998 resultados para COMPACT RADIO-SOURCES
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We have compiled optical and radio astrometric data of the microquasar LS 5039 and derived its proper motion. This, together with the distance and radial velocity of the system, allows us to state that this source is escaping from its own regional standard of rest, with a total systemic velocity of about 150 km/s and a component perpendicular to the galactic plane larger than 100 km/s. This is probably the result of an acceleration obtained during the supernova event that created the compact object in this binary system. We have computed the trajectory of LS 5039 in the past, and searched for OB associations and supernova remnants in its path. In particular, we have studied the possible association between LS 5039 and the supernova remnant G016.8-01.1, which, despite our efforts, remains dubious. We have also discovered and studied an HI cavity in the ISM, which could have been created by the stellar wind of LS 5039 or by the progenitor of the compact object in the system. Finally, in the symmetric supernova explosion scenario, we estimate that at least 17 solar masses were lost in order to produce the high eccentricity observed. Such a mass loss could also explain the observed runaway velocity of the microquasar.
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The possible associations between the microquasars LS 5039 and LS I +61 303 and the EGRET sources 3EG J1824-1514 and 3EG J0241+6103 suggest that microquasars could also be sources of high-energy gamma-rays. In this work, we present a detailed numerical inverse Compton (IC) model, based on a microquasar scenario, that reproduces the high-energy gamma-ray spectra and variability observed by EGRET for the mentioned sources. Our model considers a population of relativistic electrons entrained in a cylindrical inhomogeneous jet that interact through IC scattering with both the radiation and the magnetic fields.
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Intravascular brachytherapy with beta sources has become a useful technique to prevent restenosis after cardiovascular intervention. In particular, the Beta-Cath high-dose-rate system, manufactured by Novoste Corporation, is a commercially available 90Sr 90Y source for intravascular brachytherapy that is achieving widespread use. Its dosimetric characterization has attracted considerable attention in recent years. Unfortunately, the short ranges of the emitted beta particles and the associated large dose gradients make experimental measurements particularly difficult. This circumstance has motivated the appearance of a number of papers addressing the characterization of this source by means of Monte Carlo simulation techniques.
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OBJETIVO: Analisar, retrospectivamente, os resultados da radioterapia externa (RT) combinada a braquiterapia de alta taxa de dose (BATD), adjuvantes à cirurgia para o carcinoma de endométrio. MATERIAIS E MÉTODOS: Avaliamos 141 pacientes tratados com RT e BATD adjuvantes à cirurgia, no período de janeiro de 1993 a janeiro de 2001. RT pélvica foi realizada com dose mediana de 45 Gy, e BATD realizada na dose mediana de 24 Gy, em quatro inserções semanais de 6 Gy. A idade mediana das pacientes foi de 63 anos e a distribuição por estádio clínico (EC) foi: EC I (FIGO), 52,4%; EC II, 13,5%; EC III, 29,8%; EC IV, 4,3%. RESULTADOS: Com seguimento mediano de 53,7 meses, a sobrevida livre de doença (SLD) em cinco anos foi: EC I, 88,0%; EC II, 70,8%; EC III, 55,1%; EC IV, 50,0% (p = 0,0003). A sobrevida global em cinco anos foi: EC I, 79,6%; EC II, 74,0%; EC III, 53,6%; EC IV, 100,0% (p = 0,0062). Fatores que influíram na SLD foram grau histológico e histologia seropapilífera. Dos 33 casos que apresentaram recidiva da doença, em 13 (9,2%) esta ocorreu na pelve, vagina ou cúpula vaginal. RT + BATD do fundo vaginal permitiram o controle da doença em 90,8% dos casos. CONCLUSÃO: A RT exerce papel fundamental no controle loco-regional do câncer de endométrio e permite excelentes taxas de cura nos estádios iniciais. Para os estádios mais avançados, a falha terapêutica tende a ser a distância, sugerindo a necessidade de complementação terapêutica sistêmica, com introdução de novas modalidades de tratamento, em particular a quimioterapia.
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Microquasars are promising candidates to emit high-energy gamma-rays. Moreover, statistical studies show that variable EGRET sources at low galactic latitudes could be associated with the inner spiral arms. The variable nature and the location in the Galaxy of the high-mass microquasars, concentrated in the galactic plane and within 55 degrees from the galactic center, give to these objects the status of likely counterparts of the variable low-latitude EGRET sources. We consider in this work the two most variable EGRET sources at low-latitudes: 3EG J1828+0142 and 3EG J1735-1500, proposing a microquasar model to explain the EGRET data in consistency with the observations at lower energies (from radio frequencies to soft gamma-rays) within the EGRET error box.
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OBJECTIVE: To identify and quantify sources of variability in scores on the speech, spatial, and qualities of hearing scale (SSQ) and its short forms among normal-hearing and hearing-impaired subjects using a French-language version of the SSQ. DESIGN: Multi-regression analyses of SSQ scores were performed using age, gender, years of education, hearing loss, and hearing-loss asymmetry as predictors. Similar analyses were performed for each subscale (Speech, Spatial, and Qualities), for several SSQ short forms, and for differences in subscale scores. STUDY SAMPLE: One hundred normal-hearing subjects (NHS) and 230 hearing-impaired subjects (HIS). RESULTS: Hearing loss in the better ear and hearing-loss asymmetry were the two main predictors of scores on the overall SSQ, the three main subscales, and the SSQ short forms. The greatest difference between the NHS and HIS was observed for the Speech subscale, and the NHS showed scores well below the maximum of 10. An age effect was observed mostly on the Speech subscale items, and the number of years of education had a significant influence on several Spatial and Qualities subscale items. CONCLUSION: Strong similarities between SSQ scores obtained across different populations and languages, and between SSQ and short forms, underline their potential international use.
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(ENGLISH VERSION BELOW) En 1780, le médecin Jean-André Venel fonde à Orbe, dans le canton de Vaud, le premier institut orthopédique connu dans le monde, proposant une version clinique d'un savoir-faire médical ancestral. A travers des sources qui réactualisent les travaux consacrés à Venel, cet article retrace les origines de son institution et de sa pensée médicale, dans un contexte de production et de diffusion d'un savoir particulier en termes de technique du corps et de médecine de l'enfant. Revisitant la figure légendaire - ou mythique ? - de ce que l'histoire de la médecine a retenu comme étant le « père de l'orthopédie », l'article s'interroge par la même occasion sur les conditions d'émergence d'une spécialité médicale au sortir de l'Ancien Régime, et de son impact dans les premières décennies du XIXe siècle. In 1780, the physician Jean-André Venel creates in Orbe (canton of Vaud) the first orthopedic institute of the world, offering a clinical version of an ancient medical savoir-faire. By using sources that enable us to update the scholarship on Venel, this article traces the origins of his institute and of his medical thought, in the context of the production and diffusion of a specialized knowledge on the body and on children. With this new perspective on the legendary, if not mythical, figure, whom the history of medicine has canonized as the "father of orthopedia", this article also examines the conditions of emergence of a medical specialization at the end of the Ancien Régime and its impact in the first decades of the nineteenth century.
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The Faculty of Business and Communication recently started an internationalization process that, in two year’s time, will allow all undergraduate students (studying Journalism, Audiovisual Communication, Advertising and Public Relations, Business and Marketing) to take 25% of their subjects in English using CLIL methodology. Currently, Journalism is the degree course with the greatest percentage of CLIL subjects, for example Current Affairs Workshop, a subject dedicated to analyzing current news using opinion genres. Moreover, because of the lack of other subjects offered in English, ERASMUS students have to take some journalism subjects in order to complete their international passport, and one of the classes they choose is the Current Affairs Workshop. The aim of this paper is to explore how CLIL methodology can be useful for learning journalistic opinion genres (chat-shows, discussions and debates) in a subject where Catalan Communication students –with different levels of English- share their knowledge with European students of other social disciplines. Students work in multidisciplinary groups in which they develop real radio and TV programs, adopting all the roles (moderator, technician, producer and participants), analyzing daily newspapers and other sources to create content, based on current affairs. This paper is based on the participant observation of the lecturers of the subject, who have designed different activities related to journalistic genres, where students can develop their skills according to the role they play in every assignment. Examples of successful lessons will be given, in addition to the results of the course: both positive and negative. Although the objective of the course is to examine professional routines related to opinion genres, and students are not directly graded on their level of English, the Catalan students come to appreciate how they finally overcome their fear of working in a foreign language. This is a basic result of their experience.
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Given their central role in mercury (Hg) excretion and suitability as reservoirs, bird feathers are useful Hg biomonitors. Nevertheless, the interpretation of Hg concentrations is still questioned as a result of a poor knowledge of feather physiology and mechanisms affecting Hg deposition. Given the constraints of feather availability to ecotoxicological studies, we tested the effect of intra-individual differences in Hg concentrations according to feather type (body vs. flight feathers), position in the wing and size (mass and length) in order to understand how these factors could affect Hg estimates. We measured Hg concentration of 154 feathers from 28 un-moulted barn owls (Tyto alba), collected dead on roadsides. Median Hg concentration was 0.45 (0.076-4.5) mg kg(-1) in body feathers, 0.44 (0.040-4.9) mg kg(-1) in primary and 0.60 (0.042-4.7) mg kg(-1) in secondary feathers, and we found a poor effect of feather type on intra-individual Hg levels. We also found a negative effect of wing feather mass on Hg concentration but not of feather length and of its position in the wing. We hypothesize that differences in feather growth rate may be the main driver of between-feather differences in Hg concentrations, which can have implications in the interpretation of Hg concentrations in feathers. Finally, we recommend that, whenever possible, several feathers from the same individual should be analysed. The five innermost primaries have lowest mean deviations to both between-feather and intra-individual mean Hg concentration and thus should be selected under restrictive sampling scenarios.
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Determining the appropriate level of integration is crucial to realizing value from acquisitions. Most prior research assumes that higher integration implies the removal of autonomy from target managers, which in turn undermines the functioning of the target firm if it entails unfamiliar elements for the acquirer. Using a survey of 86 acquisitions to obtain the richness of detail necessary to distinguish integration from autonomy, the authors argue and find that integration and autonomy are not the opposite ends of a single continuum. Certain conditions (e.g., when complementarity rather than similarity is the primary source of synergy) lead to high levels of both integration and autonomy. In addition, similarity negatively moderates the relationship between complementarity and autonomy when the target offers both synergy sources. In contrast, similarity does not moderate the link between complementarity and integration. The authors' findings advance scholarly understanding about the drivers of implementation strategy and in particular the different implementation strategies acquiring managers deploy when they attempt to leverage complementarities, similarities, or both.
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En collectant plus de deux millions de tweets reliés au centenaire de la Grande Guerre, de nombreuses questions méthodologiques se sont posées, interrogeant par exemple la notion de corpus, les relations entre historien.ne.s et archivistes, le traitement du passé à une ère de données massives. Cette intervention se penche sur l'une de ces questions: comment fonder une recherche sur des sources primaires en flux? Comment résoudre la contradiction inhérente entre l'archive, réputée figée, et les données nées numériques qui sont émises en flux?
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Here we discuss two consecutive MERLIN observations of the X-ray binary LS I +61° 303 . The first observation shows a double-sided jet extending up to about 200 AU on both sides of a central source. The jet shows a bent S-shaped structure similar to the one displayed by the well-known precessing jet of SS 433 . The precession suggested in the first MERLIN image becomes evident in the second one, showing a one-sided bent jet significantly rotated with respect to the jet of the day before. We conclude that the derived precession of the relativistic (beta=0.6) jet explains puzzling previous VLBI results. Moreover, the fact that the precession is fast could be the explanation of the never understood short term (days) variability of the associated gamma-ray source 2CG 135+01 / 3EG J0241+6103