No description available.

No description available.

This paper highlights some ofthe methodological challenges which have arisen in collecting data for an international study on positive action measures. It will describe strategies employed to encourage participation in the study from as wide a range of organisations and individuals using a mixed method approach. The paper will also discuss the methodological and sensitive issues related to this type of research in organisations and strategies adopted by the research team to ameliorate any problems that have arisen whilst maintaining trustworthiness and rigour in the study.

La réplication de l'ADN chez les eucaryotes commence lorsque le complexe de reconnaissance de l'origine (ORC) se lie à l'ADN puis recrute les facteurs nécessaires à la duplication du génome. Bien que les mécanismes biochimiques et les facteurs impliqués dans l'initiation de la réplication semblent être conservés, les séquences d'ADN (les origines de réplication) sur lesquelles ces événements ont lieu ne le sont pas. L'ensemble des données connues suggèrent fortement un rôle prépondérant de la mise en place des origines de réplication dans la structuration du génome et l'organisation des autres processus cellulaires lors de la différenciation. Comprendre la coordination de ces processus in vivo et au cours du développement est primordial pour déchiffrer la régulation cellulaire dans son contexte réel. Le modèle du développement embryonnaire du nématode C.elegans constitue un outil génétique de premier choix pour l'étude de la mise en place des origines de réplication au cours du développement. Au cours de ma thèse, j'ai dû premièrement développer une technique de culture de C.elegans synchronisée en grosse échelle, afin d'obtenir le matériel nécessaire pour identifier les origines de réplication. Cette technique nous a aussi permis de caractériser, pour la première fois, la croissance synchronisée en bioréacteur d'un métazoaire. D'autre part, l'étude des origines de réplication a révélé une distribution hétérogène des origines de réplication dans les chromosomes qui corrèle avec des domaines de certaines marques épigénétiques, une corrélation avec des séquences d'ADN capables de former des structures cruciformes de l'ADN, ainsi comme une confirmation de la corrélation avec la transcription. Nous avons aussi vu que la corrélation de origines de réplication avec des CpG, est fortement établie après le début de la gastrulation, et que l'association avec des éléments fonctionnels spécifiques du génome, comme les operons, est perdu une fois la transcription embryonnaire deviens nécessaire après la gastrulation. L'ensemble de résultats suggèrent fortement un changement dans l'organisation des origines de réplication après gastrulation, qui corrèle avec des éléments fonctionnels du génome. / Eukaryotic DNA replication begins when the origin recognition complexes (ORC) binds to DNA and recruits the necessary factors for genome duplication. Even though, biochemical mechanisms as well as the factors involved seem to be well conserved, the DNA sequences (replication origins) where these events take place are not. The known data strongly suggest that replication origins establishment may play an important role in genome structuring as well as in the organization of other cellular processes during cell differentiation. To understand how these processes are coordinated in vivo and during development, is essential for deciphering cellular regulation in its real context. C.elegans embryonic development is a genetic tool of first choice for studying replication origins in vivo and their correlation with other genome features and processes during development.During my thesis and with the aim of obtaining enough material for the replication origins identification method, I've had to develop a new technique of synchronized high-scale liquid culture of the nematode C.elegans. This technique has allowed the characterization for the first time of the synchronize growth of a metazoan in bioreactor. Furthermore, the study of replication origins has revealed a heterogenic distribution of replication origins along chromosomes that correlates with specific epigenetic marks. Moreover, replication origins are strongly associated with specific DNA structures able to form cruciforms, and we have confirmed the correlation of replication origins and transcription. This study also show that the association of replication origins with CpGs is greatly increased after gastrulation, and that the association with some genetic elements, such as operons, is reduced after gastrulation begins. Taken together these results show a change of replication origins before and after cell differentiation during embryonic development that correlate with functional genome elements.

Thesis (Ph.D. (Mathematics Education)) -- University of Limpopo, 2018 / The purpose of the study is to explore the effectiveness of Annual National Assessment (ANA) in monitoring the standard of mathematics education and to assess the mathematical proficiencies tested and exhibited by Grade 9 learners in South Africa. The research problem was premised on the dearth of data that justifies ANA as an evaluative assessment. As such, the study utilised five strands which were; procedural fluency, conceptual understanding, strategic competence, adaptive reasoning and productive dispositions as a theoretical framework to assess mathematics that was tested and exhibited by learners. To explore the research problem, the study used mixed methods in the context of exploratory sequential design. Document analysis was used first to capture mathematics content and cognitive levels examined by ANA. Second, learner responses were explored using four variables of achievement levels; no response, correctly answered, incorrectly answered and partially answered. First, the results from the analysis of ANA questions indicated that ANA mostly tested questions of low complexity. Second, the results from the learners’ responses revealed that the majority of learners were not proficient to ANA irrespective of low complexity testing. Third, the Porter’s alignment index for ANA and TIMSS was between moderate and perfect. Subsequently, content and cognitive levels were misaligned in the three consecutive years of ANA testing. It implies that learners were most likely to show a deficit of higher order problems solving skills which are a prerequisite of courses in advanced mathematics. Additionally, the results suggest that ANA had challenges of reliability and validity as an evaluative assessment due to inconsistency in the testing. As such, it is recommended that the complexity of ANA be addressed, the content areas where learners are not proficient be addressed and the alignment of ANA must be frequently calculated to monitor the standard of mathematics education in South Africa effectively. Keywords Alignment index, mean deviation, strands of mathematical proficiency, systemic assessment.

The goal of the splice girder research project 0-6652 funded by the Texas Department of Transportation is to utilize the full potential of splicing prestressed TX girders continuously. The TX girder family of beams is cost effective alone due to their simple, repetitive fabrication, but to truly optimize their potential would be to span several beams together as one continuous unit. The weight and length restrictions allowed by trucks or barges limit the prestressed beam lengths. Therefore, splicing together prestressed beams becomes the solution to the transporting obstacle. As a result, the prestressed girders will be more competitive to other bridge types such as steel I-girders, steel trapezoidal girders, cable-stayed bridges, and concrete segmental bridges. In fact, a prestressed/post-tensioned concrete bridge is preferred over steel designs in highly corrosive environments such as the coast or in snow regions where de-icing chemicals are used. In comparison, to a segmental box girder bridge, the post-tensioned prestressed bridge has reduced complexity due to fewer segments and the number of reduced joints susceptible to corrosion. The issue that arises with splicing prestressed beams is that in the process of connecting them together an opening must be made to install the post-tensioning (PT) steel strands. The openings are created by installing several steel or plastic circular ducts into the web region. Since the post-tensioning results in a reduction of the concrete web region, a modification is necessary to the shear capacity equation. The experimental study performed at the Ferguson Structural Engineering Laboratory consisted of fabricating and testing two full-scale prestressed Tx46 girders. One girder contained a plastic post-tensioning duct with grout and steel strands installed in the web region. The other beam was a standard Tx46 beam fabricated without a duct. Both beams had a reinforced concrete deck installed with an overhang to model an actual bridge section. Furthermore, the purpose of the standard beam was to serve as a direct comparison to the beam with a duct and determine the actual reduction in shear capacity. The research and findings will include the impact of the plastic duct in the Tx46 compared to the control beam. The failure loads of the test specimens will be compared to the current 2012 AASHTO code predictions for shear design. Also, revisions to the AASHTO code will be recommended if necessary. The primary goal of this research was to improve the design and detailing of the skewed end-blocks commonly used in these beams. As U-beams had been in service for several decades without incident, it was anticipated that there would be little need for change in the design, and the findings of the research would involve a slight tweaking to improve the overall performance. / text

Thesis (M. Div.)--Emmanuel School of Religion, Johnson City, Tennessee, 2001. / Vita. Includes bibliographical references (leaves 63-65).

Thesis (M. Div.)--Emmanuel School of Religion, Johnson City, Tennessee, 2001. / Vita. Includes bibliographical references (leaves 63-65).

Thesis (M. Div.)--Emmanuel School of Religion, Johnson City, Tennessee, 2001. / Vita. Includes bibliographical references (leaves 63-65).

Este trabalho apresenta os resultados das investigações teórica e experimental sobre a aderência de cordoalhas pré-tracionadas, em concretos de alta resistência com e sem fibras de aço. Foram utilizadas cordoalhas de sete fios com &#934p 12,7 mm e fibras de aço curtas, com ganchos nas extremidades (DRAMIX) e fator de forma 1/d=45. Foram realizados dois tipos de ensaios: arrancamento e flexão em viga. Os parâmetros estudados foram: comprimento de ancoragem (5&#934p, 7&#934p e 15&#934p), volume de fibra (zero, 40 kg/m3 e 60 kg/m3 e grau de protensão (zero e 0,8fptk). O concreto apresentou resistências à compressão de 50 MPa no momento da transferência da protensão e 68 MPa na data de ensaio, aproximadamente. Os resultados dos dois tipos de ensaio foram analisados e comparados com as prescrições normativas da NBR 6118 (2001), da FIB Bulletin 1 (1999) e do ACI 318 (2002), onde verificou-se que as prescrições se encontram a favor da segurança. A conclusão principal resultante desta pesquisa foi que a utilização de fibras com 40 kg/\'m3 por metro quadrado não influi na aderência. Já para um volume de fibra de 60 kg/\'m3 por metro quadrado há um ganho de aproximadamente 28% na aderência, em relação aos concretos sem fibras de aço, nos ensaios de arrancamento. Para as vigas, não houve ganho de aderência para os volumes de fibra utilizados, nem na determinação do comprimento de transferência, nem na do comprimento de ancoragem necessário. / This study presents the results of a theoretical and an experimental investigation of the bond of pretensioned strands embedded in plain and steel fiber reinforced high strength concrete. There were used seven wires strands with 12,7 mm diameter and short hooked steel fibers with an aspect ratio of 1/d=45. Two types of tests were carried out to obtain the bond characteristics of the strands: pullout tests and beam under flexure tests. The parameters studied were the volume fraction (0%, 0,51% and 0,76%) of the fibers, and the degree of prestress of the strand (zero and 0,8fptk). The concrete compressive strength was 50 MPa at transfer (3 days of age) and 68 MPa at 28 days of age (test date), approximately. The results were analyzed and compared to the provisions of the following Codes: NBR 6118 (2001) (Brazilian code under public consult), ACI-318 (2002) and FIB-Bulletin 1 (1999). The comparison indicated that the codes give a safe design. The main conclusion of this work was that the use of 0,5% of steel fibers does not influence the bond strength of the strand. The use of 0,76% of steel fibers increases the bond stress in 28% when compared with plain concrete, for the pullout tests. For the beam\'s tests there was no bond improvement due to the steel fibers, in both case (0,5% and (0,76%), neither for the transfer length nor for the development length.