525 resultados para dendrobatid frog


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Proyecto de Educación Primaria desarrollado por nueve profesores en el CP 'La Goleta'. Los objetivos fueron: adecuar el Diseño Curricular Base al entorno socio-cultural de los alumnos, en el área de Inglés, elaborar y poner en práctica recursos didácticos, desarrollar estrategias de trabajo en equipo, como recurso para lograr la participación de todos los alumnos, adecuar el desarrollo curricular de las lenguas extranjeras, para conseguir el aprendizaje autónomo y, llevar a cabo la coordinación intercentro de los profesores y alumnos implicados. La dinámica de trabajo de las sesiones del grupo se ajustó al siguiente esquema: lectura del acta de la sesión anterior, información de interés de material en pequños grupos, según niveles y, puesta en común del trabajo desarrollado. La experiencia se basó en los siguientes centros de interés: 'Words and numbers', 'Colours', 'Shapes', 'Make a frog (prepositions)', 'My body', 'My face', 'My family', 'Happy birthday', 'Food', 'Animals' y, 'Merry Christmas'. Cada centro de interés contiene un proyecto que centra el trabajo del tema y se enlaza con otras áreas del currículum, favorecienco así la autonomía en el aprendizaje y la interacción. Los proyectos correspondientes a cada centro de interés fueron: 'Make a collage (con material auténtico)', 'Make a collage (de un color determinado)', 'Make a picture dictionary', 'Make a frog', 'Make a pupet', 'Make a mask', 'Make a birthday card', 'Make your food diary', y 'Make a Christmas card'. Sobre cada centro de interés se elaboró una unidad didáctica que reflejase los objetivos, contenidos, actitudes, materiales y evaluación, así como la programación diaria por sesiones con las actividades secuenciadas. Los resultados fueron positivos pues: se cumplieron los objetivos propuestos, el buen desarrollo del trabajo en equipo, la coordinación entre centros, el enriquecimiento de la vida en el aula, la diversidad de actividades, la práctica docente más activa y, el trabajo del alumno más activo.

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Estudiar el desarrollo de los mecanismos lingüísticos que utilizan los niños que están aprendiendo el español como lengua materna, para marcar nociones temporales y aspectuales, con especial atención a la morfología verbal, con el fin de poder determinar si los numerosos problemas que tienen los niños y chicos en la escuela a la hora de emplear los verbos, pudiera explicarse en términos de su adquisición. Parte de 2 hipótesis generales: A) Los sujetos menores (3:6 años) usarán varias de las formas que el español les brinda para marcar nociones temporales y aspectuales. B) Los niños mostrarán una sensibilidad hacia las características particulares de su lengua. 60 sujetos, 48 niños de edades comprendidas entre los 3 años y 6 meses y los 10 años, y un grupo de 12 adultos. Se han establecido 4 grupos de niños por edad, con 12 sujetos en cada uno de ellos (6 niños y 6 niñas). Todos ellos pertenecen a un nivel socioeconómico medio y tienen el castellano como única lengua. La investigación se ha organizado en dos partes. En la primera, se abordan las nociones de tiempo y aspecto desde una perspectiva lingüística teórica y se revisan los estudios sobre tiempo y aspecto desde una perspectiva psicolingüística evolutiva. En la segunda, se incluye el trabajo experimental, con la presentación de los objetivos e hipótesis, el método y el análisis de los resultados. Se ha optado por tomar como punto de partida los diferentes mecanismos lingüísticos (morfológicos, sintácticos y léxicos) que emplean los sujetos para marcar distintas nociones temporales y aspectuales. El material empleado ha sido un cuento con 24 dibujos sin texto (¿frog, where are you?). Y todos los participantes narran el cuento en sesiones individuales. Cuento. Porcentajes, tablas. Ya desde los 3 años los niños españoles son capaces de incorporar casi todas las distinciones aspectuales y temporales del español, y cuando no disponen de los mecanismos sintácticos adultos, compensan esa carencia con otro tipo de mecanismos, especialmente morfológicos. No obstante, hasta los 5 años no podemos considerar que comienza a desarrollarse la capacidad narrativa del niño. Los resultados vienen a demostrar que la morfología verbal está al alcance de los niños antes de que empiecen la instrucción en gramática. Por tanto, la razón de la dificultad que los niños y chicos tienen en el uso correcto de los verbos, debe buscarse fuera del ámbito del desarrollo del lenguaje, quizá en la toma de conciencia de las reglas gramaticales, en la metalingüística. Según la investigadora, la clase de gramática debe convertirse en la incorporación de actividades que supongan un entrenamiento metalingüístico para los alumnos, a través de la reflexión de los rasgos y elementos de su lengua, a través de la formulación y contrastación de 'hipótesis', a través de la búsqueda de ejemplos y contraejemplos, etc..

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The main theme of the ICTOP'94 Lisbon meeting is museum personnel training for the universal museum. At the very beginning it is important to identify what the notion universal museum can cover. It is necessary to underline the ambiguity of the term. On the one hand, the word 'universal' can be taken to refer to the variety of collected museum materials or museum collections, on the other hand it could refer to the efforts of the museum to be active outside the museum walls in order to achieve the integration of the heritage of a certain territory into a museological system. 'Universal' could also refer to the "new dimensions of reality: the fantastic reality of the virtual images, only existing in the human brain" (Scheiner 1994:7), which is very close to M. McLuhan's view of the world as a 'global village'. Thus, what is universal could be taken as being common and available to all the people of the world. 'Universal' can imply also the radical broadening of the concept of object: "mountain, silex, frog, waterfonts, stars, the moon ... everything is an object, with due fluctuations" (Hainard in Scheiner 1994: 7), which will cause the total involvement of the human being into his/her physical and spiritual environment. In the process of universalization, links between cultural and natural heritage and their links with human beings become more solid, helping to create a strong mutual interdependence.

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We analyze a fully discrete spectral method for the numerical solution of the initial- and periodic boundary-value problem for two nonlinear, nonlocal, dispersive wave equations, the Benjamin–Ono and the Intermediate Long Wave equations. The equations are discretized in space by the standard Fourier–Galerkin spectral method and in time by the explicit leap-frog scheme. For the resulting fully discrete, conditionally stable scheme we prove an L2-error bound of spectral accuracy in space and of second-order accuracy in time.

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Timediscretization in weatherandclimate modelsintroduces truncation errors that limit the accuracy of the simulations. Recent work has yielded a method for reducing the amplitude errors in leap-frog integrations from first-order to fifth-order.This improvement is achieved by replacing the Robert–Asselin filter with the Robert–Asselin–Williams (RAW) filter and using a linear combination of unfiltered and filtered states to compute the tendency term. The purpose of the present article is to apply the composite-tendency RAW-filtered leapfrog scheme to semi-implicit integrations. A theoretical analysis shows that the stability and accuracy are unaffected by the introduction of the implicitly treated mode. The scheme is tested in semi-implicit numerical integrations in both a simple nonlinear stiff system and a medium-complexity atmospheric general circulation model and yields substantial improvements in both cases. We conclude that the composite-tendency RAW-filtered leap-frog scheme is suitable for use in semi-implicit integrations.

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The pipe sizing of water networks via evolutionary algorithms is of great interest because it allows the selection of alternative economical solutions that meet a set of design requirements. However, available evolutionary methods are numerous, and methodologies to compare the performance of these methods beyond obtaining a minimal solution for a given problem are currently lacking. A methodology to compare algorithms based on an efficiency rate (E) is presented here and applied to the pipe-sizing problem of four medium-sized benchmark networks (Hanoi, New York Tunnel, GoYang and R-9 Joao Pessoa). E numerically determines the performance of a given algorithm while also considering the quality of the obtained solution and the required computational effort. From the wide range of available evolutionary algorithms, four algorithms were selected to implement the methodology: a PseudoGenetic Algorithm (PGA), Particle Swarm Optimization (PSO), a Harmony Search and a modified Shuffled Frog Leaping Algorithm (SFLA). After more than 500,000 simulations, a statistical analysis was performed based on the specific parameters each algorithm requires to operate, and finally, E was analyzed for each network and algorithm. The efficiency measure indicated that PGA is the most efficient algorithm for problems of greater complexity and that HS is the most efficient algorithm for less complex problems. However, the main contribution of this work is that the proposed efficiency ratio provides a neutral strategy to compare optimization algorithms and may be useful in the future to select the most appropriate algorithm for different types of optimization problems.

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Diverse invertebrate and vertebrate species live in association with plants of the large Neotropical family Bromeliaceae. Although previous studies have assumed that debris of associated organisms improves plant nutrition, so far little evidence supports this assumption. In this study we used isotopic ((15)N) and physiological methods to investigate if the treefrog Scinax hayii, which uses the tank epiphytic bromeliad Vriesea bituminosa as a diurnal shelter, contributes to host plant nutrition. In the field, bromeliads with frogs had higher stable N isotopic composition (delta(15)N) values than those without frogs. Similar results were obtained from a controlled greenhouse experiment. Linear mixing models showed that frog feces and dead termites used to simulate insects that eventually fall inside the bromeliad tank contributed, respectively, 27.7% (+/- 0.07 SE) and 49.6% (+/- 0.50 SE) of the total N of V. bituminosa. Net photosynthetic rate was higher in plants that received feces and termites than in controls; however, this effect was only detected in the rainy, but not in the dry season. These results demonstrate for the first time that vertebrates contribute to bromeliad nutrition, and that this benefit is seasonally restricted. Since amphibian-bromeliad associations occur in diverse habitats in South and Central America, this mechanism for deriving nutrients may be important in bromeliad systems throughout the Neotropics.

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The matrix-tolerance hypothesis suggests that the most abundant species in the inter-habitat matrix would be less vulnerable to their habitat fragmentation. This model was tested with leaf-litter frogs in the Atlantic Forest where the fragmentation process is older and more severe than in the Amazon, where the model was first developed. Frog abundance data from the agricultural matrix, forest fragments and continuous forest localities were used. We found an expected negative correlation between the abundance of frogs in the matrix and their vulnerability to fragmentation, however, results varied with fragment size and species traits. Smaller fragments exhibited stronger matrix-vulnerability correlation than intermediate fragments, while no significant relation was observed for large fragments. Moreover, some species that avoid the matrix were not sensitive to a decrease in the patch size, and the opposite was also true, indicating significant differences with that expected from the model. Most of the species that use the matrix were forest species with aquatic larvae development, but those species do not necessarily respond to fragmentation or fragment size, and thus affect more intensively the strengthen of the expected relationship. Therefore, the main relationship expected by the matrix-tolerance hypothesis was observed in the Atlantic Forest; however we noted that the prediction of this hypothesis can be substantially affected by the size of the fragments, and by species traits. We propose that matrix-tolerance model should be broadened to become a more effective model, including other patch characteristics, particularly fragment size, and individual species traits (e. g., reproductive mode and habitat preference).

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Anuran amphibians exhibit different patterns of energy substrate utilization that correlate with the intensity of vocal and locomotor activities. Given the remarkable differences among species in breeding and feeding strategies, and the different ways energy is used in the whole animal, the suggested correlations between calling and locomotor behavior and the level of energy substrates in the muscles responsible for such activities are more complex than previously reported. We explored the relationships between calling and locomotor behavior and energy supply to trunk and hindlimb muscles, respectively, within the ecologically diverse tree-frog genus Scinax. Specifically, we measured the relative amount of carbohydrates and lipids in these two groups of muscles, and in the liver of three species of Scinax that differ in vocal and locomotor performance, and compared our results with those of two other species for which comparable data are available. We also compared the contents of lipids and carbohydrates of conspecific males collected at the beginning and after 4 h of calling activity. The stomach content to potential feeding opportunities across species was also assessed in both groups of males. Scinax hiemalis and S. rizibilis exhibit comparatively low and episodic calling during long periods of activity whereas S. crospedospilus calls at higher rates over shorter periods. Male S. hiemalis had highest levels of trunk muscle glycogen followed by those of S. rizilbilis and S. crospedospilus, respectively. There was no correlation between total lipid content in trunk muscle and calling rate among different species, suggesting that other metabolic aspects may be responsible for the energetic support for vocal activity. The levels of lipids and carbohydrates in trunk and hindlimb muscles and liver of males collected at the beginning and 4 h into the calling period were similar across species, so the extent of energetic reserves does not appear to constrain vocal or locomotor activity. Finally, we found exceptionally high levels of carbohydrates and lipids in the liver of S. rizibilis, a trait perhaps related to a long and demanding breeding period.

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Cycloramphus jordanensis was described based on a single preserved specimen from Campos do Jordao (22 degrees 44` S ,45 degrees 35` W), State of Sao Paulo, Brazil. While examining the holotype; we noticed the presence of toe and tarsal fringes. Because these characters are absent in Cycloramphus, we suspected that the species was mistakenly placed in the genus. X-ray images of the holotype revealed T-shaped terminal phalanges and fang-like teeth. Together with the presence of toe and tarsal fringes, these characters squarely place the specimen in the genus Megaelasia. Considering the striking niche differences between Cycloramphus and Megaclosia, we expect the new combination will facilitate location of new individuals of this rare frog.

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Brachycephalus hermogenesi is an endemic leaf litter inhabitant of the Atlantic forest of southeastern Brazil, whose original distribution included a restricted area near the boundaries of the States of Sao Paulo and Rio de Janeiro. We were surprised to find out, while conducting herpetofaunal surveys at Estacao Biologica de Boraceia (EBB), that the background forest insect-like sound we have been searching for corresponded to calling individuals of the species. Males call during the day at high densities, hidden under the leaf litter. Individuals do not answer playback, seem to move very infrequently, and seem to ignore nearby calling activity. We gathered data on annual and daily vocal activity of the species at EBB, observing a total of 1,549 calls given by 31 focal individuals in November 2003 and 2005. The call varies from short single note calls to calls composed of groups of two to seven similar notes emitted at regular intervals. We also extend the known distribution of the species southward to the State of Sao Paulo.

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We report here the discovery of a new species of frog associated to the open areas of the highlands of the Parque Nacional da Serra dos Orgaos. The new species, Cycloramphus organensis is characterized by a unique skin texture, medium size ( maximum male and female SVL 26.4 mm and 33.3 mm respectively), dorsal surfaces uniformly brick red colored, uniformly areolate skin on dorsum, pupil horizontal, iris with a menisc on upper margin; no fleshy tubercles on eyelid, tympanic annulus concealed beneath skin, macroglands not visible externally, fingers and toes without fringes and webs; supernumerary palmar and plantar tubercles absent, nuptial spines absent. Despite the presence of an iris menisc, a character shared by frogs of both genera Cycloramphus and Zachaenus Cope, the combination of morphological characters is so unique that the allocation of the species to any of these genera remains ambiguous. Consequently, we used additional molecular-based phylogenetic analyses to ascertain the position of the new taxon. The new species proved to be embedded within the genus Cycloramphus.

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A new species of the tree toad genus Dendrophryniscus is described from a rainforest habitat at Parque Nacional de Serra das Lontras, municipality of Arataca, southern Bahia, Brazil. Dendrophryniscus oreites sp. nov. is related to the Atlantic forest brevipollicatus group by hand morphology, skin texture, ventral coloration and bromelicolous habits. The new species differs from related species by having a larger size, warty skin, inner finger reduced with presence of a dark nuptial pad in males, and a yellowish coloration with discrete dorsal pattern. This discovery highlights the importance of southern Bahia in terms of conservation, and for our understanding of the evolution of the frog diversity within the Atlantic Rainforest.

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Analysis of the phylogenetic relationships among trypanosomes from vertebrates and invertebrates disclosed a new lineage of trypanosomes circulating among anurans and sand flies that share the same ecotopes in Brazilian Amazonia. This assemblage of closely related trypanosomes was determined by comparing whole SSU rDNA sequences of anuran trypanosomes from the Brazilian biomes of Amazonia, the Pantanal, and the Atlantic Forest and from Europe, North America, and Africa, and from trypanosomes of sand flies from Amazonia. Phylogenetic trees based on maximum likelihood and parsimony corroborated the positioning of all new anuran trypanosomes in the aquatic clade but did not support the monophyly of anuran trypanosomes. However, all analyses always supported four major clades (An01-04) of anuran trypanosomes. Clade An04 is composed of trypanosomes from exotic anurans. Isolates in clades An01 and An02 were from Brazilian frogs and toads captured in the three biomes studied, Amazonia, the Pantanal and the Atlantic Forest. Clade An01 contains mostly isolates from Hylidae whereas clade An02 comprises mostly isolates from Bufonidae; and clade An03 contains trypanosomes from sand flies and anurans of Bufonidae, Leptodactylidae, and Leiuperidae exclusively from Amazonia. To our knowledge, this is the first study describing morphological and growth features, and molecular phylogenetic affiliation of trypanosomes from anurans and phlebotomines, incriminating these flies as invertebrate hosts and probably also as important vectors of Amazonian terrestrial anuran trypanosomes.

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We study random walks systems on Z whose general description follows. At time zero, there is a number N >= 1 of particles at each vertex of N, all being inactive, except for those placed at the vertex one. Each active particle performs a simple random walk on Z and, up to the time it dies, it activates all inactive particles that it meets along its way. An active particle dies at the instant it reaches a certain fixed total of jumps (L >= 1) without activating any particle, so that its lifetime depends strongly on the past of the process. We investigate how the probability of survival of the process depends on L and on the jumping probabilities of the active particles.