81 research outputs found

    Bird Communities and Feeding Guilds From Three Land Use Types in Kerian River Basin, Perak

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    The objectives of this study were to determine the current bird species present in the study areas and to analyze variation of feeding guilds in different habitat types. Point count and mist-netting methods were used for bird census in SF and OP, while only point count method was used in PF. Feeding guilds were determined for each species recorded. A total of 183 species representing 49 families were recorded at all study sites. Secondary forest scored 106 species, followed by PF with 70 species and OP with 58 species. The highest abundance of bird families observed in SF was Pycnonotidae (26.65%), Hemiprocnidae (19.77%) and Muscicapidae (7.10%); in OP, Pycnonotidae (21.59%), Muscicapidae (19.12%) and Sturnidae (17.95%); in PF, Ardeidae (29.09%), Sturnidae (10.15%) and Hirundinidae (7.86%). Alternative hypothesis established that the abundance of species is different across habitat types, F(2,105) = 99.83, p < 0.05. Eight feeding guilds were identified in paddy field and seven in both secondary forest and oil palm plantation. If forests were converted to OP feeding guild could possibly change with a decreased in insectivore, insectivore-frugivore, insectivore-nectarivore and frugivore species; and increased in carnivore, grainivore and omnivore species. If forests were converted to PF feeding guild could possibly change with a decreased in insectivore, insectivore-frugivore and frugivore species; and increased in carnivore, insectivorenectarivore, insectivore-grainivore, grainivore and omnivore species. Comparison between SF and OP with Mann-Whitney U-test showed significant differences in six feeding guilds, including insectivore, insectivore-frugivore, insectivore-nectarivore, frugivore, grainivore and omnivore. Comparison between SF and PF showed significant differences in five feeding guilds, comprising of carnivore, insectivore-grainivore, frugivore, grainivore and omnivore. Comparison between OP and PF showed all feeding guilds to be significantly different. Complex vegetation in forestoffers more niches, with higher plant and insect diversity to support more bird species. In contrast, PF, a temporary wetland, support predominantly various waterbirds and migratory species

    Learning to Communicate: A Machine Learning Framework for Heterogeneous Multi-Agent Robotic Systems

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    We present a machine learning framework for multi-agent systems to learn both the optimal policy for maximizing the rewards and the encoding of the high dimensional visual observation. The encoding is useful for sharing local visual observations with other agents under communication resource constraints. The actor-encoder encodes the raw images and chooses an action based on local observations and messages sent by the other agents. The machine learning agent generates not only an actuator command to the physical device, but also a communication message to the other agents. We formulate a reinforcement learning problem, which extends the action space to consider the communication action as well. The feasibility of the reinforcement learning framework is demonstrated using a 3D simulation environment with two collaborating agents. The environment provides realistic visual observations to be used and shared between the two agents.Comment: AIAA SciTech 201

    Aspectos clínicos y epidemiológicos de los síndromes de Apert y Crouzon en España

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    Epidemiología y Teratología: Resultados sobre los datos del ECEMCApert and Crouzon syndromes are the most frequent ones among those syndromes with craniosynostosis. We have used data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), to analyze some clinical and epidemiological characteristics of both syndromes. A total of 19 cases of Apert and 21 cases of Crouzon syndromes were identified among 1,914,726 liveborn infants. Their birth prevalence has diminished along the time although the decrease is only statistically significant for Crouzon syndrome. Mean parental ages, and mean differences between the parental ages, are significantly higher in Apert cases than in controls, what is indicating a relationship between paternal age and mutations for this syndrome. The differences between the parental ages of Crouzon cases and controls are not statistically significant. All the cases with Apert syndrome of our series were the first occurrence in the family, while 38.10% of the Crouzon cases were familial. We also observed a significant increasing linear trend in the frequency of infants with Apert syndrome, with the increasing paternal age, which is more noticeable since the age of 35 years. However, this is not observed for Crouzon cases whether sporadic or familial. Regarding the clinical aspects, Apert syndrome is more frequently associated to other defects than Crouzon syndrome. With respect to the affectation of hands in the Apert cases, the most frequent defect was the so-called "mitten hand", wich was present in 50% of our cases. In 28.57% the first finger was separated from the rest that are fused. Interestingly, in one case only the fifth finger was separated for the other four that remain fused.N

    On Vastness and Variability: Cultural Transmission, Historicity, and the Paleoindian Record in Eastern South America

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