Dissertations / Theses on the topic 'Identification de lettre'

L’objectif de ce travail de thèse était d’étudier l’implication des systèmes visuels magnocellulaire et parvocellulaire dans le traitement de langage écrit, spécialement dans l’identification des mots. Quatre études expérimentales ont été réalisées afin de documenter le rôle respectif de ces deux systèmes pour différentes composantes de la structure du mot écrit, la lettre (Etude 1), la longueur du mot (Etude 2) et l’enveloppe du mot (Etude 3), ainsi que le voisinage orthographique (Etude 4). La dissociation des deux sous-systèmes visuels se fondait sur leurs caractéristiques fonctionnelles spécifiques : sensibilité aux fréquences spatiales basses et au contraste de luminance pour le système magnocellulaire ; sensibilité aux fréquences spatiales moyennes et élevées et au contraste chromatique pour le système parvocellulaire. Les participants étaient des adultes jeunes normolecteurs et des enfants de 10-11 ans, lecteurs novices, afin d’envisager l’implication de chaque système visuel à deux étapes de leur développement : maturité chez l’adulte jeune ; en cours de maturation chez l’enfant. Les résultats ont confirmé le rôle prépondérant des traitements parvocellulaires, ce qui corroborait le privilège accordé au traitement des lettres et traits des lettres dans la reconnaissance visuelle des mots. Le traitement de la longueur du mot s’est en revanche révélé être une dimension sélectivement magnocellulaire. L’ensemble des résultats est discuté dans le cadre de l’approche coarse-to-fine
The main objective was to study the implication of the magnocellular and the parvocellular visual systems in written language processing, specifically in word identification. Four studies were carried out to document the respective roles of these two systems, for different components of the written word structure, the letter (Study 1), the word length (Study 2), the word shape (Study 3) and the orthographic neighborhood (Study 4). The dissociation of the two visual systems was based on their specific functional characteristics: sensitivity to low spatial frequencies and luminance contrast for the magnocellular system; and sensitivity to medium and high spatial frequencies and chromatic contrast for the parvocellular system. The participants were young adult normal readers and 10-11 years-old children, novice readers, in order to consider the involvement of each visual system at two stages of their development: mature in young adults while still maturing in the children. The results confirmed the prominent role of parvocellular processing, which was consistent with the privilege accorded to the processing of letters and letters features in visual word recognition. On the other hand, word length processing has been shown to be a selectively magnocellular dimension. All results are discussed in the framework of the coarse-to-fine approach

La reconnaissance visuelle de séquences de lettres implique un traitement orthographique qui peut être décomposé en trois phases activées en parallèle et de façon interactive : le traitement des traits visuels, le traitement des lettres et le traitement des séquences de lettres. L'influence des connaissances lexicales sur l'identification de lettres a souvent été mise en évidence par l'effet de supériorité du mot : une lettre étant mieux reconnue quand elle est présentée dans un mot que dans un non- mot ou isolément. L'un des objectifs de ce travail était de voir à quelle(s) phase(s) du traitement ces influences lexicales interviennent durant l'acquisition de la lecture. Pour ce faire, la technique des potentiels évoqués a été utilisée chez des enfants normo-lecteurs et dyslexiques dans une tâche d'identification de lettre présentée dans un mot ou un non-mot. Par ailleurs, il est admis par de nombreux auteurs que dans les langues alphabétiques et avec un sens de lecture de gauche à droite, les mots sont mieux reconnus quand ils sont fixés légèrement à gauche de leur centre. Cet effet de position optimale a également été étudié dans notre protocole afin de voir si les influences lexicales intervenaient quelque soit la position de la lettre dans le mot. Nos résultats comportementaux révèlent un effet de supériorité du mot uniquement chez les enfants normo-lecteurs reflétant l'intervention des connaissances lexicales. Nous postulons dès lors que les dyslexiques pourraient souffrir d'un déficit d'effet " top-down " lexical. Les analyses en fonction de la position ne montre pas l'effet de position optimale attendu. On observe des résultats similaires dans les deux groupes avec un gradient de performances diminuant de la première à la cinquième position qui pourrait s'expliquer par un traitement sériel et automatisé des stimuli de la gauche vers la droite et ce quelque soit le point de fixation. En potentiels évoqués, les premières différences entre mots et non-mots sont observées sur l'onde N2 reflétant le traitement lexical et elles s'observent pour les 2 groupes d’enfants. L'absence d'effet lexical sur l'onde N170 est en désaccord avec l'hypothèse d'une influence des représentations lexicales en mémoire sur l'identification de lettres à un niveau pré-lexical
Orthographic processes that take place during visual recognition of letter sequences can be dissociated into three different stages activated in an interactive and parallel manner : visual feature analysis, letter processing and letter sequence processing. The lexical influences on letter identification have often been observed with the well-known Word Superiority Effect : a letter is better identified when presented in words than in non-words or in isolation. One aim of this study was to understand which processing stages are influenced by lexical knowledge during reading acquisition. To do this, we performed an Event-Related Potential study with dyslexic children and typically achieving ones. The task consists in identifying a letter presented in a word or a non-word. Furthermore, it is well accepted that, in alphabetic and left-to-right languages, words are better identified when fixated slightly left of the center. Our task was designed in such a way that we were able to study this Optimal Viewing Position. The aim was to analyse if the lexical influences intervene in the same manner for all position in the word. Our behavioral results show a Word Superiority Effect only for typically achieving children suggesting influences of the lexical knowledge for them. We hypothesise that dyslexics present a deficit on these "top-down" lexical influences. Analyses based on the position do not show the Optimal Viewing Position expected. The results are similar in both groups with a diminution of the performance between the first and the last position. It suggests a serial and automatic processing of the stimuli from left to right whatever the fixation point. The firsts ERPs differences between words and non-words appears on the N2 reflecting the lexical processing and the same effect is shown in both groups. The lack of effect on the N170 is in disagreement with the hypothesis of lexical influences on letter identification at a pre-lexical level

Thesis (D.O.T.)--Boston University
Handwriting is one of the main activities in which children engage in during their learning years. Studies support the supposition that adequate handwriting is a necessary skill for a child to succeed in elementary school and beyond (Feder & Majnemer, 2003). It is estimated that 30% to 60% of a child's school day is spent completing written work (Marr, Windsor, & Cermak, 2001; McHale & Cermak, 1992). This written work is the primary means by which a teacher evaluates the child's learning. Studies have shown that legibility and handwriting speed influence a child's success in school (Graham, 2011). However, 10% to 30% of elementary school aged children have handwriting problems (Karlsdottir & Stefansson, 2002). Because children are required to submit written assignments in nearly every class beginning in the first grade, they typically fall behind academically when completion of these assignments becomes burdensome and time-consuming (Graham, 1992; Hammerschmidt & Sudsawad, 2004). As a result, learning is impaired, grades suffer, and the child may experience poor self-esteem (Engel-Yeger, Nagauker-Yanuv, & Rosenblum, 2009; Feder & Majnemer, 2007). Without formal intervention, children who have difficulty with handwriting in kindergarten through second grade continue to struggle as they progress through school and in many cases achieve less school success as the cognitive and motor demands increase (Graham, 2011). This author proposes it as essential that all preschool children be screened for indicators of possible future handwriting problems during their prekindergarten year. Unfortunately, screening proves to be a problem because at present there are few assessments that are appropriate for measuring handwriting skills in children under the age of five (Hoy, Egen, & Feder, 2011; van Hartingsveldt, De Groot, Aarts, & Nijhuis-Van Der Sanden, 2011). Furthermore, the handwriting assessments that do exist are not appropriate for use with preschool aged children. Occupational therapists (OT) try to circumvent this shortcoming by using a combination of several fine motor and visual motor tests to ensure a comprehensive assessment of the motor aspect of handwriting skills (Feder, Majnemer, & Synnes, 2000). This is both costly and time-consuming as the OT must have access to more than one assessment tool, and must allot the time to administer each one. The focus of this project is to develop a screening to measure the potential for future handwriting difficulty in elementary school by detecting deficits with the underlying motor performance factors necessary for adequate handwriting precision in preschool aged children. In addition, the author proposes the development of an intervention program specifically designed for preschool aged children. While there are intervention programs currently available to work with this age group, a comprehensive program that evaluates and provides intervention strategies for preschool aged children does not currently exist (Asher, 2006).

L'objectif de cette thèse est d'étudier le rôle de l'attention spatiale dans le traitement des lettres et des mots écrits. Très peu de recherches ont examiné l'implication des mécanismes attentionnels spatiaux dans l'étude des processus de traitement bas-niveau des mots et des lettres. Pour ce faire, nous avons combiné le paradigme d'amorçage masqué avec celui d'indiçage exogène. Nos résultats ont montré avec les stimuli lettres une modulation attentionnelle significative des effets de répétition qui n'a été observée qu'en présence d'un indice valide et avec des amorces reliées à la cible. Une démonstration supplémentaire de ce résultat a été obtenue à partir d'une étude comportementale manipulant l'inhibition de retour mais aussi à partir d'une étude électrophysiologique qui a révélé une composante P3 significative des potentiels évoqués modulée par la présence d'indices valides à l'emplacement des amorces reliées. Nous avons eu recours à une manipulation de l'excentricité avec les stimuli mots, pour une condition où l'amorce et la cible apparaissent au même endroit et pour une autre condition où la cible est toujours centrale et l'amorce a une position variable. Les résultats ont montré pour les deux conditions un avantage de l'hémi-champ visuel droit et des effets robustes d'amorçage limités essentiellement aux positions les plus fovéales dans la condition où la cible est toujours centrale. La présence de tels effets d'hémi-champ à des étapes précoces du traitement des mots constitue un résultat original. Ces résultats suggèrent que les effets d'amorçage peuvent au moins partiellement dépendre de la localisation des amorces. Le fait de répliquer ces mêmes effets avec les lettres vient confirmer l'intérêt d'une telle conclusion. Plus important encore est le fait que tous nos résultats ont été observés en l'absence de mouvements oculaires et de tout accès conscient des sujets aux amorces. L'ensemble de ces résultats a été interprété dans le cadre de l'approche de codage en bigrammes pour le traitement orthographique et une nouvelle version, incluant l'attention comme facteur modulateur des effets d'amorçage masqué avec répétition, a été suggérée.

The American Revolution brought with it a crisis of identification. The political divisions that fragmented American society did not distinguish adherents of the two sides in any outward way. Yet the new American governments had to identify their citizens; potential citizens themselves had to choose and prove their identities; and both sides of the war had to distinguish friend from foe. Subordinated groups who were notionally excluded from but deeply affected by the Revolutionary contest found in the same crisis new opportunity to seize control over their own identities. Those who claimed mastership over these groups struggled to maintain control amid civil war and revolution.

To meet this crisis, American and British authorities and "Americans" of all sorts employed paper and parchment instruments of identification, including passes, passports, commissions, loyalty certificates, and letters of introduction. These were largely familiar instruments, many embodying the hierarchical and coercive social world from which the Revolution sprang. Access or subjection to certain classes of instruments depended on individuals' social standing and reflected their unequal power over their own identities. But they were now deployed to meet new challenges. The increased demands for identification brought to Revolutionary Americans in general degrees of scrutiny and constraint traditional reserved for the unfree, while subordinated groups faced an intensification of the regimes designed to govern them. The struggles to define, enforce, and contest Revolutionary identities reveal the ways the notionally voluntarist, republican Revolution, undertaken in the name of consent and equality, was effected through regimes of identification both exclusive and coercive.

While studies of early American identity are now common, there has been little study of the history of identification or identification papers in early America. Historians of this period have employed instruments of identification as sources, but they have rarely considered them as subjects of analysis in themselves. This study of the Revolutionary crisis of identification, from 1774 to 1783, examines the ways that these instruments of identification were used to identify "Americans" in the face of this crisis, at home and abroad, and therefore how the new United States were constituted through the identification of individuals.

In Lactuca sativa, the dominant gene Tu confers resistance to infection by turnip mosaic virus (TuMV). Tu and Dm5/8, a gene for resistance to Bremia lactucae, are linked in L. sativa. The area surrounding Dm5/8 on the genetic map of L. sativa contains restriction fragment length polymorphism (RFLP) and random amplified polymorphic DNA (RAPD) markers. The orientation of Tu relative to Dm5/8 was not known. Locating Tu would indicate which markers are on the map of lettuce close to Tu. To locate Tu on the L. sativa genetic map, F$ sb3$ families from recombinant F$ sb2$ in the Dm5/8 area of a cross between TuMV-resistant (Cobbham Green) and susceptible (Calmar) cultivars were inoculated with TuMV and phenotyped for Tu by indirect enzyme-linked immunosorbent assay. Polyclonal antibodies for immunodetection were produced using turnip mosaic virus coat protein expressed in E. coli. Phenotypic ratios within F$ sb3$ families were used to determine individual F$ sb2$ genotypes for Tu. With these genotypes, Tu was located on the genetic map of L. sativa relative to data present for Dm5/8 and surrounding markers, between OPM18 and OPY13. Using bulked segregant analysis, bulks created for the Dm5/8 locus were screened for genetic polymorphisms by the RAPD technique. Five new RAPD markers, UBC346, UBC517, UBC563, UBC599, and UBC675 were found linked to Tu after mapping relative to F$ sb2$ genotypes for Tu and other RAPD markers. The resulting three-point mapping information indicates that Tu is flanked by two markers, OPM18/OPL08 and UBC346, at respective genetic distances of 0.4 and 0.7 cM.

The nucleotide sequence of a cloned RAPD DNA marker (OPI08) linked to a disease resistance gene in L. sativa (lettuce) revealed homology with the conserved domain of the reverse transcriptase of Ty3/gypsy retrotransposons. To further characterize the presence of Ty3/gypsy-like sequences in plants, sets of degenerate primers deduced from archetype retrotransposons were used for PCR amplification of a sequence domain characteristic of the reverse transcriptase and the integrase of Ty3/gypsy retrotransposons. The nucleotide sequence of two cloned DNA fragments of Z. mays (maize) and A. thaliana proved to be homologous with the conserved domains of the reverse transcriptase and the integrase of Ty3/gypsy retrotransposons. Southern blot analysis also demonstrated homology of the Z. mays clone to Lycopersicon (tomato) and L. sativa. This is the first report of Ty3/gypsy-like sequences in A. thaliana, and L. sativa. This research brings to six the number of plant species where this type of element has been reported, in contrast to the large number of plant Ty1/copia transposable elements described. It is not known whether these elements are actively transposing in plant genomes.

The chronology of the Late Bronze and Early Iron Age Near East is currently a topic of intense scholarly debate. The conventional/orthodox chronology for this period has been assembled over the past one-two centuries using information from King-lists, royal annals and administrative documents, primarily those from the Great Kingdoms of Egypt, Assyria and Babylonia. This major enterprise has resulted in what can best be described as an extremely complex but little understood jigsaw puzzle composed of a multiplicity of loosely connected data. I argue in my thesis that this conventional chronology is fundamentally wrong, and that Egyptian New Kingdom (Memphite) dates should be lowered by 200 years to match historical actuality. This chronological adjustment is achieved in two stages: first, the removal of precisely 85 years of absolute Assyrian chronology from between the reigns of Shalmaneser II and Ashur-dan II; and second, the downward displacement of Egyptian Memphite dates relative to LBA Assyrian chronology by a further 115 years. Moreover, I rely upon Kuhnian epistemology to structure this alternate chronology so as to make it methodologically superior to the conventional chronology in terms of historical accuracy, precision, consistency and testability.

L’effet d’encombrement, qui nous empêche d’identifier correctement un stimulus visuel lorsqu’il est entouré de flanqueurs, est omniprésent à travers une grande variété de classes de stimuli. L’excentricité du stimulus cible ainsi que la distance cible-flanqueur constituent des facteurs fondamentaux qui modulent l’effet d’encombrement. La similarité cible-flanqueur semble également contribuer à l’ampleur de l’effet d’encombrement, selon des données obtenues avec des stimuli non-linguistiques. La présente étude a examiné ces trois facteurs en conjonction avec le contenu en fréquences spatiales des stimuli, dans une tâche d’identification de lettres. Nous avons présenté des images filtrées de lettres à des sujets non-dyslexiques exempts de troubles neurologiques, tout en manipulant l’excentricité de la cible ainsi que la similarité cible-flanqueurs (selon des matrices de confusion pré-établies). Quatre types de filtrage de fréquences spatiales ont été utilisés : passe-bas, passe-haut, à large bande et mixte (i.e. élimination des fréquences moyennes, connues comme étant optimales pour l’identification de lettres). Ces conditions étaient appariées en termes d’énergie de contraste. Les sujets devaient identifier la lettre cible le plus rapidement possible en évitant de commettre une erreur. Les résultats démontrent que la similarité cible-flanqueur amplifie l’effet d’encombrement, i.e. l’effet conjoint de distance et d’excentricité. Ceci étend les connaissances sur l’impact de la similarité sur l’encombrement à l’identification visuelle de stimuli linguistiques. De plus, la magnitude de l’effet d’encombrement est plus grande avec le filtre passe-bas, suivit du filtre mixte, du filtre passe-haut et du filtre à large bande, avec différences significatives entre les conditions consécutives. Nous concluons que : 1- les fréquences spatiales moyennes offrent une protection optimale contre l’encombrement en identification de lettres; 2- lorsque les fréquences spatiales moyennes sont absentes du stimulus, les hautes fréquences protègent contre l’encombrement alors que les basses fréquences l’amplifient, probablement par l’entremise de leur impact opposé quant la disponibilité de l’information sur les caractéristiques distinctives des stimul.
Visual crowding, which impairs our ability to accurately identify a target stimulus when surrounded by flankers, is ubiquitous across a wide variety of stimulus classes. Target eccentricity and target-flanker distance constitute fundamental factors in crowding. Target-flanker similarity appears as another key factor based on findings obtained with non-linguistic stimuli. The present study investigated the impact of these factors in conjunction with spatial frequency content on single letter identification performance. We presented spatial frequency filtered letters to neurologically intact nondyslexic readers while manipulating target-flanker distance, target eccentricity and target-flanker similarity (metric based on published letter confusion matrices). Spatial frequency filtering conditions were broadband, low-pass, high-pass and hybrid (i.e. medium spatial frequencies, known as optimal for letter recognition, removed from the stimulus). These conditions were matched on overall contrast energy. Participants were required to identify the target letter as fast and as accurately as possible. The results show that high target-flanker similarity enhances crowding, i.e. the joint effects of distance and eccentricity. This extends past findings on the impact of similarity on crowding to the visual identification of linguistic materials. Most importantly, the magnitude of the crowding effect is greatest with low-pass filtering, followed by hybrids, high-pass, and broadband, with all pairwise contrasts significant. We conclude that: 1- medium spatial frequencies provide optimal protection from crowding in letter recognition; 2- when medium spatial frequencies are absent from the stimulus, low spatial frequencies magnify crowding and high spatial frequencies protect against it, most likely through their opposite impact on the availability of distinctive feature information.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1986.
Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 85-93).

Research in the area of early literacy has strongly supported instruction at the phonemic awareness level. In addition, a number of research articles have discussed the importance of involving parents in their children's education through home-based activities. This study examined the effects of a parent-training on early literacy skills in the areas of phonemic awareness and letter-identification. This study utilized a pre-experimental AB design. Thirty-nine kindergarten children from the northeast were administered early literacy measures (Dynamic Indicators of Basic Early Literacy Skills - DIBELS) ten times during both the base-line phase and treatment phases. Twenty children comprised the treatment group, and their parents participated in five training sessions and 10 weeks of interactive book reading and practice and instruction of specific skills with their children. Results were positive and significant for the three early literacy measures, (Onset Fluency, Letter-Naming Fluency, and Phoneme Segmentation). In addition, treatment integrity and acceptability were measured. Limitations to the study, implications for education and future research are also discussed.

The effects of parent-delivered instruction on children's phonemic awareness were investigated. Participants were thirty-eight parents and their pre-school children. The purpose of this study was to: (1) investigate whether parents could successfully teach phoneme identification skills to preschool children; (2) assess whether the effects of parent-delivered instruction on phonemic awareness and the alphabetic principle could be independent of pretest letter knowledge, child vocabulary and cognitive ability, and SES; (3) determine whether training would generalize to recognition of untrained phonemes; and (4) assess parent satisfaction with the training and instructional program. Children were matched based on vocabulary scores. This measure was also a proxy for SES (Hart & Risley, 1995). Children were then randomly assigned to either treatment or control groups. In addition, pretest letter knowledge was assessed using experimental measures designed by Byrne and Fielding-Barnsley (1991). Parents taught their child to identify initial and ending phonemes and letter-sounds based on the early literacy program Sound Foundations (Byrne & Fielding-Barnsley, 1991), with lesson scripts based on explicit, direct instruction techniques (Kameenui & Carnine,1998; Swanson, Hoskyn & Lee, 1999). The duration of the program was 7 weeks. Children were required to find poster pictures that began or ended with the target sound and to color pictures with the target sound. Dynamic Indicators of Basic Early Literacy Skills (DIBELS) (Good & Kaminski, 2002) were used to measure Initial Sound Fluency and Letter Naming Fluency. Experimental measures of ending sound fluency, initial phoneme transfer and ending phoneme transfer were also used to measure outcomes. A survey was used to obtain social validity data regarding parent satisfaction with the program. Results indicated that: (a) there was a large, albeit insignificant effect for parent training on children's initial sound fluency (d = 1.1, p < .006); (b) parent training was not predictive of letter naming fluency (p =.07); (c) there were no significant differences on measures of phoneme transfer; and (d) pretest letter knowledge was predictive of outcomes on letter naming fluency (p < .01). Parents reported a high degree of satisfaction with training. The discussion focuses on future research on early literacy instruction and parent-delivered instruction.

Early reading instruction and identification of learners with reading problems prevent reading difficulties in the Intermediate Phase. The specific aim of this study is to explore the role of the Intermediate Phase educator to assess the learners’ reading skills by using observation and assessment activities, in order to identify learners with reading problems. The literature study on reading activities explored the letters of the alphabet, phonemic awareness, spelling, word- recognition, assessment and word-knowledge. The qualitative research was conducted empirically in the form of a case study of one learner from the South African public primary school based in Ikageng location, Potchefstroom. The role of the Intermediate Phase educator is to develop and administer the reading activities, observe a learner when he or she recites; writes and identifies the letters of the alphabet; segment words to show his or her phonological awareness skill; spell words in the dictation test including any written activity; and reads aloud the single written words to test his or her word recognition ability. The themes that emerged from the empirical study are as follows: difficulty in sequencing written letters of the alphabet, inability to segment words, spelling problems and word recognition problems. The study indicated that the participant’s reading problems are based on an inability to decode single words.
Psychology of Education
M. Ed. (Educational Psychology)

Text in English
The purpose of this dissertation was to establish the rhetorical function of Romans 7 within the context of Romans 5-8. Chapter 1 involved a survey of the problem that led to the investigation and a discussion of a number of approaches offered as an interpretation for understanding Romans 7. Chapter 2 centred on an investigation into the nature of Paul's audience in Rome. Chapter 3 investigated the purpose of the letter as a help to understanding the rhetorical function of Romans 7. Chapter 4 dealt with the rhetorical function of Romans 7. The causa underlying Paul's rhetoric in Romans 7 was a tendency among Gentile Christians to want to return to the law. Paul set out strongly to counter this tendency because it was incompatible with their position in Christ and would foil his plans in respect of the Gentile Christians in Rome and of the Gospel to the West.
Biblical & Ancient Studies
M.A. (Biblical Studies)