1,065 research outputs found

    Multiple and Precessing Collimated Outflows in the Planetary Nebula IC 4634

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    With its remarkable double-S shape, IC 4634 is an archetype of point-symmetric planetary nebulae (PN). In this paper, we present a detailed study of this PN using archival HST WFPC2 and ground-based narrow-band images to investigate its morphology, and long-slit spectroscopic observations to determine its kinematics and to derive its physical conditions and excitation. The data reveal new structural components, including a distant string of knots distributed along an arc-like feature 40"-60" from the center of the nebula, a skin of enhanced [O III]/H-alpha ratio enveloping the inner shell and the double-S feature, and a triple-shell structure. The spatio-kinematical study also finds an equatorial component of the main nebula that is kinematically independent from the bright inner S-shaped arc. We have investigated in detail the bow shock-like features in IC 4634 and found that their morphological, kinematical and emission properties are consistent with the interaction of a collimated outflow with surrounding material. Indeed, the morphology and kinematics of some of these features can be interpreted using a 3D numerical simulation of a collimated outflow precessing at a moderate, time-dependent velocity. Apparently, IC 4634 has experienced several episodes of point-symmetric ejections oriented at different directions with the outer S-shaped feature being related to an earlier point-symmetric ejection and the outermost arc-like string of knots being the relic of an even much earlier point-symmetric ejection. There is tantalizing evidence that the action of these collimated outflows has also taken part in the shaping of the innermost shell and inner S-shaped arc of IC 4634.Comment: 16 pages, 11 figures, accepted for publication in The Astrophysical Journa

    Neighborhood properties of complex networks

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    A concept of neighborhood in complex networks is addressed based on the criterion of the minimal number os steps to reach other vertices. This amounts to, starting from a given network R1R_1, generating a family of networks R,=2,3,...R_\ell, \ell=2,3,... such that, the vertices that are \ell steps apart in the original R1R_1, are only 1 step apart in RR_\ell. The higher order networks are generated using Boolean operations among the adjacency matrices MM_\ell that represent RR_\ell. The families originated by the well known linear and the Erd\"os-Renyi networks are found to be invariant, in the sense that the spectra of MM_\ell are the same, up to finite size effects. A further family originated from small world network is identified

    Streblidae (Diptera: pupipara) ectoparásitos de murciélagos, en las tierras bajas del Parque Nacional Darién, provincia de Darién, Panamá

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    En este trabajo Artibeus jamaicensis, A. phaeotis, Carollia castanea, C. perspicillata, Chiroderma salvini, Phillostomus hastatus, Sturnira lilium y Uroderma bilobatum son las especies de murciélagos donde la diversidad ectoparasítica estuvo representada por 14 especies de Streblidae; mientras que Artibeus lituratus, A. watsoni y Vampiressa pusilla forman el grupo de los no parasitados. El parásito Trichobius joblingi resultó ser el Streblidae más abundante (53 individuos). Reportamos por primera vez para Panamá a Artibeus phaeotis como hospedero de Neotrichobius stenopterus. Las especies Mastoptera guimaraesi, Speiseria ambigua, Strebla mirabilis, Trichobius longipes y T. sparsus son especies de Streblidae reportadas por primera vez para la Provincia de Darié

    STREBLIDAE (DIPTERA: PUPIPARA) ECTOPARÁSITOS DE MURCIÉLAGOS, EN LAS TIERRAS BAJAS DEL PARQUE NACIONAL DARIÉN, PROVINCIA DE DARIÉN, PANAMA.

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      In this work Artibeus jamaicensis, A. phaeotis, Carollia castanea, C. perspicillata, Chiroderma salvini, Phillostomus hastatus, Sturnira lilium and Uroderma bilobatum are the species of parasited bats by Streblidae, while Artibeus lituratus, A. watsoni and Vampiressa pusilla form the group of the non-parasited bats. Trichobius joblingi is the most abundant Streblidae (53 specimens). We reported for first time in Panama the species Artibeus phaeotis as host for the Neotrichobius stenopterus. Mastoptera guimaraesi, Speiseira ambigua, Strebla mirabilis, Trichobius longipes and T. sparsus are the species of Streblidae reported in the province of Darien.  En este trabajo Artibeus jamaicensis, A. phaeotis, Carollia castanea, C. perspicillata, Chiroderma salvini, Phillostomus hastatus, Sturnira lilium y Uroderma bilobatum son las especies de murciélagos donde la diversidad ectoparasítica estuvo representada por 14 especies de Streblidae; mientras que Artibeus lituratus, A. watsoni y Vampiressa pusilla forman el grupo de los no parasitados. El parásito Trichobius joblingi resultó ser el Streblidae más abundante (53 individuos). Reportamos por primera vez para Panamá a Artibeus phaeotis como hospedero de Neotrichobius stenopterus. Las especies Mastoptera guimaraesi, Speiseria ambigua, Strebla mirabilis, Trichobius longipes y T. sparsus son especies de Streblidae reportadas por primera vez para la Provincia de Darién

    Avaliação de risco em mioloma múltiplo: resultados preliminares do grupo brasileiro de estudos de mieloma

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    The Durie/Salmon staging system continues to be used worldwide in patients with multiple myeloma. However, in recent years, new systems have been proposed. The International Myeloma Working Group performed a retrospective study with 11,179 patients and proposed an "International Staging System" utilizing serum levels of â2 microglobulin and albumin. In addition, current research has focused on the usefulness of cytogenetic and molecular data as prognostic factors. These data suggest that these parameters are powerful discriminators of a poor prognostic group of myeloma patients. Indeed, these prognostic indexes have been utilized in clinical trials, with interesting and encouraging results.O esquema de Durie / Salmon continua a ser utilizado para estadiar os pacientes com mieloma múltiplo. Recentemente, um novo sistema mais simples e eficaz foi proposto. O "International Myeloma Working Group" realizou um estudo retrospectivo com 11.179 pacientes e a partir destes dados propôs a criação de um "International Staging System (ISS)" utilizando os níveis séricos de ß2 microglobulina e de albumina ao diagnóstico. Além do ISS a pesquisa está voltada para identificar alterações citogenéticas e moleculares que se correlacionem com o prognóstico no mieloma múltiplo. Estes fatores prognósticos têm sido utilizados para estratificar pacientes em ensaios clínicos com resultados promissores

    Avaliação de risco em mioloma múltiplo: resultados preliminares do grupo brasileiro de estudos de mieloma

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    The Durie/Salmon staging system continues to be used worldwide in patients with multiple myeloma. However, in recent years, new systems have been proposed. The International Myeloma Working Group performed a retrospective study with 11,179 patients and proposed an "International Staging System" utilizing serum levels of â2 microglobulin and albumin. In addition, current research has focused on the usefulness of cytogenetic and molecular data as prognostic factors. These data suggest that these parameters are powerful discriminators of a poor prognostic group of myeloma patients. Indeed, these prognostic indexes have been utilized in clinical trials, with interesting and encouraging results.O esquema de Durie / Salmon continua a ser utilizado para estadiar os pacientes com mieloma múltiplo. Recentemente, um novo sistema mais simples e eficaz foi proposto. O "International Myeloma Working Group" realizou um estudo retrospectivo com 11.179 pacientes e a partir destes dados propôs a criação de um "International Staging System (ISS)" utilizando os níveis séricos de ß2 microglobulina e de albumina ao diagnóstico. Além do ISS a pesquisa está voltada para identificar alterações citogenéticas e moleculares que se correlacionem com o prognóstico no mieloma múltiplo. Estes fatores prognósticos têm sido utilizados para estratificar pacientes em ensaios clínicos com resultados promissores.30suppl 26

    Estudo de seguimento por dois anos de idosos residentes em São Paulo, Brasil: metodologia e resultados preliminares

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    INTRODUCTION: Previous cross-sectional studies have shown a high prevalence of chronic disease and disability among the elderly. Given Brazil s rapid aging process and the obvious consequences of the growing number of old people with chronic diseases and associated disabilities for the provision of health services, a need was felt for a study that would overcome the limitations of cross-sectional data and shed some light on the main factors determining whether a person will live longer and free of disabling diseases, the so-called successful aging. The methodology of the first follow-up study of elderly residents in Brazil is presented. METHOD: The profile of the initial cohort is compared with previous cross-sectional data and an in-depth analysis of nonresponse is carried out in order to assess the validity of future longitudinal analysis. The EPIDOSO ( Epidemiologia do Idoso ) Study conducted a two-year follow-up of 1,667 elderly people (65+), living in S. Paulo. The study consisted of two waves, each consisting of household, clinical, and biochemical surveys. RESULTS AND CONCLUSIONS: In general, the initial cohort showed a similar profile to previous cross-sectional samples in S. Paulo. There was a majority of women, mostly widows, living in multigenerational households, and a high prevalence of chronic illnesses, psychiatric disturbances, and physical disabilities. Despite all the difficulties inherent in follow-up studies, there was a fairly low rate of nonresponse to the household survey after two years, which did not actually affect the representation of the cohort at the final household assessment, making unbiased longitudinal analysis possible. Concerning the clinical and blood sampling surveys, the respondents tended to be younger and less disabled than the nonrespondents, limiting the use of the clinical and laboratory data to longitudinal analysis aimed at a healthier cohort. It is worth mentioning that gender, education, family support, and socioeconomic status were not important determinants of nonresponse, as is often the case.INTRODUÇÃO: Estudos transversais recentes mostraram alta prevalência de doenças crônicas e incapacidades físicas entre idosos. Considerando o rápido processo de envelhecimento do Brasil e as conseqüências que esse aumento de idosos com doenças crônicas e incapacidades associadas acarretará para o sistema de saúde, fazia-se necessário estudo que pudesse superar as limitações dos dados transversais, permitindo determinar quais os fatores determinantes de uma vida longa e livre de doenças incapacitantes, o chamado envelhecimento bem sucedido. É apresentada a metodologia do primeiro estudo epidemiológico longitudinal com idosos residentes na comunidade, no Brasil. MÉTODO: O perfil do cohorte inicial é comparado com dados de estudos anteriores a com o perfil dos não respondentes para avaliar a validade de análises longitudinais futuras.O projeto EPIDOSO (Epidemiologia do Idoso) seguiu por dois anos 1.667 idosos (65+), residentes em São Paulo. Consistiu de duas ondas, cada qual com três inquéritos: domiciliar, clínico e laboratorial. RESULTADOS E CONCLUSÕES: O perfil da população não diferiu de estudos anteriores, mostrando maioria de mulheres, viúvas, vivendo em domicílios multigeracionais, com uma alta prevalência de doenças crônicas, distúrbios psiquiátricos e incapacidades físicas. A despeito de todas as dificuldades inerentes a um estudo longitudinal, o grupo de não-respondentes ao segundo inquérito domiciliar não diferiu significativamente dos respondentes, assegurando análises longitudinais livres desse tipo de viés. Em relação aos inquéritos clínico e laboratorial, os não-respondentes mostraram-se mais velhos e mais incapacitados que os respondentes, limitando o uso dos dados clínicos e laboratoriais a análises pertinentes a uma cohorte mais jovem e saudável. Sexo, educação, apoio familiar e nível socioeconômico não influenciaram de forma significativa a taxa de não - resposta, ao contrário do que se costuma verificar.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

    When non-activists care: group efficacy mediates the effect of social identification and perceived instability on the legitimacy of collective action

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    In recent years, multiple social movements have emerged around the world. In addition, public surveys indicate the highest recorded levels of support for protest. In this context of acceptance of collective action, we examine the role of non-activists in the legitimacy of social movements, as this ‘passive’ support can contribute to social change. Given that antecedents of legitimacy have been neglected in the literature, we carried out a survey (N = 605) among a general sample of the population in Chile to shed light on this issue. We found that social identification with movements and perceived instability predicted the perceived legitimacy of protests by social movements, and that both variables had only indirect effects, through group efficacy. This suggests that perceiving social movements as able to achieve success can lead non-activists to perceive their actions as legitimate, highlighting the importance to movements of being seen to be effective
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