243 research outputs found

    Swimming abilities of temperate pelagic fish larvae prove that they may control their dispersion in coastal areas

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    The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sensorial acuity of temperate fish larvae allows them to find and swim towards coastal nursery areas, which are crucial for their recruitment. To gather further evidence to support this theory, it is necessary to understand how horizontal swimming capability varies along fish larvae ontogeny. Therefore, we studied the swimming capability of white seabream Diplodus sargus (Linnaeus, 1758) larvae along ontogeny, and their relationship with physiological condition. Thus, critical swimming speed (U-crit) and the distance swam (km) during endurance tests were determined for fish larvae from 15 to 55 days post-hatching (DPH), and their physiological condition (RNA, DNA and protein contents) was assessed. The critical swimming speed of white seabream larvae increased along ontogeny from 1.1 cm s(-1) (15 DPH) to 23 cm s(-1) (50 and 55 DPH), and the distance swam by larvae in the endurance experiments increased from 0.01 km (15 DPH) to 86.5 km (45 DPH). This finding supports one of the premises of the SAAB hypothesis, which proposes that fish larvae can influence their transport and distribution in coastal areas due to their swimming capabilities. The relationship between larvae's physiological condition and swimming capabilities were not evident in this study. Overall, this study provides critical information for understanding the link between population dynamics and connectivity with the management and conservation of fish stocks.Funding Agency Portuguese Foundation for Science and Technology SFRH/BD/104209/2014 Portuguese Foundation for Science and Technology UID/Multi/04326/2019 FCT, under the Transitional Norm DL57/2016/CP[1361]/CT[CT0008 CLIMFISH project-A framework for assess vulnerability of coastal fisheries to climate change in Portuguese coast n2/SAICT/2017-SAICTinfo:eu-repo/semantics/publishedVersio

    A sala de aula contemporânea – desafios

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    O texto parte da consideração sobre o caráter macroestrutural da problemáticaeducacional e chega à sala de aula. A partir daí analisa os atuais desafios, contemplandoduas questões: os momentos do aprender (as várias propostas para a sala de aula, as diretrizese bases ligadas aos conteúdos, às habilidades e às competências, a formação de professores)e as perspectivas para o ensino do futuro. Conclui apontando pistas para avançar em busca deuma educação democrática em todos os níveis de escolaridade

    Analysis of Visible/SWIR surface reflectance ratios for aerosol retrievals from satellite in Mexico City urban area

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    International audienceThe surface reflectance ratio between the visible (VIS) and shortwave infrared (SWIR) radiation is an important quantity for the retrieval of the aerosol optical depth (?a) from the MODIS sensor data. Based on empirically determined VIS/SWIR ratios, MODIS ?a retrieval uses the surface reflectance in the SWIR band (2.1 µm), where the interaction between solar radiation and the aerosol layer is small, to predict the visible reflectances in the blue (0.47 µm) and red (0.66 µm) bands. Therefore, accurate knowledge of the VIS/SWIR ratio is essential for achieving accurate retrieval of aerosol optical depth from MODIS. We analyzed the surface reflectance over some distinct surface covers in and around the Mexico City metropolitan area (MCMA) using MODIS radiances at 0.66 µm and 2.1 µm. The analysis was performed at 1.5 km×1.5 km spatial resolution. Also, ground-based AERONET sun-photometer data acquired in Mexico City from 2002 to 2005 were analyzed for aerosol depth and other aerosol optical properties. In addition, a network of hand-held sun-photometers deployed in Mexico City, as part of the MCMA-2006 Study during the MILAGRO Campaign, provided an unprecedented measurement of ?a in 5 different sites well distributed in the city. We found that the average RED/SWIR ratio representative of the urbanized sites analyzed is 0.73±0.06 for scattering angles a averaged from sun-photometer measurements. The use of the new RED/SWIR ratio of 0.73 in the MODIS retrieval over Mexico City led to a significant improvement in the agreement between the MODIS and sun-photometer AOD results; with the slope, offset, and the correlation coefficient of the linear regression changing from (?aMODIS=0.91?a sun-photometer+0.33, R2=0.66) to (?aMODIS=0.96 ?a sun-photometer?0.006, R2=0.87). Indeed, an underestimation of this ratio in urban areas lead to a significant overestimation of the AOD retrieved from satellite. Therefore, we strongly encourage similar analyses in other urban areas to enhance the development of a parameterization of the surface ratios accounting for urban heterogeneities

    Urban Visible/SWIR surface reflectance ratios from satellite and sun photometer measurements in Mexico City

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    International audienceThe surface reflectance ratio between the visible (VIS) and shortwave infrared (SWIR) radiation is an important quantity for the retrieval of the aerosol optical depth (?a) from the MODIS sensor data. Based on empirically determined VIS/SWIR ratios, MODIS ?a retrieval uses the surface reflectance in the SWIR band (2.1 ?m), where the interaction between solar radiation and the aerosol layer is small, to predict the visible reflectances in the blue (0.47 ?m) and red (0.66 ?m) bands. Therefore, accurate knowledge of the VIS/SWIR ratio is essential for achieving accurate retrieval of aerosol optical depth from MODIS. The heterogeneity of the surface cover in an urban environment increases the uncertainties in the estimation of the surface reflectance and, consequently, ?a. We analyzed the surface reflectance over some distinct surface covers in and around the Mexico City metropolitan area (MCMA) using MODIS radiances at 0.66 ?m and 2.1 ?m. The analysis was performed at 1.5 km×1.5 km spatial resolution. Also, ground-based AERONET sun-photometer data acquired in Mexico City from 2002 to 2005 were analyzed for aerosol optical thickness and other aerosol optical properties. In addition, a network of hand-held sun-photometers deployed in Mexico City, as part of the MCMA-2006 Study during the MILAGRO Campaign, provided an unprecedented measurement of ?a in 5 different sites well distributed in the city. We found that the average RED/SWIR ratio representative of the urbanized sites analyzed is 0.73±0.06. This average ratio was significantly different for non-urban sites, which was approximately 0.55. The aerosol optical thickness retrieved from MODIS radiances at a spatial resolution of 1.5 km×1.5 km and averaged within 10 x 10 km boxes were compared with collocated 1-h ?a averaged from sun-photometer measurements. The use of the new RED/SWIR ratio of 0.73 in the MODIS retrieval led to a significant improvement in the agreement between the MODIS and sun-photometer results; with the slope, offset, and the correlation coefficient of the linear regression changing from (?aMODIS = 0.91 ?a sun-photometer + 0.33 ,R2=0.66) to (?aMODIS = 0.96 ?a sun-photometer ?0.006, R2=0.87)

    Aspectos ecológicos da tripanossomose americana: I - observações sôbre o Panstrongylus megistus e suas relações com focos naturais da infecção, em área urbana da cidade de São Paulo, Brasil

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    São relatadas as investigações que levaram a efeito o encontro de foco natural da Tripanossomose Americana, na área ocupada pelo bairro denominado Chácara Flora, na cidade de São Paulo. Esse foco conta com o concurso do triatomíneo Panstrongylus megistus, de gambás Didelphis marsupialis e de ratos domésticos da espécie Rattus norvegicus. A presença destes últimos permite admitir maior aproximação da infecção no sentido do ambiente humano. O encontro de um espécimen adulto fêmea de P. megistus sugando ativamente o homem dentro da habitação, aliado à revisão da literatura, permite supor que não se trata de subespécie ecológica. A presença de diferenças essenciais de comportamento no norte e sul do Brasil, no estado atual dos conhecimentos, seria resultante, preponderantemente, da ação de fatôres ambientais, entre os quais, as condições climáticas.A natural focus of American Trypanosomiasis was found in the city of S. Paulo. It was localized in a forest area preserved for residential purposes. In this focus the participation of triatomids bugs Panstrongylus megistus, marsupials of Diaelphis marsupialis species and domestics rats Rattus norvegicus was observed. Natural infection of all of them was observed. The ecotopes were found mainly in the pinus trees Cryptomeria japonica. Beside this, an adult female of P. megistus was found suckling actively humans inside the house. Some considerations are made in this paper concerning the distribution area of that species of triatomid. The sylvatic population found currently in South Brazil, represents probably the action of environmental factors limiting the bugs to its natural ecotopes. Nevertheless, these findings suggest that, from the epidemiological point of view, some approximation of the infection to the human environment was performed, at least, in urban areas

    Um olhar humanístico sobre a educação superior brasileira

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    O texto discute as relações entre o trabalho e a educação no ensinosuperior brasileiro. Analisa as mudanças no perfil sócio-cultural dos trabalhadoresde hoje e dos estudantes que ingressam no curso superior noturno procurandomostrar suas reais condições frente às conseqüências da globalização, suasdificuldades e seus caminhos na trajetória entre trabalho e estudo. Mostra que ascausas podem ser encontradas no predomínio da formação técnica em detrimentode uma formação humanística de caráter global. Através de pesquisa bibliográficaestudam-se as contradições existentes na sociedade vendo que a educação precisaser um direito e não uma mercadoria. Aponta ainda a necessidade de um trabalhodidático-pedagógico voltado não só para a dimensão técnica, mas igualmente paraas relações sociais com ênfase no professor universitário com consciência políticae crítica. Conclui sobre a necessidade de compreender as transformações sociais,procurando na educação uma forma de construção do saber universitário comespaço para a articulação da qualidade com a quantidade, evitando a indesejáveldicotomia entre ambos os aspectos

    Correlação do Four Square Step Test e L-Test com o 6-Minute Walk Test em amputados de membro inferior

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    Reabilitação pós-amputação + Recuperação da capacidade funcional + 6-Minute Walk Test (6MWT). Objetivos do estudo: Perceber se um determinado amputado de membro inferior ao realizar com melhor desempenho, o FSST ou o L-Test, realizará também com melhor desempenho o 6MWT, sendo uma das possíveis utilidades a de se poder fazer comparações entre, por exemplo, dispositivos protésicos (pés, joelhos, etc), aquando a impossibilidade de realização do 6MWT. Considerações finais: Compatibilidade dos testes FSST e L-Test com o 6MWT. A relação entre os testes estudados torna-se um achado muito relevante, pois pode servir como base de novas medidas padrão na avaliação clínica funcional do indivíduo amputado do membro inferior.info:eu-repo/semantics/publishedVersio

    Microneedle Enhanced Delivery of Cosmeceutically Relevant Peptides in Human Skin

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    Peptides and proteins play an important role in skin health and well-being. They are also found to contribute to skin aging and melanogenesis. Microneedles have been shown to substantially enhance skin penetration and may offer an effective means of peptide delivery enhancement. The aim of this investigation was to assess the influence of microneedles on the skin penetration of peptides using fluorescence imaging to determine skin distribution. In particular the effect of peptide chain length (3, 4, 5 amino acid chain length) on passive and MN facilitated skin penetration was investigated. Confocal laser scanning microscopy was used to image fluorescence intensity and the area of penetration of fluorescently tagged peptides. Penetration studies were conducted on excised full thickness human skin in Franz type diffusion cells for 1 and 24 hours. A 2 to 22 fold signal improvement in microneedle enhanced delivery of melanostatin, rigin and pal-KTTKS was observed. To our knowledge this is the first description of microneedle enhanced skin permeation studies on these peptides
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