37 research outputs found
Highly Scalable Parallel Processing of Extracellular Recordings of Multielectrode Arrays
No full textTechnological advances of Multielectrode Arrays (MEAs) used for multi- site, parallel electrophysiological recordings, lead to an ever increasing amount of raw data being generated. Arrays with hundreds up to a few thousands of
electrodes are slowly seeing widespread use and the expectation is that more sophisticated arrays will become available in the near future.
In order to process the large data volumes resulting from
MEA recordings there is a pressing need for new software tools able to process many data channels in parallel. Here we present a new tool for processing MEA data recordings that makes use of new programming paradigms and recent technology developments to unleash the power of modern highly parallel hardware, such as multi-core CPUs with vector instruction sets or GPGPUs.
Our tool builds on and complements existing MEA data
analysis packages. It shows high scalability and can be used to speed up some performance critical pre-processing steps such as data filtering and spike detection, helping to make the analysis of larger data sets tractable
Automated classification of behavioural and electrophysiological data in Neuroscience
No full textDue to technological advances the amount of data that can be collected in modern science is increasing every day and neuroscience is no exception. Integrating large amounts of data at different spatial and temporal scales is essential for uncovering the underlying mechanisms of the brain but poses also new challenges since drawing conclusions from vast amounts of data is increasingly difficult. New automated and fast analysis methods that can make sense of large and complex data sets are therefore in need and will become increasingly important in the years and decades ahead. This work proposes new tools for the analysis of two important types of data commonly found in neuroscience. The first is behavioural data from rodent navigation tasks in the form of animal movement paths. Two novel classification methods based on machine learning algorithms are proposed here. The methods are able to automatically or semi-automatically reduce the complex movement paths of the animals to a series of stereotypical types of behaviour, leading toboth more detailed and consistent results. The second type of data considered here is electrophysiological data, in the form of extracellular multielectrode array (MEA) recordings which can record the electrical activity of thousands of neurons in parallel over long periods of time. Here a new highly-parallel data processing tool which can reduce the MEA data to a series of spike trains is presented. The tool can serve as basis for more sophisticated analyses like the reconstruction of the individual cell spike trains, for which machine learning methods are again essential. The results presented here show that machine learning algorithms and parallel processing architectures are both fundamental tools for coping with large and complex data sets, like the ones found in modern neuroscience
Desenvolvimento de complexos de AlIIIZnII e AlIIICuII: biomiméticos para as fosfatases ácidas púrpuras substituídas
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2009Foram sintetizados dois novos complexos binucleares de valência mista de AlIIIMII com uma estrutura contendo o núcleo AlIII(µ-OH)MII, onde o MII = Zn e Cu. O ligante utilizado para tal é o ligante não-simétrico H2bpbpmp que já é amplamente conhecido e bem caracterizado na literatura. Estes novos complexos possuem uma estrutura inspirada no sítio ativo de uma metalohidrolase, a Fosfatase Ácida Púrpura (PAP). Sabe-se que modelos biomiméticos inspirados no sítio ativos das PAP´s possuem atividade catalítica frente a hidrólise de ésteres de fosfato, proteínas e DNA. Logo se propõe neste trabalho o estudo destes complexos frente à hidrólise dos ésteres de fosfato bis(2,4-dinitrofenil)-fosfato e do 2,4-dinitrofenil-fosfato, onde estes mostraram possuir atividade catalítica. Para estes estudos foi utilizado o modelo de cinética enzimática de Michaelis-Menten e determinados seus parâmetros cinéticos
"Cava a cova!": descrevendo o humor da cena dos coveiros de Hamlet em duas traduções brasileiras
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Estudos da Tradução, Florianópolis, 2013.Em estudos acadêmicos, como os Estudos da Tradução, por exemplo, a pesquisa é feita para preencher uma lacuna, entretanto os pesquisadores apresentam dificuldades em como conduzir o projeto de pesquisa, qual a metodologia a ser usada para sustentar a pesquisa. A famosa máxima ?Um problema bem colocado é resolvido pela metade?, no ver da pesquisa científica, não deixa de ser verdade; mas faz-se necessária uma formulação do problema, de modo que irá clarear o objetivo do projeto de pesquisa. (KRUGER; WALLMARCH, 1997, p. 120). Esta dissertação tem como objetivo fazer uma análise descritivo-comparativa do humor shakespeariano em duas traduções brasileiras da cena dos coveiros da peça A Tragédia de Hamlet: Príncipe da Dinamarca, de William Shakespeare (2005). Entende-se por humor os recursos textuais e discursivos passíveis de gerar o riso presentes no original e como estes elementos foram transpostos nas traduções da referida cena na peça shakespeariana por Millôr Fernandes e Carlos Alberto Nunes, esta publicada em 1983 e aquela em 1955, porém será a usada a reimpressão de 2011 de ambas. Inicialmente, pretende-se introduzir a questão da tradução do humor em Shakespeare, com base em estudos de Dirk Delabastita (1996) e Stanislaw Baranckzak (1992), e depois analisar a cena dos coveiros pelo modelo descritivo proposto por José Lambert & Hendrik Van Gorp (2011). Junto com o modelo descritivo, unimos a Teoria Geral do Humor Verbal de Salvatore Attardo (2002) e os procedimentos técnicos de Jean Paul Vainay & Jean Darbelnet (in VENUTI, 2004), como teorias voltadas ao processo tradutório com seus mecanismos de funcionamento. Como resultado final, pôde-se notar que ambos os tradutores souberam transpor a comicidade no texto shakespeariano, mantendo o tom ambíguo, irônico e sarcástico que o humor sugere.<br
RodentDataAnalytics/mwm-ml-gen: Version 4.0-beta
No full text<p>Major Changes</p>
<p>A number of new functionalities are available:</p>
<ul>
<li>Ability to label whole trajectories</li>
<li>Ability to turn non-segmented trajectories into segments</li>
<li>Ability to add custom class tags</li>
<li>Ability to load custom computed trajectory features</li>
<li>More analysis results including confidence intervals and classification statistics.</li>
<li>Raw classification results are now exported for further custom analysis (or in case the Friedman test cannot be performed).</li>
</ul>
<p>Minor Changes</p>
<ul>
<li>Fixed axes labels and file names.</li>
<li>Better figure graphics.</li>
<li>Some parts of the code have been re-written.</li>
<li>Ability to read UTF16LE txt files.</li>
</ul>
<p>Bugs and issues fixed</p>
<ul>
<li>New more robust classification methodology (see issue).</li>
</ul>
Single-Material Graphene Thermocouples
No full textOn‐chip temperature sensing on a micro‐ to nanometer scale is becoming more desirable as the complexity of nanodevices keeps increasing and their downscaling continues. The continuation of this trend makes thermal probing and management more and more challenging. This highlights the need for scalable and reliable temperature sensors, which have the potential to be incorporated into current and future device structures. Here, it is shown that U‐shaped graphene stripes consisting of one wide and one narrow leg form a single material thermocouple that can function as a self‐powering temperature sensor. It is found that the graphene thermocouples increase in sensitivity with a decrease in leg width, due to a change in the Seebeck coefficient, which is in agreement with previous findings and report a maximum sensitivity of ΔS ≈ 39 μV K−1
Detailed classification of swimming paths in the Morris Water Maze: multiple strategies within one trial
No full textThe Morris Water Maze is a widely used task in studies of spatial learning with rodents. Classical performance measures of animals in the Morris Water Maze include the escape latency, and the cumulative distance to the platform. Other methods focus on classifying trajectory patterns to stereotypical classes representing different animal strategies. However, these approaches typically consider trajectories as a whole, and as a consequence they assign one full trajectory to one class, whereas animals often switch between these strategies, and their corresponding classes, within a single trial. To this end, we take a different approach: we look for segments of diverse animal behaviour within one trial and employ a semi-automated classification method for identifying the various strategies exhibited by the animals within a trial. Our method allows us to reveal significant and systematic differences in the exploration strategies of two animal groups (stressed, non-stressed), that would be unobserved by earlier methods
Analysis of behaviour in the Active Allothetic Place Avoidance task based on cluster analysis of the rat movement motifs
No full textAbstractThe Active Allothetic Place Avoidance test (AAPA) is a useful tool to study spatial memory in a dynamic world. In this task a rat, freely moving on a rotating circular arena, has to avoid a sector where shocks are presented. The standard analysis of memory performance in the AAPA task relies on evaluating individual performance measures. Here we present a new method of analysis for the AAPA test that focuses on the movement paths of the animals and utilizes a clustering algorithm to automatically extract the stereotypical types of behaviour as reflected in the recorded paths. We apply the method to experiments that study the effect of silver nanoparticles (AgNPs) on the reference memory and identify six major classes of movement motifs not previously described in AAPA tests. The method allows us to analyse the data with no prior expectations about the motion to be seen in the experiments.</jats:p
Techno-economic transition towards a hydrogen economy
No full textPhDThe research conducted is in the field of innovation and focuses on the UK energy sector. The key theme of the study is the transition towards a hydrogen economy with fuel cell technologies at the epicentre and takes into account the relevant scientific, technological, economic and policy issues. In order to provide an understanding of the factors that affect techno-economic transitions to alternative energy systems, the thesis investigates the historical transition processes such as the transition to electrification in the early 1900s and recent transitions to CCGT and renewable energy systems (wind, biofuels and solar) that have taken place since the late 1980s. As the developmental status of hydrogen technologies lay at the heart of these transitions, a thorough analysis of the hydrogen and fuel cell technologies, the R&D requirements, and innovations required in different scientific fields (including materials science) to develop these technologies is conducted. At the same time, as other factors such as sustainability, climate change and security of supply concerns can greatly affect the direction of the transition processes, that includes R&D activities and investment in alternative energy technologies, an overview of these factors is also provided. The analysis employs a new theoretical framework that combines two well established theories in the literature, Techno-economic Transitions and Large Technological Systems. By using this new framework, the technological transition towards a hydrogen energy system can be analysed at three levels, (global, national and local). The analysis is narrowed down to the local level in order to determine the timing of a transition in London and how it can form the foundation for a wider a transition at the national level based on alternative technologies
