16,888 research outputs found

    The ionizing sources of luminous compact HII regions in the RCW106 and RCW122 clouds

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    Given the rarity of young O star candidates, compact HII regions embedded in dense molecular cores continue to serve as potential sites to peer into the details of high-mass star formation. To uncover the ionizing sources of the most luminous and compact HII regions embedded in the RCW106 and RCW122 giant molecular clouds, known to be relatively nearby (2-4 kpc) and isolated, thus providing an opportunity to examine spatial scales of a few hundred to a thousand AU in size. High spatial resolution (0.3"), mid-infrared spectra (R=350), including the fine structure lines [ArIII] and [NeII], were obtained for four luminous compact HII regions, embedded inside the dense cores within the RCW106 and RCW122 molecular cloud complexes. At this resolution, these targets reveal point-like sources surrounded by nebulosity of different morphologies, uncovering details at spatial dimensions of <1000AU. The point-like sources display [ArIII] and [NeII] lines - the ratios of which are used to estimate the temperature of the embedded sources. The derived temperatures are indicative of mid-late O type objects for all the sources with [ArIII] emission. Previously known characteristics of these targets from the literature, including evidence of disk or accretion suggest that the identified sources may grow more to become early-type O stars by the end of the star formation process

    Vaccines in Congenital Toxoplasmosis: Advances and Perspectives

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    Congenital toxoplasmosis has a high impact on human disease worldwide, inducing serious consequences from fetus to adulthood. Despite this, there are currently no human vaccines available to prevent this infection. Most vaccination studies against Toxoplasma gondii infection used animal models in which the infection was established by exogenous inoculation. Here, we review recent research on potential T. gondii vaccines using animal models in which infection was congenitally established. Endeavors in this field have so far revealed that live or subunit vaccines previously found to confer protection against extrinsically established infections can also protect, at least partially, from vertically transmitted infection. Nevertheless, there is no consensus on the more adequate immune response to protect the host and the fetus in congenital infection. Most of the vaccination studies rely on the assessment of maternal systemic immune responses, quantification of parasitic loads in the fetuses, and survival indexes and/or brain parasitic burden in the neonates. More research must be carried out not only to explore new vaccines but also to further study the nature of the elicited immune protection at the maternal-fetal interface. Particularly, the cellular and molecular effector mechanisms at the maternal-fetal interface induced by immunization remain poorly characterized. Deeper knowledge on the immune response at this specific location will certainly help to refine the vaccine-induced immunity and, consequently, to provide the most effective and safest protection against T. gondii vertical infection.This work was supported by the Applied Molecular Biosciences Unit-UCIBIO, which is financed by national funds from FCT (UIDP/04378/2020 and UIDB/04378/2020). AC was supported by FCT Individual CEEC 2017 Assistant Researcher Grant 352 CEECIND/01514/2017

    A traça-do-tomateiro (Tuta absoluta) em Rondônia: ocorrência, danos e indicações de controle.

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    Este trabalho tem como objetivo evidenciar as características da traça do tomateiro e indicar ações de manejo que assegurem a viabilidade da produção de tomate no Estado de Rondônia.bitstream/item/79852/1/FOL-6126-0001.pd

    Eventos: ferramentas estratégicas de comunicação.

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    A Comunicação Organizacional na Empresa Brasileira de Pesquisa Agropecuária (Embrapa) é definida, em sua política, como um processo gerencial permanente e sistêmico, que integra as atividades de relacionamento entre organização e públicos, tendo como objetivo criar e manter os fluxos de informação. Nesse contexto a promoção e realização de eventos é uma das ferramentas de comunicação usadas estrategicamente com o objetivo de criar e reforçar relacionamentos entre empresa e públicos de interesse, bem como apoiar o processo de transferência de tecnologia na Embrapa

    Future dynamics in f(R) theories

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    The f(R)f(R) gravity theories provide an alternative way to explain the current cosmic acceleration without invoking dark energy matter component. However, the freedom in the choice of the functional forms of f(R)f(R) gives rise to the problem of how to constrain and break the degeneracy among these gravity theories on theoretical and/or observational grounds. In this paper to proceed further with the investigation on the potentialities, difficulties and limitations of f(R)f(R) gravity, we examine the question as to whether the future dynamics can be used to break the degeneracy between f(R)f(R) gravity theories by investigating the future dynamics of spatially homogeneous and isotropic dust flat models in two f(R)f(R) gravity theories, namely the well known f(R)=R+αRnf(R) = R + \alpha R^{n} gravity and another by A. Aviles et al., whose motivation comes from the cosmographic approach to f(R)f(R) gravity. To this end we perform a detailed numerical study of the future dynamic of these flat model in these theories taking into account the recent constraints on the cosmological parameters made by the Planck team. We show that besides being powerful for discriminating between f(R)f(R) gravity theories, the future dynamics technique can also be used to determine the fate of the Universe in the framework of these f(R)f(R) gravity theories. Moreover, there emerges from our numerical analysis that if we do not invoke a dark energy component with equation-of-state parameter ω<1\omega < -1 one still has dust flat FLRW solution with a big rip, if gravity deviates from general relativity via f(R)=R+αRnf(R) = R + \alpha R^n . We also show that FLRW dust solutions with f<0f''<0 do not necessarily lead to singularity.Comment: 12 pages, 8 figures. V2: Generality and implications of the results are emphasized, connection with the recent literature improved, typos corrected, references adde
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