251 research outputs found

    Sobre Neoasterolepisma wasmanni (Moniez, 1894) y la identidad de Lepisma iberica Stach, 1930, con descripción de dos nuevas especies ibéricas de Neoasterolepisma (Apterygota: Zygentoma: Lepismatidae)

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    En este trabajo se exponen las razones por las que Lepisma iberica sensu Stach, 1930, debe ser sinonimizada con Neoasterolepisma wasmanni (Moniez, 1894) ya que los ejemplares de la especie descrita por Stach se corresponden en realidad con juveniles de la de Moniez. Al mismo tiempo se describen dos nuevas especies del SO de la Península Ibérica, Neoasterolepisma hesperica n. sp. y Neoasterolepisma delator n. sp., basadas en formas que hasta la fecha se habían determinado como Lepisma iberica o Neoasterolepisma iberica. Se discuten las diferencias de estas nuevas especies entre sí y con otras especies próximas.Reasons why Lepisma iberica sensu Stach, 1930 must be treated as a synonym of Neoasterolepisma wasmanni (Moniez, 1894) are discussed, emphasizing that the insects described by Stach as a new species are, in fact, young specimens belonging to the species described by Moniez. At the same time, two new species found in the Southwestern regions of the Iberian Peninsula are described: Neoasterolepisma hesperica sp. n. and N. delator sp. n. These two taxa had been determined until now as Lepisma iberica or Neoasterolepisma iberica; they are compared between themselves and with other similar Neoasterolepisma

    Neoasterolepisma pallida n. sp. de Lepismatidae (Insecta: Zygentoma) del sureste de España

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    Se describe una nueva especie de Lepismatidae hallado en las provincias de Murcia, Alicante, Valencia y Albacete, perteneciente al género Neoasterolepisma: N. pallida n. sp. Se indican las principales diferencias con especies afines, destacando que en los machos de esta nueva especie las tibias posteriores no están modificadas, lo que sí sucede en todos los Neoasterolepisma ibéricos excepto N. curtiseta. Presenta, como peculiaridad, una notable modificación de la quetotaxia del artejo distal del palpo labial.A new species of Lepismatidae of the genus Neoasterolepisma, N. pallida sp. n., is described from the Murcia, Alicante, Valencia and Albacete provinces in Spain. The main differences between the new species and the most closely related ones are pointed out. The main morphological feature of this new species is the modification of the chaetotaxy of the last article of the lapial palp, and the absence of modifications in the third tibia of the males, whereas the modification of this leg article in males is normal in the species of Neoasterolepisma of the Iberian Peninsula except for N. curtiset

    Vibrational and stochastic resonances in two coupled overdamped anharmonic oscillators

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    We study the overdamped version of two coupled anharmonic oscillators under the influence of both low- and high-frequency forces respectively and a Gaussian noise term added to one of the two state variables of the system. The dynamics of the system is first studied in the presence of both forces separately without noise. In the presence of only one of the forces, no resonance behaviour is observed, however, hysteresis happens there. Then the influence of the high-frequency force in the presence of a low-frequency, i.e. biharmonic forcing, is studied. Vibrational resonance is found to occur when the amplitude of the high-frequency force is varied. The resonance curve resembles a stochastic resonance-like curve. It is maximum at the value of gg at which the orbit lies in one well during one half of the drive cycle of the low-frequency force and in the other for the remaining half cycle. Vibrational resonance is characterized using the response amplitude and mean residence time. We show the occurrence of stochastic resonance behaviour in the overdamped system by replacing the high-frequency force by Gaussian noise. Similarities and differences between both types of resonance are presented.Comment: 22 pages, 13 figure

    A DFT Approach for Methanol Synthesis via Hydrogenation of CO on Gallia, Ceria and ZnO surfaces

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    A systematic theoretical study of the consecutive hydrogenation reactions of the CO molecule for the methanol synthesis catalyzed by different oxides of Zn, Ce and Ga is reported in this work. First, the CO hydrogenation with the formation of formyl species (HCO) was analyzed, followed by the successive hydrogenations that lead to formaldehyde (H2CO), methoxy (H3CO) and, finally, methanol (H3COH). The co-adsorption with H, in almost all the intermediate species, allows the corresponding hydrogenation reaction. Oxygen vacancies promote the reactivity in the generation of both formaldehyde and methoxy species. The formation of these species involves an important geometric difference between the initial and the final states, leading to high activation barriers. Comparing the surfaces studied in this work, we found that ZnO (0001)vacO has shown to be of a greater interest for methanol synthesis. However, the foregoing is not the most relevant of our results, but, instead, that the Brönsted Evans Polanyi (BEP) relationships between the initial or the final states and the transition states (TS) allowed to find a very good correlation between surface structure and reactivity.Fil: Reimers, Walter Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; ArgentinaFil: Zubieta, Carolina Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Baltanas, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Branda, Maria Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Física del Sur. Universidad Nacional del Sur. Departamento de Física. Instituto de Física del Sur; Argentin

    Pheromone-induced morphogenesis improves osmoadaptation capacity by activating the HOG MAPK pathway

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    Environmental and internal conditions expose cells to a multiplicity of stimuli whose consequences are difficult to predict. We investigate the response to mating pheromone of yeast cells adapted to high osmolarity. Events downstream of pheromone binding involve two mitogen-activated protein kinase (MAPK) cascades: the pheromone response (PR) and the cell wall integrity (CWI) response. Although the PR MAPK pathway shares components with a third MAPK pathway, the high osmolarity (HOG) response, each one is normally only activated by its cognate stimulus, a phenomenon called insulation. We found that in cells adapted to high osmolarity, PR activated the HOG pathway in a pheromone- and osmolarity-dependent manner. Activation of HOG by the PR was not due to loss of insulation, but rather a response to a reduction in internal osmolarity, which resulted from an increase in glycerol release caused by the PR. By analyzing single-cell time courses, we found that stimulation of HOG occurred in discrete bursts that coincided with the "shmooing" morphogenetic process. Activation required the polarisome, the CWI MAPK Slt2, and the aquaglyceroporin Fps1. HOG activation resulted in high glycerol turnover, which improved adaptability to rapid changes in osmolarity. Our work shows how a differentiation signal can recruit a second, unrelated sensory pathway to fine-tune yeast response in a complex environment.Fil: Baltanas, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas . Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Bush, Alan. Consejo Nacional de Investigaciones Científicas y Técnicas . Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Couto, Alicia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Durrieu, Lucía. Consejo Nacional de Investigaciones Científicas y Técnicas . Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Hohmann, Stefan. University of Gothenburg. Department of Cell and Molecular Biology; SueciaFil: Colman Lerner, Alejandro Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas . Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

    Resonance phenomena in discrete systems with bichromatic input signal

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    We undertake a detailed numerical study of the twin phenomena of stochastic and vibrational resonance in a discrete model system in the presence of bichromatic input signal. A two parameter cubic map is used as the model that combines the features of both bistable and threshold settings. Our analysis brings out several interesting results, such as, the existence of a cross over behaviour from vibrational to stochastic resonance and the possibility of using stochastic resonance as a filter for the selective detection/transmission of the component frequencies in a composite signal. The study also reveals a fundamental difference between the bistable and threshold mechanisms with respect to amplification of a multi signal input.Comment: 17 pages, 16 figures, submitted to European Physical Journa

    Reinforcement Learning for StarCraft II

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    Trabajo Fin de Grado en Desarrollo de Videojuegos, Facultad de Informática UCM, Departamento de Ingeniería del Software e Inteligencia Artificial, Curso 2020/2021En este Trabajo Fin de Grado se estudian distintas técnicas de aprendizaje por refuerzo, una rama del aprendizaje automatico que ha demostrado en los últimos años ser una de las opciones mas populares dentro de este ámbito. DeepMind ha aplicado algoritmos de aprendizaje por refuerzo en distintos videojuegos, poniendo de relieve la utilidad de estas aplicaciones para contribuir al avance de la investigación en el campo del aprendizaje automático. En este marco, la finalidad de este trabajo es la aplicación de técnicas de aprendizaje por refuerzo en distintos entornos del videojuego StarCraft II. Las características de este videojuego, en concreto el hecho de que incluye tomas de decisiones a distintos niveles con información parcial del estado del entorno, suponen grandes ventajas a la hora de aplicar técnicas de aprendizaje automático respecto a otros videojuegos. Tras profundizar en el estudio de los algoritmos de aprendizaje por refuerzo QLearning y Deep Q-Learning con objeto de entender su funcionamiento correctamente, ambos algoritmos se han implementado en minijuegos de StarCraft II. Esta aplicación ha consistido en el desarrollo de jugadores automáticos que aprenden varios objetivos enfocados a la toma de decisiones a distintos niveles en videojuegos RTS. Para ello,se ha realizado un estudio sobre las estrategias habituales en estos videojuegos y se ha implementado una arquitectura reutilizable que permite intercambiar los distintos agentes y entornos de manera sencilla. Finalmente, se analizan los resultados obtenidos en los diferentes experimentos realizados y se presentan las conclusiones extraídas a partir de dichos resultados.In this Bachelor’s Degree Final Proyect, different reinforcement learning techniques are studied, a branch of machine learning that has proven in recent years to be one of the most popular options in this field. DeepMind has applied reinforcement learning algorithms in different videogames, highlighting the usefulness of these applications to contribute to the advancement of research in the field of machine learning. In this framework, the purpose of this work is the application of reinforcement learning techniques in different environments of the StarCraft II videogame. The characteristics of this video game, specifically the fact that it includes decision-making at different levels with partial information about the state of the environment, represent great advantages when applying machine learning techniques compared to other videogames. After delving into the study of Q-Learning and Deep Q-Learning reinforcement learning algorithms in order to correctly understand how they work, both algorithms have been implemented in StarCraft II minigames. This application has consisted of the development of automatic players that learn various objectives focused on decision-making at different levels in RTS video games. To do this, a study has been carried out on the usual strategies in these video games and a reusable architecture has been implemented that allows the different agents and environments to be exchanged easily. Finally, the results obtained in the different experiments carried out are analyzed and the conclusions drawn from these results are presented.Depto. de Ingeniería de Software e Inteligencia Artificial (ISIA)Fac. de InformáticaTRUEunpu

    Developing documents for practical sessions in Zoology

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    La implantación del sistema unificado de créditos (E.C.T.S.) implica nuevos planteamientos por parte del profesorado al elaborar la programación teórico-práctica de las diferentes asignaturas. Con la elaboración de los protocolos prácticos de zoología pretendemos alcanzar los objetivos siguientes: 1. Proveer a los alumnos de material didáctico básico y complementario a la información impartida en las sesiones prácticas. 2. Proporcionar una perspectiva amplia de diferentes aspectos prácticos de la zoología. 3. Familiarizar a los alumnos con las fuentes (complementarias) de información y los procedimientos de acceso a diferentes tipos de material biológico. 4. Favorecer el trabajo personal y de grupo, enfatizando diferentes aspectos biológicos necesarios para la asimilación de los contenidos prácticos de la asignatura. 5. Facilitar la preparación de las pruebas prácticas que los alumnos han de realizar. En el curso académico 2003/2004 nos fue concedido un primer proyecto docente que nos permitió preparar contenidos correspondientes a la práctica “Introducción a las técnicas de campo y de laboratorio en Zoología”. A partir de esta primera experiencia hemos desarrollado varios proyectos docentes que nos han permitido preparar materiales y contenidos prácticos de los principales taxones de animales invertebrados: Poríferos y Cnidarios. Platelmintos, Nematodos y Anélidos. Artrópodos. Moluscos. Equinodermos. La preparación de estos contenidos nos ha obligado a realizar desplazamientos así como a solicitar colaboraciones de diversas instituciones, por ejemplo, al Museo Nacional de Ciencias Naturales de Madrid. Los protocolos están diseñados de forma que fomentan la labor individual y auto-formativa del alumnado, así como el estudio en grupo. Todo está encaminado hacia una completa preparación y correcta adecuación al nuevo sistema educativo. Las presentaciones multimedia están a disposición del alumnado gracias a las posibilidades que ofrece la web de la Universidad de Córdoba.The implementation of the unified credit system (ECTS) involves new approaches by teachers in the development of both theoretical and practical curricula of different subjects. With the development of practical zoology documents we aim to achieve the following objectives: 1. To provide the students with basic educational materials, and complementary information to the practical sessions. 2. To provide a broad overview of different practical aspects of zoology. 3. To familiarize students with additional sources of information and procedures for access to different types of biological material. 4. To encourage personal and group work, emphasizing different biological aspects, which are necessary for the understanding of the practical contents of the subjects. 5. To assist in the preparation of exams that students must perform. In the academic course 2003/2004 we were awarded with a first educational project that allowed us to prepare content for the practice "Introduction to field and lab techniques in Zoology". From this first experience we have developed several educational projects that have allowed us to prepare materials and practical content of the main taxa of invertebrates: Sponges and Cnidarians. Flatworms, Nematodes and Annelids. Arthropods. Molluscs. Echinoderms. The preparation of these materials has lead us to make trips and to request contributions from various institutions, for example, the Museo Nacional de Ciencias Naturales in Madrid. The protocols are designed in ways that encourage individual work and selftraining of students, and study groups. Everything is aimed to the complete preparation and fair adaptation to the new educational system. Multimedia presentations are available to students thanks to the possibilities offered by the website of the University of Cordoba

    Contribution to the knowledge of continental ostracod from Chile

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    Our knowledge of continental ostracods in South America is still in its infancy with a total of only 260 species (MARTENS & BEHEN, 1994). Particularly in Chile, it is still scarce and scattered, with large voids in the taxonomy and distribution. In Chile, the first records were reported by DADAY (1902), BREHM (1934) and LÖFFLER (1961a, b). Later, SCHWALB & BURNS (1999) cited species of Limnocytheridae and KARANOVIC (2012) provided new records of Candonidae from Chile. The main objective of this work is to provide a checklist of ostracods in Chile with updated distributional records.Fil: Cardenas, Javiera. Universidad de Concepción; ChileFil: Baltanas, Angel. Universidad Autónoma de Madrid; EspañaFil: Figueroa, Ricardo. Universidad de Concepción; ChileFil: Cusminsky, Gabriela Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; ArgentinaFil: Laprida, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos; ArgentinaFil: Ramon Mercau, Josefina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Alvarez, Denisse. Universidad de Concepción; ChileFil: Urrutia, Roberto. Universidad de Concepción; Chil
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