Neural network mechanisms of working memory interference

[eng] Our ability to memorize is at the core of our cognitive abilities. How could we effectively make decisions without considering memories of previous experiences? Broadly, our memories can be divided in two categories: long-term and short-term memories. Sometimes, short-term memory is also called working memory and throughout this thesis I will use both terms interchangeably. As the names suggest, long-term memory is the memory you use when you remember concepts for a long time, such as your name or age, while short-term memory is the system you engage while choosing between different wines at the liquor store. As your attention jumps from one bottle to another, you need to hold in memory characteristics of previous ones to pick your favourite. By the time you pick your favourite bottle, you might remember the prices or grape types of the other bottles, but you are likely to forget all of those details an hour later at home, opening the wine in front of your guests. The overall goal of this thesis is to study the neural mechanisms that underlie working memory interference, as reflected in quantitative, systematic behavioral biases. Ultimately, the goal of each chapter, even when focused exclusively on behavioral experiments, is to nail down plausible neural mechanisms that can produce specific behavioral and neurophysiological findings. To this end, we use the bump-attractor model as our working hypothesis, with which we often contrast the synaptic working memory model. The work performed during this thesis is described here in 3 main chapters, encapsulation 5 broad goals: In Chapter 4.1, we aim at testing behavioral predictions of a bump-attractor (1) network when used to store multiple items. Moreover, we connected two of such networks aiming to model feature-binding through selectivity synchronization (2). In Chapter 4.2, we aim to clarify the mechanisms of working memory interference from previous memories (3), the so-called serial biases. These biases provide an excellent opportunity to contrast activity-based and activity-silent mechanisms because both mechanisms have been proposed to be the underlying cause of those biases. In Chapter 4.3, armed with the same techniques used to seek evidence for activity-silent mechanisms, we test a prediction of the bump-attractor model with short-term plasticity (4). Finally, in light of the results from aim 4 and simple computer simulations, we reinterpret previous studies claiming evidence for activity-silent mechanisms (5)

Controle da pressão arterial e dos fatores associados no grupo de hipertensos do Centro de Saúde Baixas em Inhuma - Piauí

A Hipertensão Arterial Sistêmica é uma condição clínica caracterizada por níveis elevados de pressão arterial. Sua detecção, tratamento e controle são fundamentais para a redução dos eventos cardiovasculares. Este plano de ação objetiva melhorar o acompanhamento e controle da PA em hipertensos tratados no Centro de Saúde Baixas, através da capacitação de toda equipe, busca ativa dos pacientes menos assíduos, realização de palestras, acompanhamento com educador físico e nutricionista, acompanhamento clínico ambulatorial onde serão avaliados rotineiramente e solicitado uso das medicações para controle da pressão arterial. A HAS é uma doença crônica que necessita da adesão rigorosa ao tratamento, associado a mudança de estilo de vida, com a prática de atividades físicas e mudança de hábitos alimentares, para controlar a PA e prevenir suas complicações. O envolvimento de toda equipe é importante para o paciente se sentir acolhido e motivado a continuar no tratamento

A SUSTENTABILIDADE FINANCEIRA DA UFS: ENTRAVES E ALTERNATIVAS

Este trabalho tem como objetivo analisar a composição dos recursos da Universidade Federal de Sergipe (UFS) apresentando os entraves e alternativas para ampliar a captação da receita. Explana uma abordagem histórica dos valores e fatos que definiram as fontes consolidadas de recursos no período de 1998 a 2008 da UFS e evidencia a importância do financiamento como lastro de sustentabilidade às políticas públicas educacionais. Para desenvolvimento da pesquisa foram utilizados os seguintes recursos: bibliografias inerentes ao tema, documentos contábeis extraídos do Sistema de Administração Financeira (SIAFI), do Governo Federal e, os Relatórios de Gestão do período compreendido neste trabalho. Dentre os resultados obtidos, destacam-se os seguintes: a captação de recursos por meio de descentralização de crédito, oriundos de projetos e parcerias, é uma alternativa para majorar os créditos orçamentários da instituição, posto que a dotação liberada pelo governo é limitada e; a UFS poderia, ainda, implementar a estratégia de inteligência para captação de recursos por meio de doações. Com relação à capacidade de execução orçamentária, a instituição praticamente realiza plenamente sua dotação

Muscidae (Diptera) of medico-legal importance associated with ephemeral organic substrates in seasonally dry tropical forests

Muscidae (Diptera) comprises one of the most important taxa in medical, veterinary and forensic entomology, especially due to their association with decomposing carcasses and cadavers. Yet, knowledge on their distribution and behaviour is still incipient in several biomes, which is the case of dry tropical forests. This study aimed to evaluate the attractiveness of different organic substrates to species of Muscidae in areas of seasonally dry forests (Caatinga) in Northern Brazil. Sampling was carried out in five Caatinga areas between 2015 and 2017, using suspended traps baited with bovine spleen, fish or human faeces. When all samplings were combined, 3,176 adults of nine species were collected. The assemblages of muscids had higher richness and abundances on bovine spleen, which attracted 66% of all specimens, when compared to the other substrates. Musca domestica was the most abundant species, and it was dominant in assemblages associated with spleen and fish. Assemblages attracted to spleen and fish had higher similarity, differing from those associated with faeces. Differences in food attractiveness are presented for species of medical interest as pathogen vectors (e.g., Synthesiomyia nudiseta (Wulp, 1883)) and of forensic relevance as colonizers of human corpses (e.g., Ophyra aenescens (Wiedemann, 1830))

Muscidae (Diptera) of medico-legal importance associated with ephemeral organic substrates in seasonally dry tropical forests

Muscidae (Diptera) comprises one of the most important taxa in medical, veterinary and forensic entomology, especially due to their association with decomposing carcasses and cadavers. Yet, knowledge on their distribution and behaviour is still incipient in several biomes, which is the case of dry tropical forests. This study aimed to evaluate the attractiveness of different organic substrates to species of Muscidae in areas of seasonally dry forests (Caatinga) in Northern Brazil. Sampling was carried out in five Caatinga areas between 2015 and 2017, using suspended traps baited with bovine spleen, fish or human faeces. When all samplings were combined, 3,176 adults of nine species were collected. The assemblages of muscids had higher richness and abundances on bovine spleen, which attracted 66% of all specimens, when compared to the other substrates. Musca domestica was the most abundant species, and it was dominant in assemblages associated with spleen and fish. Assemblages attracted to spleen and fish had higher similarity, differing from those associated with faeces. Differences in food attractiveness are presented for species of medical interest as pathogen vectors (e.g., Synthesiomyia nudiseta (Wulp, 1883)) and of forensic relevance as colonizers of human corpses (e.g., Ophyra aenescens (Wiedemann, 1830))

Products ´categorization and suppliers´ mix analysis / Categorização de produtos e a análise do mix de fornecedores

Purchase activity is increasingly becoming a strategic function. Therefore, it is necessary to achieve a better understanding of traded products, company´s real needs and the nature of supplier-purchaser relation. Thus, the study had as its goal the improvement of the profits center of the decoration products of a retail company in Teresina/Piauí/Brazil, aiming to subsidize the purchasing management and the suppliers mix analysis. In order to do so, a documental research was conducted with data referring to a one year´s period that was collected from sales report generated by the Integrated Commercial Automation System (SACI, the acronym in portuguese). Results indicate a new profits center structure and a reduction on the mix of suppliers associated with biggest accumulated sales value, thus becoming possible to feed the buying sector with information for strategic decision-making. To future researches, deepened analysis on costs related to these changes is suggested and, as practical action, similar analysis on the remaining sectors/families of registered products is encouraged.

The First Report on the Medicinal Use of Fossils in Latin America

There have been very few ethnopharmacological studies performed on the traditional use of fossil species, although a few records have been conducted in Asia, Africa, and Europe. This study is the first ever to be performed on the use of Testudine (turtle) fossils for folk medicine in Latin America. An investigation was conducted in the Araripe Basin, which is one of the most important fossil-bearing reserves in the world due to the diversity, endemism, and quality of preservation of its fossils. We propose the formalization of a new discipline called ethnopaleontology, which will involve the study of the dynamic relationship between humans and fossils, from human perception to direct use

Neural circuit basis of visuo-spatial working memory precision: A computational and behavioral study

The amount of information that can be retained in working memory (WM) is limited. Limitations of WM capacity have been the subject of intense research, especially in trying to specify algorithmic models for WM. Comparatively, neural circuit perspectives have barely been used to test WM limitations in behavioral experiments. Here we used a neuronal microcircuit model for visuo-spatial WM (vsWM) to investigate memory of several items. The model assumes that there is a topographic organization of the circuit responsible for spatial memory retention. This assumption leads to specific predictions, which we tested in behavioral experiments. According to the model, nearby locations should be recalled with a bias, as if the two memory traces showed attraction or repulsion during the delay period depending on distance. Another prediction is that the previously reported loss of memory precision for an increasing number of memory items (memory load) should vanish when the distances between items are controlled for. Both predictions were confirmed experimentally. Taken together, our findings provide support for a topographic neural circuit organization of vsWM, they suggest that interference between similar memories underlies some WM limitations, and they put forward a circuit-based explanation that reconciles previous conflicting results on the dependence of WM precision with load. Copyright © 2015 the American Physiological Society

Life post-death: Colonization of a bat carcass by Microcerella halli (Engel, 1931) (Diptera: Sarcophagidae) in a Neotropical cave

Caves are habitats characterized by low light or total darkness, whose fauna is largely composed of animals that adapt to dark environments, such as bats and many arthropods. Here, we present the first record of bat carcass colonization by Diptera larvae in a cave in the Neotropics. Twenty-one adult specimens of Microcerella halli (Sarcophagidae), seven males and 14 females, emerged from larvae collected in a carcass of Pteronotus gymnonotus (Mormoopidae) found in a twilight zone, about 15 m from the cave entrance. The mean time between carcass collection and adult emergence was 17.99 ± 0.44 days. As colonization by M. halli only occurs after death, we estimated the mean duration of the pupal stage – by recording daily pupation and emergence data – and attempted a preliminary estimate of the post-mortem interval, which indicated that larviposition occurred at least 24 h before carcass collection. Furthermore, we discussed the fact that M. halli females can find and colonize carcasses in low light environments, reinforcing the forensic potential of the species

Modelagem das operações de extração madeireira em regime de manejo sustentável na Amazônia : estudo de caso de um sistema de exploração

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Florestal, Programa de Pós-Graduação em Ciências Florestais, 2018.O objetivo geral, nesta pesquisa, foi entender e estimar os fatores que influenciam o rendimento das operações florestais envolvidas na extração de toras, visando estabelecer indicadores que colaborem com o planejamento da exploração florestal. Procurou-se modelar o tempo efetivo das operações de extração de madeira em função dos parâmetros peso da tora e distância da tora à trilha de arraste e da trilha até o pátio de estocagem de madeira. Foram realizadas tomadas de tempo dos elementos do ciclo operacional da extração florestal, calculado o volume individual de cada tora e determinados os rendimentos das operações. Os custos operacionais fixos e variáveis da extração florestal e o seu custo de produção também foram determinados. Procedeu-se à modelagem envolvendo o rendimento das operações com as variáveis distância (m) da tora a trilha de arraste, distância (m) da trilha ao pátio de estocagem e peso da tora por meio do método dos Mínimos Quadrados Ordinários. A eficiência operacional do guinchamento foi de 83,25% e a produtividade, de 31,12 m³ he-1, sendo o consumo de combustível e a mão de obra os elementos de maior contribuição para o custo operacional. Já a eficiência operacional do arraste foi de 91,83% e a produtividade, de 49,41 m³ he-1, em que o consumo de combustível e de óleo hidráulico foi o elemento com maior participação no custo operacional. O modelo proposto para as operações indica que o tempo efetivo cresce a uma taxa de 7,68% no guinchamento e de 0,90% no arraste, para cada aumento absoluto de um metro na distância percorrida. As seguintes conclusões foram extraídas do presente trabalho: (a) as variáveis distância métrica da tora ao pátio de estocagem de madeira e o peso unitário de cada tora influenciam o tempo de execução das operações; (b) o peso da tora guinchada e arrastada mostrou ser pouco significativo para explicar o tempo efetivo gasto nas operações analisadas neste estudo; (c) o tempo efetivo gastos nas operações mostrou ser sensível à distância percorrida pela tora e (d) o modelo log-lin se ajustou bem para prever o tempo efetivo gasto para a execução das operações de extração de madeira.The general objective of this research was to understand and estimate the factors influencing the yield of the logging operations involved in the extraction of logs, in order to establish indicators that collaborate with the forest exploitation planning. It was tried to model the effective time of the operations of extraction of wood according to the parameters weight of the log and distance of the log to the trail of drag and of the trail until the patio of storage of wood. Time elements were taken of the operational cycle of the forest extraction, calculated the individual volume of each log and determined the yields of the operations. The fixed and variable operational costs of the forest extraction and its cost of production were also determined. Modeling involving the performance of the operations with the variables distance (m) of the log, the trailing trail, distance (m) of the trail to the storage yard and log weight was done by means of the Ordinary Least Squares method. The operating efficiency of the boom was 83.25% and the productivity was 31.12 m³ he-1, with fuel consumption and labor being the main contributors to operating costs. On the other hand, the operational efficiency of the drag was 91.83% and the productivity was 49.41 m³ he-1, in which fuel and hydraulic oil consumption was the element with the highest participation in the operational cost. The proposed model for operations indicates that the effective time increases at a rate of 7.68% in the squeal and 0.90% in the drag, for each absolute increase of one meter in the distance traveled. The following conclusions were drawn from the present work: (a) the variables metric distance of the log to the wood storage yard and the unit weight of each log influence the execution time of the operations; (b) the weight of the towed and dragged log showed to be insignificant to explain the effective time spent in the operations analyzed in this study; (c) the actual time spent on operations showed to be sensitive to the distance traveled by the log and (d) the log-lin model adjusted well to predict the effective time spent for the execution of the logging operations