189 research outputs found

    The Exoplanet Census: A General Method, Applied to Kepler

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    We develop a general method to fit the planetary distribution function (PLDF) to exoplanet survey data. This maximum likelihood method accommodates more than one planet per star and any number of planet or target star properties. Application to \Kepler data relies on estimates of the efficiency of discovering transits around Solar type stars by Howard et al. (2011). These estimates are shown to agree with theoretical predictions for an ideal transit survey. Using announced \Kepler planet candidates, we fit the PLDF as a joint powerlaw in planet radius, down to 0.5 R_Eart, and orbital period, up to 50 days. The estimated number of planets per star in this sample is ~ 0.7 --- 1.4, where the broad range covers systematic uncertainties in the detection efficiency. To analyze trends in the PLDF we consider four planet samples, divided between shorter and longer periods at 7 days and between large and small radii at 3 R_Earth. At longer periods, the size distribution of the small planets, with index \alpha = -1.2 \pm 0.2 steepens to \alpha = -2.0 \pm 0.2 for the larger planet sample. For shorter periods, the opposite is seen: smaller planets follow a steep powerlaw, \alpha = -1.9 \pm 0.2 that is much shallower, \alpha = -0.7 \pm 0.2 at large radii. The observed deficit of intermediate-sized planets at the shortest periods may arise from the evaporation and sublimation of Neptune and Saturn-like planets. If the trend and explanation hold, it would be spectacular observational confirmation of the core accretion and migration hypotheses, and allow refinement of these theories.Comment: Submitted to Ap

    ATUAÇÃO DE ASSISTENTES SOCIAIS EM NÚCLEO DE PRÁTICA JURÍDICA: A EXPERIÊNCIA NA REESTRUTURAÇÃO DO CENTRO UNIVERSITÁRIO UNIBRASIL

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    Resumo Este artigo tem como finalidade, apresentar o processo de reconstrução do setor de Serviço Social durante a reestruturação do Núcleo de Prática Jurídica (NPJ) Desembargador Cordeiro Clève do Centro Universitário Autônomo do Brasil – Unibrasil, localizado na cidade de Curitiba/Paraná. Entende-se que, por ser um processo, é fundamental constante revisitação em seu projeto de intervenção inicial. Para essa discussão, o presente trabalho divide-se em três partes: no primeiro momento explicita-se brevemente a atuação do referido setor no NPJ e a ligação com o Curso de Serviço Social do UNIBRASIL. Aponta-se a construção e sistematização da prática profissional e posteriormente são relatadas as demandas e atendimentos realizados no NPJ, especificamente, a atuação do Serviço Social. Por fim, destacam-se as considerações finais e as primeiras impressões sobre a atuação da categoria no NPJ

    Release of Small RNA-containing Exosome-like Vesicles from the Human Filarial Parasite Brugia malayi

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    Lymphatic filariasis (LF) is a socio-economically devastating mosquito-borne Neglected Tropical Disease caused by parasitic filarial nematodes. The interaction between the parasite and host, both mosquito and human, during infection, development and persistence is dynamic and delicately balanced. Manipulation of this interface to the detriment of the parasite is a promising potential avenue to develop disease therapies but is prevented by our very limited understanding of the host-parasite relationship. Exosomes are bioactive small vesicles (30–120 nm) secreted by a wide range of cell types and involved in a wide range of physiological processes. Here, we report the identification and partial characterization of exosome-like vesicles (ELVs) released from the infective L3 stage of the human filarial parasite Brugia malayi. Exosome-like vesicles were isolated from parasites in culture media and electron microscopy and nanoparticle tracking analysis were used to confirm that vesicles produced by juvenile B. malayi are exosome-like based on size and morphology. We show that loss of parasite viability correlates with a time-dependent decay in vesicle size specificity and rate of release. The protein cargo of these vesicles is shown to include common exosomal protein markers and putative effector proteins. These Brugia-derived vesicles contain small RNA species that include microRNAs with host homology, suggesting a potential role in host manipulation. Confocal microscopy shows J774A.1, a murine macrophage cell line, internalize purified ELVs, and we demonstrate that these ELVs effectively stimulate a classically activated macrophage phenotype in J774A.1. To our knowledge, this is the first report of exosome-like vesicle release by a human parasitic nematode and our data suggest a novel mechanism by which human parasitic nematodes may actively direct the host responses to infection. Further interrogation of the makeup and function of these bioactive vesicles could seed new therapeutic strategies and unearth stage-specific diagnostic biomarkers

    The Effect of In Vitro Cultivation on the Transcriptome of Adult Brugia malayi

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    Infections with filarial worms cause serious physical impairment and affect tens of millions of people in tropical and subtropical countries. To better understand the biology and phar- macology of these parasites, Brugia malayi is often used as a model. This parasite can be maintained in the laboratory in Mongolian jirds, enabling researchers to test drugs in vivoand in vitro, among other studies. The effects of removing worms from their hosts and cul- turing them may affect many aspects of their physiology, including response to drugs, but the extent to which the worms undergo changes during culture has remained unknown. Using deep RNA sequencing and bioinformatics tools, we examined the global transcriptomic profile of B. malayi females at four different time points over 5 days in culture. Focusing on genes that are differentially expressed at various time points, we observed a general perturbation of the expression profile between dissection from the host and receipt after shipment. The expression of several genes remained changed at the end of the experi- ment, after 5 days under controlled conditions; in particular, genes encoding cuticle colla- gens were prominently represented and strongly overexpressed
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