2,037 research outputs found

    The polygon moray, Gymnothorax polygonius (Poey, 1875) : A new record from Ascension Island, South Atlantic

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    Ascension Island (07°57′S, 14°22′W) is an isolat-ed volcanic edifice in the South Atlantic. The closest land, St. Helena is approximately 700 miles south with the closest land mass of any size being West Africa, 1000 miles to the east. Approximately 1500 miles west of Ascension Island is the coast of Brazil. As such, the fish community of the island is a mixture of eastern and western Atlantic species, although richness is relatively low compared with other similar loca-tions such as Cape Verde (Wirtz et al. 2014). Despite the apparent remoteness of Ascension Island there have been several key publications on the ichthyofauna for the island and surround-ing marine zone. The fish community of Ascen-sion was first summarized by Cadenat & Marchal (1963), with a comprehensive checklist of shal-low-water fish species published by Lubbock (1980) record-ing 71 species. A report on the benthic and near-benthic fish community, from seamounts around Ascension, was compiled in Trunov (2006). The most recent review of the ichthyofauna of Ascen-sion can be found in Wirtz et al. (2014), a study listing 173 fish species, including 12 members of the family Muraenidae. The extensive rocky ma-rine habitat of Ascension Island is often consid-ered a key factor behind the considerable abun-dance of moray eels around the island. On 21 Feburary 2015 an unidentified moray eel was caught by a recreational angler who had been fishing in deep water from a vessel off the west-ern coast of Ascension Island (Fig. 1). The spec-imen did not match any previous identification records of Muraenidae from Ascension Island. […]

    Quantum reinforcement learning: a heuristic approach to solve deterministic MDPs

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    Dissertação de mestrado integrado em Physics EngineeringThis thesis works on Reinforcement Learning tree search and attempts to find the best possible sequence of actions the agent needs to execute to get the most reward while using less computational effort than by just applying a quantum maximum finding algorithm. To achieve this we will use the property that makes it possible to limit our search space to the elements that were marked by the oracle in Grover’s Algorithm, by marking a fourth of the search space and following it with a quantum maximum finding subroutine. From this, one of the marked elements is obtained and the information encoded in it is used to update a probabilistic distribution stored in a classical memory. The goal is to encounter the minimum amount of iterations of this process and compare the results, i.e., percentage of success which is measured as the number of times the algorithm produces a solution (element with maximum reward) and the number of queries used - with a traditional quantum maximum finding procedure. If this is observed, it is also hypothe sized that the algorithm could be used to observe a step further into the future compared to the traditional procedure, i.e., use the same or fewer queries to evaluate a larger number of sequences fruit of increasing the horizon of the episodes. The last hypothesis tests the depth of the circuits, more specifically the number of gates used. If the algorithm evaluates shallower circuits than the quantum maximum finding, the approach can be applied on the current quantum machines (NISQ) because the shallower circuits produces more error-proof measurements. The results show that the proposed algorithm has no advantages compared to a traditional quantum maximum finding procedure due to using more queries to achieve the same rate of success which, consequently, invalidates the first and second hypothesis. For the third hypothesis, the gate complexity was not directly measured. Instead, was opted to measure the number of queries used by circuit which might not be sufficient to conclude that the algorithm uses shallower circuits.Esta tese trabalha com a busca em árvores utilizando a Aprendizagem por Reforço para encontrar a melhor sequência possível de ações que o agente terá de executar de forma a obter o maior prémio possível, isto enquanto usa menos esforço computacional em comparação com utilizar apenas um algoritmo de procura quântica pelo máximo. Para atingir estes objectivos, usaremos a propriedade que possibilita limitar o espaço de procura para os elementos marcados pelo oráclo no Algoritmo de Grover, marcando exatamente um quarto do espaço de procura, procedendo com uma procura quântica. Disto resulta um dos elementos marcado e a informação codificada nele será usada para atualizar uma distribuição probabilística guardada em memoria clássica. O objectivo é encontrar o mínimo de iterações deste processo necessário para obter uma percentagem de sucesso - número de vezes que o algoritmo retornou um elemento que é solução do problema e o número de queries usado - e comparar estes resultados com um procedimento tradicional de procura quântica. Caso isto se observe, é colocada a hipótese de se usar este algoritmo como forma de observar ações futuras em comparação com os algoritmos tradicionais, isto é, usar o mesmo ou menos queries para avaliar um maior número de sequências fruto do aumento do horizonte dos episódios a avaliar. A última hipótese testa se a profundidade dos circuitos, mais concretamente o número de gates usadas. Caso o algoritmo proposto utilize circuitos menos profundos que o algoritmo quantum maximum finding, este poderá ser utilizado nas máquinas quânticas atuais pois estes circuitos produzem medições mais resistentes a erros. Os resultados mostraram que o algoritmo proposto não possui qualquer vantagem comparado ao quantum maximum finding por usar mais queries para atingir a mesma percentagem de sucesso o que, consequentemente, invalida a primeira e segunda hipótese. Quanto à terceira hipótese, o número de gates usadas por circuito não foi medido diretamente. Em vez disso, optou-se por medir o número de queris por circuito o que poderá não ser suficiente para obter conclusões quanto à profundidade dos circuitos medidos

    Chemical Physics of Controlled Wettability and Super Surfaces

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    Wetting phenomena are widespread in both natural and technological contexts. Despite the well-established nature of this scientific field and our extensive knowledge of its underlying principles, wetting remains a dynamic and vibrant area of study. It continues to pose fundamental questions while offering innovative avenues for controlling these phenomena to develop novel applications. By tailoring the wetting properties of surfaces, researchers and engineers can design materials with specific functionalities, such as self-cleaning surfaces, anti-fog coatings, and enhanced slipperiness. Recent years have witnessed significant advancements in wetting research, owing to the exquisite control achieved in surface topography and chemistry and to the development of novel experimental techniques. Additionally, simulations and theory have played a crucial role in these advancements. They provid the fundamental knowledge and quantitative tools to control wettability and design surfaces with enhanced properties. Given these recent breakthroughs, this special collection Chemical Physics of Controlled Wettability and Super Surfaces becomes particularly timely and significant. It serves as a platform to showcase some of the latest developments in the field of wetting. It highlights the exciting progress and potential applications in controlling wetting properties that are enabled by the synergy between theory, simulations, and experiments.Comment: EDITORIAL: Special Topic: Chemical Physics of Controlled Wettability and Super Surface

    Metodologías para diseño de circuitos ladder con base en sistemas secuenciales y combinacionales

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    Los automatismos a través del tiempo han alcanzado un tamaño y una complejidad considerables debido a la industrialización del mundo moderno que busca realizar rutinas de producción con mayor eficiencia y en condiciones óptimas de seguridad tanto para las personas como para las máquinas, lo que ha llevado a buscar herramientas para el diseño de circuitos automáticos que logren satisfacer dichas necesidades. Con el pasar de los años se han logrado implementar circuitos automáticos que realizan funciones básicas con la interconexión de pulsadores, interruptores, contactos, temporizadores, bobinas; y lo que se busca es que estos sirvan como punto de partida para el diseño final de los automatismos requeridos, lo que los ha convertido en un estándar. Cabe anotar que el ser un estándar no significa que se puedan utilizar en todo tipo de aplicaciones, por lo que se hace necesario acondicionar los circuitos dependiendo de la aplicación que se quiera, de ahí la dificultad de los diseñadores para encontrar el circuito que cumpla con los requerimientos exigidos. En la actualidad las metodologías de diseño se han visto representadas en la prueba de circuitos sim ples a los cuales se le adicionan ciertas características que van siendo probadas para encontrar fallas e ir corrigiéndolas hasta encontrar el funcionamiento deseado, pero no se cuenta con una metodología que guíe al diseñador paso a paso, es decir, si se busca un circuito que permita implementar una ac ción, el encargado de su implementación se enfrenta a un problema que sólo podrá superar por medio de su habilidad y experiencia en el campo

    Processing Annotated TMX Parallel Corpora

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    In the later years the amount of freely available multilingual corpora has grown in an exponential way. Unfortunately the way these corpora are made available is very diverse, ranging from simple text files or specific XML schemas to supposedly standard formats like the XML Corpus Encoding Initiative, the Text Encoding Initiative, or even the Translation Memory Exchange formats. In this document we defend the usage of Translation Memory Exchange documents, but we enrich its structure in order to support the annotation of the documents with different information like lemmas, multi-words or entities. To support the adoption of the proposed formats, we present a set of tools to manipulate the different formats in an agile way

    The voice that educate rescue identities: playful interventions with a board game in the teacher's vocal health care: A voz que educa resgata identidades: intervenções lúdicas através do jogo de trilha na saúde vocal do professor

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    A teacher is susceptible to vocal disorders. Aims: To develop an activity based on an informative playful approach to teachers’ vocal health. Method: Literature review study and development of a health communication strategy from a playful approach. Results: A board game was developed, namely Teachers’ vocal health quest, containing information about vocal health. Discussion: There are many factors that compromise the health of a teacher's vocals, ranging from unhealthy habits to work organizational factors. Conclusion: The ludic can be used as a tool to take care of teachers’ vocal health

    Can one predict a drop contact angle?

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    The study of wetting phenomena is of great interest due to the multifaceted technological applications of hydrophobic and hydrophilic surfaces. The theoretical approaches proposed by Wenzel and later by Cassie and Baxter to describe the behavior of a droplet of water on a rough solid are extensively used and continuously updated to characterize the apparent contact angle of a droplet. However, the equilibrium hypothesis implied in these models means that they are not always predictive of experimental contact angles due to the strong metastabilities typically occurring in the wetting of heterogeneous surfaces. A predictive scheme for contact angles is thus urgently needed both to characterize a surface by contact angle measurements and to design super-hydrophobic and -oleophobic surfaces with the desired properties, for example, contact angle hysteresis. In this work, a combination of Monte Carlo simulation and the string method is employed to calculate the free energy profile of a liquid droplet deposited on a pillared surface. For the analyzed surfaces, it is shown that there is only one minimum of the free energy that corresponds to the superhydrophobic wetting state while the wet state can present multiple minima. Furthermore, when the surface roughness decreases the amount of local minima observed in the free energy profile increases. The presented approach clarifies the origin of contact angle hysteresis providing quantitative tools for understanding and controlling wetting at structured surfaces

    O Jardim Zoológico enquanto espaço não formal para promoção do desenvolvimento de etapas do raciocínio científico

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    Dissertação (mestrado)—Instituto de Ciências Biológicas, Instituto de Física, Instituto de Química, Faculdade UnB Planaltina, Programa de Pós-Graduação em Ensino de Ciências, Mestrado Profissional em Ensino de Ciências, 2012.Durante muito tempo, e em vários países do mundo, os jardins zoológicos foram locais usados para mera exposição de animais confinados em condições precárias e sujeitos a condicionamentos cruéis, sendo espaços de visitação restritos as castas dominantes. Atualmente, em um numero significativo de instituições, entretenimento deixou de ser a única função desse tipo de ambiente, somando-se a outras importantes funções como conservação, pesquisa e educação. Alguns dados sugerem que o uso desse tipo de espaço não formal de educação como instrumento pedagógico para o aprendizado de conceitos formais de ensino vem se ampliando a cada dia. No entanto, em diversas situações, a prática de campo quando não devidamente planejada e executada, acaba por não surtir o efeito desejado no que diz respeito à apropriação de conceitos. Considerando esse fato, essa pesquisa teórica teve como objetivo principal, a construção de um material didático que busca auxiliar o professor em suas ações, oferecendo sugestões metodológicas para que o aluno vivencie e desenvolva etapas do pensamento cientifico, como observação, registro e analise de dados, inferências, classificação e divulgação, a partir de uma visita orientada ao serpentário do Jardim Zoológico de Brasília. O material e a pesquisa tiveram como referencial a Teoria de Desequilibração proposta por Piaget (1972). Algumas das sugestões metodológicas encontradas nesse recurso didático foram, em parte, resultado de experiências como Professor e Educador do Zôo, podendo esse instrumento vir a ser avaliado em pesquisas futuras. O pequeno número de publicações que trata do uso de zoológicos para o ensino de ciências indica uma evidente necessidade de discussões mais amplas e investigações acerca desse tema, visando conhecer como essa relação se estabelece, e quais são os elementos que justificam a dificuldade, muitas vezes demonstrada pelos educadores, na obtenção de êxitos maiores. ______________________________________________________________________________ ABSTRACTFor a long time, and in many countries, zoos were used for mere exposure of animals confined in squalid conditions and subjected to cruel conditioning, and space restricted visitation dominant castes. Currently a significant number of institutions, entertainment is no longer the sole function of such an environment, adding to other important functions such as conservation, research and education. Some data suggest that the use of such space education week as an educational tool for learning concepts of formal education has been expanding every day. However, in many situations, the practice field when not properly planned and executed, turns out not to have the effect desired with regard to the appropriation of concepts. Considering this fact, this theoretical research aimed to the construction of educational material that seeks to assist the teacher in their actions, providing methodological suggestions for the student to experience and develop steps of scientific thought, such as observation, recording and analyzing objects, inference, classification and disclosure, from a guided visit to the snake collection of Brasilia Zoo. The material and research had as its reference Desequilibração theory proposed by Piaget (1972). Some of the methodological suggestions found in this teaching resource were partly the result of experience as Teacher and Educator of the Zoo, and this instrument may prove to be evaluated in future research. The small number of publications dealing with the use of zoos to science education indicates a clear need for wider discussion and research on this topic, aiming to know how this relationship is established, and what are the elements that justify the difficulty often shown by educators in achieving greater success

    Depredación sobre el erizo diadema aff. antillarum en blanquizales de las Islas Canarias

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    Experimental studies were carried out to determine the effects of predation on populations of the sea urchin Diadema aff. antillarum in barren grounds at the Canary Islands. The studied urchin populations were dominated by small to medium sized individuals (24-38 mm) and were variable in space. Tethering experiments showed that predation rates on D. aff. antillarum were very low and no differences were found between sites. Predation was found to be most intense on juveniles ( 40 mm were not preyed upon whatsoever. We have experimentally demonstrated that there is an absolute predator ‘escape size’ of around 40 mm for D. aff. antillarum individuals in barren grounds. Predation rates obtained for juveniles show that a sufficient number may escape predation and sustain the adult population, maintaining the urchin barren habitat. Recruitment and topographic complexity, rather than predation, seem to determine the structure of urchin populations in barren grounds. We conclude that predation in fished barren grounds of the Canarian Archipelago is not of sufficient magnitude to substantially alter dense urchin populations and cause community-level effects.Se realizaron unos estudios experimentales para valorar el efecto de la depredación sobre las poblaciones del erizo Diadema aff. antillarum, en zonas de blanquizales de las islas Canarias. Las poblaciones de erizos aparecieron dominadas por erizos de tallas pequeñas a medianas (24-38 mm) y resultaron variables en el espacio. Los experimentos de atado mostraron que D. aff. antillarum soporta una presión de depredación muy baja y no se encontraron diferencias entre las estaciones de estudio. La tasa de depredación fue más intensa sobre juveniles (< 20 mm) y adultos de entre 20-30 mm, rango de talla en el que la mayoría de los individuos dejan de tener comportamiento críptico. Los erizos de más de 40 mm de diámetro no fueron depredados en ningún caso. Demostramos experimentalmente la existencia de una talla de escape de D. aff. antillarum frente a la depredación en zonas de blanquizal en torno a los 40 mm. La tasa de depredación obtenida para juveniles indica que un número suficiente debe escapar de la depredación, manteniendo las poblaciones adultas y los blanquizales. Las tasas de reclutamiento y la complejidad topográfica, más que el nivel de depredación, parecen determinar la estructura de las poblaciones de erizos en los blanquizales. Concluimos que la depredación en los fondos rocosos sobreexplotados de las islas Canarias no tiene la magnitud suficiente para alterar substancialmente las densas poblaciones de erizos y causar efectos sobre la comunidad

    Can one predict a drop contact angle?

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    The study of wetting phenomena is of great interest due to the multifaceted technological applications of hydrophobic and hydrophilic surfaces. The theoretical approaches proposed by Wenzel and later by Cassie and Baxter to describe the behavior of a droplet of water on a rough solid are extensively used and continuously updated to characterize the apparent contact angle of a droplet. However, the equilibrium hypothesis implied in these models means that they are not always predictive of experimental contact angles due to the strong metastabilities typically occurring in the wetting of heterogeneous surfaces. A predictive scheme for contact angles is thus urgently needed both to characterize a surface by contact angle measurements and to design super-hydrophobic and -oleophobic surfaces with the desired properties, for example, contact angle hysteresis. In this work, a combination of Monte Carlo simulation and the string method is employed to calculate the free energy profile of a liquid droplet deposited on a pillared surface. For the analyzed surfaces, it is shown that there is only one minimum of the free energy that corresponds to the superhydrophobic wetting state while the wet state can present multiple minima. Furthermore, when the surface roughness decreases the amount of local minima observed in the free energy profile increases. The presented approach clarifies the origin of contact angle hysteresis providing quantitative tools for understanding and controlling wetting at structured surfaces
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