1,720,968 research outputs found
Morfometria cerebrale nell’epilessia del lobo temporale: modelli di atrofia e connettività corticale e sottocorticale
No full textL’epilessia del lobo temporale (TLE) è la forma più comune tra le epilessie focali. È riconosciuta come una malattia di network, che determina perdita di volume sottocorticale, atrofia corticale e degenerazione della materia bianca. Quando le crisi interessano le strutture che compongono il lobo temporale mesiale parliamo di epilessia del lobo temporale mesiale (MTLE). La forma più comune di MTLE è la sclerosi ippocampale, caratterizzata da un’atrofia delle strutture dell’ippocampo. Sebbene l’elettroencefalografia (EEG) sia lo strumento più utilizzato per fare diagnosi di epilessia, le metodologie di neuroimaging si sono rivelate essenziali per rilevare anomalie strutturali, funzionali e metaboliche associate alla malattia.
L'obiettivo di questa tesi è esplorare i diversi modelli strutturali alla base della TLE, con particolare riguardo alle diverse eziologie. La metodologia applicata concerne la misurazione di numerose caratteristiche cerebrali, come lo spessore corticale della materia grigia, i volumi corticali e sottocorticali e la connettività della materia bianca, utilizzando come input le sequenze 3D-T1 (per la segmentazione della materia grigia e bianca, e per la volumetria), e le sequenze DTI per la valutazione della connettività della materia bianca e delle sue alterazioni microstrutturali.
La prima parte di questa tesi si è concentrata sull'esplorazione delle strutture sottocorticali coinvolte nella TLE. In particolare, i nostri studi hanno evidenziato il ruolo dell'amigdala e dei suoi nuclei in diversi tipi di TLE. Recentemente, un aumento del volume dell'amigdala è stato proposto come biomarcatore morfologico di un sottotipo di pazienti con TLE senza anomalie alla risonanza magnetica. Tuttavia, gli studi precedenti hanno trattato l'amigdala come un'unica entità sebbene questa struttura sia composta da diversi nuclei, ciascuno con particolari caratteristiche funzionali. Per questo motivo, è stato condotto un primo studio su una popolazione ben selezionata di pazienti TLE con sclerosi dell'ippocampo e con risonanza magnetica negativa. L'obiettivo è stato quello di esplorare il diverso comportamento delle sottostrutture dell'amigdala e di mappare la partecipazione di nuclei amigdaloidei in pazienti con o senza lesioni strutturali rilevate dalla risonanza magnetica. A nostra conoscenza, questo è il primo studio sulle sottostrutture dell'amigdala in una popolazione con TLE.
In seguito a questi risultati, il nostro interesse sul ruolo dell'amigdala nella TLE è stato esteso ai pazienti con una sintomatologia di Apnea Centrale Ictale (ICA). Recentemente, le manifestazioni ICA sono state considerate come un potenziale indice localizzatorio della TLE, in questo studio abbiamo dunque ipotizzato un possibile coinvolgimento dell'amigdala nella rete epilettogena.
La seconda parte della tesi riguarda uno studio condotto in collaborazione con il laboratorio della Dott.ssa McDonald presso l'Università della California, San Diego (UCSD). In questo studio, abbiamo cercato di determinare i processi biologici che sottendono le lesioni della materia grigia e bianca corticale in una popolazione TLE ampia ed eterogenea. Esistono prove che l'atrofia corticale e le lesioni della materia bianca seguano modelli spaziali differenti nella TLE; pertanto, abbiamo cercato di determinare se il danno alle materie grigia e bianca corticale possa essere correlato e se la loro associazione possa essere mediata da variabili associate alla malattia, come ad esempio la cronicità.
In sintesi, questa tesi mira a determinare la morfometria cerebrale che sta alla base della TLE e la sua implicazione clinica. In particolare, la maggior parte delle nostre ricerche si è concentrata sulle diverse eziologie che caratterizzano la TLE e sul potenziale impatto clinico di tali alterazioni strutturali nelle diverse classificazioni della malattia.Temporal Lobe Epilepsy (TLE) is the most common form of focal epilepsy. It is recognized as a network disease, involving subcortical volume loss, cortical atrophy, and loss of white matter integrity. When the seizure focus involved the medial temporal lobe structures, is named medial temporal lobe epilepsy (MTLE). The commonest MTLE is characterized by a hippocampal volume loss called hippocampal sclerosis (HS). Electroencephalography (EEG) is certainly the most widely used tool for diagnosing epilepsy. However, neuroimaging methodologies are also essential for detecting structural, functional, or metabolic abnormalities.
This thesis’ aims are to explore different structural abnormalities patterns underlying TLE, particularly regarding different etiologies. The methodology applied herein reflects the measurements of many anatomical features of the brain, like gray matter cortical thickness, cortical and subcortical volumes, and white matter connectivity using as inputs the T1-weighted tridimensional sequences (for the grey and white matter segmentation and volumetric measurements) and diffusion-weighted sequences for instead the evaluation of the white matter connectivity and microstructural alterations.
The first part of this thesis has focused on exploring the subcortical structures involved in TLE. Particularly, our studies highlighted the role of the amygdala and its nuclei in different types of TLE. Recently, an increase in amygdala volumes (i.e., amygdala enlargement) has been proposed as a morphological biomarker of a subtype of TLE patients without MRI abnormalities. However, previous studies treated the amygdala as a single entity, while instead it is composed by different nuclei, each with a particular function and connection. Hence, a first study was conducted on a well-selected TLE population with hippocampal sclerosis and non-lesional TLE, our purpose was to explore the different behavior of amygdala substructures, and map specific amygdalae nuclei participation in patients with or without structural lesions detected by the MRI scans. To our knowledge, this was the first study on amygdalae substructures in a TLE population.
Subsequently to these results, our interest in the role of the amygdala in TLE was extended to those patients with symptomatic Ictal Central Apnea (ICA). ICAs have been recently considered a potential localizing sign in TLE and we hypnotized a possible amygdala involvement in the epileptogenic network.
The second part of the dissertation concern a study conducted in collaboration with Dr. McDonald’s lab at the University of California, San Diego (UCSD). In this study, we seek to determine the biological processes underlying cortical gray and white matter injury in a large and heterogeneous TLE population. There is evidence that cortical atrophy and white matter injury follow different spatial patterns in TLE, thus, we aimed to determine if cortical gray and white matter damage could be correlated and if their associations could be mediated by disease-related variables, like chronicity.
In summary, this thesis aims to determine the brain morphometry involved in TLE and its clinical implication. Particularly, most of our research had been focused on the different etiologies that characterized TLE and the potential clinical yields of the structural changes across different disease classifications
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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