No description available.

This paper reports a series of experiments designed to compare memory for multiple kinds of source information in young and older adults. The older adults in these studies were classified as having well or poorly functioning frontal lobes. In EXPERIMENTS 1-3, three different sources that provided independent cues to item information were examined using a repeated-measures design. In particular, participants' memory for voice source information, spatial source information, and temporal source information was tested in separate blocks. The results indicated that the performance of both young and older adults depended upon the type of source tested: Voice source memory was superior to spatial source and temporal source memory, which did not differ. There was also an age effect that was mediated by frontal functioning. Only the low frontal older adults showed impairments in source memory. High frontal older adults were equivalent to young. In EXPERIMENT 4, sources that provided redundant cues to item information were investigated. Voice sources and spatial sources were perfectly matched during encoding such that Voice A always came from Location 1 and Voice B always came from Location 2. When sources provided redundant information in this manner, young and high frontal older adults improved their spatial source memory by making use of redundant voice information, whereas the low frontal older adults not only performed more poorly than both young and high frontal older adults, but were unable to benefit from the redundancy. No differences in item memory were found. The findings were interpreted in terms of the executive and working memory functions involved in the integration of various contextual elements of an experience with its content.

Implementation intentions have been shown to improve prospective memory performance among a variety of populations. In two studies, the effectiveness of implementation intentions was examined among young and older adults. In Experiment 1 64 young adults were placed into one of four instructional conditions (Read-Only, Imagery, Implementation Intention, Combined) before completing a laboratory-based prospective memory task. Results reveal that prospective memory performance improves under each of the three experimental conditions, but that there is no additional benefit of combining imagery with implementation intentions. In a novel finding, imagery alone produced improvements comparable to implementation intentions. Experiment 2 investigated the effect of implementation intentions among 32 older adults, who were characterized as possessing high- or low-frontal function based on neuropsychological test performance. Implementation intentions improved prospective memory among both groups, regardless of frontal function. The results of these studies suggest that implementation intentions can improve prospective memory among both young and older adults. Importantly, these findings reveal that imagery alone may be an effective means of improving prospective memory. Additionally, that implementation intentions improved prospective memory among older adults, regardless of frontal function, raises important questions about potential mechanisms underlying the effectiveness of implementation intentions.

It is well established that older adults show a deficit in episodic memory. The associative deficit hypothesis (ADH) (Naveh-Benjamin, 2000) suggests that an age-related reduced ability to create links between units of information is a major contributor to the episodic deficit. It has been a robust finding that older adults show a disproportionate decline in associative memory relative to item memory when compared to young adults. Previous researchers have investigated the role of the frontal lobes (FL) by studying the effect of reduced attentional resources in the associative deficit. However, they have not found that divided attention in young adults produces the disproportionate associative decline seen in aging and it is thought that some cognitive process other than the allocation of attentional resources may contribute to the associative deficit. The present study intended to use a divided attention (DA) task that also engages medial temporal brain regions (MTL) in order to tax additional parts of the network involved in creating associations and provide indirect support for the role of the MTL in the associative deficit. However, the associative memory deficit in older adults was not replicated due to unique poor associative memory performance of some young adults in the study. Analyses excluding these participants show support for the role of the MTL in the associative deficit. However, the young poor performers may provide support for the role of FL function in the associative deficit and show that poor associative memory may not be limited to the older adult cohort.

Previous research has suggested that viewing of another’s averted eye gaze causes automatic orienting of attention and eye movements in observers due to the importance of eye gaze for effective social interaction. Other types of visual cues with no social or biological relevance, such as arrows, are claimed not to produce such a direct effect on orienting behaviour. The finding that processing of eye gaze is reduced in individuals with Autistic Spectrum Disorders as well as following damage to the orbitofrontal cortex of the brain, suggests that gaze processing is indeed critical for effective social behaviour and therefore eye gaze may constitute a “special” directional cue. This thesis tested these ideas by examining the influence of socio-biological (eye gaze and finger pointing) and non-social cues (arrows and words) on eye movement responses in both healthy control participants and those with damage to the frontal lobes of the brain. It further investigated the relationship between orienting to gaze and arrow cues and autistic traits in a healthy population. Important differences between the effects of socio-biological and non-social cues were found on saccadic eye movements. Although in the pro-saccade tasks, arrow cues caused a similar facilitation of responses in the cued direction as eye gaze and pointing cues, in the anti-saccade tasks (in which participants have to respond away from the location of a peripheral onset), arrows had a greatly reduced effect on oculomotor programming relative to the biologically relevant cues. Importantly, although the socio-biological cues continued to influence saccadic responses, the facilitation was in the opposite direction to the cues. This finding suggests that the cues were being processed within the same "anti-response" task set (i.e. "go opposite") as the target stimulus. Word cues had almost no effects on saccadic orienting in either pro- or anti-saccade tasks. Schematicised eye gaze cues had a smaller magnitude effect than photographic gaze cues suggesting that ecological validity ("biological-ness") is an important factor in influencing oculomotor responses to social cues. No relationship was found between autistic traits and orienting to gaze or arrow cues in a large sample of males. However, findings from the neurological patients point to a possible double-dissociation between the neural mechanisms subserving processing of socio-biological and non-social cues, with the former reliant on the orbitofrontal cortex, and the latter on lateral frontal cortex. Taken together, these results suggest that biologically relevant cues have privileged access to the oculomotor system. The findings are interpreted in terms of a neurocognitive model of saccadic orienting to socio-biological and non-social cues, and an extension to an existing model of saccade generation is proposed. Finally, limitations of the research, its wider impact and directions for future work are discussed.

Magíster en Ciencias, Mención Geología / La Cordillera Frontal, alrededor de los 28°45 S, representa un muy buen ejemplo para explorar los procesos y factores que determinaron la evolución tectónica de los Andes Centrales durante el cenozoico, basada en el estudio de las secuencia de sedimentos detríticos continentales presentes en la zona y de las superficies erosivas que definen discordancias entre distintas secuencias. En este trabajo se analizan los registros geomorfológicos y estratigráficos con el objetivo de conocer los tiempos y propagación de deformación que controlaron la construcción de los Andes en esta latitud durante el Cenozoico, así como de la erosión como respuesta. Las secuencias de sedimentos detríticos continentales presentes en la zona están rodeadas por cuatro sistemas morfoestructurales limitados por fallas inversas de alto ángulo. Los sistemas norte y oeste fueron alzados durante el Eoceno. Dentro de las fallas que se reconocen se destaca la Falla Valeriano, de vergencia hacia el este, cuya última actividad está registrada alrededor de los 44 Ma. Luego del alzamiento de este sistema una extensa superficie de pedimentación se desarrolló hasta los 21 Ma, asociado a un nivel de base que drenaba hacia el Este. Relictos de esta superficie se preservan y están descubiertas en los sistemas morfoestructurales que se extienden hacia oeste y norte. Hacia el este y sur esta superficie se encuentra cubierta por las secuencias sedimentaras o están degradadas ante la erosión estimulada por el alzamiento mioceno de los sistemas morfoestructurales orientales. El alzamiento durante el mioceno fue acomodado por fallas del Sistema de Fallas La Coipa-El Potro, con vergencias tanto al este como al oeste, cuya actividad entre los 19 y 13 Ma acomodó el alzamiento de los bloques este y sur, interrumpió los procesos de pedimentación, determinó la formación de un depocentro de intramontañoso, y forzó la acumulación de las secuencias detríticas continentales, en un ambiente aluvial y fluvial trenzado, con una mayor contribución del bloque occidental y un menor aporte del bloque oriental. Luego de los 13 Ma, el alzamiento del bloque oriental habría determinado la captura de las precipitaciones de esta zona en la ladera occidental de los Andes, aumentando el área y el relieve de las cuencas, lo que habría determinado el aumento del poder incisivo de los ríos. Esta reconfiguración hidrológica determinó el retrabajo de las Gravas de Cerro del Burro y el desarrollo de profundos cañones, como los que hoy dominan el paisaje. La relación entre incisión y agradación en los actuales canales, que se infiere del análisis morfométrico de los thalweg, estaría fuertemente controlada por la herencia de la geomorfología que fue construida previa a la reconfiguración, mostrando que los canales que se extienden en el área capturada a los 13 Ma, presentan menor madurez en términos geomorfológicos, constituyendo formas transitorias en desequilibrio y aún no ajustadas a los niveles de base regionales. / Este trabajo ha sido financiado por el Proyecto Fondecyt N° 11121529, a cargo del Dr. Germán Aguilar Martorell

<p>U ovom radu je analiziran uticaj Vi&scaron;efrontalne metodologije na povećanje efikasnosti nastavnog procesa na tehničko-tehnolo&scaron;ki orijentisanim fakultetima. Sprovedeni eksperiment je pokazao da ova metodologija pozitivno utiče na ključne parameter kroz koje je moguće definisati efikasnost tako složenog procesa kao &scaron;to je nastava. Poseban akcenat je stavljen na faktor unutra&scaron;nje motivacije, za koji je takođe obrazložen eksperimentom uočen pozitivan uticaj koji ova metoda na njega ostvaruje. U radu su date preporuke za primenu ove metode u visokom &scaron;kolstvu. Uočene su potencijalne pote&scaron;koće u njenoj implementaciji, na osnovu čega su date preoruke za njeno unapređenje i adaptaciju za specifične uslove visokog &scaron;kolstva na tehničko-tehnolo&scaron;kim fakultetima.</p> / <p>In this disertation, the impact of Multi-frontal methodology on increasing the efficiency of the teaching process is analyzed in technically and technologically oriented faculties. The conducted experiments showed that this methodology positively influenced key parameters through which it is possible to define the efficiency of such a complicated process as teaching is. Special emphasis is placed on the inner motivation factor. It was noticed through experimentally conducted analysis that this methodology positively influenced this factor. The dissertation gives recommendations for the application of these methods in higher education. Potential difficulties in its implementation were observed, and recommendations were given for its improvement and adaptation to specific conditions of higher education in technical and technological universities.</p>

The aim of this thesis was to understand the function of the frontal lobes during different types of decisions thusfar mostly neglected in cognitive neuroscience. Namely, I sought to understand how decisions are made when comparisons are not about a simple set of concrete options presented, but rather require a comparison with one specific encounter and a sense of the value of the current environment <b>(Chapter 2-3)</b>. Additionally, I wanted to understand how decisions between concrete options can be contextualized by the current environment to allow considerations about changing environmental constraints to factor into the decision making process <b>(Chapter 4-5)</b>. At last, I wanted to test how the potential for future behaviours within an environment has an effect on peoples decisions <b>(Chapter 6)</b>. In other words, how do people construct prospective value when it requires a sense of own future behaviours? All this work was informed by concepts and models originating from optimal foraging theory, which seeks to understand animal behaviours using computational models for different ecological types of choices. Thus, this thesis offers a perspective on the neural mechanisms underlying human decision making capacities that relates them to common problems faced by animals and presumably humans in ecological environments <b>(Chapter 1 and 7)</b>. As optimal foraging theory assumes that solving these problems efficiently is highly relevant for survival, it is possible that neural structures evolved in ways to particularly accommodate for the solution of those problems. Therefore, different prefrontal structures might be dedicated to unique ways of solving ecological kinds of decision problems. My thesis as a whole gives some evidence for such a perspective, as dACC and vmPFC were repeatedly identified as constituting unique systems for evaluation according to different reference frames. Their competition within a wider network of areas appeared to ultimately drive decisions under changing contexts. In the future, a better understanding of those changing interactions between these prefrontal areas which generate more complex and adaptive behaviours, will be crucial for understanding more natural choice behaviours. For this temporally resolved neural measurements as well as causal interference will be essential.

Title: Biomechanical reflection of the cervicocranial part during frontal impact Objectives: The aim of the work was to analyze in which parameters differs ATD from human participant during frontal impact. Characterize the head movement, compare maximal post impact head speed between ATD and human volunteers and defereneces between volunteer with eye control and without. Methods: Measuring was done with 8 volunteers and ATD (Manikin, 50th percentile man). For each volunteer were done two measurements, first without eye control and second with eye control. ATD was measured twice. It was recorded by Qualisys system, specifically by three optical cameras, on crash simulator. Results were processed in Qualisys Track Manager. There were tracked three markers, two on the body - forehead, shoulder and one on the sledge. Results: Results showed that speed of the head depends on eye control. Volunteer without eye control had higher post impact speed of head (4,94 m/s) than ATD (3,67 m/s) and volunteer with eye contact (3,19 m/s). Quite the same result was observed in change of distance between head and sledge after impact. There was higher value for volunteer without eye contact than for ATD. Keywords: Whiplash, frontal impact, Qualisys, crash simulator, cervicocranial part

[pt] O Método dos Elementos Discretos (DEM) com base em esferas pode fornecer aproximações para diversos fenômenos físicos complexos, tanto em escala micro quanto macro. Normalmente uma simulação DEM começa com um arranjo de partículas esféricas no interior de um determinado recipiente. Para domínios gerais a criação deste pacote de esferas pode ser complexo e demorado, especialmente se ele deve respeitar requisitos de precisão e de estabilidade da simulação. O objetivo deste trabalho é estender uma solução de empacotamento de discos 2D para gerar conjuntos aleatórios compostos por partículas esféricas não sobrepostas. O algoritmo construtivo proposto utiliza a técnica de frente de avanço, onde as esferas são inseridas uma a uma no pacote, de acordo com uma estratégia gulosa baseada nas partículas previamente inseridas. A técnica de frente de avanço requer a existência de um conjunto inicial de esferas que definem a fronteira do recipiente. Outra extensão importante proposta aqui é uma generalização do algoritmo para lidar com objetos arbitrários definidos por uma malha triangular qualquer. Este trabalho apresenta também alguns resultados que permitem algumas conclusões e sugestões de trabalhos futuros. / [en] The Discrete Element Method (DEM) based on spheres can provide acceptable approximations to many complex physical phenomena both in micro and macro scale. Normally a DEM simulation starts with an arrangement of spherical particles pack inside a given container. For general domains the creation of the sphere pack may be complex and time consuming, especially if the pack must comply with accuracy and stability requirements of the simulation. The objective of this work is to extend a 2D disk packing solution to generate random assemblies composed by non-overlapping spherical particles. The constructive algorithm, presented here, uses the advancing front strategy where spheres are inserted one-by-one in the pack, according to a greed strategy based on the previously inserted particles. Advance front strategy requires the existence of an initial set of spheres that defines the boundary of the pack region. Another important extension presented here is the generalization of algorithm to deal with arbitrary objects defined by a triangular boundary mesh. This work presents also some results that allow for some conclusions and suggestions of further work.