226 research outputs found

    Wild felid species richness affected by a corridor in the Lacandona forest, Mexico

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    Los efectos de la presencia de un corredor en la selva Lacandona, en México, en la riqueza de especies de félidos silvestres Los félidos silvestres se encuentran entre las especies más vulnerables ante la pérdida de hábitat causada por la fragmentación de los ecosistemas. Se analizó el efecto de la presencia de un corredor estructural, definido como una franja de vegetación que conecta dos fragmentos de hábitat, en la riqueza y ocupación de félidos en tres sitios de Marqués de Comillas, en Chiapas: uno comprende dos fragmentos de bosque aislados, otro presenta un corredor estructural y el último se encuentra dentro de la reserva de la biosfera Montes Azules. Se encontraron cuatro especies en el interior de la Reserva, cinco en el corredor estructural y únicamente dos (L. pardalis y H. yagouaroundi) en los fragmentos de bosque aislados. La presencia del corredor no afectó de forma significativa a la ocupación, pero debido a la baja tasa de detección, se necesita seguir investigando para descartar diferencias. Nuestros resultados resaltan la necesidad de manejar la conectividad del hábitat en los bosques remanentes para lograr la conservación de la comunidad de félidos en Marqués de Comillas, en Chiapas, México.Los efectos de la presencia de un corredor en la selva Lacandona, en México, en la riqueza de especies de félidos silvestres Los félidos silvestres se encuentran entre las especies más vulnerables ante la pérdida de hábitat causada por la fragmentación de los ecosistemas. Se analizó el efecto de la presencia de un corredor estructural, definido como una franja de vegetación que conecta dos fragmentos de hábitat, en la riqueza y ocupación de félidos en tres sitios de Marqués de Comillas, en Chiapas: uno comprende dos fragmentos de bosque aislados, otro presenta un corredor estructural y el último se encuentra dentro de la reserva de la biosfera Montes Azules. Se encontraron cuatro especies en el interior de la Reserva, cinco en el corredor estructural y únicamente dos (L. pardalis y H. yagouaroundi) en los fragmentos de bosque aislados. La presencia del corredor no afectó de forma significativa a la ocupación, pero debido a la baja tasa de detección, se necesita seguir investigando para descartar diferencias. Nuestros resultados resaltan la necesidad de manejar la conectividad del hábitat en los bosques remanentes para lograr la conservación de la comunidad de félidos en Marqués de Comillas, en Chiapas, México.Wild felids are one of the most vulnerable species due to habitat loss caused by fragmentation of ecosystems. We analyzed the effect of a structural corridor, defined as a strip of vegetation connecting two habitat patches, on the richness and habitat occupancy of felids on three sites in Marqués de Comillas, Chiapas, one with two isolated forest patches, the second with a structural corridor, and the third inside the Montes Azules Biosphere Reserve. We found only two species (L. pardalis and H. yagouaroundi) in the isolated forest patches, five species in the structural corridor, and four species inside the Reserve. The corridor did not significantly affect occupancy, but due to the low detection rates, further investigation is needed to rule out differences. Our results highlight the need to manage habitat connectivity in the remaining forests in order to preserve the felid community of Marqués de Comillas, Chiapas, México

    The statistical analysis of acoustic phonetic data: exploring differences between spoken Romance languages

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    The historical and geographical spread from older to more modern languages has long been studied by examining textual changes and in terms of changes in phonetic transcriptions. However, it is more difficult to analyze language change from an acoustic point of view, although this is usually the dominant mode of transmission. We propose a novel analysis approach for acoustic phonetic data, where the aim will be to statistically model the acoustic properties of spoken words. We explore phonetic variation and change using a time-frequency representation, namely the log-spectrograms of speech recordings. We identify time and frequency covariance functions as a feature of the language; in contrast, mean spectrograms depend mostly on the particular word that has been uttered. We build models for the mean and covariances (taking into account the restrictions placed on the statistical analysis of such objects) and use these to define a phonetic transformation that models how an individual speaker would sound in a different language, allowing the exploration of phonetic differences between languages. Finally, we map back these transformations to the domain of sound recordings, allowing us to listen to the output of the statistical analysis. The proposed approach is demonstrated using recordings of the words corresponding to the numbers from ``one'' to ``ten'' as pronounced by speakers from five different Romance languages.John Coleman appreciates the support of UK Arts and Humanities Research Council grant AH/M002993/1, “Ancient Sounds: mixing acoustic phonetics, statistics and comparative philology to bring speech back from the past”. John Aston appreciates the support of UK Engineering and Physical Sciences Research Council grant EP/K021672/2, “Functional Object Data Analysis and its Applications”

    A feed-forward pathway drives LRRK2 kinase membrane recruitment and activation

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    Activating mutations in the leucine-rich repeat kinase 2 (LRRK2) cause Parkinson’s disease, and previously we showed that activated LRRK2 phosphorylates a subset of Rab GTPases (Steger et al., 2017). Moreover, Golgi-associated Rab29 can recruit LRRK2 to the surface of the Golgi and activate it there for both auto- and Rab substrate phosphorylation. Here, we define the precise Rab29 binding region of the LRRK2 Armadillo domain between residues 360–450 and show that this domain, termed ‘site #1,’ can also bind additional LRRK2 substrates, Rab8A and Rab10. Moreover, we identify a distinct, N-terminal, higher-affinity interaction interface between LRRK2 phosphorylated Rab8 and Rab10 termed ‘site #2’ that can retain LRRK2 on membranes in cells to catalyze multiple, subsequent phosphorylation events. Kinase inhibitor washout experiments demonstrate that rapid recovery of kinase activity in cells depends on the ability of LRRK2 to associate with phosphorylated Rab proteins, and phosphorylated Rab8A stimulates LRRK2 phosphorylation of Rab10 in vitro. Reconstitution of purified LRRK2 recruitment onto planar lipid bilayers decorated with Rab10 protein demonstrates cooperative association of only active LRRK2 with phospho-Rab10-containing membrane surfaces. These experiments reveal a feed-forward pathway that provides spatial control and membrane activation of LRRK2 kinase activity

    Sistema de controle de temperatura para câmara de armazenamento de alimentos frescos em meio líquido.

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    Neste trabalho é proposto um sistema de controle da temperatura para uma câmara na qual os produtos (já embalados) são armazenados imersos em meio Irquido. Esta metodologia de armazenamento permite aumentar o tempo de prateleira de produtos vegetais frescos através da redução da temperatura, sem o perigo de congelar os produtos armazenados. Foi avaliado o desempenho do sistema de controle quanto à precisão e gradientes internos em comparação com uma câmara convencional de meio aéreo. Os resultados mostraram que a nova metodologia permite armazenar produtos frescos com segurança à apenas Q,4°C acima do ponto de congelamento, enquanto que em câmaras convencionais esses devem ser armazenados à, pelo menos, 2,QoC acima do ponto de congelamento.bitstream/CNPDIA/8730/1/BPD04_2003.pd

    “Silica and zirconia supported catalysts for the low-temperature ethanol steam reforming"

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    Ethanol steam reforming has been investigated in the low temperature range, focusing not only on H2pro-ductivity, but also on catalyst stability, very critical parameters under such conditions. Different supports(SiO2and ZrO2), active phases (Ni, Co, Cu) and reaction temperature (300–500◦C) have been employed.Ni confirmed the best performing active phase to promote ethanol decomposition and reforming alreadyat low reaction temperature. However, stability towards coking remains a key problem. The supportplays a key role from this point of view. Indeed, the stabilization of the active phase in very dispersedform allowed to reach stable catalyst performance with time-on-stream. SiO2, thanks to no Lewis acidityand sufficiently strong metal–support interaction, demonstrated an interesting support for Ni under theselected operating condition

    Sphyrna tudes, Smalleye Hammerhead

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    The Smalleye Hammerhead (Sphyrna tudes) is a medium-sized (to 150 cm total length) shark that occurs in the Western Central and Southwest Atlantic from Colombia to the Rio de La Plata, Argentina. It inhabits inshore waters over the continental shelf at depths of 5–80 m. It is captured in intense and largely unmanaged commercial and artisanal beach seines, gillnets, longlines, and trawls throughout its geographic range. This shark is targeted or retained as bycatch for its meat, which is consumed or sold locally. There are few data on population reduction but these intensive unmanaged fisheries are suspected to have caused reductions and possibly local extinctions throughout this species' range. For example, in Brazil, this hammerhead has not been recorded in 35 years from Ceará state and it is considered by local fishers to be depleted in Bahia state. This shark is supposed to be strictly protected in Brazil, but it is clear that it is still landed and traded in various states. Overall, due to intense and largely unmanaged fisheries across its range, lack of refuge at depth, suspected declines in many areas and local extinctions suspected from an absence of records (despite continued sampling and observation), and its relatively unproductive life history, it is suspected that the Smalleye Hammerhead has undergone a population reduction of >80% over the past three generations (37 years), and it is assessed as Critically Endangered A2bd.Fil: Pollom, R.. University Fraser Simon; CanadáFil: Barreto, R.. Instituto Chico Mendes de Conservacao Da Biodiversidade; BrasilFil: Charvet, P.. Universidade Federal do Paraná; BrasilFil: Chiaramonte, Gustavo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia". Estación Hidrobiológica de Puerto Quequén (sede Quequén); ArgentinaFil: Cuevas, J. M.. Wildlife Conservation Society; Estados UnidosFil: Faria, V.. Universidade Federal Do Ceara; BrasilFil: Herman, K.. Georgia Aquarium; Estados UnidosFil: Lasso Alcala, O.. Fundación la Salle de Ciencias Naturales; VenezuelaFil: Marcante, F.. Universidade Federal Do Rio Grande.; BrasilFil: Mejía Falla, P.A.. Wildlife Conservation Society; Estados UnidosFil: Montealegre Quijano, S.. Universidade Federal de Sao Paulo; BrasilFil: Motta, F.. Universidade Federal de Sao Paulo; BrasilFil: Navia, A. F.. Fundación Squalus; ColombiaFil: Nunes, J.. Universidade Federal Do Maranhao.; BrasilFil: Paesch, L.. Dirección Nacional de Recursos Acuáticos; UruguayFil: Rincon, G.. Universidade Federal Do Maranhao.; Brasi

    Algoritmos evolutivos híbridos para el diseño y operación eficiente de una red de distribución de agua potable

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    Los Algoritmos Evolutivos (AEs) han sido ampliamente utilizados de forma exitosa en las últimas dos décadas para resolver diferentes problemas de redes distribución de agua. El problema de diseño de una red de distribución de agua (RDA) ha sido reconocido como un problema NPduro que no puede ser resuelto fácilmente usando técnicas matemáticas tradicionales. En esta línea de trabajo se utilizan dos algoritmos Evolutivos (Algoritmo Genético Celular – cGA- y Algoritmo CHC - Crossover elitism population, Half uniform crossover combination, Cataclysm mutation) no tan utilizados en la literatura para resolver este problema pero que han tenido resultados exitosos en distintos problemas de optimización. Además, se pretende incorporar versiones híbridas de ambos algoritmos actualmente utilizadas en diversos problemas de optimización en el marco otros proyectos de investigación llevados a cabo en el Laboratorio de Tecnologías Emergentes. Con estos algoritmos se intenta brindar soluciones al diseño de una red eficiente de distribución de agua potable para la localidad de Caleta Olivia.Eje: Agentes y Sistemas InteligentesRed de Universidades con Carreras en Informática (RedUNCI

    Distribuição e pontos de concentração de áreas de predação de tartarugas marinhas por onças pintadas em parque nacional da Costa Rica

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    A poorly described aspect of the trophic relation between sea turtles and jaguars is the distribution and hotspots of the feeding areas of jaguars on the nesting beaches. It is very important to identify the areas where sea turtles are predated because we could concentrate conservation and management efforts in these areas. Therefore, the aim of this work is to describe the spatial distribution and hotspots of the feeding areas of jaguars at Nancite beach, Santa Rosa National Park, Costa Rica. We recorded a total of 76 predated carapaces of sea turtles, of these, 54 (71%) were of Lepidochelys olivacea and 22 (29%) of Chelonia mydas. Two major feeding hotspots areas were identified within the Nancite beach. Both hotspots are located at the extremes of the beach, one is at the southern edge and the other is at the northern extreme. Human activity and the distribution of nesting turtles influence synergistically to determine the sites where the sea turtles are predated at Nancite beach. Based on the information of predation hotspots, the environmental authorities should regulate the monitoring activities within those areas to avoid interfering with the trophic relation between sea turtles and jaguars.Keywords: hunting area, jaguar predation, nesting beach, predatory behavior, human-wildlife interactions.Um aspecto pouco descrito da relação trófica entre tartarugas marinhas e onças pintadas é a distribuição e os pontos de acesso das áreas de alimentação de onças nas praias de nidificação. Identificar a área onde tartarugas marinhas são predadas é muito importante, porque podemos concentrar os esforços de conservação e de gestão nessas áreas. Portanto, o objetivo deste trabalho é identificar a distribuição espacial e os hotspots das áreas de alimentação de onças pintadas na praia Nancite, Parque Nacional de Santa Rosa, Costa Rica. Registramos um total de 76 carapaças predadas de tartarugas marinhas, das quais 54 (71%) eram de Lepidochelys olivacea e 22 (29%) de Chelonia mydas. Duas grandes áreas de hotspots de alimentação foram identificadas na praia Nancite. Ambos os hotspots estão localizados nos extremos da praia, sendo um no extremo sul e o outro no extremo norte. A atividade humana e a distribuição de nidificação de tartarugas influenciam sinergicamente para determinar os locais onde as tartarugas marinhas são predadas na praia Nancite. Com base nas informações de hotspots de predação, as autoridades ambientais devem regular as atividades de monitoramento nessas áreas, para evitar interferências na relação trófica entre tartarugas marinhas e onças.Palavras-chave: área de caça, predação de onças, praia de nidificação, comportamento predatório, interações entre humanos e vida selvagem
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