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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Paramyxovirus persistence

Fearns, Rachel January 1995 (has links)
In this study, SV5 infection of Balb/c mouse fibroblast cells has been used as a model system to investigate the possible mechanisms underlying the establishment and maintenance of Paramyxovirus persistence. It was found that following entry to these cells, the virus initiated a wave of transcription and replication, similar to that of a permissive infection, in which normal levels of each of the virus proteins were synthesized. However, by 48-72 hours post infection (p.i.) there was an almost complete cessation of virus mRNA and protein synthesis. Despite the decrease in virus activity, full length viral genome RNA and P and NP, the proteins involved in transcription and replication, could be detected at consistently high levels up to 5 days p.i., although the levels of HN, M, F and V declined. Immunofluorescence analysis supported these data showing that at later times p.i. although there were some cells positive for all the viral proteins, a high proportion of cells were strongly positive for NP, L and P, but negative for M, F and HN. In these cells, NP, L and P were often located in discrete cytoplasmic foci. These results suggested that the persistently infected cell population consisted of some cells in which the virus was active and other in which it was quiescent within cytoplasmic inclusions. A series of cell lines was established from a monolayer of Balb/c cells that had been infected at a high multiplicity. Immunofluorescence studies showed only a minority of cells in these clones to be infected with virus, indicating that during division, not all daughter cells became infected. Of the infected cells, some were positive for all the viral proteins, while others were positive for only NP and P. Co-cultivation of the cloned cells with Vero cells, which are permissive for SV5 replication, rapidly yielded non-defective virus, suggesting that the virus was active in some cells. These results suggested that the persisting virus was in a state of flux, able to reside as inclusions of inactive nucleocapids from which it could reactivate to initiate a new round of infection. Experiments aiming to determine if the persistently infected cells were resistant to immune attack demonstrated that cells at 5 days p.i., in which the majority of cells were quiescently infected, were less susceptible to immune lysis than cells at 1 day p.i. in which there was ongoing protein synthesis. Further experiments were carried out both to try to determine what had induced the persistent state in mouse cells and also to examine factors which might induce a similar state in different cell lines.
2

Molecular cloning of flavonoid 3¡¦,5¡¦-hydroxylase cDNA from the petals of Verbena x hybrida

Hung, Cheng-yu 12 July 2004 (has links)
Flavonoid 3¡¦,5¡¦-hydroxylase (F3¡¦,5¡¦H) is the key enzyme that catalyzesthe anthocyanin biosynthesis pathway for the expression of blue or purple flower color. The garden crops of Verbena x hybrida were used to clone its F3¡¦,5¡¦H gene for the investigation of flower color engineering and regulatory program. Degenerate primers were designed from the conservative regions of other published F3¡¦,5¡¦H genes to amplify the expectant DNA fragment . A full-length cDNA of the F3¡¦,5¡¦H gene designated VhFH1 (AY604727) was cloned by the method of 5¡¦and 3¡¦ RACE, and its genomic DNA sequence was isolated by the IPCR strategy. Nucleotide sequence alignment revealed that VhFH1 contains two introns and a 1542 bp open reading frame encoding a polypeptide of 514 amino acid residues, and there could be a promoter sequence with TATA box signal in the upstream of the transcription start site. The amino acid sequence of VhFH1 was compared with the previous reported F3¡¦,5¡¦H and showed between 50¢Mand 77¢Midentity with those species. The expectant molecular mass and isoelectric point of VhFH1 protein is 57 KD and 7.69, respectively. There are three typical motifs of the F3¡¦,5¡¦H that belongs to the cytochrome P450 proteins in the VhFH1 predicted protein. According to the above-mentioned conjecture, VhFH1 is a full-length cDNA of the F3¡¦,5¡¦H gene in the V. hybrida. This cDNA fragment was inserted into the plant expression vector pCambia 1304 and could be detected the expression in E. coli by RT-PCR and protein electrophoresis. It is practicable to transform the horticultural plants with these vectors to create novel flower colors in the future. Furthermore, transcripts of the F3¡¦,5¡¦H gene were detected in the blue, purple and white flowers but not in the red one as revealed by RT-PCR. These results are advantageous in the further investigation of regulatory factors of the anthocyanin biosynthesis pathway in the V. hybrida.
3

F2:F3b Ratio and BOC-Adjusted PHC F3 Approach to Resolving False Detections of Crude Oil and Diesel Drilling Waste in Clean Soils and Manure Compost

Kelly-Hooper, Francine Teresa 17 July 2013 (has links)
The Canadian Council of Ministers of the Environment (CCME) endorsed the Reference Method for the Canada-Wide Standard (CWS) for Petroleum Hydrocarbons (PHC) in Soil – Tier 1 Method in 2001. The purpose of the CWS is to provide laboratories with analytical methods for producing accurate and reproducible PHC soil chemistry analysis results. CWS PHC concentrations are reported according to the following carbon ranges/fractions: F1 (C6-C10), F2 (C10-C16), F3 (C16-C34) and F4 (>C34). The Canada-wide Standards for Petroleum Hydrocarbons (PHC) in Soil provide generic soil quality guidelines for the each of the four PHC fractions. The CWS PHC extraction solvents inadvertently co-extract natural biogenic organic compounds (BOC) from organic soils. BOCs, such as waxes and fatty acids, are produced by living organisms such as plants, animals and microbes. PHC analysis of highly organic clean soils and manure compost can cause false exceedences of the F3 soil quality guidelines. This thesis presents a new mathematical Tier 2 approach to resolving biogenic interferences through the use of biogenic versus petrogenic Gas Chromatography - Flame Ionization Detector (GC-FID) chromatogram patterns produced by the CWS PHC Tier 1 method. This approach is based on the results of four studies: i) 300-day crude oil contaminated peat and sand microcosm experiment; ii) 300-day diesel drilling waste contaminated manure compost and sand microcosm experiment; iii) PHC analysis of 14 light to heavy crude oils and iv) Canadian background PHC soil field survey. These studies determined that the clean soils and compost had F3 ranges that were dominated by the F3b sub-fraction range (C22-C34). In contrast, the F3a (C16-C22) and F3b sub-fraction ranges were evenly distributed in the 14 fresh light to heavy crude oils. The diesel drilling waste was strongly dominated by the F3a sub-fraction range. The second important trend was that F2 concentrations were either non-detectable or slightly detectable in all of the clean soils and compost samples. In contrast, F2 concentrations were strongly prevalent in all of the crude oils and in the diesel drilling waste. F2 and F3b concentrations were applied to the F2:F3b ratio, which identified PHC absence in the clean materials (<0.10 ratio) and PHC presence (>0.10 ratio) in the contaminated materials. The %F3a:%F3b distributions were applied to the BOC-adjusted PHC F3 calculation, which estimated true PHC F3 concentrations in the clean and contaminated soils and manure compost. The combination of these two approaches provided an accurate and efficient solution to resolving false detections of crude oil and diesel PHCs and false exceedences of F3 soil toxicity guidelines by in clean soils and compost.
4

The ecology of <i>Brassica napus</i>

Seerey, Nicole J. 14 April 2010
Volunteer canola (<i>Brassica napus</i> L.) has become an abundant weed in western Canadian cropping systems. Modern canola cultivars are strong competitors and produce large seed yields, however seed shattering during harvest creates large volunteer seedbanks. The segregation of hybrid trait and changes in variability of traits may allow successive generations of volunteer <i>B. napus</i> weeds to display different levels of fitness and other traits. Three cultivars: 2 hybrid, and 1 open-pollinated at three consecutive generations: G1, the initial crop; G2, first generation of volunteers; and G3 the second generation of volunteers, were used to evaluate the competitive ability, fitness and population dynamics of volunteer canola when grown as a weed in wheat (<i>Triticum aestivum</i> L.). Traits including seed, biomass, and pod production, plant height, seed weight, dormancy, and competitive ability were measured. In all traits but height and seed weight, hybrid breakdown occurred, as the hybrid G1displayed greater mean values than the G2 generation. Hybrids commonly showed the highest mean values of various traits in the G1, lowest mean values in the G2. Hybrid G3 populations produced mean values not different from the G1 or G2 generations for many traits. The open-pollinated cultivar displayed mean values for all traits which did not vary across generations. Generational differences in <i>B. napus</i> seedlings resulted in differences in wheat yield losses. <i>B. napus</i> densities at maturity provided a more robust model of wheat yield loss, as there were differences in wheat yield losses due to the interaction of generation and cultivar of <i>B. napus</i>. Commercial seed generations were the most competitive and fit plants, while volunteer generations were less competitive, and not as fit.
5

The ecology of <i>Brassica napus</i>

Seerey, Nicole J. 14 April 2010 (has links)
Volunteer canola (<i>Brassica napus</i> L.) has become an abundant weed in western Canadian cropping systems. Modern canola cultivars are strong competitors and produce large seed yields, however seed shattering during harvest creates large volunteer seedbanks. The segregation of hybrid trait and changes in variability of traits may allow successive generations of volunteer <i>B. napus</i> weeds to display different levels of fitness and other traits. Three cultivars: 2 hybrid, and 1 open-pollinated at three consecutive generations: G1, the initial crop; G2, first generation of volunteers; and G3 the second generation of volunteers, were used to evaluate the competitive ability, fitness and population dynamics of volunteer canola when grown as a weed in wheat (<i>Triticum aestivum</i> L.). Traits including seed, biomass, and pod production, plant height, seed weight, dormancy, and competitive ability were measured. In all traits but height and seed weight, hybrid breakdown occurred, as the hybrid G1displayed greater mean values than the G2 generation. Hybrids commonly showed the highest mean values of various traits in the G1, lowest mean values in the G2. Hybrid G3 populations produced mean values not different from the G1 or G2 generations for many traits. The open-pollinated cultivar displayed mean values for all traits which did not vary across generations. Generational differences in <i>B. napus</i> seedlings resulted in differences in wheat yield losses. <i>B. napus</i> densities at maturity provided a more robust model of wheat yield loss, as there were differences in wheat yield losses due to the interaction of generation and cultivar of <i>B. napus</i>. Commercial seed generations were the most competitive and fit plants, while volunteer generations were less competitive, and not as fit.
6

F2:F3b Ratio and BOC-Adjusted PHC F3 Approach to Resolving False Detections of Crude Oil and Diesel Drilling Waste in Clean Soils and Manure Compost

Kelly-Hooper, Francine Teresa 17 July 2013 (has links)
The Canadian Council of Ministers of the Environment (CCME) endorsed the Reference Method for the Canada-Wide Standard (CWS) for Petroleum Hydrocarbons (PHC) in Soil – Tier 1 Method in 2001. The purpose of the CWS is to provide laboratories with analytical methods for producing accurate and reproducible PHC soil chemistry analysis results. CWS PHC concentrations are reported according to the following carbon ranges/fractions: F1 (C6-C10), F2 (C10-C16), F3 (C16-C34) and F4 (>C34). The Canada-wide Standards for Petroleum Hydrocarbons (PHC) in Soil provide generic soil quality guidelines for the each of the four PHC fractions. The CWS PHC extraction solvents inadvertently co-extract natural biogenic organic compounds (BOC) from organic soils. BOCs, such as waxes and fatty acids, are produced by living organisms such as plants, animals and microbes. PHC analysis of highly organic clean soils and manure compost can cause false exceedences of the F3 soil quality guidelines. This thesis presents a new mathematical Tier 2 approach to resolving biogenic interferences through the use of biogenic versus petrogenic Gas Chromatography - Flame Ionization Detector (GC-FID) chromatogram patterns produced by the CWS PHC Tier 1 method. This approach is based on the results of four studies: i) 300-day crude oil contaminated peat and sand microcosm experiment; ii) 300-day diesel drilling waste contaminated manure compost and sand microcosm experiment; iii) PHC analysis of 14 light to heavy crude oils and iv) Canadian background PHC soil field survey. These studies determined that the clean soils and compost had F3 ranges that were dominated by the F3b sub-fraction range (C22-C34). In contrast, the F3a (C16-C22) and F3b sub-fraction ranges were evenly distributed in the 14 fresh light to heavy crude oils. The diesel drilling waste was strongly dominated by the F3a sub-fraction range. The second important trend was that F2 concentrations were either non-detectable or slightly detectable in all of the clean soils and compost samples. In contrast, F2 concentrations were strongly prevalent in all of the crude oils and in the diesel drilling waste. F2 and F3b concentrations were applied to the F2:F3b ratio, which identified PHC absence in the clean materials (<0.10 ratio) and PHC presence (>0.10 ratio) in the contaminated materials. The %F3a:%F3b distributions were applied to the BOC-adjusted PHC F3 calculation, which estimated true PHC F3 concentrations in the clean and contaminated soils and manure compost. The combination of these two approaches provided an accurate and efficient solution to resolving false detections of crude oil and diesel PHCs and false exceedences of F3 soil toxicity guidelines by in clean soils and compost.
7

A study of the foreman's status in the highway construction industry

Faddis, William Claud January 1968 (has links)
The status of a foreman in modern day production is dependent upon a number of' factors, many of which are beyond his control. It has been said that the foreman stands "victim, not monarch” in this situation which has been created largely by economic conditions in our economy. But, these conditions have not affected all industries in the same manner. It is the purpose of this paper to investigate the status determining conditions in the highway construction industry. To evaluate these status determining conditions, the highway construction industry is first studied through existing library sources. To substantiate these findings, empirical research was then done in two highway construction firms, one large and one small. The following criteria were used to evaluate the foreman's status: influence on top management in decision making, economic contributions to the firm, authority over production, staff interference, foreman control within his division, channels of information, visibility of position to top management, upward mobility, security of position ease of replacement, operative skill level supervised, importance of position in the firm, and remuneration. From the information gathered, it appears that foremen in the highway construction industry have a higher status rating than do most foremen in other types or industries. / M.S.
8

[en] CONVOLUTIONAL NEURAL NETWORK FOR SEISMIC HORIZONS IDENTIFICATION / [pt] IDENTIFICAÇÃO DE HORIZONTES EM SÍSMICA USANDO REDE NEURAL CONVOLUCIONAL

MAYARA GOMES SILVA 07 November 2022 (has links)
[pt] O petróleo e gás são importantes na economia mundial, utilizados como matéria-prima em vários produtos. Para a extração desses produtos é necessário realizar a caracterização dos reservatórios de hidrocarbonetos. A partir dessa caracterização são extraídos um volume com dados sísmicos da região de interesse. Esses dados são interpretados para identificação de várias características, como a classificação de fácies sísmicas, horizontes, falhas, e gás. A grande quantidade de dados do volume de sísmica, torna a interpretação manual cada vez mais desafiadora. Muitos pesquisadores da área de interpretação sísmica tem investido em métodos utilizando redes neurais. As redes neurais convolucionais (CNN) são muito utilizadas em problemas de visão computacional, e obtém ótimos resultados em muitos problemas com dados 2D. O presente trabalho tem como objetivo a aplicação de redes neurais convolucionais no mapeamento supervisionado de horizontes sísmicos. Avaliamos nossa proposta usando o bloco F3 com as anotações de fácies sísmicas. Os dados foram utilizados baseados em modelo de seção e patches. Na previsão de horizonte foram avaliadas as arquiteturas da ResUnet e DC-Unet. Como função de perda foram analisadas a Generalized Dice e a perda Focal Tversky. O método mostrou resultados promissores com a ResUnet e função de perda Focal Tversky, nos dados baseados em patches de 128x128, alcançando aproximadamente 56 por cento na métrica Dice. A implementação completa e as redes treinadas estão disponíveis em https://github.com/mayaragomys/seismic_horizons. / [en] Oil and gas are important in the world economy, used as raw materials in various products. For the extraction of these products, it is necessary to carry out the characterization of the hydrocarbon reservoirs. This characterization extracts a volume with seismic data from the region of interest. These data are interpreted to identify various features, such as the classification of seismic facies, horizons, faults, and gas. A large amount of seismic volume data makes manual interpretation increasingly challenging. Many researchers in the field of seismic interpretation have invested in methods using neural networks. Convolutional Neural Networks (CNN) are widely used in computer vision problems and get great results in many situations with 2D data. The present work aimed to apply convolutional neural networks in the supervised mapping of seismic horizons. We evaluated our proposal using the F3 block with seismic facies annotations. The data representation in the input layer are patches of sections. In the horizon forecast, we evaluate the architectures of ResUnet and DC-Unet. We use the Generalized Dice and the Focal Tversky loss functions for the loss function. The method delivered promising results with the ResUnet and Focal Tversky loss function on data based on 128x128 patches, reaching approximately 56 percent on the Dice metric. The full implementation and the trained networks are available at https://github.com/mayaragomys/seismic_horizons.
9

Mesures comparées des paramètres acoustiques chez des locuteurs bègues et non-bègues tunisiens / Comparative measurements of acoustic parameters in tunisian stutterers’ and non-stutterers

Slama, Nadia 26 November 2016 (has links)
Cette thèse porte sur l’étude de paramètres acoustiques dans parole fluente chez des locuteurs bègues (SB) et des non-bègues (SNB), tunisiens.Les paramètres acoustiques comparés entre SB et SNB incluent le temps d’établissement du voisement (ou V.O.T), la fréquence du fondamental (F0), des mesures du Jitter et du Shimmer, l’étendue et la direction de la transition du second formant (F2), et également les trois premiers formants (F1, F2 et F3) des trois voyelles /a, i, u/. Les résultats sont en accord avec les études antérieures en ce qui concerne le V.O.T, qui serait aussi plus long chez les bègues américains et français. Concernant les valeurs du F0, des différences significatives entre les deux groupes sont obtenues pour /u/. Les mesures du Jitter et du Shimmer ne montrent pas de différences significatives, contrairement aux résultats recueillis chez les bègues américains où la signification est obtenue pour les mesures du Shimmer. Enfin,en ce qui concerne l’étude des variations formantiques, il y a des tendances sans atteindre la signification pour F1, F2 et F3. Les mesures de F2 sont moins élevées chez les bègues avec quelques résultats significatifs obtenus pour les séquences du type C-u. Le triangle vocalique des trois voyelles /a i u/ chez les enfants bègues tunisiens n’est totalement centralisé contrairement aux triangles obtenus chez les locuteurs bègues français et américains, selon la littérature. / This thesis concerns the comparison of acoustic parameters in fluent speech in Tunisian stutterers’ speakers (SB) and non-stutterers (SNB), Tunisians.The acoustic parameters which are compared between SB and SNB include the Voice Onset Time (VOT), the fundamental frequency (F0), the measurements of jitter and shimmer, the scope and direction of the transition of the second formant (F2), and the first three formants (F1, F2 and F3) of the three vowels /a, i, u/. The results are consistent with previous studies regarding the V.O.T, which has been found also be longer for American and French stutterers. Concerning F0values, significant differences between the two groups are obtained for /u/. Measurements of jitter and shimmer show no significant differences, contrary to the results found from American concerning the shimmer. Finally, as regards the study of formant variations, there are tendencies without reaching significance for F1, F2 and F3. F2 values are lower in stutterers with significant results obtained for sequences of C-u. The vowel triangle of the three vowels /a, u, i/ in Tunisian children who stutter, is not centralized, unlike triangles obtained for French and American stuttering speakers, according to the literature.
10

An Acoustical Analysis of the American English /l, r/ Contrast as Produced by Adult Japanese Learners of English Incorporating Word Position and Task Type

Chase, Braden Paul 01 June 2017 (has links)
Adult Japanese learners of English (JLEs) are often stereotyped as being unable to produce or perceive the English phonemes /l/ and /r/. This study analyzed acoustic samples of /l/ and /r/ obtained from intermediate-level Japanese speakers in two variable contexts: word positions (initial/final) and task type (controlled/free). These tokens were subjected to acoustic analysis which is one way of comparing oral productions of native and non-native English speakers. Previous research has identified a lowered third formant (F3) as the hallmark of an American English /r/ as produced by a native speaker, independent of word position or task type. The results indicate that participants can produce appropriate and statistically significant differences (p<.001) between these two phonemes across word position and task type. Other findings indicate that neither task type nor word position had a significant effect on F3 values. These results indicate that Japanese speakers of English may have the ability to distinguish /l/ from /r/ without specialized pronunciation training, but these differences are less dramatic as identified by F3 frequency values that those produced by native English speakers when producing these contrasting phonemes. In most tokens, however, large effect sizes remained between JLE productions and NES standards.

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