2,294 research outputs found

    First detection of CF+ towards a high-mass protostar

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    We report the first detection of the J = 1 - 0 (102.6 GHz) rotational lines of CF+ (fluoromethylidynium ion) towards CygX-N63, a young and massive protostar of the Cygnus X region. This detection occurred as part of an unbiased spectral survey of this object in the 0.8-3 mm range, performed with the IRAM 30m telescope. The data were analyzed using a local thermodynamical equilibrium model (LTE model) and a population diagram in order to derive the column density. The line velocity (-4 km s-1) and line width (1.6 km s-1) indicate an origin from the collapsing envelope of the protostar. We obtain a CF+ column density of 4.10e11 cm-2. The CF+ ion is thought to be a good tracer for C+ and assuming a ratio of 10e-6 for CF+/C+, we derive a total number of C+ of 1.2x10e53 within the beam. There is no evidence of carbon ionization caused by an exterior source of UV photons suggesting that the protostar itself is the source of ionization. Ionization from the protostellar photosphere is not efficient enough. In contrast, X-ray ionization from the accretion shock(s) and UV ionization from outflow shocks could provide a large enough ionizing power to explain our CF+ detection. Surprisingly, CF+ has been detected towards a cold, massive protostar with no sign of an external photon dissociation region (PDR), which means that the only possibility is the existence of a significant inner source of C+. This is an important result that opens interesting perspectives to study the early development of ionized regions and to approach the issue of the evolution of the inner regions of collapsing envelopes of massive protostars. The existence of high energy radiations early in the evolution of massive protostars also has important implications for chemical evolution of dense collapsing gas and could trigger peculiar chemistry and early formation of a hot core.Comment: 6 page

    Internamentos Compulsivos: revisão da casuística dos HUC e HIP no triénio 2006-2008.

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    ão obstante terem passado mais de 10 anos sobre a publicação da Lei de Saúde Mental, o intenso debate e reflexão ocorridos não foram acompanhados por publicação, igualmente profusa, de investigação clínica sobre a epidemiologia dos internamentos compulsivos. Os autores procuraram caracterizar o arquétipo do doente submetido a internamento involuntário em Portugal, apreciando variáveis demográficas, clínicas e legais. Para esse fim, conduziu-se um estudo retrospectivo dos internamentos compulsivos ocorridos entre 2006 e 2008 em dois hospitais: os Hospitais da Universidade de Coimbra (HUC) e o Hospital Infante D. Pedro – Aveiro (HIP). Uma amostra de 384 internamentos foi recolhida e caracterizada, apresentando-se resultados desta investigação e discussão dos dados obtidos

    Efeito da época de semeadura sobre a qualidade da semente de soja no Estado de Mato Grosso.

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    Phase-transition-like properties of double-beam optical tweezers

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    We report on double-beam optical tweezers that undergo previously unknown phase-transition-like behavior resulting in the formation of more optical traps than the number of beams used to create them. We classify the optical force fields which produce multiple traps for a double-beam system including the critical behavior. This effect is demonstrated experimentally in orthogonally polarized (noninterfering) dual-beam optical tweezers for a silica particle of 2.32  μm diameter. Phase transitions of multiple beam trapping systems have implications for hopping rates between traps and detection of forces between biomolecules using dual-beam optical tweezers. It is an example of a novel dynamic system with multiple states where force fields undergo a series of sign inversions as a function of parameters such as size and beam separation

    The W43-MM1 mini-starburst ridge, a test for star formation efficiency models

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    Context: Star formation efficiency (SFE) theories are currently based on statistical distributions of turbulent cloud structures and a simple model of star formation from cores. They remain poorly tested, especially at the highest densities. Aims: We investigate the effects of gas density on the SFE through measurements of the core formation efficiency (CFE). With a total mass of 2×104\sim2\times10^4 M_\odot, the W43-MM1 ridge is one of the most convincing candidate precursor of starburst clusters and thus one of the best place to investigate star formation. Methods: We used high-angular resolution maps obtained at 3 mm and 1 mm within W43-MM1 with the IRAM Plateau de Bure Interferometer to reveal a cluster of 11 massive dense cores (MDCs), and, one of the most massive protostellar cores known. An Herschel column density image provided the mass distribution of the cloud gas. We then measured the 'instantaneous' CFE and estimated the SFE and the star formation rate (SFR) within subregions of the W43-MM1 ridge. Results: The high SFE found in the ridge (\sim6% enclosed in \sim8 pc3^3) confirms its ability to form a starburst cluster. There is however a clear lack of dense cores in the northern part of the ridge, which may be currently assembling. The CFE and the SFE are observed to increase with volume gas density while the SFR steeply decreases with the virial parameter, αvir\alpha_{vir}. Statistical models of the SFR may well describe the outskirts of the W43-MM1 ridge but struggle to reproduce its inner part, which corresponds to measurements at low αvir\alpha_{vir}. It may be that ridges do not follow the log-normal density distribution, Larson relations, and stationary conditions forced in the statistical SFR models.Comment: 13 pages, 7 figures. Accepted by A&

    Diversidade de homológos do gene codificador da proteína alergênica alt a 1 em isolados de Alternaria associados com aliáceas no Brasil.

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    No presente trabalho foi realizado um estudo da diversidade de isolados de Alternaria de aliáceas no Brasil usnado informações genéticas derivadas do gene CTAB.Resumo 1075. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves

    Abcesso Prostático

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    O abcesso da próstata é actualmente uma entidade pouco frequente, resultado de uma melhoria na terapêutica antibiótica. No entanto deve ser considerado em doentes com factores de risco (infecções urinárias complicadas) que no decurso de um quadro infeccioso, apresentam agravamento marcado da sintomatologia ou resposta inadequada à terapêutica. Apresentamos um caso clínico de um doente de 47 anos com diabetes mellitus não controlada, cujo abcesso prostático foi tratado com antibioterapia sistémica, associada a drenagem transrectal ecodirigida
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