951 resultados para Acquisition of oral microflora
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Middle ear infections (acute otitis media, AOM) are among the most common infectious diseases in childhood, their incidence being greatest at the age of 6–12 months. Approximately 10–30% of children undergo repetitive periods of AOM, referred to as recurrent acute otitis media (RAOM). Middle ear fluid during an AOM episode causes, on average, 20–30 dB of hearing loss lasting from a few days to as much as a couple of months. It is well known that even a mild permanent hearing loss has an effect on language development but so far there is no consensus regarding the consequences of RAOM on childhood language acquisition. The results of studies on middle ear infections and language development have been partly discrepant and the exact effects of RAOM on the developing central auditory nervous system are as yet unknown. This thesis aims to examine central auditory processing and speech production among 2-year-old children with RAOM. Event-related potentials (ERPs) extracted from electroencephalography can be used to objectively investigate the functioning of the central auditory nervous system. For the first time this thesis has utilized auditory ERPs to study sound encoding and preattentive auditory discrimination of speech stimuli, and neural mechanisms of involuntary auditory attention in children with RAOM. Furthermore, the level of phonological development was studied by investigating the number and the quality of consonants produced by these children. Acquisition of consonant phonemes, which are harder to hear than vowels, is a good indicator of the ability to form accurate memory representations of ambient language and has not been studied previously in Finnish-speaking children with RAOM. The results showed that the cortical sound encoding was intact but the preattentive auditory discrimination of multiple speech sound features was atypical in those children with RAOM. Furthermore, their neural mechanisms of auditory attention differed from those of their peers, thus indicating that children with RAOM are atypically sensitive to novel but meaningless sounds. The children with RAOM also produced fewer consonants than their controls. Noticeably, they had a delay in the acquisition of word-medial consonants and the Finnish phoneme /s/, which is acoustically challenging to perceive compared to the other Finnish phonemes. The findings indicate the immaturity of central auditory processing in the children with RAOM, and this might also emerge in speech production. This thesis also showed that the effects of RAOM on central auditory processing are long-lasting because the children had healthy ears at the time of the study. An effective neural network for speech sound processing is a basic requisite of language acquisition, and RAOM in early childhood should be considered as a risk factor for language development.
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One group of 12 non learning disabled students and two groups of 12 learning disabled students between the ges of 10 and 12 were measured on implicit and explicit knowledge cquisition. Students in each group implicitly cquired knowledge bout I of 2 vocabulary rules. The vocabulary rules governed the pronunciation of 2 types of pseudowords. After completing the implicit acquisition phase, all groups were administered a test of implicit knowledge. The non learning disabled group and I learning disabled group were then asked to verbalize the knowledge acquired during the initial phase. This was a test of explicit knowledge. All 3 groups were then given a postlest of implicit knowledge. This tcst was a measure of the effectiveness of the employment of the verbalization technique. Results indicate that implicit knowledge capabilities for both the learning disabled and non learning disabled groups were intact. However. there were significant differences between groups on explicit knowledge capabilities. This led to the conclusion that implicit functions show little individual differences, and that explicit functions are affected by ability difference. Furthermore, the employment of the verbalization technique significantly increased POStlest scores for learning disabled students. This suggested that the use of metacognitive techniques was a beneficial learning tool for learning disabled students.
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This study examined the effectiveness of context on the acquisition of new vocabulary for good and poor readers. Twentyeight Grade Three children, fourteen good readers and fourteen poor readers, took part in a word-learning task within three conditions: (1) strong sentence context, (2) weak sentence context, and (3) list condition. The primary hypothesis was that poor readers would show less learning in the list condition than good readers and that there would be no difference in the amount of learning in the sentence conditions. Results revealed that: (a) Words are read faster in sentence contexts than in 1 ist contexts; (b) more learning or greater improvement in performance occurs in list contexts and weak sentence contexts as opposed to strong sentence contexts; and (c) that most of these differences can be attributed to the build-up of meaning in sentences. Results indicated that good and poor readers learned more about words in all three condi tions. More learning and greater performance occurred in the list condition as opposed to the two sentence conditions for both subject groups. However, the poor readers learned significantly more about words in both the list condition and the weak sentence condition than the good readers.
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A class of twenty-two grade one children was tested to determine their reading levels using the Stanford Diagnostic Reading Achievement Test. Based on these results and teacher input the students were paired according to reading ability. The students ages ranged from six years four months to seven years four months at the commencement of the study. Eleven children were assigned to the language experience group and their partners became the text group. Each member of the language experience group generated a list of eight to be learned words. The treatment consisted of exposing the student to a given word three times per session for ten sessions, over a period of five days. The dependent variables consisted of word identification speed, word identification accuracy, and word recognition accuracy. Each member of the text group followed the same procedure using his/her partner's list of words. Upon completion of this training, the entire process was repeated with members of the text group from the first part becoming members of the language experience group and vice versa. The results suggest that generally speaking language experience words are identified faster than text words but that there is no difference in the rate at which these words are learned. Language experience words may be identified faster because the auditory-semantic information is more readily available in them than in text words. The rate of learning in both types of words, however, may be dictated by the orthography of the to be learned word.
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Twenty-six sedentary, college-aged females were matched and randomly assigned to one of two groups. The massed group (n=13) completed 15 maximal isometric elbow flexion strength trials in one session, while the distributed group (n=13) performed five such contractions on three successive days. After a two-week and three month rest interval, both groups returned to perfonn another five maximal isometric elbow flexion strength trials to assess retention of any potential strength gains. Elbow flexion torque and surface electromyography (SEMG) of the biceps and triceps were monitored concurrently. There was a significant (P < 0.05) increase in strength in both groups from block one (first five contractions) to block four (first retest) and from block one to block five (second retest). Both groups exhibited a similar linear increasing (P < 0.05) trend in biceps root-mean-square (RMS) SEMG amplitude. A significant (P < 0.05) decrease in triceps RMS SEMG amplitude was found between block one and block four for the distributed group. However, a significant (P < 0.05) increase was then found between block one and five for the massed group, and between blocks four and five for distributed group. These results suggest that there is flexibility in resistive exercise schedules. An increase in neural drive to the agonist muscle continued throughout testing. This was accompanied by a reduction in antagonist co activation that was a short-tenn (two weeks) training effect, dissipated over the longer rest interval (three months).
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Recent studies have shown that providing learners Knowledge of Results (KR) after “good trials” rather than “poor trials” is superior for learning. The present study examined whether requiring participants to estimate their three best or three worst trials in a series of six trial blocks before receiving KR would prove superior to learning compared to not estimating their performance. Participants were required to push and release a slide along a confined pathway using their non-dominant hand to a target distance (133cm). The retention and transfer data suggest those participants who received KR after good trials demonstrated superior learning and performance estimations compared to those receiving KR after poor trials. The results of the present experiment offer an important theoretical extension in our understanding of the role of KR content and performance estimation on motor skill learning.
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Les nanoparticules (NPs) de polymère ont montré des résultats prometteurs pour leur utilisation comme système de transport de médicaments pour une libération contrôlée du médicament, ainsi que pour du ciblage. La biodisponibilité des médicaments administrés oralement pourrait être limitée par un processus de sécrétion intestinale, qui pourrait par la suite être concilié par la glycoprotéine P (P-gp). La dispersion de la Famotidine (modèle de médicament) à l’intérieur des nanoparticules (NPs) pegylées a été évaluée afin d’augmenter la biodisponibilité avec du polyéthylène glycol (PEG), qui est connu comme un inhibiteur de P-gp. L’hypothèse de cette étude est que l’encapsulation de la Famotidine (un substrat de P-gp) à l’intérieur des NPs préparées à partir de PEG-g-PLA pourrait inhiber la fonction P-gp. La première partie de cette étude avait pour but de synthétiser quatre copolymères de PEG greffés sur un acide polylactide (PLA) et sur un squelette de polymère (PLA-g-PEG), avec des ratios de 1% et 5% (ratio molaire de PEG vs acide lactique monomère) de soit 750, soit 2000 Da de masse moléculaire. Ces polymères ont été employés afin de préparer des NPs chargés de Famotidine qui possède une faible perméabilité et une solubilité aqueuse relativement basse. Les NPs préparées ont été analysées pour leur principaux paramètres physicochimiques tels que la taille et la distribution de la taille, la charge de surface (Potentiel Zeta), la morphologie, l’efficacité d’encapsulation, le pourcentage résiduel en alcool polyvinylique (PVA) adsorbé à la surface des NPs, les propriétés thermiques, la structure cristalline et la libération du médicament. De même, les formules de NPs ont été testées in vitro sur des cellules CaCo-2 afin dʼévaluer la perméabilité bidirectionnelle de la Famotidine. Généralement, les NPs préparées à partir de polymères greffés PLA-g-5%PEG ont montré une augmentation de la perméabilité du médicament, ce par l’inhibition de l’efflux de P-gp de la Famotidine dans le modèle CaCo-2 in vitro. Les résultats ont montré une baisse significative de la sécrétion de la Famotidine de la membrane basolatéral à apical lorsque la Famotidine était encapsulée dans des NPs préparées à partir de greffes de 5% PEG de 750 ou 2000 Da, de même que pour d’autres combinaisons de mélanges physiques contenant du PEG5%. La deuxième partie de cette étude est à propos de ces NPs chargées qui démontrent des résultats prometteurs en termes de perméabilité et d’inhibition d’efflux de P-gp, et qui ont été choises pour développer une forme orale solide. La granulation sèche a été employée pour densifier les NPs, afin de développer des comprimés des deux formules sélectionnées de NPs. Les comprimés à base de NPs ont démontré un temps de désintégration rapide (moins d’une minute) et une libération similaire à la Famotidine trouvée sur le marché. Les résultats de l’étude du transport de comprimés à base de NPs étaient cohérents avec les résultats des formules de NPs en termes d’inhibition de P-gp, ce qui explique pourquoi le processus de fabrication du comprimé n’a pas eu d’effet sur les NPs. Mis ensemble, ces résultats montrent que l’encapsulation dans une NP de polymère pegylé pourrait être une stratégie prometteuse pour l’amélioration de la biodisponibilité des substrats de P-gp.
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Biophotonics Laboratory,Centre for Earth Science Studies
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We present an unsupervised learning algorithm that acquires a natural-language lexicon from raw speech. The algorithm is based on the optimal encoding of symbol sequences in an MDL framework, and uses a hierarchical representation of language that overcomes many of the problems that have stymied previous grammar-induction procedures. The forward mapping from symbol sequences to the speech stream is modeled using features based on articulatory gestures. We present results on the acquisition of lexicons and language models from raw speech, text, and phonetic transcripts, and demonstrate that our algorithm compares very favorably to other reported results with respect to segmentation performance and statistical efficiency.
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En este trabajo se describe la naturaleza y secuencia de adquisición de las preguntas interrogativas parciales en niños de habla catalana y/o castellana dentro de un marco de análisis según el cual la adquisición de las estructuras lingüísticas se construye gradualmente desde estructuras concretas hasta estructuras más abstractas. La muestra utilizada se compone de 10 niños y niñas procedentes de corpus longitudinales cuyas edades van de los 17 meses a los 3 años. El análisis se ha realizado atendiendo a la estructura sintáctica de la oración, los errores, los pronombres y adverbios interrogativos, y la tipología verbal. Los resultados muestran que la secuencia de adquisición pasa por un momento inicial caracterizado por producciones estereotipadas o fórmulas, durante el cual sólo aparecen algunas partículas interrogativas en estructuras muy concretas. Posteriormente la interrogación aparece con otros pronombres y adverbios y se diversifica a otros verbos, además, no se observan errores en la construcción sintáctica. Estos resultados suponen un hecho diferencial respecto de estudios previos en lengua inglesa
Resumo:
Objective: This study offers a description of the kinds of linguistic aids offered by adults while giving explanations to young children about different issues. During the midst of these conversations children have several opportunities to learn, not only from objects and events, but also from the utterances used to refer to them, learning how realities are named after, and in many cases, how to participate in them. Methodology: Through the analysis of eleven minutes of interaction between young child and his maternal grandparents. Results: Adults offers young child different discursive ways for helping him to add information, organize and clarify the topic that he is talking about. Conclusions: The results allow to identify different ways that the adults use for helping young child to improve his explanations.
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El artículo es un intento de dar un nuevo enfoque a la controversia sobre la universalidad de la 'Binding Theory', principalmente en los principios A y B. Los autores presentan evidencias no solo desde la lingüística sincrónica y diacrónica, sino tambia desde resultados obtenidos en experimentos en el campo de la adquisición del lenguaje, que permiten concluir que aunque estos principios sintácticos existen, no son universales.
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Guía práctica para diseñar y usar tests orales de habilidad lingüística, dirigido a profesores, examinadores, diseñadores de cursos y planificadores de educación. El libro presenta las etapas en que debe desarrollarse el programa de evaluación de las habilidades lingüísticas, con ejemplos prácticos y temas de debate que pueden surgir en cada etapa, y considera la evaluación de las habilidades de expresión oral como una parte integral del programa de aprendizaje de cualquier idioma. Incluye una descripción de diferentes tipos de tests y su idoneidad según los objetivos y recursos, cincuenta técnicas comentadas de evaluación oral, integra el sistema de puntuación en el proceso de diseño de tests y proporciona sugerencias para supervisarlos y mejorarlos una vez que se están utilizando.
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Resumen basado en el de la publicaci??n