1,721,070 research outputs found
Influence of the Month of Birth and Persistence of ADHD in Prospective Studies: Protocol for an Individual Patient Data Meta-Analysis
No full textIntroduction: attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder with symptoms, especially the hyperactive ones, that tend to decrease in severity with age. Interestingly, children born just before the school-entry cut-off date (i.e., the youngest pupils of a classroom) are at higher risk of being diagnosed with ADHD compared to children born just after the cut-off date. Noteworthy, this month-of-birth effect tends to disappear with increasing absolute age. Therefore, it is possible that young children erroneously diagnosed with ADHD due to their month of birth present a lower chance to have their diagnosis confirmed at later age, artificially reinforcing the low persistence of ADHD across the lifespan. This protocol outlines an individual patient data (IPD) meta-analysis of prospective observational studies to explore the role of month of birth in the low persistence of ADHD across the lifespan. Methods and analysis: five databases will be systematically searched in order to find prospective observational studies where the presence of ADHD is assessed both at baseline and at a follow-up of at least four years. We will use a two-stage IPD meta-analytic approach to estimate the role of month of birth in the persistence of ADHD. Various sensitivity analyses will be performed to assess the robustness of the results. Ethics and dissemination: no additional data will be collected and no deidentified raw data will be used. Ethics approval is thus not required for the present study. Results of this IPD meta-analysis will be submitted for publication in a peer-reviewed journal
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
Load and the spatial profile of visual selective attention
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Le profil spatial de l'attention visuelle sélective
No full textThèse débutée: 01/10/2005 Thèse soumise: 29/09/2009 Thèse soutenue: 08/01/2010Selective attention has been hypothesised to operate at a perceptual level by focusing perceptual resources on the attended location (Lavie, 1995). This thesis examined (1) the shape of the profile of perceptual resources in space and (2) the effect of several factors on the focus of this profile. The spatial profile of perceptual resources was indexed using different measures, namely, a range of measures of distractor interference in the flanker task (Eriksen & Hoffmann, 1972) and performance at detecting a probe in the cue/probe task (Posner, 1980). In all cases, the profile was found to describe a Mexican-hat pattern and this was true whether attention was directed at fixation or to the periphery. The effects of a number of factors on the focus of the Mexican-hat profile, namely, on the efficiency of the perceptual level of selective attention, were investigated. While increasing both perceptual load (i.e., the perceptual difficulty of extracting information) and trait anxiety caused the profile to focus, increasing cognitive load (i.e., the difficulty of a mental task performed in parallel to the selective-attention task) caused it to defocus. These results have two important implications. First, variations in stimulus and task properties (e.g., load) or in individual characteristics (e.g., anxiety) across studies may explain why some studies have reported gradient rather than Mexican-hat patterns; in some studies, perceptual resources may have been defocused, causing the Mexican-hat profile to look like a gradient. Second, contrary to the load theory (Lavie, Hirst, de Fockert, & Viding, 2004), the focus of perceptual resources is controlled not only at perceptual but also at cognitive levels. Cognitive load may therefore change what we see, whether it be an individuated object or the global properties of a scene.Il a été suggéré (ex. Lavie, 1995) que l'attention visuelle opère en focalisant les « ressources perceptives » sur un endroit donné de la scène visuelle. La présente thèse s'intéresse (1) au profil spatial, c'est-à-dire la répartition dans l'espace visuel, des ressources perceptives et (2) aux effets de plusieurs facteurs sur la focalisation des ressources perceptives. Le profil spatial des ressources perceptives est indexé en utilisant plusieurs mesures, notamment un ensemble de mesures d'interférence (produite par des distracteurs) dans la tâche d'Eriksen (Eriksen & Hoffmann, 1972) et une mesure de performance à détecter une cible (apparaissant à un emplacement attendu ou non) dans la tâche de Posner (Posner, 1980). Dans tous les cas, le profil obtenu décrit un ‘chapeau mexicain' et cela est vrai que l'attention visuelle soit dirigée vers le centre ou vers la périphérie du champ visuel. Les effets de plusieurs facteurs sur la focalisation du ‘chapeau mexicain', c'est-à-dire sur l'efficience de l'attention visuelle, sont ensuite explorés. Tandis qu'augmenter la charge perceptive (la difficulté à extraire l'information perceptuelle) et l'anxiété causent une focalisation attentionnelle (c.à.d. un chapeau mexicain plus comprimé), augmenter la charge cognitive (la difficulté d'une tâche mentale effectuée en parallèle de la tâche d'attention visuelle) causent une défocalisation attentionnelle (c.à.d. un chapeau mexicain plus étalé). Ces résultats ont deux implications importantes. Tout d'abord, des différences au niveau des propriétés des stimuli et de la tâche (ex. charges perceptives ou cognitives) ou des caractéristiques individuelles (ex. anxiété) entre différentes études peuvent expliquer pourquoi certaines études ont rapporté un profil attentionnel décrivant un simple « gradient » et d'autres un profil attentionnel décrivant un « chapeau Mexicain » ; dans certaines études, les ressources perceptives étaient plus défocalisées, faisant passer un chapeau mexicain pour un gradient. Deuxièmement, contrairement à ce qui est suggéré dans l'influente théorie sur les charges perceptives et cognitives (Lavie, Hirst, de Fockert, & Viding, 2004), la focalisation des ressources perceptives n'est pas seulement contrôlée à un niveau perceptif, elle est aussi contrôlée à un niveau cognitif. Charger les processus cognitifs affecterait ce que l'on voit, entre un objet isolé (ex. l'arbre) ou les propriétés plus globales de la scène (ex. la forêt)
Percevoir l’arbre ou la forêt : Impact de l’exposition urbaine sur le biais perceptuel.
No full textInternational audienc
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