A review and consideration on the kinematics of reach-to-grasp movements in macaque monkeys

The bases for understanding the neuronal mechanisms that underlie the control of reach-to-grasp movements among nonhuman primates, particularly macaques, has been widely studied. However, only a few kinematic descriptions of their prehensile actions are available. A thorough understanding of macaques' prehensile movements is manifestly critical, in light of their role in biomedical research as valuable models for studying neuromotor disorders and brain mechanisms, as well as for developing brain-machine interfaces to facilitate arm control. This article aims to review the current state of knowledge on the kinematics of grasping movements that macaques perform in naturalistic, semi-naturalistic, and laboratory settings, to answer the following questions: Are kinematic signatures affected by the context within which the movement is performed? In what ways is kinematics of humans' and macaques' prehensile actions similar/dissimilar? Our analysis reflects the challenges involved in making comparisons across settings and species due to the heterogeneous picture in terms of the number of subjects, stimuli, conditions, and hands used. The kinematics of free-ranging macaques are characterized by distinctive features that are exhibited neither by macaques in laboratory setting nor human subjects. The temporal incidence of key kinematic landmarks diverges significantly between species, indicating disparities in the overall organization of movement. Given such complexities, we attempt a synthesis of extant body of evidence, intending to generate some significant implications for directions that future research might take, to recognize the remaining gaps and pursue the insights and resolutions to generate an interpretation of movement kinematics that accounts for all settings and subjects

The impact of brain lateralization and Anxiety-Like behaviour in an extensive operant conditioning task in Zebrafish (Danio rerio)

© 2019 by the authors. Several studies in mammals, birds, and fish have documented better cognitive abilities associated with an asymmetrical distribution of cognitive functions in the two halves of the brain, also known as 'functional brain lateralization'. However, the role of brain lateralization in learning abilities is still unclear. In addition, although recent studies suggest a link between some personality traits and accuracy in cognitive tasks, the relation between anxiety and learning skills in Skinner boxes needs to be clarified. In the present study, we tested the impact of brain lateralization and anxiety-like behaviour in the performance of an extensive operant conditioning task. Zebrafish tested in a Skinner box underwent 500 trials in a colour discrimination task (red vs. yellow and green vs. blue). To assess the degree of lateralization, fish were observed in a detour test in the presence of a dummy predator, and anxiety-like behaviour was studied by observing scototaxis response in an experimental tank divided into light and dark compartments. Although the low performance in the colour discrimination task did not permit the drawing of firm conclusions, no correlation was found between the accuracy in the colour discrimination task and the behaviour in the detour and scototaxis tests. This suggests that neither different degrees of asymmetries in brain lateralization nor anxiety may significantly impact the learning skills of zebrafish

Projeto voltado à manufatura aditiva utilizando impressão 3D SLA e otimização topológica

Manufatura aditiva conquista cada vez mais espaço dentro da indústria e, aliada a potentes ferramentas de projeto, estimula a produção de componentes mecânicos com geometrias cada vez mais arrojadas visando o melhor aproveitamento de recursos. Todavia, alguns fatores limitam a aplicação de tais métodos, principalmente no que diz respeito à dificuldade técnica de prever o comportamento mecânico dos componentes produzidos. Este trabalho propõe e testa uma metodologia para o projeto de componentes mecânicos fabricados por impressão 3D SLA, utilizando o método de otimização topológica para minimização da flexibilidade. O material utilizado é caracterizado por ensaios mecânicos e, por meio da utilização de restrição de tensão no problema de otimização, visa-se viabilizar o projeto. A realização das análises numéricas utilizando o método de elementos finitos e das otimizações é feita utilizando o software comercial ANSYS (versão 19.1). As topologias finais são impressas usando impressão 3D SLA e sujeitas a ensaios mecânicos, reproduzindo as condições de contorno utilizadas no caso numérico, para validar a metodologia. Por meio de exemplos numéricos e experimentais, se mostra a eficiência da metodologia proposta.Additive manufacturing conquers a bigger participation in the industry and, combined with powerful design tools, encourages the production of mechanical components with bolder geometries aiming to better utilize resources. Nevertheless, its application is still limited by some factors, mostly regarding the technical difficulty to predict the mechanical behaviors of the fabricated components. This paper proposes and tests a design methodology for mechanical components produced by 3D SLA printing, using topology optimization to minimize their compliance. The material used is characterized by tensile tests and through the application of a stress constrain in the optimization problem, it is intended to qualify the project. The numerical simulations using the finite element method and the topology optimizations are performed utilizing the commercial software ANSYS (release 19.1). The final topologies are printed by 3D SLA printing and subjected to mechanical tests, reproducing the boundary conditions of the numerical case, to validate the methodology. Through numerical and experimental examples, the efficiency of the proposed methodology is shown

Usporedna studija doze zračenja hipotetske nesreće u istraživačkom reaktoru

This study is a contribution for radiation dose calculations of a hypothetical accident of a 1 MW research reactor Triga Mark II using HotSpot code. A postulated accidental release of noble gases and halogens were considered. The total effective dose (TED) was estimated for 1 day and 50 years after release. The total damage of fuel element cladding with a maximum radioactivity was considered. The obtained results show minimal TED values at the beginning of the release and at a shorter distance from the source. The maximum calculation results are acceptable and below the recommended public dose limit.Ovo istraživanje doprinos je izračunima doze zračenja hipotetske nesreće istraživačkog reaktora Triga Mark II od 1 MW primjenom HotSpot koda. Razmatrano je slučajno oslobađanje plemenitih plinova i halogena. Određena je vrijednost ukupne učinkovite doze nakon 1 dana i nakon 50 godina. Razmatrano je ukupno oštećenje obloge dijela s maksimalnom radioaktivnošću. Dobiveni rezultati pokazuju minimalne vrijednosti ukupne učinkovite doze na početku ispuštanja i na manjoj udaljenosti od izvora. Maksimalni rezultati izračuna su prihvatljivi i ispod preporučenog doznog ograničenja

4-Methyl­anilinium nitrate

The asymmetric unit of the title compound, C7H10N+·NO3 −, consists of a 4-methyl­anilinium cation protonated at the amino group and a nitrate anion. In the crystal, anions and cations are linked through N—H⋯O and N—H⋯(O,O) hydrogen bonds, buiding a corrugated layer structure parallel to (001)

Estratégias de cobertura vacinal para o sarampo em crianças não vacinadas : uma revisão integrativa

O estudo trata-se de uma revisão integrativa (RI) que teve por objetivo identificar a produção de conhecimento sobre as estratégias de cobertura vacinal para o sarampo em criança não vacinadas. A busca realizada nas bases de dados PubMed, SciELO e na revista The New England Journal of Medicine, resultou em 5.988 artigos. Após aplicação dos critérios de inclusão e exclusão, restaram 18 artigos para a análise que respondiam à questão norteadora. Em seguida, na leitura íntegra dos artigos selecionados foram encontradas um total de 52 estratégias de cobertura vacinal para o sarampo em crianças não vacinadas. Ao realizar uma análise da qualidade das estratégias, foram excluídas 15 pois se encontravam repetidamente, restando 37 estratégias que foram analisadas quanto ao aumento da taxa de cobertura vacinal para o sarampo e se conseguiu atingir a faixa de segurança recomenda de 95%, validando a sua eficácia na promoção da imunidade ou no controle de surtos de sarampo. Na análise das estratégias 22% dos estudos atingiram a meta estimada de 95% de cobertura vacinal os 94% demostraram aumento das taxas. Por isso a aplicação das estratégias de cobertura vacinal para o sarampo em crianças não vacinas tem eficácia. Além de promover a educação dos vacinadores e fortalecer a supervisão da aplicação das vacinas para que as crianças recebam adequadamente e que não existe uma estratégia de cobertura vacinal superior única, o tempo influenciará as preferências na escolha das estratégias, principalmente avaliando o quadro endêmico das regiões de surtos de sarampo e dos referenciais registrados no sistema de saúde de vacinação da população alvo. A revisão de literatura demostrou que utilizar um conjunto de seis ou mais estratégias pode atingir eficiência e resultado esperado. Com esse estudo conta-se que a vacinação infantil é um assunto sério e prioritário, merecendo estudo contínuo das estratégias. A enfermeira pode ser criadora de estratégias de cobertura vacinal frente aos cenários de epidemia de sarampo e partir deles produzir literatura científica sustentada.Resumo não disponível

Laterality Enhances Numerical Skills in the Guppy, Poecilia reticulata

It has been hypothesized that cerebral lateralization can significantly enhance cognition and that this was one of the primary selective forces shaping its wide-spread evolution amongst vertebrate taxa. Here, we tested this hypothesis by examining the link between cerebral lateralization and numerical discrimination. Guppies, Poecilia reticulata, were sorted into left, right and non-lateralized groups using a standard mirror test and their numerical discrimination abilities tested in both natural shoal choice and abstract contexts. Our results show that strongly lateralized guppies have enhanced numerical abilities compared to non-lateralized guppies irrespective of context. These data provide further credence to the notion that cerebral lateralization can enhance cognitive efficiency

Does Brain Lateralization Affect the Performance in Binary Choice Tasks? A Study in the Animal Model Danio rerio

Researchers in behavioral neuroscience commonly observe the behavior of animal subjects in the presence of two alternative stimuli. However, this type of binary choice introduces a potential confound related to side biases. Understanding whether subjects exhibit this bias, and the origin of it (pre-existent or acquired throughout the experimental sessions), is particularly important to interpreting the results. Here, we tested the hypothesis according to which brain lateralization may influence the emergence of side biases in a well-known model of neuroscience, the zebrafish. As a measure of lateralization, individuals were observed in their spontaneous tendencies to monitor a potential predator with either the left or the right eye. Subjects also underwent an operant conditioning task requiring discrimination between two colors placed on the left–right axis. Although the low performance exhibited in the operant conditioning task prevents firm conclusions from being drawn, a positive correlation was found between the direction of lateralization and the tendency to select the stimulus presented on one specific side (e.g., right). The choice for this preferred side did not change throughout the experimental sessions, meaning that this side bias was not the result of the prolonged training. Overall, our study calls for a wider investigation of pre-existing lateralization biases in animal models to set up methodological counterstrategies to test individuals that do not properly work in a binary choice task with stimuli arranged on the left–right axis