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Sample records for abordaje coronal estudio

  1. Abordaje de un mal rendimiento académico en estudiante universitaria: Estudio de caso único

    OpenAIRE

    González Segura, B.; García León, A.

    2011-01-01

    El mal rendimiento académico es un problema ampliamente extendido entre la población universitaria y uno de los problemas más habituales junto a aquellos relacionados con la ansiedad y las técnicas de estudio. En el Gabinete de Psicología de la Universidad de Jaén tratamos a una estudiante cuyo motivo de consulta es la ansiedad ante los exámenes y el mal rendimiento. En relación a ello, se le aplican diferentes pruebas de evaluación: autorresgistro de hábitos de estudio diseñad...

  2. Estudios sobre periodismo digital: ejes principales que guiaron el abordaje de la digitalización de las noticias

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    Juan Pablo Hamada

    2013-04-01

    Full Text Available Los trabajos enfocados en estudiar los procesos de digitalización de las noticias ya no constituyen un tema incipiente en el campo de la comunicación. Pasaron más de 15 años de la aparición de los primeros formatos online de los periódicos y ya es posible encontrar diversos tipos de abordajes académicos que dan cuenta de preocupaciones teóricas y metodológicas sobre los modos de abordar los procesos de digitalización de las noticias. En el siguiente trabajo presentaremos una síntesis de los principales aportes realizados en Iberoamérica y Estados Unidos con el objeto agrupar 3 matrices que en general han guiado a los intereses de estos trabajos: a relevar las primeras experiencias de digitalización de periódicos ya reconocidos, b analizar las nuevas características que asume la práctica periodística y los componentes discursivos de los nuevos formatos periodísticos y c reconocer la emergencia de nuevos actores que comienzan a disputar el campo periodístico.

  3. El Proyecto MADAI: Un estudio epidemiológico sobre el abordaje y manejo del dolor agudo periquirúrgico MADAI project: an epidemiologic study about the perioperative pain management and treatment

    OpenAIRE

    J. L. Balibrea; F. López-Timoneda; F. Acín; Cabero, L; A. Moreno-González; L. E. Ayala

    2008-01-01

    Objetivo. Obtener información descriptiva sobre el abordaje y el manejo del paciente con dolor agudo periquirúrgico tratado con analgésicos parenterales en el ámbito hospitalario. Metodología. Estudio epidemiológico, descriptivo, multicéntrico. Pacientes ingresados en los servicios de cirugía general, torácica, cardiovascular, angiología y cirugía vascular, ginecología, traumatología y urología. Resultados. Participaron 76 hospitales distribuidos por las diferentes comunidades autónomas y un ...

  4. Influencia de los abordajes craneomandibular y cervical sobre los desórdenes temporomandibulares en el latigazo cervical: estudio de caso

    OpenAIRE

    Sánchez Robledo, Alejandra

    2016-01-01

    Introducción: Muchos autores evidencian la relación entre desórdenes temporomandibulares (DTM) y latigazo cervical. Concluyen que su fisiopatología es más compleja que en DTM sin antecedente traumático, perpetuando los síntomas y dificultando la respuesta al tratamiento. Son pocos los protocolos que incluyen un abordaje de ATM tras whiplash o estudian los efectos de diversos abordajes ante esta patología. Objetivos: Identificar la efectividad de diferentes estrategias terapéuticas ante pat...

  5. LA HERMENEUTICA COMO UNA PROPUESTA METODOLOGICA PARA EL ABORDAJE DE ESTUDIOS INTERCULTURALES: EL CASO DE LA CULTURAEN RELACION A LAS TORTUGAS

    Directory of Open Access Journals (Sweden)

    Oscar Fernando Camacho Tamayo

    2014-05-01

    Full Text Available La hermenéutica es una propuesta metodológica en la cual la comprensión de la realidad social se asume bajo la metáfora de un texto, el cual es susceptible de ser interpretado. El objetivo de este artículo consiste en ejemplarizar el desarrollo metodológico del enfoque hermenéutico a partir dela investigaciónCultura y Tortugas, los niños hablan acerca de la Tortuga (P. expansa, la Terecay (P. unifilis y conservación (Camacho, 2012. Esta propuesta metodológica, según Sandoval (1993  comprende el análisis de dos construcciones esenciales, el Pre-Texto y el Texto. El primer apartado tiene en cuenta el conjunto de conceptos que fundamenta teóricamente el trabajo de investigación, además de la información concerniente al contexto de la zona de estudio. Mientras que el Texto corresponde a la estructuración sistemática de los resultados obtenidos a partir del uso de las diversas estrategias de investigación, como por ejemplo las entrevistas, las encuestas y otras charlas informales.  Desde esta perspectiva, el trabajo consistía en recuperar la información acerca de las Tortugas y comenzarlas a relacionar con los conocimientos ancestrales. Para ello se tuvo en cuenta un proceso que se conoce como codificación, que consiste en “generar conceptos a partir de nuestros datos y usar códigos como manera de lograrlo” (Coffeyet al, 2003.Ello exige un proceso de investigación arduo, que va desde la recopilación de información, su posterior transcripción, la codificación de estos y por último el análisis, la comprensión e interpretación de los resultados obtenidos.

  6. Abordaje de la tuberculosis en Atención Primaria. Estudio de contactos Dealing with tuberculosis in primary care. Contact tracing procedures

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    F. Teruel

    2007-01-01

    Full Text Available Aunque el número de casos de tuberculosis en Navarra ha descendido en los últimos años, resulta necesario adaptar los programas de control a la nueva situación. Las claves para avanzar en su prevención y control son: conseguir un diagnóstico precoz y un tratamiento efectivo de los enfermos y detectar y tratar a las personas con infección latente. En ambas actividades la atención primaria juega un importante papel. La mitad de los casos de tuberculosis activa que se diagnostican han sido contactos de enfermos bacilíferos o bien tenían una elevada predisposición personal de desarrollar la enfermedad. Por ello la detección y tratamiento de la infección latente en nuestro medio se debe realizar: 1. Mediante cribado en personas con alto riesgo de infectarse y desarrollar enfermedad, y 2. Fundamentalmente en el estudio sistemático de contactos de los casos con enfermedad. En el tratamiento, tanto de la tuberculosis activa como de la infección latente, es imprescindible conseguir un buen cumplimiento del paciente.Although the number of cases of tuberculosis in Navarre has fallen in recent years, it is necessary to adapt the control programs to the new situation. The keys to advancing in its prevention and control are: obtaining an early diagnosis and an effective treatment of patients and detecting and treating people with a latent infection. Primary care plays an important role in both activities. Half of the cases of active tuberculosis that are diagnosed have been contacts by bacilliferous TB patients or else have had a high personal predisposition to developing the disease. That is why detection and treatment of the latent infection in our setting must be carried out: 1 through screening persons at high risk of becoming infected and developing the disease, and 2 trough a systematic study of contacts of persons with the disease. In the treatment of both active tuberculosis and latent infection it is essential to obtain good patient

  7. Capacidad de sellado inmediato y a distancia de distintos materiales de obturación coronal. Estudio in vitro.

    OpenAIRE

    Pascualini, Carlos José

    2014-01-01

    Con el propósito de estudiar in vitro la capacidad de sellado que poseen distintos materiales utilizados como obturación temporal en dientes tratados endodónticamente, se efectuó mediante un método bacteriológico, un primer estudio. Para ello se seleccionaron 78 premolares recientemente extraídos con pulpa vital sana o levemente inflamada. A todos ellos se les seccionó parte de la raíz, dejando un remanente de 5mm. Luego, con alta velocidad, r...

  8. Abordaje a la Cisterna Ambiens

    Science.gov (United States)

    Ajler, Pablo; Bravo, Michael Cruz; Garategui, Lucas; Goldschmidt, Ezequiel; Isolan, Gustavo; Campero, Álvaro

    2016-01-01

    Resumen Objetivo: Describir paso a paso el abordaje a la cisterna ambiens por la vía suboccipital retrosigmoidea supracerebelosa infratentorial (SRSI). Descripción: El abordaje SRSI se realiza de la misma manera que el abordaje suboccipital retrosigmoideo (SR), utilizado habitualmente para acceder a la patología del ángulo pontocerebeloso, con las siguientes modificaciones: (1) utilizamos siempre la posición semisentado, (2) la craneotomia-craniectomia debe exponer el seno transverso y extenderse 5 cm medialmente hacia el inion, (3) al realizar la apertura dural es necesario rebatir la duramadre junto con el seno transverso hacia cefálico con puntos de tracción, (4) bajo magnificación con microscopio quirúrgico se debe realizar la apertura de la cisterna cerebelobulbar para drenar líquido cefalorraquídeo, (5) en el plano supracerebeloso es fundamental cortar las bridas aracnoidales y de ser necesario debemos coagular y cortar las venas puente, todas estas maniobras sumadas al efecto de la gravedad brindan mayor apertura del corredor supracerebeloso. Conclusión: El abordaje a la cisterna ambiens por la vía SRSI es una opción segura para el acceso de patologías tumorales que se alojan en esta zona con un componente predominantemente infratentorial. PMID:27999709

  9. Coronal dynamics

    Science.gov (United States)

    Nakariakov, V. M.

    2007-07-01

    The lectures present the foundation of solar coronal physics with the main emphasis on the MHD theory and on wave and oscillatory phenomena. We discuss major challenges of the modern coronal physics; the main plasma structures observed in the corona and the conditions for their equilibrium; phenomenology of large scale long period oscillatory coronal phenomena and their theoretical modelling as MHD waves. The possibility of the remote diagnostics of coronal plasmas with the use of MHD oscillations is demonstrated.

  10. Los estudios de policía en Latinoamérica. Algunas limitaciones teóricas y metodológicas en su abordaje como objeto directo

    Directory of Open Access Journals (Sweden)

    Juan Aparicio Barrera

    2016-12-01

    Full Text Available El artículo responde a la pregunta: ¿Por qué son tan pocos los estudios sobre los cuerpos de policía en Latinoamérica? Este déficit histórico en parte se debe a que los estudios sobre la policía se han ligado por la academia latinoamericana a la teoría del Estado de clase, al derecho administrativo, a los estudios de las Fuerzas Militares y más recientemente al neoinstitucionalismo; sumado a ello, a la ausencia de interés de las mismas instituciones policiales por realizar estudios sociales. El objetivo principal fue realizar un estado del arte sobre los estudios de policía en Latinoamérica. En conclusión, se señala que la policía no se ha estudiado como un objeto autónomo. Tan solo desde la década de los 90 del siglo XX, bajo el contexto de las transiciones democráticas, existe un renovado interés por estudiar a los cuerpos de policía.

  11. Analizando la invisibilización del ambiente. La danza y el movimiento como abordaje metodológico en estudios de sensibilidad y percepción ambiental

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    Victoria D'hers

    2012-10-01

    Full Text Available Partiendo de lo observado en un estudio previo, referido como procesos de "invisibilización/silenciamiento" de las condiciones ambientales en las cuales los sujetos construyen cotidianamente sus vidas, se propone un estudio exploratorio de las posibilidades de aplicación de metodología cualitativa ligada a expresiones creativas y el movimiento.En primer término, se recorren las conclusiones previas, argumentando que en la población habitante de asentamientos precarios se da una superposición de sufrimientos fuertemente marcados por la necesidad, donde se ocluyen las referidas condiciones ambientales adversas presentes en barrios asentados sobre lo que fueran basurales a cielo abierto.Luego, se propone la aplicación de metodologías basadas en la expresividad y la creatividad en el movimiento, tanto en la generación de datos como en la apertura para ex-presar aquello invisibilizado −poniendo en juego el sentido práctico de los sujetos−, como en su posterior análisis e interpretación hacia la comprensión de las sensibilidades sociales. En esta línea se presentan las primeras indagaciones a nivel de las preguntas básicas planteadas por estos objetivos, un breve estado del arte en estudios de este tipo y los desafíos que se plantean

  12. Cine y estudios de género: Imagen, representación e ideología. Notas para un abordaje crítico Cinema and gender studies: Image, representation and ideology. Notes for a critical approach

    OpenAIRE

    Paula Laguarda

    2006-01-01

    El cine, en tanto productor de imágenes, representaciones, significados e ideologías, aparece como un terreno óptimo para el rastreo del modo en que se han construido las subjetividades, desde la popularización de esta técnica en las primeras décadas del siglo XX hasta la actualidad. En este sentido ofrece a los estudios de género una fuente de primer orden para el análisis de las representaciones socialmente dominantes acerca de lo femenino y lo masculino y las características asignadas a ca...

  13. El desguante craneorbitofacial como abordaje craneofacial y sus aplicaciones clínicas

    OpenAIRE

    Rubén Muñoz; Jose Golaszewski; Alvaro Díaz

    2012-01-01

    El propósito de este estudio es describir la técnica quirúrgica para el abordaje del tercio superior y medio facial para cirugía craneofacial. Es un método de disección del macizo craneofacial que utiliza incisiones palpebrales tipo blefaroplastia, incisión bicoronal, incisión endonasal supracartilaginosa bilateral y dependiendo de las necesidades el Cirujano, abordajes preauriculares tipo Ritidectomía. La técnica está indicada en pacientes con múltiples fracturas cráneo-faciales y sus sec...

  14. Cine y estudios de género: Imagen, representación e ideología. Notas para un abordaje crítico Cinema and gender studies: Image, representation and ideology. Notes for a critical approach

    Directory of Open Access Journals (Sweden)

    Paula Laguarda

    2006-12-01

    Full Text Available El cine, en tanto productor de imágenes, representaciones, significados e ideologías, aparece como un terreno óptimo para el rastreo del modo en que se han construido las subjetividades, desde la popularización de esta técnica en las primeras décadas del siglo XX hasta la actualidad. En este sentido ofrece a los estudios de género una fuente de primer orden para el análisis de las representaciones socialmente dominantes acerca de lo femenino y lo masculino y las características asignadas a cada uno; así como la interacción de la categoría de género con otras como clase, etnicidad, nación, domesticidad, educación, ejercicio de la sexualidad y edad. En el artículo se abordan críticamente las principales líneas teóricas que han vinculado cine y feminismo y las posibilidades que éste ofrece a los estudios de género, al permitir la indagación simultánea sobre aspectos textuales (discursivos, narrativos y recursos propios del lenguaje cinematográfico y contextuales (al considerar al cine a la vez como industria cultural y manifestación de la cultura popular.Cinema, as a producer of images, representations, meanings and ideologies, seems to be an optimum territory for tracing the way in which subjectivities had been constructed, sinces the popularization of this technique on the early decades of XX century to the present day. In this sense, cinema provides gender studies with a source of prime order to analyse socially dominant representations about female and male, and the characteristics assigned to each other; such as the interaction between gender category and other like class, ethnicity, nation, domesticity, education, sexuality and age. This article approaches critically to the main theoretical lines that had conected cinema and feminism, and to the possibilities it offers to gender studies, by allowing simultaneous research on textual aspects (discoursive, narrative elements and resources of cinematographic language and

  15. A mulher japonesa vivenciando o câncer cérvico-uterino: um estudo de caso com abordagem da fenomenologia social La mujer japonesa vivenciando el cáncer cervico-uterino: un estudio del caso con abordaje fenomenológía social A japanese woman going through cervical uterine cancer: a case study with the social phenomenology approach

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    Rosa Yuka Sato Chubaci

    2005-06-01

    Full Text Available Trata-se de estudo sobre a experiência de uma mulher japonesa, com câncer cérvico-uterino, realizado em um hospital da cidade de Osaka-Japão, no qual se utilizou o "estudo de caso" com abordagem da Fenomenologia Social de Alfred Schütz. Objetivou-se conhecer o significado da doença e da hospitalização para essa mulher, buscando compreender os motivos que envolvem a sua ação. Por meio da análise dos dados, foi possível compreender que o processo da hospitalização deve ser visto respeitando, além da característica individual, o mundo cultural que nos remete às ações humanas e que exerce influência importante no comportamento e atitude em relação à doença e hospitalização.Se trata de un estudio sobre la experiencia de una mujer japonesa, con cáncer cérvico-uterino, realizado en un hospital de la ciudad de Osaka-Japón, en el cual se utilizó el "estudio de caso" con abordaje de la Fenomenología Social de Alfred Schütz. El objetivo fue conocer el significado de la enfermedad y de la hospitalización para esa mujer, buscando comprender los motivos que involucran su acción. Por medio del análisis de los datos, fue posible comprender que el proceso de la hospitalización debe ser visto respetan-do, además de la característica individual, el mundo cultural que nos remite a las acciones humanas y que ejerce influencia importante en el comportamiento y actitud en relación a la enfermedad y hospitalización.This is the study of the experience of a Japanese woman with cervical uterine cancer carried out in a hospital in the city of Osaka, Japan, using Alfred Schütz's "case study" with the Social Phenomenology approach. The aim was to grasp the meaning of the disease and of hospitalization for this woman, and to try to understand the reasoning around her action. Through the analysis of the data, it was possible to understand that the hospitalization process has to be seen respecting, in addition to individual

  16. Coronal magnetometry

    CERN Document Server

    Zhang, Jie; Bastian, Timothy

    2014-01-01

    This volume is a collection of research articles on the subject of the solar corona, and particularly, coronal magnetism. The book was motivated by the Workshop on Coronal Magnetism: Connecting Models to Data and the Corona to the Earth, which was held 21 - 23 May 2012 in Boulder, Colorado, USA. This workshop was attended by approximately 60 researchers. Articles from this meeting are contained in this topical issue, but the topical issue also contains contributions from researchers not present at the workshop. This volume is aimed at researchers and graduate students active in solar physics. Originally published in Solar Physics, Vol. 288, Issue 2, 2013 and Vol. 289, Issue 8, 2014.

  17. El Desguante craneorbitofacial como abordaje craneofacial y sus aplicaciones clínicas

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    Rubén Muñoz

    2012-09-01

    Full Text Available El propósito de este estudio es describir la técnica quirúrgica para el abordaje del tercio superior y medio facial para cirugía craneofacial. Es un método de disección del macizo craneofacial que utiliza incisiones palpebrales tipo blefaroplastia, incisión bicoronal, incisión endonasal supracartilaginosa bilateral y dependiendo de las necesidades el Cirujano, abordajes preauriculares tipo Ritidectomía. La técnica está indicada en pacientes con múltiples fracturas cráneo-faciales y sus secuelas, tumores craneofaciales benignos, malignos y corrección de deformidades craneofaciales. En el presente estudio se reporta dos casos de pacientes que asistieron al Servicio de Cirugia Bucal y Maxilofacial del Hospital Universitario "Dr Angel Larralde", presentado secuela de fractura frontal y Naso-órbito-etmoidal Tipo III, ambos con una evolución de 6 meses. Se decide su resolución mediante abordaje craneorbitofacial (The Dismasking Flap, reconstrucción del tercio superior y medio facial mediante material de  osteosíntesis, así como desfuncionalización del seno frontal y reconstrucción de la pared anterior. Como resultado, no se evidencio compromiso de la mímica facial ni de la sensibilidad. En conclusión el abordaje craniorbitofacial es una herramienta para el abordaje de fracturas craneofaciales, recontrucciones craneofaciales, resección de tumores de la fosa craneal anterior, cirugía microvascular y trasplante facial.

  18. Coronal Holes

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    Steven R. Cranmer

    2009-09-01

    Full Text Available Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations, and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are established in the extended corona. For example, the importance of kinetic plasma physics and turbulence in coronal holes has been affirmed by surprising measurements from the UVCS instrument on SOHO that heavy ions are heated to hundreds of times the temperatures of protons and electrons. These observations point to specific kinds of collisionless Alfvén wave damping (i.e., ion cyclotron resonance, but complete theoretical models do not yet exist. Despite our incomplete knowledge of the complex multi-scale plasma physics, however, much progress has been made toward the goal of understanding the mechanisms ultimately responsible for producing the observed properties of coronal holes.

  19. Abordagem holística do termo pessoa em um estudo empírico: uma análise crítica Abordaje holístico del término persona en un estudio empírico: un análisis crítico Holistic approach of the term "person" in an empirical study: a critical analysis

    Directory of Open Access Journals (Sweden)

    David Lopes Neto

    2002-12-01

    Full Text Available O estudo analisa a semântica e a estrutura do termo pessoa (mulheres com HIV, mediante abordagem holística fundamentada no Modelo de Adaptação de Roy (Veritivity e na fenomenologia de Heidegger (Dasein. Pesquisa extraída da literatura das Ciências Enfermagem e Filosofia, através da técnica de documentação indireta, com utilização do modelo de análise de teoria de Chinn & Kramer, através do qual foram analisados os seguintes aspectos: objetividade, simplicidade, generalidade, acessibilidade e importância dos conceitos de pessoa e holismo no estudo empírico "Nutritional adaptation of women living with HIV: a pilot study", publicado na revista Holistic Nursing Practice, em 1997. Criticamente, a interpretação do termo pessoa se deu pela compreensão do ser enquanto um ser ôntico-ontológico, como forma de percepção verdadeira do sentido do ser (pessoa, como uma estrutura universal vivente em um mundo antropológico e social, ao qual mulheres com HIV podem se adaptar ao novo estilo de vida e receber atenção integral da enfermagem, principalmente no que concerne ao aspecto nutricional.El estudio analiza la semántica y la estructura del término: persona (mujeres con HIV, mediante el abordaje holitico basado en el Modelo de Adaptación de Roy (Veritivity y en la fenomenología de Heidegger (Dasein. Investigación extraída de la literatura de las Ciencias de enfermería y filosofía, a través de la técnica de documentacion indirecta, con la utilización del modelo de análisis de teoria de Chinn & Kramer a través del cual se analizaron los siguientes aspectos: la objetividad, simplicidad, generalidad, accesibilidad y importancia de los conceptos de persona y holismo en el estudio empírico Nutritional adaptation of women living with HIV: a pilot study, publicado en la revista Holistic Nursing Practice, en 1997. Críticamente, la interpretación del término persona se dio por la comprensión de ser como ontico

  20. Coronal Holes

    CERN Document Server

    Cranmer, Steven R

    2009-01-01

    Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations), and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are establish...

  1. Assistência à criança com disfunção neuromotora na abordagem da rede social: um estudo de caso Asistencia al niño con disfunción neuromotora en el abordaje de la red social: un estudio de caso Assistance to the child with neuromotor disorder using a social networkapproach: a case study

    Directory of Open Access Journals (Sweden)

    Renata Dourado da Silveira

    2009-03-01

    Full Text Available O estudo de caso teve como propósito descrever a situação de saúde de uma criança com disfunção neuromotora e sua rede social, com aprofundamento no contexto socioeconômico. Os objetivos foram: identificar o cuidador da criança; construir o mapa da rede social da criança; discutir a importância do cuidador e contexto familiar no desenvolvimento da criança com disfunção neuromotora. Os dados foram coletados no prontuário na consulta de enfermagem; na abordagem da mãe durante a fisioterapia; na visita à casa da avó materna; na observação sistemática da criança, e mantiveram-se contatos pelo telefone. Os resultados mostraram que a menina está envolvida com diferentes pessoas e tem variados vínculos. Conclui-se que, apesar de a rede social ser ampla e densa, seus vínculos são fragilizados, o que torna a relação íntima e direta da menina restrita a poucas pessoas, como mãe, irmão e avó materna.El estudio de caso tuvo como propósito describir la situación de la salud de una niña con disfunción neuromotora y su red social, con profundización en el contexto socio-económico. Los objetivos fueron: identificar el cuidador de la niña; construir el mapa de la red social de la niña; discutir la importancia del cuidador y del contexto familiar en el desarrollo de la niña con disfunción neuromotora. Los datos fueron colectados en el registro médico; consulta de enfermería; abordaje de la madre durante la fisioterapia; visita a la casa de la abuela materna; observación sistemática de la niña y contactos por teléfono. Los resultados mostraron que la niña está enredada con diversas personas y variados enlaces. Se concluye aunque la red social sea amplia y densa, sus enlaces son fragilizados, lo que torna la relación íntima y directa a la niña restricta a pocas personas, como madre, hermano, abuela materna.The case study's intention was to describe the situation regarding the health of a child with neuromotor

  2. Abordaje subfrontal para el tratamiento de un estesioneuroblastoma

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    Alfonso Mogedas-Vegara

    2014-10-01

    La resección craneofacial, empleando un abordaje subfrontal, es uno de los abordajes de elección para el tratamiento de esta compleja entidad. Describimos un caso tratado en nuestra institución que fue resuelto favorablemente con este procedimiento, así como una revisión exhaustiva de la bibliografía con respecto a este tipo de tumor y a las ventajas de este abordaje.

  3. Tecnología de gráficos en computadora, enfoques subyacentes a su abordaje en carreras universitarias proyectuales

    Directory of Open Access Journals (Sweden)

    Balmaceda, María Isabel

    2015-12-01

    Full Text Available Existen múltiples teorías desde donde se puede entender y definir la tecnología. Cada una de ellas supone diferentes posicionamientos frente a la realidad, condiciona la definición de objetos de estudio y también las metodologías para su abordaje desde la educación. En este trabajo se analizan los posicionamientos que subyacen a tres modalidades diferentes en relación con el abordaje de la “tecnología de gráficos en computadora” (como parte del universo de la tecnología computacional, en carreras universitarias proyectuales. Se plantean las consecuencias de estos enfoques en la formación de los futuros profesionales y se fundamenta por qué se deberían generalizar modalidades que se sustenten en un enfoque crítico frente a la tecnología.

  4. Coronal influence on dynamos

    CERN Document Server

    Warnecke, Jörn

    2013-01-01

    We report on turbulent dynamo simulations in a spherical wedge with an outer coronal layer. We apply a two-layer model where the lower layer represents the convection zone and the upper layer the solar corona. This setup is used to study the coronal influence on the dynamo action beneath the surface. Increasing the radial coronal extent gradually to three times the solar radius and changing the magnetic Reynolds number, we find that dynamo action benefits from the additional coronal extent in terms of higher magnetic energy in the saturated stage. The flux of magnetic helicity can play an important role in this context.

  5. Abordaje farmacoterapéutico del paciente hospitalizado con desórdenes hiperglucémicos

    OpenAIRE

    Chaverri Fernández, José Miguel; Cordero García, Eugenia; Fallas Retana, Fallom; Montoya Calderón, Vivian; Zavaleta Monestel, Esteban

    2014-01-01

    Justificación y Objetivo: Los desórdenes glucémicos están asociados a una mayor morbimortalidad en el ámbito hospitalario. El conocer la realidad actual y describir los modelos de abordaje farmacoterapéutico de los desórdenes glucémicos facilita la implementación de guías clínicas que promuevan el correcto uso de medicamentos. Material y métodos: Se propuso con este fin realizar un estudio observacional retrospectivo, que incluyera a los pacientes hospitalizados en el Hospital Clínica Bíblica...

  6. Abordaje de la disfagia en enfermos de alzhéimer

    Directory of Open Access Journals (Sweden)

    Marta Baena González

    Full Text Available Introducción: la disfagia es un síntoma que se refiere a la dificultad para mover el bolo alimentario desde la boca al estómago. A pesar de su relevancia y de la gravedad de sus posibles complicaciones, es poco conocida y estudiada. La prevalencia de la disfagia orofaríngea en enfermos de alzhéimer es de un 84% y puede originar complicaciones de gran trascendencia clínica como consecuencia de las alteraciones en la eficacia de la deglución, y en la seguridad de la misma. Objetivo: conocer el estado actual del conocimiento en relación al abordaje de la disfagia en enfermos de alzhéimer, localizando aquellos factores que permitan un diagnóstico precoz que facilite la prevención de complicaciones y la elección de la pauta de actuación más adecuada. Metodología: revisión sistemática. Estudios publicados entre 2005 y 2014 en inglés y castellano. Bases de datos: PubMed, Cochrane, Scopus, Elsevier, Scielo y Dialnet. Términos MeSH empleados: disfagia, dysphagia, alzheimer, modified y texture food. Resultados: el diagnóstico en los pacientes de alzhéimer se realiza mediante métodos clínicos y exploraciones complementarias como la videofluoroscopia, considerada como el estándar para el estudio de la disfagia orofaríngea, ya que permite identificar entre 1/3 y 1/4 de los pacientes que presentan aspiraciones silentes no diagnosticables clínicamente. Existen estrategias terapéuticas que incluyen cambios en el volumen y viscosidad del bolo, cambios posturales, maniobras deglutorias, procedimientos de rehabilitación y técnicas de incremento sensorial que han demostrado su eficacia, pero se trata de una labor compleja que exige un abordaje multidisciplinar para un correcto diagnóstico y tratamiento. Conclusiones: existe una escasa evidencia científica en el abordaje de la disfagia y un gran desconocimiento en cuanto a la alimentación de los enfermos de alzhéimer. Esta patología necesita una intervención multidisciplinar en la

  7. Modelo de estudio de dos informativas familias colombianas con Síndrome de Usher

    Directory of Open Access Journals (Sweden)

    Tamayo ML.

    2001-06-01

    Full Text Available Establecer y evaluar un modelo de abordaje para el estudio del Síndrome de Usher, que abarca el diagnóstico clínico de los pacientes, establecimiento y confirmación del subtipo mediante estudios moleculares y posterior correlación genotipo-fenotipo.

  8. Coronal Waves and Oscillations

    Directory of Open Access Journals (Sweden)

    Nakariakov Valery M.

    2005-07-01

    Full Text Available Wave and oscillatory activity of the solar corona is confidently observed with modern imaging and spectral instruments in the visible light, EUV, X-ray and radio bands, and interpreted in terms of magnetohydrodynamic (MHD wave theory. The review reflects the current trends in the observational study of coronal waves and oscillations (standing kink, sausage and longitudinal modes, propagating slow waves and fast wave trains, the search for torsional waves, theoretical modelling of interaction of MHD waves with plasma structures, and implementation of the theoretical results for the mode identification. Also the use of MHD waves for remote diagnostics of coronal plasma - MHD coronal seismology - is discussed and the applicability of this method for the estimation of coronal magnetic field, transport coefficients, fine structuring and heating function is demonstrated.

  9. Coronal Mass Ejections

    Science.gov (United States)

    Crooker, Nancy; Joselyn, Jo Ann; Feynman, Joan

    The early 1970's can be said to mark the beginning of The Enlightenment in the history of the Space Age, literally as well as by analogy to European history. Instruments blinded by Earth's atmosphere were lifted above and, for the first time, saw clearly and continuously the ethereal white light and sparkling x-rays from the solar corona. From these two bands of the light spectrum came images of coronal mass ejections and coronal holes, respectively. But whereas coronal holes were immediately identified as the source of high-speed solar wind streams, at first coronal mass ejections were greeted only by a sense of wonder. It took years of research to identify their signatures in the solar wind before the fastest ones could be identified with the well-known shock disturbances that cause the most violent space storms.

  10. Mechanisms of Coronal Heating

    Indian Academy of Sciences (India)

    S. R. Verma

    2006-06-01

    The Sun is a mysterious star. The high temperature of the chromosphere and corona present one of the most puzzling problems of solar physics. Observations show that the solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in solar corona. Recent observations show that Magnetic Carpet is a potential candidate for solar coronal heating.

  11. Approach-related morbidity in transthoracic anterior spine surgery: a clinical study and review of literature Morbilidad relacionada con el abordaje torácico anterior de la columna: estudio clínico y revisión de la literatura Morbidade relacionada à abordagem transtorácica anterior da coluna: estudo clínico e revisão da literatura

    Directory of Open Access Journals (Sweden)

    Juliane Zenner

    2010-03-01

    presente estudio fue observar los resultados relacionados con la morbilidad de la toracotomía abierta para la corrección de la deformidad de la columna vertebral y toracotomía para la colocación de tubo de drenaje torácica, utilizando ese grupo como Control. MÉTODOS: con base en un cuestionario respondido por los pacientes; y relacionado con la evaluación de la morbilidad del abordaje anterior de la columna torácica y utilizando criterios estrictos de inclusión de los pacientes, fueron evaluados 43 pacientes sometidos a toracotomía abierta para tratamiento de la escoliosis; y 30 pacientes portadores de otras enfermedades de menor gravedad, que fueron sometidos a la toracotomía para la colocación de dreno de tórax después del procedimiento. RESULTADOS: el promedio de edad de los pacientes sometidos al procedimiento en el tórax y a la toracotomía para la colocación de dreno o toracotomía abierta para tratamiento de escoliosis fue, respectivamente: 50.2 años y 16.5 años; el seguimiento clínico fue de 32.2 meses y 54.8 meses; y la extensión de la incisión de la piel 2.5 cm y 25 cm. El promedio del número de vértebras artrosadas fue 5.8 en el grupo sometido a la toracotomía abierta para la corrección de deformidad. La morbilidad promedio (variando de 0% - ninguna morbilidad a 100% - alta morbilidad en el grupo de pacientes sometidos a la toracotomía para colocación de dreno de tórax fue de 10.8±15.4 (0-59.5%, y un 42% de los pacientes no presentaron morbilidad. En el grupo sometido a la toracotomía abierta para la colocación del dreno de tórax fue observada neuralgia intercostal en 16.7%, y 35% de los pacientes presentaron morbilidad mayor que 10% (pormedio de un 27.5%. La morbilidad fue definida como la presencia de dolor crónico después de la toracotomía. En el grupo sometido a la toracotomía abierta para tratamiento de escoliosis el promedio de la morbilidad fue 7.0±12.7% (0-52.1%, y 44% no presentaron morbilidad. Señales de neuralgia

  12. Estudo sobre os elementos de uma interpretação invasiva na abordagem psicanalítica winnicottiana Estudio sobre los elementos de una interpretación invasiva en el abordaje psicoanalítico winnicottiano Study on the elements of an invasive interpretation in the Winnicott psychoanalytical approach

    Directory of Open Access Journals (Sweden)

    Conceição Aparecida Serralha

    2012-04-01

    Full Text Available Partindo dos textos freudianos, este estudo reapresenta brevemente a técnica da interpretação em psicanálise e, baseando-se na obra de Winnicott, discute os elementos de uma interpretação sentida de forma invasiva pelo analisando. São identificados, nomeados e discutidos os elementos apontados por este autor: tempo, modo, graus de confiabilidade, objetividade e conhecimento, sendo ilustrados por alguns fragmentos de sessão de casos de Winnicott e de um caso da autora. O estudo evidencia a importância da capacidade de o analista se identificar com o analisando para interpretar, recebendo e entendendo a comunicação deste sobre a adequação de todos esses elementos ao seu caso.Partiendo de los textos freudianos, este estudio reapresenta brevemente la técnica de la interpretación en psicoanálisis y, basándose en la obra de Winnicott, discute los elementos de una interpretación sentida de forma invasiva por el analizando. Son identificados, nombrados y discutidos los elementos apuntados por este autor: tiempo, modo, grados de confiabilidad, objetividad y conocimiento, siendo ilustrados por algunos fragmentos de sesión de casos de Winnicott y de un caso de lo autor. El estudio evidencia la importancia de la capacidad de el analista identificarse con el analizando para interpretar, recibiendo y entendiendo la comunicación de este sobre la adecuación de todos esos elementos a su caso.From the Freudian texts, this study reintroduces briefly the technique of interpretation in psychoanalysis and, based on the Winnicott's works, discusses the elements of an interpretation felt invasive by the patient. The elements pointed out by this author and identified, named and discussed include: time, manner, degrees of trustworthiness, objectiveness and knowledge. They are illustrated with fragments of session of Winnicott's cases and one case of the author. The study highlights the importance of the analyst's capacity of identifying him

  13. Braquioplastia: abordaje simple Braquioplastias: Uma abordagem simplificada Brachioplasty: a simple aproach

    Directory of Open Access Journals (Sweden)

    C. Roxo del Pino

    2009-09-01

    Full Text Available Los miembros superiores representan una unidad estético- funcional muy importante en la definición del contorno corporal. Con la popularización de las cirugía de remodelación del contorno corporal tras grandes pérdidas ponderales también se ha producido un incremento en la práctica de braquioplastias. El propósito de nuestra trabajo es el mostrar nuestra experiencia en braquioplastia enfocada hacia la simplificación del abordaje quirúrgico para lograr corregir la flacidez de la zona póstero-inferior de los brazos. Presentamos un estudio retrospectivo sobre 22 pacientes sometidas a braquioplastia mediante la técnica de abordaje quirúrgico propuesta, encaminada a reducir el excedente dermo-graso mediante maniobras bidigitales y colocando la cicatriz resultante en el surco braquial interno. El resultado obtenido fue satisfactorio y las complicaciones mínimas y locales, del tipo de dehiscencia, cicatriz hipertrófica, hematoma y linfocele. Ninguna complicación comprometió el resultado final. La simplicidad del procedimiento y los resultado satisfactorios, con baja morbilidad y buena posición de las cicatrices, hacen que el abordaje que practicamos sea una buena opción quirúrgica para el tratamiento de las deformidades de los miembros superiores.The uppers limbs represent a very important aestheticfunctionary unit in the body contouring definition. Because of the popularization of the body contour surgery after massive weight loss, there has been noted a raise in the number of brachioplasties in the last years. Our proposal is to show the author experience in brachioplasty, focusing a new approach for correction of flaccidity associated or not to lipodystrophy of the arms. This article represents a retrospective study of 22 patients submitted to brachioplasty with the approach proposed by the authors. It consists in the resection of the excess of fat and skin in the arms using bidigital maneuver aiming to leave the final scar in

  14. Global Coronal Waves

    CERN Document Server

    Chen, P F

    2016-01-01

    After the {\\em Solar and Heliospheric Observatory} ({\\em SOHO}) was launched in 1996, the aboard Extreme Ultraviolet Imaging Telescope (EIT) observed a global coronal wave phenomenon, which was initially named "EIT wave" after the telescope. The bright fronts are immediately followed by expanding dimmings. It has been shown that the brightenings and dimmings are mainly due to plasma density increase and depletion, respectively. Such a spectacular phenomenon sparked long-lasting interest and debates. The debates were concentrated on two topics, one is about the driving source, and the other is about the nature of this wavelike phenomenon. The controversies are most probably because there may exist two types of large-scale coronal waves that were not well resolved before the {\\em Solar Dynamics Observatory} ({\\em SDO}) was launched: one is a piston-driven shock wave straddling over the erupting coronal mass ejection (CME), and the other is an apparently propagating front, which may correspond to the CME frontal...

  15. Cercamientos y derechos comunales en la Inglaterra del siglo XIII: Un abordaje historiográfico en torno al Estatuto de Merton [1236

    Directory of Open Access Journals (Sweden)

    Lucio Mir

    2011-04-01

    Full Text Available El siguiente trabajo intenta un abordaje general de las diversas interpretaciones relativas a un documento del siglo XIII, el Estatuto de Merton [1236]. El contexto que preside este abordaje fueron las transformaciones del sistema económico feudal y, en sus aspectos específicos, apunta a reconsiderar el proceso de cercamiento en la Inglaterra de aquel siglo. A pesar de que muchas investigaciones planteen el origen de las enclosures en los siglos XV y XVI, el Estatuto estaría atestiguando su presencia anterior. El presente trabajo procura reflexionar sobre las producciones historiográficas que se han realizado en relación al tema. El estudio de este notable documento adquiere importancia para analizar los antecedentes de la transición del feudalismo al capitalismo

  16. Abordaje transumbilical en pacientes pediátricos con sospecha de apendicitis aguda. Un serie de 424 pacientes

    Directory of Open Access Journals (Sweden)

    Luis Augusto Zárate Suárez

    2013-05-01

    Full Text Available Antecedentes: El tratamiento de la apendicitis aguda implica su extirpación; es frecuente la solicitud de cicatrices postquirúrgicas del mejor tamaño posible. Una de las estrategias disponibles es el abordaje transumbilical. Objetivos: Descubrir las características clínicas y los desenlaces operatorios de los pacientes pediátricos en quienes se realiza apendicectomía vía transumbilical. Metodología: Estudio prospectivo de 424 pacientes sucesivos en cuanto a los desenlaces operatorios a corto plazo. Resultados: El tiempo promedio de intervención quirúrgica fue de 22 minutos; 95,8% de los pacientes presentó evolución satisfactoria del postquirúrgico; 1,4% de los pacientes se reintervino para drenar un absceso intracavitario residual y 0,2% presentó infencción de sitio operatorio sin mas complicaciones. Conclusión: El abordaje transumbilical de la apendicitis es una alternativa minimamente invasiva para todos los estados de apendicitis aguda e implica disminución del tiempo de realización, menor estancia del postquirúrgico, menor incidencia de complicaciones y mayor conformidad con los resultados estéticos.

  17. Coronal Mass Ejections

    CERN Document Server

    Kunow, H; Linker, J. A; Schwenn, R; Steiger, R

    2006-01-01

    It is well known that the Sun gravitationally controls the orbits of planets and minor bodies. Much less known, however, is the domain of plasma fields and charged particles in which the Sun governs a heliosphere out to a distance of about 15 billion kilometers. What forces activates the Sun to maintain this power? Coronal Mass Ejections (CMEs) and their descendants are the troops serving the Sun during high solar activity periods. This volume offers a comprehensive and integrated overview of our present knowledge and understanding of Coronal Mass Ejections (CMEs) and their descendants, Interplanetary CMEs (ICMEs). It results from a series of workshops held between 2000 and 2004. An international team of about sixty experimenters involved e.g. in the SOHO, ULYSSES, VOYAGER, PIONEER, HELIOS, WIND, IMP, and ACE missions, ground observers, and theoreticians worked jointly on interpreting the observations and developing new models for CME initiations, development, and interplanetary propagation. The book provides...

  18. Abordaje psicoterapeutico sistémico individual con jóvenes diagnosticados con trastorno de somatización

    OpenAIRE

    Silva Guzmán, María Angélica

    2010-01-01

    Esta investigación tiene por objetivo comprender los procesos de cambio y transformación de narrativas en el joven diagnosticado con trastorno de somatización a través de un abordaje de intervención sistémica individual. Se realizó una investigación de corte cualitativo, utilizando la modalidad de investigación intervención, con metodología de estudio de caso con diseño de casos múltiples con única unidad de análisis, trabajando en el análisis y evaluación de las herramientas terapéuticas inf...

  19. ¿Es razonable el abordaje laparoscópico en patología maligna colo-rectal?

    OpenAIRE

    Hernandez-Lizoain, J.L. (Jose Luis); Diez-Caballero, A. (Alberto); J. Baixauli; F. Martinez; F. Pardo; Cienfuegos, J.A. (Javier A.)

    1999-01-01

    Desde que se efectuó la primera resección de colon por vía laparoscópica en 1990, han sido publicados numerosos artículos, manifestándose diferentes opiniones, algunas de ellas francamente contrapuestas, en cuanto a validez o no de esta vía de abordaje quirúrgico, para el tratamiento del cáncer colo-rectal. El presente estudio de revisión pretende poner en claro cuál es la situación actual de la resección de colon por vía laparoscópica. Se analizan las ventajas e inconvenientes de dicho tr...

  20. Propuesta de abordaje sobre determinantes sociales de la salud y cambio climático en comunidades dependientes de los desechos sólidos en Managua, Nicaragua

    OpenAIRE

    2014-01-01

    OBJETIVOS: Esta investigación elabora una propuesta de abordaje sobre los determinantes sociales de la salud y el cambio climático en una comunidad dependiente de los desechos sólidos en la ciudad de Managua, Nicaragua. Partiendo del análisis social y económico, tanto del país como de la comunidad en estudio, se plantean acciones sociales y económicas basadas en los determinantes sociales que inciden en la salud. DESCRIPCIÓN: Con base en el análisis social y económico hecho a la población dep...

  1. Propuesta de abordaje sobre determinantes sociales de la salud y cambio climático en comunidades dependientes de los desechos sólidos en Managua, Nicaragua

    OpenAIRE

    2014-01-01

    OBJETIVOS: Esta investigación elabora una propuesta de abordaje sobre los determinantes sociales de la salud y el cambio climático en una comunidad dependiente de los desechos sólidos en la ciudad de Managua, Nicaragua. Partiendo del análisis social y económico, tanto del país como de la comunidad en estudio, se plantean acciones sociales y económicas basadas en los determinantes sociales que inciden en la salud. DESCRIPCIÓN: Con base en el análisis social y económico hecho ...

  2. Abordaje fisioterapéutico en el Síndrome del Corredor (Banda Ilitibial). Revisión bibliográfica

    OpenAIRE

    Caraballo Viña, Javier

    2016-01-01

    [ES]Introducción: El running es una práctica deportiva muy extendida. Los beneficios asociados al running son innumerables, pero pueden acarrear la aparición de una serie de patologías. El propósito de esta revisión fue recopilar los abordajes fisioterapéuticos que son atribuidos a la patología del SBIT y el estudio de su evidencia científica. Método: Se realizó una revisión bibliográfica desde 2005 en ScienceDirect, SportsDiscus with Full text (EBSCO), Scopus, Cochcrane Database of Systemati...

  3. ASPECTOS ONTOLÓGICOS Y EPISTEMOLÓGICOS EN LAS RELACIONES INTERNACIONALES: BREVES PROPUESTAS DE ABORDAJES TEÓRICOS

    Directory of Open Access Journals (Sweden)

    Alberto Lozano Vázquez

    2016-06-01

    Full Text Available El presente ensayo tiene por objetivo analizar los aspectos ontológicos y epistemológicos que han nutrido y formado la construcción teórica de las Relaciones Internacionales (RI. El argumento es una afirmación condicional y es sencilla: Si no se comprenden los fundamentos ontológicos y epistemológicos de las RI entonces no hay precisión en el abordaje teórico de los casos de estudio. Los casos de estudio pueden ser hechos, problemas o situaciones que ocurren en el mundo y la correcta aplicación de las teorías para su interpretación permite a los investigadores de esta disciplina encontrar mejores explicaciones y una mejor comprensión de éstos para, así, eventualmente, proponer soluciones asequibles a dichos problemas o situaciones. Se concluye que: 1 dependiendo del problema (variable dependiente se elige la teoría que mejor lo explique atribuyendo cierta causalidad (variable independiente, con las respectivas implicaciones ontológicas, epistemológicas y metodológicas; 2 que el carácter científico de la disciplina no es un asunto acabado; 3 que referirse a las teorías como paradigmas puede no ser tan útil como se cree; 4 que hay posibilidades dialógicas entre positivismo y post-positivismo para realizar preguntas de investigación en Relaciones Internacionales; y 5 que en la forma de ver el mundo está el abordaje teórico. La contribución consiste en orientar a los estudiosos de las RI en su elección teórica, dentro de varias opciones, para sus investigaciones científicosociales de carácter internacional.

  4. Coronal radiation belts

    CERN Document Server

    Hudson, H S; Frewen, S F N; DeRosa, M L

    2009-01-01

    The magnetic field of the solar corona has a large-scale dipole character, which maps into the bipolar field in the solar wind. Using standard representations of the coronal field, we show that high-energy ions can be trapped stably in these large-scale closed fields. The drift shells that describe the conservation of the third adiabatic invariant may have complicated geometries. Particles trapped in these zones would resemble the Van Allen Belts and could have detectable consequences. We discuss potential sources of trapped particles.

  5. Hemangioma capilar de la parótida. Abordaje transoral

    Directory of Open Access Journals (Sweden)

    Luis Domingo Sarra

    2014-10-01

    Presentamos un caso en una paciente adulta que consultó por una masa en la región parotídea y parálisis facial periférica con el mayor componente tumoral que se manifestaba en la cavidad oral. La ecografía mostró una masa sólida. La punción aspiración con aguja fina fue negativa con material hemático en 2 oportunidades. No tuvimos sospecha de la presencia de un tumor de origen vascular, por lo que no fue solicitada una RMN. El caso fue resuelto a través de un abordaje quirúrgico poco utilizado, tras obtener una biopsia por congelación negativa.

  6. Abordaje transconjuntival más transcaruncular: amplia exposición de la pared medial orbitaria. Una alternativa al abordaje coronal Transconjunctival, transcaruncular approach: enlarged orbital medial wall exposure. An alternative to the coronal approach

    Directory of Open Access Journals (Sweden)

    J. Rodríguez

    2008-06-01

    Full Text Available Los pliegues nasolabiales prominentes son uno de los aspectos que más preocupan a los pacientes candidatos a un lifting facial, y han sido descritas muchas técnicas que intentan atenuar este signo distintivo del envejecimiento. Las sustancias de relleno tienen limitaciones inherentes. Las disecciones amplias del SMAS y su posterior suspensión no tienen efecto después de transcurridas 24 horas. La suspensión de la almohadilla grasa malar tiene un efecto que se extiende como máximo a los dos años de duración. La extirpación directa de la grasa lateralmente al surco nasolabial, aunque debe hacerse con mucha cautela, es la única técnica que proporciona resultados permanentes. Técnicamente, esta resección grasa se ha descrito realizada valiéndose de pinzas y tijeras, con cánulas de liposucción o con curetas. Este procedimiento requiere un control muy preciso, táctil y visual, de la localización y profundidad de la extirpación, control que puede mejorarse usando una gubia ósea con una mano para extirpar la grasa a eliminar de la dermis, mientras la otra mano maneja el colgajo cutáneo de la mejilla, para un control alternativo interno y externo del efecto escultural de la extirpación y para permitir una guía táctil externa.Prominent nasolabial folds are of concern to many face lift candidates. Many techniques have been described which tackle this distinct sign of ageing. Crease fillers have inherent limitations. Extended SMAS dissection and suspension has no effect after 24 hours. Malar fat pad suspension has an effect which extends maximally to 2 years. Direct fat excision lateral to the crease must be done cautiously. However, it is the only technique providing permanent results. Fat removal can be done with tweezers and scissors, with liposuction canules, and with curettes. Tactile and visual control over location and depth of the resection is required. Such is possible when using a bone rongeur in one hand to reduce the fat mount which has been dissected off the dermis. The other hand turns over the cheek flap for alternating internal and external control of the sculpturing effect, and for external tactile guidance.

  7. Coronal Mass Ejections: Observations

    Directory of Open Access Journals (Sweden)

    David F. Webb

    2012-06-01

    Full Text Available Solar eruptive phenomena embrace a variety of eruptions, including flares, solar energetic particles, and radio bursts. Since the vast majority of these are associated with the eruption, development, and evolution of coronal mass ejections (CMEs, we focus on CME observations in this review. CMEs are a key aspect of coronal and interplanetary dynamics. They inject large quantities of mass and magnetic flux into the heliosphere, causing major transient disturbances. CMEs can drive interplanetary shocks, a key source of solar energetic particles and are known to be the major contributor to severe space weather at the Earth. Studies over the past decade using the data sets from (among others the SOHO, TRACE, Wind, ACE, STEREO, and SDO spacecraft, along with ground-based instruments, have improved our knowledge of the origins and development of CMEs at the Sun and how they contribute to space weather at Earth. SOHO, launched in 1995, has provided us with almost continuous coverage of the solar corona over more than a complete solar cycle, and the heliospheric imagers SMEI (2003 – 2011 and the HIs (operating since early 2007 have provided us with the capability to image and track CMEs continually across the inner heliosphere. We review some key coronal properties of CMEs, their source regions and their propagation through the solar wind. The LASCO coronagraphs routinely observe CMEs launched along the Sun-Earth line as halo-like brightenings. STEREO also permits observing Earth-directed CMEs from three different viewpoints of increasing azimuthal separation, thereby enabling the estimation of their three-dimensional properties. These are important not only for space weather prediction purposes, but also for understanding the development and internal structure of CMEs since we view their source regions on the solar disk and can measure their in-situ characteristics along their axes. Included in our discussion of the recent developments in CME

  8. The coronal fricative problem

    Science.gov (United States)

    Dinnsen, Daniel A.; Dow, Michael C.; Gierut, Judith A.; Morrisette, Michele L.; Green, Christopher R.

    2013-01-01

    This paper examines a range of predicted versus attested error patterns involving coronal fricatives (e.g. [s, z, θ, ð]) as targets and repairs in the early sound systems of monolingual English-acquiring children. Typological results are reported from a cross-sectional study of 234 children with phonological delays (ages 3 years; 0 months to 7;9). Our analyses revealed different instantiations of a putative developmental conspiracy within and across children. Supplemental longitudinal evidence is also presented that replicates the cross-sectional results, offering further insight into the life-cycle of the conspiracy. Several of the observed typological anomalies are argued to follow from a modified version of Optimality Theory with Candidate Chains (McCarthy, 2007). PMID:24790247

  9. Variabilidad en el abordaje de las heridas crónicas: ¿qué opinan las enfermeras?

    Directory of Open Access Journals (Sweden)

    José Antonio Esperón Güimil

    Full Text Available Objetivo: conocer las opiniones de las enfermeras sobre la variabilidad en el abordaje y manejo de las heridas crónicas, así como los factores que la causan. Métodos: cumplimentación voluntaria de un cuestionario por enfermeras de los tres niveles asistenciales. El cuestionario incluía ítems sociodemográficos, nivel asistencial, nivel de formación en heridas, implicación en investigación y si consideraban que existe variabilidad en el abordaje de las heridas crónicas. Resultados: porcentaje de respuesta del 14%. El 90% consideraba que existía variabilidad. Enumeraron 202 razones para explicar esa variabilidad, que se clasificaron en diez causas. Un porcentaje elevado considera que tiene formación específica en heridas; sin embargo, más de la mitad de los encuestados (65,5% señala que la variabilidad está relacionada con un déficit de formación. Otras causas reflejadas fueron el "estilo de práctica profesional" (41%, la "discontinuidad de cuidados" (24,5% y el "exceso/escasez de productos" (14%. El análisis inferencial no mostró ninguna relación significativa entre las variables estudiadas y la respuesta de la existencia o no de variabilidad. Conclusión: Aunque las guías de práctica clínica reflejan recomendaciones basadas en la evidencia en el abordaje de las heridas crónicas, el estudio muestra que un alto porcentaje de las encuestadas consideran que existe variabilidad en el tratamiento de aquellas. A pesar del nivel de formación que dicen tener un gran número de encuestadas, una de las principales causas de la existencia de variabilidad es el déficit de formación, además del estilo de práctica profesional, la discontinuidad de cuidados y el exceso-escasez de productos.

  10. Entrevista não-diretiva: uma possibilidade de abordagem em grupo Entrevista no directiva: una posibilidad de abordaje en grupo Non-directive interview: a possibility of group approach

    Directory of Open Access Journals (Sweden)

    Maria Vitória Hoffmann

    2009-12-01

    Full Text Available Relato de experiência que descreve a abordagem metodológica entrevista não-diretiva, explicitando a possibilidade da abordagem em grupo. Apresenta os estudos que utilizaram este tipo de entrevista em grupo e a dinâmica de coleta de dados. Conclui-se que a abordagem possibilita ao pesquisador articular teoria e prática em torno de uma proposta de estudo.Relato de experiencia que describe el abordaje metodológico - entrevista no directiva; explicita la posibilidad del abordaje en grupo. Presenta los estudios que utilizaron la entrevista no directiva en grupo y la dinámica de la recollección de datos. Se concluye que el abordaje posibilita al investigador articular teoría y práctica en torno de una propuesta de estudio.Experience report that describes the methodological approach - non-directive interview, highlighting the possibility of group approach. It presents the studies that used this type of group and the dynamics of data collection. It was concluded that the approach enables the researcher to combine theory and practice around a study proposition.

  11. La experiencia de la delincuencia en dos abordajes etnográficos alternativos

    Directory of Open Access Journals (Sweden)

    Joaquín Santiago Gomez

    2011-10-01

    Full Text Available En este artículo reseñaré críticamente tres etnografías que han abordado la experiencia de la delincuencia en las sociedades contemporáneas. Lo haré señalando el modo en que han definido su objeto y realizado su trabajo, como es de rigor, pero sobre todo conduciendo la discusión a lo que entiendo dos formas radicalmente otras de construir el campo. Precisamente, atender al lugar diferencial que ocupa el "hecho delictivo" en estos trabajos antropológicos llevará a situar en líneas de indagación alternativas, por un lado, el reciente trabajo realizado en Argentina por Daniel Míguez y, por otro, dos etnografías brasileñas ancladas en la ciudad de Rio de Janeiro - entre las que encontramos una clara continuidad -, los trabajos de Alba Zaluar y Marcos Alvito. En un último apartado, me detendré a señalar la fructífera relación, no reconocida explícitamente en las etnografías que reseñamos, que esta línea de trabajo desarrollada en Brasil puede tener con los trabajos de Michel Foucault (esa relación es más patente en otros autores, como Michel Misse, cuya producción también podría ser incluida en esta perspectiva. De este modo, pretendo llamar la atención sobre aquellos abordajes que si bien pueden ofrecer aportes valiosos sobre tal o cual cuestión puntual, permanecen ciegos a los mismos fenómenos que la criminología convencional ignora dado que comparten con ésta la construcción de un campo de estudio centrado en la "delincuencia".

  12. Solar Coronal Plumes

    Directory of Open Access Journals (Sweden)

    Giannina Poletto

    2015-12-01

    Full Text Available Polar plumes are thin long ray-like structures that project beyond the limb of the Sun polar regions, maintaining their identity over distances of several solar radii. Plumes have been first observed in white-light (WL images of the Sun, but, with the advent of the space era, they have been identified also in X-ray and UV wavelengths (XUV and, possibly, even in in situ data. This review traces the history of plumes, from the time they have been first imaged, to the complex means by which nowadays we attempt to reconstruct their 3-D structure. Spectroscopic techniques allowed us also to infer the physical parameters of plumes and estimate their electron and kinetic temperatures and their densities. However, perhaps the most interesting problem we need to solve is the role they cover in the solar wind origin and acceleration: Does the solar wind emanate from plumes or from the ambient coronal hole wherein they are embedded? Do plumes have a role in solar wind acceleration and mass loading? Answers to these questions are still somewhat ambiguous and theoretical modeling does not provide definite answers either. Recent data, with an unprecedented high spatial and temporal resolution, provide new information on the fine structure of plumes, their temporal evolution and relationship with other transient phenomena that may shed further light on these elusive features.

  13. Coronal Seismology -- Achievements and Perspectives

    Science.gov (United States)

    Ruderman, Michael

    Coronal seismology is a new and fast developing branch of the solar physics. The main idea of coronal seismology is the same as of any branches of seismology: to determine basic properties of a medium using properties of waves propagating in this medium. The waves and oscillations in the solar corona are routinely observed in the late space missions. In our brief review we concentrate only on one of the most spectacular type of oscillations observed in the solar corona - the transverse oscillations of coronal magnetic loops. These oscillations were first observed by TRACE on 14 July 1998. At present there are a few dozens of similar observations. Shortly after the first observation of the coronal loop transverse oscillations they were interpreted as kink oscillations of magnetic tubes with the ends frozen in the dense photospheric plasma. The frequency of the kink oscillation is proportional to the magnetic field magnitude and inversely proportional to the tube length times the square root of the plasma density. This fact was used to estimate the magnetic field magnitude in the coronal loops. In 2004 the first simultaneous observation of the fundamental mode and first overtone of the coronal loop transverse oscillation was reported. If we model a coronal loop as a homogeneous magnetic tube, then the ratio of the frequencies of the first overtone and the fundamental mode should be equal to 2. However, the ratio of the observed frequencies was smaller than 2. This is related to the density variation along the loop. If we assume that the corona is isothermal and prescribe the loop shape (usually it is assumed that it has the shape of half-circle), then, using the ratio of the two frequencies, we can determine the temperature of the coronal plasma. The first observation of transverse oscillations of the coronal loops showed that they were strongly damped. This phenomenon was confirmed by the subsequent observations. At present, the most reliable candidate for the

  14. Geometry of solar coronal rays

    Science.gov (United States)

    Filippov, B. P.; Martsenyuk, O. V.; Platov, Yu. V.; Den, O. E.

    2016-02-01

    Coronal helmet streamers are the most prominent large-scale elements of the solar corona observed in white light during total solar eclipses. The base of the streamer is an arcade of loops located above a global polarity inversion line. At an altitude of 1-2 solar radii above the limb, the apices of the arches sharpen, forming cusp structures, above which narrow coronal rays are observed. Lyot coronagraphs, especially those on-board spacecrafts flying beyond the Earth's atmosphere, enable us to observe the corona continuously and at large distances. At distances of several solar radii, the streamers take the form of fairly narrow spokes that diverge radially from the Sun. This radial direction displays a continuous expansion of the corona into the surrounding space, and the formation of the solar wind. However, the solar magnetic field and solar rotation complicate the situation. The rotation curves radial streams into spiral ones, similar to water streams flowing from rotating tubes. The influence of the magnetic field is more complex and multifarious. A thorough study of coronal ray geometries shows that rays are frequently not radial and not straight. Coronal streamers frequently display a curvature whose direction in the meridional plane depends on the phase of the solar cycle. It is evident that this curvature is related to the geometry of the global solar magnetic field, which depends on the cycle phase. Equatorward deviations of coronal streamers at solar minima and poleward deviations at solar maxima can be interpreted as the effects of changes in the general topology of the global solar magnetic field. There are sporadic temporal changes in the coronal rays shape caused by remote coronal mass ejections (CMEs) propagating through the corona. This is also a manifestation of the influence of the magnetic field on plasma flows. The motion of a large-scale flux rope associated with a CME away from the Sun creates changes in the structure of surrounding field

  15. Ponderomotive Acceleration in Coronal Loops

    Science.gov (United States)

    Dahlburg, R. B.; Laming, J. M.; Taylor, B. D.; Obenschain, K.

    2016-11-01

    Ponderomotive acceleration has been asserted to be a cause of the first ionization potential (FIP) effect, the well-known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a “by-product” of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of coronal loops with an axial magnetic field from 0.005 to 0.02 T and lengths from 25,000 to 75,000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets, which act to heat the loop. As a consequence of coronal magnetic reconnection, small-scale, high-speed jets form. The familiar vortex quadrupoles form at reconnection sites. Between the magnetic footpoints and the corona the reconnection flow merges with the boundary flow. It is in this region that the ponderomotive acceleration occurs. Mirroring the character of the coronal reconnection, the ponderomotive acceleration is also found to be intermittent.

  16. Coronal Mass Ejections An Introduction

    CERN Document Server

    Howard, Timothy

    2011-01-01

    In times of growing technological sophistication and of our dependence on electronic technology, we are all affected by space weather. In its most extreme form, space weather can disrupt communications, damage and destroy spacecraft and power stations, and increase radiation exposure to astronauts and airline passengers. Major space weather events, called geomagnetic storms, are large disruptions in the Earth’s magnetic field brought about by the arrival of enormous magnetized plasma clouds from the Sun. Coronal mass ejections (CMEs) contain billions of tons of plasma and hurtle through space at speeds of several million miles per hour. Understanding coronal mass ejections and their impact on the Earth is of great interest to both the scientific and technological communities. This book provides an introduction to coronal mass ejections, including a history of their observation and scientific revelations, instruments and theory behind their detection and measurement, and the status quo of theories describing...

  17. Motion magnification in coronal seismology

    CERN Document Server

    Anfinogentov, Sergey

    2016-01-01

    We introduce a new method for the investigation of low-amplitude transverse oscillations of solar plasma non-uniformities, such as coronal loops, individual strands in coronal arcades, jets, prominence fibrils, polar plumes, and other contrast features, observed with imaging instruments. The method is based on the two-dimensional dual tree complex wavelet transform (DT$\\mathbb{C}$WT). It allows us to magnify transverse, in the plane-of-the-sky, quasi-periodic motions of contrast features in image sequences. The tests performed on the artificial data cubes imitating exponentially decaying, multi-periodic and frequency-modulated kink oscillations of coronal loops showed the effectiveness, reliability and robustness of this technique. The algorithm was found to give linear scaling of the magnified amplitudes with the original amplitudes provided they are sufficiently small. Also, the magnification is independent of the oscillation period in a broad range of the periods. The application of this technique to SDO/A...

  18. Coronal Fourier power spectra: implications for coronal seismology and coronal heating

    CERN Document Server

    Ireland, Jack; Inglis, Andrew R

    2014-01-01

    The dynamics of regions of the solar corona are investigated using Atmospheric Imaging Assembly (AIA) 171\\AA\\ and 193\\AA\\ data. The coronal emission from the quiet Sun, coronal loop footprints, coronal moss, and from above a sunspot is studied. It is shown that the mean Fourier power spectra in these regions can be described by a power law at lower frequencies that tails to flat spectrum at higher frequencies, plus a Gaussian-shaped contribution that varies depending on the region studied. This Fourier spectral shape is in contrast to the commonly-held assumption that coronal time-series are well described by the sum of a long time-scale background trend plus Gaussian-distributed noise, with some specific locations also showing an oscillatory signal. The implications of this discovery to the field of coronal seismology and the automated detections of oscillations are discussed. The power law contribution to the shape of the Fourier power spectrum is interpreted as being due to the summation of a distribution ...

  19. A Solar Coronal Jet Event Triggers A Coronal Mass Ejection

    CERN Document Server

    Liu, Jiajia; Shen, Chenglong; Liu, Kai; Pan, Zonghao; Wang, S

    2015-01-01

    We present the multi-point and multi-wavelength observation and analysis on a solar coronal jet and coronal mass ejection (CME) event in this paper. Employing the GCS model, we obtained the real (three-dimensional) heliocentric distance and direction of the CME and found it propagate in a high speed over 1000 km/s . The jet erupted before and shared the same source region with the CME. The temporal and spacial relation- ship between them guide us the possibility that the jet triggered the CME and became its core. This scenario could promisingly enrich our understanding on the triggering mechanism of coronal mass ejections and their relations with coronal large-scale jets. On the other hand, the magnetic field configuration of the source region observed by the SDO/HMI instrument and the off- limb inverse Y-shaped configuration observed by SDO/AIA 171 A passband, together provide the first detailed observation on the three-dimensional reconnection process of large-scale jets as simulated in Pariat et al. 2009. ...

  20. Coronal ``Wave'': Magnetic Footprint of a Coronal Mass Ejection?

    Science.gov (United States)

    Attrill, Gemma D. R.; Harra, Louise K.; van Driel-Gesztelyi, Lidia; Démoulin, Pascal

    2007-02-01

    We investigate the properties of two ``classical'' EUV Imaging Telescope (EIT) coronal waves. The two source regions of the associated coronal mass ejections (CMEs) possess opposite helicities, and the coronal waves display rotations in opposite senses. We observe deep core dimmings near the flare site and also widespread diffuse dimming, accompanying the expansion of the EIT wave. We also report a new property of these EIT waves, namely, that they display dual brightenings: persistent ones at the outermost edge of the core dimming regions and simultaneously diffuse brightenings constituting the leading edge of the coronal wave, surrounding the expanding diffuse dimmings. We show that such behavior is consistent with a diffuse EIT wave being the magnetic footprint of a CME. We propose a new mechanism where driven magnetic reconnections between the skirt of the expanding CME magnetic field and quiet-Sun magnetic loops generate the observed bright diffuse front. The dual brightenings and the widespread diffuse dimming are identified as innate characteristics of this process.

  1. Exploring Coronal Structures with SOHO

    Indian Academy of Sciences (India)

    Μ. Karovska; Β. Wood; J. Chen; J. Cook; R. Howard

    2000-09-01

    We applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

  2. Descripción de nuevo abordaje quirúrgico anterior al codo

    OpenAIRE

    Ramírez Gallego, Alejandro

    2015-01-01

    Los accesos medial, lateral y posterior al codo permiten la visualización y manejo de la mayor parte de las patologías traumáticas de esta articulación. Sin embargo cuando se trata de fracturas de la coronoides o de la porción articular anterior de la tróclea y el capitelum, estas vías clásicas tienen limitaciones ya que se requieren abordajes amplios con desinserciones ligamentarias, dobles abordajes u osteotomías para lograr una exposición adecuada. Se realizó disección anató...

  3. Nuevo abordaje en el manejo del aborto diferido

    OpenAIRE

    Gippini Requeijo, Isabel

    2012-01-01

    El aborto diferido es una de las patologías obstétricas a las que nos enfrentamos con mayor frecuencia, ya que alrededor del 25% de las mujeres experimentarán un aborto precoz a lo largo de su vida, y su diagnóstico supone un revés emocional para la pareja. El poder ofrecer alternativas de tratamiento seguras y eficaces y, que además supongan un ahorro en los costes resulta de gran utilidad. Por ello es necesario realizar estudios que ayuden a establecer las dosis adecuadas, la seguridad en e...

  4. Abordaje metodológico para la exploración de la experiencia emocional en sus distintas dimensiones

    Directory of Open Access Journals (Sweden)

    Claudia J. Arias

    2013-12-01

    Full Text Available La experiencia emocional es un constructo complejo y multidimensional. En este artículo se propone un abordaje comprensivo de triangulación metodológica. El mismo se basa el modelo de Experiencia emocional propuesto por Lawton, que incluye una serie de dimensiones que permiten explorar gran variedad de aspectos de este constructo a través de las escalas: 1 Intensidad del afecto, 2 Moderación del afecto positivo, 3 Búsqueda de sensaciones, 4 Control cognitivo, 5 Madurez emocional, 6  Disimulación afectiva, 7 Responsividad psicofisiológica, 8 Variabilidad afectiva, 9 Duración del afecto, 10 Rapidez de la respuesta afectiva. En lo relativo a la exploración cualitativa se proponen  indagar situaciones cotidianas en las que se aplican estrategias de Control Cognitivo, Simulación Emocional, la Selección de situaciones y la Búsqueda de sensaciones en el encuadre de una entrevista semi-estructurada diseñada para este estudio. Se incluyen los datos del proceso de validación en población de la ciudad de Mar del Plata, las características de la muestra seleccionada para el estudio y el procedimiento de administración de instrumentos aplicado. Respecto del análisis de datos, se describen las técnicas estadísticas (descriptivas e inferenciales y de análisis de contenido (técnicas inductivas aplicadas.

  5. A fuzzy decision support system for meta-evaluation a new approach and a case study performed in Brazil Un sistema de suporte a la decisión para meta-evaluación y sus consecuencias: nueva abordaje y estudio de caso realizado en Brasil Um sistema fuzzy de suporte à decisão para meta-avaliação uma nova abordagem e um estudo de caso desenvolvidos no Brasil

    Directory of Open Access Journals (Sweden)

    Ana Carolina Letichevsky

    2007-09-01

    Full Text Available This paper presents a new methodology for meta-evaluation that makes use of fuzzy sets and fuzzy logic. It is composed of a data collection instrument and of a hierarchical fuzzy inference system. The advantages of the proposed methodology are: (i the instrument, which allows intermediate answers; (ii the inference process ability to adapt to specific needs; and (iii transparency, through the use of linguistic rules that facilitate both the understanding and the discussion of the whole process. The rules are based on guidelines established by the Joint Committee on Standards for Educational Evaluation (1994 and also represent the view of experts. The system can provide support to evaluators that may lack experience in meta-evaluation. A case study is presented as a validation of the proposed methodology.Este artículo presenta una nueva metodología para meta-evaluación que utiliza conjuntos fuzzy e lógica fuzzy. Esta metodología es compuesta por un instrumento de coleta de dados y por uno sistema de inferencia fuzzy. Las ventajas de la metodología propuesta son: (i el instrumento de coleta de dados, que permite respuestas intermediarias; (ii la capacidad del sistema de inferencia de adaptarse a necesidades específicas; (iii transparencia, a través de la utilización de reglas lingüísticas que facilitan tanto el entendimiento como la discusión de todo el proceso. Las reglas fueron construidas con base en las directrices establecidas por el Joint Committee on Standards for Educational Evaluation(1994 y por informaciones fornecidas por especialistas. El sistema puede auxiliar evaluadores que aún no tienen experiencia en meta-evaluación. Un estudio de caso es presentado comovalidación de la Metodología propuesta.Este artigo apresenta uma nova metodologia para meta-avaliação que utiliza conjuntos fuzzy e lógica fuzzy. Esta metodologia é composta por um instrumento de coleta de dados e por um sistema hierárquico de inferência fuzzy

  6. Intrinsic Instability of Coronal Streamers

    CERN Document Server

    Chen, Y; Song, H Q; Shi, Q Q; Feng, S W; Xia, L D; 10.1088/0004-637X/691/2/1936

    2009-01-01

    Plasma blobs are observed to be weak density enhancements as radially stretched structures emerging from the cusps of quiescent coronal streamers. In this paper, it is suggested that the formation of blobs is a consequence of an intrinsic instability of coronal streamers occurring at a very localized region around the cusp. The evolutionary process of the instability, as revealed in our calculations, can be described as follows: (1) through the localized cusp region where the field is too weak to sustain the confinement, plasmas expand and stretch the closed field lines radially outward as a result of the freezing-in effect of plasma-magnetic field coupling; the expansion brings a strong velocity gradient into the slow wind regime providing the free energy necessary for the onset of a subsequent magnetohydrodynamic instability; (2) the instability manifests itself mainly as mixed streaming sausage-kink modes, the former results in pinches of elongated magnetic loops to provoke reconnections at one or many loc...

  7. Ponderomotive Acceleration in Coronal Loops

    CERN Document Server

    Dahlburg, R B; Taylor, B D; Obenschain, K

    2016-01-01

    Ponderomotive acceleration has been asserted to be a cause of the First Ionization Potential (FIP) effect, the by now well known enhancement in abundance by a factor of 3-4 over photospheric values of elements in the solar corona with FIP less than about 10 eV. It is shown here by means of numerical simulations that ponderomotive acceleration occurs in solar coronal loops, with the appropriate magnitude and direction, as a "byproduct" of coronal heating. The numerical simulations are performed with the HYPERION code, which solves the fully compressible three-dimensional magnetohydrodynamic equations including nonlinear thermal conduction and optically thin radiation. Numerical simulations of a coronal loops with an axial magnetic field from 0.005 Teslas to 0.02 Teslas and lengths from 25000 km to 75000 km are presented. In the simulations the footpoints of the axial loop magnetic field are convected by random, large-scale motions. There is a continuous formation and dissipation of field-aligned current sheets...

  8. Motion Magnification in Coronal Seismology

    Science.gov (United States)

    Anfinogentov, Sergey; Nakariakov, Valery M.

    2016-11-01

    We introduce a new method for the investigation of low-amplitude transverse oscillations of solar plasma non-uniformities, such as coronal loops, individual strands in coronal arcades, jets, prominence fibrils, polar plumes, and other contrast features that have been observed with imaging instruments. The method is based on the two-dimensional dual-tree complex wavelet transform (DTℂWT). It allows us to magnify transverse, in the plane-of-the-sky, quasi-periodic motions of contrast features in image sequences. The tests performed on the artificial data cubes that imitated exponentially decaying, multi-periodic and frequency-modulated kink oscillations of coronal loops showed the effectiveness, reliability, and robustness of this technique. The algorithm was found to give linear scaling of the magnified amplitudes with the original amplitudes, provided these are sufficiently small. In addition, the magnification is independent of the oscillation period in a broad range of the periods. The application of this technique to SDO/AIA EUV data cubes of a non-flaring active region allowed for the improved detection of low-amplitude decay-less oscillations in the majority of loops.

  9. Estudio del engagement como factor de capital psicológico positivo y su rol en la calidad de servicio. Análisis de casos

    OpenAIRE

    Redondo, Ana Isabel; Arraigada, Mariana Cecilia

    2013-01-01

    El presente trabajo busca analizar los resultados obtenidos en el estudio realizado sobre organizaciones de servicios relevando el nivel de engagement del empleado y el nivel de clima organización. A través de un abordaje desde el marco teórico del capital psicológico positivo, aplicando las variables relevadas como factores generadores del mismo, se ofrece una interpretación de la información relevada en dicho estudio.

  10. A SOLAR CORONAL JET EVENT TRIGGERS A CORONAL MASS EJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiajia; Wang, Yuming; Shen, Chenglong; Liu, Kai; Pan, Zonghao; Wang, S. [CAS Key Laboratory of Geospace Environment, Earh and Space Science School, University of Science and Technology of China, No. 96, JinZhai Road, Hefei, Anhui 230026 (China)

    2015-11-10

    In this paper, we present multi-point, multi-wavelength observations and analysis of a solar coronal jet and coronal mass ejection (CME) event. Employing the GCS model, we obtained the real (three-dimensional) heliocentric distance and direction of the CME and found it to propagate at a high speed of over 1000 km s{sup −1}. The jet erupted before the CME and shared the same source region. The temporal and spacial relationship between these two events lead us to the possibility that the jet triggered the CME and became its core. This scenario hold the promise of enriching our understanding of the triggering mechanism of CMEs and their relations to coronal large-scale jets. On the other hand, the magnetic field configuration of the source region observed by the Solar Dynamics Observatory (SDO)/HMI instrument along with the off-limb inverse Y-shaped configuration observed by SDO/AIA in the 171 Å passband provide the first detailed observation of the three-dimensional reconnection process of a large-scale jet as simulated in Pariat et al. The eruption process of the jet highlights the importance of filament-like material during the eruption of not only small-scale X-ray jets, but likely also of large-scale EUV jets. Based on our observations and analysis, we propose the most probable mechanism for the whole event, with a blob structure overlaying the three-dimensional structure of the jet, to describe the interaction between the jet and the CME.

  11. Abordaje contrafáctico, inferencia causal y el enfoque de la puntuación de la propensión. Efectos de las remesas en la escolarización paraguaya

    Directory of Open Access Journals (Sweden)

    Pablo Sebastián Gómez

    2014-01-01

    Full Text Available La mayoría de la investigación en ciencias sociales en general y en el campo de los estudios migratorios en particular, está confrontada con el problema de la causalidad cuando evalúa el impacto de alguna variable de interés. El abordaje contrafáctico permite solucionar los problemas derivados de la asignación no aleatoria de las poblaciones bajo estudio a los grupos de control y tratamiento. En este artículo presentamos los problemas de analizar los efectos causales de las remesas provenientes del Sur Global en Paraguay, proponemos una solución y estimamos los efectos en la escolarización paraguaya. Los principales resultados obtenidos sugieren que no hay efectos en la inversión en capital humano y las potencialidades del enfoque de la puntuación de la propensión.

  12. From Forbidden Coronal Lines to Meaningful Coronal Magnetic Fields

    CERN Document Server

    Judge, Philip G; Landi, Enrico

    2013-01-01

    We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of magnetic free energy within coronal plasmas. We address commonly held skepticisms concerning angular ambiguities and line-of-sight confusion. We argue that ambiguities are in principle no worse than more familiar remotely sensed photospheric vector-fields, and that the diagnosis of M1 line data would benefit from simultaneous observations of EUV lines. Based on calculations and data from eclipses, we discuss the most promising lines and different approaches that might be used. We point to the S-like [Fe {\\sc XI}] line (J=2 to J=1) at 789.2nm as a prime target line (for ATST for example) to augment the hotter 1074.7 and 1079.8 nm Si-like lines of [Fe {\\sc XIII}] currently observed by the Coronal Multi-channel Polarimeter (CoMP). Significant breakthroughs will be made possibl...

  13. Deep coronal hole associated with quiescent filament

    Science.gov (United States)

    Kesumaningrum, Rasdewita; Herdiwidjaya, Dhani

    2014-03-01

    We present a study of the morphology of quiescent filament observed by H-alpha Solar Telescope at Bosscha Observatory in association with coronal hole observed by Atmospheric Imaging Assembly (AIA) instrument in 193 Å from Solar Dynamics Observatory. H-alpha images were processed by imaging softwares, namely Iris 5.59 and ImageJ, to enhance the signal to noise ratio and to identify the filament features associated with coronal hole. For images observed on October 12, 2011, November 14, 2011 and January 2, 2012, we identified distinct features of coronal holes above the quiescent filaments. This associated coronal holes have filament-like morphology with a thick long thread as it's `spine', defined as Deep Coronal Hole. Because of strong magnetic field of sunspot, these filaments and coronal holes emerged far from active region and lasted for several days. It is interesting as for segmented filament, deep coronal holes above the filaments lasted for a quite long period of time and merged. This association between filament and deep coronal hole can be explained by filament magnetic loop.

  14. La religión como objeto de análisis: sobre el concepto y tres vías de abordaje histórico

    Directory of Open Access Journals (Sweden)

    Patricia Alejandra Fogelman

    2015-01-01

    Full Text Available En este trabajo propongo pensar la “religión” y señalarla como área de estudios definiendo, en primera instancia, ese concepto en relación con otros como “religiosidad” y “religiosidad popular” usados frecuentemente en la historiografía. En segundo lugar, propongo formular tres vías –entre muchas otras vigentes- de abordaje sobre la religiosidad a modo de caminos programáticos posibles en el campo historiográfico (refiriéndome especialmente al caso argentino actual, pero no de manera excluyente. En ese sentido, los tres grandes ejes de esta propuesta a la que me refiero son el recurso de las imágenes, la creación y puesta en circulación de discursos religiosos, así como la consolidación de redes de relaciones sociales más o menos institucionalizadas en la órbita de la Iglesia constituyen, respectivamente, tres grandes vías de análisis centrales que merecen ser recorridas en la consolidación de un área de estudios históricos sobre la religiosidad. El ejercicio propuesto tiende a tratar de reconocer su matriz historiográfica en una mixtura entre la renovada historia social y la historia cultural.

  15. Abordagem por competências no processo ensino-aprendizagem Abordaje por competencia en proceso de enseñanza-aprendizaje Competence approach in teaching-learning process

    Directory of Open Access Journals (Sweden)

    César Cavalcanti da Silva

    2005-02-01

    Full Text Available O trabalho relata a experiência de um processo de ensino-aprendizagem baseado na abordagem por competências. O detalhamento desse processo de ensino revela a preocupação dos autores com a pouca ocorrência de estudos sobre o desenvolvimento prático do tema competências no âmbito das práticas educativas e, apontam para a necessidade de produção de mais estudos nessa dimensão.El trabajo menciona la experiencia del proceso de enseñanza-aprendizaje basada en la abordaje por competencia. El detalle de ese proceso de la enseñanza revela la preocupación de los autores en relación con los pocos estudios sobre el desarrollo práctico del tema de las competencias en la práctica educativa y, señalan la necesidad de más producción de los estudios en esa dimensión.The work relates the experience of the teaching-learning process based on the competence approach. The detail of that teaching process reveals the authors concern with the few occurrence of studies about the practical development of the competences theme in the Educational Practice and, point out to the need of more studies production in that dimension.

  16. Pre-flare coronal dimmings

    CERN Document Server

    Zhang, Q M; Ji, H S

    2016-01-01

    In this paper, we focus on the pre-flare coronal dimmings. We report our multiwavelength observations of the GOES X1.6 solar flare and the accompanying halo CME produced by the eruption of a sigmoidal magnetic flux rope (MFR) in NOAA active region (AR) 12158 on 2014 September 10. The eruption was observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamic Observatory (SDO). The photospheric line-of-sight magnetograms were observed by the Helioseismic and Magnetic Imager (HMI) aboard SDO. The soft X-ray (SXR) fluxes were recorded by the GOES spacecraft. The halo CME was observed by the white light coronagraphs of the Large Angle Spectroscopic Coronagraph (LASCO) aboard SOHO.} {About 96 minutes before the onset of flare/CME, narrow pre-flare coronal dimmings appeared at the two ends of the twisted MFR. They extended very slowly with their intensities decreasing with time, while their apparent widths (8$-$9 Mm) nearly kept constant. During the impulsive and decay phases of flare, typical fanlike ...

  17. Magnetic shuffling of coronal downdrafts

    Science.gov (United States)

    Petralia, A.; Reale, F.; Orlando, S.

    2017-02-01

    Context. Channelled fragmented downflows are ubiquitous in magnetized atmospheres, and have recently been addressed based on an observation after a solar eruption. Aims: We study the possible back-effect of the magnetic field on the propagation of confined flows. Methods: We compared two 3D magnetohydrodynamic simulations of dense supersonic plasma blobs that fall down along a coronal magnetic flux tube. In one, the blobs move strictly along the field lines; in the other, the initial velocity of the blobs is not perfectly aligned with the magnetic field and the field is weaker. Results: The aligned blobs remain compact while flowing along the tube, with the generated shocks. The misaligned blobs are disrupted and merge through the chaotic shuffling of the field lines. They are structured into thinner filaments. Alfvén wave fronts are generated together with shocks ahead of the dense moving front. Conclusions: Downflowing plasma fragments can be chaotically and efficiently mixed if their motion is misaligned with field lines, with broad implications for disk accretion in protostars, coronal eruptions, and rain, for example. Movies associated to Figs. 2 and 3 are available at http://www.aanda.org

  18. EIT waves and coronal magnetic field diagnostics

    Institute of Scientific and Technical Information of China (English)

    CHEN PengFei

    2009-01-01

    Magnetic field in the solar lower atmosphere can be measured by the use of the Zeeman and Hanle effects. By contrast, the coronal magnetic field well above the solar surface, which directly controls various eruptive phenomena, can not be precisely measured with the traditional techniques. Several attempts are being made to probe the coronal magnetic field, such as force-free extrapolation based on the photospheric magnetograms, gyroresonance radio emissions, and coronal seismology based on MHD waves in the corona. Compared to the waves trapped in the localized coronal loops, EIT waves are the only global-scale wave phenomenon, and thus are the ideal tool for the coronal global seismology. In this paper, we review the observations and modelings of EIT waves, and illustrate how they can be applied to probe the global magnetic field in the corona.

  19. The Inconvenient Truth About Coronal Dimmings

    CERN Document Server

    McIntosh, Scott W

    2008-01-01

    We investigate the occurrence of a coronal dimming using a combination of high resolution spectro-polarimetric, spectral and broadband images which span from the deep photosphere into the corona. These observations reinforce the belief that coronal dimmings, or transient coronal holes as they are also known, are indeed the locations of open magnetic flux in the corona resulting from the launch of a CME. We will see that, as open magnetic regions, they must act just as coronal holes and be sources of the fast solar wind, but only temporarily. An inescapable question therefore arises - what impact does this source of fast wind have on the propagation and in-flight characteristics of the CME that initiates the coronal dimming in the first place?

  20. Blind Stereoscopy of the Coronal Magnetic Field

    CERN Document Server

    Aschwanden, Markus J; Malanushenko, Anna

    2015-01-01

    We test the feasibility of 3D coronal-loop tracing in stereoscopic EUV image pairs, with the ultimate goal of enabling efficient 3D reconstruction of the coronal magnetic field that drives flares and coronal mass ejections (CMEs). We developed an automated code designed to perform triangulation of coronal loops in pairs (or triplets) of EUV images recorded from different perspectives. The automated (or blind) stereoscopy code includes three major tasks: (i) automated pattern recognition of coronal loops in EUV images, (ii) automated pairing of corresponding loop patterns from two different aspect angles, and (iii) stereoscopic triangulation of 3D loop coordinates. We perform tests with simulated stereoscopic EUV images and quantify the accuracy of all three procedures. In addition we test the performance of the blind stereoscopy code as a function of the spacecraft-separation angle and as a function of the spatial resolution. We also test the sensitivity to magnetic non-potentiality. The automated code develo...

  1. Guerra y paz al sur del Sahara. Nuevos abordajes conceptuales, frente a un escenario cambiante

    Directory of Open Access Journals (Sweden)

    Diego Buffa

    2014-05-01

    Full Text Available En este artículo nos proponemos presentar nuevas corrientes y abordajes conceptuales, que nos permitan comprender problemáticas capitales del África subsahariana, como lo son los conflictos intra-estatales, las emergencias políticas complejas, el intervencionismo humanitario y los procesos de paz, gestados durantela Posguerra Fría; portadores de inéditas lógicas y parámetros rectores.

  2. Guerra y paz al sur del Sahara. Nuevos abordajes conceptuales, frente a un escenario cambiante

    Directory of Open Access Journals (Sweden)

    Diego Buffa

    2014-01-01

    Full Text Available En este artículo nos proponemos presentar nuevas corrientes y abordajes concep - tuales, que nos permitan comprender problemáticas capitales del África subsaha - riana, como lo son los conflictos intra-estatales, las emergencias políticas comple - jas, el intervencionismo humanitario y los procesos de paz, gestados durante la Posguerra Fría; portadores de inéditas lógicas y parámetros rectores.

  3. Estudio epidemiológico de fracturas nasales en hospitales particulares de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Denis Pimenta E. Souza

    2014-10-01

    Conclusión: Este estudio proporciona datos básicos sobre las fracturas nasales, importantes para el abordaje terapéutico y la planificación, así como la mejora en la organización y el cuidado de estos pacientes, y la misma puede servir como un parámetro entre los diversos servicios hospitalarios para proporcionar una mejora continua en el servicio y la rutina quirúrgica.

  4. Network Coronal Bright Points: Coronal Heating Concentrations Found in the Solar Magnetic Network

    Science.gov (United States)

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Hathaway, D. H.

    1998-01-01

    We examine the magnetic origins of coronal heating in quiet regions by combining SOHO/EIT Fe xii coronal images and Kitt Peak magnetograms. Spatial filtering of the coronal images shows a network of enhanced structures on the scale of the magnetic network in quiet regions. Superposition of the filtered coronal images on maps of the magnetic network extracted from the magnetograms shows that the coronal network does indeed trace and stem from the magnetic network. Network coronal bright points, the brightest features in the network lanes, are found to have a highly significant coincidence with polarity dividing lines (neutral lines) in the network and are often at the feet of enhanced coronal structures that stem from the network and reach out over the cell interiors. These results indicate that, similar to the close linkage of neutral-line core fields with coronal heating in active regions (shown in previous work), low-lying core fields encasing neutral lines in the magnetic network often drive noticeable coronal heating both within themselves (the network coronal bright points) and on more extended field lines rooted around them. This behavior favors the possibility that active core fields in the network are the main drivers of the heating of the bulk of the quiet corona, on scales much larger than the network lanes and cells.

  5. Recent advances in coronal heating

    CERN Document Server

    De Moortel, Ineke

    2015-01-01

    The solar corona, the tenuous outer atmosphere of the Sun, is orders of magnitude hotter than the solar surface. This 'coronal heating problem' requires the identification of a heat source to balance losses due to thermal conduction, radiation and (in some locations) convection. The review papers in this Theo Murphy meeting issue present an overview of recent observational findings, large- and small-scale numerical modelling of physical processes occurring in the solar atmosphere and other aspects which may affect our understanding of the proposed heating mechanisms. At the same time, they also set out the directions and challenges which must be tackled by future research. In this brief introduction, we summarize some of the issues and themes which reoccur throughout this issue.

  6. Observational features of equatorial coronal hole jets

    Directory of Open Access Journals (Sweden)

    G. Zimbardo

    2010-03-01

    Full Text Available Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet events are selected by requiring at least some visibility in both COR1 and EUVI instruments. We report 15 jet events, and we discuss their main features. For one event, the uplift velocity has been determined as about 200 km s−1, while the deceleration rate appears to be about 0.11 km s−2, less than solar gravity. The average jet visibility time is about 30 min, consistent with jet observed in polar regions. On the basis of the present dataset, we provisionally conclude that there are not substantial physical differences between polar and equatorial coronal hole jets.

  7. FORWARD: A toolset for multiwavelength coronal magnetometry

    Science.gov (United States)

    Gibson, Sarah; Kucera, Therese; White, Stephen; Dove, James; Fan, Yuhong; Forland, Blake; Rachmeler, Laurel; Downs, Cooper; Reeves, Katharine

    2016-03-01

    Determining the 3D coronal magnetic field is a critical, but extremely difficult problem to solve. Since different types of multiwavelength coronal data probe different aspects of the coronal magnetic field, ideally these data should be used together to validate and constrain specifications of that field. Such a task requires the ability to create observable quantities at a range of wavelengths from a distribution of magnetic field and associated plasma -- i.e., to perform forward calculations. In this paper we describe the capabilities of the FORWARD SolarSoft IDL package, a uniquely comprehensive toolset for coronal magnetometry. FORWARD is a community resource that may be used both to synthesize a broad range of coronal observables, and to access and compare synthetic observables to existing data. It enables forward fitting of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. FORWARD can also be used to generate synthetic test beds from MHD simulations in order to facilitate the development of coronal magnetometric inversion methods, and to prepare for the analysis of future large solar telescope data.

  8. FORWARD: A toolset for multiwavelength coronal magnetometry

    Directory of Open Access Journals (Sweden)

    Sarah eGibson

    2016-03-01

    Full Text Available Determining the 3D coronal magnetic field is a critical, but extremely difficult problem to solve. Since different types of multiwavelength coronal data probe different aspects of the coronal magnetic field, ideally these data should be used together to validate and constrain specifications of that field. Such a task requires the ability to create observable quantities at a range of wavelengths from a distribution of magnetic field and associated plasma -- i.e., to perform forward calculations. In this paper we describe the capabilities of the FORWARD SolarSoft IDL package, a uniquely comprehensive toolset for coronal magnetometry. FORWARD is a community resource that may be used both to synthesize a broad range of coronal observables, and to access and compare synthetic observables to existing data. It enables forward fitting of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties. FORWARD can also be used to generate synthetic test beds from MHD simulations in order to facilitate the development of coronal magnetometric inversion methods, and to prepare for the analysis of future large solar telescope data.

  9. Space weather and coronal mass ejections

    CERN Document Server

    Howard, Tim

    2013-01-01

    Space weather has attracted a lot of attention in recent times. Severe space weather can disrupt spacecraft, and on Earth can be the cause of power outages and power station failure. It also presents a radiation hazard for airline passengers and astronauts. These ""magnetic storms"" are most commonly caused by coronal mass ejections, or CMES, which are large eruptions of plasma and magnetic field from the Sun that can reach speeds of several thousand km/s. In this SpringerBrief, Space Weather and Coronal Mass Ejections, author Timothy Howard briefly introduces the coronal mass ejection, its sc

  10. Slipping magnetic reconnection in coronal loops.

    Science.gov (United States)

    Aulanier, Guillaume; Golub, Leon; Deluca, Edward E; Cirtain, Jonathan W; Kano, Ryouhei; Lundquist, Loraine L; Narukage, Noriyuki; Sakao, Taro; Weber, Mark A

    2007-12-07

    Magnetic reconnection of solar coronal loops is the main process that causes solar flares and possibly coronal heating. In the standard model, magnetic field lines break and reconnect instantaneously at places where the field mapping is discontinuous. However, another mode may operate where the magnetic field mapping is continuous but shows steep gradients: The field lines may slip across each other. Soft x-ray observations of fast bidirectional motions of coronal loops, observed by the Hinode spacecraft, support the existence of this slipping magnetic reconnection regime in the Sun's corona. This basic process should be considered when interpreting reconnection, both on the Sun and in laboratory-based plasma experiments.

  11. Estudio antropológico de redes sociales de madres adolescentes durante el embarazo. En: Avá, nº 14

    OpenAIRE

    Pasarin, Lorena

    2008-01-01

    La atención de la salud incluye a diversos actores sociales, por ello en su estudio debe contemplarse el papel que adquieren los contextos socioculturales. El estudio de las redes sociales resulta conveniente para abordarlos. Este trabajo presenta una aplicación del análisis de redes sociales como complemento de abordaje metodológico al estudio de las prácticas y comportamientos relacionados con la salud de madres adolescentes durante el período prenatal. Utilizando la herramienta E...

  12. Observational Consequences of Coronal Heating Mechanisms

    Science.gov (United States)

    Winebarger, Amy R.; Cirtain, Jonathan C.; Golub, Leon; Kobayashi, Ken

    2014-01-01

    The coronal heating problem remains unsolved today, 80 years after its discovery, despite 50 years of suborbital and orbital coronal observatories. Tens of theoretical coronal heating mechanisms have been suggested, but only a few have been able to be ruled out. In this talk, we will explore the reasons for the slow progress and discuss the measurements that will be needed for potential breakthrough, including imaging the solar corona at small spatial scales, measuring the chromospheric magnetic fields, and detecting the presence of high temperature, low emission measure plasma. We will discuss three sounding rocket instruments developed to make these measurements: the High resolution Resolution Coronal Imager (Hi-C), the Chromospheric Lyman-Alpha Spectropolarimeter (CLASP), and the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS).

  13. Multidimensional modeling of coronal rain dynamics

    CERN Document Server

    Fang, X; Keppens, R

    2013-01-01

    We present the first multidimensional, magnetohydrodynamic simulations which capture the initial formation and the long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in-situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match with modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into $V$-shaped like features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views on blobs which evaporate in situ, or get siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys o...

  14. Microwave Enhancement in Coronal Holes: Statistical Properties

    Indian Academy of Sciences (India)

    Ν. Gopalswamy; Κ. Shibasaki; Μ. Salem

    2000-09-01

    We report on the statistical properties of the microwave enhancement (brightness temperature, area, fine structure, life time and magnetic field strength) in coronal holes observed over a period of several solar rotations.

  15. Relating magnetic reconnection to coronal heating.

    Science.gov (United States)

    Longcope, D W; Tarr, L A

    2015-05-28

    It is clear that the solar corona is being heated and that coronal magnetic fields undergo reconnection all the time. Here we attempt to show that these two facts are related--i.e. coronal reconnection generates heat. This attempt must address the fact that topological change of field lines does not automatically generate heat. We present one case of flux emergence where we have measured the rate of coronal magnetic reconnection and the rate of energy dissipation in the corona. The ratio of these two, [Formula: see text], is a current comparable to the amount of current expected to flow along the boundary separating the emerged flux from the pre-existing flux overlying it. We can generalize this relation to the overall corona in quiet Sun or in active regions. Doing so yields estimates for the contribution to coronal heating from magnetic reconnection. These estimated rates are comparable to the amount required to maintain the corona at its observed temperature.

  16. Coronal Magnetism and Forward Solarsoft Idl Package

    Science.gov (United States)

    Gibson, S. E.

    2014-12-01

    The FORWARD suite of Solar Soft IDL codes is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD may be used both to synthesize a broad range of coronal observables, and to access and compare to existing data. FORWARD works with numerical model datacubes, interfaces with the web-served Predictive Science Inc MAS simulation datacubes and the Solar Soft IDL Potential Field Source Surface (PFSS) package, and also includes several analytic models (more can be added). It connects to the Virtual Solar Observatory and other web-served observations to download data in a format directly comparable to model predictions. It utilizes the CHIANTI database in modeling UV/EUV lines, and links to the CLE polarimetry synthesis code for forbidden coronal lines. FORWARD enables "forward-fitting" of specific observations, and helps to build intuition into how the physical properties of coronal magnetic structures translate to observable properties.

  17. Observational Properties of Coronal Mass Ejections

    Science.gov (United States)

    2006-01-01

    2003. Peameis, D.V., Magntetic topology of imspumlsive assd gradutal solar energetic particle Xic. H., L. Ofmran, and G. Lawvrence, Cone model for...425, 1097, 2004. Yashiro, S., N. Gopalssvamy, G. Michalek, assd R.A. Hosvard, Properties of narrow coronal Sltatstnigara~jU, A., Y.-i. Mootn, M. Dryer...G.M.,’FTit relatiomtslip hetwseen prominence ermtptions assd coronal mnass ejections.. 107(A8), 1223, doi: 10. 1029/2001 JAOO9 143, 2002. .1. Atssnn.s

  18. Observational features of equatorial coronal hole jets

    CERN Document Server

    Nistico', G; Patsourakos, S; Zimbardo, G

    2010-01-01

    Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet events are selected by requiring at least some visibility in both COR1 and EUVI instruments. We report 15 jet events, and we discuss their main features. For one event, the uplift velocity has been determined as about 200 km/s, while the deceleration rate appears to be about 0.11 km/s2, less than solar gravity. The average jet visibility time is about 30 minutes, consistent with jet observed in polar regions. On the basis of the present dataset, we provisionally conclude that there are not substantial physical differences between polar and eq...

  19. MULTIDIMENSIONAL MODELING OF CORONAL RAIN DYNAMICS

    Energy Technology Data Exchange (ETDEWEB)

    Fang, X.; Xia, C.; Keppens, R. [Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, B-3001 Leuven (Belgium)

    2013-07-10

    We present the first multidimensional, magnetohydrodynamic simulations that capture the initial formation and long-term sustainment of the enigmatic coronal rain phenomenon. We demonstrate how thermal instability can induce a spectacular display of in situ forming blob-like condensations which then start their intimate ballet on top of initially linear force-free arcades. Our magnetic arcades host a chromospheric, transition region, and coronal plasma. Following coronal rain dynamics for over 80 minutes of physical time, we collect enough statistics to quantify blob widths, lengths, velocity distributions, and other characteristics which directly match modern observational knowledge. Our virtual coronal rain displays the deformation of blobs into V-shaped features, interactions of blobs due to mostly pressure-mediated levitations, and gives the first views of blobs that evaporate in situ or are siphoned over the apex of the background arcade. Our simulations pave the way for systematic surveys of coronal rain showers in true multidimensional settings to connect parameterized heating prescriptions with rain statistics, ultimately allowing us to quantify the coronal heating input.

  20. An Estimate of Solar Wind Density and Velocity Profiles in a Coronal Hole and a Coronal Streamer

    Science.gov (United States)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1996-01-01

    Using the total electron content data obtained by the Ulysses Solar Corona Experiment (SCE) during the first solar conjunction in summer 1991, two data sets were selected, one associated with a coronal hole and the other associated with coronal streamer crossings. In order to determine coronal streamer density profiles, the electron content of the tracking passes embedded in a coronal streamer were corrected for the contributions from coronal hole densities.

  1. PARATIROIDECTOMIA ENDOSCOPICA. ESTUDIO EXPERIMENTAL EN EL PERRO

    Directory of Open Access Journals (Sweden)

    Jorge Ramón Lucena Olavarrieta

    2008-01-01

    Full Text Available La primera paratiroidectomía exitosa fue realizada en Viena, Austria, en 1925. Los procedimientos laparoscópicos estuvieron inicialmente limitadas a las zonas corporales con cavidades preexistentes, recientemente, el acceso a espacios anatómicos potenciales ha extendido las indicaciones de la cirugía endoscópica minimamnete invasiva.Desde el primer reporte sobre la paratiroidectomía endoscópica en 1996, las técnicas video-asistidas han comenzado a utilizarse en la cirugía del cuello, y en varias series se han documentado la factibilidad y seguridad de este tipo de abordaje. La finalidad de esta investigación fue el determinar la factibilidad, seguridad y eficacia de la paratiroidectomía endoscopia en el modelo canino.Entre el 25 de noviembre del 2005 y 15 de octubre del 2007, se intervinieron en el Instituto de Cirugía Experimental de la Universidad Central de Venezuela 31 perros, mestizos sanos desparasitados,asignándose a dos grupos: homogéneos "A" 16, a cirugía convencional, "B" 15 a cirugía video-asistida. Se midieron las siguientes variables; sexo, peso, exámenes de laboratorio, laringoscopia pre y postoperatoria, posición, dirección de la incisión, longitud, localización, valores pre y postoperatorios de calcio, fósforo, proteína C reactiva, hemoglobina, hematocrito, tipo de disección, número y posición de las paratiroides, identificación de los nervios recurrentes y rama externa del nervio laríngeo superior, sangramiento, dificultades intraoperatorias, tiempo, resultado del estudio histopatológico.Las deducciones de este estudio experimental proporcionan evidencias de que la paratiroidectomía endoscópica es factible y segura. El abordaje mínimo tiene mejores resultados cosméticos y el potencial de disminuir la morbi-mortalidad.

  2. Abordaje de la artrosis desde la atención primaria

    OpenAIRE

    Lafuente Navarro, Ana; Lafuente Navarro, Cándida

    2006-01-01

    La artrosis es una enfermedad crónica prevalente asociada a dolor, discapacidad y empeoramiento de la calidad de vida. Las herramientas de apoyo que utilizamos a menudo en atención primaria para el abordaje de esta patología son las guías de la práctica clínica. En estas guías hay recomendaciones basadas en la evidencia,que ayudan al profesional en su práctica habitual a tomar la decisión más adecuada para cada paciente. A su vez permiten actuar de una forma conjunta y sincronizada a los dife...

  3. Abordaje médico forense de los cuerpos mutilados criminalmente

    OpenAIRE

    José Vicente Pachar Lucio

    2015-01-01

    La mutilación post-mórtem de un cadáver es una forma criminal de separación de las partes corporales que responde a diversas motivaciones. El abordaje adecuado, desde el lugar del hallazgo hasta el examen en la morgue, es fundamental para la recolección de los indicios que permitan la reconstrucción del hecho investigado. Los métodos e instrumentos utilizados para la mutilación han sido descritos por investigadores de distintos países; sin embargo, las motivaciones mencionadas en la literatur...

  4. Abordaje interdisciplinario de tres hermanas con Amelogénesis imperfecta: Reporte de Caso

    OpenAIRE

    Brenes A., Alejandra; Montero S., Olman

    2011-01-01

    Tres hermanas con edades de 7, 9 y 12 años fueron atendidas en la clínica del Posgrado de Odontopediatría de la Universidad de Costa Rica; ellas presentaban amelogénesis imperfecta tipo hipoplásico y mordida abierta anterior. La higiene bucodental en las tres, era muy deficiente, lo que obligó el abordaje con sesiones de fase higiénica que permitieran posteriormente, iniciar el tratamiento rehabilitador. Cada caso fue estudiado en forma independiente. Se hizo necesario proceder interdisciplin...

  5. Coronal "wave": Magnetic Footprint Of A Cme?

    Science.gov (United States)

    Attrill, Gemma; Harra, L. K.; van Driel-Gesztelyi, L.; Demoulin, P.; Wuelser, J.

    2007-05-01

    We propose a new mechanism for the generation of "EUV coronal waves". This work is based on new analysis of data from SOHO/EIT, SOHO/MDI & STEREO/EUVI. Although first observed in 1997, the interpretation of coronal waves as flare-induced or CME-driven remains a debated topic. We investigate the properties of two "classical" SOHO/EIT coronal waves in detail. The source regions of the associated CMEs possess opposite helicities & the coronal waves display rotations in opposite senses. We observe deep dimmings near the flare site & also widespread diffuse dimming, accompanying the expansion of the EIT wave. We report a new property of these EIT waves, namely, that they display dual brightenings: persistent ones at the outermost edge of the core dimming regions & simultaneously diffuse brightenings constituting the leading edge of the coronal wave, surrounding the expanding diffuse dimmings. We show that such behaviour is consistent with a diffuse EIT wave being the magnetic footprint of a CME. We propose a new mechanism where driven magnetic reconnections between the skirt of the expanding CME & quiet-Sun magnetic loops generate the observed bright diffuse front. The dual brightenings & widespread diffuse dimming are identified as innate characteristics of this process. In addition we present some of the first analysis of a STEREO/EUVI limb coronal wave. We show how the evolution of the diffuse bright front & dimmings can be understood in terms of the model described above. We show that an apparently stationary part of the bright front can be understood in terms of magnetic interchange reconnections between the expanding CME & the "open" magnetic field of a low-latitude coronal hole. We use both the SOHO/EIT & STEREO/EUVI events to demonstrate that through successive reconnections, this new model provides a natural mechanism via which CMEs can become large-scale in the lower corona.

  6. La entrevista colectiva como dispositivo para el abordaje transdisciplinar de la identidad socioterritorial. Un acercamiento desde la mirada decolonial

    Directory of Open Access Journals (Sweden)

    Martín Segovia Stanoss

    2015-04-01

    Full Text Available Hacia finales del siglo XX, se produce el reingreso del testimonio oral como fuente para la producción de conocimiento histórico, y de la Memoria al universo de la Historia como vía de acceso al imaginario de los sujetos; ello significó la posibilidad de dar cuenta de la multiplicidad de filiaciones identitarias mantenidas “al margen”, antes silenciadas, que pueden activarse en los sujetos en atención al “otro” en confrontación al cual se construye.La recuperación de las escalas de abordaje microsociales -lo local, lo barrial-, indispensable para el propósito de comprensión de los fenómenos culturales/simbólicos, permitió la organización de nuevos campos cuya adscripción disciplinar resulta dificultosamente definida.En este marco se involucran los estudios que abordan los mecanismos que contribuyen a la construcción de identidades socioterritoriales -a escala intraurbana- utilizando relatos biográficos y observando el espacio que los acontecimientos recordados ocupan en el establecimiento de relaciones simbólicas con el territorio habitado.Con los propósitos señalados, y a partir de una experiencia concreta, se propone la reflexión desde una matriz transdisciplinar sobre los alcances y limitaciones de la instancia de entrevista grupal como espacio de participación comunitaria y dispositivo de co-construcción de datos.Como resultado, se dispone de una mirada metodológica ampliada hacia dimensiones epistemológicas, que asisten a las reacciones que enfrentan tanto los acercamientos ingenuos que pretenden una suerte de desaparición del investigador para dar voz al “otro”, como los que asumen que el investigador interpreta las interpretaciones de los entrevistados desde una posición privilegiada y distante.

  7. Cavernomas de la región temporal mesial: Anatomía microquirúrgica y abordajes

    Science.gov (United States)

    Campero, Alvaro

    2015-01-01

    Objetivo: Describir la anatomía microquirúrgica y los abordajes a la región temporal mesial (RTM), en relación a cavernomas de dicho sector. Materiales y Método: Cinco cabezas de cadáveres adultos, fijadas en formol e inyectadas con silicona coloreada, fueron estudiadas. Además, desde enero de 2007 a junio de 2014, 7 pacientes con cavernomas localizados en la RTM fueron operados por el autor. Resultados: Anatomia: La RTM fue dividida en 3 sectores: Anterior, medio y posterior. Pacientes: 7 enfermos con cavernomas de la RTM fueron operados por el autor. De acuerdo a la ubicacion en la RTM, 4 cavernomas se ubicaron en el sector anterior, 2 cavernomas se localizaron en el sector medio y 1 cavernoma se ubico en el sector posterior. Para el sector anterior de la RTM se utilizo un abordaje transsilviano-transinsular; para el sector medio de la RTM se utilizo un abordaje transtemporal (lobectomia temporal anterior); y para el sector posterior de la RTM se utilizo un abordaje supracerebeloso-transtentorial. Conclusión: Dividir la RTM en 3 sectores nos permite adecuar el abordaje en función a la localización de la lesión. Así, el sector anterior es bien abordable a través de la fisura silviana; el sector medio a través de una vía transtemporal; y el sector posterior por un abordaje supracerebeloso. PMID:26600986

  8. Abordaje médico forense de los cuerpos mutilados criminalmente

    Directory of Open Access Journals (Sweden)

    José Vicente Pachar Lucio

    2015-12-01

    Full Text Available La mutilación post-mórtem de un cadáver es una forma criminal de separación de las partes corporales que responde a diversas motivaciones. El abordaje adecuado, desde el lugar del hallazgo hasta el examen en la morgue, es fundamental para la recolección de los indicios que permitan la reconstrucción del hecho investigado. Los métodos e instrumentos utilizados para la mutilación han sido descritos por investigadores de distintos países; sin embargo, las motivaciones mencionadas en la literatura sobre la mutilación deben ser ampliadas ante la complejidad de los casos encontrados en la región (Centroamérica y México. Se realiza una revisión descriptiva de lo publicado sobre el tema, con el propósito de actualizar conceptos útiles en la práctica médico forense, elementos que deben estar disponibles para el abordaje e interpretación de los hallazgos. Además se presenta un modelo de protocolo de actuación médico forense, específico para estos casos.

  9. Ectopic folliculosebaceous units at the coronal sulcus.

    Science.gov (United States)

    Fernandez-Flores, Angel

    2014-12-01

    Tyson glands were described in the 17th century as modified sebaceous glands of the coronal sulcus of the penis. However, this description and other early texts supporting the existence of Tyson glands were not accompanied by illustrations. The existence of such glands has been passing through the literature without adequate graphical demonstration, which has contributed to controversial debates. Herein we present a case of a partial penectomy performed on a 65-year-old man with a squamous cell carcinoma of the penis. In this case we identified sebaceous glands as well as folliculosebaceous units in the coronal sulcus. We also comparatively examined 12 cases of partial penectomy to search for sebaceous glands or folliculosebaceous units in the coronal sulcus or the preputium. We found neither sebaceous glands nor folliculosebaceous units at the coronal sulcus or the mucosal aspect of the prepuce. We conclude that: (1) folliculosebaceous units are possible in the coronal sulcus, as the current case illustrates for the first time in literature and (2) the current case is an oddity, probably induced by the accompanying squamous cell carcinoma, and therefore it may represent an ectopic folliculosebaceous unit rather than an anatomic variation.

  10. DIRECT OBSERVATION OF SOLAR CORONAL MAGNETIC FIELDS BY VECTOR TOMOGRAPHY OF THE CORONAL EMISSION LINE POLARIZATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Kramar, M. [Physics Department, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 (United States); Lin, H. [Institute for Astronomy, University of Hawaii at Manoa, 34 Ohia Ku Street, Pukalani, Maui, HI 96768 (United States); Tomczyk, S., E-mail: kramar@cua.edu, E-mail: lin@ifa.hawaii.edu, E-mail: tomczyk@ucar.edu [High Altitude Observatory, 3080 Center Green Drive, Boulder, CO 80301 (United States)

    2016-03-10

    We present the first direct “observation” of the global-scale, 3D coronal magnetic fields of Carrington Rotation (CR) Cycle 2112 using vector tomographic inversion techniques. The vector tomographic inversion uses measurements of the Fe xiii 10747 Å Hanle effect polarization signals by the Coronal Multichannel Polarimeter (CoMP) and 3D coronal density and temperature derived from scalar tomographic inversion of Solar Terrestrial Relations Observatory (STEREO)/Extreme Ultraviolet Imager (EUVI) coronal emission lines (CELs) intensity images as inputs to derive a coronal magnetic field model that best reproduces the observed polarization signals. While independent verifications of the vector tomography results cannot be performed, we compared the tomography inverted coronal magnetic fields with those constructed by magnetohydrodynamic (MHD) simulations based on observed photospheric magnetic fields of CR 2112 and 2113. We found that the MHD model for CR 2112 is qualitatively consistent with the tomography inverted result for most of the reconstruction domain except for several regions. Particularly, for one of the most noticeable regions, we found that the MHD simulation for CR 2113 predicted a model that more closely resembles the vector tomography inverted magnetic fields. In another case, our tomographic reconstruction predicted an open magnetic field at a region where a coronal hole can be seen directly from a STEREO-B/EUVI image. We discuss the utilities and limitations of the tomographic inversion technique, and present ideas for future developments.

  11. Free Magnetic Energy and Coronal Heating

    Science.gov (United States)

    Winebarger, Amy; Moore, Ron; Falconer, David

    2012-01-01

    Previous work has shown that the coronal X-ray luminosity of an active region increases roughly in direct proportion to the total photospheric flux of the active region's magnetic field (Fisher et al. 1998). It is also observed, however, that the coronal luminosity of active regions of nearly the same flux content can differ by an order of magnitude. In this presentation, we analyze 10 active regions with roughly the same total magnetic flux. We first determine several coronal properties, such as X-ray luminosity (calculated using Hinode XRT), peak temperature (calculated using Hinode EIS), and total Fe XVIII emission (calculated using SDO AIA). We present the dependence of these properties on a proxy of the free magnetic energy of the active region

  12. A Contemporary View of Coronal Heating

    CERN Document Server

    Parnell, Clare E; 10.1098/rsta.2012.0113

    2012-01-01

    Determining the heating mechanism (or mechanisms) that causes the outer atmosphere of the Sun, and many other stars, to reach temperatures orders of magnitude higher than their surface temperatures has long been a key problem. For decades the problem has been known as the coronal heating problem, but it is now clear that `coronal heating' cannot be treated or explained in isolation and that the heating of the whole solar atmosphere must be studied as a highly coupled system. The magnetic field of the star is known to play a key role, but, despite significant advancements in solar telescopes, computing power and much greater understanding of theoretical mechanisms, the question of which mechanism or mechanisms are the dominant supplier of energy to the chromosphere and corona is still open. Following substantial recent progress, we consider the most likely contenders and discuss the key factors that have made, and still make, determining the actual (coronal) heating mechanism (or mechanisms) so difficult.

  13. Coronal heating in multiple magnetic threads

    CERN Document Server

    Tam, K V; Browning, P K; Cargill, P J

    2015-01-01

    Context. Heating the solar corona to several million degrees requires the conversion of magnetic energy into thermal energy. In this paper, we investigate whether an unstable magnetic thread within a coronal loop can destabilise a neighbouring magnetic thread. Aims. By running a series of simulations, we aim to understand under what conditions the destabilisation of a single magnetic thread can also trigger a release of energy in a nearby thread. Methods. The 3D magnetohydrodynamics code, Lare3d, is used to simulate the temporal evolution of coronal magnetic fields during a kink instability and the subsequent relaxation process. We assume that a coronal magnetic loop consists of non-potential magnetic threads that are initially in an equilibrium state. Results. The non-linear kink instability in one magnetic thread forms a helical current sheet and initiates magnetic reconnection. The current sheet fragments, and magnetic energy is released throughout that thread. We find that, under certain conditions, this ...

  14. A unified theory of coronal heating

    Science.gov (United States)

    Ionson, J. A.

    1985-01-01

    Solar coronal heating mechanisms are analyzed within the framework of a unified theory of heating processes. The theory is based on the standing wave equation of Ionson (1982) for the global current driven by emfs from the convection Beta less than 1. The equation has the same form as a driven LRC equation in which the equivalent inductance is scaled with the coronal loop length. The theory is used to classify various heating mechanisms inside the coronal loops. It is shown that the total global current can be obtained from an integration of the local currents, the degree of coherency between local currents being the dominant factor governing the global current amplitude. Active region loops appear to be heated by electrodynamic coupling to p-mode oscillations in the convection Beta less than 1.

  15. The Fundamental Structure of Coronal Loops

    Science.gov (United States)

    Winebarger, Amy; Warren, Harry; Cirtain, Jonathan; Kobayashi, Ken; Korreck, Kelly; Golub, Leon; Kuzin, Sergey; Walsh, Robert; DePontieu, Bart; Title, Alan; Weber, Mark

    2012-01-01

    During the past ten years, solar physicists have attempted to infer the coronal heating mechanism by comparing observations of coronal loops with hydrodynamic model predictions. These comparisons often used the addition of sub ]resolution strands to explain the observed loop properties. On July 11, 2012, the High Resolution Coronal Imager (Hi ]C) was launched on a sounding rocket. This instrument obtained images of the solar corona was 0.2 ]0.3'' resolution in a narrowband EUV filter centered around 193 Angstroms. In this talk, we will compare these high resolution images to simultaneous density measurements obtained with the Extreme Ultraviolet Imaging Spectrograph (EIS) on Hinode to determine whether the structures observed with Hi ]C are resolved.

  16. Magnetohydrodynamic Modeling of Coronal Evolution and Disruption

    Science.gov (United States)

    Linker, Jon

    2002-01-01

    Flux cancellation, defined observationally as the mutual disappearance of magnetic fields of opposite polarity at the neutral line separating them, has been found to occur frequently at the site of filaments (called prominences when observed on the limb of the Sun). During the second year of this project, we have studied theoretically the role that flux cancellation may play in prominence formation, prominence eruption, and the initiation of coronal mass ejections. This work has been in published in two papers: "Magnetic Field Topology in Prominences" by Lionello, Mikic, Linker, and Amari and "Flux Cancellation and Coronal Mass Ejections" by Linker, Mikic, Riley, Lionello, Amari, and Odstrcil.

  17. Las neurociencias para el abordaje de la didáctica de las finanzas

    OpenAIRE

    Florentino Rico Calvano; Pedro Puentes Rozo

    2016-01-01

    El presente artículo de revisión se centra en determinar cuál es el discurso de las neurociencias para el abordaje de la didáctica de las finanzas, y cuáles son las estrategias y didácticas aplicadas a la enseñabilidad de las finanzas y su correspondencia con la práctica y los modelos pedagógicos. Se identificaron teorías didácticas que fundamentarán las prácticas educativas de los docentes en la enseñabilidad, evaluando, articulando y confrontando los fundamentos pedagógicos que poseen los d...

  18. Diversidad juvenil en el contexto educativo: reflexiones para un abordaje intercultural

    Directory of Open Access Journals (Sweden)

    Morales-Trejos, Carol Graciela

    2015-01-01

    Full Text Available Este ensayo enmarca la relevancia teórico-práctica de la educación intercultural, como herramienta para generar nuevas lecturas de la complejidad educativa, donde la diversidad sea comprendida como una oportunidad de aprendizaje y de riqueza, promoviendo el desarrollo de contextos educativos más heterogéneos y equitativos. Se aborda el tema de la diversidad juvenil en este contexto desde la perspectiva intercultural. Finalmente se realiza una propuesta de abordaje de esta temática desde los aportes de este enfoque educativo, reconociendo la multiplicidad de factores que configuran los mundos juveniles, las nuevas formas de interacción y la construcción de identidades individuales y colectivas.

  19. DIVERSIDAD JUVENIL EN EL CONTEXTO EDUCATIVO: REFLEXIONES PARA UN ABORDAJE INTERCULTURAL

    Directory of Open Access Journals (Sweden)

    Carol Graciela Morales-Trejos

    2015-01-01

    Full Text Available Este ensayo enmarca la relevancia teórico-práctica de la educación intercultural, como herramienta para generar nuevas lecturas de la complejidad educativa, donde la diversidad sea comprendida como una oportunidad de aprendizaje y de riqueza, promoviendo el desarrollo de contextos educativos más heterogéneos y equitativos. Se aborda el tema de la diversidad juvenil en este contexto desde la perspectiva intercultural. Finalmente se realiza una propuesta de abordaje de esta temática desde los aportes de este enfoque educativo, reconociendo la multiplicidad de factores que configuran los mundos juveniles, las nuevas formas de interacción y la construcción de identidades individuales y colectivas.

  20. Tiroides lingual: un nuevo abordaje quirúrgico Lingual thyroid: a new surgical approach

    Directory of Open Access Journals (Sweden)

    I. Zubillaga Rodríguez

    2004-10-01

    Full Text Available El tiroides lingual es una rara anomalía congénita del desarrollo tiroideo resultante de la ausencia de descenso del mismo desde el foramen caecum hasta la localización prelaríngea habitual. Presentamos el caso de una paciente en edad postmenopáusica con diagnóstico anatomopatológico de tiroides lingual de gran tamaño y localización profunda en la base de la lengua que producía disfagia y dificultad respiratoria crecientes. Asimismo, planteamos un nuevo abordaje quirúrgico para la resección combinando cervicotomía media, pull-through lingual y glosotomía media. Se discuten las distintas pruebas complementarias para llegar a su diagnóstico y se revisan las diferentes técnicas quirúrgicas habitualmente empleadas en su tratamiento concluyendo con las ventajas del abordaje empleado en este caso.Lingual thyroid is an uncommon congenital disorder of thyroid gland development, resulting in a lack of descend of the gland from the foramen caecum to his normal prelaringeal location. In this paper we present a case of a postmenopausic patient presenting with a big size lingual thyroid deeply located in the base of the tongue, suffering increasing disphagia and respiratory impairment. For tumor resection, we chose a surgical approach combining a cervical submental incision, lingual pull- through and midline glossotomy. We discuss the different image studies recommended for proper diagnosis also reviewing the most common surgical techniques used for treatment, as compared with the approach we have described in this case.

  1. Entre la gestión del riesgo y el abordaje psicosocial

    Directory of Open Access Journals (Sweden)

    Matamoros Calvo, María Cristina

    2013-06-01

    Full Text Available El trabajo en la gestión para la reducción del riesgo por desastres, contempla diferentes elementos dentro de su estrategia, muchos de ellos de contenido técnico y otros de índole social; y para su ejecución y cumplimiento de los objetivos se requiere de esfuerzos interdisciplinarios, para poder hacer abordajes integrales. Por tanto, en este escrito se pretende hacer una reflexión en torno a la relación entre la gestión del riesgo y el aporte de la psicología como ciencia social, llamando desde ahí la atención sobre la importancia de considerar el factor psicosocial en las estrategias de reducción del riesgo. Para lo cual se hace un recorrido desde la concepción de la psicología, de la gestión del riesgo, para finalmente arribar a una mirada integradora como propuesta en el abordaje del riesgo, de las emergencias y los desastres The work in management to reduce the risk by disasters, includes different elements within the strategy, most of them of technical content and others of social nature. For the execution and compliance of the objectives, it is necessary to have interdisciplinary efforts to apply integral focus. In this context, this work tries to reflect around the relation between risks management and the contribution of psychology as a social science, emphasizing the importance of considering the psychosocial factor in the risk reduction strategies. For this, there is a walk from the conception of psychology to the risk management, to finally arrive at an integral gaze as a proposal to the risk approach for emergencies and disasters

  2. Coronal temperature profiles obtained from kinetic models and from coronal brightness measurements obtained during solar eclipses

    CERN Document Server

    Pierrard, V; Lemaire, J F

    2012-01-01

    Coronal density, temperature and heat flux distributions for the equatorial and polar corona have been deduced by Lemaire [2012] from Saito's model of averaged coronal white light (WL) brightness and polarization observations. They are compared with those determined from a kinetic collisionless/exospheric model of the solar corona. This comparison indicates rather similar distributions at large radial distances (> 7 Rs) in the collisionless region. However, rather important differences are found close to the Sun in the acceleration region of the solar wind. The exospheric heat flux is directed away from the Sun, while that inferred from all WL coronal observations is in the opposite direction, i.e., conducting heat from the inner corona toward the chromosphere. This could indicate that the source of coronal heating rate extends up into the inner corona where it maximizes at r > 1.5 Rs well above the transition region.

  3. Large-scale Globally Propagating Coronal Waves

    Directory of Open Access Journals (Sweden)

    Alexander Warmuth

    2015-09-01

    Full Text Available Large-scale, globally propagating wave-like disturbances have been observed in the solar chromosphere and by inference in the corona since the 1960s. However, detailed analysis of these phenomena has only been conducted since the late 1990s. This was prompted by the availability of high-cadence coronal imaging data from numerous spaced-based instruments, which routinely show spectacular globally propagating bright fronts. Coronal waves, as these perturbations are usually referred to, have now been observed in a wide range of spectral channels, yielding a wealth of information. Many findings have supported the “classical” interpretation of the disturbances: fast-mode MHD waves or shocks that are propagating in the solar corona. However, observations that seemed inconsistent with this picture have stimulated the development of alternative models in which “pseudo waves” are generated by magnetic reconfiguration in the framework of an expanding coronal mass ejection. This has resulted in a vigorous debate on the physical nature of these disturbances. This review focuses on demonstrating how the numerous observational findings of the last one and a half decades can be used to constrain our models of large-scale coronal waves, and how a coherent physical understanding of these disturbances is finally emerging.

  4. Coronal bright points associated with minifilament eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Bi, Yi; Li, Haidong [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Yang, Bo; Yang, Dan, E-mail: hjcsolar@ynao.ac.cn [Also at Graduate School of Chinese Academy of Sciences, Beijing, China. (China)

    2014-12-01

    Coronal bright points (CBPs) are small-scale, long-lived coronal brightenings that always correspond to photospheric network magnetic features of opposite polarity. In this paper, we subjectively adopt 30 CBPs in a coronal hole to study their eruptive behavior using data from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory. About one-quarter to one-third of the CBPs in the coronal hole go through one or more minifilament eruption(s) (MFE(s)) throughout their lifetimes. The MFEs occur in temporal association with the brightness maxima of CBPs and possibly result from the convergence and cancellation of underlying magnetic dipoles. Two examples of CBPs with MFEs are analyzed in detail, where minifilaments appear as dark features of a cool channel that divide the CBPs along the neutral lines of the dipoles beneath. The MFEs show the typical rising movements of filaments and mass ejections with brightenings at CBPs, similar to large-scale filament eruptions. Via differential emission measure analysis, it is found that CBPs are heated dramatically by their MFEs and the ejected plasmas in the MFEs have average temperatures close to the pre-eruption BP plasmas and electron densities typically near 10{sup 9} cm{sup –3}. These new observational results indicate that CBPs are more complex in dynamical evolution and magnetic structure than previously thought.

  5. Observing coronal nanoflares in active region moss

    CERN Document Server

    Testa, Paola; Martinez-Sykora, Juan; DeLuca, Ed; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Golub, Leon; Kobayashi, Ken; Korreck, Kelly; Kuzin, Sergey; Walsh, Robert; DeForest, Craig; Title, Alan; Weber, Mark

    2013-01-01

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial (~0.3-0.4 arcsec) and temporal (5.5s) resolution. The Hi-C observations show in some moss regions variability on timescales down to ~15s, significantly shorter than the minute scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by SDO/AIA in the 94A channel, and by Hinode/XRT. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few $10^{23}rg, also supporting the nanoflare scenario. These Hi-C...

  6. OBSERVING CORONAL NANOFLARES IN ACTIVE REGION MOSS

    Energy Technology Data Exchange (ETDEWEB)

    Testa, Paola; DeLuca, Ed; Golub, Leon; Korreck, Kelly; Weber, Mark [Smithsonian Astrophysical Observatory, 60 Garden street, MS 58, Cambridge, MA 02138 (United States); De Pontieu, Bart; Martinez-Sykora, Juan; Title, Alan [Lockheed Martin Solar and Astrophysics Lab, Org. A021S, Bldg. 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Hansteen, Viggo [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway); Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Kuzin, Sergey [P. N. Lebedev Physical institute of the Russian Academy of Sciences, Leninskii prospekt, 53, 119991 Moscow (Russian Federation); Walsh, Robert [University of Central Lancashire, Lancashire, Preston PR1 2HE (United Kingdom); DeForest, Craig, E-mail: ptesta@cfa.harvard.edu [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2013-06-10

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial ({approx}0.''3-0.''4) and temporal (5.5 s) resolution. The Hi-C observations show in some moss regions variability on timescales down to {approx}15 s, significantly shorter than the minute-scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly in the 94 A channel, and by the Hinode/X-Ray Telescope. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few 10{sup 23} erg, also supporting the nanoflare scenario. These Hi-C observations suggest that future observations at comparable high spatial and temporal resolution, with more extensive temperature coverage, are required to determine the exact characteristics of the heating mechanism(s).

  7. Magnetic Topology of Coronal Hole Linkages

    Science.gov (United States)

    Titov, V. S.; Mikic, Z.; Linker, J. A.; Lionello, R.; Antiochos, S. K.

    2010-01-01

    In recent work, Antiochos and coworkers argued that the boundary between the open and closed field regions on the Sun can be extremely complex with narrow corridors of open ux connecting seemingly disconnected coronal holes from the main polar holes, and that these corridors may be the sources of the slow solar wind. We examine, in detail, the topology of such magnetic configurations using an analytical source surface model that allows for analysis of the eld with arbitrary resolution. Our analysis reveals three important new results: First, a coronal hole boundary can join stably to the separatrix boundary of a parasitic polarity region. Second, a single parasitic polarity region can produce multiple null points in the corona and, more important, separator lines connecting these points. Such topologies are extremely favorable for magnetic reconnection, because it can now occur over the entire length of the separators rather than being con ned to a small region around the nulls. Finally, the coronal holes are not connected by an open- eld corridor of finite width, but instead are linked by a singular line that coincides with the separatrix footprint of the parasitic polarity. We investigate how the topological features described above evolve in response to motion of the parasitic polarity region. The implications of our results for the sources of the slow solar wind and for coronal and heliospheric observations are discussed.

  8. Role of Magnetic Carpet in Coronal Heating

    Indian Academy of Sciences (India)

    S. R. Verma; Diksha Chaudhary

    2008-03-01

    One of the fundamental questions in solar physics is how the solar corona maintains its high temperature of several million Kelvin above photosphere with a temperature of 6000 K. Observations show that solar coronal heating problem is highly complex with many different facts. It is likely that different heating mechanisms are at work in the solar corona. The separate kinds of coronal loops may also be heated by different mechanisms. Using data from instruments onboard the Solar and Heliospheric Observatory (SOHO) and from the more recent Transition Region and Coronal Explorer (TRACE) scientists have identified small regions of mixed polarity, termed magnetic carpet contributing to solar activity on a short time scale. Magnetic loops of all sizes rise into the solar corona, arising from regions of opposite magnetic polarity in the photosphere. Energy released when oppositely directed magnetic fields meet in the corona is one likely cause for coronal heating. There is enough energy coming up from the loops of the “magnetic carpet” to heat the corona to its known temperature.

  9. Genesis Solar Wind Interstream, Coronal Hole and Coronal Mass Ejection Samples: Update on Availability and Condition

    Science.gov (United States)

    Allton, J. H.; Gonzalez, C. P.; Allums, K. K.

    2017-01-01

    Recent refinement of analysis of ACE/SWICS data (Advanced Composition Explorer/Solar Wind Ion Composition Spectrometer) and of onboard data for Genesis Discovery Mission of 3 regimes of solar wind at Earth-Sun L1 make it an appropriate time to update the availability and condition of Genesis samples specifically collected in these three regimes and currently curated at Johnson Space Center. ACE/SWICS spacecraft data indicate that solar wind flow types emanating from the interstream regions, from coronal holes and from coronal mass ejections are elementally and isotopically fractionated in different ways from the solar photosphere, and that correction of solar wind values to photosphere values is non-trivial. Returned Genesis solar wind samples captured very different kinds of information about these three regimes than spacecraft data. Samples were collected from 11/30/2001 to 4/1/2004 on the declining phase of solar cycle 23. Meshik, et al is an example of precision attainable. Earlier high precision laboratory analyses of noble gases collected in the interstream, coronal hole and coronal mass ejection regimes speak to degree of fractionation in solar wind formation and models that laboratory data support. The current availability and condition of samples captured on collector plates during interstream slow solar wind, coronal hole high speed solar wind and coronal mass ejections are de-scribed here for potential users of these samples.

  10. Using coronal seismology to estimate the magnetic field strength in a realistic coronal model

    CERN Document Server

    Chen, Feng

    2015-01-01

    Coronal seismology is extensively used to estimate properties of the corona, e.g. the coronal magnetic field strength are derived from oscillations observed in coronal loops. We present a three-dimensional coronal simulation including a realistic energy balance in which we observe oscillations of a loop in synthesised coronal emission. We use these results to test the inversions based on coronal seismology. From the simulation of the corona above an active region we synthesise extreme ultraviolet (EUV) emission from the model corona. From this we derive maps of line intensity and Doppler shift providing synthetic data in the same format as obtained from observations. We fit the (Doppler) oscillation of the loop in the same fashion as done for observations to derive the oscillation period and damping time. The loop oscillation seen in our model is similar to imaging and spectroscopic observations of the Sun. The velocity disturbance of the kink oscillation shows an oscillation period of 52.5s and a damping tim...

  11. Standing sausage modes in curved coronal slabs

    Science.gov (United States)

    Pascoe, D. J.; Nakariakov, V. M.

    2016-09-01

    Context. Magnetohydrodynamic waveguides such as dense coronal loops can support standing modes. The ratios of the periods of oscillations for different longitudinal harmonics depend on the dispersive nature of the waveguide and so may be used as a seismological tool to determine coronal parameters. Aims: We extend models of standing sausage modes in low β coronal loops to include the effects of loop curvature. The behaviour of standing sausage modes in this geometry is used to explain the properties of observed oscillations that cannot be accounted for using straight loop models. Methods: We perform 2D numerical simulations of an oscillating coronal loop, modelled as a dense slab embedded in a potential magnetic field. The loop is field-aligned and so experiences expansion with height in addition to being curved. Standing sausage modes are excited by compressive perturbations of the loop and their properties are studied. Results: The spatial profiles of standing sausage modes are found to be modified by the expanding loop geometry typical for flaring loops and modelled by a potential magnetic field in our simulations. Longitudinal harmonics of order n > 1 have anti-nodes that are shifted towards the loop apex and the amplitude of anti-nodes near the loop apex is smaller than those near the loop footpoints. Conclusions: We find that the observation of standing sausage modes by the Nobeyama Radioheliograph in a flaring coronal loop on 12 January 2000 is consistent with interpretation in terms of the global mode (n = 1) and third harmonic (n = 3). This interpretation accounts for the period ratio and spatial structure of the observed oscillations.

  12. A Two-Fluid, MHD Coronal Model

    Science.gov (United States)

    Suess, S. T.; Wang, A.-H.; Wu, S. T.; Poletto, G.; McComas, D. J.

    1999-01-01

    We describe first results from a numerical two-fluid MHD model of the global structure of the solar Corona. The model is two-fluid in the sense that it accounts for the collisional energy exchange between protons and electrons. As in our single-fluid model, volumetric heat and Momentum sources are required to produce high speed wind from Corona] holes, low speed wind above streamers, and mass fluxes similar to the empirical solar wind. By specifying different proton and electron heating functions we obtain a high proton temperature in the coronal hole and a relatively low proton temperature above the streamer (in comparison with the electron temperature). This is consistent with inferences from SOHO/UltraViolet Coronagraph Spectrometer instrument (UVCS), and with the Ulysses/Solar Wind Observations Over the Poles of the Sun instrument (SWOOPS) proton and electron temperature measurements which we show from the fast latitude scan. The density in the coronal hole between 2 and 5 solar radii (2 and 5 R(sub S)) is similar to the density reported from SPARTAN 201.-01 measurements by Fisher and Guhathakurta [19941. The proton mass flux scaled to 1 AU is 2.4 x 10(exp 8)/sq cm s, which is consistent with Ulysses observations. Inside the closed field region, the density is sufficiently high so that the simulation gives equal proton and electron temperatures due to the high collision rate. In open field regions (in the coronal hole and above the streamer) the proton and electron temperatures differ by varying amounts. In the streamer the temperature and density are similar to those reported empirically by Li et al. [1998], and the plasma beta is larger than unity everywhere above approx. 1.5 R(sub S), as it is in all other MHD coronal streamer models [e.g., Steinolfson et al., 1982; also G. A. Gary and D. Alexander, Constructing the coronal magnetic field, submitted to Solar Physics, 1998].

  13. Nonlinear Force-free Coronal Magnetic Stereoscopy

    Science.gov (United States)

    Chifu, Iulia; Wiegelmann, Thomas; Inhester, Bernd

    2017-03-01

    Insights into the 3D structure of the solar coronal magnetic field have been obtained in the past by two completely different approaches. The first approach are nonlinear force-free field (NLFFF) extrapolations, which use photospheric vector magnetograms as boundary condition. The second approach uses stereoscopy of coronal magnetic loops observed in EUV coronal images from different vantage points. Both approaches have their strengths and weaknesses. Extrapolation methods are sensitive to noise and inconsistencies in the boundary data, and the accuracy of stereoscopy is affected by the ability of identifying the same structure in different images and by the separation angle between the view directions. As a consequence, for the same observational data, the 3D coronal magnetic fields computed with the two methods do not necessarily coincide. In an earlier work (Paper I) we extended our NLFFF optimization code by including stereoscopic constrains. The method was successfully tested with synthetic data, and within this work, we apply the newly developed code to a combined data set from SDO/HMI, SDO/AIA, and the two STEREO spacecraft. The extended method (called S-NLFFF) contains an additional term that monitors and minimizes the angle between the local magnetic field direction and the orientation of the 3D coronal loops reconstructed by stereoscopy. We find that when we prescribe the shape of the 3D stereoscopically reconstructed loops, the S-NLFFF method leads to a much better agreement between the modeled field and the stereoscopically reconstructed loops. We also find an appreciable decrease by a factor of two in the angle between the current and the magnetic field. This indicates the improved quality of the force-free solution obtained by S-NLFFF.

  14. Estudio prospectivo randomizado comparando apendicectomía laparoscópica versus apendicectomía mediante incisión umbilical única

    OpenAIRE

    Abrisqueta Carrión, Jesús

    2012-01-01

    El uso del SILS puede suponer una mejora con respecto a la cirugía laparoscópica convencional en la apendicectomia. Cada vez más artículos son publicados poniendo de manifiesto la viabilidad de este abordaje, por lo que esta tesis doctoral presenta un estudio prospectivo randomizado comparando ambas técnicas. Entre Septiembre de 2009 a Diciembre de 2010, 184 pacientes con diagnóstico e indicación quirúrgica de apendicitis aguda fueron incluidos en el estudio, 91 se les realizó apendicectom...

  15. Catéter central de acceso periférico en paciente pediátrico con cáncer: estudio de caso

    OpenAIRE

    Rocío López Rangel; Marcela Cárdenas Fandiño

    2015-01-01

    Introducción: Explorar el empleo del catéter central de acceso periférico para uso mixto (intrahospitalario-ambulatorio) y su efecto sobre la adherencia y el bienestar en el paciente pediátrico con cáncer tratado con quimioterapia en el INC cuando es candidato para inserción de catéter implantable. Materiales y Métodos: Estudio de abordaje cualitativo de tipo estudio de caso.  Se realizó inserción intrahospitalaria de catéter central de acceso periférico por enfermera. Para el alta del pacien...

  16. Estudio diferencial del nivel de estrés percibido, liderazgo, cohesión y autoconfianza en Unidades de Élite de la Armada Española, en la Operación Active Endeavour de la OTAN

    OpenAIRE

    Ángel J. Galindo

    2014-01-01

    Antecedentes y objetivos: Fruto de los atentados terroristas del 11 de septiembre de 2001 en Estados Unidos, surge la operación antiterrorista Active Endeavour con la participación de la Armada Española con la función de control marítimo y el abordaje de buques con actividad sospechosa terrorista. Este estudio trata de analizar las características diferenciales de los grupos especiales de abordaje de buques (boarding teams), en relación a sus niveles de estrés percibido, liderazgo, cohesión y...

  17. Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

    Indian Academy of Sciences (India)

    Milan Minarovjech; Milan Rybansky; Vojtech Rusin

    2000-09-01

    We present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of whitelight coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

  18. The Coronal Global Evolutionary Model (CGEM)

    Science.gov (United States)

    Fisher, George H.; DeRosa, M. L.; Hoeksema, J. T.

    2013-07-01

    The Coronal Global Evolutionary Model, or CGEM, is a collaborative effort from the UC Berkeley Space Sciences Laboratory (SSL), Stanford University, and Lockheed-Martin. In work that led up to the selection of this project, the team demonstrated its capability to use sequences of vector magnetograms and Dopplergrams from the Helioseismic and Magnetic Imager (HMI) instrument aboard the SDO to drive a magnetofrictional (MF) model of the coronal magnetic field in AR 11158, which produced an X2.2 flare. We will implement this MF model in spherical coordinates to enable real-time, long-term modeling of the non-potential coronal magnetic field, both globally and for individual active region (ARs). The model's Earth-facing hemisphere will be driven using electric fields derived from the observed evolution of photospheric line-of-sight magnetic fields and electric currents. Far-side data inputs will be from an existing flux transport code, combined with HMI far-side observations of new active regions, with empirical parametrizations of orientation and flux. Because this model includes large-scale coronal electric currents, it is a substantial improvement over existing real-time global coronal models, which assume potential fields. Data products available from the model will include: 1) the evolving photospheric electric field, Poynting flux, and helicity flux; 2) estimates of coronal free energy and non-potential geometry and topology; 3) initial and time-dependent boundary conditions for MHD modeling of active regions; and 4) time-dependent boundary conditions and flux tube expansion factors for MHD and empirical solar wind models. Unstable configurations found from MF models will be dynamically evolved with local and global MHD codes. Modules used to derive surface electric fields from magnetic evolution will be incorporated into the SDO/HMI data pipeline, and data products will be distributed through the Joint Science Operations Center (JSOC) and directly to space

  19. Reconnection and Spire Drift in Coronal Jets

    Science.gov (United States)

    Moore, Ronald; Sterling, Alphonse; Falconer, David

    2015-04-01

    It is observed that there are two morphologically-different kinds of X-ray/EUV jets in coronal holes: standard jets and blowout jets. In both kinds: (1) in the base of the jet there is closed magnetic field that has one foot in flux of polarity opposite that of the ambient open field of the coronal hole, and (2) in coronal X-ray/EUV images of the jet there is typically a bright nodule at the edge of the base. In the conventional scenario for jets of either kind, the bright nodule is a compact flare arcade, the downward product of interchange reconnection of closed field in the base with impacted ambient open field, and the upper product of this reconnection is the jet-outflow spire. It is also observed that in most jets of either kind the spire drifts sideways away from the bright nodule. We present the observed bright nodule and spire drift in an example standard jet and in two example blowout jets. With cartoons of the magnetic field and its reconnection in jets, we point out: (1) if the bright nodule is a compact flare arcade made by interchange reconnection, then the spire should drift toward the bright nodule, and (2) if the bright nodule is instead a compact flare arcade made, as in a filament-eruption flare, by internal reconnection of the legs of the erupting sheared-field core of a lobe of the closed field in the base, then the spire, made by the interchange reconnection that is driven on the outside of that lobe by the lobe’s internal convulsion, should drift away from the bright nodule. Therefore, from the observation that the spire usually drifts away from the bright nodule, we infer: (1) in X-ray/EUV jets of either kind in coronal holes the interchange reconnection that generates the jet-outflow spire usually does not make the bright nodule; instead, the bright nodule is made by reconnection inside erupting closed field in the base, as in a filament eruption, the eruption being either a confined eruption for a standard jet or a blowout eruption (as

  20. Cuantificadores como evidencia del lenguaje de la incertidumbre: un abordaje psicolingüístico

    Directory of Open Access Journals (Sweden)

    Jorge Luis Bazán Guzmán

    2006-12-01

    Full Text Available Se presenta una aproximación teórica para estudiar los cuantificadores como evidencia del lenguaje de incertidumbre. Se consideran los siguientes temas: lenguaje e incertidumbre, razonamiento probabilístico, aprendizaje y evaluación de los cuantificadores, y estudio de los cuantificadores como estudio del significado y la comprensión de palabras, los cuales constituyen la psicolingüística de los cuantificadores. Nosotros argumentamos que los cuantificadores, como palabras, forman parte del lenguaje de incertidumbre que es parte del razonamiento probabilístico, pero el mecanismo de su aprendizaje es desconocido. También consideramos que es importante situar el estudio de los cuantificadores dentro del estudio del significado como evidencia de procesos psicológicos internos. Investigaciones futuras ayudarán a una mayor comprensión del uso de los cuantificadores.

  1. GANGLIO CENTINELA EN MELANOMA DE CARA: ABORDAJE INICIAL Sentinel ganglion in melanoma of the face: an initial approach

    Directory of Open Access Journals (Sweden)

    Enrique Cadena-Piñeros

    2012-09-01

    Full Text Available A pesar de las campañas preventivas no se ha logrado disminuir la incidencia de las neoplasias cutáneas, probablemente por las alteraciones de la capa de ozono, con el consecuente aumento de la radiación ultravioleta, por eso en países del trópico se presentan lesiones como el melanoma de piel, que es considerado como una de las lesiones tumorales más agresivas. La cara y el cuello son zonas del cuerpo con una alta exposición solar, reflejándose en un mayor número de casos de este sombrío tumor. El mayor factor pronóstico en contra de los pacientes que padecen esta enfermedad es la presencia de metástasis ganglionares, por eso el grupo tratante debe esclarecer si están presentes, debido a esto hace varias décadas se realizan disecciones de cuello profilácticas, pero en la mayoría de los casos los ganglios extirpados son negativos. Una posible solución para evitar esto, es la extracción del o de los primeros ganglios que drenan el sitio del tumor primario (Ganglio Centinela. En el área de cabeza y cuello usualmente están presentes varios a la vez, lo que dificulta tomar la decisión de cuál extirpar. En nuestro grupo hemos iniciado la estandarización de esta técnica, y como abordaje inicial se realizó el primer caso de una paciente con melanoma de la cara a quien se practicó resección local amplia del tumor y extracción de los centinelas marcados por linfogammagrafía y a la vez disección de los relevos ganglionares positivos para drenaje demostrados por este estudio de medicina nuclear.In spite of preventative campaigns having been mounted, it still has not been possible to reduce cutaneous neoplasia incidence, probably due to alterations in the ozone layer. This has led to a consequent increase in ultraviolet radiation and thus lesions occurring in tropical countries such as skin cancer (melanoma, considered as being one of the most aggressive tumour lesions. The face and neck are the body areas having the highest

  2. Solar coronal observations at high frequencies

    CERN Document Server

    Katsiyannis, A C; Phillips, K J H; Williams, D R; Keenan, F P

    2001-01-01

    The Solar Eclipse Coronal Imaging System (SECIS) is a simple and extremely fast, high-resolution imaging instrument designed for studies of the solar corona. Light from the corona (during, for example, a total solar eclipse) is reflected off a heliostat and passes via a Schmidt-Cassegrain telescope and beam splitter to two CCD cameras capable of imaging at 60 frames a second. The cameras are attached via SCSI connections to a purpose-built PC that acts as the data acquisition and storage system. Each optical channel has a different filter allowing observations of the same events in both white light and in the green line (Fe XIV at 5303 A). Wavelet analysis of the stabilized images has revealed high frequency oscillations which may make a significant contribution on the coronal heating process. In this presentation we give an outline of the instrument and its future development.

  3. Selamento coronário em Endodontia

    OpenAIRE

    Oliveira, Rui Pedro Barra de Sá

    2016-01-01

    Introdução: A Endodontia é a especialidade da Medicina Dentária responsável pelo estudo e tratamento da câmara pulpar, de todo o sistema de canais radiculares e dos tecidos periapicais, bem como das doenças que os afetam. O selamento da porção coronária dos dentes alvo de tratamento endodôntico apresenta-se como um critério determinante no sucesso ou insucesso do tratamento. São vários os fatores que podem proporcionar um correto selamento coronário evitando assim a microinfiltração de ...

  4. Magnetic Topology of Coronal Hole Linkages

    CERN Document Server

    Titov, V S; Linker, J A; Lionello, R; Antiochos, S K

    2010-01-01

    In recent work, Antiochos and coworkers argued that the boundary between the open and closed field regions on the Sun can be extremely complex with narrow corridors of open flux connecting seemingly disconnected coronal holes from the main polar holes, and that these corridors may be the sources of the slow solar wind. We examine, in detail, the topology of such magnetic configurations using an analytical source surface model that allows for analysis of the field with arbitrary resolution. Our analysis reveals three important new results: First, a coronal hole boundary can join stably to the separatrix boundary of a parasitic polarity region. Second, a single parasitic polarity region can produce multiple null points in the corona and, more important, separator lines connecting these points. It is known that such topologies are extremely favorable for magnetic reconnection, because they allow this process to occur over the entire length of the separators rather than being confined to a small region around the...

  5. Damped transverse oscillations of interacting coronal loops

    CERN Document Server

    Soler, Roberto

    2015-01-01

    Damped transverse oscillations of magnetic loops are routinely observed in the solar corona. This phenomenon is interpreted as standing kink magnetohydrodynamic waves, which are damped by resonant absorption owing to plasma inhomogeneity across the magnetic field. The periods and damping times of these oscillations can be used to probe the physical conditions of the coronal medium. Some observations suggest that interaction between neighboring oscillating loops in an active region may be important and can modify the properties of the oscillations compared to those of an isolated loop. Here we theoretically investigate resonantly damped transverse oscillations of interacting non-uniform coronal loops. We provide a semi-analytic method, based on the T-matrix theory of scattering, to compute the frequencies and damping rates of collective oscillations of an arbitrary configuration of parallel cylindrical loops. The effect of resonant damping is included in the T-matrix scheme in the thin boundary approximation. ...

  6. Solar Coronal Jets: Observations, Theory, and Modeling

    CERN Document Server

    Raouafi, N E; Pariat, E; Young, P R; Sterling, A C; Savcheva, A; Shimojo, M; Moreno-Insertis, F; DeVore, C R; Archontis, V; Török, T; Mason, H; Curdt, W; Meyer, K; Dalmasse, K; Matsui, Y

    2016-01-01

    Coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of significant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of "nominal" solar flares and coronal mass ejections (CMEs), jets share many common properties with these phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients close or at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broad range of solar-heliospheric problems.

  7. Chemical Fractionation and Abundances in Coronal Plasma

    CERN Document Server

    Drake, J J

    2003-01-01

    Much of modern astrophysics is grounded on the observed chemical compositions of stars and the diffuse plasma that pervades the space between stars, galaxies and clusters of galaxies. X-ray and EUV spectra of the hot plasma in the outer atmospheres of stars have demonstrated that these environments are subject to chemical fractionation in which the abundances of elements can be enhanced and depleted by an order of magnitude or more. These coronal abundance anomalies are discussed and some of the physical mechanisms that might be responsible for producing them are examined. It is argued that coronal abundances can provide important new diagnostics on physical processes at work in solar and stellar coronae. It seems likely that other hot astrophysical plasmas will be subject to similar effects.

  8. Microflares as Possible Sources for Coronal Heating

    Indian Academy of Sciences (India)

    Meera Gupta; Rajmal Jain; Jayshree Trivedi; A. P. Mishra

    2008-03-01

    We present a preliminary study of 27 microflares observed by Solar X-ray Spectrometer (SOXS) mission during July 2003 to August 2006. We found that all 27 microflares show the Fe-line feature peaking around 6.7 keV, which is an indicator of the presence of coronal plasma temperature ≥ 9 MK. On the other hand, the spectra of microflares showhybrid model of thermal and non-thermal emission, which further supports them as possible sources of coronal heating. Our results based on the analysis show that the energy relapsed by the microflares is good enough for heating of the active corona. We discuss our results in the light of the hybrid model of microflares production.

  9. Adulto mayor: propuesta de abordaje de la neumonía adquirida en la comunidad

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Serra Valdés

    2016-04-01

    Full Text Available Fundamento: la neumonía adquirida en la comunidad constituye la causa principal de hospitalización entre los ancianos. Su letalidad es elevada. En la actualidad existen diversos scores de riesgo y pronóstico, así como diferentes Guías Prácticas Clínicas.Objetivo: elaborar una propuesta para el abordaje de la neumonía adquirida en la comunidad en el anciano, aplicable tanto en la Atención Primaria de Salud, como en la hospitalización.Métodos: se realizó la búsqueda de información mediante términos de indexación sobre neumonía adquirida en la comunidad, en especial en el adulto mayor o anciano, así como guías existentes nacionales y de diferentes países, sociedades y consensos regionales a través de Clinical Evidence, The Cochrane Library, PUBMED, Google Académico, MEDLINE, LIS, Scielo, Medscape, LILACS, Latindex, HINARI, MEDIGRAPHIC-NEWS y otros. Se asumieron aquellas publicaciones que reunían las evidencias de mayor calidad de acuerdo con los criterios de Grading of Recommendations of Assessment Development and Evaluations. Resultados: se elaboró una propuesta de abordaje práctico en cualquier nivel de atención de nuestro sistema de salud y teniendo en cuenta el cuadro básico de medicamentos actual. Se consideró la epidemiología, factores de riesgo, estratificación del riesgo, tratamiento y letalidad. Conclusiones: la neumonía adquirida en la comunidad constituye un problema actual y un reto futuro. Esta propuesta puede ser utilizada por los profesionales que participan en la asistencia de esta afección en cualquier nivel de atención. Su aplicación pudiera mejorar la atención médica, disminuir la letalidad, los costos y mejorar la calidad de vida.

  10. Bridging the Gap between Coronal and Non-Coronal Evolved Stars

    Science.gov (United States)

    Carpenter, Kenneth G.; Nielsen, Krister E.; Kober, Gladys V.

    2017-01-01

    The Hubble Space Telescope (HST) Treasury Program "Advanced Spectral Library (ASTRAL)" enables investigations of a broad range of problems including the character and dynamics of the wind and chromosphere of cool stars. This paper presents an investigation of the change in spectral characteristics when transitioning from the cool non-coronal objects with fluorescent emission spectra from the iron group elements, molecular hydrogen, and carbon monoxide to the warmer stars on the blue side of the Linsky-Haish dividing line in the HR diagram. These warmer objects exhibit chromospheric emission from significantly hotter environments in addition to coronal signatures, while the hybrid stars overlap in the HR-diagram with some of the non-coronal objects and share many spectral characteristics but show differences in the wind properties. We show how the wind, fluorescent features, and hot stellar signatures dramatically change with spectral class by comparing the already analyzed non-coronal objects (Alpha Ori, Gamma Cru) with the hybrid stars (Gamma Dra, Beta Gem and Alpha Aqr) and the coronal object Beta Dra. We aim to gain understanding of the physical processes in these objects' outer atmospheres and their evolutionary tracks.

  11. Relationship of EUV Irradiance Coronal Dimming Slope and Depth to Coronal Mass Ejection Speed and Mass

    CERN Document Server

    Mason, James Paul; Webb, David F; Thompson, Barbara J; Colaninno, Robin C; Vourlidas, Angelos

    2016-01-01

    Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary void left behind by a coronal mass ejection (CME). Massive, fast CMEs tend to leave behind a darker void that also usually corresponds to minimum irradiance for the cooler coronal emissions. If the dimming is associated with a solar flare, as is often the case, the flare component of the irradiance light curve in the cooler coronal emission can be isolated and removed using simultaneous measurements of warmer coronal lines. We apply this technique to 37 dimming events identified during two separate two-week periods in 2011, plus an event on 2010 August 7 analyzed in a previous paper, to parameterize dimming in terms of depth and slope. We provide statistics on which combination of wavelengths worked best for the flare-removal method, describe the fitting methods applied to t...

  12. Tipología de propuestas de abordaje de contenidos de Lengua y Literatura con inclusión de TIC

    Directory of Open Access Journals (Sweden)

    Alejo Ezequiel González López Ledesma

    2014-10-01

    Full Text Available En un estudio previo (Álvarez y González, en prensa, recurrimos a los principios básicos de la teoría fundamentada para analizar las modalidades de inclusión de las tecnologías de la información y la comunicación (TIC en propuestas didácticas de abordaje de contenidos de Lengua y Literatura. Caracterizamos las propuestas analizadas en función de diferentes categorías: contenido disciplinar, destinatarios, propuesta de trabajo, enfoque disciplinar del contenido, recursos tecnológicos y tipos de inclusión tecnológica. En el trabajo que presentamos ahora, partimos de esa categorización con el objeto de verificarla, ampliarla y ajustarla a partir de un corpus de propuestas más amplio. Para ello, hemos optado por articular las dimensiones didáctica, tecnológica y disciplinar. De esta manera, establecimos una tipología –por el momento provisoria– que da cuenta de las diferentes modalidades de inclusión de las TIC en propuestas que abordan contenidos propios del área de Lengua y Literatura: inclusión de tecnología como soporte del desarrollo de contenidos y actividades; inclusión de tecnología para ejemplificar su uso a partir de un contenido; e inclusión de tecnología para crear e innovar.

  13. Coronal Mass Ejections of Solar Cycle 23

    Indian Academy of Sciences (India)

    Nat Gopalswamy

    2006-06-01

    I summarize the statistical, physical, and morphological properties of coronal mass ejections (CMEs) of solar cycle 23, as observed by the Solar and Heliospheric Observatory (SOHO) mission. The SOHO data is by far the most extensive data, which made it possible to fully establish the properties of CMEs as a phenomenon of utmost importance to Sun–Earth connection as well as to the heliosphere. I also discuss various subsets of CMEs that are of primary importance for their impact on Earth.

  14. Coronal Plumes in the Fast Solar Wind

    Science.gov (United States)

    Velli, Marco; Lionello, Roberto; Linker, Jon A.; Mikic, Zoran

    2011-01-01

    The expansion of a coronal hole filled with a discrete number of higher density coronal plumes is simulated using a time-dependent two-dimensional code. A solar wind model including an exponential coronal heating function and a flux of Alfven waves propagating both inside and outside the structures is taken as a basic state. Different plasma plume profiles are obtained by using different scale heights for the heating rates. Remote sensing and solar wind in situ observations are used to constrain the parameter range of the study. Time dependence due to plume ignition and disappearance is also discussed. Velocity differences of the order of approximately 50 km/s, such as those found in microstreams in the high-speed solar wind, may be easily explained by slightly different heat deposition profiles in different plumes. Statistical pressure balance in the fast wind data may be masked by the large variety of body and surface waves which the higher density filaments may carry, so the absence of pressure balance in the microstreams should not rule out their interpretation as the extension of coronal plumes into interplanetary space. Mixing of plume-interplume material via the Kelvin-Helmholtz instability seems to be possible within the parameter ranges of the models defined here, only at large di stances from the Sun, beyond 0.2-0.3 AU. Plasma and composition measurements in the inner heliosphere, such as those which will become available with Solar Orbiter and Solar Probe Plus, should therefore definitely be able to identify plume remnants in the solar wind.

  15. Interchange Reconnection and Coronal Hole Dynamics

    Science.gov (United States)

    2010-05-01

    calculate the time-dependent dynamics of coronal hole boundaries rigorously and test our conjectures. We describe below our numerical simulations of...radiation and thermal conduction are needed in order to test such a model. It is tempting to conjecture that this process of releasing the closed-field... HTP , TR&T, and SR&T Programs, and has benefited greatly from the authors’ participation in the NASA TR&T focused science team on the solar

  16. Coronal Structure of Low-Mass Stars

    CERN Document Server

    Lang, Pauline; Donati, Jean-Francois; Morin, Julien; Vidotto, Aline

    2012-01-01

    We investigate the change in stellar magnetic topology across the fully-convective boundary and its effects on coronal properties. We consider both the magnitude of the open flux that influences angular momentum loss in the stellar wind and X-ray emission measure. We use reconstructed maps of the radial magnetic field at the stellar surface and the potential-field source surface method to extrapolate a 3D coronal magnetic field for a sample of early-to-mid M dwarfs. During the magnetic reconstruction process it is possible to force a solution towards field geometries that are symmetric or antisymmetric about the equator but we demonstrate that this has only a modest impact on the coronal tracers mentioned above. We find that the dipole component of the field, which governs the large-scale structure, becomes increasingly strong as the stellar mass decreases, while the magnitude of the open (wind-bearing) magnetic flux is proportional to the magnitude of the reconstructed magnetic flux. By assuming a hydrostati...

  17. A Mechanism for Coronal Hole Jets

    CERN Document Server

    Mueller, D A N

    2008-01-01

    Bald patches are magnetic topologies in which the magnetic field is concave up over part of a photospheric polarity inversion line. A bald patch topology is believed to be the essential ingredient for filament channels and is often found in extrapolations of the observed photospheric field. Using an analytic source-surface model to calculate the magnetic topology of a small bipolar region embedded in a global magnetic dipole field, we demonstrate that although common in closed-field regions close to the solar equator, bald patches are unlikely to occur in the open-field topology of a coronal hole. Our results give rise to the following question: What happens to a bald patch topology when the surrounding field lines open up? This would be the case when a bald patch moves into a coronal hole, or when a coronal hole forms in an area that encompasses a bald patch. Our magnetostatic models show that, in this case, the bald patch topology almost invariably transforms into a null point topology with a spine and a fa...

  18. The formation of an equatorial coronal hole

    Science.gov (United States)

    Yang, Liheng; Jiang, Yunchun; Zhang, Jun

    2010-02-01

    The formation of an equatorial coronal hole (CH) from 2006 January 9 to 12 was simultaneously observed by GOES-12/SXI, SOHO/EIT and SOHO/MDI instruments. The varieties of soft X-ray and EUV brightness, coronal temperature, and total magnetic flux in the CH were examined and compared with that of a quiet-sun (QS) region nearby. The following results are obtained. (1) A preexisting dark lane appeared on the location of the followed CH and was reinforced by three enhanced networks. (2) The CH gradually formed in about 81 hours and was predominated by positive magnetic flux. (3) During the formation, the soft X-ray and EUV brightness, coronal temperature, and total magnetic flux obviously decreased in the CH, but were almost no change in the QS region. The decrease of the total magnetic flux may be the result of magnetic reconnection between the open and closed magnetic lines, probably indicating the physical mechanism for the birth of the CH.

  19. Propagating magnetohydrodynamics waves in coronal loops.

    Science.gov (United States)

    De Moortel, I

    2006-02-15

    High cadence Transition Region and Coronal Explorer (TRACE) observations show that outward propagating intensity disturbances are a common feature in large, quiescent coronal loops, close to active regions. An overview is given of measured parameters of such longitudinal oscillations in coronal loops. The observed oscillations are interpreted as propagating slow magnetoacoustic waves and are unlikely to be flare-driven. A strong correlation, between the loop position and the periodicity of the oscillations, provides evidence that the underlying oscillations can propagate through the transition region and into the corona. Both a one- and a two-dimensional theoretical model of slow magnetoacoustic waves are presented to explain the very short observed damping lengths. The results of these numerical simulations are compared with the TRACE observations and show that a combination of the area divergence and thermal conduction agrees well with the observed amplitude decay. Additionally, the usefulness of wavelet analysis is discussed, showing that care has to be taken when interpreting the results of wavelet analysis, and a good knowledge of all possible factors that might influence or distort the results is a necessity.

  20. Coronal Heating Observed with Hi-C

    Science.gov (United States)

    Winebarger, Amy R.

    2013-01-01

    The recent launch of the High-Resolution Coronal Imager (Hi-C) as a sounding rocket has offered a new, different view of the Sun. With approx 0.3" resolution and 5 second cadence, Hi-C reveals dynamic, small-scale structure within a complicated active region, including coronal braiding, reconnection regions, Alfven waves, and flows along active region fans. By combining the Hi-C data with other available data, we have compiled a rich data set that can be used to address many outstanding questions in solar physics. Though the Hi-C rocket flight was short (only 5 minutes), the added insight of the small-scale structure gained from the Hi-C data allows us to look at this active region and other active regions with new understanding. In this talk, I will review the first results from the Hi-C sounding rocket and discuss the impact of these results on the coronal heating problem.

  1. Dynamics of Coronal-Hole Boundaries

    CERN Document Server

    Higginson, A K; DeVore, C R; Wyper, P F; Zurbuchen, T H

    2016-01-01

    Remote and in-situ observations suggest that the slow solar wind consists of plasma from the hot, closed-field corona that is released onto open magnetic field lines. The Separatrix-Web (S-Web) theory for the slow wind proposes that photospheric motions, at the scale of supergranules, are responsible for generating dynamics at coronal-hole boundaries, which result in the inferred necessary transfer of plasma from closed to open field lines. We use 3D magnetohydrodynamic (MHD) simulations to determine the effect of photospheric flows on the open and closed magnetic flux of a model corona with a dipole magnetic field and an isothermal solar wind. We find that a supergranular-scale photospheric motion at the boundary between the coronal hole and helmet streamer results in prolific and efficient interchange reconnection between open and closed flux. This reconnection acts to smooth the large- and small-scale structure introduced by the photospheric flows. Magnetic flux near the coronal-hole boundary experiences m...

  2. The Lower Chromosphere in a Coronal Hole

    Science.gov (United States)

    Teplitskaya, R. B.; Turova, I. P.; Ozhogina, O. A.

    2007-07-01

    We study the Ca ii K, H, and λ 849.8 nm line profiles in two regions of the quiet Sun, one being located in the extensive low-latitude coronal hole observed on 3 through 5 August 2003, and the other being located outside the coronal hole. Comparison of the profiles was carried out separately for cells and cell boundaries of the chromospheric network. Our principal result is that space- and time-averaged profiles of the central self-reversal in the coronal hole sites differ from those outside of the hole: Intensities of the K3 and H3 central depressions are increased in the cells but are unchanged in the network; the height of the K2 peaks is reduced in the cells and particularly in the network; the central self-reversal asymmetry is intensified in the network. Distinctions appear at a high confidence level. Line wings as well as average characteristics of the infrared line remain practically unchanged. We discuss probable causes for this behavior of the lower chromosphere lines.

  3. Characteristics of polar coronal hole jets

    CERN Document Server

    Chandrashekhar, K; Banerjee, D; Gupta, G R; Teriaca, L

    2013-01-01

    High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. We found observational evidence that supports the idea that polar jets are very likely produced by multiple small-scale reconnections occurring at different times in different locations. These eject plasma blobs that flow up and down with a motion very similar to a simple ballistic motion. The associated drift speed of the first jet is estimated to be $\\approx$ 27 km s$^{-1}$. The average outward speed of the first jet is $\\approx 171$ km s$^{-1}$, well below the escape speed, hence if simple ballistic motio...

  4. The acceleration of electrons at a spherical coronal shock in a streamer-like coronal field

    Science.gov (United States)

    Kong, Xiangliang; Chen, Yao; Guo, Fan

    2016-03-01

    We study the effect of large-scale coronal magnetic field on the electron acceleration at a spherical coronal shock using a test-particle method. The coronal field is approximated by an analytical solution with a streamer-like magnetic field featured by partially open magnetic field and a current sheet at the equator atop the closed region. It shows that the closed field plays the role of a trapping agency of shock-accelerated electrons, allowing for repetitive reflection and acceleration, therefore can greatly enhance the shock-electron acceleration efficiency. It is found that, with an ad hoc pitch-angle scattering, electron injected in the open field at the shock flank can be accelerated to high energies as well. In addition, if the shock is faster or stronger, a relatively harder electron energy spectrum and a larger maximum energy can be achieved.

  5. Standing Slow-Mode Waves in Hot Coronal Loops: Observations, Modeling, and Coronal Seismology

    CERN Document Server

    Wang, Tongjiang

    2010-01-01

    Strongly damped Doppler shift oscillations are observed frequently associated with flarelike events in hot coronal loops. In this paper, a review of the observed properties and the theoretical modeling is presented. Statistical measurements of physical parameters (period, decay time, and amplitude) have been obtained based on a large number of events observed by SOHO/SUMER and Yohkoh/BCS. Several pieces of evidence are found to support their interpretation in terms of the fundamental standing longitudinal slow mode. The high excitation rate of these oscillations in small- or micro-flares suggest that the slow mode waves are a natural response of the coronal plasma to impulsive heating in closed magnetic structure. The strong damping and the rapid excitation of the observed waves are two major aspects of the waves that are poorly understood, and are the main subject of theoretical modeling. The slow waves are found mainly damped by thermal conduction and viscosity in hot coronal loops. The mode coupling seems ...

  6. A unified theory of electrodynamic coupling in coronal magnetic loops - The coronal heating problem

    Science.gov (United States)

    Ionson, J. A.

    1984-01-01

    The coronal heating problem is studied, and it is demonstrated that Ionson's (1982) LRC approach results in a unified theory of coronal heating which unveils a variety of new heating mechanisms and which links together previously proposed mechanisms. Ionson's LRC equation is rederived, focusing on various aspects that were not clarified in the original article and incorporating new processes that were neglected. A parameterized heating rate is obtained. It is shown that Alfvenic surface wave heating, stochastic magnetic pumping, resonant electrodynamic heating, and dynamical dissipation emerge as special cases of a much more general formalism. This generalized theory is applied to solar coronal loops and it is found that active region and large scale loops are underdamped systems. Young active region loops and (possibly) bright points are found to be overdamped systems.

  7. Abordaje integral comunitario de los consumos problemáticos de drogas: construyendo un modelo

    Directory of Open Access Journals (Sweden)

    Ana Clara Camarotti

    2015-01-01

    Full Text Available Se presentan los lineamientos del modelo integral comunitario del abordaje del consumo problemático de drogas. Estos comprenden las dimensiones de integralidad, vulnerabilidad y cuidados en sentido amplio. La caracterización de estas dimensiones lleva a lo que las autoras denominan modelo integral comunitario, en oposición al denominado modelo moralista normativo. Las diferencias entre ambos modelos se centran en las concepciones de salud, los objetivos de las actividades propuestas, las concepciones sobre los sujetos y los marcos operativos en los que se basan cada uno de ellos. Se proponen también los pasos que deberían seguirse en la aplicación del modelo comunitario, cuyo objetivo último es lograr un sistema de respuestas comunitarias para debilitar al sistema que genera el consumo problemático de drogas. Dichos pasos comprenden la identificación del problema por parte de la comunidad, la reunión de datos y experiencias previas, la organización comunitaria incluyendo la capacitación de sus agentes, el fortalecimiento y la articulación de los recursos existentes en la comunidad y el diseño consensuado de respuestas al problema.

  8. Crecer en movimiento. Abordaje etnográfico del desarrollo infantil en comunidades Mbya (Argentina

    Directory of Open Access Journals (Sweden)

    Carolina Remorini

    2010-10-01

    Full Text Available Me propongo analizar y discutir algunos resultados de una investigación etnográfica desarrollada en comunidades Mbya Guaraníes (Misiones, Argentina acerca de las representaciones y prácticas relacionadas con la crianza y el desarrollo infantil.En este trabajo caracterizo las categorías, representaciones y valores Mbya, en torno a los procesos de crecimiento y desarrollo, focalizando la mirada en el “movimiento” —en tanto indicador de “crecimiento” y salud—, en las prácticas cotidianas de crianza que lo promueven, y en las creencias y saberes que las justifican. A partir de ello, planteo la estrecha relación entre movimiento, salud e identidad.Discuto los resultados a la luz de conceptos y enfoques de la antropología, sociología y psicología, a fin de avanzar hacia la integración de diferentes aportes disciplinares en el abordaje del impacto del movimiento y otros modos de educación del cuerpo en el desarrollo infantil y sus variaciones según diversos contextos eco-culturales e históricos.

  9. Crecer en movimiento. Abordaje etnográfico del desarrollo infantil en comunidades Mbya (Argentina

    Directory of Open Access Journals (Sweden)

    Carolina Remorini

    2010-01-01

    Full Text Available Me propongo analizar y discutir algunos resultados de una investigación etnográfica desarrollada en comunidades Mbya Guaraníes (Misiones, Argentina acerca de las representaciones y prácticas relacionadas con la crianza y el desarrollo infantil. En este trabajo caracterizo las categorías, representaciones y valores Mbya, en torno a los procesos de crecimiento y desarrollo, focalizando la mirada en el "movimiento" -en tanto indicador de "crecimiento" y salud-, en las prácticas cotidianas de crianza que lo promueven, y en las creencias y saberes que las justifican. A partir de ello, planteo la estrecha relación entre movimiento, salud e identidad. Discuto los resultados a la luz de conceptos y enfoques de la antropología, sociología y psicología, a fin de avanzar hacia la integración de diferentes aportes disciplinares en el abordaje del impacto del movimiento y otros modos de educación del cuerpo en el desarrollo infantil y sus variaciones según diversos contextos ecoculturales e históricos.

  10. Comparativa de Abordajes de Cursos Introductorios de Programación

    Directory of Open Access Journals (Sweden)

    Mauricio R. Dávila

    2016-08-01

    Full Text Available El pensamiento computacional se basa en resolver problemas haciendo uso de conceptos de informática, desarrollar esta habilidad es la tarea principal de las asignaturas de introducción a la programación en las carreras universitarias. En general, aunque se han creado lenguajes cada vez más cercanos al lenguaje humano, la programación no resulta ser una materia intuitiva ni de fácil comprensión y, por lo tanto, suele tratarse de una asignatura con una alta tasa de deserción. En este contexto, se presenta una revisión de los métodos de enseñanza, el formato de ejercitación y el material utilizado en las materias iniciales de programación en la educación superior, tanto en universidades de los Estados Unidos como de la Argentina. A lo largo del trabajo se buscará determinar el estado de la cuestión, comparar los casos de las distintas universidades a fin de establecer qué aspectos de los distintos abordajes favorecen el proceso de la enseñanza y poder así realizar un esbozo de solución que apunte a disminuir los índices de deserción en las materias introductorias de programación.

  11. Realidad Virtual Acústica: El Abordaje de las Redes Neuronales Artificiales

    Directory of Open Access Journals (Sweden)

    Jose Francisco Lucio

    2015-05-01

    Full Text Available En este trabajo se presenta un nuevo abordaje para obtener las respuestas impulsivas biauriculares (BIRs para un sistema de aurilización utilizando un conjunto de redes neuronales artificiales (RNAs. El método propuesto es capaz de reconstruir las respuestas impulsivas asociadas a la cabeza humana (HRIRs por medio de modificación espectral y de interpolación espacial. Para poder cubrir todo el espacio auditivo de recepción, sin aumentar la complejidad de la arquitectura de la red, una estructura con varias RNAs (conjunto fue adoptada, donde cada red opera en una región específica del espacio (gomo. El error de modelaje en el dominio de la frecuencia es investigado considerando la naturaleza logarítmica de la audición humana. A través de la metodología propuesta se obtuvo un ahorro del tiempo de procesamiento computacional de aproximadamente 62% en relación al método tradicional de procesamiento de señales utilizado para aurilización. La aplicabilidad del nuevo método en sistemas de aurilización es reforzada mediante un análisis comparativo de los resultados, que incluyen la generación de las BIRs y el cálculo de un parámetro acústico biauricular (IACF, los cuales muestran errores con magnitudes reducidas.

  12. Segmentation of Coronal Holes Using Active Contours Without Edges

    CERN Document Server

    Boucheron, L E; McAteer, R T J

    2016-01-01

    An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. As the source of the fast solar wind, the detection and characterization of these regions is important for both testing theories of their formation and evolution and from a space weather perspective. Coronal holes are detected in full disk extreme ultraviolet (EUV) images of the corona obtained with the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). The proposed method detects coronal boundaries without determining any fixed intensity value in the data. Instead, the active contour segmentation employs an energy-minimization in which coronal holes are assumed to have more homogeneous intensities than surrounding active regions and quiet Sun. The segmented coronal holes tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind ...

  13. Estudio del horizonte local

    OpenAIRE

    Ros Ferré, Rosa Maria

    2009-01-01

    El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical).

  14. Reflexão sobre a abordagem etnográfica em três pesquisas Reflexión sobre el abordaje etnográfico en tres investigaciones Reflections on the ethnographic approach in three research studies

    Directory of Open Access Journals (Sweden)

    Neiva Francenely Cunha Vieira

    2003-10-01

    Full Text Available Este trabalho embasa-se em três pesquisas que focalizaram os efeitos da percepção nas atitudes dos adultos, com o objetivo de melhorar o cuidado de saúde da criança. Embora cada estudo pertença a uma área distinta de investigação, todos adotaram a abordagem etnográfica para analisar a interação entre adultos e crianças. Este estudo desenvolveu a reflexão dos pesquisadores com relação a: i adoção de uma abordagem etnográfica na produção científica de enfermagem; ii perspectivas teóricas relevantes na análise destes temas. Em suma, este estudo exemplifica o valor da reflexão sobre pesquisas já realizadas e seu potencial para aumentar o entendimento de como as pesquisas podem contribuir para consolidar os modelos de cuidado a saúde em geral e do cuidado de enfermagem, em particular.Este trabajo involucra tres estudios de investigación que se enfocaron en los efectos de la percepción en las actitudes de los adultos en los intentos por mejorar el cuidado de la salud del niño. Aunque cada estudio tenía un área distinta de investigación, todos adoptaron un abordaje etnográfico en la interacción entre adultos y niños. Este estudio muestra la reflexión de los autores en relación con: i adopción de un abordaje etnográfico en la producción científica de enfermería; ii perspectivas teóricas que demuestran ser relevantes en la producción de los temas. Se considera que el valor de esta reflexión post-investigación radica en su potencial para entender como este abordaje puede contribuir en la consolidación de un marco teórico relacionado con el cuidado de la salud en general y del cuidado de enfermería, em particular.This paper aims at analyzing three research studies that focused on the effects of the perception in adults´ attitudes with the purpose to improve the health care provided to children. Although each study had a distinct area of investigation, all of them adopted the ethnographic approach on the

  15. Solar jet-coronal hole collision and a related coronal mass ejection

    CERN Document Server

    Zheng, Ruisheng; Du, Guohui; Li, Chuanyang

    2016-01-01

    Jets are defined as impulsive, well-collimated upflows, occurring in different layers of the solar atmosphere with different scales. Their relationship with coronal mass ejections (CMEs), another type of solar impulsive events, remains elusive. Using the high-quality imaging data of AIA/SDO, here we show a well-observed coronal jet event, in which part of the jets, with the embedding coronal loops, runs into a nearby coronal hole (CH) and gets bounced towards the opposite direction. This is evidenced by the flat-shape of the jet front during its interaction with the CH and the V-shaped feature in the time-slice plot of the interaction region. About a half-hour later, a CME initially with a narrow and jet-like front is observed by the LASCO C2 coronagraph, propagating along the direction of the post-collision jet. We also observe some 304 A dark material flowing from the jet-CH interaction region towards the CME. We thus suggest that the jet and the CME are physically connected, with the jet-CH collision and t...

  16. SOLAR JET–CORONAL HOLE COLLISION AND A CLOSELY RELATED CORONAL MASS EJECTION

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Ruisheng; Chen, Yao; Du, Guohui; Li, Chuanyang, E-mail: ruishengzheng@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, 264209, Weihai (China)

    2016-03-10

    Jets are defined as impulsive, well-collimated upflows, occurring in different layers of the solar atmosphere with different scales. Their relationship with coronal mass ejections (CMEs), another type of solar impulsive events, remains elusive. Using high-quality imaging data from the Atmospheric Imaging Assembly/Solar Dynamics Observatory, we show a well-observed coronal jet event, in which the part of the jet with embedding coronal loops runs into a nearby coronal hole (CH) and gets bounced in the opposite direction. This is evidenced by the flat shape of the jet front during its interaction with the CH and the V-shaped feature in the time-slice plot of the interaction region. About a half-hour later, a CME with an initially narrow and jet-like front is observed by the LASCO C2 coronagraph propagating along the direction of the post-collision jet. We also observe some 304 Å dark material flowing from the jet–CH interaction region toward the CME. We thus suggest that the jet and the CME are physically connected, with the jet–CH collision and the large-scale magnetic topology of the CH being important in defining the eventual propagating direction of this particular jet–CME eruption.

  17. Solar coronal observations at high frequencies

    OpenAIRE

    Katsiyannis, A. C.; Mathioudakis, M.; Phillips, K. J. H.; Williams, D. R.; F. P. Keenan

    2001-01-01

    The Solar Eclipse Coronal Imaging System (SECIS) is a simple and extremely fast, high-resolution imaging instrument designed for studies of the solar corona. Light from the corona (during, for example, a total solar eclipse) is reflected off a heliostat and passes via a Schmidt-Cassegrain telescope and beam splitter to two CCD cameras capable of imaging at 60 frames a second. The cameras are attached via SCSI connections to a purpose-built PC that acts as the data acquisition and storage syst...

  18. Observing coronal nanoflares in active region moss

    OpenAIRE

    Testa, Paola; De Pontieu, Bart; Martinez-Sykora, Juan; DeLuca, Ed; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Golub, Leon; Kobayashi, Ken; Korreck, Kelly; Kuzin, Sergey; Walsh, Robert; DeForest, Craig; Title, Alan; Weber, Mark

    2013-01-01

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial (~0.3-0.4 arcsec) and temporal (5.5s) resolution. The Hi-C observations show in some moss regions variability on timescales down to ~15s, significantly shorter than the minute scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss r...

  19. Estrategia probesci: un abordaje terapéutico de menor coste para el paciente obeso Probesci strategy: a cheaper therapeutic approach for obese patients

    Directory of Open Access Journals (Sweden)

    C. Vázquez

    2006-12-01

    Full Text Available Desde la experiencia clínica todas las evidencias hacen suponer que la obesidad, epidemia que amenaza la Salud Pública de los países más ricos de la Tierra, se presenta como un síndrome que abarca distintas enfermedades, todas ellas con un rasgo común, el exceso de grasa corporal, pero con respuestas clínicas claramente diferenciadas ante la misma estrategia terapéutica. Si las respuestas son tan heterogéneas es que la etiopatogenia también lo es, por lo que un estudio fenotípico exhaustivo ayudaría a establecer grupos clínicos que presumiblemente tendrían una respuesta más homogénea ante el mismo tratamiento. En este caso el abordaje y manejo terapéutico de los distintos grupos clínicos permitiría diversificar el tratamiento y posiblemente, mejorar su efectividad. El gran inconveniente para llevar a la práctica un estudio fenotípico exhaustivo es el elevado coste, por el consumo de tiempos recursos humanos que exige, lo que es con frecuencia inviable. En este estudio se describe la "estrategia PROBESCI" como un sistema organizativo de estudio y recogida de datos que sistematiza, estandariza y caracteriza la información constituyendo la base para la consiguiente clasificación y establecimiento de perfiles fenotípicos dentro de la obesidad. Es una nueva modalidad de consulta inicial en grupo, de valoración del paciente obeso, que ha demostrado su viabilidad. Se estudian los costes de esta nueva modalidad, comparándolos con los de la consulta clásica y se demuestra que supone un gran ahorro, ya que disminuye un 58% los costes de la consulta inicial y un 21% los costes totales del tratamiento.Obesity has become epidemic in Western countries. From clinical practice, obestity may be considered as a disease characterized by an excess of body fat mass, but patients usually demonstrate different responses to the same therapeutic strategy. It could be possible that the latter may be a consecuence of different pathophysiological

  20. Abordaje del niño con hipercalcemia: reporte de 3 casos

    Directory of Open Access Journals (Sweden)

    Nancy Chavarría-Arana

    2013-09-01

    Full Text Available La hipercalcemia en niños es un trastorno electrolítico raro. Su presentación clínica es variable, al igual que su etiología. En esta publicación se abordan los casos de tres niños con hipercalcemia. Primeramente, un neonato de 24 días con irritabilidad, pobre succión y nefrocalcinosis. El segundo caso es de un niño de 1 año de edad con estenosis pulmonar, falla para progresar, retraso en el desarrollo psicomotor, fascies de duende y nefrocalcinosis. Por último, se presenta una niña de 11 años, con cuadro de dolor abdominal, polidipsia, náuseas, vómitos, lesiones líticas en huesos largos y anemia. Las causas determinadas para cada caso fueron, respectivamente: acidosis tubular distal, síndrome de Williams y leucemia linfocítica aguda. Para el abordaje del niño con hipercalcemia se muestran dos esquemas de diagnóstico realizados con fundamento en los hallazgos clínicos, laboratorio y gabinete. Laterapeúticaenestosniñosdebebasarseenelaumentode la excreción renal de calcio (hidratación, diuréticos, reducción de la absorción a nivel intestinal (restricción nutricional de calcio y vitamina D, glucocorticoides, inhibición de la resorción ósea (bifosfonatos, glucocorticoides, redistribución del calcio y, sobre todo, la prontitud con la que se instaure una terapia eficaz, ya que esta tendrá un impacto a largo plazo sobre su salud y calidad de vida.

  1. Relationship of EUV Irradiance Coronal Dimming Slope and Depth to Coronal Mass Ejection Speed and Mass

    Science.gov (United States)

    Mason, James Paul; Woods, Thomas N.; Webb, David F.; Thompson, Barbara J.; Colaninno, Robin C.; Vourlidas, Angelos

    2016-10-01

    Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary void left behind by a coronal mass ejection (CME). Massive, fast CMEs tend to leave behind a darker void that also usually corresponds to minimum irradiance for the cooler coronal emissions. If the dimming is associated with a solar flare, as is often the case, the flare component of the irradiance light curve in the cooler coronal emission can be isolated and removed using simultaneous measurements of warmer coronal lines. We apply this technique to 37 dimming events identified during two separate two-week periods in 2011 plus an event on 2010 August 7, analyzed in a previous paper to parameterize dimming in terms of depth and slope. We provide statistics on which combination of wavelengths worked best for the flare-removal method, describe the fitting methods applied to the dimming light curves, and compare the dimming parameters with corresponding CME parameters of mass and speed. The best linear relationships found are \\begin{eqnarray*}{v}{CME} ≤ft[\\displaystyle \\frac{{km}}{{{s}}}\\right] & ≈ & 2.36× {10}6 ≤ft[\\displaystyle \\frac{{km}}{ % }\\right]× {s}\\dim ≤ft[\\displaystyle \\frac{ % }{{{s}}}\\right]\\ {m}{CME} [{{g}}] & ≈ & 2.59× {10}15≤ft[\\displaystyle \\frac{g}{ % }\\right]× \\sqrt{{d}\\dim } [ % ].\\end{eqnarray*} These relationships could be used for space weather operations of estimating CME mass and speed using near-real-time irradiance dimming measurements.

  2. Evaluation of the Minifilament-Eruption Scenario for Solar Coronal Jets in Polar Coronal Holes

    Science.gov (United States)

    Baikie, Tomi K.; Sterling, Alphonse C.; Falconer, David; Moore, Ronald L.; Savage, Sabrina L.

    2016-01-01

    Solar coronal jets are suspected to result from magnetic reconnection low in the Sun's atmosphere. Sterling et al. (2015) looked as 20 jets in polar coronal holes, using X-ray images from the Hinode/X-Ray Telescope (XRT) and EUV images from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA). They suggested that each jet was driven by the eruption of twisted closed magnetic field carrying a small-scale filament, which they call a 'minifilament', and that the jet was produced by reconnection of the erupting field with surrounding open field. In this study, we carry out a more extensive examination of polar coronal jets. From 180 hours of XRT polar coronal hole observations spread over two years (2014-2016), we identified 130 clearly-identifiable X-ray jet events and thus determined an event rate of over 17 jets per day per in the Hinode/XRT field of view. From the broader set, we selected 25 of the largest and brightest events for further study in AIA 171, 193, 211, and 304 Angstrom images. We find that at least the majority of the jets follow the minifilament-eruption scenario, although for some cases the evolution of the minifilament in the onset of its eruption is more complex than presented in the simplified schematic of Sterling et al. (2015). For all cases in which we could make a clear determination, the spire of the X-ray jet drifted laterally away from the jet-base-edge bright point; this spire drift away from the bright point is consistent with expectations of the minifilament-eruption scenario for coronal-jet production. This work was supported with funding from the NASA/MSFC Hinode Project Office, and from the NASA HGI program.

  3. Segmentation of Coronal Holes Using Active Contours Without Edges

    Science.gov (United States)

    Boucheron, L. E.; Valluri, M.; McAteer, R. T. J.

    2016-10-01

    An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. The detection and characterization of these regions is important for testing theories of their formation and evolution, and also from a space weather perspective because they are the source of the fast solar wind. Coronal holes are detected in full-disk extreme ultraviolet (EUV) images of the corona obtained with the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). The proposed method detects coronal boundaries without determining any fixed intensity value in the data. Instead, the active contour segmentation employs an energy-minimization in which coronal holes are assumed to have more homogeneous intensities than the surrounding active regions and quiet Sun. The segmented coronal holes tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind observations, and qualitatively match the coronal holes segmented by other methods. The means to identify a coronal hole without specifying a final intensity threshold may allow this algorithm to be more robust across multiple datasets, regardless of data type, resolution, and quality.

  4. Segmentation of Coronal Holes Using Active Contours Without Edges

    Science.gov (United States)

    Boucheron, L. E.; Valluri, M.; McAteer, R. T. J.

    2016-09-01

    An application of active contours without edges is presented as an efficient and effective means of extracting and characterizing coronal holes. Coronal holes are regions of low-density plasma on the Sun with open magnetic field lines. The detection and characterization of these regions is important for testing theories of their formation and evolution, and also from a space weather perspective because they are the source of the fast solar wind. Coronal holes are detected in full-disk extreme ultraviolet (EUV) images of the corona obtained with the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA). The proposed method detects coronal boundaries without determining any fixed intensity value in the data. Instead, the active contour segmentation employs an energy-minimization in which coronal holes are assumed to have more homogeneous intensities than the surrounding active regions and quiet Sun. The segmented coronal holes tend to correspond to unipolar magnetic regions, are consistent with concurrent solar wind observations, and qualitatively match the coronal holes segmented by other methods. The means to identify a coronal hole without specifying a final intensity threshold may allow this algorithm to be more robust across multiple datasets, regardless of data type, resolution, and quality.

  5. Estudio de caso

    OpenAIRE

    Maciel-González-Durán, Gabriela

    2015-01-01

    El presente trabajo es un estudio de caso de acompañamiento emocional y psicoterapéutico. Se muestra el contexto general y el proceso de la consultante. El motivo principal de consulta fue una experiencia de secuestro y violación que ocasionó un cuadro de estrés post-traumático. Dentro del apartado del estudio de caso se hace referencia a las vivencias, significados y contexto de la consultante, se pretende demostrar el desarrollo que se fue llevando a cabo en la consultante, y se comparten f...

  6. SAUSAGE OSCILLATIONS OF CORONAL PLASMA STRUCTURES

    Energy Technology Data Exchange (ETDEWEB)

    Nakariakov, V. M.; Hornsey, C. [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Melnikov, V. F., E-mail: V.Nakariakov@warwick.ac.uk [Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences, 196140 St Petersburg (Russian Federation)

    2012-12-20

    The dependence of the period of sausage oscillations of coronal loops on length together with the depth and steepness of the radial profile are determined. We performed a parametric study of linear axisymmetric fast magnetoacoustic (sausage) oscillations of coronal loops modeled as a field-aligned low-{beta} plasma cylinder with a smooth inhomogeneity of the plasma density in the radial direction. The density decreases smoothly in the radial direction. Sausage oscillations are impulsively excited by a perturbation of the radial velocity, localized at the cylinder axis and with a harmonic dependence on the longitudinal coordinate. The initial perturbation results in either a leaky or a trapped sausage oscillation, depending upon whether the longitudinal wavenumber is smaller or greater than a cutoff value, respectively. The period of the sausage oscillations was found to always increase with increasing longitudinal wavelength, with the dependence saturating in the long-wavelength limit. Deeper and steeper radial profiles of the Alfven speed correspond to more efficient trapping of sausage modes: the cutoff value of the wavelength increases with the steepness and the density (or Alfven speed) contrast ratio. In the leaky regime, the period is always longer than the period of a trapped mode of a shorter wavelength in the same cylinder. For shallow density profiles and shorter wavelengths, the period increases with wavelength. In the long-wavelength limit, the period becomes independent of the wavelength and increases with the depth and steepness of the radial profile of the Alfven speed.

  7. Modified Homogeneous Data Set of Coronal Intensities

    Science.gov (United States)

    Dorotovič, I.; Minarovjech, M.; Lorenc, M.; Rybanský, M.

    2014-07-01

    The Astronomical Institute of the Slovak Academy of Sciences has published the intensities, recalibrated with respect to a common intensity scale, of the 530.3 nm (Fe xiv) green coronal line observed at ground-based stations up to the year 2008. The name of this publication is Homogeneous Data Set (HDS). We have developed a method that allows one to successfully substitute the ground-based observations by satellite observations and, thus, continue with the publication of the HDS. For this purpose, the observations of the Extreme-ultraviolet Imaging Telescope (EIT), onboard the Solar and Heliospheric Observatory (SOHO) satellite, were exploited. Among other data the EIT instrument provides almost daily 28.4 nm (Fe xv) emission-line snapshots of the corona. The Fe xiv and Fe xv data (4051 observation days) taken in the period 1996 - 2008 have been compared and good agreement was found. The method to obtain the individual data for the HDS follows from the correlation analysis described in this article. The resulting data, now under the name of Modified Homogeneous Data Set (MHDS), are identical up to 1996 to those in the HDS. The MHDS can be used further for studies of the coronal solar activity and its cycle. These data are available at http://www.suh.sk.

  8. Analytical investigations on the Coronation Gospels manuscript

    Science.gov (United States)

    Aceto, Maurizio; Agostino, Angelo; Fenoglio, Gaia; Idone, Ambra; Crivello, Fabrizio; Griesser, Martina; Kirchweger, Franz; Uhlir, Katharina; Puyo, Patricia Roger

    2017-01-01

    The Coronation Gospels or Krönungsevangeliar is a manuscript kept in Vienna at the Kunsthistorisches Museum Wien, datable to the end of VIII century A.D. and produced at Charlemagne court. It is an example of a purple codex, i.e. its parchment is coloured in purple. It has to be considered as one of the most important medieval codices, according to its use to take oath in the coronation ceremony of kings and emperors of the Holy Roman Empire up to 1792. In order to gather information of the manufacture of the manuscript and its present conservation state, a diagnostic investigation campaign has been carried out in situ with totally non-invasive techniques. X-ray Fluorescence Spectrometry (XRF), UV-visible diffuse reflectance spectrophotometry with optical fibres (FORS), spectrofluorimetry, optical microscopy and multispectral analysis have been applied in order to identify the colourants used in the decoration of the manuscript, with the main concern to the dye used to impart the purple hue to the parchment. The information collected was useful in order to address some of the questions raised by art historians concerning its history.

  9. Energetics of Solar Coronal Mass Ejections

    CERN Document Server

    Subramanian, P; Subramanian, Prasad; Vourlidas, Angelos

    2007-01-01

    Aims: To investigate if solar coronal mass ejections are driven mainly by coupling to the ambient solar wind, or through the release of internal magnetic energy. Methods: We examine the energetics of 39 flux-rope like coronal mass ejections (CMEs) from the Sun using data in the distance range $\\sim$ 2--20 $R_{{\\o}dot}$ from the Large Angle Spectroscopic Coronograph (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). This comprises a complete sample of the best examples of flux-rope CMEs observed by LASCO in 1996-2001. Results: We find that 69% of the CMEs in our sample experience a clearly identifiable driving power in the LASCO field of view. For these CMEs which are driven, we examine if they might be deriving most of their driving power by coupling to the solar wind. We do not find conclusive evidence in favor of this hypothesis. On the other hand, we find that their internal magnetic energy is a viable source of the required driving power. We have estimated upper and lower limits on the power th...

  10. A Moreton Wave and its Coronal Counterparts

    Science.gov (United States)

    Francile, Carlos N.; Mandrini, Cristina H.; Long, David; Cremades, Hebe; Lopez, Fernando M.; Luoni, Maria Luisa

    2016-07-01

    On 29 March 2014, a Moreton wave was detected in AR 12017 with the Halpha Solar Telescope for Argentina (HASTA) in association with an X1 flare. Several phenomena took place in various regimes in connection with this event, such as low coronal waves and a coronal mass ejection (CME). We investigate their role and relationship with the Moreton wave to shed light on issues so far under debate. We analyze its connection with waves observed in the low corona with the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory (SDO/AIA), as well as with the ensuing CME, via kinematics analyses. We build stack plots from sequences of images obtained at different wavelengths to track wave fronts along several directions and find links between the features observed in the chromosphere and low corona, as well as in the associated CME. We also derive the shock front properties. We propose a geometrical model of the wave to explain the observed wave fronts as the photospheric and chromospheric traces of an expanding and outward-traveling bubble intersecting the Sun.

  11. Solar Wind Associated with Near Equatorial Coronal Hole

    Indian Academy of Sciences (India)

    M. Hegde; K. M. Hiremath; Vijayakumar H. Doddamani; Shashanka R. Gurumath

    2015-09-01

    Present study probes temporal changes in the area and radiative flux of near equatorial coronal hole associated with solar wind parameters such as wind speed, density, magnetic field and temperature. Using high temporal resolution data from SDO/AIA for the two wave-lengths 193 Å and 211 Å, area and radiative flux of coronal holes are extracted and are examined for the association with high speed solar wind parameters. We find a strong association between different parameters of coronal hole and solar wind. For both the wavelength bands, we also compute coronal hole radiative energy near the earth and it is found to be of similar order as that of solar wind energy. However, for the wavelength 193 Å, owing to almost similar magnitudes of energy emitted by coronal hole and energy due to solar wind, it is conjectured that solar wind might have originated around the same height where 193 Å line is formed in the corona.

  12. Observing Episodic Coronal Heating Events Rooted in Chromospheric Activity

    CERN Document Server

    McIntosh, Scott W

    2009-01-01

    We present results of a multi-wavelength study of episodic plasma injection into the corona of AR 10942. We exploit long-exposure images of the Hinode and Transition Region and Coronal Explorer (TRACE) spacecraft to study the properties of faint, episodic, "blobs" of plasma that are propelled upward along coronal loops that are rooted in the AR plage. We find that the source location and characteristic velocities of these episodic upflow events match those expected from recent spectroscopic observations of faint coronal upflows that are associated with upper chromospheric activity, in the form of highly dynamic spicules. The analysis presented ties together observations from coronal and chromospheric spectrographs and imagers, providing more evidence of the connection of discrete coronal mass heating and injection events with their source, dynamic spicules, in the chromosphere.

  13. Stellar Coronal Response to Differential Rotation and Flux Emergence

    CERN Document Server

    Gibb, G P S; Jardine, M M; Yeates, A R

    2016-01-01

    We perform a numerical parameter study to determine what effect varying differential rotation and flux emergence has on a star's non-potential coronal magnetic field. In particular we consider the effects on the star's surface magnetic flux, open magnetic flux, mean azimuthal field strength, coronal free magnetic energy, coronal heating and flux rope eruptions. To do this, we apply a magnetic flux transport model to describe the photospheric evolution, and couple this to the non-potential coronal evolution using a magnetofrictional technique. A flux emergence model is applied to add new magnetic flux onto the photosphere and into the corona. The parameters of this flux emergence model are derived from the solar flux emergence profile, however the rate of emergence can be increased to represent higher flux emergence rates than the Sun's. Overall we find that flux emergence has a greater effect on the non-potential coronal properties compared to differential rotation, with all the aforementioned properties incr...

  14. Propuesta de protocolo de abordaje de mujeres víctimas de delitos sexuales que son atendidas en la sección clínica médico forense y en las unidades médico legales del departamento de medicina legal del Organismo de Investigación Judicial Poder Judicial - Costa Rica

    Directory of Open Access Journals (Sweden)

    Micxy Trejos Romanini

    2014-12-01

    Full Text Available Los delitos sexuales constituyen uno de los motivos de consulta más comunes en la Sección Clínica Médico Forense y en las Unidades Médico Legales del Departamento de Medicina Legal del Organismo de Investigación Judicial del Poder Judicial de Costa Rica y a la fecha no se cuenta con un protocolo formal de abordaje para la valoración de éstos. La elaboración de un protocolo forense de abordaje de víctimas de delitos sexuales en sí mismo tiene algunos beneficios nada despreciables entre ellos: fomentar la minimización de errores en el proceso de recolección de datos y evidencia, recolectar adecuadamente la información permitiendo la realización de estudios prospectivos, promoviendo con todo lo anteriormente señalado la elaboración de un Dictamen Médico Legal de calidad.

  15. An Estimate of Solar Wind Velocity Profiles in a Coronal Hole and Coronal Streamer Area (6-40R)

    Science.gov (United States)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Using the total electron content data obtained by the Ulysses Solar Corona Experiment during the first solar conjunction in summer 1991 (Bird et al., 1994), an estimate is presented of solar wind velocity profiles in a coronal hole and a coronal streamer area in the range between 6 and 40 solar radii.

  16. Retrato de estudio. Sacerdote.

    OpenAIRE

    Ansede y Juanes

    2010-01-01

    1 fot.; papel; imagen 12,6 x 20 cm. - Retrato de estudio. Sacerdote. (2 copias. Gelatina D. O. P. mate montada sobre cartulina, medida total 12,6 x 20. Sello troquelado impreso del fotógrafo con letras doradas en ángulo inferior derecho de cartulina: "Ansede y Juanes - Salamanca"). - Procedencia: fondo Miguel de Unamuno. - Buena Conservación.

  17. de estudios observacionales

    Directory of Open Access Journals (Sweden)

    Erik von Elm

    2008-01-01

    un documento de explicación y elaboración al que puede accederse libremente en los sitios web de PLoS Medicine, Annals of Internal Medicine y Epidemiology. Esperamos que la declaración STROBE contribuya a mejorar la calidad de la publicación de los estudios observacionales.

  18. Resumen estudios sobre tabaquismo

    OpenAIRE

    Gónzalez, M.M. (M.)

    2009-01-01

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

  19. Abordaje supracerebeloso transtentorial suprameatal a la totalidad de la región mediobasal del lóbulo temporal

    OpenAIRE

    Quilis Quesada, Vicent

    2015-01-01

    La región mediobasal del lóbulo temporal (RMT), por su compleja anatomía y su localización, constituye a día de hoy un reto neuroquirúrgico de primer orden. El desarrollo de la cirugía microquirúrgica de base craneal y los nuevos horizontes de la cirugía endoscópica siguen sin ofrecer un abordaje óptimo para aquellas lesiones asentadas en la totalidad de la RMT (principalmente oncológicas y vasculares). La exposición parcial de la RMT y el compromiso de estructuras neurovasculares no implica...

  20. Factores emocionales en el abordaje de las enfermedades cardiovasculares. Valoración actualizada desde la Psicocardiología

    OpenAIRE

    Teresa Rodríguez Rodríguez

    2012-01-01

    El tratamiento de las enfermedades cardiovasculares exige un abordaje desde la multidisciplinariedad, por la presencia de diversos factores en su origen y evolución. La Psicocardiología se encarga de estudiar los factores de orden psicológico vinculados a estas enfermedades. En el presente trabajo se abordan los factores emocionales que repercuten en diferentes padecimientos coronarios, así como el vínculo de estos, con los diferentes tipos de personalidad. Se exponen resultados obtenidos so...

  1. ANÁLISIS DE FACTORES PROTECTORES EN EL ABORDAJE DEL MALTRATO INFANTIL DESDE LA MIRADA CLÍNICA

    OpenAIRE

    Gabriela Morelato; Silvina Giménez; José María Vitaliti; Leandro Casari; Georgina Soria

    2015-01-01

    El objetivo de este trabajo fue explorar desde una mirada clínica la presencia de los factoresprotectores necesarios para otorgar el alta en un proceso terapéutico de casos de maltrato in-fantil confirmados, según la opinión de los profesionales especialistas en su abordaje. Desdela perspectiva cualitativa, se utilizó una muestra no probabilística ocasional constituida por 51médicos, psicólogos, trabajadores sociales y otras disciplinas afines, especialistas en el abordajede casos de maltrato...

  2. Observaciones de la corona solar interior con un coronógrafo de espejo

    Science.gov (United States)

    Stenborg, G.; Schwenn, R.; Francile, C.; Rovira, M.

    El plasma de la corona solar es un buen indicador de las líneas de fuerza del campo magnético. Por lo tanto, el análisis de estructuras coronales cuasiestacionarias en la corona da importante información sobre el campo magnético y la actividad asociada. Se trata de poner límites a los modelos teóricos existentes mediante el estudio de distintas estructuras en la corona interior. En agosto de 1997 comenzó a operar el coronógrafo solar (MICA) en El Leoncito como parte del Observatorio Solar Alemán-Argentino. Desde su instalación obtiene imágenes de la corona solar (1.05 a 2.0 radios solares) en 2 líneas espectrales correspondientes a la emisión de Fe XIV y Fe X. El instrumento puede obtener imágenes cada minuto por lo que es ideal para estudiar procesos rápidos. Presentamos observaciones recientes que muestran la capacidad del coronógrafo así como la evolución de algunos eventos dinámicos observados por MICA.

  3. Abordajes clínicos de las problemáticas actuales en la infancia.

    Directory of Open Access Journals (Sweden)

    Alicia Muniz Martoy

    2013-11-01

    Full Text Available El presente artículo ofrece algunas reflexiones en torno a la experiencia clínica con niños y sus familias en el Uruguay actual tomando algunos autores de diversas disciplinas. Se plantea la importancia de considerar las condiciones de producción de subjetividad que inciden en los modos de presentación de los niños y sus dificultades en diversas áreas. Asimismo se plantean cuestiones en torno a las instituciones involucradas en estos procesos de subjetivación como lo son la Familia, la Escuela y la Salud, con sus discursos, padecimientos y prácticas actuales. Se observan las estrategias de abordaje en psicología clínica enmarcadas en las prestaciones de salud mental, advirtiendo efectos reduccionistas sobre la compleja situación de los niños cuyas conductas se patologizan a la luz de las exigencias epocales. Se propone para la psicología clínica una concepción del diagnóstico como acto promotor de sentido nuevo y preventivo de estigmatización y exclusión. This paper provides some reflections on the clinical experience with children and their families today in Uruguay, taking some authors from various disciplines. The importance of considering the conditions involving the production of subjectivity that affects the way children express their difficulties in various areas, is raised. This paper also raises questions about the institutions involved in these processes of subjectification such as the Family, the School and the Health, with their current speeches, sufferings and practices. Clinical psychology approach strategies that are framed in mental health benefits are observed and the reductive effects on the complex situation of children whose behavior is pathologized in the light of current demands is taken into consideration. A conception of diagnosis as a promoter act of new meaning and as having a preventive effect on the stigmatization and exclusion is proposed for clinical psychology.

  4. Programas de ocio activo e infraestructura de esparcimiento (como elementos protectores en los estudios sobre violencia escolar

    Directory of Open Access Journals (Sweden)

    Ciria Salazar

    2016-01-01

    Full Text Available El presente texto hace una revisión de estudios y trabajos en América Latina, México y Colima sobre los aportes de las categorías ocio activo e infraestructura de esparcimiento en los estudios descriptivos y explicativos sobre violencia escolar. Incluirlos permitirá observar más allá de las dinámicas áulicas formales, pues podemos estudiar las relaciones, rupturas y crisis que se construyen en el patio, la cancha y las instalaciones comunitarias, así como los programas de esparcimiento en cada uno de los espacios mencionados. Ello ofrece la posibilidad de encontrar nuevos abordajes para trazar puentes seguros de convivencia e instalar una verdadera cultura de paz en la comunidad.

  5. Magnetic structure of Coronal Mass Ejections

    CERN Document Server

    Lyutikov, Maxim

    2012-01-01

    We present several models of the magnetic structure of solar coronal mass ejections (CMEs). First, we model CMEs as expanding force-free magnetic structures. While keeping the internal magnetic field structure of the stationary solutions, expansion leads to complicated internal velocities and rotation, while the field structures remain force-free. Second, expansion of a CME can drive resistive dissipation within the CME changing the ionization states of different ions. We fit in situ measurements of ion charge states to the resistive spheromak solutions. Finally, we consider magnetic field structures of fully confined stable magnetic clouds containing both toroidal and poloidal magnetic fields and having no surface current sheets. Expansion of such clouds may lead to sudden onset of reconnection events.

  6. Coronal Mass Ejections: From Sun to Earth

    Science.gov (United States)

    Patsourakos, S.

    2016-06-01

    Coronal Mass Ejections (CMEs) are gigantic expulsions of magnetized plasmas from the solar corona into the interplanetary (IP) space. CMEs spawn ~ 1015 gr of mass and reach speeds ranging between several hundred to a few thousand km/s (e.g., Gopalswamy et al. 2009; Vourlidas et al. 2010). It takes 1-5 days for a CME to reach Earth. CMEs are one of the most energetic eruptive manifestations in the solar system and are major drivers of space weather via their magnetic fields and energetic particles, which are accelerated by CME-driven shocks. In this review we give a short account of recent, mainly observational, results on CMEs from the STEREO and SDO missions which include the nature of their pre-eruptive and eruptive configurations and the CME propagation from Sun to Earth. We conclude with a discussion of the exciting capabilities in CME studies that will soon become available from new solar and heliospheric instrumentation.

  7. Coronal Neutrino Emission in Hypercritical Accretion Flows

    CERN Document Server

    Kawabata, R; Kawanaka, N

    2007-01-01

    Hypercritical accretion flows onto stellar mass black holes (BHs) are commonly considered as a promising model of central engines of gamma-ray bursts (GRBs). In this model a certain fraction of gravitational binding energy of accreting matter is deposited to the energy of relativistic jets via neutrino annihilation and/or magnetic fields. However, some recent studies have indicated that the energy deposition rate by neutrino annihilation is somewhat smaller than that needed to power a GRB. To overcome this difficulty, Ramirez-Ruiz & Socrates (2005) proposed that high energy neutrinos from hot corona above the accretion disk might enhance the efficiency of energy deposition. We elucidate the disk corona model in the context of hypercritical accretion flows. From the energy balance in the disk and the corona, we can calculate the disk and coronal temperature, Td and Tc, and neutrino spectra, taking into account the neutrino cooling processes by neutrino-electron scatterings and neutrino pair productions. Th...

  8. A magnetohydrodynamic theory of coronal loop transients

    Science.gov (United States)

    Yeh, T.

    1982-01-01

    The physical and geometrical characteristics of solar coronal loop transients are described in an MHD model based on Archimedes' MHD buoyancy force. The theory was developed from interpretation of coronagraphic data, particularly from Skylab. The brightness of a loop is taken to indicate the electron density, and successive pictures reveal the electron enhancement in different columns. The forces which lift the loop off the sun surface are analyzed as an MHD buoyancy force affecting every mass element by imparting an inertial force necessary for heliocentrifugal motion. Thermal forces are responsible for transferring the ambient stress to the interior of the loop to begin the process. The kinematic and hydrostatic buoyancy overcome the gravitational force, and a flux rope can then curve upward, spiralling like a corkscrew with varying cross section around the unwinding solar magnetic field lines.

  9. Periodicities in Solar Coronal Mass Ejections

    CERN Document Server

    Lou, Y Q; Fan, Z; Wang, S; Wang, J

    2003-01-01

    Mid-term quasi-periodicities in solar coronal mass ejections (CMEs) during the most recent solar maximum cycle 23 are reported here for the first time using the four-year data (February 5, 1999 to February 10, 2003) of the Large Angle Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). In parallel, mid-term quasi-periodicities in solar X-ray flares (class >M5.0) from the Geosynchronous Operational Environment Satellites (GOES) and in daily averages of Ap index for geomagnetic disturbances from the World Data Center (WDC) at the International Association for Geomagnetism and Aeronomy (IAGA) are also examined for the same four-year time span. Several conceptual aspects of possible equatorially trapped Rossby-type waves at and beneath the solar photosphere are discussed.

  10. Kinematical properties of coronal mass ejections

    CERN Document Server

    Temmer, Manuela

    2016-01-01

    Coronal mass ejections (CMEs) are the most dynamic phenomena in our solar system. They abruptly disrupt the continuous outflow of solar wind by expelling huge clouds of magnetized plasma into interplanetary space with velocities enabling to cross the Sun-Earth distance within a few days. Earth-directed CMEs may cause severe geomagnetic storms when their embedded magnetic fields and the shocks ahead compress and reconnect with the Earth's magnetic field. The transit times and impacts in detail depend on the initial CME velocity, size, and mass, as well as on the conditions and coupling processes with the ambient solar wind flow in interplanetary space. The observed CME parameters may be severly affected by projection effects and the constant changing environmental conditions are hard to derive. This makes it difficult to fully understand the physics behind CME evolution, preventing to do a reliable forecast of Earth-directed events. This short review focusing on observational data, shows recent methods which w...

  11. Solar Eruptions: Coronal Mass Ejections and Flares

    Science.gov (United States)

    Gopalswamy, Nat

    2012-01-01

    This lecture introduces the topic of Coronal mass ejections (CMEs) and solar flares, collectively known as solar eruptions. During solar eruptions, the released energy flows out from the Sun in the form of magnetized plasma and electromagnetic radiation. The electromagnetic radiation suddenly increases the ionization content of the ionosphere, thus impacting communication and navigation systems. Flares can be eruptive or confined. Eruptive flares accompany CMEs, while confined flares hav only electromagnetic signature. CMEs can drive MHD shocks that accelerate charged particles to very high energies in the interplanetary space, which pose radiation hazard to astronauts and space systems. CMEs heading in the direction of Earth arrive in about two days and impact Earth's magnetosphere, producing geomagnetic storms. The magnetic storms result in a number of effects including induced currnts that can disrupt power grids, railroads, and underground pipelines

  12. Transverse Oscillations in a Coronal Loop Triggered by a Jet

    Science.gov (United States)

    Sarkar, S.; Pant, V.; Srivastava, A. K.; Banerjee, D.

    2016-11-01

    We detect and analyse transverse oscillations in a coronal loop, lying at the south-east limb of the Sun as seen from the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The jet is believed to trigger transverse oscillations in the coronal loop. The jet originates from a region close to the coronal loop on 19 September 2014 at 02:01:35 UT. The length of the loop is estimated to be between 377 - 539 Mm. Only one complete oscillation is detected with an average period of about 32±5 min. Using magnetohydrodynamic (MHD) seismologic inversion techniques, we estimate the magnetic field inside the coronal loop to be between 2.68 - 4.5 G. The velocity of the hot and cool components of the jet is estimated to be 168 km s^{-1} and 43 km s^{-1}, respectively. The energy density of the jet is found to be greater than the energy density of the oscillating coronal loop. We therefore conclude that the jet triggered transverse oscillations in the coronal loop. To our knowledge, this is the first coronal loop seismology study using the properties of a jet propagation to trigger oscillations.

  13. Coronal loops above an Active Region - observation versus model

    CERN Document Server

    Bourdin, Philippe-A; Peter, Hardi

    2014-01-01

    We conducted a high-resolution numerical simulation of the solar corona above a stable active region. The aim is to test the field-line braiding mechanism for a sufficient coronal energy input. We also check the applicability of scaling laws for coronal loop properties like the temperature and density. Our 3D-MHD model is driven from below by Hinode observations of the photosphere, in particular a high-cadence time series of line-of-sight magnetograms and horizontal velocities derived from the magnetograms. This driving applies stress to the magnetic field and thereby delivers magnetic energy into the corona, where currents are induced that heat the coronal plasma by Ohmic dissipation. We compute synthetic coronal emission that we directly compare to coronal observations of the same active region taken by Hinode. In the model, coronal loops form at the same places as they are found in coronal observations. Even the shapes of the synthetic loops in 3D space match those found from a stereoscopic reconstruction ...

  14. PROMINENCE ACTIVATION BY CORONAL FAST MODE SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Takuya [Department of Astronomy, Kyoto University, Sakyo, Kyoto, 606-8502 (Japan); Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shibata, Kazunari, E-mail: takahashi@kwasan.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2015-03-01

    An X5.4 class flare occurred in active region NOAA11429 on 2012 March 7. The flare was associated with a very fast coronal mass ejection (CME) with a velocity of over 2500 km s{sup −1}. In the images taken with the Solar Terrestrial Relations Observatory-B/COR1, a dome-like disturbance was seen to detach from an expanding CME bubble and propagated further. A Type-II radio burst was also observed at the same time. On the other hand, in extreme ultraviolet images obtained by the Solar Dynamic Observatory/Atmospheric Imaging Assembly (AIA), the expanding dome-like structure and its footprint propagating to the north were observed. The footprint propagated with an average speed of about 670 km s{sup −1} and hit a prominence located at the north pole and activated it. During the activation, the prominence was strongly brightened. On the basis of some observational evidence, we concluded that the footprint in AIA images and the ones in COR1 images are the same, that is, the MHD fast mode shock front. With the help of a linear theory, the fast mode Mach number of the coronal shock is estimated to be between 1.11 and 1.29 using the initial velocity of the activated prominence. Also, the plasma compression ratio of the shock is enhanced to be between 1.18 and 2.11 in the prominence material, which we consider to be the reason for the strong brightening of the activated prominence. The applicability of linear theory to the shock problem is tested with a nonlinear MHD simulation.

  15. The Dynamics of Coronal-Hole Boundaries

    Science.gov (United States)

    Higginson, A. K.; Antiochos, S. K.; DeVore, C. R.; Wyper, P. F.; Zurbuchen, T.

    2015-12-01

    The source of the slow solar wind at the Sun is the subject of intense debate in solar and heliospheric physics. Because the majority of the solar wind observed at Earth is slow wind, understanding its origin is essential for understanding and predicting Earth's space weather environment. In-situ and remote observations show that, compared to the fast wind, the slow solar wind corresponds to higher freeze-in temperatures, as indicated by charge-state ratios, and more corona-like elemental abundances. These results indicate that the most likely source for the slow wind is the hot plasma in the closed-field corona; however, the release mechanism for the wind from the closed-field regions is far from understood. Here we present the first fully dynamic, 3D MHD simulations of a coronal-hole boundary driven by photospheric convective flows. We determine in detail the opening and closing of coronal flux due to photospheric motions at the base of a helmet streamer. These changes should lead to the release of plasma from the closed magnetic field at the edge of the streamer. Our analysis demonstrates that the bulk of the release is due to interchange reconnection. We calculate the effective of numerical Lundquist number on the dynamics and discuss the implications of our results for theories of slow-wind origin, in particular the S-Web model. We also discuss the implications of our results for observations, in particular from the upcoming Solar Orbiter and Solar Probe Plus missions. This work was supported by the NASA SR&T and TR&T Programs.

  16. Numerical Simulation of DC Coronal Heating

    Science.gov (United States)

    Dahlburg, Russell B.; Einaudi, G.; Taylor, Brian D.; Ugarte-Urra, Ignacio; Warren, Harry; Rappazzo, A. F.; Velli, Marco

    2016-05-01

    Recent research on observational signatures of turbulent heating of a coronal loop will be discussed. The evolution of the loop is is studied by means of numerical simulations of the fully compressible three-dimensional magnetohydrodynamic equations using the HYPERION code. HYPERION calculates the full energy cycle involving footpoint convection, magnetic reconnection, nonlinear thermal conduction and optically thin radiation. The footpoints of the loop magnetic field are convected by random photospheric motions. As a consequence the magnetic field in the loop is energized and develops turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets: energy is deposited at small scales where heating occurs. Dissipation is non-uniformly distributed so that only a fraction of thecoronal mass and volume gets heated at any time. Temperature and density are highly structured at scales which, in the solar corona, remain observationally unresolved: the plasma of the simulated loop is multi thermal, where highly dynamical hotter and cooler plasma strands are scattered throughout the loop at sub-observational scales. Typical simulated coronal loops are 50000 km length and have axial magnetic field intensities ranging from 0.01 to 0.04 Tesla. To connect these simulations to observations the computed number densities and temperatures are used to synthesize the intensities expected in emission lines typically observed with the Extreme ultraviolet Imaging Spectrometer (EIS) on Hinode. These intensities are then employed to compute differential emission measure distributions, which are found to be very similar to those derived from observations of solar active regions.

  17. Mulierismo Y teoría social. Un abordaje de los estudios de género desde la crítica de las ciencias sociales

    Directory of Open Access Journals (Sweden)

    María del Refugio Navarro Hernández

    2015-01-01

    Full Text Available Ante los cambios que han sufrido las ciencias sociales, frente a los ataques feministas en los últimos cuarenta años de desempeño intelectual de grupos muy importantes en los países desarrollados, es necesario analizar en qué si - tuación observamos la efectividad del mulierismo y el feminismo como una confluencia histórica que está mostrando un nuevo paradigma, estructuras, etc., dentro de las ciencias sociales que, primero se convierte en crítica, y luego, en transformaciones de ajustes y cambios, etc., probablemente, nos muestren otros referentes de las relaciones hombre-mujer que se están configurando bajo combinaciones que, seguramente, definirán las futuras construcciones epistémicas que comprenderán las nuevas sociedades. La crítica a las ciencias sociales desde la feminidad es una nueva perspectiva, tanto en la incidencia que tiene en el género, como en los mecanismos de trasgresión y avance en las relaciones sociales entre los sexos.

  18. Acción COST Femicide Across Europe, un espacio de cooperación trasnacional para el estudio y el abordaje del feminicidio en Europa

    Directory of Open Access Journals (Sweden)

    Belén Sanz-Barbero

    2016-09-01

    Full Text Available El feminicidio o asesinato de mujeres por razones de género es ya un reconocido problema de salud pública, además de una grave vulneración de los derechos humanos. Todavía se desconoce con exactitud su magnitud en el mundo, dadas las dificultades metodológicas para diferenciar estos asesinatos de otros homicidios de mujeres. El Programa de la Unión Europea «Redes de Cooperación Europea en Ciencia y Tecnología» puso en marcha en 2013 la Acción COST Femicide across Europe, abriendo un marco europeo óptimo para la cooperación transnacional entre personas expertas que aborden grandes retos sociales y de salud pública como el feminicidio. En esta nota de campo se describen sus principales objetivos, los grupos de expertos y expertas que lo conforman, y los resultados obtenidos a medio plazo con dicha experiencia.

  19. La acción empresarial organizada: propuesta de abordaje para el estudio del empresariado Organized business action: proposing an approach to the business community

    Directory of Open Access Journals (Sweden)

    Marina Dossi

    2011-09-01

    Full Text Available Si bien el empresariado es analizado extensamente en las ciencias sociales, el interrogante respecto a los mecanismos y los procesos que utiliza para organizar sus acciones no ha sido respondido en profundidad. En el caso de los empresarios, la acción se canaliza a través de sus organizaciones representativas. Producida dentro de estas asociaciones, y considerada como tipo de acción política y subtipo de acción colectiva, la propuesta de este trabajo es elaborar y presentar el concepto de acción empresarial organizada.Although the business community has been extensively analyzed in the social sciences, the question about the mechanisms and processes that it uses to organize its actions has not been fully answered. In the case of businessmen, actions are channeled through their representative organizations. Produced within these associations and regarded as a type of political action and sub-type of collective action, the aim of this paper is to draw up and present a concept of organized business action.

  20. MHD Waves and Coronal Seismology: an overview of recent results

    CERN Document Server

    De Moortel, Ineke

    2012-01-01

    Recent observations have revealed that MHD waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology which have recently been the focus of intense debate or are newly emerging. In particular, we focus on four topics: (i) the current controversy surrounding propagating intensity perturbations along coronal loops, (ii) the interpretation of propagating transverse loop oscillations, (iii) the ongoing search for coronal (torsional) Alfven waves and (iv) the rapidly developing topic of quasi-periodic pulsations (QPP) in solar flares.

  1. Magnetohydrodynamic waves and coronal seismology: an overview of recent results.

    Science.gov (United States)

    De Moortel, Ineke; Nakariakov, Valery M

    2012-07-13

    Recent observations have revealed that magnetohydrodynamic (MHD) waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology that have recently been the focus of intense debate or are newly emerging. In particular, we focus on four topics: (i) the current controversy surrounding propagating intensity perturbations along coronal loops, (ii) the interpretation of propagating transverse loop oscillations, (iii) the ongoing search for coronal (torsional) Alfvén waves, and (iv) the rapidly developing topic of quasi-periodic pulsations in solar flares.

  2. Case report: pre-eruptive intra-coronal radiolucencies revisited.

    LENUS (Irish Health Repository)

    Counihan, K P

    2012-08-01

    Pre-eruptive intra-coronal radiolucency (PEIR) describes a radiolucent lesion located in the coronal dentine, just beneath the enamel-dentine junction of unerupted teeth. The prevalence of this lesion varies depending on the type and quality of radiographic exposure and age of patients used for assessment. The aetiology of pre-eruptive intra-coronal radiolucent lesions is not fully understood, but published clinical and histological evidence suggest that these lesions are resorptive in nature. Issues around the diagnosis, treatment planning and clinical management of this lesion are explored using previously unreported cases.

  3. Formation of the current sheet in a coronal streamer

    CERN Document Server

    Abbo, Lucia; Lionello, Roberto; Mikić, Zoran; Riley, Pete

    2011-01-01

    The present work is on the study of a coronal streamer observed in March 2008 at high spectral and spatial resolution by the Ultraviolet Coronagraph Spectrometer (UVCS) onboard SOHO. On the basis of a spectroscopic analysis of the O VI doublet, the solar wind plasma parameters are inferred in the extended corona. The analysis accounts for the coronal magnetic topology, extrapolated through a 3D magneto-hydrodynamic model. The results of the analysis show indications on the formation of the current sheet, one of the source regions of the slow coronal wind.

  4. DOCUMENTO: EL ABORDAJE DE LA PROBLEMÁTICA DE EXPLOTACIÓN SEXUAL INFANTIL EN CARTAGENA

    OpenAIRE

    Mabel Valencia Mosquera; Carlos Ospina Bozzi

    2005-01-01

    Este documento muestra el contexto en el cual se está desarrollando en Cartagena la problemática de la explotación sexual infantil, los estudios e intervenciones que se han venido adelantando para buscar solución a la problemática. De otra parte presenta apartes de una propuesta educativa que apunta a la responsabilidad social que la ciudadanía, entes gubernamentales y ONGs deben asumir en la erradicación del fenómeno.

  5. DOCUMENTO: EL ABORDAJE DE LA PROBLEMÁTICA DE EXPLOTACIÓN SEXUAL INFANTIL EN CARTAGENA

    Directory of Open Access Journals (Sweden)

    Mabel Valencia Mosquera

    2005-08-01

    Full Text Available Este documento muestra el contexto en el cual se está desarrollando en Cartagena la problemática de la explotación sexual infantil, los estudios e intervenciones que se han venido adelantando para buscar solución a la problemática. De otra parte presenta apartes de una propuesta educativa que apunta a la responsabilidad social que la ciudadanía, entes gubernamentales y ONGs deben asumir en la erradicación del fenómeno.

  6. SALUD MENTAL: UN ABORDAJE DESDE LA PERSPECTIVA ACTUAL DE LA PSICOLOGÍA DE LA SALUD

    OpenAIRE

    Moisés Mebarak; Alberto De Castro; María del Pilar Salamanca; María Fernanda Quintero

    2009-01-01

    Este artículo está basado en un estudio estado del arte acerca del entendimiento actual que se tiene sobre el concepto de salud mental, especialmente desde la perspectiva de la psicología de la salud. Con el fin de ilustrar este campo, se presentan algunos aportes y/o investigaciones tanto a nivel general como de la región costa Caribe colombiana. Se ha encontrado que el concepto de salud mental implica el desarrollo de estilos de vida y de características personales, interpersonales, sociale...

  7. Un análisis crítico de las perspectivas de diálogo en la literatura sobre comunicación para el desarrollo y cambio social: abordajes y desafíos

    Directory of Open Access Journals (Sweden)

    Adriana Ángel Botero

    2011-01-01

    Full Text Available El objetivo de este estudio fue explorar la literatura producida en el campo de la comunicación para el desarrollo y el cambio social (cdsc, con el fin de: a. comprender la manera como diversos investigadores y profesionales de la comunicación han utilizado la noción de diálogo para definir, entender y apoyar los procesos de desarrollo y cambio social; b. explorar las implicaciones teóricas y prácticas de la utilización de distintos enfoques de diálogo. Después de analizar más de doscientos textos, concluimos que en el campo de la cdsc la noción de diálogo ha sido abordada, primordialmente, de tres maneras: diálogo como modelo de comunicación, diálogo como evento de comunicación interpersonal y diálogo como proceso de deliberación pública. En otras palabras, la cdsc ha definido el concepto en relación con tres escenarios: las teorías de los medios masivos de comunicación, la comunicación interpersonal y los procesos de deliberación pública. Una vez explicados dichos escenarios, presentamos los riesgos, consecuencias e implicaciones de cada uno de estos abordajes. Finalmente, exponemos algunos de los desafíos y retos que tiene la cdsc en relación con la aplicación de prácticas dialógicas. Además de ofrecer una mirada sistemática al uso de la noción de diálogo en este campo, nuestro estudio también revela limitaciones importantes en cada uno de dichos escenarios.

  8. Los beneficios de la hipoterapia y la equitación terapéutica con personas autistas : un estudio de caso

    OpenAIRE

    Bouzo González, Sonia

    2015-01-01

    El principal objetivo de este estudio ha sido determinar la eficacia y eficiencia de un programa de intervención educativa y desarrollo integral con niños y adolescentes que sufren autismo utilizando como técnica de intervención la hipoterapia y la equitación terapéutica. La hipoterapia es un área de intervención terapéutica que utiliza el caballo dentro de un abordaje interdisciplinar, tanto en los planos de la salud y el deporte como en la búsqueda incesante del bienestar físico, psíqu...

  9. Capital natural-cultural y participación social en iniciativas de ecoturismo comunitario. Estudio de caso en Quintana Roo

    OpenAIRE

    2006-01-01

    La materia de esta investigación es la participación comunitaria en proyectos de ecoturismo. En las propuestas de desarrollo alternativo, la participación es un ingrediente fundamental de apropiación y empoderamiento, para que sean las propias comunidades las que dirijan su propio destino de desarrollo. Se realizó un estudio de caso de una experiencia de diversificación productiva con base en el ecoturismo, y con la participación social como eje de análisis. El abordaje fue a través del enfoq...

  10. Aplicación de la terapia de aceptación y compromiso a un caso de crisis de angustia con agorafobia: un estudio de caso

    OpenAIRE

    Morón Gaspar, Rafael

    2005-01-01

    Se presenta el caso de un joven con crisis de angustia con agorafobia (APA, 1994) si bien se ha conceptualizado desde un punto de vista funcional como un Trastorno Evitativo Experiencial (Luciano y Hayes, 2001). La resolución del caso se ha llevado a cabo mediante la Terapia de Aceptación y Compromiso (ACT). Se aplicó en formato individual durante 9 sesiones. Los resultados obtenidos, tanto en este estudio como en otros, indica que este abordaje terapéutico es adecuado cuando se trata de u...

  11. Una perspectiva epistemológica para el estudio de las formaciones socioculturales

    Directory of Open Access Journals (Sweden)

    Ana María Castellano

    2009-01-01

    Full Text Available Este artículo presenta dos planteamientos: la propuesta del concepto de formaciones socioculturales para el estudio de comunidades locales, y una propuesta epistemológica para el abordaje de estas formaciones. Estos aspectos fueron elaborados a partir de una investigación cualitativa que implicó la revisión, clasificación, análisis e interpretación de aportes de expertos en materia sociocultural, además de la observación de campo desarrollada en diversas comunidades de la región zuliana de Venezuela. Las reflexiones finales arrojaron la necesidad de lograr un enfoque constructivo de las comunidades locales, que considere lo particular y lo singular de cada comunidad, sin desligarlo de los contextos sociales más globales.

  12. La violencia. Conceptualización y elementos para su estudio

    Directory of Open Access Journals (Sweden)

    Agustín Martínez Pacheco

    2016-01-01

    Full Text Available Este ensayo busca realizar un doble abordaje del tema de la violencia. En primer lugar se presenta una reflexión sobre el término, contraponiendo dos conceptualizaciones, una que la restringe al uso de la fuerza para causar daño y otra que la amplía considerándola como la negación del otro. Se señalan los alcances y limitaciones de cada una de estas conceptualizaciones. En segundo lugar, se abordan algunos de los elementos importantes a tomar en cuenta para su estudio, atendiendo las causas, características, consecuencias y valoraciones de diversas formas de violencia.

  13. Las neurociencias para el abordaje de la didáctica de las finanzas

    Directory of Open Access Journals (Sweden)

    Florentino Rico Calvano

    2016-01-01

    Full Text Available El presente artículo de revisión se centra en determinar cuál es el discurso de las neurociencias para el abordaje de la didáctica de las finanzas, y cuáles son las estrategias y didácticas aplicadas a la enseñabilidad de las finanzas y su correspondencia con la práctica y los modelos pedagógicos. Se identificaron teorías didácticas que fundamentarán las prácticas educativas de los docentes en la enseñabilidad, evaluando, articulando y confrontando los fundamentos pedagógicos que poseen los docentes para el desarrollo humano teniendo en cuenta el contexto. Se resalta la importancia que tiene la incorporación de los conocimientos científicos y tecnológicos en la transformación de las futuras pedagogías y didácticas. Se destaca el aporte de las neurociencias para alcanzar la excelencia en la educación con el trabajo interdisciplinar que haga compatible la educación con el funcionamiento del cerebro, y la investigación en el aula como práctica normal de la actividad docente. Se incorporan nuevas y novedosas estrategias de aprendizaje considerando las orientaciones dadas por la teoría de Ned Herrmann. Se evalúan, ejecutan y planifican propuestas didácticas acordes a los tipos de inteligencia y a los resultados de la investigación en neurociencia que permitieron saber que el cerebro conjuga el pensar, el sentir y el actuar. Se tiene claro que los contextos implican ciertas estrategias didácticas que es necesario contextualizar con el conocimiento, enfatizando sobre la realidad con utilidad social y la contextualización de los saberes. Se aprecia cómo el aprendizaje cambia la estructura física del sistema, organiza y reorganiza el cerebro, dentro de la orientación ética de emancipación humana. Abstract This essay focuses on determine what is the discourse of neuroscience to approach the teaching of finance, teaching strategies and teachability applied to finance and correspondence with the practice and teaching

  14. DESAFÍOS DIDÁCTICOS EN EL ABORDAJE DE CONTENIDOS AMBIENTALES EN LA ESCUELA MEDIA

    Directory of Open Access Journals (Sweden)

    Andrea Viviana Ajón

    2015-12-01

    Full Text Available Los contenidos ambientales en la enseñanza de la Geografía representan desde hace tiempo, un atajo de la disciplina para mostrar el espíritu renovador del temario en la escuela, a través del ingreso de nuevos conceptos y del abordaje de problemáticas de relevancia social. La inclusión de dichos contenidos en el aula expresó un giro didáctico –impulsado desde el currículum- en la medida que favoreció la revisión del peso de la geografía física en las clases, en los libros escolares y en la planificación anual del profesor. Propició el tratamiento de problemáticas en diferentes escalas, el reconocimiento de actores sociales y sus intereses, el papel del Estado y organizaciones civiles, despertando el genuino interés de los alumnos. Sin embargo, este proceso no estuvo ni está exento de preguntas, desafíos metodológicos y dificultades. Particularmente se registran tres debilidades: la abundancia de información proveniente de los medios masivos de comunicación e Internet que suele reemplazar la explicación de lo ambiental desde la geografía; la persistencia de la importancia asignada a la geografía física previo al análisis de un caso ambiental; ciertas limitaciones provenientes de la línea renovada para la enseñanza de temáticas ambientales en la escuela. Os conteúdos ambientais no ensino da geografia tem representado a algum tempo um atalho da disciplina para mostrar o espírito inovador do seu currículo na escola, através da entrada de novos conceitos e abordagem de com relevância social. A inclusão destes conteúdos na sala de aula expressou uma rotação educacional – impulsionado pelo currículo - na medida em que favoreceu a revisão do peso da geografia física nas aulas, nos livros didáticos e no planejamento anual do professor. Proporcionando o tratamento da problemática em diferentes escalas, com o reconhecimento dos atores sociais e seus interesses, e do o papel do Estado e das organizações civis

  15. Standing Slow MHD Waves in Radiatively Cooling Coronal Loops

    CERN Document Server

    Al-Ghafri, Khalil Salim

    2015-01-01

    The standing slow magneto-acoustic oscillations in cooling coronal loops are investigated. There are two damping mechanisms which are considered to generate the standing acoustic modes in coronal magnetic loops namely thermal conduction and radiation. The background temperature is assumed to change temporally due to optically thin radiation. In particular, the background plasma is assumed to be radiatively cooling. The effects of cooling on longitudinal slow MHD modes is analytically evaluated by choosing a simple form of radiative function that ensures the temperature evolution of the background plasma due to radiation coincides with the observed cooling profile of coronal loops. The assumption of low-beta plasma leads to neglect the magnetic field perturbation and eventually reduces the MHD equations to a 1D system modelling longitudinal MHD oscillations in a cooling coronal loop. The cooling is assumed to occur on a characteristic time scale much larger than the oscillation period that subsequently enables...

  16. Standing sausage modes in coronal loops with plasma flow

    CERN Document Server

    Li, Bo; Xia, Li-Dong; Yu, Hui

    2014-01-01

    Magnetohydrodynamic waves are important for diagnosing the physical parameters of coronal plasmas. Field-aligned flows appear frequently in coronal loops.We examine the effects of transverse density and plasma flow structuring on standing sausage modes trapped in coronal loops, and examine their observational implications. We model coronal loops as straight cold cylinders with plasma flow embedded in a static corona. An eigen-value problem governing propagating sausage waves is formulated, its solutions used to construct standing modes. Two transverse profiles are distinguished, one being the generalized Epstein distribution (profile E) and the other (N) proposed recently in Nakariakov et al.(2012). A parameter study is performed on the dependence of the maximum period $P_\\mathrm{max}$ and cutoff length-to-radius ratio $(L/a)_{\\mathrm{cutoff}}$ in the trapped regime on the density parameters ($\\rho_0/\\rho_\\infty$ and profile steepness $p$) and flow parameters (magnitude $U_0$ and profile steepness $u$). For e...

  17. Cyclical Variation of the Quiet Corona and Coronal Holes

    Indian Academy of Sciences (India)

    Takashi Sakurai

    2000-09-01

    Recent advances in the understanding of the quiet corona and coronal holes are reviewed. The review is based on long-term accumulation of data from eclipse observations, coronagraph observations, helium 10830 Å spectroheliograms, and X-ray observations.

  18. Jet phenomena above null points of the coronal magnetic field

    Science.gov (United States)

    Filippov, B.; Koutchmy, S.; Golub, L.

    2009-12-01

    Short-lived plasma jets of various scales, from giant X-ray jets more than 300 Mm in extent to numerous small jets with sizes typical of macrospicules, are the phenomena observed in the solar corona in extreme ultraviolet and X-ray emission. Small jets are particularly prominent in polar coronal holes. They are close neighbors of tiny bright loops and coincide in time with their sudden brightening and increase in size. The geometric shape of the jets and their location suggest that they arise near singular null points of the coronal magnetic field. These points appear in coronal holes due to the emergence of small bipolar or unipolar magnetic structures within large-scale unipolar cells. Polar jets show a distinct vertical plasma motion in a coronal hole that introduces significant momentum and mass into the solar wind flow. Investigating the dynamics of polar jets can elucidate certain details in the problem of fast solar wind acceleration.

  19. The coronal magnetic field reversal observed by the SOLARC instrument

    Institute of Scientific and Technical Information of China (English)

    LIU Yu; SHEN YuanDeng

    2009-01-01

    High-sensitivity measurements for mapping coronal magnetic field have become possible since the recent development of infrared detection techniques. One urgent task that arises from the routine infrared observations is to interpret what the Stokes signals could indicate for coronal magnetic fields. It is the first time for us to successfully reveal the coronal field structure above a simple and stable sunspot on the photosphere using profiles of full Stokes parameters. In this paper, the author further points out the deficiency in any conclusions/judgements just based on incomplete polarization data. A magnetic flux reversal feature, observed from circular polarization data, may correspond to one or more coronal tubes with their front or farside arching apex there, more complicated than people imagined before. To exactly locate the infrared radiation sources, we need both circular and linear polarization data for an integrated analysis of them.

  20. Anticipating the Geoeffectiveness of Coronal Mass Ejections Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Coronal Mass Ejections (CMEs) are responsible for some of the most severe space weather at Earth. Major geomagnetic storms arise when CMEs carry large amounts of...

  1. El abordaje estatal de la pobreza en Programas de Transferencias Monetarias Condicionadas

    Directory of Open Access Journals (Sweden)

    Rebeca Cena

    2015-02-01

    Full Text Available El presente texto tiene por objetivo contribuir al estudio, análisis y comprensión de los mecanismos de estructuración social del capitalismo actual mediante los Programas de Transferencias Monetarias Condicionadas (PTMC dirigidos a niños, niñas y adolescentes “pobres”, con base en la experiencia de cuatro países del Cono Sur: Argentina, Bolivia, Brasil y Chile. Nos centramos en el estudio del diseño de los PTMC de alcance nacional vigentes en el período 2009-2013, para considerar algunos indicios sobre cómo se concibe y construye la “niñez” en los sectores más pobres desde la mirada estatal, y analizar críticamente qué formas toma la gestión de estas poblaciones. Así, es posible visibilizar los marcos institucionales en los que se reconoce un colectivo y se direccionan las demandas asociadas al vivir en condiciones de carencias, en un régimen responsable de tal estado de cosas.

  2. Exploración del modelo coronal MHD de Uchida

    Science.gov (United States)

    Francile, C.; Castro, J. I.; Flores, M.

    We present an analysis of the MHD model of an isothermal solar corona with radially symmetrical magnetic field and gravity. The solution in the approximation "WKB" was presented by Uchida (1968). The model is ex- plored for different coronal conditions and heights of initial perturbation to study the propagation of coronal waves and reproduce the observed char- acteristics of phenomena such as Moreton waves. Finally we discuss the obtained results. FULL TEXT IN SPANISH

  3. Are Spicules the Primary Source of Hot Coronal Plasma?

    Science.gov (United States)

    Klimchuk, James A.

    2011-01-01

    The recent discovery of Type II spicules has generated considerable excitement. It has even been suggested that these ejections can account for a majority of the hot plasma observed in the corona, thus obviating the need for "coronal" heating. If this is the case, however, then there should be observational consequences. We have begun to examine some of these consequences and find reason to question the idea that spicules are the primary source of hot coronal plasma.

  4. Observing the formation of flare-driven coronal rain

    OpenAIRE

    Scullion, E.; Rouppe van der Voort, L.; Antolin, P.; Wedemeyer, S.; Vissers, G.; E. P. Kontar; Gallagher, P

    2016-01-01

    PA. GV are funded by the European Research Council under the European Union Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement nr. 291058 Flare-driven coronal rain can manifest from rapidly cooled plasma condensations near coronal loop-tops in thermally unstable post-flare arcades. We detect 5 phases that characterise the post-flare decay:heating, evaporation, conductive cooling dominance for ~120 s, radiative/ enthalpy cooling dominance for ~4700 s and finally catastrophic ...

  5. Coronal Dynamics at Recent Total Solar Eclipses

    Science.gov (United States)

    Pasachoff, J. M.; Lu, M.; Davis, A. B.; Demianski, M.; Rusin, V.; Saniga, M.; Seaton, D. B.; Lucas, R.; Babcock, B. A.; Dantowitz, R.; Gaintatzis, P.; Seeger, C. H.; Malamut, C.; Steele, A.

    2014-12-01

    Our composite images of the solar corona based on extensive imaging at the total solar eclipses of 2010 (Easter Island), 2012 (Australia), and 2013 (Gabon) reveal several coronal mass ejections and other changes in coronal streamers and in polar plumes. Our resultant spatial resolution is finer than that available in imaging from spacecraft, including that from SOHO/LASCO or STEREO. We trace the eruptions back to their footpoints on the sun using imaging from SDO and SWAP, and follow them upwards through the corona, measuring velocities. The high-resolution computer compositing by Miloslav Druckmüller and Hana Druckmüllerová (2010 and 2013) and Pavlos Gaintatzis (2012) allows comparison of our images with those taken at intervals of minutes or hours along the totality path. Williams College's 2013 eclipse expedition was supported in part by grant 9327-13 from National Geographic Society/Committee for Research and Exploration. Our work on the 2012 eclipse is supported in part by grant AGS-1047726 from Solar Terrestrial Research/NSF AGS. V.R. and M.S. were partially supported by the VEGA grant agency project 2/0098/10 and 2/0003/13 (Slovak Academy of Sciences) and Grant 0139-12 from NG/CRE, and Hana Druckmüllerová by grant 205/09/1469 of the Czech Science Foundation. M.L. was supported by Sigma Xi. C.M. was a Keck Northeast Astronomy Consortium Summer Fellow, supported at Williams College by REU/NSF grant AST-1005024. Partial support was provided by U.S. Department of Defense's ASSURE program. J.M.P. thanks Caltech's Planetary Sciences Department for hospitality. Support for D.B.S. and SWAP came from PRODEX grant C90345 managed by ESA in collaboration with the Belgian Federal Science Policy Office (BELSPO) in support of the PROBA2/SWAP mission, and from the EC's Seventh Framework Programme (FP7/2007-2013) under grant 218816 (SOTERIA project, www.soteria-space.eu). SWAP is a project of the Centre Spatial de Liège and the Royal Observatory of Belgium funded by

  6. Evolving Coronal Holes and Interplanetary Erupting Stream Disturbances

    Indian Academy of Sciences (India)

    Rajendra Shelke

    2006-06-01

    Coronal holes and interplanetary disturbances are important aspects of the physics of the Sun and heliosphere. Interplanetary disturbances are identified as an increase in the density turbulence compared with the ambient solar wind. Erupting stream disturbances are transient large-scale structures of enhanced density turbulence in the interplanetary medium driven by the high-speed flows of low-density plasma trailing behind for several days. Here, an attempt has been made to investigate the solar cause of erupting stream disturbances, mapped by Hewish & Bravo (1986) from interplanetary scintillation (IPS) measurements made between August 1978 and August 1979 at 81.5 MHz. The position of the sources of 68 erupting stream disturbances on the solar disk has been compared with the locations of newborn coronal holes and/or the areas that have been coronal holes previously. It is found that the occurrence of erupting stream disturbances is linked to the emergence of newcoronal holes at the eruption site on the solar disk. A coronal hole is indicative of a radial magnetic field of a predominant magnetic polarity. The newborn coronal hole emerges on the Sun, owing to the changes in magnetic field configuration leading to the opening of closed magnetic structure into the corona. The fundamental activity for the onset of an erupting stream seems to be a transient opening of pre-existing closed magnetic structures into a new coronal hole, which can support high-speed flow trailing behind the compression zone of the erupting stream for several days.

  7. Transverse oscillations in a coronal loop triggered by a jet

    CERN Document Server

    Sarkar, S; Srivastava, A K; Banerjee, D

    2016-01-01

    We detect and analyse transverse oscillations in a coronal loop, lying at the south east limb of the Sun as seen from the \\textit{{Atmospheric Imaging Assembly}} (AIA) onboard \\textit{{Solar Dynamics Observatory}} (SDO). The jet is believed to trigger transverse oscillations in the coronal loop. The jet originates from a region close to the coronal loop on 19$^{\\rm th}$ September 2014 at 02:01:35 UT. The length of the loop is estimated to be between 377-539~Mm. Only one complete oscillation is detected with an average period of about $32\\pm5$~min. Using MHD seismologic inversion techniques, we estimate the magnetic field inside the coronal loop to be between $2.68 -4.5$~G. The velocity of the hot and cool components of the jet is estimated to be 168~km~s$^{-1}$ and 43~km~s$^{-1}$, respectively. The energy density of the jet is found to be greater than the energy density of the oscillating coronal loop. Therefore, we conclude that the jet {triggered} transverse oscillations in the coronal loop. To our knowledg...

  8. The Contribution of Coronal Jets To The Solar Wind

    CERN Document Server

    Lionello, R; Titov, V S; Leake, J E; MikiĆ, Z; Linker, J A; Linton, M G

    2016-01-01

    Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy content of the corona and solar wind, but the extent of these contributions remains uncertain. We have recently modeled the formation and evolution of coronal jets using a three-dimensional (3D) magnetohydrodynamic (MHD) code with thermodynamics in a large spherical domain that includes the solar wind. Our model is coupled to 3D MHD flux-emergence simulations, i.e, we use boundary conditions provided by such simulations to drive a time-dependent coronal evolution. The model includes parametric coronal heating, radiative losses, and thermal conduction, which enables us to simulate the dynamics and plasma properties of coronal jets in a more realistic manner than done so far. Here we employ these simulations to calculate the amount of mass and energy transported by coronal j...

  9. Los estudios de representaciones en las Ciencias Sociales en México: 1994-2007

    Directory of Open Access Journals (Sweden)

    Ana V. Palacios Gámaz

    2009-01-01

    Full Text Available El objetivo de este artículo consiste en investigar el estado del conocimiento que guardan los estudios sobre representaciones en el área de las Ciencias Sociales en México, en particular, la producción intelectual publicada en el Índice de Revistas Mexicanas de Investigación Científica y Tecnológica de México del Consejo Nacional de Ciencia y Tecnología, en el período de 1994 al 2007. En el estudio destaca la baja producción intelectual publicada sobre el tema de las representaciones en las Ciencias Sociales en los últimos trece años. Asimismo, sobresalen las investigaciones realizadas con enfoques sociológicos e históricos, el abordaje preferentemente de temas de género y educación; el predominio de ensayos sobre investigaciones empíricas, así como la elección primordialmente de la teoría de las representaciones sociales, desarrollada por Moscovici, para abordar el estudio de las representaciones.

  10. Why are halo coronal mass ejections faster?

    Institute of Scientific and Technical Information of China (English)

    Qing-Min Zhang; Yang Guo; Peng-Fei Chen; Ming-De Ding; Cheng Fang

    2010-01-01

    Halo coronal mass ejections(CMEs)have been to be significantly faster than normal CMEs,which is a long-standing puzzle.In order to solve the puzzle,we first investigate the observed properties of 31 limb CMEs that clearly display loopshaped frontal loops.The observational results show a strong tendency that slower CMEs are weaker in white-light intensity.Then,we perform a Monte Carlo simulation of 20000 artificial limb CMEs that have an average velocity of~523 km s-1.The Thomson scattering of these events is calculated when they are assumed to be observed as limb and halo events,respectively.It is found that the white-light intensity of many slow CMEs becomes remarkably reduced when they turn from being viewed as a limb event to being viewed as a halo event.When the intensity is below the background solar wind fluctuation,it is assumed that they would be missed by coronagraphs.The average velocity of"detectable"halo CMEs is~922 km s-1,very close to the observed value.This also indicates that wider events are more likely to be recorded.The results soundly suggest that the higher average velocity of halo CMEs is due to that a majority of slow events and some of narrow fast events carrying less material are so faint that they are blended with the solar wind fluctuations,and therefore are not observed.

  11. Active Longitude and Coronal Mass Ejection Occurrences

    Science.gov (United States)

    Gyenge, N.; Singh, T.; Kiss, T. S.; Srivastava, A. K.; Erdélyi, R.

    2017-03-01

    The spatial inhomogeneity of the distribution of coronal mass ejection (CME) occurrences in the solar atmosphere could provide a tool to estimate the longitudinal position of the most probable CME-capable active regions in the Sun. The anomaly in the longitudinal distribution of active regions themselves is often referred to as active longitude (AL). In order to reveal the connection between the AL and CME spatial occurrences, here we investigate the morphological properties of active regions. The first morphological property studied is the separateness parameter, which is able to characterize the probability of the occurrence of an energetic event, such as a solar flare or CME. The second morphological property is the sunspot tilt angle. The tilt angle of sunspot groups allows us to estimate the helicity of active regions. The increased helicity leads to a more complex buildup of the magnetic structure and also can cause CME eruption. We found that the most complex active regions appear near the AL and that the AL itself is associated with the most tilted active regions. Therefore, the number of CME occurrences is higher within the AL. The origin of the fast CMEs is also found to be associated with this region. We concluded that the source of the most probably CME-capable active regions is at the AL. By applying this method, we can potentially forecast a flare and/or CME source several Carrington rotations in advance. This finding also provides new information for solar dynamo modeling.

  12. Multiscale Modeling of Solar Coronal Magnetic Reconnection

    Science.gov (United States)

    Antiochos, Spiro K.; Karpen, Judith T.; DeVore, C. Richard

    2010-01-01

    Magnetic reconnection is widely believed to be the primary process by which the magnetic field releases energy to plasma in the Sun's corona. For example, in the breakout model for the initiation of coronal mass ejections/eruptive flares, reconnection is responsible for the catastrophic destabilizing of magnetic force balance in the corona, leading to explosive energy release. A critical requirement for the reconnection is that it have a "switch-on' nature in that the reconnection stays off until a large store of magnetic free energy has built up, and then it turn on abruptly and stay on until most of this free energy has been released. We discuss the implications of this requirement for reconnection in the context of the breakout model for CMEs/flares. We argue that it imposes stringent constraints on the properties of the flux breaking mechanism, which is expected to operate in the corona on kinetic scales. We present numerical simulations demonstrating how the reconnection and the eruption depend on the effective resistivity, i.e., the effective Lundquist number, and propose a model for incorporating kinetic flux-breaking mechanisms into MHO calculation of CMEs/flares.

  13. Geometric Model of a Coronal Cavity

    Science.gov (United States)

    Kucera, Therese A.; Gibson, S. E.; Ratawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Reeves, K. K.; Schmidt, D. J.; Sterling, A. C.; Tripathi, D. K.; Williams, D. R.; Zhang, M.

    2010-01-01

    We observed a coronal cavity from August 8-18 2007 during a multi-instrument observing campaign organized under the auspices of the International Heliophysical Year (IHY). Here we present initial efforts to model the cavity with a geometrical streamer-cavity model. The model is based the white-light streamer mode] of Gibson et a]. (2003 ), which has been enhanced by the addition of a cavity and the capability to model EUV and X-ray emission. The cavity is modeled with an elliptical cross-section and Gaussian fall-off in length and width inside the streamer. Density and temperature can be varied in the streamer and cavity and constrained via comparison with data. Although this model is purely morphological, it allows for three-dimensional, multi-temperature analysis and characterization of the data, which can then provide constraints for future physical modeling. Initial comparisons to STEREO/EUVI images of the cavity and streamer show that the model can provide a good fit to the data. This work is part of the effort of the International Space Science Institute International Team on Prominence Cavities

  14. Coronal activity from the ASAS eclipsing binaries

    CERN Document Server

    Szczygiel, D M; Paczynski, B; Pojmanski, G; Pilecki, B

    2008-01-01

    We combine the catalogue of eclipsing binaries from the All Sky Automated Survey (ASAS) with the ROSAT All Sky Survey (RASS). The combination results in 836 eclipsing binaries that display coronal activity and is the largest sample of active binary stars assembled to date. By using the (V-I) colors of the ASAS eclipsing binary catalogue, we are able to determine the distances and thus bolometric luminosities for the majority of eclipsing binaries that display significant stellar activity. A typical value for the ratio of soft X-ray to bolometric luminosity is L_X/L_bol ~ a few x 10^-4, similar to the ratio of soft X-ray to bolometric flux F_X/F_bol in the most active regions of the Sun. Unlike rapidly rotating isolated late-type dwarfs -- stars with significant outer convection zones -- a tight correlation between Rossby number and activity of eclipsing binaries is absent. We find evidence for the saturation effect and marginal evidence for the so-called "super-saturation" phenomena. Our work shows that wide-...

  15. Surface Flux Emergence and Coronal Eruption

    Science.gov (United States)

    Fang, Fang

    2016-05-01

    Among various active regions, delta-sunspots of aggregated spots of opposite polarities, are of particular interest due to their high productivity in energetic and recurrent eruptive events, such as X-class flares and homologous eruptions. We here study the formation of such complex magnetic structures by numerical simulations of magnetic flux emergence from the convection zone into the corona in an active-region scale domain. In our simulation, two pairs of bipolar sunspots form on the surface, originating from two buoyant segments of a single subsurface twisted flux rope. Expansion and rotation of the emerging fields in the two bipoles drive the two opposite polarities into each other with apparent rotating motion, producing a compact delta-sunspot with a sharp polarity inversion line (PIL). The formation of the delta-sunspot in such a realistic-scale domain produces emerging patterns similar to those formed in observations, e.g. the inverted polarity against Hale’s law, the curvilinear motion of the spot, strong transverse field with highly sheared magnetic and velocity fields at the PIL. Strong current builds up at the PIL, giving rise to reconnection, which produces a complex coronal magnetic connectivity with non-potential fields in the delta-spot overlaid by more relaxed fields connecting the two polarities at the two ends.

  16. Stellar Differential Rotation and Coronal Timescales

    CERN Document Server

    Gibb, G P S; Mackay, D H

    2014-01-01

    We investigate the timescales of evolution of stellar coronae in response to surface differential rotation and diffusion. To quantify this we study both the formation time and lifetime of a magnetic flux rope in a decaying bipolar active region. We apply a magnetic flux transport model to prescribe the evolution of the stellar photospheric field, and use this to drive the evolution of the coronal magnetic field via a magnetofrictional technique. Increasing the differential rotation (i.e. decreasing the equator-pole lap time) decreases the flux rope formation time. We find that the formation time is dependent upon the geometric mean of the lap time and the surface diffusion timescale. In contrast, the lifetime of flux ropes are proportional to the lap time. With this, flux ropes on stars with a differential rotation of more than eight times the solar value have a lifetime of less than two days. As a consequence, we propose that features such as solar-like quiescent prominences may not be easily observable on s...

  17. Potential Method of Predicting Coronal Mass Ejection

    Science.gov (United States)

    Imholt, Timothy

    2001-10-01

    Coronal Mass Ejections (CME) may be described as a blast of gas and highly charged solar mass fragments ejected into space. These ejections, when directed toward Earth, have many different effects on terrestrial systems ranging from the Aurora Borealis to changes in wireless communication. The early prediction of these solar events cannot be overlooked. There are several models currently accepted and utilized to predict these events, however, with earlier prediction of both the event and the location on the sun where the event occurs allows us to have earlier warnings as to when they will affect man-made systems. A better prediction could perhaps be achieved by utilizing low angular resolution radio telescope arrays to catalog data from the sun at different radio frequencies on a regular basis. Once this data is cataloged a better predictor for these CME’s could be found. We propose a model that allows a prediction to be made that appears to be longer than 24 hours.

  18. Are Coronal Loops Isothermal or Multithermal? Yes!

    CERN Document Server

    Schmelz, J T; Rightmire, L A; Kimble, J A; Del Zanna, G; Cirtain, J W; DeLuca, E E; Mason, H E

    2009-01-01

    Surprisingly few solar coronal loops have been observed simultaneously with TRACE and SOHO/CDS, and even fewer analyses of these loops have been conducted and published. The SOHO Joint Observing Program 146 was designed in part to provide the simultaneous observations required for in-depth temperature analysis of active region loops and determine whether these loops are isothermal or multithermal. The data analyzed in this paper were taken on 2003 January 17 of AR 10250. We used TRACE filter ratios, emission measure loci, and two methods of differential emission measure analysis to examine the temperature structure of three different loops. TRACE and CDS observations agree that Loop 1 is isothermal with Log T $=$ 5.85, both along the line of sight as well as along the length of the loop leg that is visible in the CDS field of view. Loop 2 is hotter than Loop 1. It is multithermal along the line of sight, with significant emission between 6.2 $<$ Log T $<$ 6.4, but the loop apex region is out of the CDS ...

  19. Anatomy of Depleted Interplanetary Coronal Mass Ejections

    Science.gov (United States)

    Kocher, M.; Lepri, S. T.; Landi, E.; Zhao, L.; Manchester, W. B., IV

    2017-01-01

    We report a subset of interplanetary coronal mass ejections (ICMEs) containing distinct periods of anomalous heavy-ion charge state composition and peculiar ion thermal properties measured by ACE/SWICS from 1998 to 2011. We label them “depleted ICMEs,” identified by the presence of intervals where C6+/C5+ and O7+/O6+ depart from the direct correlation expected after their freeze-in heights. These anomalous intervals within the depleted ICMEs are referred to as “Depletion Regions.” We find that a depleted ICME would be indistinguishable from all other ICMEs in the absence of the Depletion Region, which has the defining property of significantly low abundances of fully charged species of helium, carbon, oxygen, and nitrogen. Similar anomalies in the slow solar wind were discussed by Zhao et al. We explore two possibilities for the source of the Depletion Region associated with magnetic reconnection in the tail of a CME, using CME simulations of the evolution of two Earth-bound CMEs described by Manchester et al.

  20. Radio-quiet Fast Coronal Mass Ejections

    Science.gov (United States)

    Gopalswamy, N.; Aguilar-Rodriguez, E.; Kaiser, M. L.; Howard, R. A.

    2004-12-01

    Coronal mass ejections (CMEs) drive shocks in the interplanetary medium that produce type II radio emission. These CMEs are faster and wider on the average, than the general population of CMEs. However, when we start from fast (speed > 900 km/s) and wide (angular width > 60 degrees), more than half of them are not associated with radio bursts. In order to understand why these CMEs are radio quiet, we collected all the fast and wide (FW) CMEs detected by the Solar and Heliospheric Observatory (SOHO) mission's Large Angle and Spectrometric Coronagraph (LASCO) and isolated those without associated type II radio bursts. The radio bursts were identified in the dynamic spectra of the Radio and Plasma Wave (WAVES) Experiment on board the Wind spacecraft. We also checked the list against metric type II radio bursts reported in Solar Geophysical Data and isolated those without any radio emission. This exercise resulted in about 140 radio-quiet FW CMEs. We identified the source regions of these CMEs using the Solar Geophysical Data listings, cross-checked against the eruption regions in the SOHO/EIT movies. We explored a number of possibilities for the radio-quietness: (i) Source region being too far behind the limb, (ii) flare size, (iii) brightness of the CME, and (iv) the density of the ambient medium. We suggest that a combination of CME energy and the Alfven speed profile of the ambient medium is primarily responsible for the radio-quietness of these FW CMEs.

  1. Energy Release in Driven Twisted Coronal Loops

    Science.gov (United States)

    Bareford, M. R.; Gordovskyy, M.; Browning, P. K.; Hood, A. W.

    2016-01-01

    We investigate magnetic reconnection in twisted magnetic fluxtubes, representing coronal loops. The main goal is to establish the influence of the field geometry and various thermodynamic effects on the stability of twisted fluxtubes and on the size and distribution of heated regions. In particular, we aim to investigate to what extent the earlier idealised models, based on the initially cylindrically symmetric fluxtubes, are different from more realistic models, including the large-scale curvature, atmospheric stratification, thermal conduction and other effects. In addition, we compare the roles of Ohmic heating and shock heating in energy conversion during magnetic reconnection in twisted loops. The models with straight fluxtubes show similar distribution of heated plasma during the reconnection: it initially forms a helical shape, which subsequently becomes very fragmented. The heating in these models is rather uniformly distributed along fluxtubes. At the same time, the hot plasma regions in curved loops are asymmetric and concentrated close to the loop tops. Large-scale curvature has a destabilising influence: less twist is needed for instability. Footpoint convergence normally delays the instability slightly, although in some cases, converging fluxtubes can be less stable. Finally, introducing a stratified atmosphere gives rise to decaying wave propagation, which has a destabilising effect.

  2. A Catalog of Coronal "EIT Wave" Transients

    Science.gov (United States)

    Thompson, B. J.; Myers, D. C.

    2009-01-01

    Solar and Heliospheric Observatory (SOHO) Extreme ultraviolet Imaging Telescope (EIT) data have been visually searched for coronal "EIT wave" transients over the period beginning from 1997 March 24 and extending through 1998 June 24. The dates covered start at the beginning of regular high-cadence (more than one image every 20 minutes) observations, ending at the four-month interruption of SOHO observations in mid-1998. One hundred and seventy six events are included in this catalog. The observations range from "candidate" events, which were either weak or had insufficient data coverage, to events which were well defined and were clearly distinguishable in the data. Included in the catalog are times of the EIT images in which the events are observed, diagrams indicating the observed locations of the wave fronts and associated active regions, and the speeds of the wave fronts. The measured speeds of the wave fronts varied from less than 50 to over 700 km s(exp -1) with "typical" speeds of 200-400 km s(exp -1).

  3. SALUD MENTAL: UN ABORDAJE DESDE LA PERSPECTIVA ACTUAL DE LA PSICOLOGÍA DE LA SALUD

    Directory of Open Access Journals (Sweden)

    Moisés Mebarak

    2009-01-01

    Full Text Available Este artículo está basado en un estudio estado del arte acerca del entendimiento actual que se tiene sobre el concepto de salud mental, especialmente desde la perspectiva de la psicología de la salud. Con el fin de ilustrar este campo, se presentan algunos aportes y/o investigaciones tanto a nivel general como de la región costa Caribe colombiana. Se ha encontrado que el concepto de salud mental implica el desarrollo de estilos de vida y de características personales, interpersonales, sociales y laborales que apuntan a una idea integrada de bienestar biopsicosocial. De esta forma, la salud mental se entiende que sobrepasa y no es reducida a la simple ausencia de síntomas.

  4. un estudio comparativo

    Directory of Open Access Journals (Sweden)

    Federico Varona

    2007-01-01

    Full Text Available La comunicación efectiva es uno de los mayores retos que tienen hoy las organizaciones y empresas tanto a nivel nacional como internacional (global. Este artículo presenta los resultados de la investigación realizada por un equipo internacional de investigadores interesados en descubrir y comparar las conductas comunicativas o estilos de comunicación de los empleados finlandeses y mexicanos cuando interactúan con sus superiores. Para ello presentamos: primero, un breve marco teórico del estudio; segundo, la metodología; tercero, los resultados del análisis estadístico comparativo entre los empleados de Finlandia y México; cuarto, las conclusiones generales y su explicación cultural; y quinto, las implicaciones teóricas y prácticas de este estudio con respecto a las competencias comunicativas necesarias para la comunicación efectiva entre empleados y superiores tanto en organizaciones nacionales como internacionales (globales.

  5. Abordajes teóricos sobre las juventudes indígenas en Latinoamérica

    Directory of Open Access Journals (Sweden)

    Laura Kropff-Causa

    2017-01-01

    Full Text Available Una dificultad al proponer una sistematización de la información sobre juventud indígena en Latinoamérica tiene que ver con que las categorías “juventud” e “indígena” no emergen como datos directos de la realidad, sino que son construidas a partir de definiciones. Para contribuir al análisis de este entramado, esta investigación se focaliza en las definiciones con las que la academia latinoamericana ha contribuido en los últimos años. Finalmente, se propone el abordaje de edad y etnicidad como clivajes que definen la movilidad estructurada de subjetividades, identidades y agencias cuya trama debe leerse situada en cada contexto sociopolítico e histórico particular.

  6. Repensando la libertad de expresión desde el abordaje al art. 213 del Código Penal argentino

    Directory of Open Access Journals (Sweden)

    Matalone, Noelia

    2013-12-01

    Full Text Available Este ensayo intenta presentar abordajes críticos sobre el delito tipificado en el art. 213 del Código Penal. En tal temperamento, se contrapone el tipo penal de apología del delito con los derechos individuales de las personas, en particular, la libertad de expresión. En este sentido, la autora formula una propuesta de derogación de la norma, como consecuencia de los fundamentos y efectos de esta norma, todo ello en orden a preservar, por sobre los intereses que puedan sostener este tipo de prohibición, la pluralidad de voces en la sociedad. Para ello, apela al sentido de la tolerancia social y a los principios de razonalibidad y de necesidad del sistema penal al momento de investigar y perseguir este tipo de casos.

  7. Abdominoplastia multifuncional en ancla: nuestra experiencia y nueva sistemática de abordaje en el paciente sin adelgazamiento

    Directory of Open Access Journals (Sweden)

    J. Muñoz i Vidal

    Full Text Available La dermolipectomía multifuncional en ancla es una técnica efectiva en el tratamiento del contorno corporal en pacientes que han sufrido grandes pérdidas de peso. En la actualidad, en el sistema público de salud español, no es infrecuente que el cirujano plástico deba abordar pacientes en los que no ha habido adelgazamiento alguno y que más allá del contorno corporal, requieren una reparación de la pared abdominal. Los procedimientos reconstructivos de la pared abdominal no están reñidos con un abordaje simultáneo del contorno corporal para una mejora funcional y de la calidad de vida del paciente. Exponemos nuestra experiencia con este conocido patrón de dermolipectomía en 32 casos, en los que mostramos el abordaje hecho en 3 pacientes con ausencia o fracaso en el adelgazamiento. El gran volumen intrabdominal, graso y visceral, de estos pacientes sin adelgazamiento, conlleva que puedan presentar complicaciones por alteración en la relación continente-contenido abdominal tras grandes dermolipectomías; las más frecuentes son dehiscencia de sutura, necrosis de los colgajos, alteraciones respiratorias o cierre a tensión que en último término puede desencadenar un síndrome compartimental intrabdominal. La adaptación y fisioterapia respiratoria preoperatoria del enfermo, el diseño de colgajos suprapúbicos que eviten el cierre a tensión en el punto de unión de las suturas, el no despegamiento de los colgajos y la estimación de la presión intrabdominal intraoperatoria, permiten ampliar la indicación de este patrón de dermolipectomía a pacientes en los que no ha habido adelgazamiento.

  8. ON THE RELATIONSHIP BETWEEN THE CORONAL MAGNETIC DECAY INDEX AND CORONAL MASS EJECTION SPEED

    Energy Technology Data Exchange (ETDEWEB)

    Xu Yan; Liu Chang; Jing Ju; Wang Haimin, E-mail: yx2@njit.edu [Space Weather Research Lab, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, NJ 07102-1982 (United States)

    2012-12-10

    Numerical simulations suggest that kink and torus instabilities are two potential contributors to the initiation and prorogation of eruptive events. A magnetic parameter called the decay index (i.e., the coronal magnetic gradient of the overlying fields above the eruptive flux ropes) could play an important role in controlling the kinematics of eruptions. Previous studies have identified a threshold range of the decay index that distinguishes between eruptive and confined configurations. Here we advance the study by investigating if there is a clear correlation between the decay index and coronal mass ejection (CME) speed. Thirty-eight CMEs associated with filament eruptions and/or two-ribbon flares are selected using the H{alpha} data from the Global H{alpha} Network. The filaments and flare ribbons observed in H{alpha} associated with the CMEs help to locate the magnetic polarity inversion line, along which the decay index is calculated based on the potential field extrapolation using Michelson Doppler Imager magnetograms as boundary conditions. The speeds of CMEs are obtained from the LASCO C2 CME catalog available online. We find that the mean decay index increases with CME speed for those CMEs with a speed below 1000 km s{sup -1} and stays flat around 2.2 for the CMEs with higher speeds. In addition, we present a case study of a partial filament eruption, in which the decay indices show different values above the erupted/non-erupted part.

  9. Orbitotomía lateral mediante abordaje temporal Lateral orbitotomy using a temporal approach

    Directory of Open Access Journals (Sweden)

    H. Herencia Nieto

    2005-12-01

    Full Text Available La orbitotomía lateral sigue siendo en el momento actual la técnica quirúrgica de elección para la biopsia o extirpación de lesiones intraorbitarias laterales al nervio óptico, la biopsia del propio nervio óptico y la extirpación de la glándula lacrimal. Se han descrito múltiples incisiones cutáneas para llevar a cabo esta intervención; la más frecuentemente empleada por el momento es la incisión palpebral, que discurre a nivel de alguna arruga del párpado superior. Aunque los resultados obtenidos con esta incisión suelen ser aceptables, no está exenta de complicaciones, ni estéticas ni funcionales. Por esto, en los últimos años han ido apareciendo nuevas incisiones que intentan evitar estas complicaciones. Entre estas nuevas vías de abordaje a la pared lateral de la órbita se encuentra la incisión temporal. En los últimos 3 años, se ha intervenido en nuestro servicio a cuatro pacientes para llevar a cabo biopsia o extirpación de masas intraorbitarias mediante orbitotomía lateral, siempre a través de una incisión temporal. En todos los casos esta incisión permitió una amplia exposición del campo quirúrgico y la cómoda realización de la intervención, obteniéndose resultados estéticos y funcionales excelentes, y sin ninguna secuela ni complicación permanente. La complicación específica más frecuente de esta incisión es la paresia de la rama frontal del nervio facial. Una técnica de disección cuidadosa suele ser suficiente para evitarla. Todo esto hace que esta incisión, tal y como la describimos aquí, sea de elección para llevar a cabo la orbitotomía lateral, constituyendo en nuestro criterio una alternativa perfectamente válida y a tener en cuenta frente a las incisiones «clásicas», a las que llega a superar en muchos aspectos.The lateral orbitotomy it still the surgical technique of choice for biopsies or the removal of intraorbital lesions that are lateral to the optic nerve, for biopsies of

  10. Forecasting Coronal Mass Ejections from Vector Magnetograms

    Science.gov (United States)

    Falconer, D. A.; Moore, R. L.; Gary, G. A.; Six, N. Frank (Technical Monitor)

    2002-01-01

    In a 17 vector magnetogram study of 12 bipolar active regions (Falconer, Moore, & Gary, 2002, ApJ in press), we correlated four quantitative global magnetic measures with the Coronal Mass Ejections (CME) productivity of the active region. The global measures included a measure of active region size, the total magnetic flux phi and three measures of an active region global nonpotentiality 1) the net current (I (sub N)), 2) the length of the strong-shear, strong-field main neutral line (L(sub SS)) and 3) and the normalized twist (alpha = muIN/PHI). The CME productivity was determined from YOHKOH/SXT observations, Geostationary Operational Environmental Satellite (GOES), and when possible Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph Experiment (SOHO/LASCO) observations within 12 days of the day of the magnetogram. We found that the three measures of global nonpotentiality (I(sub N), L(sub SS), alpha) were all well correlated (greater than 99% confidence level) with an active region's CME productivity. The sample size was to small to confirm if there was a statistical significant correlation of the globally nonscientist measures with future CME activity (i.e. from the date of the magnetogram forward). We are doubling our sample, and will report on the statistical significance of global nonpotentiality as a predictor of future CME productivity. The new active regions are all from the first year of the upgraded MSFC vector magnetograms. This work, is funded by NSF through the Space Weather Program, by NASA through the Living with the Star, Targeted Research and Technology, and by NASA Solar Physics Supporting Research and Technology Program. The upgrade to the MSFC vector magnetograph was supported by the High Energy Solar Spectroscopic Imager (HESSI) mission.

  11. MAGNETIC FLUX SUPPLEMENT TO CORONAL BRIGHT POINTS

    Energy Technology Data Exchange (ETDEWEB)

    Mou, Chaozhou; Huang, Zhenghua; Xia, Lidong; Li, Bo; Fu, Hui; Jiao, Fangran; Hou, Zhenyong [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 Shandong (China); Madjarska, Maria S., E-mail: z.huang@sdu.edu.cn [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom)

    2016-02-10

    Coronal bright points (BPs) are associated with magnetic bipolar features (MBFs) and magnetic cancellation. Here we investigate how BP-associated MBFs form and how the consequent magnetic cancellation occurs. We analyze longitudinal magnetograms from the Helioseismic and Magnetic Imager to investigate the photospheric magnetic flux evolution of 70 BPs. From images taken in the 193 Å passband of the Atmospheric Imaging Assembly (AIA) we dermine that the BPs’ lifetimes vary from 2.7 to 58.8 hr. The formation of the BP MBFs is found to involve three processes, namely, emergence, convergence, and local coalescence of the magnetic fluxes. The formation of an MBF can involve more than one of these processes. Out of the 70 cases, flux emergence is the main process of an MBF buildup of 52 BPs, mainly convergence is seen in 28, and 14 cases are associated with local coalescence. For MBFs formed by bipolar emergence, the time difference between the flux emergence and the BP appearance in the AIA 193 Å passband varies from 0.1 to 3.2 hr with an average of 1.3 hr. While magnetic cancellation is found in all 70 BPs, it can occur in three different ways: (I) between an MBF and small weak magnetic features (in 33 BPs); (II) within an MBF with the two polarities moving toward each other from a large distance (34 BPs); (III) within an MBF whose two main polarities emerge in the same place simultaneously (3 BPs). While an MBF builds up the skeleton of a BP, we find that the magnetic activities responsible for the BP heating may involve small weak fields.

  12. Standing Kink modes in three-dimensional coronal loops

    Energy Technology Data Exchange (ETDEWEB)

    Pascoe, D. J.; De Moortel, I., E-mail: dpascoe@mcs.st-andrews.ac.uk [School of Mathematics and Statistics, University of St. Andrews, St. Andrews KY16 9SS (United Kingdom)

    2014-04-01

    So far, the straight flux tube model proposed by Edwin and Roberts is the most commonly used tool in practical coronal seismology, in particular, to infer values of the (coronal) magnetic field from observed, standing kink mode oscillations. In this paper, we compare the period predicted by this basic model with three-dimensional (3D) numerical simulations of standing kink mode oscillations, as the period is a crucial parameter in the seismological inversion to determine the magnetic field. We perform numerical simulations of standing kink modes in both straight and curved 3D coronal loops and consider excitation by internal and external drivers. The period of oscillation for the displacement of dense coronal loops is determined by the loop length and the kink speed, in agreement with the estimate based on analytical theory for straight flux tubes. For curved coronal loops embedded in a magnetic arcade and excited by an external driver, a secondary mode with a period determined by the loop length and external Alfvén speed is also present. When a low number of oscillations is considered, these two periods can result in a single, non-resolved (broad) peak in the power spectrum, particularly for low values of the density contrast for which the two periods will be relatively similar. In that case (and for this particular geometry), the presence of this additional mode would lead to ambiguous seismological estimates of the magnetic field strength.

  13. Standing Slow MHD Waves in Radiatively Cooling Coronal Loops

    Indian Academy of Sciences (India)

    K. S. Al-Ghafri

    2015-06-01

    The standing slow magneto-acoustic oscillations in cooling coronal loops are investigated. There are two damping mechanisms which are considered to generate the standing acoustic modes in coronal magnetic loops, namely, thermal conduction and radiation. The background temperature is assumed to change temporally due to optically thin radiation. In particular, the background plasma is assumed to be radiatively cooling. The effects of cooling on longitudinal slow MHD modes is analytically evaluated by choosing a simple form of radiative function, that ensures the temperature evolution of the background plasma due to radiation, coincides with the observed cooling profile of coronal loops. The assumption of low-beta plasma leads to neglecting the magnetic field perturbation and, eventually, reduces the MHD equations to a 1D system modelling longitudinal MHD oscillations in a cooling coronal loop. The cooling is assumed to occur on a characteristic time scale, much larger than the oscillation period that subsequently enables using the WKB theory to study the properties of standing wave. The governing equation describing the time-dependent amplitude of waves is obtained and solved analytically. The analytically derived solutions are numerically evaluated to give further insight into the evolution of the standing acoustic waves. We find that the plasma cooling gives rise to a decrease in the amplitude of oscillations. In spite of the reduction in damping rate caused by rising the cooling, the damping scenario of slow standing MHD waves strongly increases in hot coronal loops.

  14. Discurso, performatividad y emergencia del sujeto: Un abordaje desde el post-estructuralismo

    Directory of Open Access Journals (Sweden)

    María Virginia Morales

    2014-02-01

    Full Text Available El estudio de las estructuras de significación y la conformación de hegemonías desempeñan un papel protagónico para las teorías post-estructuralistas de la política. En el presente escrito abordo una serie de aspectos ontológicos de dichas teorías a partir de la reflexión de las condiciones de emergencia de los sistemas de significación, el modo en que estos sistemas son construidos y la manera en que los mismos constituyen al campo de lo social y a los sujetos que se posicionan en él. De este modo, me motiva el objetivo de analizar unos de los principales presupuestos epistemológicos de categorías que considero centrales para cualquier investigación post-estructuralista, a saber: discurso, performatividad y sujeto. En pocas palabras, el presente escrito tiene la doble finalidad de indagar en aspectos ontológicos que fundan a las teorías en cuestión, a la vez que comenzar a desarrollar un marco conceptual desde el cual abordar las condiciones de emergencia de las estructuras discursivas que conforman y dan sentido a los sujetos y a lo social.

  15. Estudio de competencias del teleformador

    OpenAIRE

    Marcelo, Carlos

    2005-01-01

    El Servicio Andaluz de Empleo de la Consejeria de Empleo de la Junta de Andalucia ha realizado un Estudio de Competencias del Teleformador. Este estudio establece un análisis de competencias necesarias para el diseño, desarrollo y gestión de acciones de e-Learning.

  16. Characteristics of EUV coronal jets observed with STEREO/SECCHI

    CERN Document Server

    Nistico, G; Patsourakos, S; Zimbardo, G

    2009-01-01

    In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008. The appearances of the coronal jets were always correlated with underlying small-scale chromospheric bright points. A basic characterisation of the morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evolution. A classification of the events with respect to previous jet studies shows that amongst the 79 events there were 37 Eiffel tower-type jet events commonly interpreted as a small-scale (about 35 arcsec) magnetic bipole reconnecting with the ambient unipolar open coronal magnetic fields at its looptops, and 12 lambda-type jet events commonly interpreted as reconnection with the amb...

  17. Transverse, Propagating Velocity Perturbations in Solar Coronal Loops

    CERN Document Server

    De Moortel, I; Wright, A N; Hood, A W

    2015-01-01

    This short review paper gives an overview of recently observed transverse, propagating velocity perturbations in coronal loops. These ubiquitous perturbations are observed to undergo strong damping as they propagate. Using 3D numerical simulations of footpoint-driven transverse waves propagating in a coronal plasma with a cylindrical density structure, in combination with analytical modelling, it is demonstrated that the observed velocity perturbations can be understood in terms of coupling of different wave modes in the inhomogeneous boundaries of the loops. Mode coupling in the inhomogeneous boundary layers of the loops leads to the coupling of the transversal (kink) mode to the azimuthal (Alfven) mode, observed as the decay of the transverse kink oscillations. Both the numerical and analytical results show the spatial profile of the damped wave has a Gaussian shape to begin with, before switching to exponential decay at large heights. In addition, recent analysis of CoMP (Coronal Multi-channel Polarimeter)...

  18. Flux Rope Formation Preceding Coronal Mass Ejection Onset

    CERN Document Server

    Green, L M

    2009-01-01

    We analyse the evolution of a sigmoidal (S shaped) active region toward eruption, which includes a coronal mass ejection (CME) but leaves part of the filament in place. The X-ray sigmoid is found to trace out three different magnetic topologies in succession: a highly sheared arcade of coronal loops in its long-lived phase, a bald-patch separatrix surface (BPSS) in the hours before the CME, and the first flare loops in its major transient intensity enhancement. The coronal evolution is driven by photospheric changes which involve the convergence and cancellation of flux elements under the sigmoid and filament. The data yield unambiguous evidence for the existence of a BPSS, and hence a flux rope, in the corona prior to the onset of the CME.

  19. Polarisation of microwave emission from reconnecting twisted coronal loops

    CERN Document Server

    Gordovskyy, Mykola; Kontar, Eduard

    2016-01-01

    Magnetic reconnection and particle acceleration due to the kink instability in twisted coronal loops can be a viable scenario for confined solar flares. Detailed investigation of this phenomenon requires reliable methods for observational detection of magnetic twist in solar flares, which may not be possible solely through extreme UV and soft X-ray thermal emission. The gradient of microwave polarisation across flaring loops can serve as one of the detection criteria. The aim of this study is to investigate the effect of magnetic twist in flaring coronal loops on the polarisation of gyro-synchrotron microwave emission, and determine whether microwave emission polarisation could provide a means for observational detection. We use time-dependent magnetohydrodynamic and test-particle models, developed using LARE3D and GCA codes to investigate twisted coronal loops relaxing following the kink-instability, and calculate synthetic microwave emission maps (I and V Stokes components) using GX simulator. It is found t...

  20. A data driven kinetic approach to coronal heating

    CERN Document Server

    Toutountzi, A; Isliker, H; Moraitis, K; Georgoulis, M; Chintzoglou, G

    2016-01-01

    Coronal heating through the explosive release of magnetic energy remains an open problem in solar physics. Several one-dimensional hydrodynamical models have been developed over the last decade, using simple approaches for the way energy is deposited and transported in the coronal plasma, namely by inserting 'nanoflares' in the form of 'hot spots' at random sites and times. Our aim in this work is to investigate the problem from a different perspective. With the help of a nonlinear force-free extrapolation method we reconstruct the coronal magnetic field of a well-studied solar active region using an observed photospheric vector magnetogram of the region as the required boundary condition. We then determine the locations, energy contents, and volumes of unstable areas within the active-region corona. These areas include strong gradients in the magnetic field and are naturally connected to three-dimensional current sheets. The statistical distributions of these volumes, their fractal structure and correspondin...

  1. Coronal Loop Evolution Observed with AIA and Hi-C

    Science.gov (United States)

    Mulu-Moore, Fana; Winebarger, A.; Cirtain, J.; Kobayashi, K.; Korreck, K.; Golub, L.; Kuzin. S.; Walsh, R.; DeForest, C.; DePontieu, B.; Weber, M.

    2012-01-01

    Despite much progress toward understanding the dynamics of the solar corona, the physical properties of coronal loops are not yet fully understood. Recent investigations and observations from different instruments have yielded contradictory results about the true physical properties of coronal loops. In the past, the evolution of loops has been used to infer the loop substructure. With the recent launch of High Resolution Coronal Imager (Hi-C), this inference can be validated. In this poster we discuss the first results of loop analysis comparing AIA and Hi-C data. We find signatures of cooling in a pixel selected along a loop structure in the AIA multi-filter observations. However, unlike previous studies, we find that the cooling time is much longer than the draining time. This is inconsistent with previous cooling models.

  2. Influence of coronal holes on CMEs in causing SEP events

    Institute of Scientific and Technical Information of China (English)

    Cheng-Long Shen; Jia Yao; Yu-Ming Wang; Pin-Zhong Ye; Xue-Pu Zhao; Shui Wang

    2010-01-01

    The issue of the influence of coronal holes(CHs)on coronal mass ejections(CMEs)in causing solar energetic particle(SEP)events is revisited.It is a continuation and extension of our previous work,in which no evident effects of CHs on CMEs in generating SEPs were found by statistically investigating 56 CME events.This result is consistent with the conclusion obtained by Kahler in 2004.We extrapolate the coronal magnetic field,define CHs as the regions consisting of only open magnetic field lines and perform a similar analysis on this issue for 76 events in total by extending the study interval to the end of 2008.Three key parameters,CH proximity,CH area and CH relative position,are involved in the analysis.The new result confirms the previous conclusion that CHs did not show any evident effect on CMEs in causing SEP events.

  3. Ultraviolet Spectroscopic Observations of Coronal Streamers in the SOHO Era

    Indian Academy of Sciences (India)

    Leonard Strachan

    2008-03-01

    Measurements made with the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory can be used to determine physical parameters in the solar corona such as hydrogen and ion kinetic temperatures, electron densities, and absolute elemental abundances. Hydrogen and ion outflow velocities can be determined by combining the UV spectroscopic measurements with white light polarized brightness measurements. These combined measurements can be used to reveal physical characteristics of coronal streamers. To date we have studied plasma properties, such as the variation of plasma outflows in quiescent streamers, primarily in classic helmet streamers at solar minimum. Outflows have not been observed in the centers of coronal streamers suggesting that these are closed magnetic field regions.We propose to study all of the coronal streamers in the UVCS synoptic dataset in order to investigate different types of streamers and their long-term evolution.

  4. Characterizing the Properties of Coronal Magnetic Null Points

    Science.gov (United States)

    Barnes, Graham; DeRosa, Marc; Wagner, Eric

    2015-08-01

    The topology of the coronal magnetic field plays a role in a wide range of phenomena, from Coronal Mass Ejections (CMEs) through heating of the corona. One fundamental topological feature is the null point, where the magnetic field vanishes. These points are natural sites of magnetic reconnection, and hence the release of energy stored in the magnetic field. We present preliminary results of a study using data from the Helioseismic and Magnetic Imager aboard NASA's Solar Dynamics Observatory to characterize the properties and evolution of null points in a Potential Field Source Surface model of the coronal field. The main properties considered are the lifetime of the null points, their distribution with height, and how they form and subsequently vanish.This work is supported by NASA/LWS Grant NNX14AD45G, and by NSF/SHINE grant 1357018.

  5. Determination of coronal temperatures from electron density profiles

    CERN Document Server

    Lemaire, J F

    2011-01-01

    The most popular method for determining coronal temperatures is the scale-height-method (shm). It is based on electron density profiles inferred from White Light (WL) brightness measurements of the corona during solar eclipses. This method has been applied to several published coronal electron density models. The calculated temperature distributions reach a maximum at r > 1.3 RS, and therefore do not satisfy one of the conditions for applying the shm method. Another method is the hydrostatic equilibrium method (hst), which enables coronal temperature distributions to be determined, providing solutions to the hydrostatic equilibrium equation. The temperature maximas using the hst method are almost equal to those obtained using the shm method, but the temperature peak is always at significantly lower altitude when the hst-method is used than when the shm-method is used. A third and more recently developed method, dyn, can be used for the same published electron density profiles. The temperature distributions ob...

  6. The Nature of CME-Flare Associated Coronal Dimming

    CERN Document Server

    Cheng, J X

    2016-01-01

    Coronal mass ejections (CMEs) are often accompanied by coronal dimming evident in extreme ultraviolet (EUV) and soft X-ray observations. The locations of dimming are sometimes considered to map footpoints of the erupting flux rope. As the emitting material expands in the corona, the decreased plasma density leads to reduced emission observed in spectral and irradiance measurements. Therefore, signatures of dimming may reflect properties of CMEs in the early phase of its eruption. In this study, we analyze the event of flare, CME, and coronal dimming on December 26, 2011. We use the data from the Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatories (SDO) for disk observations of the dimming, and analyze images taken by EUVI, COR1, and COR2 onboard the Solar Terrestrial Relations Observatories to obtain the height and velocity of the associated CMEs observed at the limb. We also measure magnetic reconnection rate from flare observations. Dimming occurs in a few locations next to the flare ribbons,...

  7. Examining the Properties of Jets in Coronal Holes

    Science.gov (United States)

    Gaulle, Owen; Adams, Mitzi L.; Tennant, A. F.

    2012-01-01

    We examined both X-ray and Magnetic field data in order to determine if there is a correlation between emerging magnetic flux and the production of Coronal jets. It was proposed that emerging flux can be a trigger to a coronal jet. The jet is thought to be caused when local bipoles reconnect or when a region of magnetic polarity emerges through a uniform field. In total we studied 15 different jets that occurred over a two day period starting 2011-02-27 00:00:00 UTC and ending 2011-02-28 23:59:55 UTC. All of the jets were contained within a coronal hole that was centered on the disk. Of the 15 that we studied 6 were shown to have an increase of magnetic flux within one hour prior to the creation of the jet and 10 were within 3 hours before the event.

  8. Damping of Slow Magnetoacoustic Waves in an Inhomogeneous Coronal Plasma

    Indian Academy of Sciences (India)

    Nagendra Kumar; Pradeep Kumar; Shiv Singh; Anil Kumar

    2008-03-01

    We study the propagation and dissipation of slow magnetoacoustic waves in an inhomogeneous viscous coronal loop plasma permeated by uniform magnetic field. Only viscosity and thermal conductivity are taken into account as dissipative processes in the coronal loop. The damping length of slow-mode waves exhibit varying behaviour depending upon the physical parameters of the loop in an active region AR8270 observed by TRACE. The wave energy flux associated with slow magnetoacoustic waves turns out to be of the order of 106 erg cm-2 s-1 which is high enough to replace the energy lost through optically thin coronal emission and the thermal conduction belowto the transition region. It is also found that only those slow-mode waves which have periods more than 240 s provide the required heating rate to balance the energy losses in the solar corona. Our calculated wave periods for slow-mode waves nearly match with the oscillation periods of loop observed by TRACE.

  9. The Search for Stellar Coronal Mass Ejections

    Science.gov (United States)

    Villadsen, Jacqueline; Hallinan, Gregg; Monroe, Ryan; Bourke, Stephen; Starburst Program Team

    2017-01-01

    Coronal mass ejections (CMEs) may dramatically impact habitability and atmospheric composition of planets around magnetically active stars, including young solar analogs and many M dwarfs. Theoretical predictions of such effects are limited by the lack of observations of stellar CMEs. My thesis addresses this gap through a search for the spectral and spatial radio signatures of CMEs on active M dwarfs.Solar CMEs produce radio bursts with a distinctive spectral signature, narrow-band plasma emission that drifts to lower frequency as a CME expands outward. To search for analogous events on nearby stars, I worked on system design, software, and commissioning for the Starburst project, a wideband single-baseline radio interferometry backend dedicated to stellar observations. In addition, I led a survey of nearby active M dwarfs with the Karl G. Jansky Very Large Array (JVLA), detecting 12 bright (>10 mJy) radio bursts in 58 hours. This survey’s ultra-wide bandwidth (0.23-6.0 GHz) dynamic spectroscopy, unprecedented for stellar observations, revealed diverse behavior in the time-frequency plane. Flare star UV Ceti produced complex, luminous events reminiscent of brown dwarf aurorae; AD Leo sustained long-duration, intense, narrow-band "storms"; and YZ CMi emitted a burst with substructure with rapid frequency drift, resembling solar Type III bursts, which are attributed to electrons moving at speeds of order 10% of the speed of light.To search for the spatial signature of CMEs, I led 8.5-GHz observations with the Very Long Baseline Array simultaneous to 24 hours of the JVLA survey. This program detected non-thermal continuum emission from the stars in all epochs, as well as continuum flares on AD Leo and coherent bursts on UV Ceti, enabling measurement of the spatial offset between flaring and quiescent emission.These observations demonstrate the diversity of stellar transients that can be expected in time-domain radio surveys, especially with the advent of large low

  10. Kinematics and amplitude evolution of global coronal extreme ultraviolet waves

    Institute of Scientific and Technical Information of China (English)

    Ting Li; Jun Zhang; Shu-Hong Yang; Wei Liu

    2012-01-01

    With the observations of the Solar-Terrestrial Relations Observatory (STEREO) and the Solar Dynamics Observatory (SDO),we analyze in detail the kinematics of global coronal waves together with their intensity amplitudes (so-called "perturbation profiles").We use a semi-automatic method to investigate the perturbation profiles of coronal waves.The location and amplitude of the coronal waves are calculated over a 30° sector on the sphere,where the wave signal is strongest.The position with the strongest perturbation at each time is considered as the location of the wave front.In all four events,the wave velocities vary with time for most of their lifetime,up to 15 min,while in the event observed by the Atmospheric Imaging Assembly there is an additional early phase with a much higher velocity.The velocity varies greatly between different waves from 216 to 440 km s-1.The velocity of the two waves initially increases,subsequently decreases,and then increases again.Two other waves show a deceleration followed by an acceleration.Three categories of amplitude evolution of global coronal waves are found for the four events.The first is that the amplitude only shows a decrease.The second is that the amplitude initially increases and then decreases,and the third is that the amplitude shows an orderly increase,a decrease,an increase again and then a decrease.All the extreme ultraviolet waves show a decrease in amplitude while propagating farther away,probably because the driver of the global coronal wave (coronal mass ejection) is moving farther away from the solar surface.

  11. SIMULATIONS OF SOLAR JETS CONFINED BY CORONAL LOOPS

    Energy Technology Data Exchange (ETDEWEB)

    Wyper, P. F. [Oak Ridge Associated Universities, Heliophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); DeVore, C. R., E-mail: peter.f.wyper@nasa.gov, E-mail: c.richard.devore@nasa.gov [Heliophysics Science Division, NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States)

    2016-03-20

    Coronal jets are collimated, dynamic events that occur over a broad range of spatial scales in the solar corona. In the open magnetic field of coronal holes, jets form quasi-radial spires that can extend far out into the heliosphere, while in closed-field regions the jet outflows are confined to the corona. We explore the application of the embedded-bipole model to jets occurring in closed coronal loops. In this model, magnetic free energy is injected slowly by footpoint motions that introduce twist within the closed dome of the jet source region, and is released rapidly by the onset of an ideal kink-like instability. Two length scales characterize the system: the width (N) of the jet source region and the footpoint separation (L) of the coronal loop that envelops the jet source. We find that both the conditions for initiation and the subsequent dynamics are highly sensitive to the ratio L/N. The longest-lasting and most energetic jets occur along long coronal loops with large L/N ratios, and share many of the features of open-field jets, while smaller L/N ratios produce shorter-duration, less energetic jets that are affected by reflections from the far-loop footpoint. We quantify the transition between these behaviors and show that our model replicates key qualitative and quantitative aspects of both quiet Sun and active-region loop jets. We also find that the reconnection between the closed dome and surrounding coronal loop is very extensive: the cumulative reconnected flux at least matches the total flux beneath the dome for small L/N, and is more than double that value for large L/N.

  12. Coronal seismology waves and oscillations in stellar coronae

    CERN Document Server

    Stepanov, Alexander; Nakariakov, Valery M

    2012-01-01

    This concise and systematic account of the current state of this new branch of astrophysics presents the theoretical foundations of plasma astrophysics, magneto-hydrodynamics and coronal magnetic structures, taking into account the full range of available observation techniques -- from radio to gamma. The book discusses stellar loops during flare energy releases, MHD waves and oscillations, plasma instabilities and heating and charged particle acceleration. Current trends and developments in MHD seismology of solar and stellar coronal plasma systems are also covered, while recent p

  13. Automatic measurement of orbital volume in unilateral coronal synostosis

    DEFF Research Database (Denmark)

    Dahl, Vedrana Andersen; Einarsson, Gudmundur; Darvann, Tron Andre;

    2016-01-01

    Premature fusion of the coronal suture on one side of the calvaria (unilateral coronal synostosis, UCS) results in asymmetric craniofacial development and the deformation of the orbits. Often this necessitates surgery, where CT scanning is employed to obtain measures of the bony orbit...... segmentations. We obtain similar measures, as well as high Dice scores, compared to the experts. The run time for the proposed approach with a prototype implementation is around 3 minutes on a standard laptop, making the method suitable for rapid evaluation of orbital volume in UCS....

  14. Abordaje multidisciplinario de la enfermedad humana por infiltración de sustancias modelantes

    Directory of Open Access Journals (Sweden)

    J. Gordillo-Hernández

    2013-09-01

    Full Text Available En la búsqueda por mejorar la apariencia del cuerpo y de la cara con fines estéticos o reconstructivos por alguna deformidad, han aparecido técnicas no quirúrgicas que consisten en inyectar diversas sustancias modelantes bajo la premisa de que son métodos sencillos, poco dolorosos, económicos y aparentemente seguros. La sociedad actual exige una mayor preocupación por los patrones estéticos, lo que ha motivado la práctica cada vez más frecuente de la aplicación de sustancias ilícitas con el fin de aumentar el volumen y modelar ciertas partes del cuerpo sin someterse a procedimientos quirúrgicos. La ignorancia que existe en algunos países como México y otros de Latinoamerica, ha propiciado que el número de pacientes que se somete a este tipo de tratamientos por personal no capacitado y en lugares no autorizados sea cada vez mayor, sin considerar el daño irreversible que causarán a su salud física, a su autoestima y finalmente a su calidad de vida futura. Los Servicios de Cirugía Plástica y Reumatología del Hospital General de México, han sido pioneros en el estudio integral y multidisciplinario de la enfermedad humana por modelantes, han ampliado el conocimiento de la historia natural de la enfermedad, de su tratamiento médico y quirúrgico, asi como de su pronóstico. El objetivo principal de este trabajo es concentrar toda esta información en un protocolo de manejo sistematizado, mediante búsqueda en el archivo del Servicio de Cirugia Plástica "Dr. Fernando Ortiz Monasterio" del Hospital General de Mexico. Esta búsqueda abarcó 35 pacientes de los cuales se obtuvieron resultados con datos durante el periodo 2006 a 2010, demostrando la importancia de diagnosticar a los pacientes, llevar un control estrecho, explicar paso a paso el proceso de su enfermedad, el tratamiento multidiciplinario, así como el pronóstico en cuanto a si es candidato a una reconstrucción o continuará con tratamiento médico.

  15. Panorama sobre los estudios de clima organizacional en Bogotá, Colombia(1994-2005

    Directory of Open Access Journals (Sweden)

    Diana Vega

    2006-01-01

    Full Text Available El interés por el estudio del clima organizacional ha crecido rápidamente durante los últimos años, ya que las organizaciones, a través de la implementación de sistemas gestión de calidad y la inclusión de dicho tema en los indicadores de gestión, la han asumido como uno de los elementos básicos para generar mejoramiento continuo. Así, el objetivo de este artículo es presentar el panorama de los estudios de clima organizacional(CO en Bogotá, D.C. (Colombia, hallados en 10 instituciones de educación superior y 2 bibliotecas públicas, de los años 1994 a 2005. Se revisaron 168 documentos, de los cuales se tomaron, como base para el presente artículo, 93 en psicología del trabajo y las organizaciones y áreas relacionadas con la gestión humana; de estos, a suvez, 67 son trabajos de grado (48 en pregrado y19 en postgrado, 11 artículos científicos y 15 libros. Esta revisión permitió identificar las diferentes definiciones, los autores más representativos citados en los trabajos consultados, los factores asociados al estudio del clima organizacional, los instrumentos utilizados para medirlo y el abordaje del tema que se hace desde diferentes disciplinas en el contexto objeto de estudio.

  16. Estudio de usabilidad del Portal de Periódicos de CAPES

    Directory of Open Access Journals (Sweden)

    Luciana Ferreira da Costa

    2011-08-01

    Full Text Available Objetivo. El estudio analiza la usabilidad del Portal de Periódicos de la Coordinación de Perfeccionamiento de Personal de Nivel Superior (CAPES en base a los parámetros de usabilidad desarrollados por el estudioso Jakob Nielsen y bajo la perspectiva de un estudio de usuario, haciendo una vinculación inevitable de la información con los ámbitos de la tecnología y la Ciencia de la Información. Método. Este es un estudio de naturaleza descriptiva, usa un abordaje cualitativo con aporte cuantitativo. Tiene como sujetos de investigación los docentes permanentes vinculados a los Programas de Postgrado del Centro de Ciencias de la Salud de la Universidad Federal de Paraíba. Los datos fueron recolectados por medio de investigación bibliográfica y documental, además de un cuestionario y entrevista. Para el análisis de datos, se utilizó el análisis descriptivo por categorías. Como resultados se evidenció la calidad de uso del Portal. Resultados. Corrobora que la mayoría de los atributos de usabilidad del Portal está calificada en niveles por encima de la media, con excepción del atributo Baja tasa de errores, que presentó media regular.Conclusiones. El presente estudio de usabilidad del Portal ha constituido un importante instrumento de evaluación institucional de uso de este sistema de información.

  17. y casos de estudios

    Directory of Open Access Journals (Sweden)

    Esteban Valenzuela Van Treek

    2006-01-01

    latinoamericanas, adentrándose en las problemáticas de la más relevantes, así como reflexionar sobre el presente de ellas, tomando para esto algunos casos de estudio.. “En el caso de las áreas metropolitanas, la concentración y el crecimiento de las grandes ciudades con fenómenos de nuevas barriadas, de municipios limítrofes y de ciudades dormitorios, dentro o fuera del término de la gran ciudad, demandan soluciones administrativas de conjunto que superen los esquemas municipales tradicionales” (Barrero, 1993. Esto lleva a definir el problema de estudio de como la aglomeración de población en áreas superiores a las ciudades tradicionales en América Latina, constituyen formas diferentes a los planos nacionales y municipales, por lo que urge crear condiciones para el bienestar de sus ciudadanos. Es necesario para esto, el comprender el sistema político de manera dinámica y variable, el cual esta íntimamente ligado a la constitución a la deriva estructural de las sociedades, pero sobretodo al gobierno de la ciudad, elemento fundante de la civilización occidental en la cual estamos situados.

  18. Estudio del CH interestelar

    Science.gov (United States)

    Olano, C.; Lemarchand, G.; Sanz, A. J.; Bava, J. A.

    El objetivo principal de este proyecto consiste en el estudio de la distribución y abundancia del CH en nubes interestelares a través de la observación de las líneas hiperfinas del CH en 3,3 GHz. El CH es una molécula de amplia distribución en el espacio interestelar y una de las pocas especies que han sido observadas tanto con técnicas de radio como ópticas. Desde el punto de vista tecnológico se ha desarrollado un cabezal de receptor que permitirá la realización de observaciones polarimétricas en la frecuencia de 3,3 GHz, con una temperatura del sistema de 60 K y un ancho de banda de 140 MHz, y que será instalado en el foco primario de la antena parabólica del IAR. El cabezal del receptor es capaz de detectar señales polarizadas, separando las componentes de polarización circular derecha e izquierda. Para tal fin el cabezal consta de dos ramas receptoras que amplificarán la señal y la trasladarán a una frecuencia más baja (frecuencia intermedia), permitiendo de esa forma un mejor transporte de la señal a la sala de control para su posterior procesamiento. El receptor además de tener características polarimétricas, podrá ser usado en el continuo y en la línea, utilizando las ventajas observacionales y de procesamiento de señal que actualmente posee el IAR.

  19. MEXCODE* CASO DE ESTUDIO

    Directory of Open Access Journals (Sweden)

    Gabriel Arturo García Gómez

    2000-01-01

    Full Text Available El caso plantea la reactivación de un proyecto que se presentó en el año 1995 como alternativa para el desarrollo del centro del Valle y mejora de la eficiencia en el manejo del comercio exterior de la Cuenca Pacífica. El proyecto se revivió a raíz de la necesidad de la compañía patrocinadora de mejorar sus flujos de caja proyectados y la reciente autorización para su funcionamiento. El proyecto es el popularmente denominado “Puerto Seco” de la ciudad de Guadalajara de Buga, internamente nombrado Mexcode. Los estudios iniciales estaban encaminados a que el proyecto fuera manejado por el municipio de Buga, sin embargo, posteriormente se vio la necesidad de buscar que pasara a manos de la empresa privada. El municipio, después de analizar las propuestas de varios inversionistas de la región en las cuales se evaluaba la ubicación dentro de la zona de los predios de sus empresas, su área, proximidad a la línea férrea y a la doble calzada Buga-Tuluá (sitio de paso del 80% de la carga de importación y exportación por Buenaventura y evaluar aspectos relativos a su trayectoria empresarial y compromiso con el desarrollo de la región, decidió otorgarle el proyecto al Grupo Empresarial Agri-Supplies S.A.

  20. Los estudios socioculturales sobre el juego tradicional: una revisión taxonómica

    Directory of Open Access Journals (Sweden)

    Bantulà i Janot, Jaume

    2006-12-01

    Full Text Available This article examines the contributions of the anthropological study of games as a particular subfield of this discipline: the anthropology of games. It includes a detailed description of the anthropology, folklore, ethnology and ethnography based studies that contribute to analyse the socio-cultural aspects of the leisure phenomenon. The author focuses on the various taxonomies formulated to systematise leisure manifestations. The analysis of these classifications points out the limitations of the taxonomies, mainly due to their non-fulfilment of the criteria required in any taxonomy.

    El artículo examina las aportaciones de la antropología al estudio del juego como ámbito específico dentro de la disciplina, la antropología del juego. Se mencionan pormenorizadamente los estudios que, desde la antropología y también desde el folklore, la etnología y la etnografía, se han ocupado de dilucidar los aspectos socioculturales del fenómeno lúdico. En el abordaje de la perspectiva antropológica del juego, el autor hace hincapié en las diversas taxonomías que se han formulado para sistematizar el conjunto de manifestaciones lúdicas. El análisis de las clasificaciones pone de relieve las carencias que presentan, debidas sobre todo al incumplimiento de los criterios exigibles a cualquier taxonomía.

  1. Regulación de contenidos en Internet. Estudio cualitativo, Colombia y derecho comparado, 2008

    Directory of Open Access Journals (Sweden)

    Maribel Villarreal-Buitrago

    2010-03-01

    Full Text Available La incursión de Internet ha creado nuevas formas de información y comunicación, haciendo que las actuales generaciones se socialicen culturalmente bajo la influencia de estas tecnologías en sus diversas variantes, generando una serie de rasgos de comportamiento social y cultural derivados del uso didáctico, académico o lúdico. Sin embargo, el uso de Internet a edades cada vez más tempranas representa no solamente una herramienta educativa útil, sino también puede constituir grandes peligros cuando su uso está relacionado con contenidos inapropiados para su adecuado desarrollo. Lo anterior hace necesario el estudio sobre el abordaje legal de la regulación de contenidos en Internet, para evaluar la manera como se protegen los derechos de los sujetos intervinientes en este proceso. Por otro lado, es importante también el estudio del impacto y uso de esta herramienta tecnológica a nivel del núcleo familiar, para entender mejor cuáles pueden ser los mecanismos sociales apropiados para el uso constructivo de Internet. La presente investigación involucra estos dos aspectos con el fin de unir las perspectivas legal y social en un análisis conjunto que permita una visión más integral de este problema de gran interés a nivel global.

  2. A Bayesian Approach to Period Searching in Solar Coronal Loops

    Science.gov (United States)

    Scherrer, Bryan; McKenzie, David

    2017-03-01

    We have applied a Bayesian generalized Lomb–Scargle period searching algorithm to movies of coronal loop images obtained with the Hinode X-ray Telescope (XRT) to search for evidence of periodicities that would indicate resonant heating of the loops. The algorithm makes as its only assumption that there is a single sinusoidal signal within each light curve of the data. Both the amplitudes and noise are taken as free parameters. It is argued that this procedure should be used alongside Fourier and wavelet analyses to more accurately extract periodic intensity modulations in coronal loops. The data analyzed are from XRT Observation Program #129C: “MHD Wave Heating (Thin Filters),” which occurred during 2006 November 13 and focused on active region 10293, which included coronal loops. The first data set spans approximately 10 min with an average cadence of 2 s, 2″ per pixel resolution, and used the Al-mesh analysis filter. The second data set spans approximately 4 min with a 3 s average cadence, 1″ per pixel resolution, and used the Al-poly analysis filter. The final data set spans approximately 22 min at a 6 s average cadence, and used the Al-poly analysis filter. In total, 55 periods of sinusoidal coronal loop oscillations between 5.5 and 59.6 s are discussed, supporting proposals in the literature that resonant absorption of magnetic waves is a viable mechanism for depositing energy in the corona.

  3. Competition between shock and turbulent heating in coronal loop system

    CERN Document Server

    Matsumoto, Takuma

    2016-01-01

    2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfv\\'{e}n waves excited in the photosphere is the target of the present study. The coronal structure is reproduced in our simulations as a natural consequence of the transportation and dissipation of Alfv\\'{e}n waves. Further, the coronal structure is maintained as the spatial resolution is changed from 25 to 3 km, although the temperature at the loop top increases with the spatial resolution. The heating mechanisms change gradually across the magnetic canopy at a height of 4 Mm. Below the magnetic canopy, both the shock and the MHD turbulence are dominant heating processes. Above the magnetic canopy, the shock heating rate reduces to less than 10 % of the total heating rate while the MHD turbulence provides significant energy to balance the radiative cooling and thermal conduction loss or gain. The i...

  4. Investigation of Coronal Large Scale Structures Utilizing Spartan 201 Data

    Science.gov (United States)

    Guhathakurta, Madhulika

    1998-01-01

    Two telescopes aboard Spartan 201, a small satellite has been launched from the Space Shuttles, on April 8th, 1993, September 8th, 1994, September 7th, 1995 and November 20th, 1997. The main objective of the mission was to answer some of the most fundamental unanswered questions of solar physics-What accelerates the solar wind and what heats the corona? The two telescopes are 1) Ultraviolet Coronal Spectrometer (UVCS) provided by the Smithsonian Astrophysical Observatory which uses ultraviolet emissions from neutral hydrogen and ions in the corona to determine velocities of the coronal plasma within the solar wind source region, and the temperature and density distributions of protons and 2) White Light Coronagraph (WLC) provided by NASA's Goddard Space Flight Center which measures visible light to determine the density distribution of coronal electrons within the same region. The PI has had the primary responsibility in the development and application of computer codes necessary for scientific data analysis activities, end instrument calibration for the white-light coronagraph for the entire Spartan mission. The PI was responsible for the science output from the WLC instrument. PI has also been involved in the investigation of coronal density distributions in large-scale structures by use of numerical models which are (mathematically) sufficient to reproduce the details of the observed brightness and polarized brightness distributions found in SPARTAN 201 data.

  5. Coronal heating by resonant absorption: The effects of chromospheric coupling

    NARCIS (Netherlands)

    Belien, A. J. C.; Martens, P. C. H.; Keppens, R.

    1999-01-01

    We present the first 2.5 dimensional numerical model calculations of the nonlinear wave dynamics and heating by resonant absorption in coronal loops with thermal structuring of the transition region and higher chromosphere. The numerical calculations were done with the Versatile Advection Code. The

  6. Closed-Field Coronal Heating Driven by Wave Turbulence

    CERN Document Server

    Downs, Cooper; Mikić, Zoran; Linker, Jon A; Velli, Marco

    2016-01-01

    To simulate the energy balance of coronal plasmas on macroscopic scales, we often require the specification of the coronal heating mechanism in some functional form. To go beyond empirical formulations and to build a more physically motivated heating function, we investigate the wave-turbulence-driven (WTD) phenomenology for the heating of closed coronal loops. Our implementation is designed to capture the large-scale propagation, reflection, and dissipation of wave turbulence along a loop. The parameter space of this model is explored by solving the coupled WTD and hydrodynamic evolution in 1D for an idealized loop. The relevance to a range of solar conditions is also established by computing solutions for over one hundred loops extracted from a realistic 3D coronal field. Due to the implicit dependence of the WTD heating model on loop geometry and plasma properties along the loop and at the footpoints, we find that this model can significantly reduce the number of free parameters when compared to traditiona...

  7. Data-driven coronal evolutionary model of active region 11944.

    Science.gov (United States)

    Kazachenko, M.

    2014-12-01

    Recent availability of systematic measurements of vector magnetic fields and Doppler velocities has allowed us to utilize a data-driven approach for modeling observed active regions (AR), a crucial step for understanding the nature of solar flare initiation. We use a sequence of vector magnetograms and Dopplergrams from the Helioseismic and Magnetic Imager (HMI) aboard the SDO to drive magnetofrictional (MF) model of the coronal magnetic field in the the vicinity of AR 11944, where an X1.2 flare on January 7 2014 occurred. To drive the coronal field we impose a time-dependent boundary condition based on temporal sequences of magnetic and electric fields at the bottom of the computational domain, i.e. the photosphere. To derive the electric fields we use a recently improved poloidal-toroidal decomposition (PTD), which we call the ``PTD-Doppler-FLCT-Ideal'' or PDFI technique. We investigate the results of the simulated coronal evolution, compare those with EUV observations from Atmospheric Imaging Assembly (AIA) and discuss what we could learn from them. This work is a a collaborative effort from the UC Berkeley Space Sciences Laboratory (SSL), Stanford University, and Lockheed-Martin and is a part of Coronal Global Evolutionary (CGEM) Model, funded jointly by NASA and NSF.

  8. Quantifying the Significance of Substructure in Coronal Loops

    Science.gov (United States)

    McKeough, K. B. D.; Kashyap, V.; McKillop, S.

    2014-12-01

    A method to infer the presence of small-scale substructure in SDO/AIA (Atmospheric Imaging Assembly on the Solar Dynamics Observatory) images of coronal loops is developed. We can classify visible loop structure based on this propensity to show substructure which puts constraints on contemporary solutions to the coronal heating problem. The method uses the Bayesian algorithm Low-count Image Reconstruction and Analysis (LIRA) to infer the multi-scale component of the loops which describes deviations from a smooth model. The increase in contrast of features in this multi-scale component is determined using a statistic that estimates the sharpness across the image. Regions with significant substructure are determined using p-value upper bounds. We are able to locate substructure visible in Hi-C (High-Resolution Coronal Imager) data that are not salient features in the corresponding AIA image. Looking at coronal loops at different regions of the Sun (e.g., low-lying structure and loops in the upper corona) we are able to map where detectable substructure exists and thus the influence of the nanoflare heating process. We acknowledge support from AIA under contract SP02H1701R from Lockheed-Martin to SAO.

  9. Arthroscopic Treatment of Medial Femoral Condylar Coronal Fractures and Nonunions

    Science.gov (United States)

    Ercin, Ersin; Bilgili, M. Gokhan; Basaran, S. Hakan; Baca, Emre; Kural, Cemal; Avkan, M. Cevdet

    2013-01-01

    Nonunion of medial femoral condylar coronal fractures are uncommon. In neglected Hoffa fractures despite nonunion, there is a risk of missing accompanying ligamentous and intra-articular injuries. Neither preoperative clinical examination nor magnetic resonance imaging showed these injuries before arthroscopy. Arthroscopy before internal fixation gives additional information and changes the surgical protocol for these fractures and nonunions. PMID:24400191

  10. Competition between shock and turbulent heating in coronal loop system

    Science.gov (United States)

    Matsumoto, Takuma

    2016-11-01

    2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfvén waves excited in the photosphere is the target of this study. The coronal structure is reproduced in our simulations as a natural consequence of the transportation and dissipation of Alfvén waves. Further, the coronal structure is maintained as the spatial resolution is changed from 25 to 3 km, although the temperature at the loop top increases with the spatial resolution. The heating mechanisms change gradually across the magnetic canopy at a height of 4 Mm. Below the magnetic canopy, both the shock and the MHD turbulence are dominant heating processes. Above the magnetic canopy, the shock heating rate reduces to less than 10 per cent of the total heating rate while the MHD turbulence provides significant energy to balance the radiative cooling and thermal conduction loss or gain. The importance of compressibility shown in this study would significantly impact on the prospects of successful MHD turbulence theory in the solar chromosphere.

  11. The Relationship of Coronal Mass Ejections to Streamers

    CERN Document Server

    Subramanian, P; Rich, N B; Howard, R A; Subramanian, Prasad

    1999-01-01

    We have examined images from the Large Angle Spectroscopic Coronagraph (LASCO) to study the relationship of Coronal Mass Ejections (CMEs) to coronal streamers. We wish to test the suggestion (Low 1996) that CMEs arise from flux ropes embedded in a streamer erupting, thus disrupting the streamer. The data span a period of two years near sunspot minimum through a period of increased activity as sunspot numbers increased. We have used LASCO data from the C2 coronagraph which records Thomson scattered white light from coronal electrons at heights between 1.5 and 6R_sun. Maps of the coronal streamers have been constructed from LASCO C2 observations at a height of 2.5R_sun at the east and west limbs. We have superposed the corresponding positions of CMEs observed with the C2 coronagraph onto the synoptic maps. We identified the different kinds of signatures CMEs leave on the streamer structure at this height (2.5R_sun). We find four types of CMEs with respect to their effect on streamers: 1. CMEs that disrupt the s...

  12. Estudio con imágenes de la cefalea

    Directory of Open Access Journals (Sweden)

    Claudia Jimena Ortiz Liévano

    2012-08-01

    Full Text Available El objetivo de este artículo es brindar al clínico pautas para el uso racional y adecuado de los avances tecnológicos en imaginología, para de esta manera lograr un criterio multidisciplinario en el momento de tomar una decisión buscando el beneficio del paciente sin someterlo a exámenes de poca utilidad. Se realizó una búsqueda sistemática de la literatura médica acerca de la cefalea abarcando su fisiopatología, clasificación y, específicamente, el uso de imágenes diagnósticas. Para ello se hizo búsqueda en diferentes bases de datos según las palabras claves indicadas. El abordaje clínico y la diferenciación entre el tipo de cefalea es primordial para decidir el beneficio y la necesidad del uso de imágenes diagnósticas. Las neuroimágenes no son comúnmente solicitadas en pacientes con cefalea primaria, se comienza la sospecha clínica ante la presencia de señales de alarma. Las cefaleas secundarias requieren un estudio más extenso en los cuales se incluye la toma de imágenes radiológicas. Teniendo en cuenta los beneficios de la TC y la RM que se exponen en esta revisión, la TC es preferida en situaciones de urgencia, y para aquellas que no lo son, la RM es más adecuada.

  13. ANÁLISIS DE FACTORES PROTECTORES EN EL ABORDAJE DEL MALTRATO INFANTIL DESDE LA MIRADA CLÍNICA

    Directory of Open Access Journals (Sweden)

    Gabriela Morelato

    2015-01-01

    Full Text Available El objetivo de este trabajo fue explorar desde una mirada clínica la presencia de los factoresprotectores necesarios para otorgar el alta en un proceso terapéutico de casos de maltrato in-fantil confirmados, según la opinión de los profesionales especialistas en su abordaje. Desdela perspectiva cualitativa, se utilizó una muestra no probabilística ocasional constituida por 51médicos, psicólogos, trabajadores sociales y otras disciplinas afines, especialistas en el abordajede casos de maltrato infantil. Como instrumentos, se implementaron entrevistas y grupos deenfoque. Los resultados señalan la necesidad de la evaluación y fortalecimiento de las funcionesparentales. Además, se rescataron notablemente los recursos y potencialidades propios del niñoy de la familia, los recursos institucionales y los del equipo de salud. Esta propuesta se orienta aintegrar la investigación con la reflexión acerca de las prácticas en el ámbito del maltrato infan-til, con el fin de mejorar las intervenciones clínicas.

  14. Magnetic Field in the Gravitationally Stratified Coronal Loops

    Indian Academy of Sciences (India)

    B. N. Dwivedi; A. K. Srivastava

    2015-03-01

    We study the effect of gravitational stratification on the estimation of magnetic fields in the coronal loops. By using the method of MHD seismology of kink waves for the estimation of magnetic field of coronal loops, we derive a new formula for the magnetic field considering the effect of gravitational stratification. The fast-kink wave is a potential diagnostic tool for the estimation of magnetic field in fluxtubes. We consider the eleven kink oscillation cases observed by TRACE between July 1998 and June 2001. We calculate magnetic field in the stratified loops (str) and compare them with the previously calculated absolute magnetic field (abs). The gravitational stratification efficiently affects the magnetic field estimation in the coronal loops as it affects also the properties of kink waves. We find ≈22% increment in the magnetic field for the smallest ( = 72 Mm) while ≈42% increment in the absolute magnetic field for the longest ( = 406 Mm) coronal loops. The magnetic fields str and abs also increase with the number density, if the loop length does not vary much. The increment in the magnetic field due to gravitational stratification is small at the lower number densities, however, it is large at the higher number densities. We find that damping time of kink waves due to phase-mixing is less in the case of gravitationally stratified loops compared to nonstratified ones. This indicates the more rapid damping of kink waves in the stratified loops. In conclusion, we find that the gravitational stratification efficiently affects the estimation of magnetic field and damping time estimation especially in the longer coronal loops.

  15. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    Science.gov (United States)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  16. On the nature of transverse coronal waves revealed by wavefront dislocations

    CERN Document Server

    Ariste, A López; Arregui, I; Khomenko, E; Collados, M

    2015-01-01

    Coronal waves are an important aspect of the dynamics of the plasma in the corona. Wavefront dislocations are topological features of most waves in nature and also of magnetohydrodynamic waves. Are there dislocations in coronal waves? The finding and explanation of dislocations may shed light on the nature and characteristics of the propagating waves, their interaction in the corona and in general on the plasma dynamics. We positively identify dislocations in coronal waves observed by the Coronal Multi-channel Polarimeter (CoMP) as singularities in the Doppler shifts of emission coronal lines. We study the possible singularities that can be expected in coronal waves and try to reproduce the observed dislocations in terms of localization and frequency of appearance. The observed dislocations can only be explained by the interference of a kink and a sausage wave modes propagating with different frequencies along the coronal magnetic field. In the plane transverse to the propagation, the cross-section of the osc...

  17. Trata: Esclavitud invisibilizada en Costa Rica. Estudio de cinco casos

    Directory of Open Access Journals (Sweden)

    Marianela Méndez-Marenco

    2013-12-01

    Full Text Available La trata de personas con fines de explotación sexual comercial es una problemática solapada en Costa Rica. Resulta necesario conocer este fenómeno, puesto que cada día más ciudadanos son atrapados y sometidos a una forma de esclavitud, que denigra su integridad física, psicológica, social y espiritual. A partir de las experiencias vividas como profesional en una organización sin fines de lucro (ONG con un programa para esta población, hizo evidente el desconocimiento y los excesivos prejuicios sobre las víctimas en la sociedad. Se explora el hecho de que la información sobre este fenómeno en Costa Rica es escasa y el abordaje psicológico lo es aún más. La investigación tiene sus bases en la metodología cualitativa descriptiva; se propone un diseño fenomenológico que parte de la teoría humanista del Análisis Transaccional de Berne (1976 para efectuar estudio múltiple de casos. La muestra estuvo constituida por un grupo de cinco mujeres, que se encontraron en proceso de restauración en la ONG bajo las categorías de análisis “Trata de personas con fines de explotación sexual comercial nacional” (dentro de Costa Rica, “Avasallamientos” y “Desarrollo personal”. Los resultados identificaron avasallamientos, a los que fueron sometidas las mujeres de esta muestra, antes, durante y después de ser captadas en la trata. Asimismo, se analiza cómo el desarrollo de las mujeres víctimas de trata en este estudio se ve obstaculizado por dichos avasallamientos y cómo algunas lograron obtener el crecimiento personal a pesar de lo sucedido.

  18. Estudio de Rodilla Flotante en pacientes del Hospital Clinico Viedma

    Directory of Open Access Journals (Sweden)

    Omar Marcelo Vargas Fuentes

    2011-06-01

    Full Text Available Se denomina “Rodilla Flotante” a la combinación de fractura de fémur y tibia ipsilaterales. La incidencia exacta se desconoce, pero tiene un abordaje terapéutico complejo, una alta tasa de complicaciones y una elevada mortalidad.El presente estudio busca determinar los aspectos relacionados con esta patología en nuestro medio y analizarlos de una manera integral, realizándose para esto un estudio descriptivo y longitudinal retrospectivo abarcando 18 meses (de julio 2008 a diciembre 2009 que incluye a 17 pacientes con diagnóstico de “Rodilla Flotante” ingresados en el Servicio de Ortopedia y Traumatología del Hospital Clínico Viedma. Los resultados mostraronque esta lesión equivale al 1,9 % de los casos atendidos por este servicio. Siendo el 82,35% hombres. La edad promedio fue de 34 años. El mecanismo de producción más frecuente: accidentes en motocicleta (41,2%, seguido de atropellados (29,4%. En cuanto a la clasificación la mayor parte fue tipo I de Fraser (68,8%. El tratamiento quirúrgico definitivo se aplicó entre el 5° y 14° día en el 73.3%, mayormente usando clavos centro medulares en fémur y tibia. Los resultados del tratamiento fueron: excelentes 40%, buenos 33.3%, regulares 20% y pobres en el 6,6% según la escala de Karlstrom y Olerud. Las lesiones asociadas: TEC (80%, fracturas de pelvis (60%, trauma abdominal cerrado (60% y trauma de tórax (33,3%. Dentro de las complicaciones, un paciente falleció por fallamultiorgánica, otro concluyó en amputación, y cinco presentaron infección.Por lo que se concluye que en general los aspectos relacionados con esta patología, su presentación y tratamiento en nuestro medio, son similares a los que se encuentran descritos en la literatura médica.

  19. Estudios longitudinales: concepto y particularidades

    Directory of Open Access Journals (Sweden)

    Miguel Delgado Rodríguez

    2004-01-01

    Full Text Available En la presente revisión se analiza el concepto de estudio longitudinal. Los libros de texto de epidemiología actuales en general no lo definen, mientras que sí lo hacen los tratados de estadística. Se habla más de «datos longitudinales» que de «estudios longitudinales». El estudio longitudinal implica la existencia de medidas repetidas (más de dos a lo largo de un seguimiento. Sería pues un subtipo de estudio de cohortes que, a diferencia de los de tipo tabla de vida, permite inferencias a nivel individual y analizar cambios en diferentes variables (exposiciones y efectos y transiciones entre diferentes estados de salud. Las particularidades de este tipo de diseño hace que se tenga que prestar atención especial al control de calidad durante su ejecución, a los abandonos durante el seguimiento, y a los datos perdidos en algunas de las mediciones. El análisis debe tener en cuenta las medidas repetidas y esto es lo que confiere finalmente a un estudio su carácter longitudinal.

  20. Standing sausage modes in coronal loops with plasma flow

    Science.gov (United States)

    Li, Bo; Chen, Shao-Xia; Xia, Li-Dong; Yu, Hui

    2014-08-01

    Context. Magnetohydrodynamic waves are important for diagnosing the physical parameters of coronal plasmas. Field-aligned flows appear frequently in coronal loops. Aims: We examine the effects of transverse density and plasma flow structuring on standing sausage modes trapped in coronal loops, and examine their observational implications in the context of coronal seismology. Methods: We model coronal loops as straight cold cylinders with plasma flow embedded in a static corona. An eigen-value problem governing propagating sausage waves is formulated and its solutions are employed to construct standing modes. Two transverse profiles are distinguished, and are called profiles E and N. A parameter study is performed on the dependence of the maximum period Pmax and cutoff length-to-radius ratio (L/a)cutoff in the trapped regime on the density parameters (ρ0/ρ∞ and profile steepness p) and the flow parameters (its magnitude U0 and profile steepness u). Results: For either profile, introducing a flow reduces Pmax obtainable in the trapped regime relative to the static case. The value of Pmax is sensitive to p for profile N, but is insensitive to p for profile E. By far the most important effect a flow introduces is to reduce the capability for loops to trap standing sausage modes: (L/a)cutoff may be substantially reduced in the case with flow relative to the static one. In addition, (L/a)cutoff is smaller for a stronger flow, and for a steeper flow profile when the flow magnitude is fixed. Conclusions: If the density distribution can be described by profile N, then measuring the sausage mode period can help deduce the density profile steepness. However, this practice is not feasible if profile E more accurately describes the density distribution. Furthermore, even field-aligned flows with magnitudes substantially smaller than the ambient Alfvén speed can make coronal loops considerably less likely to support trapped standing sausage modes. Appendix A is available in

  1. Coronal Abundance Anomalies in Solar-Like Stars

    Science.gov (United States)

    Laming, John

    We propose to model the trend of coronal abundance anomalies observed in a sample of solar-like stars by Wood & Linsky (2010). Dwarf stars of similar spectral type to the Sun show what has become known as a FIP (First Ionization Potential) Effect, where elements with first ionization potential below about 10 eV are enhanced in abundance in the corona by a factor of about 3 - 4. Stars of later spectral type show a diminished FIP effect, with the anomaly disappearing at about K5 spectral type. Beyond this, M dwarf stars show an inverse FIP effect, with the low FIP ions becoming depleted in the stellar corona, by factors of order 2.5 - 3. The solar case of positive FIP effect has been successfully interpreted as being due to the action of the ponderomotive force associated with chromospheric Alfven waves. In conditions in which upgoing Alfven waves are transmitted into coronal loops, or in which coronally generated waves reflect at loop footpoints, the ponderomotive force is directed upwards, and accelerates chromospheric ions (the low FIP elements) into the corona. Neutral atoms are not affected. The inverse FIP effect can arise when upward propagating chromospheric Alfven waves are reflected back down again at coronal loop footpoints, due to a mismatch between the wave frequency and the loop resonance. We propose to study stars for which parameters like asteroseismic oscillation frequencies, coronal abundance anomalies, and chromospheric structure are known. As well as constraining coronal magnetic fields and loop resonances in these stars, we expect important insights into the nature of stellar dynamos since the M dwarfs in the sample (with inverse FIP effect) are at or near the fully convective limit. Finally, we will be able to assess potential fractionation in the O/Ne abundance ratio. Drake & Testa (2005) argued that Ne is depleted in the solar corona relative to O, but not in the coronae of more active stars. Our FIP models provide some support for this in the

  2. MODELO DIDÁCTICO BASADO EN LA CREATIVIDAD Y ORIENTADO AL ABORDAJE DE LA EDUCACIÓN ALIMENTARIA Y NUTRICIONAL, EN EL NIVEL DE EDUCACION INICIAL

    Directory of Open Access Journals (Sweden)

    Ernesto Elías De La Cruz Sánchez

    2013-08-01

    investigación permitió generar un aporte didáctico orientado al abordaje de la educación alimentaria y nutricional basado en la creatividad para el nivel de Educación Inicial. El modelo se sustentó en las diferentes dimensiones emergentes que permiten interpretar el comportamiento alimentario del ser humano, en las teorías interaccionistas de la creatividad relacionadas con la enseñanza y el aprendizaje en la Educación Inicial. El estudio se ubicó en una investigación cualitativa, de naturaleza fenomenológica interpretativa y de enfoque etnometodológico, centrado en la comprensión de la realidad expresada por los sujetos, el investigador, la praxis educativa en el aula de preescolar y en la comprensión del acto alimentario. Los sujetos %u2013informantes clave- de la investigación se seleccionaron de modo intencional y en total fueron 3 especialistas en nutrición-medicina (INN, Fundación Bengoa y CANIA, 3 docentes universitarios en Educación Preescolar y 6 maestras del Centro Nacional Bolivariano de Educación Inicial, ubicado en Petare, Estado Miranda, y contexto del estudio. Se utilizó como técnicas de recolección de información: la entrevista cualitativa, la observación participante y las conversaciones grupales. Se emplearon como instrumentos: el cuaderno de anotaciones y la guía de entrevista. Para el procesamiento de la información se asumió la teoría fundamentada y el método comparativo continuo propuesto por Strauss y Corbin (2002 y el apoyo en la herramienta de Atlas-ti, versión 5.0. La investigación arrojó: un modelo didáctico basado en la creatividad orientado a sustentar un enfoque creativo para la enseñanza de la educación alimentaria y nutricional en el Nivel de Educación Inicial, el cual incluye recomendaciones para el docente, los padres, la escuela y una sintesis de doce (12 estrategias didácticas para ser incorporadas en la rutina escolar. La validez se determinó por juicio de experto, en base a 10 criterios: integral

  3. El componente educativo en el abordaje integral del asma bronquial The educational component in an integrated approach to bronchial asthma

    Directory of Open Access Journals (Sweden)

    María Paola Fasciglione

    2010-04-01

    Full Text Available El asma bronquial es una enfermedad inflamatoria crónica de las vías respiratorias cuya prevalencia está aumentando en el mundo. Actualmente no se dispone de un tratamiento curativo, y el objetivo principal de todo abordaje es el control de la enfermedad y la optimización de la calidad de vida de los pacientes. En este sentido, durante las últimas décadas se han estado implementando y evaluando programas de intervención complementarios a los tratamientos médicos convencionales. Gran parte de éstos consisten en intervenciones educativas o incluyen algún tipo de componente educativo. El objetivo del presente trabajo fue analizar las características y el impacto de las intervenciones educativas en el asma, a través de: a revisión actualizada sobre los diferentes tipos de intervenciones educativas desarrolladas e implementadas para el asma; b identificación de aspectos comunes a todas estas intervenciones; c análisis de los hallazgos de la investigación referidos a su impacto sobre la salud y la calidad de vida de los pacientes. Se concluye que las intervenciones educativas son efectivas para mejorar la salud y la calidad de vida de los pacientes con asma, y para reducir el uso y el costo de recursos sanitarios. Estos hallazgos señalan la importancia de incluir el componente educativo como parte esencial del abordaje integral de esta población clínica. Asimismo, la complejidad inherente al proceso educativo pone de manifiesto la necesidad del trabajo conjunto y complementario entre diferentes profesionales de la salud.Bronchial asthma is an inflammatory chronic disease of the respiratory tract whose prevalence is increasing worldwide. Since there is no curative treatment available, the principal objective of every approach is to control the disease and to improve the quality of life of patients. Over the last few decades, intervention programs supplementing conventional medical treatments have been tested and implemented. The

  4. Claves para pensar en la construcción de un objeto de investigación complejo: decisiones teóricometodológicas en un abordaje multimétodo sobre niños/as, adolescentes y jóvenes que trabajan en las calles (La Plata, Buenos Aires, Argentina

    Directory of Open Access Journals (Sweden)

    María Eugenia Rausky

    2016-01-01

    Full Text Available El artículo da cuenta de las decisiones teórico-metodológicas puestas en juego en una investigación empírica sobre niños/as, adolescentes y jóvenes que trabajan y/o viven en la calle en la ciudad de La Plata (capital de la Provincia de Buenos Aires, Argentina. La misma buscar reconocer la magnitud y particularidades del fenómeno en cuestión en dicha ciudad–en la que nunca se llevó a cabo una investigación de estas características– a través de un abordaje metodológico sustentado en un diseño mixto de tipo secuencial. Esta presentación en particular, sitúa su eje de reflexión en la importancia de explicitar a la comunidad científica cómo se van articulando las decisiones teóricas y metodológicas en un proceso de investigación que aborda un objeto complejo. El trabajo se organiza en tres apartados: en el primero se explicitan las preguntas que se formulan en este estudio y su relevancia; en el segundo se abordan los conceptos orientadores de la investigación –tanto teóricos como operativos-; en el tercero se da cuenta del conjunto de decisiones metodológicas consideradas a fin de llevar adelante el estudio, focalizando en lo realizado en la primera fase del trabajo de campo –un censo orientado a relevar a la totalidad de sujetos que integran las unidades de análisis-. Por último, en las conclusiones de destaca la importancia de brindar elementos que contribuyan a investigaciones que parten de intereses similares, como así también dar cuenta de las decisiones puestas en juego para la construcción y abordaje de un objeto de indagación complejo.

  5. un objeto de estudio emergente

    Directory of Open Access Journals (Sweden)

    Vanesa Aidée Ramírez Vázquez

    2007-01-01

    Full Text Available El interés de este artículo es mostrar, de manera muy general, los textos que la revista Estudios sobre las Culturas Contemporáneas (ESCC ha publicado desde su creación refi eridas al campo de las Tecnologías de Información y Comunicación (TIC. No se incluyen los estudios sobre la radio y la televisión pues se considera que merecen un tratamiento especial como medios masivos de comunicación con mayor tiempo en el escenario social; se centra, en cambio, en los estudios relativos a las computadoras, Internet, videojuegos, celulares, satélites, redes, chat, lo que se ha dado en llamar Nuevas Tecnologías de Información y Comunicación (NTIC.

  6. An Estimate of Solar Wind Velocity Profiles in a Coronal Hole and a Coronal Streamer Area (6-40 R(radius symbol)

    Science.gov (United States)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Total electron content data obtained from the Ulysses Solar Corona Experiment (SCE) in 1991 were used to select two data sets, one associated with a coronal hole and the other with coronal streamer crossings. (This is largely equatorial data shortly after solar maximum.) The solar wind velocity profile is estimated for these areas.

  7. Energetic characterisation and statistics of solar coronal brightenings

    CERN Document Server

    Joulin, Vincent; Solomon, Jacques; Guennou, Chloé

    2016-01-01

    To explain the high temperature of the corona, much attention has been paid to the distribution of energy in dissipation events. Indeed, if the event energy distribution is steep enough, the smallest, unobservable events could be the largest contributors to the total energy dissipation in the corona. Previous observations have shown a wide distribution of energies but remain inconclusive about the precise slope. Furthermore, these results rely on a very crude estimate of the energy. On the other hand, more detailed spectroscopic studies of structures such as coronal bright points do not provide enough statistical information to derive their total contribution to heating. We aim at getting a better estimate of the distributions of the energy dissipated in coronal heating events using high-resolution, multi-channel Extreme Ultra-Violet (EUV) data. To estimate the energies corresponding to heating events and deduce their distribution, we detect brightenings in five EUV channels of the Atmospheric Imaging Assembl...

  8. Spatial damping of propagating sausage waves in coronal cylinders

    CERN Document Server

    Guo, Ming-Zhe; Li, Bo; Xia, Li-Dong; Yu, Hui

    2015-01-01

    Sausage modes are important in coronal seismology. Spatially damped propagating sausage waves were recently observed in the solar atmosphere. We examine how wave leakage influences the spatial damping of sausage waves propagating along coronal structures modeled by a cylindrical density enhancement embedded in a uniform magnetic field. Working in the framework of cold magnetohydrodynamics, we solve the dispersion relation (DR) governing sausage waves for complex-valued longitudinal wavenumber $k$ at given real angular frequencies $\\omega$. For validation purposes, we also provide analytical approximations to the DR in the low-frequency limit and in the vicinity of $\\omega_{\\rm c}$, the critical angular frequency separating trapped from leaky waves. In contrast to the standing case, propagating sausage waves are allowed for $\\omega$ much lower than $\\omega_{\\rm c}$. However, while able to direct their energy upwards, these low-frequency waves are subject to substantial spatial attenuation. The spatial damping ...

  9. Coronal heating by the partial relaxation of twisted loops

    CERN Document Server

    Bareford, Michael; Browning, Philippa

    2012-01-01

    Context: Relaxation theory offers a straightforward method for estimating the energy that is released when a magnetic field becomes unstable, as a result of continual convective driving. Aims: We present new results obtained from nonlinear magnetohydrodynamic (MHD) simulations of idealised coronal loops. The purpose of this work is to determine whether or not the simulation results agree with Taylor relaxation, which will require a modified version of relaxation theory applicable to unbounded field configurations. Methods: A three-dimensional (3D) MHD Lagrangian-remap code is used to simulate the evolution of a line-tied cylindrical coronal loop model. This model comprises three concentric layers surrounded by a potential envelope; hence, being twisted locally, each loop configuration is distinguished by a piecewise-constant current profile. Initially, all configurations carry zero-net-current fields and are in ideally unstable equilibrium. The simulation results are compared with the predictions of helicity ...

  10. Nonlinear Dynamics of the Parker Scenario for Coronal Heating

    CERN Document Server

    Rappazzo, A F; Einaudi, G; Dahlburg, R B

    2007-01-01

    The Parker or field line tangling model of coronal heating is studied comprehensively via long-time high-resolution simulations of the dynamics of a coronal loop in cartesian geometry within the framework of reduced magnetohydrodynamics (RMHD). Slow photospheric motions induce a Poynting flux which saturates by driving an anisotropic turbulent cascade dominated by magnetic energy. In physical space this corresponds to a magnetic topology where magnetic field lines are barely entangled, nevertheless current sheets (corresponding to the original tangential discontinuities hypothesized by Parker) are continuously formed and dissipated. Current sheets are the result of the nonlinear cascade that transfers energy from the scale of convective motions ($\\sim 1,000 km$) down to the dissipative scales, where it is finally converted to heat and/or particle acceleration. Current sheets constitute the dissipative structure of the system, and the associated magnetic reconnection gives rise to impulsive ``bursty'' heating ...

  11. On The Fourier And Wavelet Analysis Of Coronal Time Series

    CERN Document Server

    Auchère, F; Bocchialini, K; Buchlin, E; Solomon, J

    2016-01-01

    Using Fourier and wavelet analysis, we critically re-assess the significance of our detection of periodic pulsations in coronal loops. We show that the proper identification of the frequency dependence and statistical properties of the different components of the power spectra provies a strong argument against the common practice of data detrending, which tends to produce spurious detections around the cut-off frequency of the filter. In addition, the white and red noise models built into the widely used wavelet code of Torrence & Compo cannot, in most cases, adequately represent the power spectra of coronal time series, thus also possibly causing false positives. Both effects suggest that several reports of periodic phenomena should be re-examined. The Torrence & Compo code nonetheless effectively computes rigorous confidence levels if provided with pertinent models of mean power spectra, and we describe the appropriate manner in which to call its core routines. We recall the meaning of the default c...

  12. Estimate of Coronal Magnetic Field Strength Using Plasmoid Acceleration Measurement

    Science.gov (United States)

    Choe, G.; Lee, K.; Jang, M.

    2010-12-01

    A method of estimating the lower bound of coronal magnetic field strength in the neighborhood of an ejecting plasmoid is presented. Based on the assumption that the plasma ejecta is within a magnetic island, an analytical expression for the force acting on the ejecta is derived. A rather simple calculation shows that the vertical force acting on a cylinder-like volume, whose lateral surface is a flux surface and whose magnetic axis is parallel to the horizontal, is just the difference in total pressure (magnetic pressure plus plasma pressure) below and above the volume. The method is applied to a limb coronal mass ejection event, and a lower bound of the magnetic field strength just below the CME core is estimated. The method is expected to provide useful information on the strength of reconnecting magnetic field if applied to X-ray plasma ejecta.

  13. Coronal Mass Ejections and Non-recurrent Forbush Decreases

    Science.gov (United States)

    Belov, A.; Abunin, A.; Abunina, M.; Eroshenko, E.; Oleneva, V.; Yanke, V.; Papaioannou, A.; Mavromichalaki, H.; Gopalswamy, N.; Yashiro, S.

    2014-10-01

    Coronal mass ejections (CMEs) and their interplanetary counterparts (interplanetary coronal mass ejections, ICMEs) are responsible for large solar energetic particle events and severe geomagnetic storms. They can modulate the intensity of Galactic cosmic rays, resulting in non-recurrent Forbush decreases (FDs). We investigate the connection between CME manifestations and FDs. We used specially processed data from the worldwide neutron monitor network to pinpoint the characteristics of the recorded FDs together with CME-related data from the detailed online catalog based upon the Solar and Heliospheric Observatory (SOHO)/ Large Angle and Spectrometric Coronagraph (LASCO) data. We report on the correlations of the FD magnitude to the CME initial speed, the ICME transit speed, and the maximum solar wind speed. Comparisons between the features of CMEs (mass, width, velocity) and the characteristics of FDs are also discussed. FD features for halo, partial halo, and non-halo CMEs are presented and discussed.

  14. Polar Coronal Holes During Solar Cycles 22 and 23

    Institute of Scientific and Technical Information of China (English)

    Jun Zhang; J. Woch; S. Solanki

    2005-01-01

    Data from the Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses and synoptic maps from Kitt Peak are used to analyze the polar coronal holes of solar activity cycles 22 and 23 (from 1990 to end of 2003). In the beginning of the declining phase of solar cycles 22 and 23, the north polar coronal holes (PCHs) appear about one year earlier than the ones in the south polar region.The solar wind velocity and the solar wind ionic charge composition exhibit a characteristic dependence on the solar wind source position within a PCH. From the center toward the boundary of a young PCH, the solar wind velocity decreases,coinciding with a shift of the ionic charge composition toward higher charge states.However, for an old PCH, the ionic charge composition does not show any obvious change, although the latitude evolution of the velocity is similar to that of a young PCH.

  15. Global Alfven Waves in Solar Physics: Coronal Heating

    Science.gov (United States)

    de Azevedo, C. A.; de Assis, A. S.

    1990-11-01

    RESUMEN. Se ha demostrado que Ia onda discreta de Alfven puede generar por lo memos un 20% de la energia coronal requerida con densidad de flujo de lO- erg 5 . Las ondas discretas de Alfven son una nueva clase `de ondas de Alfven las cuales pueden describirse por el modelo con que incluye un i6n finito, con frecuencia ciclotr6nica ( /uci # 0) y los efectos del equilibrio de plasma mostrados por Appert, Vaclavik and Villar 1984. ABSTRACT. It has been shown that the Discrete Alfven wave can power at least 20% of the required coronal energy flux density iO- Discrete Alfven waves are a new class of Alfven waves wich can be described by the model with the inclusion of finite ion cyclotron frequency (w/wci 0) and the equilibrium plasma current effects as shown by Appert, Vaclavik and Villar 1984. o,t :, HYDROMAGNETICS - SUN-CORONA

  16. Coronal Structures as Tracers of Sub-Surface Processes

    Indian Academy of Sciences (India)

    Alexei A. PevtSOV; Richard C. Canfield

    2000-09-01

    The solar corona - one of the most spectacular celestial shows and yet one of the most challenging puzzles - exhibits a spectrum of structures related to both the quiet Sun and active regions. In spite of dramatic differences in appearance and physical processes, all these structures share a common origin: they are all related to the solar magnetic field. The origin of the field is beneath the turbulent convection zone, where the magnetic field is not a master but a slave, and one can wonder how much the coronal magnetic field ``remembers" its dynamo origin. Surprisingly, it does. We will describe several observational phenomena that indicate a close relationship between coronal and sub-photospheric processes.

  17. Stellar activity and coronal heating: an overview of recent results

    Science.gov (United States)

    Testa, Paola; Saar, Steven H.; Drake, Jeremy J.

    2015-01-01

    Observations of the coronae of the Sun and of solar-like stars provide complementary information to advance our understanding of stellar magnetic activity, and of the processes leading to the heating of their outer atmospheres. While solar observations allow us to study the corona at high spatial and temporal resolution, the study of stellar coronae allows us to probe stellar activity over a wide range of ages and stellar parameters. Stellar studies therefore provide us with additional tools for understanding coronal heating processes, as well as the long-term evolution of solar X-ray activity. We discuss how recent studies of stellar magnetic fields and coronae contribute to our understanding of the phenomenon of activity and coronal heating in late-type stars. PMID:25897087

  18. Stellar Activity and Coronal Heating: an overview of recent results

    CERN Document Server

    Testa, Paola; Drake, Jeremy

    2015-01-01

    Observations of the coronae of the Sun and of solar-like stars provide complementary information to advance our understanding of stellar magnetic activity, and of the processes leading to the heating of their outer atmospheres. While solar observations allow us to study the corona at high spatial and temporal resolution, the study of stellar coronae allows us to probe stellar activity over a wide range of ages and stellar parameters. Stellar studies therefore provide us with additional tools for understanding coronal heating processes, as well as the long-term evolution of solar X-ray activity. We discuss how recent studies of stellar magnetic fields and coronae contribute to our understanding of the phenomenon of activity and coronal heating in late-type stars.

  19. Inferring the Coronal Density Irregularity from EUV Spectra

    CERN Document Server

    Hahn, Michael

    2016-01-01

    Understanding the density structure of the solar corona is important for modeling both coronal heating and the solar wind. Direct measurements are difficult because of line-of-sight integration and possible unresolved structures. We present a new method for quantifying such structure using density-sensitive EUV line intensities to derive a density irregularity parameter, a relative measure of the amount of structure along the line of sight. We also present a simple model to relate the inferred irregularities to physical quantities, such as the filling factor and density contrast. For quiet Sun regions and interplume regions of coronal holes, we find a density contrast of at least a factor of three to ten and corresponding filling factors of about 10-20%. Our results are in rough agreement with other estimates of the density structures in these regions. The irregularity diagnostic provides a useful relative measure of unresolved structure in various regions of the corona.

  20. Coronal Streamers and Their Associated Solar Wind Streams

    Science.gov (United States)

    Miralles, M. P.; Landi, E.; Cranmer, S. R.; Cohen, O.; Raymond, J. C.

    2012-12-01

    We use the EUV spectrometers aboard SOHO and Hinode and white-light coronagraphs to characterize the physical properties of coronal streamers during Earth/Ulysses quadrature configurations for the previous two solar minimum periods. In addition, comparisons between coronal observations and in situ measurements of solar wind plasma properties are being used to further characterize the origins of slow wind streams. In order to investigate slow solar wind heating and acceleration, we also compare with predictions from three-dimensional MHD models. We aim to use the empirical measurements to distinguish between different proposed physical processes for slow wind acceleration (e.g., waves/turbulence versus reconnection). This work is supported by NASA grant NNX10AQ58G to the Smithsonian Astrophysical Observatory.

  1. Estudio antropológico de redes sociales de madres adolescentes durante el embarazo

    Directory of Open Access Journals (Sweden)

    Lorena Pasarin

    2009-07-01

    Full Text Available La atención de la salud incluye a diversos actores sociales, por ello en su estudio debe contemplarse el papel que adquieren los contextos socioculturales. El estudio de las redes sociales resulta conveniente para abordarlos. Este trabajo presenta una aplicación del análisis de redes sociales como complemento de abordaje metodológico al estudio de las prácticas y comportamientos relacionados con la salud de madres adolescentes durante el período prenatal. Utilizando la herramienta EgoNet, se analiza la estructura de las redes personales identificando redes integradas principalmente por familiares que brindan consejos y prestan ayuda instrumental, actuando como facilitadoras respecto a la realización de los controles de salud. La perspectiva de análisis de redes sociales permitió destacar el papel decisivo que cobran ciertas relaciones personales, funcionando como lazos eficaces que afectan significativamente el accionar de las adolescentes respecto a su salud durante el embarazo.The health care includes several social actors, this implies that its study should consider the role of the sociocultural contexts. The study of social networks is appropriate to address them. This paper presents an application of social network analysis as a complement of the methodological approach for the study of practices and health-related behaviors in adolescents mothers. This structure of personal networks is analyzed by EgoNet sofware. That structure is disscussed by identifying family networks that offer advices and provide instrumental assistance, acting as facilitators for the prenatal health controls. The social networks analysis perspective allows to emphasize the critical role acquired by certain personal relationships, which operate affecting significantly the health actions of the teenagers mothers during pregnancy.

  2. Diagnostics of Coronal Heating in Active-region Loops

    Science.gov (United States)

    Fludra, A.; Hornsey, C.; Nakariakov, V. M.

    2017-01-01

    Understanding coronal heating remains a central problem in solar physics. Many mechanisms have been proposed to explain how energy is transferred to and deposited in the corona. We summarize past observational studies that attempted to identify the heating mechanism and point out the difficulties in reproducing the observations of the solar corona from the heating models. The aim of this paper is to study whether the observed extreme ultraviolet (EUV) emission in individual coronal loops in solar active regions can provide constraints on the volumetric heating function, and to develop a diagnostic for the heating function for a subset of loops that are found close to static thermal equilibrium. We reconstruct the coronal magnetic field from Solar Dynamics Observatory/HMI data using a nonlinear force-free magnetic field model. We model selected loops using a one-dimensional stationary model, with a heating rate dependent locally on the magnetic field strength along the loop, and we calculate the emission from these loops in various EUV wavelengths for different heating rates. We present a method to measure a power index β defining the dependence of the volumetric heating rate EH on the magnetic field, {E}H\\propto {B}β , and controlling also the shape of the heating function: concentrated near the loop top, uniform and concentrated near the footpoints. The diagnostic is based on the dependence of the electron density on the index β. This method is free from the assumptions of the loop filling factor but requires spectroscopic measurements of the density-sensitive lines. The range of applicability for loops of different length and heating distributions is discussed, and the steps to solving the coronal heating problem are outlined.

  3. Projection Effects in Coronal Dimmings and Associated EUV Wave Event

    Science.gov (United States)

    Dissauer, K.; Temmer, M.; Veronig, A. M.; Vanninathan, K.; Magdalenić, J.

    2016-10-01

    We investigate the high-speed (v > 1000 km s‑1) extreme-ultraviolet (EUV) wave associated with an X1.2 flare and coronal mass ejection (CME) from NOAA active region 11283 on 2011 September 6 (SOL2011-09-06T22:12). This EUV wave features peculiar on-disk signatures in particular, we observe an intermittent “disappearance” of the front for 120 s in Solar Dynamics Observatory (SDO)/AIA 171, 193, 211 Å data, whereas the 335 Å filter, sensitive to hotter plasmas (T ∼ 2.5 MK), shows a continuous evolution of the wave front. The eruption was also accompanied by localized coronal dimming regions. We exploit the multi-point quadrature position of SDO and STEREO-A, to make a thorough analysis of the EUV wave evolution, with respect to its kinematics and amplitude evolution and reconstruct the SDO line-of-sight (LOS) direction of the identified coronal dimming regions in STEREO-A. We show that the observed intensities of the dimming regions in SDO/AIA depend on the structures that are lying along their LOS and are the combination of their individual intensities, e.g., the expanding CME body, the enhanced EUV wave, and the CME front. In this context, we conclude that the intermittent disappearance of the EUV wave in the AIA 171, 193, and 211 Å filters, which are channels sensitive to plasma with temperatures below ∼2 MK is also caused by such LOS integration effects. These observations clearly demonstrate that single-view image data provide us with limited insight to correctly interpret coronal features.

  4. A Closer Look at the Alpha Persei Coronal Conundrum

    Science.gov (United States)

    Ayres, Thomas R.

    2017-03-01

    A ROSAT survey of the Alpha Per open cluster in 1993 detected its brightest star, the mid-F supergiant α Persei: the X-ray luminosity and spectral hardness were similar to coronally active late-type dwarf members. Later, in 2010, a Hubble Cosmic Origins Spectrograph SNAPshot of α Per found the far-ultraviolet (FUV) coronal-proxy Si iv unexpectedly weak. This, and a suspicious offset of the ROSAT source, suggested that a late-type companion might be responsible for the X-rays. Recently, a multifaceted program tested that premise. Ground-based optical coronography and near-UV imaging with Hubble Space Telescope (HST) Wide-Field Camera 3 searched for any close-in faint candidate coronal objects, but without success. Then, a Chandra pointing found the X-ray source single and coincident with the bright star. Significantly, the Si iv emissions of α Per, in a deeper FUV spectrum collected by the HST Cosmic Origin Spectrograph as part of the joint program, are aligned well with chromospheric atomic oxygen (which must be intrinsic to the luminous star), within the context of cooler late-F and early-G supergiants, including Cepheid variables. This pointed to the X-rays as the fundamental anomaly. The overluminous X-rays still support the case for a hyperactive dwarf secondary, albeit now spatially unresolved. However, an alternative is that α Per represents a novel class of coronal source. Resolving the first possibility now has become more difficult, because the easy solution—a well-separated companion—has been eliminated. Testing the other possibility will require a broader high-energy census of the early-F supergiants.

  5. EUV and Coronagraphic Observations of Coronal Mass Ejections

    Indian Academy of Sciences (India)

    Durgesh Tripathi

    2006-06-01

    The Large Angle Spectrometric Coronagraph (LASCO) and Extreme-ultraviolet Imaging Telescope (EIT) onboard Solar and Heliospheric Observatory (SOHO) provide us with unprecedented multi-wavelength observations helping us to understand different dynamic phenomena on the Sun and in the corona. In this paper we discuss the association between post-eruptive arcades (PEAs) detected by EIT and white-light coronal mass ejections (CMEs) detected by LASCO/C2 telescope.

  6. Energetic characterisation and statistics of solar coronal brightenings

    Science.gov (United States)

    Buchlin, Eric; Solomon, Jacques; Joulin, Vincent; Guennou, Chloé

    2016-07-01

    To explain the high temperature of the corona, much attention has been paid to the distribution of energy in dissipation events, which might be caused by turbulent reconnection. Indeed, if the event energy distribution is steep enough, the smallest, unobservable events could be the largest contributors to the total energy dissipation in the corona. Previous observations have shown a wide distribution of energies but remain inconclusive about the precise slope. Furthermore, these results rely on a very crude estimate of the energy. On the other hand, more detailed spectroscopic studies of structures such as coronal bright points do not provide enough statistical information to derive their total contribution to heating. We aim at getting a better estimate of the distributions of the energy dissipated in coronal heating events using high-resolution, multi-channel Extreme Ultra-Violet (EUV) data. To estimate the energies corresponding to heating events and deduce their distribution, we detect brightenings in five EUV channels of the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO). We combine the results of these detections and we use maps of temperature and emission measure derived from the same observations to compute the energies. We obtain distributions of areas, durations, intensities, and energies (thermal, radiative, and conductive) of events. These distributions are power-laws, and we find also power-law correlations between event parameters. The energy distributions indicate that the energy from a population of events like the ones we detect represents a small contribution to the total coronal heating, even when extrapolating to smaller scales. The main explanations for this are how heating events can be extracted from observational data, and the incomplete knowledge of the thermal structure and processes in the coronal plasma attainable from available observations.

  7. An estimate of solar wind velocity profiles in an coronal hole and a coronal streamer area (6-40 solar radius)

    Science.gov (United States)

    Paetzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Using the total electron content data obtained by the Ulysses Solar Corona Experiment during the superior solar conjunction in summer 1991, we selected two data sets, one associated with a coronal hole and the other one with coronal streamer crossings. By doing this data splitting, we find two entirely different density profiles varying as r(exp -2.7) and r(exp -2.3) for the coronal hole and coronal streamers, respectively. Assuming mass flux conservation from the inner corona to one AU, an estimate for the velocity profiles or acceleration in these two different regions can be determined. The more negative exponent of the coronal hole density profile indicates a more extended heating and acceleration region or more flaring, or both. Various possible explanations will be discussed.

  8. Intermediate Inclinations of Type 2 Coronal-Line Forest AGN

    CERN Document Server

    Rose, Marvin; Crenshaw, Michael; Glidden, Ana

    2015-01-01

    Coronal-Line Forest Active Galactic Nuclei (CLiF AGN) are remarkable in the sense that they have a rich spectrum of dozens of coronal emission lines (e.g. [FeVII], [FeX] and [NeV]) in their spectra. Rose, Elvis & Tadhunter (2015) suggest that the inner obscuring torus wall is the most likely location of the coronal line region in CLiF AGN, and the unusual strength of the forbidden high ionization lines is due to a specific AGN-torus inclination angle. Here we test this suggestion using mid-IR colours (4.6$\\mu$m-22$\\mu$m) from the Wide-Field Infrared Survey Explorer (WISE) for the CLiF AGN. We use the Fischer et al. (2014) result that showed that as the AGN-torus inclination becomes more face on, the Spitzer 5.5$\\mu$m to 30$\\mu$m colours become bluer. We show that the [W2-W4] colours for the CLiF AGN ($\\langle$[W2-W4]$\\rangle$ = 5.92$\\pm$0.12) are intermediate between SDSS type 1 ($\\langle$[W2-W4]$\\rangle$ = 5.22$\\pm$0.01) and type 2 AGN ($\\langle$[W2-W4]$\\rangle$ = 6.35$\\pm$0.03). This implies that the AG...

  9. Solar coronal plumes and the fast solar wind

    CERN Document Server

    Dwivedi, B N

    2015-01-01

    The spectral profiles of the coronal Ne viii line at 77 nm have different shapes in quiet-Sun regions and coronal holes (CHs). A single Gaussian fit of the line profile provides an adequate approximation in quiet-Sun areas, whereas a strong shoulder on the long-wavelength side is a systematic feature in CHs. Although this has been noticed since 1999, no physical reason for the peculiar shape could be given. In an attempt to identify the cause of this peculiarity, we address three problems that could not be conclusively resolved in a review article by a study team of the International Space Science Institute (ISSI; Wilhelm et al. 2011) : (1) The physical processes operating at the base and inside of plumes as well as their interaction with the solar wind (SW). (2) The possible contribution of plume plasma to the fast SW streams. (3) The signature of the first-ionization potential (FIP) effect between plumes and inter-plume regions (IPRs). Before the spectroscopic peculiarities in IPRs and plumes in polar coron...

  10. Spatial damping of propagating sausage waves in coronal cylinders

    Science.gov (United States)

    Guo, Ming-Zhe; Chen, Shao-Xia; Li, Bo; Xia, Li-Dong; Yu, Hui

    2015-09-01

    Context. Sausage modes are important in coronal seismology. Spatially damped propagating sausage waves were recently observed in the solar atmosphere. Aims: We examine how wave leakage influences the spatial damping of sausage waves propagating along coronal structures modeled by a cylindrical density enhancement embedded in a uniform magnetic field. Methods: Working in the framework of cold magnetohydrodynamics, we solve the dispersion relation (DR) governing sausage waves for complex-valued, longitudinal wavenumber k at given real angular frequencies ω. For validation purposes, we also provide analytical approximations to the DR in the low-frequency limit and in the vicinity of ωc, the critical angular frequency separating trapped from leaky waves. Results: In contrast to the standing case, propagating sausage waves are allowed for ω much lower than ωc. However, while able to direct their energy upward, these low-frequency waves are subject to substantial spatial attenuation. The spatial damping length shows little dependence on the density contrast between the cylinder and its surroundings, and depends only weakly on frequency. This spatial damping length is of the order of the cylinder radius for ω ≲ 1.5vAi/a, where a and vAi are the cylinder radius and the Alfvén speed in the cylinder, respectively. Conclusions: If a coronal cylinder is perturbed by symmetric boundary drivers (e.g., granular motions) with a broadband spectrum, wave leakage efficiently filters out the low-frequency components.

  11. Fast-sausage oscillations in coronal loops with smooth boundary

    Science.gov (United States)

    Lopin, I.; Nagorny, I.

    2014-12-01

    Aims: The effect of the transition layer (shell) in nonuniform coronal loops with a continuous radial density profile on the properties of fast-sausage modes are studied analytically and numerically. Methods: We modeled the coronal waveguide as a structured tube consisting of a cord and a transition region (shell) embedded within a magnetic uniform environment. The derived general dispersion relation was investigated analytically and numerically in the context of frequency, cut-off wave number, and the damping rate of fast-sausage oscillations for various values of loop parameters. Results: The frequency of the global fast-sausage mode in the loops with a diffuse (or smooth) boundary is determined mainly by the external Alfvén speed and longitudinal wave number. The damping rate of such a mode can be relatively low. The model of coronal loop with diffuse boundary can support a comparatively low-frequency, global fast-sausage mode of detectable quality without involving extremely low values of the density contrast. The effect of thin transition layer (corresponds to the loops with steep boundary) is negligible and produces small reductions of oscillation frequency and relative damping rate in comparison with the case of step-function density profile. Seismological application of obtained results gives the estimated Alfvén speed outside the flaring loop about 3.25 Mm/s.

  12. The Temperature-Dependent Nature of Coronal Dimmings

    CERN Document Server

    Robbrecht, Eva

    2010-01-01

    The opening-up of the magnetic field during solar eruptive events is often accompanied by a dimming of the local coronal emission. From observations of filament eruptions recorded with the Extreme-Ultraviolet Imager on STEREO during 2008-2009, it is evident that these dimmings are much more pronounced in 19.5 nm than in the lower-temperature line 17.1 nm, as viewed either on the disk or above the limb. We conclude that most of the cooler coronal plasma is not ejected but remains gravitationally bound when the loops open up. This result is consistent with Doppler measurements by Imada and coworkers, who found that the upflow speeds in a transient coronal hole increased dramatically above a temperature of 1 MK; it is also consistent with the quasistatic behavior of polar plumes, as compared with the hotter interplume regions that are the main source of the fast solar wind. When the open flux reconnects and closes down again, the trapped plasma is initially heated to such high temperatures that it is no longer v...

  13. Disappearance of a coronal hole induced by a filament activation

    CERN Document Server

    Lin, Ma; Xiao-Li, Yan; Zhi-Ke, Xue

    2014-01-01

    We present a rare observation of direct magnetic interaction between an activating filament and a coronal hole (CH). The filament was a quiescent one located at the northwest of the CH. It underwent a nonradial activation, during which filament material constantly fell and intruded into the CH. As a result, the CH was clearly destroyed by the intrusion. Brightenings appeared at the boundaries and in the interior of the CH, meanwhile, its west boundaries began to retreat and the area gradually shrank. It is noted that the CH went on shrinking after the end of the intrusion and finally disappeared entirely. Following the filament activation, three coronal dimmings (D1-D3) were formed, among which D1 and D2 persisted throughout the complete disappearance of the CH. The derived coronal magnetic configuration shows that the filament was located below an extended loop system which obviously linked D1 to D2. By comparison with this result of extrapolation, our observations imply that the interaction between the fila...

  14. Projection effects in coronal dimmings and associated EUV wave event

    CERN Document Server

    Dissauer, Karin; Veronig, Astrid M; Vanninathan, Kamalam; Magdalenić, Jasmina

    2016-01-01

    We investigate the high-speed ($v >$ 1000 km s$^{-1}$) extreme-ultraviolet (EUV) wave associated with an X1.2 flare and coronal mass ejection (CME) from NOAA active region 11283 on 2011 September 6 (SOL2011-09-06T22:12). This EUV wave features peculiar on-disk signatures, in particular we observe an intermittent "disappearance" of the front for 120 s in SDO/AIA 171, 193, 211 {\\AA} data, whereas the 335 {\\AA} filter, sensitive to hotter plasmas (T$\\sim$2.5 MK), shows a continuous evolution of the wave front. The eruption was also accompanied by localized coronal dimming regions. We exploit the multi-point quadrature position of SDO and STEREO-A, to make a thorough analysis of the EUV wave evolution, with respect to its kinematics and amplitude evolution and reconstruct the SDO line-of-sight (LOS) direction of the identified coronal dimming regions in STEREO-A. We show that the observed intensities of the dimming regions in SDO/AIA depend on the structures that are lying along their LOS and are the combination ...

  15. More of the Inconvenient Truth About Coronal Dimmings

    CERN Document Server

    McIntosh, Scott W; Leamon, Robert J

    2009-01-01

    We continue the investigation of a CME-driven coronal dimming from December 14 2006 using unique high resolution imaging of the chromosphere and corona from the Hinode spacecraft. Over the course of the dimming event we observe the dynamic increase of non-thermal line broadening of multiple emission lines as the CME is released and the corona opens; reaching levels seen in coronal holes. As the corona begins to close, refill and brighten, we see a reduction of the non-thermal broadening towards the pre-eruption level. The dynamic evolution of non-thermal broadening is consistent with the expected change of Alfven wave amplitudes in the magnetically open rarefied dimming region, compared to the dense closed corona prior to the CME. The presented data reinforce the belief that coronal dimmings must be temporary sources of the fast solar wind. It is unclear if such a rapid transition in the thermodynamics of the corona to a solar wind state has an effect on the CME itself.

  16. The Density of Coronal Plasma in Active Stellar Coronae

    CERN Document Server

    Testa, P; Peres, G; Testa, Paola; Drake, Jeremy J.; Peres, Giovanni

    2004-01-01

    We have analyzed high-resolution X-ray spectra of a sample of 22 active stars observed with the High Energy Transmission Grating Spectrometer on {\\em Chandra} in order to investigate their coronal plasma density. Densities where investigated using the lines of the He-like ions O VII, Mg XI, and Si XIII. While Si XIII lines in all stars of the sample are compatible with the low-density limit, Mg XI lines betray the presence of high plasma densities ($> 10^{12}$ cm$^{-3}$) for most of the sources with higher X-ray luminosity ($> 10^{30}$ erg/s); stars with higher $L_X$ and $L_X/L_{bol}$ tend to have higher densities at high temperatures. Ratios of O VII lines yield much lower densities of a few $10^{10}$ cm$^{-3}$, indicating that the ``hot'' and ``cool'' plasma resides in physically different structures. Our findings imply remarkably compact coronal structures, especially for the hotter plasma emitting the Mg XI lines characterized by coronal surface filling factor, $f_{MgXI}$, ranging from $10^{-4}$ to $10^{-...

  17. MHD modeling of coronal loops: the transition region throat

    CERN Document Server

    Guarrasi, M; Orlando, S; Mignone, A; Klimchuk, J A

    2014-01-01

    The expansion of coronal loops in the transition region may considerably influence the diagnostics of the plasma emission measure. The cross sectional area of the loops is expected to depend on the temperature and pressure, and might be sensitive to the heating rate. The approach here is to study the area response to slow changes in the coronal heating rate, and check the current interpretation in terms of steady heating models. We study the area response with a time-dependent 2D MHD loop model, including the description of the expanding magnetic field, coronal heating and losses by thermal conduction and radiation from optically thin plasma. We run a simulation for a loop 50 Mm long and quasi-statically heated to about 4 MK. We find that the area can change substantially with the quasi-steady heating rate, e.g. by ~40% at 0.5 MK as the loop temperature varies between 1 and 4 MK, and, therefore, affects the interpretation of DEM(T) curves.

  18. Interpretation of the coronal magnetic field configuration of the Sun

    CERN Document Server

    Li, Bo; Yu, Hui

    2012-01-01

    The origin of the heliospheric magnetic flux on the Sun, and hence the origin of the solar wind, is a topic of hot debate.While the prevailing view is that the solar wind originates from outside coronal streamer helmets, there also exists the suggestion that the open magnetic field spans a far wider region.Without the definitive measurement of the coronal magnetic field, it is difficult to resolve the conflict between the two scenarios without doubt.We present two 2-dimensional, Alfv\\'enic-turbulence-based models of the solar corona and solar wind, one with and the other without a closed magnetic field region in the inner corona.The purpose of the latter model is to test whether it is possible to realize a picture suggested by polarimetric measurements of the corona using the FeXIII 10747\\AA\\ line, where open magnetic field lines seem to penetrate the streamer base.The boundary conditions at the coronal base are able to account for important observational constraints, especially those on the magnetic flux dis...

  19. Current systems of coronal loops in 3D MHD simulations

    CERN Document Server

    Warnecke, Jörn; Bingert, Sven; Peter, Hardi

    2016-01-01

    We study the magnetic field and current structure associated with a coronal loop. Through this we investigate to what extent the assumptions of a force-free magnetic field break down. We analyse a three-dimensional MHD model of the solar corona in an emerging active region with the focus on the structure of the forming coronal loops. The lower boundary of this simulation is taken from a model of an emerging active region. As a consequence of the emerging magnetic flux a coronal loop formes self-consistently. We investigate the current density along magnetic field lines inside (and outside) this loop and study the magnetic and plasma properties in and around this loop. The loop is defined as the bundle of field lines that coincides with enhanced emission in extreme UV. We find that the total current along the emerging loop changes its sign from being antiparallel to parallel to the magnetic field. Around the loop the currents form a complex non-force-free helical structure. This is directly related to a bipola...

  20. Field Topology Analysis of a Long-lasting Coronal Sigmoid

    Science.gov (United States)

    Savcheva, A. S.; van Ballegooijen, A. A.; DeLuca, E. E.

    2012-01-01

    We present the first field topology analysis based on nonlinear force-free field (NLFFF) models of a long-lasting coronal sigmoid observed in 2007 February with the X-Ray Telescope on Hinode. The NLFFF models are built with the flux rope insertion method and give the three-dimensional coronal magnetic field as constrained by observed coronal loop structures and photospheric magnetograms. Based on these models, we have computed horizontal maps of the current and the squashing factor Q for 25 different heights in the corona for all six days of the evolution of the region. We use the squashing factor to quantify the degree of change of the field line linkage and to identify prominent quasi-separatrix layers (QSLs). We discuss the major properties of these QSL maps and devise a way to pick out important QSLs since our calculation cannot reach high values of Q. The complexity in the QSL maps reflects the high degree of fragmentation of the photospheric field. We find main QSLs and current concentrations that outline the flux rope cavity and that become characteristically S-shaped during the evolution of the sigmoid. We note that, although intermittent bald patches exist along the length of the sigmoid during its whole evolution, the flux rope remains stable for several days. However, shortly after the topology of the field exhibits hyperbolic flux tubes (HFT) on February 7 and February 12 the sigmoid loses equilibrium and produces two B-class flares and associated coronal mass ejections (CMEs). The location of the most elevated part of the HFT in our model coincides with the inferred locations of the two flares. Therefore, we suggest that the presence of an HFT in a coronal magnetic configuration may be an indication that the system is ready to erupt. We offer a scenario in which magnetic reconnection at the HFT drives the system toward the marginally stable state. Once this state is reached, loss of equilibrium occurs via the torus instability, producing a CME.

  1. Imaging solar coronal magnetic structures in 3D

    Science.gov (United States)

    Cartledge, N. P.

    The study of solar coronal structures and, in particular prominences, is a key part of understanding the highly complex physical mechanisms occurring in the Sun's atmosphere. Solar prominences are important in their own right and some of the most puzzling questions in solar theory have arisen through their study. For example, how do they form and how is their mass continuously replenished? How can the magnetic field provide their continuous support against gravity over time periods of several months? How can such cool, dense material exist in thermal equilibrium in the surrounding coronal environment? Why do they erupt? A study of their structure and that of the surrounding medium is important in determining the nature of the coronal plasma and magnetic field. Also, prominences are closely associated with other key phenomena such as coronal mass ejections and eruptive solar flares which occur as a prominence loses equilibrium and rises from the solar surface. Our current understanding of these fascinating structures is extremely limited and we know very little about their basic global structure. In fact, recent prominence observations have caused our basic paradigms to be challenged (Priest, 1996) and so we must set up new models in order to gain even a fundamental understanding. Prominences are highly nonlinear, three-dimensional structures. Large feet (or barbs) reach out from the main body of a prominence and reach down to the photosphere where the dense material continuously drains away. These provide a real clue to the three-dimensional nature of the coronal field and its relation to the photospheric field. It is important, therefore, to make stereographic observations of prominences in order to gain a basic understanding of their essentially three-dimensional nature and attempt to formulate new paradigms for their structure and evolution. There is no doubt that the study of prominences in three dimensions is a crucial exercise if we are to develop a better

  2. Coronal structure analysis based on the potential field source surface modeling and total solar eclipse observation

    Science.gov (United States)

    Muhamad, Johan; Mumtahana, Farahhati; Sutastio, Heri; Imaduddin, Irfan; Putri, Gerhana P.

    2016-11-01

    We constructed global coronal magnetic fields of the Sun during the Total Solar Eclipse (TSE) 9 March 2016 by using Potential Field Source Surface (PFSS) model. Synoptic photospheric magnetogram data from Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO) was used as a boundary condition to extrapolate the coronal magnetic fields of the Sun. This extrapolated structure was analyzed by comparing the alignment of the fields from the model with coronal structure from the observation. We also used observational data of coronal structure during the total solar eclipse to know how well the model agree with the observation. As a result, we could identify several coronal streamers which were produced by the large closed loops in the lower regime of the corona. This result verified that the PFSS extrapolation can be used as a tool to model the inner corona with several constraints. We also discussed how the coronal structure can be used to deduce the phase of the solar cycle.

  3. Optimizing Global Coronal Magnetic Field Models Using Image-Based Constraints

    CERN Document Server

    Jones, Shaela I; Uritsky, Vadim M

    2015-01-01

    The coronal magnetic field directly or indirectly affects a majority of the phenomena studied in space physics. It provides energy for coronal heating, controls the release of coronal mass ejections (CMEs), and drives heliospheric and magnetospheric activity, yet the coronal magnetic field itself has proven difficult to measure. This difficulty has prompted a decades-long effort to develop accurate, timely, models of the field - an effort that continues today. We have developed a method for improving global coronal magnetic field models by incorporating the type of morphological constraints which could be derived from coronal images. Here we report promising initial tests of this approach on two theoretical problems, and discuss opportunities for application.

  4. Simbolismo e identidad en las tierras bajas del paraná: un abordaje contextual del arte mobiliar cerámico

    OpenAIRE

    Flavia V. Ottalagano

    2010-01-01

    Se intenta una aproximación al simbolismo de los grupos humanos que habitaron las Tierras Bajas del río Paraná Medio durante el Holoceno Tardío, a través de un abordaje contextual de su arte mobiliar cerámico. En base a esto, se procura abrir la discusión hacia temáticas interconectadas y escasamente investigadas, como ser la identidad, las relaciones inter-grupales e intra-grupales de las poblaciones asentadas en el área en momentos prehispánicos. El carácter probablemente cotidiano de estos...

  5. Evidencia científica en torno al abordaje terapéutico de la fascitis plantar en corredores: Revisión sistemática

    OpenAIRE

    Vicente Liras, Maider

    2014-01-01

    RESUMEN: La fascitis plantar afecta aproximadamente al 10% de los corredores durante su carrera deportiva. Objetivos: Investigar acerca de la fascitis plantar, la evidencia científica en torno al abordaje terapéutico de esta lesión en corredores. Métodos: Se consultó los principales buscadores y bases de datos biomédicas: PubMed, PEDro (Physiotherapy Evidence Database), The Cochane Library y Lilacs IBECS, con restricción de fecha, en castellano, inglés y francés. Se seleccionaron ensayo...

  6. Estrategias para el abordaje de la neurofobia: aprendizaje basado en la experiencia : El modelo de Kolb y el enfoque fenomenológico

    OpenAIRE

    Pedersoli, Luis Carlos; Pedersoli Castellani, Luis Martín

    2011-01-01

    El abordaje de la “neurofobia” entendida según Jozefowicz como “el miedo a las neurociencias en general y a la clínica neurológica en particular por parte de médicos y estudiantes que conduce a la parálisis del pensamiento y de la acción” resulta una tarea compleja. La consideración de los estilos de aprendizaje predominantes en cada persona a través del modelo de Kolb y la forma de presentar la experiencia clínica mediante el enfoque fenomenológico, constituyen aproximaciones para el tratami...

  7. Canino mandibular incluido: presentación de un caso atípico de abordaje quirúrgico por vía lingual

    OpenAIRE

    Rius Pastor, J.; Conde Mir, Ma Núria; Berini Aytés, Leonardo; Gay Escoda, Cosme; Jaume Riera, C.

    1996-01-01

    Se presenta el caso de un paciente varón que tenía el canino temporal inferior derecho no exfoliado a los 15 años de edad; a la exploración se descubrió que existía el canino permanente totalmente incluído, con la particularidad de que estaba asociado a un quiste folicular y que la posible causa de inclusión era la presencia de un premolar supernumerario también retenido; otra rareza a destacar es que se hizo un abordaje quirúrgico mixto, vestibular para el premolar supernumerario y lingual p...

  8. Conocimiento y Prácticas del personal docente con relación al abordaje del proceso de duelo en adolescentes.

    OpenAIRE

    Viriam Leiva Díaz; María Elena López Bermúdez; Aurora Torres Madrigal

    2012-01-01

    En el siguiente artículo se presentan los resultados parciales sobre el conocimiento y prácticas del personal docente en el abordaje del proceso de duelo en adolescentes del Instituto Superior Julio Acosta García en San Ramón. Dicha investigación se realizó con un enfoque cuantitativo, descriptivo. Para la recolección de la información se aplicó un cuestionario, el cual permitió caracterizar y conocer los aspectos mencionados entorno a la temática del proceso de duelo en adolescentes. La info...

  9. Abordaje de la discapacidad en facultades de Psicología de universidades privadas de Bogotá, entre 1998 y 2009

    OpenAIRE

    Mónica Lucía Castelblanco Niño

    2011-01-01

    El objetivo de esta investigación fue conocer el estado del arte sobre el abordaje de la discapacidad en los trabajos de grado para optar al título de psicólogo en universidades privadas de Bogotá. Se utilizó el método de investigación documental Resumenes Analíticos de Investigación, -RAE s- de bases de datos elaborados entre los años 1998 a 2009. Se seleccionaron aquellos que abordaban la discapacidad, discapacidad física, la discapacidad cognitiva, la discapacidad sensorial y la inclusi...

  10. First use of synoptic vector magnetograms for global nonlinear force free coronal magnetic field models

    OpenAIRE

    Tadesse, Tilaye; Wiegelmann, T.; Gosain, S.; Macneice, P.; Pevtsov, Alexei A.

    2013-01-01

    The magnetic field permeating the solar atmosphere is generally thought to provide the energy for much of the activity seen in the solar corona, such as flares, coronal mass ejections (CMEs), etc. To overcome the unavailability of coronal magnetic field measurements, photospheric magnetic field vector data can be used to reconstruct the coronal field. Currently there are several modelling techniques being used to calculate three-dimension of the field lines into the solar atmosphere. For the ...

  11. Una tensa oscuridad: interrogando el abordaje psicosocial de la subjetividad A tense obscurity: inquiring the psychosocial approach of subjectivity

    Directory of Open Access Journals (Sweden)

    Patricia Amigot Leache

    2007-12-01

    Full Text Available Abordamos en este artículo algunas reflexiones en torno al estudio psicosocial de la subjetividad, subrayando el diálogo transdisciplinar y la obra de autores alejados del marco convencional de la Psicología Social. El texto señala algunas de las tensiones y paradojas que el estudio del self plantea, así como algunas de las aportaciones teóricas cruciales para reflexionar acerca de ellas. Brevemente, y con una perspectiva foucaultiana, bosquejaremos los nudos de complejidad en torno al estudio de la historicidad del sujeto, su experiencia temporal y coherente, las dimensiones corporales y materiales, la dimensión inconsciente, la tensión entre sujeción y agencia y el carácter generizado de la subjetividad.This article addresses some reflections considering the psychosocial study of subjectivity, emphasizing the transdisciplinary dialogue and the work of authors that move away from the conventional frame of Social Psychology. The text indicates some of the tensions and paradoxes that arise from the study of the self, as well as some of the crucial theoretical contributions to think about them. Briefly, and with a Foucaultian perspective, we will point out the issues of complexity that encompass studying the historicity of the subject, the temporary and coherent experience, the corporal and material dimensions, the unconscious dimension, the tension between subjection and agency and the gendered characteristic of subjectivity.

  12. Estudio de la prevalencia de un tercer conducto en primeros premolares superiores mediante diafanización

    OpenAIRE

    Katherine Stephanie De la Rosa Fernández; Marcio Alejandro Farfán Chacha

    2016-01-01

    Existen fracasos endodónticos que son relacionados por diferentes causas como: obturación incompleta, filtración coronal y fallos por parte del clínico en identificar o localizar los conductos radiculares y sus ramificaciones. Por este motivo, es básico la noción de la anatomía interna dental y sobre todo es importante tener en cuenta las variaciones que pueden existir en las distintas piezas dentales. Objetivo: El propósito del presente estudio es conocer la cantidad de conductos existentes ...

  13. Charge States of Solar Cosmic Rays and Constraints on Acceleration Times and Coronal Transport

    CERN Document Server

    Ruffolo, D

    1997-01-01

    We examine effects on the charge states of energetic ions associated with gradual solar flares due to shock heating and stripping at high ion velocities. Recent measurements of the mean charges of various elements after the flares of 1992 Oct 30 and 1992 Nov 2 allow one to place limits on the product of the electron density times the acceleration or coronal residence time. In particular, any residence in coronal loops must be for < 0.03 s, which rules out models of coronal transport in loops, such as the bird cage model. The results do not contradict models of shock acceleration of energetic ions from coronal plasma at various solar longitudes.

  14. estudio de un caso brasileño

    Directory of Open Access Journals (Sweden)

    Patricia Sampaio Silva

    2007-01-01

    Full Text Available El presente trabajo se basa en el estudio de tres grandes municipios del semiárido nordeste brasileño –Flores, Floresta y Villa Bella, pertenecientes a un valle particularmente pobre del interior del país–, desde el siglo XVIII hasta la década de 1930. Y tiene un doble objetivo; de un lado, considerar los municipios como actores históricos, con trayectorias propias, que conocen momentos de auge y de decadencia según las diferentes épocas. De otro, repensar el papel de los magistrados de las ciudades del interior, con el propósito de romper el cliché, por largo tiempo difundido, en virtud del cual todo magistrado, como todo funcionario público del interior del país, estaba “a los pies” de los potentados locales, los coronéis. Se trata pues de insertar la historia de los municipios en la transformación que tuvo lugar tanto a nivel local como regional, estableciendo un ir y venir entre la historia “de los municipios” y la historia “en los municipios”.

  15. Estudios de investigación experimentales

    OpenAIRE

    Serra Añó, Pilar

    2016-01-01

    En este vídeo se explican las principales características de los estudios de investigación experimentales, en cuanto a diseño y procedimientos. En concreto se consideran los estudios experimentales (ensayos clínicos aleatorizados y no aleatorizados) y los estudios cuasi-experimentales (diseño de series temporales y experimentos cruzados).

  16. Education for Democratic Citizenship in Educational Institutions: The Socio-educational Approach La educación para una ciudadanía democrática en las instituciones educativas: Su abordaje sociopedagógico

    Directory of Open Access Journals (Sweden)

    Arturo Torres Bugdud

    2013-08-01

    Full Text Available Citizenship education is one of the most relevant topics in education. It comprises key aspects of the student’s personal and social behavior, and has significant points of convergence with other areas of the educational practice. Democracy is emphasized in this paper as an important feature of citizenship education, which requires special attention in terms of its socio-educational approach. Citizenship education may be studied from different scientific disciplines; in this case, the pedagogical approach is studied from the social perspective. The main objective of this paper is to discuss the theoretical basis on the subject matter of this project, through studies conducted in different contexts of the social sciences, underlining the importance of citizenship education today, regardless of the educational level in which it is taught. Analysis-synthesis and historical-logical methods were used to assess the background on the subject, obtaining results that could be developed in the educational institutions, in the future.Recibido 20 de mayo de 2012 • Corregido 17 de junio de 2013 • Aceptado 19 de junio de 2013La educación ciudadana es uno de los temas educativos de mayor actualidad, además de abordar aspectos esenciales de la dimensión personal y social del estudiante, posee puntos de contacto importantes con otras direcciones de la práctica educativa. En este artículo se enfatiza la democracia como cualidad importante de la educación ciudadana que requiere especial atención en su abordaje sociopedagógico. El tema de la educación ciudadana se afronta por diferentes disciplinas científicas, en este caso se acentúa el enfoque pedagógico desde una perspectiva social. El objetivo fundamental de este artículo de reflexión es argumentar los sustentos teóricos sobre esta temática, a través de estudios realizados en diferentes contextos desde el campo de las ciencias sociales, destacando la importancia que adquiere la educaci

  17. Factores emocionales en el abordaje de las enfermedades cardiovasculares. Valoración actualizada desde la Psicocardiología Emotional Factors in the present a topic of Cardiovascular Diseases. Updated Assessment from Psychocardiology

    Directory of Open Access Journals (Sweden)

    Teresa Rodríguez Rodríguez

    2012-11-01

    Full Text Available El tratamiento de las enfermedades cardiovasculares exige un abordaje desde la multidisciplinariedad, por la presencia de diversos factores en su origen y evolución. La Psicocardiología se encarga de estudiar los factores de orden psicológico vinculados a estas enfermedades. En el presente trabajo se abordan los factores emocionales que repercuten en diferentes padecimientos coronarios, así como el vínculo de estos, con los diferentes tipos de personalidad. Se exponen resultados obtenidos sobre el estudio de diversas emociones en pacientes portadores de infarto agudo del miocardio en fase aguda, y se ilustra cómo realizar la intervención psicológica para lograr el control emocional de estos pacientes porque puede ser útil para los enfermos y en el mejoramiento del cuadro clínico en general. Finalmente se apela a la necesidad de crear una concientización en la comunidad médica, para que no se desestime el papel de factores de índole subjetiva a la hora de prevenir, diagnosticar y tratar cualquier enfermedad cardiaca.The treatment of cardiovascular diseases requires an approach from a variety of disciplines due to the presence of several factors in its origins and evolution. Psychocardiology is responsible for studying the factors related to psychology associated with these diseases. This paper addresses the emotional factors affecting different coronary heart diseases, as well as the link among them, with different types of personalities. Results on the study of various emotions in patients with acute myocardial infarction in the acute phase are presented and it is illustrates how to achieve psychological intervention for emotional control in these patients because it can be useful for them in the improvement of the overall clinical condition. Finally, it is appealed to the need of creating an awareness in the medical community not to discard the role of subjectivity when it comes to preventing, diagnosing and treating any cardiac

  18. La implementación del abordaje colaborativo en Costa Rica: hacia una integración entre la psiquiatría y la atención primaria

    Directory of Open Access Journals (Sweden)

    Ricardo Millán-González

    2014-12-01

    Full Text Available Introducción: la Organización Mundial de la Salud ha postulado que para reducir la brecha de tratamiento, la inversión en salud mental debe centrarse en la atención primaria. El abordaje colaborativo es una metodología estandarizada que cuenta con evidencia científica de efectividad y costo -efectividad en estas poblaciones. Objetivo: discutir la implementación del abordaje colaborativo en Costa Rica, a partir de una revisión bibliográfica dirigida, y realizar una valoración crítica del modelo actual costarricense. Diseño: revisión bibliográfica, análisis del modelo nacional y propuesta de aplicación. Resultados: en Costa Rica existe un modelo de atención de referencia, el cual tiene menor sustento científico que el abordaje colaborativo, y posiblemente tiende a aumentar la brecha de tratamiento. Discusión y recomendaciones: el abordaje colaborativo permitiría un mayor reconocimiento de la comorbilidad psiquiátrica, mejoraría las técnicas de abordaje y tratamiento, incrementaría el balance costo - beneficio y, probablemente, disminuiría la brecha de tratamiento. Conclusiones: la mayor parte de los recursos en psiquiatría deben emplearse en el primer nivel de atención. El abordaje colaborativo ha demostrado ser la mejor estrategia de tratamiento de la comorbilidad psiquiátrica en esa población. Su instauración en Costa Rica es viable, debido a la amplia cobertura existente en la atención primaria, y su aplicación debería gestarse desde el Ministerio de Salud, la Caja Costarricense de Seguro Social, y las escuelas de medicina.

  19. Saberes y trayectorias de atención a la salud de poblaciones vulneradas en México: un abordaje interdisciplinario

    Directory of Open Access Journals (Sweden)

    Luz María Espinosa Cortés

    2013-06-01

    Full Text Available El objetivo de este artículo es evidenciar la potencialidad que tiene el abordaje interdisciplinario en la comprensión integral del proceso salud/enfermedad/atención de poblaciones vulneradas de tres comunidades, una rural ubicada en el Estado de Oaxaca (Charco Redondo y dos en la Ciudad de México (Xochimilco y Magdalena Contreras. La experiencia y los saberes (representaciones y prácticas sociales se recuperan desde la perspectiva de sus habitantes, siguiendo la estrategia basada en aproximaciones multi método. Con base en referentes teóricos y metodológicos compartidos, se revisó el material empírico producido en tres investigaciones previas. El abordaje interdisciplinario se orientó hacia la reinterpretación histórica, antropológica y psicosocial de los saberes y de las trayectorias de búsqueda de atención de la población, para lograr una comprensión más amplia e integradora del proceso salud/enfermedad que contribuya a la elaboración de políticas públicas orientadas a mejorar las condiciones de salud de poblaciones vulneradas. Al final del trabajo se plantean algunas reflexiones sobre los alcances, limitaciones y los retos para impulsar la investigación interdisciplinaria.

  20. The Evolution and Space Weather Effects of Solar Coronal Holes

    Science.gov (United States)

    Krista, Larisza; Gallagher, P.

    2011-05-01

    As solar activity is the foremost important aspect of space weather, the forecasting of flare and CME related transient geomagnetic storms has become a primary initiative. Minor magnetic storms caused by coronal holes (CHs) have also proven to be important due to their long-lasting and recurrent geomagnetic effects. In order to forecast CH related geomagnetic storms, the author developed the Coronal Hole Automated Recognition and Monitoring (CHARM) algorithm to replace the user-dependent CH detection methods commonly used. CHARM uses an intensity thresholding method to identify low intensity regions in EUV or X-ray images. Since CHs are regions of "open” magnetic field and predominant polarity, magnetograms were used to differentiate CHs from other low intensity regions. The Coronal Hole Evolution (CHEVOL) algorithm was developed and used in conjunction with CHARM to study the boundary evolution of CHs. It is widely accepted that the short-term changes in CH boundaries are due to the interchange reconnection between the CH open field lines and small loops. We determined the magnetic reconnection rate and the diffusion coefficient at CH boundaries in order to test the interchange reconnection model. The author also developed the Minor Storm (MIST) package to link CHs to high-speed solar wind (HSSW) periods detected at Earth. Using the algorithm the relationship between CHs, the corresponding HSSW properties, and geomagnetic indices were studied between 2000-2009. The results showed a strong correlation between the velocity and HSSW proton plasma temperature, which indicates that the heating and acceleration of the solar wind plasma in CHs are closely related, and perhaps caused by the same mechanism. The research presented here includes analysis of CHs on small and large spatial/temporal scales, allowing us to further our understanding of CHs as a whole.

  1. Interpretation of the coronal magnetic field configuration of the Sun

    Institute of Scientific and Technical Information of China (English)

    Bo Li; Xing Li; Hui Yu

    2012-01-01

    The origin of the heliospheric magnetic flux on the Sun,and hence the origin of the solar wind,is a topic of hot debate.While the prevailing view is that the solar wind originates from outside the coronal streamer helmets,there also exists the suggestion that the open magnetic field spans a far wider region.Without the definitive measurement of the coronal magnetic field,it is difficult to unambiguously resolve the conflict between the two scenarios.We present two 2-dimensional,Alfvénic-turbulence-based models of the solar corona and solar wind,one with and the other without a closed magnetic field region in the inner corona.The purpose of the latter model is to test whether it is possible to realize a picture suggested by polarimetric measurements of the corona using the Fe ⅩⅢ 10747(A) line,where open magnetic field lines seem to penetrate the streamer base.The boundary conditions at the coronal base are able to account for important observational constraints,especially those on the magnetic flux distribution.Interestingly,the two models provide similar polarized brightness (pB) distributions in the field of view (FOV) of SOHO/LASCO C2 and C3 coronagraphs.In particular,a dome-shaped feature is present in the C2 FOV even for the model without a closed magnetic field.Moreover,both models fit the Ulysses data scaled to 1 AU equally well.We suggest that:1) The pB observations cannot be safely taken as a proxy for the magnetic field topology,as is often implicitly assumed.2) The Ulysses measurements,especially the one showing a nearly uniform distribution with heliocentric latitude of the radial magnetic field,do not rule out the ubiquity of open magnetic fields on the Sun.

  2. Coronal Loops: Observations and Modeling of Confined Plasma

    Directory of Open Access Journals (Sweden)

    Fabio Reale

    2014-07-01

    Full Text Available Coronal loops are the building blocks of the X-ray bright solar corona. They owe their brightness to the dense confined plasma, and this review focuses on loops mostly as structures confining plasma. After a brief historical overview, the review is divided into two separate but not independent parts: the first illustrates the observational framework, the second reviews the theoretical knowledge. Quiescent loops and their confined plasma are considered and, therefore, topics such as loop oscillations and flaring loops (except for non-solar ones, which provide information on stellar loops are not specifically addressed here. The observational section discusses the classification, populations, and the morphology of coronal loops, its relationship with the magnetic field, and the loop stranded structure. The section continues with the thermal properties and diagnostics of the loop plasma, according to the classification into hot, warm, and cool loops. Then, temporal analyses of loops and the observations of plasma dynamics, hot and cool flows, and waves are illustrated. In the modeling section, some basics of loop physics are provided, supplying fundamental scaling laws and timescales, a useful tool for consultation. The concept of loop modeling is introduced and models are divided into those treating loops as monolithic and static, and those resolving loops into thin and dynamic strands. More specific discussions address modeling the loop fine structure and the plasma flowing along the loops. Special attention is devoted to the question of loop heating, with separate discussion of wave (AC and impulsive (DC heating. Large-scale models including atmosphere boxes and the magnetic field are also discussed. Finally, a brief discussion about stellar coronal loops is followed by highlights and open questions.

  3. Estudios de visitantes a museos

    Directory of Open Access Journals (Sweden)

    Keilyn Rodríguez Sánchez

    2011-01-01

    Full Text Available Este artículo ofrece un estudio bibliográfico en torno a las investigaciones sobre la relación entre la museografía y sus visitantes. El objetivo central de este documento consiste en elaborar una clasificación de esos estudios en programas de investigación de manera que sirva de punto de partida para la construcción de una pedagogía del Museo. Para este fin, se utiliza la propuesta de Schulman, sobre tipificación de estudios en programas de investigación y, al respecto, se plantean cuatro tipos: investigaciones centradas en lo museográfico, investigaciones centradas en el comportamiento museal, investigaciones centradas en la interacción dispositivo-visitantes y las investigaciones centradas en la evaluación museográfica. Se concluye que los resultados de investigación de estos programas, junto con el conocimiento de las técnicas de diseño y a la teoría educativa, serían la base central de un planteamiento sobre pedagogía museológica.

  4. Abordaje subcraneal discusión y revisión histórica de la técnica quirúrgica Anterior subcranial approach: Discussion and historical review of the surgical technique

    OpenAIRE

    I. Zubillaga Rodríguez; G. Sánchez Aniceto; J.J. Montalvo Moreno; R. Díaz Lobato

    2009-01-01

    Introducción. La cirugía de la base craneal es en la actualidad una realidad que se ha ido consolidando en las últimas décadas. El vertiginoso avance tecnológico desarrollado ha actuado como motor en la evolución de las técnicas quirúrgicas que abordan dicha región anatómica. Su impulso definitivo se ha cimentado en el concepto básico de equipo multidisciplinario. Material y métodos. Se describe el abordaje subcraneal como alternativa a los tradicionales abordajes a la base craneal anterior. ...

  5. Geoeffectiveness of Coronal Mass Ejections in the SOHO Era

    DEFF Research Database (Denmark)

    Dumbovic, M.; Devos, A.; Vrsnak, B.;

    2014-01-01

    The main objective of the study is to determine the probability distributions of the geomagnetic Dst index as a function of the coronal mass ejection (CME) and solar flare parameters for the purpose of establishing a probabilistic forecast tool for the geomagnetic storm intensity. Several CME...... and flare parameters as well as the effect of successive-CME occurrence in changing the probability for a certain range of Dst index values, were examined. The results confirm some of already known relationships between remotely-observed properties of solar eruptive events and geomagnetic storms, namely...

  6. Magnetic fields, plasmas, and coronal holes - The inner solar system

    Science.gov (United States)

    Burlaga, L. F.

    1979-01-01

    Recent results concerning streams and magnetic fields in the inner solar system are reviewed. Observations have shown that MHD streams are bounded by thin shear layers within 1 AU, probably because they originate in coronal holes which have sharp boundaries. The properties of Alfvenic fluctuations in streams cannot be fully explained on the basis of the hypothesis that they are plane, transverse Alfven waves. A more complete and accurate description might be that they represent nonplanar general Alfven waves weakly coupled to a compressive mode and moving through a medium containing tangential discontinuities and other convected inhomogeneities.

  7. 3D reconstruction methods of coronal structures by radio observations

    Science.gov (United States)

    Aschwanden, Markus J.; Bastian, T. S.; White, Stephen M.

    1992-01-01

    The ability to carry out the three dimensional (3D) reconstruction of structures in the solar corona would represent a major advance in the study of the physical properties in active regions and in flares. Methods which allow a geometric reconstruction of quasistationary coronal structures (for example active region loops) or dynamic structures (for example flaring loops) are described: stereoscopy of multi-day imaging observations by the VLA (Very Large Array); tomography of optically thin emission (in radio or soft x-rays); multifrequency band imaging by the VLA; and tracing of magnetic field lines by propagating electron beams.

  8. El estudio de la educación superior privada en México: un tema pendiente

    Directory of Open Access Journals (Sweden)

    angélica buendía espinosa

    2009-01-01

    Full Text Available En México, el estudio de la Educación Superior Privada (esp no ha ocupado un lugar preponderante en las agendas de investigación, a pesar de la relevancia que las instituciones particulares han recobrado, tanto por la expansión en el número de matrícula estudiantil atendida, a partir de la décadade los ochenta, como por el debate en torno a la comercialización de la educación superior. Este trabajo presenta un resumen de las líneas de investigación sobre el sector privado de la educación superior en México, así como sus principales exponentes. Concluye que el abordaje de la esp a nivel internacional, y en particular en nuestro país, ha sido limitado si lo comparamos con los estudios sobre la educación superior pública y propone algunos temas de investigación que fortalecerían el conocimiento de la educación superior.

  9. Políticas para la inserción laboral de jóvenes: estudios en Latinoamérica y Argentina

    Directory of Open Access Journals (Sweden)

    Paula Isacovich, Argentina

    2015-07-01

    Full Text Available (analítico Este trabajo forma parte de una investigación etnográfica finalizada sobre las relaciones entre jóvenes y políticas de formación e inserción laboral en la Ciudad de Buenos Aires. En ese marco, en el artículo analizo y sintetizo diversas perspectivas de investigaciones en ciencias sociales que enfocaron la inserción laboral juvenil en América Latina desde la escolarización y las políticas de fomento al empleo joven, o bien desde las experiencias de la gente joven en relación con la formación y el trabajo. Concluyo señalando aspectos vacantes de los estudios y sugiriendo abordajes para ampliar la comprensión del tema.

  10. La conducta informativa de los físicos: un estudio cualitativo de usuarios

    Directory of Open Access Journals (Sweden)

    Nancy Diana Gómez

    2001-06-01

    Full Text Available El propósito de este artículo es examinar la conducta informativa en el proceso de búsqueda y uso de la información de físicos que están en proceso o han concluido recientemente su tesis doctoral. Este estudio se realizó desde el abordaje del sense making centrado en el usuario. Se intenta explicar las situaciones comprendidas dentro del proceso de búsqueda y uso de la información, en términos de elección de fuentes, criterios de juicio de relevancia utilizados, estrategias de organización, y estrategias de presentación de la información, tanto como los sentimientos de los físicos y la definición que dan de la informaciónThe work analizes information seeking behavior of students who are in the process of getting a PhD in Physics or who have recently done so. The analysis was made within the sense making approach which is centered in the user. An attempt is made to explain situations in the seek and use of information in terms of the sources, the criteria used to determine its relevance, organizational strategies as well as information presentation strategies. The study also looks at the physicists feelings during the information seeking process and the way the idea of information evolves in their minds throughout their PhD.

  11. La ciudad desde los imaginarios urbanos del sabor: Tunja como caso de estudio

    Directory of Open Access Journals (Sweden)

    Carlos Mario Rodríguez

    2015-06-01

    Full Text Available El artículo presenta los resultados generales de la investigación “Sabores de la ciudad imaginada”, realizada en la ciudad de Tunja, Colombia . Este estudio, hecho desde un enfoque cualitativo y bajo la metodología de análisis de los imaginarios urbanos de la ciudad, se propuso el desarrollo de una lectura de ciudad desde la perspectiva de los habitantes, a partir de la premisa ¿Cuál es el sabor de Tunja? El abordaje al ciudadano se planteó mediante el diseño de tres instrumentos: encuesta, cuestionario e intervención artística, de esta manera, se desarrolló un análisis de las percepciones del sentido del gusto con relación a la ciudad, lo cual demostró que los imaginarios urbanos son expresados, también, por medio de la percepción del sabor y que su análisis permite reconocer relaciones establecidas entre sabores y lugares que tienen que ver con el uso que se le da a los espacios, las rutinas, formas de actuar e ideas comúnmente aceptadas con relación a las características de la ciudad.

  12. Chromospheric and Coronal Activity in the 500 Myr old Open Cluster M37: Evidence for Coronal Stripping?

    Science.gov (United States)

    Núñez, Alejandro; Agüeros, Marcel A.; Covey, Kevin R.; López-Morales, Mercedes

    2017-01-01

    We present the results of a spectroscopic survey to characterize chromospheric activity, as measured by {{H}}α emission, in low-mass members of the 500 Myr old open cluster M37. Combining our new measurements of {{H}}α luminosities ({L}{{H}α }) with previously cataloged stellar properties, we identify saturated and unsaturated regimes in the dependence of the {L}{{H}α }-to-bolometric luminosity ratio, {L}{{H}α }/{L}{bol}, on the Rossby number R o . All rotators with R o smaller than 0.03 ± 0.01 converge to an activity level of {L}{{H}α }/{L}{bol}=(1.27+/- 0.02)× {10}-4. This saturation threshold ({R}o,{sat}=0.03+/- 0.01) is statistically smaller than that found in most studies of the rotation–activity relation. In the unsaturated regime, slower rotators have lower levels of chromospheric activity, with {L}{{H}α }/{L}{bol}(R o ) following a power-law of index β =-0.51+/- 0.02, slightly shallower than that found for a combined ≈650 Myr old sample of Hyades and Praesepe stars. By comparing this unsaturated behavior to that previously found for coronal activity in M37 (as measured via the X-ray luminosity, {L}{{X}}), we confirm that chromospheric activity decays at a much slower rate than coronal activity with increasing R o . While a comparison of {L}{{H}α } and {L}{{X}} for M37 members with measurements of both reveals a nearly 1:1 relation, removing the mass-dependencies by comparing instead {L}{{H}α }/{L}{bol} and {L}{{X}}/{L}{bol} does not provide clear evidence for such a relation. Finally, we find that {R}o,{sat} is smaller for our chromospheric than for our coronal indicator of activity ({R}o,{sat}=0.03+/- 0.01 versus 0.09 ± 0.01). We interpret this as possible evidence for coronal stripping.

  13. Coronal Dynamic Activities in the Declining Phase of a Solar Cycle

    CERN Document Server

    Jang, Minhwan; Hong, Sunhak; Choe, G S

    2016-01-01

    It has been known that some solar activity indicators show a double-peak feature in their evolution through a solar cycle, which is not conspicuous in sunspot number. In this letter, we investigate the high solar dynamic activity in the declining phase of the sunspot cycle by examining the evolution of polar and low latitude coronal hole areas and the statistics of splitting and merging events of coronal holes and coronal mass ejections detected by SOHO/LASCO C3 in solar cycle 23. Although the total coronal hole area is at its maximum near the sunspot minimum, in which polar coronal holes prevail, it shows a comparable second maximum in the declining phase of the cycle, in which low latitude coronal holes are dominant. The events of coronal hole splitting or merging, which are attributed to surface motions of magnetic fluxes, are also mostly populated in the declining phase of the cycle. The far-reaching C3 coronal mass ejections are also over-populated in the declining phase of the cycle. From these results ...

  14. Computed tomography of the sella turcica content in coronal and axial plane

    Energy Technology Data Exchange (ETDEWEB)

    Lovrencic, M.; Kalousek, M.; Klaric, R.; Sekso, M.

    1984-10-01

    Computed tomography of the pituitary fossa in the axial and coronal plane have been performed in 40 patients. The use of both planes has improved diagnostic accuracy through a more exact spatial demonstration. The method has also been reliable in the detection of pituitary microadenomas. The use of both planes has a limited diagnostic accuracy due artefacts in coronal plane.

  15. ABORDAJE DE LA CULTURA DESDE LA INVESTIGACIÓN EN CONTABILIDAD: POSIBILIDADES DE RE-SIGNIFICACIÓN

    Directory of Open Access Journals (Sweden)

    JORGE ANDRÉS SALGADO CASTILLO

    2016-01-01

    Full Text Available El concepto de cultura se ha trabajado en contabilidad principalmente para evaluar las diferen - cias en los sistemas contables y en el control de gestión entre países, lo anterior tiene por objeto caracterizar y sobre todo comparar los elementos principales que impactan a la contabilidad y el control en las culturas nacionales. El trabajo de Hofstede (1980, 1984 es el referente principal de la investigación contable en el ámbito de la cultura, sin embargo no escapa de cuestionamientos por no tomar en cuenta las construcciones de disciplinas que estudian el fenómeno cultural, tales como la antropología cultural, la historia, la sociología, entre otras. El presente trabajo expone los marcos y referentes de la antropología cultural, como elemento importante del análisis de la cultura, posteriormente, se esbozan los referentes utilizados por la contabilidad para el estudio de la cultura, la aplicación en sus estudios y las críticas surgidas.

  16. Cannabis, possible cardiac deaths and the coroner in Ireland.

    LENUS (Irish Health Repository)

    Tormey, W P

    2012-01-10

    BACKGROUND: The elevated risk of triggering a myocardial infarction by smoking cannabis is limited to the first 2 h after smoking. AIM: To examine the possible role of cannabis in cardiac deaths. CASES AND RESULTS: From 3,193 coroners\\' cases over 2 years, there were 13 cases where the clinical information was compatible with a primary cardiac cause of death. An inquest was held in three cases. Myocardial infarction was the primary cause of death in 54%. Other causes were sudden adult death syndrome, sudden death in epilepsy, and poisoning by alcohol and diazepam. Cannabis was mentioned once only on a death certificate, but not as a cause of death. Blood delta9-tetrahydrocannabinol-carboxylic acid was recorded in one case and in no case was plasma tetrahydrocannabinol (THC) measured. CONCLUSIONS: To attribute sudden cardiac death to cannabis, plasma THC should be measured in the toxicology screen in coroners\\' cases where urine cannabinoids are positive. A positive urine cannabinoids immunoassay alone is insufficient evidence in the linkage of acute cardiac death and cannabis.

  17. CONSTRAINTS ON THE UBIQUITY OF CORONAL X-RAY CYCLES

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, John [Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, IL 61801 (United States); Guenther, Hans M.; Wright, Nicholas J., E-mail: hoffma24@illinois.edu, E-mail: guenther@head.cfa.harvard.edu, E-mail: nwright@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2012-11-10

    Stellar activity cycles are known to be a widespread phenomenon amongst moderately active solar- and late-type stars from long-term periodic variations in chromospheric Ca II H and K emission lines, yet to date, only a handful of coronal X-ray cycles are known. We have surveyed serendipitously observed stellar sources in fields observed multiple times in the last decade by XMM-Newton and present our analysis of nine stars from six fields. Since our sample is flux-limited, it is strongly biased toward higher levels of X-ray activity. We fit a single temperature APEC spectrum to each source and search for significant periodicities using a Lomb-Scargle periodogram. We use a Monte Carlo (MC) algorithm to yield robust analysis of the statistical significance of cycle detections and non-detections. None of the nine stellar light curves show any convincing indications of periodicity. From MC simulations, we simulate the detection capabilities of our methodology and, assuming a uniform distribution of cycle periods and strengths over the domain searched, we conclude with 95% confidence that less than 72% of the stars represented by our sample of active stars have 5-13 year coronal X-ray cycles.

  18. Sausage Waves in Transversely Nonuniform Monolithic Coronal Tubes

    Science.gov (United States)

    Lopin, I.; Nagorny, I.

    2015-09-01

    We investigate fast sausage waves in a monolithic coronal magnetic tube, modeled as a local density inhomogeneity with a continuous radial profile. This work is a natural extension of our previous results, obtained for a slab loop model for the case of cylindrical geometry. Using Kneser’s oscillating theorem, we provided the criteria for the existence of trapped and leaky wave regimes as a function of the profile features. For a number of density profiles there are only trapped modes for the entire range of longitudinal wave numbers. The phase speed of these modes tends toward the external Alfvén speed in the long wavelength limit. The generalized results were supported by the analytic solution of the wave equation for the specific density profiles. The approximate Wentzel-Kramers-Brillouin solutions allowed us to obtain the desired dispersion relations and to study their properties as a function of the profile parameters. The multicomponent quasi-periodic pulsations in flaring loops, observed on 2001 May 2 and 2002 July 3, are interpreted in terms of the transversely fundamental trapped fast sausage mode with several longitudinal harmonics in a smooth coronal waveguide.

  19. QUASI-PERIODIC OSCILLATION OF A CORONAL BRIGHT POINT

    Energy Technology Data Exchange (ETDEWEB)

    Samanta, Tanmoy; Banerjee, Dipankar [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Tian, Hui, E-mail: tsamanta@iiap.res.in, E-mail: hui.tian@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-06-20

    Coronal bright points (BPs) are small-scale luminous features seen in the solar corona. Quasi-periodic brightenings are frequently observed in the BPs and are generally linked with underlying magnetic flux changes. We study the dynamics of a BP seen in the coronal hole using the Atmospheric Imaging Assembly images, the Helioseismic and Magnetic Imager magnetogram on board the Solar Dynamics Observatory, and spectroscopic data from the newly launched Interface Region Imaging Spectrograph (IRIS). The detailed analysis shows that the BP evolves throughout our observing period along with changes in underlying photospheric magnetic flux and shows periodic brightenings in different EUV and far-UV images. With the highest possible spectral and spatial resolution of IRIS, we attempted to identify the sources of these oscillations. IRIS sit-and-stare observation provided a unique opportunity to study the time evolution of one footpoint of the BP as the slit position crossed it. We noticed enhanced line profile asymmetry, enhanced line width, intensity enhancements, and large deviation from the average Doppler shift in the line profiles at specific instances, which indicate the presence of sudden flows along the line-of-sight direction. We propose that transition region explosive events originating from small-scale reconnections and the reconnection outflows are affecting the line profiles. The correlation between all these parameters is consistent with the repetitive reconnection scenario and could explain the quasi-periodic nature of the brightening.

  20. Filament Shape Versus Coronal Potential Magnetic Field Structure

    CERN Document Server

    Filippov, Boris

    2015-01-01

    Solar filament shape in projection on disc depends on the structure of the coronal magnetic field. We calculate the position of polarity inversion lines (PILs) of coronal potential magnetic field at different heights above the photosphere, which compose the magnetic neutral surface, and compare with them the distribution of the filament material in H$\\alpha$ chromospheric images. We found that the most of the filament material is enclosed between two polarity inversion lines (PILs), one at a lower height close to the chromosphere and one at a higher level, which can be considered as a height of the filament spine. Observations of the same filament on the limb by the {\\it STEREO} spacecraft confirm that the height of the spine is really very close to the value obtained from the PIL and filament border matching. Such matching can be used for filament height estimations in on-disk observations. Filament barbs are housed within protruding sections of the low-level PIL. On the base of simple model, we show that th...

  1. Physical properties of erupting plasma associated with coronal mass ejections

    Science.gov (United States)

    Lee, J.; Raymond, J. C.; Reeves, K. K.; Moon, Y.; Kim, K.

    2013-12-01

    We investigate the physical properties (temperature, density, and mass) of erupting plasma observed in X-rays and EUV, which are all associated with coronal mass ejections observed by SOHO/LASCO. The erupting plasmas are observed as absorption or emission features in the low corona. The absorption feature provides a lower limit to the cold mass while the emission feature provides an upper limit to the mass of observed plasma in X-ray and EUV. We compare the mass constraints for each temperature response and find that the mass estimates in EUV and XRT are smaller than the total mass in the coronagraph. Several events were observed by a few passbands in the X-rays, which allows us to determine the temperature of the eruptive plasma using a filter ratio method. The temperature of one event is estimated at about 8.6 MK near the top of the erupting plasma. This measurement is possibly an average temperature for higher temperature plasma because the XRT is more sensitive at higher temperatures. In addition, a few events show that the absorption features of a prominence or a loop change to emission features with the beginning of their eruptions in all EUV wavelengths of SDO/AIA, which indicates the heating of the plasma. By estimating the physical properties of the erupting plasmas, we discuss the heating of the plasmas associated with coronal mass ejections in the low corona.

  2. An imaging study of a complex solar coronal radio eruption

    CERN Document Server

    Feng, S W; Song, H Q; Wang, B; Kong, X L

    2016-01-01

    Solar coronal radio bursts are enhanced radio emission excited by energetic electrons accelerated during solar eruptions, studies on which are important for investigating the origin and physical mechanism of energetic particles and further diagnosing coronal parameters. Earlier studies suffered from a lack of simultaneous high-quality imaging data of the radio burst and the eruptive structure in the inner corona. Here we present a study on a complex solar radio eruption consisting of a type II and three reversely-drifting type III bursts, using simultaneous EUV and radio imaging data. It is found that the type II burst is closely associated with a propagating and evolving CME-driven EUV shock structure, originated initially at the northern shock flank and later transferred to the top part of the shock. This source transfer is co-incident with the presence of shock decay and enhancing signatures observed at the corresponding side of the EUV front. The electron energy accelerated by the shock at the flank is es...

  3. Converging Supergranular Flows and the Formation of Coronal Plumes

    Science.gov (United States)

    Wang, Y.-M.; Warren, H. P.; Muglach, K.

    2016-01-01

    Earlier studies have suggested that coronal plumes are energized by magnetic reconnection between unipolar flux concentrations and nearby bipoles, even though magnetograms sometimes show very little minority-polarity flux near the footpoints of plumes. Here we use high-resolution extreme-ultraviolet (EUV) images and magnetograms from the Solar Dynamics Observatory (SDO) to clarify the relationship between plume emission and the underlying photospheric field. We find that plumes form where unipolar network elements inside coronal holes converge to form dense clumps, and fade as the clumps disperse again. The converging flows also carry internetwork fields of both polarities. Although the minority-polarity flux is sometimes barely visible in the magnetograms, the corresponding EUV images almost invariably show loop-like features in the core of the plumes, with the fine structure changing on timescales of minutes or less. We conclude that the SDO observations are consistent with a model in which plume emission originates from interchange reconnection in converging flows, with the plume lifetime being determined by the approximately 1-day evolutionary timescale of the supergranular network. Furthermore, the presence of large EUV bright points and/or ephemeral regions is not a necessary precondition for the formation of plumes, which can be energized even by the weak, mixed-polarity internetwork fields swept up by converging flows.

  4. Observing the formation of flare-driven coronal rain

    CERN Document Server

    Scullion, E; Antolin, P; Wedemeyer, S; Vissers, G; Kontar, E P; Gallagher, P

    2016-01-01

    Flare-driven coronal rain can manifest from rapidly cooled plasma condensations near coronal loop-tops in thermally unstable post-flare arcades. We detect 5 phases that characterise the post-flare decay: heating, evaporation, conductive cooling dominance for ~120 s, radiative / enthalpy cooling dominance for ~4700 s and finally catastrophic cooling occurring within 35-124 s leading to rain strands with s periodicity of 55-70 s. We find an excellent agreement between the observations and model predictions of the dominant cooling timescales and the onset of catastrophic cooling. At the rain formation site we detect co-moving, multi-thermal rain clumps that undergo catastrophic cooling from ~1 MK to ~22000 K. During catastrophic cooling the plasma cools at a maximum rate of 22700 K s-1 in multiple loop-top sources. We calculated the density of the EUV plasma from the DEM of the multi-thermal source employing regularised inversion. Assuming a pressure balance, we estimate the density of the chromospheric componen...

  5. On the Fourier and Wavelet Analysis of Coronal Time Series

    Science.gov (United States)

    Auchère, F.; Froment, C.; Bocchialini, K.; Buchlin, E.; Solomon, J.

    2016-07-01

    Using Fourier and wavelet analysis, we critically re-assess the significance of our detection of periodic pulsations in coronal loops. We show that the proper identification of the frequency dependence and statistical properties of the different components of the power spectra provides a strong argument against the common practice of data detrending, which tends to produce spurious detections around the cut-off frequency of the filter. In addition, the white and red noise models built into the widely used wavelet code of Torrence & Compo cannot, in most cases, adequately represent the power spectra of coronal time series, thus also possibly causing false positives. Both effects suggest that several reports of periodic phenomena should be re-examined. The Torrence & Compo code nonetheless effectively computes rigorous confidence levels if provided with pertinent models of mean power spectra, and we describe the appropriate manner in which to call its core routines. We recall the meaning of the default confidence levels output from the code, and we propose new Monte-Carlo-derived levels that take into account the total number of degrees of freedom in the wavelet spectra. These improvements allow us to confirm that the power peaks that we detected have a very low probability of being caused by noise.

  6. A Study of Fast Flareless Coronal Mass Ejections

    CERN Document Server

    Song, H Q; Ye, D D; Han, G Q; Du, G H; Li, G; Zhang, J; Hu, Q

    2013-01-01

    Two major processes have been proposed to convert the coronal magnetic energy into the kinetic energy of a coronal mass ejection (CME): resistive magnetic reconnection and ideal macroscopic magnetohydrodynamic instability of magnetic flux rope. However, it remains elusive whether both processes play a comparable role or one of them prevails during a particular eruption. To shed light on this issue, we carefully studied energetic but flareless CMEs, \\textit{i.e.}, fast CMEs not accompanied by any flares. Through searching the Coordinated Data Analysis Workshops (CDAW) database of CMEs observed in Solar Cycle 23, we found 13 such events with speeds larger than 1000 km s$^{-1}$. Other common observational features of these events are: (1) none of them originated in active regions; they were associated with eruptions of well-developed long filaments in quiet-Sun regions, (2) no apparent enhancement of flare emissions was present in soft X-ray, EUV and microwave data. Further studies of two events reveal that (1) ...

  7. Forbush decreases associated to Stealth Coronal Mass Ejections

    Science.gov (United States)

    Heber, B.; Wallmann, C.; Galsdorf, D.; Herbst K.; Kühl, P.; Dumbovic, M.; Vršnak, B.; Veronig, A.; Temmer, M.; Möstl, C.; Dalla, S.

    Interplanetary coronal mass ejections (ICMEs) are structures in the solar wind that are the counterparts of coronal mass ejections (CMEs) at the Sun. It is commonly believed that enhanced magnetic fields in interplanetary shocks and solar ejecta as well as the increased turbulence in the solar wind sheath region are the cause of Forbush decreases (FDs) representing decreases of galactic cosmic ray (GCR) intensities. Recently, stealth CMEs i.e.~CMEs with no apparent solar surface association have become a subject in recent studies of solar activity. Whether all of such stealth CMEs can drive a FD is difficult to investigate on the basis of neutron monitor NM measurements because these measurements not only reflect the GCR intensity variation in interplanetary space but also the variation of the geomagnetic field as well as the conditions in the Earth atmosphere. Single detector counter from spacecraft instrumentation, here SOHO and Chandra EPHIN, exceed counting statistic of NMs allowing to determine intensity variation of less than 1 permil in interplanetary space on the basis of 30 minute count rate averages. Here we present the ongoing analysis of eleven stealth CMEs.

  8. Full Halo Coronal Mass Ejections: Arrival at the Earth

    CERN Document Server

    Shen, Chenglong; Pan, Zonghao; Miao, Bin; Ye, Pinzhong; Wang, S

    2014-01-01

    A geomagnetic storm is mainly caused by a front-side coronal mass ejection (CME) hitting the Earth and then interacting with the magnetosphere. However, not all front-side CMEs can hit the Earth. Thus, which CMEs hit the Earth and when they do so are important issues in the study and forecasting of space weather. In our previous work (Shen et al., 2013), the de-projected parameters of the full-halo coronal mass ejections (FHCMEs) that occurred from 2007 March 1 to 2012 May 31 were estimated, and there are 39 front-side events could be fitted by the GCS model. In this work, we continue to study whether and when these front-side FHCMEs (FFHCMEs) hit the Earth. It is found that 59\\% of these FFHCMEs hit the Earth, and for central events, whose deviation angles $\\epsilon$, which are the angles between the propagation direction and the Sun-Earth line, are smaller than 45 degrees, the fraction increases to 75\\%. After checking the deprojected angular widths of the CMEs, we found that all of the Earth-encountered CM...

  9. The 3D structure of Coronal Mass Ejections

    Science.gov (United States)

    Patsourakos, Spiros

    2016-07-01

    Coronal Mass Ejections (CMEs) represent one of the most powerful energy release phenomena in the entire solar system and are a major driver of space weather. Prior to 2006, our observational access to CMEs was limited to single viewpoint remote sensing observations in the inner/outer corona, and in-situ observations further away, e.g. at 1 AU. Taking all these factors together, turned out to be a major obstacle in our understanding and characterizing of the 3D structure and evolution of CMEs. The situation improved dramatically with the availability of multi-viewpoint imaging observations of CMEs, all way through from the Sun to 1 AU, from the STEREO mission since 2006, combined with observations from other missions (SOHO, Hinode, SDO, IRIS). With this talk we will discuss several key recent results in CME science resulting from the analysis of multi-viewpoint observations. This includes: (1) shape and structure; (2) kinematics and energetics; (3) trajectories, deflections and rotations; (4) arrival times and velocities at 1 AU; (5) magnetic field structure; (6) relationships with coronal and interplanetary shocks and solar energetic particles. The implications of these results in terms of CME theories and models will be also addressed. We will conclude with a discussion of important open issues in our understanding of CMEs and how these could be addressed with upcoming (Solar Orbiter, Solar Probe Plus) and under-study missions (e.g., L5).

  10. Swift X-ray monitoring of M dwarf coronal variability

    Science.gov (United States)

    Miller, Brendan P.; Hagen, Cedric; Gallo, Elena; Wright, Jason

    2017-01-01

    We present new Swift observations of two M dwarfs with known exoplanets: GJ 15A and GJ 674. GJ 15A b is around 5.3 Earth masses with an 11.4 day orbital period, while GJ 674 is around 11.1 Earth masses with a 4.7 day orbital period. GJ 15A was observed several times in late 2014 and then monitored at approximately weekly intervals for several months in early 2016, for a total exposure of 18 ks. GJ 674 was monitored at approximately weekly intervals for most of 2016, for a total exposure of 40 ks. We provide light curves and hardness ratios for both sources, and also compare to earlier archival X-ray data. Both sources show significant X-ray variability, including between consecutive observations. We quantify the energy distribution for coronal flaring, and compare to optical results for M dwarfs from Kepler. Finally, we discuss the implications of M dwarf coronal activity for exoplanets orbiting within the nominal habitable zone.

  11. ON THE OBSERVATION AND SIMULATION OF SOLAR CORONAL TWIN JETS

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiajia; Wang, Yuming; Zhang, Quanhao [CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China, NO. 96, Jinzhai Road, Hefei, Anhui 230026 (China); Fang, Fang [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, 1234 Innovation Drive, Boulder, CO 80303 (United States); McIntosh, Scott W.; Fan, Yuhong [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

    2016-02-01

    We present the first observation, analysis, and modeling of solar coronal twin jets, which occurred after a preceding jet. Detailed analysis on the kinetics of the preceding jet reveals its blowout-jet nature, which resembles the one studied in Liu et al. However, the erupting process and kinetics of the twin jets appear to be different from the preceding one. Lacking detailed information on the magnetic fields in the twin jet region, we instead use a numerical simulation using a three-dimensional (3D) MHD model as described in Fang et al., and find that in the simulation a pair of twin jets form due to reconnection between the ambient open fields and a highly twisted sigmoidal magnetic flux, which is the outcome of the further evolution of the magnetic fields following the preceding blowout jet. Based on the similarity between the synthesized and observed emission, we propose this mechanism as a possible explanation for the observed twin jets. Combining our observation and simulation, we suggest that with continuous energy transport from the subsurface convection zone into the corona, solar coronal twin jets could be generated in the same fashion addressed above.

  12. AN MHD AVALANCHE IN A MULTI-THREADED CORONAL LOOP

    Energy Technology Data Exchange (ETDEWEB)

    Hood, A. W.; Cargill, P. J.; Tam, K. V. [School of Mathematics and Statistics, University of St Andrews, St Andrews, Fife, KY16 9SS (United Kingdom); Browning, P. K., E-mail: awh@st-andrews.ac.uk [School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester, M13 9PL (United Kingdom)

    2016-01-20

    For the first time, we demonstrate how an MHD avalanche might occur in a multithreaded coronal loop. Considering 23 non-potential magnetic threads within a loop, we use 3D MHD simulations to show that only one thread needs to be unstable in order to start an avalanche even when the others are below marginal stability. This has significant implications for coronal heating in that it provides for energy dissipation with a trigger mechanism. The instability of the unstable thread follows the evolution determined in many earlier investigations. However, once one stable thread is disrupted, it coalesces with a neighboring thread and this process disrupts other nearby threads. Coalescence with these disrupted threads then occurs leading to the disruption of yet more threads as the avalanche develops. Magnetic energy is released in discrete bursts as the surrounding stable threads are disrupted. The volume integrated heating, as a function of time, shows short spikes suggesting that the temporal form of the heating is more like that of nanoflares than of constant heating.

  13. Detection of thermal radio emission from a single coronal giant

    CERN Document Server

    O'Gorman, Eamon; Vlemmings, Wouter

    2016-01-01

    We report the detection of thermal continuum radio emission from the K0 III coronal giant Pollux ($\\beta$ Gem) with the Karl G. Jansky Very Large Array (VLA). The star was detected at 21 and 9 GHz with flux density values of $150\\pm21$ and $43\\pm8\\,\\mu$Jy, respectively. We also place a $3\\sigma_{\\mathrm{rms}}$ upper limit of $23\\,\\mu$Jy for the flux density at 3 GHz. We find the stellar disk-averaged brightness temperatures to be approximately 9500, 15000, and $<71000\\,$K, at 21, 9, and 3 GHz, respectively, which are consistent with the values of the quiet Sun. The emission is most likely dominated by optically thick thermal emission from an upper chromosphere at 21 and 9 GHz. We discuss other possible additional sources of emission at all frequencies and show that there may also be a small contribution from gyroresonance emission above active regions, coronal free-free emission and free-free emission from an optically thin stellar wind, particularly at the lower frequencies. We constrain the maximum mass-...

  14. A Type II Radio Burst without a Coronal Mass Ejection

    CERN Document Server

    Su, W; Ding, M D; Chen, P F; Sun, J Q

    2015-01-01

    Type II radio bursts are thought to be a signature of coronal shocks. In this paper, we analyze a short-lived type II burst that started at 07:40 UT on 2011 February 28. By carefully checking white-light images, we find that the type II radio burst is not accompanied by a coronal mass ejection, only with a C2.4 class flare and narrow jet. However, in the extreme-ultraviolet (EUV) images provided by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO), we find a wave-like structure that propagated at a speed of $\\sim$ 600 km s$^{-1}$ during the burst. The relationship between the type II radio burst and the wave-like structure is in particular explored. For this purpose, we first derive the density distribution under the wave by the differential emission measure (DEM) method, which is used to restrict the empirical density model. We then use the restricted density model to invert the speed of the shock that produces the observed frequency drift rate in the dynamic spectrum. The ...

  15. Decay-less kink oscillations in coronal loops

    Science.gov (United States)

    Anfinogentov, S.; Nisticò, G.; Nakariakov, V. M.

    2013-12-01

    Context. Kink oscillations of coronal loops in an off-limb active region are detected with the Imaging Assembly Array (AIA) instruments of the Solar Dynamics Observatory (SDO) at 171 Å. Aims: We aim to measure periods and amplitudes of kink oscillations of different loops and to determinate the evolution of the oscillation phase along the oscillating loop. Methods: Oscillating coronal loops were visually identified in the field of view of SDO/AIA and STEREO/EUVI-A: the loop length was derived by three-dimensional analysis. Several slits were taken along the loops to assemble time-distance maps. We identified oscillatory patterns and retrieved periods and amplitudes of the oscillations. We applied the cross-correlation technique to estimate the phase shift between oscillations at different segments of oscillating loops. Results: We found that all analysed loops show low-amplitude undamped transverse oscillations. Oscillation periods of loops in the same active region range from 2.5 to 11 min, and are different for different loops. The displacement amplitude is lower than 1 Mm. The oscillation phase is constant along each analysed loop. The spatial structure of the phase of the oscillations corresponds to the fundamental standing kink mode. We conclude that the observed behaviour is consistent with the empirical model in terms of a damped harmonic resonator affected by a non-resonant continuously operating external force. A movie is available in electronic form at http://www.aanda.org

  16. Posterior coronal plating for tibial fractures: technique and advantages

    Directory of Open Access Journals (Sweden)

    Montu Jain

    2014-04-01

    Full Text Available Objective:Tibial shaft fractures are straightforward to treat but when associated with soft tissue injury particularly at the nail entry/plate insertion site or there is significant comminution proximally or a large butterfly fragment/a second split component in the posterior coronal plane, it is a challenge to the treating surgeon. The aim of the present report is to describe the technique of posterior coronal plating in such a scenario and its advantages. Methods:Between July 2008 and June 2011, 12 patients were pro spectively treated by this approach using 4.5 mm broad dynamic compression plates. Results:The time of bony consolidation and full weight bearing averaged 21.7 weeks (range, 16-26 weeks. Patients were followed up for at least 24 months (range, 24-48 months. At 1 year postoper atively, no loss in reduction or alignment was observed. Mean Hospital for Lower Extremity Measurement Functional Score was 72.8 (range, 64-78. All patients were satisfied with their treatment outcomes. Conclusion:Direct posterior approach and fixation using prone position helps to visualise the fracture fragments and provide rigid fixation. The approach is simple and extensile easily, apart from advantages of less soft tissue and hardware problems compared to standard medial or lateral plating. Key words: Tibial fractures; Bone plates; Orthopedic procedures

  17. Soft X-ray emission in flaring coronal loops

    CERN Document Server

    Pinto, R F; Brun, A S

    2014-01-01

    Solar flares are associated with intense soft X-ray emission generated by the hot flaring plasma in coronal magnetic loops. Kink unstable twisted flux-ropes provide a source of magnetic energy which can be released impulsively and account for the heating of the plasma in flares. We investigate the temporal, spectral and spatial evolution of the properties of the thermal X-ray emission produced in such kink-unstable magnetic flux-ropes using a series of MHD simulations. We deduce emission diagnostics and their temporal evolution and discuss the results of the simulations with respect to observations. The numerical setup used consists of a highly twisted loop embedded in a region of uniform and untwisted background coronal magnetic field. We let the kink instability develop, compute the evolution of the plasma properties in the loop (density, temperature) and deduce the X-ray emission properties of the plasma during the whole flaring episode. During the initial phase of the instability plasma heating is mostly ...

  18. CONVERGING SUPERGRANULAR FLOWS AND THE FORMATION OF CORONAL PLUMES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.-M.; Warren, H. P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Muglach, K., E-mail: yi.wang@nrl.navy.mil, E-mail: harry.warren@nrl.navy.mil, E-mail: karin.muglach@nasa.gov [Code 674, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2016-02-20

    Earlier studies have suggested that coronal plumes are energized by magnetic reconnection between unipolar flux concentrations and nearby bipoles, even though magnetograms sometimes show very little minority-polarity flux near the footpoints of plumes. Here we use high-resolution extreme-ultraviolet (EUV) images and magnetograms from the Solar Dynamics Observatory (SDO) to clarify the relationship between plume emission and the underlying photospheric field. We find that plumes form where unipolar network elements inside coronal holes converge to form dense clumps, and fade as the clumps disperse again. The converging flows also carry internetwork fields of both polarities. Although the minority-polarity flux is sometimes barely visible in the magnetograms, the corresponding EUV images almost invariably show loop-like features in the core of the plumes, with the fine structure changing on timescales of minutes or less. We conclude that the SDO observations are consistent with a model in which plume emission originates from interchange reconnection in converging flows, with the plume lifetime being determined by the ∼1 day evolutionary timescale of the supergranular network. Furthermore, the presence of large EUV bright points and/or ephemeral regions is not a necessary precondition for the formation of plumes, which can be energized even by the weak, mixed-polarity internetwork fields swept up by converging flows.

  19. The role of torsional Alfven waves in coronal heating

    CERN Document Server

    Antolin, P

    2009-01-01

    In the context of coronal heating, among the zoo of MHD waves that exist in the solar atmosphere, Alfven waves receive special attention. Indeed, these waves constitute an attractive heating agent due to their ability to carry over the many different layers of the solar atmosphere sufficient energy to heat and maintain a corona. However, due to their incompressible nature these waves need a mechanism such as mode conversion (leading to shock heating), phase mixing, resonant absorption or turbulent cascade in order to heat the plasma. New observations with polarimetric, spectroscopic and imaging instruments such as those on board of the japanese satellite Hinode, or the SST or CoMP, are bringing strong evidence for the existence of energetic Alfven waves in the solar corona. In order to assess the role of Alfven waves in coronal heating, in this work we model a magnetic flux tube being subject to Alfven wave heating through the mode conversion mechanism. Using a 1.5-dimensional MHD code we carry out a paramete...

  20. Automated Coronal Loop Identification Using Digital Image Processing Techniques

    Science.gov (United States)

    Lee, Jong K.; Gary, G. Allen; Newman, Timothy S.

    2003-01-01

    The results of a master thesis project on a study of computer algorithms for automatic identification of optical-thin, 3-dimensional solar coronal loop centers from extreme ultraviolet and X-ray 2-dimensional images will be presented. These center splines are proxies of associated magnetic field lines. The project is pattern recognition problems in which there are no unique shapes or edges and in which photon and detector noise heavily influence the images. The study explores extraction techniques using: (1) linear feature recognition of local patterns (related to the inertia-tensor concept), (2) parametric space via the Hough transform, and (3) topological adaptive contours (snakes) that constrains curvature and continuity as possible candidates for digital loop detection schemes. We have developed synthesized images for the coronal loops to test the various loop identification algorithms. Since the topology of these solar features is dominated by the magnetic field structure, a first-order magnetic field approximation using multiple dipoles provides a priori information in the identification process. Results from both synthesized and solar images will be presented.

  1. Development of a tunable filter for coronal polarimetry

    Science.gov (United States)

    Tomczyk, S.; Mathew, S. K.; Gallagher, D.

    2016-07-01

    Measuring magnetic fields in the solar corona is crucial to understanding and predicting the Sun's generation of space weather that affects communications, GPS systems, space flight, and power transmission. The Coronal Solar Magnetism Observatory Large Coronagraph (COSMO LC) is a proposed 1.5 m aperture coronagraph designed to synoptically observe magnetic fields and plasma properties in the large-scale corona to improve our understanding of solar processes that cause space weather. The LC will observe coronal emission lines over the wavelength range from 500 to 1100 nm with a field of view of 1° and a spatial resolution of 2 arcsec. A spectral resolution greater than 8000 over the wavelength range is needed to resolve the polarization signatures of magnetic fields in the emission line profiles. The aperture and field of view of the LC set an étendue requirement of 1.39 m2 deg2 for the postfocus instrumentation. We find that a tunable wide-field birefringent filter using Lithium Niobate crystals can meet the étendue and spectral resolution requirements for the LC spectrometer. We have tested a number of commercially available crystals and verify that crystals of the required size and birefringence uniformity are available. We also evaluate electro-optical tuning of a Lithium Niobate birefringent filter by the application of high voltage. This tunable filter represents a key enabling technology for the COSMO LC.

  2. High-spatial-resolution microwave and related observations as diagnostics of coronal loops

    Science.gov (United States)

    Holman, Gordon D.

    1986-01-01

    High spatial resolution microwave observations of coronal loops, together with theoretical models for the loop emission, can provide detailed information about the temperature, density, and magnetic field within the loop, as well as the environment around the loop. The capability for studying magnetic fields is particularly important, since there is no comparable method for obtaining direct information about coronal magnetic fields. Knowledge of the magnetic field strength and structure in coronal loops is important for understanding both coronal heating and flares. With arc-second-resolution microwave observations from the Very Large Array (VLA), supplemental high-spectral-resolution microwave data from a facility such as the Owens Valley frequency-agile interferometer, and the ability to obtain second-of-arc resolution EUV aor soft X ray images, the capability already exists for obtaining much more detailed information about coronal plasma and magnetic structures than is presently available. This capability is discussed.

  3. Decay of Activity Complexes, Formation of Unipolar Magnetic Regions and Coronal Holes in their Causal Relation

    CERN Document Server

    Golubeva, Elena

    2016-01-01

    North-south asymmetry of sunspot activity resulted in an asynchronous reversal of the Sun's polar fields in the current cycle. The asymmetry is also observed in the formation of polar coronal holes. A stable coronal hole was first formed at the South Pole, despite the later polar-field reversal there. The aim of this study is to understand processes making this situation possible. Synoptic magnetic maps from the Global Oscillation Network Group and corresponding coronal-hole maps from the Extreme ultraviolet Imaging Telescope aboard the Solar and Heliospheric Observatory and the Atmospheric Imaging Assembly aboard the Solar Dynamics Observatory are analyzed here to study a causal relationship between the decay of activity complexes, evolution of large-scale magnetic fields, and formation of coronal holes. Ensembles of coronal holes associated with decaying active regions and activity complexes are presented. These ensembles take part in global rearrangements of the Sun's open magnetic flux. In particular, the...

  4. Coronal Holes and Open Magnetic Flux over Cycles 23 and 24

    Science.gov (United States)

    Lowder, Chris; Qiu, Jiong; Leamon, Robert

    2017-01-01

    As the observational signature of the footprints of solar magnetic field lines open into the heliosphere, coronal holes provide a critical measure of the structure and evolution of these lines. Using a combination of Solar and Heliospheric Observatory/Extreme ultraviolet Imaging Telescope (SOHO/EIT), Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), and Solar Terrestrial Relations Observatory/Extreme Ultraviolet Imager (STEREO/EUVI A/B) extreme ultraviolet (EUV) observations spanning 1996 - 2015 (nearly two solar cycles), coronal holes are automatically detected and characterized. Coronal hole area distributions show distinct behavior in latitude, defining the domain of polar and low-latitude coronal holes. The northern and southern polar regions show a clear asymmetry, with a lag between hemispheres in the appearance and disappearance of polar coronal holes.

  5. Effect of coronal temperature on the scale of solar chromospheric jets

    CERN Document Server

    Iijima, H

    2015-01-01

    We investigate the effect of coronal temperature on the formation process of solar chromospheric jets using two-dimensional magnetohydrodynamic simulations of the region from the upper convection zone to the lower corona. We develop a new radiative magnetohydrodynamic code for the dynamic modeling of the solar atmosphere, employing a LTE equation of state, optically thick radiative loss in the photosphere, optically thin radiative loss in the chromosphere and the corona, and thermal conduction along the magnetic field lines. Many chromospheric jets are produced in the simulations by shock waves passing through the transition region. We find that these jets are projected farther outward when the coronal temperature is lower (similar to that in coronal holes) and shorter when the coronal temperature is higher (similar to that in active regions). When the coronal temperature is high, the deceleration of the chromospheric jets is consistent with the model in which deceleration is determined by the periodic chromo...

  6. Spectral Characteristics of Large-Scale Radio Emission Areas in Coronal Holes

    CERN Document Server

    Prosovetsky, D V; Kochanov, A A

    2013-01-01

    The spectra of the coronal hole radio emission in solar cycles 23 and 24 have been studied based on RATAN-600 data in the 4-16.5 GHz range at frequencies of 5.7 and 17 GHz and 327 MHz. It has been found that bright features of coronal hole microwave emission at 17 GHz and dark features at 5.7 GHz can exist in coronal holes when the spectral index is 1.25-1.5 in the 6.5-16.5 GHz range; the radio spectrum in this range is flat when coronal holes are indiscernible against the background of a quiet Sun. The possible vertical scale of the solar atmosphere over coronal holes is discussed.

  7. Unresolved Fine-scale Structure in Solar Coronal Loop-tops

    Science.gov (United States)

    Scullion, E.; Rouppe van der Voort, L.; Wedemeyer, S.; Antolin, P.

    2014-12-01

    New and advanced space-based observing facilities continue to lower the resolution limit and detect solar coronal loops in greater detail. We continue to discover even finer substructures within coronal loop cross-sections, in order to understand the nature of the solar corona. Here, we push this lower limit further to search for the finest coronal loop substructures, through taking advantage of the resolving power of the Swedish 1 m Solar Telescope/CRisp Imaging Spectro-Polarimeter (CRISP), together with co-observations from the Solar Dynamics Observatory/Atmospheric Image Assembly (AIA). High-resolution imaging of the chromospheric Hα 656.28 nm spectral line core and wings can, under certain circumstances, allow one to deduce the topology of the local magnetic environment of the solar atmosphere where its observed. Here, we study post-flare coronal loops, which become filled with evaporated chromosphere that rapidly condenses into chromospheric clumps of plasma (detectable in Hα) known as a coronal rain, to investigate their fine-scale structure. We identify, through analysis of three data sets, large-scale catastrophic cooling in coronal loop-tops and the existence of multi-thermal, multi-stranded substructures. Many cool strands even extend fully intact from loop-top to footpoint. We discover that coronal loop fine-scale strands can appear bunched with as many as eight parallel strands within an AIA coronal loop cross-section. The strand number density versus cross-sectional width distribution, as detected by CRISP within AIA-defined coronal loops, most likely peaks at well below 100 km, and currently, 69% of the substructure strands are statistically unresolved in AIA coronal loops.

  8. Estudios de ingresos municipales: Bolivia

    OpenAIRE

    José Antonio Teran C.

    2007-01-01

    El estudio abarca tres ámbitos de evaluación y recomendaciones: i) el marco normativo que establece las políticas para las administraciones tributarias municipales; ii) las capacidades de estas administraciones y las condiciones de oferta y demanda de servicios de asistencia para su fortalecimiento; y iii) la evaluación cuantitativa de los ingresos propios municipales, el establecimiento de categorías y las políticas que podrían implementarse a partir de esta información.

  9. LOS ESTUDIOS DE POBREZA URBANA

    Directory of Open Access Journals (Sweden)

    Rina De León Herrera

    2007-08-01

    Full Text Available En este artículo se intenta mostrar en forma sucinta la evolución de los estudios de pobreza urbana; se retoma para ello la producción escritural de investigadores que han hecho aportes valiosos sobre la temática en diferentes épocas y espacios geográficos. La información se ha organizado en dos unidades de análisis: la producción escritural en los países desarrollados y en los países en desarrollo.

  10. An estimate of the coronal magnetic field near a solar coronal mass ejection from low-frequency radio observations

    Energy Technology Data Exchange (ETDEWEB)

    Hariharan, K.; Ramesh, R.; Kishore, P.; Kathiravan, C. [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034 (India); Gopalswamy, N., E-mail: khariharan@iiap.res.in [Solar Physics Laboratory, NASA/GSFC, Code 671, Greenbelt, MD (United States)

    2014-11-01

    We report ground-based, low-frequency (<100 MHz) radio imaging, spectral, and polarimeter observations of the type II radio burst associated with the solar coronal mass ejection (CME) that occurred on 2013 May 2. The spectral observations indicate that the burst has fundamental (F) and harmonic (H) emission components with split-band and herringbone structures. The imaging observations at 80 MHz indicate that the H component of the burst was located close to leading edge of the CME at a radial distance of r ≈ 2 R {sub ☉} in the solar atmosphere. The polarimeter observations of the type II burst, also at 80 MHz, indicate that the peak degree of circular polarization (dcp) corresponding to the emission generated in the corona ahead of and behind the associated MHD shock front are ≈0.05 ± 0.02 and ≈0.1 ± 0.01, respectively. We calculated the magnetic field B in the above two coronal regions by adopting the empirical relationship between the dcp and B for the harmonic plasma emission and the values are ≈(0.7-1.4) ± 0.2 G and ≈(1.4-2.8) ± 0.1 G, respectively.

  11. Tratamiento del maxilar posterior atrófico mediante técnica de reconstrucción tridimensional con elevación de seno y abordaje «en tunel»

    Directory of Open Access Journals (Sweden)

    Andrés Restoy

    2015-01-01

    Conclusiones: El tratamiento del sector posterior maxilar atrófico mediante reconstrucción tridimensional con autoinjerto óseo, elevación sinusal y abordaje por tunelización es una técnica que proporciona resultados predecibles y estables, permitiendo la rehabilitación con coronas sobre implantes dentales de dimensiones adecuadas.

  12. Coronal magnetic fields from multiple type II bursts

    Science.gov (United States)

    Honnappa, Vijayakumar; Raveesha, K. H.; Subramanian, K. R.

    Coronal magnetic fields from multiple type II bursts Vijayakumar H Doddamani1*, Raveesha K H2 and Subramanian3 1Bangalore University, Bangalore, Karnataka state, India 2CMR Institute of Technology, Bangalore, Karnataka state, India 3 Retd, Indian Institute of Astrophysics, Bangalore, Karnataka state, India Abstract Magnetic fields play an important role in the astrophysical processes occurring in solar corona. In the solar atmosphere, magnetic field interacts with the plasma, producing abundant eruptive activities. They are considered to be the main factors for coronal heating, particle acceleration and the formation of structures like prominences, flares and Coronal Mass Ejections. The magnetic field in solar atmosphere in the range of 1.1-3 Rsun is especially important as an interface between the photospheric magnetic field and the solar wind. Its structure and time dependent change affects space weather by modifying solar wind conditions, Cho (2000). Type II doublet bursts can be used for the estimation of the strength of the magnetic field at two different heights. Two type II bursts occur sometimes in sequence. By relating the speed of the type II radio burst to Alfven Mach Number, the Alfven speed of the shock wave generating type II radio burst can be calculated. Using the relation between the Alfven speed and the mean frequency of emission, the magnetic field strength can be determined at a particular height. We have used the relative bandwidth and drift rate properties of multiple type II radio bursts to derive magnetic field strengths at two different heights and also the gradient of the magnetic field in the outer corona. The magnetic field strength has been derived for different density factors. It varied from 1.2 to 2.5 gauss at a solar height of 1.4 Rsun. The empirical relation of the variation of the magnetic field with height is found to be of the form B(R) = In the present case the power law index ‘γ’ varied from -3 to -2 for variation of

  13. An observationally-driven kinetic approach to coronal heating

    Science.gov (United States)

    Moraitis, K.; Toutountzi, A.; Isliker, H.; Georgoulis, M.; Vlahos, L.; Chintzoglou, G.

    2016-11-01

    Aims: Coronal heating through the explosive release of magnetic energy remains an open problem in solar physics. Recent hydrodynamical models attempt an investigation by placing swarms of "nanoflares" at random sites and times in modeled one-dimensional coronal loops. We investigate the problem in three dimensions, using extrapolated coronal magnetic fields of observed solar active regions. Methods: We applied a nonlinear force-free field extrapolation above an observed photospheric magnetogram of NOAA active region (AR) 11 158. We then determined the locations, energy contents, and volumes of "unstable" areas, namely areas prone to releasing magnetic energy due to locally accumulated electric current density. Statistical distributions of these volumes and their fractal dimension are inferred, investigating also their dependence on spatial resolution. Further adopting a simple resistivity model, we inferred the properties of the fractally distributed electric fields in these volumes. Next, we monitored the evolution of 105 particles (electrons and ions) obeying an initial Maxwellian distribution with a temperature of 10 eV, by following their trajectories and energization when subjected to the resulting electric fields. For computational convenience, the length element of the magnetic-field extrapolation is 1 arcsec, or 725 km, much coarser than the particles' collisional mean free path in the low corona (0.1-1 km). Results: The presence of collisions traps the bulk of the plasma around the unstable volumes, or current sheets (UCS), with only a tail of the distribution gaining substantial energy. Assuming that the distance between UCS is similar to the collisional mean free path we find that the low active-region corona is heated to 100-200 eV, corresponding to temperatures exceeding 2 MK, within tens of seconds for electrons and thousands of seconds for ions. Conclusions: Fractally distributed, nanoflare-triggening fragmented UCS in the active-region corona can

  14. El cuidado de la persona con cáncer: Un abordaje psicosocial The care of cancer patients: A psychosocial approach

    Directory of Open Access Journals (Sweden)

    Sílvia Regina Secoli

    2005-03-01

    Full Text Available En las últimas décadas, los avances tecnológicos en el área del cáncer permitieron que la prevención y los nuevos tratamientos favorezcan el aumento de las tasas de sobrevivencia de los pacientes y la mejoría en la calidad de su vida. En ese sentido, las investigaciones evidencian la necesidad de trascender de un modelo biomédico de atención a la salud, hacia un abordaje psicosocial. El objetivo del presente artículo es contribuir con reflexiones respecto a la temática y presentar una propuesta con este abordaje, como un instrumento de intervención de enfermería capaz de considerar la singularidad del sujeto con cáncer y su familia, en el modo de vivenciar sus experiencias, y los impactos que el cáncer provoca en la vida psíquica y social.In the last decades, the technological improvements on cancer field allowed the increasement of the patients’ survival rates and quality of life through prevention and new treatments. In this manner, the researches have made evident the necessity of transcending the biomedical model of attention to health into a psychosocial approach. So, the goal of the present article will be to contribute with the reflections about this subject and to bring a proposal of a psychosocial approach, as an instrument of intervention in nurse assistance, capable of considering the cancer patients and their families, their uniqueness way of living their experiences, regarding the impacts caused by cancer in their psychic and social life.

  15. Modified semilunar coronally advanced flap: A case series.

    Science.gov (United States)

    Pai, B S Jagadish; Rajan, Smitha Anitha; Padma, R; Suragimath, Girish; Annaji, Shridhar; Kamath, K Vinesh

    2013-01-01

    Dentists traditionally think of periodontal treatment as a means of saving the teeth while leaving the patient with an esthetic problem. The goal of gingival esthetics is to maintain normal healthy gingival appearance around teeth that must be restored. Gingival recession represents a significant concern for patients and a therapeutic problem for the clinician. Root coverage is the goal of periodontal plastic surgery when treating gingival recessions in the esthetic zone. Correction of mucogingival recession deformities with a variety of periodontal plastic surgical procedures have been described each demonstrating a variable degree of success. This case report presents to you the treatment outcomes and predictability of modified semilunar coronally advanced flap (Kamran Haghighat) techniques described for the treatment of recession defects on single and multiple adjacent teeth, respectively.

  16. Stellar winds, dead zones, and coronal mass ejections

    CERN Document Server

    Keppens, R

    1999-01-01

    Axisymmetric stellar wind solutions are presented, obtained by numerically solving the ideal magnetohydrodynamic (MHD) equations. Stationary solutions are critically analysed using the knowledge of the flux functions. These flux functions enter in the general variational principle governing all axisymmetric stationary ideal MHD equilibria. The magnetized wind solutions for (differentially) rotating stars contain both a `wind' and a `dead' zone. We illustrate the influence of the magnetic field topology on the wind acceleration pattern, by varying the coronal field strength and the extent of the dead zone. This is evident from the resulting variations in the location and appearance of the critical curves where the wind speed equals the slow, Alfven, and fast speed. Larger dead zones cause effective, fairly isotropic acceleration to super-Alfvenic velocities as the polar, open field lines are forced to fan out rapidly with radial distance. A higher field strength moves the Alfven transition outwards. In the ecl...

  17. An ice-cream cone model for coronal mass ejections

    Science.gov (United States)

    Xue, X. H.; Wang, C. B.; Dou, X. K.

    2005-08-01

    In this study, we use an ice-cream cone model to analyze the geometrical and kinematical properties of the coronal mass ejections (CMEs). Assuming that in the early phase CMEs propagate with near-constant speed and angular width, some useful properties of CMEs, namely the radial speed (v), the angular width (α), and the location at the heliosphere, can be obtained considering the geometrical shapes of a CME as an ice-cream cone. This model is improved by (1) using an ice-cream cone to show the near real configuration of a CME, (2) determining the radial speed via fitting the projected speeds calculated from the height-time relation in different azimuthal angles, (3) not only applying to halo CMEs but also applying to nonhalo CMEs.

  18. Alfven Wave Solar Model: Part 1, Coronal Heating

    CERN Document Server

    van der Holst, Bart; Meng, Xing; Jin, Meng; Manchester, Ward B; Toth, Gabor; Gombosi, Tamas I

    2013-01-01

    We present the new Alfven Wave Solar Model (AWSoM), a global model from the upper chromosphere to the corona and the heliosphere. The coronal heating and solar wind acceleration are addressed with low-frequency Alfven wave turbulence. The injection of Alfven wave energy at the inner boundary is such that the Poynting flux is proportional to the magnetic field strength. The three-dimensional magnetic field topology is simulated using data from photospheric magnetic field measurements. This model does not impose open-closed magnetic field boundaries; those develop self-consistently. The physics includes: (1) The model employs three different temperatures, namely the isotropic electron temperature and the parallel and perpendicular ion temperatures. The firehose, mirror, and ion-cyclotron instabilities due to the developing ion temperature anisotropy are accounted for. (2) The Alfven waves are partially reflected by the Alfven speed gradient and the vorticity along the field lines. The resulting counter-propagat...

  19. Numerical simulations of transverse oscillations in radiatively cooling coronal loops

    CERN Document Server

    Magyar, N; Marcu, A

    2015-01-01

    We aim to study the influence of radiative cooling on the standing kink oscillations of a coronal loop. Using the FLASH code, we solved the 3D ideal magnetohydrodynamic equations. Our model consists of a straight, density enhanced and gravitationally stratified magnetic flux tube. We perturbed the system initially, leading to a transverse oscillation of the structure, and followed its evolution for a number of periods. A realistic radiative cooling is implemented. Results are compared to available analytical theory. We find that in the linear regime (i.e. low amplitude perturbation and slow cooling) the obtained period and damping time are in good agreement with theory. The cooling leads to an amplification of the oscillation amplitude. However, the difference between the cooling and non-cooling cases is small (around 6% after 6 oscillations). In high amplitude runs with realistic cooling, instabilities deform the loop, leading to increased damping. In this case, the difference between cooling and non-cooling...

  20. Magnetohydrodynamic turbulent cascade of coronal loop magnetic fields.

    Science.gov (United States)

    Rappazzo, A F; Velli, M

    2011-06-01

    The Parker model for coronal heating is investigated through a high resolution simulation. An inertial range is resolved where fluctuating magnetic energy EMk[Please see symbol]) [Please see symbol] k[Please see symbol](-2.7) exceeds kinetic energy EK(k[Please see symbol])[Please see symbol]k[Please see symbol](-0.6). Increments scale as δbℓ ~/= ℓ(-0.85) and δuℓ ~/= ℓ(+0.2) with velocity increasing at small scales, indicating that magnetic reconnection plays a prime role in this turbulent system. We show that spectral energy transport is akin to standard magnetohydrodynamic (MHD) turbulence even for a system of reconnecting current sheets sustained by the boundary. In this new MHD turbulent cascade, kinetic energy flows are negligible while cross-field flows are enhanced, and through a series of "reflections" between the two fields, cascade more than half of the total spectral energy flow.

  1. Nonunion of coronal shear fracture of femoral condyle

    Directory of Open Access Journals (Sweden)

    Singh Ajay Pal

    2011-06-01

    Full Text Available 【Abstract】Isolated coronal fractures of femoral condyle are rare in adults and nonunion of Hoffa fracture is reported only a few times in the literature. We analyzed six cases of nonunion of Hoffa fractures over a period of three years. Three patients were treated conservatively and three patients had fixation failures. Delay of presentation was 2 months to one year. Treatment protocol consisted of open reduction, excision of pseudoarthrosis, bone grafting and internal fixation along with knee arthrolysis. Union was achieved in all patients at mean 16 weeks. The treatment of nonunion of Hoffa fractures requires careful preoperative planning and meticulous surgical technique. The literature regarding the controversies in fracture management and surgical technique are reviewed. Key words: Femoral fracture; Fracture fixation, internal; Retrospective studies

  2. Nonunion of coronal shear fracture of femoral condyle

    Institute of Scientific and Technical Information of China (English)

    Ajay Pal Singh; Ish Kumar Dhammi; Raju Vaishya; Anil Kumar Jain; Arun Pal Singh; Prashant Modi

    2011-01-01

    Isolated coronal fractures of femoral condyle are rare in adults and nonunion of Hoffa fracture is reported only a few times in the literature. We analyzed six cases of nonunion of Hoffa fractures over a period of three years. Three patients were treated conservatively and three patients had fixation failures. Delay of presentation was 2 months to one year. Treatment protocol consisted of open reduction, excision of pseudoarthrosis, bone grafting and internal fixation along with knee arthrolysis. Union was achieved in all patients at mean 16 weeks. The treatment of nonunion of Hoffa fractures requires careful preoperative planning and meticulous surgical technique. The literature regarding the controversies in fracture management and surgical technique are reviewed.

  3. Coronal Magnetic Flux Rope Equilibria and Magnetic Helicity

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using a 2.5-dimensional (2.5-D) ideal MHD model, this paper ana lyzes the equilibrium properties of coronal magnetic flux ropes in a bipolar ambient magnetic field. It is found that the geometrical features of the magnetic flux rope,including the height of the rope axis, the half-width of the rope, and the length of the vertical current sheet below the rope, are determined by a single magnetic parameter, the magnetic helicity, which is the sum of the self-helicity of the rope and the mutual helicity between the rope field and the ambient magnetic field. All the geometrical parameters increase monotonically with increasing magnetic helicity.The implication of this result in solar active phenomena is briefly discussed.

  4. MHD Remote Numerical Simulations: Evolution of Coronal Mass Ejections

    CERN Document Server

    Hernandez-Cervantes, L; Gonzalez-Ponce, A R

    2008-01-01

    Coronal mass ejections (CMEs) are solar eruptions into interplanetary space of as much as a few billion tons of plasma, with embedded magnetic fields from the Sun's corona. These perturbations play a very important role in solar--terrestrial relations, in particular in the spaceweather. In this work we present some preliminary results of the software development at the Universidad Nacional Autonoma de Mexico to perform Remote MHD Numerical Simulations. This is done to study the evolution of the CMEs in the interplanetary medium through a Web-based interface and the results are store into a database. The new astrophysical computational tool is called the Mexican Virtual Solar Observatory (MVSO) and is aimed to create theoretical models that may be helpful in the interpretation of observational solar data.

  5. Plasma Heating Suring a Coronal Mass Ejection Observed by SOHO

    CERN Document Server

    Murphy, N A; Korreck, K E

    2011-01-01

    We perform a time-dependent ionization analysis to constrain plasma heating requirements during a fast partial halo coronal mass ejection (CME) observed on 2000 June 28 by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory (SOHO). We use two methods to derive densities from the UVCS measurements, including a density sensitive O V line ratio at 1213.85 and 1218.35 Angstroms, and radiative pumping of the O VI 1032,1038 doublet by chromospheric emission lines. The most strongly constrained feature shows cumulative plasma heating comparable to or greater than the kinetic energy, while features observed earlier during the event show cumulative plasma heating comparable to or less than the kinetic energy. SOHO Michelson Doppler Imager (MDI) observations are used to estimate the active region magnetic energy. We consider candidate plasma heating mechanisms and provide constraints when possible. Because this CME was associated with a relatively weak flare, the contribution b...

  6. Einstein Observatory coronal temperatures of late-type stars

    Science.gov (United States)

    Schmitt, J. H. M. M.; Collura, A.; Sciortino, S.; Vaiana, G. S.; Harnden, F. R., Jr.

    1990-01-01

    The results are presented of a survey of the coronal temperatures of late-type stars using the Einstein Observatory IPC. The spectral analysis shows that the frequently found one- and two-temperature descriptions are mainly influenced by the SNR of the data and that models using continuous emission measure distributions can provide equally adequate and physically more meaningful and more plausible descriptions. Intrinsic differences in differential emission measure distributions are found for four groups of stars. M dwarfs generally show evidence for high-temperature gas in conjunction with lower-temperature material, while main-sequence stars of types F and G have the high-temperature component either absent or very weak. Very hot coronae without the lower-temperature component appearing in dwarf stars are evident in most of the giant stars studied. RS CVn systems show evidence for extremely hot coronae, sometimes with no accompanying lower-temperature material.

  7. Changes in the subgingival biofilm composition after coronally positioned flap

    Directory of Open Access Journals (Sweden)

    Jadson Almeida Lima

    2011-02-01

    Full Text Available OBJECTIVES: This study evaluated the effects of coronally positioned flap (CPF on the subgingival biofilm composition. MATERIAL AND METHODS: Twenty-two subjects with gingival recessions were treated with CPF. Clinical parameters were assessed before and at 6 months after surgery. Subgingival biofilms were analyzed by checkerboard DNA-DNA hybridization technique for 40 bacterial species. RESULTS: Recession height, clinical attachment level and bleeding on probing improved significantly (p<0.05 at 6 months post-CPF. The proportions of 10 periodontal pathogens and the proportions of red and orange complexes decreased at 6 months. CONCLUSION: In conclusion, CPF can induce beneficial effects on the composition of the subgingival microbiota after 6 months.

  8. The Kinematics and Morphology of Solar Coronal Mass Ejections

    CERN Document Server

    Byrne, Jason P

    2012-01-01

    Solar coronal mass ejections (CMEs) are large-scale eruptions of plasma and magnetic field from the Sun into the corona and interplanetary space. They are the most significant drivers of adverse space weather at Earth and other locations in the heliosphere, so it is important to understand the physics governing their eruption and propagation. However the diffuse morphology and transient nature of CMEs makes them difficult to identify and track using traditional image processing techniques. In this thesis the implementation of multiscale image processing techniques to identify and track the CME front through coronagraph images is detailed. An ellipse characterisation of the CME front is used to determine the CME kinematics and morphology with increased precision as compared to techniques used in current CME catalogues, and efforts are underway to automate this procedure for applying to a large number of CME observations for future analysis. It was found that CMEs do not simply undergo constant acceleration, bu...

  9. On interplanetary coronal mass ejection identification at 1 AU

    Science.gov (United States)

    Mulligan, T.; Russell, C. T.; Gosling, J. T.

    1999-06-01

    Coronal mass ejections are believed to be produced in the corona from closed magnetic regions not previously participating in the solar wind expansion. At 1 AU their interplanetary counterparts (ICMEs) generally have a number of distinct plasma and field signatures that distinguish them from the ambient solar wind. These include heat flux dropouts, bi-directional streaming, enhanced alpha particle events, times of depressed proton temperatures, intervals of distorted or enhanced magnetic field, and times of large magnetic field rotations characteristic of magnetic clouds. The first three of these signatures are phenomena that occur at some point within the ICME, but do not necessarily persist throughout the entire ICME. The large scale magnetic field rotations, distortions and enhancements, and the proton temperature depressions tend to mark more accurately the beginning and end of the ICME proper. We examine herein the reliability with which each of these markers identifies ICMEs utilizing ISEE-3 data from 1978-1980.

  10. Interplanetary Coronal Mass Ejections observed by MESSENGER and Venus Express

    CERN Document Server

    Good, S W

    2015-01-01

    Interplanetary coronal mass ejections (ICMEs) observed by the MESSENGER (MES) and Venus Express (VEX) spacecraft have been catalogued and analysed. The ICMEs were identified by a relatively smooth rotation of the magnetic field direction consistent with a flux rope structure, coinciding with a relatively enhanced magnetic field strength. A total of 35 ICMEs were found in the surveyed MES data (primarily from March 2007 to April 2012), and 84 ICMEs in the surveyed VEX data (from May 2006 to December 2013). The ICME flux rope configurations have been determined. Ropes with northward leading edges were about four times more common than ropes with southward leading edges, in agreement with a previously established solar cycle dependence. Ropes with low inclinations to the solar equatorial plane were about four times more common than ropes with high inclinations, possibly an observational effect. Left and right-handed ropes were observed in almost equal numbers. In addition, data from MES, VEX, STEREO-A, STEREO-B ...

  11. Geoeffectiveness of Coronal Mass Ejections in the SOHO era

    CERN Document Server

    Dumbovic, Mateja; Vrsnak, Bojan; Sudar, Davor; Rodriguez, Luciano; Ruzdjak, Domagoj; Leer, Kristoffer; Vennerstrom, Susanne; Veronig, Astrid

    2014-01-01

    The main objective of the study is to determine the probability distributions of the geomagnetic Dst index as a function of the coronal mass ejection (CME) and solar flare parameters for the purpose of establishing a probabilistic forecast tool for the geomagnetic storm intensity. Several CME and flare parameters as well as the effect of successive-CME occurrence in changing the probability for a certain range of Dst index values, were examined. The results confirm some of already known relationships between remotely-observed properties of solar eruptive events and geomagnetic storms, namely the importance of initial CME speed, apparent width, source position, and the associated solar flare class. In this paper we quantify these relationships in a form to be used for space weather forecasting in future. The results of the statistical study are employed to construct an empirical statistical model for predicting the probability of the geomagnetic storm intensity based on remote solar observations of CMEs and fl...

  12. An Ab Initio approach to Solar Coronal Loops

    CERN Document Server

    Gudiksen, B V

    2004-01-01

    Data from recent numerical simulations of the solar corona and transition region are analysed and the magnetic field connection between the low corona and the photosphere is found to be close to that of a potential field. The fieldline to fieldline displacements follow a power law distribution with typical displacements of just a few Mm. Three loops visible in emulated Transition Region And Coronal Explorer (TRACE) filters are analysed in detail and found to have significantly different heating rates and distributions thereof, one of them showing a small scale heating event. The dynamical structure is complicated even though all the loops are visible in a single filter along most of their lengths. None of the loops are static, but are in the process of evolving into loops with very different characteristics. Differential Emission Measure (DEM) curves along one of the loops illustrate that DEM curves have to be treated carefully if physical characteristics are to be extracted.

  13. On Sun-to-Earth Propagation of Coronal Mass Ejections

    CERN Document Server

    Liu, Ying D; Lugaz, Noé; Möstl, Christian; Davies, Jackie A; Bale, Stuart D; Lin, Robert P

    2013-01-01

    We investigate how coronal mass ejections (CMEs) propagate through, and interact with, the inner heliosphere between the Sun and Earth, a key question in CME research and space weather forecasting. CME Sun-to-Earth kinematics are constrained by combining wide-angle heliospheric imaging observations, interplanetary radio type II bursts and in situ measurements from multiple vantage points. We select three events for this study, the 2012 January 19, 23, and March 7 CMEs. Different from previous event studies, this work attempts to create a general picture for CME Sun-to-Earth propagation and compare different techniques for determining CME interplanetary kinematics. Key results are obtained concerning CME Sun-to-Earth propagation. Our comparison between different techniques (and data sets) also has important implications for CME observations and their interpretations. Future CME observations and space weather forecasting are discussed based on these results. See detail in the PDF.

  14. Técnicas de alongamento coronário

    OpenAIRE

    Basílio, Solange Filipa Andrade

    2016-01-01

    Introdução: O alongamento coronário é um procedimento que pode envolver, ou não, técnicas cirúrgicas, e que tem como principal objetivo aumentar o tamanho da coroa clínica, assim como devolver a estética, a forma e a função às arcadas dentárias. Este procedimento realiza-se, ou por motivos estéticos ou motivos restauradores. Ultimamente, os motivos estéticos têm vindo a ganhar importância e são eles que, muitas da vezes, levam os pacientes às consultas de medicina dentária. O sorriso gengival...

  15. Predicting Coronal Mass Ejections Using Machine Learning Methods

    CERN Document Server

    Bobra, Monica G

    2016-01-01

    Of all the activity observed on the Sun, two of the most energetic events are flares and Coronal Mass Ejections (CMEs). Usually, solar active regions that produce large flares will also produce a CME, but this is not always true (Yashiro et al., 2005). Despite advances in numerical modeling, it is still unclear which circumstances will produce a CME (Webb & Howard, 2012). Therefore, it is worthwhile to empirically determine which features distinguish flares associated with CMEs from flares that are not. At this time, no extensive study has used physically meaningful features of active regions to distinguish between these two populations. As such, we attempt to do so by using features derived from [1] photospheric vector magnetic field data taken by the Solar Dynamics Observatory's Helioseismic and Magnetic Imager instrument and [2] X-ray flux data from the Geostationary Operational Environmental Satellite's X-ray Flux instrument. We build a catalog of active regions that either produced both a flare and a...

  16. Topology of Coronal Fields from Evolving Magnetofrictional Models

    Science.gov (United States)

    DeRosa, Marc L.; Cheung, M.

    2012-05-01

    The evolving magnetofrictional (MF) scheme enables the construction of time-dependent models of the active region coronal magnetic field in response to photospheric driving. When advancing such models, only the magnetic induction is solved, during which the velocity at each point is assumed to be oriented parallel to the Lorentz force. This leads to the field to evolve toward a force-free state. We present results from an evolving MF model of NOAA AR11158 using driving from time sequences of SDO/HMI data. Utilizing this simulation, we investigate changes in magnetic configurations and topology, including the number of null points, evolution of quasi-separatrix layers, and the time-history of total and free magnetic energies as well as relative helicity. This work seeks to elucidate the relation(s) between topological and energetic properties of the AR.

  17. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Directory of Open Access Journals (Sweden)

    Maxim Kramar

    2016-08-01

    Full Text Available Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131 to retrieve and analyze the three-dimensional (3D coronal electron density in the range of heights from $1.5$ to $4 R_odot$ using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 AA band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below $sim 2.5 R_odot$. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  18. Suicide and the Therapeutic Coroner: Inquests, Governance and the Grieving Family

    Directory of Open Access Journals (Sweden)

    Gordon Tait

    2013-11-01

    Full Text Available This study of English Coronial practice raises a number of questions about the role played by the Coroner within contemporary governance. Following observations at over 20 inquests into possible suicides and in-depth interviews with six Coroners, three preliminary issue emerged, all of which pointed to a broader and, in many ways, more significant issue. These preliminary issues are concerned with (1 the existence of considerable slippages between different Coroners over which deaths are likely to be classified as suicide; (2 the high standard of proof required and immense pressure faced by Coroners from family members at inquest to reach any verdict other than suicide, which significantly depresses likely suicide rates; and (3 Coroners feeling no professional obligation, either individually or collectively, to contribute to the production of consistent and useful social data regarding suicide, arguably rendering comparative suicide statistics relatively worthless. These concerns lead, ultimately, to the second more important question about the role expected of Coroners within social governance and within an effective, contemporary democracy. That is, are Coroners the principal officers in the public administration of death; or are they, first and foremost, a crucial part of the grieving process, one that provides important therapeutic interventions into the mental and emotional health of the community?

  19. Decay of Activity Complexes, Formation of Unipolar Magnetic Regions, and Coronal Holes in Their Causal Relation

    Science.gov (United States)

    Golubeva, E. M.; Mordvinov, A. V.

    2016-12-01

    The peculiar development of solar activity in the current cycle resulted in an asynchronous reversal of the Sun's polar fields. The asymmetry is also observed in the formation of polar coronal holes. A stable coronal hole was first formed at the South Pole, despite the later polar-field reversal there. The aim of this study is to understand the processes making this situation possible. Synoptic magnetic maps from the Global Oscillation Network Group and corresponding coronal-hole maps from the Extreme ultraviolet Imaging Telescope onboard the Solar and Heliospheric Observatory and the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory are analyzed here to study the causal relationship between the decay of activity complexes, evolution of large-scale magnetic fields, and formation of coronal holes. Ensembles of coronal holes associated with decaying active regions and activity complexes are presented. These ensembles take part in global rearrangements of the Sun's open magnetic flux. In particular, the south polar coronal hole was formed from an ensemble of coronal holes that came into existence after the decay of multiple activity complexes observed during 2014.

  20. VECTOR TOMOGRAPHY FOR THE CORONAL MAGNETIC FIELD. II. HANLE EFFECT MEASUREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Kramar, M. [Physics Department, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 (United States); Inhester, B. [Max-Planck-Institut fuer Sonnensystemforschung, Max-Plank-Str. 2, D-37191 Katlenburg-Lindau (Germany); Lin, H. [Institute for Astronomy, University of Hawaii at Manoa, 34 Ohia Ku Street, Pukalani, Maui, HI 96768 (United States); Davila, J., E-mail: maxim.i.kramar@nasa.gov, E-mail: Joseph.M.Davila@nasa.gov, E-mail: inhester@mps.mpg.de, E-mail: lin@ifa.hawaii.edu [NASA-GSFC, Code 671, Greenbelt, MD 20771 (United States)

    2013-09-20

    In this paper, we investigate the feasibility of saturated coronal Hanle effect vector tomography or the application of vector tomographic inversion techniques to reconstruct the three-dimensional magnetic field configuration of the solar corona using linear polarization measurements of coronal emission lines. We applied Hanle effect vector tomographic inversion to artificial data produced from analytical coronal magnetic field models with equatorial and meridional currents and global coronal magnetic field models constructed by extrapolation of real photospheric magnetic field measurements. We tested tomographic inversion with only Stokes Q, U, electron density, and temperature inputs to simulate observations over large limb distances where the Stokes I parameters are difficult to obtain with ground-based coronagraphs. We synthesized the coronal linear polarization maps by inputting realistic noise appropriate for ground-based observations over a period of two weeks into the inversion algorithm. We found that our Hanle effect vector tomographic inversion can partially recover the coronal field with a poloidal field configuration, but that it is insensitive to a corona with a toroidal field. This result demonstrates that Hanle effect vector tomography is an effective tool for studying the solar corona and that it is complementary to Zeeman effect vector tomography for the reconstruction of the coronal magnetic field.

  1. Hanle Effect Diagnostics of the Coronal Magnetic Field - A Test Using Realistic Magnetic Field Configurations

    CERN Document Server

    Raouafi, N -E; Wiegelmann, T

    2008-01-01

    Our understanding of coronal phenomena, such as coronal plasma thermodynamics, faces a major handicap caused by missing coronal magnetic field measurements. Several lines in the UV wavelength range present suitable sensitivity to determine the coronal magnetic field via the Hanle effect. The latter is a largely unexplored diagnostic of coronal magnetic fields with a very high potential. Here we study the magnitude of the Hanle-effect signal to be expected outside the solar limb due to the Hanle effect in polarized radiation from the H {\\sc{i}} Ly$\\alpha$ and $\\beta$ lines, which are among the brightest lines in the off-limb coronal FUV spectrum. For this purpose we use a magnetic field structure obtained by extrapolating the magnetic field starting from photospheric magnetograms. The diagnostic potential of these lines for determining the coronal magnetic field, as well as their limitations are studied. We show that these lines, in particular H {\\sc{i}} Ly$\\beta$, are useful for such measurements.

  2. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    Science.gov (United States)

    Kramar, Maxim; Airapetian, Vladimir; Lin, Haosheng

    2016-08-01

    Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from 1.5 to 4 R_⊙ using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 Å band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below ˜ 2.5 R_⊙. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the accuracy of the magnetic field approximations for coronal modeling.

  3. THERMAL STRUCTURE OF CORONAL LOOPS AS SEEN WITH NORIKURA CORONAGRAPH

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, S. Krishna; Singh, Jagdev [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034 (India); Ichimoto, K., E-mail: krishna@iiap.res.in [Kwasan and Hida Observatories, Kyoto University, Yamashina-ku, Kyoto 607-8417 (Japan)

    2013-03-10

    The thermal structure of a coronal loop, both along and across the loop, is vital in determining the exact plasma heating mechanism. High-resolution spectroscopic observations of the off-limb corona were made using the 25 cm Norikura coronagraph, located at Norikura, Japan. Observations on a number of days were made simultaneously in four forbidden iron emission lines, namely, the [Fe XI] 7892 A line, the [Fe XIII] 10747 A and 10798 A lines, and the [Fe XIV] 5303 A line and on some days made only in the [Fe XI] 7892 A and [Fe X] 6374 A lines. Using temperature sensitive emission line ratios [Fe XIV] 5303 A/[Fe XIII] 10747 A and [Fe XI] 7892 A/[Fe X] 6374 A, we compute the electron temperatures along 18 different loop structures observed on different days. We find a significant negative temperature gradient in all of the structures observed in Fe XIV and Fe XIII and a positive temperature gradient in the structures observed in Fe XI and Fe X. Combining these results with the previous investigations by Singh and his collaborators, we infer that the loop tops, in general, appear hotter when observed in colder lines and colder when observed in relatively hotter lines as compared to their coronal foot points. We suggest that this contrasting trend observed in the temperature variation along the loop structures can be explained by a gradual interaction of different temperature plasma. The exact mechanism responsible for this interaction must be investigated further and has the potential to constrain loop heating models.

  4. Bacterial coronal leakage after obturation with three root canal sealers.

    Science.gov (United States)

    Timpawat, S; Amornchat, C; Trisuwan, W R

    2001-01-01

    The purpose of this study was to compare the bacterial leakage of root canals obturated with three root canal sealers, using Endodontalis faecalis as a microbial tracer to determine the length of time for bacteria to penetrate through the obturated root canal to the root apex. Seventy-five, single-rooted teeth with straight root canals had the crown cut off at the cementoenamel junction. Root canals were instrumented by a step-back technique. The prepared teeth were randomly divided into 3 groups of 19 teeth each and another 2 groups as positive and negative controls (9 teeth each). The experimental groups were dependent on the sealer used: AH-Plus, Apexit, and Ketac-Endo. The root canals were obturated using a lateral condensation technique. After 24 h the teeth were attached to microcentrifuge tubes with 2 mm of the root apex submerged in Brain Heart Infusion broth in glass test tubes. The coronal portions of the root canal filling materials were placed in contact with E. faecalis. The teeth were observed for bacterial leakage daily for 30 and 60 days. With the chi2 test for comparing pairs of groups at the 0.05 level (p 0.06), but Apexit had significantly higher leakage (p 0.05), but Apexit leaked more than AH-Plus. The conclusion drawn from this experiment was that epoxy resin root canal sealer was found to be more adaptable to the root canal wall and filling material than a calcium hydroxide sealer when bacterial coronal leakage was studied.

  5. Three-Dimensional Morphology of a Coronal Prominence Cavity

    Science.gov (United States)

    Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hill, S.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Rachmeler, L.; Reeves, K. K.; Schmieder, B.; Schmit, D. J.; Seaton, D. B.; Sterling, A. C.; Tripathi, D.; Williams, D. R.; Zhang, M.

    2010-01-01

    We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft-X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally-extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step towards quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager (EUVI) observations from the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explains the observed variation in cavity visibility for the east vs. west limbs

  6. The Coronal Loop Inventory Project: Expanded Analysis and Results

    Science.gov (United States)

    Schmelz, J. T.; Christian, G. M.; Chastain, R. A.

    2016-11-01

    We have expanded upon earlier work that investigates the relative importance of coronal loops with isothermal versus multithermal cross-field temperature distributions. These results are important for determining if loops have substructure in the form of unresolved magnetic strands. We have increased the number of loops targeted for temperature analysis from 19 to 207 with the addition of 188 new loops from multiple regions. We selected all loop segments visible in the 171 Å images of the Atmospheric Imaging Assembly (AIA) that had a clean background. Eighty-six of the new loops were rejected because they could not be reliably separated from the background in other AIA filters. Sixty-one loops required multithermal models to reproduce the observations. Twenty-eight loops were effectively isothermal, that is, the plasma emission to which AIA is sensitive could not be distinguished from isothermal emission, within uncertainties. Ten loops were isothermal. Also, part of our inventory was one small flaring loop, one very cool loop whose temperature distribution could not be constrained by the AIA data, and one loop with inconclusive results. Our survey can confirm an unexpected result from the pilot study: we found no isothermal loop segments where we could properly use the 171-to-193 ratio method, which would be similar to the analysis done for many loops observed with TRACE and EIT. We recommend caution to observers who assume the loop plasma is isothermal, and hope that these results will influence the direction of coronal heating models and the effort modelers spend on various heating scenarios.

  7. Magnetic reconnection in the interior of interplanetary coronal mass ejections.

    Science.gov (United States)

    Fermo, R L; Opher, M; Drake, J F

    2014-07-18

    Recent in situ observations of interplanetary coronal mass ejections (ICMEs) found signatures of reconnection exhausts in their interior or trailing edge. Whereas reconnection on the leading edge of an ICME would indicate an interaction with the coronal or interplanetary environment, this result suggests that the internal magnetic field reconnects with itself. In light of this data, we consider the stability properties of flux ropes first developed in the context of astrophysics, then further elaborated upon in the context of reversed field pinches (RFPs). It was shown that the lowest energy state of a flux rope corresponds to ∇ × B = λB with λ a constant, the so-called Taylor state. Variations from this state will result in the magnetic field trying to reorient itself into the Taylor state solution, subject to the constraints that the toroidal flux and magnetic helicity are invariant. In reversed field pinches, this relaxation is mediated by the reconnection of the magnetic field, resulting in a sawtooth crash. If we likewise treat the ICME as a flux rope, any deviation from the Taylor state will result in reconnection within the interior of the flux tube, in agreement with the observations by Gosling et al. Such a departure from the Taylor state takes place as the flux tube cross section expands in the latitudinal direction, as seen in magnetohydrodynamic (MHD) simulations of flux tubes propagating through the interplanetary medium. We show analytically that this elongation results in a state which is no longer in the minimum energy Taylor state. We then present magnetohydrodynamic simulations of an elongated flux tube which has evolved away from the Taylor state and show that reconnection at many surfaces produces a complex stochastic magnetic field as the system evolves back to a minimum energy state configuration.

  8. CORONAL MAGNETIC FIELDS DERIVED FROM SIMULTANEOUS MICROWAVE AND EUV OBSERVATIONS AND COMPARISON WITH THE POTENTIAL FIELD MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Miyawaki, Shun; Nozawa, Satoshi [Department of Science, Ibaraki University, Mito, Ibaraki 310-8512 (Japan); Iwai, Kazumasa; Shibasaki, Kiyoto [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Minamimaki, Nagano 384-1305 (Japan); Shiota, Daikou, E-mail: shunmi089@gmail.com [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

    2016-02-10

    We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the differential emission measure measurements using EUV observations. We derived line-of-sight components of the coronal magnetic field from polarization observations of the thermal bremsstrahlung in the NOAA active region 11150, observed around 3:00 UT on 2011 February 3 using the Nobeyama Radioheliograph at 17 GHz. Because the thermal bremsstrahlung intensity at 17 GHz includes both chromospheric and coronal components, we extracted only the coronal component by measuring the coronal emission measure in EUV observations. In addition, we derived only the radio polarization component of the corona by selecting the region of coronal loops and weak magnetic field strength in the chromosphere along the line of sight. The upper limits of the coronal longitudinal magnetic fields were determined as 100–210 G. We also calculated the coronal longitudinal magnetic fields from the potential field extrapolation using the photospheric magnetic field obtained from the Helioseismic and Magnetic Imager. However, the calculated potential fields were certainly smaller than the observed coronal longitudinal magnetic field. This discrepancy between the potential and the observed magnetic field strengths can be explained consistently by two reasons: (1) the underestimation of the coronal emission measure resulting from the limitation of the temperature range of the EUV observations, and (2) the underestimation of the coronal magnetic field resulting from the potential field assumption.

  9. Organización y acción en el sindicalismo de base en argentina: un abordaje conceptual

    Directory of Open Access Journals (Sweden)

    Santiago Duhalde

    2013-12-01

    Full Text Available En este artículo presentamos algunas conclusiones a partir de un estudio realizado en Argentina sobre tres juntas internas de delegados sindicales. El principal objetivo de este trabajo fue analizar la importancia de la dimensión organizacional de las instituciones gremiales en el contexto de su acción sindical. Se trata de un estudio comparativo de tres entidades de base de la Asociación Trabajadores del Estado de Argentina, principalmente durante el período 2003-2010, selección realizada tomando en consideración las principales corrientes políticas presentes en este sindicato. En cuanto a las técnicas de recolección de datos, se conformaron grupos de discusión y se llevaron a cabo entrevistas en profundidad a delegados, afiliados y trabajadores en general. A su vez, se recolectó y analizó una vasta y heterogénea documentación sindical, sumada a información periodística relativa al período estudiado. También la observación participante, llevada a cabo en los distintos lugares de trabajo, resultó de gran ayuda a la hora de la interpretación global de los datos obtenidos. El examen de estas entidades de base se realizó tomando en cuenta un punto de vista procesual, que destaca la presencia de diferentes etapas de estas juntas internas. Esta perspectiva procesual nos permite dar cuenta del grado de relevancia explicativa tanto de los factores organizativos como de los factores de poder disponibles en las distintas etapas de estas juntas, sea a partir de su presencia o ausencia, o a partir del carácter particular que asumen en un período determinado. Como conclusión exponemos la relación que hemos encontrado entre el tipo de organización alcanzado por estas entidades de base y los logros obtenidos por las mismas. En este sentido, una mayor articulación política interna favorece una toma de decisiones unívocas y coherentes en lo que respecta a la relación con terceros actores, lo que repercute favorablemente en la

  10. Coronal holes near the equatorial plane and the solar wind abundance of iron

    Science.gov (United States)

    Ogilvie, K. W.; Coplan, M. A.; Yellin, K. A.

    1996-03-01

    Composition analysis of the solar wind from two equatorial coronal holes has been carried out with the Ion Composition Instrument on the ISEE-3 spacecraft. The abundances of oxygen, neon and iron were determined as coronal hole-related material flowed past the spacecraft. The results show that the edges of the hole-related flow are sharply defined with abundances closer to the abundances in the photosphere than in the slower solar wind. These results are similar to those found in flows from the southern polar coronal hole and suggest an underlying unity between the polar and equatorial regions of the sun.

  11. Ludendorff Coronal Flattening Index of the Total Solar Eclipse on March 9, 2016

    OpenAIRE

    Dani, Tiar; Priyatikanto, Rhorom; Rachman, Abdul

    2016-01-01

    Ludendorff coronal flattening index of the Total Solar Eclipse (TSE) on March 9, 2016, was calculated at various distances in solar radius. As a result, we obtained the coronal flattening index $\\left(\\epsilon =a+b\\right)$ at a distance of 2 solar radii is 0.16. The $24^{th}$ solar cycle phase based on the 2016 TSE event obtained -0.64 which showed the corona is pre-minimum type. Resulted coronal flattening index value gives a predicted maximum amplitude of the monthly sunspot number ($W_{max...

  12. Stellar Coronae with \\textit{XMM-Newton} RGS. I. Coronal Structure

    CERN Document Server

    Güdel, M; Den Boggende, A J F; Brinkman, A C; Den Herder, J W A; Kaastra, J S; Mewe, R; Raassen, A J J; De Vries, C; Behar, E; Cottam, J; Kahn, S M; Paerels, F B S; Peterson, J M; Rasmussen, A P; Sako, M; Branduardi-Raymont, G; Sakelliou, I; Erd, Christian

    2000-01-01

    First results from high-resolution coronal spectroscopy with the {\\it XMM-Newton} Reflection Grating Spectrometers (RGS) are reviewed. Five stellar systems (HR 1099, Capella, Procyon, YY Gem, AB Dor) have been observed. The emphasis of the present paper is on overall coronal structure. Elemental abundances in {\\it active stars} are found to be `anomalous' in the sense that they tend to increase with increasing First Ionization Potential (FIP - i.e., signifying an inverse FIP effect). Coronal densities are measured at levels of a few times $10^{10}$ cm$^{-3}$ for cooler plasma, although there are indications for very high densities in the hotter plasma components.

  13. Self-Consistent MHD Modeling of a Coronal Mass Ejection, Coronal Dimming, and a Giant Cusp-Shaped Arcade Formation

    CERN Document Server

    Shiota, D; Chen, P F; Yamamoto, T T; Sakajiri, T; Shibata, K; Shiota, Daikou; Isobe, Hiroaki; Yamamoto, Tetsuya T.; Sakajiri, Takuma; Shibata, Kazunari

    2005-01-01

    We performed magnetohydrodynamic simulation of coronal mass ejections (CMEs) and associated giant arcade formations, and the results suggested new interpretations of observations of CMEs. We performed two cases of the simulation: with and without heat conduction. Comparing between the results of the two cases, we found that reconnection rate in the conductive case is a little higher than that in the adiabatic case and the temperature of the loop top is consistent with the theoretical value predicted by the Yokoyama-Shibata scaling law. The dynamical properties such as velocity and magnetic fields are similar in the two cases, whereas thermal properties such as temperature and density are very different.In both cases, slow shocks associated with magnetic reconnectionpropagate from the reconnection region along the magnetic field lines around the flux rope, and the shock fronts form spiral patterns. Just outside the slow shocks, the plasma density decreased a great deal. The soft X-ray images synthesized from t...

  14. Reconstruyendo el objeto de la crítica: sobre las posibles confluencias entre psicología crítica y estudios sociales de la ciencia y la tecnología

    Directory of Open Access Journals (Sweden)

    Bruno Jaraba-Barrios

    2010-01-01

    Full Text Available En su calidad de recursos metodológicos y conceptuales que pueden apoyar el propósito de la psicología crítica, se presentan algunos aspectos generales de los estudios sociales de la ciencia y la tecnología (esct, los cuales han abierto promisorias sendas para el abordaje de la recíproca constitución entre ciencia y sociedad. Las directrices del llamado programa fuerte de sociología del conocimiento científico, los métodos y líneas de acción de las etnografías del laboratorio, y el abordaje de análisis retórico a los textos científicos, son los tres principales modelos metodológicos derivados de los esct, expuestos y relacionados con las posibles líneas de investigación dentro de la psicología crítica. Además de tales metodologías, los esct aportan ciertas consideraciones teóricas que son sometidas aquí a discusión con el fin de contribuir a replanteamientos creativos al interior de la psicología crítica.

  15. 77 FR 5057 - Draft Guidelines for Coroner/Medical Examiner Media Relations

    Science.gov (United States)

    2012-02-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Office of Justice Programs Draft Guidelines for Coroner/Medical Examiner Media Relations AGENCY: National... general public a draft document entitled, ``Guidelines for Media Relations: Dissemination of...

  16. Analysis of the solar coronal green line profiles from eclipse observations

    CERN Document Server

    Prabhakar, Maya; Chandrasekhar, T

    2013-01-01

    Analysis of the solar coronal green line profiles reveals information regarding the physical conditions of the solar corona like temperature, density, Doppler velocity, non-thermal velocity etc. It provides insights to the unresolved problems like the coronal heating and the acceleration of the solar winds. Recent studies have reported excess blueshifts in the coronal line profiles and are interpreted as due to nanoflare heating, type II spicules and nascent solar wind flow. We have analyzed a time series of Fabry-Perot interferograms of the solar corona obtained during the total solar eclipse of 2001 June 21 from Lusaka, Zambia. The spatial behavior of the coronal green line profiles were examined and variations in intensity, linewidth, Doppler velocity and line asymmetry were obtained. Several line profiles showed asymmetry indicating the presence of multicomponents. Such line profiles were fitted with double Gaussian curves. It has been found that 42% of the line profiles were single components, 34% were b...

  17. Influence of a coronal envelope as a free boundary to global convective dynamo simulations

    CERN Document Server

    Warnecke, Jörn; Käpylä, Maarit J; Brandenburg, Axel

    2015-01-01

    We explore the effects of an outer stably stratified coronal envelope on rotating turbulent convection, differential rotation, and large-scale dynamo action in spherical wedge models of the Sun. We solve the compressible magnetohydrodynamic equations in a two-layer model with unstable stratification below the surface, representing the convection zone, and a stably stratified outer layer, the coronal envelope. The interface emulates essentially a free surface. We compare with models that have no coronal envelope. The presence of a coronal envelope is found to modify the Reynolds stress and the $\\Lambda$-effect resulting in a weaker and non-cylindrical differential rotation. This is related to the reduced latitudinal temperature variations, which are caused by and dependent on the Coriolis force. Some simulations develop a rudimentary near-surface shear layer, which we can relate to a sign change of the meridional Reynolds stress term in the thermal wind balance equation. Furthermore, the presence of a free sur...

  18. The Sun's Global Photospheric and Coronal Magnetic Fields: Observations and Models

    Directory of Open Access Journals (Sweden)

    Duncan Mackay

    2012-11-01

    Full Text Available In this review, our present day understanding of the Sun’s global photospheric and coronal magnetic fields is discussed from both observational and theoretical viewpoints. Firstly, the large-scale properties of photospheric magnetic fields are described, along with recent advances in photospheric magnetic flux transport models. Following this, the wide variety of theoretical models used to simulate global coronal magnetic fields are described. From this, the combined application of both magnetic flux transport simulations and coronal modeling techniques to describe the phenomena of coronal holes, the Sun’s open magnetic flux and the hemispheric pattern of solar filaments is discussed. Finally, recent advances in non-eruptive global MHD models are described. While the review focuses mainly on solar magnetic fields, recent advances in measuring and modeling stellar magnetic fields are described where appropriate. In the final section key areas of future research are identified.

  19. A Data-Driven Analytic Model for Proton Acceleration by Large-Scale Solar Coronal Shocks

    CERN Document Server

    Kozarev, Kamen A

    2016-01-01

    We have recently studied the development of an eruptive filament-driven, large-scale off-limb coronal bright front (OCBF) in the low solar corona (Kozarev et al. 2015), using remote observations from Solar Dynamics Observatory's Advanced Imaging Assembly EUV telescopes. In that study, we obtained high-temporal resolution estimates of the OCBF parameters regulating the efficiency of charged particle acceleration within the theoretical framework of diffusive shock acceleration (DSA). These parameters include the time-dependent front size, speed, and strength, as well as the upstream coronal magnetic field orientations with respect to the front's surface normal direction. Here we present an analytical particle acceleration model, specifically developed to incorporate the coronal shock/compressive front properties described above, derived from remote observations. We verify the model's performance through a grid of idealized case runs using input parameters typical for large-scale coronal shocks, and demonstrate ...

  20. Thermal and non-thermal emission from reconnecting twisted coronal loops

    CERN Document Server

    Pinto, R; Browning, P K; Vilmer, N

    2016-01-01

    Twisted magnetic fields should be ubiquitous in the solar corona. The magnetic energy contained in such twisted fields can be released during solar flares and other explosive phenomena. Reconnection in helical magnetic coronal loops results in plasma heating and particle acceleration distributed within a large volume, including the lower coronal and chromospheric sections of the loops, and can be a viable alternative to the standard flare model, where particles are accelerated only in a small volume located in the upper corona. The goal of this study is to investigate the observational signatures of plasma heating and particle acceleration in kink-unstable twisted coronal loops using combination of MHD simulations and test-particle methods. The simulations describe the development of kink instability and magnetic reconnection in twisted coronal loops using resistive compressible MHD, and incorporate atmospheric stratification and large-scale loop curvature. The resulting distributions of hot plasma let us est...

  1. Coronal Pseudo-Streamer and Bipolar Streamer Observed by SOHO/UVCS in March 2008

    CERN Document Server

    Abbo, Lucia; Riley, Pete; Wang, Yi-Ming

    2015-01-01

    The last solar minimum is characterized by several peculiar aspects and by the presence of a complex magnetic topology with two different kinds of coronal streamers: pseudo-streamers and bipolar streamers. Pseudo-streamers or unipolar streamer are coronal structures which separate coronal holes of the same polarity, without a current sheet in the outer corona; unlike bipolar streamer that separate coronal holes of opposite magnetic polarity. In this study, two examples of these structures have been identified in the period of Carrington rotation 2067, by applying a potential-field source-surface extrapolation of the photospheric field measurements. We present a spectroscopic analysis of a pseudo-streamer and a bipolar streamer observed in the period 12-17 March 2008 at high spectral and spatial resolution by the Ultraviolet Coronagraph Spectrometer (UVCS; Kohl et al., 1995) onboard Solar and Heliospheric Observatory (SOHO). The solar wind plasma parameters, such as kinetic temperature, electron density and ou...

  2. MAGNETOHYDRODYNAMIC WAVES AND CORONAL HEATING: UNIFYING EMPIRICAL AND MHD TURBULENCE MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Igor V.; Van der Holst, Bart; Oran, Rona; Jin, Meng; Manchester, Ward B. IV; Gombosi, Tamas I. [Department of AOSS, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109 (United States); Downs, Cooper [Predictive Science Inc., 9990 Mesa Rim Road, Suite 170, San Diego, CA 92121 (United States); Roussev, Ilia I. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Evans, Rebekah M., E-mail: igorsok@umich.edu [NASA Goddard Space Flight Center, Space Weather Lab, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States)

    2013-02-10

    We present a new global model of the solar corona, including the low corona, the transition region, and the top of the chromosphere. The realistic three-dimensional magnetic field is simulated using the data from the photospheric magnetic field measurements. The distinctive feature of the new model is incorporating MHD Alfven wave turbulence. We assume this turbulence and its nonlinear dissipation to be the only momentum and energy source for heating the coronal plasma and driving the solar wind. The difference between the turbulence dissipation efficiency in coronal holes and that in closed field regions is because the nonlinear cascade rate degrades in strongly anisotropic (imbalanced) turbulence in coronal holes (no inward propagating wave), thus resulting in colder coronal holes, from which the fast solar wind originates. The detailed presentation of the theoretical model is illustrated with the synthetic images for multi-wavelength EUV emission compared with the observations from SDO AIA and STEREO EUVI instruments for the Carrington rotation 2107.

  3. Constraints On Solar Wind Plasma Properties Derived From Coordinated Coronal Observations

    Science.gov (United States)

    Esser, Ruth; Wagner, William (Technical Monitor)

    2002-01-01

    The goal of the proposed research is to increase the understanding of coroner plasma phenomena by making use of different observational approaches and combine the observations with the necessary theoretical considerations.

  4. An atlas of coronal electron density at 5Rs I: Data processing and calibration

    CERN Document Server

    Morgan, Huw

    2015-01-01

    Tomography of the solar corona can provide cruicial constraints for models of the low corona, unique information on changes in coronal structure and rotation rates, and a valuable boundary condition for models of the heliospheric solar wind. This is the first of a series of three papers which aim to create a set of maps of the coronal density over an extended period (1996-present). The papers will describe the data processing and calibration (this paper), the tomography method (\\paperii) and resulting atlas of coronal electron density at a height of 5\\Rs\\ between years 1996-2014 (\\paperiii). This first paper presents a detailed description of data processing and calibration for the Large-Angle and Spectrometric Coronagraph (LASCO) C2 instrument onboard the Solar and Heliospheric Observatory (SOHO) and the COR2 instruments of the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) package aboard the Solar Terrestial Relations Observatory (STEREO) A \\& B spacecraft. The methodology includes...

  5. Improvements on coronal hole detection in SDO/AIA images using supervised classification

    CERN Document Server

    Reiss, Martin A; De Visscher, Ruben; Temmer, Manuela; Veronig, Astrid M; Delouille, Véronique; Mampaey, Benjamin; Ahammer, Helmut

    2015-01-01

    We demonstrate the use of machine learning algorithms in combination with segmentation techniques in order to distinguish coronal holes and filaments in SDO/AIA EUV images of the Sun. Based on two coronal hole detection techniques (intensity-based thresholding, SPoCA), we prepared data sets of manually labeled coronal hole and filament channel regions present on the Sun during the time range 2011 - 2013. By mapping the extracted regions from EUV observations onto HMI line-of-sight magnetograms we also include their magnetic characteristics. We computed shape measures from the segmented binary maps as well as first order and second order texture statistics from the segmented regions in the EUV images and magnetograms. These attributes were used for data mining investigations to identify the most performant rule to differentiate between coronal holes and filament channels. We applied several classifiers, namely Support Vector Machine, Linear Support Vector Machine, Decision Tree, and Random Forest and found tha...

  6. First use of synoptic vector magnetograms for global nonlinear force free coronal magnetic field models

    CERN Document Server

    Tadesse, Tilaye; Gosain, S; MacNeice, P; Pevtsov, Alexei A

    2013-01-01

    The magnetic field permeating the solar atmosphere is generally thought to provide the energy for much of the activity seen in the solar corona, such as flares, coronal mass ejections (CMEs), etc. To overcome the unavailability of coronal magnetic field measurements, photospheric magnetic field vector data can be used to reconstruct the coronal field. Currently there are several modelling techniques being used to calculate three-dimension of the field lines into the solar atmosphere. For the first time, synoptic maps of photospheric vector magnetic field synthesized from Vector Spectromagnetograph (VSM) on Synoptic Optical Long-term Investigations of the Sun (SOLIS) are used to model the coronal magnetic field and estimate free magnetic energy in the global scale. The free energy (i.e., the energy in excess of the potential field energy) is one of the main indicators used in space weather forecasts to predict the eruptivity of active regions. We solve the nonlinear force-free field equations using optimizatio...

  7. Comparing High-speed Transition Region Jets in Coronal Holes and Quiet Sun Regions

    Science.gov (United States)

    Tate Arbacher, Rebecca; Tian, Hui; Cranmer, Steven R.

    2015-01-01

    The complicated energy transfer and plasma motion in the transition region, between the photosphere and the corona, may play a significant role in the formation and acceleration of the solar wind. New observations from the Interface Region Imaging Spectrograph (IRIS) have revealed unprecedented levels of detail in this less-studied region. Coronal holes in particular are a likely source of solar wind material, though the formation and acceleration mechanisms of the fast solar wind are still largely unknown. In our previous work, we have reported the prevalence of small-scale high-speed (~80-250 km/s) jets with transition region temperatures from the network structures of coronal holes. Here we undertake a comparative study of these short-lived episodic network jets in a coronal hole region and a quiet sun region using IRIS sit-and-stare slit-jaw imaging in the 1330 Angstrom (C II) passband. The pointing coordinates, exposure time, observing cadence, and field of view of both observations are all identical. Our preliminary study suggests that the speeds and lengths of the network jets may differ between quiet sun and coronal hole regions. The quiet sun region exhibits many compact bright regions with sizes of 5-10 arcseconds which produce very few jets. The jets that do exist tend to propagate at much slower speeds over smaller distances than their coronal hole counterparts. Comparatively, in the coronal hole, such compact regions are almost absent and all network patches are permeated by the intermittent high-reaching jets. Such a difference suggests that magnetic loops are much smaller in the coronal hole and the network jets are produced at low heights. The recurrence frequency seems to be higher in the coronal hole region, with many of the isolated quiet sun region jets demonstrating curved trajectories.This work is supported under contract 8100002705 from Lockheed-Martin to SAO and by the NSF-REU solar physics program at SAO, grant number AGS-1263241.

  8. Spectroscopic Studies of Solar Corona VI: Trend in Line-width Variation of Coronal Emission Lines with Height Independent of the Structure of Coronal Loops

    Indian Academy of Sciences (India)

    Jagdev Singh; Takashi Sakurai; Kiyoshi Ichimoto; S. Muneer

    2006-06-01

    We have obtained spectroscopic observations in coronal emission lines by choosing two lines simultaneously, one [Fe X] 6374 Å and the other [Fe XI] 7892 Å or [Fe XIII] 10747 Å or [Fe XIV] 5303 Å. We found that in 95 per cent of the coronal loops observed in 6374 Å, the FWHM of the emission line increases with height above the limb irrespective of the size, shape and orientation of the loop and that in case of 5303 Å line decreases with height in about 89 per cent of the coronal loops. The FWHM of 7892 Å and 10747 Å emission lines show intermediate behavior. The increase in the FWHM of 6374 Å line with height is the steepest among these four lines.We have also studied the intensity ratio and ratio of FWHM of these lines with respect to those of 6374 Å as a function height above the limb. We found that the intensity ratio of 7892 Å and 10747 Å lines with respect to 6374 Å line increases with height and that of 5303 Å to 6374 Å decreases with height above the limb. This implies that temperature in coronal loops will appear to increase with height in the intensity ratio plots of 7892 Å and 6374 Å; and 10747 Å and 6374 Å whereas it will appear to decrease with height in intensity ratio of 5303 Å to 6374 Å line versus height plot. These findings are up to a height of about 200 arcsec above the limb. The varying ratios with height indicate that relatively hotter and colder plasma in coronal loops interact with each other. Therefore, the observed increase in FWHM with height above the limb of coronal emission lines associated with plasma at about 1 MK may not be due to increase in non-thermal motions caused by coronal waves but due to interaction with the relatively hotter plasma. These findings also do not support the existing coronal loop models, which predict an increase in temperature of the loop with height above the limb.

  9. Trans trochanteric approach with coronal osteotomy of the great trochanter

    Directory of Open Access Journals (Sweden)

    Steffann Francois

    2015-01-01

    Full Text Available Several surgical approaches could be used in hip arthroplasty or trauma surgery: anterior, anterolateral, lateral, posterior (with or without trochanterotomy, using or not an orthopedic reduction table. Subtrochanteric and extra-capsular trochanteric fractures (ECTF are usually treated by internal fixation with mandatory restrictions on weight bearing. Specific complications have been widely described. Mechanical failures are particularly high in unstable fractures. Hip fractures are a major public health issue with a mortality rate of 12%–23% at 1 year. An alternative option is to treat ECTF by total hip arthroplasty (THA to prevent decubitus complications, to help rapid recovery, and to permit immediate weight bearing as well as quick rehabilitation. However, specific risks of THA have to be considered such as dislocation or cardiovascular failure. The classical approach (anterior or posterior requires the opening of the joint and capsule, weakening hip stability and the repair of the great trochanter is sometimes hazardous. For 15 years, we have been treating unstable ECTF by THA with cementless stem, dual mobility cup (DMC, greater trochanter (GT reattachment, and a new surgical approach preserving capsule, going through the fracture and avoiding joint dislocation. Bombaci first described a similar approach in 2008; our trans fractural digastric approach (medial gluteus and lateral vastus is different. A coronal GT osteotomy is performed when there is no coronal fracture line. It allows easy access to the femoral neck and acetabulum. The THA is implanted without femoral internal rotation to avoid extra bone fragment displacement. With pre-operative planning, cup implantation is easy and stem positioning is adjusted referring to the top of the GT after trial reduction and preoperative planning. The longitudinal osteotomy and trochanteric fracture are repaired with wires and the digastric incision is closed. This variant of Bombaci

  10. Formation and evolution of coronal rain observed by SDO/AIA on February 22, 2012

    CERN Document Server

    Vashalomidze, Z; Zaqarashvili, T V; Oliver, R; Shergelashvili, B; Ramishvili, G; Poedts, S; De Causmaecker, P

    2015-01-01

    The formation and dynamics of coronal rain are currently not fully understood. Coronal rain is the fall of cool and dense blobs formed by thermal instability in the solar corona towards the solar surface with acceleration smaller than gravitational free fall. We aim to study the observational evidence of the formation of coronal rain and to trace the detailed dynamics of individual blobs. We used time series of the 171 \\AA\\, and 304 \\AA\\, spectral lines obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) above active region AR 11420 on February 22, 2012. Observations show that a coronal loop disappeared in the 171 \\AA\\ channel and appeared in the 304 \\AA\\ line$\\text{}\\text{}$ more than one hour later, which indicates a rapid cooling of the coronal loop from 1 MK to 0.05 MK. An energy estimation shows that the radiation is higher than the heat input, which indicates so-called catastrophic cooling. The cooling was accompanied by the formation of coronal rain in the fo...

  11. Coronal energy input and dissipation in a solar active region 3D MHD model

    CERN Document Server

    Bourdin, Philippe-A; Peter, Hardi

    2015-01-01

    Context. We have conducted a 3D MHD simulation of the solar corona above an active region in full scale and high resolution, which shows coronal loops, and plasma flows within them, similar to observations. Aims. We want to find the connection between the photospheric energy input by field-line braiding with the coronal energy conversion by Ohmic dissipation of induced currents. Methods. To this end we compare the coronal energy input and dissipation within our simulation domain above different fields of view, e.g. for a small loops system in the active region (AR) core. We also choose an ensemble of field lines to compare, e.g., the magnetic energy input to the heating per particle along these field lines. Results. We find an enhanced Ohmic dissipation of currents in the corona above areas that also have enhanced upwards-directed Poynting flux. These regions coincide with the regions where hot coronal loops within the AR core are observed. The coronal density plays a role in estimating the coronal temperatur...

  12. Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV and IR Lines

    CERN Document Server

    Raouafi, N E; Gibson, S; Fineschi, S; Solanki, S K

    2016-01-01

    The plasma thermodynamics in the solar upper atmosphere, particularly in the corona, are dominated by the magnetic field, which controls the flow and dissipation of energy. The relative lack of knowledge of the coronal vector magnetic field is a major handicap for progress in coronal physics. This makes the development of measurement methods of coronal magnetic fields a high priority in solar physics. The Hanle effect in the UV and IR spectral lines is a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations to study the magnitude of the signal to be expected for typical coronal magnetic fields for selected spectral lines in the UV and IR wavelength ranges, namely the H I Ly-$\\alpha$ and the He I 10830 {\\AA} lines. We show that the selected lines are useful for reliable diagnosis of coronal magnetic fields. The results show that the combination of polarization measurements of spectral lines with different sensitivities to the Hanle effect may be most appropriate for deducing coronal magne...

  13. EFFECT OF CORONAL TEMPERATURE ON THE SCALE OF SOLAR CHROMOSPHERIC JETS

    Energy Technology Data Exchange (ETDEWEB)

    Iijima; Yokoyama, T.H., E-mail: h.iijima@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2015-10-20

    We investigate the effect of coronal temperature on the formation process of solar chromospheric jets using two-dimensional magnetohydrodynamic simulations of the region from the upper convection zone to the lower corona. We develop a new radiative magnetohydrodynamic code for the dynamic modeling of the solar atmosphere, employing an LTE equation of state, optically thick radiative loss in the photosphere, optically thin radiative loss in the chromosphere and the corona, and thermal conduction along the magnetic field lines. Many chromospheric jets are produced in the simulations by shock waves passing through the transition region. We find that these jets are projected farther outward when the coronal temperature is lower (similar to that in coronal holes) and shorter when the coronal temperature is higher (similar to that in active regions). When the coronal temperature is high, the deceleration of the chromospheric jets is consistent with the model in which deceleration is determined by the periodic chromospheric shock waves. However, when the coronal temperature is low, the gravitational deceleration becomes more important and the chromospheric jets approach ballistic motion.

  14. Solar Coronal Loops Associated with Small-scale Mixed Polarity Surface Magnetic Fields

    Science.gov (United States)

    Chitta, L. P.; Peter, H.; Solanki, S. K.; Barthol, P.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Riethmüller, T. L.; van Noort, M.; Blanco Rodríguez, J.; Del Toro Iniesta, J. C.; Orozco Suárez, D.; Schmidt, W.; Martínez Pillet, V.; Knölker, M.

    2017-03-01

    How and where are coronal loops rooted in the solar lower atmosphere? The details of the magnetic environment and its evolution at the footpoints of coronal loops are crucial to understanding the processes of mass and energy supply to the solar corona. To address the above question, we use high-resolution line-of-sight magnetic field data from the Imaging Magnetograph eXperiment instrument on the Sunrise balloon-borne observatory and coronal observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory of an emerging active region. We find that the coronal loops are often rooted at the locations with minor small-scale but persistent opposite-polarity magnetic elements very close to the larger dominant polarity. These opposite-polarity small-scale elements continually interact with the dominant polarity underlying the coronal loop through flux cancellation. At these locations we detect small inverse Y-shaped jets in chromospheric Ca ii H images obtained from the Sunrise Filter Imager during the flux cancellation. Our results indicate that magnetic flux cancellation and reconnection at the base of coronal loops due to mixed polarity fields might be a crucial feature for the supply of mass and energy into the corona.

  15. Structure of solar coronal loops: from miniature to large-scale

    CERN Document Server

    Peter, H; Klimchuk, J A; de Forest, C; Cirtain, J W; Golub, L; Winebarger, A R; Kobayashi, K; Korreck, K E

    2013-01-01

    We will use new data from the High-resolution Coronal Imager (Hi-C) with unprecedented spatial resolution of the solar corona to investigate the structure of coronal loops down to 0.2 arcsec. During a rocket flight Hi-C provided images of the solar corona in a wavelength band around 193 A that is dominated by emission from Fe XII showing plasma at temperatures around 1.5 MK. We analyze part of the Hi-C field-of-view to study the smallest coronal loops observed so far and search for the a possible sub-structuring of larger loops. We find tiny 1.5 MK loop-like structures that we interpret as miniature coronal loops. These have length of the coronal segment above the chromosphere of only about 1 Mm and a thickness of less than 200 km. They could be interpreted as the coronal signature of small flux tubes breaking through the photosphere with a footpoint distance corresponding to the diameter of a cell of granulation. We find loops that are longer than 50 Mm to have a diameter of about 2 arcsec or 1.5 Mm, consist...

  16. 3D Global Coronal Density Structure and Associated Magnetic Field near Solar Maximum

    CERN Document Server

    Kramar, Maxim; Lin, Haosheng

    2016-01-01

    Measurement of the coronal magnetic field is a crucial ingredient in understanding the nature of solar coronal dynamic phenomena at all scales. We employ STEREO/COR1 data obtained near maximum of solar activity in December 2012 (Carrington rotation, CR 2131) to retrieve and analyze the three-dimensional (3D) coronal electron density in the range of heights from $1.5$ to $4\\ \\mathrm{R}_\\odot$ using a tomography method and qualitatively deduce structures of the coronal magnetic field. The 3D electron density analysis is complemented by the 3D STEREO/EUVI emissivity in 195 \\AA \\ band obtained by tomography for the same CR period. We find that the magnetic field configuration during CR 2131 has a tendency to become radially open at heliocentric distances below $\\sim 2.5 \\ \\mathrm{R}_\\odot$. We compared the reconstructed 3D coronal structures over the CR near the solar maximum to the one at deep solar minimum. Results of our 3D density reconstruction will help to constrain solar coronal field models and test the a...

  17. Additional merit of coronal STIR imaging for MR imaging of lumbar spine

    Directory of Open Access Journals (Sweden)

    Ranjana Gupta

    2015-01-01

    Full Text Available Introduction: Back pain is a common clinical problem and is the frequent complaint for referral of lumbar spine magnetic resonance imaging (MRI. Coronal short tau inversion recovery sequence (STIR can provide diagnostically significant information in small percentage of patients. Materials and Methods: MRI examinations of a total of 350 patients were retrospectively included in the study. MR sequences were evaluated in two settings. One radiologist evaluated sagittal and axial images only, while another radiologist evaluated all sequences, including coronal STIR sequence. After recording the diagnoses, we compared the MRI findings in two subsets of patients to evaluate additional merit of coronal STIR imaging. Results: With addition of coronal STIR imaging, significant findings were observed in 24 subjects (6.8%. Twenty-one of these subjects were considered to be normal on other sequences and in three subjects diagnosis was changed with the addition of coronal STIR. Additional diagnoses on STIR included sacroiliitis, sacroiliac joint degenerative disease, sacral stress/insufficiency fracture/Looser′s zones, muscular sprain and atypical appendicitis. Conclusion: Coronal STIR imaging can provide additional diagnoses in a small percentage of patients presenting for lumbar spine MRI for back pain. Therefore, it should be included in the routine protocol for MR imaging of lumbar spine.

  18. Large Geomagnetic Storms Associated with Limb Halo Coronal Mass Ejections

    CERN Document Server

    Gopalswamy, Nat; Xie, Hong; Akiyama, Sachiko; Makela, Pertti

    2009-01-01

    Solar cycle 23 witnessed the observation of hundreds of halo coronal mass ejections (CMEs), thanks to the high dynamic range and extended field of view of the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO) mission. More than two thirds of halo CMEs originating on the front side of the Sun have been found to be geoeffective (Dst = 45deg) have a 20% shorter delay time on the average. It was suggested that the geomagnetic storms due to limb halos must be due to the sheath portion of the interplanetary CMEs (ICMEs) so that the shorter delay time can be accounted for. We confirm this suggestion by examining the sheath and ejecta portions of ICMEs from Wind and ACE data that correspond to the limb halos. Detailed examination showed that three pairs of limb halos were interacting events. Geomagnetic storms following five limb halos were actually produced by other disk halos. The storms followed by four isolated limb halos and the ones associated with interact...

  19. Understanding the Physical Nature of Coronal "EIT Waves"

    Science.gov (United States)

    Long, D. M.; Bloomfield, D. S.; Chen, P. F.; Downs, C.; Gallagher, P. T.; Kwon, R.-Y.; Vanninathan, K.; Veronig, A. M.; Vourlidas, A.; Vršnak, B.; Warmuth, A.; Žic, T.

    2017-01-01

    For almost 20 years the physical nature of globally propagating waves in the solar corona (commonly called "EIT waves") has been controversial and subject to debate. Additional theories have been proposed over the years to explain observations that did not agree with the originally proposed fast-mode wave interpretation. However, the incompatibility of observations made using the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory with the fast-mode wave interpretation was challenged by differing viewpoints from the twin Solar Terrestrial Relations Observatory spacecraft and data with higher spatial and temporal resolution from the Solar Dynamics Observatory. In this article, we reexamine the theories proposed to explain EIT waves to identify measurable properties and behaviours that can be compared to current and future observations. Most of us conclude that the so-called EIT waves are best described as fast-mode large-amplitude waves or shocks that are initially driven by the impulsive expansion of an erupting coronal mass ejection in the low corona.

  20. A scenario of planet erosion by coronal radiation

    CERN Document Server

    Sanz-Forcada, J; Micela, G; Pollock, A M T; Garcia-Alvarez, D; Solano, E; Eiroa, C

    2010-01-01

    Context: According to theory, high-energy emission from the coronae of cool stars can severely erode the atmospheres of orbiting planets. No observational tests of the long term effects of erosion have yet been made. Aims: To analyze the current distribution of planetary mass with X-ray irradiation of the atmospheres in order to make an observational assessment of the effects of erosion by coronal radiation. Methods: We study a large sample of planet-hosting stars with XMM-Newton, Chandra and ROSAT; make a careful identification of X-ray counterparts; and fit their spectra to make accurately measurements of the stellar X-ray flux. Results: The distribution of the planetary masses with X-ray flux suggests that erosion has taken place: most surviving massive planets, (M_p sin i >1.5 M_J), have been exposed to lower accumulated irradiation. Heavy erosion during the initial stages of stellar evolution is followed by a phase of much weaker erosion. A line dividing these two phases could be present, showing a stron...