Visual working memory (WM) is the ability to hold information in mind for a short time before acting on it. The capacity of WM is strikingly limited. To make the most of this precious resource, humans exhibit a high degree of cognitive flexibility: We can prioritize information that is relevant to behavior, and inhibit unnecessary distractions. This thesis examines some behavioral and neural correlates of flexibility in WM. When information is of particular importance, anticipatory attention can be directed to where it will likely appear. Oscillations in visual cortex, in the 10-Hz range, play an important role in regulating excitability of such prioritized locations. Chapter 4 describes how even spontaneous fluctuations in 10-Hz synchronization (measured by electroencephalography, EEG) before encoding influence WM. Chapters 2 and 3 describe how attention can be directed retrospectively to items even if they are already stored in WM. Chapter 3 discusses how retrospective cues change neural synchronization similarly to anticipatory cues. Behavioral and neural measures additionally indicate that the boosting of an item through retrospective cues does not require prolonged deployment of attention: rather, it may be a transient process. The second half of this thesis additionally examines how items are represented in visual WM. Chapter 5 summarizes a study using pattern analysis of magnetoencephalographic (MEG) and EEG data to decode features of visual templates stored in WM. Decoding appears transiently around the time when potential target stimuli are expected, in line with a flexible reactivation mechanism. Chapter 6 further examines separate cortical networks involved in protecting vs. updating items in WM, and tests whether task relevance changes how well WM contents can be decoded. Finally, Chapter 7 summarizes the thesis and discusses how attentional flexibility can merge WM with a wider range of sources of behavioral control.

O objetivo deste estudo foi investigar os efeitos da autofala na aprendizagem motora. A tarefa utilizada foi o forehand do tênis de campo. Oitenta e quatro universitários foram divididos em cinco grupos experimentais e um controle (n = 14). Dentre os grupos experimentais um deles utilizou-se de quatro dicas para direcionamento da atenção a elementos-chave da rebatida, os demais fizeram uso de apenas uma das quatro dicas (bola, quique, bater, pronto), já o grupo controle recebeu somente instruções gerais fornecidas a todos os participantes. Na fase de aquisição todos os grupos realizaram 180 rebatidas divididas em 60 por dia. Em seguida, eles realizaram um teste de transferência contendo 10 rebatidas com mudança da direção do outro alvo e, após 5 dias, um teste de retenção contendo 10 rebatidas nas mesmas condições da fase de aquisição. A variável dependente foi o acerto ao alvo localizado na quadra adversária. Os resultados mostraram que todos os grupos melhoraram os desempenhos na fase de aquisição, os quais foram mantidos nos testes de transferência e retenção. Entretanto, não foram encontradas diferenças entre os grupos. Concluiu-se que as aprendizagens do forehand com e sem a autofala apresentaram efeitos similares. E, ainda, que a autofala sobre quatro aspectos da tarefa foi similar àquelas com autofala de apenas um aspecto / The aim of this study was to investigate the effects of self-talk on the motor learning. The task was the forehand of the tennis. Eighty-four students were divided into five experimental groups and one control group (n = 14). One of the experimental groups used four cues for directing attention to key elements of forehand. The other groups have made use of only one of the four cues (ball, bounce, hit, ready), and the control group received only general instructions. In the acquisition phase all groups performed 180 trials which were divided into 60 per day. Then they performed a transfer test of 10 trials involving a shift in the target direction and, after 5 days a retention test was run with ten trials in the same conditions of the acquisition phase. The dependent variable was the hit to the target located in the opponent\'s court. The results showed that all groups improved their performances in the acquisition phase, which were kept in the retention and transfer tests. However, no differences were found between groups. It was concluded that the learning of the forehand with and without self-talk showed similar effects. And, that self-talk of four aspects of the task was similar to those with self-talk of only one aspect

Made available in DSpace on 2017-07-10T17:30:27Z (GMT). No. of bitstreams: 1 VILMAR RIGO.pdf: 4959214 bytes, checksum: 25fcdcabb0871431acd340cf107fa1e7 (MD5) Previous issue date: 2014-05-13 / This master's thesis focuses the solid waste´s management in Francisco Beltrão county, starting from the decade of 1970, seeking to raise at first historical facts of how was the evolution in the generation and disposal of solid waste. The study shows how it was carried out and the main points of dumping of waste collected within the city limits, taking these points in the proximity to water resources and the environmental risks offered. It is noteworthy in this regard that the municipal administrations historically not showed a significant concern with environmental issues, since the forms of provisions of the waste collected would affect directly the natural resources, contaminating and compromising the local fauna and flora, and offering health risks of the population, especially with the emergence of vectors that cause diseases and pollution of water resources. In summary, the present study sought to raise information of the evolution in the management of solid waste, aiming to evaluate the participation of the municipal public power and the fulfilment of laws aimed at the National Policy of Solid Waste (PNRS), Federal Law no. 12,305, of august 02, 2010. For that study literature searches, queries to documents and interviews with State Prosecutor, Environmental Institute of Paraná (IAP), former employees of the municipal government of Francisco Beltrão were used, in addition to site visits at various points the municipality. As a result, the management of solid waste in the county presents a very positive development mainly from the year 2001, highlighting this year the construction of the landfill, the implementation of selective collection in 2006, and from 2010 the creation of echo points, the expansion of selective collection in urban and rural area and the development of the Integrated Solid Waste Plan of the municipality. Also points out the deficiencies still exist, and suggests some alternatives to suit them. / A presente dissertação de mestrado aborda a gestão de resíduos sólidos no município de Francisco Beltrão, a partir da década de 1970, buscando levantar primeiramente fatos históricos de como foi à evolução na geração e destinação dos resíduos sólidos. O estudo aponta como era realizada a coleta e os principais pontos de despejo de resíduos coletados no perímetro urbano, tendo estes pontos em comum a proximidade com recursos hídricos e os riscos ambientais oferecidos. Ressalta-se nesse sentido que as administrações municipais historicamente não demonstravam uma preocupação relevante com as questões ambientais, já que as formas de disposição dos resíduos coletados afetavam diretamente os recursos naturais, contaminando e comprometendo a flora e a fauna local, e oferecendo riscos à saúde da população, principalmente com surgimento de vetores causadores de doenças e a poluição dos recursos hídricos. Em resumo, o estudo buscou levantar informações da evolução na gestão dos resíduos sólidos, avaliando a participação do poder público municipal e o cumprimento das legislações decorrentes da Política Nacional de Resíduos Sólidos (PNRS), Lei Federal nº 12.305, de 02 de agosto de 2010. Para o referido estudo foram utilizadas pesquisas bibliográficas, consultas a documentos e entrevistas com Promotoria Pública Estadual, Instituto Ambiental do Paraná (IAP), Secretaria Municipal de Meio Ambiente, antigos funcionários da prefeitura municipal de Francisco Beltrão, além de visitas in loco em diversos pontos do município. Como resultado, a gestão dos resíduos sólidos do município apresenta uma evolução muito positiva principalmente a partir do ano de 2001, ressaltando neste ano de forma relevante a construção do aterro sanitário, a implantação da coleta seletiva em 2006 e a partir do ano de 2010 a criação de eco pontos, a ampliação da coleta seletiva no perímetro urbano e rural e a elaboração do Plano Integrado de Resíduos Sólidos do município. Também aponta as irregularidades que ainda existem e sugere algumas alternativas para adequação das mesmas.

Tabagistas atendem seletivamente a estímulos ambientais relacionados ao cigarro, um processo cognitivo implícito denominado viés na atenção (VA). Contudo, não está claro se o VA persiste em ex-fumantes. Por isso, avaliou-se a influência do tempo de abstinência no VA em 62 ex-fumantes (de 50±11 anos) através de uma tarefa de atenção visual em computador. Independente do tempo de abstinência, os participantes evitaram as pistas associadas ao tabaco. Esta esquiva foi mais pronunciada em tempos de exposição maiores. Os ex-fumantes também atribuíram pouca valência emocional às imagens associadas ao cigarro e reportaram índices baixos de fissura antes e após a tarefa. O VA negativo e a menor valência emocional destas pistas podem constituir um processo de modulação da atenção típico da abstinência prolongada, no qual estratégias cognitivas são empregadas para manter este estado. Os resultados obtidos contribuem para a compreensão da cognição implícita na adição e sua importância no tratamento e prevenção do tabagismo. / Smokers selectively attend to smoking-related cues, an implicit cognitive process called attentional bias (AB). However, it is unclear whether former smokers present AB. Therefore, we evaluated the influence of abstinence time in VA in 62 exsmokers (50 ± 11 years-old) through a visual probe task. Participants avoided smoking cues despite of abstinence time. This avoidance was more pronounced in longer stimuli exposition. Former smokers also attributed little emotional valence to smoking cues and reported low craving rates both before and after the task. The negative AB and low emotional valence of smoking cues might constitute a process of attentional modulation typical of longer abstinence, in which cognitive strategies are employed to maintain this state. The results contribute to the understanding of implicit cognition in addiction and its importance to smoking treatment and prevention.

O sistema de gerenciamento dos resíduos sólidos domiciliares tem início na geração dos mesmos, em que os materiais são avaliados pelo usuário como não tendo mais valor ou utilidade. Após isso, tem-se o acondicionamento e a coleta. Esta coleta pode ser regular, especial ou seletiva. Na coleta regular e na especial, que abrange os resíduos não retirados pela coleta anterior, os resíduos são encaminhados diretamente para a disposição final. Na coleta seletiva, que pode ser executada porta a porta ou através de PEV\'s (Postos de Entrega Voluntária), os materiais recicláveis são encaminhados para centrais de revalorização. Esta etapa faz parte da logística reversa, que é uma importante ferramenta para o gerenciamento destes resíduos, uma vez que tem como objetivo a gestão integral do fluxo de retorno de embalagens e produtos pós-consumo, compreendendo todas as atividades enfocadas na redução, reutilização e reciclagem. Dentro deste contexto, para o objetivo deste trabalho ser alcançado, foi analisado de que maneira a coleta seletiva é executada em algumas cidades brasileiras de acordo com o CEMPRE (2002). A conclusão obtida foi que, na maioria destas cidades, este sistema reverso é executado por cooperativas, pelas próprias prefeituras ou por \"catadores\" autônomos e que as empresas coletoras de resíduos são responsáveis pela coleta seletiva em 33% das cidades pesquisadas. / The manager system of residential solid waste begins on its discharge in the time that these materials are available as without value or utility by users. After that, it has been the packaging and the collection. This colleted can be regular, special or selective. Regular and special collected, which included residuals not removed by previous collected, the residuals are forwarded directly to final place. In the selective collection that can be made door by door or through drop-off centers, recycle materials are forwarded to revaluation centrals. This step is part of reverse logistic that it is an important tool for management of residuals once it has as objective an integral management of return flow of packings and consumption products and it is included all activities of reduction, reusing and recycling. Inside of this context, for reaching the objective of this research, it was analyzed the manner that selective collection it is carried out in some Brazilian cities according to CEMPRE (2002). The conclusion obtained it was that in the most of these cities this reverse system is carried out by cooperatives, by own city halls or by autonomous collectors. Also, it was observed that collector companies of residuals are responsible by selective collection in 33% of cities analyzed.

Doctor of Philosophy / Department of Psychological Sciences / Lester C. Loschky / Visual resolution (i.e., blur or clarity) is a natural aspect of vision. It has been used by film makers to direct their audience’s attention by focusing the depth of field such that the critical region in a scene is uniquely clear and the surrounding is blurred. Resolution contrast can focus attention towards unique clarity, as supported by previous eye tracking and visual search research (Enns & MacDonald, 2013; Kosara, Miksch, Hauser, Schrammel, Giller, & Tscheligi, 2002; & McConkie, 2002; Peterson, 2016; Smith & Tadmor, 2012). However, little is known about how unique blur is involved in guiding attention (e.g., capture, repel, or be ignored). Peterson (2016) provided reaction time (RT) evidence that blur is ignored by selective attention when resolution is not task-relevant. Perhaps visual resolution is a search asymmetry where unique clarity can be used to guide selective attention during search, but unique blur cannot guide attention. Yet, perhaps the RT evidence was not sensitive enough with Peterson’s (2016) methodology to observe unique blur capturing or repelling attention. Eye movements (e.g., letter first fixated) may be more sensitive than RT as it measures blur and clarity’s influence on guiding attention earlier in a trial. The current study conducted three experiments that investigated: a) how visual resolution guides attention when it is task-irrelevant (Exp. 1), b) whether visual resolution is a search asymmetry, by manipulating resolution’s task-relevance (Use Blur, Use Clarity, Do Not Use Unique Blur or Clarity, & No Instructions) (Exp. 2), and c) whether blur and/or clarity are processed preattentively or require attention (Exp. 3). Experiments 1 and 2 manipulated blur and clarity (Exp. 1 Resolution = Task-irrelevant & Exp. 2 Resolution = Task-relevant), during a rotated L and T visual search measuring RT and eye movements. Experiment 1 found with the more sensitive eye movement measures that unique clarity strongly captured attention while unique blur weakly repelled attention towards nearby clarity (or clarity, especially that close to blur, captured attention). Experiment 2 found evidence that visual resolution is not a search asymmetry because the influence of resolution on selective attention was contingent upon its task-relevance, which theoretically supports the presence of a reconfigurable resolution feature detector. Experiment 3 used a feature search for either blur or clarity (i.e., resolution was task-relevant) and compared RT x Set Size search slopes. Both blurred and clear target present RT x Set Size search slopes were ~ 1 msec/item. The results strongly supported that blur and clarity are both processed preattentively, and provided additional evidence that resolution is not a search asymmetry. Overall, the current studies shed light on how visual resolution is processed and guides selective attention. The results revealed that visual resolution is processed preattentively and has a dynamic relationship with selective attention. Predicting how resolution will guide attention requires knowledge of whether resolution is task relevant or irrelevant. By increasing our understanding of how resolution contrast guides attention, we can potentially apply this knowledge to direct viewers’ attention more efficient using computer screens and heads-up displays.

O presente trabalho visou a construção e avaliação de eletrodos de membrana sólida cristalina seletivos a cobre e prata. Obteve-se o sulfeto de prata, material eletroativo usado na preparação de membranas seletivas a íons Ag+, por precipitação com gás sulfídrico em meio ácido. Eletrodos com membranas de 1,0 e 0,50 mm de espessura apresentaram respectivamente limites nernstianos de 10-4 e 10-5 Mol.L-1 e precisão de ± 0,1 e 1 mV nas leituras de potencial. Os sulfetos de cobre e prata, usados na preparação de membranas seletivas para determinação de cobre, foram obtidos por precipitação simultânea com gás sulfídrico, tioacetamida em meio ácido e tiouréia em meio amoniacal. Difratogramas de Raios X revelaram que o material obtido com tiouréia corresponde ao sulfeto ternário, Cu2S.3Ag2S ou Ag1,55Cu0,45S, responsável pela resposta seletiva do sensor em soluções de Cu2+. O eletrodo construído a partir deste sulfeto, onde o cobre aparece no estado monovalente, apresentou limite nernstiano da ordem de10-7Mol.L-1, fornecendo resultados satisfatórios na determinação deste metal em amostras de aguardente e álcool. Cálculos termodinâmicos mostraram que quando membrana é constituída de CuS, um contacto elétrico efetuado através de cobre ou prata é instável, uma vez que ocorre a formação de Cu2S. Os resultados experimentais conduziram a um novo modelo para explicar o mecanismo de resposta do eletrodo, o qual se baseia na reação: Cu2S (memb) + Cu2+ (sol) ↔ CuS (memb) + 2 Cu + (sol). A atividade de Cu+ na interface eletrodo / solução é controlada pela atividade de Cu2+ nas soluções de medida, de modo que o sensor funciona como um eletrodo de Cu2S/CuS em contacto com o sistema Cu2+/Cu+. / Present work deals with the assembling and testing of solid membrane electrodes for copper and silver. The silver sulphide used to prepare the membrane selective to Ag+ was precipitated with hydrogen sulphide in acidic medium. Electrodes 1,0 and 0,50 mm thick present Nernstian limits of 10-4 and 10-5 Mol.L-1 order with a ± 0,1 and 1 mV respectively. A mixture of silver sulphide and copper sulphides were used for the copper (II) selective electrode. This solid was prepared from Cu2+ and Ag+ in the same solution with hydrogen sulphide or thioacetamide both in acid medium and with thiourea in ammoniacal medium. X-Ray diffractograms shows that the solid prepared from thiourea solutions presents significant contribution of jalpaite Ag1,55Cu0, 45S (in fact Cu2S.3Ag2S). An important finding was the presence of copper (I) in the matrix and this has been also found to the responsible for the higher performance of this electrode with a limiting response to 10-7 Mol.L-1 copper (II). In fact thermodinamic calculation has show instability of a contact of Ag or Cu with CuS solid, as Cu2S must be formed in any case. On this basis, the theory of the electrode is based in the following reaction which takes place on the electrode surface: Cu2S (memb) +CU2+ (sol) ↔ CuS (memb) + 2 Cu+(aq) K = 10-13 M. On this basis the Cu+ activity at the electrode / solution interface is controled by the activity of Cu2+ of the solution and the Cu2+/ Cu+ system in contact with the solid matrix is defined.

Este trabalho enfocou o levantamento de informações químicas e mineralógicas de detalhe em amostras de depósitos alcalinos e alcalino carbonatíticos brasileiros contento terras raras, de modo a fornecer subsídios para o desenvolvimento de processos de aproveitamento. Estes depósitos apresentam elevados volumes de recursos, baixos teores de elementos de terras raras (essencialmente terras raras leves) e elevada complexidade mineralógica. As amostras estudadas são provenientes de depósitos lateríticos, com teor total de óxidos de terras raras entre 1,27 e 6,45%, sendo a monazita o principal mineral portador desses elementos, exceto em uma das amostras, onde é predominante a bastnaesita; como minerais traços estão presentes cerianita, xenotima e um fosfato de escândio. Os minerais de terras raras tendem a concentrar-se em direção às frações granulométricas mais finas, mostram d50 de 15 µm nas frações acima de 0,008 mm e chegam a valores inferiores a 0,1 µm abaixo da mesma. Esses minerais ocorrem preferencialmente em íntimas associações com a ganga, sendo que valores superiores a 60% de liberação (em área) são observados apenas nas frações menores que 0,020 mm. O potencial de concentração desses minerais foi avaliado por separações físicas e extração hidrometalúrgica. Separações físicas em líquidos densos e magnéticas não possibilitaram a obtenção de produtos enriquecidos em terras raras. O resultado mais promissor refere-se à possibilidade de remoção de um produto contaminante magnético nas frações retidas em 0,020 mm e que responde por 30% do total de Fe2O3 contido nas amostras (em média), sem perdas significativas das terras raras. A condição experimental otimizada para a dissolução seletiva dos minerais de terras raras em meio ácido foi estabelecida a partir de um planejamento experimental baseado em princípios estatísticos. Para o material cominuído abaixo de 0,30 mm, a solubilização dos óxidos de terra raras é de 77%, considerando-se ácido sulfúrico concentrado, reduzida porcentagem de sólidos, temperatura ambiente e tempo de 4 horas. Maiores níveis de solubilização das terras raras podem ser alcançados, mas juntamente com elevação da solubilização da ganga. / This work focused on the acquisition of chemical and mineralogical detailed information in samples from Brazilian alkaline and alkaline-carbonatitic deposits containing rare earths, in order to provide subsidies for process development. These deposits present high volumes of resources, low contents of rare earth elements (essentially light rare earths) and high mineralogical complexity. The studied samples are lateritic materials, with a total content of rare earth oxides between 1.27 and 6.45%, being monazite the main rare earth bearing mineral, except in one of the samples, where bastnaesite is predominant; cerianite, xenotime and a scandium-phosphate occur as trace. Rare earth minerals tend to enrich toward the finest sieve fractions with an medium grain size of 15 µm in the fractions greater than 0.008 mm and decreasing below 0.1 µm in finer fractions. These minerals occur preferentially in intimate associations with the gangue; liberation greater than 60% (in area) are observed under 0.020 mm fractions. The concentration potential of these minerals was evaluated through physical separation and hydrometallurgical extraction. Physical separations (heavy liquid and magnetic) did not succeed in obtaining products enriched in rare earths. The most promising result were the possibility of removing magnetic phases above 0.020 mm (responsible for 30%, on average, of the total Fe2O3 contained in the samples) without significant losses of rare earths. The rare earths acid leaching protocols and conditions were established by statistical experimental design. For samples comminuted below 0.30 mm, the best rare earths solubilization (77%) and with minimum gangue leaching was obtained in concentrate sulfuric acid, low solids concentration, environmental temperature and four hours of reaction. Higher levels of rare earths solubilization can be achieved, however accompanied by higher gangue solubilization.

Ce travail est consacré à l'épitaxie en phase gazeuse d'organométallique de nanostructures de nitrures en forme de fil et de pyramide, pour lesquelles nous cherchons à comprendre les mécanismes de croissance mis en jeu. Une étude paramétrique complète est présentée pour optimiser et mieux appréhender la croissance de nanofils GaN auto-assemblés non-catalysés. Nous démontrons notamment que l'injection de silane est un paramètre-clé pour la croissance des nanofils grâce à la formation d'une couche SiNx de passivation sur les facettes latérales qui joue le rôle d'un masque favorisant ainsi la croissance verticale. Un nouveau procédé de croissance de nanofils sans silane est aussi proposé dans ce travail en utilisant de très faibles flux de précurseurs qui favorise la formation de facettes verticales. De tels nanofils présentent d'excellentes propriétés structurales et optiques grâce à l'absence de silicium. Par ailleurs, nous montrons que la polarité joue un rôle crucial sur la croissance des nanostructures de GaN puisque la forme des nanostructures peut être simplement déterminée par l'orientation de la polarité: une polarité N résulte en fils alors qu'une polarité Ga en pyramides. Par conséquent, la forme fil/pyramide des nanostructures peut être directement choisie en contrôlant la polarité sur des substrats de saphir ou de GaN. Nous avons justement exploité cette méthode pour obtenir des réseaux ordonnés de fils et de pyramides de GaN en utilisant la croissance sélective à travers un masque nanostructuré par lithographie. De telles nanostructures ont été utilisées pour la croissance d'hétérostructures InGaN/GaN pour obtenir soit des puits quantiques non-polaires sur les flans des nanofils, soit des boîtes quantiques d'InGaN aux sommets des pyramides. / This work reports the metal-organic vapour phase epitaxy of III-Nitride wire- or pyramid-shaped nanostructures and focuses on the growth mechanisms related to these two types of GaN nanostrcutures. A complete parametric study is presented in order to optimize and to understand the catalyst-free self-assembled GaN nanowire growths. We demonstrate that the silane flux injection is a key-parameter for nanowire growth thanks to the formation of SiNx passivation layer along the sidewall facets that acts as a mask favoring the vertical growth. A novel silane-free nanowire growth is also proposed in this work using ultra-low precursor flux that favors the formation of vertical facets. Such nanowires exhibit excellent structural and optical properties due to the absence of silicon. In addition, the polarity is found to play a key-role for GaN nanostructure growth, since the nanostructure shape can be basically determined by the polarity orientation: N-polar nanostructure results in wire, whereas Ga-polar in pyramid. Consequently, the shape wire/pyramid of nanostructure can be chosen depending on the polarity control on sapphire or GaN substrates. This method is applied to get ordered arrays of GaN wires and pyramids using selective area growth on patterned mask. Such nanostructures can be used as template for InGaN/GaN heterostructure growth to get either non-polar multi-quantum wells along the wire sidewalls or InGaN quantum dots at the pyramid apex.

This research aims to fill a research gap by examining WeChat to explore whether changes of social context would exert any influence on the information disclosure of social networking site (SNS) users. Selective Exposure Theory and Uses and Gratification Theory were used as the theoretical foundation for this study. Four-hundred Chinese college students in China and the U.S. who have a WeChat App and have logged in to use it within the last 30 days from the day administered were asked to participate in a survey about their motivations and consequences when using WeChat. Results from MANOVA showed that the motivations and consequences of female participants’ self-disclosure were significantly higher than were male participants on WeChat. Moreover, the social context of Chinese students studying in the U.S. is perceived to be more individualized than the traditionally collective context that is perceived by Chinese students studying in China.