The Effects of Aging on Orientation Discrimination

Visual perception relies on low-level encoding of local orientation. Recent studies show an age-dependent impairment in orientation discrimination of stimuli embedded in external noise, suggesting that encoding of orientation is inefficient in older adults. In the present study we ask whether aging also reduces decoding, i.e., selecting the neural representations of target orientation while discarding those conflicting with it. We compared younger and older participants capability (mean age 24 and 68 years respectively) in discriminating whether the orientation of a Gabor target was left or right from the vertical. We measured (d0), an index of discrimination sensitivity, for orientation offset ranging from 1 to 12. In the isolated target condition, d0 was reduced by aging and, in the older group, did not increase with orientation offset, thus resulting in a larger group difference at large than small orientation offsets from the vertical. Moreover, oriented elements in the background impaired more discrimination in the older group. However, distractors reduced more d0 when target-background orientation offset was large than when target and flanker had similar orientation, indicating that the effect of the background was not local, i.e., due to target inhibition by similarly oriented flankers. Altogether, these results indicate that aging reduces the efficiency in discarding the response to orientations differing from the target. Our results suggest that neural decision-making mechanisms, involving not only signal enhancement but also non-signal inhibition, become inefficient with age. This suggestion is consistent with the neurophysiological evidence of inefficient visual cortical inhibition in aging

Town of Casco Maine Conservation Ordinance

Ordinance Cover: Conservatio

The Fluvial Forests as Indicators of the Flow and Permanence of Water

We evaluated the influence of the horizontal flows of the Paraná River on the composition and distribution of the floodplain landscape and we defined the ecohydrologicalsignature of some species-index in the low Paraná River section, (27° 38? 04? S and 58° 50? 46? W). During the drought phase, the structure of the vegetation were characterizad using a Cottam & Curtis method. The trees were positioned in the topographic gradients during the flood phase, taking as reference the river water sheet in the nearest hydrometric gauge. To obtain the pulse attributes in different positions of the geomorphological gradient, PULSO software was used considering the daily water levels at Corrientes city between 1985 and 2015. Two main types of flooded forests were identified: pionner forest, dominated by one or two species (Salix humboldtiana, Tessaria integrifolia) in recent bars and islands, and pluri-specific flooded forests (Albizia inundata, Cecropia pachystachya, Croton urucurana, Inga uruguensis, Ocotea diospyrifolia, Nectandra angustifolia and Peltophorum dubium) occupying bars of the highest islands, with shorter flood phases, with trees are distributed in 2-3 strata in a closed canopy. Pulses were more frequent in pioneer forests than in multispecific forests. The ecohydrological signature allows the optimum condition and distribution limits of each species to be established. It is a tool to know the adjustment of biotic elements (populations) to the river variability regime. The procedure usedcan be used to anticipate the possible reorganization of the river plain landscape as a result of flow variations predicted by climate change models.Fil: Zambiasio, Violeta Amancay. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Neiff, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Afiliación intelectual y escritura en la universidad : un estudio de caso sobre la perspectiva de los docentes

El presente trabajo constituye un ejercicio de aproximación a la perspectiva del profesorado frente a los problemas intelectuales y discursivos de los estudiantes universitarios. Los datos que se analizan fueron obtenidos mediante la administración de una encuesta y la realización de entrevistas a docentes de tres áreas de formación (Ciencias Sociales, Ciencias Veterinarias e Ingeniería). El trabajo de campo se realizó en la Universidad Nacional del Centro de la Provincia de Buenos Aires, Argentina. En la exposición de resultados se identifican preconcepciones y prácticas docentes con el fin de evaluar su posible gravitación en los procesos de incorporación a la cultura universitaria.This paper is an exercise of approximation to the perspective of teachers facing the intellectual and discursive problems of university students. The analysed data was obtained through a survey and interviews to professors of three different areas of education (Social Sciences, Veterinary Sciences and Engineering). Fieldwork was done in the Universidad Nacional del Centro de la Provincia de Buenos Aires, Argentina. In the presentation of results, preconceptions and teaching practices were identified to assess their potential weight in the incorporation to the university culture.Ce travail constitue un exercice por s'approcher à l'étude des perspectives qu'ont les professeurs sur les problèmes intellectuels et discursifs des étudiants universitaires. Les données de basse ont été obtenues à partir d'une enquête spécifique et des entretiens aux enseignants de trois domaines de formation (Sciences Sociales, Sciences Vétérinaires et Ingénierie). Le travail fut réalisé à l' Universidad Nacional del Centro de la Provincia de Buenos Aires, Argentine. Dans l'exposé des résultats, on identifie les préconceptions et les pratiques d'enseignement avec l'objectif d'évaluer ses effets possibles sur les processus d'incorporation à la culture universitaire