This study examined the unique contributions of morphological awareness and phonological recoding to word decoding, reading comprehension, and reading vocabulary for 197 Spanish-speaking English language learners enrolled in the fifth grade. The study also explored the contribution of phonological recoding, measured by accuracy on a pseudo-word decoding task, to the prediction of the same components of reading achievement. Specifically the study explored whether the contribution of phonological recoding changed when morphological awareness and oral vocabulary (a mediator of reading achievement) were added as predictors. To examine unique contributions, morphological awareness was separated from phonological and orthographic confounds present in opaque morphological relationships by using structural equation modeling to construct a latent variable stemming from the shared variance of four morphological tasks with different levels of morphological transparency, and therefore different phonological and orthographic processing demands. A latent variable of phonological recoding was also created. Findings indicated that when controlling for phonological recoding, morphological awareness made a significant and meaningful contribution to passage comprehension and reading vocabulary, but not word decoding with oral vocabulary acting as a significant mediator of this relationship. The study also found that phonological recoding was a significant predictor of each reading outcome when morphological awareness was not included as a predictor, but only significantly predicted word reading when controlling for morphological awareness. Significance of these findings to research and the need for additional morphological instruction within educational settings are discussed.

Today’s communication network is changing rapidly and radically. Demand for low latency, high reliability and low energy consumption increases as well the variety of characteristics of the connected devices. It is also expected that the number of connected devices will be massive in coming years. Some devices will be connected to the new generation base stations directly, while some of them will be connected through other devices via multi-hops. Reliable communication between these massive devices can be done via re-transmission, repetition of packets several times or via Forward Error Correction (FEC). In re-transmission method, when packets are negatively acknowledged or the sender’s acknowledgment timer expires, packets are re-transmitted. In repetition method, every packet can be send several times. Both aforementioned methods can cause a huge delay, particularly, in multi-hop network. On the contrary of these methods, FEC methods are preferred for low latency applications. Source information are transmitted together with redundant information. Hence, the number of transmissions are reduced comparing to the methods mentioned above. Random Linear Network Coding (RLNC) is a packet level erasure correcting codes which aims to reduce latency. Specifically, source packets are combined and these combinations or coded packets are sent to the destination. Lost packets do no need to be re-sent since another coded packet can be substituted to the lost coded packet. Hence, the feedback mechanism and re-sending process becomes unnecessary. There are many variations of RLNC. One variation is called sliding window RLNC which apples FEC mechanism. This coding scheme achieves low latency via interleaved coded packets in between source packets. Another variation of the RLNC is Fulcrum, which is a versatile code. Fulcrum provides three different decoding options. Received coded packets can be decoded with low, high or middle complexity. This is a very important feature since connected devices will have different computation capabilities and proving a versatile code will allow them flexibility. Although the aforementioned coding schemes are well suited to error prone network, there are still remaining challenges need to be studied. For instance, Fulcrum RLNC has high encoding and decoding complexity which increase the computation time and energy consumption. Moreover, although original Fulcrum RLNC strengths the reliability, it needs to be improved for low latency applications. Another remaining challenges is that recoding strategy of RLNC is not optimal for low latency. Allowing the intermediate nodes to combine received packets is referred as recoding. As described earlier, data packets will pass many hops until they reach destination. Therefore, compute-and-forward paradigm will be preferred rather than store-and-forward. Although recoding capability of RLNC differs it from other coding schemes (Raptor, LT), the conventional way of recoding is not efficient for low latency. Hence, the aim of this thesis is to address the aforementioned remaining challenges. One way to address the remaining challenges is to employ sparsity. In other words, a few source packets can be combined rather than a large set of source packets to generate coded packets. Particularly, a dynamic sparse mechanism is proposed to vary the number of combined source packets during the encoding without a signaling between sender and receiver for Fulcrum RLNC to speed up encoding and decoding process without increasing overhead amount. Then, two different sliding window schemes were integrated into Fulcrum RLNC to make Fulcrum RLNC gain the low latency property. Sending source packets systematically and then spreading sparse coded packets in between systematic source packets can be referred as systematic sparsity. Moreover, different sparse and systematic recoding strategies have been proposed in this thesis to lower the delay and computation time at the intermediate nodes and destination. Finally, one of the proposed recoding strategy has been applied to the vehicle platooning scenario to increase reliability. All proposed coding schemes were analyzed and performed on KODO which is well known network coding library.

This thesis describes experiments investigating the translational recoding activities and the novel dual signalling properties of eukaryotic ribosome skipping 2A sequences. Over twenty years ago, the 19 amino acid 2A region of a Picornavirus; namely, Foot-and-Mouth Disease Virus (FMDV) polypeptide was shown to possess apparent “self-cleaving” abilities, cutting at its own C-terminus during translation (Ryan et al., 1991). Active FMDV 2A-like sequences were subsequently found in a number of related viruses (Luke et al., 2008), with several now utilised as essential biotechnology multi-gene transfer tools (Luke et al., 2010b). Then, in 2006, eukaryotic 2A-like sequences were identified from trypanosome non-LTR sequences. These were found to be functional in vitro (Heras et al., 2006). I have been able to identify over 400 putative eukaryotic 2A-like sequences through searching the freely available online proteomic and genomic databases. Data is presented to show that these 2As were encoded in frame with non-LTRs, or metabolic, or immune function genes, from a wide range of eukaryotic organisms; but I could not discern any obvious phylogenetic distribution for 2A. I have discovered that the majority of eukaryotic 2A sequences tested can mediate ribosome skipping in vitro. Modelling in silico indicated that active 2A-like sequences possessed the propensity to form a central alpha-helical region, whereas the models suggested that inactive 2A-like sequences would be essentially unstructured. I also report that some of these eukaryotic 2A peptides constitute a novel form of dual protein targeting as they play a dual role as exocytic pathway signal peptides mediating extracellular protein trafficking. I have shown that this protein trafficking ability is evolutionarily conserved, with an echinoderm sequence able to direct protein targeting in both plant and mammalian cells. I therefore propose that these novel eukaryotic 2A sequences could potentially become extremely valuable in biotechnological engineering.

La synthèse des sélénoprotéines fait appel à un mécanisme de recodage traductionnel d’un codon UGASec. Chez les mammifères, ce processus est conditionné par le recrutement de facteurs spécialisés dans la région 3’UTR des ARNm de sélénoprotéines, au niveau d’une tige-boucle appelée SECIS. Lors de ma thèse, nous avons montré que certains ARNm de sélénoprotéines possèdent une coiffe hyperméthylée m32,2,7G à leur extrémité 5’, à la manière d’ARN non-codants, et ne sont pas reconnus efficacement par le facteur canonique d’initiation de la traduction eIF4E. Nous avons déterminé le mécanisme de biogenèse de cette coiffe qui fait appel à la Triméthyl-guanosine synthase, et avons montré que les ARNm de sélénoprotéines coiffés m32,2,7G sont traduits in vivo. Par ailleurs, nos résultats indiquent que l’initiation de la traduction des ARNm de sélénoprotéines suit un mécanisme atypique qui ferait intervenir des éléments structuraux de l’ARNm, la région 3’UTR et une GTPase encore inconnue. / Selenoprotein synthesis requires co-translational recoding of in-frame UGA codons. In mammals, this process is governed by the recruitment of dedicated factors on a hairpin structure, called SECIS, in the 3’UTR of selenoprotein mRNAs. During my PhD, we showed that several selenoprotein mRNAs bear a hypermethylated m32,2,7G cap and undergo a similar 5’ end maturation pathway than non-coding RNAs. This cap biogenesis mechanism involves the enzyme Trimethyl-guanosine synthase, m32,2,7G capped selenoprotein mRNAs are not efficiently recognized by the canonical translation initiation factor eIF4E but are translated in vivo. Furthermore, our results suggest the existence of an atypical mechanism of translation initiation for selenoprotein mRNAs. This process involves structural RNA determinants, the 3’UTR region and a GTPase that remains to be identified.

No description available.

La synthèse des protéines est un mécanisme central de la vie cellulaire dont la compré-hension est un enjeu pour la recherche biomédicale. Des phénomènes comme les erreurs programméesde la traduction eucaryote ou l’initiation par des structures IRES virales sont impliqués dans les processusde réplication de virus et de bactéries. Mieux appréhender ces processus est une étape essentiellepour aboutir au développement d’approches thérapeutiques innovantes. Les études en molécule uniquepermettent d’observer chaque système réactionnel individuellement et donnent accès à des évènementsasynchrones difficilement observables en mesure d’ensemble, tels la traduction de protéines.Ce manuscrit de thèse présente une approche d’étude de la traduction par un ribosome eucaryote(mammifère) en molécule unique. Nous observons les systèmes traductionnels grâce à des marqueursfluorescents liés à des oligonucléotides pouvant s’hybrider sur les séquences d’ARN messagers traduites.L’observation de ces marqueurs est faite par microscopie de fluorescence en réflexion totale (TIRFM),les ARNm étant accrochés à la surface de l’échantillon. En lisant l’ARNm, le ribosome détache lesmarqueurs, et leurs instants de départ nous permettent de remonter à la dynamique de traductionde ribosomes individuels. Cette méthode permet d’obtenir des données cinétiques statistiques surun grand nombre de systèmes traductionnels en parallèle pouvant alors être ajustées par des lois deprobabilité. Partant de ce principe, mes travaux de thèse ont eu pour objectif d’étendre nos expériencesà une nouvelle problématique biologique : l’étude des évènements non canoniques de la traductioneucaryote. Pour cela nous avons apporté les modifications et les optimisations nécessaires au dispositifet au protocole expérimental pour l’adapter à ces nouveaux enjeux.Nos mesures de la cinétique in vitro de l’élongation eucaryote ont mis à jour un délai dû à uneinitiation non-canonique. En effet, nous réalisons le recrutement du ribosome par l’ARNm grâce àune structure virale de type IRES. Dans nos conditions d’expérience, l’incorporation d’un acide aminéprend environ une seconde tandis que cette structure induit un retard à la traduction de plusieursdizaines de secondes. Nous avons réalisé une étude comparative de plusieurs de ces structures viraleset avons montré que le délai mesuré était une caractérisitique conservée dans le cadre de l’initiation noncanonique. Ce résultat ouvre des perspectives d’études cinétiques tant pour approfondir nos conclusionssur les IRES que pour aborder d’autres évènements non canoniques tel que le décalage de la phase delecture ou le franchissement du codon stop. / The synthesis of proteins is a central mechanism of cellular life whose understandingis an issue for biomedical research. Phenomena such as programmed errors of eukaryotic translation orinitiation by viral IRES structures are involved in virus and bacterial replication processes. A Betterunderstanding of these processes is an essential step towards the development of innovative therapeuticapproaches.Single molecule studies allow each reaction system to be observed individually and give accessto asynchronous events, such as protein translation, that are difficult to observe in overall measurements.This phD manuscript presents a single molecule approach to study translation by a eukaryotic(mammalian) ribosome.We observe the translational systems thanks to fluorescent primers linked to oligonucleotides thatare hybridized to the translated mRNA sequences. These markers are observed by Total InternalReflection Fuorescence Microscopy (TIRFM) ; with the mRNAs attached to the sample surface. Whilereading the mRNA, the ribosome detaches the primers, and their instants of departure give us access tothe translation dynamics of individual ribosomes. This method makes it possible to obtain statisticalkinetic data on a large number of parallel translational systems, which can then be fitted by probabilitylaws. On the basis of this principle, my phD work aimed at extending our experiments to a newbiological issue : the study of non-canonical events in eukaryotic translation. To this end, we havemade the modifications and optimizations necessary for the set-up and the experimental protocol toadapt them to these new challenges.Our measurements of the in vitro kinetics of eukaryotic elongation have revealed a delay due tonon-canonical initiation. Indeed, the ribosome are recruited on the mRNA thanks to a viral, IREStype structure. Under our experimental conditions, the incorporation of an amino acid takes aboutone second while this structure induces a translation delay of several tens of seconds. We carried outa comparative study of several of these viral structures and showed that the measured delay was acharacteristic preserved in the framework of the non-canonical initiation. This result opens up prospectsfor kinetic studies both to deepen our conclusions on IRES and to address other non-canonical eventssuch as programmed frameshifting or STOP codon readthrough.

xviii, 193 p. / Learning to read and successfully decode words is complex, requiring the integration of critical component skills such as phonological awareness, alphabetic understanding, and phonological recoding. As foundational skills required for reading with automaticity, researchers recommend that explicit instruction of these skills begin early, particularly for students at risk. One commonly used measure to examine students' alphabetic understanding and phonological recoding skills is DIBELS Nonsense Word Fluency (NWF), a pseudo-word reading measure composed of vowel-consonant and consonant-vowel-consonant words. One purpose of this study was to examine the effects of school-level and individual student-level predictors on students' overall performance on NWF in the spring of grade 1 as evidenced by their total Correct Letter Sounds (CLS) and Words Read as Whole Units Correctly (WRWUC) scores. A series of hierarchical linear models were estimated to investigate the contributions of three student-level predictors (English Learner status, fall of grade 1 Phoneme Segmentation Fluency raw scores, and fall of grade 1 NWF scores) and two school-level predictors (percentage of students eligible for free and reduced lunch and percentage of incoming at-risk kindergarteners) in explaining the variance observed in NWF scores A second purpose was to estimate the item difficulties of the first 20 pseudo-words for comparability of difficulty, controlling for student-level covariates. A series of hierarchical generalized linear models were estimated to investigate the contribution of student-level predictors while controlling for school effects. Participants were 1,111 first grade students enrolled in 14 elementary schools participating in the Oregon Reading First initiative. Results indicated that fall of grade 1 NWF raw and quadratic scores were the only statistically significant student-level predictors of CLS and WRWUC scores in the fully specified Level 1 model. The relation between school-level predictors and spring of grade 1 NWF performance complicated interpretation, but both school-level predictors were also significant. Additionally, results of the item difficulty estimates reveal significant student-level effects on item difficulties, providing evidence that item parameters are not equal for the first 20 pseudo-words on DIBELS NWF. The effects were particularly strong for English Learners. Implications for practice and directions for future research are discussed. / Committee in charge: Dr. Paul Yovanoff, Chair; Dr. Gerald Tindal, Member; Dr. Akihito Kamata, Member; Dr. Elizabeth Harn, Outside Member

Made available in DSpace on 2015-04-11T13:57:04Z (GMT). No. of bitstreams: 1 anielly.pdf: 6476251 bytes, checksum: ca7f5065e8e3f571765996af8796ab58 (MD5) Previous issue date: 2012-11-01 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Comics (comics), formerly associated with the print media today are blogs, websites, creating a specific new product (webcomics). Under the bias of semiotic, we understand how comics have changed when transmuting the printed media to digital. We used the concepts of the semiotics of culture, which suggested the dynamics of the characters studied in culture. In this sense, the comics are objects of codes and are manifested as cultural texts, and the operation is taking place in the relationship of these codes. In view of the semiotic concepts, analyze semiosis entertainment systems (comics), occurring through the interaction of the different languages - film, photography, cartoon, painting - and the relationship with the digital system (Internet). Because it is an issue that occurs at the intersection of communication and semiotics, the study takes a transdisciplinary vision and wants to correlate the existing features in both in order to understand the changes generated in the comics in the Internet environment. We start from the assumption that the internet environment is changing the language of comics, thus we analyzed five sites that publish comics, and were selected because they exhibited characteristics to prove our hypothesis. We make an observation script that was completed at the time were held data collection during the period August-September 2011, according to the dates that were posted the comics. Thus, this research is relevant because the main focus is the language of comics produced from contact with other languages of cyberspace, checking the modeling systems in this environment. It is believed that the research will contribute to the role of comic culture. / As Histórias em Quadrinhos (HQs), antigamente vinculadas apenas nos meios impressos hoje estão em blogs, sites específicos gerando um novo produto (webcomics). Sob o viés semiótico, buscamos compreender como as histórias em quadrinhos se modificaram ao se transmutarem do suporte impresso para o digital. Para isso, recorremos aos conceitos proposto pela Semiótica da Cultura, que investiga a dinâmica dos signos na cultura. Nesse sentido, as histórias em quadrinhos tornam-se objetos por serem compostas por códigos e se manifestam como textos culturais, sendo que o seu funcionamento se dá perante a relação de sistemas culturais de alta complexidade. Diante dos conceitos semióticos, analisamos a semiose dos sistemas do entretenimento (histórias em quadrinhos), ocorridas através da interação das diversas linguagens do cinema, fotografia, desenho animado, pintura e a relação com o sistema digital (internet). Por se tratar de um tema que ocorre na intersecção das áreas da comunicação e da semiótica, a pesquisa adota uma visão transdisciplinar e busca correlacionar os aspectos existentes em ambas para compreender a semiose das HQs no ambiente da internet. Partimos da hipótese que este ambiente modifica a linguagem das histórias em quadrinhos, assim, analisamos cinco sites que publicam HQs, sendo que foram escolhidos por apresentarem características que demonstram nossa hipótese. Elaboramos um roteiro de observação que foi preenchido no momento em que foram realizadas as coletas de dados, no período de agosto a setembro de 2011, obedecendo as datas em que foram postadas as HQs. Dessa maneira, a presente pesquisa torna-se relevante uma vez que o foco principal é a linguagem das HQs produzidas a partir do contato com as demais linguagens do ciberespaço, verificando os sistemas modelizantes presentes nesse ambiente. Acredita-se que a pesquisa contribuirá para reforçar o papel das histórias em quadrinhos na cultura.

Statistical data, such as in the form of microdata, is used by different organisations as a basis for creating knowledge to assist in their planning and decision-making activities. However, before microdata can be made available for analysis, it needs to be anonymised in order to protect the privacy of the individuals whose data is released. The protection of privacy requires us to hide or obscure the released data. On the other hand, making data useful for its users implies that we should provide data that is accurate, complete and precise. Ideally, we should maximise both the level of privacy and the level of information utility of a released microdata set. However, as we increase the level of privacy, the level of information utility decreases. Without guidelines to guide the selection of the optimum levels of privacy and information utility, it is difficult to determine the optimum balance between the two goals. The objective and constraints of this optimisation problem can be captured naturally with concepts from Economic Price Theory. In this thesis, we present an approach based on Economic Price Theory for guiding the process of microdata anonymisation such that optimum levels of privacy and information utility are achieved. / Thesis (PhD)--University of Pretoria, 2010. / Computer Science / unrestricted

Cette thèse porte sur l’influence des facteurs sémantiques dans la résolution de problèmes additifs isomorphes, et sur les différences de difficulté en résultant. Les contextes statiques favorisent la stratégie basée sur la recherche de la valeur de la partie complémentaire et ceux de type temporel favorisent l’analogie entre éléments homologues. L’objectif est de : (i) montrer que les situations de transformation d’états sont intermédiaires entre les situations statiques et temporelles, (ii) faire appliquer à des contextes statiques la procédure favorisée par le contexte temporel et inversement. Les expériences sont réalisées auprès d’élèves de CM1/CM2. La première atteste du statut intermédiaire des situations de transformation d’état, leur conférant un rôle pivot potentiel pour certaines acquisitions. Les problèmes de transvasement favorisent moins la solution fondée sur le complément que les énoncés de type ensembliste et moins la solution fondée sur la comparaison que ceux de type temporel. Dans la seconde expérience, deux conditions d’apprentissage sont testées : l’une par instruction écrite, l’autre par intervention pédagogique orale. Cette dernière favorise nettement la stratégie par différence-comparaison pour des problèmes d’effectifs, et celle par différence-complément pour les problèmes d’âges. L’effet de généralisation est plus marqué dans le groupe qui a appris la stratégie par différence-comparaison. Dans l’apprentissage écrit, la stratégie différence-comparaison est transférée aux problèmes d’effectifs et généralisée aux problèmes non appris ; la stratégie différence-complément n’est pas transférée aux contextes inhabituels. / This thesis examines semantic factors in additive problem solving and the related differences in difficulties. The problems studied can be solved by two strategies: the complementation strategy, based on a step by step procedure; and the matching procedure, based on the analogy between homologous elements. The two objectives of this work are: (i) to show that change problems are intermediate between combination problems with frequency contexts and combination problems with age contexts; (ii) to transfer to age problems the complementation procedure usually applied to frequency problems, and transfer to frequency problems the matching strategy usually applied to age problem. The experiments were conducted with children of 4th and 5th grades. The first experiment demonstrates that the change situations are intermediate between frequency and age problems. less often solved by a complementation strategy than frequency problems and less often solved by a matching strategy than age problems. In the second experiment, two teaching situations were tested. The first consisted in giving written instruction, in order to transfer the matching strategy to frequency problems, and to transfer the complementation procedure to age problems the transfer was observed for the matching strategy but not for the complementation strategy. The second teaching method consisted in oral lessons in class, the goal bieing similar: a massive effect of transfer of both procedures was observed as well as a generalization effect to problems with other contexts.