32 resultados para prominences


Relevância:

20.00% 20.00%

Publicador:

Resumo:

We present Roche tomograms of the G5-G8 IV/V secondary star in the long-period cataclysmic variable BV Cen reconstructed from Magellan Inamori Kyocera Echelle spectrograph echelle data taken on the Magellan Clay 6.5-m telescope. The tomograms show the presence of a number of large, cool star-spots on BV Cen for the first time. In particular, we find a large high-latitude spot which is deflected from the rotational axis in the same direction as seen on the K3-K5 IV/V secondary star in the cataclysmic variable AE Aqr. BV Cen also shows a similar relative paucity of spots at latitudes between 40° and 50° when compared with AE Aqr. Furthermore, we find evidence for an increased spot coverage around longitudes facing the white dwarf which supports models invoking star-spots at the L1 point to explain the low states observed in some cataclysmic variables. In total, we estimate that some 25 per cent of the Northern hemisphere of BV Cen is spotted. We also find evidence for a faint, narrow, transient emission line with characteristics reminiscent of the peculiar low-velocity emission features observed in some outbursting dwarf novae. We interpret this feature as a slingshot prominence from the secondary star and derive a maximum source size of 75000 km and a minimum altitude of 160000 km above the orbital plane for the prominence. The entropy landscape technique was applied to determine the system parameters of BV Cen. We find M1 = 1.18 +/-0.280.16Msolar and M2 = 1.05 +/-0.230.14Msolar and an orbital inclination of i = 53° +/- 4° at an optimal systemic velocity of ? = -22.3 km s-1. Finally, we also report on the previously unknown binarity of the G5IV star HD 220492.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

There are several examples of horizontal ringlike prominences in the observations of Ha monochromatic image of the sun. In the present paper the statie equilibrium of the plasma loop is discussed. The analytic solutions to magnetic field and density are obtained for the axisymmetrie case under the closed boundary condition. Results show the great influence of the gravity and different force-free factors on the configurations of magnetic surfaces and the distributions of thermodynamical quantities for the prominence.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In 1980 the Beijing Observatory had successively observed sevesal rare completely closed ring prominences whose ring plane was approximately parallel to the solar surface with a characteristic life about 1—2 days. In this paper we discuss the static equilibrium of this kind of horizontal ring plasma under the simultaneous actions of magnetic force, gravity and pressure gradients. Assuming ring plasma with axisymmetry and rectangular plasma cross-section and adopting closed magnetic field boundary condition from the basic equations we obtain the exact zero order general solutions for magnetic field (force-free field) and density (pressure). We further obtain an eigen-solution for the zero order magnetic field and density as well as the first order magnetic field, thus giving a kind of the possible distribution of magnetic field and density for the horizontal closed ring prominence. The closed magnetic structure of ring prominence as presented in this paper, has no link with the force lines of the outside corona magnetic field. This is helpful to explain the great temperature difference between prominenee and corona.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A contaminação do ar e do meio ambiente por combustíveis derivados de petróleo tem sido objeto de crescente pesquisa no Brasil. Dentre os tipos de poluição ao meio ambiente, a poluição atmosférica é a que causa mais incômodo à população. Esta exerce efeitos sobre a saúde humana, causando desde simples irritações até câncer de pulmão. Dos poluentes mais perigosos encontrados nesses ambientes, são destaques os hidrocarbonetos e os compostos monoaromáticos como o benzeno, tolueno e xilenos (BTX), presentes nesses combustíveis, que são extremamente tóxicos à saúde humana. Para controle desses compostos orgânicos voláteis, é necessário quantificá-los e compará-los aos valores limites de tolerância legislados no Brasil. A utilização da técnica de cromatografia gasosa e da técnica de espectroscopia por infravermelho permite realizar essa tarefa de maneira relativamente simples e rápida. Portanto o objetivo deste trabalho foi apresentar a composição química de amostras de gasolina do tipo C comercializadas nos postos revendedores da Região Metropolitana do Estado do Rio de Janeiro. Foram feitas análises quantitativas dos principais grupos químicos (parafínicos, olefínicos, naftênicos e aromáticos) e etanol por Cromatografia Gasosa de Alta Resolução e da composição de benzeno, tolueno e xileno (BTX) pela técnica de absorção no infravermelho. Os resultados foram comparados com os limites dados pela especificação da ANP (Portaria n 309) para a qualidade da gasolina, com o objetivo de se verificar se estão em conformidade com este agente regulamentador. Os resultados mostraram que todos os teores encontrados de olefínicos e aromáticos foram abaixo do limite especificado. Alguns postos apresentaram os teores de benzeno acima do limite especificado, indicando um nível de ação por parte da ANP principalmente pela ação tóxica do benzeno

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This research, mainly by using perceptual experiment and relating its results to the acoustic correlates, investigated the acoustic correlates of mandarin prominences of prosodic word、prosodic phrase、sentence and their mutual influences. The results are as follow: (1) for the prominence of prosodic word, according the order of the extents to which these acoustic correlates contribute to the perception of the prominence, its acoustic correlates are duration、pitch、spectral tilt、energy and pitch-change, the results also have showed that the perception of the prominence is influenced by some non-acoustic factors; (2) for the prominence of prosodic phrase, baseing on the experimental results, the existing of prosodic phrase prominence in mandarian has been proposed, and the experiments proved that the prosodic phrase prominence fall on the semantic focus of the phrase typically; (3) for the prominence of sentence, the experimental results show that, the lengthening of duration, similar with the pitch-change, mainly localised on the prosodic head of the domain on which the sentence prominence emphisize, and this lengthening would, in different levels, spread on other syllables in the phonetic constituents which contain the prosodic head, and this pattern of lengthening of duration does not vary with changing of domain of sentence prominence, that means, in mandarin sentence, there is generally no acoustic cues which can been used in the perception of the domain of sentnece prominence; (4) for the acoustic cues of mutual influences of the prominences of different levels, the experiment have proved that, not only the pitch-change but also the lengthening of duration are subjective to melodic grid law. In the last part of the dissertation, I have tried to given an explantion about the above experimental results from psylogical view point.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Habbal, Shadia Rifai; Morgan, Huw; Johnson, Judd; Arndt, Martina Belz; Daw, Adrian; Jaeggli, Sarah; Kuhn, Jeff; Mickey, Don, LOCALIZED ENHANCEMENTS OF Fe+10 DENSITY IN THE CORONA AS OBSERVED IN Fe xi 789.2 nm DURING THE 2006 MARCH 29 TOTAL SOLAR ECLIPSE, The Astrophysical Journal, Volume 663, Issue 1, pp. 598-609

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Morgan, H.; Habbal, S. R., An empirical 3D model of the large-scale coronal structure based on the distribution of H? filaments on the solar disk, Astronomy and Astrophysics, Volume 464, Issue 1, March II 2007, pp.357-365

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aims. We study the formation and evolution of a failed filament eruption observed in NOAA active region 11121 near the southeast
limb on November 6, 2010.
Methods. We used a time series of SDO/AIA 304, 171, 131, 193, 335, and 94 Å images, SDO/HMI magnetograms, as well as ROSA
and ISOON Hα images to study the erupting active region.
Results. We identify coronal loop arcades associated with a quadrupolar magnetic configuration, and show that the expansion and
cancellation of the central loop arcade system over the filament is followed by the eruption of the filament. The erupting filament
reveals a clear helical twist and develops the same sign of writhe in the form of inverse γ-shape.
Conclusions. The observations support the “magnetic breakout” process in which the eruption is triggered by quadrupolar reconnection
in the corona. We propose that the formation mechanism of the inverse γ-shape flux rope is the magnetohydrodynamic helical
kink instability. The eruption has failed because of the large-scale, closed, overlying magnetic loop arcade that encloses the active
region

Relevância:

10.00% 10.00%

Publicador:

Resumo:

By means of numerical simulations, we investigate magnetized stellar winds of pre-main-sequence stars. In particular, we analyze under which circumstances these stars will present elongated magnetic features (e.g., helmet streamers, slingshot prominences, etc). We focus on weak-lined T Tauri stars, as the presence of the tenuous accretion disk is not expected to have strong influence on the structure of the stellar wind. We show that the plasma-beta parameter (the ratio of thermal to magnetic energy densities) is a decisive factor in defining the magnetic configuration of the stellar wind. Using initial parameters within the observed range for these stars, we show that the coronal magnetic field configuration can vary between a dipole-like configuration and a configuration with strong collimated polar lines and closed streamers at the equator (multicomponent configuration for the magnetic field). We show that elongated magnetic features will only be present if the plasma-beta parameter at the coronal base is beta(0) << 1. Using our self-consistent three-dimensional magnetohydrodynamics model, we estimate for these stellar winds the timescale of planet migration due to drag forces exerted by the stellar wind on a hot-Jupiter. In contrast to the findings of Lovelace et al., who estimated such timescales using the Weber and Davis model, our model suggests that the stellar wind of these multicomponent coronae are not expected to have significant influence on hot-Jupiters migration. Further simulations are necessary to investigate this result under more intense surface magnetic field strengths (similar to 2-3 kG) and higher coronal base densities, as well as in a tilted stellar magnetosphere.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Analisar a atuação dos enfermeiros de unidade de terapia intensiva na prevenção da úlcera por pressão. Método: trata-se de estudo descritivo desenvolvido com 13 enfermeiros da unidade de terapia intensiva do Hospital Universitário Onofre Lopes (HUOL), em Natal-RN. Foi aplicado um questionário, submetido à análise de conteúdo temática. O estudo foi aprovado pelo Comitê de Ética da Universidade Federal do Rio Grande do Norte (UFRN), sob o CAAE n. 0240.0.051.000-10. Resultados: os enfermeiros reportaram a realização da mudança de decúbito, a avaliação de risco, a discussão com os colegas sobre as medidas adotadas, a higiene e hidratação da pele do paciente através de uso de ácidos graxos essenciais e hidratante corporal, o cuidado com a disposição dos lençóis, de forma a evitar dobras, a utilização de colchão de ar e a aplicação de placas de hidrocoloide nas proeminências ósseas. Conclusão: a prática da prevenção das úlceras por pressão aplicada pelos enfermeiros da unidade de terapia intensiva ocorre sem padronização dos cuidados

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present work is an initiative of undertaking a perspective that values the aspects of the city in its diversity. The one that t intends is to discuss the urbanity starting from the aspect of the image, of the history, and about main point, to value the point of the individual's view that lives the urban space in its more several configurations: the house, the street, the neighborhood, and the city in wider scale. The described historical research defines the city as space of the human accomplishments. When analyzing the moments of the most recent history of the urban life the modernity/post-modernity notions they are explored in the sense of illuminating the wealth, continuity and it breaks of patterns of behavior, and on the other hand, to describe a I overfly in the several times of the city. The prominences of aspects of the archaeology and of the descriptive resource they are related, for its time, the most punctual perspective of the practical research, the instance of the neighborhood, specifically High City and Riverside, configuring an immersion in the daily more punctual of the city, valuing forms of being, aiming the perspective of the personal computer as point-of-view. The images of the city assume the paper of representing the documental about the current features of the urbanity. It is without a doubt that at the present time the photographic image already possesses a paper of prominence it is as research instrument, be as main source for a work on files of photos. The photographic images in the present work possess a prominence place, focusing specific places of the city in the time. Finally, the individual's voice valued under the perspective on as the person's knowledge that inhabits and live the urbanity he/she understands the knowledge of the life in the city and, more than in any other place, a middle where the loss of action models is pointed very easily tends in view the dynamic movement of the practices and renewal of new indications; in the same space in that becomes urgent to build marks starting from which the individual can shimmer the future. And in that space the individual's voice is valued as rich source of information on living the scenery of conflicts of the present time

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This Study inserts in Mathematical Education & Education that search to investigate the (self) formation of formers that gets graduation e pass to graduate others that get graduation and are formers in Mathematical Education. This Is a qualitative search in a perspective from search-formation.The work is formed of four topics. First topic talks about : The self-formation of formers. Second topic: at way of suppositions theorical-methodological from search. Third topic tells over: The life of a former life. Fouth topic A Station called Ubiratan D´Ambrosio created in his reverence and for build all the Knowledge´s Corpus developed by his studies and searches. It´s in sense of come and go from knowledge created at action by mankind to get finality of Transcendency and Survive. Look for to investigate aspects of academical, professional and personal life where are translated in language, thinking and practices oriented for one know-how holistical and transdiciplined in a reflexion, search and the critical it constitute to be a Professor, Teacher, Searcher and Etnomathematic that confered him the merit in 2005 the Prize Félix Klein, that declared Valente (2007), maximum distinction that can receive someone from Mathematical Education. The results point that the narratives of life´s stories are prominences to one re-direction of teach practical in formation´s courses of Mathematical teachers, opening spaces for what the teachers and particularly of Mathematical thinking and take position about your process of formation to be Formers. The Study also given possibilities to propose fourteen stoppages in Station that are beginnings with direction that emerge from studies and searches about the trajectory of life of Professor Ubiratan D´Ambrosio in perspective of re-signify the formative process in education and Mathematical Education

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The sinuses of the posterior wall of the tympanic cavity are formed between the bony ridges, bridges and other osseous prominences, remnants of the tympanum widening process. Anatomical limits and relationships of these sinuses were observed in 100 human temporal bones. Many morphological variabilities were found due to different levels of development of the middle ear posterior wall. The most important sinuses of this complex are the Sinus tympani and the Facial Sinus (Facial recess) seen in all cases. The Lateral tympanic sinus is well-formed in 83% of the cases and the Posterior tympanic sinus in 20% of our series.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The occurrence of morphotypes in Macrobrachium amazonicum males was investigated. Prawns aged 4 to 24 months were taken from 10 aquaculture earthen ponds. Color and spination of right second cheliped were analyzed under a stereomicroscope. Post-orbital and carapace length were measured as well as the length of the cheliped and all limb joints on the right second pereiopods. Four distinct morphotypes were identified: Translucent Claw (TC), Cinnamon Claw (CC), Green Claw 1 (GC1) and Green Claw 2 (GC2). They differed in cheliped morphology and some morphometric relationships. Chelipeds were translucent in TC prawns while in CC they were generally cinnamon-color. Both showed a few spines and some low prominences similar to very small tubercles. GC1 and GC2 showed long moss green chelipeds provided with long and robust spines. However, in GC2, cheliped length was always greater than post-orbital length and the angles of spines on the carpus and propodus were more open, ranging from 51°to 92°, while, in GC1 it varies from 34°to 65°. Cheliped length, the cheliped length/post-orbital length ratio and the spine angle were significantly different among the four morphotypes. A description for the identification of each group is provided and the development of M. amazonicum males is discussed. Each morphotype may play a different role in the population and in the environment in which it lives. Therefore, the identification of morphotypes is advisable for future researches on the biology and culture of M. amazonicum. © 2004 Elsevier B.V. All rights reserved.