843 research outputs found

    acreg:Arbitrary Correlation Regression

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    We present acreg, a new command that implements the arbitrary clustering correction of standard errors proposed in Colella et al. (2019, IZA discussion paper 12584). Arbitrary here refers to the way observational units are correlated with each other: we impose no restrictions so that our approach can be used with a wide range of data. The command accommodates both cross-sectional and panel databases and allows the estimation of ordinary least-squares and two-stage least-squares coefficients, correcting standard errors in three environments: in a spatial setting using units’ coordinates or distance between units, in a network setting starting from the adjacency matrix, and in a multiway clustering framework taking multiple clustering variables as input. Distance and time cutoffs can be specified by the user, and linear decays in time and space are also optional

    acreg: Arbitrary correlation regression

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    We present acreg, a new command that implements the arbitrary clustering correction of standard errors proposed in Colella et al. (2019, IZA discussion paper 12584). Arbitrary here refers to the way observational units are correlated with each other: we impose no restrictions so that our approach can be used with a wide range of data. The command accommodates both cross-sectional and panel databases and allows the estimation of ordinary least-squares and two-stage least-squares coefficients, correcting standard errors in three environments: in a spatial setting using units’ coordinates or distance between units, in a network setting starting from the adjacency matrix, and in a multiway clustering framework taking multiple clustering variables as input. Distance and time cutoffs can be specified by the user, and linear decays in time and space are also optional

    Feline lungworms unlock a novel mode of parasite transmission.

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    Snail-borne lungworms exert an enormous toll on the health and welfare of animals and humans. Of these parasites, Aelurostrongylus abstrusus and Troglostrongylus brevior affect the respiratory tract of felids. These lungworms share both the ecological niche and the species of snail (Helix aspersa) acting as intermediate host. Recently, the ability of H. aspersa to shed infective third-stage larvae (L3s) of A. abstrusus and T. brevior in the environment has been demonstrated, matching previous knowledge of mode of transmission of zoonotic lungworms. Here, we evaluated, for the first time, the ability of A. abstrusus and T. brevior L3s to infect new, susceptible snail hosts following their release from experimentally infected molluscs, and refer to this novel route of parasite transmission as intermediesis. The implications of snail-to-snail transmission in the epidemiology of snail-borne diseases are also discussed.This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/srep1310

    Feline lungworms unlock a novel mode of parasite transmission

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    Snail-borne lungworms exert an enormous toll on the health and welfare of animals and humans. Of these parasites, Aelurostrongylus abstrusus and Troglostrongylus brevior affect the respiratory tract of felids. These lungworms share both the ecological niche and the species of snail (Helix aspersa) acting as intermediate host. Recently, the ability of H. aspersa to shed infective third-stage larvae (L3s) of A. abstrusus and T. brevior in the environment has been demonstrated, matching previous knowledge of mode of transmission of zoonotic lungworms. Here, we evaluated, for the first time, the ability of A. abstrusus and T. brevior L3s to infect new, susceptible snail hosts following their release from experimentally infected molluscs, and refer to this novel route of parasite transmission as intermediesis. The implications of snail-to-snail transmission in the epidemiology of snail-borne diseases are also discussed

    AVALIAÇÃO DA EFICIÊNCIA DO USO DE FERTILIZANTES FOLIARES NA CULTURA DO FEIJÃO

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    Este trabalho teve como objetivo avaliar o comportamento da cultura do feijoeiro quando submetida a doses crescentes de fertilizante foliar. O trabalho foi conduzido no município de Dionísio Cerqueira/SC. Foram analisadas 6 diferentes doses do fertilizante foliar Grão Max®, sendo que os parâmetros analisados foram a massa de mil sementes, o número de grãos por vagem e o número de vagens por planta. Segundo os parâmetros seguidos de acordo com a analise estatística não houve diferença mínima significativa entre as diferentes tratamentos de acordo com os parâmetros analisados. Segundo os resultados obtidos no presente trabalho, o fertilizante foliar aplicado na fase R6 não apresentou resultados de incremento naprodutividade

    Malária transfusional: relato de caso de doador assintomático infectado por Plasmodium malariae

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    Malaria in Brazil is endemic in the Amazon region, but autochthonous cases with low parasitaemia occur in the Atlantic Forest area of the country. According to Brazilian legislation no test is mandatory for blood donors from non-endemic areas. However if they have traveled to malaria transmission regions they are deferred for six months before they can donate. This report describes a transfusion-transmitted malaria case in Sao Paulo, Brazil, where one recipient received infected blood and developed the disease. He lived in Sao Paulo and had no previous transfusion or trips to endemic areas, including those of low endemicity, such as Atlantic Forest. Thick blood smears confirmed Plasmodiummalariae. All donors lived in Sao Paulo and one of them (Donor 045-0) showed positive hemoscopy and PCR. This asymptomatic donor had traveled to Juquia, in the Atlantic Forest area of S ao Paulo State, where sporadic cases of autochthonous malaria are described. DNA assay revealed P. malariae in the donor's (Donor 045-0) blood. Serum archives of the recipient and of all blood donors were analyzed by ELISA using both P. vivax and P. falciparum antigens, and IFAT with P. malariae. Donor 045-0's serum was P. malariae IFAT positive and the P. vivax ELISA was reactive. In addition, two out of 44 donors' archive sera were also P. vivax ELISA reactive. All sera were P. falciparum ELISA negative. This case suggests the need of reviewing donor selection criteria and deferral strategies to prevent possible cases of transfusion-transmitted malaria.No Brasil a malária é endêmica na Amazônia, porém casos autóctones com baixas parasitemias ocorrem na área costeira de Mata Atlântica. De acordo com a legislação brasileira, não são obrigatórios testes para detecção de malária em doadores de sangue de áreas não-endêmicas; entretanto são excluídos por seis meses aqueles com relato de deslocamento para áreas de transmissão. Este trabalho descreve um caso de malária transfusional ocorrido em São Paulo, Brasil, em que um paciente recebeu sangue infectado, desenvolvendo a doença. Ele residia em São Paulo e não apresentava histórico de transfusão anterior ou deslocamentos para áreas endêmicas, incluindo as de baixa endemicidade, como a Mata Atlântica. A gota espessa revelou Plasmodium malariae. Os doadores eram residentes em São Paulo e um deles (045-0) apresentou hemoscopia e PCR positivos. Este era assintomático com PCR positiva para P. malariae e viagem para Juquiá, Mata Atlântica de São Paulo, onde são descritos casos esporádicos de malária autóctone. Amostras de soro do receptor e de todos os doadores foram ensaiadas por ELISA com antígenos de P. vivax e P. falciparum e RIFI com P. malariae. O doador 045-0 apresentou RIFI positiva para P. malariae. ELISA-P. vivax foi reagente no doador infectado (045-0) e em dois dos 44 doadores. Todos os soros foram negativos com antígeno de P. falciparum. Este caso aponta a necessidade de revisão dos critérios de triagem clínico-epidemiológica para evitar casos transfusionais e também adequar as estratégias de exclusão de doadores de sangue

    Release of Lungworm Larvae from Snails in the Environment: Potential for Alternative Transmission Pathways

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    Background: Gastropod-borne parasites may cause debilitating clinical conditions in animals and humans following the consumption of infected intermediate or paratenic hosts. However, the ingestion of fresh vegetables contaminated by snail mucus and/or water has also been proposed as a source of the infection for some zoonotic metastrongyloids (e.g., Angiostrongylus cantonensis). In the meantime, the feline lungworms Aelurostrongylus abstrusus and Troglostrongylus brevior are increasingly spreading among cat populations, along with their gastropod intermediate hosts. The aim of this study was to assess the potential of alternative transmission pathways for A. abstrusus and T. brevior L3 via the mucus of infected Helix aspersa snails and the water where gastropods died. In addition, the histological examination of snail specimens provided information on the larval localization and inflammatory reactions in the intermediate host. Methodology/Principal Findings: Twenty-four specimens of H. aspersa received ~500 L1 of A. abstrusus and T. brevior, and were assigned to six study groups. Snails were subjected to different mechanical and chemical stimuli throughout 20 days in order to elicit the production of mucus. At the end of the study, gastropods were submerged in tap water and the sediment was observed for lungworm larvae for three consecutive days. Finally, snails were artificially digested and recovered larvae were counted and morphologically and molecularly identified. The anatomical localization of A. abstrusus and T. brevior larvae within snail tissues was investigated by histology. L3 were detected in the snail mucus (i.e., 37 A. abstrusus and 19 T. brevior) and in the sediment of submerged specimens (172 A. abstrusus and 39 T. brevior). Following the artificial digestion of H. aspersa snails, a mean number of 127.8 A. abstrusus and 60.3 T. brevior larvae were recovered. The number of snail sections positive for A. abstrusus was higher than those for T. brevior. Conclusions: Results of this study indicate that A. abstrusus and T. brevior infective L3 are shed in the mucus of H. aspersa or in water where infected gastropods had died submerged. Both elimination pathways may represent alternative route(s) of environmental contamination and source of the infection for these nematodes under field conditions and may significantly affect the epidemiology of feline lungworms. Considering that snails may act as intermediate hosts for other metastrongyloid species, the environmental contamination by mucus-released larvae is discussed in a broader context

    Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

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    Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

    acreg: Arbitrary correlation regression

    No full text
    We present acreg, a new command that implements the arbitrary clustering correction of standard errors proposed in Colella et al. (2019, IZA discussion paper 12584). Arbitrary here refers to the way observational units are correlated with each other: we impose no restrictions so that our approach can be used with a wide range of data. The command accommodates both cross-sectional and panel databases and allows the estimation of ordinary least-squares and twostage least-squares coefficients, correcting standard errors in three environments: in a spatial setting using units’ coordinates or distance between units, in a network setting starting from the adjacency matrix, and in a multiway clustering framework taking multiple clustering variables as input. Distance and time cutoffs can be specified by the user, and linear decays in time and space are also optional

    acreg: Arbitrary correlation regression

    No full text
    We present acreg, a new command that implements the arbitrary clustering correction of standard errors proposed in Colella et al. (2019, IZA discussion paper 12584). Arbitrary here refers to the way observational units are correlated with each other: we impose no restrictions so that our approach can be used with a wide range of data. The command accommodates both cross-sectional and panel databases and allows the estimation of ordinary least-squares and twostage least-squares coefficients, correcting standard errors in three environments: in a spatial setting using units’ coordinates or distance between units, in a network setting starting from the adjacency matrix, and in a multiway clustering framework taking multiple clustering variables as input. Distance and time cutoffs can be specified by the user, and linear decays in time and space are also optional
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