WorldWideScience

Sample records for arbustiva del monte

  1. Variación del espesor cuticular foliar de cinco especies arbustivas del sur del Caldenal, Provincia de La Pampa, Argentina

    OpenAIRE

    Peláez, Daniel V.; Bóo, R. M.; Elía, O. R.

    1985-01-01

    p.177-182 Debido a la importancia que asume el espesor de la membrana cuticular en la penetración foliar de los herbicidas, el objetivo del presente trabajo fue estudiar la variación de la misma en Prosopis caldenia, Prosopis flexuosa, Larrea divaricata, Condalia microphylla y Chuquiraga erinacea, cinco de las especies arbustivas invasoras más conspicuas de la zona semiárida templada, en tres momentos distintos durante el transcurso de sus respectivos ciclos anuales de crecimiento. Se obse...

  2. Uso de las leguminosas arbustivas en los sistemas de producción animal en el trópico

    OpenAIRE

    Jaime Olivares Pérez; Saúl Rojas Hernández;; Régulo Jiménez Guillén; Pedro Arturo Martínez Hernández.

    2005-01-01

    Este trabajo es una revisión bibliográfica del como podrían utilizarse las leguminosas arbustivas como un recurso natural en los sistemas de producción animal, con reportes del impacto en el recurso suelo, animal y de manera general en el medio ambiente, donde se han introducido estas especies vegetales.

  3. Patrones de distribución de especies arbustivas respecto a arbóreas a lo largo de un gradiente ambiental atlántico-mediterráneo: una aproximación a partir de datos del tercer Inventario Forestal Nacional

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    A. E. Olthoff

    2016-01-01

    Full Text Available Los inventarios forestales nacionales representan una fuente de datos de gran interés teórico y para la gestión. Sin embargo, su uso como herramienta para la caracterización del nicho de las especies arbóreas y arbustivas ha sido limitado. En este trabajo, se utilizan datos del tercer Inventario Forestal Nacional (IFN3 en la provincia de Palencia, para describir los patrones de distribución y las propiedades del nicho efectivo de las principales especies forestales (árboles y arbustos, a lo largo del gradiente ambiental atlántico-mediterráneo típico del norte de España. El principal gradiente de comunidades (coenoclina identificado se relaciona con las diferencias climáticas norte-sur, mientras que el segundo muestra un recambio en la composición florística de los bosques en relación con la pendiente. Las curvas de respuesta unimodal son las más frecuentes, lo que sugiere un considerable recambio en la composición florística de los bosques a lo largo del gradiente norte-sur. Los nichos de las especies con características similares están más próximos, son más amplios para las especies que ocupan ambientes con fuerte contraste o transicionales y más estrechos para las que ocupan hábitats muy particulares. La metodología utilizada basada en datos del Inventario Forestal Nacional proporciona una evaluación objetiva de la forma de respuestas de las especies a lo largo de gradientes ecológicos complejos.

  4. Las obras de acondicionamiento del Salto del Mont-Cenis

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    Vié, Georges

    1969-06-01

    Full Text Available The new dam at Mont Cenis has increased to water volume in the reservoir from 32 to 320 million m3 and provides a potential energy of 650.000 million Mp x m. This article describes the work involved in the construction of this project. Among other features, the water has been led to the reservoir along a network of varying cross-section, and of 28 km total length. The pressure conduit has been designed for a flow rate of 51 m3/s, its diameter varying between 4 and 5 m. The new power stations at Villarodin are fed by a pipe 3.6 km in length and 3 m in diameter. This conduit runs along a trench and is isolated from the ground, because of the gypsum and anhydrites contained in the soil. Its weight is 10.000 Mp, which is a European record. The power station comprises to vertical Pelton turbines of 195 MVA each, and a yearly output of 485 kWh.La capacidad de la nueva presa del Mont-Cenis ha aumentado con estas obras desde 32 hasta 320 millones de m3, permitiendo el abastecimiento de una energía potencial de 650.000 millones de Mp x m. En el artículo se describen las obras y operaciones necesarias para ello; entre otras, que las aguas captadas han sido llevadas al embalse por una red de galerías de sección variable de 28 km de longitud; y que la conducción forzada, de 18 km de longitud, fue dimensionada para un caudal de 51 m3/s, con un diámetro comprendido entre 4 y 5 metros. Las nuevas centrales de Villarodin están alimentadas por una desviación de 3,6 km de longitud y 3 m de diámetro. Este conducto, colocado en un foso inclinado para aislarlo del ter reno, en esa zona de yesos y anhidritas, principalmente, tiene un peso de 10.000 Mp, lo que constituye un récord europeo. La Central comprende dos grupos verticales de turbinas Pelton de 195 MVA cada uno, con una productividad de 485 millones de kWh.

  5. en el desierto del Monte, Argentina

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    C.M. Campos

    2015-01-01

    Full Text Available Los bosques de Prosopis flexuosa proporcionan múltiples bienes y servicios. Actualmente, sufren una fuerte retracción debido a un uso histórico extractivistay se hace necesario promover la conservación y el manejo sostenible de los bosques como sistema. El objetivo del trabajo es sintetizarel conocimiento disponible acerca de las interacciones mutualistas y antagonistas entre mamíferos, frutos y semillas de P. flexuosa, comparandocon estudios realizados en otras especies de Prosopis de Argentina. Se considera a dos grupos de consumidores oportunistas de frutos: almacenadoresen cúmulos dispersos y frugívoros. Los roedores pequeños (como Eligmodontia typus y Microcavia australis son dispersores de semillasporque depredan pocas semillas y almacenan el resto en cúmulos sobre la superficie del suelo. Mamíferos frugívoros oportunistas silvestres (Dolichotispatagonum, Lepus europaeus, Lycalopex griseus, Lama guanicoe, etc. y domésticos (burro, caballo, vaca son dispersores endozoocóricosy proporcionan beneficios como el traslado de grandes cantidades de semillas, la eliminación de estructuras que mantienen la dormición y la desinfecciónde semillas atacadas por insectos. Sin embargo, la endozoocoria tiene costos sobre la viabilidad y la capacidad germinativa de las semillas.Ante un panorama de continuos cambios en el uso de la tierra y de cambio climático global, el conocimiento acerca del espectro diverso de animalesque proporcionan el beneficio de dispersión de semillas aporta bases científicas para considerar que la biodiversidad asociada a los bosques debeincluirse en la gestión y conservación de los mismos.

  6. La sauna de la Segunda Edad del Hierro del oppidum de Monte Ornedo (Cantabria, España

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    FERNÁNDEZ VEGA, P.A., MANTECÓN CALLEJO, L., CALLEJO GÓMEZ, J., BOLADO DEL CASTILLO, R.

    2014-01-01

    Full Text Available En el presente artículo se presenta los resultados de la excavación del Sondeo 3 del yacimiento prerromano de Monte Ornedo (Valdeolea, Cantabria, una estructura cuya compartimentación y funcionalidad parecen relacionarla con una sauna.

  7. Plan de marketing de un destino turístico: Zarzuela del Monte

    OpenAIRE

    Bermejo de la Puente, Raquel

    2015-01-01

    La finalidad de este proyecto es realizar, ayudándome de las herramientas del marketing, un estudio exhaustivo del municipio segoviano de Zarzuela del Monte, es decir, una auténtica radiografía del mismo, para que futuros inversores tengan una base en qué apoyar sus ideas en lo que a posibilidades turísticas se refiere. En este plan analizaremos los recursos y capacidades que el municipio tiene en la actualidad para satisfacer las necesidades del visitante, así como una valoración del turismo...

  8. Use of Monte Carlo Methods in brachytherapy; Uso del metodo de Monte Carlo en braquiterapia

    Energy Technology Data Exchange (ETDEWEB)

    Granero Cabanero, D.

    2015-07-01

    The Monte Carlo method has become a fundamental tool for brachytherapy dosimetry mainly because no difficulties associated with experimental dosimetry. In brachytherapy the main handicap of experimental dosimetry is the high dose gradient near the present sources making small uncertainties in the positioning of the detectors lead to large uncertainties in the dose. This presentation will review mainly the procedure for calculating dose distributions around a fountain using the Monte Carlo method showing the difficulties inherent in these calculations. In addition we will briefly review other applications of the method of Monte Carlo in brachytherapy dosimetry, as its use in advanced calculation algorithms, calculating barriers or obtaining dose applicators around. (Author)

  9. El peso del conejo de monte criado en jaula

    OpenAIRE

    P. González-Redondo

    1997-01-01

    Live weights of 19 wild rabbits (Orycrolagus cuniculus) reared in cages were measured and compared to the expected weights according to the growth curve followed by the wild rabbits growing in a natural environment. The results obtained, show that the rearing in captivity does not produces an increase in live weight of the wil rabbit. Los pesos de 19 conejos de monte (Orycrolagus cuniculus) criados en jaula fueron medidos y comparados con los pesos esperados segun una curva de crecimiento ...

  10. Asistencia Geriátrica Especializada. Experiencia del Hospital Monte Naranco

    OpenAIRE

    Bruno, Julio

    2016-01-01

    Libro resumen de las ponencias presentadas a las Jornadas de carácter nacional. de 1407 paginas. Editado por el INSALUD Capitulo dedicado a las NUEVAS ALTERNATIVAS DE GESTION DE RECURSOS que recoge la pOnencia: Asistencia Geriatrica Especializada "Experiencia del Hospital Monte Naranco" pags 1060-1079 Analysis of the organizational efficiency of geriatric care service in a Health Area of the Principality of Asturias. Cooperation between tertiary hospitals and geriatric care centers spec...

  11. Micromammiferi del Parco Regionale di Monte Cucco (Perugia

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    A.M. Paci

    2003-10-01

    Full Text Available Il M.te Cucco, situato sull?Appennino umbro-marchigiano settentrionale ma compreso interamente nella provincia di Perugia, per le sue peculiarità naturalistiche è stato dichiarato nel 1995 Parco Naturale Regionale (L.R. 9/95. Molti sono i lavori di valenza scientifica o divulgativa sulle emergenze geo-paleontologiche, floristiche, entomologiche e paesaggistiche di questo massiccio. Da alcuni anni si conducono ricerche ornitologiche e teriologiche, ma per i micromammiferi mancano ancora indagini mirate. Il contributo cerca di fare un primo punto sulla ricchezza della microteriofauna dell?intero ambito protetto e di fornire, al contempo, nuovi dati sulla posizione zoogeografica di alcune specie. La raccolta di informazioni si è rivolta unicamente all?annotazione di vari elementi di presenza (da avvistamento diretto, boli, carcasse, tane, resti di pasto, bibliografia a partire dall?anno 2000. I dati collezionati hanno accertato: 1 Erinaceus europaeus; 2 Sorex minutus; 3 S. samniticus; 4 Crocidura leucodon; 5 C. suaveolens; 6 Suncus etruscus; 7 T. caeca; 8 Talpa europaea; 9 Sciurus vulgaris; 10 Clethrionomys glareolus; 11 Microtus savii; 12 A. flavicollis; 13 Apodemus sylvaticus; 14 Rattus norvegicus; 15 Mus domesticus; 16 Glis glis; 17 Muscardinus avellanarius; 18 Eliomys quercinus. Interessante la presenza di quasi tutti gli Insectivora del centro Italia, alcuni dei quali a diffusione regionale poco conosciuta quali Sorex minutus e Talpa caeca. Quest?ultima, per ecologia e rarità, può essere considerata tra gli elementi faunistici qualificanti la natura dello stesso Parco nel quale, oltre i 1000 m. s.l.m., è risultata in parapatria con Talpa europaea. Anche qui, come in altre località della provincia di Perugia, sono stati trovati crani di

  12. Herpetofauna del Parque Nacional de Monte Alén (Río Muni, Guinea Ecuatorial

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    Lasso, C. A.

    2002-12-01

    Full Text Available In the framework of a broad study of the vertebrate diversity at Monte Alen National Park (Río Muni, Equatorial Guinea, we identified 16 families, 47 genera, and 65 species of reptiles and seven families, 29 genera, and 56 species of amphibians. 21 species of reptiles and four species of amphibians represent new records for the Río Muni region. We present the preliminary inventory of the herpetofauna as well as some ecological comments. Monte Alén is considered one of the most diverse protected areas in central Africa from a herpetological standpoint.

    En el marco de un estudio general sobre de la diversidad de vertebrados del Parque Nacional de Monte Alén (Río Muni, Guinea Ecuatorial, se identificaron 16 familias, 47 géneros y 65 especies de reptiles, y 7 familias, 29 géneros y 56 especies de anfibios; 21 especies de reptiles y 4 de anfibios representan nuevos registros para la región de Río Muni. En el presente trabajo se expone el inventario preliminar de especies e información ecológica puntual sobre las mismas. Monte Alén puede ser considerada una de las áreas protegidas de mayor diversidad herpetológica de África central.

  13. El polen de las mieles del valle de Río Negro, provincia fitogeográfica del monte (Argentina

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    María C. Tellería

    2000-01-01

    Full Text Available Tellería, M. C. & Forcone, A. 2000. El polen de las mieles del valle de Río Negro, provinciafitogeográfica del monte (Argentina. Darwiniana 38(3-4: 273-277.Se realizó el análisis palinológico de 41 muestras de miel del valle de Río Negro. El contenido polínicode las muestras fue acetolizado e identificado por comparación con una colección de polen de referencia.Del total de muestras examinadas, 26 fueron mixtas y las restantes monoflorales de: Tamarix gallica (8muestras, Eucalyptus sp. (2 muestras, Melilotus sp. (1 muestra, Centaurea sp. (1 muestra, Prosopissp. (1 muestra, Brassicaceae (1 muestra y Monttea aphylla (1 muestra. Estas mieles pueden diferenciar-se de aquellas que se producen en el valle inferior del río Chubut, en la misma región fitogeográfica

  14. Plan técnico de gestión forestal del monte nº 46 del C.U.P. "La Jurisdicción"

    OpenAIRE

    Parra Jiménez, Cynthia María

    2013-01-01

    En el presente Trabajo Fin de Máster se ha procedido a la realización de un plan técnico de gestión del monte nº46 del Catálogo de Utilidad Pública llamado “La Jurisdicción” siguiendo las Instrucciones de Ordenación de Montes de la Comunidad de Madrid mediante el método de ordenación por rodales. El monte está situado en San Lorenzo de El Escorial (Madrid). La masa procede de una repoblación llevada a cabo a finales del siglo XIX y principios del siglo XX. Se trata de una masa mixta en la que...

  15. Notas sobre la organización y ubicación del arte paleolítico en las cuevas del monte del Castillo (Puente Viesgo. Santander

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    Reynaldo GONZÁLEZ GARCÍA

    2009-10-01

    Full Text Available El presente artículo es un pequeño resumen de una parte de las conclusiones de los trabajos realizados en el transcurso del verano de 1985 en el Monte del Castillo. El propósito de los mismos se orientó en una total y exhaustiva revisión de la gran mayoría de figuras paleolíticas, tanto pintadas, grabadas, y en algún caso esculpidas, de las cuatro cuevas que forman este prestigioso y conocido conjunto troglodítico: La cueva de las Monedas, la cueva de la Pasiega, la cueva de las Chimeneas y la cueva del Castillo, en Puente Viesgo, Santander.

  16. Los montes y su desamortización en los pueblos del sur del valle de Toluca (México), 1880-1917

    OpenAIRE

    Cesar Fernando Escudero Martínez; Gloria Camacho Pichardo

    2015-01-01

    Este artículo pretende aproximarse al estudio de la desamortización de los montes en los pueblos del sur del valle de Toluca (1880-1917). Llama la atención al análisis de la explotación de la madera en beneficio de la industria, para establecer las diversas respuestas y medidas que adoptaron tanto los pueblos en cuestión, sus ayuntamientos y el gobierno estatal frente al fraccionamiento de la propiedad comunal de los montes, en el contexto de modernización económica e industrial que vivió el ...

  17. 77 FR 4897 - Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James River, Isle of Wight, VA

    Science.gov (United States)

    2012-02-01

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James... live-fire gun exercises on the M/V Del Monte. This action is intended to restrict vessel traffic movement to protect mariners from the hazards associated with the live-fire gun exercise. DATES: This...

  18. 76 FR 31848 - Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James River, Isle of Wight, Virginia

    Science.gov (United States)

    2011-06-02

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James... the live-fire gun exercises on the M/V Del Monte. This action is intended to restrict vessel traffic movement to protect mariners from the hazards associated with the live-fire gun exercise. DATES: This...

  19. VARIACIÓN DEL CONTENIDO DE TANINOS EN PLANTAS DEL MONTE GALLEGO

    OpenAIRE

    González-Hernández, M. P.; Starkey, E. E.; Karchesy, J.

    2011-01-01

    Los taninos son compuestos fenólicos de importancia en las relaciones herbívoroplanta, ya que pueden reducir la digestibilidad de la vegetación y actuar como sustancias repelentes debido a su característico sabor astringente y a veces toxicidad. En muchas ocasiones, pueden formar complejos insolubles con las proteínas que son excretados a través de las heces, de este modo disminuyendo la cantidad de proteína digestible en el alimento. Se estudió la variación estacional del contenido de tanino...

  20. 75 FR 44720 - Safety Zone; Live-Fire Gun Exercise, M/V Del Monte, James River, VA

    Science.gov (United States)

    2010-07-29

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Live-Fire Gun Exercise, M/V Del Monte... specified waters of the James River to protect mariners from the hazards associated with live fire and... use of weapons. This training is necessary to ensure that Navy personnel located within the...

  1. Los montes y su desamortización en los pueblos del sur del valle de Toluca (México, 1880-1917

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    Cesar Fernando Escudero Martínez

    2015-01-01

    Full Text Available Este artículo pretende aproximarse al estudio de la desamortización de los montes en los pueblos del sur del valle de Toluca (1880-1917. Llama la atención al análisis de la explotación de la madera en beneficio de la industria, para establecer las diversas respuestas y medidas que adoptaron tanto los pueblos en cuestión, sus ayuntamientos y el gobierno estatal frente al fraccionamiento de la propiedad comunal de los montes, en el contexto de modernización económica e industrial que vivió el país. Si bien es cierto, la explotación de los montes y sus recursos respondió a una demanda externa, ésta propició que se alteraran las relaciones entre los habitantes y las autoridades por la extracción de recursos, especialmente porque la llegada de nuevos actores puso de manifiesto la importancia económica que había tomado el recurso forestal y los derivados que podían tomarse del monte, lo cual puede ser considerado como una señal del replanteamiento de los recursos en el contexto ya mencionado.

  2. Los montes y su desamortización en los pueblos del sur del valle de Toluca (México, 1880-1917

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    Cesar Fernando Escudero Martínez

    2015-02-01

    Full Text Available Este artículo pretende aproximarse al estudio de la desamortización de los montes en los pueblos del sur del valle de Toluca (1880-1917. Llama la atención al análisis de la explotación de la madera en beneficio de la industria, para establecer las diversas respuestas y medidas que adoptaron tanto los pueblos en cuestión, sus ayuntamientos y el gobierno estatal frente al fraccionamiento de la propiedad comunal de los montes, en el contexto de modernización económica e industrial que vivió el país. Si bien es cierto, la explotación de los montes y sus recursos respondió a una demanda externa, ésta propició que se alteraran las relaciones entre los habitantes y las autoridades por la extracción de recursos, especialmente porque la llegada de nuevos actores puso de manifiesto la importancia económica que había tomado el recurso forestal y los derivados que podían tomarse del monte, lo cual puede ser considerado como una señal del replanteamiento de los recursos en el contexto ya mencionado.

  3. Valores y pautas de crianza familiar en los montes del Pas

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    Petra María PÉREZ ALONSO-GETA

    2009-11-01

    Full Text Available RESUMEN: La comunidad asentada en los montes del Pas es una sociedad que se define como agrícola, rural y campesina. La familia es a la vez unidad doméstica y productiva, ocupada básicamente en labores agrarias y ganaderas.El objetivo final de este estudio es el conocimiento de las pautas de crianza y transmisión cultural del pueblo pasiego. Tratamos de conocer mejor el mundo de la educación familiar para desde ese conocimiento avanzar adecuadamente en la toma de decisiones pedagógicas. Por los datos recogidos cabe hablar de la existencia de unas relaciones intergeneracionales cálidas y positivas, donde la atención, cooperación y solidaridad son un hecho. La familia comparte espacios, tiempos y tareas. Los niños aprenden a través del modelado los valores, normas y pautas de conducta. Enseñan a los niños a tener palabra, ser trabajadores y respetuosos. Los niños van al campo desde muy pequeños a ayudar. Trabajan mucho. Los valores que definen son la laboriosidad, el esfuerzo para el progreso económico, lealtad, tener palabra y solidaridad. Se ayudan mucho entre ellos.ABSTRACT: The community settled in the mountains of the Pas is a society which is described as agricultural and rural. The family is both the domestic and productive unit, basically working in farming and stockbreeding tasks.The final aim of this estudy is to know the nurturing and cultural transmission guidelines of the pasiego people. We aim to know the world of the education within the family better and, from this knowledge, to advance appropriately in the educational decission making. From the gathered data we may assume that there are warm and positive intergenerational relationships, where care, cooperation and solidarity are real. The familiy share spaces, time and tasks; children learn through the modeling of valúes, norms and guidelines. They are taught to have their own voice, to work hard and to be respectful. They do work hard. The defining valúes in

  4. Uso y transformación en espacio agrario del monte y del estrato arbóreo en la Ribeira Sacra durante los siglos XIV y XV.

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    López Sabatel, José Antonio

    2009-12-01

    Full Text Available This article wants to show the importance that the mountain played in a rural economy orientated as much to the utilization of its natural resources as to its transformation in agrarian space. As in case of the mountain, the exploitation of the wooded stratum, will allow an approximation to the agrarian landscape of the Ribeira Sacra during the XIVth and XVth centuries.

    Este artículo quiere mostrar la importancia que desempeñó el monte en una economía campesina orientada tanto al aprovechamiento de sus recursos naturales como a su transformación en espacio agrario. Al igual que en el caso del monte, la explotación del estrato arbóreo, permitirá un acercamiento al paisaje agrario de la Ribeira Sacra durante los siglos XIV y XV.

  5. Recuerdos del monte pampeano. Una aproximación a un espacio cultural y simbólico

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    Graciela Hernández

    2007-07-01

    Full Text Available Nos proponemos reflexionar acerca de las características económicas y simbólicas del monte pampeano a partir del análisis de distintos tipos de registros documentales. Consideramos que una triangulación de fuentes nos puede dar una nueva mirada sobre el impacto de la llamada “Conquista del Desierto” sobre los pueblos indígenas -en este caso los ranqueles- y la transformación de las condiciones de vida, las que a pesar de los cambios aún permanecen en la memoria de los narradores.
    Las principales fuentes del trabajo son: testimonios orales seleccionados del Archivo Provincial de La Pampa, textos narrativos indígenas editados en una compilación de cuentos y leyendas realizada en esta provincia (Giovannoni y Poduje: 2002 y crónicas del siglo XIX como las de Luis de la Cruz, Santiago Avendaño y Lucio V. Mansilla.
    A partir de estos registros trataremos de escuchar las voces sobre distintos aspectos de la cultura del pasado, como las pautas de cocina, la elaboración de bebidas alcohólicas y su importancia en los rituales. También intentaremos identificar distintas temáticas de la narrativa que  nos señalan las características simbólicas delmonte.

  6. Propuesta de mejoras silvopastorales y de uso recreativo del monte "La Dehesa Boyal" de Collado Villalba (T.M. de Collado-Villalba, Madrid)

    OpenAIRE

    Durán Hernández, Esteban

    2011-01-01

    El Proyecto estudia la situación del monte "La Dehesa Boyal", propiedad del Ayuntamiento de Collado Villalba con el fin de proponer una serie de mejoras que combinen los usos selvícolas y pastorales junto con los recreativos.

  7. Memoria de prácticas en la biblioteca del seminario diocesano de Monte Corbán (Santander)

    OpenAIRE

    Vega Almeida, Daniel

    2014-01-01

    RESUMEN: En este Trabajo de Fin de Grado se muestran las tareas realizadas en la biblioteca del Seminario Diocesano de Monte Corbán (Santander, Cantabria) entre el 27 de febrero y el 27 de junio de 2014. Se tratarán de mostrar los conocimientos adquiridos y desarrollados, así como su aplicación práctica en la biblioteca. Gracias al estudio de bibliografía especializada y otras fuentes de información, la ayuda de tutores y una correcta organización y crítica de los materiales de trabajo, se el...

  8. Trabajadores, artesanos y trajinantes. La participación indígena en la economía minera del México colonial: Real del Monte en la segunda mitad del siglo XVIII

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    Navarrete G., David

    2015-01-01

    En este trabajo se estudia la participación de los indígenas en la minería novohispana en la segunda mitad del siglo XVIII. Para ello se examinan las distintas actividades económicas en las que intervino la población indígena de Real del Monte, un importante centro productor de plata del centro de México en dicha época. Hacen falta estudios sobre los sectores bajos de las sociedades mineras, en particular de la población indígena, comúnmente asociada con la figura de mano de obra no calificad...

  9. Un retiro para privilegiados: el Monte Athos a finales del siglo XIV. La compra de pensiones vitalicias

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    Estangüi Gómez, Raúl

    2005-06-01

    Full Text Available During the first half of the 14th century, the Byzantine Empire culminated in a serious political crisis which led to grave consequences in the society of the moment. The loss of great part of its territory in the hands of Serbians and Turks plunged a significant number of Byzantine landowners into poverty. Some of them sought refuge or means of subsistence by purchasing allowances (adelphata to the monasteries of the Mont Athos. At the end of the 14th century, the acquisition of such allowances has an important development amongst of the Byzantine-Slavic aristocracy, thus developing a complex system of relationship between the former power groups of the Balkan States and the Athonites monasteries. We set out to introduce the issue, far from being able to state it in all its complexity; we leave the matter open to future research

    Durante la primera mitad del siglo XIV, el imperio bizantino se precipitó en una fuerte crisis política que tendría graves consecuencias en la sociedad del momento. La pérdida de buena parte de su territorio a manos de serbios y turcos dejó a un número considerable de propietarios bizantinos en la pobreza. Algunos de éstos buscaron refugio o un medio de subsistencia a través de la compra de pensiones (adelphata a los monasterios del Monte Athos. La adquisición de dichas pensiones tuvo a fines del siglo XIV un importante desarrollo entre los miembros de la aristocracia bizantino-eslava, dando lugar a un complejo sistema de relaciones entre los antiguos grupos de poder de los estados balcánicos y los monasterios athonitas. Nos proponemos introducir el estado de la cuestión, lejos de poder exponerlo en toda su complejidad, dejamos la cuestión abierta para futuras investigaciones.

  10. Monte Carlo analysis of the Neutron Standards Laboratory of the CIEMAT; Analisis Monte Carlo del Laboratorio de Patrones Neutronicos del CIEMAT

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Mendez V, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Av. Complutense 40, 28040 Madrid (Spain); Guzman G, K. A., E-mail: fermineutron@yahoo.com [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain)

    2014-10-15

    By means of Monte Carlo methods was characterized the neutrons field produced by calibration sources in the Neutron Standards Laboratory of the Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT). The laboratory has two neutron calibration sources: {sup 241}AmBe and {sup 252}Cf which are stored in a water pool and are placed on the calibration bench using controlled systems at distance. To characterize the neutrons field was built a three-dimensional model of the room where it was included the stainless steel bench, the irradiation table and the storage pool. The sources model included double encapsulated of steel, as cladding. With the purpose of determining the effect that produces the presence of the different components of the room, during the characterization the neutrons spectra, the total flow and the rapidity of environmental equivalent dose to 100 cm of the source were considered. The presence of the walls, floor and ceiling of the room is causing the most modification in the spectra and the integral values of the flow and the rapidity of environmental equivalent dose. (Author)

  11. Un progetto per l'attivazione di Agenda 21 Locale: monitoraggio della mammalofauna nell'area del Parco Regionale del Monte Cucco (Perugia

    Directory of Open Access Journals (Sweden)

    Roberta Mazzei

    2003-10-01

    Full Text Available Nell?ambito del progetto ?Attivazione Agenda 21 Locale? finalizzato alla realizzazione di studi per la certificazione e contabilizzazione ambientale, nel Parco Regionale del Monte Cucco, si è dato il via, a partire dal novembre del 2001, ad un?indagine di tipo qualitativo, mirata alla caratterizzazione dell?area Parco per quel che riguarda la presenza di specie di Mammiferi appenninici di interesse conservazionistico e naturalistico. Nel periodo che va dall?8 febbraio 2002 al 5 ottobre dello stesso anno, sono stati effettuati 16 transetti faunistici, distribuiti nell?arco delle quattro stagioni. Sono stati raccolti indici di presenza di 11 specie di Mammiferi appartenenti agli ordini degli Artiodattili, Carnivori, Lagomorfi, Insettivori e Roditori e i relativi IKA (indici chilometrici di abbondanza. I dati raccolti unitamente ad una ricognizione bibliografica, mirata a reperire informazioni pregresse e aggiornate sulla teriofauna locale, attraverso inoltre, l?effettuazione di interviste e il coinvolgimento della popolazione locale, hanno portato alla definizione di una Check-list della Mammalofauna del Parco, rappresentativa per il 56% di quella della Regione. La ricerca ha permesso di confermare per l?area la presenza del Lupo (Canis lupus e di evidenziare l?espansione a Sud del Capriolo (Capreolus capreolus. Parte integrante del progetto ?Cucco 21? era la definizione di proposte gestionali volte a migliorare il rapporto uomo-ambiente, laddove fossero state individuate situazioni di criticità oggettive o potenziali, in un?ottica di conservazione della risorsa naturale e di sviluppo delle attività antropiche. Significativi a tale proposito sono stati il caso del Cinghiale (Sus scrofa con l?osservazione del danno alle fitocenosi, soprattutto ai prati e pascoli cacuminali e del Capriolo. Per quest?ultima specie in funzione della sua espansione verso la parte meridionale del Parco, sono state avanzate delle

  12. Paleolimnología de la Laguna Cerrillo del medio, Monte, provincia de Buenos Aires Paleolimnology of Laguna Cerrillo del Medio, Monte, Buenos Aires Province

    Directory of Open Access Journals (Sweden)

    Nauris V. Dangavs

    2008-03-01

    Full Text Available Se caracterizaron el medio físico del ambiente, la fisiografía, el sistema geomorfológico de la región, las características hidrológicas y el origen de la cubeta lagunar. La geología superficial está definida por diez unidades estratigráficas (siete litoestratigráficas y tres pedoestratigráficas. La más antigua es la Formación Ensenada del Pleistoceno medio, que constituye el sustrato regional, donde se excavó la cubeta lagunar. Encima se dispone la Formación Buenos Aires del Pleistoceno tardío, en cuya parte cuspidal se sitúa un Geosuelo Sin Nombre. Las siguientes cuatro unidades corresponden a depósitos eólicos de dunas de arcilla y loéssicos de la Formación La Postrera I, II, III y IV, de edades dispares, que abarcan desde el Pleistoceno tardío al Holoceno tardío-tardío. La Formación La Postrera II y III poseen los Geosuelos Puesto Callejón Viejo y Puesto Berrondo respectivamente. En las playas afloran depósitos aluviales, que incrementan su espesor en el lecho lagunar. En los sedimentos colmatantes se reconocieron seis depósitos, cinco representan a ambientes acuáticos: Formación Luján, Miembros La Chumbiada, Lobos y Río Salado, del Pleistoceno tardío al Holoceno temprano a medio; formación subaluvial del Holoceno tardío y la actual formación aluvial. El sexto es un depósito eólico de duna de arcilla intracuencal del Pleistoceno tardío. El conjunto de los depósitos suprayacentes a la Formación Ensenada supera los 64 ka, representados por cinco episodios de clima seco que abarcan desde el loess Bonaerense hasta la pequeña edad de hielo (IS4, IS2, D3-L3, D2-L2, D1-L1 y cinco húmedos (IS3, S3, IS1, S1 y el actual.The regional physical environment was characterized, describing the physiographic and geomorphic features, the hydrologic regime and the origin of the shallow lake basin. The surficial geology is defined by ten stratigraphic units (seven lithostratigraphic units and three geosols; the oldest

  13. Inventario y estudio de regeneración de Pinus sylvestris L. en los cuarteles A y B del Monte "Cabeza de Hierro" (Rascafría, Madrid)

    OpenAIRE

    Rubio Cuadrado, Álvaro

    2008-01-01

    En el presente trabajo se estudian los factores que más inciden en la aparición del suficiente regenerado para la persistencia de la masa de pino silvestre, en la estructura deseada y por medio de la dispersión de semillas, de los cuarteles A y B del monte “Cabeza de Hierro”, situado en el término municipal de Rascafría (Madrid). A partir del conocimiento de dichos factores se proporcionan unos valores orientativos que deben alcanzar para conseguir la aparición del suficiente regenerado en fu...

  14. Geología y geoquímica del granito de Montánchez (Cáceres

    Directory of Open Access Journals (Sweden)

    Arribas Moreno, A.

    1989-12-01

    Full Text Available The granite of Montánchez (Cáceres, Spain is located to the S.E. of the Albalá granite and is separated from it by a strongly tectonized zone. According to the mica content, three perografic facies have been distinguished in the Montánchez granite. Facies 1, is made up of medium to coarse grained, two mica granites richer in muscovite, which occupy the northern half of the granite and have been extremely deformed. Facies II, consiting of coarse to very coarse grained, sometimes porphyrblastic, two-mica granites, richer in biotite, has not been deformed, or very little. Facies III is made up of aplitic muscovite granties which are poor in biotite and rich in tourmaline. The Montánchez granite frecuently contains tonalitic xenolith, sometimes quitee large. Regarding the geochemistry of the Montánchez granite the major and some trace elements have been analyzed on 22 samples belonging to the three different facies and the tonalitic xenoliths. As for the major elements, the chemical-mineralogical parameters of la Roche, the binary diagrams of Harker, Larsen, la Roche and Deban and Le Fort, and the ternary diagrams Na2O, K2O, CaO, Na2O+K2O, Al2O3, CaO and AFM have been calculted. They indicate that these granties are made up alkaline rocks richer in Na than K, poor in Ca, and with a markedly peraluminous character. Concerning the distribution of the trace elements in the Montánchez granite the average conten in Rb, Ba, Sr, Zr and Nb lower and those in Sn and Zn higher, than the values reported by different autors for several world granites considered to be standard.El macizo granítico de Montánchez (Cáceres, España está situado al SE del granito de Albalá, del que le separa una banda fuertemente tectonizada. De acuerdo con su contenido en micas se han distinguido en él tres facies petrográficas. Facies 1, formada por grantios de dos micas, con moscovita dominante, ocupa la parte norte del macizo; es una facies muy deformada y con tama

  15. Livestock grazing, habitat protection and diversity of bees and wasps in the Central Monte desert Ganadería, protección del hábitat y diversidad de abejas y avispas en el desierto del Monte Central

    Directory of Open Access Journals (Sweden)

    Diego P. Vázquez

    2008-12-01

    Full Text Available Reserves aim mainly at preventing or mitigating human impacts on natural ecosystems. It is important to assess how well reserves meet this goal. We evaluated whether habitat protection offered by Ñacuñán Biosphere Reserve (Central Monte desert, Argentina results in detectable changes in habitat structure and the species richness and composition of bees and wasps. We conducted pan trap sampling and flower visitor observations in six pairs of protected and unprotected sites. Our results suggest that thirty fi ve years of cattle exclusion in Ñacuñán have had detectable effects on habitat structure. However, these changes in habitat structure translated only into partial and conflicting effects on hymenopteran richness, and did not have detectable effects on hymenopteran composition. Our study should be repeated with a greater sampling effort and throughout multiple years before our results can be applied to guide management decisions.El principal objetivo de las reservas es prevenir o mitigar los impactos humanos sobre los ecosistemas naturales. Es importante evaluar cuán bien las reservas alcanzan este objetivo. Evaluamos si la protección del hábitat que brinda la Reserva de la Biósfera de Ñacuñán (Monte Central, Argentina resulta en cambios detectables en la estructura del hábitat, y en la riqueza y la composición de especies de abejas y avispas. Realizamos muestreos con trampas bandeja y observaciones de visitantes florales en seis pares de sitios dentro y fuera de la reserva. Nuestros resultados sugieren que los treinta y cinco años de exclusión del ganado vacuno en Ñacuñán han tenido efectos detectables sobre la estructura del hábitat. Sin embargo, estos cambios en el hábitat se tradujeron sólo en efectos parciales y conflictivos sobre la riqueza de himenópteros, y no tuvieron efectos detectables sobre la composición de himenópteros. Nuestro estudio debería repetirse en el futuro, con un mayor esfuerzo de muestreo y

  16. Environmental and ecological architects: Guidelines for the Chilean temperate rainforest management derived from the monito del monte (Dromiciops gliroides conservation Arquitectos ambientales y ecológicos: Pautas para la gestión ambiental del bosque templado lluvioso de Chile derivadas de la conservación del monito del monte (Dromiciops gliroides

    Directory of Open Access Journals (Sweden)

    FRANCISCO E FONTÚRBEL

    2011-06-01

    Full Text Available Land use change is one of the main biodiversity threats. Due to this change, natural habitats such as the South American temperate rainforests have been rapidly degraded, fragmented, and lost. Consequently, the management and conservation of the remaining forest is a priority and having an appropriate environmental policy is mandatory for this purpose. Conservation actions in the temperate rainforest have been addressed from an individual species perspective, giving less attention to the ecosystem level conservation. Moreover, conservation-related information has not reflected yet on environmental policy development. We used the case study of the monito del monte (Dromiciops gliroides to illustrate how our current ecological and conservation knowledge of a species could be used to generate a new environmental policy. Dromiciops gliroides is a forest-dependent species with an important ecological role and quite unique evolutionary status. In order to guarantee the persistence of D. gliroides, we propose two habitat management components to be incorporated in management plans: structure and connectivity. Structure refers to spatial arrangement and key structural elements that determine habitat quality and connectivity refers to functional connectivity at the landscape level. The conservation of the monito del monte might also contribute to the conservation of many other forest-dependent species. By conserving such species it will be possible to conserve the ecological interactions and the eco-evolutionary processes, which ultimately determine the conservation of the temperate rainforest.El cambio de uso de la tierra es una de las principales amenazas a la biodiversidad. Hábitats naturales como el bosque templado lluvioso de Sudamérica han sido degradados, fragmentados y eliminados rápidamente. En consecuencia, es prioritario el manejo y conservación de los remanentes, para lo que es necesario contar con una política ambiental acorde. Las

  17. Petrogenesis of fertile mantle peridotites from the Monte del Estado massif (southwest Puerto Rico): a preserved section of Proto-Caribbean oceanic lithospheric mantle?

    Science.gov (United States)

    Marchesi, Claudio; Jolly, Wayne T.; Lewis, John F.; Garrido, Carlos J.; Proenza, Joaquín. A.; Lidiak, Edward G.

    2010-05-01

    The Monte del Estado massif is the largest and northernmost serpentinized peridotite belt in southwest Puerto Rico. It is mainly composed of spinel lherzolite and minor harzburgite with variable clinopyroxene modal abundances. Mineral and whole rock major and trace element compositions of peridotites coincide with those of fertile abyssal peridotites from mid ocean ridges. Peridotites lost 2-14 wt% of relative MgO and variable amounts of CaO by serpentinization and seafloor weathering. HREE contents in whole rock indicate that the Monte del Estado peridotites are residues after low to moderate degrees (2-15%) of fractional partial melting in the spinel stability field. However, very low LREE/HREE and MREE/HREE in clinopyroxene cannot be explained by melting models of a spinel lherzolite source and support that the Monte del Estado peridotites experienced initial low fractional melting degrees (~ 4%) in the garnet stability field. The relative enrichment of LREE in whole rock is not due to secondary processes but probably reflects the capture of percolating melt fractions along grain boundaries or as microinclusions in minerals, or the presence of exotic micro-phases in the mineral assemblage. We propose that the Monte del Estado peridotite belt represents a section of ancient Proto-Caribbean (Atlantic) lithospheric mantle originated by seafloor spreading between North and South America in the Late Jurassic-Early Cretaceous. This portion of oceanic lithospheric mantle was subsequently trapped in the forearc region of the Greater Antilles paleo-island arc generated by the northward subduction of the Caribbean plate beneath the Proto-Caribbean ocean. Finally, the Monte del Estado peridotites belt was emplaced in the Early Cretaceous probably as result of the change in subduction polarity of the Greater Antilles paleo-island arc without having been significantly modified by subduction processes.

  18. Los grabados del Monte Bego y el arte esquemático

    OpenAIRE

    2009-01-01

    Uno de los más característicos fenómenos de la pintura rupestre en la Península Ibérica es el arte esquemático. No es uniforme. Más bien este título indica muy diferentes pinturas en las paredes de los abrigos. Tienen en común solamente el hecho, que son poco o de ningún modo naturalísticas, que muchas veces muestran símbolos y que no forman parte del arte paleolítico o del arte levantino de los tiempos postglaciales.

  19. Edificio de oficinas del Monte de Piedad y Caja de Ahorros de Sevilla-España

    Directory of Open Access Journals (Sweden)

    Población Knappe, Eleuterio

    1981-03-01

    Full Text Available Architect The essential feature of the new building of the Pawnshop and Savings Bank in Seville, built on a site in an «L» form and affected in the course of the planning and building by successive changes of Ordenances, its attempt to harmonize with the surrounding architecture, respecting its traditional characteristics. The building, which has seven stories on a slope and two basements, broadcasts its different private and public missions by the volumes, forms and different exterior treatments, presenting particular attention to its functionality in accordance with the initial programme proposed by the organisation.

    La característica esencial de la nueva sede del Monte de Piedad y Caja de Ahorros de Sevilla, levantada sobre un solar en forma de «L» y afectada en el transcurso del proyecto y construcción por sucesivos cambios de Ordenanzas, armoniza con la arquitectura circundante, respetando sus características tradicionales. La edificación, de siete plantas sobre rasante y dos sótanos, patentiza su distinta misión privada y de cara al público a través de los volúmenes, formas y diferentes tratamientos exteriores, presentando una especial atención a su funcionalidad de acuerdo con el programa inicial planteado por la entidad.

  20. Distribución espacial de los bosques nativos en el norte del Monte argentino, hacia mediados del siglo XIX

    Directory of Open Access Journals (Sweden)

    Facundo Rojas

    2014-12-01

    Full Text Available The objective of this investigation was to reconstruct the middle 19th century distribution of the native forest in the western valleys of the Monte Desert. The goal was to generate a baseline for understanding the status of algarrobales y retamales (Prosopis flexuosa y Bulnesia retama just prior to large-scale exploitation, first by mining activities and then the construction of the railway. The sources used were traveler’s diaries, business documents, descriptions by early naturalists, information provided by expeditions, scientific publications and government documents. Through the analysis of these data sources, the total surface area of native forests was estimated for 1850, as well as approximated limits of principal clusters of native forests. The study began with the assumption that the historic distribution of native forests would have had a high spatial correlation with the most densely populated and agricultural areas, where there would have been accentuated competition for use of the region’s land and natural resources.

  1. Paleolimnología de la Laguna Cerrillo del medio, Monte, provincia de Buenos Aires

    Directory of Open Access Journals (Sweden)

    Nauris V. Dangavs

    2008-03-01

    Full Text Available Se caracterizaron el medio físico del ambiente, la fisiografía, el sistema geomorfológico de la región, las características hidrológicas y el origen de la cubeta lagunar. La geología superficial está definida por diez unidades estratigráficas (siete litoestratigráficas y tres pedoestratigráficas. La más antigua es la Formación Ensenada del Pleistoceno medio, que constituye el sustrato regional, donde se excavó la cubeta lagunar. Encima se dispone la Formación Buenos Aires del Pleistoceno tardío, en cuya parte cuspidal se sitúa un Geosuelo Sin Nombre. Las siguientes cuatro unidades corresponden a depósitos eólicos de dunas de arcilla y loéssicos de la Formación La Postrera I, II, III y IV, de edades dispares, que abarcan desde el Pleistoceno tardío al Holoceno tardío-tardío. La Formación La Postrera II y III poseen los Geosuelos Puesto Callejón Viejo y Puesto Berrondo respectivamente. En las playas afloran depósitos aluviales, que incrementan su espesor en el lecho lagunar. En los sedimentos colmatantes se reconocieron seis depósitos, cinco representan a ambientes acuáticos: Formación Luján, Miembros La Chumbiada, Lobos y Río Salado, del Pleistoceno tardío al Holoceno temprano a medio; formación subaluvial del Holoceno tardío y la actual formación aluvial. El sexto es un depósito eólico de duna de arcilla intracuencal del Pleistoceno tardío. El conjunto de los depósitos suprayacentes a la Formación Ensenada supera los 64 ka, representados por cinco episodios de clima seco que abarcan desde el loess Bonaerense hasta la pequeña edad de hielo (IS4, IS2, D3-L3, D2-L2, D1-L1 y cinco húmedos (IS3, S3, IS1, S1 y el actual.

  2. Tamaño y composición de la colonia de tres especies de hormigas del género Pogonomyrmex (Hymenoptera: Formicidae en la porción central del desierto del Monte, Argentina

    Directory of Open Access Journals (Sweden)

    Beatriz E. NOBUA BEHRMANN

    2010-01-01

    Full Text Available El tamaño de la colonia es un atributo fundamental de la biología de las hormigas ya que está asociado a características ecológicamente relevantes, como sus estrategias de alimentación. Mientras que el tamaño de la colonia de varias especies de hormigas granívoras del género Pogonomyrmex de América del Norte se ha estudiado en detalle, no existe tal información para las especies de América del Sur. En este trabajo, se determinó el tamaño y la composición de la colonia y se describió la estructura del nido de tres especies de Pogonomyrmex que habitan la porción central del desierto del Monte en Argentina: P. mendozanus Cuezzo & Claver, P. inermis Forel y P. rastratus Mayr. Para ello, se excavaron dos nidos de cada especie y se recolectaron todos los individuos encontrados. Las tres especies tienen colonias pequeñas, compuestas por 300-1.100 individuos, de los cuales aproximadamente el 70% son obreras adultas. La estructura de sus nidos es relativamente simple, similar a la de la mayoría de las especies norteamericanas estudiadas, pero con un menor desarrollo en profundidad y un número menor de cámaras; probablemente se deba al menor número de obreras que poseen. Estas características (colonias pequeñas y nidos poco desarrollados son consideradas típicas para las especies del género Pogonomyrmex de América del Sur, lo que las diferencia de la mayoría de sus congéneres estudiados en América del Norte.

  3. La influencia del monte arbolado en las empresas transformadoras de la madera en Galicia

    OpenAIRE

    Alonso Logroño, María Pilar

    2013-01-01

    En los estudios sobre la conformación de sistemas productivos empresariales se olvida cada vez más, la significación que puede tener para su conformación y éxito la presencia de materia prima cercana. Es cierto, que los avances en los medios de transporte, entre otros condicionantes, facilitan que se aleje el lugar de transformación del de suministro de la materia prima. Sin embargo, en muchas actividades la presencia fabril está todavía muy condicionada por la localización y características ...

  4. Nueva pasarela peatonal en Boadilla del Monte sobre la carretera M-513

    OpenAIRE

    Delgado Olea, Joaquín

    2014-01-01

    El presente Proyecto de Construcción se enmarca dentro de las labores de urbanización la zona de “Valenoso”, que incluye la construcción de un gran número de viviendas, tanto unifamiliares como multifamiliares, y la construcción “Parque del Deporte y la Salud”, ubicado en la zona “Residencial Siglo XXI” en una parcela de 45.000 m2. La urbanización de esta nueva zona cuenta con el problema de la existencia de la carretera M-513, que crea un importante efecto barrera a la comunicación. ...

  5. Quality control of the new Monte Carlo code Multi plan for Cyberknife planner; Control de calidad del nuevo codigo Monte Carlo de planificador multiplan para Cyberknife

    Energy Technology Data Exchange (ETDEWEB)

    Fayos Ferrer, F.; Antolin Sanmartin, E.; Simon de Blas, R.; Palazon Cano, I.; Bertomeu Padin, T.; Gutierrez Sarraga, J.; Rey Portoles, G.

    2011-07-01

    This paper is subjected to various tests including Monte Carlo dosimetric the code in the latest versions of Multi plan Accuracy planner. They compare their results and Ray-Tracing Algorithm (RT), present from the earliest versions, with the experimental results obtained by photographic dosimetry and ionization chamber measurements.

  6. La artesanía como producción cultural susceptible de ser atractivo turístico en Santa Catarina del Monte, Texcoco

    OpenAIRE

    2008-01-01

    El medio rural ofrece una alternativa económica basada en el binomio naturaleza y cultura. Los recursos naturales son un atractivo turístico que junto con las peculiaridades culturales diferencian unas zonas de otras, otorgándoles una identidad propia. En Santa Catarina del Monte se conjugan estas características naturales y culturales en la elaboración de artesanía de vara, que reproduce piezas con motivos navideños. El turismo rural es considerado como un motor del desarrollo en esta zona, ...

  7. SIMULACIÓN MOLECULAR DEL EQUILIBRIO LÍQUIDO-VAPOR DE LA MEZCLA N2-NC5 POR SIMULACIONES MONTE CARLO

    OpenAIRE

    Florianne Castillo-Borja; Richart Vázquez-Román; Ulises I. Bravo-Sánchez

    2013-01-01

    En este trabajo se usaron simulaciones Monte Carlo en el colectivo de Gibbs para describir el equilibrio de fases liquido-vapor del sistema nitrógeno-n-pentano para tres isotermas. Se analizó un amplio rango de presiones que consideran hasta los 25 MPa. El sistema fue modelado usando los potenciales intermoleculares Galassi-Tildesley para el nitrógeno y SKS para el n-pentano. Los resultados obtenidos fueron comparados contra datos experimentales. Lejos de la región del punto crítico los model...

  8. Estudio de la cubierta vegetal del Monte Forgoselo mediante imágenes de Landsat TM 5 (Galicia, NW España

    Directory of Open Access Journals (Sweden)

    Xana Álvarez-Bermúdez

    2015-01-01

    Full Text Available En el estudio que a continuación se describe, se pretende realizar una clasificación de la cubierta vegetal del Monte Forgoselo. Para ello hemos utilizado la Teledetección como herramienta, concretamente una imagen del satélite Landsat 5. Hemos realizado una clasificación digital supervisada de máxima probabilidad, de mínima distancia y de paralelepípedos. El resultado ha sido la división del Monte Forgoselo en categorías de estratos de vegetación, concretamente en pinar, matorral y pradera, alcanzando un coeficiente Kappa del 0,9762 y una precisión total del 98,3586%, lo que se traduce en una buena fiabilidad, Con nuestro estudio hemos comprobado que con el uso de dichas técnicas se puede llegar a realizar una ordenación de esta pequeña área rural, centrándose en el ámbito forestal. Así mismo, se concluye que el empleo de la Teledetección se considera factible en la realización de trabajos de mayor envergadura.

  9. Población y ocupación del espacio en la frontera del salado. Chascomús, Ranchos y Monte entre 1815 y 1838

    Directory of Open Access Journals (Sweden)

    Guillermo Banzato

    2000-06-01

    Full Text Available Los numerosos estudios sobre la sociedad rural rioplatense en el período colonial y pos independiente van mostrando, poco a poco, las características de la población, la composición familiar y la disponibilidad de mano de obra, tanto en las áreas de viejo asentamiento como en las más dinámicas de la frontera interior, de manera que puede continuarse la tarea con nuevas aproximaciones, comparando los resultados con los ya obtenidos. Esta será la perspectiva del presente trabajo, en el que se describirá la estructura poblacional de Chascomús entre 1815 y 1838, aunque sumando una relación que se aprecia ausente en los trabajos sobre el tema, como es la ocupación y acceso a la propiedad legal de la tierra. Debido a las características de las fuentes los partidos de Ranchos y Monte se incluirán parcialmente en el análisis

  10. Simulation of the functioning of a gamma camera using Monte Carlo method; Simulacion del funcionamiento de una camara gamma mediante metodo Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Oramas Polo, I.

    2014-07-01

    This paper presents the simulation of the gamma camera Park Isocam II by Monte Carlo code SIMIND. This simulation allows detailed assessment of the functioning of the gamma camera. The parameters evaluated by means of the simulation are: the intrinsic uniformity with different window amplitudes, the system uniformity, the extrinsic spatial resolution, the maximum rate of counts, the intrinsic sensitivity, the system sensitivity, the energy resolution and the pixel size. The results of the simulation are compared and evaluated against the specifications of the manufacturer of the gamma camera and taking into account the National Protocol for Quality Control of Nuclear Medicine Instruments of the Cuban Medical Equipment Control Center. The simulation reported here demonstrates the validity of the SIMIND Monte Carlo code to evaluate the performance of the gamma camera Park Isocam II and as result a computational model of the camera has been obtained. (Author)

  11. La influencia del monte arbolado en las empresas transformadoras de la madera en Galicia

    Directory of Open Access Journals (Sweden)

    Miramontes Carballada, Ángel

    2013-06-01

    Full Text Available In studies on the creation of corporate production systems, the significance that the proximity of raw material can have on its success and creation is increasingly overlooked. It is true that advances in transportation, among other conditions, make it easy to move the processing plant farther away from where the raw material is supplied. However, in many activities the manufacturing location is still conditioned by the location and characteristics of the materials used in production. A good example is the timber industry. This article specifically focuses on showing the relationship, significance and economic potential of forest raw materials and the wood processing industry in Galicia.En los estudios sobre la conformación de sistemas productivos empresariales se olvida cada vez más, la significación que puede tener para su conformación y éxito la presencia de materia prima cercana. Es cierto, que los avances en los medios de transporte, entre otros condicionantes, facilitan que se aleje el lugar de transformación del de suministro de la materia prima. Sin embargo, en muchas actividades la presencia fabril está todavía muy condicionada por la localización y características de los materiales con los que fabricar. Un buen ejemplo es la industria de la madera. En concreto este artículo se centra en mostrar la relación, significación y potencialidad económica de la materia prima forestal y la industria de transformación de la madera en Galicia. [fr] Les études sur la formation des systèmes productifs commerciaux oublient de plus en plus l’importance que peut avoir pour leur formation et leur succès la présence proche de matières premières. Il est vrai que les progrès des moyens de transport, parmi d’autres autres conditions, facilitent l’éloignement du lieu de transformation de celui d’approvisionnement de la matière première. Cependant, en de nombreuses activités, la présence d’usines est encore fortement

  12. Study of the effect of usual heterogeneities in brachytherapy using Monte Carlo simulation; Estudio del efecto de heterogeneidades usuales en braquiterapia mediante simulacion Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Vera Sanchez, J. A.; Ruiz Morales, C.; Tobarra Gonzalez, B. M.

    2013-07-01

    The majority of current planning in brachytherapy systems don't count the composition of materials they form applicators, or the characteristics of the main interfaces present in the treatments. The objective of this study It is to compare the dosimetry distributions obtained by Monte Carlo simulations in geometric mannequins that they represent general features of the treatments that we find in our clinical practice, with results calculated according to the TG-43 formalism based on the existing consensus data for Ir-192 mHDR-v2 source. (Author)

  13. Balance y modelización del acuífero karstico de los Montes Torozos (Valladolid, España

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    Germán Sanz-Lobón

    2015-01-01

    Full Text Available En este trabajo se presenta el balance hídrico de una masa de agua subterránea de naturaleza kárstica de la cuenca sedimentaria del Duero, centro oeste de España. Los datos obtenidos para la realización del balance han sido introducidos en una herramienta de simulación con el fin de conocer la evolución temporal de los recursos hídricos a lo largo del año hidrológico. Para ello se ha sido necesario recurrir a la utilización de técnicas geostadísticas y el programa Visual Modflow. La masa de agua de los Montes Torozos se trata de un acuífero kárstico libre y colgado de origen sedimentario, y su balance está determinado por las precipitaciones y por el drenaje.

  14. Efectos del tipo de cambio sobre el déficit público: modelos de simulación Monte Carlo

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    Abigail Rodríguez Nava

    2010-01-01

    Full Text Available En este documento se estudian los efectos de las variaciones del tipo de cambio sobre el déficit público. Para ello, se extienden los modelos deterministas del balance público, incorporando como supuestos que la variación del tipo de cambio puede describirse mediante un proceso estocástico, y que sus movimientos extremos y repentinos siguen un proceso Poisson; las ecuaciones que describen la dinámica de las fluctuaciones del tipo de cambio se construyen en analogía con los procesos Ornstein-Uhlenbeck y de raíz cuadrada. Con estos supuestos, y mediante simulación Monte Carlo, se estima la variación del tipo de cambio peso-dólar estadounidense y el déficit público asociado para la economía mexicana entre 1990 y 2008. Los resultados obtenidos son consistentes con la evidencia empírica real de esos años, esto indica que la metodología sugerida puede ser útil como herramienta ex ante para la determinación del presupuesto público.

  15. Políticas agroambientales y ganadería en los montes de utilidad pública del País Vasco

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    Juan Cruz Alberdi Collantes

    2003-01-01

    Full Text Available Los terrenos y montes comunales han sido un recurso fundamental en la sociedad agraria vasca aportando toda una serie de aprovechamientos básicos para su funcionamiento como eran pastos, madera, helechales, agua, … Con su urbanización progresiva la explotación de muchos de sus recursos deja de tener sentido y estos espacios pasan a cumplir otras funciones, como áreas naturales, turísticas e incluso deportivas. Algunos aprovechamientos tradicionales perviven aunque han de adecuarse a las nuevas inquietudes sociales, como son las actividades ganaderas, que continúan cumpliendo una función básica en el mantenimiento del monte. Cambia su organización tradicional, antiguas prácticas de pastoreo son prohibidas y se recomiendan nuevas, los usos y áreas de aprovechamiento son delimitados. En definitiva, se incorporan conceptos medioambientales que contribuyen al correcto mantenimiento de estos espacios.

  16. Agua y sociedad rural en los montes de Málagasistemas hidráulicos en el hábitat disperso del s. XIX

    OpenAIRE

    Blanco Sepúlveda, Rafael; Gómez Moreno, María Luisa

    2006-01-01

    En un contexto social y académico de preocupación por la escasez de los recursos hídricos, y de interés por la conservación del patrimonio etnográfico, el artículo aborda la relación entre sociedad y agua en la montaña mediterránea, en el ámbito de los Montes de Málaga. Para ello, se ha analizado la relación entre los recursos hídricos existentes y los sistemas adoptados para su aprovechamiento en el hábitat disperso tradicional. Los recursos hídricos de los Montes de Málaga, m...

  17. Florística e fitossociologia de espécies arbóreas e arbustivas em uma área de Caatinga em Arcoverde, PE, Brasil

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    Mozart Duarte Barbosa

    2012-10-01

    Full Text Available Os estudos de florística e fitossociologia contribuem significativamente para o conhecimento das formações florestais, visto que evidenciam a riqueza e heterogeneidade dos ambientes avaliados. O trabalho foi realizado em um fragmento de Caatinga hipoxerófila no Município de Arcoverde, PE, e teve como objetivo verificar a composição florística e parâmetros fitossociológicos das espécies arbóreas e arbustivas que compõem o fragmento. O estudo foi realizado em 40 parcelas de 10 x 25 m, sendo o nível de inclusão a circunferência a 1,3 m do solo com CAP > 10 cm. Foram estimados a densidade absoluta e relativa, a frequência absoluta e relativa, a dominância absoluta e relativa e o valor de importância; a diversidade específica foi dada pelo índice de diversidade de Shannon - Weaver (H' e equabilidade de Pielou, sendo determinada a distribuição hipsométrica em intervalos de 1 m e distribuição diamétrica em intervalos com amplitude de 3 cm. No levantamento florístico das adultas, foram encontrados 1.491 indivíduos vivos, distribuídos em 36 espécies arbóreo-arbustivas, 19 famílias e 31 gêneros. As famílias que mais se destacaram foram Mimosaceae, Euphorbiaceae, Anacardiaceae, Caesalpiniaceae e Rhamnaceae. O índice de diversidade de Shannon-Weaver foi de 2,05 nats/ind. e a equabilidade de Pielou, de 0,57. Nos sete parâmetros fitossociólogicos avaliados, as espécies que mais se destacaram foram Mimosa ophthalmocentra, Poincianella pyramidalis, Senegalia bahiensis, Senegalia paniculata, Croton blanchetianus e Mimosa tenuiflora, indicando ser essas espécies as mais bem adaptadas ao ambiente avaliado, tanto nas condições edafoclimáticas quanto na competição com as demais espécies presentes no fragmento de Caatinga em Arcoverde, PE.

  18. Application of a Monte Carlo Penelope code at diverse dosimetric problems in radiotherapy; Aplicacion del codigo Monte Carlo Penelope a diversos problemas dosimetricos en radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, R.A.; Fernandez V, J.M.; Salvat, F. [Servicio de Oncologia Radioterapica. Hospital Clinico de Barcelona. Villarroel 170 08036 Barcelona (Spain)

    1998-12-31

    In the present communication it is presented the results of the simulation utilizing the Penelope code (Penetration and Energy loss of Positrons and Electrons) in several applications of radiotherapy which can be the radioactive sources simulation: {sup 192} Ir, {sup 125} I, {sup 106} Ru or the electron beams simulation of a linear accelerator Siemens KDS. The simulations presented in this communication have been on computers of type Pentium PC of 100 throughout 300 MHz, and the times of execution were from some hours until several days depending of the complexity of the problem. It is concluded that Penelope is a very useful tool for the Monte Carlo calculations due to its great ability and its relative handling facilities. (Author)

  19. Characterization of Siemens Bio graph 6 PET by Monte Carlo simulation; Caracterizacion del escaner PET Biograph 6 de Siemens mediante simulacion Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Gallego Franco, P.; Garcia Marcos, R.

    2015-07-01

    GAMOS simulation code based on Geant4 is a very powerful tool for the design and modeling optimization on Positron Emission Tomography (PET) systems. In order to obtain a proper image quality, it results to be extremely important determine the optimal activity which is going to be delivered. For this reason a study about the internal system parameters that affects image quality, such as scatter fraction (SF) and the count rate equivalent noise (NEC), has been carried out. The study involves the comparison of experimental measures on both parameters, with those obtained by Monte Carlo simulation of Siemens Pet Biograph 6 True Point with True V option. Based on simulations results, a paralizable dead-time model that adjusts, depending on the activity provided, the proper dead-time for scanner detectors. Also a study about the variation of this proper dead-time with the activity has been carried out. (Author)

  20. SIMULACIÓN MOLECULAR DEL EQUILIBRIO LÍQUIDO-VAPOR DE LA MEZCLA N2-NC5 POR SIMULACIONES MONTE CARLO

    Directory of Open Access Journals (Sweden)

    Florianne Castillo-Borja

    2013-01-01

    Full Text Available En este trabajo se usaron simulaciones Monte Carlo en el colectivo de Gibbs para describir el equilibrio de fases liquido-vapor del sistema nitrógeno-n-pentano para tres isotermas. Se analizó un amplio rango de presiones que consideran hasta los 25 MPa. El sistema fue modelado usando los potenciales intermoleculares Galassi-Tildesley para el nitrógeno y SKS para el n-pentano. Los resultados obtenidos fueron comparados contra datos experimentales. Lejos de la región del punto crítico los modelos analizados reproducen favorablemente la forma de la curva del equilibrio de fases y en la cercanía del punto crítico los resultados tienden a alejarse del comportamiento experimental. Se determinaron los puntos críticos (presión, densidad y composición para las tres isotermas usando un método de extrapolación basado en leyes de escalamiento, obteniéndose resultados satisfactorios. Las curvas de coexistencia calculadas son adecuadas aun cuando los modelos analizados no contienen parámetros de interacción binaria optimizados.

  1. Tamaño y composición de la colonia de tres especies de hormigas del género Pogonomyrmex (Hymenoptera: Formicidae en la porción central del desierto del Monte, Argentina Colony size and composition in three Pogonomyrmex ant species (Hymenoptera: Formicidae in the central Monte desert, Argentina

    Directory of Open Access Journals (Sweden)

    Beatriz E. Nobua Behrmann

    2010-06-01

    Full Text Available El tamaño de la colonia es un atributo fundamental en la biología de las hormigas ya que está asociado a características ecológicamente relevantes, como sus estrategias de alimentación. Mientras que el tamaño de la colonia de varias especies de hormigas granívoras del género Pogonomyrmex de América del Norte se ha estudiado en detalle, no existe tal información para las especies de América del Sur. En este trabajo, se determinó el tamaño y la composición de la colonia y se describió la estructura del nido de tres especies de Pogonomyrmex que habitan la porción central del desierto del Monte en Argentina: P. mendozanus Cuezzo & Claver, P. inermis Forel y P. rastratus Mayr. Para ello, se excavaron dos nidos de cada especie y se recolectaron todos los individuos encontrados. Las tres especies tienen colonias pequeñas, compuestas por 300-1.100 individuos, de los cuales aproximadamente el 70% son obreras adultas. La estructura de sus nidos es relativamente simple, similar a la de la mayoría de las especies norteamericanas estudiadas, pero con un menor desarrollo en profundidad y un número menor de cámaras; probablemente se deba al menor número de obreras que poseen. Estas características (colonias pequeñas y nidos poco desarrollados son consideradas típicas para las especies del género Pogonomyrmex de América del Sur, lo que las diferencia de la mayoría de sus congéneres estudiados en América del Norte.Colony size in ants is associated with important ecological characteristics such as foraging strategy. Though colony size has been studied with some detail for several North American species of Pogonomyrmex harvester ants, it remains unknown for South American species. We studied colony size, composition, and nest structure of three species of Pogonomyrmex harvester ants inhabiting the central Monte desert in Argentina: P. mendozanus Cuezzo & Claver, P. inermis Forel and P. rastratus Mayr. We excavated two nests of each

  2. Composición florística de las etapas de sucesión primaria sobre afloramientos rocosos del Parque Nacional Natural El Tuparro, Colombia

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    Rojas Zamora Óscar Andrés

    2007-12-01

    Full Text Available En un afloramiento granítico del PNN El Tuparro, en Vichada, Colombia, se investigaron los cambios en
    diversidad y composición florística en el proceso de sucesión vegetal primaria. Se evaluaron cinco etapas
    de sucesión (rasante, herbácea, arbustiva, Bosquecito de Syagrus y Bosque de Attalea. En la sucesión a largo plazo, la diversidad y riqueza vegetal aumentan desde la etapa de criptógamas (iniciales hasta los Bosques de Attalea (tardías; al avanzar el proceso, se presenta igualmente un aumento en la complejidad estructural. Se presenta un desarrollo y reemplazo gradual de nuevos estratos vegetales desde los inicios de la sucesión hasta las etapas tardías. Se registraron 238 especies distribuidos en 72 familias. Para la etapa de Criptógamas se encontró en total de siete especies donde los más importantes por su cobertura son líquenes rupícolas y Eleocharis ayacuchensis, 45 especies distribuidos en 28 familias para la etapa herbácea destacándose Vellozia lithophila y especies de Pepinia, 108 especies distribuidos en 45 familias en la etapa arbustiva destacándose Tibouchina sp. Pepinia patentiflora y Tabebuia orinocensis, 104 especies distribuidos en 44 familias para el Monte de Syagrus con predominio de Syagrus inajai, Myrcianthes sp. y Tabebuia barbata, 83 especies distribuidos en 37 familias para el Bosque de Attalea donde se destaca A. regia, Anaueria sp. y Bactris sp. A lo largo de la sucesión se destacan especies del género Pepinia (Bromeliaceae, Vellozia lithophila, Plumeria inodora y lianas como Malouetia sp. y especies de Ipomoea debido a su alta capacidad de reproducción vegetativa constituyendo la línea de avanzada de los parches de vegetación sobre la roca. Los mayores índices de diversidad se registran en las etapas intermedias debido a la variedad de microambientes presentes en los parches, así como por el sobrelapamiento de especies de las etapas tempranas y tardías. Los resultados obtenidos

  3. Study of the heterogeneities effect in the dose distributions of Leksell Gamma Knife (R), through Monte Carlo simulation; Estudio del efecto de las heterogeneidades en las distribuciones de dosis del Leksell GammaKnife (R), mediante simulacion Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Rojas C, E.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Al-Dweri, F.M.O.; Lallena R, A.M. [Universidad de Granada, Granada (Spain)]. e-mail: elrc@nuclear.inin.mx

    2005-07-01

    In this work they are studied, by means of Monte Carlo simulation, the effects that take place in the dose profiles that are obtained with the Leksell Gamma Knife (R), when they are kept in account heterogeneities. The considered heterogeneities simulate the skull and the spaces of air that are in the head, like they can be the nasal breasts or the auditory conduits. The calculations were made using the Monte Carlo Penelope simulation code (v. 2003). The geometry of each one of the 201 sources that this instrument is composed, as well as of the corresponding channels of collimation of the Gamma Knife (R), it was described by means of a simplified model of geometry that has been recently studied. The obtained results when they are kept in mind the heterogeneities they present non worthless differences regarding those obtained when those are not considered. These differences are maximum in the proximities of the interfaces among different materials. (Author)

  4. Narrativas del pasado y literatura infantil: continuidades y rupturas en los planteos críticos de Graciela Montes y Ana Maria Machado

    Directory of Open Access Journals (Sweden)

    Laura Rafaela García

    2015-01-01

    Full Text Available Este trabajo propone continuar los estudios iniciados en otras instancias de investigación con el fin de explorar la literatura infanto - juvenil desde los estudios literarios y el impacto de la violencia política de las últimas dictaduras militares. El texto recorrerá l as miradas del pasado a partir de la experiencia de dos autoras claves para la literatura infantil de Argentina y de Brasil, como son Graciela Montes y Ana Maria Machado. Por un lado, este estudio pretende profundizar en los modos en los que la violencia p olítica de la última dictadura incidió en las prácticas intelectuales de estas autoras en los dos países. Esto nos permitirá establecer similitudes y diferencias entre ambos casos. Por otro lado, avanzaremos en el análisis de narrativas críticas entendidas como memorias fundamentales para la reconstrucción de las polémicas que definieron los principales planteos de la literatura para niños en los años noventa, dentro del contexto democrático. El posicionamiento crítico de las autoras con respecto a los movi mientos de su campo y las características del contexto de cada país contribuye a profundizar en los modos desde los cuales la literatura participa de la infancia.

  5. Evaluación del secuestro de carbono con diferentes alternativas de gestión selvícola en monte bajo de castaño en el Norte de España

    OpenAIRE

    Prada Monteagudo, Marta

    2014-01-01

    Las masas forestales y las actividades de manejo forestal juegan un papel importante en la fijación del carbono. Los objetivos del estudio fueron determinar la línea base de almacenamiento de carbono en monte bajo de castaño (Castanea sativa Mill.), evaluar el efecto de la gestión forestal y validar los resultados del modelo. El área de estudio se localiza en el norte de España. El modelo CO2FIX se utilizó para estimar el contenido de carbono en la biomasa, suelo y productos, evaluándose 5 al...

  6. Los depositos de yeso intrasedimentario del arroyo El Siasgo, partidos de Monte y General Paz, provincia de Buenos Aires

    Directory of Open Access Journals (Sweden)

    N. V. Dangavs

    2002-09-01

    Full Text Available El arroyo El Siasgo es un afluente del río Salado, situado en la región NE de la provincia de Buenos Aires. En su cuenca inferior, su curso recorta una gran depresión, remanente de una antigua cuenca de deflación colmatada, donde se desarrollaron, desde el Pleistoceno superior, diversos ambientes sedimentarios, principalmente acuáticos. Actualmente, se desarrolla, en esta depresión, un ambiente léntico temporario de 2.750 ha, dividido en dos cuerpos mediante un estrechamiento de la cubeta de 2 km de largo y 0,7 km de ancho. Al norte del estrechamiento se sitúa el cuerpo menor, denominado "La Cañada" y hacia el sur el mayor o "laguna del Siasgo". En los sedimentos clásticos hospedantes de este paleoambiente léntico múltiple aparece una importante acumulación de yeso intrasedimentario en distintos niveles estratigráficos (Formaciones Lobos, Luján y La Postrera I, cristalizado principalmente en tamaño arena, con diversidad de hábitos, texturas, fábricas y estructuras. Los sedimentos hospedantes del yeso son esencialmente fangos, cuya textura original se encuentra modificada por la presencia del mineral epigénico en fangos y limos arenosos e incluso en arenas fangosas. Este depósito yesífero abarca una superficie de 25,6 km², con un espesor medio de 2,15 m en el subambiente "del Siasgo" y de 0,91 m en "La Cañada". El volumen de sedimentos con yeso alcanza a 48 hm³ y la ley mineral mínima es 53,5% en la "laguna del Siasgo", con un total de 53.623.000 de toneladas de yeso impuro, mientras que en "La Cañada, con una ley media de 20,1 %, solamente alcanza a 1.361.000 toneladas de yeso impuro. Cabe señalar, que la baja ley del mineral en "La Cañada" descarta su aprovechamiento como recurso económico, mientras que el yeso presente en el subambiente "del Siasgo" es de alta potencialidad para su explotación, incluso en su valor mínimo. Estos yesos son el producto de la interacción de aguas superficiales y subterr

  7. Los equinodermos (Cystoidea. Homalozoa. Stelleroidea. Crinoidea del Paleozoico Inferior de los Montes de Toledo y Sierra Morena (España

    Directory of Open Access Journals (Sweden)

    Gutiérrez Marco, J. C.

    1984-12-01

    Full Text Available The presence of the cystoids Codiocystis and Phiyctocystis in the Llandeilo of Spain, associated to an undetermined Diploporite which may be a new genus, in confirmed. Several species of the genus Calix are described, some of them in open nomenclature, certain forms bearing a pentaradiated peristome. New samples of Homalozoa collected in the Middle Cambrian of Sierra Morena (Decacystis and the Lower Llanvirn of the Toledo Mountains (Mitrocystites are quotated, as well as an Asterozoa (Polaeura, found for the first time in Spain. The study of the echinoderm fauna collected in the "Tristani beds" (Llanvirn-Llandeilo of the Spanish Central-iberian zone allow to establish conclusions of biostratigraphic and paleobiogeographic interest.

    Se confirma la presencia de los cistideos Codlocystis y Phlyctocystis en el Llandeilo de España, junto a un Diploporito indeterminado que quizá corresponda a un nuevo género. Se describen diversas especies del género Calix, alguna de ellas en nomenclatura abierta, observándose en ciertas formas la existencia de un peristoma pentarradiado. Se citan nuevos ejemplares de Homalozoos procedentes del Cámbrico medio de Sierra Morena (Decocystls y del Llanvirn inferior de los Montes de Toledo (Mitrocystites, así como un Asterozoo, perteneciente al género Palaeura, descubierto por vez primera en España. El análisis de la fauna de equinodermos de las "capas con Tristani" (Llanvirn-Llandeilo de la zona Centro-ibérica española, perm ite, además, establecer diversas conclusiones de interés bioestratigráfico y paleobiogeográfico.

  8. Aplicación de tecnologías geoespaciales para la documentación del círculo lítico de Monte Lobeira, Vilanova de Arousa (Pontevedra

    Directory of Open Access Journals (Sweden)

    Mañana-Borrazás, Patricia

    2010-12-01

    Full Text Available In this work, we present a first approach to the stone circle of Monte Lobeira (in the NW of Spain. In this article we primarily focus on the methodologies that were applied in the documentation and register of the morphologic and constructive aspects of the site.

    En este trabajo pretendemos realizar una primera aproximación al círculo lítico de Monte Lobeira centrándonos fundamentalmente en las metodologías que se aplicaron en la documentación y registro de los aspectos morfológicos y constructivos del yacimiento.

  9. Circuitos del conocimiento: el Arte de la lengua índica de Valera y su inclusión en las polémicas sobre el Sacro Monte de Granada

    Directory of Open Access Journals (Sweden)

    José Alejandro Cárdenas Bunsen

    2014-07-01

    Full Text Available ResumenA partir del examen de documentos inéditos, este artículo muestra que Blas Valera (1545-1597 fue autor de un Arte de la lengua índica, que circulaba en Sevilla en 1595. Sostiene también que Valera puede ser identificado como el director detrás del Arte y vocabulario en la lengua general del Perú, publicado anónimamente en 1586. El estudio reconstruye, además, el contexto intelectual que hizo posible la circulación de la obra de Valera y los criterios filológicos que permitieron insertar su obra en las discusiones sobre las reliquias y libros del Sacro Monte de Granada y sus implicaciones sobre la historia de la iglesia primitiva española.Palabras clave: Blas Valera, Sacro Monte de Granada, Inca Garcilaso de la Vega, Tercer Concilio de LimaAbstractRelying on unpublished documents, this article maintains that Blas Valera (1545-1597 authored an unknown Arte de la lengua índica that circulated in Seville in 1595. It also argues that Valera can be identified as the single director behind the Arte y vocabulario en la lengua general del Perú that was published anonymously in 1586. In addition, this study reconstructs the intellectual milieu that made the circulation of Valera’s grammar possible and the philological criteria that laid the groundwork for its insertion in the debate regarding the relics and leaden books recently discovered at Granada’s Sacro Monte, and their implications for the history of Spain’s early Church.Keywords: Blas Valera, Sacro Monte de Granada, Inca Garcilaso de la Vega, Lima’s Third Council

  10. Paisajes del despojo cotidiano: acaparamiento de tierra y agua en Montes de María, Colombia

    Directory of Open Access Journals (Sweden)

    Diana Ojeda

    2015-10-01

    Full Text Available The phenomena of landgrabbing and monopolizing of water sources have gained increasing attention in recent years. Nevertheless, very few studies have dealt with the problem of the grabbing and concentration of resources from an ethnographic perspective that would make it possible to illustrate the different ways in which dispossession takes place, as well as its concrete mechanisms and effects in particular historical, geographic and political contexts. This article makes a critical contribution to the relevant literature. Based on the specific case of the area of Montes de María, located in the Caribbean region of Colombia, it shows how the violent forms of dispossession are produced and maintained by everyday dynamics. Through the analysis of i the imagined geographies of the region, ii the implementation of development projects, iii the processes of privatization of water resources, and iv the configuration of spaces of fear, this study illustrates how the landscapes of everyday dispossession in the region are produced. In this way, it seeks to contribute to the research on socio-environmental conflicts and to break into the narrative of post-conflict in the region.

  11. Volcano-estratigrafía y tectónica del Valle Central Occidentaly las estribaciones de los Montes del Aguacate a lo largo de la ruta 27, Costa Rica Volcano-stratigraphy and tectonics of the Western Central Valley and Montes del Aguacate along road 27, Costa Rica

    Directory of Open Access Journals (Sweden)

    Hernán Porras

    2012-12-01

    Full Text Available La Ruta 27, también conocida como carretera Ciudad Colón-Caldera, ofrece cortes geológicos de entre 5 y 40 m de altura que muestran una buena parte de la estratigrafía, en su mayoría volcánica y subvolcánica, del extremo occidental del Valle Central y las estribaciones de los Montes del Aguacate. Se observa una secuencia volcánica correlacionable con la Formación Grifo Alto (Plioceno, profundamente hidrotermalizada (alteración propilítica en varios sectores, compuesta por lavas, brechas y depósitos epivolcánicos, (depósitos fluviales de corrientes hiperconcentradas, depósitos de debris avalanches algunos ligera a moderadamente basculados, cortados por diques. Una serie de depósitos de debris avalanches antiguos también está presente, relacionados con el vulcanismo de los Montes del Aguacate. Localmente, una secuencia de varias unidades de mesobrechas de bloques andesíticos vidriosos, monomícticos en una matriz de cenizas vitro-cristalina, se interpreta como posibles depósitos asociados a flujos de bloques y cenizas, posiblemente en correspondencia con un vulcanismo coetáneo con la Formación Monteverde (Pleistoceno Inferior. Al menos 4 unidades de depósitos de debris flow/debris avalanche del Pleistoceno Medio se asocian a la Formación Nuestro Amo (Pleistoceno Medio. Sobre ellos se presentan los pórfidos andesíticos de la Formación Colima Inferior, seguidos de las ignimbritas de las formaciones Puente de Mulas y Tiribí, todas del Pleistoceno Medio, las que contienen niveles ignimbríticos hiperconcentrados e intercalaciones fluviales con espesores decrecientes. Un pliegue de propagación, que afecta a estas ignimbritas, es considerado indicio de la existencia de una tectónica de cabalgamiento de tipo piel delgada con vergencia al SW, activa al menos desde el Pleistoceno Medio. Gran parte del basculamiento de las rocas expuestas a lo largo de la Ruta 27, su tipo de fracturamiento, fallamiento y plegamiento, y la

  12. Beyond habitat structure: Landscape heterogeneity explains the monito del monte (Dromiciops gliroides) occurrence and behavior at habitats dominated by exotic trees.

    Science.gov (United States)

    Salazar, Daniela A; Fontúrbel, Francisco E

    2016-09-01

    Habitat structure determines species occurrence and behavior. However, human activities are altering natural habitat structure, potentially hampering native species due to the loss of nesting cavities, shelter or movement pathways. The South American temperate rainforest is experiencing an accelerated loss and degradation, compromising the persistence of many native species, and particularly of the monito del monte (Dromiciops gliroides Thomas, 1894), an arboreal marsupial that plays a key role as seed disperser. Aiming to compare 2 contrasting habitats (a native forest and a transformed habitat composed of abandoned Eucalyptus plantations and native understory vegetation), we assessed D. gliroides' occurrence using camera traps and measured several structural features (e.g. shrub and bamboo cover, deadwood presence, moss abundance) at 100 camera locations. Complementarily, we used radio telemetry to assess its spatial ecology, aiming to depict a more complete scenario. Moss abundance was the only significant variable explaining D. gliroides occurrence between habitats, and no structural variable explained its occurrence at the transformed habitat. There were no differences in home range, core area or inter-individual overlapping. In the transformed habitats, tracked individuals used native and Eucalyptus-associated vegetation types according to their abundance. Diurnal locations (and, hence, nesting sites) were located exclusively in native vegetation. The landscape heterogeneity resulting from the vicinity of native and Eucalyptus-associated vegetation likely explains D. gliroides occurrence better than the habitat structure itself, as it may be use Eucalyptus-associated vegetation for feeding purposes but depend on native vegetation for nesting.

  13. Analysis of the dead layer of a detector of germanium with code ultrapure Monte Carlo SWORD-GEANT; Analisis del dead layer de un detector de germanio ultrapuro con el codigo de Monte Carlo SWORDS-GEANT

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, S.; Querol, A.; Ortiz, J.; Rodenas, J.; Verdu, G.

    2014-07-01

    In this paper the use of Monte Carlo code SWORD-GEANT is proposed to simulate an ultra pure germanium detector High Purity Germanium detector (HPGe) detector ORTEC specifically GMX40P4, coaxial geometry. (Author)

  14. Paleoenvironmental reconstruction of the coastal Monte Léon and Santa Cruz formations (Early Miocene) at Rincón del Buque, Southern Patagonia: A revisited locality

    Science.gov (United States)

    Raigemborn, M. Sol; Matheos, Sergio D.; Krapovickas, Verónica; Vizcaíno, Sergio F.; Bargo, M. Susana; Kay, Richard F.; Fernicola, Juan C.; Zapata, Luciano

    2015-07-01

    Sedimentological, ichnological and paleontological analyses of the Early Miocene uppermost Monte León Formation and the lower part of the Santa Cruz Formation were carried out in Rincón del Buque (RDB), a fossiliferous locality north of Río Coyle in Santa Cruz Province, Patagonia, Argentina. This locality is of special importance because it contains the basal contact between the Monte Léon (MLF) and the Santa Cruz (SCF) formations and because it preserves a rich fossil assemblage of marine invertebrates and marine trace fossils, and terrestrial vertebrates and plants, which has not been extensively studied. A ˜90 m-thick section of the MLF and the SCF that crops out at RDB was selected for this study. Eleven facies associations (FA) are described, which are, from base to top: subtidal-intertidal deposits with Crassotrea orbignyi and bioturbation of the Skolithos-Cruziana ichnofacies (FA1); tidal creek deposits with terrestrial fossil mammals and Ophiomorpha isp. burrows (FA2); tidal flat deposits with Glossifungites ichnofacies (FA3); deposits of tidal channels (FA4) and tidal sand flats (FA5) both with and impoverish Skolithos ichnofacies associated; marsh deposits (FA6); tidal point bar deposits recording a depauperate mixture of both the Skolithos and Cruziana ichnofacies (FA7); fluvial channel deposits (FA8); fluvial point bar deposits (FA9); floodplain deposits (FA10); and pyroclastic and volcaniclastic deposits of the floodplain where terrestrial fossil mammal remains occur (FA11). The transition of the MLF-SCF at RDB reflects a changing depositional environment from the outer part of an estuary (FA1) through the central (FA2-6) to inner part of a tide-dominated estuary (FA7). Finally a fluvial system occurs with single channels of relatively low energy and low sinuosity enclosed by a broad, low-energy floodplain dominated by partially edaphized ash-fall, sheet-flood, and overbank deposits (FA8-11). Pyroclastic and volcaniclastic materials throughout the

  15. The Capilla del Monte pluton, Sierras de Córdoba, Argentina: the easternmost Early Carboniferous magmatism in the pre-Andean SW Gondwana margin

    Science.gov (United States)

    Dahlquist, Juan A.; Pankhurst, Robert J.; Rapela, Carlos W.; Basei, Miguel A. S.; Alasino, Pablo H.; Saavedra, Julio; Baldo, Edgardo G.; Murra, Juan A.; da Costa Campos Neto, Mario

    2016-07-01

    New geochronological, geochemical, and isotopic data are reported for the Capilla del Monte two-mica granite pluton in the northeastern Sierras de Córdoba. An Early Carboniferous age is established by a U-Pb zircon concordia (336 ± 3 Ma) and a Rb-Sr whole-rock isochron (337 ± 2 Ma). Zircon saturation geothermometry indicates relatively high temperatures (735-800 °C). The granites have high average SiO2 (74.2 %), Na2O + K2O (7.8 %), and high field-strength elements, high K2O/Na2O (1.7) and FeO/MgO ratios (5.1), with low CaO content (0.71 %). REE patterns with marked negative Eu anomalies (Eu/Eu* 0.14-0.56) indicate crystal fractionation, dominantly of plagioclase and K-feldspar, from a peraluminous magma enriched in F. Isotope data (87Sr/86Srinitial = 0.7086, ɛ Nd336 = -5.5 to -4.4 with T DM = 1.5 Ga, zircon ɛ Hf336 +0.8 to -6.1; mean T DM = 1.5 Ga) suggest a Mesoproterozoic continental source, albeit with some younger or more juvenile material indicated by the Hf data. The pluton is the easternmost member of a Carboniferous A-type magmatic suite which shows an increase in juvenile input toward the west in this part of the pre-Andean margin. The petrological and geochemical data strongly suggest a similar intraplate geodynamic setting to that of the nearby but much larger, Late Devonian, Achala batholith, although Hf isotope signatures of zircon suggest a more uniformly crustal origin for the latter. Further studies are required to understand whether these bodies represent two independent magmatic episodes or more continuous activity.

  16. Body mass variation in the Geoffroy's cat (Oncifelis geoffroyi Variaciones de la masa corporal del gato montés (Oncifelis geoffroyi

    Directory of Open Access Journals (Sweden)

    MAURO LUCHERINI

    2006-06-01

    Full Text Available We report new data on the intersexual and geographical variation in body mass of the Geoffroy's cat (Oncifelis geoffroyi d'Orbigny and Gervais 1844, a little known small cat from South America, and combine them with the existing information to compare alternative hypotheses for variation in body mass. Most data on the body mass of O. geoffroyi have been obtained from previous research on this felid in four study areas of southern Brazil and central and southern Argentina. These data were added to those reported for other three additional locations. Our results set the body mass of O. geoffroyi to 4.26 ± 1.03 kg (mean ± SD, n = 56. We also show that males generally are heavier than females throughout most of this species' distributional range. Body mass dimorphism is 1.34 on average, but ranges from 1.19 and 1.21 in Uruguay and southern Chile, respectively, to 1.76 in the northern Pampas of Argentina. When data from the best sampled areas are considered (Torres del Paine, Lihué Calel, southern Pampas, Campos del Tuyú and southern Brazil, only male body mass varies with geographic location. More intriguingly, no correlation was found between body mass and latitude. Our results suggest a smaller mean weight of O. geoffroyi relative to what was previously published, but also suggest a wider variation. Our analysis do not support Bergmann's rule, according to which the largest individuals would occur in the southernmost regions of this cat's geographic distribution, while they seem supportive of a sexually-selected process affecting sexual size dimorphism in the Geoffroy's catSe reportan nuevos datos sobre la variación intersexual y geográfica de la masa corporal en el gato montés (Oncifelis geoffroyi d'Orbigny and Gervais 1844, un félido pequeño y poco conocido de América del Sur, y los combinamos con la información existente para evaluar dos hipótesis que explicarían esta variación. La mayor parte de los datos sobre masa corporal de O

  17. Dosimetric effect of statistics noise of the TC image in the simulation Monte Carlo of radiotherapy treatments; Efecto dosimetrico del ruido estadistico de la imagen TC en la simulacion Monte Carlo de tratamientos de radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Laliena Bielsa, V.; Jimenez Albericio, F. J.; Gandia Martinez, A.; Font Gomez, J. A.; Mengual Gil, M. A.; Andres Redondo, M. M.

    2013-07-01

    The source of uncertainty is not exclusive of the Monte Carlo method, but it will be present in any algorithm which takes into account the correction for heterogeneity. Although we hope that the uncertainty described above is small, the objective of this work is to try to quantify depending on the CT study. (Author)

  18. Depreciación de la plata, políticas públicas y desarrollo empresarial. Las pequeñas y medianas empresas mineras mexicanas de Pachuca y Real del Monte

    Directory of Open Access Journals (Sweden)

    Uribe Salas, José Alfredo

    2011-08-01

    Full Text Available This article studies the business strategies and capacity of small and medium-sized mining enterprises that operated in the Pachuca-Real del Monte mining district in Mexico in the late 19th century. In a regional economic context dominated by the monopoly of the Compañía de Minas Real del Monte y Pachuca, small and medium-sized enterprises managed to obtain advantages from both the silver depreciation in the international currency markets and the Mexican public policies focused precisely on mitigating the fall in the price of silver after 1873. The way that some minor and medium-sized local entrepreneurs injected new life into mining activities in the region, thereby actually benefiting from the international circumstances, is analysed. In sum, it was the small and medium-sized mining companies that supported the productive and business development that characterized the period of mining growth in the district during the dictatorship of President Porfirio Díaz.

    Se estudian las estrategias empresariales y la capacidad de las pequeñas y medianas empresas mineras que operaron en el Distrito de Real del Monte y Pachuca para obtener ventajas relativas tanto de la depreciación de la plata en los mercados internacionales como de las políticas públicas establecidas por los gobiernos mexicanos después de 1873 para paliar la caída del valor argentífero, en un contexto de monopolio minero-metalúrgico promovido por la Compañía de Minas Pachuca y Real del Monte. Se analiza cómo algunos pequeños y medianos empresarios locales dieron nuevos bríos a la actividad minera y cómo se vieron beneficiados con la situación internacional. Se concluye que fueron las pequeñas y medianas empresas las que sustentaron el desarrollo productivo y empresarial que caracterizó el auge minero en la región de estudio durante periodo porfirista en México.

  19. Estado ecológico de los ríos incluidos dentro del parque Nacional de Ordesa y Monte Perdido (Cuenca del Ebro, Aragón, mediante indicadores de macroinvertebrados

    Directory of Open Access Journals (Sweden)

    Valladolid, María

    2015-12-01

    Full Text Available We provide information about the ecological status of Arazas, Bellós and Yaga rivers (Ordesa y Monte Perdido National Park, obtained from samples collected by volunteers during the 2013 spring-summer season, included in the “Volunteering activities in the Parks Network” program (MAGRAMA. In each river three points have been selected, all belonging to Type 27: High mountain rivers, except one that is Type 26: Humid calcareous mountain river. For each point several macroinvertebrate indexes (IBMWP, IASPT, NFAM, NFPLE and EPT and their ecological quality ratios (EQR were calculated. As a whole, 72% of the IBMWP measurements show Very good or Good quality, a 22% Moderate and a 6% Deficient. The Yaga River showed all the measures as Very Good-Good while in the Arazas River we found the three classes of quality cited. In general, for each river the values of the indexes are decreasing from mouth to source, while most of values are increasing in a temporal pattern (from spring to late summer in each sampling point, except in two points, Arazas-3 and Bellós-2, that show the opposite pattern.Se presenta información sobre el estado ecológico de los ríos Arazas, Bellós y Yaga (Parque Nacional de Ordesa y Monte Perdido, obtenida a partir de muestras recolectadas en la primavera-verano de 2013 por voluntarios, dentro del programa “Actividades de voluntariado en la Red de Parques” (MAGRAMA. En cada río se seleccionaron tres puntos de muestreo, todos pertenecientes al Tipo 27: Ríos de alta montaña, excepto uno, del Tipo 26: Ríos de montaña húmeda calcárea. Para cada punto se ha calculado una serie de índices de macroinvertebrados (IBMWP, IASPT, NFAM, NFPLE y EPT y sus ratios de estado ecológico (EQR. En total, el 72% de las medidas del IBMWP dan una calidad Muy buena o Buena, un 22% Moderada y un 6% Deficiente. El río Yaga presentó todas las medidas de calidad Muy Buena-Buena, mientras que en el río Arazas encontramos las tres clases

  20. Gestire il denaro, gestire la salvezza. Tre immagini a sostegno del Monte di Pietà: Marco da Montegallo, Lorenzo d’Alessandro e Vittore Crivelli / Managing money, managing salvation. Three images in support of the Mont of Piety: Marco da Montegallo, Lorenzo d’Alessandro and Vittore Crivelli

    Directory of Open Access Journals (Sweden)

    Giuseppe Capriotti

    2011-12-01

    Full Text Available I francescani dell’Osservanza, attraverso le prediche sulla mercatura, sull’usura e sulla carità, promuovono un tipo d’economia, strettamente connessa al mercato e all’affidabilità imprenditoriale del mercante, il quale deve essere in grado di far circolare fruttuosamente il denaro e poi di investire parte dei suoi introiti in opere caritatevoli o di pubblica utilità, in funzione della sua salvezza. Non di rado tali investimenti si concretizzano nella commissione di immagini, spesso esposte proprio in chiese francescane, o nel sostentamento del Monte di Pietà, un’istituzione bancaria, inventata e difesa dagli osservanti, che, spesso in rivalità col banco ebraico, prestava denaro su pegno. La promozione e la legittimazione di questo istituto, che sin dalla sua nascita genera numerose dispute, anche interne allo stesso ordine francescano, soprattutto per quel che riguarda la liceità o meno dell’interesse, è affidata non solo alle prediche, ma anche alle opere d’arte. Nella Marca appenninica di fine Quattrocento sono state prodotte a tale scopo almeno tre immagini. Simili nel contenuto e nella tipologia, la Figura della vita eterna, ideata dal predicatore osservante Marco da Montegallo, la Madonna del Monte di Caldarola, dipinta dal sanseverinate Lorenzo d’Alessandro, e l’omologa Madonna del Monte di Massa Fermana, realizzata da Vittore Crivelli, si illuminano e si chiariscono a vicenda. The Franciscans of the Osservanza order, through their sermons on commerce, usuryand charity, promote a type of economy, that is closely related to the business market andto the reliability of the merchant, who must be able to make money circulate fruitfully and then to invest part of his benefits on good deeds or public works, to have salvation.These investments are often used in the commission of images, often exposed in Franciscan churches, or in support of the Mont of Piety, a bank, developed and defended by the Osservanti, that, often

  1. Notas sobre a composição arbóreo-arbustiva de uma fisionomia das savanas de Roraima, Amazônia Brasileira Notes on the woody composition of a vegetation physionomy of the Roraima's savannas, Brazilian Amazonia

    Directory of Open Access Journals (Sweden)

    Reinaldo Imbrozio Barbosa

    2005-06-01

    Full Text Available Foi realizado um inventário florístico das espécies arbóreo-arbustivas presentes em uma das unidades de vegetação que compõem a paisagem de savanas do Estado de Roraima, extremo norte da Amazônia brasileira. Esta unidade é caracterizada por ser densamente colonizada por ninhos do cupim Cornitermes ovatus Emerson. Foram observadas 29 espécies (15 famílias botânicas em três localidades utilizadas para a amostragem. O total de espécies, por localidade, variou de 12 a 20. As espécies mais abundantes foram Byrsonima verbascifolia (L. DC. e Mimosa microcephala Humb. & Bonpl. ex Willd. (subarbustivas, Byrsonima cf. intermedia A. Juss. e Randia formosa (Jack. K. Schum. (arbustivas e, Byrsonima crassifolia (L. H.B.K. e Curatella americana L. (arbóreas. Oito espécies são comuns às três localidades. A diversidade medida pelo Índice de Shannon (H' foi baixa para todos os locais amostrados (A floristic inventory of woody species was carried out in one of the vegetation units that compose the savannas landscape of the Roraima State, northernmost of Brazilian Amazonia. This unit is characterized by dense colonization of nests of termites Cornitermes ovatus Emerson. Twenty nine woody species were observed (15 botany families in three localities used for sampling. The total of species varied from 12 to 20 by locality. The most abundant species were Byrsonima verbascifolia (L. DC. and Mimosa microcephala Humb. & Bonpl. ex Willd. (dwarf shrubs, Byrsonima cf. intermedia A. Juss. and Randia formosa (Jack. K. Schum. (shrubby and, Byrsonima crassifolia (L. H.B.K. and Curatella americana L. (arboreal. Eight species are common to all localities. Diversity measured by the Index of Shannon (H' was low for all the areas sampled (<0.90 indicating high specimens concentration in few species. The Index of Sørensen indicated similarities (± 0.60 among studied areas, suggesting a group of landscapes with common plant diversity, representing a same

  2. Retrospective study of the calculation of doses by Monte Carlo in extracranial stereotactic; Estudio retrospectivo del calculo de dosis mediante Monte Carlo en radioterapia estereotaxica extracraneal (SBRT) de pulmon

    Energy Technology Data Exchange (ETDEWEB)

    Zucca Aparicio, D.; Perez Moreno, J. M.; Fernandez Leton, P.; Garcia Ruiz-Zorrilla, J.; Minambres Moro, A.

    2013-07-01

    The objective of this work consists of the evaluation of those clinical parameters described in RTOG 0813 and 0915 RTOG protocols relevant applicable to PTV, lung tissue and healthy normal, of those patients treated in our institution since April 2008, calculated initially through Pencil Beam and recalculated currently using Monte Carlo is interesting remark that the RTOG 0813 Protocol replaces the previous RTOG 0236 which expressly mentioned do not make corrections by heterogeneity in the calculation of dose in lung lesions. (Author)

  3. Monte Carlo techniques for the study of cancer patients fractionation in head and neck treated with radiotherapy; Tecnicas de Monte Carlo para el estudio del fraccionamiento en pacientes de cancer de cabeza y cuello tratados con radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco Herrera, M. A.; Jimenez Dominguez, M.; Perucha Ortega, M.; Herrador Cordoba, M.

    2011-07-01

    The dose fractionation than the standard head and neck cancer in some situations involve a significant increase of local control and overall survival. There is clinical evidence of these results in case of hyperfractionated treatments, although the choice of optimal fractionation generally is not obtained from the results of any model, in this study has provided the tumor control probability (TCP) for various subdivisions modified (hypo fractionated and hyperfractionated) using Monte Carlo simulation techniques.

  4. Calibration of the identiFINDER detector for the iodine measurement in thyroid using the Monte Carlo method; Calibracion del detector identiFINDER para la medicion de yodo en tiroides utilizando el metodo Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Ramos M, D.; Yera S, Y.; Lopez B, G. M.; Acosta R, N.; Vergara G, A., E-mail: dayana@cphr.edu.cu [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/ 41 y 47, Playa, 10600 La Habana (Cuba)

    2014-08-15

    This work is based on the determination of the detection efficiency of {sup 125}I and {sup 131}I in thyroid of the identiFINDER detector using the Monte Carlo method. The suitability of the calibration method is analyzed, when comparing the results of the direct Monte Carlo method with the corrected, choosing the latter because the differences with the real efficiency stayed below 10%. To simulate the detector their geometric parameters were optimized using a tomographic study, what allowed the uncertainties minimization of the estimates. Finally were obtained the simulations of the detector geometry-point source to find the correction factors to 5 cm, 15 cm and 25 cm, and those corresponding to the detector-simulator arrangement for the method validation and final calculation of the efficiency, demonstrating that in the Monte Carlo method implementation if simulates at a greater distance than the used in the Laboratory measurements an efficiency overestimation can be obtained, while if simulates at a shorter distance this will be underestimated, so should be simulated at the same distance to which will be measured in the reality. Also, is achieved the obtaining of the efficiency curves and minimum detectable activity for the measurement of {sup 131}I and {sup 125}I. In general is achieved the implementation of the Monte Carlo methodology for the identiFINDER calibration with the purpose of estimating the measured activity of iodine in thyroid. This method represents an ideal way to replace the lack of patterns solutions and simulators assuring the capacities of the Internal Contamination Laboratory of the Centro de Proteccion e Higiene de las Radiaciones are always calibrated for the iodine measurement in thyroid. (author)

  5. Florística del bosque mesófilo de montaña de Monte Grande, Lolotla, Hidalgo, México Floristics of the cloud forest of Monte Grande, Lolotla, Hidalgo, Mexico

    OpenAIRE

    2006-01-01

    Se presenta un estudio florístico del bosque mesófilo de montaña del municipio de Lolotla, localizado al noreste del estado de Hidalgo. El área está enclavada en la Sierra Madre Oriental, dentro de la región de la Huasteca hidalguense. Se ofrece un listado florístico de las plantas vasculares, compuesto por 103 familias, 260 géneros, 359 especies y 11 taxa subespecíficos. En este bosque hay 11 especies que están en alguna categoría de riesgo dentro de la Norma Oficial Mexicana NOM-050-ECOL-20...

  6. Los depositos de yeso intrasedimentario del arroyo El Siasgo, partidos de Monte y General Paz, provincia de Buenos Aires Intrasedimentary gypsum deposits of El Siasgo Creek, Monte and General Paz districts, Buenos Aires Province

    Directory of Open Access Journals (Sweden)

    N. V. Dangavs

    2002-09-01

    Full Text Available El arroyo El Siasgo es un afluente del río Salado, situado en la región NE de la provincia de Buenos Aires. En su cuenca inferior, su curso recorta una gran depresión, remanente de una antigua cuenca de deflación colmatada, donde se desarrollaron, desde el Pleistoceno superior, diversos ambientes sedimentarios, principalmente acuáticos. Actualmente, se desarrolla, en esta depresión, un ambiente léntico temporario de 2.750 ha, dividido en dos cuerpos mediante un estrechamiento de la cubeta de 2 km de largo y 0,7 km de ancho. Al norte del estrechamiento se sitúa el cuerpo menor, denominado "La Cañada" y hacia el sur el mayor o "laguna del Siasgo". En los sedimentos clásticos hospedantes de este paleoambiente léntico múltiple aparece una importante acumulación de yeso intrasedimentario en distintos niveles estratigráficos (Formaciones Lobos, Luján y La Postrera I, cristalizado principalmente en tamaño arena, con diversidad de hábitos, texturas, fábricas y estructuras. Los sedimentos hospedantes del yeso son esencialmente fangos, cuya textura original se encuentra modificada por la presencia del mineral epigénico en fangos y limos arenosos e incluso en arenas fangosas. Este depósito yesífero abarca una superficie de 25,6 km², con un espesor medio de 2,15 m en el subambiente "del Siasgo" y de 0,91 m en "La Cañada". El volumen de sedimentos con yeso alcanza a 48 hm³ y la ley mineral mínima es 53,5% en la "laguna del Siasgo", con un total de 53.623.000 de toneladas de yeso impuro, mientras que en "La Cañada, con una ley media de 20,1 %, solamente alcanza a 1.361.000 toneladas de yeso impuro. Cabe señalar, que la baja ley del mineral en "La Cañada" descarta su aprovechamiento como recurso económico, mientras que el yeso presente en el subambiente "del Siasgo" es de alta potencialidad para su explotación, incluso en su valor mínimo. Estos yesos son el producto de la interacción de aguas superficiales y subterr

  7. Florística del bosque mesófilo de montaña de Monte Grande, Lolotla, Hidalgo, México Floristics of the cloud forest of Monte Grande, Lolotla, Hidalgo, Mexico

    Directory of Open Access Journals (Sweden)

    Armando Ponce-Vargas

    2006-12-01

    Full Text Available Se presenta un estudio florístico del bosque mesófilo de montaña del municipio de Lolotla, localizado al noreste del estado de Hidalgo. El área está enclavada en la Sierra Madre Oriental, dentro de la región de la Huasteca hidalguense. Se ofrece un listado florístico de las plantas vasculares, compuesto por 103 familias, 260 géneros, 359 especies y 11 taxa subespecíficos. En este bosque hay 11 especies que están en alguna categoría de riesgo dentro de la Norma Oficial Mexicana NOM-050-ECOL-2001 y se sugiere el estudio de dos más para su posible inclusión.A floristic inventory of the cloud forest of the municipality of Lolotla, in the state of Hidalgo was undertaken; this area is located in the Sierra Madre Oriental and is part of the Huasteca Hidalguense region. A floristic checklist of vascular plants composed by 103 families, 260 genera, 359 species and 11 subspecific taxa was obtained. Eleven species represented in this forest are included in the official Mexican document named Norma Oficial Mexicana NOM-050-ECOL-2001, as species in some risk category and we suggest the study of two additional species for their possible inclusion.

  8. El arzobispo don Pedro de Castro Cabeza de Vaca y Quiñones y la influencia del Sacro Monte en el desarrollo inmaculista en Granada.

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    José Antonio Peinado Guzmán

    2015-12-01

    Full Text Available The figure of archbishop don Pedro de Castro was extremely important for the development of immaculist devotion in Granada in the 16th century and beginning of the 17th century. In the wake of the famous discoveries of the Sacro Monte, it will produce an evolution of this belief in land Granada at the request of this prelate, who took the issue as one of his personal priorities in his episcopate. Intelligent handling of the issue by the Archbishop, while the findings of the Sacro Monte were subsequently convicted of Rome, eventually landing in the erection of the Abbey, in the ideological use of all of this, as well as the extension of the conceptionism in Granada.

  9. Use of Monte Carlo simulation software for the calculation of the effective dose in cone beam Tomography; Uso del software de simulacion Monte Carlo para el calculo de la dosis efectiva en Tomografia de haz conico

    Energy Technology Data Exchange (ETDEWEB)

    Gomes B, W. O., E-mail: wilsonottobatista@gmail.com [Instituto Federal da Bahia, Rua Emidio dos Santos s/n, Bardalho, 40301-015 Salvador, Bahia (Brazil)

    2015-10-15

    Full text: In this study irradiation geometry applicable to PCXMC and the consequent calculation of effective dose in applications of cone beam computed tomography (CBCT) was developed. Two different CBCT equipment s for dental applications were evaluated: Care Stream Cs-9000 3-Dimensional and Gendex GXCB-500 tomographs. Each protocol initially was characterized by measuring the surface kerma input and the product air kerma-area, P{sub KA}. Then, technical parameters of each of the predetermined protocols and geometric conditions in the PCXMC software were introduced to obtain the values of effective dose. The calculated effective dose is within the range of 9.0 to 15.7 μSv for Cs 9000 3-D and in the range 44.5 to 89 mSv for GXCB-500 equipment. These values were compared with dosimetric results obtained using thermoluminescent dosimeters implanted in anthropomorphic mannequin and were considered consistent. The effective dose results are very sensitive to the radiation geometry (beam position); this represents a factor of fragility software usage, but on the other hand, turns out to be a very useful tool for quick conclusions regarding the optimization process of protocols. We can conclude that the use of Monte Carlo simulation software PCXMC is useful in the evaluation of test protocols of CBCT in dental applications. (Author)

  10. Referencias documentales en torno a la dotación artística primigenia de la abadía del Sacro Monte en Granada = References documentaries around the primitive artistic endowment of the abbey of the Sacro Monte in Granada

    Directory of Open Access Journals (Sweden)

    Palomino Ruiz, Isaac

    2016-09-01

    Full Text Available Resumen: Una de las instituciones históricas con más solera en la ciudad de Granada es, sin lugar a dudas, la Abadía del Sacro Monte. Configurada como un centro religioso, académico, cultural y artístico, ha ejercido una enorme influencia a lo largo de los siglos en la sociedad granadina. El presente artículo pretende indagar en los comienzos de este lugar, concretamente en la dotación artística de sus inicios, gracias a la ingente donación de su fundador, don Pedro de Castro Cabeza de Vaca y Quiñones. = Abstract: Historical institutions with more tradition in the city of Granada is, without a doubt, the Abbey of the Sacro Monte. Configured as a religious center, academic, cultural and artistic, has exercised an enormous influence over the centuries in the Granada society. This article aims to explore the beginnings of this place, specifically in the artistic endowment of its inception, thanks to the huge donation of its founder, don Pedro de Castro Cabeza de Vaca y Quiñones.

  11. Estudio de la composición, disponibilidad y calidad de los recursos apícolas del noroeste de La Pampa, Provincia Fitogrográfica del Monte (República Argentina)

    OpenAIRE

    Tamame, María Angélica

    2011-01-01

    Las abejas melíferas se alimentan fundamentalmente del polen y del néctar disponible en una región, estos elementos permiten el normal desarrollo de la colonia. Mediante la identificación del polen presente en las cargas corbiculares y en las mieles que producen las abejas es posible detectar los recursos poliníferos y nectaríferos de una región. El estudio del contenido proteico del polen y de algunos parámetros físicoquímicos de las mieles permite detectar la calidad de ambos prod...

  12. Estudio de la composición, disponibilidad y calidad de los recursos apícolas del noroeste de La Pampa, Provincia Fitogrográfica del Monte (República Argentina)

    OpenAIRE

    Tamame, María Angélica

    2011-01-01

    Las abejas melíferas se alimentan fundamentalmente del polen y del néctar disponible en una región, estos elementos permiten el normal desarrollo de la colonia. Mediante la identificación del polen presente en las cargas corbiculares y en las mieles que producen las abejas es posible detectar los recursos poliníferos y nectaríferos de una región. El estudio del contenido proteico del polen y de algunos parámetros físicoquímicos de las mieles permite detectar la calidad de ambos productos. ...

  13. Propuesta de un sistema de indicadores para evaluar el impacto del turismo en la pobreza de la localidad de Monte Hermoso

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    Silvina Elías

    2012-11-01

    Full Text Available Este trabajo plantea un sistema de indicadores de la actividad turística en la localidad de Monte Hermoso (Provincia de Buenos Aires, República Argentina basado en el modelo DPSIR (Driving Forces, Pressures, States, Impacts and Responses. Las limitaciones propias de este modelo, así como aquellas referidas a la información disponible presentan algunas dificultades. Sin embargo, avanzar en su implementación permitirá tomar acciones de política que se orienten a la disminución de la pobreza en la citada localidad, generando igualdad de oportunidades para todos los actores involucrados.

  14. Sísmica de reflexión de alta resolución en el estudio del Cuaternario de áreas de pie de monte

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    G. González Bonorino

    2003-03-01

    Full Text Available Se realizaron varias pruebas piloto con sísmica de reflexión de baja profundidad en depósitos de abanicos aluviales distales en la provincia de Salta, Argentina. Las pruebas incluyen dos áreas con características de subsuelo contrastantes. En el sector nororiental de la provincia, los depósitos del extenso abanico aluvial del Bermejo son arenosos y macizos, casi sin intercalaciones arcillosas; la napa se encontraba a más de 40 m de profundidad al tiempo del estudio. La otra zona de prueba se ubica al sur de la ciudad de Salta, donde coalescen abanicos aluviales pequeños que rellenan el valle de Lerma con depósitos de arena y grava, los cuales en los tramos distales se interdigitan con potentes capas arcillosas; la napa en esta área se hallaba a una profundidad mayor de 20 m al momento del estudio. La operación sísmica empleó un sismógrafo Geometrics R24 con 24 canales activos que se aumentaron a 48 mediante un "roll-over switch", alcanzando un máximo de cobertura de 1200%. Se probaron dos fuentes de sonido: una masa de 5 kg y una escopeta calibre 12. Principalmente por razones operativas se eligió como fuente la masa. Las pruebas en el abanico del Bermejo dieron registros de baja calidad, probablemente debido a la rápida pérdida de energía en las areas poco consolidadas y secas. Localmente, sin embargo, pudieron distinguirse tres unidades sísmicas y el techo del Terciario posiblemente fue detectado. Las pruebas en eje del valle de Lerma dieron registros sísmicos de excelente calidad. Se distinguieron cuatro unidades sísmicas. Un reflector débil a aproximadamente 220 mseg coincide con un cambio de las velocidades a unos 2500 m/seg y puede corresponder con el techo del sustrato terciario. Una potente capa de arcilla a una profundidad de 25 a 50 m puede claramente mapearse como un acuitardo. Los resultados de este estudio piloto demuestran que la sísmica de reflexión de poca profundidad puede ser aplicada con provecho en el

  15. ¿''Globalización sostenible''? Desarrollo sostenible como pegamento para el montón de cristales trizados del neoliberalismo

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    Brand Ulrich

    2003-01-01

    Full Text Available En la Cumbre Mundial sobre Medio Ambiente y Desarrollo en Johannesburgo a mediados del año 2002, se pudo ver claramente que los entendimientos y las prácticas del desarrollo sostenible están en un callejón sin salida. Eso tiene que ver con el hecho que se habían ignorado los procesos mucho más dinámicos de la globalización neoliberal y de la reestructuración del mundo, incluyendo la nueva legitimidad de las guerras en los años 90s. Después del 11 de septiembre del año 2001, argumentan los autores, se hizo evidente que vivimos en una situación no hegemónica con implicaciones específicas. Pero el ''desarrollo sostenible'' no se fracturó como contra discurso. Al contrario, sus orientaciones y prácticas eran cada vez más compatibles con la reestructuración dominante. El desarrollo sostenible perdió sus implicaciones críticas con su enfoque en la cooperación y el conocimiento moderno occidental, su conceptualización tecnócrata de la política, la predominancia de las cuestiones medioambientales sobre las del desarrollo y el Estado-nación como área privilegiada para la implementación de políticas. Además, las instituciones internacionales del desarrollo sostenible (en el artículo se toma como ejemplo del Convenio sobre Diversidad Biológica son parte de la economización de la naturaleza. Finalmente, en el último tiempo ganaron legitimidad las iniciativas que intentan establecer mecanismos militares en países del Sur que se justifican con la necesidad de políticas de desarrollo sostenible. Actualmente, el ''proceso de Río'' trata de reconciliar los procesos de globalización con el desarrollo sostenible y, eventualmente, el término ''globalización sostenible'' va a surgir como nuevo paradigma para las orientaciones y prácticas dominantes. Al final del artículo, los autores argumentan que los desafíos más dinámicos contra la globalización neoliberal y la militarización emergen en otro terreno político que

  16. Evaluación del espesor de capas delgadas mediante análisis EDS y simulación de Monte Carlo

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    García, J. C.

    2010-12-01

    Full Text Available This work shows a method to evaluate the thin layer thickness by the X ray dispersive energy (EDS technique. The analytical measures of the area of characteristic peaks carried out with this technique are complemented with electron trajectories on the interaction volume byMonte Carlo simulation. These together with the estimations obtained for the characteristic peaks intensities according to Bethe, Joy&Luo algorithm makes possible to estimate the thickness of samples.En este trabajo se presenta un método de evaluación de espesores de capas delgadas mediante la técnica de energías dispersivas de rayos X (EDS. Las medidas analíticas de las áreas de los picos característicos de los elementos detectados en las capas, obtenidas mediante esta técnica, se complementan con simulaciones de Monte Carlo de las trayectorias de los electrones en el volumen de interacción. Esto, junto con las estimaciones de la intensidad de los picos característicos obtenidos mediante el algoritmo de Bethe, Joy & Luo, posibilita realizar la estimación de los espesores de las muestras analizadas.

  17. Efecto del medioambiente sobre la biología reproductiva de dos especies de aves insectívoras forestales en los Montes de Toledo

    OpenAIRE

    Bueno Enciso, Javier

    2016-01-01

    El fenotipo de las poblaciones animales que observamos está altamente influenciado por las condiciones del medio ambiente donde dichas poblaciones viven. Por lo tanto, para entender en profundidad las características de una población es necesario saber las presiones del medio ambiente que dicha población está soportando. Conocer el papel que el medio ambiente tiene sobre el fenotipo de los individuos que componen una población no es sólo importante a nivel de investigación básica, si no que r...

  18. Abiotic gradients drive floristic composition and structure of plant communities in the Monte Desert Gradientes abióticos dirigen la composición florística y la estructura de las comunidades de plantas en el Desierto del Monte

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    PABLO ACEBES

    2010-01-01

    Full Text Available Defining plant communities in desert zones is difficult due to large scale homogeneity and small scale heterogeneity, thus making provision of systematic information for conservation decisions problematic. We analysed plant communities of the most arid sector of Monte Desert for structure, plant composition and environmental variables. Small-scale variables such as slope, rock cover, bare ground and litter, as well as large-scale ones such as species diversity, composition and similarity within and between sites were included. Analyses of floristic composition showed the difficulty of segregating distinct communities due to high internal heterogeneity and overlap between the different sites. Only mesquite woodlands, a community situated at the extreme of the soil moisture-gradient was segregated. Ordination on structural variables was somewhat more successful in segregating communities on the basis of substrate type and of tree and shrub cover. Our results showed the difficulty distinguishing plant communities in temperate deserts, suggesting the existence of relatively stable assemblages of species at the extremes of the gradients and of great heterogeneity within and between sites. They cannot be defined by floristic variables solely, but require environmental information also.La definición de comunidades discretas de plantas en zonas desérticas es complejo debido tanto a su homogeneidad a gran escala como a su heterogeneidad a pequeña escala, lo que acaba generando dificultades para la toma de decisiones de conservación. En este trabajo analizamos las comunidades de plantas del sector más árido del Desierto del Monte en función de su estructura y composición florística. Se han utilizado también variables ambientales estimadas a pequeña escala como la pendiente o la superficie de roca, suelo desnudo y hojarasca, así como variables que operan a mayor escala como la diversidad de especies, la composición florística y la similitud

  19. Estoque de serapilheira e fertilidade do solo em pastagem degradada de Brachiaria decumbens após implantação de leguminosas arbustivas e arbóreas forrageiras

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    André Barbosa Silva

    2013-04-01

    Full Text Available As pastagens formam a base da pecuária brasileira; essas sofrem degradação em larga escala por deficiência de nitrogênio (N. O consórcio com leguminosas, além de fixar N, pode apresentar outros efeitos na fertilidade do solo como acidificação ou retirada de nutrientes de camadas mais profundas para as mais superficiais. Este trabalho objetivou avaliar o estoque de serapilheira e a fertilidade do solo em pastagens degradadas de braquiária (Brachiaria decumbens, após implantar leguminosas arbustivas e arbóreas forrageiras. Para isso, uma amostragem foi realizada em março de 2010 em um experimento no campo, introduzindo pastagem degradada de Brachiaria decumbens, em julho de 2008, com sabiá (Mimosa caesalpiniifolia, leucena (Leucaena leucocephala, mororó (Bauhinia cheilantha e gliricídia (Gliricidia sepium, além de braquiária adubada e não adubada com N. As amostras de solo e serapilheira foram coletadas aos 0-10, 10-20 e 20-40 cm de profundidade, em três transectos, alternando pontos cobertos por gramíneas e leguminosas, totalizando sete amostras compostas por parcela para determinar pH, P, K, Ca, Mg e Al no solo, enquanto SB, t e m foram calculados. A serapilheira foi separada visualmente em leguminosas, gramíneas e materiais não identificados, em que foram utilizados para quantificação de matéria seca, matéria orgânica, N, P, C, fibra detergente ácido e lignina. A introdução das leguminosas aumentou os teores de N total na serapilheira e reduziu as relações C:N, com destaque para gliricídia e sabiá; entretanto, essa última apresentou elevados teores de lignina. Houve efeito significativo da cobertura por leguminosas, sem diferenças entre essas, para pH e K, na profundidade de 0-10 cm, e para Al e m, aos 10-20 cm de profundidade.

  20. Quantitative elemental determination of the particulate matter in the atmosphere of Pachuca city and the Real del Monte village, Hidalgo by means of PIXE technique; Determinacion elemental cuantitativa de la materia particulada en la atmosfera de la ciudad de Pachuca y el poblado de Real del Monte, Hidalgo, mediante la tecnica PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Guasso G, C.L. [ITT, 50000 Toluca (Mexico)

    2001-07-01

    All the pollutants that are generated so much of anthropogenic activities as natural cause effects to the health, and of course its increase the atmospheric pollution. Today in day for the great advance of the technology other pollutants are even generated but noxious to the human being's health, such it is the case of the particles, which are also called particulate matter airborne (MPA). This has motivated, to establish control measures leaning in collection strategies and certified analysis techniques, accurate and reliable. In the National Institute of Nuclear Research (ININ) they have been carried out studies on particulate matter airborne. In 1991 it was installed, calibrated and validated the nuclear technique of atomic origin based on proton beams known as PIXE. The characterization of the (MPA) it is carried out applying this technique and the collection by means of Dichotomous collectors (SFU). The thesis work that is presented next, includes the topic of the atmospheric pollution by particulate matter airborne (MPA) in a mining region, inside the Hidalgo State. The study was carried out during the 1998 winter season, only embracing the whole month of March in alternate days giving a total of 112 samples. Two sites that are highly active in the mining were studied, these are: the Real del Monte town and the Hidalgo state capital: Pachuca. Four samples per day were collected beginning to the 7:00 am--7:00 pm (daytime period) and concluding to the 7:00 pm -7:00 am (nocturne period). The characterization of its elementary content is carried out using the X-ray emission induced by particles technique (PIXE) that is a nuclear technique able to analyze 23 chemical elements beginning from the Al to the Pb, it requires of a very small sample quantity, it is very sensitive and it is not destructive. This characterization one carries out so much for fraction PM{sub 2.5} (fine) like as PM{sub 10} (thick) in both sites, also it was analyzed the temporary

  1. Extended Ensemble Monte Carlo

    OpenAIRE

    Iba, Yukito

    2000-01-01

    ``Extended Ensemble Monte Carlo''is a generic term that indicates a set of algorithms which are now popular in a variety of fields in physics and statistical information processing. Exchange Monte Carlo (Metropolis-Coupled Chain, Parallel Tempering), Simulated Tempering (Expanded Ensemble Monte Carlo), and Multicanonical Monte Carlo (Adaptive Umbrella Sampling) are typical members of this family. Here we give a cross-disciplinary survey of these algorithms with special emphasis on the great f...

  2. El colegio de teólogos y juristas «San Dionisio Aeropagita del Sacro-Monte de Granada» (1752-1800

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    Francisco MARTÍN ZUÑIGA

    2010-03-01

    Full Text Available RESUMEN: Los ocho siglos de vida islámica condicionan la plena integración de Granada en la sociedad española, y muy especialmente en el ámbito religioso: «carecía de una historia eclesiástica propiamente dicha, y aun los pocos datos existentes sobre la iglesia mozárabe de Ilíberis se desconocían entonces. Esta falta de datos ocasionó un vacío que pesaba mucho en los granadinos...Hasta las noticias del patrono —San Cecilio— caían prácticamente en la categoría de leyendas».

  3. Influence of shrub cover vegetal and slope length on soil bulk density; Influencia de la cubierta vegetal arbustiva y la longitud de la ladera sobre la densidad aparente del suelo

    Energy Technology Data Exchange (ETDEWEB)

    Bienes, R.; Jimenez, R.; Ruiz, M.; Garcia-Estringana, P.; Marques, M. J.

    2009-07-01

    In arid and semiarid environments of the Mediterranean climate, the shrub species play an important role in the revegetation of abandoned lands, which enables to control the soil losses, organic material and water. In this article are compared the results obtained under different revegetation in abandoned lands in the central area of Spain. In these revegetation has been used two native shrubs: A triplex halimus (Ah) and Retama sphaerocarpa (Rs), and were analyzed the influence of these revegetation in the contents of organic material of soil and apparent density in 5 years time after planting. As control, have been considered the pieces of ground with spontaneous vegetation abandoned in the same date that the shrubs revegetation. Atriplex halimus gives to the soil a covering capable to intercept a big amount of water drops absorbing a great amount part of the kinetic energy of the rain, while provides a microclimates as a result of be able to soften the wind, the temperature and the evaporation-transpiration, which makes it efficient to control the erosion and the desertification (Le Houerou, 2000). Retama sphaerocarpa was chosen because it is a native shrub very characteristic, and, due to its symbiosis with the Bradyrhizobium, enriches the soil in nitrogen, which is taken by the nitrophilous species enhancing the spontaneous vegetal covering. (Author) 9 refs.

  4. Monte Carlo simulation of the dose distribution around the {sup 125}I model 6711 seed as function of radius of the silver cylinder using the Penelope code; Simulacion por el Metodo de Monte Carlo de la distribucion de dosis alrededor de la semilla de {sup 125}I modelo 6711 en funcion del radio del cilindro de plata usando el codigo Penelope

    Energy Technology Data Exchange (ETDEWEB)

    Nerio, U. [Universidad de Cordoba, Monteria (Colombia); Instituto Nacional de Cancerologia, Bogota (Colombia); Chica, L. [Universidad Nacional de Colombia, Bogota (Colombia); Paul, A. [Universite de la Mediterranee, Marseille (France)

    2004-07-01

    The Monte Carlo method is applied to find the dose rates distribution in tissue around {sup 125} I seeds model 6711 as a function of the silver cylinder radius, R{sub sc} (0.017, 0.021, 0.025, 0.029 and 0.033) cm are used as radius values. It is found here that the dose rate at any point within the tissue decreases as R{sub sc} increases. The relative difference of dose rate that produced by the standard R{sub sc} seed, is less than 5%, for seeds with Rsc between 0.017 and 0.033 cm. (author)

  5. Estado actual de los estudios de conservación de las pinturas rupestres esquemáticas del Monte Valonsadero (Soria y propuestas para su protección y salvaguarda

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    Eugenio Sanz Pérez

    2000-01-01

    Full Text Available El primero de los autores reúne aquí su experiencia, de más de veinte años de estudio y seguimiento de las pinturas rupestres esquemáticas del Monte Valonsadero, con las síntesis —que él mismo traza y los demás autores anotan, corrigen o amplían— de los trabajos de estudio de la alteración de las areniscas que soportan los paneles pintados, de los análisis mineralógicos de sus pinturas y de la conservación y posible medidas para su protección, cuando se aproxima el año 2001, fecha en que este interesante núcleo de arte rupestre cumplirá cincuenta años de su descubrimiento. El interés de los autores está centrado en la necesidad de salvaguardar este tipo de manifestaciones, para lo cual entienden como prioritario el conocimiento de su estado de conservación y la llamada de atención a la Administración a fin de que ésta desarrolle sobre aquéllas cuantas actuaciones sean precisas para cumplir con la inexorable obligación de legarlas, al menos en su situación actual, a la posterioridad.The first one oí the authors assembles his experience of more than twenty-year-old study made of the schematic rock paintings in Monte Valonsadero, together with the syntheses —also made by him and later revised by the other authors— firstly of the studies of the alteration of the sandstone which support the paintings, secondly of the mineralogical analysis of the paint, and finally aiming to the preservation and possible actions for their protection. This article has an especial significance owing to the closeness of the year 2001, date on which the discovery of this interesting cave art nucleus will be fifty years of age. The main interest of tfie authors aims at the necessity of safeguarding tfiis type of paintings and ttiat is why they give priority to the knowledge of the preservation level in which the paintings are and, at the same time, they make a cali on the Authorities attention so that they could make any precise action

  6. El pavimento pretensado del Centro de Explotación de la Blécherette Mont-sur-Lausanne – Suiza

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    Editorial, Equipo

    1975-12-01

    establecimiento de un programa muy detallado de los trabajos a realizar, el cálculo, por su parte, hubo de tener en cuenta las especiales características de las sobrecargas que excluían, de entrada, la utilización de métodos empíricos. Los cálculos se hicieron con una cierta analogía respecto a los de un puente de carretera, pero con todos los elementos bidireccionales. Gracias al ordenador y después de alguna experiencia, el dimensionamiento del pretensado y la verificación de los esfuerzos de flexión se desarrollaron normalmente. Por ei contrario, al abordarse el control al punzonamiento de la losa y la seguridad a la rotura, se entró en un campo muy complejo en donde, a falta de investigaciones más profundas o de ensayos sobre modelo, los métodos tradicionales hubieron de ser adaptados con intuición y lógica.

  7. Monte Carlo methods

    OpenAIRE

    Bardenet, R.

    2012-01-01

    ISBN:978-2-7598-1032-1; International audience; Bayesian inference often requires integrating some function with respect to a posterior distribution. Monte Carlo methods are sampling algorithms that allow to compute these integrals numerically when they are not analytically tractable. We review here the basic principles and the most common Monte Carlo algorithms, among which rejection sampling, importance sampling and Monte Carlo Markov chain (MCMC) methods. We give intuition on the theoretic...

  8. Analysis of the uranium price predicted to 24 months, implementing neural networks and the Monte Carlo method like predictive tools; Analisis del precio del uranio pronosticado a 24 meses, implementando redes neuronales y el metodo de Monte Carlo como herramientas predictivas

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel E, J.; Ramirez S, J. R.; Palacios H, J. C., E-mail: jaime.esquivel@fi.uaemex.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2011-11-15

    The present work shows predicted prices of the uranium, using a neural network. The importance of predicting financial indexes of an energy resource, in this case, allows establishing budgetary measures, as well as the costs of the resource to medium period. The uranium is part of the main energy generating fuels and as such, its price rebounds in the financial analyses, due to this is appealed to predictive methods to obtain an outline referent to the financial behaviour that will have in a certain time. In this study, two methodologies are used for the prediction of the uranium price: the Monte Carlo method and the neural networks. These methods allow predicting the indexes of monthly costs, for a two years period, starting from the second bimonthly of 2011. For the prediction the uranium costs are used, registered from the year 2005. (Author)

  9. Exploring Monte Carlo methods

    CERN Document Server

    Dunn, William L

    2012-01-01

    Exploring Monte Carlo Methods is a basic text that describes the numerical methods that have come to be known as "Monte Carlo." The book treats the subject generically through the first eight chapters and, thus, should be of use to anyone who wants to learn to use Monte Carlo. The next two chapters focus on applications in nuclear engineering, which are illustrative of uses in other fields. Five appendices are included, which provide useful information on probability distributions, general-purpose Monte Carlo codes for radiation transport, and other matters. The famous "Buffon's needle proble

  10. Verification of the model of a photon beam of 6 MV in a Monte Carlo planning comparison with collapsed cone in in homogeneous medium; Verificacion del modelado de un haz de fotones de 6 MV en un planificador Monte Carlo. Comparacion con Collapsed Cone en medio no homogeneo

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Ros, J. C.; Jerez Sainz, M. I.; Lobato Munoz, M.; Jodar Lopez, C. A.; Ruiz Lopez, M. A.; Carrasco rodriguez, J. L.; Pamos Urena, M.

    2013-07-01

    We evaluated the Monte Carlo Monaco Planner v2.0.3 for calculation between non-homogeneous low density (equivalent to lung), as a complement to the verification of modeling in homogeneous medium and prior to the introduction of the SBRT technique. We performed the same tests on Pinnacle v8.0m, with the same purpose. We compare the results obtained with the algorithm Monte Carlo of Monaco and the Collapsed Cone of Pinnacle. (Author)

  11. MORSE Monte Carlo code

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, S.N.

    1984-01-01

    The MORSE code is a large general-use multigroup Monte Carlo code system. Although no claims can be made regarding its superiority in either theoretical details or Monte Carlo techniques, MORSE has been, since its inception at ORNL in the late 1960s, the most widely used Monte Carlo radiation transport code. The principal reason for this popularity is that MORSE is relatively easy to use, independent of any installation or distribution center, and it can be easily customized to fit almost any specific need. Features of the MORSE code are described.

  12. Quantum Monte Carlo simulation

    OpenAIRE

    Wang, Yazhen

    2011-01-01

    Contemporary scientific studies often rely on the understanding of complex quantum systems via computer simulation. This paper initiates the statistical study of quantum simulation and proposes a Monte Carlo method for estimating analytically intractable quantities. We derive the bias and variance for the proposed Monte Carlo quantum simulation estimator and establish the asymptotic theory for the estimator. The theory is used to design a computational scheme for minimizing the mean square er...

  13. Monte Carlo transition probabilities

    OpenAIRE

    Lucy, L. B.

    2001-01-01

    Transition probabilities governing the interaction of energy packets and matter are derived that allow Monte Carlo NLTE transfer codes to be constructed without simplifying the treatment of line formation. These probabilities are such that the Monte Carlo calculation asymptotically recovers the local emissivity of a gas in statistical equilibrium. Numerical experiments with one-point statistical equilibrium problems for Fe II and Hydrogen confirm this asymptotic behaviour. In addition, the re...

  14. Verification of the model of a photon beam of 6 MV in a Monte Carlo planning comparison with collapsed cone in homogeneous medium; Verificacion del modelado de un haz de fotones de 6 MV en un planificador Monte Carlo. Comparacion con collapsed cone en medio homegeneo

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Ros, J. C.; Jerez Sainz, M. I.; Jodar Lopez, C. A.; Lobato Munoz, M.; Ruiz Lopez, M. A.; Carrasco Rodriguez, J. L.; Pamos Urena, M.

    2013-07-01

    We evaluated the Monte Carlo Monaco Planner v2.0.3 by planners of the SEFM Protocol [1] to the modeling of the photon beam of 6 MV of a linear accelerator Elekta Synergy with collimator MLC Beam Modulator. We compare the Monte Carlo calculation with profiles on water measurement DFS = 100 cm, absorbed dose and dose levels for rectangular, asymmetric fields and different DFS. We compare the results with those obtained with the algorithm Collapsed Cone of Pinnacle Scheduler v8.0m. (Author)

  15. The Virtual Monte Carlo

    CERN Document Server

    Hrivnacova, I; Berejnov, V V; Brun, R; Carminati, F; Fassò, A; Futo, E; Gheata, A; Caballero, I G; Morsch, Andreas

    2003-01-01

    The concept of Virtual Monte Carlo (VMC) has been developed by the ALICE Software Project to allow different Monte Carlo simulation programs to run without changing the user code, such as the geometry definition, the detector response simulation or input and output formats. Recently, the VMC classes have been integrated into the ROOT framework, and the other relevant packages have been separated from the AliRoot framework and can be used individually by any other HEP project. The general concept of the VMC and its set of base classes provided in ROOT will be presented. Existing implementations for Geant3, Geant4 and FLUKA and simple examples of usage will be described.

  16. Monte Carlo and nonlinearities

    CERN Document Server

    Dauchet, Jérémi; Blanco, Stéphane; Caliot, Cyril; Charon, Julien; Coustet, Christophe; Hafi, Mouna El; Eymet, Vincent; Farges, Olivier; Forest, Vincent; Fournier, Richard; Galtier, Mathieu; Gautrais, Jacques; Khuong, Anaïs; Pelissier, Lionel; Piaud, Benjamin; Roger, Maxime; Terrée, Guillaume; Weitz, Sebastian

    2016-01-01

    The Monte Carlo method is widely used to numerically predict systems behaviour. However, its powerful incremental design assumes a strong premise which has severely limited application so far: the estimation process must combine linearly over dimensions. Here we show that this premise can be alleviated by projecting nonlinearities on a polynomial basis and increasing the configuration-space dimension. Considering phytoplankton growth in light-limited environments, radiative transfer in planetary atmospheres, electromagnetic scattering by particles and concentrated-solar-power-plant productions, we prove the real world usability of this advance on four test-cases that were so far regarded as impracticable by Monte Carlo approaches. We also illustrate an outstanding feature of our method when applied to sharp problems with interacting particles: handling rare events is now straightforward. Overall, our extension preserves the features that made the method popular: addressing nonlinearities does not compromise o...

  17. Fundamentals of Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Wollaber, Allan Benton [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-16

    This is a powerpoint presentation which serves as lecture material for the Parallel Computing summer school. It goes over the fundamentals of the Monte Carlo calculation method. The material is presented according to the following outline: Introduction (background, a simple example: estimating π), Why does this even work? (The Law of Large Numbers, The Central Limit Theorem), How to sample (inverse transform sampling, rejection), and An example from particle transport.

  18. Santiago del Estero: de rieles, obrajes y quebracho. Análisis de la configuración territorial del período técnico iniciado con la llegada del ferrocarril al monte chaco-santiagueño

    Directory of Open Access Journals (Sweden)

    María de Estrada

    2011-06-01

    Full Text Available En este trabajo se pretende analizar un período técnico específico para la configuración territorial de la provincia de Santiago del Estero signado por la llegada del ferrocarril. La introducción de este fenómeno técnico, comprendido como plantea Milton Santos (1996:36, no como una técnica específica, sino como totalidad que modificará por completo la organización del espacio, incorporará los obrajes como forma de organización de la mano de obra, transformará la localización de los centros poblados y generará la apertura a un mercado de tierras inmenso que será aprovechado por un grupo de capitalistas foráneos. La reconstrucción de este período específico es clave para comprender la relación entre el arrasamiento de los frondosos bosques del chaco santiagueño y el empobrecimiento de la población, así como la concentración de tierras en propietarios con orígenes e intereses lejanos al propio lugar.

  19. Conocimiento, uso y valor cultural de seis presas del jaguar (Panthera onca y su relación con éste, en San Nicolás de los Montes, San Luis Potosí, Mexico Knowledge, use and cultural value of six prey of jaguar (Panthera onca and their relationship with this species in San Nicolás de los Montes, San Luis Potosí, Mexico

    Directory of Open Access Journals (Sweden)

    Dulce M. Ávila-Nájera

    2011-09-01

    Full Text Available Durante 2007 se obtuvo información del conocimiento y la percepción que los pobladores del ejido tienen sobre el jaguar, sus presas y los factores que afectan la distribución y su conservación. Mediante el índice de importancia cultural (IIC se determinó el conocimiento que los ejidatarios tienen de las presas, y el uso y valor que les otorgan. Las presas que reconocieron importantes fueron venado cola blanca (Odocoileus virginianus, temazate (Mazama temama, pecarí (Tayassu pecari, tejón (Nasua narica, armadillo (Dasypus novemcinctus y tepezcuintle (Cuniculus paca; 72% de los encuestados también identificaron especies domésticas como presas del jaguar. Según su percepción, las más abundantes son pecarí, tejón y armadillo. El valor de uso más importante es el alimenticio, puesto que 82% de los encuestados ha consumido alguna especie silvestre. El valor más alto del IIC fue para el venado (27.17. En el ejido se considera perjudicial el jaguar por alimentarse del ganado. Los pobladores y los jaguares utilizan las mismas especies para obtener beneficio. El presente estudio constituye una base para el desarrollo de trabajos tendientes a manejar y conservar los recursos naturales que existen en el ejido considerando las necesidades de la población humana, de su fauna silvestre y la relación entre éstas.During 2007, we obtained information about the knowledge, perception of rural people regarding jaguar, its preys and the factors that affect its distribution and conservation. Additionally, we determined with the Index of Cultural Importance the knowledge, use and value that rural people assign to preys of the jaguar. They recognized as important prey species of the jaguar to white-tailed deer (Odocoileus virginianus, brocket (Mazama temama, pecari (Tayassu peccari, coati (Nasua narica, armadillo (Dasypus novemcinctus and paca (Cuniculus paca. Most of the villagers (72% identified also domestic species as preys of the jaguar

  20. Amenazas y oportunidades ante el cambio global en los montes españoles: el proyecto MONTES Consolider

    OpenAIRE

    Doblas Miranda, Enrique; Retana Alumbreros, Javier

    2011-01-01

    El mundo se enfrenta a una situación de cambio global en el que una combinación de alteraciones ambientales y bióticas (cambios en la composición atmosférica, en el clima, en el uso del suelo, en el régimen de incendios o en la introducción de especies) amenazan a muchos de los ecosistemas naturales y los servicios que estos proporcionan tales como mantenimiento del ciclo del carbono, la regulación de los recursos hídricos o la biodiversidad, entre otros. El proyecto MONTES surge como un prog...

  1. Circuitos del conocimiento: el Arte de la lengua índica de Valera y su inclusión en las polémicas sobre el Sacro Monte de Granada

    OpenAIRE

    José Alejandro Cárdenas Bunsen

    2014-01-01

    ResumenA partir del examen de documentos inéditos, este artículo muestra que Blas Valera (1545-1597) fue autor de un Arte de la lengua índica, que circulaba en Sevilla en 1595. Sostiene también que Valera puede ser identificado como el director detrás del Arte y vocabulario en la lengua general del Perú, publicado anónimamente en 1586. El estudio reconstruye, además, el contexto intelectual que hizo posible la circulación de la obra de Valera y los criterios filológicos que permitieron insert...

  2. Monts Jura Jazz Festival

    CERN Multimedia

    2012-01-01

    The 5th edition of the "Monts Jura Jazz Festival" will take place at the Esplanade du Lac in Divonne-les-Bains, France on September 21 and 22. This festival organized by the CERN Jazz Club and supported by the CERN Staff Association is becoming a major musical event in the Geneva region. International Jazz artists like Didier Lockwood and David Reinhardt are part of this year outstanding program. Full program and e-tickets are available on the festival website. Don't miss this great festival!

  3. Monts Jura Jazz Festival

    CERN Multimedia

    Jazz Club

    2012-01-01

    The 5th edition of the "Monts Jura Jazz Festival" that will take place on September 21st and 22nd 2012 at the Esplanade du Lac in Divonne-les-Bains. This festival is organized by the "CERN Jazz Club" with the support of the "CERN Staff Association". This festival is a major musical event in the French/Swiss area and proposes a world class program with jazz artists such as D.Lockwood and D.Reinhardt. More information on http://www.jurajazz.com.

  4. MCMini: Monte Carlo on GPGPU

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, Ryan C. [Los Alamos National Laboratory

    2012-07-25

    MCMini is a proof of concept that demonstrates the possibility for Monte Carlo neutron transport using OpenCL with a focus on performance. This implementation, written in C, shows that tracing particles and calculating reactions on a 3D mesh can be done in a highly scalable fashion. These results demonstrate a potential path forward for MCNP or other Monte Carlo codes.

  5. Monte Carlo methods for electromagnetics

    CERN Document Server

    Sadiku, Matthew NO

    2009-01-01

    Until now, novices had to painstakingly dig through the literature to discover how to use Monte Carlo techniques for solving electromagnetic problems. Written by one of the foremost researchers in the field, Monte Carlo Methods for Electromagnetics provides a solid understanding of these methods and their applications in electromagnetic computation. Including much of his own work, the author brings together essential information from several different publications.Using a simple, clear writing style, the author begins with a historical background and review of electromagnetic theory. After addressing probability and statistics, he introduces the finite difference method as well as the fixed and floating random walk Monte Carlo methods. The text then applies the Exodus method to Laplace's and Poisson's equations and presents Monte Carlo techniques for handing Neumann problems. It also deals with whole field computation using the Markov chain, applies Monte Carlo methods to time-varying diffusion problems, and ...

  6. Metropolis Methods for Quantum Monte Carlo Simulations

    OpenAIRE

    Ceperley, D. M.

    2003-01-01

    Since its first description fifty years ago, the Metropolis Monte Carlo method has been used in a variety of different ways for the simulation of continuum quantum many-body systems. This paper will consider some of the generalizations of the Metropolis algorithm employed in quantum Monte Carlo: Variational Monte Carlo, dynamical methods for projector monte carlo ({\\it i.e.} diffusion Monte Carlo with rejection), multilevel sampling in path integral Monte Carlo, the sampling of permutations, ...

  7. Gestión de Emisiones de Gases de Efecto Invernadero como parte de la Estrategia de Sostenibilidad de la Escuela Técnica Superior de Ingeniería de Montes, Forestal y del Medio Natural

    OpenAIRE

    Rodríguez Cuesta, Carla

    2015-01-01

    Las consecuencias ambientales, sociales y económicas que conlleva el cambio climático, enfatizan la creciente preocupación por desarrollar estrategias, medidas y acciones de prevención, adaptación y mitigación del mismo. La aplicación de buenas prácticas integradas en el modelo de gestión de las organizaciones bajo los criterios de responsabilidad social y sostenibilidad permite: tener un mayor control de riesgos, identificar nuevas oportunidades, mejorar relaciones con los grupos de interés,...

  8. Simulations of electrical asymmetry effect on N2-H2 capacitively coupled plasma by particle-in-cell/Monte Carlo mo del%N2-H2容性耦合等离子体电非对称效应的particle-in-cell/Monte Carlo模拟

    Institute of Scientific and Technical Information of China (English)

    郝莹莹; 孟秀兰; 姚福宝; 赵国明; 王敬; 张连珠

    2014-01-01

    H2-N2混合气体电容性耦合射频放电在有机低介电系数材料刻蚀中具潜在研究意义.采用particle-in-cell/Monte Carlo模型模拟了双频(13.56 MHz/27.12 MHz)电压源分别接在结构对称的两个电极上的H2-N2容性耦合等离子体特征,研究了其电非对称效应.模拟结果表明,通过调节两谐波间的相位角θ,可以改变其电场、等离子体密度、离子流密度的轴向分布及离子轰击电极的能量分布.当相位角θ为0◦时,低频电极(晶片)附近主要离子(H+3)的密度最小,离子(H+3, H+2, H+)轰击低频电极的流密度及平均能量最高;当θ从0◦变化90◦时,低频电极的自偏压从-103 V到106 V近似线性增加,轰击电极的离子流密度变化约±18%, H+离子轰击低频电极的最大能量约减小2.5倍,轰击电极的平均能量约变化2倍,表明氢离子能量和离子流几乎能独立控制.%A N2-H2 capacitively coupled rf discharge has potential applications in etching of organic low dielectric constant (low-k) material for microelectronics technology. In this paper, we investigate the characteristic and electrical asymmetry effect (EAE) on the N2-H2 capacitively coupled plasma used for low-k material etching by particle-in-cell/Monte Carlo (PIC/MC) model, in which the two frequency sources of 13.56 MHz and 27.12 MHz are applied separately to the two electrodes in geometrically in symmetry. It is found that the plasma density profiles, the ion flux density profiles and the energy distribution of ion bombarding electrodes can be changed by adjusting the phase angle θ between the two harmonics. When the phase angle θ is 0◦, the density of primary ion (H+3 ) near low frequencie electrode (LFE) (wafer) is smallest, whereas flux and average energy of ion (H+, H+3 , H+2 ) bombarding LFE are biggest; if the phase angle θ is tuned from 0◦ to 90◦, the dc self-bias increases almost linearly from -103 V to 106 V, ion flux bombarding the LFE decreases by

  9. Desarrollo Integral del Escolar

    OpenAIRE

    Cañas Giraldo, Camilo Augusto

    2014-01-01

    La pediatría comprende cinco grupos de edades cuyos patrones de crecimiento, requerimientos nutricionales, comportamientos biológicos, y sobretodo comportamiento psicoafectivo, son diferentes. En la Carta de la Salud de febrero de 2013, la Dra. Patricia Montes había explicado el desarrollo del niño pre-escolar. En esta ocasión la Carta de la Salud versará sobre el desarrollo del niño escolar. Esta etapa se caracteriza por la creatividad y la ingeniosidad, pues p...

  10. Monte Carlo integration on GPU

    OpenAIRE

    Kanzaki, J.

    2010-01-01

    We use a graphics processing unit (GPU) for fast computations of Monte Carlo integrations. Two widely used Monte Carlo integration programs, VEGAS and BASES, are parallelized on GPU. By using $W^{+}$ plus multi-gluon production processes at LHC, we test integrated cross sections and execution time for programs in FORTRAN and C on CPU and those on GPU. Integrated results agree with each other within statistical errors. Execution time of programs on GPU run about 50 times faster than those in C...

  11. Amenazas y oportunidades ante el cambio global en los montes españoles: el proyecto MONTES Consolider

    Directory of Open Access Journals (Sweden)

    E. Doblas-Miranda

    2011-01-01

    Full Text Available El mundo se enfrenta a una situación de cambio global en el que una combinación de alteraciones ambientales y bióticas (cambios en la composición atmosférica, en el clima, en el uso del suelo, en el régimen de incendios o en la introducción de especies amenazan a muchos de los ecosistemas naturales y los servicios que estos proporcionan tales como mantenimiento del ciclo del carbono, la regulación de los recursos hídricos o la biodiversidad, entre otros. El proyecto MONTES surge como un programa de investigación sobre la relación entre los factores de cambio global y los servicios ecosistémicos en el monte mediterráneo, con el objetivo de orientar las oportunidades de manejo forestal y su adaptación al cambio. Este objetivo se organiza en tres ejes que combinan el análisis de la influencia del cambio global en el monte, el modo en que el monte puede a su vez modificar los efectos del cambio global y la variación de dichas interacciones mediante la gestión forestal. Para ello, MONTES se encuentra estructurado en siete módulos de trabajo que condensan todas las posibles interacciones entre factores y servicios: (1 las interacciones entre el monte y la atmósfera, (2 cambios en la fijación de carbono en los montes, (3 cambios en la distribución de especies causados por el cambio climático, (4 consecuencias sobre la disponibilidad de agua, (5 consecuencias de los cambios de uso del suelo y fragmentación en la conservación de especies, (6 vulnerabilidad de las especies al fuego y gestión preventiva de los grandes incendios, (7 invasiones ecológicas y consecuencias en la biodiversidad, más un octavo módulo centrado en la transversalidad e interacciones entre módulos. El proyecto incorpora la escala de parcela, local y regional utilizando información existente y a través de nueve áreas de estudio distribuidas por toda España que cubren montañas no mediterráneas (Pirineos y Montseny, montañas (Sierra Nevada, Alto Tajo

  12. Relationships between Prosopis flexuosa (Fabaceae and cattle in the Monte desert: Seeds, seedlings and saplings on cattle-use site classes Interacciones entre Prosopis flexuosa (Fabaceae y el ganado en el desierto de Monte: Semillas, plántulas y renovales en los sitios de uso del ganado

    Directory of Open Access Journals (Sweden)

    CLAUDIA M CAMPOS

    2011-06-01

    , or sapling, defecation and trampling appear to be important processes in the seed dispersal cycle. In this sense, cattle could benefit the establishment of P. flexuosa.El destino de las semillas de Prosopis flexuosa dispersadas por ganado depende de los patrones de deposición de excrementos y movimientos de forrajeo. Nuestra hipótesis es que las variables respuesta relacionadas con el aporte y el destino de semillas, plántulas y renovales son explicadas por diferencias entre los sitios de actividad del ganado. Definimos sitios con alto tránsito de animales ("senderos" y "periferia de senderos", sitios utilizados para descanso y alimentación ("bajo Prosopis" y sitios de paso para animales aislados ("bajo arbustos" y "suelo descubierto". Considerando los sitios de actividad establecidos, nuestros objetivos fueron cuantificar y comparar: (1 semillas transportadas en los excrementos, (2 plántulas 10 meses después de la deposición, (3 renovales establecidos, (4 semillas germinadas en los excrementos, supervivencia de plántulas y semillas que permanecieron en los excrementos. El trabajo se realizó en un campo ganadero de Ñacuñán (Mendoza, Argentina, dentro de cuatro áreas donde se establecieron parcelas de 25 ha. En los sitios se encontró un aporte diferencial de semillas: en sitios de descanso y alimentación ("bajo Prosopis" y de tránsito intenso ("periferia" los animales depositaron las mayores cantidades de semillas. Diez meses después, las semillas germinaron con las primeras lluvias; el mayor número de plántulas se registró en sitios de tránsito intenso ("senderos" y "periferia" y de descanso y alimentación ("bajo Prosopis". A largo plazo, en la "periferia" se establece la mayor cantidad de renovales. Inmediatamente después de la deposición, germinó un número muy bajo de semillas y las plántulas no sobrevivieron más de una semana. En los sitios más transitados por el ganado, los excrementos se desintegraron por pisoteo y la persistencia

  13. Florística e fitogeografia da vegetação arbustiva subcaducifólia da Chapada de São José, Buíque, PE, Brasil Floristics and phytogeography of semideciduous vegetation on the São José plateau, Buíque, Pernambuco State, Brazil

    Directory of Open Access Journals (Sweden)

    Ana Paula de Souza Gomes

    2006-03-01

    Full Text Available Foi realizado o levantamento da flora angiospérmica de um trecho de vegetação arbustiva subcaducifólia na Chapada de São José, Buíque, Pernambuco, com a finalidade de ampliar o conhecimento sobre a flora daquela chapada, bem como compreender suas relações florísticas com outros conjuntos vegetacionais do Nordeste, especialmente no semi-árido. A flora angiospérmica foi composta por 192 táxons, distribuídos em 130 gêneros e 60 famílias. Euphorbiaceae, Caesalpiniaceae, Myrtaceae, Mimosaceae, Fabaceae e Cactaceae foram as mais representativas em número de espécies. A análise de agrupamento revelou que o tipo de substrato exerce uma forte influência na repartição espacial das espécies dentro do semi-árido e confirmou a existência de um conjunto de espécies indicadoras das áreas sedimentares, formado por Caesalpinia microphylla Mart. (Caesalpiniaceae, Bocoa mollis (Benth. R.S. Cowan (Fabaceae, Byrsonima gardneriana A. Juss. (Malpighiaceae e Zanthoxylum stelligerum Turic. (Rutaceae. A flora da área de estudo é relacionada com a da caatinga do cristalino, caatinga de áreas sedimentares e carrasco. Todavia, o alto número de espécies de Myrtaceae, raras na caatinga, o carácter subcaducifólio da vegetação e a presença de Cactaceae e Bromeliaceae, típicas da caatinga, sugerem que a área de estudo representa o final de um gradiente que se inicia em áreas sedimentares situadas em menores altitudes.A floristic survey was carried out in a semideciduous vegetation on São José plateau with the objective of amplifying the knowledge of its angiospermic flora and establishing its relationship with other vegetations types in the semi-arid region of Northeast Brazil. The flora was composed by 192 taxa belonging to 130 genera and 60 families. Euphorbiaceae, Caesalpiniaceae, Myrtaceae, Mimosaceae Fabaceae and Cactaceae were the families with the highest numbers of species. A cluster analysis indicated influence of the soil type

  14. Estoque de serapilheira e fertilidade do solo em pastagem degradada de Brachiaria decumbens após implantação de leguminosas arbustivas e arbóreas forrageiras Soil litter stock and fertility after planting leguminous shrubs and forage trees on degraded signal grass pasture

    Directory of Open Access Journals (Sweden)

    André Barbosa Silva

    2013-04-01

    Full Text Available As pastagens formam a base da pecuária brasileira; essas sofrem degradação em larga escala por deficiência de nitrogênio (N. O consórcio com leguminosas, além de fixar N, pode apresentar outros efeitos na fertilidade do solo como acidificação ou retirada de nutrientes de camadas mais profundas para as mais superficiais. Este trabalho objetivou avaliar o estoque de serapilheira e a fertilidade do solo em pastagens degradadas de braquiária (Brachiaria decumbens, após implantar leguminosas arbustivas e arbóreas forrageiras. Para isso, uma amostragem foi realizada em março de 2010 em um experimento no campo, introduzindo pastagem degradada de Brachiaria decumbens, em julho de 2008, com sabiá (Mimosa caesalpiniifolia, leucena (Leucaena leucocephala, mororó (Bauhinia cheilantha e gliricídia (Gliricidia sepium, além de braquiária adubada e não adubada com N. As amostras de solo e serapilheira foram coletadas aos 0-10, 10-20 e 20-40 cm de profundidade, em três transectos, alternando pontos cobertos por gramíneas e leguminosas, totalizando sete amostras compostas por parcela para determinar pH, P, K, Ca, Mg e Al no solo, enquanto SB, t e m foram calculados. A serapilheira foi separada visualmente em leguminosas, gramíneas e materiais não identificados, em que foram utilizados para quantificação de matéria seca, matéria orgânica, N, P, C, fibra detergente ácido e lignina. A introdução das leguminosas aumentou os teores de N total na serapilheira e reduziu as relações C:N, com destaque para gliricídia e sabiá; entretanto, essa última apresentou elevados teores de lignina. Houve efeito significativo da cobertura por leguminosas, sem diferenças entre essas, para pH e K, na profundidade de 0-10 cm, e para Al e m, aos 10-20 cm de profundidade.Pastures are the fodder supply of Brazilian livestock, and are exhaustively degraded by nitrogen (N deficiency. Intercropping with legumes, aside from nitrogen fixation, may have

  15. Are the vegetation structure and composition of the shrubby Caatinga free from edge influence? A estrutura e a composição da vegetação da Caatinga arbustiva são livres da influência de borda?

    Directory of Open Access Journals (Sweden)

    André Maurício de Melo Santos

    2008-12-01

    Full Text Available Edge influence, or edge effect, drives many biological changes in fragmented landscapes. This has been extensively studied in many forest ecosystems, but it remains to be described for the Brazilian Caatinga. Based on the biotic and physical conditions of the shrubby Caatinga, our prediction a priori was that this type of vegetation is free from edge influence in terms of vegetation structure and composition. We sampled shrubs, cacti and trees in twenty 200 m² plots on old edges (>60 yrs old and interior of a 690 ha fragment, partially isolated and surrounded by Opuntia ficus-indica cacti. Plant height, stem diameter at ground level, stem density, species richness and diversity were statistically equal between edge and interior habitats. Magnitude of edge influence varied from -0.027 to 0.027, indicating low ecological importance of edge creation for the measured variables. Additionally, floristic similarity between habitats was 90% and a principal component analysis showed that species composition varied in a similar manner at edges and interiors. These results indicate that the vegetation of the sampled fragment is not ecologically affected by the creation of edges and suggests that changes in physical conditions and resource availability after edge creation are not enough to eliminate established plants or to alter recruitment and survival of new individuals.A influência de borda, ou efeito de borda, leva a diversas alterações biológicas em paisagens fragmentadas. Embora muito estudada em ecossistemas florestais, a influência de borda permanece desconhecida para a Caatinga. Baseada nas condições físicas e biológicas da Caatinga arbustiva, nossa predição a priori foi que este tipo de vegetação não sofre influência de borda em termos de estrutura e composição de espécies. Nós amostramos arbustos, cactos e árvores em 20 parcelas de 200 m² em bordas antigas (> 60 anos de idade e interiores de um fragmento de 690 ha

  16. Multilevel sequential Monte Carlo samplers

    KAUST Repository

    Beskos, Alexandros

    2016-08-29

    In this article we consider the approximation of expectations w.r.t. probability distributions associated to the solution of partial differential equations (PDEs); this scenario appears routinely in Bayesian inverse problems. In practice, one often has to solve the associated PDE numerically, using, for instance finite element methods which depend on the step-size level . hL. In addition, the expectation cannot be computed analytically and one often resorts to Monte Carlo methods. In the context of this problem, it is known that the introduction of the multilevel Monte Carlo (MLMC) method can reduce the amount of computational effort to estimate expectations, for a given level of error. This is achieved via a telescoping identity associated to a Monte Carlo approximation of a sequence of probability distributions with discretization levels . ∞>h0>h1⋯>hL. In many practical problems of interest, one cannot achieve an i.i.d. sampling of the associated sequence and a sequential Monte Carlo (SMC) version of the MLMC method is introduced to deal with this problem. It is shown that under appropriate assumptions, the attractive property of a reduction of the amount of computational effort to estimate expectations, for a given level of error, can be maintained within the SMC context. That is, relative to exact sampling and Monte Carlo for the distribution at the finest level . hL. The approach is numerically illustrated on a Bayesian inverse problem. © 2016 Elsevier B.V.

  17. Classes sucessionais e síndromes de dispersão de espécie arbóreas e arbustivas existentes em vegetação ciliar remanescente (Conchal, SP, como subsídio para avaliar o potencial do fragmento como fonte de propágulos para enriquecimento de áreas revegetadas no Rio Mogi-Guaçu, SP Successional groups and dispersal syndromes of tree and shrub species at the riparian forest fragment in Conchal, SP, Brazil to evaluate its potential as a source of seeds to the enrichment of revegetated riparian areas along the Mogi-Guaçu River, SP

    Directory of Open Access Journals (Sweden)

    Clarissa de Aquino

    2009-04-01

    Full Text Available Este estudo foi realizado em fragmento de vegetação ciliar remanescente, localizado à margem direita do rio Mogi-Guaçu, Município de Conchal, SP, tendo como objetivo a avaliação do potencial desse fragmento como fonte de propágulos para projetos de enriquecimento em áreas ciliares implantadas na região de Mogi-Guaçu, SP. Para tanto, foi realizada a caracterização sucessional e da síndrome de dispersão das espécies arbóreas e arbustivas. No local, foram registradas 99 espécies arbóreas e arbustivas, pertencentes a 38 famílias. As famílias com maior número de espécies foram Euphorbiaceae, Fabaceae, Myrtaceae e Rubiaceae. Quanto aos grupos sucessionais, foi verificado equilíbrio na quantidade de espécies secundárias tardias (28,3% e daquelas típicas de sub-bosque (23,2%. A síndrome de dispersão predominante entre as espécies arbóreas e arbustivas foi a zoocoria, identificada em 64,6% delas, seguida pela anemocoria, que representou 20,2% dos casos. Os resultados gerais apontaram o bom estado de conservação desse fragmento e a viabilidade de sua utilização como fonte de propágulos para ações de revegetação em áreas ciliares da região.This work was conducted in a reminiscent Riparian forest fragment at the Mogi-Guaçu River, in Conchal, SP, Brazil, to evaluate the potential of this fragment as a seed supplier to other projects regarding the preservation and enrichment of this type of forest in the region. Thus, the tree and scrub species sampled in floristic surveys were classified according to their dispersal syndromes and successional groups, with 38 families and 99 species being recorded in the area. The families with the most species were Euphorbiaceae, Fabaceae, Myrtaceae, and Rubiaceae. A balance was observed between late secondary species (28.3% and understory species (23.2%. Zoochory was the most frequently observed syndrome (64.6%, followed by anemochory (20.2%. These results show the good

  18. Equilibrium Statistics: Monte Carlo Methods

    Science.gov (United States)

    Kröger, Martin

    Monte Carlo methods use random numbers, or ‘random’ sequences, to sample from a known shape of a distribution, or to extract distribution by other means. and, in the context of this book, to (i) generate representative equilibrated samples prior being subjected to external fields, or (ii) evaluate high-dimensional integrals. Recipes for both topics, and some more general methods, are summarized in this chapter. It is important to realize, that Monte Carlo should be as artificial as possible to be efficient and elegant. Advanced Monte Carlo ‘moves’, required to optimize the speed of algorithms for a particular problem at hand, are outside the scope of this brief introduction. One particular modern example is the wavelet-accelerated MC sampling of polymer chains [406].

  19. Monte Carlo Hamiltonian: Linear Potentials

    Institute of Scientific and Technical Information of China (English)

    LUO Xiang-Qian; LIU Jin-Jiang; HUANG Chun-Qing; JIANG Jun-Qin; Helmut KROGER

    2002-01-01

    We further study the validity of the Monte Carlo Hamiltonian method. The advantage of the method,in comparison with the standard Monte Carlo Lagrangian approach, is its capability to study the excited states. Weconsider two quantum mechanical models: a symmetric one V(x) = |x|/2; and an asymmetric one V(x) = ∞, forx < 0 and V(x) = x, for x ≥ 0. The results for the spectrum, wave functions and thermodynamical observables are inagreement with the analytical or Runge-Kutta calculations.

  20. Proton Upset Monte Carlo Simulation

    Science.gov (United States)

    O'Neill, Patrick M.; Kouba, Coy K.; Foster, Charles C.

    2009-01-01

    The Proton Upset Monte Carlo Simulation (PROPSET) program calculates the frequency of on-orbit upsets in computer chips (for given orbits such as Low Earth Orbit, Lunar Orbit, and the like) from proton bombardment based on the results of heavy ion testing alone. The software simulates the bombardment of modern microelectronic components (computer chips) with high-energy (.200 MeV) protons. The nuclear interaction of the proton with the silicon of the chip is modeled and nuclear fragments from this interaction are tracked using Monte Carlo techniques to produce statistically accurate predictions.

  1. Monte Carlo Particle Lists: MCPL

    CERN Document Server

    Kittelmann, Thomas; Knudsen, Erik B; Willendrup, Peter; Cai, Xiao Xiao; Kanaki, Kalliopi

    2016-01-01

    A binary format with lists of particle state information, for interchanging particles between various Monte Carlo simulation applications, is presented. Portable C code for file manipulation is made available to the scientific community, along with converters and plugins for several popular simulation packages.

  2. Applications of Monte Carlo Methods in Calculus.

    Science.gov (United States)

    Gordon, Sheldon P.; Gordon, Florence S.

    1990-01-01

    Discusses the application of probabilistic ideas, especially Monte Carlo simulation, to calculus. Describes some applications using the Monte Carlo method: Riemann sums; maximizing and minimizing a function; mean value theorems; and testing conjectures. (YP)

  3. Simulaciones Monte Carlo de remanentes de supernova en galaxias espirales

    OpenAIRE

    García Carrasco, Víctor

    2008-01-01

    Actualmente sabemos que las explosiones de supernova son el principal aporte de energía y metales al medio interestelar (ISM) por lo que el estudio de sus remanentes nos debería permitir conocer mejor las características del ISM en el que se hallan, las cuales inuyen fuertemente en su evolución. Para contrastar los datos observacionales, aportados principalmente por Chandra y XMM-Newton, con la teoría vamos a construir un código Monte Carlo que simule un modelo de galaxia en el que se reprodu...

  4. Density matrix quantum Monte Carlo

    CERN Document Server

    Blunt, N S; Spencer, J S; Foulkes, W M C

    2013-01-01

    This paper describes a quantum Monte Carlo method capable of sampling the full density matrix of a many-particle system, thus granting access to arbitrary reduced density matrices and allowing expectation values of complicated non-local operators to be evaluated easily. The direct sampling of the density matrix also raises the possibility of calculating previously inaccessible entanglement measures. The algorithm closely resembles the recently introduced full configuration interaction quantum Monte Carlo method, but works all the way from infinite to zero temperature. We explain the theory underlying the method, describe the algorithm, and introduce an importance-sampling procedure to improve the stochastic efficiency. To demonstrate the potential of our approach, the energy and staggered magnetization of the isotropic antiferromagnetic Heisenberg model on small lattices and the concurrence of one-dimensional spin rings are compared to exact or well-established results. Finally, the nature of the sign problem...

  5. Efficient kinetic Monte Carlo simulation

    Science.gov (United States)

    Schulze, Tim P.

    2008-02-01

    This paper concerns kinetic Monte Carlo (KMC) algorithms that have a single-event execution time independent of the system size. Two methods are presented—one that combines the use of inverted-list data structures with rejection Monte Carlo and a second that combines inverted lists with the Marsaglia-Norman-Cannon algorithm. The resulting algorithms apply to models with rates that are determined by the local environment but are otherwise arbitrary, time-dependent and spatially heterogeneous. While especially useful for crystal growth simulation, the algorithms are presented from the point of view that KMC is the numerical task of simulating a single realization of a Markov process, allowing application to a broad range of areas where heterogeneous random walks are the dominate simulation cost.

  6. Adaptive Multilevel Monte Carlo Simulation

    KAUST Repository

    Hoel, H

    2011-08-23

    This work generalizes a multilevel forward Euler Monte Carlo method introduced in Michael B. Giles. (Michael Giles. Oper. Res. 56(3):607–617, 2008.) for the approximation of expected values depending on the solution to an Itô stochastic differential equation. The work (Michael Giles. Oper. Res. 56(3):607– 617, 2008.) proposed and analyzed a forward Euler multilevelMonte Carlo method based on a hierarchy of uniform time discretizations and control variates to reduce the computational effort required by a standard, single level, Forward Euler Monte Carlo method. This work introduces an adaptive hierarchy of non uniform time discretizations, generated by an adaptive algorithmintroduced in (AnnaDzougoutov et al. Raùl Tempone. Adaptive Monte Carlo algorithms for stopped diffusion. In Multiscale methods in science and engineering, volume 44 of Lect. Notes Comput. Sci. Eng., pages 59–88. Springer, Berlin, 2005; Kyoung-Sook Moon et al. Stoch. Anal. Appl. 23(3):511–558, 2005; Kyoung-Sook Moon et al. An adaptive algorithm for ordinary, stochastic and partial differential equations. In Recent advances in adaptive computation, volume 383 of Contemp. Math., pages 325–343. Amer. Math. Soc., Providence, RI, 2005.). This form of the adaptive algorithm generates stochastic, path dependent, time steps and is based on a posteriori error expansions first developed in (Anders Szepessy et al. Comm. Pure Appl. Math. 54(10):1169– 1214, 2001). Our numerical results for a stopped diffusion problem, exhibit savings in the computational cost to achieve an accuracy of ϑ(TOL),from(TOL−3), from using a single level version of the adaptive algorithm to ϑ(((TOL−1)log(TOL))2).

  7. Monte Carlo approach to turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Dueben, P.; Homeier, D.; Muenster, G. [Muenster Univ. (Germany). Inst. fuer Theoretische Physik; Jansen, K. [DESY, Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Mesterhazy, D. [Humboldt Univ., Berlin (Germany). Inst. fuer Physik

    2009-11-15

    The behavior of the one-dimensional random-force-driven Burgers equation is investigated in the path integral formalism on a discrete space-time lattice. We show that by means of Monte Carlo methods one may evaluate observables, such as structure functions, as ensemble averages over different field realizations. The regularization of shock solutions to the zero-viscosity limit (Hopf-equation) eventually leads to constraints on lattice parameters required for the stability of the simulations. Insight into the formation of localized structures (shocks) and their dynamics is obtained. (orig.)

  8. Monte Carlo techniques in radiation therapy

    CERN Document Server

    Verhaegen, Frank

    2013-01-01

    Modern cancer treatment relies on Monte Carlo simulations to help radiotherapists and clinical physicists better understand and compute radiation dose from imaging devices as well as exploit four-dimensional imaging data. With Monte Carlo-based treatment planning tools now available from commercial vendors, a complete transition to Monte Carlo-based dose calculation methods in radiotherapy could likely take place in the next decade. Monte Carlo Techniques in Radiation Therapy explores the use of Monte Carlo methods for modeling various features of internal and external radiation sources, including light ion beams. The book-the first of its kind-addresses applications of the Monte Carlo particle transport simulation technique in radiation therapy, mainly focusing on external beam radiotherapy and brachytherapy. It presents the mathematical and technical aspects of the methods in particle transport simulations. The book also discusses the modeling of medical linacs and other irradiation devices; issues specific...

  9. Mean field simulation for Monte Carlo integration

    CERN Document Server

    Del Moral, Pierre

    2013-01-01

    In the last three decades, there has been a dramatic increase in the use of interacting particle methods as a powerful tool in real-world applications of Monte Carlo simulation in computational physics, population biology, computer sciences, and statistical machine learning. Ideally suited to parallel and distributed computation, these advanced particle algorithms include nonlinear interacting jump diffusions; quantum, diffusion, and resampled Monte Carlo methods; Feynman-Kac particle models; genetic and evolutionary algorithms; sequential Monte Carlo methods; adaptive and interacting Marko

  10. Approaching Chemical Accuracy with Quantum Monte Carlo

    OpenAIRE

    Petruzielo, Frank R.; Toulouse, Julien; Umrigar, C. J.

    2012-01-01

    International audience; A quantum Monte Carlo study of the atomization energies for the G2 set of molecules is presented. Basis size dependence of diffusion Monte Carlo atomization energies is studied with a single determinant Slater-Jastrow trial wavefunction formed from Hartree-Fock orbitals. With the largest basis set, the mean absolute deviation from experimental atomization energies for the G2 set is 3.0 kcal/mol. Optimizing the orbitals within variational Monte Carlo improves the agreem...

  11. MONTE ALBÁN Y EL COLAPSO CLÁSICO SEGÚN EL REGISTRO FUNERARIO (Monte Alban and the Classic Collapse from the Mortuary Record

    Directory of Open Access Journals (Sweden)

    Pascual Izquierdo-Egea

    2016-12-01

    Full Text Available La aplicación del método de valoración contextual al análisis del registro funerario de Monte Albán (Oaxaca, México aporta nuevas evidencias sobre la huella material del colapso clásico en las ofrendas de los entierros mesoamericanos. Esto confirma lo que ya se había anticipado al estudiar la cuenca del río Balsas en México y, entre los mayas, la región de Petén en Guatemala y el valle del río Belice (2014-2015. ENGLISH: Application of the contextual valuation method to the mortuary analysis of Monte Alban (Oaxaca, Mexico provides new evidence on the Classic collapse. Grave goods from Mesoamerican burials confirm results of my studies from both the Balsas River basin in Mexico and, among the Maya, the Peten region in Guatemala and the Belize River valley (2014–5.

  12. 1-D EQUILIBRIUM DISCRETE DIFFUSION MONTE CARLO

    Energy Technology Data Exchange (ETDEWEB)

    T. EVANS; ET AL

    2000-08-01

    We present a new hybrid Monte Carlo method for 1-D equilibrium diffusion problems in which the radiation field coexists with matter in local thermodynamic equilibrium. This method, the Equilibrium Discrete Diffusion Monte Carlo (EqDDMC) method, combines Monte Carlo particles with spatially discrete diffusion solutions. We verify the EqDDMC method with computational results from three slab problems. The EqDDMC method represents an incremental step toward applying this hybrid methodology to non-equilibrium diffusion, where it could be simultaneously coupled to Monte Carlo transport.

  13. Monte Carlo Treatment Planning for Advanced Radiotherapy

    DEFF Research Database (Denmark)

    Cronholm, Rickard

    and validation of a Monte Carlo model of a medical linear accelerator (i), converting a CT scan of a patient to a Monte Carlo compliant phantom (ii) and translating the treatment plan parameters (including beam energy, angles of incidence, collimator settings etc) to a Monte Carlo input file (iii). A protocol...... previous algorithms since it uses delineations of structures in order to include and/or exclude certain media in various anatomical regions. This method has the potential to reduce anatomically irrelevant media assignment. In house MATLAB scripts translating the treatment plan parameters to Monte Carlo...

  14. Error in Monte Carlo, quasi-error in Quasi-Monte Carlo

    OpenAIRE

    Kleiss, R. H. P.; Lazopoulos, A.

    2006-01-01

    While the Quasi-Monte Carlo method of numerical integration achieves smaller integration error than standard Monte Carlo, its use in particle physics phenomenology has been hindered by the abscence of a reliable way to estimate that error. The standard Monte Carlo error estimator relies on the assumption that the points are generated independently of each other and, therefore, fails to account for the error improvement advertised by the Quasi-Monte Carlo method. We advocate the construction o...

  15. An introduction to Monte Carlo methods

    NARCIS (Netherlands)

    Walter, J. -C.; Barkema, G. T.

    2015-01-01

    Monte Carlo simulations are methods for simulating statistical systems. The aim is to generate a representative ensemble of configurations to access thermodynamical quantities without the need to solve the system analytically or to perform an exact enumeration. The main principles of Monte Carlo sim

  16. Challenges of Monte Carlo Transport

    Energy Technology Data Exchange (ETDEWEB)

    Long, Alex Roberts [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-10

    These are slides from a presentation for Parallel Summer School at Los Alamos National Laboratory. Solving discretized partial differential equations (PDEs) of interest can require a large number of computations. We can identify concurrency to allow parallel solution of discrete PDEs. Simulated particles histories can be used to solve the Boltzmann transport equation. Particle histories are independent in neutral particle transport, making them amenable to parallel computation. Physical parameters and method type determine the data dependencies of particle histories. Data requirements shape parallel algorithms for Monte Carlo. Then, Parallel Computational Physics and Parallel Monte Carlo are discussed and, finally, the results are given. The mesh passing method greatly simplifies the IMC implementation and allows simple load-balancing. Using MPI windows and passive, one-sided RMA further simplifies the implementation by removing target synchronization. The author is very interested in implementations of PGAS that may allow further optimization for one-sided, read-only memory access (e.g. Open SHMEM). The MPICH_RMA_OVER_DMAPP option and library is required to make one-sided messaging scale on Trinitite - Moonlight scales poorly. Interconnect specific libraries or functions are likely necessary to ensure performance. BRANSON has been used to directly compare the current standard method to a proposed method on idealized problems. The mesh passing algorithm performs well on problems that are designed to show the scalability of the particle passing method. BRANSON can now run load-imbalanced, dynamic problems. Potential avenues of improvement in the mesh passing algorithm will be implemented and explored. A suite of test problems that stress DD methods will elucidate a possible path forward for production codes.

  17. Monte Carlo analysis of radiative transport in oceanographic lidar measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cupini, E.; Ferro, G. [ENEA, Divisione Fisica Applicata, Centro Ricerche Ezio Clementel, Bologna (Italy); Ferrari, N. [Bologna Univ., Bologna (Italy). Dipt. Ingegneria Energetica, Nucleare e del Controllo Ambientale

    2001-07-01

    The analysis of oceanographic lidar systems measurements is often carried out with semi-empirical methods, since there is only a rough understanding of the effects of many environmental variables. The development of techniques for interpreting the accuracy of lidar measurements is needed to evaluate the effects of various environmental situations, as well as of different experimental geometric configurations and boundary conditions. A Monte Carlo simulation model represents a tool that is particularly well suited for answering these important questions. The PREMAR-2F Monte Carlo code has been developed taking into account the main molecular and non-molecular components of the marine environment. The laser radiation interaction processes of diffusion, re-emission, refraction and absorption are treated. In particular are considered: the Rayleigh elastic scattering, produced by atoms and molecules with small dimensions with respect to the laser emission wavelength (i.e. water molecules), the Mie elastic scattering, arising from atoms or molecules with dimensions comparable to the laser wavelength (hydrosols), the Raman inelastic scattering, typical of water, the absorption of water, inorganic (sediments) and organic (phytoplankton and CDOM) hydrosols, the fluorescence re-emission of chlorophyll and yellow substances. PREMAR-2F is an extension of a code for the simulation of the radiative transport in atmospheric environments (PREMAR-2). The approach followed in PREMAR-2 was to combine conventional Monte Carlo techniques with analytical estimates of the probability of the receiver to have a contribution from photons coming back after an interaction in the field of view of the lidar fluorosensor collecting apparatus. This offers an effective mean for modelling a lidar system with realistic geometric constraints. The retrieved semianalytic Monte Carlo radiative transfer model has been developed in the frame of the Italian Research Program for Antarctica (PNRA) and it is

  18. Ceramiche prenuragiche dal Lotto 46A di Monte Olladiri in Monastir (CA

    Directory of Open Access Journals (Sweden)

    Alessandro Mascia

    2012-06-01

    Full Text Available Dopo aver descritto brevemente le caratteristiche geomorfologiche, le risorse economiche e la storia degli studi del noto sito di monte Olladiri di Monastir (Cagliari, l’autore di questo contributo ne traccia le vicende culturali. In seguito presenta lo studio di una selezione di ceramiche di età neolitica ed eneolitica, dalla facies di San Ciriaco, la più antica attestazione, finora, della presenza umana nel sito, prosegue poi con la cultura di Ozieri e con quella di Monte Claro, periodi nei quali il sito raggiunse la massima espansione. Tra le due età vi sono anche scarse testimonianze del periodo Sub-Ozieri. After a short description of the geo-morphological features, economic resources and history of studies of well-known site of Monte Olladiri in Monastir (Cagliari, the author of this article sketches out the life and cultural lifetime of this place. Then, he presents the study of a selection of neolitic and eneolitic potteries, from San Ciriaco culture, the most ancient testimonial, till now, of the human presence in the site, then he goes on, with Ozieri and Monte-Claro cultures, periods when the site achieves greatest expansion. Between the two periods there are not many traces of Sub-Ozieri period.

  19. Cambios en el uso del suelo y deforestación en el sur de los estados de Campeche y Quintana Roo, México

    Directory of Open Access Journals (Sweden)

    Sergio Cortina Villar

    1999-01-01

    Full Text Available Mediate la interpretacion de imágenes LANDSAT MSS se examina que proporción de la superficie de selvas y sabanas fue transformadas en áreas agricolas y ganaderas, entre 1975 y 1990, en viejos y nuevos ejidos ubicados a lo largo de la carretera Escárcega- Chetumal. en los años setenta, estos ejidos fueron objeto de un programa e colonizacion dirigida financiado por el gobierno federal, proceso que incluyó el desmote de las selvas para establecer áreas agrícolas y ganderas modernas. Contra la idea de que la mayor parte de las selvas habian sido destruidas, los resultados indican que, al término el periodo estudiado, un 25% de las selvas del área en estudio habian sido desmontadas y un 43% de la superficie desmontada habia dejado d utilizarse en la produccion agropecuaria y estba cubierta por vegetacion secundaria arbustiva o arbórea

  20. Montes de Piedad eclesiásticos y particulares (S. XVIII-XIX: Usos monetarios

    Directory of Open Access Journals (Sweden)

    Muñoz Serrulla, María Teresa

    2009-12-01

    fronteras llegará a otras zonas europeas, entre ellas a la Península Ibérica. En el seno de la monarquía hispana en los inicios del siglo XVIII tiene lugar la fundación del Monte de Piedad de Madrid, obra del Padre Piquer que será heredero del espíritu y objetivos de los primitivos Montes italianos incluirá algunas novedades fruto de la devoción de su fundador y de las características propias de la época. Este Monte se constituye a su vez en modelo de otras instituciones similares tanto en la península como en los virreinatos americanos. Con el paso del tiempo, se producen una serie de fundaciones que coinciden en la denominación (todas llevarán por nombre Monte de Piedad, pero con importantes diferencias en sus constituciones y fines. Estas fundaciones surgen tanto en ámbito eclesiástico, como secular. El análisis de alguna de estas instituciones es el objetivo del presente estudio, diferenciando fundaciones eclesiásticas y seculares (en estas últimas se distinguen las fundadas por miembros de la nobleza. Partiendo de los textos fundacionales se analizan los objetivos particulares o generales, su espíritu benéfico, y diferentes aspectos relacionados con su puesta en marcha, pleitos, utilización para fines diferentes de los señalados en su fundación, etc.

  1. Lattice gauge theories and Monte Carlo simulations

    CERN Document Server

    Rebbi, Claudio

    1983-01-01

    This volume is the most up-to-date review on Lattice Gauge Theories and Monte Carlo Simulations. It consists of two parts. Part one is an introductory lecture on the lattice gauge theories in general, Monte Carlo techniques and on the results to date. Part two consists of important original papers in this field. These selected reprints involve the following: Lattice Gauge Theories, General Formalism and Expansion Techniques, Monte Carlo Simulations. Phase Structures, Observables in Pure Gauge Theories, Systems with Bosonic Matter Fields, Simulation of Systems with Fermions.

  2. Fast quantum Monte Carlo on a GPU

    CERN Document Server

    Lutsyshyn, Y

    2013-01-01

    We present a scheme for the parallelization of quantum Monte Carlo on graphical processing units, focusing on bosonic systems and variational Monte Carlo. We use asynchronous execution schemes with shared memory persistence, and obtain an excellent acceleration. Comparing with single core execution, GPU-accelerated code runs over x100 faster. The CUDA code is provided along with the package that is necessary to execute variational Monte Carlo for a system representing liquid helium-4. The program was benchmarked on several models of Nvidia GPU, including Fermi GTX560 and M2090, and the latest Kepler architecture K20 GPU. Kepler-specific optimization is discussed.

  3. Monte carlo simulation for soot dynamics

    KAUST Repository

    Zhou, Kun

    2012-01-01

    A new Monte Carlo method termed Comb-like frame Monte Carlo is developed to simulate the soot dynamics. Detailed stochastic error analysis is provided. Comb-like frame Monte Carlo is coupled with the gas phase solver Chemkin II to simulate soot formation in a 1-D premixed burner stabilized flame. The simulated soot number density, volume fraction, and particle size distribution all agree well with the measurement available in literature. The origin of the bimodal distribution of particle size distribution is revealed with quantitative proof.

  4. Monte Carlo approaches to light nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J.

    1990-01-01

    Significant progress has been made recently in the application of Monte Carlo methods to the study of light nuclei. We review new Green's function Monte Carlo results for the alpha particle, Variational Monte Carlo studies of {sup 16}O, and methods for low-energy scattering and transitions. Through these calculations, a coherent picture of the structure and electromagnetic properties of light nuclei has arisen. In particular, we examine the effect of the three-nucleon interaction and the importance of exchange currents in a variety of experimentally measured properties, including form factors and capture cross sections. 29 refs., 7 figs.

  5. Metodología para la evaluación del potencial insecticida de especies forestales.

    Directory of Open Access Journals (Sweden)

    Morales Soto León

    2000-06-01

    Full Text Available La diversidad florística de Colombia plantea enormes retos de investigación, con miras a una utilización racional e integral de sus recursos forestales. Las plantas con efectos biocidas utilizables en el control de plagas o enfermedades revisten una singular importancia. El objetivo de este trabajo es plantear una metodología de fácil aplicación, bajo costo y rápidos resultados, que permita acopiar la información necesaria sobre el mayor número de especies con potencial en este sentido. La metodología plantea la siguiente secuencia: selección de las especies vegetales de interés, apoyada en los reportes bibliográficos, conocimiento ancestral y observaciones personales; recolección del material en el campo; preparación del extracto total a partir del material seco; pruebas iniciales con Artemia salina Lech. para detectar actividad biológica, a través de la determinación de la LC50 (las especies con LC50 menores de 1000 ppm se consideran promisorias y ameritan procesos posteriores de fraccionamiento químico, bioensayos con las sustancias más promisorias sobre algún organismo de interés particular y determinación final de los compuestos activos en la planta. La metodología descrita fue empleada en la evaluación del potencial de acción biocida de 5 especies arbóreas o arbustivas, Guarea guidonia (L. Sleumer y Trichia hirta L. (Meliaceae, Machaerium moritzianum Benth. (Fabaceae, Swinglea glutinosa Merrill. (Rutaceae y Mammea americana L. (Clusiaceae. Se utilizó para los bioensayos iniciales el microcrustáceo Artemia salina Leach como indicador del potencial biocida con el fin de seleccionar las dos especies más promisorias a partir de las LC50 obtenidas. Con las dos se realizaron los bioensayos para evaluar la acción fagoinhibidora en la hormiga arriera Atta cephalotes (L., y el posible control de Alconeura sp. (Homoptera: Cicadellidae, insecto chupador que afecta la ceiba verde Pseudobombax septenatum (Jacq. Dugand

  6. 11th International Conference on Monte Carlo and Quasi-Monte Carlo Methods in Scientific Computing

    CERN Document Server

    Nuyens, Dirk

    2016-01-01

    This book presents the refereed proceedings of the Eleventh International Conference on Monte Carlo and Quasi-Monte Carlo Methods in Scientific Computing that was held at the University of Leuven (Belgium) in April 2014. These biennial conferences are major events for Monte Carlo and quasi-Monte Carlo researchers. The proceedings include articles based on invited lectures as well as carefully selected contributed papers on all theoretical aspects and applications of Monte Carlo and quasi-Monte Carlo methods. Offering information on the latest developments in these very active areas, this book is an excellent reference resource for theoreticians and practitioners interested in solving high-dimensional computational problems, arising, in particular, in finance, statistics and computer graphics.

  7. Monte Carlo simulations for plasma physics

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, M.; Murakami, S.; Nakajima, N.; Wang, W.X. [National Inst. for Fusion Science, Toki, Gifu (Japan)

    2000-07-01

    Plasma behaviours are very complicated and the analyses are generally difficult. However, when the collisional processes play an important role in the plasma behaviour, the Monte Carlo method is often employed as a useful tool. For examples, in neutral particle injection heating (NBI heating), electron or ion cyclotron heating, and alpha heating, Coulomb collisions slow down high energetic particles and pitch angle scatter them. These processes are often studied by the Monte Carlo technique and good agreements can be obtained with the experimental results. Recently, Monte Carlo Method has been developed to study fast particle transports associated with heating and generating the radial electric field. Further it is applied to investigating the neoclassical transport in the plasma with steep gradients of density and temperatures which is beyong the conventional neoclassical theory. In this report, we briefly summarize the researches done by the present authors utilizing the Monte Carlo method. (author)

  8. Monte Vista NWR Water Use Report- 1964

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes water use at Monte Vista NWR for 1964. The document includes summaries of 1964 water use, 1965 water program recommendations, and proposed...

  9. Improved Monte Carlo Renormalization Group Method

    Science.gov (United States)

    Gupta, R.; Wilson, K. G.; Umrigar, C.

    1985-01-01

    An extensive program to analyze critical systems using an Improved Monte Carlo Renormalization Group Method (IMCRG) being undertaken at LANL and Cornell is described. Here we first briefly review the method and then list some of the topics being investigated.

  10. Simulation and the Monte Carlo method

    CERN Document Server

    Rubinstein, Reuven Y

    2016-01-01

    Simulation and the Monte Carlo Method, Third Edition reflects the latest developments in the field and presents a fully updated and comprehensive account of the major topics that have emerged in Monte Carlo simulation since the publication of the classic First Edition over more than a quarter of a century ago. While maintaining its accessible and intuitive approach, this revised edition features a wealth of up-to-date information that facilitates a deeper understanding of problem solving across a wide array of subject areas, such as engineering, statistics, computer science, mathematics, and the physical and life sciences. The book begins with a modernized introduction that addresses the basic concepts of probability, Markov processes, and convex optimization. Subsequent chapters discuss the dramatic changes that have occurred in the field of the Monte Carlo method, with coverage of many modern topics including: Markov Chain Monte Carlo, variance reduction techniques such as the transform likelihood ratio...

  11. Avariide kiuste Monte Carlosse / Aare Arula

    Index Scriptorium Estoniae

    Arula, Aare

    2007-01-01

    Vt. ka Tehnika dlja Vsehh nr. 3, lk. 26-27. 26. jaanuaril 1937 Tallinnast Monte Carlo tähesõidule startinud Karl Siitanit ja tema meeskonda ootasid ees seiklused, mis oleksid neile peaaegu elu maksnud

  12. Smart detectors for Monte Carlo radiative transfer

    CERN Document Server

    Baes, Maarten

    2008-01-01

    Many optimization techniques have been invented to reduce the noise that is inherent in Monte Carlo radiative transfer simulations. As the typical detectors used in Monte Carlo simulations do not take into account all the information contained in the impacting photon packages, there is still room to optimize this detection process and the corresponding estimate of the surface brightness distributions. We want to investigate how all the information contained in the distribution of impacting photon packages can be optimally used to decrease the noise in the surface brightness distributions and hence to increase the efficiency of Monte Carlo radiative transfer simulations. We demonstrate that the estimate of the surface brightness distribution in a Monte Carlo radiative transfer simulation is similar to the estimate of the density distribution in an SPH simulation. Based on this similarity, a recipe is constructed for smart detectors that take full advantage of the exact location of the impact of the photon pack...

  13. Monte Carlo methods for particle transport

    CERN Document Server

    Haghighat, Alireza

    2015-01-01

    The Monte Carlo method has become the de facto standard in radiation transport. Although powerful, if not understood and used appropriately, the method can give misleading results. Monte Carlo Methods for Particle Transport teaches appropriate use of the Monte Carlo method, explaining the method's fundamental concepts as well as its limitations. Concise yet comprehensive, this well-organized text: * Introduces the particle importance equation and its use for variance reduction * Describes general and particle-transport-specific variance reduction techniques * Presents particle transport eigenvalue issues and methodologies to address these issues * Explores advanced formulations based on the author's research activities * Discusses parallel processing concepts and factors affecting parallel performance Featuring illustrative examples, mathematical derivations, computer algorithms, and homework problems, Monte Carlo Methods for Particle Transport provides nuclear engineers and scientists with a practical guide ...

  14. Quantum Monte Carlo Calculations of Light Nuclei

    CERN Document Server

    Pieper, Steven C

    2007-01-01

    During the last 15 years, there has been much progress in defining the nuclear Hamiltonian and applying quantum Monte Carlo methods to the calculation of light nuclei. I describe both aspects of this work and some recent results.

  15. Aasta film - joonisfilm "Mont Blanc" / Verni Leivak

    Index Scriptorium Estoniae

    Leivak, Verni, 1966-

    2002-01-01

    Eesti Filmiajakirjanike Ühing andis aasta 2001 parima filmi tiitli Priit Tenderi joonisfilmile "Mont Blanc" : Eesti Joonisfilm 2001.Ka filmikriitikute eelistused kinodes ja televisioonis 2001. aastal näidatud filmide osas

  16. Pheasant hunting on the Monte Vista NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This letter to the Alamosa/Monte Vista NWR Refuge Manager discusses the need to alter management of pheasants in the area to halt the continued decline in population...

  17. Monte Carlo Hamiltonian:Inverse Potential

    Institute of Scientific and Technical Information of China (English)

    LUO Xiang-Qian; CHENG Xiao-Ni; Helmut KR(O)GER

    2004-01-01

    The Monte Carlo Hamiltonian method developed recently allows to investigate the ground state and low-lying excited states of a quantum system,using Monte Carlo(MC)algorithm with importance sampling.However,conventional MC algorithm has some difficulties when applied to inverse potentials.We propose to use effective potential and extrapolation method to solve the problem.We present examples from the hydrogen system.

  18. The Feynman Path Goes Monte Carlo

    OpenAIRE

    Sauer, Tilman

    2001-01-01

    Path integral Monte Carlo (PIMC) simulations have become an important tool for the investigation of the statistical mechanics of quantum systems. I discuss some of the history of applying the Monte Carlo method to non-relativistic quantum systems in path-integral representation. The principle feasibility of the method was well established by the early eighties, a number of algorithmic improvements have been introduced in the last two decades.

  19. Self-consistent kinetic lattice Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Horsfield, A.; Dunham, S.; Fujitani, Hideaki

    1999-07-01

    The authors present a brief description of a formalism for modeling point defect diffusion in crystalline systems using a Monte Carlo technique. The main approximations required to construct a practical scheme are briefly discussed, with special emphasis on the proper treatment of charged dopants and defects. This is followed by tight binding calculations of the diffusion barrier heights for charged vacancies. Finally, an application of the kinetic lattice Monte Carlo method to vacancy diffusion is presented.

  20. Monte Carlo Algorithms for Linear Problems

    OpenAIRE

    DIMOV, Ivan

    2000-01-01

    MSC Subject Classification: 65C05, 65U05. Monte Carlo methods are a powerful tool in many fields of mathematics, physics and engineering. It is known, that these methods give statistical estimates for the functional of the solution by performing random sampling of a certain chance variable whose mathematical expectation is the desired functional. Monte Carlo methods are methods for solving problems using random variables. In the book [16] edited by Yu. A. Shreider one can find the followin...

  1. Error in Monte Carlo, quasi-error in Quasi-Monte Carlo

    CERN Document Server

    Kleiss, R H

    2006-01-01

    While the Quasi-Monte Carlo method of numerical integration achieves smaller integration error than standard Monte Carlo, its use in particle physics phenomenology has been hindered by the abscence of a reliable way to estimate that error. The standard Monte Carlo error estimator relies on the assumption that the points are generated independently of each other and, therefore, fails to account for the error improvement advertised by the Quasi-Monte Carlo method. We advocate the construction of an estimator of stochastic nature, based on the ensemble of pointsets with a particular discrepancy value. We investigate the consequences of this choice and give some first empirical results on the suggested estimators.

  2. Monte Carlo EM加速算法%Acceleration of Monte Carlo EM Algorithm

    Institute of Scientific and Technical Information of China (English)

    罗季

    2008-01-01

    EM算法是近年来常用的求后验众数的估计的一种数据增广算法,但由于求出其E步中积分的显示表达式有时很困难,甚至不可能,限制了其应用的广泛性.而Monte Carlo EM算法很好地解决了这个问题,将EM算法中E步的积分用Monte Carlo模拟来有效实现,使其适用性大大增强.但无论是EM算法,还是Monte Carlo EM算法,其收敛速度都是线性的,被缺损信息的倒数所控制,当缺损数据的比例很高时,收敛速度就非常缓慢.而Newton-Raphson算法在后验众数的附近具有二次收敛速率.本文提出Monte Carlo EM加速算法,将Monte Carlo EM算法与Newton-Raphson算法结合,既使得EM算法中的E步用Monte Carlo模拟得以实现,又证明了该算法在后验众数附近具有二次收敛速度.从而使其保留了Monte Carlo EM算法的优点,并改进了Monte Carlo EM算法的收敛速度.本文通过数值例子,将Monte Carlo EM加速算法的结果与EM算法、Monte Carlo EM算法的结果进行比较,进一步说明了Monte Carlo EM加速算法的优良性.

  3. Tafonomia y ambiente sedimentario del yacimiento de Huelago

    Directory of Open Access Journals (Sweden)

    Alberdi, M. T.

    2002-04-01

    situ. En los niveles detríticos asociados a paleocanales hay un porcentaje mayor de dientes aislados y esquirlas; y las mandíbulas y cuernas están asociadas a niveles limoso-margosos sin removilizar. Los agentes atmosféricos contribuyeron activamente a la fracturación de los huesos. La actividad de carroñeros-predadores en la superficie herbácea y encharcada del borde del lago ha sido reconocida. La gran diversidad de rumiantes, en particular los ramoneadores, indica áreas arboladas o arbustivas en los alrededores de Huélago, aunque no en el área inmediata del borde del lago. Se elaboró una matriz de datos con las variables medidas en cada resto fósil recuperado, que fue la base para el tratamiento gráfico y estadístico utilizado en el estudio del yacimiento.

  4. Approaching Chemical Accuracy with Quantum Monte Carlo

    CERN Document Server

    Petruzielo, F R; Umrigar, C J

    2012-01-01

    A quantum Monte Carlo study of the atomization energies for the G2 set of molecules is presented. Basis size dependence of diffusion Monte Carlo atomization energies is studied with a single determinant Slater-Jastrow trial wavefunction formed from Hartree-Fock orbitals. With the largest basis set, the mean absolute deviation from experimental atomization energies for the G2 set is 3.0 kcal/mol. Optimizing the orbitals within variational Monte Carlo improves the agreement between diffusion Monte Carlo and experiment, reducing the mean absolute deviation to 2.1 kcal/mol. Moving beyond a single determinant Slater-Jastrow trial wavefunction, diffusion Monte Carlo with a small complete active space Slater-Jastrow trial wavefunction results in near chemical accuracy. In this case, the mean absolute deviation from experimental atomization energies is 1.2 kcal/mol. It is shown from calculations on systems containing phosphorus that the accuracy can be further improved by employing a larger active space.

  5. Quantum Monte Carlo with Variable Spins

    CERN Document Server

    Melton, Cody A; Mitas, Lubos

    2016-01-01

    We investigate the inclusion of variable spins in electronic structure quantum Monte Carlo, with a focus on diffusion Monte Carlo with Hamiltonians that include spin-orbit interactions. Following our previous introduction of fixed-phase spin-orbit diffusion Monte Carlo (FPSODMC), we thoroughly discuss the details of the method and elaborate upon its technicalities. We present a proof for an upper-bound property for complex nonlocal operators, which allows for the implementation of T-moves to ensure the variational property. We discuss the time step biases associated with our particular choice of spin representation. Applications of the method are also presented for atomic and molecular systems. We calculate the binding energies and geometry of the PbH and Sn$_2$ molecules, as well as the electron affinities of the 6$p$ row elements in close agreement with experiments.

  6. Quantum speedup of Monte Carlo methods.

    Science.gov (United States)

    Montanaro, Ashley

    2015-09-08

    Monte Carlo methods use random sampling to estimate numerical quantities which are hard to compute deterministically. One important example is the use in statistical physics of rapidly mixing Markov chains to approximately compute partition functions. In this work, we describe a quantum algorithm which can accelerate Monte Carlo methods in a very general setting. The algorithm estimates the expected output value of an arbitrary randomized or quantum subroutine with bounded variance, achieving a near-quadratic speedup over the best possible classical algorithm. Combining the algorithm with the use of quantum walks gives a quantum speedup of the fastest known classical algorithms with rigorous performance bounds for computing partition functions, which use multiple-stage Markov chain Monte Carlo techniques. The quantum algorithm can also be used to estimate the total variation distance between probability distributions efficiently.

  7. Adiabatic optimization versus diffusion Monte Carlo methods

    Science.gov (United States)

    Jarret, Michael; Jordan, Stephen P.; Lackey, Brad

    2016-10-01

    Most experimental and theoretical studies of adiabatic optimization use stoquastic Hamiltonians, whose ground states are expressible using only real nonnegative amplitudes. This raises a question as to whether classical Monte Carlo methods can simulate stoquastic adiabatic algorithms with polynomial overhead. Here we analyze diffusion Monte Carlo algorithms. We argue that, based on differences between L1 and L2 normalized states, these algorithms suffer from certain obstructions preventing them from efficiently simulating stoquastic adiabatic evolution in generality. In practice however, we obtain good performance by introducing a method that we call Substochastic Monte Carlo. In fact, our simulations are good classical optimization algorithms in their own right, competitive with the best previously known heuristic solvers for MAX-k -SAT at k =2 ,3 ,4 .

  8. Random Numbers and Monte Carlo Methods

    Science.gov (United States)

    Scherer, Philipp O. J.

    Many-body problems often involve the calculation of integrals of very high dimension which cannot be treated by standard methods. For the calculation of thermodynamic averages Monte Carlo methods are very useful which sample the integration volume at randomly chosen points. After summarizing some basic statistics, we discuss algorithms for the generation of pseudo-random numbers with given probability distribution which are essential for all Monte Carlo methods. We show how the efficiency of Monte Carlo integration can be improved by sampling preferentially the important configurations. Finally the famous Metropolis algorithm is applied to classical many-particle systems. Computer experiments visualize the central limit theorem and apply the Metropolis method to the traveling salesman problem.

  9. CosmoPMC: Cosmology Population Monte Carlo

    CERN Document Server

    Kilbinger, Martin; Cappe, Olivier; Cardoso, Jean-Francois; Fort, Gersende; Prunet, Simon; Robert, Christian P; Wraith, Darren

    2011-01-01

    We present the public release of the Bayesian sampling algorithm for cosmology, CosmoPMC (Cosmology Population Monte Carlo). CosmoPMC explores the parameter space of various cosmological probes, and also provides a robust estimate of the Bayesian evidence. CosmoPMC is based on an adaptive importance sampling method called Population Monte Carlo (PMC). Various cosmology likelihood modules are implemented, and new modules can be added easily. The importance-sampling algorithm is written in C, and fully parallelised using the Message Passing Interface (MPI). Due to very little overhead, the wall-clock time required for sampling scales approximately with the number of CPUs. The CosmoPMC package contains post-processing and plotting programs, and in addition a Monte-Carlo Markov chain (MCMC) algorithm. The sampling engine is implemented in the library pmclib, and can be used independently. The software is available for download at http://www.cosmopmc.info.

  10. Shell model the Monte Carlo way

    Energy Technology Data Exchange (ETDEWEB)

    Ormand, W.E.

    1995-03-01

    The formalism for the auxiliary-field Monte Carlo approach to the nuclear shell model is presented. The method is based on a linearization of the two-body part of the Hamiltonian in an imaginary-time propagator using the Hubbard-Stratonovich transformation. The foundation of the method, as applied to the nuclear many-body problem, is discussed. Topics presented in detail include: (1) the density-density formulation of the method, (2) computation of the overlaps, (3) the sign of the Monte Carlo weight function, (4) techniques for performing Monte Carlo sampling, and (5) the reconstruction of response functions from an imaginary-time auto-correlation function using MaxEnt techniques. Results obtained using schematic interactions, which have no sign problem, are presented to demonstrate the feasibility of the method, while an extrapolation method for realistic Hamiltonians is presented. In addition, applications at finite temperature are outlined.

  11. Monte Carlo strategies in scientific computing

    CERN Document Server

    Liu, Jun S

    2008-01-01

    This paperback edition is a reprint of the 2001 Springer edition This book provides a self-contained and up-to-date treatment of the Monte Carlo method and develops a common framework under which various Monte Carlo techniques can be "standardized" and compared Given the interdisciplinary nature of the topics and a moderate prerequisite for the reader, this book should be of interest to a broad audience of quantitative researchers such as computational biologists, computer scientists, econometricians, engineers, probabilists, and statisticians It can also be used as the textbook for a graduate-level course on Monte Carlo methods Many problems discussed in the alter chapters can be potential thesis topics for masters’ or PhD students in statistics or computer science departments Jun Liu is Professor of Statistics at Harvard University, with a courtesy Professor appointment at Harvard Biostatistics Department Professor Liu was the recipient of the 2002 COPSS Presidents' Award, the most prestigious one for sta...

  12. Monte Carlo simulation of neutron scattering instruments

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, P.A.

    1995-12-31

    A library of Monte Carlo subroutines has been developed for the purpose of design of neutron scattering instruments. Using small-angle scattering as an example, the philosophy and structure of the library are described and the programs are used to compare instruments at continuous wave (CW) and long-pulse spallation source (LPSS) neutron facilities. The Monte Carlo results give a count-rate gain of a factor between 2 and 4 using time-of-flight analysis. This is comparable to scaling arguments based on the ratio of wavelength bandwidth to resolution width.

  13. Monte carlo simulations of organic photovoltaics.

    Science.gov (United States)

    Groves, Chris; Greenham, Neil C

    2014-01-01

    Monte Carlo simulations are a valuable tool to model the generation, separation, and collection of charges in organic photovoltaics where charges move by hopping in a complex nanostructure and Coulomb interactions between charge carriers are important. We review the Monte Carlo techniques that have been applied to this problem, and describe the results of simulations of the various recombination processes that limit device performance. We show how these processes are influenced by the local physical and energetic structure of the material, providing information that is useful for design of efficient photovoltaic systems.

  14. Monte Carlo dose distributions for radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Perucha, M.; Leal, A.; Rincon, M.; Carrasco, E. [Sevilla Univ. (Spain). Dept. Fisiologia Medica y Biofisica; Sanchez-Doblado, F. [Sevilla Univ. (Spain). Dept. Fisiologia Medica y Biofisica]|[Hospital Univ. Virgen Macarena, Sevilla (Spain). Servicio de Oncologia Radioterapica; Nunez, L. [Clinica Puerta de Hierro, Madrid (Spain). Servicio de Radiofisica; Arrans, R.; Sanchez-Calzado, J.A.; Errazquin, L. [Hospital Univ. Virgen Macarena, Sevilla (Spain). Servicio de Oncologia Radioterapica; Sanchez-Nieto, B. [Royal Marsden NHS Trust (United Kingdom). Joint Dept. of Physics]|[Inst. of Cancer Research, Sutton, Surrey (United Kingdom)

    2001-07-01

    The precision of Radiosurgery Treatment planning systems is limited by the approximations of their algorithms and by their dosimetrical input data. This fact is especially important in small fields. However, the Monte Carlo methods is an accurate alternative as it considers every aspect of particle transport. In this work an acoustic neurinoma is studied by comparing the dose distribution of both a planning system and Monte Carlo. Relative shifts have been measured and furthermore, Dose-Volume Histograms have been calculated for target and adjacent organs at risk. (orig.)

  15. The Rational Hybrid Monte Carlo Algorithm

    CERN Document Server

    Clark, M A

    2006-01-01

    The past few years have seen considerable progress in algorithmic development for the generation of gauge fields including the effects of dynamical fermions. The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is performed using a rational approximation in place the usual inverse quark matrix kernel is one of these developments. This algorithm has been found to be extremely beneficial in many areas of lattice QCD (chiral fermions, finite temperature, Wilson fermions etc.). We review the algorithm and some of these benefits, and we compare against other recent algorithm developements. We conclude with an update of the Berlin wall plot comparing costs of all popular fermion formulations.

  16. The Rational Hybrid Monte Carlo algorithm

    Science.gov (United States)

    Clark, Michael

    2006-12-01

    The past few years have seen considerable progress in algorithmic development for the generation of gauge fields including the effects of dynamical fermions. The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is performed using a rational approximation in place the usual inverse quark matrix kernel is one of these developments. This algorithm has been found to be extremely beneficial in many areas of lattice QCD (chiral fermions, finite temperature, Wilson fermions etc.). We review the algorithm and some of these benefits, and we compare against other recent algorithm developements. We conclude with an update of the Berlin wall plot comparing costs of all popular fermion formulations.

  17. Monte Carlo Hamiltonian:Linear Potentials

    Institute of Scientific and Technical Information of China (English)

    LUOXiang-Qian; HelmutKROEGER; 等

    2002-01-01

    We further study the validity of the Monte Carlo Hamiltonian method .The advantage of the method,in comparison with the standard Monte Carlo Lagrangian approach,is its capability to study the excited states.We consider two quantum mechanical models:a symmetric one V(x)=/x/2;and an asymmetric one V(x)==∞,for x<0 and V(x)=2,for x≥0.The results for the spectrum,wave functions and thermodynamical observables are in agreement with the analytical or Runge-Kutta calculations.

  18. Parallel Markov chain Monte Carlo simulations.

    Science.gov (United States)

    Ren, Ruichao; Orkoulas, G

    2007-06-07

    With strict detailed balance, parallel Monte Carlo simulation through domain decomposition cannot be validated with conventional Markov chain theory, which describes an intrinsically serial stochastic process. In this work, the parallel version of Markov chain theory and its role in accelerating Monte Carlo simulations via cluster computing is explored. It is shown that sequential updating is the key to improving efficiency in parallel simulations through domain decomposition. A parallel scheme is proposed to reduce interprocessor communication or synchronization, which slows down parallel simulation with increasing number of processors. Parallel simulation results for the two-dimensional lattice gas model show substantial reduction of simulation time for systems of moderate and large size.

  19. Fast sequential Monte Carlo methods for counting and optimization

    CERN Document Server

    Rubinstein, Reuven Y; Vaisman, Radislav

    2013-01-01

    A comprehensive account of the theory and application of Monte Carlo methods Based on years of research in efficient Monte Carlo methods for estimation of rare-event probabilities, counting problems, and combinatorial optimization, Fast Sequential Monte Carlo Methods for Counting and Optimization is a complete illustration of fast sequential Monte Carlo techniques. The book provides an accessible overview of current work in the field of Monte Carlo methods, specifically sequential Monte Carlo techniques, for solving abstract counting and optimization problems. Written by authorities in the

  20. Monte Carlo methods in AB initio quantum chemistry quantum Monte Carlo for molecules

    CERN Document Server

    Lester, William A; Reynolds, PJ

    1994-01-01

    This book presents the basic theory and application of the Monte Carlo method to the electronic structure of atoms and molecules. It assumes no previous knowledge of the subject, only a knowledge of molecular quantum mechanics at the first-year graduate level. A working knowledge of traditional ab initio quantum chemistry is helpful, but not essential.Some distinguishing features of this book are: Clear exposition of the basic theory at a level to facilitate independent study. Discussion of the various versions of the theory: diffusion Monte Carlo, Green's function Monte Carlo, and release n

  1. On the use of stochastic approximation Monte Carlo for Monte Carlo integration

    KAUST Repository

    Liang, Faming

    2009-03-01

    The stochastic approximation Monte Carlo (SAMC) algorithm has recently been proposed as a dynamic optimization algorithm in the literature. In this paper, we show in theory that the samples generated by SAMC can be used for Monte Carlo integration via a dynamically weighted estimator by calling some results from the literature of nonhomogeneous Markov chains. Our numerical results indicate that SAMC can yield significant savings over conventional Monte Carlo algorithms, such as the Metropolis-Hastings algorithm, for the problems for which the energy landscape is rugged. © 2008 Elsevier B.V. All rights reserved.

  2. Análisis de dos áreas naturales protegidas en relación con el crecimiento del Área Metropolitana de Xalapa, Veracruz

    Directory of Open Access Journals (Sweden)

    María Gabriela Hernández Rivera

    2015-01-01

    Full Text Available Con el objetivo de analizar la dinámica espa - cio-temporal en cuanto a la relación del hombre con la naturaleza en un contexto urbano, se estudiaron las áreas naturales protegidas “Molino de San Roque” y “Cerro de la Galaxia” en relación con el crecimiento metropolitano de Xalapa, Veracruz, México. El análisis de imágenes aéreas de 1993 a 2009 reveló que 41.8% de Molino de San Roque y 50.7% del Cerro de la Galaxia no mostraron cambio en la densidad y extensión de la vegetación; 12.2 y 26.7%, respectivamente, mostraron cierto crecimiento de la vegetación, mientras que 46 y 22.6%, correspondientemen - te, mostraron disminución en la cubierta arbórea y arbustiva. El análisis micro histórico-geográfico hizo evidente que en el interior de estas áreas, en donde es menor la afluencia de personas, hubo cierta regeneración de la vegetación, mientras que en las periferias se detectó deforestación. La progresiva invasión humana fue la mayor amenaza para estas áreas a lo que se sumó el abandono por parte de las autoridades. La protección efectiva de las áreas naturales protegidas no se logrará si continúan como espacios abandonados, pues ello deriva en la desvinculación de la sociedad con la naturaleza al resultar espacios a los que el ciudadano no tiene derecho para su uso y recreación

  3. Variance Reduction Techniques in Monte Carlo Methods

    NARCIS (Netherlands)

    Kleijnen, Jack P.C.; Ridder, A.A.N.; Rubinstein, R.Y.

    2010-01-01

    Monte Carlo methods are simulation algorithms to estimate a numerical quantity in a statistical model of a real system. These algorithms are executed by computer programs. Variance reduction techniques (VRT) are needed, even though computer speed has been increasing dramatically, ever since the intr

  4. Monte Carlo methods beyond detailed balance

    NARCIS (Netherlands)

    Schram, Raoul D.; Barkema, Gerard T.

    2015-01-01

    Monte Carlo algorithms are nearly always based on the concept of detailed balance and ergodicity. In this paper we focus on algorithms that do not satisfy detailed balance. We introduce a general method for designing non-detailed balance algorithms, starting from a conventional algorithm satisfying

  5. A comparison of Monte Carlo generators

    CERN Document Server

    Golan, Tomasz

    2014-01-01

    A comparison of GENIE, NEUT, NUANCE, and NuWro Monte Carlo neutrino event generators is presented using a set of four observables: protons multiplicity, total visible energy, most energetic proton momentum, and $\\pi^+$ two-dimensional energy vs cosine distribution.

  6. Scalable Domain Decomposed Monte Carlo Particle Transport

    Energy Technology Data Exchange (ETDEWEB)

    O' Brien, Matthew Joseph [Univ. of California, Davis, CA (United States)

    2013-12-05

    In this dissertation, we present the parallel algorithms necessary to run domain decomposed Monte Carlo particle transport on large numbers of processors (millions of processors). Previous algorithms were not scalable, and the parallel overhead became more computationally costly than the numerical simulation.

  7. Monte Carlo Simulation of Counting Experiments.

    Science.gov (United States)

    Ogden, Philip M.

    A computer program to perform a Monte Carlo simulation of counting experiments was written. The program was based on a mathematical derivation which started with counts in a time interval. The time interval was subdivided to form a binomial distribution with no two counts in the same subinterval. Then the number of subintervals was extended to…

  8. Potencial del Agua del suelo

    Directory of Open Access Journals (Sweden)

    Bustamante Heliodoro

    1986-12-01

    Full Text Available La energía potencial del agua presenta diferencias de un punto del suelo a otro; esas diferencias son las que originan el movimiento del agua de acuerdo a la tendencia universal de la materia en el sentido de moverse de donde la energía potencial es mayor a donde dicha energía es menor. En el suelo el agua en consecuencia se mueve hacia donde su energía decrece hasta lograr su estado de equilibrio. Se desprende entonces que la cantidad de energía potencial absoluta contenida en el agua, no es importante por sí misma, sino por su relación con la energía en diferentes lugares dentro del suelo. El concepto Potencial de agua del suelo es un criterio para esta energía.

  9. Escenarios Monte Carlo para estrategias con expectativas de baja volatilidad cambiante mediante opciones europeas de compra y venta / Monte Carlo scenarios for strategies with expectations of changing low volatility using European call and put options

    OpenAIRE

    2015-01-01

    En este trabajo se generan estrategias especulativas en volatilidad con opciones europeas sobre veintiún componentes del Índice de Precios y Cotizaciones (IPC) y sobre este mismo índice, bajo el supuesto de que la volatilidad del activo subyacente es conducida por un proceso GARCH-M (1,1) calibrado con datos históricos, el precio de la opción se obtiene por simulación Monte Carlo. Con las estrategias de volatilidad construidas con los precios de las opciones simuladas se determinó que la estr...

  10. A Benchmark Approach of Counterparty Credit Exposure of Bermudan Option under Lévy Process: The Monte Carlo-COS Method

    NARCIS (Netherlands)

    Shen, Y.; Van der Weide, J.A.M.; Anderluh, J.H.M.

    2013-01-01

    An advanced method, which we call Monte Carlo-COS method, is proposed for computing the counterparty credit exposure profile of Bermudan options under Lévy process. The different exposure profiles and exercise intensity under different mea- sures, P and Q, are discussed. Since the COS method [1] del

  11. Monte Carlo radiation transport in external beam radiotherapy

    OpenAIRE

    Çeçen, Yiğit

    2013-01-01

    The use of Monte Carlo in radiation transport is an effective way to predict absorbed dose distributions. Monte Carlo modeling has contributed to a better understanding of photon and electron transport by radiotherapy physicists. The aim of this review is to introduce Monte Carlo as a powerful radiation transport tool. In this review, photon and electron transport algorithms for Monte Carlo techniques are investigated and a clinical linear accelerator model is studied for external beam radiot...

  12. Tierras, montes y aguas: Apuntes sobre energía, medio ambiente y justicia en las Américas

    OpenAIRE

    Soluri, John

    2012-01-01

    Resumen El título de este ensayo adopta las palabras del Plan de Ayala (1911) por medio del cual las fuerzas de Emiliano Zapata declararon su concepto de justicia durante la Revolución Mexicana. Desde la revolución hasta la actualidad, distintos historiadores se han dedicado al estudio de conflictos sobre la tierra en América Latina, pero han prestado mucho menos atención a la problemática de las aguas y montes.1 No cabe duda que la tierra ha sido al centro de muchos conflictos históricos y ...

  13. Observaciones sobre chamanismo y el rito del bautismo entre los Ava-Katu-Ete

    OpenAIRE

    Hugo Florencio Centurion Mereles

    2013-01-01

    La cultura Ava-Katu-Ete, los menos estudiados en el Paraguay pero en contraste los que han logrado una mayor compenetración con la sociedad nacional, es una cultura de la palabra. Y como alma y palabra son la misma cosa, al ser producto del contacto con los Dioses, son palabras verdaderas, por eso en el ritual del bautismo es donde el chamán a través de la imposición del nombre del monte que realiza la unión del niño con la naturaleza y, pasa a tener su nombre-alma. En esta cultura centra...

  14. Observaciones sobre chamanismo y el rito del bautismo entre los Ava-Katu-Ete

    OpenAIRE

    Centurion Mereles, Hugo Florencio

    2013-01-01

    La cultura Ava-Katu-Ete, los menos estudiados en el Paraguay pero en contraste los que han logrado una mayor compenetración con la sociedad nacional, es una cultura de la palabra. Y como alma y palabra son la misma cosa, al ser producto del contacto con los Dioses, son palabras verdaderas, por eso en el ritual del bautismo es donde el chamán a través de la imposición del nombre del monte que realiza la unión del niño con la naturaleza y, pasa a tener su nombre-alma.En esta cultura centrada en...

  15. Potencial del agua del suelo

    OpenAIRE

    Bustamante Heliodoro

    2012-01-01

    La energía potencial del agua presenta diferencias de un punto del suelo a otro; esas diferencias son las que originan el movimiento del agua de acuerdo a la tendencia universal de la materia en el sentido de moverse de donde la energía potencial es mayor a donde dicha energía es menor. En el suelo el agua en consecuencia se mueve hacia donde su energía decrece hasta lograr su estado de equilibrio. Se desprende entonces que la cantidad de energía potencial absoluta contenida en el agua, no es...

  16. Simulación y optimización del sistema de ultra alto vacío de una línea experimental del sincrotrón ALBA

    OpenAIRE

    Carballedo Costa, Antonio

    2014-01-01

    El objetivo de este proyecto es dimensionar y optimizar el diseño del sistema de ultra alto vacío (UHV) de la nueva línea experimental de luz infrarroja, de nombre MIRAS, del sincrotrón ALBA. Para ello se utiliza el software MolFlow+, un software que utiliza el principio de Monte Carlo para simular el vacío del objeto de estudio y así obtener los perfiles de presión a lo largo del mismo. En primer lugar, mediante la reproducción con MolFlow+ del sector del anillo de almacenamiento (storage...

  17. Development of advanced geometric models and acceleration techniques for Monte Carlo simulation in Medical Physics

    OpenAIRE

    Badal Soler, Andreu

    2008-01-01

    Els programes de simulació Monte Carlo de caràcter general s'utilitzen actualment en una gran varietat d'aplicacions.Tot i això, els models geomètrics implementats en la majoria de programes imposen certes limitacions a la forma dels objectes que es poden definir. Aquests models no són adequats per descriure les superfícies arbitràries que es troben en estructures anatòmiques o en certs aparells mèdics i, conseqüentment, algunes aplicacions que requereixen l'ús de models geomètrics molt detal...

  18. Impact of Weather Conditions on the Construction of the Terminal - Monte Carlo Simulation

    Directory of Open Access Journals (Sweden)

    Tatjana Stanivuk

    2013-03-01

    Full Text Available A simulation model is developed for the potential planned Patagonia and Tierra del Fuego terminals. The purpose is to identify reliability and availability of loading operations at the terminal. The harsh weather conditions, technical reliability and concurrent traffic affect LNG (Liquefied Natural Gas Carriers during approaching or loading. Probabilistic simulation method is created and Monte Carlo simulations are carried out for several cases, with varied production, number of jetties and terminal storage. The results indicate high importance of weather restrictions and are used to present a recommendation with two loading jetties and a larger volume of storage capacity.

  19. Una alabarda procedente del valle del Manzanares (Madrid

    Directory of Open Access Journals (Sweden)

    Miguel Ángel de BLAS CORTINA

    2009-12-01

    Full Text Available RESUMEN: Se estudia una alabarda metálica procedente —sin datos precisos de su localización— del valle del Manzanares (Madrid. Posiblemente apareciera con otros materiales (¿puntas Palmela?, pero el hecho no pudo ser comprobado. Fundida en un molde monovalvo que proporciona un acabado homogéneo a una sola de las caras, se integra metalúrgicamente en el grupo E 01 (cobres arsenicales propio de la Península Ibérica durante el Calcolítico y el Bronce Antiguo. Tipológicamente puede ser clasificada como integrante del grupo Carrapatas al que pertenecen un conjunto de alabardas procedentes del N.E. de Portugal (Bragança y Tras os Montes del que se conocen escasos testimonios fuera del área característica. Especialmente significativo es el hallazgo de la finca de la Paloma (Pantoja, Toledo que muestra la asociación entre las alabardas Carrapatas y elementos propios del campaniforme tardío de España y Portugal, circunstancia que permite fechar el tipo entre el 1700-1500 a. de J.C., datación similar a las fechas admitidas para las alabardas irlandesas con las que algunos autores ven posibles relaciones. La existencia de alabardas grabadas en estelas más tardías o en rocas al aire libre plantea el problema de su perduración. No obstante, el carácter simbólico de las armas grabadas puede hacer que sea solamente la imagen representada la que superviva, aunque el arma como tal haya perdido vigencia. La alabarda del Manzanares, junto con las de Pantoja, señala la presencia en la Meseta Sur de elementos metalúrgicos propios del N.W. de la Península en un momento sincrónico con las fases finales del campaniforme.ABSTRACT: We study a metallic halberd found in an indeterminate place in the valley of the river Manzanares (Madrid. It might have appeared with other materials (Palmela Points?, although this fact could not be confirmed. Made in a single-faced mould which allows a homogeneous finish to only one of the sides, it belongs from

  20. An enhanced Monte Carlo outlier detection method.

    Science.gov (United States)

    Zhang, Liangxiao; Li, Peiwu; Mao, Jin; Ma, Fei; Ding, Xiaoxia; Zhang, Qi

    2015-09-30

    Outlier detection is crucial in building a highly predictive model. In this study, we proposed an enhanced Monte Carlo outlier detection method by establishing cross-prediction models based on determinate normal samples and analyzing the distribution of prediction errors individually for dubious samples. One simulated and three real datasets were used to illustrate and validate the performance of our method, and the results indicated that this method outperformed Monte Carlo outlier detection in outlier diagnosis. After these outliers were removed, the value of validation by Kovats retention indices and the root mean square error of prediction decreased from 3.195 to 1.655, and the average cross-validation prediction error decreased from 2.0341 to 1.2780. This method helps establish a good model by eliminating outliers. © 2015 Wiley Periodicals, Inc.

  1. Monte Carlo Simulation for Particle Detectors

    CERN Document Server

    Pia, Maria Grazia

    2012-01-01

    Monte Carlo simulation is an essential component of experimental particle physics in all the phases of its life-cycle: the investigation of the physics reach of detector concepts, the design of facilities and detectors, the development and optimization of data reconstruction software, the data analysis for the production of physics results. This note briefly outlines some research topics related to Monte Carlo simulation, that are relevant to future experimental perspectives in particle physics. The focus is on physics aspects: conceptual progress beyond current particle transport schemes, the incorporation of materials science knowledge relevant to novel detection technologies, functionality to model radiation damage, the capability for multi-scale simulation, quantitative validation and uncertainty quantification to determine the predictive power of simulation. The R&D on simulation for future detectors would profit from cooperation within various components of the particle physics community, and synerg...

  2. Multilevel Monte Carlo Approaches for Numerical Homogenization

    KAUST Repository

    Efendiev, Yalchin R.

    2015-10-01

    In this article, we study the application of multilevel Monte Carlo (MLMC) approaches to numerical random homogenization. Our objective is to compute the expectation of some functionals of the homogenized coefficients, or of the homogenized solutions. This is accomplished within MLMC by considering different sizes of representative volumes (RVEs). Many inexpensive computations with the smallest RVE size are combined with fewer expensive computations performed on larger RVEs. Likewise, when it comes to homogenized solutions, different levels of coarse-grid meshes are used to solve the homogenized equation. We show that, by carefully selecting the number of realizations at each level, we can achieve a speed-up in the computations in comparison to a standard Monte Carlo method. Numerical results are presented for both one-dimensional and two-dimensional test-cases that illustrate the efficiency of the approach.

  3. Monte Carlo study of real time dynamics

    CERN Document Server

    Alexandru, Andrei; Bedaque, Paulo F; Vartak, Sohan; Warrington, Neill C

    2016-01-01

    Monte Carlo studies involving real time dynamics are severely restricted by the sign problem that emerges from highly oscillatory phase of the path integral. In this letter, we present a new method to compute real time quantities on the lattice using the Schwinger-Keldysh formalism via Monte Carlo simulations. The key idea is to deform the path integration domain to a complex manifold where the phase oscillations are mild and the sign problem is manageable. We use the previously introduced "contraction algorithm" to create a Markov chain on this alternative manifold. We substantiate our approach by analyzing the quantum mechanical anharmonic oscillator. Our results are in agreement with the exact ones obtained by diagonalization of the Hamiltonian. The method we introduce is generic and in principle applicable to quantum field theory albeit very slow. We discuss some possible improvements that should speed up the algorithm.

  4. Hybrid Monte Carlo with Chaotic Mixing

    CERN Document Server

    Kadakia, Nirag

    2016-01-01

    We propose a hybrid Monte Carlo (HMC) technique applicable to high-dimensional multivariate normal distributions that effectively samples along chaotic trajectories. The method is predicated on the freedom of choice of the HMC momentum distribution, and due to its mixing properties, exhibits sample-to-sample autocorrelations that decay far faster than those in the traditional hybrid Monte Carlo algorithm. We test the methods on distributions of varying correlation structure, finding that the proposed technique produces superior covariance estimates, is less reliant on step-size tuning, and can even function with sparse or no momentum re-sampling. The method presented here is promising for more general distributions, such as those that arise in Bayesian learning of artificial neural networks and in the state and parameter estimation of dynamical systems.

  5. Composite biasing in Monte Carlo radiative transfer

    CERN Document Server

    Baes, Maarten; Lunttila, Tuomas; Bianchi, Simone; Camps, Peter; Juvela, Mika; Kuiper, Rolf

    2016-01-01

    Biasing or importance sampling is a powerful technique in Monte Carlo radiative transfer, and can be applied in different forms to increase the accuracy and efficiency of simulations. One of the drawbacks of the use of biasing is the potential introduction of large weight factors. We discuss a general strategy, composite biasing, to suppress the appearance of large weight factors. We use this composite biasing approach for two different problems faced by current state-of-the-art Monte Carlo radiative transfer codes: the generation of photon packages from multiple components, and the penetration of radiation through high optical depth barriers. In both cases, the implementation of the relevant algorithms is trivial and does not interfere with any other optimisation techniques. Through simple test models, we demonstrate the general applicability, accuracy and efficiency of the composite biasing approach. In particular, for the penetration of high optical depths, the gain in efficiency is spectacular for the spe...

  6. del alcoholismo

    Directory of Open Access Journals (Sweden)

    Rodrigo Arias Duque

    2005-01-01

    Full Text Available Desde el punto de vista farmacológico, es importante comprender qué es el alcohol y cómo actúa en el organismo. No existe una causa simple, sino una interacción complicada de factores neuroquímicos, fisiológicos, psicológicos y sociales que originan y desarrollan esta grave enfermedad fármaco-dependiente. La acción psicofisiológica y farmacodinámica del alcohol es fundamentalmente depresiva, por la reducción de la transmisión sináptica en el sistema nervioso humano. Es un hecho conocido que el consumo excesivo de alcohol causa una disfunción aguda y crónica del cerebro, produciendo trastornos en el sistema nervioso central, presentando alteraciones en la memoria y en las funciones intelectuales como cálculo, comprensión y aprendizaje. A nivel hepático tiene lugar, en su mayoría, el metabolismo del alcohol, produciéndose un hígado graso alcohólico, aumentando el tamaño, terminando en necrosis e inflamación grave del hígado; esto se llama hepatitis alcohólica, y si se sigue consumiendo alcohol se desarrollará la cirrosis. El alcohol también ha estado relacionado con alteraciones del miocardio; se ha constatado en animales de experimentación sanos que tanto la velocidad de contracción del músculo cardiaco y su máxima tensión disminuyen en presencia del alcohol, como consecuencia, la fuerza de cada contracción y el aumento de presión en el ventrículo izquierdo son menores, perdiendo eficacia el corazón como bomba.

  7. Handbook of Markov chain Monte Carlo

    CERN Document Server

    Brooks, Steve

    2011-01-01

    ""Handbook of Markov Chain Monte Carlo"" brings together the major advances that have occurred in recent years while incorporating enough introductory material for new users of MCMC. Along with thorough coverage of the theoretical foundations and algorithmic and computational methodology, this comprehensive handbook includes substantial realistic case studies from a variety of disciplines. These case studies demonstrate the application of MCMC methods and serve as a series of templates for the construction, implementation, and choice of MCMC methodology.

  8. Accelerated Monte Carlo by Embedded Cluster Dynamics

    Science.gov (United States)

    Brower, R. C.; Gross, N. A.; Moriarty, K. J. M.

    1991-07-01

    We present an overview of the new methods for embedding Ising spins in continuous fields to achieve accelerated cluster Monte Carlo algorithms. The methods of Brower and Tamayo and Wolff are summarized and variations are suggested for the O( N) models based on multiple embedded Z2 spin components and/or correlated projections. Topological features are discussed for the XY model and numerical simulations presented for d=2, d=3 and mean field theory lattices.

  9. Inhomogeneous Monte Carlo simulations of dermoscopic spectroscopy

    Science.gov (United States)

    Gareau, Daniel S.; Li, Ting; Jacques, Steven; Krueger, James

    2012-03-01

    Clinical skin-lesion diagnosis uses dermoscopy: 10X epiluminescence microscopy. Skin appearance ranges from black to white with shades of blue, red, gray and orange. Color is an important diagnostic criteria for diseases including melanoma. Melanin and blood content and distribution impact the diffuse spectral remittance (300-1000nm). Skin layers: immersion medium, stratum corneum, spinous epidermis, basal epidermis and dermis as well as laterally asymmetric features (eg. melanocytic invasion) were modeled in an inhomogeneous Monte Carlo model.

  10. An introduction to Monte Carlo methods

    Science.gov (United States)

    Walter, J.-C.; Barkema, G. T.

    2015-01-01

    Monte Carlo simulations are methods for simulating statistical systems. The aim is to generate a representative ensemble of configurations to access thermodynamical quantities without the need to solve the system analytically or to perform an exact enumeration. The main principles of Monte Carlo simulations are ergodicity and detailed balance. The Ising model is a lattice spin system with nearest neighbor interactions that is appropriate to illustrate different examples of Monte Carlo simulations. It displays a second order phase transition between disordered (high temperature) and ordered (low temperature) phases, leading to different strategies of simulations. The Metropolis algorithm and the Glauber dynamics are efficient at high temperature. Close to the critical temperature, where the spins display long range correlations, cluster algorithms are more efficient. We introduce the rejection free (or continuous time) algorithm and describe in details an interesting alternative representation of the Ising model using graphs instead of spins with the so-called Worm algorithm. We conclude with an important discussion of the dynamical effects such as thermalization and correlation time.

  11. Caracterización estructural y propuesta de restauración del bosque nativo de la Comuna El Pital, zona de amortiguamiento del Parque Nacional Machalilla, Ecuador

    OpenAIRE

    Cantos Cevallos, Cristóbal Gonzalo

    2014-01-01

    Con el objetivo de caracterizar la composición y estructura de las formaciones forestales de la Comuna el Pital, Zona de Amortiguamiento del Parque Nacional Machalilla y elaborar pautas de acciones de restauración ecológica para su conservación se llevó a cabo la caracterización estructural de cuatro localidades del bosque seco ecuatorial pertenecientes a dos formaciones vegetales, el monte espinoso tropical y el monte espinoso premontano que van desde 40 a 460 msnm. Para la investigación se ...

  12. Sísmica de reflexión de alta resolución en el estudio del Cuaternario de áreas de pie de monte Shallow, high-resolution seismic reflection in the study of the Quaternary in foothill areas

    Directory of Open Access Journals (Sweden)

    G. González Bonorino

    2003-03-01

    Full Text Available Se realizaron varias pruebas piloto con sísmica de reflexión de baja profundidad en depósitos de abanicos aluviales distales en la provincia de Salta, Argentina. Las pruebas incluyen dos áreas con características de subsuelo contrastantes. En el sector nororiental de la provincia, los depósitos del extenso abanico aluvial del Bermejo son arenosos y macizos, casi sin intercalaciones arcillosas; la napa se encontraba a más de 40 m de profundidad al tiempo del estudio. La otra zona de prueba se ubica al sur de la ciudad de Salta, donde coalescen abanicos aluviales pequeños que rellenan el valle de Lerma con depósitos de arena y grava, los cuales en los tramos distales se interdigitan con potentes capas arcillosas; la napa en esta área se hallaba a una profundidad mayor de 20 m al momento del estudio. La operación sísmica empleó un sismógrafo Geometrics R24 con 24 canales activos que se aumentaron a 48 mediante un "roll-over switch", alcanzando un máximo de cobertura de 1200%. Se probaron dos fuentes de sonido: una masa de 5 kg y una escopeta calibre 12. Principalmente por razones operativas se eligió como fuente la masa. Las pruebas en el abanico del Bermejo dieron registros de baja calidad, probablemente debido a la rápida pérdida de energía en las areas poco consolidadas y secas. Localmente, sin embargo, pudieron distinguirse tres unidades sísmicas y el techo del Terciario posiblemente fue detectado. Las pruebas en eje del valle de Lerma dieron registros sísmicos de excelente calidad. Se distinguieron cuatro unidades sísmicas. Un reflector débil a aproximadamente 220 mseg coincide con un cambio de las velocidades a unos 2500 m/seg y puede corresponder con el techo del sustrato terciario. Una potente capa de arcilla a una profundidad de 25 a 50 m puede claramente mapearse como un acuitardo. Los resultados de este estudio piloto demuestran que la sísmica de reflexión de poca profundidad puede ser aplicada con provecho en el

  13. Aplicación del Método de Monte Carlo a la Planificación en Radioterapia y a la Reconstrucción de Espectros de Fotones de Aceleradores Lineales de Partículas (LinAc)

    OpenAIRE

    Juste Vidal, Belen Jeanine

    2011-01-01

    La radioterapia es uno de los tratamientos más generalizados aplicados a los pacientes que padecen determinados tipos de cáncer. Sin embargo, la efectividad de este tipo de tratamientos en la destrucción de las células cancerígenas lleva asociada la posibilidad de sufrir los efectos secundarios de la radiación sobre los tejidos sanos circundantes. El riesgo de lesión de las células sanas depende fundamentalmente de la orientación del haz emitido por la unidad de radioterapia y de la intensida...

  14. Belo Monte hydropower project: actual studies; AHE Belo Monte: os estudos atuais

    Energy Technology Data Exchange (ETDEWEB)

    Figueira Netto, Carlos Alberto de Moya [CNEC Engenharia S.A., Sao Paulo, SP (Brazil); Rezende, Paulo Fernando Vieira Souto [Centrais Eletricas Brasileiras S.A. (ELETROBRAS), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    This article presents the evolution of the studies of Belo Monte Hydro Power Project (HPP) since the initial inventory studies of the Xingu River in 1979 until the current studies for conclusion of the Technical, Economic and Environmental Feasibility Studies the Belo Monte Hydro Power Project, as authorized by Brazilian National Congress. The current studies characterize the Belo Monte HPP with an installed capacity of 11,181.3 MW (20 units of 550 MW in the main power house and 7 units of 25.9 MW in the additional power house), connected to the Brazilian Interconnected Power Grid, allowing to generate 4,796 mean MW of firm energy, without depending on any flow rate regularization of the upstream Xingu river flooding only 441 k m2, of which approximately 200 k m2, correspond to the normal annual wet season flooding of the Xingu River. (author)

  15. Guideline of Monte Carlo calculation. Neutron/gamma ray transport simulation by Monte Carlo method

    CERN Document Server

    2002-01-01

    This report condenses basic theories and advanced applications of neutron/gamma ray transport calculations in many fields of nuclear energy research. Chapters 1 through 5 treat historical progress of Monte Carlo methods, general issues of variance reduction technique, cross section libraries used in continuous energy Monte Carlo codes. In chapter 6, the following issues are discussed: fusion benchmark experiments, design of ITER, experiment analyses of fast critical assembly, core analyses of JMTR, simulation of pulsed neutron experiment, core analyses of HTTR, duct streaming calculations, bulk shielding calculations, neutron/gamma ray transport calculations of the Hiroshima atomic bomb. Chapters 8 and 9 treat function enhancements of MCNP and MVP codes, and a parallel processing of Monte Carlo calculation, respectively. An important references are attached at the end of this report.

  16. Culturas del Mundo

    DEFF Research Database (Denmark)

    Benwell, Ann Fenger; Costa, Alberto; Waehle, Espen

    2006-01-01

    ’Culturas del mundo. Colecciones del Museo Nacional de Dinamarca’ with Ann Fenger Benwell in Culturas del Mundo. Colecciones del Museo Nacional de Dinamarca, ed. Silvia Sauquet, Fundación "la Caixa", Barcelona 2006, pp. 31-39......’Culturas del mundo. Colecciones del Museo Nacional de Dinamarca’ with Ann Fenger Benwell in Culturas del Mundo. Colecciones del Museo Nacional de Dinamarca, ed. Silvia Sauquet, Fundación "la Caixa", Barcelona 2006, pp. 31-39...

  17. Efecto de la severidad de quemado sobre la concentración de carbono orgánico en montículos e intermontículos en el monte austral Effect of burn severity on the soil organic carbon concentration mounds and intermounds in the monte austral

    Directory of Open Access Journals (Sweden)

    Juan José Gaitán

    2007-12-01

    Full Text Available El efecto de la severidad de quemado sobre la concentración de carbono orgánico (COS en los montículos vegetados y en los intermontículos de suelo desnudo fue evaluado 4 años luego de la ocurrencia de un incendio natural en un área del Monte Austral (provincia de Río Negro. Los montículos actúan como "islas de fertilidad" dado que la concentración de COS fue mayor que en los intermontículos. La concentración de COS en los intermontículos no fue afectada por el incendio. En cambio en los montículos se halló una disminución en la concentración de COS al incrementarse la severidad de quemado. La pérdida de COS podría inducir una degradación de los pastizales, por lo tanto las prácticas de manejo del fuego deberían tender a la realización de quemas de baja severidad.The effect of burn severity on soil organic carbon concentration (COS in vegetated mounds and in bare soil intermounds was evaluated 4 years after the occurrence of a natural fire in an area of the Monte Austral (Río Negro province. The mounds act as "fertility islands" since COS concentration was higher than in the intermounds. The COS concentration in the intermounds was not affected by fire. On the other hand, in the mounds a decrease in the COS concentration was found when the burn severity increased. The COS loss could induce rangelands degradation, therefore fire management practices should tend to the realization of low severity burns.

  18. Monte Carlo calculations on the magnetization profile and domain wall structure in bulk systems and nanoconstricitons

    Energy Technology Data Exchange (ETDEWEB)

    Serena, P. A. [Instituto de Ciencias de Materiales de Madrid, Madrid (Spain); Costa-Kraemer, J. L. [Instituto de Microelectronica de Madrid, Madrid (Spain)

    2001-03-01

    A Monte Carlo algorithm suitable to study systems described by an anisotropic Heisenberg Hamiltonian is presented. This technique has been tested successfully with 3D and 2D systems, illustrating how magnetic properties depend on the dimensionality and the coordination number. We have found that magnetic properties of constrictions differ from those appearing in bulk. In particular, spin fluctuations are considerable larger than those calculated for bulk materials. In addition, domain walls are strongly modified when a constriction is present, with a decrease of the domain-wall width. This decrease is explained in terms of previous theoretical works. [Spanish] Se presenta un algoritmo de Monte Carlo para estudiar sistemas discritos por un hamiltoniano anisotropico de Heisenburg. Esta tecnica ha sido probada exitosamente con sistemas de dos y tres dimensiones, ilustrado con las propiedades magneticas dependen de la dimensionalidad y el numero de coordinacion. Hemos encontrado que las propiedades magneticas de constricciones difieren de aquellas del bulto. En particular, las fluctuaciones de espin son considerablemente mayores. Ademas, las paredes de dominio son fuertemente modificadas cuando una construccion esta presente, originando un decrecimiento del ancho de la pared de dominio. Damos cuenta de este decrecimiento en terminos de un trabajo teorico previo.

  19. Espesura crítica y regeneración en un pinar natural de silvestre de elevada complejidad estructural (monte “Cabeza de Hierro”, Rascafría, Madrid)

    OpenAIRE

    Rubio Cuadrado, Álvaro; Vivar Sanz, Alejandro; Sadornil Arenas, Enrique; Aroca Fernández, Mª José; Serrada Hierro, Rafael; Bravo Fernandez, Jose Alfredo

    2009-01-01

    El monte privado “Cabeza de Hierro” (Rascafría, Madrid), con 2.016,5 ha de superficie total y 1.886,4 ha de superficie arbolada, presenta una masa de pino silvestre de origen natural con abundante melojo, de elevado valor económico y ecológico, sobre la que se realizan aprovechamientos maderables desde hace al menos 150 años. La mayor parte del monte está incluido en la Zona Periférica de Protección del Parque Natural de la Cumbre, Circo y Lagunas de Peñalara. Ordenado desde 1957, se si...

  20. Status of Monte-Carlo Event Generators

    Energy Technology Data Exchange (ETDEWEB)

    Hoeche, Stefan; /SLAC

    2011-08-11

    Recent progress on general-purpose Monte-Carlo event generators is reviewed with emphasis on the simulation of hard QCD processes and subsequent parton cascades. Describing full final states of high-energy particle collisions in contemporary experiments is an intricate task. Hundreds of particles are typically produced, and the reactions involve both large and small momentum transfer. The high-dimensional phase space makes an exact solution of the problem impossible. Instead, one typically resorts to regarding events as factorized into different steps, ordered descending in the mass scales or invariant momentum transfers which are involved. In this picture, a hard interaction, described through fixed-order perturbation theory, is followed by multiple Bremsstrahlung emissions off initial- and final-state and, finally, by the hadronization process, which binds QCD partons into color-neutral hadrons. Each of these steps can be treated independently, which is the basic concept inherent to general-purpose event generators. Their development is nowadays often focused on an improved description of radiative corrections to hard processes through perturbative QCD. In this context, the concept of jets is introduced, which allows to relate sprays of hadronic particles in detectors to the partons in perturbation theory. In this talk, we briefly review recent progress on perturbative QCD in event generation. The main focus lies on the general-purpose Monte-Carlo programs HERWIG, PYTHIA and SHERPA, which will be the workhorses for LHC phenomenology. A detailed description of the physics models included in these generators can be found in [8]. We also discuss matrix-element generators, which provide the parton-level input for general-purpose Monte Carlo.

  1. Venus - Maxwell Montes and Cleopatra Crater

    Science.gov (United States)

    1991-01-01

    This Magellan full-resolution image shows Maxwell Montes, and is centered at 65 degrees north latitude and 6 degrees east longitude. Maxwell is the highest mountain on Venus, rising almost 11 kilometers (6.8 miles) above mean planetary radius. The western slopes (on the left) are very steep, whereas the eastern slopes descend gradually into Fortuna Tessera. The broad ridges and valleys making up Maxwell and Fortuna suggest that the topography resulted from compression. Most of Maxwell Montes has a very bright radar return; such bright returns are common on Venus at high altitudes. This phenomenon is thought to result from the presence of a radar reflective mineral such as pyrite. Interestingly, the highest area on Maxwell is less bright than the surrounding slopes, suggesting that the phenomenon is limited to a particular elevation range. The pressure, temperature, and chemistry of the atmosphere vary with altitude; the material responsible for the bright return probably is only stable in a particular range of atmospheric conditions and therefore a particular elevation range. The prominent circular feature in eastern Maxwell is Cleopatra. Cleopatra is a double-ring impact basin about 100 kilometers (62 miles) in diameter and 2.5 kilometers (1.5 miles) deep. A steep-walled, winding channel a few kilometers wide breaks through the rough terrain surrounding the crater rim. A large amount of lava originating in Cleopatra flowed through this channel and filled valleys in Fortuna Tessera. Cleopatra is superimposed on the structures of Maxwell Montes and appears to be undeformed, indicating that Cleopatra is relatively young.

  2. Livestock grazing, habitat protection and diversity of bees and wasps in the Central Monte desert

    Directory of Open Access Journals (Sweden)

    Diego P. VÁZQUEZ

    2008-01-01

    Full Text Available El principal objetivo de las reservas es prevenir o mitigar los impactos humanos sobre los ecosistemas naturales. Es importante evaluar cuán bien las reservas alcanzan este objetivo. Evaluamos si la protección del hábitat que brinda la Reserva de la Biósfera de Ñacuñán (Monte Central, Argentina resulta en cambios detectables en la estructura del hábitat, y en la riqueza y la composición de especies de abejas y avispas. Realizamos muestreos con trampas bandeja y observaciones de visitantes florales en seis pares de sitios dentro y fuera de la reserva. Nuestros resultados sugieren que los treinta y cinco años de exclusión del ganado vacuno en Ñacuñán han tenido efectos detectables sobre la estructura del hábitat. Sin embargo, estos cambios en el hábitat se tradujeron sólo en efectos parciales y conflictivos sobre la riqueza de himenópteros, y no tuvieron efectos detectables sobre la composición de himenópteros. Nuestro estudio debería repetirse en el futuro, con un mayor esfuerzo de muestreo y a lo largo de varios años antes que estos resultados puedan ser aplicados como guía de decisiones de manejo.

  3. Mosaic crystal algorithm for Monte Carlo simulations

    CERN Document Server

    Seeger, P A

    2002-01-01

    An algorithm is presented for calculating reflectivity, absorption, and scattering of mosaic crystals in Monte Carlo simulations of neutron instruments. The algorithm uses multi-step transport through the crystal with an exact solution of the Darwin equations at each step. It relies on the kinematical model for Bragg reflection (with parameters adjusted to reproduce experimental data). For computation of thermal effects (the Debye-Waller factor and coherent inelastic scattering), an expansion of the Debye integral as a rapidly converging series of exponential terms is also presented. Any crystal geometry and plane orientation may be treated. The algorithm has been incorporated into the neutron instrument simulation package NISP. (orig.)

  4. Monte Carlo simulation for the transport beamline

    Energy Technology Data Exchange (ETDEWEB)

    Romano, F.; Cuttone, G.; Jia, S. B.; Varisano, A. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Attili, A.; Marchetto, F.; Russo, G. [INFN, Sezione di Torino, Via P.Giuria, 1 10125 Torino (Italy); Cirrone, G. A. P.; Schillaci, F.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Institute of Physics Czech Academy of Science, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Carpinelli, M. [INFN Sezione di Cagliari, c/o Dipartimento di Fisica, Università di Cagliari, Cagliari (Italy); Tramontana, A. [INFN, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania, Italy and Università di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy)

    2013-07-26

    In the framework of the ELIMED project, Monte Carlo (MC) simulations are widely used to study the physical transport of charged particles generated by laser-target interactions and to preliminarily evaluate fluence and dose distributions. An energy selection system and the experimental setup for the TARANIS laser facility in Belfast (UK) have been already simulated with the GEANT4 (GEometry ANd Tracking) MC toolkit. Preliminary results are reported here. Future developments are planned to implement a MC based 3D treatment planning in order to optimize shots number and dose delivery.

  5. A note on simultaneous Monte Carlo tests

    DEFF Research Database (Denmark)

    Hahn, Ute

    In this short note, Monte Carlo tests of goodness of fit for data of the form X(t), t ∈ I are considered, that reject the null hypothesis if X(t) leaves an acceptance region bounded by an upper and lower curve for some t in I. A construction of the acceptance region is proposed that complies to a...... to a given target level of rejection, and yields exact p-values. The construction is based on pointwise quantiles, estimated from simulated realizations of X(t) under the null hypothesis....

  6. A Monte Carlo algorithm for degenerate plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Turrell, A.E., E-mail: a.turrell09@imperial.ac.uk; Sherlock, M.; Rose, S.J.

    2013-09-15

    A procedure for performing Monte Carlo calculations of plasmas with an arbitrary level of degeneracy is outlined. It has possible applications in inertial confinement fusion and astrophysics. Degenerate particles are initialised according to the Fermi–Dirac distribution function, and scattering is via a Pauli blocked binary collision approximation. The algorithm is tested against degenerate electron–ion equilibration, and the degenerate resistivity transport coefficient from unmagnetised first order transport theory. The code is applied to the cold fuel shell and alpha particle equilibration problem of inertial confinement fusion.

  7. Archimedes, the Free Monte Carlo simulator

    CERN Document Server

    Sellier, Jean Michel D

    2012-01-01

    Archimedes is the GNU package for Monte Carlo simulations of electron transport in semiconductor devices. The first release appeared in 2004 and since then it has been improved with many new features like quantum corrections, magnetic fields, new materials, GUI, etc. This document represents the first attempt to have a complete manual. Many of the Physics models implemented are described and a detailed description is presented to make the user able to write his/her own input deck. Please, feel free to contact the author if you want to contribute to the project.

  8. Cluster hybrid Monte Carlo simulation algorithms

    Science.gov (United States)

    Plascak, J. A.; Ferrenberg, Alan M.; Landau, D. P.

    2002-06-01

    We show that addition of Metropolis single spin flips to the Wolff cluster-flipping Monte Carlo procedure leads to a dramatic increase in performance for the spin-1/2 Ising model. We also show that adding Wolff cluster flipping to the Metropolis or heat bath algorithms in systems where just cluster flipping is not immediately obvious (such as the spin-3/2 Ising model) can substantially reduce the statistical errors of the simulations. A further advantage of these methods is that systematic errors introduced by the use of imperfect random-number generation may be largely healed by hybridizing single spin flips with cluster flipping.

  9. Introduction to Cluster Monte Carlo Algorithms

    Science.gov (United States)

    Luijten, E.

    This chapter provides an introduction to cluster Monte Carlo algorithms for classical statistical-mechanical systems. A brief review of the conventional Metropolis algorithm is given, followed by a detailed discussion of the lattice cluster algorithm developed by Swendsen and Wang and the single-cluster variant introduced by Wolff. For continuum systems, the geometric cluster algorithm of Dress and Krauth is described. It is shown how their geometric approach can be generalized to incorporate particle interactions beyond hardcore repulsions, thus forging a connection between the lattice and continuum approaches. Several illustrative examples are discussed.

  10. Exascale Monte Carlo R&D

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, Ryan C. [Los Alamos National Laboratory

    2012-07-24

    Overview of this presentation is (1) Exascale computing - different technologies, getting there; (2) high-performance proof-of-concept MCMini - features and results; and (3) OpenCL toolkit - Oatmeal (OpenCL Automatic Memory Allocation Library) - purpose and features. Despite driver issues, OpenCL seems like a good, hardware agnostic tool. MCMini demonstrates the possibility for GPGPU-based Monte Carlo methods - it shows great scaling for HPC application and algorithmic equivalence. Oatmeal provides a flexible framework to aid in the development of scientific OpenCL codes.

  11. State-of-the-art Monte Carlo 1988

    Energy Technology Data Exchange (ETDEWEB)

    Soran, P.D.

    1988-06-28

    Particle transport calculations in highly dimensional and physically complex geometries, such as detector calibration, radiation shielding, space reactors, and oil-well logging, generally require Monte Carlo transport techniques. Monte Carlo particle transport can be performed on a variety of computers ranging from APOLLOs to VAXs. Some of the hardware and software developments, which now permit Monte Carlo methods to be routinely used, are reviewed in this paper. The development of inexpensive, large, fast computer memory, coupled with fast central processing units, permits Monte Carlo calculations to be performed on workstations, minicomputers, and supercomputers. The Monte Carlo renaissance is further aided by innovations in computer architecture and software development. Advances in vectorization and parallelization architecture have resulted in the development of new algorithms which have greatly reduced processing times. Finally, the renewed interest in Monte Carlo has spawned new variance reduction techniques which are being implemented in large computer codes. 45 refs.

  12. Discrete diffusion Monte Carlo for frequency-dependent radiative transfer

    Energy Technology Data Exchange (ETDEWEB)

    Densmore, Jeffrey D [Los Alamos National Laboratory; Kelly, Thompson G [Los Alamos National Laboratory; Urbatish, Todd J [Los Alamos National Laboratory

    2010-11-17

    Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Implicit Monte Carlo radiative-transfer simulations. In this paper, we develop an extension of DDMC for frequency-dependent radiative transfer. We base our new DDMC method on a frequency-integrated diffusion equation for frequencies below a specified threshold. Above this threshold we employ standard Monte Carlo. With a frequency-dependent test problem, we confirm the increased efficiency of our new DDMC technique.

  13. Alternative Monte Carlo Approach for General Global Illumination

    Institute of Scientific and Technical Information of China (English)

    徐庆; 李朋; 徐源; 孙济洲

    2004-01-01

    An alternative Monte Carlo strategy for the computation of global illumination problem was presented.The proposed approach provided a new and optimal way for solving Monte Carlo global illumination based on the zero variance importance sampling procedure. A new importance driven Monte Carlo global illumination algorithm in the framework of the new computing scheme was developed and implemented. Results, which were obtained by rendering test scenes, show that this new framework and the newly derived algorithm are effective and promising.

  14. Avaliação do uso de medicamentos pela população idosa em Montes Claros, Minas Gerais, Brasil Evaluación del uso de los medicamentos por la población anciana Evaluation of medication use among elderly population

    Directory of Open Access Journals (Sweden)

    Carla Silvana Oliveira Silva

    2010-12-01

    Full Text Available Inserido no universo do cuidado de enfermagem à pessoa idosa, o estudo descreve o perfil sociodemográfico e verifica o uso de medicação segundo gênero em idosos cadastrados em um PSF. MÉTODO: Estudo quantitativo, descritivo, transversal com pesquisa de campo. Utilizou-se o questionário semiestruturado, possibilitando identificar o perfil desses usuários, as principais morbidades, os medicamentos utilizados e as dificuldades relatadas por eles quanto ao uso dos medicamentos. O universo foi de 211 idosos. Na análise dos dados utilizou-se o programa SPSS, priorizando a associação estatística de forma analítica. RESULTADOS: Entre os idosos em uso de medicamentos, verificou-se predominância feminina, renda familiar e escolaridade baixas, idosos vivendo com familiares e sem dificuldades no uso de medicamentos. Uso de medicamentos foi comum em mais de 90% dos idosos. Verificou-se associação para "ausência de dificuldades no uso do medicamento" e "orientações do PSF" (PInserido en el universo del cuidado de enfermería al anciano, el estudio describe el perfil sociodemográfico y verifica el uso de medicación según género en acianos asistidos en una unidad del Programa de Salud Familiar. MÉTODO: Estudio cuantitativo, descriptivo y transversal con trabajo de campo. Fue utilizado cuestionario seme-estructurado, posibilitando identificar el perfil de los usuarios, las principales morbilidades, los medicamentos utilizados y las dificultades relatadas por ellos en relación al uso de los medicamentos. En el análisis de los dados, fue utilizado el programa SPSS, priorizando la asociación estadística de forma analítica. RESULTADOS: Entre los ancianos con uso de medicamentos, fue verificado predominancia femenina, renda familiar y escolaridad bajas, ancianos viviendo con los familiares y sin dificultades en uso de los medicamentos. El uso de medicamento fue común en más de 90% de los ancianos. Fue verificado asociación para

  15. Multiple Monte Carlo Testing with Applications in Spatial Point Processes

    DEFF Research Database (Denmark)

    Mrkvička, Tomáš; Myllymäki, Mari; Hahn, Ute

    with a function as the test statistic, 3) several Monte Carlo tests with functions as test statistics. The rank test has correct (global) type I error in each case and it is accompanied with a p-value and with a graphical interpretation which shows which subtest or which distances of the used test function......The rank envelope test (Myllym\\"aki et al., Global envelope tests for spatial processes, arXiv:1307.0239 [stat.ME]) is proposed as a solution to multiple testing problem for Monte Carlo tests. Three different situations are recognized: 1) a few univariate Monte Carlo tests, 2) a Monte Carlo test...

  16. Discrete range clustering using Monte Carlo methods

    Science.gov (United States)

    Chatterji, G. B.; Sridhar, B.

    1993-01-01

    For automatic obstacle avoidance guidance during rotorcraft low altitude flight, a reliable model of the nearby environment is needed. Such a model may be constructed by applying surface fitting techniques to the dense range map obtained by active sensing using radars. However, for covertness, passive sensing techniques using electro-optic sensors are desirable. As opposed to the dense range map obtained via active sensing, passive sensing algorithms produce reliable range at sparse locations, and therefore, surface fitting techniques to fill the gaps in the range measurement are not directly applicable. Both for automatic guidance and as a display for aiding the pilot, these discrete ranges need to be grouped into sets which correspond to objects in the nearby environment. The focus of this paper is on using Monte Carlo methods for clustering range points into meaningful groups. One of the aims of the paper is to explore whether simulated annealing methods offer significant advantage over the basic Monte Carlo method for this class of problems. We compare three different approaches and present application results of these algorithms to a laboratory image sequence and a helicopter flight sequence.

  17. Information Geometry and Sequential Monte Carlo

    CERN Document Server

    Sim, Aaron; Stumpf, Michael P H

    2012-01-01

    This paper explores the application of methods from information geometry to the sequential Monte Carlo (SMC) sampler. In particular the Riemannian manifold Metropolis-adjusted Langevin algorithm (mMALA) is adapted for the transition kernels in SMC. Similar to its function in Markov chain Monte Carlo methods, the mMALA is a fully adaptable kernel which allows for efficient sampling of high-dimensional and highly correlated parameter spaces. We set up the theoretical framework for its use in SMC with a focus on the application to the problem of sequential Bayesian inference for dynamical systems as modelled by sets of ordinary differential equations. In addition, we argue that defining the sequence of distributions on geodesics optimises the effective sample sizes in the SMC run. We illustrate the application of the methodology by inferring the parameters of simulated Lotka-Volterra and Fitzhugh-Nagumo models. In particular we demonstrate that compared to employing a standard adaptive random walk kernel, the SM...

  18. Quantum Monte Carlo Calculations of Neutron Matter

    CERN Document Server

    Carlson, J; Ravenhall, D G

    2003-01-01

    Uniform neutron matter is approximated by a cubic box containing a finite number of neutrons, with periodic boundary conditions. We report variational and Green's function Monte Carlo calculations of the ground state of fourteen neutrons in a periodic box using the Argonne $\\vep $ two-nucleon interaction at densities up to one and half times the nuclear matter density. The effects of the finite box size are estimated using variational wave functions together with cluster expansion and chain summation techniques. They are small at subnuclear densities. We discuss the expansion of the energy of low-density neutron gas in powers of its Fermi momentum. This expansion is strongly modified by the large nn scattering length, and does not begin with the Fermi-gas kinetic energy as assumed in both Skyrme and relativistic mean field theories. The leading term of neutron gas energy is ~ half the Fermi-gas kinetic energy. The quantum Monte Carlo results are also used to calibrate the accuracy of variational calculations ...

  19. THE MCNPX MONTE CARLO RADIATION TRANSPORT CODE

    Energy Technology Data Exchange (ETDEWEB)

    WATERS, LAURIE S. [Los Alamos National Laboratory; MCKINNEY, GREGG W. [Los Alamos National Laboratory; DURKEE, JOE W. [Los Alamos National Laboratory; FENSIN, MICHAEL L. [Los Alamos National Laboratory; JAMES, MICHAEL R. [Los Alamos National Laboratory; JOHNS, RUSSELL C. [Los Alamos National Laboratory; PELOWITZ, DENISE B. [Los Alamos National Laboratory

    2007-01-10

    MCNPX (Monte Carlo N-Particle eXtended) is a general-purpose Monte Carlo radiation transport code with three-dimensional geometry and continuous-energy transport of 34 particles and light ions. It contains flexible source and tally options, interactive graphics, and support for both sequential and multi-processing computer platforms. MCNPX is based on MCNP4B, and has been upgraded to most MCNP5 capabilities. MCNP is a highly stable code tracking neutrons, photons and electrons, and using evaluated nuclear data libraries for low-energy interaction probabilities. MCNPX has extended this base to a comprehensive set of particles and light ions, with heavy ion transport in development. Models have been included to calculate interaction probabilities when libraries are not available. Recent additions focus on the time evolution of residual nuclei decay, allowing calculation of transmutation and delayed particle emission. MCNPX is now a code of great dynamic range, and the excellent neutronics capabilities allow new opportunities to simulate devices of interest to experimental particle physics; particularly calorimetry. This paper describes the capabilities of the current MCNPX version 2.6.C, and also discusses ongoing code development.

  20. Chemical application of diffusion quantum Monte Carlo

    Science.gov (United States)

    Reynolds, P. J.; Lester, W. A., Jr.

    1983-10-01

    The diffusion quantum Monte Carlo (QMC) method gives a stochastic solution to the Schroedinger equation. As an example the singlet-triplet splitting of the energy of the methylene molecule CH2 is given. The QMC algorithm was implemented on the CYBER 205, first as a direct transcription of the algorithm running on our VAX 11/780, and second by explicitly writing vector code for all loops longer than a crossover length C. The speed of the codes relative to one another as a function of C, and relative to the VAX is discussed. Since CH2 has only eight electrons, most of the loops in this application are fairly short. The longest inner loops run over the set of atomic basis functions. The CPU time dependence obtained versus the number of basis functions is discussed and compared with that obtained from traditional quantum chemistry codes and that obtained from traditional computer architectures. Finally, preliminary work on restructuring the algorithm to compute the separate Monte Carlo realizations in parallel is discussed.

  1. Landscape changes and human activity in Monte Penide (Redondela, Pontevedra: a methodological approach

    Directory of Open Access Journals (Sweden)

    Martínez Cortizas, Antonio

    2000-06-01

    Full Text Available We have surveyed two areas with open air rock art in Monte Penide, finding in the process several artefact scatters near the petro glyphs of roughly the same age. Also, we have undertaken a soil analysis of a section already exposed in one of those places (Coto da Fenteira, looking for occurrences of enrichment in certain trace elements (Ti, Zr, Hg or Br along the sequence. As a result of this studies in combination with 14C dating of charcoal and organic matter, we have been able to define two main erosive episodes, resulting from human activity: one in the first half of the third millennium BC and a second, less violent one, from the start of the second millennium BC. These episodes have to do mostly with the spread of a farming economy during the Chalcolithic and its consolidation along the Earlier Bronze Age, thus rejecting the notion of a socioeconomic crisis during the latter and showing, instead, a progressive interference with the environment by human groups up to the second Iron Age.

    Hemos prospectado dos áreas con manifestaciones de arte rupestre en Monte Penide, descubriendo en su cercanía concentraciones de material cerámico y lítico de cronología semejante. Uno de los lugares examinados (Coto da Fenteira fue objeto de un análisis edafológico sobre un corte abierto por obras recientes. La combinación de estudios sobre elementos traza (Ti, Zr, Hg o Br y de dataciones C-14 ha permitido definir un suelo policíclico que se extiende a lo largo del Holoceno y en el que se diferencian dos grandes episodios erosivos vinculados a la acción antrópica: uno a partir de la primera mitad del III milenio AC y otro menos violento desde inicios del II milenio, coincidentes grosso modo con la expansión del sistema agropastoril durante el Calcolítico y su continuación a lo largo del Bronce inicial/medio regional, desmintiendo así la noción de una crisis socioeconómica durante el segundo período y apoyando, en cambio, la

  2. Quantum Monte Carlo Endstation for Petascale Computing

    Energy Technology Data Exchange (ETDEWEB)

    Lubos Mitas

    2011-01-26

    NCSU research group has been focused on accomplising the key goals of this initiative: establishing new generation of quantum Monte Carlo (QMC) computational tools as a part of Endstation petaflop initiative for use at the DOE ORNL computational facilities and for use by computational electronic structure community at large; carrying out high accuracy quantum Monte Carlo demonstration projects in application of these tools to the forefront electronic structure problems in molecular and solid systems; expanding the impact of QMC methods and approaches; explaining and enhancing the impact of these advanced computational approaches. In particular, we have developed quantum Monte Carlo code (QWalk, www.qwalk.org) which was significantly expanded and optimized using funds from this support and at present became an actively used tool in the petascale regime by ORNL researchers and beyond. These developments have been built upon efforts undertaken by the PI's group and collaborators over the period of the last decade. The code was optimized and tested extensively on a number of parallel architectures including petaflop ORNL Jaguar machine. We have developed and redesigned a number of code modules such as evaluation of wave functions and orbitals, calculations of pfaffians and introduction of backflow coordinates together with overall organization of the code and random walker distribution over multicore architectures. We have addressed several bottlenecks such as load balancing and verified efficiency and accuracy of the calculations with the other groups of the Endstation team. The QWalk package contains about 50,000 lines of high quality object-oriented C++ and includes also interfaces to data files from other conventional electronic structure codes such as Gamess, Gaussian, Crystal and others. This grant supported PI for one month during summers, a full-time postdoc and partially three graduate students over the period of the grant duration, it has resulted in 13

  3. Nuovi reperti dal villaggio pre-protostorico di Monte Olladiri in Monastir (CA: la cultura di Ozieri

    Directory of Open Access Journals (Sweden)

    Barbara Costa

    2012-06-01

    Full Text Available Questo lavoro consiste nello studio di manufatti ceramici raccolti in prospezioni di superficie dal Prof. Giovanni Ugas nel sito archeologico di Monte Olladiri, nel territorio del comune di Monastir (CA. Lo studio riguarda reperti pertinenti alla cultura di Ozieri e Sub-Ozieri provenienti dal lotto Coccodi (F23, Mp. 46A ed é la sintesi della tesi di specializzazione in Archeologia della scrivente, presentata nell’Aprile 2008 presso l’Universita’ di Cagliari. Obiettivo primario è il loro inquadramento all’interno della facies archeologica di pertinenza, e i dati scaturiti dall’analisi e dai confronti, saranno utilizzati al fine di ricostruire gli elementi essenziali della comunità che operava a Monte Olladiri. This paper concerns the study of some pottery fragments collected by a surface prospecting made by Prof.Giovanni Ugas in the archaeological site of Monte Olladiri, near a village called Monastir (CA. The study is focused on some findings belonging to the cultures of Ozieri and Sub-Ozieri and coming from the Coccodi lot (F23, Mp. 46A. It is the synthesis of the post lauream specialization school, presented by the writer in April 2008. The main aim is the classification of the materials into the “facies” of archaeological relevance, and the data result from the analysis and comparisons will be used to reconstruct the essential elements of the people who worked at Monte Olladiri.

  4. A new species of Nebria Latreille, 1802 from the Montes de León, north-west Spain (Coleoptera, Carabidae, Nebriinae

    Directory of Open Access Journals (Sweden)

    Zaballos, J. P.

    2000-12-01

    Full Text Available Nebria leonensis sp. n. from the Sierras de la Cabrera Baja and del Teleno (southern Montes de León is described. This species, related to N. lafresnayei Serville, 1821, is characterised by its slender body, long and light brown extremities, the form of its pronotum, and evenly rounded elytra, which are conspicuously flattened on the discus. The differentiating characters and the habitat are described. A determination key to the species and subspecies of the group to which the new species belongs is presented.Se describe Nebria leonensis sp. n. de las sierras de la Cabrera Baja y del Teleno (sur de los Montes de León. Esta especie, relacionada con Nebria lafresnayei Serville, 1821, se caracteriza especialmente por su cuerpo delgado, largas extremidades de color marrón claro, forma del pronoto, y élitros uniformemente redondeados y claramente deprimidos en el disco. Además de describir los caracteres que la definen y el hábitat, se presentan unas breves notas sobre la historia faunística de los montes de León, y una clave de determinación de las especies y subespecies del grupo al que pertenece la nueva especie.

  5. Conocimiento de seis especies arbustivas utilizadas como plantas nodrizas en el occidente de Guatemala

    Directory of Open Access Journals (Sweden)

    José Vicente Martínez-Arévalo

    2015-11-01

    Full Text Available En la restauración de ecosistemas, una técnica es utilizar arbustos de la sucesión como nodriza. En la parte alta de San Marcos, Guatemala, se ha recurrido al menos a seis de ellos en el establecimiento de pino y pinabete: arrayán (Baccharis vaccinoides Kunth, salvia (Buddleia megalocephala Donn. Sm., mozote (Acaena elongata L., chicajol (Stevia polycephala Bertol, mora (Rubus trilobus Ser. y malacate (Symphoricarpos microphyllus Kunth. Se carece de la documentación de su comportamiento y características que puedan servir para utilizarlas ampliamente como plantas protectoras. En esta investigación se estudió características in situ y reproductivas de estas especies. Entre los principales resultados está que la altura de plantas es de 1.17 a 2.64 m y cobertura de 0.34 a 2.77 m2, con una amplia variación entre y dentro de especies. La cantidad de frutos/planta va desde 90 en S. microphyllus a 59,400 en B. vaccinioides. La propagación vegetativa en campo estuvo entre 48 a 92 %, mayor que cuando se realizó en vivero, donde B. vaccinoides, S. microphyllus y R. trilobus tuvieron mejor respuesta. La propagación por semilla muestra que las seis especies pueden reproducirse adecuadamente. Estos resultados permiten su reproducción en viveros para su uso en restauración ecológica.

  6. del Norte

    Directory of Open Access Journals (Sweden)

    Heydi Robles

    2005-01-01

    Full Text Available Este artículo muestra los resultados de una investigación sobre la ansiedad causada por el aprendizaje de idiomas. Está centrado en la ansiedad relacionada con la habilidad de producción oral. El objetivo del estudio era identificar los factores externos que producen ansiedad en el desarrollo de la competencia oral en un grupo de estudiantes de Psicología. Para lograr su objetivo, la investigación utilizó diarios, cuestionarios, grabaciones (opiniones personales, presentaciones orales breves y entrevistas. Con respecto de los factores externos que producen ansiedad en relación con las actividades, los resultados muestran que todas las actividades orales producen un alto grado de ansiedades en los estudiantes, especialmente las actividades no programadas. También muestran una falta de participación en clase con un fuerte rechazo a las actividades orales. Entre las posibles causas de reticencia puede estar el hecho de que los estudiantes no quieren ser objeto de burla. Además, la habilidad de producción oral no fue estimulada en los niveles anteriores del programa de inglés. Es vital mencionar que los alumnos son conscientes de sus carencias en algunos aspectos del idioma como vocabulario, gramática y fluidez.

  7. Monte Carlo模拟薄膜生长的研究%Study of Thin Film Growth by Monte Carlo Stimulation

    Institute of Scientific and Technical Information of China (English)

    彭冬生; 冯玉春; 牛憨笨

    2006-01-01

    阐述了Monte Carlo方法在薄膜生长中的应用和最新进展;简要论述了Monte Carlo算法的类型及各自的特点;结合MonteCarlo方法的特点,提出了模拟薄膜生长的模型以及处理方法.同时,归纳出MonteCarlo模拟薄膜生长需要解决的主要问题.

  8. Reporting Monte Carlo Studies in Structural Equation Modeling

    NARCIS (Netherlands)

    Boomsma, Anne

    2013-01-01

    In structural equation modeling, Monte Carlo simulations have been used increasingly over the last two decades, as an inventory from the journal Structural Equation Modeling illustrates. Reaching out to a broad audience, this article provides guidelines for reporting Monte Carlo studies in that fiel

  9. Quantum Monte Carlo Simulations : Algorithms, Limitations and Applications

    NARCIS (Netherlands)

    Raedt, H. De

    1992-01-01

    A survey is given of Quantum Monte Carlo methods currently used to simulate quantum lattice models. The formalisms employed to construct the simulation algorithms are sketched. The origin of fundamental (minus sign) problems which limit the applicability of the Quantum Monte Carlo approach is shown

  10. Quantum Monte Carlo using a Stochastic Poisson Solver

    Energy Technology Data Exchange (ETDEWEB)

    Das, D; Martin, R M; Kalos, M H

    2005-05-06

    Quantum Monte Carlo (QMC) is an extremely powerful method to treat many-body systems. Usually quantum Monte Carlo has been applied in cases where the interaction potential has a simple analytic form, like the 1/r Coulomb potential. However, in a complicated environment as in a semiconductor heterostructure, the evaluation of the interaction itself becomes a non-trivial problem. Obtaining the potential from any grid-based finite-difference method, for every walker and every step is unfeasible. We demonstrate an alternative approach of solving the Poisson equation by a classical Monte Carlo within the overall quantum Monte Carlo scheme. We have developed a modified ''Walk On Spheres'' algorithm using Green's function techniques, which can efficiently account for the interaction energy of walker configurations, typical of quantum Monte Carlo algorithms. This stochastically obtained potential can be easily incorporated within popular quantum Monte Carlo techniques like variational Monte Carlo (VMC) or diffusion Monte Carlo (DMC). We demonstrate the validity of this method by studying a simple problem, the polarization of a helium atom in the electric field of an infinite capacitor.

  11. Efficiency and accuracy of Monte Carlo (importance) sampling

    NARCIS (Netherlands)

    Waarts, P.H.

    2003-01-01

    Monte Carlo Analysis is often regarded as the most simple and accurate reliability method. Be-sides it is the most transparent method. The only problem is the accuracy in correlation with the efficiency. Monte Carlo gets less efficient or less accurate when very low probabilities are to be computed

  12. The Monte Carlo Method. Popular Lectures in Mathematics.

    Science.gov (United States)

    Sobol', I. M.

    The Monte Carlo Method is a method of approximately solving mathematical and physical problems by the simulation of random quantities. The principal goal of this booklet is to suggest to specialists in all areas that they will encounter problems which can be solved by the Monte Carlo Method. Part I of the booklet discusses the simulation of random…

  13. Forest canopy BRDF simulation using Monte Carlo method

    NARCIS (Netherlands)

    Huang, J.; Wu, B.; Zeng, Y.; Tian, Y.

    2006-01-01

    Monte Carlo method is a random statistic method, which has been widely used to simulate the Bidirectional Reflectance Distribution Function (BRDF) of vegetation canopy in the field of visible remote sensing. The random process between photons and forest canopy was designed using Monte Carlo method.

  14. QWalk: A Quantum Monte Carlo Program for Electronic Structure

    CERN Document Server

    Wagner, Lucas K; Mitas, Lubos

    2007-01-01

    We describe QWalk, a new computational package capable of performing Quantum Monte Carlo electronic structure calculations for molecules and solids with many electrons. We describe the structure of the program and its implementation of Quantum Monte Carlo methods. It is open-source, licensed under the GPL, and available at the web site http://www.qwalk.org

  15. QUANTUM MONTE-CARLO SIMULATIONS - ALGORITHMS, LIMITATIONS AND APPLICATIONS

    NARCIS (Netherlands)

    DERAEDT, H

    1992-01-01

    A survey is given of Quantum Monte Carlo methods currently used to simulate quantum lattice models. The formalisms employed to construct the simulation algorithms are sketched. The origin of fundamental (minus sign) problems which limit the applicability of the Quantum Monte Carlo approach is shown

  16. Recent Developments in Quantum Monte Carlo: Methods and Applications

    Science.gov (United States)

    Aspuru-Guzik, Alan; Austin, Brian; Domin, Dominik; Galek, Peter T. A.; Handy, Nicholas; Prasad, Rajendra; Salomon-Ferrer, Romelia; Umezawa, Naoto; Lester, William A.

    2007-12-01

    The quantum Monte Carlo method in the diffusion Monte Carlo form has become recognized for its capability of describing the electronic structure of atomic, molecular and condensed matter systems to high accuracy. This talk will briefly outline the method with emphasis on recent developments connected with trial function construction, linear scaling, and applications to selected systems.

  17. Sensitivity of Monte Carlo simulations to input distributions

    Energy Technology Data Exchange (ETDEWEB)

    RamoRao, B. S.; Srikanta Mishra, S.; McNeish, J.; Andrews, R. W.

    2001-07-01

    The sensitivity of the results of a Monte Carlo simulation to the shapes and moments of the probability distributions of the input variables is studied. An economical computational scheme is presented as an alternative to the replicate Monte Carlo simulations and is explained with an illustrative example. (Author) 4 refs.

  18. CERN Summer Student Report 2016 Monte Carlo Data Base Improvement

    CERN Document Server

    Caciulescu, Alexandru Razvan

    2016-01-01

    During my Summer Student project I worked on improving the Monte Carlo Data Base and MonALISA services for the ALICE Collaboration. The project included learning the infrastructure for tracking and monitoring of the Monte Carlo productions as well as developing a new RESTful API for seamless integration with the JIRA issue tracking framework.

  19. Practical schemes for accurate forces in quantum Monte Carlo

    NARCIS (Netherlands)

    Moroni, S.; Saccani, S.; Filippi, C.

    2014-01-01

    While the computation of interatomic forces has become a well-established practice within variational Monte Carlo (VMC), the use of the more accurate Fixed-Node Diffusion Monte Carlo (DMC) method is still largely limited to the computation of total energies on structures obtained at a lower level of

  20. Micromamíferos del Pleistoceno Medio y Pleistoceno Superior en el Valle del Jarama: yacimientos de Valdocarros y HAT (Madrid, España

    Directory of Open Access Journals (Sweden)

    Sesé, C.

    2011-06-01

    >Oryctolagus cuniculus; y en HAT: soricomorfos: Soricidae indet.; roedores: Eliomys quercinus, Apodemus sp., Arvi cola aff. sapidus y Microtus cf. cabrerae; y lagomorfos: cf. Oryctolagus sp. La asociación del yacimiento de Valdocarros, por su composición y por el estadio evolutivo de Microtus brecciensis, se sitúa en el Pleistoceno Medio avanzado pero no final. La presencia de Microtus cf. cabrerae en el yacimiento de HAT hace que se adscriba al Pleistoceno Superior. Ambas asociaciones indican unas condiciones paleo- ambientales de clima templado y un buen desarrollo de la cobertura vegetal con zonas boscosas y zonas abiertas con vegetación arbustiva, ribereña y praderas.

  1. Commensurabilities between ETNOs: a Monte Carlo survey

    CERN Document Server

    Marcos, C de la Fuente

    2016-01-01

    Many asteroids in the main and trans-Neptunian belts are trapped in mean motion resonances with Jupiter and Neptune, respectively. As a side effect, they experience accidental commensurabilities among themselves. These commensurabilities define characteristic patterns that can be used to trace the source of the observed resonant behaviour. Here, we explore systematically the existence of commensurabilities between the known ETNOs using their heliocentric and barycentric semimajor axes, their uncertainties, and Monte Carlo techniques. We find that the commensurability patterns present in the known ETNO population resemble those found in the main and trans-Neptunian belts. Although based on small number statistics, such patterns can only be properly explained if most, if not all, of the known ETNOs are subjected to the resonant gravitational perturbations of yet undetected trans-Plutonian planets. We show explicitly that some of the statistically significant commensurabilities are compatible with the Planet Nin...

  2. Monte Carlo exploration of warped Higgsless models

    Energy Technology Data Exchange (ETDEWEB)

    Hewett, JoAnne L.; Lillie, Benjamin; Rizzo, Thomas Gerard [Stanford Linear Accelerator Center, 2575 Sand Hill Rd., Menlo Park, CA, 94025 (United States)]. E-mail: rizzo@slac.stanford.edu

    2004-10-01

    We have performed a detailed Monte Carlo exploration of the parameter space for a warped Higgsless model of electroweak symmetry breaking in 5 dimensions. This model is based on the SU(2){sub L} x SU(2){sub R} x U(1){sub B-L} gauge group in an AdS{sub 5} bulk with arbitrary gauge kinetic terms on both the Planck and TeV branes. Constraints arising from precision electroweak measurements and collider data are found to be relatively easy to satisfy. We show, however, that the additional requirement of perturbative unitarity up to the cut-off, {approx_equal} 10 TeV, in W{sub L}{sup +}W{sub L}{sup -} elastic scattering in the absence of dangerous tachyons eliminates all models. If successful models of this class exist, they must be highly fine-tuned. (author)

  3. Monte Carlo Exploration of Warped Higgsless Models

    CERN Document Server

    Hewett, J L; Rizzo, T G

    2004-01-01

    We have performed a detailed Monte Carlo exploration of the parameter space for a warped Higgsless model of electroweak symmetry breaking in 5 dimensions. This model is based on the $SU(2)_L\\times SU(2)_R\\times U(1)_{B-L}$ gauge group in an AdS$_5$ bulk with arbitrary gauge kinetic terms on both the Planck and TeV branes. Constraints arising from precision electroweak measurements and collider data are found to be relatively easy to satisfy. We show, however, that the additional requirement of perturbative unitarity up to the cut-off, $\\simeq 10$ TeV, in $W_L^+W_L^-$ elastic scattering in the absence of dangerous tachyons eliminates all models. If successful models of this class exist, they must be highly fine-tuned.

  4. Experimental Monte Carlo Quantum Process Certification

    CERN Document Server

    Steffen, L; Fedorov, A; Baur, M; Wallraff, A

    2012-01-01

    Experimental implementations of quantum information processing have now reached a level of sophistication where quantum process tomography is impractical. The number of experimental settings as well as the computational cost of the data post-processing now translates to days of effort to characterize even experiments with as few as 8 qubits. Recently a more practical approach to determine the fidelity of an experimental quantum process has been proposed, where the experimental data is compared directly to an ideal process using Monte Carlo sampling. Here we present an experimental implementation of this scheme in a circuit quantum electrodynamics setup to determine the fidelity of two qubit gates, such as the cphase and the cnot gate, and three qubit gates, such as the Toffoli gate and two sequential cphase gates.

  5. Variable length trajectory compressible hybrid Monte Carlo

    CERN Document Server

    Nishimura, Akihiko

    2016-01-01

    Hybrid Monte Carlo (HMC) generates samples from a prescribed probability distribution in a configuration space by simulating Hamiltonian dynamics, followed by the Metropolis (-Hastings) acceptance/rejection step. Compressible HMC (CHMC) generalizes HMC to a situation in which the dynamics is reversible but not necessarily Hamiltonian. This article presents a framework to further extend the algorithm. Within the existing framework, each trajectory of the dynamics must be integrated for the same amount of (random) time to generate a valid Metropolis proposal. Our generalized acceptance/rejection mechanism allows a more deliberate choice of the integration time for each trajectory. The proposed algorithm in particular enables an effective application of variable step size integrators to HMC-type sampling algorithms based on reversible dynamics. The potential of our framework is further demonstrated by another extension of HMC which reduces the wasted computations due to unstable numerical approximations and corr...

  6. On nonlinear Markov chain Monte Carlo

    CERN Document Server

    Andrieu, Christophe; Doucet, Arnaud; Del Moral, Pierre; 10.3150/10-BEJ307

    2011-01-01

    Let $\\mathscr{P}(E)$ be the space of probability measures on a measurable space $(E,\\mathcal{E})$. In this paper we introduce a class of nonlinear Markov chain Monte Carlo (MCMC) methods for simulating from a probability measure $\\pi\\in\\mathscr{P}(E)$. Nonlinear Markov kernels (see [Feynman--Kac Formulae: Genealogical and Interacting Particle Systems with Applications (2004) Springer]) $K:\\mathscr{P}(E)\\times E\\rightarrow\\mathscr{P}(E)$ can be constructed to, in some sense, improve over MCMC methods. However, such nonlinear kernels cannot be simulated exactly, so approximations of the nonlinear kernels are constructed using auxiliary or potentially self-interacting chains. Several nonlinear kernels are presented and it is demonstrated that, under some conditions, the associated approximations exhibit a strong law of large numbers; our proof technique is via the Poisson equation and Foster--Lyapunov conditions. We investigate the performance of our approximations with some simulations.

  7. Monte Carlo Implementation of Polarized Hadronization

    CERN Document Server

    Matevosyan, Hrayr H; Thomas, Anthony W

    2016-01-01

    We study the polarized quark hadronization in a Monte Carlo (MC) framework based on the recent extension of the quark-jet framework, where a self-consistent treatment of the quark polarization transfer in a sequential hadronization picture has been presented. Here, we first adopt this approach for MC simulations of hadronization process with finite number of produced hadrons, expressing the relevant probabilities in terms of the eight leading twist quark-to-quark transverse momentum dependent (TMD) splitting functions (SFs) for elementary $q \\to q'+h$ transition. We present explicit expressions for the unpolarized and Collins fragmentation functions (FFs) of unpolarized hadrons emitted at rank two. Further, we demonstrate that all the current spectator-type model calculations of the leading twist quark-to-quark TMD SFs violate the positivity constraints, and propose quark model based ansatz for these input functions that circumvents the problem. We validate our MC framework by explicitly proving the absence o...

  8. Lunar Regolith Albedos Using Monte Carlos

    Science.gov (United States)

    Wilson, T. L.; Andersen, V.; Pinsky, L. S.

    2003-01-01

    The analysis of planetary regoliths for their backscatter albedos produced by cosmic rays (CRs) is important for space exploration and its potential contributions to science investigations in fundamental physics and astrophysics. Albedos affect all such experiments and the personnel that operate them. Groups have analyzed the production rates of various particles and elemental species by planetary surfaces when bombarded with Galactic CR fluxes, both theoretically and by means of various transport codes, some of which have emphasized neutrons. Here we report on the preliminary results of our current Monte Carlo investigation into the production of charged particles, neutrons, and neutrinos by the lunar surface using FLUKA. In contrast to previous work, the effects of charm are now included.

  9. Gas discharges modeling by Monte Carlo technique

    Directory of Open Access Journals (Sweden)

    Savić Marija

    2010-01-01

    Full Text Available The basic assumption of the Townsend theory - that ions produce secondary electrons - is valid only in a very narrow range of the reduced electric field E/N. In accordance with the revised Townsend theory that was suggested by Phelps and Petrović, secondary electrons are produced in collisions of ions, fast neutrals, metastable atoms or photons with the cathode, or in gas phase ionizations by fast neutrals. In this paper we tried to build up a Monte Carlo code that can be used to calculate secondary electron yields for different types of particles. The obtained results are in good agreement with the analytical results of Phelps and. Petrović [Plasma Sourc. Sci. Technol. 8 (1999 R1].

  10. Helminthiases in Montes Claros. Preliminary survey

    Directory of Open Access Journals (Sweden)

    Rina Girard Kaminsky

    1976-04-01

    Full Text Available A preliminary survey was conducted for the presence of helminths in the city of Montes Claros, M. G., Brazil. Three groups of persons were examined by the direct smear, Kato thick film and MIFC techniques; one group by direct smear and Kato only. General findings were: a high prevalence of hookworm, followed by ascariasis, S. mansoni, S. stercoralis and very light infections with T. trichiurá. E. vermicularis and H. nana were ranking parasites at an orphanage, with some hookworm and S. mansoni infections as well. At a pig slaughter house, the dominant parasites were hookworm and S. mansoni. Pig cysticercosis was an incidental finding worth mentioning for the health hazard it represents for humans as well as an economic loss. From the comparative results between the Kato and the MIF the former proved itself again as a more sensitive and reliable concentration method for helminth eggs, of low cost and easy performance.

  11. Morse Monte Carlo Radiation Transport Code System

    Energy Technology Data Exchange (ETDEWEB)

    Emmett, M.B.

    1975-02-01

    The report contains sections containing descriptions of the MORSE and PICTURE codes, input descriptions, sample problems, deviations of the physical equations and explanations of the various error messages. The MORSE code is a multipurpose neutron and gamma-ray transport Monte Carlo code. Time dependence for both shielding and criticality problems is provided. General three-dimensional geometry may be used with an albedo option available at any material surface. The PICTURE code provide aid in preparing correct input data for the combinatorial geometry package CG. It provides a printed view of arbitrary two-dimensional slices through the geometry. By inspecting these pictures one may determine if the geometry specified by the input cards is indeed the desired geometry. 23 refs. (WRF)

  12. Variational Monte Carlo study of pentaquark states

    Energy Technology Data Exchange (ETDEWEB)

    Mark W. Paris

    2005-07-01

    Accurate numerical solution of the five-body Schrodinger equation is effected via variational Monte Carlo. The spectrum is assumed to exhibit a narrow resonance with strangeness S=+1. A fully antisymmetrized and pair-correlated five-quark wave function is obtained for the assumed non-relativistic Hamiltonian which has spin, isospin, and color dependent pair interactions and many-body confining terms which are fixed by the non-exotic spectra. Gauge field dynamics are modeled via flux tube exchange factors. The energy determined for the ground states with J=1/2 and negative (positive) parity is 2.22 GeV (2.50 GeV). A lower energy negative parity state is consistent with recent lattice results. The short-range structure of the state is analyzed via its diquark content.

  13. Monte Carlo simulation of neutron scattering instruments

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, P.A.; Daemen, L.L.; Hjelm, R.P. Jr.

    1998-12-01

    A code package consisting of the Monte Carlo Library MCLIB, the executing code MC{_}RUN, the web application MC{_}Web, and various ancillary codes is proposed as an open standard for simulation of neutron scattering instruments. The architecture of the package includes structures to define surfaces, regions, and optical elements contained in regions. A particle is defined by its vector position and velocity, its time of flight, its mass and charge, and a polarization vector. The MC{_}RUN code handles neutron transport and bookkeeping, while the action on the neutron within any region is computed using algorithms that may be deterministic, probabilistic, or a combination. Complete versatility is possible because the existing library may be supplemented by any procedures a user is able to code. Some examples are shown.

  14. Accurate barrier heights using diffusion Monte Carlo

    CERN Document Server

    Krongchon, Kittithat; Wagner, Lucas K

    2016-01-01

    Fixed node diffusion Monte Carlo (DMC) has been performed on a test set of forward and reverse barrier heights for 19 non-hydrogen-transfer reactions, and the nodal error has been assessed. The DMC results are robust to changes in the nodal surface, as assessed by using different mean-field techniques to generate single determinant wave functions. Using these single determinant nodal surfaces, DMC results in errors of 1.5(5) kcal/mol on barrier heights. Using the large data set of DMC energies, we attempted to find good descriptors of the fixed node error. It does not correlate with a number of descriptors including change in density, but does correlate with the gap between the highest occupied and lowest unoccupied orbital energies in the mean-field calculation.

  15. Atomistic Monte Carlo simulation of lipid membranes

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Sklenar, Heinz

    2014-01-01

    Biological membranes are complex assemblies of many different molecules of which analysis demands a variety of experimental and computational approaches. In this article, we explain challenges and advantages of atomistic Monte Carlo (MC) simulation of lipid membranes. We provide an introduction......, as assessed by calculation of molecular energies and entropies. We also show transition from a crystalline-like to a fluid DPPC bilayer by the CBC local-move MC method, as indicated by the electron density profile, head group orientation, area per lipid, and whole-lipid displacements. We discuss the potential...... of local-move MC methods in combination with molecular dynamics simulations, for example, for studying multi-component lipid membranes containing cholesterol....

  16. Geometric Monte Carlo and Black Janus Geometries

    CERN Document Server

    Bak, Dongsu; Kim, Kyung Kiu; Min, Hyunsoo; Song, Jeong-Pil

    2016-01-01

    We describe an application of the Monte Carlo method to the Janus deformation of the black brane background. We present numerical results for three and five dimensional black Janus geometries with planar and spherical interfaces. In particular, we argue that the 5D geometry with a spherical interface has an application in understanding the finite temperature bag-like QCD model via the AdS/CFT correspondence. The accuracy and convergence of the algorithm are evaluated with respect to the grid spacing. The systematic errors of the method are determined using an exact solution of 3D black Janus. This numerical approach for solving linear problems is unaffected initial guess of a trial solution and can handle an arbitrary geometry under various boundary conditions in the presence of source fields.

  17. Modeling neutron guides using Monte Carlo simulations

    CERN Document Server

    Wang, D Q; Crow, M L; Wang, X L; Lee, W T; Hubbard, C R

    2002-01-01

    Four neutron guide geometries, straight, converging, diverging and curved, were characterized using Monte Carlo ray-tracing simulations. The main areas of interest are the transmission of the guides at various neutron energies and the intrinsic time-of-flight (TOF) peak broadening. Use of a delta-function time pulse from a uniform Lambert neutron source allows one to quantitatively simulate the effect of guides' geometry on the TOF peak broadening. With a converging guide, the intensity and the beam divergence increases while the TOF peak width decreases compared with that of a straight guide. By contrast, use of a diverging guide decreases the intensity and the beam divergence, and broadens the width (in TOF) of the transmitted neutron pulse.

  18. Monte Carlo modelling of TRIGA research reactor

    Science.gov (United States)

    El Bakkari, B.; Nacir, B.; El Bardouni, T.; El Younoussi, C.; Merroun, O.; Htet, A.; Boulaich, Y.; Zoubair, M.; Boukhal, H.; Chakir, M.

    2010-10-01

    The Moroccan 2 MW TRIGA MARK II research reactor at Centre des Etudes Nucléaires de la Maâmora (CENM) achieved initial criticality on May 2, 2007. The reactor is designed to effectively implement the various fields of basic nuclear research, manpower training, and production of radioisotopes for their use in agriculture, industry, and medicine. This study deals with the neutronic analysis of the 2-MW TRIGA MARK II research reactor at CENM and validation of the results by comparisons with the experimental, operational, and available final safety analysis report (FSAR) values. The study was prepared in collaboration between the Laboratory of Radiation and Nuclear Systems (ERSN-LMR) from Faculty of Sciences of Tetuan (Morocco) and CENM. The 3-D continuous energy Monte Carlo code MCNP (version 5) was used to develop a versatile and accurate full model of the TRIGA core. The model represents in detailed all components of the core with literally no physical approximation. Continuous energy cross-section data from the more recent nuclear data evaluations (ENDF/B-VI.8, ENDF/B-VII.0, JEFF-3.1, and JENDL-3.3) as well as S( α, β) thermal neutron scattering functions distributed with the MCNP code were used. The cross-section libraries were generated by using the NJOY99 system updated to its more recent patch file "up259". The consistency and accuracy of both the Monte Carlo simulation and neutron transport physics were established by benchmarking the TRIGA experiments. Core excess reactivity, total and integral control rods worth as well as power peaking factors were used in the validation process. Results of calculations are analysed and discussed.

  19. Accelerated GPU based SPECT Monte Carlo simulations.

    Science.gov (United States)

    Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

    2016-06-07

    Monte Carlo (MC) modelling is widely used in the field of single photon emission computed tomography (SPECT) as it is a reliable technique to simulate very high quality scans. This technique provides very accurate modelling of the radiation transport and particle interactions in a heterogeneous medium. Various MC codes exist for nuclear medicine imaging simulations. Recently, new strategies exploiting the computing capabilities of graphical processing units (GPU) have been proposed. This work aims at evaluating the accuracy of such GPU implementation strategies in comparison to standard MC codes in the context of SPECT imaging. GATE was considered the reference MC toolkit and used to evaluate the performance of newly developed GPU Geant4-based Monte Carlo simulation (GGEMS) modules for SPECT imaging. Radioisotopes with different photon energies were used with these various CPU and GPU Geant4-based MC codes in order to assess the best strategy for each configuration. Three different isotopes were considered: (99m) Tc, (111)In and (131)I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational

  20. Accelerated GPU based SPECT Monte Carlo simulations

    Science.gov (United States)

    Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

    2016-06-01

    Monte Carlo (MC) modelling is widely used in the field of single photon emission computed tomography (SPECT) as it is a reliable technique to simulate very high quality scans. This technique provides very accurate modelling of the radiation transport and particle interactions in a heterogeneous medium. Various MC codes exist for nuclear medicine imaging simulations. Recently, new strategies exploiting the computing capabilities of graphical processing units (GPU) have been proposed. This work aims at evaluating the accuracy of such GPU implementation strategies in comparison to standard MC codes in the context of SPECT imaging. GATE was considered the reference MC toolkit and used to evaluate the performance of newly developed GPU Geant4-based Monte Carlo simulation (GGEMS) modules for SPECT imaging. Radioisotopes with different photon energies were used with these various CPU and GPU Geant4-based MC codes in order to assess the best strategy for each configuration. Three different isotopes were considered: 99m Tc, 111In and 131I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational efficiency

  1. Fission Matrix Capability for MCNP Monte Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Carney, Sean E. [Los Alamos National Laboratory; Brown, Forrest B. [Los Alamos National Laboratory; Kiedrowski, Brian C. [Los Alamos National Laboratory; Martin, William R. [Los Alamos National Laboratory

    2012-09-05

    In a Monte Carlo criticality calculation, before the tallying of quantities can begin, a converged fission source (the fundamental eigenvector of the fission kernel) is required. Tallies of interest may include powers, absorption rates, leakage rates, or the multiplication factor (the fundamental eigenvalue of the fission kernel, k{sub eff}). Just as in the power iteration method of linear algebra, if the dominance ratio (the ratio of the first and zeroth eigenvalues) is high, many iterations of neutron history simulations are required to isolate the fundamental mode of the problem. Optically large systems have large dominance ratios, and systems containing poor neutron communication between regions are also slow to converge. The fission matrix method, implemented into MCNP[1], addresses these problems. When Monte Carlo random walk from a source is executed, the fission kernel is stochastically applied to the source. Random numbers are used for: distances to collision, reaction types, scattering physics, fission reactions, etc. This method is used because the fission kernel is a complex, 7-dimensional operator that is not explicitly known. Deterministic methods use approximations/discretization in energy, space, and direction to the kernel. Consequently, they are faster. Monte Carlo directly simulates the physics, which necessitates the use of random sampling. Because of this statistical noise, common convergence acceleration methods used in deterministic methods do not work. In the fission matrix method, we are using the random walk information not only to build the next-iteration fission source, but also a spatially-averaged fission kernel. Just like in deterministic methods, this involves approximation and discretization. The approximation is the tallying of the spatially-discretized fission kernel with an incorrect fission source. We address this by making the spatial mesh fine enough that this error is negligible. As a consequence of discretization we get a

  2. Vectorized Monte Carlo methods for reactor lattice analysis

    Science.gov (United States)

    Brown, F. B.

    1984-01-01

    Some of the new computational methods and equivalent mathematical representations of physics models used in the MCV code, a vectorized continuous-enery Monte Carlo code for use on the CYBER-205 computer are discussed. While the principal application of MCV is the neutronics analysis of repeating reactor lattices, the new methods used in MCV should be generally useful for vectorizing Monte Carlo for other applications. For background, a brief overview of the vector processing features of the CYBER-205 is included, followed by a discussion of the fundamentals of Monte Carlo vectorization. The physics models used in the MCV vectorized Monte Carlo code are then summarized. The new methods used in scattering analysis are presented along with details of several key, highly specialized computational routines. Finally, speedups relative to CDC-7600 scalar Monte Carlo are discussed.

  3. Quantum Monte Carlo methods algorithms for lattice models

    CERN Document Server

    Gubernatis, James; Werner, Philipp

    2016-01-01

    Featuring detailed explanations of the major algorithms used in quantum Monte Carlo simulations, this is the first textbook of its kind to provide a pedagogical overview of the field and its applications. The book provides a comprehensive introduction to the Monte Carlo method, its use, and its foundations, and examines algorithms for the simulation of quantum many-body lattice problems at finite and zero temperature. These algorithms include continuous-time loop and cluster algorithms for quantum spins, determinant methods for simulating fermions, power methods for computing ground and excited states, and the variational Monte Carlo method. Also discussed are continuous-time algorithms for quantum impurity models and their use within dynamical mean-field theory, along with algorithms for analytically continuing imaginary-time quantum Monte Carlo data. The parallelization of Monte Carlo simulations is also addressed. This is an essential resource for graduate students, teachers, and researchers interested in ...

  4. Monte-Carlo Simulation of Ising Model%Ising 模型的Monte-Carlo模拟

    Institute of Scientific and Technical Information of China (English)

    吴国军; 胡经国

    2000-01-01

    在平面四角点阵上,以Ising模型为框架,在IBM-PC机上用Mont e-Carlo方法模拟了螺旋边界、半自由边界及自由边界条件下铁磁系统的相图,并与周期性边界条件下的结果作了比较.

  5. Monte Carlo 2000 Conference : Advanced Monte Carlo for Radiation Physics, Particle Transport Simulation and Applications

    CERN Document Server

    Baräo, Fernando; Nakagawa, Masayuki; Távora, Luis; Vaz, Pedro

    2001-01-01

    This book focusses on the state of the art of Monte Carlo methods in radiation physics and particle transport simulation and applications, the latter involving in particular, the use and development of electron--gamma, neutron--gamma and hadronic codes. Besides the basic theory and the methods employed, special attention is paid to algorithm development for modeling, and the analysis of experiments and measurements in a variety of fields ranging from particle to medical physics.

  6. Conocimiento campesino, el "monte santiagueño" como recurso forrajero Peasant knowledge, the "monte santiagueño" as fodder resource

    Directory of Open Access Journals (Sweden)

    Patricia Riat

    2012-12-01

    Full Text Available El conocimiento campesino sobre el entorno natural puede ser interpretado a través de su relación cotidiana con el monte, donde gran parte de sus necesidades de subsistencia están abastecidas por este. A modo de aproximación se toma el conocimiento sobre el uso de las plantas nativas, y teniendo en cuenta el principal modo de subsistencia, la ganadería, se analiza el conocimiento de plantas alimenticias para el ganado. La zona de estudio se encuentra en la región fitogeográfica chaqueña. Abarca el norte del Pueblo Los Juríes, entre el departamento General Taboada y el departamento Brigadier Felipe Ibarra, al centro-este de la Provincia de Santiago del Estero. La producción ganadera se hace en pequeña escala y en forma extensiva, siendo los sistemas ganaderos netamente de subsistencia. Durante un año se efectuaron tres viajes de campaña en la zona. En el primer viaje fue presentado el proyecto ante la comunidad y se obtuvo el consentimiento informado para el desarrollo del mismo y publicación de los resultados. Los datos fueron obtenidos a través de técnicas etnobotánicas cualitativas a fin de relevar el conocimiento y prácticas acerca de los recursos vegetales. Se relevaron treinta y cinco plantas reconocidas y usadas localmente como forrajeras y el tipo de ganado asociado. Los resultados expuestos demuestran la importancia de los saberes locales concernientes a especies vegetales nativas útiles en la alimentación del ganado. A pesar del relativamente corto tiempo de asentamiento de la población campesina en la zona, sus conocimientos, provenientes de regiones lindantes y adquiridos in situ, demuestran un alto grado de observación y comprensión del ecosistema en el cual se hallan inmersos.Peasant knowledge about natural environment could be interpreted through their daily relationship with the "monte", where a big part of their needs of subsistence are supplied by it. Considering the primary mode of subsistence, animal

  7. Del Derecho laboral al Derecho del trabajo

    OpenAIRE

    Jaramillo Jassir, Ivan Daniel

    2011-01-01

    El Derecho Laboral hijo de la revolución industrial, calificado como el acontecimiento jurídico del siglo XX, reduce su ámbito de estudio al trabajo subordinado. Los cambios del sistema de producción superan la centralidad del contrato de trabajo subordinado a tiempo indeterminado, situación que demanda ampliación del ámbito de aplicación subjetivo y objetivo de la materia, dando paso al Derecho del Trabajo que se ocupa del trabajo en todas sus modalidades como fuente de ingreso para satisfac...

  8. 欧式期权定价的Monte-Carlo方法%Monte-Carlo methods for Pricing European-style options

    Institute of Scientific and Technical Information of China (English)

    张丽虹

    2015-01-01

    We discuss Monte-Carlo methods for pricing European options.Based on the famous Black-Scholes model,we first discuss the Monte-Carlo simulation method to pricing standard European options according to Risk neutral theory.Methods to improve the Monte-Carlo simulation performance including introducing control variates and antithetic variates are also discussed.Finally we apply the proposed Monte-Carlo methods to price the European binary options,European lookback options and European Asian options.%讨论各种欧式期权价格的Monte-Carlo方法。根据Black-Scholes期权定价模型以及风险中性理论,首先详细地讨论如何利用Monte-Carlo方法来计算标准欧式期权价格;然后讨论如何引入控制变量以及对称变量来提高Monte-Carlo方法的精确性;最后用Monte-Carlo方法来计算标准欧式期权、欧式—两值期权、欧式—回望期权以及欧式—亚式期权的价格,并讨论相关方法的优缺点。

  9. Cuento: Monte de fuego y oscuridad

    Directory of Open Access Journals (Sweden)

    José Puben

    1967-03-01

    Full Text Available Se tendió sobre el prado, bajo la sombra de un árbol, tal como lo habían hecho otras personas. Mientras descansaba veía corretear un grupo de niños, en torno a una roca que adornaba el parque. Relativamente cerca de donde estaba una fila continua de carros se deslizaba, en forma tranquila y ordenada, deteniéndose para el cambio de las luces del semáforo.

  10. Obtención de un filtrante de anís de monte (Tagetes filifolia Lag. edulcorado con hojas de estevia (Stevia rebaudiana Bertoni

    Directory of Open Access Journals (Sweden)

    Carlos Millones

    2014-01-01

    Full Text Available El presente trabajo de investigación se realizó para determinar el segmento de la planta de anís de monte yformulación apropiada de anís de monte y hojas de estevia en la elaboración de un filtrante edulcorado; para locual se emplearon plantas de anís demonte y hojas de estevia, las cuales fueron lavadas, desinfectadas,secadas a 65°C, molidas, tamizadas y envasadas; posteriormente se realizaron las formulaciones del filtrantecon anís de monte y hojas de estevia (90:10; 85:15; 80:20 y 75:25, empleandoun gramo por muestraenvasadas en papel termosellable; los resultados del color, tiempo de infusión y pH; asimismo, lasevaluaciones organolépticas de olor, sabor, dulzor y aspecto general se procesaron empleando el paqueteestadístico SAS (Statistical Analysis System for Window V8. Los resultados mostraron que empleando 80 a85% hojas + flores de anís de monte y 15 a 20% de hojas de estevia se obtiene un filtrante edulcorado conadecuadas características organolépticas.

  11. LA SARNA PLATEADA (Helminthosporium solani (DUR. & MONT., UNA ENFERMEDAD DE CRECIENTE IMPORTANCIA EN PAPA

    Directory of Open Access Journals (Sweden)

    Lili Marijke Hofmann

    2009-01-01

    Full Text Available El presente trabajo es una revisión bibliográfica sobre la enfermedad de la sarna plateada y su agente causal Helminthosporium solani (Dur. & Mont. en el cultivo de la papa (Solanum tuberosum L.. Desde hace 15 años, esta enfermedad juega un papel cada vez más importante en la producción de este tubérculo. Esta revisión abarca la importancia económica de la enfermedad, su detección en los tubérculos y en el suelo, y su aislamiento. También se desarrolla el tema del ciclo de vida de H. solani, el cual todavía no se conoce por completo. Además, se incluye el control de la sarna plateada mediante fungicidas, prácticas del manejo del cultivo en el campo y en almacenamiento, uso de antagonistas y a través de la mejora genética.

  12. Iterative acceleration methods for Monte Carlo and deterministic criticality calculations

    Energy Technology Data Exchange (ETDEWEB)

    Urbatsch, T.J.

    1995-11-01

    If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors.

  13. Evaluación del modelo WEPP para predecir la erosión hídrica en pastizales semiáridos del noreste de la Patagonia Evaluation of the WEPP model to predict soil erosion in northeastern Patagonian rangelands

    Directory of Open Access Journals (Sweden)

    Marcelo P Chartier

    2010-07-01

    Full Text Available Los modelos matemáticos son herramientas útiles para la predicción de las pérdidas de suelo por erosión hídrica. El desarrollo reciente del modelo WEPP y su utilización para evaluar los riesgos de erosión en pastizales naturales ha significado un avance interesante en el campo de la erosión y la conservación de suelos de estos ecosistemas. En este trabajo examinamos la eficiencia del modelo WEPP para predecir los procesos hidrológicos y de erosión del suelo en los pastizales naturales semiáridos del noreste de la provincia de Chubut. Se identificaron tres comunidades de plantas ubicadas a lo largo de un gradiente de degradación del suelo: estepa herbácea con arbustos aislados (EH, estepa herbáceo-arbustiva (EHA y estepa arbustiva degradada (EA. En cada una de estas comunidades se aplicó una lluvia simulada (100 mm h-1 durante 30 min sobre parcelas de 1 m² (0,6 x 1,67 m y se colectó el escurrimiento y los sedimentos totales. A partir de los datos de la condición superficial de cada parcela se estimó el escurrimiento y la producción de sedimentos mediante el modelo WEPP. En este trabajo se observó una baja eficiencia del modelo WEPP para predecir el escurrimiento (Eficiencia, E = 0,14 y la erosión del suelo (E = -0,93. La predicción del escurrimiento y pérdida de suelo del modelo WEPP mostró mayor sensibilidad a cambios en los parámetros de lluvia y pendiente del terreno y una sensibilidad moderada a cambios en la cobertura, textura, erodabilidad del suelo y conductividad hidráulica efectiva. El escurrimiento y la producción de sedimentos estimados por WEPP fueron significativamente diferentes en las distintas comunidades de plantas (p Mathematical models are useful tools to predict soil loss by water erosion. The recent development of the WEPP model and its use in assessing the risks of erosion in rangelands has led to significant advances in the field of erosion and soil conservation of these ecosystems. In this

  14. Helminthiases in Montes Claros. Preliminary survey

    Directory of Open Access Journals (Sweden)

    Rina Girard Kaminsky

    1976-04-01

    Full Text Available A preliminary survey was conducted for the presence of helminths in the city of Montes Claros, M. G., Brazil. Three groups of persons were examined by the direct smear, Kato thick film and MIFC techniques; one group by direct smear and Kato only. General findings were: a high prevalence of hookworm, followed by ascariasis, S. mansoni, S. stercoralis and very light infections with T. trichiurá. E. vermicularis and H. nana were ranking parasites at an orphanage, with some hookworm and S. mansoni infections as well. At a pig slaughter house, the dominant parasites were hookworm and S. mansoni. Pig cysticercosis was an incidental finding worth mentioning for the health hazard it represents for humans as well as an economic loss. From the comparative results between the Kato and the MIF the former proved itself again as a more sensitive and reliable concentration method for helminth eggs, of low cost and easy performance.Um estudo preliminar sobre helmintos foi feito na cidade de Montes Claros, MG, Brasil. Três grupos de pessoas foram examinados pelos métodos direto, de Kato e do MIF e um grupo pelos métodos direto e Kato exclusivamente. Encontrou-se uma alta prevalência de necatorose, seguindo-se ascaríase, S. mansoni, S. stercoralis, e infecções leves pelo T. trichiura. E. vermicularis e H. nana foram osparasitos mais prevalentes num orfanato, com alguns casos de infecção pelo Necator e S. mansoni. Cisticercose dos suinos foi achado incidental e é importante ser mencionada devido ao perigo que representa no plano da Saúde Pública, bem como pela perda econômica que produz. Discutiu-se brevemente a importância do solo na transmissão dos helmintos num clima quente e seco. Da comparação dos métodos de Kato e MIF, o primeiro demonstrou ser o método mais sensível para ovos de helmintos, de baixo custo e fácil preparo.

  15. del cambio

    Directory of Open Access Journals (Sweden)

    Alejandro Canales

    2006-01-01

    Full Text Available El artículo analiza las propuestas y los compromisos en materia de cobertura y de financiamiento en el periodo 2000-2006. En particular, revisa las modificaciones y los ajustes de los tres principales documentos en los que se expresaron las iniciativas: el de la Asociación Nacional de Universidades e Instituciones de Educación Superior, el del equipo de la transición y el programa sectorial. Los resultados muestran que las cifras de atención a la demanda educativa e inversión quedaron lejos de las metas autoimpuestas por el gobierno federal y que será necesario realizar mayores esfuerzos para atender tales desafíos.

  16. Geología ambiental de la laguna de las Perdices, Monte, Buenos Aires, Argentina

    Directory of Open Access Journals (Sweden)

    Nauris Dangavs

    2010-09-01

    Full Text Available El estudio de la laguna de las Perdices abarca tres aspectos: el geolimnológico, el geoambiental y el de remediación. El primero ha consistido en caracterizar el medio físico de un ambiente léntico típico de la Pampasia meridional prácticamente desconocido. El segundo, la evaluación del grado de deterioro natural y la contaminación físico-química y bacteriológica. El tercero propicia las medidas para su recuperación, máxime teniendo en cuenta que el Municipio de Monte pretende transformarla en Reserva Natural. Esta laguna de 11.50 km2, situada en el noreste bonaerense, pertenece a la cuenca de las Lagunas Encadenadas de Monte y fue evaluada con metodología geolimnológica, en base a cartografía, fotografía aérea e imágenes satelitales, nivelaciones, batimetría, freatimetría, perforaciones, muestreo de sedimentos, suelos y aguas. A tal efecto se caracterizaron los aspectos fisiográficos, geomorfológicos, geológicos e hidrológicos de la región y de la laguna. En la cubeta lagunar se estudiaron los depósitos colmatantes, integrados por siete unidades estratigráficas, de las cuales la de mayor interés corresponde a los depósitos actuales, indicadores directos del estado de degradación del ambiente. El régimen hidrológico de la laguna se estableció caracterizando las precipitaciones sobre la superficie lagunar, la evaporación, el escurrimiento superficial y freático, la freatimetría, la interrelación del cuerpo de agua con el agua subterránea, el balance hídrico anual y la dinámica acuática. Las aguas fueron evaluadas en los aspectos físico-químicos, estableciéndose su composición iónica y tipificación química según Maucha y la clasificación limnológica del ambiente acuático. Las determinaciones en agua y sedimentos confirmaron la severa contaminación físico-química y bacteriológica, incompatible con la vida acuática y el uso recreativo, de acuerdo a la normativa vigente. Dicha contaminaci

  17. Information-Geometric Markov Chain Monte Carlo Methods Using Diffusions

    Directory of Open Access Journals (Sweden)

    Samuel Livingstone

    2014-06-01

    Full Text Available Recent work incorporating geometric ideas in Markov chain Monte Carlo is reviewed in order to highlight these advances and their possible application in a range of domains beyond statistics. A full exposition of Markov chains and their use in Monte Carlo simulation for statistical inference and molecular dynamics is provided, with particular emphasis on methods based on Langevin diffusions. After this, geometric concepts in Markov chain Monte Carlo are introduced. A full derivation of the Langevin diffusion on a Riemannian manifold is given, together with a discussion of the appropriate Riemannian metric choice for different problems. A survey of applications is provided, and some open questions are discussed.

  18. The Monte Carlo method the method of statistical trials

    CERN Document Server

    Shreider, YuA

    1966-01-01

    The Monte Carlo Method: The Method of Statistical Trials is a systematic account of the fundamental concepts and techniques of the Monte Carlo method, together with its range of applications. Some of these applications include the computation of definite integrals, neutron physics, and in the investigation of servicing processes. This volume is comprised of seven chapters and begins with an overview of the basic features of the Monte Carlo method and typical examples of its application to simple problems in computational mathematics. The next chapter examines the computation of multi-dimensio

  19. Biodiversity of Myxomycetes from the Monte Desert of Argentina

    Directory of Open Access Journals (Sweden)

    Lado, C.

    2011-06-01

    Full Text Available A biodiversity survey for myxomycetes was carried out in the Monte Desert (Argentina and surrounding areas in November 2006 and late February and March 2007. Specimens were collected in seven different provinces (Catamarca, Jujuy, La Rioja, Salta, San Juan, San Luis and Tucumán, between 23º and 33º S latitude, and a total of 105 localities were sampled. Cacti and succulent plants were the most common type of substrate investigated, but shrubs and herbs characteristic of this biome were also included in the survey. Almost six hundred specimens of myxomycetes from 72 different species in 22 genera were collected either in the field, or from moist chamber cultures prepared with samples of plant material obtained from the same collecting sites. The results include 1 species new to science, Macbrideola andina three more species recently described based on material from this survey, 5 species cited for the first time for the Neotropics, 11 new records for South America and 38 new records for Argentina. Taxonomic comments on rare or unusual species are included and illustrated with photographs by LM and SEM. Data are presented on the development of some species and microenvironmental factors are discussed. An analysis of the biodiversity of myxomycetes in this area, and a comparison with other desert areas, are included.

    Con el objetivo de estudiar la biodiversidad de Myxomycetes en el Desierto de Monte (Argentina y áreas circundantes, se realizó un muestreo en los meses de noviembre de 2006 y febrero y marzo de 2007. Se recolectaron especímenes en un total de 105 localidades pertenecientes a siete provincias (Catamarca, Jujuy, La Rioja, Salta, San Juan, San Luis y Tucumán, situadas entre los paralelos 23º y 33º de latitud sur. Los cactus y plantas suculentas fueron los tipos de sustratos más estudiados, pero también se analizaron arbustos y plantas herbáceas características de este bioma. Casi 600 especímenes de mixomicetes

  20. Projection effects on the FP thickness: a Monte-Carlo exploration

    CERN Document Server

    Lanzoni, B

    2003-01-01

    We study the contribution of projection effects to the intrinsic thickness of the Fundamental Plane (FP) of elliptical galaxies. The Monte-Carlo mapping technique between model properties and observed quantities, introduced by Bertin, Ciotti, and Del Principe (2002), is extended to oblate, two-integrals galaxy models, with non-homologous density profiles, adjustable flattening, variable amount of ordered rotational support, and for which all the relevant projected dynamical quantities can be expressed in fully analytical way. In agreement with previous works, it is found that projection effects move models not exactly parallel to the edge-on FP, by an amount that can be as large as the observed FP thickness. The statistical contribution of projection effects to the FP thickness is however marginal, and the estimated physical FP rms thickness is ~90% of the observed one (when corrected for measurement errors).

  1. Monte Carlo simulations for heavy ion dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Geithner, O.

    2006-07-26

    Water-to-air stopping power ratio (s{sub w,air}) calculations for the ionization chamber dosimetry of clinically relevant ion beams with initial energies from 50 to 450 MeV/u have been performed using the Monte Carlo technique. To simulate the transport of a particle in water the computer code SHIELD-HIT v2 was used which is a substantially modified version of its predecessor SHIELD-HIT v1. The code was partially rewritten, replacing formerly used single precision variables with double precision variables. The lowest particle transport specific energy was decreased from 1 MeV/u down to 10 keV/u by modifying the Bethe- Bloch formula, thus widening its range for medical dosimetry applications. Optional MSTAR and ICRU-73 stopping power data were included. The fragmentation model was verified using all available experimental data and some parameters were adjusted. The present code version shows excellent agreement with experimental data. Additional to the calculations of stopping power ratios, s{sub w,air}, the influence of fragments and I-values on s{sub w,air} for carbon ion beams was investigated. The value of s{sub w,air} deviates as much as 2.3% at the Bragg peak from the recommended by TRS-398 constant value of 1.130 for an energy of 50 MeV/u. (orig.)

  2. Monte Carlo models of dust coagulation

    CERN Document Server

    Zsom, Andras

    2010-01-01

    The thesis deals with the first stage of planet formation, namely dust coagulation from micron to millimeter sizes in circumstellar disks. For the first time, we collect and compile the recent laboratory experiments on dust aggregates into a collision model that can be implemented into dust coagulation models. We put this model into a Monte Carlo code that uses representative particles to simulate dust evolution. Simulations are performed using three different disk models in a local box (0D) located at 1 AU distance from the central star. We find that the dust evolution does not follow the previously assumed growth-fragmentation cycle, but growth is halted by bouncing before the fragmentation regime is reached. We call this the bouncing barrier which is an additional obstacle during the already complex formation process of planetesimals. The absence of the growth-fragmentation cycle and the halted growth has two important consequences for planet formation. 1) It is observed that disk atmospheres are dusty thr...

  3. Monte Carlo simulations of Protein Adsorption

    Science.gov (United States)

    Sharma, Sumit; Kumar, Sanat K.; Belfort, Georges

    2008-03-01

    Amyloidogenic diseases, such as, Alzheimer's are caused by adsorption and aggregation of partially unfolded proteins. Adsorption of proteins is a concern in design of biomedical devices, such as dialysis membranes. Protein adsorption is often accompanied by conformational rearrangements in protein molecules. Such conformational rearrangements are thought to affect many properties of adsorbed protein molecules such as their adhesion strength to the surface, biological activity, and aggregation tendency. It has been experimentally shown that many naturally occurring proteins, upon adsorption to hydrophobic surfaces, undergo a helix to sheet or random coil secondary structural rearrangement. However, to better understand the equilibrium structural complexities of this phenomenon, we have performed Monte Carlo (MC) simulations of adsorption of a four helix bundle, modeled as a lattice protein, and studied the adsorption behavior and equilibrium protein conformations at different temperatures and degrees of surface hydrophobicity. To study the free energy and entropic effects on adsorption, Canonical ensemble MC simulations have been combined with Weighted Histogram Analysis Method(WHAM). Conformational transitions of proteins on surfaces will be discussed as a function of surface hydrophobicity and compared to analogous bulk transitions.

  4. Commensurabilities between ETNOs: a Monte Carlo survey

    Science.gov (United States)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2016-07-01

    Many asteroids in the main and trans-Neptunian belts are trapped in mean motion resonances with Jupiter and Neptune, respectively. As a side effect, they experience accidental commensurabilities among themselves. These commensurabilities define characteristic patterns that can be used to trace the source of the observed resonant behaviour. Here, we explore systematically the existence of commensurabilities between the known ETNOs using their heliocentric and barycentric semimajor axes, their uncertainties, and Monte Carlo techniques. We find that the commensurability patterns present in the known ETNO population resemble those found in the main and trans-Neptunian belts. Although based on small number statistics, such patterns can only be properly explained if most, if not all, of the known ETNOs are subjected to the resonant gravitational perturbations of yet undetected trans-Plutonian planets. We show explicitly that some of the statistically significant commensurabilities are compatible with the Planet Nine hypothesis; in particular, a number of objects may be trapped in the 5:3 and 3:1 mean motion resonances with a putative Planet Nine with semimajor axis ˜700 au.

  5. Diffusion Monte Carlo in internal coordinates.

    Science.gov (United States)

    Petit, Andrew S; McCoy, Anne B

    2013-08-15

    An internal coordinate extension of diffusion Monte Carlo (DMC) is described as a first step toward a generalized reduced-dimensional DMC approach. The method places no constraints on the choice of internal coordinates other than the requirement that they all be independent. Using H(3)(+) and its isotopologues as model systems, the methodology is shown to be capable of successfully describing the ground state properties of molecules that undergo large amplitude, zero-point vibrational motions. Combining the approach developed here with the fixed-node approximation allows vibrationally excited states to be treated. Analysis of the ground state probability distribution is shown to provide important insights into the set of internal coordinates that are less strongly coupled and therefore more suitable for use as the nodal coordinates for the fixed-node DMC calculations. In particular, the curvilinear normal mode coordinates are found to provide reasonable nodal surfaces for the fundamentals of H(2)D(+) and D(2)H(+) despite both molecules being highly fluxional.

  6. A continuation multilevel Monte Carlo algorithm

    KAUST Repository

    Collier, Nathan

    2014-09-05

    We propose a novel Continuation Multi Level Monte Carlo (CMLMC) algorithm for weak approximation of stochastic models. The CMLMC algorithm solves the given approximation problem for a sequence of decreasing tolerances, ending when the required error tolerance is satisfied. CMLMC assumes discretization hierarchies that are defined a priori for each level and are geometrically refined across levels. The actual choice of computational work across levels is based on parametric models for the average cost per sample and the corresponding variance and weak error. These parameters are calibrated using Bayesian estimation, taking particular notice of the deepest levels of the discretization hierarchy, where only few realizations are available to produce the estimates. The resulting CMLMC estimator exhibits a non-trivial splitting between bias and statistical contributions. We also show the asymptotic normality of the statistical error in the MLMC estimator and justify in this way our error estimate that allows prescribing both required accuracy and confidence in the final result. Numerical results substantiate the above results and illustrate the corresponding computational savings in examples that are described in terms of differential equations either driven by random measures or with random coefficients. © 2014, Springer Science+Business Media Dordrecht.

  7. Rare event simulation using Monte Carlo methods

    CERN Document Server

    Rubino, Gerardo

    2009-01-01

    In a probabilistic model, a rare event is an event with a very small probability of occurrence. The forecasting of rare events is a formidable task but is important in many areas. For instance a catastrophic failure in a transport system or in a nuclear power plant, the failure of an information processing system in a bank, or in the communication network of a group of banks, leading to financial losses. Being able to evaluate the probability of rare events is therefore a critical issue. Monte Carlo Methods, the simulation of corresponding models, are used to analyze rare events. This book sets out to present the mathematical tools available for the efficient simulation of rare events. Importance sampling and splitting are presented along with an exposition of how to apply these tools to a variety of fields ranging from performance and dependability evaluation of complex systems, typically in computer science or in telecommunications, to chemical reaction analysis in biology or particle transport in physics. ...

  8. Hot Dog and Butterfly, Nereidum Montes

    Science.gov (United States)

    1999-01-01

    Some of the pictures returned from Mars by the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft show features that--at a glance--resemble familiar, non-geological objects on Earth. For example, the picture above at the left shows several low, relatively flat-topped hills (mesas) on the floor of a broad valley among the mountains of the Nereidum Montes region, northeast of Argyre Planitia. One of the mesas seen here looks like half of a butterfly (upper subframe on right). Another hill looks something like a snail or a hot dog wrapped and baked in a croissant roll (lower subframe on right). These mesas were formed by natural processes and are most likely the eroded remnants of a formerly more extensive layer of bedrock. In the frame on the left, illumination is from the upper left and the scene covers an area 2.7 km (1.7 miles) wide by 6.8 km (4.2 miles) high. The 'butterfly' is about 800 meters (875 yards) in length and the 'hot dog' is about 1 km (0.62 miles) long. Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  9. Monte Carlo simulations for focusing elliptical guides

    Energy Technology Data Exchange (ETDEWEB)

    Valicu, Roxana [FRM2 Garching, Muenchen (Germany); Boeni, Peter [E20, TU Muenchen (Germany)

    2009-07-01

    The aim of the Monte Carlo simulations using McStas Programme was to improve the focusing of the neutron beam existing at PGAA (FRM II) by prolongation of the existing elliptic guide (coated now with supermirrors with m=3) with a new part. First we have tried with an initial length of the additional guide of 7,5cm and coatings for the neutron guide of supermirrors with m=4,5 and 6. The gain (calculated by dividing the intensity in the focal point after adding the guide by the intensity at the focal point with the initial guide) obtained for this coatings indicated that a coating with m=5 would be appropriate for a first trial. The next step was to vary the length of the additional guide for this m value and therefore choosing the appropriate length for the maximal gain. With the m value and the length of the guide fixed we have introduced an aperture 1 cm before the focal point and we have varied the radius of this aperture in order to obtain a focused beam. We have observed a dramatic decrease in the size of the beam in the focal point after introducing this aperture. The simulation results, the gains obtained and the evolution of the beam size will be presented.

  10. Monte Carlo Production Management at CMS

    CERN Document Server

    Boudoul, G.; Pol, A; Srimanobhas, P; Vlimant, J R; Franzoni, Giovanni

    2015-01-01

    The analysis of the LHC data at the Compact Muon Solenoid (CMS) experiment requires the production of a large number of simulated events.During the runI of LHC (2010-2012), CMS has produced over 12 Billion simulated events,organized in approximately sixty different campaigns each emulating specific detector conditions and LHC running conditions (pile up).In order toaggregate the information needed for the configuration and prioritization of the events production,assure the book-keeping and of all the processing requests placed by the physics analysis groups,and to interface with the CMS production infrastructure,the web-based service Monte Carlo Management (McM) has been developed and put in production in 2012.McM is based on recent server infrastructure technology (CherryPy + java) and relies on a CouchDB database back-end.This contribution will coverthe one and half year of operational experience managing samples of simulated events for CMS,the evolution of its functionalitiesand the extension of its capabi...

  11. Parallel Monte Carlo simulation of aerosol dynamics

    KAUST Repository

    Zhou, K.

    2014-01-01

    A highly efficient Monte Carlo (MC) algorithm is developed for the numerical simulation of aerosol dynamics, that is, nucleation, surface growth, and coagulation. Nucleation and surface growth are handled with deterministic means, while coagulation is simulated with a stochastic method (Marcus-Lushnikov stochastic process). Operator splitting techniques are used to synthesize the deterministic and stochastic parts in the algorithm. The algorithm is parallelized using the Message Passing Interface (MPI). The parallel computing efficiency is investigated through numerical examples. Near 60% parallel efficiency is achieved for the maximum testing case with 3.7 million MC particles running on 93 parallel computing nodes. The algorithm is verified through simulating various testing cases and comparing the simulation results with available analytical and/or other numerical solutions. Generally, it is found that only small number (hundreds or thousands) of MC particles is necessary to accurately predict the aerosol particle number density, volume fraction, and so forth, that is, low order moments of the Particle Size Distribution (PSD) function. Accurately predicting the high order moments of the PSD needs to dramatically increase the number of MC particles. 2014 Kun Zhou et al.

  12. Monte Carlo Simulation of River Meander Modelling

    Science.gov (United States)

    Posner, A. J.; Duan, J. G.

    2010-12-01

    This study first compares the first order analytical solutions for flow field by Ikeda et. al. (1981) and Johanesson and Parker (1989b). Ikeda et. al.’s (1981) linear bank erosion model was implemented to predict the rate of bank erosion in which the bank erosion coefficient is treated as a stochastic variable that varies with physical properties of the bank (e.g. cohesiveness, stratigraphy, vegetation density). The developed model was used to predict the evolution of meandering planforms. Then, the modeling results were analyzed and compared to the observed data. Since the migration of meandering channel consists of downstream translation, lateral expansion, and downstream or upstream rotations. Several measures are formulated in order to determine which of the resulting planform is closest to the experimental measured one. Results from the deterministic model highly depend on the calibrated erosion coefficient. Since field measurements are always limited, the stochastic model yielded more realistic predictions of meandering planform evolutions. Due to the random nature of bank erosion coefficient, the meandering planform evolution is a stochastic process that can only be accurately predicted by a stochastic model. Quasi-2D Ikeda (1989) flow solution with Monte Carlo Simulation of Bank Erosion Coefficient.

  13. Monte Carlo Simulations of the Photospheric Process

    CERN Document Server

    Santana, Rodolfo; Hernandez, Roberto A; Kumar, Pawan

    2015-01-01

    We present a Monte Carlo (MC) code we wrote to simulate the photospheric process and to study the photospheric spectrum above the peak energy. Our simulations were performed with a photon to electron ratio $N_{\\gamma}/N_{e} = 10^{5}$, as determined by observations of the GRB prompt emission. We searched an exhaustive parameter space to determine if the photospheric process can match the observed high-energy spectrum of the prompt emission. If we do not consider electron re-heating, we determined that the best conditions to produce the observed high-energy spectrum are low photon temperatures and high optical depths. However, for these simulations, the spectrum peaks at an energy below 300 keV by a factor $\\sim 10$. For the cases we consider with higher photon temperatures and lower optical depths, we demonstrate that additional energy in the electrons is required to produce a power-law spectrum above the peak-energy. By considering electron re-heating near the photosphere, the spectrum for these simulations h...

  14. Finding Planet Nine: a Monte Carlo approach

    CERN Document Server

    Marcos, C de la Fuente

    2016-01-01

    Planet Nine is a hypothetical planet located well beyond Pluto that has been proposed in an attempt to explain the observed clustering in physical space of the perihelia of six extreme trans-Neptunian objects or ETNOs. The predicted approximate values of its orbital elements include a semimajor axis of 700 au, an eccentricity of 0.6, an inclination of 30 degrees, and an argument of perihelion of 150 degrees. Searching for this putative planet is already under way. Here, we use a Monte Carlo approach to create a synthetic population of Planet Nine orbits and study its visibility statistically in terms of various parameters and focusing on the aphelion configuration. Our analysis shows that, if Planet Nine exists and is at aphelion, it might be found projected against one out of four specific areas in the sky. Each area is linked to a particular value of the longitude of the ascending node and two of them are compatible with an apsidal antialignment scenario. In addition and after studying the current statistic...

  15. Parallel Monte Carlo Simulation of Aerosol Dynamics

    Directory of Open Access Journals (Sweden)

    Kun Zhou

    2014-02-01

    Full Text Available A highly efficient Monte Carlo (MC algorithm is developed for the numerical simulation of aerosol dynamics, that is, nucleation, surface growth, and coagulation. Nucleation and surface growth are handled with deterministic means, while coagulation is simulated with a stochastic method (Marcus-Lushnikov stochastic process. Operator splitting techniques are used to synthesize the deterministic and stochastic parts in the algorithm. The algorithm is parallelized using the Message Passing Interface (MPI. The parallel computing efficiency is investigated through numerical examples. Near 60% parallel efficiency is achieved for the maximum testing case with 3.7 million MC particles running on 93 parallel computing nodes. The algorithm is verified through simulating various testing cases and comparing the simulation results with available analytical and/or other numerical solutions. Generally, it is found that only small number (hundreds or thousands of MC particles is necessary to accurately predict the aerosol particle number density, volume fraction, and so forth, that is, low order moments of the Particle Size Distribution (PSD function. Accurately predicting the high order moments of the PSD needs to dramatically increase the number of MC particles.

  16. Measuring Berry curvature with quantum Monte Carlo

    CERN Document Server

    Kolodrubetz, Michael

    2014-01-01

    The Berry curvature and its descendant, the Berry phase, play an important role in quantum mechanics. They can be used to understand the Aharonov-Bohm effect, define topological Chern numbers, and generally to investigate the geometric properties of a quantum ground state manifold. While Berry curvature has been well-studied in the regimes of few-body physics and non-interacting particles, its use in the regime of strong interactions is hindered by the lack of numerical methods to solve it. In this paper we fill this gap by implementing a quantum Monte Carlo method to solve for the Berry curvature, based on interpreting Berry curvature as a leading correction to imaginary time ramps. We demonstrate our algorithm using the transverse-field Ising model in one and two dimensions, the latter of which is non-integrable. Despite the fact that the Berry curvature gives information about the phase of the wave function, we show that our algorithm has no sign or phase problem for standard sign-problem-free Hamiltonians...

  17. Atomistic Monte Carlo Simulation of Lipid Membranes

    Directory of Open Access Journals (Sweden)

    Daniel Wüstner

    2014-01-01

    Full Text Available Biological membranes are complex assemblies of many different molecules of which analysis demands a variety of experimental and computational approaches. In this article, we explain challenges and advantages of atomistic Monte Carlo (MC simulation of lipid membranes. We provide an introduction into the various move sets that are implemented in current MC methods for efficient conformational sampling of lipids and other molecules. In the second part, we demonstrate for a concrete example, how an atomistic local-move set can be implemented for MC simulations of phospholipid monomers and bilayer patches. We use our recently devised chain breakage/closure (CBC local move set in the bond-/torsion angle space with the constant-bond-length approximation (CBLA for the phospholipid dipalmitoylphosphatidylcholine (DPPC. We demonstrate rapid conformational equilibration for a single DPPC molecule, as assessed by calculation of molecular energies and entropies. We also show transition from a crystalline-like to a fluid DPPC bilayer by the CBC local-move MC method, as indicated by the electron density profile, head group orientation, area per lipid, and whole-lipid displacements. We discuss the potential of local-move MC methods in combination with molecular dynamics simulations, for example, for studying multi-component lipid membranes containing cholesterol.

  18. Intervención humana y transformación de los paisajes forestales en la cuenca del Duero durante la edad moderna

    Directory of Open Access Journals (Sweden)

    José María Ramos Santos

    2005-01-01

    Full Text Available La actuación humana ejercida sobre los montes durante la Edad Moderna constituye un claro exponente de la posición central que ocupaban los montes en el espacio agrario, no sólo pinares, sino también encinares y quejigares, responden a este interés humano por el monte. De esta manera se manifi esta cómo el conjunto de los montes adquiere su verdadera fi sonomía a través de esta actuación humana, sostenida en el tiempo a través de auténticos programas plasmados en las Ordenanzas Montes y en las Ordenanzas Municipales. Esta intervención adquiere distintas características en función de los intereses de cada comunidad rural y en relación con distintos momentos históricos. De esta manera junto a algunas constantes vinculadas con la intervención en los montes pueden señalarse grandes diferencias, pues mientras en unas zonas el monte se reduce en favor de las tierras cultivadas, en otras se conserva y se amplia. Estas diferencias, así pues, constituyen un efecto del prestigio del monte o de su olvido como soporte o equilibrio de la actividad rural.

  19. LA POLITICA SOCIAL DEL "GOBIERNO DEL CAMBIO"

    OpenAIRE

    Laura Mota Díaz

    2002-01-01

    El artículo se centra en la política social del actual sexenio foxista , la cual se ha definido como incluyente y equitativa dentro del marco de un gobierno autodenominado del cambio, no sólo por lo que se refiere a la alternancia política del poder, sino porque además pretende ser un gobierno con una visión más amplia del desarrollo. Todo ello se traduce en nuevas estrategias para alcanzar la democracia, la equidad, la justicia social y el bienestar general de la población. El ob...

  20. Micromamíferos del Pleistoceno Superior del yacimiento de PRERESA en el valle del Manzanares y su contribución a la reconstrucción paleoambiental de la cuenca de Madrid durante el Pleistoceno

    Directory of Open Access Journals (Sweden)

    Sesé, C.

    2011-12-01

    ubica el yacimiento, excepto Cricetulus (Allocricetus bursae que se extinguió en la Península Ibérica al final del Pleistoceno Superior. Las observaciones realizadas sobre el material indican que la acumulación de restos de micromamíferos en el yacimiento es debida, en su mayor parte, a la acción de predadores, muy posiblemente a egagrópilas de aves rapaces. La asociación de micromamíferos de PRERESA indica unas condiciones de clima templado con cierta humedad y un desarrollo de la vegetación con algunas zonas boscosas y fundamentalmente áreas abiertas pero con vegetación arbustiva, herbácea, praderas secas y húmedas, y ribereña. En una comparación de los micromamíferos del yacimiento de PRERESA con los de los yacimientos del Pleistoceno Medio de Áridos 1 y Valdocarros, los datos indican que en los tramos bajos de los ríos Manzanares y Jarama hubo unas condiciones climáticas y paisajísticas similares en los momentos que representan estos yacimientos (Pleistoceno Medio avanzado y primer tercio del Pleistoceno Superior. Sin embargo, y al igual que sucede en la actualidad, estas condiciones fueron algo diferentes en el valle del Lozoya en la Sierra de Guadarrama durante el primer tercio del Pleistoceno Superior, según indica la asociación de micromamíferos de la Cueva del Camino (Pinilla del Valle, Madrid, que sugiere un clima relativamente más húmedo y un medio con una mayor variedad de biotopos. La asociación de micromamíferos del Pleistoceno Superior de PRERESA, en el tramo bajo del Manzanares, comparada con la de la Cueva del Camino que tiene una cronología similar, y con otras del Norte de Madrid del Pleistoceno Superior, pone de manifiesto según nuestras observaciones una diferenciación biogeográfica y paleoclimática ya durante este periodo entre unas y otras, de las que la zona limitante serían más o menos las estribaciones meridionales y centro-orientales del Sistema Central.

  1. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1985

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1985 calendar year. The report begins with a summary...

  2. An Introduction to Multilevel Monte Carlo for Option Valuation

    CERN Document Server

    Higham, Desmond J

    2015-01-01

    Monte Carlo is a simple and flexible tool that is widely used in computational finance. In this context, it is common for the quantity of interest to be the expected value of a random variable defined via a stochastic differential equation. In 2008, Giles proposed a remarkable improvement to the approach of discretizing with a numerical method and applying standard Monte Carlo. His multilevel Monte Carlo method offers an order of speed up given by the inverse of epsilon, where epsilon is the required accuracy. So computations can run 100 times more quickly when two digits of accuracy are required. The multilevel philosophy has since been adopted by a range of researchers and a wealth of practically significant results has arisen, most of which have yet to make their way into the expository literature. In this work, we give a brief, accessible, introduction to multilevel Monte Carlo and summarize recent results applicable to the task of option evaluation.

  3. Using Supervised Learning to Improve Monte Carlo Integral Estimation

    CERN Document Server

    Tracey, Brendan; Alonso, Juan J

    2011-01-01

    Monte Carlo (MC) techniques are often used to estimate integrals of a multivariate function using randomly generated samples of the function. In light of the increasing interest in uncertainty quantification and robust design applications in aerospace engineering, the calculation of expected values of such functions (e.g. performance measures) becomes important. However, MC techniques often suffer from high variance and slow convergence as the number of samples increases. In this paper we present Stacked Monte Carlo (StackMC), a new method for post-processing an existing set of MC samples to improve the associated integral estimate. StackMC is based on the supervised learning techniques of fitting functions and cross validation. It should reduce the variance of any type of Monte Carlo integral estimate (simple sampling, importance sampling, quasi-Monte Carlo, MCMC, etc.) without adding bias. We report on an extensive set of experiments confirming that the StackMC estimate of an integral is more accurate than ...

  4. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1987 calendar year. The report begins with a summary...

  5. The Trail Inventory of Monte Vista NWR [Cycle 3

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The purpose of this report is to create a baseline inventory of all non-motorized trails on Monte Vista National Wildlife Refuge. Trails in this inventory are...

  6. Monte Vista and Alamosa NWR Water Use Report- 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes water use at Monte Vista and Alamosa NWR for 1983. The document includes summaries of 1983 water use, 1984 water program recommendations, and...

  7. Monte Vista and Alamosa NWR Water Use Report- 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes water use at Monte Vista and Alamosa NWR for 1986. The document includes summaries of 1986 water use, 1987 water program recommendations, and...

  8. Monte Vista and Alamosa NWR Water Use Report- 1987

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes water use at Monte Vista and Alamosa NWR for 1987. The document includes summaries of 1987 water use, 1988 water program recommendations, and...

  9. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1979

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1979 calendar year. The report begins with an introduction...

  10. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1984 calendar year. The report begins with a summary...

  11. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1970

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1970 calendar year. The report begins by summarizing...

  12. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1980

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1980 calendar year. The report begins with an introduction...

  13. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1977

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1977 calendar year. The report begins with an introduction...

  14. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1972

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1972 calendar year. The report begins by summarizing...

  15. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1978

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1978 calendar year. The report begins with an introduction...

  16. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1969

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1969 calendar year. The report begins by summarizing...

  17. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1981

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1981 calendar year. The report begins with a summary...

  18. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1982

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1982 calendar year. The report begins with a summary...

  19. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1976

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1976 calendar year. The report begins with an introduction...

  20. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1971

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1971 calendar year. The report begins by summarizing...

  1. Monte Vista National Wildlife Refuge : Narrative Report : Fiscal Year 1974

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the fiscal year 1974. The report begins by summarizing...

  2. Monte Vista National Wildlife Refuge : Narrative Report : Fiscal Year 1975

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the fiscal year 1975. The report begins by summarizing...

  3. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1988 calendar year. The report begins with a summary...

  4. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1994 calendar year. The report begins with a summary...

  5. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1991

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1991 calendar year. The report begins with a summary...

  6. MODELING LEACHING OF VIRUSES BY THE MONTE CARLO METHOD

    Science.gov (United States)

    A predictive screening model was developed for fate and transport of viruses in the unsaturated zone. A database of input parameters allowed Monte Carlo analysis with the model. The resulting kernel densities of predicted attenuation during percolation indicated very ...

  7. A MONTE-CARLO METHOD FOR ESTIMATING THE CORRELATION EXPONENT

    NARCIS (Netherlands)

    MIKOSCH, T; WANG, QA

    1995-01-01

    We propose a Monte Carlo method for estimating the correlation exponent of a stationary ergodic sequence. The estimator can be considered as a bootstrap version of the classical Hill estimator. A simulation study shows that the method yields reasonable estimates.

  8. Bayesian phylogeny analysis via stochastic approximation Monte Carlo

    KAUST Repository

    Cheon, Sooyoung

    2009-11-01

    Monte Carlo methods have received much attention in the recent literature of phylogeny analysis. However, the conventional Markov chain Monte Carlo algorithms, such as the Metropolis-Hastings algorithm, tend to get trapped in a local mode in simulating from the posterior distribution of phylogenetic trees, rendering the inference ineffective. In this paper, we apply an advanced Monte Carlo algorithm, the stochastic approximation Monte Carlo algorithm, to Bayesian phylogeny analysis. Our method is compared with two popular Bayesian phylogeny software, BAMBE and MrBayes, on simulated and real datasets. The numerical results indicate that our method outperforms BAMBE and MrBayes. Among the three methods, SAMC produces the consensus trees which have the highest similarity to the true trees, and the model parameter estimates which have the smallest mean square errors, but costs the least CPU time. © 2009 Elsevier Inc. All rights reserved.

  9. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1992 calendar year. The report begins with a summary...

  10. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1986 calendar year. The report begins with a summary...

  11. Bayesian phylogeny analysis via stochastic approximation Monte Carlo.

    Science.gov (United States)

    Cheon, Sooyoung; Liang, Faming

    2009-11-01

    Monte Carlo methods have received much attention in the recent literature of phylogeny analysis. However, the conventional Markov chain Monte Carlo algorithms, such as the Metropolis-Hastings algorithm, tend to get trapped in a local mode in simulating from the posterior distribution of phylogenetic trees, rendering the inference ineffective. In this paper, we apply an advanced Monte Carlo algorithm, the stochastic approximation Monte Carlo algorithm, to Bayesian phylogeny analysis. Our method is compared with two popular Bayesian phylogeny software, BAMBE and MrBayes, on simulated and real datasets. The numerical results indicate that our method outperforms BAMBE and MrBayes. Among the three methods, SAMC produces the consensus trees which have the highest similarity to the true trees, and the model parameter estimates which have the smallest mean square errors, but costs the least CPU time.

  12. Monte Carlo techniques for analyzing deep penetration problems

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, S.N.; Gonnord, J.; Hendricks, J.S.

    1985-01-01

    A review of current methods and difficulties in Monte Carlo deep-penetration calculations is presented. Statistical uncertainty is discussed, and recent adjoint optimization of splitting, Russian roulette, and exponential transformation biasing is reviewed. Other aspects of the random walk and estimation processes are covered, including the relatively new DXANG angular biasing technique. Specific items summarized are albedo scattering, Monte Carlo coupling techniques with discrete ordinates and other methods, adjoint solutions, and multi-group Monte Carlo. The topic of code-generated biasing parameters is presented, including the creation of adjoint importance functions from forward calculations. Finally, current and future work in the area of computer learning and artificial intelligence is discussed in connection with Monte Carlo applications. 29 refs.

  13. EXTENDED MONTE CARLO LOCALIZATION ALGORITHM FOR MOBILE SENSOR NETWORKS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A real-world localization system for wireless sensor networks that adapts for mobility and irregular radio propagation model is considered.The traditional range-based techniques and recent range-free localization schemes are not welt competent for localization in mobile sensor networks,while the probabilistic approach of Bayesian filtering with particle-based density representations provides a comprehensive solution to such localization problem.Monte Carlo localization is a Bayesian filtering method that approximates the mobile node’S location by a set of weighted particles.In this paper,an enhanced Monte Carlo localization algorithm-Extended Monte Carlo Localization (Ext-MCL) is suitable for the practical wireless network environment where the radio propagation model is irregular.Simulation results show the proposal gets better localization accuracy and higher localizable node number than previously proposed Monte Carlo localization schemes not only for ideal radio model,but also for irregular one.

  14. 1993 farming and grazing program plans for Monte Vista NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Plans for farming and grazing at Monte Vista National Wildlife Refuge for 1993. This program will use rotations of small grain, field peas, and legumes as a farming...

  15. [Monte Vista National Wildlife Refuge livestock grazing lawsuit : Information packet

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Packet of information from the Colorado Cattlemen's Association concerning the 1992 lawsuit filed against the Monte Vista National Wildlife Refuge. The suit was...

  16. Trip report : Alamosa and Monte Vista National Wildlife Refuges

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report is a summary a trip to Alamosa National Wildlife Refuge and Monte Vista National Wildlife Refuge in 1991, and focuses on the hydrology and soil habitat...

  17. Monte Vista and Alamosa NWR Water Use Report- 1980

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes water use at Monte Vista and Alamosa NWR for 1980. The document includes summaries of 1980 water use, 1981 water program recommendations, and...

  18. Monte Carlo simulations: Hidden errors from ``good'' random number generators

    Science.gov (United States)

    Ferrenberg, Alan M.; Landau, D. P.; Wong, Y. Joanna

    1992-12-01

    The Wolff algorithm is now accepted as the best cluster-flipping Monte Carlo algorithm for beating ``critical slowing down.'' We show how this method can yield incorrect answers due to subtle correlations in ``high quality'' random number generators.

  19. Anu Välba ronib Mont Blanci tippu

    Index Scriptorium Estoniae

    2008-01-01

    Teleajakirjanik esindab Eesti naisi Euroliidu liikmesmaade naiste ühisretkel, millega tähistatakse Prantsusmaa EL eesistumisaja algust ja 200 aasta möödumist esimese naise jõudmisest Mont Blanci tippu

  20. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1967

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1967 calendar year. The report begins by summarizing...

  1. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1968

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1968 calendar year. The report begins by summarizing...

  2. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1989 calendar year. The report begins with a summary...

  3. On the Markov Chain Monte Carlo (MCMC) method

    Indian Academy of Sciences (India)

    Rajeeva L Karandikar

    2006-04-01

    Markov Chain Monte Carlo (MCMC) is a popular method used to generate samples from arbitrary distributions, which may be specified indirectly. In this article, we give an introduction to this method along with some examples.

  4. Monte-Carlo simulation-based statistical modeling

    CERN Document Server

    Chen, John

    2017-01-01

    This book brings together expert researchers engaged in Monte-Carlo simulation-based statistical modeling, offering them a forum to present and discuss recent issues in methodological development as well as public health applications. It is divided into three parts, with the first providing an overview of Monte-Carlo techniques, the second focusing on missing data Monte-Carlo methods, and the third addressing Bayesian and general statistical modeling using Monte-Carlo simulations. The data and computer programs used here will also be made publicly available, allowing readers to replicate the model development and data analysis presented in each chapter, and to readily apply them in their own research. Featuring highly topical content, the book has the potential to impact model development and data analyses across a wide spectrum of fields, and to spark further research in this direction.

  5. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1983

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1983 calendar year. The report begins with a summary...

  6. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1993 calendar year. The report begins with a summary...

  7. Monte Vista National Wildlife Refuge : Narrative Report : Calendar Year 1990

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Monte Vista National Wildlife Refuge outlines Refuge accomplishments during the 1990 calendar year. The report begins with a summary...

  8. Accelerating Monte Carlo Renderers by Ray Histogram Fusion

    Directory of Open Access Journals (Sweden)

    Mauricio Delbracio

    2015-03-01

    Full Text Available This paper details the recently introduced Ray Histogram Fusion (RHF filter for accelerating Monte Carlo renderers [M. Delbracio et al., Boosting Monte Carlo Rendering by Ray Histogram Fusion, ACM Transactions on Graphics, 33 (2014]. In this filter, each pixel in the image is characterized by the colors of the rays that reach its surface. Pixels are compared using a statistical distance on the associated ray color distributions. Based on this distance, it decides whether two pixels can share their rays or not. The RHF filter is consistent: as the number of samples increases, more evidence is required to average two pixels. The algorithm provides a significant gain in PSNR, or equivalently accelerates the rendering process by using many fewer Monte Carlo samples without observable bias. Since the RHF filter depends only on the Monte Carlo samples color values, it can be naturally combined with all rendering effects.

  9. Monte Vista and Alamosa NWR Water Use Report- 1984

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes water use at Monte Vista and Alamosa NWR for 1984. The document includes summaries of 1984 water use, 1985 water program recommendations, and...

  10. Monte Carlo methods for light propagation in biological tissues

    OpenAIRE

    Vinckenbosch, Laura; Lacaux, Céline; Tindel, Samy; Thomassin, Magalie; Obara, Tiphaine

    2016-01-01

    Light propagation in turbid media is driven by the equation of radiative transfer. We give a formal probabilistic representation of its solution in the framework of biological tissues and we implement algorithms based on Monte Carlo methods in order to estimate the quantity of light that is received by a homogeneous tissue when emitted by an optic fiber. A variance reduction method is studied and implemented, as well as a Markov chain Monte Carlo method based on the Metropolis–Hastings algori...

  11. de Finetti Priors using Markov chain Monte Carlo computations.

    Science.gov (United States)

    Bacallado, Sergio; Diaconis, Persi; Holmes, Susan

    2015-07-01

    Recent advances in Monte Carlo methods allow us to revisit work by de Finetti who suggested the use of approximate exchangeability in the analyses of contingency tables. This paper gives examples of computational implementations using Metropolis Hastings, Langevin and Hamiltonian Monte Carlo to compute posterior distributions for test statistics relevant for testing independence, reversible or three way models for discrete exponential families using polynomial priors and Gröbner bases.

  12. Study of the Transition Flow Regime using Monte Carlo Methods

    Science.gov (United States)

    Hassan, H. A.

    1999-01-01

    This NASA Cooperative Agreement presents a study of the Transition Flow Regime Using Monte Carlo Methods. The topics included in this final report are: 1) New Direct Simulation Monte Carlo (DSMC) procedures; 2) The DS3W and DS2A Programs; 3) Papers presented; 4) Miscellaneous Applications and Program Modifications; 5) Solution of Transitional Wake Flows at Mach 10; and 6) Turbulence Modeling of Shock-Dominated Fows with a k-Enstrophy Formulation.

  13. Monte Carlo Simulation of Optical Properties of Wake Bubbles

    Institute of Scientific and Technical Information of China (English)

    CAO Jing; WANG Jiang-An; JIANG Xing-Zhou; SHI Sheng-Wei

    2007-01-01

    Based on Mie scattering theory and the theory of multiple light scattering, the light scattering properties of air bubbles in a wake are analysed by Monte Carlo simulation. The results show that backscattering is enhanced obviously due to the existence of bubbles, especially with the increase of bubble density, and that it is feasible to use the Monte Carlo method to study the properties of light scattering by air bubbles.

  14. A Note for Monte-Carlo Finite Difference Method and Monte-Carlo Finite Element Method%Monte-Carlo有限差分法和Monte-Carlo有限元法的一点注记

    Institute of Scientific and Technical Information of China (English)

    唐立; 朱起定; 杨文胜

    2003-01-01

    本文以二维调和方程第一边值问题为例,探讨了Monte-Carlo有限差分法和Monte-Carlo有限元法的概率实质,将差分法和有限元法的数值解表示成了统一的随机表达式,显示了有限差分法和有限元法共同的本质.

  15. Successful combination of the stochastic linearization and Monte Carlo methods

    Science.gov (United States)

    Elishakoff, I.; Colombi, P.

    1993-01-01

    A combination of a stochastic linearization and Monte Carlo techniques is presented for the first time in literature. A system with separable nonlinear damping and nonlinear restoring force is considered. The proposed combination of the energy-wise linearization with the Monte Carlo method yields an error under 5 percent, which corresponds to the error reduction associated with the conventional stochastic linearization by a factor of 4.6.

  16. Confidence and efficiency scaling in variational quantum Monte Carlo calculations

    Science.gov (United States)

    Delyon, F.; Bernu, B.; Holzmann, Markus

    2017-02-01

    Based on the central limit theorem, we discuss the problem of evaluation of the statistical error of Monte Carlo calculations using a time-discretized diffusion process. We present a robust and practical method to determine the effective variance of general observables and show how to verify the equilibrium hypothesis by the Kolmogorov-Smirnov test. We then derive scaling laws of the efficiency illustrated by variational Monte Carlo calculations on the two-dimensional electron gas.

  17. Confidence and efficiency scaling in Variational Quantum Monte Carlo calculations

    CERN Document Server

    Delyon, François; Holzmann, Markus

    2016-01-01

    Based on the central limit theorem, we discuss the problem of evaluation of the statistical error of Monte Carlo calculations using a time discretized diffusion process. We present a robust and practical method to determine the effective variance of general observables and show how to verify the equilibrium hypothesis by the Kolmogorov-Smirnov test. We then derive scaling laws of the efficiency illustrated by Variational Monte Carlo calculations on the two dimensional electron gas.

  18. Geometrical and Monte Carlo projectors in 3D PET reconstruction

    OpenAIRE

    Aguiar, Pablo; Rafecas López, Magdalena; Ortuno, Juan Enrique; Kontaxakis, George; Santos, Andrés; Pavía, Javier; Ros, Domènec

    2010-01-01

    Purpose: In the present work, the authors compare geometrical and Monte Carlo projectors in detail. The geometrical projectors considered were the conventional geometrical Siddon ray-tracer (S-RT) and the orthogonal distance-based ray-tracer (OD-RT), based on computing the orthogonal distance from the center of image voxel to the line-of-response. A comparison of these geometrical projectors was performed using different point spread function (PSF) models. The Monte Carlo-based method under c...

  19. Radiative Equilibrium and Temperature Correction in Monte Carlo Radiation Transfer

    OpenAIRE

    Bjorkman, J. E.; Wood, Kenneth

    2001-01-01

    We describe a general radiative equilibrium and temperature correction procedure for use in Monte Carlo radiation transfer codes with sources of temperature-independent opacity, such as astrophysical dust. The technique utilizes the fact that Monte Carlo simulations track individual photon packets, so we may easily determine where their energy is absorbed. When a packet is absorbed, it heats a particular cell within the envelope, raising its temperature. To enforce radiative equilibrium, the ...

  20. Chemical accuracy from quantum Monte Carlo for the Benzene Dimer

    OpenAIRE

    Azadi, Sam; Cohen, R. E

    2015-01-01

    We report an accurate study of interactions between Benzene molecules using variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) methods. We compare these results with density functional theory (DFT) using different van der Waals (vdW) functionals. In our QMC calculations, we use accurate correlated trial wave functions including three-body Jastrow factors, and backflow transformations. We consider two benzene molecules in the parallel displaced (PD) geometry, and fin...

  1. Event-chain Monte Carlo for classical continuous spin models

    Science.gov (United States)

    Michel, Manon; Mayer, Johannes; Krauth, Werner

    2015-10-01

    We apply the event-chain Monte Carlo algorithm to classical continuum spin models on a lattice and clarify the condition for its validity. In the two-dimensional XY model, it outperforms the local Monte Carlo algorithm by two orders of magnitude, although it remains slower than the Wolff cluster algorithm. In the three-dimensional XY spin glass model at low temperature, the event-chain algorithm is far superior to the other algorithms.

  2. Public Infrastructure for Monte Carlo Simulation: publicMC@BATAN

    CERN Document Server

    Waskita, A A; Akbar, Z; Handoko, L T; 10.1063/1.3462759

    2010-01-01

    The first cluster-based public computing for Monte Carlo simulation in Indonesia is introduced. The system has been developed to enable public to perform Monte Carlo simulation on a parallel computer through an integrated and user friendly dynamic web interface. The beta version, so called publicMC@BATAN, has been released and implemented for internal users at the National Nuclear Energy Agency (BATAN). In this paper the concept and architecture of publicMC@BATAN are presented.

  3. Monte Carlo methods and applications in nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, J.

    1990-01-01

    Monte Carlo methods for studying few- and many-body quantum systems are introduced, with special emphasis given to their applications in nuclear physics. Variational and Green's function Monte Carlo methods are presented in some detail. The status of calculations of light nuclei is reviewed, including discussions of the three-nucleon-interaction, charge and magnetic form factors, the coulomb sum rule, and studies of low-energy radiative transitions. 58 refs., 12 figs.

  4. Monte Carlo method for solving a parabolic problem

    Directory of Open Access Journals (Sweden)

    Tian Yi

    2016-01-01

    Full Text Available In this paper, we present a numerical method based on random sampling for a parabolic problem. This method combines use of the Crank-Nicolson method and Monte Carlo method. In the numerical algorithm, we first discretize governing equations by Crank-Nicolson method, and obtain a large sparse system of linear algebraic equations, then use Monte Carlo method to solve the linear algebraic equations. To illustrate the usefulness of this technique, we apply it to some test problems.

  5. del discurso

    Directory of Open Access Journals (Sweden)

    Alexander Mosquera

    2006-01-01

    Full Text Available En varios comunicados quedó reflejada la tensión de la reciente crisis entre Colombia y Venezuela, suscitada a raíz de la captura en diciembre de 2004 de un guerrillero de la FARC en Caracas (Rodrigo Granda. El presente trabajo es un avance de un proyecto de investigación, que persigue como objetivos: 1 describir el discurso implícito en dichos comunicados; 2 identificar los aspectos semánticos y pragmáticos presentes en la confrontación discursiva; y 3 delinear el componente ideológico reflejado en los comunicados. Para el respectivo análisis se siguieron algunos aspectos teóricos y metodológicos de Colle (2000, Bolívar (1998 yMolero de Cabeza (1985. Entre las conclusiones preliminares de este avance se tiene que, con el caso Granda, Colombia recurrió a la vieja política del "fin justifica los medios", a la vez que puso en entredicho el papel de Venezuela en la lucha contra el terrorismo, quizás como respuesta a su política exterior de estrechos vínculos con el gobierno estadounidense

  6. Implications of Monte Carlo Statistical Errors in Criticality Safety Assessments

    Energy Technology Data Exchange (ETDEWEB)

    Pevey, Ronald E.

    2005-09-15

    Most criticality safety calculations are performed using Monte Carlo techniques because of Monte Carlo's ability to handle complex three-dimensional geometries. For Monte Carlo calculations, the more histories sampled, the lower the standard deviation of the resulting estimates. The common intuition is, therefore, that the more histories, the better; as a result, analysts tend to run Monte Carlo analyses as long as possible (or at least to a minimum acceptable uncertainty). For Monte Carlo criticality safety analyses, however, the optimization situation is complicated by the fact that procedures usually require that an extra margin of safety be added because of the statistical uncertainty of the Monte Carlo calculations. This additional safety margin affects the impact of the choice of the calculational standard deviation, both on production and on safety. This paper shows that, under the assumptions of normally distributed benchmarking calculational errors and exact compliance with the upper subcritical limit (USL), the standard deviation that optimizes production is zero, but there is a non-zero value of the calculational standard deviation that minimizes the risk of inadvertently labeling a supercritical configuration as subcritical. Furthermore, this value is shown to be a simple function of the typical benchmarking step outcomes--the bias, the standard deviation of the bias, the upper subcritical limit, and the number of standard deviations added to calculated k-effectives before comparison to the USL.

  7. A Survey on Multilevel Monte Carlo for European Options

    Directory of Open Access Journals (Sweden)

    Masoud Moharamnejad

    2016-03-01

    Full Text Available One of the most applicable and common methods for pricing options is the Monte Carlo simulation. Among the advantages of this method we can name ease of use, being suitable for different types of options including vanilla options and exotic options. On one hand, convergence rate of Monte Carlo's variance is , which has a slow convergence in responding problems, such that for achieving accuracy of ε for a d dimensional problem, computation complexity would be . Thus, various methods have been proposed in Monte Carlo framework to increase the convergence rate of variance as variance reduction methods. One of the recent methods was proposed by Gills in 2006, is the multilevel Monte Carlo method. This method besides reducing the computationcomplexity to while being used in Euler discretizing and to while being used in Milsteindiscretizing method, has the capacity to be combined with other variance reduction methods. In this article, multilevel Monte Carlo using Euler and Milsteindiscretizing methods is adopted for comparing computation complexity with standard Monte Carlo method in pricing European call options.

  8. Perturbation Monte Carlo methods for tissue structure alterations.

    Science.gov (United States)

    Nguyen, Jennifer; Hayakawa, Carole K; Mourant, Judith R; Spanier, Jerome

    2013-01-01

    This paper describes an extension of the perturbation Monte Carlo method to model light transport when the phase function is arbitrarily perturbed. Current perturbation Monte Carlo methods allow perturbation of both the scattering and absorption coefficients, however, the phase function can not be varied. The more complex method we develop and test here is not limited in this way. We derive a rigorous perturbation Monte Carlo extension that can be applied to a large family of important biomedical light transport problems and demonstrate its greater computational efficiency compared with using conventional Monte Carlo simulations to produce forward transport problem solutions. The gains of the perturbation method occur because only a single baseline Monte Carlo simulation is needed to obtain forward solutions to other closely related problems whose input is described by perturbing one or more parameters from the input of the baseline problem. The new perturbation Monte Carlo methods are tested using tissue light scattering parameters relevant to epithelia where many tumors originate. The tissue model has parameters for the number density and average size of three classes of scatterers; whole nuclei, organelles such as lysosomes and mitochondria, and small particles such as ribosomes or large protein complexes. When these parameters or the wavelength is varied the scattering coefficient and the phase function vary. Perturbation calculations give accurate results over variations of ∼15-25% of the scattering parameters.

  9. Mont-Tremblant biodiesel project : feasibility study; Projet biodiesel Mont-Tremblant : etude de faisabilite

    Energy Technology Data Exchange (ETDEWEB)

    Lagace, C. [Groupe Sine Nomine, Montreal, PQ (Canada); Lamy, V.; Lapointe, L.; Pilon, B. [CEGEP de Saint-Jerome, Saint-Jerome, PQ (Canada). Inst. du transport avance du Quebec, ITAQ

    2008-08-15

    The growing interest in biodiesel can be attributed to concerns regarding climate change, environmental protection and sustainable development. Biodiesel produced from biomass is a renewable energy source that can replace fossil fuels and help reduce greenhouse gas emissions. The City of Mont-Tremblant commissioned a pilot study to determine the feasibility of integrating 20 per cent biodiesel (B20) in city fleet vehicles and school buses. The study focused on the use of biodiesel fuel under winter conditions. The fleet vehicles were analyzed and various strategies for integrating biodiesel mixtures by type and concentration were proposed. The feasibility study also investigated different types of petrodiesel such as Nordic type, seasonal type and kerosene. The effects of an electrical thermal management system were also investigated along with the use of additives. Various laboratory tests were performed in a controlled climate chamber to validate potential solutions. Finally, the study measured the impacts of likely solutions, and proposed 4 different scenarios for the use of biodiesel for the region of Mont-Tremblant. The study showed that it is possible to use B20 year-round, provided that certain conditions are met. The pilot project will also evaluate changes to storage infrastructure that may be needed for storing B20 in winter. 5 tabs., 10 figs., 2 appendices.

  10. Monte Carlo Volcano Seismic Moment Tensors

    Science.gov (United States)

    Waite, G. P.; Brill, K. A.; Lanza, F.

    2015-12-01

    Inverse modeling of volcano seismic sources can provide insight into the geometry and dynamics of volcanic conduits. But given the logistical challenges of working on an active volcano, seismic networks are typically deficient in spatial and temporal coverage; this potentially leads to large errors in source models. In addition, uncertainties in the centroid location and moment-tensor components, including volumetric components, are difficult to constrain from the linear inversion results, which leads to a poor understanding of the model space. In this study, we employ a nonlinear inversion using a Monte Carlo scheme with the objective of defining robustly resolved elements of model space. The model space is randomized by centroid location and moment tensor eigenvectors. Point sources densely sample the summit area and moment tensors are constrained to a randomly chosen geometry within the inversion; Green's functions for the random moment tensors are all calculated from modeled single forces, making the nonlinear inversion computationally reasonable. We apply this method to very-long-period (VLP) seismic events that accompany minor eruptions at Fuego volcano, Guatemala. The library of single force Green's functions is computed with a 3D finite-difference modeling algorithm through a homogeneous velocity-density model that includes topography, for a 3D grid of nodes, spaced 40 m apart, within the summit region. The homogenous velocity and density model is justified by long wavelength of VLP data. The nonlinear inversion reveals well resolved model features and informs the interpretation through a better understanding of the possible models. This approach can also be used to evaluate possible station geometries in order to optimize networks prior to deployment.

  11. Monte Carlo implementation of polarized hadronization

    Science.gov (United States)

    Matevosyan, Hrayr H.; Kotzinian, Aram; Thomas, Anthony W.

    2017-01-01

    We study the polarized quark hadronization in a Monte Carlo (MC) framework based on the recent extension of the quark-jet framework, where a self-consistent treatment of the quark polarization transfer in a sequential hadronization picture has been presented. Here, we first adopt this approach for MC simulations of the hadronization process with a finite number of produced hadrons, expressing the relevant probabilities in terms of the eight leading twist quark-to-quark transverse-momentum-dependent (TMD) splitting functions (SFs) for elementary q →q'+h transition. We present explicit expressions for the unpolarized and Collins fragmentation functions (FFs) of unpolarized hadrons emitted at rank 2. Further, we demonstrate that all the current spectator-type model calculations of the leading twist quark-to-quark TMD SFs violate the positivity constraints, and we propose a quark model based ansatz for these input functions that circumvents the problem. We validate our MC framework by explicitly proving the absence of unphysical azimuthal modulations of the computed polarized FFs, and by precisely reproducing the earlier derived explicit results for rank-2 pions. Finally, we present the full results for pion unpolarized and Collins FFs, as well as the corresponding analyzing powers from high statistics MC simulations with a large number of produced hadrons for two different model input elementary SFs. The results for both sets of input functions exhibit the same general features of an opposite signed Collins function for favored and unfavored channels at large z and, at the same time, demonstrate the flexibility of the quark-jet framework by producing significantly different dependences of the results at mid to low z for the two model inputs.

  12. Quantum Monte Carlo with directed loops.

    Science.gov (United States)

    Syljuåsen, Olav F; Sandvik, Anders W

    2002-10-01

    We introduce the concept of directed loops in stochastic series expansion and path-integral quantum Monte Carlo methods. Using the detailed balance rules for directed loops, we show that it is possible to smoothly connect generally applicable simulation schemes (in which it is necessary to include backtracking processes in the loop construction) to more restricted loop algorithms that can be constructed only for a limited range of Hamiltonians (where backtracking can be avoided). The "algorithmic discontinuities" between general and special points (or regions) in parameter space can hence be eliminated. As a specific example, we consider the anisotropic S=1/2 Heisenberg antiferromagnet in an external magnetic field. We show that directed-loop simulations are very efficient for the full range of magnetic fields (zero to the saturation point) and anisotropies. In particular, for weak fields and anisotropies, the autocorrelations are significantly reduced relative to those of previous approaches. The back-tracking probability vanishes continuously as the isotropic Heisenberg point is approached. For the XY model, we show that back tracking can be avoided for all fields extending up to the saturation field. The method is hence particularly efficient in this case. We use directed-loop simulations to study the magnetization process in the two-dimensional Heisenberg model at very low temperatures. For LxL lattices with L up to 64, we utilize the step structure in the magnetization curve to extract gaps between different spin sectors. Finite-size scaling of the gaps gives an accurate estimate of the transverse susceptibility in the thermodynamic limit: chi( perpendicular )=0.0659+/-0.0002.

  13. Monte Carlo simulation of large electron fields

    Science.gov (United States)

    Faddegon, Bruce A.; Perl, Joseph; Asai, Makoto

    2008-03-01

    Two Monte Carlo systems, EGSnrc and Geant4, the latter with two different 'physics lists,' were used to calculate dose distributions in large electron fields used in radiotherapy. Source and geometry parameters were adjusted to match calculated results to measurement. Both codes were capable of accurately reproducing the measured dose distributions of the six electron beams available on the accelerator. Depth penetration matched the average measured with a diode and parallel-plate chamber to 0.04 cm or better. Calculated depth dose curves agreed to 2% with diode measurements in the build-up region, although for the lower beam energies there was a discrepancy of up to 5% in this region when calculated results are compared to parallel-plate measurements. Dose profiles at the depth of maximum dose matched to 2-3% in the central 25 cm of the field, corresponding to the field size of the largest applicator. A 4% match was obtained outside the central region. The discrepancy observed in the bremsstrahlung tail in published results that used EGS4 is no longer evident. Simulations with the different codes and physics lists used different source energies, incident beam angles, thicknesses of the primary foils, and distance between the primary and secondary foil. The true source and geometry parameters were not known with sufficient accuracy to determine which parameter set, including the energy of the source, was closest to the truth. These results underscore the requirement for experimental benchmarks of depth penetration and electron scatter for beam energies and foils relevant to radiotherapy.

  14. kmos: A lattice kinetic Monte Carlo framework

    Science.gov (United States)

    Hoffmann, Max J.; Matera, Sebastian; Reuter, Karsten

    2014-07-01

    Kinetic Monte Carlo (kMC) simulations have emerged as a key tool for microkinetic modeling in heterogeneous catalysis and other materials applications. Systems, where site-specificity of all elementary reactions allows a mapping onto a lattice of discrete active sites, can be addressed within the particularly efficient lattice kMC approach. To this end we describe the versatile kmos software package, which offers a most user-friendly implementation, execution, and evaluation of lattice kMC models of arbitrary complexity in one- to three-dimensional lattice systems, involving multiple active sites in periodic or aperiodic arrangements, as well as site-resolved pairwise and higher-order lateral interactions. Conceptually, kmos achieves a maximum runtime performance which is essentially independent of lattice size by generating code for the efficiency-determining local update of available events that is optimized for a defined kMC model. For this model definition and the control of all runtime and evaluation aspects kmos offers a high-level application programming interface. Usage proceeds interactively, via scripts, or a graphical user interface, which visualizes the model geometry, the lattice occupations and rates of selected elementary reactions, while allowing on-the-fly changes of simulation parameters. We demonstrate the performance and scaling of kmos with the application to kMC models for surface catalytic processes, where for given operation conditions (temperature and partial pressures of all reactants) central simulation outcomes are catalytic activity and selectivities, surface composition, and mechanistic insight into the occurrence of individual elementary processes in the reaction network.

  15. Monte Carlo方法在催化研究中的应用%Monte Carlo Method Used in Catalytie Chemistry

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    介绍了以随机行走为基本特征的Monte Carlo方法的一般原理,以及Monte CarIo方法在多相催化研究中几个主要方面的应用情况,并对这一方法在催化中的应用前景作了一些展望。

  16. Monte Carlo Simulation in Digital Communication Systems%数字通信系统中的Monte Carlo仿真

    Institute of Scientific and Technical Information of China (English)

    高明慧

    2010-01-01

    介绍数字通信系统的广泛应用和Monte Carlo算法的基本思想,重点分析数字通信系统中的差错概率和应用Monte Carlo仿真对存在噪声和干扰的数字通信系统的性能进行评估.

  17. Monte Carlo Techniques for Nuclear Systems - Theory Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Forrest B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Monte Carlo Methods, Codes, and Applications Group; Univ. of New Mexico, Albuquerque, NM (United States). Nuclear Engineering Dept.

    2016-11-29

    These are lecture notes for a Monte Carlo class given at the University of New Mexico. The following topics are covered: course information; nuclear eng. review & MC; random numbers and sampling; computational geometry; collision physics; tallies and statistics; eigenvalue calculations I; eigenvalue calculations II; eigenvalue calculations III; variance reduction; parallel Monte Carlo; parameter studies; fission matrix and higher eigenmodes; doppler broadening; Monte Carlo depletion; HTGR modeling; coupled MC and T/H calculations; fission energy deposition. Solving particle transport problems with the Monte Carlo method is simple - just simulate the particle behavior. The devil is in the details, however. These lectures provide a balanced approach to the theory and practice of Monte Carlo simulation codes. The first lectures provide an overview of Monte Carlo simulation methods, covering the transport equation, random sampling, computational geometry, collision physics, and statistics. The next lectures focus on the state-of-the-art in Monte Carlo criticality simulations, covering the theory of eigenvalue calculations, convergence analysis, dominance ratio calculations, bias in Keff and tallies, bias in uncertainties, a case study of a realistic calculation, and Wielandt acceleration techniques. The remaining lectures cover advanced topics, including HTGR modeling and stochastic geometry, temperature dependence, fission energy deposition, depletion calculations, parallel calculations, and parameter studies. This portion of the class focuses on using MCNP to perform criticality calculations for reactor physics and criticality safety applications. It is an intermediate level class, intended for those with at least some familiarity with MCNP. Class examples provide hands-on experience at running the code, plotting both geometry and results, and understanding the code output. The class includes lectures & hands-on computer use for a variety of Monte Carlo calculations

  18. Reducing quasi-ergodicity in a double well potential by Tsallis Monte Carlo simulation

    OpenAIRE

    Iwamatsu, Masao; Okabe, Yutaka

    2000-01-01

    A new Monte Carlo scheme based on the system of Tsallis's generalized statistical mechanics is applied to a simple double well potential to calculate the canonical thermal average of potential energy. Although we observed serious quasi-ergodicity when using the standard Metropolis Monte Carlo algorithm, this problem is largely reduced by the use of the new Monte Carlo algorithm. Therefore the ergodicity is guaranteed even for short Monte Carlo steps if we use this new canonical Monte Carlo sc...

  19. Finding organic vapors - a Monte Carlo approach

    Science.gov (United States)

    Vuollekoski, Henri; Boy, Michael; Kerminen, Veli-Matti; Kulmala, Markku

    2010-05-01

    drawbacks in accuracy, the inability to find diurnal variation and the lack of size resolution. Here, we aim to shed some light onto the problem by applying an ad hoc Monte Carlo algorithm to a well established aerosol dynamical model, the University of Helsinki Multicomponent Aerosol model (UHMA). By performing a side-by-side comparison with measurement data within the algorithm, this approach has the significant advantage of decreasing the amount of manual labor. But more importantly, by basing the comparison on particle number size distribution data - a quantity that can be quite reliably measured - the accuracy of the results is good.

  20. Coherent Scattering Imaging Monte Carlo Simulation

    Science.gov (United States)

    Hassan, Laila Abdulgalil Rafik

    Conventional mammography has poor contrast between healthy and cancerous tissues due to the small difference in attenuation properties. Coherent scatter potentially provides more information because interference of coherently scattered radiation depends on the average intermolecular spacing, and can be used to characterize tissue types. However, typical coherent scatter analysis techniques are not compatible with rapid low dose screening techniques. Coherent scatter slot scan imaging is a novel imaging technique which provides new information with higher contrast. In this work a simulation of coherent scatter was performed for slot scan imaging to assess its performance and provide system optimization. In coherent scatter imaging, the coherent scatter is exploited using a conventional slot scan mammography system with anti-scatter grids tilted at the characteristic angle of cancerous tissues. A Monte Carlo simulation was used to simulate the coherent scatter imaging. System optimization was performed across several parameters, including source voltage, tilt angle, grid distances, grid ratio, and shielding geometry. The contrast increased as the grid tilt angle increased beyond the characteristic angle for the modeled carcinoma. A grid tilt angle of 16 degrees yielded the highest contrast and signal to noise ratio (SNR). Also, contrast increased as the source voltage increased. Increasing grid ratio improved contrast at the expense of decreasing SNR. A grid ratio of 10:1 was sufficient to give a good contrast without reducing the intensity to a noise level. The optimal source to sample distance was determined to be such that the source should be located at the focal distance of the grid. A carcinoma lump of 0.5x0.5x0.5 cm3 in size was detectable which is reasonable considering the high noise due to the usage of relatively small number of incident photons for computational reasons. A further study is needed to study the effect of breast density and breast thickness

  1. 'Bread Loaf' Mesa East of Phlegra Montes

    Science.gov (United States)

    2002-01-01

    [figure removed for brevity, see original site] An isolated mesa east of the Phlegra Montes in northeastern Elysium Planitia has a cracked surface that, combined with its overall shape, gives the appearance of a giant loaf of bread. Other mesas with similar surfaces are found in the area, suggesting that at one time these mesas were part of a continuous layer of material. It is likely that at that time, some process caused the graben-like cracks to form. Later erosion of the cracked layer left only the isolated mesas seen in the THEMIS image. One clue that supports this scenario is the presence of many filled and eroded craters throughout the scene but no fresh ones. One way to produce this landscape begins with an ancient and heavily cratered surface that subsequently is buried by some other material. If this overburden was stripped off relatively recently, not enough time would have passed to allow for a new population of fresh craters to be produced. The result would be a landscape with isolated mesas of younger material on top of an ancient, cratered surface.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey

  2. Competition between anisotropy and dipolar interaction in multicore nanoparticles: Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Juanita Londoño-Navarro

    2015-01-01

    Full Text Available Se realizaron simulaciones computacionales empleando Monte Carlo combinado con el modelo de Heisenberg y el algoritmo de Metropolis con el fin de estudiar las propiedades de equilibrio magnético en nano partículas multi-núcleo de magnetita. Se consideraron tres tipos de efectos: Interacción Zeeman, anisotropía magneto cristalina e interacción dipolar. Se observó una reducción en la magnetización debido a la influencia de la interacción dipolar y la anisotropía. Se estudió el efecto de la distribución de tamaños (diámetro medio y desviación estándar en la magnetización de las nano partículas, obteniéndose un mejor comportamiento magnético para tamaños grandes, ya que, en este caso se reduce la influencia del término de interacción dipolar. Se estudió además el efecto de la temperatura y de la dirección del eje fácil de magnetización sobre las propiedades magnéticas.

  3. Monte Carlo simulation of epitaxial growth of GaInAsSb films

    Directory of Open Access Journals (Sweden)

    Jheison Alejandro Morales

    2014-01-01

    Full Text Available El estudio de la fabricación de películas semiconductoras por l a técnica de Epitaxia en Fase Líquida a través de métodos de si mulación es un importante soporte en la ingeniería de estos materiales pues permite determinar la influencia de condiciones de crecimiento sobre las propiedades de las películas epitaxiales, variando a voluntad c iertos parámetros que experimentalmente conllevan exigentes con diciones de crecimiento y altos costos. En este trabajo se presenta la s imulación mediante tres diferentes métodos, del crecimiento epi taxial del material GaInAsSb con interesantes aplicaciones en dispositivos de generación de energía termofotovoltaica. Se utilizó la apro ximación de sólido sobre sólido suponiendo que la celda unitaria contiene l os cuatro elementos precursores en proporciones correspondiente s a la estequiometría seleccionada. Se determina que el método de Mont e Carlo cinético arroja los mejores resultados, mostrando una b uena coincidencia entre la morfología de las películas simuladas con la de películas fabricadas por esta técnica experimental.

  4. Alexander von Humboldt und Carlos Montúfar als Reisegefährten: ein Vergleich ihrer Tagebücher zum Chimborazo-Aufstieg

    Directory of Open Access Journals (Sweden)

    Reinhard Andress

    2011-03-01

    Full Text Available ZusammenfassungAls Alexander von Humboldt im Juni 1802 von Quito aus zum Rest seiner lateinamerikanischen Forschungsreise aufbrach, begleitete ihn, abgesehen von Aimé Bonpland, Carlos Montúfar bis nach Europa zurück begleitet, u.a. auch auf beim Versuch, den Chimborazo zu ersteigen. Bis kurz vor der Stadt Cajamarca im heutigen Peru schrieb Montúfar ein relativ unbekanntes Tagebuch zur Reise. Nach einem kurzen Ausflug in das Leben von Humboldts Begleiter steht im Zentrum der weiteren Ausführungen die Frage, ob sein Tagebuch ein anderes Licht auf Humboldt und speziell auf den Aufstiegsversuch wirft. Das läuft auf einen Vergleich der Tagebücher der beiden Reisegefährten hinaus und auf den Versuch, die scheinbaren Widersprüche aufzulösen.AbstractWhen Alexander von Humboldt left Quito in June 1802 in order to undertake the rest of his Latin-American trip of exploration, he was accompanied, aside from Aimé Bonpland, by Carlos Montúfar all the way back to Europe, including the attempt to scale the Chimborazo. Up to shortly before the city of Cajamarca in today’s Peru, Montúfar wrote an relatively unknown diary account of their travels. After a brief excursion into the life of Humboldt’s companion, the question is considered whether his diary sheds a different light on Humboldt and specifically on the mountain climb. That amounts to a comparison of the diaries of the two travel companions and to an attempt to explain the apparent contradictions.ResumenCuando Alexander von Humboldt salió de Quito en junio de 1802 para continuar con el resto de su viaje de exploración por la América Latina, fue acompañado por Carlos Montúfar además de Aimé Bonpland hasta que volvieron a Europa. Este trayecto incluía la tentativa de llegar a la cima del Chimborazo. Hasta un poco antes de la cuidad de Cajamarca que está en el Perú de hoy día, Montúfar mantenía un diario relativamente no conocido del viaje. Después de una breve excursión por

  5. An Unbiased Hessian Representation for Monte Carlo PDFs

    CERN Document Server

    Carrazza, Stefano; Kassabov, Zahari; Latorre, Jose Ignacio; Rojo, Juan

    2015-01-01

    We develop a methodology for the construction of a Hessian representation of Monte Carlo sets of parton distributions, based on the use of a subset of the Monte Carlo PDF replicas as an unbiased linear basis, and of a genetic algorithm for the determination of the optimal basis. We validate the methodology by first showing that it faithfully reproduces a native Monte Carlo PDF set (NNPDF3.0), and then, that if applied to Hessian PDF set (MMHT14) which was transformed into a Monte Carlo set, it gives back the starting PDFs with minimal information loss. We then show that, when applied to a large Monte Carlo PDF set obtained as combination of several underlying sets, the methodology leads to a Hessian representation in terms of a rather smaller set of parameters (CMC-H PDFs), thereby providing an alternative implementation of the recently suggested Meta-PDF idea and a Hessian version of the recently suggested PDF compression algorithm (CMC-PDFs). The mc2hessian conversion code is made publicly available togethe...

  6. An unbiased Hessian representation for Monte Carlo PDFs

    Energy Technology Data Exchange (ETDEWEB)

    Carrazza, Stefano; Forte, Stefano [Universita di Milano, TIF Lab, Dipartimento di Fisica, Milan (Italy); INFN, Sezione di Milano (Italy); Kassabov, Zahari [Universita di Milano, TIF Lab, Dipartimento di Fisica, Milan (Italy); Universita di Torino, Dipartimento di Fisica, Turin (Italy); INFN, Sezione di Torino (Italy); Latorre, Jose Ignacio [Universitat de Barcelona, Departament d' Estructura i Constituents de la Materia, Barcelona (Spain); Rojo, Juan [University of Oxford, Rudolf Peierls Centre for Theoretical Physics, Oxford (United Kingdom)

    2015-08-15

    We develop a methodology for the construction of a Hessian representation of Monte Carlo sets of parton distributions, based on the use of a subset of the Monte Carlo PDF replicas as an unbiased linear basis, and of a genetic algorithm for the determination of the optimal basis. We validate the methodology by first showing that it faithfully reproduces a native Monte Carlo PDF set (NNPDF3.0), and then, that if applied to Hessian PDF set (MMHT14) which was transformed into a Monte Carlo set, it gives back the starting PDFs with minimal information loss. We then show that, when applied to a large Monte Carlo PDF set obtained as combination of several underlying sets, the methodology leads to a Hessian representation in terms of a rather smaller set of parameters (MC-H PDFs), thereby providing an alternative implementation of the recently suggested Meta-PDF idea and a Hessian version of the recently suggested PDF compression algorithm (CMC-PDFs). The mc2hessian conversion code is made publicly available together with (through LHAPDF6) a Hessian representations of the NNPDF3.0 set, and the MC-H PDF set. (orig.)

  7. MONASTERIOS EN LA CIUDAD DE SOFIA. POTENCIALIDAD DEL VIAJE DE PEREGRINACIÓN Y DESARROLLO TURÍSTICO

    Directory of Open Access Journals (Sweden)

    Milena Hruleva

    2013-01-01

    Full Text Available El presente artículo trata de analizar las posibilidades de desarrollo de los viajes pere- grinos y el turismo religioso en los monasterios del Monte Sagrado de Sofía (Bulgaria. En primer lugar se describen los viajes de peregrinación como un producto turístico específico y se explica la importancia de la planificación estratégica como instrumento para diversifi- car la oferta de un destino turístico. A través del estudio se describe el espacio del entorno religioso del Monte Sagrado y sus principales características como centro de peregrinación devocional. Se analiza la estrategia, el mercado turístico y la oferta de la capital de Bulgaria, la ciudad de Sofía, basada sobre todo en el turismo cultural y de negocios. Finalmente se valoran datos estadísticos para evaluar el potencial turístico del Monte Sagrado de Sofía, diseñar propuestas y afrontar algunos retos del futuro.

  8. Monte Carlo studies of model Langmuir monolayers.

    Science.gov (United States)

    Opps, S B; Yang, B; Gray, C G; Sullivan, D E

    2001-04-01

    This paper examines some of the basic properties of a model Langmuir monolayer, consisting of surfactant molecules deposited onto a water subphase. The surfactants are modeled as rigid rods composed of a head and tail segment of diameters sigma(hh) and sigma(tt), respectively. The tails consist of n(t) approximately 4-7 effective monomers representing methylene groups. These rigid rods interact via site-site Lennard-Jones potentials with different interaction parameters for the tail-tail, head-tail, and head-head interactions. In a previous paper, we studied the ground-state properties of this system using a Landau approach. In the present paper, Monte Carlo simulations were performed in the canonical ensemble to elucidate the finite-temperature behavior of this system. Simulation techniques, incorporating a system of dynamic filters, allow us to decrease CPU time with negligible statistical error. This paper focuses on several of the key parameters, such as density, head-tail diameter mismatch, and chain length, responsible for driving transitions from uniformly tilted to untilted phases and between different tilt-ordered phases. Upon varying the density of the system, with sigma(hh)=sigma(tt), we observe a transition from a tilted (NNN)-condensed phase to an untilted-liquid phase and, upon comparison with recent experiments with fatty acid-alcohol and fatty acid-ester mixtures [M. C. Shih, M. K. Durbin, A. Malik, P. Zschack, and P. Dutta, J. Chem. Phys. 101, 9132 (1994); E. Teer, C. M. Knobler, C. Lautz, S. Wurlitzer, J. Kildae, and T. M. Fischer, J. Chem. Phys. 106, 1913 (1997)], we identify this as the L'(2)/Ov-L1 phase boundary. By varying the head-tail diameter ratio, we observe a decrease in T(c) with increasing mismatch. However, as the chain length was increased we observed that the transition temperatures increased and differences in T(c) due to head-tail diameter mismatch were diminished. In most of the present research, the water was treated as a hard

  9. La política de los Montes Protectores y su relación con los riesgos naturales en la provincia de Granada

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Mesa

    2015-01-01

    Full Text Available Ante el problema secular de deforestación que se padecía en la Península Ibérica y el relativofracaso de las políticas forestales que intentaron la restauración del arbolado, la administraciónmoderna intentó resolverlo sobre todo por sus repercusiones en los desastres naturales, medianteuna nueva fórmula. Esta consistió en la implantación de la figura de Monte Protector, mediantela Ley 24 de Junio de 1908 de Conservación de Montes y Repoblación Forestal. Esta figura finalmentesólo se implantaría en cuatro provincias, entre las que se encontraba la provincia de Granada.Su importancia radica en que marcará un hito en la consideración de los espacios públicosy privados como objeto de la ausencia de arbolado y lo que posteriormente significaría las políticasde repoblación de montes. En este trabajo se analizan las políticas de Montes Protectores enla provincia de Granada y su incidencia territorial, así como su relación con los riesgos naturales.

  10. Vectorizing and macrotasking Monte Carlo neutral particle algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Heifetz, D.B.

    1987-04-01

    Monte Carlo algorithms for computing neutral particle transport in plasmas have been vectorized and macrotasked. The techniques used are directly applicable to Monte Carlo calculations of neutron and photon transport, and Monte Carlo integration schemes in general. A highly vectorized code was achieved by calculating test flight trajectories in loops over arrays of flight data, isolating the conditional branches to as few a number of loops as possible. A number of solutions are discussed to the problem of gaps appearing in the arrays due to completed flights, which impede vectorization. A simple and effective implementation of macrotasking is achieved by dividing the calculation of the test flight profile among several processors. A tree of random numbers is used to ensure reproducible results. The additional memory required for each task may preclude using a larger number of tasks. In future machines, the limit of macrotasking may be possible, with each test flight, and split test flight, being a separate task.

  11. VARIATIONAL MONTE-CARLO APPROACH FOR ARTICULATED OBJECT TRACKING

    Directory of Open Access Journals (Sweden)

    Kartik Dwivedi

    2013-12-01

    Full Text Available In this paper, we describe a novel variational Monte Carlo approach for modeling and tracking body parts of articulated objects. An articulated object (human target is represented as a dynamic Markov network of the different constituent parts. The proposed approach combines local information of individual body parts and other spatial constraints influenced by neighboring parts. The movement of the relative parts of the articulated body is modeled with local information of displacements from the Markov network and the global information from other neighboring parts. We explore the effect of certain model parameters (including the number of parts tracked; number of Monte-Carlo cycles, etc. on system accuracy and show that ourvariational Monte Carlo approach achieves better efficiency and effectiveness compared to other methods on a number of real-time video datasets containing single targets.

  12. Meaningful timescales from Monte Carlo simulations of molecular systems

    CERN Document Server

    Costa, Liborio I

    2016-01-01

    A new Markov Chain Monte Carlo method for simulating the dynamics of molecular systems with atomistic detail is introduced. In contrast to traditional Kinetic Monte Carlo approaches, where the state of the system is associated with minima in the energy landscape, in the proposed method, the state of the system is associated with the set of paths traveled by the atoms and the transition probabilities for an atom to be displaced are proportional to the corresponding velocities. In this way, the number of possible state-to-state transitions is reduced to a discrete set, and a direct link between the Monte Carlo time step and true physical time is naturally established. The resulting rejection-free algorithm is validated against event-driven molecular dynamics: the equilibrium and non-equilibrium dynamics of hard disks converge to the exact results with decreasing displacement size.

  13. Sequential Monte Carlo on large binary sampling spaces

    CERN Document Server

    Schäfer, Christian

    2011-01-01

    A Monte Carlo algorithm is said to be adaptive if it automatically calibrates its current proposal distribution using past simulations. The choice of the parametric family that defines the set of proposal distributions is critical for a good performance. In this paper, we present such a parametric family for adaptive sampling on high-dimensional binary spaces. A practical motivation for this problem is variable selection in a linear regression context. We want to sample from a Bayesian posterior distribution on the model space using an appropriate version of Sequential Monte Carlo. Raw versions of Sequential Monte Carlo are easily implemented using binary vectors with independent components. For high-dimensional problems, however, these simple proposals do not yield satisfactory results. The key to an efficient adaptive algorithm are binary parametric families which take correlations into account, analogously to the multivariate normal distribution on continuous spaces. We provide a review of models for binar...

  14. Introduction to the variational and diffusion Monte Carlo methods

    CERN Document Server

    Toulouse, Julien; Umrigar, C J

    2015-01-01

    We provide a pedagogical introduction to the two main variants of real-space quantum Monte Carlo methods for electronic-structure calculations: variational Monte Carlo (VMC) and diffusion Monte Carlo (DMC). Assuming no prior knowledge on the subject, we review in depth the Metropolis-Hastings algorithm used in VMC for sampling the square of an approximate wave function, discussing details important for applications to electronic systems. We also review in detail the more sophisticated DMC algorithm within the fixed-node approximation, introduced to avoid the infamous Fermionic sign problem, which allows one to sample a more accurate approximation to the ground-state wave function. Throughout this review, we discuss the statistical methods used for evaluating expectation values and statistical uncertainties. In particular, we show how to estimate nonlinear functions of expectation values and their statistical uncertainties.

  15. Monte Carlo Methods for Tempo Tracking and Rhythm Quantization

    CERN Document Server

    Cemgil, A T; 10.1613/jair.1121

    2011-01-01

    We present a probabilistic generative model for timing deviations in expressive music performance. The structure of the proposed model is equivalent to a switching state space model. The switch variables correspond to discrete note locations as in a musical score. The continuous hidden variables denote the tempo. We formulate two well known music recognition problems, namely tempo tracking and automatic transcription (rhythm quantization) as filtering and maximum a posteriori (MAP) state estimation tasks. Exact computation of posterior features such as the MAP state is intractable in this model class, so we introduce Monte Carlo methods for integration and optimization. We compare Markov Chain Monte Carlo (MCMC) methods (such as Gibbs sampling, simulated annealing and iterative improvement) and sequential Monte Carlo methods (particle filters). Our simulation results suggest better results with sequential methods. The methods can be applied in both online and batch scenarios such as tempo tracking and transcr...

  16. Development of ray tracing visualization program by Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Kenji; Otani, Takayuki [Japan Atomic Energy Research Inst., Tokyo (Japan); Hasegawa, Yukihiro

    1997-09-01

    Ray tracing algorithm is a powerful method to synthesize three dimensional computer graphics. In conventional ray tracing algorithms, a view point is used as a starting point of ray tracing, from which the rays are tracked up to the light sources through center points of pixels on the view screen to calculate the intensities of the pixels. This manner, however, makes it difficult to define the configuration of light source as well as to strictly simulate the reflections of the rays. To resolve these problems, we have developed a new ray tracing means which traces rays from a light source, not from a view point, with use of Monte Carlo method which is widely applied in nuclear fields. Moreover, we adopt the variance reduction techniques to the program with use of the specialized machine (Monte-4) for particle transport Monte Carlo so that the computational time could be successfully reduced. (author)

  17. Efficiency of Monte Carlo sampling in chaotic systems.

    Science.gov (United States)

    Leitão, Jorge C; Lopes, J M Viana Parente; Altmann, Eduardo G

    2014-11-01

    In this paper we investigate how the complexity of chaotic phase spaces affect the efficiency of importance sampling Monte Carlo simulations. We focus on flat-histogram simulations of the distribution of finite-time Lyapunov exponent in a simple chaotic system and obtain analytically that the computational effort: (i) scales polynomially with the finite time, a tremendous improvement over the exponential scaling obtained in uniform sampling simulations; and (ii) the polynomial scaling is suboptimal, a phenomenon known as critical slowing down. We show that critical slowing down appears because of the limited possibilities to issue a local proposal in the Monte Carlo procedure when it is applied to chaotic systems. These results show how generic properties of chaotic systems limit the efficiency of Monte Carlo simulations.

  18. Monte Carlo simulation of laser attenuation characteristics in fog

    Science.gov (United States)

    Wang, Hong-Xia; Sun, Chao; Zhu, You-zhang; Sun, Hong-hui; Li, Pan-shi

    2011-06-01

    Based on the Mie scattering theory and the gamma size distribution model, the scattering extinction parameter of spherical fog-drop is calculated. For the transmission attenuation of the laser in the fog, a Monte Carlo simulation model is established, and the impact of attenuation ratio on visibility and field angle is computed and analysed using the program developed by MATLAB language. The results of the Monte Carlo method in this paper are compared with the results of single scattering method. The results show that the influence of multiple scattering need to be considered when the visibility is low, and single scattering calculations have larger errors. The phenomenon of multiple scattering can be interpreted more better when the Monte Carlo is used to calculate the attenuation ratio of the laser transmitting in the fog.

  19. Calibration and Monte Carlo modelling of neutron long counters

    CERN Document Server

    Tagziria, H

    2000-01-01

    The Monte Carlo technique has become a very powerful tool in radiation transport as full advantage is taken of enhanced cross-section data, more powerful computers and statistical techniques, together with better characterisation of neutron and photon source spectra. At the National Physical Laboratory, calculations using the Monte Carlo radiation transport code MCNP-4B have been combined with accurate measurements to characterise two long counters routinely used to standardise monoenergetic neutron fields. New and more accurate response function curves have been produced for both long counters. A novel approach using Monte Carlo methods has been developed, validated and used to model the response function of the counters and determine more accurately their effective centres, which have always been difficult to establish experimentally. Calculations and measurements agree well, especially for the De Pangher long counter for which details of the design and constructional material are well known. The sensitivit...

  20. The Monte Carlo method in quantum field theory

    CERN Document Server

    Morningstar, C

    2007-01-01

    This series of six lectures is an introduction to using the Monte Carlo method to carry out nonperturbative studies in quantum field theories. Path integrals in quantum field theory are reviewed, and their evaluation by the Monte Carlo method with Markov-chain based importance sampling is presented. Properties of Markov chains are discussed in detail and several proofs are presented, culminating in the fundamental limit theorem for irreducible Markov chains. The example of a real scalar field theory is used to illustrate the Metropolis-Hastings method and to demonstrate the effectiveness of an action-preserving (microcanonical) local updating algorithm in reducing autocorrelations. The goal of these lectures is to provide the beginner with the basic skills needed to start carrying out Monte Carlo studies in quantum field theories, as well as to present the underlying theoretical foundations of the method.

  1. Properties of Reactive Oxygen Species by Quantum Monte Carlo

    CERN Document Server

    Zen, Andrea; Guidoni, Leonardo

    2014-01-01

    The electronic properties of the oxygen molecule, in its singlet and triplet states, and of many small oxygen-containing radicals and anions have important roles in different fields of Chemistry, Biology and Atmospheric Science. Nevertheless, the electronic structure of such species is a challenge for ab-initio computational approaches because of the difficulties to correctly describe the statical and dynamical correlation effects in presence of one or more unpaired electrons. Only the highest-level quantum chemical approaches can yield reliable characterizations of their molecular properties, such as binding energies, equilibrium structures, molecular vibrations, charge distribution and polarizabilities. In this work we use the variational Monte Carlo (VMC) and the lattice regularized Monte Carlo (LRDMC) methods to investigate the equilibrium geometries and molecular properties of oxygen and oxygen reactive species. Quantum Monte Carlo methods are used in combination with the Jastrow Antisymmetrized Geminal ...

  2. Optimised Iteration in Coupled Monte Carlo - Thermal-Hydraulics Calculations

    Science.gov (United States)

    Hoogenboom, J. Eduard; Dufek, Jan

    2014-06-01

    This paper describes an optimised iteration scheme for the number of neutron histories and the relaxation factor in successive iterations of coupled Monte Carlo and thermal-hydraulic reactor calculations based on the stochastic iteration method. The scheme results in an increasing number of neutron histories for the Monte Carlo calculation in successive iteration steps and a decreasing relaxation factor for the spatial power distribution to be used as input to the thermal-hydraulics calculation. The theoretical basis is discussed in detail and practical consequences of the scheme are shown, among which a nearly linear increase per iteration of the number of cycles in the Monte Carlo calculation. The scheme is demonstrated for a full PWR type fuel assembly. Results are shown for the axial power distribution during several iteration steps. A few alternative iteration method are also tested and it is concluded that the presented iteration method is near optimal.

  3. TAKING THE NEXT STEP WITH INTELLIGENT MONTE CARLO

    Energy Technology Data Exchange (ETDEWEB)

    Booth, T.E.; Carlson, J.A. [and others

    2000-10-01

    For many scientific calculations, Monte Carlo is the only practical method available. Unfortunately, standard Monte Carlo methods converge slowly as the square root of the computer time. We have shown, both numerically and theoretically, that the convergence rate can be increased dramatically if the Monte Carlo algorithm is allowed to adapt based on what it has learned from previous samples. As the learning continues, computational efficiency increases, often geometrically fast. The particle transport work achieved geometric convergence for a two-region problem as well as for problems with rapidly changing nuclear data. The statistics work provided theoretical proof of geometic convergence for continuous transport problems and promising initial results for airborne migration of particles. The statistical physics work applied adaptive methods to a variety of physical problems including the three-dimensional Ising glass, quantum scattering, and eigenvalue problems.

  4. Monte Carlo tests of the ELIPGRID-PC algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, J.R.

    1995-04-01

    The standard tool for calculating the probability of detecting pockets of contamination called hot spots has been the ELIPGRID computer code of Singer and Wickman. The ELIPGRID-PC program has recently made this algorithm available for an IBM{reg_sign} PC. However, no known independent validation of the ELIPGRID algorithm exists. This document describes a Monte Carlo simulation-based validation of a modified version of the ELIPGRID-PC code. The modified ELIPGRID-PC code is shown to match Monte Carlo-calculated hot-spot detection probabilities to within {plus_minus}0.5% for 319 out of 320 test cases. The one exception, a very thin elliptical hot spot located within a rectangular sampling grid, differed from the Monte Carlo-calculated probability by about 1%. These results provide confidence in the ability of the modified ELIPGRID-PC code to accurately predict hot-spot detection probabilities within an acceptable range of error.

  5. Failure Probability Estimation of Wind Turbines by Enhanced Monte Carlo

    DEFF Research Database (Denmark)

    Sichani, Mahdi Teimouri; Nielsen, Søren R.K.; Naess, Arvid

    2012-01-01

    This paper discusses the estimation of the failure probability of wind turbines required by codes of practice for designing them. The Standard Monte Carlo (SMC) simulations may be used for this reason conceptually as an alternative to the popular Peaks-Over-Threshold (POT) method. However......, estimation of very low failure probabilities with SMC simulations leads to unacceptably high computational costs. In this study, an Enhanced Monte Carlo (EMC) method is proposed that overcomes this obstacle. The method has advantages over both POT and SMC in terms of its low computational cost and accuracy...... is controlled by the pitch controller. This provides a fair framework for comparison of the behavior and failure event of the wind turbine with emphasis on the effect of the pitch controller. The Enhanced Monte Carlo method is then applied to the model and the failure probabilities of the model are estimated...

  6. Monte Carlo Simulation in Statistical Physics An Introduction

    CERN Document Server

    Binder, Kurt

    2010-01-01

    Monte Carlo Simulation in Statistical Physics deals with the computer simulation of many-body systems in condensed-matter physics and related fields of physics, chemistry and beyond, to traffic flows, stock market fluctuations, etc.). Using random numbers generated by a computer, probability distributions are calculated, allowing the estimation of the thermodynamic properties of various systems. This book describes the theoretical background to several variants of these Monte Carlo methods and gives a systematic presentation from which newcomers can learn to perform such simulations and to analyze their results. The fifth edition covers Classical as well as Quantum Monte Carlo methods. Furthermore a new chapter on the sampling of free-energy landscapes has been added. To help students in their work a special web server has been installed to host programs and discussion groups (http://wwwcp.tphys.uni-heidelberg.de). Prof. Binder was awarded the Berni J. Alder CECAM Award for Computational Physics 2001 as well ...

  7. Applicability of Quasi-Monte Carlo for lattice systems

    CERN Document Server

    Ammon, Andreas; Jansen, Karl; Leovey, Hernan; Griewank, Andreas; Müller-Preussker, Micheal

    2013-01-01

    This project investigates the applicability of quasi-Monte Carlo methods to Euclidean lattice systems in order to improve the asymptotic error scaling of observables for such theories. The error of an observable calculated by averaging over random observations generated from ordinary Monte Carlo simulations scales like $N^{-1/2}$, where $N$ is the number of observations. By means of quasi-Monte Carlo methods it is possible to improve this scaling for certain problems to $N^{-1}$, or even further if the problems are regular enough. We adapted and applied this approach to simple systems like the quantum harmonic and anharmonic oscillator and verified an improved error scaling of all investigated observables in both cases.

  8. Implementation of Monte Carlo Simulations for the Gamma Knife System

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, W [Memorial Sloan-Kettering Cancer Center/Mercy Medical Center, 1000 N Village Ave., Rockville Centre, NY 11570 (United States); Huang, D [Memorial Sloan-Kettering Cancer Center/Mercy Medical Center, 1000 N Village Ave., Rockville Centre, NY 11570 (United States); Lee, L [Memorial Sloan-Kettering Cancer Center/Mercy Medical Center, 1000 N Village Ave., Rockville Centre, NY 11570 (United States); Feng, J [Memorial Sloan-Kettering Cancer Center/Mercy Medical Center, 1000 N Village Ave., Rockville Centre, NY 11570 (United States); Morris, K [Memorial Sloan-Kettering Cancer Center/Mercy Medical Center, 1000 N Village Ave., Rockville Centre, NY 11570 (United States); Calugaru, E [Memorial Sloan-Kettering Cancer Center/Mercy Medical Center, 1000 N Village Ave., Rockville Centre, NY 11570 (United States); Burman, C [Memorial Sloan-Kettering Cancer Center/Mercy Medical Center, 1000 N Village Ave., Rockville Centre, NY 11570 (United States); Li, J [Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 17111 (United States); Ma, C-M [Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 17111 (United States)

    2007-06-15

    Currently the Gamma Knife system is accompanied with a treatment planning system, Leksell GammaPlan (LGP) which is a standard, computer-based treatment planning system for Gamma Knife radiosurgery. In LGP, the dose calculation algorithm does not consider the scatter dose contributions and the inhomogeneity effect due to the skull and air cavities. To improve the dose calculation accuracy, Monte Carlo simulations have been implemented for the Gamma Knife planning system. In this work, the 201 Cobalt-60 sources in the Gamma Knife unit are considered to have the same activity. Each Cobalt-60 source is contained in a cylindric stainless steel capsule. The particle phase space information is stored in four beam data files, which are collected in the inner sides of the 4 treatment helmets, after the Cobalt beam passes through the stationary and helmet collimators. Patient geometries are rebuilt from patient CT data. Twenty two Patients are included in the Monte Carlo simulation for this study. The dose is calculated using Monte Carlo in both homogenous and inhomogeneous geometries with identical beam parameters. To investigate the attenuation effect of the skull bone the dose in a 16cm diameter spherical QA phantom is measured with and without a 1.5mm Lead-covering and also simulated using Monte Carlo. The dose ratios with and without the 1.5mm Lead-covering are 89.8% based on measurements and 89.2% according to Monte Carlo for a 18mm-collimator Helmet. For patient geometries, the Monte Carlo results show that although the relative isodose lines remain almost the same with and without inhomogeneity corrections, the difference in the absolute dose is clinically significant. The average inhomogeneity correction is (3.9 {+-} 0.90) % for the 22 patients investigated. These results suggest that the inhomogeneity effect should be considered in the dose calculation for Gamma Knife treatment planning.

  9. Mission Analysis, Operations, and Navigation Toolkit Environment (Monte) Version 040

    Science.gov (United States)

    Sunseri, Richard F.; Wu, Hsi-Cheng; Evans, Scott E.; Evans, James R.; Drain, Theodore R.; Guevara, Michelle M.

    2012-01-01

    Monte is a software set designed for use in mission design and spacecraft navigation operations. The system can process measurement data, design optimal trajectories and maneuvers, and do orbit determination, all in one application. For the first time, a single software set can be used for mission design and navigation operations. This eliminates problems due to different models and fidelities used in legacy mission design and navigation software. The unique features of Monte 040 include a blowdown thruster model for GRAIL (Gravity Recovery and Interior Laboratory) with associated pressure models, as well as an updated, optimalsearch capability (COSMIC) that facilitated mission design for ARTEMIS. Existing legacy software lacked the capabilities necessary for these two missions. There is also a mean orbital element propagator and an osculating to mean element converter that allows long-term orbital stability analysis for the first time in compiled code. The optimized trajectory search tool COSMIC allows users to place constraints and controls on their searches without any restrictions. Constraints may be user-defined and depend on trajectory information either forward or backwards in time. In addition, a long-term orbit stability analysis tool (morbiter) existed previously as a set of scripts on top of Monte. Monte is becoming the primary tool for navigation operations, a core competency at JPL. The mission design capabilities in Monte are becoming mature enough for use in project proposals as well as post-phase A mission design. Monte has three distinct advantages over existing software. First, it is being developed in a modern paradigm: object- oriented C++ and Python. Second, the software has been developed as a toolkit, which allows users to customize their own applications and allows the development team to implement requirements quickly, efficiently, and with minimal bugs. Finally, the software is managed in accordance with the CMMI (Capability Maturity Model

  10. Del territorio del sujeto al emplazamiento del Común

    Directory of Open Access Journals (Sweden)

    Mariano Adrían Ferretti

    2016-01-01

    Full Text Available La construcción de lo público abarca una variedad de dinámicas que condicionan el resultado físico de los espacios donde actúan los individuos en sus necesidades de habitar, modificando su realidad desde la diferenciación y la singularización subjetiva del entorno que derivan en nuevas formas de territorialidad de lo público a partir de la dialéctica entre lo público y lo privado. Sin embargo, los resultados de tales representaciones entendidas como acciones colectivas –y por tanto comunes- no siempre explican los valores que desde lo simbólico partiendo del sujeto constituyan un estatus diferente de lo público en los procesos de territorialización. Se propone una aproximación que aborde de manera teórica cuestiones tales como: los vínculos del individuo con los procesos de acumulación material y transformación del territorio y las implicaciones que dichos fenómenos tienen en la posibilidad de constitución de un sujeto que trascendiendo al individuo sea capaz de conformar un nuevo estatus del sujeto o, dicho de otro modo, un emplazamiento del Común.

  11. A standard Event Class for Monte Carlo Generators

    Institute of Scientific and Technical Information of China (English)

    L.A.Gerren; M.Fischler

    2001-01-01

    StdHepC++[1]is a CLHEP[2] Monte Carlo event class library which provides a common interface to Monte Carlo Event Generators,This work is an extensive redesign of the StdHep Fortran interface to use the full power of object oriented design,A generated event maps naturally onto the Directed Acyclic Graph concept and we have used the HepMC classes to implement this.The full implementation allows the user to combine events to simulate beam pileup and access them transparently as though they were a single event.

  12. Parallelization of Monte Carlo codes MVP/GMVP

    Energy Technology Data Exchange (ETDEWEB)

    Nagaya, Yasunobu; Mori, Takamasa; Nakagawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Sasaki, Makoto

    1998-03-01

    General-purpose Monte Carlo codes MVP/GMVP are well-vectorized and thus enable us to perform high-speed Monte Carlo calculations. In order to achieve more speedups, we parallelized the codes on the different types of the parallel processing platforms. The platforms reported are a distributed-memory vector-parallel computer Fujitsu VPP500, a distributed-memory massively parallel computer Intel Paragon and a distributed-memory scalar-parallel computer Hitachi SR2201. As mentioned generally, ideal speedup could be obtained for large-scale problems but parallelization efficiency got worse as the batch size per a processing element (PE) was smaller. (author)

  13. Parton distribution functions in Monte Carlo factorisation scheme

    Science.gov (United States)

    Jadach, S.; Płaczek, W.; Sapeta, S.; Siódmok, A.; Skrzypek, M.

    2016-12-01

    A next step in development of the KrkNLO method of including complete NLO QCD corrections to hard processes in a LO parton-shower Monte Carlo is presented. It consists of a generalisation of the method, previously used for the Drell-Yan process, to Higgs-boson production. This extension is accompanied with the complete description of parton distribution functions in a dedicated, Monte Carlo factorisation scheme, applicable to any process of production of one or more colour-neutral particles in hadron-hadron collisions.

  14. PEPSI — a Monte Carlo generator for polarized leptoproduction

    Science.gov (United States)

    Mankiewicz, L.; Schäfer, A.; Veltri, M.

    1992-09-01

    We describe PEPSI (Polarized Electron Proton Scattering Interactions), a Monte Carlo program for polarized deep inelastic leptoproduction mediated by electromagnetic interaction, and explain how to use it. The code is a modification of the LEPTO 4.3 Lund Monte Carlo for unpolarized scattering. The hard virtual gamma-parton scattering is generated according to the polarization-dependent QCD cross-section of the first order in α S. PEPSI requires the standard polarization-independent JETSET routines to simulate the fragmentation into final hadrons.

  15. Utilising Monte Carlo Simulation for the Valuation of Mining Concessions

    Directory of Open Access Journals (Sweden)

    Rosli Said

    2005-12-01

    Full Text Available Valuation involves the analyses of various input data to produce an estimated value. Since each input is itself often an estimate, there is an element of uncertainty in the input. This leads to uncertainty in the resultant output value. It is argued that a valuation must also convey information on the uncertainty, so as to be more meaningful and informative to the user. The Monte Carlo simulation technique can generate the information on uncertainty and is therefore potentially useful to valuation. This paper reports on the investigation that has been conducted to apply Monte Carlo simulation technique in mineral valuation, more specifically, in the valuation of a quarry concession.

  16. Monte Carlo methods and models in finance and insurance

    CERN Document Server

    Korn, Ralf

    2010-01-01

    Offering a unique balance between applications and calculations, this book incorporates the application background of finance and insurance with the theory and applications of Monte Carlo methods. It presents recent methods and algorithms, including the multilevel Monte Carlo method, the statistical Romberg method, and the Heath-Platen estimator, as well as recent financial and actuarial models, such as the Cheyette and dynamic mortality models. The book enables readers to find the right algorithm for a desired application and illustrates complicated methods and algorithms with simple applicat

  17. Research in the Mont Terri Rock laboratory: Quo vadis?

    Science.gov (United States)

    Bossart, Paul; Thury, Marc

    During the past 10 years, the 12 Mont Terri partner organisations ANDRA, BGR, CRIEPI, ENRESA, FOWG (now SWISSTOPO), GRS, HSK, IRSN, JAEA, NAGRA, OBAYASHI and SCK-CEN have jointly carried out and financed a research programme in the Mont Terri Rock Laboratory. An important strategic question for the Mont Terri project is what type of new experiments should be carried out in the future. This question has been discussed among partner delegates, authorities, scientists, principal investigators and experiment delegates. All experiments at Mont Terri - past, ongoing and future - can be assigned to the following three categories: (1) process and mechanism understanding in undisturbed argillaceous formations, (2) experiments related to excavation- and repository-induced perturbations and (3) experiments related to repository performance during the operational and post-closure phases. In each of these three areas, there are still open questions and hence potential experiments to be carried out in the future. A selection of key issues and questions which have not, or have only partly been addressed so far and in which the project partners, but also the safety authorities and other research organisations may be interested, are presented in the following. The Mont Terri Rock Laboratory is positioned as a generic rock laboratory, where research and development is key: mainly developing methods for site characterisation of argillaceous formations, process understanding and demonstration of safety. Due to geological constraints, there will never be a site specific rock laboratory at Mont Terri. The added value for the 12 partners in terms of future experiments is threefold: (1) the Mont Terri project provides an international scientific platform of high reputation for research on radioactive waste disposal (= state-of-the-art research in argillaceous materials); (2) errors are explicitly allowed (= rock laboratory as a “playground” where experience is often gained through

  18. Accuracy Analysis of Assembly Success Rate with Monte Carlo Simulations

    Institute of Scientific and Technical Information of China (English)

    仲昕; 杨汝清; 周兵

    2003-01-01

    Monte Carlo simulation was applied to Assembly Success Rate (ASR) analyses.ASR of two peg-in-hole robot assemblies was used as an example by taking component parts' sizes,manufacturing tolerances and robot repeatability into account.A statistic arithmetic expression was proposed and deduced in this paper,which offers an alternative method of estimating the accuracy of ASR,without having to repeat the simulations.This statistic method also helps to choose a suitable sample size,if error reduction is desired.Monte Carlo simulation results demonstrated the feasibility of the method.

  19. THE APPLICATION OF MONTE CARLO SIMULATION FOR A DECISION PROBLEM

    Directory of Open Access Journals (Sweden)

    Çiğdem ALABAŞ

    2001-01-01

    Full Text Available The ultimate goal of the standard decision tree approach is to calculate the expected value of a selected performance measure. In the real-world situations, the decision problems become very complex as the uncertainty factors increase. In such cases, decision analysis using standard decision tree approach is not useful. One way of overcoming this difficulty is the Monte Carlo simulation. In this study, a Monte Carlo simulation model is developed for a complex problem and statistical analysis is performed to make the best decision.

  20. Applications of quantum Monte Carlo methods in condensed systems

    CERN Document Server

    Kolorenc, Jindrich

    2010-01-01

    The quantum Monte Carlo methods represent a powerful and broadly applicable computational tool for finding very accurate solutions of the stationary Schroedinger equation for atoms, molecules, solids and a variety of model systems. The algorithms are intrinsically parallel and are able to take full advantage of the present-day high-performance computing systems. This review article concentrates on the fixed-node/fixed-phase diffusion Monte Carlo method with emphasis on its applications to electronic structure of solids and other extended many-particle systems.

  1. Quasi-Monte Carlo methods for the Heston model

    OpenAIRE

    Jan Baldeaux; Dale Roberts

    2012-01-01

    In this paper, we discuss the application of quasi-Monte Carlo methods to the Heston model. We base our algorithms on the Broadie-Kaya algorithm, an exact simulation scheme for the Heston model. As the joint transition densities are not available in closed-form, the Linear Transformation method due to Imai and Tan, a popular and widely applicable method to improve the effectiveness of quasi-Monte Carlo methods, cannot be employed in the context of path-dependent options when the underlying pr...

  2. Novel Quantum Monte Carlo Approaches for Quantum Liquids

    Science.gov (United States)

    Rubenstein, Brenda M.

    Quantum Monte Carlo methods are a powerful suite of techniques for solving the quantum many-body problem. By using random numbers to stochastically sample quantum properties, QMC methods are capable of studying low-temperature quantum systems well beyond the reach of conventional deterministic techniques. QMC techniques have likewise been indispensible tools for augmenting our current knowledge of superfluidity and superconductivity. In this thesis, I present two new quantum Monte Carlo techniques, the Monte Carlo Power Method and Bose-Fermi Auxiliary-Field Quantum Monte Carlo, and apply previously developed Path Integral Monte Carlo methods to explore two new phases of quantum hard spheres and hydrogen. I lay the foundation for a subsequent description of my research by first reviewing the physics of quantum liquids in Chapter One and the mathematics behind Quantum Monte Carlo algorithms in Chapter Two. I then discuss the Monte Carlo Power Method, a stochastic way of computing the first several extremal eigenvalues of a matrix too memory-intensive to be stored and therefore diagonalized. As an illustration of the technique, I demonstrate how it can be used to determine the second eigenvalues of the transition matrices of several popular Monte Carlo algorithms. This information may be used to quantify how rapidly a Monte Carlo algorithm is converging to the equilibrium probability distribution it is sampling. I next present the Bose-Fermi Auxiliary-Field Quantum Monte Carlo algorithm. This algorithm generalizes the well-known Auxiliary-Field Quantum Monte Carlo algorithm for fermions to bosons and Bose-Fermi mixtures. Despite some shortcomings, the Bose-Fermi Auxiliary-Field Quantum Monte Carlo algorithm represents the first exact technique capable of studying Bose-Fermi mixtures of any size in any dimension. In Chapter Six, I describe a new Constant Stress Path Integral Monte Carlo algorithm for the study of quantum mechanical systems under high pressures. While

  3. Monte Carlo simulation of electron slowing down in indium

    Energy Technology Data Exchange (ETDEWEB)

    Rouabah, Z.; Hannachi, M. [Materials and Electronic Systems Laboratory (LMSE), University of Bordj Bou Arreridj, Bordj Bou Arreridj (Algeria); Champion, C. [Université de Bordeaux 1, CNRS/IN2P3, Centre d’Etudes Nucléaires de Bordeaux-Gradignan, (CENBG), Gradignan (France); Bouarissa, N., E-mail: n_bouarissa@yahoo.fr [Laboratory of Materials Physics and its Applications, University of M' sila, 28000 M' sila (Algeria)

    2015-07-15

    Highlights: • Electron scattering in indium targets. • Modeling of elastic cross-sections. • Monte Carlo simulation of low energy electrons. - Abstract: In the current study, we aim at simulating via a detailed Monte Carlo code, the electron penetration in a semi-infinite indium medium for incident energies ranging from 0.5 to 5 keV. Electron range, backscattering coefficients, mean penetration depths as well as stopping profiles are then reported. The results may be seen as the first predictions for low-energy electron penetration in indium target.

  4. Kinetic Monte Carlo method applied to nucleic acid hairpin folding.

    Science.gov (United States)

    Sauerwine, Ben; Widom, Michael

    2011-12-01

    Kinetic Monte Carlo on coarse-grained systems, such as nucleic acid secondary structure, is advantageous for being able to access behavior at long time scales, even minutes or hours. Transition rates between coarse-grained states depend upon intermediate barriers, which are not directly simulated. We propose an Arrhenius rate model and an intermediate energy model that incorporates the effects of the barrier between simulated states without enlarging the state space itself. Applying our Arrhenius rate model to DNA hairpin folding, we demonstrate improved agreement with experiment compared to the usual kinetic Monte Carlo model. Further improvement results from including rigidity of single-stranded stacking.

  5. Green's function monte carlo and the many-fermion problem

    Science.gov (United States)

    Kalos, M. H.

    The application of Green's function Monte Carlo to many body problems is outlined. For boson problems, the method is well developed and practical. An "efficiency principle",importance sampling, can be used to reduce variance. Fermion problems are more difficult because spatially antisymmetric functions must be represented as a difference of two density functions. Naively treated, this leads to a rapid growth of Monte Carlo error. Methods for overcoming the difficulty are discussed. Satisfactory algorithms exist for few-body problems; for many-body problems more work is needed, but it is likely that adequate methods will soon be available.

  6. Monte Carlo simulation of electrons in dense gases

    Science.gov (United States)

    Tattersall, Wade; Boyle, Greg; Cocks, Daniel; Buckman, Stephen; White, Ron

    2014-10-01

    We implement a Monte-Carlo simulation modelling the transport of electrons and positrons in dense gases and liquids, by using a dynamic structure factor that allows us to construct structure-modified effective cross sections. These account for the coherent effects caused by interactions with the relatively dense medium. The dynamic structure factor also allows us to model thermal gases in the same manner, without needing to directly sample the velocities of the neutral particles. We present the results of a series of Monte Carlo simulations that verify and apply this new technique, and make comparisons with macroscopic predictions and Boltzmann equation solutions. Financial support of the Australian Research Council.

  7. Cosmological Markov Chain Monte Carlo simulation with Cmbeasy

    CERN Document Server

    Müller, C M

    2004-01-01

    We introduce a Markov Chain Monte Carlo simulation and data analysis package for the cosmological computation package Cmbeasy. We have taken special care in implementing an adaptive step algorithm for the Markov Chain Monte Carlo in order to improve convergence. Data analysis routines are provided which allow to test models of the Universe against up-to-date measurements of the Cosmic Microwave Background, Supernovae Ia and Large Scale Structure. The observational data is provided with the software for convenient usage. The package is publicly available as part of the Cmbeasy software at www.cmbeasy.org.

  8. An analysis on the costs of Belo Monte hydroelectric power plant; Uma analise sobre os custos da hidreletrica Belo Monte

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcos Vinicius Miranda da [Universidade de Sao Paulo (PIPGE/USP), SP (Brazil). Programa Interunidades de Pos-Graduacao em Energia], e-mail: energiapara@yahoo.com.br

    2008-07-01

    The Belo Monte hydropower plant's low generation cost is among the arguments used by Centrais Eletricas do Norte do Brazil (ELETRONORTE), a Brazilian state electric utility, to make possible its construction. This paper shows that the generation cost presented by ELETROBRAS is very low in relation to the world pattern of cost and probably unrealistic. It also shows that the generation cost cannot be used separately to determine the Belo Monte dam's economic feasibility. There is the need to include other costs, such as: socio environmental degradation and control, financial compensation for using the hydraulic resources, transmission and thermal backup stations, beyond, evidently, generation cost for assuring the credibility of the Belo Monte hydropower plant's economic analysis. (author)

  9. Historia del genoma humano

    OpenAIRE

    Castaño Valencia, Óscar

    2006-01-01

    En 1990 el Doctor Charles de Lisi presentó el proyecto del GENOMA HUMANO en asocio del Instituto de Salud Americano, el Instituto Whithead de Cambridge, la Universidad de Washingtong, el Colegio Médico de Baylor y el Instituto del Genoma Humano, de California.Estos organismos han venido actuando desde esa época, contando con la financiación de los gobiernos del Japón, Alemania, Francia, China y naturalmente del americano.En sus fases iniciales fue orientado por el Dr. James Watson quien contó...

  10. Los nudos del sistema

    OpenAIRE

    2000-01-01

    Pieza central del antiguo régimen; pacto, acuerdo o trato con algunos actores decisivos del sistema político susceptible de ser revisado; forma cultural de relaciones de poder o de intercambio; pirámide de organizaciones o estructura sectorial: ¿qué tan invisible sigue siendo, qué tan montada sigue estando la pirámide del corporativismo mexicano antes y después del 2 de julio de 2000? Este fenómeno constituye el eje central de las reflexiones del presente ensayo. En torno al mismo, se pres...

  11. Algunas Cerámicas Ibéricas Decoradas del «Castro Plaza del Tercio» (Torrecillas de la Tiesa, Caceres

    Directory of Open Access Journals (Sweden)

    María Cleofé RIVERO DE LA HIGUERA

    2009-10-01

    Full Text Available La existencia de este castro me la notificó D. Juan Gil Montes, licenciado en Ciencias Geológicas y profesor en la actualidad de la Universidad Laboral de Càceres, quien me mandaba en la carta un croquis del yacimiento y un dibujo esquemático de la pieza n.° 1. El Dr. Jordá a la vista de la importancia del mismo, me entregó una carta dirigida a los hermanos Sánchez-Vallarino de Trujillo, a fin de que me dejaran ver el castro, ubicado en su finca «La Coraja».

  12. Monte-Carlo Statistical Iteration Image Reconstruction Algorithm%Monte-Carlo统计迭代图像重建算法

    Institute of Scientific and Technical Information of China (English)

    张全虎; 隋洪志; 吕峰; 李泽

    2003-01-01

    线性衰减系数图像重建是层析γ扫描(TGS)的一个核心问题.本文从粒子输运方程出发,应用Monte-Carlo方法,提出了一种基于Monte-Carlo方法的统计迭代图像重建算法.模拟结果表明,与一般TGS图像重建算法相比,该重建算法的重建图像误差大为减小,能够满足TGS装置的要求.

  13. Stochastic simulation and Monte-Carlo methods; Simulation stochastique et methodes de Monte-Carlo

    Energy Technology Data Exchange (ETDEWEB)

    Graham, C. [Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France); Ecole Polytechnique, 91 - Palaiseau (France); Talay, D. [Institut National de Recherche en Informatique et en Automatique (INRIA), 78 - Le Chesnay (France); Ecole Polytechnique, 91 - Palaiseau (France)

    2011-07-01

    This book presents some numerical probabilistic methods of simulation with their convergence speed. It combines mathematical precision and numerical developments, each proposed method belonging to a precise theoretical context developed in a rigorous and self-sufficient manner. After some recalls about the big numbers law and the basics of probabilistic simulation, the authors introduce the martingales and their main properties. Then, they develop a chapter on non-asymptotic estimations of Monte-Carlo method errors. This chapter gives a recall of the central limit theorem and precises its convergence speed. It introduces the Log-Sobolev and concentration inequalities, about which the study has greatly developed during the last years. This chapter ends with some variance reduction techniques. In order to demonstrate in a rigorous way the simulation results of stochastic processes, the authors introduce the basic notions of probabilities and of stochastic calculus, in particular the essential basics of Ito calculus, adapted to each numerical method proposed. They successively study the construction and important properties of the Poisson process, of the jump and deterministic Markov processes (linked to transport equations), and of the solutions of stochastic differential equations. Numerical methods are then developed and the convergence speed results of algorithms are rigorously demonstrated. In passing, the authors describe the probabilistic interpretation basics of the parabolic partial derivative equations. Non-trivial applications to real applied problems are also developed. (J.S.)

  14. Pseudopotentials for quantum-Monte-Carlo-calculations; Pseudopotentiale fuer Quanten-Monte-Carlo-Rechnungen

    Energy Technology Data Exchange (ETDEWEB)

    Burkatzki, Mark Thomas

    2008-07-01

    The author presents scalar-relativistic energy-consistent Hartree-Fock pseudopotentials for the main-group and 3d-transition-metal elements. The pseudopotentials do not exhibit a singularity at the nucleus and are therefore suitable for quantum Monte Carlo (QMC) calculations. The author demonstrates their transferability through extensive benchmark calculations of atomic excitation spectra as well as molecular properties. In particular, the author computes the vibrational frequencies and binding energies of 26 first- and second-row diatomic molecules using post Hartree-Fock methods, finding excellent agreement with the corresponding all-electron values. The author shows that the presented pseudopotentials give superior accuracy than other existing pseudopotentials constructed specifically for QMC. The localization error and the efficiency in QMC are discussed. The author also presents QMC calculations for selected atomic and diatomic 3d-transitionmetal systems. Finally, valence basis sets of different sizes (VnZ with n=D,T,Q,5 for 1st and 2nd row; with n=D,T for 3rd to 5th row; with n=D,T,Q for the 3d transition metals) optimized for the pseudopotentials are presented. (orig.)

  15. Time management for Monte-Carlo tree search in Go

    NARCIS (Netherlands)

    Baier, Hendrik; Winands, Mark H M

    2012-01-01

    The dominant approach for programs playing the game of Go is nowadays Monte-Carlo Tree Search (MCTS). While MCTS allows for fine-grained time control, little has been published on time management for MCTS programs under tournament conditions. This paper investigates the effects that various time-man

  16. Testing Dependent Correlations with Nonoverlapping Variables: A Monte Carlo Simulation

    Science.gov (United States)

    Silver, N. Clayton; Hittner, James B.; May, Kim

    2004-01-01

    The authors conducted a Monte Carlo simulation of 4 test statistics or comparing dependent correlations with no variables in common. Empirical Type 1 error rates and power estimates were determined for K. Pearson and L. N. G. Filon's (1898) z, O. J. Dunn and V. A. Clark's (1969) z, J. H. Steiger's (1980) original modification of Dunn and Clark's…

  17. Plasma physics code contribution to the Mont-Blanc project

    OpenAIRE

    Sáez, Xavier; Soba, Alejandro; Mantsinen, Mervi

    2015-01-01

    This work develops strategies for adapting a particle-in-cell code to heterogeneous computer architectures and, in particular, to an ARM-based prototype of the Mont-Blanc project using OmpSs programming model and the OpenMP and OpenCL languages.

  18. A Variational Monte Carlo Approach to Atomic Structure

    Science.gov (United States)

    Davis, Stephen L.

    2007-01-01

    The practicality and usefulness of variational Monte Carlo calculations to atomic structure are demonstrated. It is found to succeed in quantitatively illustrating electron shielding, effective nuclear charge, l-dependence of the orbital energies, and singlet-tripetenergy splitting and ionization energy trends in atomic structure theory.

  19. Nanoporous gold formation by dealloying : A Metropolis Monte Carlo study

    NARCIS (Netherlands)

    Zinchenko, O.; De Raedt, H. A.; Detsi, E.; Onck, P. R.; De Hosson, J. T. M.

    2013-01-01

    A Metropolis Monte Carlo study of the dealloying mechanism leading to the formation of nanoporous gold is presented. A simple lattice-gas model for gold, silver and acid particles, vacancies and products of chemical reactions is adopted. The influence of temperature, concentration and lattice defect

  20. Auxiliary-field quantum Monte Carlo methods in nuclei

    CERN Document Server

    Alhassid, Y

    2016-01-01

    Auxiliary-field quantum Monte Carlo methods enable the calculation of thermal and ground state properties of correlated quantum many-body systems in model spaces that are many orders of magnitude larger than those that can be treated by conventional diagonalization methods. We review recent developments and applications of these methods in nuclei using the framework of the configuration-interaction shell model.

  1. Bayesian Monte Carlo Method for Nuclear Data Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Koning, A.J., E-mail: koning@nrg.eu

    2015-01-15

    A Bayesian Monte Carlo method is outlined which allows a systematic evaluation of nuclear reactions using TALYS. The result will be either an EXFOR-weighted covariance matrix or a collection of random files, each accompanied by an experiment based weight.

  2. Data libraries as a collaborative tool across Monte Carlo codes

    CERN Document Server

    Augelli, Mauro; Han, Mincheol; Hauf, Steffen; Kim, Chan-Hyeung; Kuster, Markus; Pia, Maria Grazia; Quintieri, Lina; Saracco, Paolo; Seo, Hee; Sudhakar, Manju; Eidenspointner, Georg; Zoglauer, Andreas

    2010-01-01

    The role of data libraries in Monte Carlo simulation is discussed. A number of data libraries currently in preparation are reviewed; their data are critically examined with respect to the state-of-the-art in the respective fields. Extensive tests with respect to experimental data have been performed for the validation of their content.

  3. Effective quantum Monte Carlo algorithm for modeling strongly correlated systems

    NARCIS (Netherlands)

    Kashurnikov, V. A.; Krasavin, A. V.

    2007-01-01

    A new effective Monte Carlo algorithm based on principles of continuous time is presented. It allows calculating, in an arbitrary discrete basis, thermodynamic quantities and linear response of mixed boson-fermion, spin-boson, and other strongly correlated systems which admit no analytic description

  4. A Monte Carlo Evaluation of Maximum Likelihood Multidimensional Scaling Methods

    NARCIS (Netherlands)

    Bijmolt, T.H.A.; Wedel, M.

    1996-01-01

    We compare three alternative Maximum Likelihood Multidimensional Scaling methods for pairwise dissimilarity ratings, namely MULTISCALE, MAXSCAL, and PROSCAL in a Monte Carlo study.The three MLMDS methods recover the true con gurations very well.The recovery of the true dimensionality depends on the

  5. Monte Carlo Simulation on Glueball Search at BESⅢ

    Institute of Scientific and Technical Information of China (English)

    QIN Hu; SHEN Xiao-Yan

    2007-01-01

    The J/ψ radiative decays are suggested as promising modes for glueball search. A full Monte Carlo simulation of J/ψ→γηη and γηη', based on the design of BESⅢ detector, is performed to study the sensitivity of searching for a possible tensor glueball at BESⅢ.

  6. Quantum Monte Carlo simulation of topological phase transitions

    Science.gov (United States)

    Yamamoto, Arata; Kimura, Taro

    2016-12-01

    We study the electron-electron interaction effects on topological phase transitions by the ab initio quantum Monte Carlo simulation. We analyze two-dimensional class A topological insulators and three-dimensional Weyl semimetals with the long-range Coulomb interaction. The direct computation of the Chern number shows the electron-electron interaction modifies or extinguishes topological phase transitions.

  7. Monte Carlo Simulation Optimizing Design of Grid Ionization Chamber

    Institute of Scientific and Technical Information of China (English)

    ZHENG; Yu-lai; WANG; Qiang; YANG; Lu

    2013-01-01

    The grid ionization chamber detector is often used for measuring charged particles.Based on Monte Carlo simulation method,the energy loss distribution and electron ion pairs of alpha particle with different energy have been calculated to determine suitable filling gas in the ionization chamber filled with

  8. Monte Carlo method for magnetic impurities in metals

    Science.gov (United States)

    Hirsch, J. E.; Fye, R. M.

    1986-01-01

    The paper discusses a Monte Carlo algorithm to study properties of dilute magnetic alloys; the method can treat a small number of magnetic impurities interacting wiith the conduction electrons in a metal. Results for the susceptibility of a single Anderson impurity in the symmetric case show the expected universal behavior at low temperatures. Some results for two Anderson impurities are also discussed.

  9. Improved Monte Carlo model for multiple scattering calculations

    Institute of Scientific and Technical Information of China (English)

    Weiwei Cai; Lin Ma

    2012-01-01

    The coupling between the Monte Carlo (MC) method and geometrical optics to improve accuracy is investigated.The results obtained show improved agreement with previous experimental data,demonstrating that the MC method,when coupled with simple geometrical optics,can simulate multiple scattering with enhanced fidelity.

  10. Simulating Strongly Correlated Electron Systems with Hybrid Monte Carlo

    Institute of Scientific and Technical Information of China (English)

    LIU Chuan

    2000-01-01

    Using the path integral representation, the Hubbard and the periodic Anderson model on D-dimensional cubic lattice are transformed into field theories of fermions in D + 1 dimensions. These theories at half-filling possess a positive definite real symmetry fermion matrix and can be simulated using the hybrid Monte Carlo method.

  11. Research of Monte Carlo Simulation in Commercial Bank Risk Management

    Institute of Scientific and Technical Information of China (English)

    BeimingXiao

    2004-01-01

    Simulation method is an important-tool in financial risk management. It can simulate financial variable or economic wriable and deal with non-linear or non-nominal issue. This paper analyzes the usage of "Monte Carlo" approach in commercial bank risk management.

  12. Observations on variational and projector Monte Carlo methods.

    Science.gov (United States)

    Umrigar, C J

    2015-10-28

    Variational Monte Carlo and various projector Monte Carlo (PMC) methods are presented in a unified manner. Similarities and differences between the methods and choices made in designing the methods are discussed. Both methods where the Monte Carlo walk is performed in a discrete space and methods where it is performed in a continuous space are considered. It is pointed out that the usual prescription for importance sampling may not be advantageous depending on the particular quantum Monte Carlo method used and the observables of interest, so alternate prescriptions are presented. The nature of the sign problem is discussed for various versions of PMC methods. A prescription for an exact PMC method in real space, i.e., a method that does not make a fixed-node or similar approximation and does not have a finite basis error, is presented. This method is likely to be practical for systems with a small number of electrons. Approximate PMC methods that are applicable to larger systems and go beyond the fixed-node approximation are also discussed.

  13. Monte-carlo calculations for some problems of quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Novoselov, A. A., E-mail: novoselov@goa.bog.msu.ru; Pavlovsky, O. V.; Ulybyshev, M. V. [Moscow State University (Russian Federation)

    2012-09-15

    The Monte-Carlo technique for the calculations of functional integral in two one-dimensional quantum-mechanical problems had been applied. The energies of the bound states in some potential wells were obtained using this method. Also some peculiarities in the calculation of the kinetic energy in the ground state had been studied.

  14. Play It Again: Teaching Statistics with Monte Carlo Simulation

    Science.gov (United States)

    Sigal, Matthew J.; Chalmers, R. Philip

    2016-01-01

    Monte Carlo simulations (MCSs) provide important information about statistical phenomena that would be impossible to assess otherwise. This article introduces MCS methods and their applications to research and statistical pedagogy using a novel software package for the R Project for Statistical Computing constructed to lessen the often steep…

  15. An Overview of the Monte Carlo Methods, Codes, & Applications Group

    Energy Technology Data Exchange (ETDEWEB)

    Trahan, Travis John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-08-30

    This report sketches the work of the Group to deliver first-principle Monte Carlo methods, production quality codes, and radiation transport-based computational and experimental assessments using the codes MCNP and MCATK for such applications as criticality safety, non-proliferation, nuclear energy, nuclear threat reduction and response, radiation detection and measurement, radiation health protection, and stockpile stewardship.

  16. Exact Dynamics via Poisson Process: a unifying Monte Carlo paradigm

    Science.gov (United States)

    Gubernatis, James

    2014-03-01

    A common computational task is solving a set of ordinary differential equations (o.d.e.'s). A little known theorem says that the solution of any set of o.d.e.'s is exactly solved by the expectation value over a set of arbitary Poisson processes of a particular function of the elements of the matrix that defines the o.d.e.'s. The theorem thus provides a new starting point to develop real and imaginary-time continous-time solvers for quantum Monte Carlo algorithms, and several simple observations enable various quantum Monte Carlo techniques and variance reduction methods to transfer to a new context. I will state the theorem, note a transformation to a very simple computational scheme, and illustrate the use of some techniques from the directed-loop algorithm in context of the wavefunction Monte Carlo method that is used to solve the Lindblad master equation for the dynamics of open quantum systems. I will end by noting that as the theorem does not depend on the source of the o.d.e.'s coming from quantum mechanics, it also enables the transfer of continuous-time methods from quantum Monte Carlo to the simulation of various classical equations of motion heretofore only solved deterministically.

  17. Quantum Monte Carlo simulation of topological phase transitions

    CERN Document Server

    Yamamoto, Arata

    2016-01-01

    We study the electron-electron interaction effects on topological phase transitions by the ab-initio quantum Monte Carlo simulation. We analyze two-dimensional class A topological insulators and three-dimensional Weyl semimetals with the long-range Coulomb interaction. The direct computation of the Chern number shows the electron-electron interaction modifies or extinguishes topological phase transitions.

  18. The Metropolis Monte Carlo Method in Statistical Physics

    Science.gov (United States)

    Landau, David P.

    2003-11-01

    A brief overview is given of some of the advances in statistical physics that have been made using the Metropolis Monte Carlo method. By complementing theory and experiment, these have increased our understanding of phase transitions and other phenomena in condensed matter systems. A brief description of a new method, commonly known as "Wang-Landau sampling," will also be presented.

  19. SPANDY: a Monte Carlo program for gas target scattering geometry

    Energy Technology Data Exchange (ETDEWEB)

    Jarmie, N.; Jett, J.H.; Niethammer, A.C.

    1977-02-01

    A Monte Carlo computer program is presented that simulates a two-slit gas target scattering geometry. The program is useful in estimating effects due to finite geometry and multiple scattering in the target foil. Details of the program are presented and experience with a specific example is discussed.

  20. Distributed and Adaptive Darting Monte Carlo through Regenerations

    NARCIS (Netherlands)

    Ahn, S.; Chen, Y.; Welling, M.

    2013-01-01

    Darting Monte Carlo (DMC) is a MCMC procedure designed to effectively mix between multiple modes of a probability distribution. We propose an adaptive and distributed version of this method by using regenerations. This allows us to run multiple chains in parallel and adapt the shape of the jump regi