27 research outputs found
Hydrological Uncertainty and Hydropower: New Methods to Optimize the Performance of the Plantâ
Abstract Hydrological uncertainty due to daily flow variability and to the effect of climate change on water resources is a critical topic in the feasibility evaluations of hydro-power projects, especially for run-of-river power plant. The effect produced by these factors on the annual energy output of such type of plant was investigated. Empirical methods to improve the performance of the plant are proposed, which enable the choice of the most suitable design flow (Q d ) according to the hydrological features of the river, to the frequency of dry and wet years in the basin and to the target energy production
Spontaneous Learning of Visual Structures in Domestic Chicks
Effective communication crucially depends on the ability to produce and recognize structured signals, as apparent in language and birdsong. Although it is not clear to what extent similar syntactic-like abilities can be identified in other animals, recently we reported that domestic chicks can learn abstract visual patterns and the statistical structure defined by a temporal sequence of visual shapes. However, little is known about chicks’ ability to process spatial/positional information from visual configurations. Here, we used filial imprinting as an unsupervised learning mechanism to study spontaneous encoding of the structure of a configuration of different shapes. After being exposed to a triplet of shapes (ABC or CAB), chicks could discriminate those triplets from a permutation of the same shapes in different order (CAB or ABC), revealing a sensitivity to the spatial arrangement of the elements. When tested with a fragment taken from the imprinting triplet that followed the familiar adjacency-relationships (AB or BC) vs. one in which the shapes maintained their position with respect to the stimulus edges (AC), chicks revealed a preference for the configuration with familiar edge elements, showing an edge bias previously found only with temporal sequences
Os efeitos da Lei de Responsabilidade Fiscal no endividamento dos municĂpios do PiauĂ
RepresentaçÔes sobre segurança alimentar e nutricional nos discursos de um Conselho de Alimentação Escolar
Variance of hand and angular trajectories during tracking arm movements of patients with parkinson disease and healthy control
Variance of hand and angular trajectories during tracking arm movements of patients with parkinson disease and healthy contro
The role of prosody in infants\u2019 preference for speech: a comparison between speech and birdsong
Speech preferences emerge very early in infancy, pointing to a special status for speech in auditory processing and a crucial role of prosody in driving infant preferences. Recent theoretical models suggest that infant auditory perception may initially encompass a broad range of human and nonhuman vocalizations, then tune in to relevant sounds for the acquisition of species-specific communication sounds. However, little is known about sound properties eliciting infants\u2019 tuning-in to speech. To address this issue, we presented a group of 4-month-olds with segments of non-native speech (Mandarin Chinese) and birdsong, a nonhuman vocalization that shares some prosodic components with speech. A second group of infants was presented with the same segment of birdsong paired with Mandarin played in reverse. Infants showed an overall preference for birdsong over non-native speech. Moreover, infants in the Backward condition preferred birdsong over backward speech whereas infants in the Forward condition did not show clear preference. These results confirm the prominent role of prosody in early auditory processing and suggest that infants\u2019 preferences may privilege communicative vocalizations featured by certain prosodic dimensions regardless of the biological source of the sound, human or nonhuma
Integração na criação de frangos de corte na microrregião de Viçosa - MG: viabilidade econÎmica e anålise de risco
Na microrregiĂŁo de Viçosa - MG, a criação de frango de corte via contratos de integração com a PIF-PAF S/A IndĂșstria e ComĂ©rcio tornou-se fonte adicional de renda para as propriedades rurais de pequeno e mĂ©dio porte. Assim, este trabalho visou verificar a viabilidade de contratos de integração nessa regiĂŁo; especificamente, pretendeu-se elaborar e analisar um projeto de implantação de um aviĂĄrio, determinar a rentabilidade do investimento, mensurar os riscos da atividade sob o ponto de vista do integrado e auxiliar a tomada de decisĂŁo. Para isso, calcularam-se indicadores de viabilidade econĂŽmica do projeto, como Valor Presente LĂquido, Taxa Interna de Retorno e RazĂŁo BenefĂcio/Custo; alĂ©m disso, foi feita uma anĂĄlise de sensibilidade para posterior anĂĄlise de risco. Os resultados apontaram para a viabilidade econĂŽmica do projeto; ademais constatou-se que a sua lucratividade Ă© mais sensĂvel aos componentes da receita do que dos custos, sendo o preço recebido por ave a variĂĄvel de maior sensibilidade. Percebeu-se tambĂ©m que os contratos de integração nĂŁo eliminam totalmente o risco da atividade e que a integradora transfere parte do risco de preços ao produtor.<br>The chicken production in Viçosa area is done by integration agreement with Pif Paf Company and it is an important option for increasing the income of small farmers. The objective of this paper is to check the viability of integration agreements. A project of a plant for chicken production was drawn and observed in order to determine its profitability and risks, with the purpose of helping the decision making. The Net Present Value, Internal Rate of Return, Cost/Benefit Ratio, Risk Sensitivity and Risk Analysis were calculated. The results show that the project is feasible and the profitability is more sensitive to changes in production price than changes in production costs. This study also points out that the integration agreement does not eliminate the risk of the production, in other words, the company transfers part of the price risk to the producers
Statistical learning in domestic chicks is modulated by strain and sex
Statistical learning is a key mechanism for detecting regularities from a variety of sensory inputs. Precocial newborn domestic chicks provide an excellent model for (1) exploring unsupervised forms of statistical learning in a comparative perspective, and (2) elucidating the ecological function of statistical learning using imprinting procedures. Here we investigated the role of the sex of the chicks in modulating the direction of preference (for familiarity or novelty) in a visual statistical learning task already employed with chicks and human infants. Using both automated tracking and direct human coding, we confirmed chicksâ capacity to recognize the presence of a statistically defined structure underlying a continuous stream of shapes. Using a different chicken strain than previous studies, we were also able to highlight sex differences in chicksâ propensity to approach the familiar or novel sequence. This could also explain a previous failure to reveal statistical learning in chicks which sex was however not determined. Our study confirms chicksâ ability to track visual statistics. The pivotal role of sex in determining familiarity or novelty preferences in this species and the interaction with the animalsâ strain highlight the importance to contextualize comparative research within the ecology of each species.This work was supported by funding from the European Research Council (ERC) under the European Unionâs Horizon 2020 research and innovation program (Grant Agreement No. 833504 SPANUMBRA) to GV. The project also received funding from a PRIN 2017 ERC-SH4-A (2017PSRHPZ) to LR and GV. We are grateful to Mirko Tommasi and Momoko Yamabe for their help with testing, and to Camille Frey for drawing the apparatus