1,720,988 research outputs found
Development of a passive MEG stimulus for measurement of the binaural masking level difference
Get PDFThe ability to hear a target signal over background noise is an important aspect of efficient hearing in everyday situations. This mechanism depends on binaural hearing whenever there are differences in the inter-aural timing of inputs from the noise and the signal. Impairments in binaural hearing may underlie some auditory processing disorders, for example temporal-lobe epilepsies. The binaural masking level difference (BMLD) measures the advantage in detecting a tone whose inter-aural phase differs from that of the masking noise. BMLD’s are typically estimated psychophysically, but this is challenging in children or those with cognitive impairments. The aim of this doctorate is to design a passive measure of BMLD using magnetoencephalography (MEG) and test this in adults, children and patients with different types of epilepsy. The stimulus consists of Gaussian background noise with 500-Hz tones presented binaurally either in-phase or 180° out-of-phase between the ears. Source modelling provides the N1m amplitude for the in-phase and out-of-phase tones, representing the extent of signal perception over background noise. The passive BMLD stimulus is successfully used as a measure of binaural hearing capabilities in participants who would otherwise be unable to undertake a psychophysical task
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Exploring asymmetries from genes, to brains, to minds: a multimodal neuroimaging approach to the putative role of the NODAL signalling pathway in neurocognitive disorders via atypical cerebral lateralisation
Get PDFThis thesis investigates the relationship between functional and structural hemispheric asymmetries, by analysing brain anatomy, neurophysiology, neurocognitive and behavioural quantitative laterality measures, in a dyslexia family-based study. The main hypothesis developed and tested in the thesis is that atypical functional and structural hemispheric asymmetries might be the extended endophenotype of a disruption of the NODAL signalling pathway, at the level of the PCSK6 gene, becoming clinically visible during brain development as neurocognitive disorders. In this context, the putative association of PCSK6 rs11855415 genetic variant with developmental dyslexia is used as genotype-phenotype association model, according to which the PCSK6 rs11855415-related structural and functional hemispheric asymmetries are studied as its extended endophenotype, and investigated via a multimodal integrated neuroimaging approach. Within this multidimensional study, different levels of data were acquired from each participant, including: DNA sampling for genotyping, magnetic resonance imaging scans of the brain, magnetoencephalography assessment of receptive language, neurocognitive and handedness testing. By deriving and integrating quantitative measures of grey matter asymmetries, hemispheric language lateralisation and handedness dominance in children with developmental dyslexia and their siblings or twins, this thesis builds a prototypical model of the postulated extended endophenotype of functional and structural hemispheric asymmetries related to PCSK6 rs11855415 genetic variant
Neural Correlates of Developmental Dyslexia: A Multimodal Study of Typical and Atypical Reading
Get PDFDevelopmental dyslexia is the most common neurobehavioural disorder that can affect up to 17% of school-aged children. It is characterised by literacy difficulties in accurate and fluent word recognition. Previous research has made significant progress into studying the behavioural, cognitive and neurobiological causes of the reading disability. More recently, important advances into understanding the neural circuits and the aetiology of dyslexia has come from, respectively, brain imaging and genetic findings. Although neuroimaging studies have been able to identify the cortical areas involved in the reading deficit, the high heterogeneity in dyslexic traits still remains poorly investigated. The aim of this research was to expand on the previous findings by offering a thorough investigation of brain networks underlying complex symptoms of dyslexia. For this reason, a multimodal cognitive, genetic, structural and functional neuroimaging approach was employed. First, different dyslexic functional networks were identified by studying MEG resting state functional connectivity and network topology. In particular, an un-biased graph theory measure, the minimum spanning tree, was used to portray frequency specific connectomes in relation to fluency and genetic components. Second, a novel MEG paradigm was designed to delineate time-specific neural correlates and dynamic oscillatory activity in the first stages of reading processing, the prelexical orthographic visual word recognition, in typical and dyslexic readers. Third, structural connectivity, by means of diffusion tensor imaging (DTI), was investigated in typical and atypical readers. The outcome of each of these studies demonstrates how a correlational cognitive-genetic-neuroimaging method is fundamental to be able to distinguish neural mechanisms and brain networks underpinning different dyslexic phenotypes. Overall, the results of this work provide a strong case for the design and the application of a multimodal (cognitive, genetic, structural and functional neuroimaging) approach to examine neurobiological correlates of typical and atypical reading development, and better define the dyslexic continuum
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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