysis procedure has been developed for ranking the input data of large computer codes in the order of sensitivity-importance. The method is economical for large codes with many input variables, since it uses a relatively small number of computer runs. No prior judgemental elimination of input variables is needed. The sceening method is based on stagewise correlation and extensive regression analysis of output values calculated with selected input value combinations. The regression process deals with multivariate nonlinear functions, and statistical tests are also available for identifying input variables that contribute to threshold effects, i.e., discontinuities in the output variables. A computer code SCREEN has been developed for implementing the screening techniques. The efficiency has been demonstrated by several examples and applied to a fast reactor safety analysis code (Venus-II). However, the methods and the coding are general and not limited to such applications

  18. Fractal Structures For Mems Variable Capacitors

    KAUST Repository

    Elshurafa, Amro M.; Radwan, Ahmed Gomaa Ahmed; Emira, Ahmed A.; Salama, Khaled N.

    2014-01-01

    In accordance with the present disclosure, one embodiment of a fractal variable capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure, wherein the capacitor body has an upper first metal plate with a fractal shape

  19. DATA COLLECTION METHOD FOR PEDESTRIAN MOVEMENT VARIABLES

    Directory of Open Access Journals (Sweden)

    Hajime Inamura

    2000-01-01

    Full Text Available The need of tools for design and evaluation of pedestrian areas, subways stations, entrance hall, shopping mall, escape routes, stadium etc lead to the necessity of a pedestrian model. One approach pedestrian model is Microscopic Pedestrian Simulation Model. To be able to develop and calibrate a microscopic pedestrian simulation model, a number of variables need to be considered. As the first step of model development, some data was collected using video and the coordinate of the head path through image processing were also taken. Several numbers of variables can be gathered to describe the behavior of pedestrian from a different point of view. This paper describes how to obtain variables from video taking and simple image processing that can represent the movement of pedestrians and its variables

  20. A canonical neural mechanism for behavioral variability

    Science.gov (United States)

    Darshan, Ran; Wood, William E.; Peters, Susan; Leblois, Arthur; Hansel, David

    2017-05-01

    The ability to generate variable movements is essential for learning and adjusting complex behaviours. This variability has been linked to the temporal irregularity of neuronal activity in the central nervous system. However, how neuronal irregularity actually translates into behavioural variability is unclear. Here we combine modelling, electrophysiological and behavioural studies to address this issue. We demonstrate that a model circuit comprising topographically organized and strongly recurrent neural networks can autonomously generate irregular motor behaviours. Simultaneous recordings of neurons in singing finches reveal that neural correlations increase across the circuit driving song variability, in agreement with the model predictions. Analysing behavioural data, we find remarkable similarities in the babbling statistics of 5-6-month-old human infants and juveniles from three songbird species and show that our model naturally accounts for these `universal' statistics.

  1. Zooplankton variability in the Zuari estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, V.R.; Achuthankutty, C.T.; Nair, S.R.S.

    Short term variability in the secondary production and composition of zooplankton were studied during February to March 1979 by collecting zooplankton every alternate day from a station located near the mouth of Zuari. Irregularity in the production...

  2. Percutaneous nephrolithotomy; alarming variables for postoperative bleeding

    Directory of Open Access Journals (Sweden)

    Shakhawan H.A. Said

    2017-03-01

    Conclusion: According to our present results stone complexity (GSS grade 3 and 4, history of ipsilateral renal stone surgery, and occurrence of intraoperative pelvicalyceal perforation are alarming variables for post-PCNL bleeding.

  3. Signal enhancement with variable span linear filters

    CERN Document Server

    Benesty, Jacob; Jensen, Jesper R

    2016-01-01

    This book introduces readers to the novel concept of variable span speech enhancement filters, and demonstrates how it can be used for effective noise reduction in various ways. Further, the book provides the accompanying Matlab code, allowing readers to easily implement the main ideas discussed. Variable span filters combine the ideas of optimal linear filters with those of subspace methods, as they involve the joint diagonalization of the correlation matrices of the desired signal and the noise. The book shows how some well-known filter designs, e.g. the minimum distortion, maximum signal-to-noise ratio, Wiener, and tradeoff filters (including their new generalizations) can be obtained using the variable span filter framework. It then illustrates how the variable span filters can be applied in various contexts, namely in single-channel STFT-based enhancement, in multichannel enhancement in both the time and STFT domains, and, lastly, in time-domain binaural enhancement. In these contexts, the properties of ...

  4. Realization of an integral using anticommuting variables

    International Nuclear Information System (INIS)

    Valuev, B.N.

    1979-01-01

    It is shown that the integral defined by Berezin over anticommuting variables may be realized as a trace on the Clifford algebra. In fact, this realization makes precise the definition of the integral

  5. Instrumental Variables in the Long Run

    DEFF Research Database (Denmark)

    Casey, Gregory; Klemp, Marc Patrick Brag

    2017-01-01

    In the study of long-run economic growth, it is common to use historical or geographical variables as instruments for contemporary endogenous regressors. We study the interpretation of these conventional instrumental variable (IV) regressions in a general, yet simple, framework. Our aim...... quantitative implications for the field of long-run economic growth. We also use our framework to examine related empirical techniques. We find that two prominent regression methodologies - using gravity-based instruments for trade and including ancestry-adjusted variables in linear regression models - have...... is to estimate the long-run causal effect of changes in the endogenous explanatory variable. We find that conventional IV regressions generally cannot recover this parameter of interest. To estimate this parameter, therefore, we develop an augmented IV estimator that combines the conventional regression...

  6. Compact variable rate laser for space application

    Data.gov (United States)

    National Aeronautics and Space Administration — We will focus on the development and test of high reliable, radiation tolerant, compact laser for planetary mission.  The laser will be able to operate at variable...

  7. Robustness studies on coal gasification process variables

    African Journals Online (AJOL)

    coal before feeding to the gasification process [1]. .... to-control variables will make up the terms in the response surface model for the ... Montgomery (1999) explained that all the Taguchi engineering objectives for a robust ..... software [3].

  8. Measure of uncertainty in regional grade variability

    NARCIS (Netherlands)

    Tutmez, B.; Kaymak, U.; Melin, P.; Castillo, O.; Gomez Ramirez, E.; Kacprzyk, J.; Pedrycz, W.

    2007-01-01

    Because the geological events are neither homogeneous nor isotropic, the geological investigations are characterized by particularly high uncertainties. This paper presents a hybrid methodology for measuring of uncertainty in regional grade variability. In order to evaluate the fuzziness in grade

  9. Temporal relationship between climate variability, Prosopis juliflora ...

    African Journals Online (AJOL)

    Kyuma

    Key words: Climate, drylands, livestock, Prosopis juliflora, variability vegetation, trends, mesquite. ... climate change is costly and predictions are that both it and its cost will escalate ... Resilience Alliance, 2010; Tennigkeit and Wilkes, 2008;.

  10. Variable Delay in port-Hamiltonian Telemanipulation

    NARCIS (Netherlands)

    Secchi, C; Stramigioli, Stefano; Fantuzzi, C.

    2006-01-01

    In several applications involving bilateral telemanipulation, master and slave act at different power scales. In this paper a strategy for passively dealing with variable communication delay in scaled port-Hamiltonian based telemanipulation over packet switched networks is proposed.

  11. SELECTING QUASARS BY THEIR INTRINSIC VARIABILITY

    International Nuclear Information System (INIS)

    Schmidt, Kasper B.; Rix, Hans-Walter; Jester, Sebastian; Hennawi, Joseph F.; Marshall, Philip J.; Dobler, Gregory

    2010-01-01

    We present a new and simple technique for selecting extensive, complete, and pure quasar samples, based on their intrinsic variability. We parameterize the single-band variability by a power-law model for the light-curve structure function, with amplitude A and power-law index γ. We show that quasars can be efficiently separated from other non-variable and variable sources by the location of the individual sources in the A-γ plane. We use ∼60 epochs of imaging data, taken over ∼5 years, from the SDSS stripe 82 (S82) survey, where extensive spectroscopy provides a reference sample of quasars, to demonstrate the power of variability as a quasar classifier in multi-epoch surveys. For UV-excess selected objects, variability performs just as well as the standard SDSS color selection, identifying quasars with a completeness of 90% and a purity of 95%. In the redshift range 2.5 < z < 3, where color selection is known to be problematic, variability can select quasars with a completeness of 90% and a purity of 96%. This is a factor of 5-10 times more pure than existing color selection of quasars in this redshift range. Selecting objects from a broad griz color box without u-band information, variability selection in S82 can afford completeness and purity of 92%, despite a factor of 30 more contaminants than quasars in the color-selected feeder sample. This confirms that the fraction of quasars hidden in the 'stellar locus' of color space is small. To test variability selection in the context of Pan-STARRS 1 (PS1) we created mock PS1 data by down-sampling the S82 data to just six epochs over 3 years. Even with this much sparser time sampling, variability is an encouragingly efficient classifier. For instance, a 92% pure and 44% complete quasar candidate sample is attainable from the above griz-selected catalog. Finally, we show that the presented A-γ technique, besides selecting clean and pure samples of quasars (which are stochastically varying objects), is also

  12. Investigations of cataclysmic variables by ESA INTEGRAL

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Blažek, Martin

    2012-01-01

    Roč. 83, č. 2 (2012), s. 659-664 ISSN 0037-8720. [Workshop on the golden age of cataclysmic variables and related objects /2./. Palermo , 09.09.2013-14.09.2013] R&D Projects: GA ČR GA205/08/1207 Institutional research plan: CEZ:AV0Z10030501 Keywords : stars * high-energy sources * cataclysmic variables Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  13. Variable Cycle Intake for Reverse Core Engine

    Science.gov (United States)

    Suciu, Gabriel L (Inventor); Chandler, Jesse M (Inventor); Staubach, Joseph B (Inventor)

    2016-01-01

    A gas generator for a reverse core engine propulsion system has a variable cycle intake for the gas generator, which variable cycle intake includes a duct system. The duct system is configured for being selectively disposed in a first position and a second position, wherein free stream air is fed to the gas generator when in the first position, and fan stream air is fed to the gas generator when in the second position.

  14. New variables for classical and quantum gravity

    Science.gov (United States)

    Ashtekar, Abhay

    1986-01-01

    A Hamiltonian formulation of general relativity based on certain spinorial variables is introduced. These variables simplify the constraints of general relativity considerably and enable one to imbed the constraint surface in the phase space of Einstein's theory into that of Yang-Mills theory. The imbedding suggests new ways of attacking a number of problems in both classical and quantum gravity. Some illustrative applications are discussed.

  15. Machine learning techniques to select variable stars

    Directory of Open Access Journals (Sweden)

    García-Varela Alejandro

    2017-01-01

    Full Text Available In order to perform a supervised classification of variable stars, we propose and evaluate a set of six features extracted from the magnitude density of the light curves. They are used to train automatic classification systems using state-of-the-art classifiers implemented in the R statistical computing environment. We find that random forests is the most successful method to select variables.

  16. Erosion and variability in brand loyalty

    OpenAIRE

    Dekimpe, Marnik; Mellens, M; Steenkamp, J; Vanden Abeele, Pierre

    1996-01-01

    In this paper, we examine the over-time behavior of brand loyalty for a large set of brands drawn from many product categories. Using the brand-loyalty operationalization of Colombo and Morrison (1989), the following conclusions are obtained. First, little support is found for the often-heard contention that brand loyalty is gradually declining over time. Second, while the short-run variability around a brand's mean loyalty level is not negligible, no evidence is found that this variability...

  17. Real variables with basic metric space topology

    CERN Document Server

    Ash, Robert B

    2009-01-01

    Designed for a first course in real variables, this text presents the fundamentals for more advanced mathematical work, particularly in the areas of complex variables, measure theory, differential equations, functional analysis, and probability. Geared toward advanced undergraduate and graduate students of mathematics, it is also appropriate for students of engineering, physics, and economics who seek an understanding of real analysis.The author encourages an intuitive approach to problem solving and offers concrete examples, diagrams, and geometric or physical interpretations of results. Deta

  18. Conspicuous plumage colours are highly variable

    OpenAIRE

    Delhey, Kaspar; Szecsenyi, Beatrice; Nakagawa, Shinichi; Peters, Anne

    2017-01-01

    Elaborate ornamental traits are often under directional selection for greater elaboration, which in theory should deplete underlying genetic variation. Despite this, many ornamental traits appear to remain highly variable and how this essential variation is maintained is a key question in evolutionary biology. One way to address this question is to compare differences in intraspecific variability across different types of traits to determine whether high levels of variation are associated wit...

  19. Galactic models with variable spiral structure

    International Nuclear Information System (INIS)

    James, R.A.; Sellwood, J.A.

    1978-01-01

    A series of three-dimensional computer simulations of disc galaxies has been run in which the self-consistent potential of the disc stars is supplemented by that arising from a small uniform Population II sphere. The models show variable spiral structure, which is more pronounced for thin discs. In addition, the thin discs form weak bars. In one case variable spiral structure associated with this bar has been seen. The relaxed discs are cool outside resonance regions. (author)

  20. Handbook of latent variable and related models

    CERN Document Server

    Lee, Sik-Yum

    2011-01-01

    This Handbook covers latent variable models, which are a flexible class of models for modeling multivariate data to explore relationships among observed and latent variables.- Covers a wide class of important models- Models and statistical methods described provide tools for analyzing a wide spectrum of complicated data- Includes illustrative examples with real data sets from business, education, medicine, public health and sociology.- Demonstrates the use of a wide variety of statistical, computational, and mathematical techniques.

  1. Obtención de concretos autocompactantes empleando residuos de demolición

    OpenAIRE

    Silva, Yimmy; Robayo, Rafael; Mattey, Pedro; Delvasto, Silvio

    2015-01-01

    Uno de los principales problemas ambientales es la disposición o reciclaje de los materiales de desechos de construcción y/o demolición y el gran volumen de estos, que en una ciudad como Bogotá es del orden de 15 millones de metros cúbicos por año. Uno de los materiales más comunes en estos escombros son los residuos de ladrillos de arcilla unidos con mortero de cemento (residuo de mampostería-RM), que son una fracción importante del volumen total de desechos. Por tal motivo, el objetivo de e...

  2. ESTUDIO CONFORMACIONAL EN ALGUNAS 1,3-OXAZINAS Y 1,3-BENZOXAZINAS EMPLEANDO METODOS TEORICOS.

    OpenAIRE

    HURTADO OCAMPO, SANDRA MARCELA; HURTADO OCAMPO, SANDRA MARCELA

    2007-01-01

    En la década del cincuenta, resultados experimentales entregados por Urbanski y colaboradores [1] pusieron en evidencia propiedades antituberculósicas y antitumorales en compuestos del tipo 5-nitro-R-N-1 ,3- oxazínicos. Como resultado de un proceso relati 187p.

  3. ESTUDIO DE LA MADURACIÓN DE CARNE DE CORDERO EMPLEANDO ELECTROFORESIS SDS-PAGE

    Directory of Open Access Journals (Sweden)

    Gina Torres

    2012-10-01

    Full Text Available La maduración de la carne es causadapor reacciones metabólicas que producencambios en su calidad, mejorando las característicasorganolépticas como la terneza,la jugosidad y el color. El presenteestudio tuvo como objetivo encontrarlos cambios producidos en las proteínassarcoplasmáticas y miofibrilares durantela instauración del rigor mortis y lamaduración en carne de cordero semiestabulado(AS y cordero alimentado porpastoreo (AP. Para tal fin se tomaronmuestras del músculo Longissimus dorside corderos de raza Dorper x criollo ¾de diez semanas de edad. Las proteínassarcoplasmáticas se extrajeron con aguay solución salina diluida, y las proteínasmiofibrilares con solución salina concentrada.La cuantificación se hizo por elmétodo de Bradford y la separación porelectroforesis SDS-PAGE.En las proteínas sarcoplasmáticas seobservó la aparición de una banda de146 kDa a los cinco y trece días paralos corderos AS y AP, respectivamente.En las proteínas miofibrilares se encontróevidencia del rigor mortis a las 16h y una intensificación drástica de unabanda de 28 kDa a las 16 h en el corderoAS. Esta banda también se observóen el cordero AP a las 14 h. En todoel proceso se pudo ver la degradacióngradual de la DESMINA, ACTINA YTROPONINA T.

  4. Deconvolution of Moessbauer spectra using Voigt functions; Deconvolucion de espectros Moessbauer empleando funciones Voigt

    Energy Technology Data Exchange (ETDEWEB)

    Flores Ll, H J

    1990-08-15

    The form of the resonance line in Moessbauer spectroscopy is a form of Lorentzian line, but this form of line it enlarges due to several effects: finite thickness of the absorber, instrumental instability, diffusion of Co{sup 57} in crystals and fluctuations in the environment of the emitting nucleus. To take into account this effects it has been used as form of line in Moessbauer spectroscopy the Voigt function that is the convolution of a Lorentzian and a Gaussian. (Author)

  5. Generación de objetos de aprendizaje empleando un enfoque asistido

    OpenAIRE

    Menéndez Domínguez, Victor Hugo; Castellanos Bolaños, María Enriqueta; Zapata González, Alfredo; Prieto Méndez, Manuel Emilio:

    2011-01-01

    El etiquetado de un Objeto de Aprendizaje generalmente es una actividad extenuante y propensa a errores, lo cual afecta directamente la reutilización e interoperabilidad del recurso. En este trabajo se describe un modelo que genera Objetos de Aprendizaje a partir de recursos digitales existentes. El modelo emplea la similitud entre objetos, así como reglas inferidas del conocimiento existente, para proponer metadatos y de esta manera facilitar la descripción del recurso. El modelo ha sido imp...

  6. El rol del profesor y la actividad demostrativa: una experiencia de aula empleando Geogebra

    OpenAIRE

    Mejía, Cristina; Molina, Óscar

    2013-01-01

    En esta experiencia de aula presento un ciclo didáctico que forma parte del trabajo de grado que estoy desarrollando para optar por el título de maestría en docencia de las Matemáticas. Pretendo exponer una experiencia en la que se analiza el rol del profesor, bajo la teoría de la mediación semiótica y fundamentado en la aproximación metodológica para la enseñanza del grupo Æ•G. Tal ciclo planteado en un aula de octavo grado, favorece la construcción de un sistema teórico local y se emplea un...

  7. Síntesis de heterociclos mediante reacciones multicomponente, empleando heteropolicompuestos como catalizadores

    OpenAIRE

    Sánchez, Laura Mabel

    2014-01-01

    La química fina tradicionalmente ha empleado “tecnologías estequiométricas”, las cuales involucran la generación de cantidades enormes de residuos inorgánicos. Dada la necesidad de minimizar el uso de tecnologías contaminantes, hoy en día se hace uso de una serie de estrategias que intentan reducir el impacto ambiental. Una de las propuestas incluye la utilización de las llamadas “reacciones multicomponente” (MCRs), las cuales son reacciones convergentes en las que tres o más materiales de pa...

  8. Cocción de alimentos en Bogotá empleando una cocina solar tipo caja

    Directory of Open Access Journals (Sweden)

    Silvio Alejandro Jiménez Castellanos

    2015-10-01

    Full Text Available Este artículo tiene como objetivo presentar el campo transitorio de temperaturas de una cocina solar tipo caja básica (sin aditamentos tales como: doble acristalamiento, reflectores internos, reflectores externos, línea de alivio de vapor, entre otros; diseñada para las condiciones meteorológicas promedio anuales de Bogotá – Colombia, con el fin de determinar sí con este dispositivo es posible cocinar en esta ciudad. La metodología utilizada comprendió tres fases: el desarrollo de un modelo físico – matemático del proceso de calentamiento, con base en balances de energía para cada uno de los componentes: vidrio, tapa de recipiente, recipiente, absorbedor, pared y fluido, la realización de un experimento computacional en el software Autodesk Algor Simulation y la comparación de los resultados. La temperatura final del agua obtenida por el modelo físico - matemático fue de 81.85 ℃ y la máxima obtenida con la simulación térmica fue de 79.60 ℃. De los resultados se puede concluir que en la ciudad de Bogotá D.C no es posible cocinar con un dispositivo de esta clase.

  9. Degradation of sulfur dioxide using plasma technology; Degradacion de dioxido de azufre empleando tecnologia de plasma

    Energy Technology Data Exchange (ETDEWEB)

    Estrada M, N.; Garcia E, R. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico); Pacheco P, M.; Valdivia B, R.; Pacheco S, J., E-mail: nadiaemz@yahoo.com.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2013-07-01

    This paper presents the electro-chemical study performed for sulfur dioxide (SO{sub 2}) treatment using non thermal plasma coupled to a nano structured fluid bed enhancing the toxic gas removal and the adsorption of acids formed during plasma treatment, more of 80% of removal was obtained. Non thermal plasma was ignited by dielectric barrier discharge (Dbd). The research was developed through an analysis of the chemical kinetics of the process and experimental study of degradation; in each experiment the electrical parameters and the influence of carbon nano structures were monitored to establish the optimal conditions of degradation. We compared the theoretical and experimental results to conclude whether the proposed model is correct for degradation. (Author)

  10. Promoción positiva de vegetales en preescolares costarricenses empleando el Kamishibai

    Directory of Open Access Journals (Sweden)

    Alejandro Chacón-Villalobos

    2015-01-01

    Full Text Available Este artículo presenta la evaluación de la promoción positiva de los vegetales chayote (Sechium edule y brócoli (Brassica oleracea L, al emplear la estrategia de animación a la lectura conocida como Kamishibai. Durante el año 2012 en San José, se estudió la actitud infantil hacia los vegetales (positiva, negativa o neutra, y el agrado sensorial que manifestaba esta población antes de la exposición al Kamishibai y posterior a la misma. Se trabajó con 213 infantes preescolares entre los 4 y 6 años de edad. Las evaluaciones de actitud se efectuaron por medio de una entrevista, mientras que el agrado se estudió por medio de un panel sensorial. La exposición al Kamishibai consistió en 10 intervenciones en la forma de sesiones de cuentos, donde se dividieron los infantes en cuatro grupos según género del menor y género del personaje del cuento que promocionó el vegetal. Todas las actividades se llevaron a cabo en un espacio de juego acondicionado para tal efecto en el salón de clases. A partir de los resultados obtenidos, puede argumentarse que el uso del Kamishibai como técnica de animación a la lectura incrementó significativamente la opinión positiva y el agrado inicial hacia los vegetales en los menores (p<0,05, indiferentemente de su género y del género de las figuras que efectuaron la promoción.

  11. Promoción positiva de vegetales en preescolares costarricenses empleando el Kamishibai

    Directory of Open Access Journals (Sweden)

    Alejandro Chacón-Villalobos

    2015-07-01

    Full Text Available Este artículo presenta la evaluación de la promoción positiva de los vegetales chayote (Sechium edule y brócoli (Brassica oleracea L, al emplear la estrategia de animación a la lectura conocida como Kamishibai. Durante el año 2012 en San José, se estudió la actitud infantil hacia los vegetales (positiva, negativa o neutra, y el agrado sensorial que sentía esta población antes de la exposición al Kamishibai y, posterior a la misma; se trabajó conn 213 infantes preescolares entre los 4 y 6 años de edad. Las evaluaciones de actitud se efectuaron por medio de una entrevista, mientras que el agrado se estudió por medio de un panel sensorial. La exposición al Kamishibai consistió en 10 intervenciones en la forma de sesiones de cuentos, donde se dividieron los infantes en cuatro grupos según género del menor y género del personaje del cuento que promocionó el vegetal. Todas las actividades se llevaron a cabo en un espacio de juego acondicionado para tal efecto en el salón de clases. A partir de los resultados obtenidos, puede argumentarse que el uso de la técnica del Kamishibai como técnica de animación a la lectura incrementó significativamente la opinión positiva y el agrado inicial hacia los vegetales en estas personas menores (p<0,05, indiferentemente de su género y del género de las figuras que efectuaron la promoción.

  12. Promoción positiva de vegetales en preescolares costarricenses empleando el Kamishibai

    OpenAIRE

    Chacón-Villalobos, Alejandro; Molina Angulo, Ruth; Ruíz-González, María José

    2015-01-01

    Este artículo presenta la evaluación de la promoción positiva de los vegetales chayóte (Sechium edule) y brócoli (Brassica olerácea L), al emplear la estrategia de animación a la lectura conocida como Kamishibai. Durante el año 2012 en San José, se estudió la actitud infantil hacia los vegetales (positiva, negativa o neutra), y el agrado sensorial que manifestaba esta población antes de la exposición al Kamishibai y posterior a la misma. Se trabajó con 213 infantes preescolares entre los 4 y ...

  13. VaST: A variability search toolkit

    Science.gov (United States)

    Sokolovsky, K. V.; Lebedev, A. A.

    2018-01-01

    Variability Search Toolkit (VaST) is a software package designed to find variable objects in a series of sky images. It can be run from a script or interactively using its graphical interface. VaST relies on source list matching as opposed to image subtraction. SExtractor is used to generate source lists and perform aperture or PSF-fitting photometry (with PSFEx). Variability indices that characterize scatter and smoothness of a lightcurve are computed for all objects. Candidate variables are identified as objects having high variability index values compared to other objects of similar brightness. The two distinguishing features of VaST are its ability to perform accurate aperture photometry of images obtained with non-linear detectors and handle complex image distortions. The software has been successfully applied to images obtained with telescopes ranging from 0.08 to 2.5 m in diameter equipped with a variety of detectors including CCD, CMOS, MIC and photographic plates. About 1800 variable stars have been discovered with VaST. It is used as a transient detection engine in the New Milky Way (NMW) nova patrol. The code is written in C and can be easily compiled on the majority of UNIX-like systems. VaST is free software available at http://scan.sai.msu.ru/vast/.

  14. Contextuality in canonical systems of random variables

    Science.gov (United States)

    Dzhafarov, Ehtibar N.; Cervantes, Víctor H.; Kujala, Janne V.

    2017-10-01

    Random variables representing measurements, broadly understood to include any responses to any inputs, form a system in which each of them is uniquely identified by its content (that which it measures) and its context (the conditions under which it is recorded). Two random variables are jointly distributed if and only if they share a context. In a canonical representation of a system, all random variables are binary, and every content-sharing pair of random variables has a unique maximal coupling (the joint distribution imposed on them so that they coincide with maximal possible probability). The system is contextual if these maximal couplings are incompatible with the joint distributions of the context-sharing random variables. We propose to represent any system of measurements in a canonical form and to consider the system contextual if and only if its canonical representation is contextual. As an illustration, we establish a criterion for contextuality of the canonical system consisting of all dichotomizations of a single pair of content-sharing categorical random variables. This article is part of the themed issue `Second quantum revolution: foundational questions'.

  15. Incorporating hydrologic variability into nutrient spiraling

    Science.gov (United States)

    Doyle, Martin W.

    2005-09-01

    Nutrient spiraling describes the path of a nutrient molecule within a stream ecosystem, combining the biochemical cycling processes with the downstream driving force of stream discharge. To date, nutrient spiraling approaches have been hampered by their inability to deal with fluctuating flows, as most studies have characterized nutrient retention within only a small range of discharges near base flow. Here hydrologic variability is incorporated into nutrient spiraling theory by drawing on the fluvial geomorphic concept of effective discharge. The effective discharge for nutrient retention is proposed to be that discharge which, over long periods of time, is responsible for the greatest portion of nutrient retention. A developed analytical model predicts that the effective discharge for nutrient retention will equal the modal discharge for small streams or those with little discharge variability. As modal discharge increases or discharge variability increases, the effective discharge becomes increasingly less than the modal discharge. In addition to the effective discharge, a new metric is proposed, the functionally equivalent discharge, which is the single discharge that will reproduce the magnitude of nutrient retention generated by the full hydrologic frequency distribution when all discharge takes place at that rate. The functionally equivalent discharge was found to be the same as the modal discharge at low hydrologic variability, but increasingly different from the modal discharge at large hydrologic variability. The functionally equivalent discharge provides a simple quantitative means of incorporating hydrologic variability into long-term nutrient budgets.

  16. Brown Dwarf Variability: What's Varying and Why?

    Science.gov (United States)

    Marley, Mark Scott

    2014-01-01

    Surveys by ground based telescopes, HST, and Spitzer have revealed that brown dwarfs of most spectral classes exhibit variability. The spectral and temporal signatures of the variability are complex and apparently defy simplistic classification which complicates efforts to model the changes. Important questions include understanding if clearings are forming in an otherwise uniform cloud deck or if thermal perturbations, perhaps associated with breaking gravity waves, are responsible. If clouds are responsible how long does it take for the atmospheric thermal profile to relax from a hot cloudy to a cooler cloudless state? If thermal perturbations are responsible then what atmospheric layers are varying? How do the observed variability timescales compare to atmospheric radiative, chemical, and dynamical timescales? I will address such questions by presenting modeling results for time-varying partly cloudy atmospheres and explore the importance of various atmospheric processes over the relevant timescales for brown dwarfs of a range of effective temperatures. Regardless of the origin of the observed variability, the complexity seen in the atmospheres of the field dwarfs hints at the variability that we may encounter in the next few years in directly imaged young Jupiters. Thus understanding the nature of variability in the field dwarfs, including sensitivity to gravity and metallicity, is of particular importance for exoplanet characterization.

  17. Risk variables in evaluation of transport projects

    Science.gov (United States)

    Vařbuchta, Petr; Kovářová, Hana; Hromádka, Vít; Vítková, Eva

    2017-09-01

    Depending on the constantly increasing demands on assessment of investment projects, especially assessment of large-scale projects in transport and important European projects with wide impacts, there is constantly increasing focus on risk management, whether to find mitigations, creating corrective measures or their implementation in assessment, especially in the context of Cost-Benefit analysis. To project assessment is often used implementation of certain risk variables, which can generate negative impacts of project outputs in framework of assess. Especially in case of transportation infrastructure projects is taken much emphasis on the influence of risk variables. However, currently in case of assessment of transportation projects is in Czech Republic used a few risk variables, which occur in the most projects. This leads to certain limitation in framework of impact assessment of risk variables. This papers aims to specify a new risk variables and process of applying them to already executed project assessment. Based on changes generated by new risk variables will be evaluated differences between original and adapted assessment.

  18. Ecosystem functioning is enveloped by hydrometeorological variability.

    Science.gov (United States)

    Pappas, Christoforos; Mahecha, Miguel D; Frank, David C; Babst, Flurin; Koutsoyiannis, Demetris

    2017-09-01

    Terrestrial ecosystem processes, and the associated vegetation carbon dynamics, respond differently to hydrometeorological variability across timescales, and so does our scientific understanding of the underlying mechanisms. Long-term variability of the terrestrial carbon cycle is not yet well constrained and the resulting climate-biosphere feedbacks are highly uncertain. Here we present a comprehensive overview of hydrometeorological and ecosystem variability from hourly to decadal timescales integrating multiple in situ and remote-sensing datasets characterizing extra-tropical forest sites. We find that ecosystem variability at all sites is confined within a hydrometeorological envelope across sites and timescales. Furthermore, ecosystem variability demonstrates long-term persistence, highlighting ecological memory and slow ecosystem recovery rates after disturbances. However, simulation results with state-of-the-art process-based models do not reflect this long-term persistent behaviour in ecosystem functioning. Accordingly, we develop a cross-time-scale stochastic framework that captures hydrometeorological and ecosystem variability. Our analysis offers a perspective for terrestrial ecosystem modelling and paves the way for new model-data integration opportunities in Earth system sciences.

  19. Purposeful selection of variables in logistic regression

    Directory of Open Access Journals (Sweden)

    Williams David Keith

    2008-12-01

    Full Text Available Abstract Background The main problem in many model-building situations is to choose from a large set of covariates those that should be included in the "best" model. A decision to keep a variable in the model might be based on the clinical or statistical significance. There are several variable selection algorithms in existence. Those methods are mechanical and as such carry some limitations. Hosmer and Lemeshow describe a purposeful selection of covariates within which an analyst makes a variable selection decision at each step of the modeling process. Methods In this paper we introduce an algorithm which automates that process. We conduct a simulation study to compare the performance of this algorithm with three well documented variable selection procedures in SAS PROC LOGISTIC: FORWARD, BACKWARD, and STEPWISE. Results We show that the advantage of this approach is when the analyst is interested in risk factor modeling and not just prediction. In addition to significant covariates, this variable selection procedure has the capability of retaining important confounding variables, resulting potentially in a slightly richer model. Application of the macro is further illustrated with the Hosmer and Lemeshow Worchester Heart Attack Study (WHAS data. Conclusion If an analyst is in need of an algorithm that will help guide the retention of significant covariates as well as confounding ones they should consider this macro as an alternative tool.

  20. The variability is in the sex chromosomes.

    Science.gov (United States)

    Reinhold, Klaus; Engqvist, Leif

    2013-12-01

    Sex differences in the mean trait expression are well documented, not only for traits that are directly associated with reproduction. Less is known about how the variability of traits differs between males and females. In species with sex chromosomes and dosage compensation, the heterogametic sex is expected to show larger trait variability ("sex-chromosome hypothesis"), yet this central prediction, based on fundamental genetic principles, has never been evaluated in detail. Here we show that in species with heterogametic males, male variability in body size is significantly larger than in females, whereas the opposite can be shown for species with heterogametic females. These results support the prediction of the sex-chromosome hypothesis that individuals of the heterogametic sex should be more variable. We argue that the pattern demonstrated here for sex-specific body size variability is likely to apply to any trait and needs to be considered when testing predictions about sex-specific variability and sexual selection. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  1. Eutrophication Modeling Using Variable Chlorophyll Approach

    International Nuclear Information System (INIS)

    Abdolabadi, H.; Sarang, A.; Ardestani, M.; Mahjoobi, E.

    2016-01-01

    In this study, eutrophication was investigated in Lake Ontario to identify the interactions among effective drivers. The complexity of such phenomenon was modeled using a system dynamics approach based on a consideration of constant and variable stoichiometric ratios. The system dynamics approach is a powerful tool for developing object-oriented models to simulate complex phenomena that involve feedback effects. Utilizing stoichiometric ratios is a method for converting the concentrations of state variables. During the physical segmentation of the model, Lake Ontario was divided into two layers, i.e., the epilimnion and hypolimnion, and differential equations were developed for each layer. The model structure included 16 state variables related to phytoplankton, herbivorous zooplankton, carnivorous zooplankton, ammonium, nitrate, dissolved phosphorus, and particulate and dissolved carbon in the epilimnion and hypolimnion during a time horizon of one year. The results of several tests to verify the model, close to 1 Nash-Sutcliff coefficient (0.98), the data correlation coefficient (0.98), and lower standard errors (0.96), have indicated well-suited model’s efficiency. The results revealed that there were significant differences in the concentrations of the state variables in constant and variable stoichiometry simulations. Consequently, the consideration of variable stoichiometric ratios in algae and nutrient concentration simulations may be applied in future modeling studies to enhance the accuracy of the results and reduce the likelihood of inefficient control policies.

  2. Optical variability of the Seyfert galaxy nuclei

    International Nuclear Information System (INIS)

    Lyutyj, V.M.

    1979-01-01

    The results of the UBV observations of compact Seyfert galaxies during 1968-78 are given. The full amplitude ΔB approximately 2sup(m) of the variability of the nucleus of 3C 120 is considerably larger than that of any other Seyfert galaxy. The minimum brightness of 3C 120 in 1978, B=16sup(m).25 was observed for the first time during the photometric history of the object since 1900. The time delay Δt < or approximately 70sup(d) of the variability of colour index U-B of the nucleus of 3C 120 relatively to that of B and B-V have been discovered. This time delay is interpreted as the variability of the Balmer continuum. The nucleus of 2 Zw 136 appears to show such a variability also. The location of 3C 120 and 2 Zw 136 on two-colour diagram corresponds to the combined colours of hot (05) and cold (K-M) stars, if the time delay of U-B variability is taken into account. The colour indices of the nucleus of 3C 120 during the minimum of 1978 (B=16sup(m).25) correspond to those of the ring between the 7''-30'' apertures. This indicates to a very small contributions of the variable source during the 1978 minimum

  3. A novel variable selection approach that iteratively optimizes variable space using weighted binary matrix sampling.

    Science.gov (United States)

    Deng, Bai-chuan; Yun, Yong-huan; Liang, Yi-zeng; Yi, Lun-zhao

    2014-10-07

    In this study, a new optimization algorithm called the Variable Iterative Space Shrinkage Approach (VISSA) that is based on the idea of model population analysis (MPA) is proposed for variable selection. Unlike most of the existing optimization methods for variable selection, VISSA statistically evaluates the performance of variable space in each step of optimization. Weighted binary matrix sampling (WBMS) is proposed to generate sub-models that span the variable subspace. Two rules are highlighted during the optimization procedure. First, the variable space shrinks in each step. Second, the new variable space outperforms the previous one. The second rule, which is rarely satisfied in most of the existing methods, is the core of the VISSA strategy. Compared with some promising variable selection methods such as competitive adaptive reweighted sampling (CARS), Monte Carlo uninformative variable elimination (MCUVE) and iteratively retaining informative variables (IRIV), VISSA showed better prediction ability for the calibration of NIR data. In addition, VISSA is user-friendly; only a few insensitive parameters are needed, and the program terminates automatically without any additional conditions. The Matlab codes for implementing VISSA are freely available on the website: https://sourceforge.net/projects/multivariateanalysis/files/VISSA/.

  4. Variability in large-scale wind power generation: Variability in large-scale wind power generation

    Energy Technology Data Exchange (ETDEWEB)

    Kiviluoma, Juha [VTT Technical Research Centre of Finland, Espoo Finland; Holttinen, Hannele [VTT Technical Research Centre of Finland, Espoo Finland; Weir, David [Energy Department, Norwegian Water Resources and Energy Directorate, Oslo Norway; Scharff, Richard [KTH Royal Institute of Technology, Electric Power Systems, Stockholm Sweden; Söder, Lennart [Royal Institute of Technology, Electric Power Systems, Stockholm Sweden; Menemenlis, Nickie [Institut de recherche Hydro-Québec, Montreal Canada; Cutululis, Nicolaos A. [DTU, Wind Energy, Roskilde Denmark; Danti Lopez, Irene [Electricity Research Centre, University College Dublin, Dublin Ireland; Lannoye, Eamonn [Electric Power Research Institute, Palo Alto California USA; Estanqueiro, Ana [LNEG, Laboratorio Nacional de Energia e Geologia, UESEO, Lisbon Spain; Gomez-Lazaro, Emilio [Renewable Energy Research Institute and DIEEAC/EDII-AB, Castilla-La Mancha University, Albacete Spain; Zhang, Qin [State Grid Corporation of China, Beijing China; Bai, Jianhua [State Grid Energy Research Institute Beijing, Beijing China; Wan, Yih-Huei [National Renewable Energy Laboratory, Transmission and Grid Integration Group, Golden Colorado USA; Milligan, Michael [National Renewable Energy Laboratory, Transmission and Grid Integration Group, Golden Colorado USA

    2015-10-25

    The paper demonstrates the characteristics of wind power variability and net load variability in multiple power systems based on real data from multiple years. Demonstrated characteristics include probability distribution for different ramp durations, seasonal and diurnal variability and low net load events. The comparison shows regions with low variability (Sweden, Spain and Germany), medium variability (Portugal, Ireland, Finland and Denmark) and regions with higher variability (Quebec, Bonneville Power Administration and Electric Reliability Council of Texas in North America; Gansu, Jilin and Liaoning in China; and Norway and offshore wind power in Denmark). For regions with low variability, the maximum 1 h wind ramps are below 10% of nominal capacity, and for regions with high variability, they may be close to 30%. Wind power variability is mainly explained by the extent of geographical spread, but also higher capacity factor causes higher variability. It was also shown how wind power ramps are autocorrelated and dependent on the operating output level. When wind power was concentrated in smaller area, there were outliers with high changes in wind output, which were not present in large areas with well-dispersed wind power.

  5. Photometric Variability of the Be Star Population

    Energy Technology Data Exchange (ETDEWEB)

    Labadie-Bartz, Jonathan; Pepper, Joshua; McSwain, M. Virginia [Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA 18015 (United States); Bjorkman, J. E.; Bjorkman, K. S. [Ritter Observatory, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft, Toledo, OH 43606-3390 (United States); Lund, Michael B.; Rodriguez, Joseph E.; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Stevens, Daniel J. [Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); James, David J. [Cerro Tololo Inter-American Observatory, Casilla 603 La Serena (Chile); Kuhn, Rudolf B. [Southern African Large Telescope, P.O. Box 9, Observatory 7935, Cape Town (South Africa); Siverd, Robert J. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Santa Barbara, CA 93117 (United States); Beatty, Thomas G. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

    2017-06-01

    Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.

  6. Photometric Variability of the Be Star Population

    International Nuclear Information System (INIS)

    Labadie-Bartz, Jonathan; Pepper, Joshua; McSwain, M. Virginia; Bjorkman, J. E.; Bjorkman, K. S.; Lund, Michael B.; Rodriguez, Joseph E.; Stassun, Keivan G.; Stevens, Daniel J.; James, David J.; Kuhn, Rudolf B.; Siverd, Robert J.; Beatty, Thomas G.

    2017-01-01

    Be stars have generally been characterized by the emission lines in their spectra, and especially the time variability of those spectroscopic features. They are known to also exhibit photometric variability at multiple timescales, but have not been broadly compared and analyzed by that behavior. We have taken advantage of the advent of wide-field, long-baseline, and high-cadence photometric surveys that search for transiting exoplanets to perform a comprehensive analysis of brightness variations among a large number of known Be stars. The photometric data comes from the KELT transit survey, with a typical cadence of 30 minutes, a baseline of up to 10 years, photometric precision of about 1%, and coverage of about 60% of the sky. We analyze KELT light curves of 610 known Be stars in both the northern and southern hemispheres in an effort to study their variability. Consistent with other studies of Be star variability, we find most of the stars to be photometrically variable. We derive lower limits on the fraction of stars in our sample that exhibit features consistent with non-radial pulsations (25%), outbursts (36%), and long-term trends in the circumstellar disk (37%), and show how these are correlated with spectral sub-types. Other types of variability, such as those owing to binarity, are also explored. Simultaneous spectroscopy for some of these systems from the Be Star Spectra database allow us to better understand the physical causes for the observed variability, especially in cases of outbursts and changes in the disk.

  7. Long-Period Variability in o Ceti

    Science.gov (United States)

    Templeton, Matthew R.; Karovska, Margarita

    2009-02-01

    We carried out a new and sensitive search for long-period variability in the prototype of the Mira class of long-period pulsating variables, o Ceti (Mira A), the closest and brightest Mira variable. We conducted this search using an unbroken light curve from 1902 to the present, assembled from the visual data archives of five major variable star observing organizations from around the world. We applied several time-series analysis techniques to search for two specific kinds of variability: long secondary periods (LSPs) longer than the dominant pulsation period of ~333 days, and long-term period variation in the dominant pulsation period itself. The data quality is sufficient to detect coherent periodic variations with photometric amplitudes of 0.05 mag or less. We do not find evidence for coherent LSPs in o Ceti to a limit of 0.1 mag, where the amplitude limit is set by intrinsic, stochastic, low-frequency variability of approximately 0.1 mag. We marginally detect a slight modulation of the pulsation period similar in timescale to that observed in the Miras with meandering periods, but with a much lower period amplitude of ±2 days. However, we do find clear evidence of a low-frequency power-law component in the Fourier spectrum of o Ceti's long-term light curve. The amplitude of this stochastic variability is approximately 0.1 mag at a period of 1000 days, and it exhibits a turnover for periods longer than this. This spectrum is similar to the red noise spectra observed in red supergiants.

  8. The dynamics of variable-density turbulence

    International Nuclear Information System (INIS)

    Sandoval, D.L.

    1995-11-01

    The dynamics of variable-density turbulent fluids are studied by direct numerical simulation. The flow is incompressible so that acoustic waves are decoupled from the problem, and implying that density is not a thermodynamic variable. Changes in density occur due to molecular mixing. The velocity field, is in general, divergent. A pseudo-spectral numerical technique is used to solve the equations of motion. Three-dimensional simulations are performed using a grid size of 128 3 grid points. Two types of problems are studied: (1) the decay of isotropic, variable-density turbulence, and (2) buoyancy-generated turbulence in a fluid with large density fluctuations. In the case of isotropic, variable-density turbulence, the overall statistical decay behavior, for the cases studied, is relatively unaffected by the presence of density variations when the initial density and velocity fields are statistically independent. The results for this case are in quantitative agreement with previous numerical and laboratory results. In this case, the initial density field has a bimodal probability density function (pdf) which evolves in time towards a Gaussian distribution. The pdf of the density field is symmetric about its mean value throughout its evolution. If the initial velocity and density fields are statistically dependent, however, the decay process is significantly affected by the density fluctuations. For the case of buoyancy-generated turbulence, variable-density departures from the Boussinesq approximation are studied. The results of the buoyancy-generated turbulence are compared with variable-density model predictions. Both a one-point (engineering) model and a two-point (spectral) model are tested against the numerical data. Some deficiencies in these variable-density models are discussed and modifications are suggested

  9. Conspicuous plumage colours are highly variable.

    Science.gov (United States)

    Delhey, Kaspar; Szecsenyi, Beatrice; Nakagawa, Shinichi; Peters, Anne

    2017-01-25

    Elaborate ornamental traits are often under directional selection for greater elaboration, which in theory should deplete underlying genetic variation. Despite this, many ornamental traits appear to remain highly variable and how this essential variation is maintained is a key question in evolutionary biology. One way to address this question is to compare differences in intraspecific variability across different types of traits to determine whether high levels of variation are associated with specific trait characteristics. Here we assess intraspecific variation in more than 100 plumage colours across 55 bird species to test whether colour variability is linked to their level of elaboration (indicated by degree of sexual dichromatism and conspicuousness) or their condition dependence (indicated by mechanism of colour production). Conspicuous colours had the highest levels of variation and conspicuousness was the strongest predictor of variability, with high explanatory power. After accounting for this, there were no significant effects of sexual dichromatism or mechanisms of colour production. Conspicuous colours may entail higher production costs or may be more sensitive to disruptions during production. Alternatively, high variability could also be related to increased perceptual difficulties inherent to discriminating highly elaborate colours. Such psychophysical effects may constrain the exaggeration of animal colours. © 2017 The Author(s).

  10. Gaia DR1 documentation Chapter 6: Variability

    Science.gov (United States)

    Eyer, L.; Rimoldini, L.; Guy, L.; Holl, B.; Clementini, G.; Cuypers, J.; Mowlavi, N.; Lecoeur-Taïbi, I.; De Ridder, J.; Charnas, J.; Nienartowicz, K.

    2017-12-01

    This chapter describes the photometric variability processing of the Gaia DR1 data. Coordination Unit 7 is responsible for the variability analysis of over a billion celestial sources. In particular the definition, design, development, validation and provision of a software package for the data processing of photometrically variable objects. Data Processing Centre Geneva (DPCG) responsibilities cover all issues related to the computational part of the CU7 analysis. These span: hardware provisioning, including selection, deployment and optimisation of suitable hardware, choosing and developing software architecture, defining data and scientific workflows as well as operational activities such as configuration management, data import, time series reconstruction, storage and processing handling, visualisation and data export. CU7/DPCG is also responsible for interaction with other DPCs and CUs, software and programming training for the CU7 members, scientific software quality control and management of software and data lifecycle. Details about the specific data treatment steps of the Gaia DR1 data products are found in Eyer et al. (2017) and are not repeated here. The variability content of the Gaia DR1 focusses on a subsample of Cepheids and RR Lyrae stars around the South ecliptic pole, showcasing the performance of the Gaia photometry with respect to variable objects.

  11. Visual variability affects early verb learning.

    Science.gov (United States)

    Twomey, Katherine E; Lush, Lauren; Pearce, Ruth; Horst, Jessica S

    2014-09-01

    Research demonstrates that within-category visual variability facilitates noun learning; however, the effect of visual variability on verb learning is unknown. We habituated 24-month-old children to a novel verb paired with an animated star-shaped actor. Across multiple trials, children saw either a single action from an action category (identical actions condition, for example, travelling while repeatedly changing into a circle shape) or multiple actions from that action category (variable actions condition, for example, travelling while changing into a circle shape, then a square shape, then a triangle shape). Four test trials followed habituation. One paired the habituated verb with a new action from the habituated category (e.g., 'dacking' + pentagon shape) and one with a completely novel action (e.g., 'dacking' + leg movement). The others paired a new verb with a new same-category action (e.g., 'keefing' + pentagon shape), or a completely novel category action (e.g., 'keefing' + leg movement). Although all children discriminated novel verb/action pairs, children in the identical actions condition discriminated trials that included the completely novel verb, while children in the variable actions condition discriminated the out-of-category action. These data suggest that - as in noun learning - visual variability affects verb learning and children's ability to form action categories. © 2014 The British Psychological Society.

  12. The variability of interconnected wind plants

    International Nuclear Information System (INIS)

    Katzenstein, Warren; Fertig, Emily; Apt, Jay

    2010-01-01

    We present the first frequency-dependent analyses of the geographic smoothing of wind power's variability, analyzing the interconnected measured output of 20 wind plants in Texas. Reductions in variability occur at frequencies corresponding to times shorter than ∼24 h and are quantified by measuring the departure from a Kolmogorov spectrum. At a frequency of 2.8x10 -4 Hz (corresponding to 1 h), an 87% reduction of the variability of a single wind plant is obtained by interconnecting 4 wind plants. Interconnecting the remaining 16 wind plants produces only an additional 8% reduction. We use step change analyses and correlation coefficients to compare our results with previous studies, finding that wind power ramps up faster than it ramps down for each of the step change intervals analyzed and that correlation between the power output of wind plants 200 km away is half that of co-located wind plants. To examine variability at very low frequencies, we estimate yearly wind energy production in the Great Plains region of the United States from automated wind observations at airports covering 36 years. The estimated wind power has significant inter-annual variability and the severity of wind drought years is estimated to be about half that observed nationally for hydroelectric power.

  13. VariableR Reclustering in Multiple Top Quark and W Boson Events

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, Jeremy [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-14

    VariableR jet reclustering is an innovative technique that allows for the reconstruction of boosted object over a wide range of kinematic regimes. Such capability enables the efficient identification of events with multiple boosted top quarks which is a typical signature for new physics processes such as the production of the supersymmetric partner of the gluon. In order to evaluate the performance of the algorithm, the VariableR reclustered jets are compared with fixed radius reclustered jets. The flexibility of the algorithm is tested by reconstructing both boosted top quarks and boosted W bosons. The VariableR reclustering method is found to be more efficient than the fixed radius algorithm at identifying top quarks and W bosons in events with four top quarks, therefore enhancing the sensitivity for gluino searches.

  14. Investigating Factorial Invariance of Latent Variables Across Populations When Manifest Variables Are Missing Completely.

    Science.gov (United States)

    Widaman, Keith F; Grimm, Kevin J; Early, Dawnté R; Robins, Richard W; Conger, Rand D

    2013-07-01

    Difficulties arise in multiple-group evaluations of factorial invariance if particular manifest variables are missing completely in certain groups. Ad hoc analytic alternatives can be used in such situations (e.g., deleting manifest variables), but some common approaches, such as multiple imputation, are not viable. At least 3 solutions to this problem are viable: analyzing differing sets of variables across groups, using pattern mixture approaches, and a new method using random number generation. The latter solution, proposed in this article, is to generate pseudo-random normal deviates for all observations for manifest variables that are missing completely in a given sample and then to specify multiple-group models in a way that respects the random nature of these values. An empirical example is presented in detail comparing the 3 approaches. The proposed solution can enable quantitative comparisons at the latent variable level between groups using programs that require the same number of manifest variables in each group.

  15. The Information Content of Financial and Economic Variables: Empirical Tests of Information Variables in Japan

    OpenAIRE

    Kengo Kato

    1991-01-01

    The main topic of this paper is "information variables" (or "indicators") of monetary policy, which work as criteria for setting the direction of monetary policy. After briefly surveying the notion and candidates of information variables, according to the studies mainly in the United States, empirical tests using Japan's data are conducted. It can be said that some information variables seem to be useful, but the results are mixed in general.

  16. Effects of short-term variability of meteorological variables on soil temperature in permafrost regions

    Science.gov (United States)

    Beer, Christian; Porada, Philipp; Ekici, Altug; Brakebusch, Matthias

    2018-03-01

    Effects of the short-term temporal variability of meteorological variables on soil temperature in northern high-latitude regions have been investigated. For this, a process-oriented land surface model has been driven using an artificially manipulated climate dataset. Short-term climate variability mainly impacts snow depth, and the thermal diffusivity of lichens and bryophytes. These impacts of climate variability on insulating surface layers together substantially alter the heat exchange between atmosphere and soil. As a result, soil temperature is 0.1 to 0.8 °C higher when climate variability is reduced. Earth system models project warming of the Arctic region but also increasing variability of meteorological variables and more often extreme meteorological events. Therefore, our results show that projected future increases in permafrost temperature and active-layer thickness in response to climate change will be lower (i) when taking into account future changes in short-term variability of meteorological variables and (ii) when representing dynamic snow and lichen and bryophyte functions in land surface models.

  17. Changes in heart rate variability and QT variability during the first trimester of pregnancy.

    Science.gov (United States)

    Carpenter, R E; D'Silva, L A; Emery, S J; Uzun, O; Rassi, D; Lewis, M J

    2015-03-01

    The risk of new-onset arrhythmia during pregnancy is high, presumably relating to changes in both haemodynamic and cardiac autonomic function. The ability to non-invasively assess an individual's risk of developing arrhythmia during pregnancy would therefore be clinically significant. We aimed to quantify electrocardiographic temporal characteristics during the first trimester of pregnancy and to compare these with non-pregnant controls. Ninety-nine pregnant women and sixty-three non-pregnant women underwent non-invasive cardiovascular and haemodynamic assessment during a protocol consisting of various physiological states (postural manoeurvres, light exercise and metronomic breathing). Variables measured included stroke volume, cardiac output, heart rate, heart rate variability, QT and QT variability and QTVI (a measure of the variability of QT relative to that of RR). Heart rate (p pregnancy only during the supine position (p pregnancy in all physiological states (p pregnancy in all states (p pregnancy is associated with substantial changes in heart rate variability, reflecting a reduction in parasympathetic tone and an increase in sympathetic activity. QTVI shifted to a less favourable value, reflecting a greater than normal amount of QT variability. QTVI appears to be a useful method for quantifying changes in QT variability relative to RR (or heart rate) variability, being sensitive not only to physiological state but also to gestational age. We support the use of non-invasive markers of cardiac electrical variability to evaluate the risk of arrhythmic events in pregnancy, and we recommend the use of multiple physiological states during the assessment protocol.

  18. Impact of Subsurface Temperature Variability on Meteorological Variability: An AGCM Study

    Science.gov (United States)

    Mahanama, S. P.; Koster, R. D.; Liu, P.

    2006-05-01

    Anomalous atmospheric conditions can lead to surface temperature anomalies, which in turn can lead to temperature anomalies deep in the soil. The deep soil temperature (and the associated ground heat content) has significant memory -- the dissipation of a temperature anomaly may take weeks to months -- and thus deep soil temperature may contribute to the low frequency variability of energy and water variables elsewhere in the system. The memory may even provide some skill to subseasonal and seasonal forecasts. This study uses two long-term AGCM experiments to isolate the contribution of deep soil temperature variability to variability elsewhere in the climate system. The first experiment consists of a standard ensemble of AMIP-type simulations, simulations in which the deep soil temperature variable is allowed to interact with the rest of the system. In the second experiment, the coupling of the deep soil temperature to the rest of the climate system is disabled -- at each grid cell, the local climatological seasonal cycle of deep soil temperature (as determined from the first experiment) is prescribed. By comparing the variability of various atmospheric quantities as generated in the two experiments, we isolate the contribution of interactive deep soil temperature to that variability. The results show that interactive deep soil temperature contributes significantly to surface temperature variability. Interactive deep soil temperature, however, reduces the variability of the hydrological cycle (evaporation and precipitation), largely because it allows for a negative feedback between evaporation and temperature.

  19. Scalable conditional induction variables (CIV) analysis

    DEFF Research Database (Denmark)

    Oancea, Cosmin Eugen; Rauchwerger, Lawrence

    2015-01-01

    parallelizing compiler and evaluated its impact on five Fortran benchmarks. We have found that that there are many important loops using CIV subscripts and that our analysis can lead to their scalable parallelization. This in turn has led to the parallelization of the benchmark programs they appear in.......Subscripts using induction variables that cannot be expressed as a formula in terms of the enclosing-loop indices appear in the low-level implementation of common programming abstractions such as filter, or stack operations and pose significant challenges to automatic parallelization. Because...... the complexity of such induction variables is often due to their conditional evaluation across the iteration space of loops we name them Conditional Induction Variables (CIV). This paper presents a flow-sensitive technique that summarizes both such CIV-based and affine subscripts to program level, using the same...

  20. Search for rapid variability of 53 Cam

    International Nuclear Information System (INIS)

    Zverko, J.

    1982-01-01

    Photoelectric observations of magnetic Ap star 53 Cam made at the Skalnate Pleso Observatory in 1978 and 1979 are analyzed from the point of view of rapid variability. The observations were made with an intermediate passband filter, effective wavelength 526 nm. Besides the differences msub(53Cam)-msub(Comp), the behaviour was also investigated of the deflections for the comparison star during the observation runs. A strong correlation between the behaviour of the comparison and variable star light curve was found and the appearance differs from night to night depending on atmospheric conditions. Each observation run is analyzed in detail and it was concluded that all observed variations are only apparent and due to the variability of atmospheric extinction above the observation site. (author)

  1. Harmonic and complex analysis in several variables

    CERN Document Server

    Krantz, Steven G

    2017-01-01

    Authored by a ranking authority in harmonic analysis of several complex variables, this book embodies a state-of-the-art entrée at the intersection of two important fields of research: complex analysis and harmonic analysis. Written with the graduate student in mind, it is assumed that the reader has familiarity with the basics of complex analysis of one and several complex variables as well as with real and functional analysis. The monograph is largely self-contained and develops the harmonic analysis of several complex variables from the first principles. The text includes copious examples, explanations, an exhaustive bibliography for further reading, and figures that illustrate the geometric nature of the subject. Each chapter ends with an exercise set. Additionally, each chapter begins with a prologue, introducing the reader to the subject matter that follows; capsules presented in each section give perspective and a spirited launch to the segment; preludes help put ideas into context. Mathematicians and...

  2. Penalized variable selection in competing risks regression.

    Science.gov (United States)

    Fu, Zhixuan; Parikh, Chirag R; Zhou, Bingqing

    2017-07-01

    Penalized variable selection methods have been extensively studied for standard time-to-event data. Such methods cannot be directly applied when subjects are at risk of multiple mutually exclusive events, known as competing risks. The proportional subdistribution hazard (PSH) model proposed by Fine and Gray (J Am Stat Assoc 94:496-509, 1999) has become a popular semi-parametric model for time-to-event data with competing risks. It allows for direct assessment of covariate effects on the cumulative incidence function. In this paper, we propose a general penalized variable selection strategy that simultaneously handles variable selection and parameter estimation in the PSH model. We rigorously establish the asymptotic properties of the proposed penalized estimators and modify the coordinate descent algorithm for implementation. Simulation studies are conducted to demonstrate the good performance of the proposed method. Data from deceased donor kidney transplants from the United Network of Organ Sharing illustrate the utility of the proposed method.

  3. Rapid variability of extragalactic radio sources

    Energy Technology Data Exchange (ETDEWEB)

    Quirrenbach, A.; Witzel, A.; Krichbaum, T.; Hummel, C.A.; Alberdi, A.; Schalinski, C.

    1989-02-02

    Since its discovery more than 20 years ago, variability of extragalactic radio sources on timescales of weeks to years has been the subject of many investigations. We have examined the variability of these sources on timescales of hours at wavelengths of 6 and 11 cm using the 100-m telescope of the Max-Planck-Institut fuer Radioastronomie and report the results for two sources. The quasar QSO0917 + 62 showed variations with amplitudes of up to 23% in /similar to/ 24 hours, which were correlated at the two wavelengths; in the BL Lac object 0716 + 71 we found variations with amplitudes of 7-11%. We discuss intrinsic effects, gravitational lensing and scattering in the interstellar medium as possible explanations for rapid radio variability.

  4. Measuring Variability in the Presence of Noise

    Science.gov (United States)

    Welsh, W. F.

    Quantitative measurements of a variable signal in the presence of noise requires very careful attention to subtle affects which can easily bias the measurements. This is not limited to the low-count rate regime, nor is the bias error necessarily small. In this talk I will mention some of the dangers in applying standard techniques which are appropriate for high signal to noise data but fail in the cases where the S/N is low. I will discuss methods for correcting the bias in the these cases, both for periodic and non-periodic variability, and will introduce the concept of the ``filtered de-biased RMS''. I will also illustrate some common abuses of power spectrum interpretation. All of these points will be illustrated with examples from recent work on CV and AGN variability.

  5. Dynamics of mechanical systems with variable mass

    CERN Document Server

    Belyaev, Alexander

    2014-01-01

    The book presents up-to-date and unifying formulations for treating dynamics of different types of mechanical systems with variable mass. The starting point is overview of the continuum mechanics relations of balance and jump for open systems from which extended Lagrange and Hamiltonian formulations are derived. Corresponding approaches are stated at the level of analytical mechanics with emphasis on systems with a position-dependent mass and at the level of structural mechanics. Special emphasis is laid upon axially moving structures like belts and chains, and on pipes with an axial flow of fluid. Constitutive relations in the dynamics of systems with variable mass are studied with particular reference to modeling of multi-component mixtures. The dynamics of machines with a variable mass are treated in detail and conservation laws and the stability of motion will be analyzed. Novel finite element formulations for open systems in coupled fluid and structural dynamics are presented.

  6. Structure and Evolution of Magnetic Cataclysmic Variables

    Science.gov (United States)

    Andronov, I. L.

    2007-06-01

    Theoretical models and observational results are reviewed. The general picture of the structure and evolution of cataclysmic variables (CV) is presented, together with a brief discussion of additional mechanisms of intrinsic variability of the components and magnetic activity of secondaries. Special attention is paid to the accretion structures - flow, disk, column - which are affected by the magnetic field of the white dwarf. The mass and angular momentum transfer in asynchronous MCVs leads to a "propeller" stage of rapid synchronization, after which the "idlings" of the white dwarf are altered to "swingings" with a characteristic time of century(ies). The disk- magnetic field interaction leads to precession of the white dwarf, which causes quasi-periodic changes of the equilibrium rotational period. "Shot noise" in cataclysmic variables is discussed based on one-bandpass and multi-color observations.

  7. 40 Variability Bugs in the Linux Kernel

    DEFF Research Database (Denmark)

    Abal Rivas, Iago; Brabrand, Claus; Wasowski, Andrzej

    2014-01-01

    Feature-sensitive verification is a recent field that pursues the effective analysis of the exponential number of variants of a program family. Today researchers lack examples of concrete bugs induced by variability, and occurring in real large-scale software. Such a collection of bugs is a requi......Feature-sensitive verification is a recent field that pursues the effective analysis of the exponential number of variants of a program family. Today researchers lack examples of concrete bugs induced by variability, and occurring in real large-scale software. Such a collection of bugs...... the outcome of our analysis into a database. In addition, we provide self-contained simplified C99 versions of the bugs, facilitating understanding and tool evaluation. Our study provides insights about the nature and occurrence of variability bugs in a large C software system, and shows in what ways...

  8. Evolving spiking networks with variable resistive memories.

    Science.gov (United States)

    Howard, Gerard; Bull, Larry; de Lacy Costello, Ben; Gale, Ella; Adamatzky, Andrew

    2014-01-01

    Neuromorphic computing is a brainlike information processing paradigm that requires adaptive learning mechanisms. A spiking neuro-evolutionary system is used for this purpose; plastic resistive memories are implemented as synapses in spiking neural networks. The evolutionary design process exploits parameter self-adaptation and allows the topology and synaptic weights to be evolved for each network in an autonomous manner. Variable resistive memories are the focus of this research; each synapse has its own conductance profile which modifies the plastic behaviour of the device and may be altered during evolution. These variable resistive networks are evaluated on a noisy robotic dynamic-reward scenario against two static resistive memories and a system containing standard connections only. The results indicate that the extra behavioural degrees of freedom available to the networks incorporating variable resistive memories enable them to outperform the comparative synapse types.

  9. Rapid variability of extragalactic radio sources

    International Nuclear Information System (INIS)

    Quirrenbach, A.; Witzel, A.; Krichbaum, T.; Hummel, C.A.; Alberdi, A.; Schalinski, C.

    1989-01-01

    Since its discovery more than 20 years ago, variability of extragalactic radio sources on timescales of weeks to years has been the subject of many investigations. We have examined the variability of these sources on timescales of hours at wavelengths of 6 and 11 cm using the 100-m telescope of the Max-Planck-Institut fuer Radioastronomie and report the results for two sources. The quasar QSO0917 + 62 showed variations with amplitudes of up to 23% in ∼ 24 hours, which were correlated at the two wavelengths; in the BL Lac object 0716 + 71 we found variations with amplitudes of 7-11%. We discuss intrinsic effects, gravitational lensing and scattering in the interstellar medium as possible explanations for rapid radio variability. (author)

  10. Imaging Brain Development: Benefiting from Individual Variability

    Directory of Open Access Journals (Sweden)

    Megha Sharda

    2015-01-01

    Full Text Available Human brain development is a complex process that evolves from early childhood to young adulthood. Major advances in brain imaging are increasingly being used to characterize the developing brain. These advances have further helped to elucidate the dynamic maturational processes that lead to the emergence of complex cognitive abilities in both typical and atypical development. However, conventional approaches involve categorical group comparison models and tend to disregard the role of widespread interindividual variability in brain development. This review highlights how this variability can inform our understanding of developmental processes. The latest studies in the field of brain development are reviewed, with a particular focus on the role of individual variability and the consequent heterogeneity in brain structural and functional development. This review also highlights how such heterogeneity might be utilized to inform our understanding of complex neuropsychiatric disorders and recommends the use of more dimensional approaches to study brain development.

  11. Clinical and acoustical variability in hypokinetic dysarthria

    International Nuclear Information System (INIS)

    Metter, E.J.; Hanson, W.R.

    1986-01-01

    Ten male patients with parkinsonism secondary to Parkinson's disease or progressive supranuclear palsy had clinical neurological, speech, and acoustical speech evaluations. In addition, seven of the patients were evaluated by x-ray computed tomography (CT) and (F-18)-fluorodeoxyglucose (FDG) positron emission tomography (PET). Extensive variability of speech features, both clinical and acoustical, were found and seemed to be independent of the severity of any parkinsonian sign, CT, or FDG PET. In addition, little relationship existed between the variability across each measured speech feature. What appeared to be important for the appearance of abnormal acoustic measures was the degree of overall severity of the dysarthria. These observations suggest that a better understanding of hypokinetic dysarthria may result from more extensive examination of the variability between patients. Emphasizing a specific feature such as rapid speaking rate in characterizing hypokinetic dysarthria focuses on a single and inconstant finding in a complex speech pattern

  12. Variability of the Wind Turbine Power Curve

    Directory of Open Access Journals (Sweden)

    Mahesh M. Bandi

    2016-09-01

    Full Text Available Wind turbine power curves are calibrated by turbine manufacturers under requirements stipulated by the International Electrotechnical Commission to provide a functional mapping between the mean wind speed v ¯ and the mean turbine power output P ¯ . Wind plant operators employ these power curves to estimate or forecast wind power generation under given wind conditions. However, it is general knowledge that wide variability exists in these mean calibration values. We first analyse how the standard deviation in wind speed σ v affects the mean P ¯ and the standard deviation σ P of wind power. We find that the magnitude of wind power fluctuations scales as the square of the mean wind speed. Using data from three planetary locations, we find that the wind speed standard deviation σ v systematically varies with mean wind speed v ¯ , and in some instances, follows a scaling of the form σ v = C × v ¯ α ; C being a constant and α a fractional power. We show that, when applicable, this scaling form provides a minimal parameter description of the power curve in terms of v ¯ alone. Wind data from different locations establishes that (in instances when this scaling exists the exponent α varies with location, owing to the influence of local environmental conditions on wind speed variability. Since manufacturer-calibrated power curves cannot account for variability influenced by local conditions, this variability translates to forecast uncertainty in power generation. We close with a proposal for operators to perform post-installation recalibration of their turbine power curves to account for the influence of local environmental factors on wind speed variability in order to reduce the uncertainty of wind power forecasts. Understanding the relationship between wind’s speed and its variability is likely to lead to lower costs for the integration of wind power into the electric grid.

  13. Examining impulse-variability in overarm throwing.

    Science.gov (United States)

    Urbin, M A; Stodden, David; Boros, Rhonda; Shannon, David

    2012-01-01

    The purpose of this study was to examine variability in overarm throwing velocity and spatial output error at various percentages of maximum to test the prediction of an inverted-U function as predicted by impulse-variability theory and a speed-accuracy trade-off as predicted by Fitts' Law Thirty subjects (16 skilled, 14 unskilled) were instructed to throw a tennis ball at seven percentages of their maximum velocity (40-100%) in random order (9 trials per condition) at a target 30 feet away. Throwing velocity was measured with a radar gun and interpreted as an index of overall systemic power output. Within-subject throwing velocity variability was examined using within-subjects repeated-measures ANOVAs (7 repeated conditions) with built-in polynomial contrasts. Spatial error was analyzed using mixed model regression. Results indicated a quadratic fit with variability in throwing velocity increasing from 40% up to 60%, where it peaked, and then decreasing at each subsequent interval to maximum (p < .001, η2 = .555). There was no linear relationship between speed and accuracy. Overall, these data support the notion of an inverted-U function in overarm throwing velocity variability as both skilled and unskilled subjects approach maximum effort. However, these data do not support the notion of a speed-accuracy trade-off. The consistent demonstration of an inverted-U function associated with systemic power output variability indicates an enhanced capability to regulate aspects of force production and relative timing between segments as individuals approach maximum effort, even in a complex ballistic skill.

  14. Variable stiffness and damping MR isolator

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X Z; Wang, X Y; Li, W H; Kostidis, K [University of Wollongong, School of Mechanical, Materials and Mechatronic Engineering, NSW 2522 (Australia)], E-mail: weihuali@uow.edu.au

    2009-02-01

    This paper presents the development of a magnetorheological (MR) fluid-based variable stiffness and damping isolator for vibration suppressions. The MR fluid isolator used a sole MR control unit to achieve the variable stiffness and damping in stepless and relative large scope. A mathematical model of the isolator was derived, and a prototype of the MR fluid isolator was fabricated and its dynamic behavior was measured in vibration under various applied magnetic fields. The parameters of the model under various magnetic fields were identified and the dynamic performances of isolator were evaluated.

  15. Photometry of red variables in 47 Tucanae

    International Nuclear Information System (INIS)

    Fox, M.W.

    1982-01-01

    BVRI observations of known and suspected variables in the globular cluster 47 Tuc are described. Twelve period determinations were made, seven of which are new. The non-Mira stars are found to vary in a semi-regular manner, regardless of period. Values of Tsub(eff), Msub(bol) and Q, the pulsation constant, are derived by combining the BVRI with JHKL observations made near the same epoch. The results strongly favour pulsation in an overtone mode for both the Mira and semi-regular variables in 47 Tuc. There is also evidence of mode 'switching' for V4. (author)

  16. Robust cluster analysis and variable selection

    CERN Document Server

    Ritter, Gunter

    2014-01-01

    Clustering remains a vibrant area of research in statistics. Although there are many books on this topic, there are relatively few that are well founded in the theoretical aspects. In Robust Cluster Analysis and Variable Selection, Gunter Ritter presents an overview of the theory and applications of probabilistic clustering and variable selection, synthesizing the key research results of the last 50 years. The author focuses on the robust clustering methods he found to be the most useful on simulated data and real-time applications. The book provides clear guidance for the varying needs of bot

  17. Lectures on counterexamples in several complex variables

    CERN Document Server

    Fornæss, John Erik

    2007-01-01

    Counterexamples are remarkably effective for understanding the meaning, and the limitations, of mathematical results. Fornæss and Stensønes look at some of the major ideas of several complex variables by considering counterexamples to what might seem like reasonable variations or generalizations. The first part of the book reviews some of the basics of the theory, in a self-contained introduction to several complex variables. The counterexamples cover a variety of important topics: the Levi problem, plurisubharmonic functions, Monge-Ampère equations, CR geometry, function theory, and the \\bar\\

  18. Function theory of several complex variables

    CERN Document Server

    Krantz, Steven G

    2001-01-01

    The theory of several complex variables can be studied from several different perspectives. In this book, Steven Krantz approaches the subject from the point of view of a classical analyst, emphasizing its function-theoretic aspects. He has taken particular care to write the book with the student in mind, with uniformly extensive and helpful explanations, numerous examples, and plentiful exercises of varying difficulty. In the spirit of a student-oriented text, Krantz begins with an introduction to the subject, including an insightful comparison of analysis of several complex variables with th

  19. An assessment of variability in radiocarbon dating

    International Nuclear Information System (INIS)

    Scott, E.M.; Baxter, M.S.; Aitchison, T.C.

    1981-01-01

    A series of replicate experiments, involving analysis of homogenized wood and identical tree-ring sections, suggests that the 14 C counting error in radiocarbon dating quantifies only part of the total variability of measurement. Statistical modelling implies that a more realistic assessment of error is provided by a value approximately three times the counting error. The incorporation of this more realistic measure of variability into an appropriate procedure for calibrating a single date and for matching a floating chronology to a master chronology is described. (author)

  20. Multiple variables data sets visualization in ROOT

    International Nuclear Information System (INIS)

    Couet, O

    2008-01-01

    The ROOT graphical framework provides support for many different functions including basic graphics, high-level visualization techniques, output on files, 3D viewing etc. They use well-known world standards to render graphics on screen, to produce high-quality output files, and to generate images for Web publishing. Many techniques allow visualization of all the basic ROOT data types, but the graphical framework was still a bit weak in the visualization of multiple variables data sets. This paper presents latest developments done in the ROOT framework to visualize multiple variables (>4) data sets

  1. Cepheid pulsation theory and multiperiodic cepheid variables

    International Nuclear Information System (INIS)

    Cox, A.N.; Cox, J.P.

    1975-01-01

    In this review of the multiperiodic Cepheid variables, the subject matter is divided into four parts. The first discusses general causes of pulsation of Cepheids and other variable stars, and their locations on the H-R diagram. In the second section, the linear adiabatic and nonadiabatic theory calculation of radial pulsation periods and their application to the problem of masses and double-mode Cepheids are reviewed. Periodic solutions, and their stability, of the nonlinear radial pulsation equations for Cepheids and RR Lyrae stars are considered in the third section. The last section provides the latest results on nonlinear, nonperiodic, radial pulsations for Cepheids and RR Lyrae stars. (BJG)

  2. Gaussian Mixture Model of Heart Rate Variability

    Science.gov (United States)

    Costa, Tommaso; Boccignone, Giuseppe; Ferraro, Mario

    2012-01-01

    Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters. PMID:22666386

  3. Additive measures of travel time variability

    DEFF Research Database (Denmark)

    Engelson, Leonid; Fosgerau, Mogens

    2011-01-01

    This paper derives a measure of travel time variability for travellers equipped with scheduling preferences defined in terms of time-varying utility rates, and who choose departure time optimally. The corresponding value of travel time variability is a constant that depends only on preference...... parameters. The measure is unique in being additive with respect to independent parts of a trip. It has the variance of travel time as a special case. Extension is provided to the case of travellers who use a scheduled service with fixed headway....

  4. Collective Variables in Apphed Linguistics Research

    OpenAIRE

    ヘンスリー, ジョール; HENSLEY, Joel

    2011-01-01

    This paper focuses on the key dynamic(al)systems theory concept of collective variables as it relates to developmental research in applied linguistics. Dynamic(al) systems theory is becoming prevalent in linguistic research and in the past two decades has jumped to the forefront of cutting edge in the field. One key concept in dynamic(al) systems theory is that of collective variables. In order to help properly orient this concept in the field of applied linguistics, this paper discusses the ...

  5. Variable ordering structures in vector optimization

    CERN Document Server

    Eichfelder, Gabriele

    2014-01-01

    This book provides an introduction to vector optimization with variable ordering structures, i.e., to optimization problems with a vector-valued objective function where the elements in the objective space are compared based on a variable ordering structure: instead of a partial ordering defined by a convex cone, we see a whole family of convex cones, one attached to each element of the objective space. The book starts by presenting several applications that have recently sparked new interest in these optimization problems, and goes on to discuss fundamentals and important results on a wide ra

  6. Response-rate differences in variable-interval and variable-ratio schedules: An old problem revisited

    OpenAIRE

    Cole, Mark R.

    1994-01-01

    In Experiment 1, a variable-ratio 10 schedule became, successively, a variable-interval schedule with only the minimum interreinforcement intervals yoked to the variable ratio, or a variable-interval schedule with both interreinforcement intervals and reinforced interresponse times yoked to the variable ratio. Response rates in the variable-interval schedule with both interreinforcement interval and reinforced interresponse time yoking fell between the higher rates maintained by the variable-...

  7. Environmental Variables and Pupils' Academic Performance in ...

    African Journals Online (AJOL)

    This causal-comparative study was carried out to investigate the influence of environmental variables on pupils' academic performance in primary science in Cross River State, Nigeria. Three hypotheses were formulated to guide the study. Two instruments were used to collect data for the study namely: environmental ...

  8. Bell inequalities for continuous-variable measurements

    International Nuclear Information System (INIS)

    He, Q. Y.; Reid, M. D.; Drummond, P. D.; Cavalcanti, E. G.

    2010-01-01

    Tests of local hidden-variable theories using measurements with continuous-variable (CV) outcomes are developed, and a comparison of different methods is presented. As examples, we focus on multipartite entangled Greenberger-Horne-Zeilinger and cluster states. We suggest a physical process that produces the states proposed here, and investigate experiments both with and without binning of the continuous variable. In the former case, the Mermin-Klyshko inequalities can be used directly. For unbinned outcomes, the moment-based Cavalcanti-Foster-Reid-Drummond inequalities are extended to functional inequalities by consideration of arbitrary functions of the measurements at each site. By optimizing these functions, we obtain more robust violations of local hidden-variable theories than with either binning or moments. Recent inequalities based on the algebra of quaternions and octonions are compared with these methods. Since the prime advantage of CV experiments is to provide a route to highly efficient detection via homodyne measurements, we analyze the effect of noise and detection losses in both binned and unbinned cases. The CV moment inequalities with an optimal function have greater robustness to both loss and noise. This could permit a loophole-free test of Bell inequalities.

  9. Temperature variability over the tropical middle atmosphere

    Directory of Open Access Journals (Sweden)

    K. Mohanakumar

    1994-04-01

    Full Text Available A study on the variability of temperature in the tropical middle atmosphere over Thumba (8 32' N, 76 52' E, located at the southern part of India, has been carried out based on rocket observations for a period of 20 years, extending from 1970 to 1990. The rocketsonde-derived mean temperatures over Thumba are corrected prior to 1978 and then compared with the middle atmospheric reference model developed from satellite observations and Solar Mesosphere Explorer (SME satellite data. Temperature variability at every 1 km interval in the 25-75 km region was analysed. The tropical stratosphere is found to be highly stable, whereas considerable variability is noted in the middle mesosphere. The effect of seasonal cycle is least in the lower stratosphere. Annual and semi-annual oscillations in temperature are the primary oscillations in the tropical middle atmosphere. Annual temperature oscillations are dominant in the mesosphere and semi-annual oscillations are strong in the stratosphere. The stratopause region is noted to be the part of the middle atmosphere least sensitive to the changes in solar activity and long-term variability.

  10. Climate Change and Variability in Ghana: Stocktaking

    Directory of Open Access Journals (Sweden)

    Felix A. Asante

    2014-12-01

    Full Text Available This paper provides a holistic literature review of climate change and variability in Ghana by examining the impact and projections of climate change and variability in various sectors (agricultural, health and energy and its implication on ecology, land use, poverty and welfare. The findings suggest that there is a projected high temperature and low rainfall in the years 2020, 2050 and 2080, and desertification is estimated to be proceeding at a rate of 20,000 hectares per annum. Sea-surface temperatures will increase in Ghana’s waters and this will have drastic effects on fishery. There will be a reduction in the suitability of weather within the current cocoa-growing areas in Ghana by 2050 and an increase evapotranspiration of the cocoa trees. Furthermore, rice and rooted crops (especially cassava production are expected to be low. Hydropower generation is also at risk and there will be an increase in the incidence rate of measles, diarrheal cases, guinea worm infestation, malaria, cholera, cerebro-spinal meningitis and other water related diseases due to the current climate projections and variability. These negative impacts of climate change and variability worsens the plight of the poor, who are mostly women and children.

  11. Problems Identifying Independent and Dependent Variables

    Science.gov (United States)

    Leatham, Keith R.

    2012-01-01

    This paper discusses one step from the scientific method--that of identifying independent and dependent variables--from both scientific and mathematical perspectives. It begins by analyzing an episode from a middle school mathematics classroom that illustrates the need for students and teachers alike to develop a robust understanding of…

  12. Benford's law and continuous dependent random variables

    Science.gov (United States)

    Becker, Thealexa; Burt, David; Corcoran, Taylor C.; Greaves-Tunnell, Alec; Iafrate, Joseph R.; Jing, Joy; Miller, Steven J.; Porfilio, Jaclyn D.; Ronan, Ryan; Samranvedhya, Jirapat; Strauch, Frederick W.; Talbut, Blaine

    2018-01-01

    Many mathematical, man-made and natural systems exhibit a leading-digit bias, where a first digit (base 10) of 1 occurs not 11% of the time, as one would expect if all digits were equally likely, but rather 30%. This phenomenon is known as Benford's Law. Analyzing which datasets adhere to Benford's Law and how quickly Benford behavior sets in are the two most important problems in the field. Most previous work studied systems of independent random variables, and relied on the independence in their analyses. Inspired by natural processes such as particle decay, we study the dependent random variables that emerge from models of decomposition of conserved quantities. We prove that in many instances the distribution of lengths of the resulting pieces converges to Benford behavior as the number of divisions grow, and give several conjectures for other fragmentation processes. The main difficulty is that the resulting random variables are dependent. We handle this by using tools from Fourier analysis and irrationality exponents to obtain quantified convergence rates as well as introducing and developing techniques to measure and control the dependencies. The construction of these tools is one of the major motivations of this work, as our approach can be applied to many other dependent systems. As an example, we show that the n ! entries in the determinant expansions of n × n matrices with entries independently drawn from nice random variables converges to Benford's Law.

  13. Correlation between some environmental variables and abundance ...

    African Journals Online (AJOL)

    Correlation between some environmental variables and abundance of Almophrya mediovacuolata (Ciliophora: Anoplophryidae) endocommensal ciliate of an ... The survey primarily involved soil samples collection from the same spots of EW collection and preparation for physico-chemical analysis; evaluation in situ of the ...

  14. Extinction-Induced Variability in Human Behavior

    Science.gov (United States)

    Kinloch, Jennifer M.; Foster, T. Mary; McEwan, James S. A.

    2009-01-01

    Participants earned points by pressing a computer space bar (Experiment 1) or forming rectangles on the screen with the mouse (Experiment 2) under differential-reinforcement-of-low-rate schedules, followed by extinction. Variability in interresponse time (the contingent dimension) increased during extinction, as for Morgan and Lee (1996);…

  15. Sources of Variability in Children's Drawings

    Science.gov (United States)

    Simon, Lia; Stokes, Patricia D.

    2015-01-01

    An experiment involving 90 students in the 1st, 3rd, and 5th grades investigated how visual examples and grade (our surrogate for age) affected variability in a drawing task. The task involved using circles as the main element in a set of drawings. There were two examples: One was simple and single (a smiley face inside a circle); the other,…

  16. The global variability of diatomaceous earth toxicity

    DEFF Research Database (Denmark)

    Nattrass, C; Horwell, C J; Damby, D E

    2015-01-01

    BACKGROUND: Diatomaceous earth (DE) is mined globally and is potentially of occupational respiratory health concern due to the high crystalline silica content in processed material. DE toxicity, in terms of variability related to global source and processing technique, is poorly understood...

  17. Variable Speed Limit (VSL) - Best Management Practice

    Science.gov (United States)

    2012-07-01

    The Variable Speed Limit (VSL) system on the I-4 corridor in Orlando was implemented by Florida Department of Transportation in 2008, and since its deployment, it was revealed that the majority of traffic exceeds the speed limit by more mph when the ...

  18. Predictor variable resolution governs modeled soil types

    Science.gov (United States)

    Soil mapping identifies different soil types by compressing a unique suite of spatial patterns and processes across multiple spatial scales. It can be quite difficult to quantify spatial patterns of soil properties with remotely sensed predictor variables. More specifically, matching the right scale...

  19. Singular Linear Differential Equations in Two Variables

    NARCIS (Netherlands)

    Braaksma, B.L.J.; Put, M. van der

    2008-01-01

    The formal and analytic classification of integrable singular linear differential equations has been studied among others by R. Gerard and Y. Sibuya. We provide a simple proof of their main result, namely: For certain irregular systems in two variables there is no Stokes phenomenon, i.e. there is no

  20. Discrete variable representation for singular Hamiltonians

    DEFF Research Database (Denmark)

    Schneider, B. I.; Nygaard, Nicolai

    2004-01-01

    We discuss the application of the discrete variable representation (DVR) to Schrodinger problems which involve singular Hamiltonians. Unlike recent authors who invoke transformations to rid the eigenvalue equation of singularities at the cost of added complexity, we show that an approach based...

  1. Phenotypic Variability in the Coccolithophore Emiliania huxleyi.

    Science.gov (United States)

    Blanco-Ameijeiras, Sonia; Lebrato, Mario; Stoll, Heather M; Iglesias-Rodriguez, Debora; Müller, Marius N; Méndez-Vicente, Ana; Oschlies, Andreas

    2016-01-01

    Coccolithophores are a vital part of oceanic phytoplankton assemblages that produce organic matter and calcium carbonate (CaCO3) containing traces of other elements (i.e. Sr and Mg). Their associated carbon export from the euphotic zone to the oceans' interior plays a crucial role in CO2 feedback mechanisms and biogeochemical cycles. The coccolithophore Emiliania huxleyi has been widely studied as a model organism to understand physiological, biogeochemical, and ecological processes in marine sciences. Here, we show the inter-strain variability in physiological and biogeochemical traits in 13 strains of E. huxleyi from various biogeographical provinces obtained from culture collections commonly used in the literature. Our results demonstrate that inter-strain genetic variability has greater potential to induce larger phenotypic differences than the phenotypic plasticity of single strains cultured under a broad range of variable environmental conditions. The range of variation found in physiological parameters and calcite Sr:Ca highlights the need to reconsider phenotypic variability in paleoproxy calibrations and model parameterizations to adequately translate findings from single strain laboratory experiments to the real ocean.

  2. Phenotypic Variability in the Coccolithophore Emiliania huxleyi.

    Directory of Open Access Journals (Sweden)

    Sonia Blanco-Ameijeiras

    Full Text Available Coccolithophores are a vital part of oceanic phytoplankton assemblages that produce organic matter and calcium carbonate (CaCO3 containing traces of other elements (i.e. Sr and Mg. Their associated carbon export from the euphotic zone to the oceans' interior plays a crucial role in CO2 feedback mechanisms and biogeochemical cycles. The coccolithophore Emiliania huxleyi has been widely studied as a model organism to understand physiological, biogeochemical, and ecological processes in marine sciences. Here, we show the inter-strain variability in physiological and biogeochemical traits in 13 strains of E. huxleyi from various biogeographical provinces obtained from culture collections commonly used in the literature. Our results demonstrate that inter-strain genetic variability has greater potential to induce larger phenotypic differences than the phenotypic plasticity of single strains cultured under a broad range of variable environmental conditions. The range of variation found in physiological parameters and calcite Sr:Ca highlights the need to reconsider phenotypic variability in paleoproxy calibrations and model parameterizations to adequately translate findings from single strain laboratory experiments to the real ocean.

  3. Study of event shape variables at LEP

    CERN Document Server

    Sarkar, Subir

    1997-01-01

    We present the LEP results on the study of the hadronic event shape variables. Excellent detector performance and improved theoretical calculations make it possible to study quantum chromodynamics with small experimental and theoretical uncertainties. QCD predictions describe data well at energies above the Z peak.

  4. The textbook as classroom context variable

    NARCIS (Netherlands)

    Krammer, H.P.M.

    1985-01-01

    To explore the role of the textbook as a context variable in process—product relationships, data on teaching practices and learning outcomes from the IEA Classroom Environment Study in The Netherlands were used. The sample consisted of 50 secondary school mathematics classes and their teachers.

  5. Polynomial Variables and the Jacobian Problem

    Indian Academy of Sciences (India)

    algebra and algebraic geometry, and ... algebraically, to making the change of variables (X, Y) r--t. (X +p, Y ... aX + bY + p and eX + dY + q are linear polynomials in X, Y. ..... [5] T T Moh, On the Jacobian conjecture and the confipration of roots,.

  6. Fractal Structures For Mems Variable Capacitors

    KAUST Repository

    Elshurafa, Amro M.

    2014-08-28

    In accordance with the present disclosure, one embodiment of a fractal variable capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure, wherein the capacitor body has an upper first metal plate with a fractal shape separated by a vertical distance from a lower first metal plate with a complementary fractal shape; and a substrate above which the capacitor body is suspended.

  7. Continuous Variables Quantum Information in Noisy Environments

    DEFF Research Database (Denmark)

    Berni, Adriano

    safe from the detrimental effects of noise and losses. In the present work we investigate continuous variables Gaussian quantum information in noisy environments, studying the effects of various noise sources in the cases of a quantum metrological task, an error correction scheme and discord...

  8. Estimation of biochemical variables using quantumbehaved particle ...

    African Journals Online (AJOL)

    To generate a more efficient neural network estimator, we employed the previously proposed quantum-behaved particle swarm optimization (QPSO) algorithm for neural network training. The experiment results of L-glutamic acid fermentation process showed that our established estimator could predict variables such as the ...

  9. Teachers' classroom management variables and students' academic ...

    African Journals Online (AJOL)

    Teachers' classroom management variables and students' academic achievement in French in Cross River State, Nigeria. JU Emeh, CA Agbor. Abstract. No Abstract. Global Journal of Humanities Vol. 4(1&2) 2005: 25-27. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD ...

  10. Do psychological variables affect early surgical recovery?

    Directory of Open Access Journals (Sweden)

    Michael N Mavros

    Full Text Available BACKGROUND: Numerous studies have examined the effect of psychological variables on surgical recovery, but no definite conclusion has been reached yet. We sought to examine whether psychological factors influence early surgical recovery. METHODS: We performed a systematic search in PubMed, Scopus and PsycINFO databases to identify studies examining the association of preoperative psychological variables or interventions with objectively measured, early surgical outcomes. RESULTS: We identified 16 eligible studies, 15 of which reported a significant association between at least one psychological variable or intervention and an early postoperative outcome. However, most studies also reported psychological factors not influencing surgical recovery and there was significant heterogeneity across the studies. Overall, trait and state anxiety, state anger, active coping, subclinical depression, and intramarital hostility appeared to complicate recovery, while dispositional optimism, religiousness, anger control, low pain expectations, and external locus of control seemed to promote healing. Psychological interventions (guided relaxation, couple support visit, and psychiatric interview also appeared to favor recovery. Psychological factors unrelated to surgical outcomes included loneliness, perceived social support, anger expression, and trait anger. CONCLUSION: Although the heterogeneity of the available evidence precludes any safe conclusions, psychological variables appear to be associated with early surgical recovery; this association could bear important implications for clinical practice. Large clinical trials and further analyses are needed to precisely evaluate the contribution of psychology in surgical recovery.

  11. Precipitation variability assessment of northeast China: Songhua ...

    Indian Academy of Sciences (India)

    Variability in precipitation is critical for the management of water resources. ... applied on precipitation data on a monthly, seasonally, annually, decade scale and the number of rainy ... 2015). As a result, such irregularities in precipitation,. i.e., droughts and floods can affect the ... (January–December), years and decades.

  12. Supersonic propulsion technology. [variable cycle engines

    Science.gov (United States)

    Powers, A. G.; Coltrin, R. E.; Stitt, L. E.; Weber, R. J.; Whitlow, J. B., Jr.

    1979-01-01

    Propulsion concepts for commercial supersonic transports are discussed. It is concluded that variable cycle engines, together with advanced supersonic inlets and low noise coannular nozzles, provide good operating performance for both supersonic and subsonic flight. In addition, they are reasonably quiet during takeoff and landing and have acceptable exhaust emissions.

  13. Graphical route information on variable message signs

    NARCIS (Netherlands)

    Alkim, T.P.; Mede, P.H.J. van der; Janssen, W.H.

    2002-01-01

    Reports on experiments in the Netherlands on the use of graphical route information panels (GRIP) as part of variable message systems (VMS) providing information to drivers. GRIP appear to be as safe as regular VMS. Digestion of the information presented is initially quicker for regular VMS, but

  14. Age dependant somatometric and cephalometric variables among ...

    African Journals Online (AJOL)

    Background: The process of growth passes through stages of developmental processes. This stage is the age. Age is known to affect many parameters in the body and this includes somatometric and cephalometric variables. Methods: The study was conducted with a total number of 409 students of university of Jos, ...

  15. Modeling Coast Redwood Variable Retention Management Regimes

    Science.gov (United States)

    John-Pascal Berrill; Kevin O' Hara

    2007-01-01

    Variable retention is a flexible silvicultural system that provides forest managers with an alternative to clearcutting. While much of the standing volume is removed in one harvesting operation, residual stems are retained to provide structural complexity and wildlife habitat functions, or to accrue volume before removal during subsequent stand entries. The residual...

  16. Quality Assurance in the Presence of Variability

    Science.gov (United States)

    Lauenroth, Kim; Metzger, Andreas; Pohl, Klaus

    Software Product Line Engineering (SPLE) is a reuse-driven development paradigm that has been applied successfully in information system engineering and other domains. Quality assurance of the reusable artifacts of the product line (e.g. requirements, design, and code artifacts) is essential for successful product line engineering. As those artifacts are reused in several products, a defect in a reusable artifact can affect several products of the product line. A central challenge for quality assurance in product line engineering is how to consider product line variability. Since the reusable artifacts contain variability, quality assurance techniques from single-system engineering cannot directly be applied to those artifacts. Therefore, different strategies and techniques have been developed for quality assurance in the presence of variability. In this chapter, we describe those strategies and discuss in more detail one of those strategies, the so called comprehensive strategy. The comprehensive strategy aims at checking the quality of all possible products of the product line and thus offers the highest benefits, since it is able to uncover defects in all possible products of the product line. However, the central challenge for applying the comprehensive strategy is the complexity that results from the product line variability and the large number of potential products of a product line. In this chapter, we present one concrete technique that we have developed to implement the comprehensive strategy that addresses this challenge. The technique is based on model checking technology and allows for a comprehensive verification of domain artifacts against temporal logic properties.

  17. Variability in Labrador Sea Water formation

    NARCIS (Netherlands)

    Gelderloos, R.

    2012-01-01

    The Atlantic Meridional Overturning Circulation (AMOC) transports of a large amount of heat towards the North Atlantic region. Since this circulation is considered to have shown pronounced variability in the past, and a weakening is projected for the 21st century, it is very important to understand

  18. Variable-speed, portable routing skate

    Science.gov (United States)

    Pesch, W. A.

    1967-01-01

    Lightweight, portable, variable-speed routing skate is used on heavy metal subassemblies which are impractical to move to a stationary machine. The assembly, consisting of the housing with rollers, router, and driving mechanism with transmission, weighs about forty pounds. Both speed and depth of cut are adjustable.

  19. Continuous variable tripartite entanglement from twin nonlinearities

    International Nuclear Information System (INIS)

    Olsen, M K; Bradley, A S

    2006-01-01

    In this work, we analyse and compare the continuous variable tripartite entanglement available from the use of two concurrent or cascaded χ (2) nonlinearities. We examine both idealized travelling-wave models and more experimentally realistic intracavity models, showing that tripartite entangled outputs are readily producible. These may be a useful resource for applications such as quantum cryptography and teleportation

  20. Gender as a Macro Economic Variable

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2014-01-01

    markdownabstract__Abstract__ This chapter will analyse how gender can be used in a meaningful way in macroeconomic analysis. The challenge is that gender cannot be measured easily at the macro level. This is either because current gender variables are one-dimensional and miss out much gender

  1. Gender as a Macro Economic Variable

    NARCIS (Netherlands)

    I.P. van Staveren (Irene)

    2013-01-01

    markdownabstract__Abstract__ This chapter will analyse how gender can be used in a meaningful way in macroeconomic analysis. The challenge is that gender cannot be measured easily at the macro level. This is either because current gender variables are one-dimensional and miss out much gender

  2. Non-diffractive optically variable security devices

    NARCIS (Netherlands)

    Renesse, R.L. van

    1991-01-01

    At the past optical security conferences attention was focused on diffractive structures, e.g. holograms, embossed gratings and thin—film devices, as security elements on valuable documents. The main reasons for this emphasis are, that the iridescent effect of such diffractive optically variable

  3. The variable sky of deep synoptic surveys

    Energy Technology Data Exchange (ETDEWEB)

    Ridgway, Stephen T.; Matheson, Thomas; Mighell, Kenneth J.; Olsen, Knut A. [National Optical Astronomy Observatory, Tucson, AZ 85725 (United States); Howell, Steve B., E-mail: ridgway@noao.edu [NASA Ames Research Center, P.O. Box 1, M/S 244-30, Moffett Field, CA 94035 (United States)

    2014-11-20

    The discovery of variable and transient sources is an essential product of synoptic surveys. The alert stream will require filtering for personalized criteria—a process managed by a functionality commonly described as a Broker. In order to understand quantitatively the magnitude of the alert generation and Broker tasks, we have undertaken an analysis of the most numerous types of variable targets in the sky—Galactic stars, quasi-stellar objects (QSOs), active galactic nuclei (AGNs), and asteroids. It is found that the Large Synoptic Survey Telescope (LSST) will be capable of discovering ∼10{sup 5} high latitude (|b| > 20°) variable stars per night at the beginning of the survey. (The corresponding number for |b| < 20° is orders of magnitude larger, but subject to caveats concerning extinction and crowding.) However, the number of new discoveries may well drop below 100 per night within less than one year. The same analysis applied to GAIA clarifies the complementarity of the GAIA and LSST surveys. Discovery of AGNs and QSOs are each predicted to begin at ∼3000 per night and decrease by 50 times over four years. Supernovae are expected at ∼1100 per night, and after several survey years will dominate the new variable discovery rate. LSST asteroid discoveries will start at >10{sup 5} per night, and if orbital determination has a 50% success rate per epoch, they will drop below 1000 per night within two years.

  4. Temporal relationship between climate variability, Prosopis juliflora ...

    African Journals Online (AJOL)

    Normalized Difference Vegetation Index (NDVI) data derived from moderate resolution imaging spectroradiometer (MODIS) 250 m satellite imageries for 2000 to 2014 were used to determine the temporal dynamics of P. juliflora invasion in the study area. Both temperature and rainfall trends showed marked variability over ...

  5. Roles of Variables in Three Programming Paradigms

    Science.gov (United States)

    Sajaniemi, J.; Ben-Ari, M.; Byckling, P.; Gerdt, P.; Kulikova, Y.

    2006-01-01

    Roles can be assigned to occurrences of variables in programs according to a small number of stereotypical patterns of use. Studies on explicitly teaching roles to novices learning programming have shown that roles are an excellent pedagogical tool for clarifying the structure and meaning of programs and that their use improves students'…

  6. Variable Work Hours--The MONY Experience

    Science.gov (United States)

    Fields, Cynthia J.

    1974-01-01

    An experiment with variable work hours in one department of a large company was so successful that it has become standard procedure in various corporate areas, both staff and line. The result? Increased production, fewer errors, improved employee morale, and a significant reduction in lateness and absenteeism. (Author)

  7. Heart rate variability in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Kessing, Lars Vedel; Munkholm, Klaus

    2017-01-01

    Background Heart rate variability (HRV) has been suggested reduced in bipolar disorder (BD) compared with healthy individuals (HC). This meta-analysis investigated: HRV differences in BD compared with HC, major depressive disorder or schizophrenia; HRV differences between affective states; HRV...

  8. Predictability and Variability of Wave and Wind

    DEFF Research Database (Denmark)

    Chozas, Julia Fernandez; Kofoed, Jens Peter; Sørensen, Hans Christian

    This project covers two fields of study: a) Wave energy predictability and electricity markets. b) Variability of the power output of WECs in diversified systems : diversified renewable systems with wave and offshore wind production. See page 2-4 in the report for a executive summery....

  9. The variable sky of deep synoptic surveys

    International Nuclear Information System (INIS)

    Ridgway, Stephen T.; Matheson, Thomas; Mighell, Kenneth J.; Olsen, Knut A.; Howell, Steve B.

    2014-01-01

    The discovery of variable and transient sources is an essential product of synoptic surveys. The alert stream will require filtering for personalized criteria—a process managed by a functionality commonly described as a Broker. In order to understand quantitatively the magnitude of the alert generation and Broker tasks, we have undertaken an analysis of the most numerous types of variable targets in the sky—Galactic stars, quasi-stellar objects (QSOs), active galactic nuclei (AGNs), and asteroids. It is found that the Large Synoptic Survey Telescope (LSST) will be capable of discovering ∼10 5 high latitude (|b| > 20°) variable stars per night at the beginning of the survey. (The corresponding number for |b| < 20° is orders of magnitude larger, but subject to caveats concerning extinction and crowding.) However, the number of new discoveries may well drop below 100 per night within less than one year. The same analysis applied to GAIA clarifies the complementarity of the GAIA and LSST surveys. Discovery of AGNs and QSOs are each predicted to begin at ∼3000 per night and decrease by 50 times over four years. Supernovae are expected at ∼1100 per night, and after several survey years will dominate the new variable discovery rate. LSST asteroid discoveries will start at >10 5 per night, and if orbital determination has a 50% success rate per epoch, they will drop below 1000 per night within two years.

  10. Historic Hydroclimatic Variability in Northern Mexico

    Science.gov (United States)

    José Villanueva-Diaz; J. Cerano-Paredes; D.W. Stahle; B. H. Luckman; M.D. Therrell; M.K. Cleaveland; G. Gutierrez-Garcia

    2006-01-01

    The understanding of historic hydroclimatic variability is basic to plan for a proper management of limited water resources in northern Mexico. The objective of this study was to develop a network of tree-ring chronologies for climate reconstruction and to analyze the influence of circulatory patterns, such as ENSO. Climatic sensitive treering chronologies were...

  11. Political Discourse and Its Sociolinguistic Variables

    Science.gov (United States)

    Reyes-Rodriguez, Antonio

    2008-01-01

    Linguistically, political discourses have generally been discussed within qualitative approaches (e.g., Blackledge, 2005; Chilton, 2004; Chomsky, 2004; van Dijk, 2005; Wodak, 2002). This paper presents tools to design a quantitative research relating political speech with sociolinguistic variables. Notions such as Accommodation Theory (Giles &…

  12. Continuous-variable quantum erasure correcting code

    DEFF Research Database (Denmark)

    Lassen, Mikael Østergaard; Sabuncu, Metin; Huck, Alexander

    2010-01-01

    We experimentally demonstrate a continuous variable quantum erasure-correcting code, which protects coherent states of light against complete erasure. The scheme encodes two coherent states into a bi-party entangled state, and the resulting 4-mode code is conveyed through 4 independent channels...

  13. Infrared variability and nature of symbiotic stars

    Energy Technology Data Exchange (ETDEWEB)

    Feast, M W; Robertson, B S.C.; Catchpole, R M [Royal Observatory, Cape Town (South Africa)

    1977-05-01

    Most symbiotic stars may be placed in one of two classes according to their infrared colours. In one group the systems contain an M type giant. In the other there is evidence for a star plus infrared emission from dust. JHKL photometry is given for three members of each class. Photometry of the VV Cephei system FR Sct is also given. No evidence for variability was found for systems without dust. The three systems with dust (RX Pup, RR Tel and PK 280-2/sup 0/.1) each show large variations of the stellar component (..delta..J, 1sup(m).6 to 2sup(m).7). It is concluded that these dusty systems contain Mira variables. For the systems without dust the mass transfer in the system is presumably through the inner Lagrangian point. For systems containing Miras it is possible that the companion accretes matter from a general stellar wind. Symbiotic systems containing Mira variables have more dust than average Mira variables. Either an unusually dense stellar wind is needed to produce a symbiotic system or such a system produces dust, perhaps in a high-density region resulting from the interaction of the stellar wind with the companion.

  14. Variable speed drives boost air handler benefits

    Energy Technology Data Exchange (ETDEWEB)

    Twenty-four separate roof-top air handlers, controlled by variable speed ac motor drives, provide comfort and ventilation for employees at a 500,000 sq. ft. sportswear distribution center in southern Virginia. They were chosen over optional packaged HVAC units because of their flexibility, efficiency, and short payback advantages. The operation of the units is described.

  15. Gowdy phenomenology in scale-invariant variables

    International Nuclear Information System (INIS)

    Andersson, Lars; Elst, Henk van; Uggla, Claes

    2004-01-01

    The dynamics of Gowdy vacuum spacetimes is considered in terms of Hubble-normalized scale-invariant variables, using the timelike area temporal gauge. The resulting state space formulation provides for a simple mechanism for the formation of 'false' and 'true spikes' in the approach to the singularity, and a geometrical formulation for the local attractor

  16. Travel time variability and airport accessibility

    NARCIS (Netherlands)

    Koster, P.R.; Kroes, E.P.; Verhoef, E.T.

    2011-01-01

    We analyze the cost of access travel time variability for air travelers. Reliable access to airports is important since the cost of missing a flight is likely to be high. First, the determinants of the preferred arrival times at airports are analyzed. Second, the willingness to pay (WTP) for

  17. Aggressive fibromatosis - impact of prognostic variables on ...

    African Journals Online (AJOL)

    Objective. To determine the impact of prognostic variables on local control in patients with aggressive fibromatosis treated with or without radiation. Materials and methods. Forty-two patients presenting to the combined sarcoma clinic at Johannesburg Hospital with aggressive fibromatosis from 1990 to 2003 were analysed ...

  18. Arctic climate change and decadal variability

    NARCIS (Netherlands)

    Linden, van der Eveline C.

    2016-01-01

    High northern latitudes exhibit enhanced near-surface warming in a climate with increasing greenhouse gases compared to other parts of the globe, indicating an amplified climate response to external forcing. Decadal to multidecadal variability sometimes enhances and at other times reduces the

  19. Travel time variability and rational inattention

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Jiang, Gege

    2017-01-01

    This paper sets up a rational inattention model for the choice of departure time for a traveler facing random travel time. The traveler chooses how much information to acquire about the travel time out-come before choosing departure time. This reduces the cost of travel time variability compared...

  20. Relationships and variability of agronomic and physiological ...

    African Journals Online (AJOL)

    This study was conducted to determine the variability, heritability and correlations among agronomic and physiological characters of mungbean (Vigna radiata (L.) Wilczek) and to identify their direct and indirect effects on seed yield. Fifty six mungbean accessions were evaluated at Suranaree University of Technology Farm ...

  1. Entropies, Partitionings and Heart Rate Variability

    Czech Academy of Sciences Publication Activity Database

    Paluš, Milan; Zebrowski, J.

    2009-01-01

    Roč. 51, č. 2 (2009), s. 65-72 ISSN 0001-7604 Institutional research plan: CEZ:AV0Z10300504 Keywords : coarse-grained entropy rate * HR variability * entropy Subject RIV: BB - Applied Statistics, Operational Research http://www.activitas.org/index.php/nervosa/article/view/25

  2. Radio emission from the nova-like variable AC Cancri and the symbiotic variable AG Draconis

    International Nuclear Information System (INIS)

    Torbett, M.V.; Campbell, B.; Mount Wilson and Las Campanas Observatories, Pasadena, CA)

    1987-01-01

    Radio emission at 6 cm has been detected from the nova-like cataclysmic variable AC Cnc and the symbiotic variable AG Dra. The AC Cnc observation constitutes the first radio detection in this class of objects. The AG Dra source is probably resolved and appears to show asymmetric, extended structure. The radio emission can best be explained by thermal bremsstrahlung. 26 references

  3. Variable selection in multivariate calibration based on clustering of variable concept.

    Science.gov (United States)

    Farrokhnia, Maryam; Karimi, Sadegh

    2016-01-01

    Recently we have proposed a new variable selection algorithm, based on clustering of variable concept (CLoVA) in classification problem. With the same idea, this new concept has been applied to a regression problem and then the obtained results have been compared with conventional variable selection strategies for PLS. The basic idea behind the clustering of variable is that, the instrument channels are clustered into different clusters via clustering algorithms. Then, the spectral data of each cluster are subjected to PLS regression. Different real data sets (Cargill corn, Biscuit dough, ACE QSAR, Soy, and Tablet) have been used to evaluate the influence of the clustering of variables on the prediction performances of PLS. Almost in the all cases, the statistical parameter especially in prediction error shows the superiority of CLoVA-PLS respect to other variable selection strategies. Finally the synergy clustering of variable (sCLoVA-PLS), which is used the combination of cluster, has been proposed as an efficient and modification of CLoVA algorithm. The obtained statistical parameter indicates that variable clustering can split useful part from redundant ones, and then based on informative cluster; stable model can be reached. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Examining the Causes of Memory Strength Variability: Recollection, Attention Failure, or Encoding Variability?

    Science.gov (United States)

    Koen, Joshua D.; Aly, Mariam; Wang, Wei-Chun; Yonelinas, Andrew P.

    2013-01-01

    A prominent finding in recognition memory is that studied items are associated with more variability in memory strength than new items. Here, we test 3 competing theories for why this occurs--the "encoding variability," "attention failure", and "recollection" accounts. Distinguishing among these theories is critical…

  5. Improving transition between power optimization and power limitation of variable speed/variable pitch wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A D; Bindner, H [Risoe National Lab., Wind Energy and Atmospheric Physics Dept., Roskilde (Denmark); Rebsdorf, A [Vestas Wind Systems A/S, Lem (Denmark)

    1999-03-01

    The paper summarises and describes the main results of a recently performed study of improving the transition between power optimization and power limitation for variable speed/variable pitch wind turbines. The results show that the capability of varying the generator speed also can be exploited in the transition stage to improve the quality of the generated power. (au)

  6. Focus on variability : New tools to study intra-individual variability in developmental data

    NARCIS (Netherlands)

    van Geert, P; van Dijk, M

    2002-01-01

    In accordance with dynamic systems theory, we assume that variability is an important developmental phenomenon. However, the standard methodological toolkit of the developmental psychologist offers few instruments for the study of variability. In this article we will present several new methods that

  7. Tropical intraseasonal rainfall variability in the CFSR

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiande [I.M. System Group Inc. at NOAA/NCEP/EMC, Camp Springs, MD (United States); Wang, Wanqiu [NOAA/NCEP/CPC, Camp Springs, MD (United States); Fu, Xiouhua [University of Hawaii at Manoa, IPRC, SOEST, Honolulu, HI (United States); Seo, Kyong-Hwan [Pusan National University, Department of Atmospheric Sciences, Busan (Korea, Republic of)

    2012-06-15

    While large-scale circulation fields from atmospheric reanalyses have been widely used to study the tropical intraseasonal variability, rainfall variations from the reanalyses are less focused. Because of the sparseness of in situ observations available in the tropics and strong coupling between convection and large-scale circulation, the accuracy of tropical rainfall from the reanalyses not only measures the quality of reanalysis rainfall but is also to some extent indicative of the accuracy of the circulations fields. This study analyzes tropical intraseasonal rainfall variability in the recently completed NCEP Climate Forecast System Reanalysis (CFSR) and its comparison with the widely used NCEP/NCAR reanalysis (R1) and NCEP/DOE reanalysis (R2). The R1 produces too weak rainfall variability while the R2 generates too strong westward propagation. Compared with the R1 and R2, the CFSR produces greatly improved tropical intraseasonal rainfall variability with the dominance of eastward propagation and more realistic amplitude. An analysis of the relationship between rainfall and large-scale fields using composites based on Madden-Julian Oscillation (MJO) events shows that, in all three NCEP reanalyses, the moisture convergence leading the rainfall maximum is near the surface in the western Pacific but is above 925 hPa in the eastern Indian Ocean. However, the CFSR produces the strongest large-scale convergence and the rainfall from CFSR lags the column integrated precipitable water by 1 or 2 days while R1 and R2 rainfall tends to lead the respective precipitable water. Diabatic heating related to the MJO variability in the CFSR is analyzed and compared with that derived from large-scale fields. It is found that the amplitude of CFSR-produced total heating anomalies is smaller than that of the derived. Rainfall variability from the other two recently produced reanalyses, the ECMWF Re-Analysis Interim (ERAI), and the Modern Era Retrospective-analysis for Research and

  8. El fluoruro en aguas de consumo y su asociación con variables geológicas y geográficas de Cuba

    Directory of Open Access Journals (Sweden)

    Liliam Cuéllar Luna

    2003-11-01

    Full Text Available OBJETIVO: Determinar la asociación entre las diferentes concentraciones del ión fluoruro en aguas de consumo y algunas variables geológicas y geográficas de Cuba, mediante el empleo de un sistema de información geográfica. MÉTODOS: De noviembre de 1998 a octubre de 1999 se estudiaron las concentraciones de fluoruro en fuentes de abastecimiento de agua de consumo de 753 localidades cubanas de 1 000 habitantes o más. Para el análisis de la información se utilizó el sistema de información geográfica MapInfo Professional (v. 5.5 con el método de superposición. Las variables de estudio fueron la concentración del ión fluoruro en fuentes de abastecimiento de agua, las características geológicas del territorio, los alineamientos, los tipos de fuente y las categorías de relieve (llanura o montaña. Los resultados se agruparon por localidad y municipio. RESULTADOS: En 83,1% de las localidades, las muestras de agua fueron recolectadas en pozos y manantiales y en el 16,9% restante, en presas y ríos. De las 753 localidades estudiadas, 675 (89,6% presentaron concentraciones de fluoruro bajas o medias (< 0,7 mg/L. La región oriental del país fue la más afectada por concentraciones elevadas de fluoruro en las aguas, seguida de la región central. La mayoría de las localidades con altas concentraciones de fluoruro natural se localizaron en zonas ubicadas sobre rocas del arco volcánico del Cretácico. La presencia de fluoruro en las aguas de consumo estuvo asociada con los alineamientos de la corteza terrestre, no solo en los complejos rocosos de origen volcánico-sedimentario e intrusivo, sino también en las rocas carbonatadas, aunque se debe destacar que las mayores concentraciones de fluoruro coincidieron fundamentalmente con los dos primeros complejos rocosos mencionados anteriormente. Todas las localidades con concentraciones altas de fluoruro en el agua estaban vinculadas a pozos. CONCLUSIONES: La concentración de fluoruro en

  9. Climate Variability and Sugarcane Yield in Louisiana.

    Science.gov (United States)

    Greenland, David

    2005-11-01

    This paper seeks to understand the role that climate variability has on annual yield of sugarcane in Louisiana. Unique features of sugarcane growth in Louisiana and nonclimatic, yield-influencing factors make this goal an interesting and challenging one. Several methods of seeking and establishing the relations between yield and climate variables are employed. First, yield climate relations were investigated at a single research station where crop variety and growing conditions could be held constant and yield relations could be established between a predominant older crop variety and a newer one. Interviews with crop experts and a literature survey were used to identify potential climatic factors that control yield. A statistical analysis was performed using statewide yield data from the American Sugar Cane League from 1963 to 2002 and a climate database. Yield values for later years were adjusted downward to form an adjusted yield dataset. The climate database was principally constructed from daily and monthly values of maximum and minimum temperature and daily and monthly total precipitation for six cooperative weather-reporting stations representative of the area of sugarcane production. The influence of 74 different, though not independent, climate-related variables on sugarcane yield was investigated. The fact that a climate signal exists is demonstrated by comparing mean values of the climate variables corresponding to the upper and lower third of adjusted yield values. Most of these mean-value differences show an intuitively plausible difference between the high- and low-yield years. The difference between means of the climate variables for years corresponding to the upper and lower third of annual yield values for 13 of the variables is statistically significant at or above the 90% level. A correlation matrix was used to identify the variables that had the largest influence on annual yield. Four variables [called here critical climatic variables (CCV

  10. Cryotherapy, Sensation, and Isometric-Force Variability

    Science.gov (United States)

    Denegar, Craig R.; Buckley, William E.; Newell, Karl M.

    2003-01-01

    Objective: To determine the changes in sensation of pressure, 2-point discrimination, and submaximal isometric-force production variability due to cryotherapy. Design and Setting: Sensation was assessed using a 2 × 2 × 2 × 3 repeated-measures factorial design, with treatment (ice immersion or control), limb (right or left), digit (finger or thumb), and sensation test time (baseline, posttreatment, or postisometric-force trials) as independent variables. Dependent variables were changes in sensation of pressure and 2-point discrimination. Isometric-force variability was tested with a 2 × 2 × 3 repeated-measures factorial design. Treatment condition (ice immersion or control), limb (right or left), and percentage (10, 25, or 40) of maximal voluntary isometric contraction (MVIC) were the independent variables. The dependent variables were the precision or variability (the standard deviation of mean isometric force) and the accuracy or targeting error (the root mean square error) of the isometric force for each percentage of MVIC. Subjects: Fifteen volunteer college students (8 men, 7 women; age = 22 ± 3 years; mass = 72 ± 21.9 kg; height = 183.4 ± 11.6 cm). Measurements: We measured sensation in the distal palmar aspect of the index finger and thumb. Sensation of pressure and 2-point discrimination were measured before treatment (baseline), after treatment (15 minutes of ice immersion or control), and at the completion of isometric testing (final). Variability (standard deviation of mean isometric force) of the submaximal isometric finger forces was measured by having the subjects exert a pinching force with the thumb and index finger for 30 seconds. Subjects performed the pinching task at the 3 submaximal levels of MVIC (10%, 25%, and 40%), with the order of trials assigned randomly. The subjects were given a target representing the submaximal percentage of MVIC and visual feedback of the force produced as they pinched the testing device. The force exerted

  11. Seasonal Variability in European Radon Measurements

    Science.gov (United States)

    Groves-Kirkby, C. J.; Denman, A. R.; Phillips, P. S.; Crockett, R. G. M.; Sinclair, J. M.

    2009-04-01

    In temperate climates, domestic radon concentration levels are generally seasonally dependent, the level in the home reflecting the convolution of two time-dependent functions. These are the source soil-gas radon concentration itself, and the principal force driving radon into the building from the soil, namely the pressure-difference between interior and exterior environment. While the meteorological influence can be regarded as relatively uniform on a European scale, its variability being defined largely by the influence of North-Atlantic weather systems, soil-gas radon is generally more variable as it is essentially geologically dependent. Seasonal variability of domestic radon concentration can therefore be expected to exhibit geographical variability, as is indeed the case. To compensate for the variability of domestic radon levels when assessing the long term radon health risks, the results of individual short-term measurements are generally converted to equivalent mean annual levels by application of a Seasonal Correction Factor (SCF). This is a multiplying factor, typically derived from measurements of a large number of homes, applied to the measured short-term radon concentration to provide a meaningful annual mean concentration for dose-estimation purposes. Following concern as to the universal applicability of a single SCF set, detailed studies in both the UK and France have reported location-specific SCF sets for different regions of each country. Further results indicate that SCFs applicable to the UK differ significantly from those applicable elsewhere in Europe and North America in both amplitude and phase, supporting the thesis that seasonal variability in indoor radon concentration cannot realistically be compensated for by a single national or international SCF scheme. Published data characterising the seasonal variability of European national domestic radon concentrations, has been collated and analysed, with the objective of identifying

  12. Gait variability measurements in lumbar spinal stenosis patients: part B. Preoperative versus postoperative gait variability

    International Nuclear Information System (INIS)

    Papadakis, N C; Christakis, D G; Tzagarakis, G N; Chlouverakis, G I; Kampanis, N A; Stergiopoulos, K N; Katonis, P G

    2009-01-01

    The objective of this study was to assess the gait variability of lumbar spinal stenosis (LSS) patients and to evaluate its postoperative progression. The hypothesis was that LSS patients' preoperative gait variability in the frequency domain was higher than the corresponding postoperative. A tri-axial accelerometer sensor was used for the gait measurement and a spectral differential entropy algorithm was used to measure the gait variability. Twelve subjects with LSS were measured before and after surgery. Preoperative measurements were performed 2 days before surgery. Postoperative measurements were performed 6 and 12 months after surgery. Preoperative gait variability was higher than the corresponding postoperative. Also, in most cases, gait variability appeared to decrease throughout the year

  13. Searching for nova shells around cataclysmic variables

    Science.gov (United States)

    Sahman, D. I.; Dhillon, V. S.; Knigge, C.; Marsh, T. R.

    2015-08-01

    We present the results of a search for nova shells around 101 cataclysmic variables (CVs), using H α images taken with the 4.2-m William Herschel Telescope (WHT) and the 2.5-m Isaac Newton Telescope Photometric H α Survey of the Northern Galactic Plane (IPHAS). Both telescopes are located on La Palma. We concentrated our WHT search on nova-like variables, whilst our IPHAS search covered all CVs in the IPHAS footprint. We found one shell out of the 24 nova-like variables we examined. The newly discovered shell is around V1315 Aql and has a radius of ˜2.5 arcmin, indicative of a nova eruption approximately 120 yr ago. This result is consistent with the idea that the high mass-transfer rate exhibited by nova-like variables is due to enhanced irradiation of the secondary by the hot white dwarf following a recent nova eruption. The implications of our observations for the lifetime of the nova-like variable phase are discussed. We also examined four asynchronous polars, but found no new shells around any of them, so we are unable to confirm that a recent nova eruption is the cause of the asynchronicity in the white dwarf spin. We find tentative evidence of a faint shell around the dwarf nova V1363 Cyg. In addition, we find evidence for a light echo around the nova V2275 Cyg, which erupted in 2001, indicative of an earlier nova eruption ˜300 yr ago, making V2275 Cyg a possible recurrent nova.

  14. Extreme Variables in Star Forming Regions

    Science.gov (United States)

    Contreras Peña, Carlos Eduardo

    2015-01-01

    The notion that low- to intermediate-mass young stellar objects (YSOs) gain mass at a constant rate during the early stages of their evolution appears to be challenged by observations of YSOs suffering sudden increases of the rate at which they gain mass from their circumstellar discs. Also, this idea that stars spend most of their lifetime with a low accretion rate and gain most of their final mass during short-lived episodes of high accretion bursts, helps to solve some long-standing problems in stellar evolution. The original classification of eruptive variables divides them in two separate subclasses known as FU Orionis stars (FUors) and EX Lupi stars (EXors). In this classical view FUors are at an early evolutionary stage and are still gaining mass from their parent envelopes, whilst EXors are thought to be older objects only surrounded by an accretion disc. The problem with this classical view is that it excludes younger protostars which have higher accretion rates but are too deeply embedded in circumstellar matter to be observed at optical wavelengths. Optically invisible protostars have been observed to display large variability in the near-infrared. These and some recent discoveries of new eruptive variables, show characteristics that can be attributed to both of the optically-defined subclasses of eruptive variables. The new objects have been proposed to be part of a new class of eruptive variables. However, a more accepted scenario is that in fact the original classes only represent two extremes of the same phenomena. In this sense eruptive variability could be explained as arising from one physical mechanism, i.e. unsteady accretion, where a variation in the parameters of such mechanism can cause the different characteristics observed in the members of this class. With the aim of studying the incidence of episodic accretion among young stellar objects, and to characterize the nature of these eruptive variables we searched for high amplitude variability

  15. CHARACTERIZING THE OPTICAL VARIABILITY OF BRIGHT BLAZARS: VARIABILITY-BASED SELECTION OF FERMI ACTIVE GALACTIC NUCLEI

    International Nuclear Information System (INIS)

    Ruan, John J.; Anderson, Scott F.; MacLeod, Chelsea L.; Becker, Andrew C.; Davenport, James R. A.; Ivezić, Željko; Burnett, T. H.; Kochanek, Christopher S.; Plotkin, Richard M.; Sesar, Branimir; Stuart, J. Scott

    2012-01-01

    We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the ∼30% of γ-ray sources in the Fermi 2FGL catalog still lacking reliable associations. Using data from the optical LINEAR asteroid survey, we characterize the optical variability of blazars by fitting a damped random walk model to individual light curves with two main model parameters, the characteristic timescales of variability τ, and driving amplitudes on short timescales σ-circumflex. Imposing cuts on minimum τ and σ-circumflex allows for blazar selection with high efficiency E and completeness C. To test the efficacy of this approach, we apply this method to optically variable LINEAR objects that fall within the several-arcminute error ellipses of γ-ray sources in the Fermi 2FGL catalog. Despite the extreme stellar contamination at the shallow depth of the LINEAR survey, we are able to recover previously associated optical counterparts to Fermi active galactic nuclei with E ≥ 88% and C = 88% in Fermi 95% confidence error ellipses having semimajor axis r < 8'. We find that the suggested radio counterpart to Fermi source 2FGL J1649.6+5238 has optical variability consistent with other γ-ray blazars and is likely to be the γ-ray source. Our results suggest that the variability of the non-thermal jet emission in blazars is stochastic in nature, with unique variability properties due to the effects of relativistic beaming. After correcting for beaming, we estimate that the characteristic timescale of blazar variability is ∼3 years in the rest frame of the jet, in contrast with the ∼320 day disk flux timescale observed in quasars. The variability-based selection method presented will be useful for blazar identification in time-domain optical surveys and is also a probe of jet physics.

  16. Dynamically variable spot size laser system

    Science.gov (United States)

    Gradl, Paul R. (Inventor); Hurst, John F. (Inventor); Middleton, James R. (Inventor)

    2012-01-01

    A Dynamically Variable Spot Size (DVSS) laser system for bonding metal components includes an elongated housing containing a light entry aperture coupled to a laser beam transmission cable and a light exit aperture. A plurality of lenses contained within the housing focus a laser beam from the light entry aperture through the light exit aperture. The lenses may be dynamically adjusted to vary the spot size of the laser. A plurality of interoperable safety devices, including a manually depressible interlock switch, an internal proximity sensor, a remotely operated potentiometer, a remotely activated toggle and a power supply interlock, prevent activation of the laser and DVSS laser system if each safety device does not provide a closed circuit. The remotely operated potentiometer also provides continuous variability in laser energy output.

  17. The variability problem of normal human walking

    DEFF Research Database (Denmark)

    Simonsen, Erik B; Alkjær, Tine

    2012-01-01

    Previous investigations have suggested considerable inter-individual variability in the time course pattern of net joint moments during normal human walking, although the limited sample sizes precluded statistical analyses. The purpose of the present study was to obtain joint moment patterns from...... a group of normal subjects and to test whether or not the expected differences would prove to be statistically significant. Fifteen healthy male subjects were recorded on video while they walked across two force platforms. Ten kinematic and kinetic parameters were selected and input to a statistical...... cluster analysis to determine whether or not the 15 subjects could be divided into different 'families' (clusters) of walking strategy. The net joint moments showed a variability corroborating earlier reports. The cluster analysis showed that the 15 subjects could be grouped into two clusters of 5 and 10...

  18. Maximal Inequalities for Dependent Random Variables

    DEFF Research Database (Denmark)

    Hoffmann-Jorgensen, Jorgen

    2016-01-01

    Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X-k. Then a......Maximal inequalities play a crucial role in many probabilistic limit theorem; for instance, the law of large numbers, the law of the iterated logarithm, the martingale limit theorem and the central limit theorem. Let X-1, X-2,... be random variables with partial sums S-k = X-1 + ... + X......-k. Then a maximal inequality gives conditions ensuring that the maximal partial sum M-n = max(1) (...

  19. Quantum walk with one variable absorbing boundary

    International Nuclear Information System (INIS)

    Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli

    2017-01-01

    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks. - Highlights: • A novel scheme about quantum walk with variable boundary is proposed. • The analytical results of the survival probability from the absorbing boundary. • The behavior of survival probability under different boundary conditions. • The influence of different initial coin states on the survival probability.

  20. Intraseasonal variability and tides in Makassar Strait

    Science.gov (United States)

    Susanto, R. Dwi; Gordon, Arnold L.; Sprintall, Janet; Herunadi, Bambang

    2000-05-01

    Intraseasonal variability and tides along the Makassar Strait, the major route of Indonesian throughflow, are investigated using spectral and time-frequency analyses which are applied to sea level, wind and mooring data. Semidiurnal and diurnal tides are dominant features, with higher (lower) semidiurnal (diurnal) energy in the north compared to the south. Sea levels and mooring data display intraseasonal variability which are probably a response to remotely forced Kelvin waves from the Indian Ocean through Lombok Strait and to Rossby waves from the Pacific Ocean. Sea levels in Tarakan and Balikpapan and Makassar mooring velocities reveal intraseasonal features with periods of 48-62 days associated with Rossby waves from the Sulawesi Sea. Kelvin wave features with periods of 67-100 days are seen in Bali (Lombok Strait), at the mooring sites and in Balikpapan, however, they are not seen in Tarakan, which implies that these waves diminish after passing through the Makassar Strait.