408 research outputs found

    Large Scale Structure and Cosmic Rays revisited

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    We investigate the possibility that ultra high energy cosmic rays (E > 10^19 eV) are related to the distribution of matter on large scales. The large scale structure (LSS) data stems from the recent IRAS PSCz redshift survey. We present preliminary predictions drawn from an anisotropic distribution of sources which follows the galaxy distribution.Comment: 6 pages, 2 figures, uses World Scientific style. To appear in the proceedings of "Third International Workshop on New Worlds in Astro-Particle Physics", 1-3 Set. 2000, Faro, Portugal and X ENAA, 27-28 Jul. 2000, Lisbon, Portuga

    Topical insecticide treatments to protect dogs from sand fly vectors of leishmaniasis.

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    We compared the susceptibility of sand fly vectors to four topical insecticide treatments applied to domestic dogs, a reservoir of human leishmaniasis. Dogs were exposed to sand flies pretreatment and at 1 week, 1 month, and 2 months posttreatment. Sand fly bloodfeeding and survival rate of both fed and unfed flies were significantly reduced by the permethrin, deltamethrin, and fenthion treatments, but diazinon had no effect. The survival rate of bloodfed sand flies was reduced by up to 86% with deltamethrin collars. The antifeeding effect suggests that deltamethrin collars may be recommended to dog owners to protect their pets from sandfly- borne diseases. The combined effects on sand fly feeding and survival indicate that epidemiologic, community-based trials are warranted to test whether deltamethrin collars could reduce the incidence of canine and, hence, human leishmaniasis

    Identification of pegmatites zones in Muiane and Naipa (Mozambique) from Sentinel-2 images, using band combinations, band ratios, PCA and supervised classification

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    Remote sensing has been widely used in Geological Sciences for different applications, such as to identify geological and mineralogical objects and surface alteration changes. This study aimed to analyze the Sentinel-2 potential to detect pegmatite bodies and associated alteration zones in Muiane and Naipa in Mozambique. Different remote sensing techniques were applied to a Sentinel-2 image: RGB combinations, band ratios, principal component analysis (PCA), and supervised image classification algorithms such as the Maximum Likelihood Classifier (MLC) and Support Vector Machine (SVM). MLC was used as a benchmark classifier to evaluate the performance of SVM because MLC is the predominant algorithm employed in remote sensing classification studies. For that, several statistical metrics based on the confusion matrices were computed, namely accuracy, Kappa index, precision, recall, and f-score, among others. This study allows identifying the location of pegmatites by direct identification and segregating between hydrothermally altered zones and non-altered areas through remote sensing data/techniques, supported by field data. The field campaigns allowed for validating the results obtained and verifying the pegmatites identified using Sentinel-2 data that were not previously mapped. Moreover, reflectance spectroscopy studies in the laboratory were conducted on the samples collected in the field campaigns allow to validate the adequacy of the methodology proposed in this study. The results show that the precise identification of pegmatite targets requires a high spatial resolution such as Sentinel-2 images. Thus, with the integration of high spatial and spectral resolution data, a potential level of precision and accuracy can be achieved in the study areas

    Serological survey for Leishmania sp. infection in wild animals from the municipality of Maringá, Paraná state, Brazil

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    Leishmania sp. infection was investigated in wild animals from the Ingá Park, in the municipality of Maringá, Paraná state, Brazil, where American cutaneous leishmaniasis (ACL) is an endemic disease. Sixty-five mammals, comprising Didelphis albiventris, Cerdocyon thous, Lycalopex vetulus, Cebus apella, Dasyprocta azarae, Dasypus novemcinctus, Procyon cancrivorus and Nasua nasua, were captured. Blood samples were collected for parasite cultivation. Antibodies were investigated by direct agglutination test (DAT) using Leishmania (Viannia) braziliensis as antigen. Flagellates were observed in blood cultures of 14 (35.9%) Didelphis albiventris. Anti-Leishmania antibodies were detected in 31 (51.6%) specimens of Cerdocyon thous, Lycalopex vetulus, Cebus apella, Dasyprocta azarae, Procyon cancrivorus and Nasua nasua. These results suggest that Cerdocyon thous and Lycalopex vetulus (crab-eating fox), Cebus apella (capuchin monkey), Dasyprocta azarae (agouti), Procyon cancrivorus (crab-eating raccoon) and Nasua nasua (coati) play an important role in the ACL transmission cycle in the northwestern region of Paraná, Brazil

    Anti rickettsia-antibody for spotted fever group in horses and dogs in the North of Paraná Stated, Brazil

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    The Brazilian Spotted Fever (BSF) is a zoonosis that can be fatal if not trteated. As there are few studies of the BSF in the Paraná State, the occurrence of BSF was serologically investigated in dogs and horses by indirect immunofluorescence assay (IFA), in the North of that State, in animals that are regarded as sentinels for BSF. A total of 241 samples of sera of equine, four of asinine, and 29 of dogs were collected in nine farms of three municipalities in the North of Paraná: Arapongas, Douradina, and Umuarama. From fifteen samples of equine serum with positive titres for RIFI, eight (53.3 %) had titre of 64 against R. rickettsii, two (13.3 %) 128 against R. rickettsii, and five (33.3 %) were reactants for R. parkeri and R. rickettsii, with titres ranging from 64 to 2048, and 128 to 1024, respectively. The results showed that domestic animals, sentinels for BSF, are under low exposition to ticks infected with spotted fever group Rickettsia, indicating low risk of human infection by these agents in the studied area
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