687 research outputs found

    Lifelong information-driven exploration to complete and refine 4-D spatio-temporal maps

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    This paper presents an exploration method that allows mobile robots to build and maintain spatio-temporal models of changing environments. The assumption of a perpetuallychanging world adds a temporal dimension to the exploration problem, making spatio-temporal exploration a never-ending, life-long learning process. We address the problem by application of information-theoretic exploration methods to spatio-temporal models that represent the uncertainty of environment states as probabilistic functions of time. This allows to predict the potential information gain to be obtained by observing a particular area at a given time, and consequently, to decide which locations to visit and the best times to go there. To validate the approach, a mobile robot was deployed continuously over 5 consecutive business days in a busy office environment. The results indicate that the robot’s ability to spot environmental changes i

    Mapping the Hidden Diversity of the \u3cem\u3eGeophagus sensu stricto\u3c/em\u3e Species Group (Cichlidae: Geophagini) From the Amazon Basin

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    South American freshwater ichthyofauna is taxonomically the most diverse on the planet, yet its diversity is still vastly underestimated. The Amazon basin alone holds more than half of this diversity. The evidence of this underestimation comes from the backlog of morphologically distinct, yet undescribed forms deposited in museum collections, and from DNA-based inventories which consistently identify large numbers of divergent lineages within even well-studied species groups. In the present study, we investigated lineage diversity within the Geophagus sensu stricto species group. To achieve these objectives, we analyzed 337 individuals sampled from 77 locations within and outside the Amazon basin representing 10 nominal and six morphologically distinct but undescribed species. We sequenced the mitochondrial cytochrome c oxidase subunit I (COI) and delimited lineages using four different single-locus species discovery methods (mPTP-15 lineages; LocMin-14 lineages; bGMYC-18 lineages; and GMYC-30 lineages). The six morphologically distinct but undescribed species were also delimited by the majority of the species discovery methods. Five of these lineages are restricted to a single collection site or a watershed and their habitats are threatened by human activities such as deforestation, agricultural activities and construction of hydroelectric plants. Our results also highlight the importance of combining DNA and morphological data in biodiversity assessment studies especially in taxonomically diverse tropical biotas

    Divergent Effects of Metformin on an Inflammatory Model of Parkinson’s Disease

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    The oral antidiabetic drug metformin is known to exhibit anti-inflammatory properties through activation of AMP kinase, thus protecting various brain tissues as cortical neurons, for example. However, the effect of metformin on the substantia nigra (SN), the main structure affected in Parkinson’s disease (PD), has not yet been studied in depth. Inflammation is a key feature of PD and it may play a central role in the neurodegeneration that takes place in this disorder. The aim of this work was to determine the effect of metformin on the microglial activation of the SN of rats using the animal model of PD based on the injection of the pro-inflammogen lipopolysaccharide (LPS). In vivo and in vitro experiments were conducted to study the activation of microglia at both the cellular and molecular levels. Our results indicate that metformin overall inhibits microglia activation measured by OX-6 (MHCII marker), IKKÎČ (pro-inflammatory marker) and arginase (anti-inflammatory marker) immunoreactivity. In addition, qPCR experiments reveal that metformin treatment minimizes the expression levels of several pro- and anti-inflammatory cytokines. Mechanistically, the drug decreases the phosphorylated forms of mitogen-activated protein kinases (MAPKs) as well as ROS generation through the inhibition of the NADPH oxidase enzyme. However, metformin treatment fails to protect the dopaminergic neurons of SN in response to intranigral LPS. These findings suggest that metformin could have both beneficial and harmful pharmacological effects and raise the question about the potential use of metformin for the prevention and treatment of PD.España MINECO SAF2015-64171-

    Evidence of multiple paternal contribution in Podocnemis sextuberculata (Testudines: Podocnemididae) detected by microsatellite markers

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    EvidĂȘncia de contribuição paterna mĂșltipla em Podocnemis sextuberculata (Chelonia: Podocnemididae) por meio de marcadores microssatĂ©lites. Encontramos evidĂȘncias de paternidade mĂșltipla em uma amostra de 80 recĂ©m-eclodidos de sete ninhos de Podocnemis sextuberculata situados ao longo do rio Amazonas, no municĂ­pio de Barreirinha, AM, Brasil, e 54 indivĂ­duos recĂ©m-eclodidos de cinco ninhos na Reserva BiolĂłgica Abufari, TapauĂĄ, AM, Brasil. Como observado em outras espĂ©cies do gĂȘnero, P. sextuberculata apresentou comportamento poliĂąndrico. Por meio da frequĂȘncia alĂ©lica e variação em seis locos microssatĂ©lite para cada localidade, a ocorrĂȘncia de paternidade mĂșltipla em ninhos amostrados dessa espĂ©cie foi inferida, mesmo o genĂłtipo da mĂŁe sendo desconhecido. Para um dos ninhos, um mĂ­nimo de quatro machos contribuĂ­ram para a prole, enquanto que para quase todos os outros ninhos, pelo menos dois machos contribuĂ­ram. Apenas um dos 12 ninhos nĂŁo mostrou evidĂȘncia clara de contribuição de mais de um macho. Esta Ă© a primeira evidĂȘncia genĂ©tica de paternidade mĂșltipla em P. sextuberculata.Evidence of multiple paternity in Podocnemis sextuberculata (Testudines: Podocnemididae) detected by microsatellite markers. We found evidence of multiple paternity in a sample of 12 Podocnemis sextuberculata nests including seven nests (80 hatchlings) collected along the Amazonas River, in the municipality of Barreirinha, AM, Brazil and five nests in the Abufari Biological Reserve, TapauĂĄ, AM, Brazil (54 hatchlings). As observed in other species of the genus, P. sextuberculata also presented polyandric behavior. By means of allelic frequency and variation in six microsatellite loci for each location, the occurrence of multiple paternity in sampled nests of this species was inferred, even though the maternal genotype was unknown. For one of the nests, a minimum of four males contributed to the clutch, whereas for nearly all remaining nests at least two males contributed. Only one of the twelve nests did not show clear evidence for contributions from more than one male. This is the first genetic evidence of multiple paternity in P. sextuberculat

    O impacto da Lei Pelé nas negociaçÔes dos atletas do futebol brasileiro no período entre 2018 e 2019: uma anålise com enfoque na Teoria dos Jogos

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    As transaçÔes de atletas de futebol no movimenta a economia brasileira com altas cifras. A norma que permite as negociaçÔes entre clubes e os atletas, muitas vezes representados por empresårios são regulamentados pela Lei Federal n 9615/1998, (Lei Pelé) que formaliza o contrato de trabalho entre as partes, com clausulas que flexibilizam negociaçÔes futuras. O presente trabalho tem como objetivo analisar as interaçÔes das negociaçÔes de contratos, com base na Teoria dos Jogos. Para esta interação criou-se quatro anålises condicionais: Negociação simultùnea, sequencial, transação com o exterior e negociação em fim de carreira. Para o clube, serå vantajoso renovar com o atleta com potencial e posteriormente vende-lo para o exterior. O atleta com potencial de mercado irå jogar no exterior, se a oferta de salårio do clube estrangeiro for maior que do clube presente. E para o atleta em fim de carreira, o contrato dependerå do valor utilidade para o clube vinculado

    A preliminary inventory of the catfishes of the lower Rio NhamundĂĄ, Brazil (Ostariophysi, Siluriformes)

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    The Rio NhamundĂĄ is a poorly-known clearwater river draining the southern Guiana Shield of Brazil. In this study we report the findings of a preliminary ichthyological survey, focusing on catfishes (Siluriformes). We identify a total of 36 species (31 genera, seven families) from the NhamundĂĄ, including 11 species already recorded from the river. Overall, our survey results show that even rapid surveys can provide important information on Amazon fish biodiversity, suggesting potential new species, providing range extensions for nominal species, and additionally highlighting taxa in need of taxonomic revision and genetic study. As well as the traditional forms of data collected on biodiversity surveys (i.e. preserved specimen vouchers), our study also provides "new" types of data in the form of DNA barcodes and images of fishes exhibiting colouration in life, information that will be invaluable in future work addressing difficult groups. O Rio NhamundĂĄ Ă© um rio de ĂĄgua clara, pouco conhecido, que drena parte do Escudo das Guianas em territĂłrio brasileiro. Nesse estudo, nĂłs reportamos os resultados de um levantamento ictiofaunĂ­stico preliminar dessa ĂĄrea, tendo como foco os bagres (Siluriformes). NĂłs identificamos um total de 36 espĂ©cies (31 gĂȘneros, sete famĂ­lias) provenientes de nossa coleta, e adicionamos 11 espĂ©cies jĂĄ conhecidas para o rio. De maneira geral, os resultados de nossa pesquisa mostram que mesmo levantamentos rĂĄpidos podem gerar informaçÔes importantes sobre a biodiversidade de peixes amazĂŽnicos, sugerindo potenciais espĂ©cies novas, ampliando a ĂĄrea de distribuição de espĂ©cies, alĂ©m de apontar a necessidade de revisĂ”es taxonĂŽmicas e estudos genĂ©ticos para alguns taxa. Para alĂ©m das formas tradicionais de dados coletados em pesquisas de biodiversidade (i.e. espĂ©cimes preservados), nosso estudo fornece "novas" formas de dados, como DNA barcodes e imagens com o padrĂŁo de coloração dos espĂ©cimes vivos, informaçÔes essas que serĂŁo de valor inestimĂĄvel para futuros estudos que abordem grupos taxonĂŽmicos difĂ­ceis. © Collins R et al

    Divergent Effects of Metformin on an Inflammatory Model of Parkinson’s Disease

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    The oral antidiabetic drug metformin is known to exhibit anti-inflammatory properties through activation of AMP kinase, thus protecting various brain tissues as cortical neurons, for example. However, the effect of metformin on the substantia nigra (SN), the main structure affected in Parkinson’s disease (PD), has not yet been studied in depth. Inflammation is a key feature of PD and it may play a central role in the neurodegeneration that takes place in this disorder. The aim of this work was to determine the effect of metformin on the microglial activation of the SN of rats using the animal model of PD based on the injection of the pro-inflammogen lipopolysaccharide (LPS). In vivo and in vitro experiments were conducted to study the activation of microglia at both the cellular and molecular levels. Our results indicate that metformin overall inhibits microglia activation measured by OX-6 (MHCII marker), IKKÎČ (pro-inflammatory marker) and arginase (anti-inflammatory marker) immunoreactivity. In addition, qPCR experiments reveal that metformin treatment minimizes the expression levels of several pro- and anti-inflammatory cytokines. Mechanistically, the drug decreases the phosphorylated forms of mitogen-activated protein kinases (MAPKs) as well as ROS generation through the inhibition of the NADPH oxidase enzyme. However, metformin treatment fails to protect the dopaminergic neurons of SN in response to intranigral LPS. These findings suggest that metformin could have both beneficial and harmful pharmacological effects and raise the question about the potential use of metformin for the prevention and treatment of PD
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