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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.
261

Privacy-Preserving Data Integration in Public Health Surveillance

Hu, Jun 16 May 2011 (has links)
With widespread use of the Internet, data is often shared between organizations in B2B health care networks. Integrating data across all sources in a health care network would be useful to public health surveillance and provide a complete view of how the overall network is performing. Because of the lack of standardization for a common data model across organizations, matching identities between different locations in order to link and aggregate records is difficult. Moreover, privacy legislation controls the use of personal information, and health care data is very sensitive in nature so the protection of data privacy and prevention of personal health information leaks is more important than ever. Throughout the process of integrating data sets from different organizations, consent (explicitly or implicitly) and/or permission to use must be in place, data sets must be de-identified, and identity must be protected. Furthermore, one must ensure that combining data sets from different data sources into a single consolidated data set does not create data that may be potentially re-identified even when only summary data records are created. In this thesis, we propose new privacy preserving data integration protocols for public health surveillance, identify a set of privacy preserving data integration patterns, and propose a supporting framework that combines a methodology and architecture with which to implement these protocols in practice. Our work is validated with two real world case studies that were developed in partnership with two different public health surveillance organizations.
262

Genetic analysis, QTL mapping and gene expression analysis of key visual quality traits affecting the market value of field pea

Ubayasena, Lasantha Chandana 15 April 2011
Visual quality is one of the major factors that determine the market value of field pea (Pisum sativum L.). Breeding for improved visual quality of pea seeds is currently a challenging task, because of the complexity and lack of sound genetic knowledge of the traits. The objectives of this research were to characterize the genetic basis and identify the genomic regions associated with four key visual quality traits (cotyledon bleaching in green pea, greenness in yellow pea, and seed shape and seed dimpling in both green and yellow types) in field pea. Biochemical and gene expression profiling to understand the molecular basis of post-harvest cotyledon bleaching in green pea was also addressed. Two F5:6 recombinant inbred line (RIL) populations (90 lines from Orb X CDC Striker cross, and 120 lines from Alfetta X CDC Bronco cross) were developed and evaluated for visual quality traits in two locations in Saskatchewan, Canada in 2006 and 2007. The four quality traits evaluated all displayed a continuous range of expression with moderate to high heritability. Two genetic linkage maps utilizing 224 markers (29 simple sequence repeat (SSR) (from Agrogene) and 195 amplified fragment length polymorphism (AFLP)) and 223 markers (27 SSR and 196 AFLP ) were constructed for the Orb X CDC Striker population and the Alfetta X CDC Bronco population, respectively. Multiple quantitative traits (QTL) mapping detected major QTLs on linkage group (LG) IV and LG V, as well as location- and year-specific QTLs on LG II and LG III associated with green cotyledon bleaching resistance. Nine QTLs controlling yellow seed lightness, three for yellow seed greenness, 15 for seed shape and nine for seed dimpling were detected. Among them, 5 QTLs located on LG II, LG IV and LG VII were consistent in at least two environments. The QTLs and their associated markers will be useful tools to assist pea breeding programs attempting to pyramid positive alleles for the traits. The bleaching resistant cultivar CDC Striker had a slower rate of chlorophyll degradation in cotyledons and a higher carotenoid to chlorophyll ratio in seed coats than the bleaching susceptible cultivar Orb when seed samples were exposed to high intensity light. An oligo-nucleotide microarray (Ps6kOLI1) was utilized to investigate the gene expression profiles of CDC Striker and Orb seed coats at different developmental stages. It clearly indicated that the expression of genes involved in the production and accumulation of secondary metabolites was significantly different between these cultivars. The results of both biochemical and gene expression studies suggested the bleaching resistance in CDC Striker was not due to the accumulation of chlorophyll pigments in the cotyledons, but rather due to the ability of seed coats to protect them from photooxidation. Accumulation of specific carotenoids which could bind with the reaction center protein complex more effectively and accumulation of phenolic secondary metabolites which could enhance the antioxidant properties and structural integrity of the seed coats may lead to the bleaching resistant phenotype. Therefore, breeding green pea cultivars with higher seed coat antioxidant properties would improve both visual and nutritional quality. This research has provided several insights into molecular approaches to improve field pea visual quality for food markets.
263

Poverty alleviation and biodiversity conservation in rural Brazil: a case study of the Cananeia Oyster Producers' Cooperative

Medeiros, Dean 28 March 2006 (has links)
The designation and enforcement of protected areas in southeast Brazil severely restricted livelihoods of rural inhabitants, who had limited options to adapt to new settings. Serious challenges emerged from deficiency in local capacity for the organization, management, and application of mitigation interventions. However, the Cananéia Oyster Producers’ Cooperative managed to overcome numerous challenges and was a finalist for the United Nations Development Programme’s 2002 Equator Prize for simultaneous poverty alleviation and biodiversity conservation. Qualitative research methods, including Rapid Rural Appraisal tools, were employed to examine the cooperative’s self-organization, cross-scale institutional linkages, and livelihood and conservation impact. Through various coordinated endevours such as the adoption of oyster rearing beds, depuration station, education, and designation of an extractive reserve, cooperative members have been able to improve their livelihoods while minimizing environmental impact. Lessons learned from the cooperative on simultaneous poverty alleviation and biodiversity conservation are presented in the final chapter of this thesis. / May 2006
264

Linkage and Association Mapping of Seed Size and Shape in Lentil

2013 April 1900 (has links)
The seed size and shape of lentil are important traits because they determine the market class, cooking time, and can influence quality and yield of milled lentils. Understanding the genetic control of seed size and shape can help breeders develop varieties with improved seed size and shape characteristics such as seed diameter, seed thickness and seed plumpness. The objectives were to determine the heritability of seed size and shape and identify the genomic regions controlling these traits. This involved i) developing a linkage map for the LR-18 population (CDC Robin x 964a-46) using a recently developed single nucleotide polymorphism (SNP) assay; ii) analyzing the LR-18 population for seed size and shape QTLs; iii) analyzing an association mapping panel for seed size and shape QTLs. Phenotyping trials were grown at two different locations in Saskatchewan, Canada. The mapping population was grown in two different years while the association panel was only grown in one. Seed diameter and thickness were measured using sieves and this data were used to calculate seed plumpness. Days to flowering was also recorded to determine if it had any effect on seed size or shape. A linkage map consisting of 537 SNPs, 10 SSRs and 4 morphological markers on seven linkage groups was constructed and used for the QTL analysis. The heritability estimates were high for seed diameter and seed plumpness (0.92 and 0.94, respectively) while for seed thickness and days to flowering they were more moderate (0.60 and 0.45, respectively). QTL analysis revealed QTLs on five of the seven linkage groups. The association mapping study revealed similar heritability estimates of 0.97, 0.62, 0.94, and 0.62 for seed diameter, seed thickness, seed plumpness and flowering time, respectively. There were 31 different significant marker trait associations, however only 5 of those were significant for both locations. Four of those five markers did not map in the LR-18 linkage map so their genomic locations are still to be determined. Results showed that there are key regions in the genome that control seed size and shape and flowering time in lentil. These markers could be used for marker-assisted selection or for further candidate gene analysis.
265

Exploring the Genetics of SLE with Linkage and Association Analysis

Johansson, Cecilia January 2004 (has links)
The aim with this thesis has been to identify genes involved in the pathogenesis of Systemic Lupus Erythematosus (SLE). SLE is a systemic autoimmune disorder, most likely caused by both several genetic and environmental factors. In order to identify susceptibility loci for the disease we performed linkage analyses on data from 70 families of various ethnic origins. Significant linkage was found in two regions. One region (chromosome 17p12-q11) was linked to SLE in a set of Argentine families. Since the same region had been previously identified in several linkage studies on Multiple Sclerosis patients, we propose that this locus may contain a genetic variant that affects not only SLE, but also autoimmunity in general. The second locus is located on chromosome 4p14-13 and has only been identified in a set of Icelandic families. We suggest that this locus contains a mutation that has been enriched in the Icelandic population due to its population history. The BCL2 gene has been suggested as a candidate gene for SLE. Three markers in this gene were investigated for association with the disease in two different populations. However, no association could be found with any of the markers or when these markers were analysed together as a haplotype. We conclude that the BCL2 gene is not associated with SLE in our material. This result contradicts previously published results of an association between BCL2 and SLE. We suggest that the PD-1 pathway (involved in inhibition of T- and B-cell responses) is an important component in SLE pathogenesis. A regulatory variant in the PD-1 gene had previously been associated with SLE and here we show strong association (p<0.0001) to a haplotype containing SNPs in both PD-L1 and PD-L2. Our results indicate that SLE is a disease caused by several genetic variations that differ between families and populations.
266

Inheritance and linkage of morphological, isozyme and RAPD markers in grasspea

Chowdhury, Mahboob Alam 01 January 1997 (has links)
Experiments were conducted to determine the outcrossing rate, the inheritance of markers and establish a basic linkage map in grasspea, <i> Lathyrus sativus </i>L. The outcrossing rate in a white-flowered line of grasspea ranged from 1.7 to 2.7% among eight combinations of gene frequency and location. The outcrossing rate in this study (2.2 ± 0.7%) suggests that individual lines of grasspea should be maintained in isolation to maintain their genetic integrity. Inheritance and linkage were determined for one morphological, 11 isozyme and 72 RAPD markers in five F<sub>2</sub> populations (all RAPD markers were in one F<sub>2</sub> population). The inheritance of flower colour was monogenic with colour dominant over white. The isozymes, ACO-1, ACO-2, AAT-1, AAT-2, EST-6, FDH, LAP-1, PGD-2, SKDH and TPI-1, were codominantly expressed with monogenic inheritance. The isozymes LAP-1 and PGD-2 segregated in a non-Mendelian ratios in the crosses PI 426891.1.3 x PI 283564c.3.2 and PI 426891.1 x PI 172930.4, respectively. The isozymeEST-3 was monogenically inherited and dominantly expressed. Most RAPD markers segregated in a 3:1 ratio. Marker UBC368<sub>425/655</sub> segregated in a co-dominant fashion. The RAPD markers UBC304<sub>831</sub>, UBC304<sub>964</sub>, UBC308<sub>990</sub>, UBC322<sub>1432</sub>, UBC328<sub>831</sub>, UBC332<sub>1118</sub>, UBC3321<sub>1581</sub>, UBC333<sub>617</sub>, UBC349<sub>752<?sub>, UBC365<sub>1013</sub> and UBC388<sub>459</sub> showed distorted segregation. In two F<sub>2</sub> populations, PI 283564c.3 x PI 426885.2 and PI 358601.5 x PI 173714.5, a linkage between AAT-2 and SKDH was reconfirmed. In the cross PI 426891.1.3 x PI 283564c.3.2, one morphological, three isozyme and 71 RAPD markers were mapped resulting in the delineation of 14 linkage groups including 69 markers (1 morphological, 3 isozyme and 65 RAPD markers). The total genome length covered by these 75 markers (69 linked and six unlinked) was about 864 cM. Considering cost, simplicity and abundance, RAPD analysis was more efficient than isozyme analysis in developing linkage map.
267

Genetic analysis, QTL mapping and gene expression analysis of key visual quality traits affecting the market value of field pea

Ubayasena, Lasantha Chandana 15 April 2011 (has links)
Visual quality is one of the major factors that determine the market value of field pea (Pisum sativum L.). Breeding for improved visual quality of pea seeds is currently a challenging task, because of the complexity and lack of sound genetic knowledge of the traits. The objectives of this research were to characterize the genetic basis and identify the genomic regions associated with four key visual quality traits (cotyledon bleaching in green pea, greenness in yellow pea, and seed shape and seed dimpling in both green and yellow types) in field pea. Biochemical and gene expression profiling to understand the molecular basis of post-harvest cotyledon bleaching in green pea was also addressed. Two F5:6 recombinant inbred line (RIL) populations (90 lines from Orb X CDC Striker cross, and 120 lines from Alfetta X CDC Bronco cross) were developed and evaluated for visual quality traits in two locations in Saskatchewan, Canada in 2006 and 2007. The four quality traits evaluated all displayed a continuous range of expression with moderate to high heritability. Two genetic linkage maps utilizing 224 markers (29 simple sequence repeat (SSR) (from Agrogene) and 195 amplified fragment length polymorphism (AFLP)) and 223 markers (27 SSR and 196 AFLP ) were constructed for the Orb X CDC Striker population and the Alfetta X CDC Bronco population, respectively. Multiple quantitative traits (QTL) mapping detected major QTLs on linkage group (LG) IV and LG V, as well as location- and year-specific QTLs on LG II and LG III associated with green cotyledon bleaching resistance. Nine QTLs controlling yellow seed lightness, three for yellow seed greenness, 15 for seed shape and nine for seed dimpling were detected. Among them, 5 QTLs located on LG II, LG IV and LG VII were consistent in at least two environments. The QTLs and their associated markers will be useful tools to assist pea breeding programs attempting to pyramid positive alleles for the traits. The bleaching resistant cultivar CDC Striker had a slower rate of chlorophyll degradation in cotyledons and a higher carotenoid to chlorophyll ratio in seed coats than the bleaching susceptible cultivar Orb when seed samples were exposed to high intensity light. An oligo-nucleotide microarray (Ps6kOLI1) was utilized to investigate the gene expression profiles of CDC Striker and Orb seed coats at different developmental stages. It clearly indicated that the expression of genes involved in the production and accumulation of secondary metabolites was significantly different between these cultivars. The results of both biochemical and gene expression studies suggested the bleaching resistance in CDC Striker was not due to the accumulation of chlorophyll pigments in the cotyledons, but rather due to the ability of seed coats to protect them from photooxidation. Accumulation of specific carotenoids which could bind with the reaction center protein complex more effectively and accumulation of phenolic secondary metabolites which could enhance the antioxidant properties and structural integrity of the seed coats may lead to the bleaching resistant phenotype. Therefore, breeding green pea cultivars with higher seed coat antioxidant properties would improve both visual and nutritional quality. This research has provided several insights into molecular approaches to improve field pea visual quality for food markets.
268

Extremal Functions for Contractions of Graphs

Song, Zixia 08 July 2004 (has links)
In this dissertation, a problem related to Hadwiger's conjecture has been studied. We first proved a conjecture of Jakobsen from 1983 which states that every simple graphs on $n$ vertices and at least (11n-35)/2 edges either has a minor isomorphic to K_8 with one edge deleted or is isomorphic to a graph obtained from disjoint copies of K_{1, 2, 2, 2, 2} and/or K_7 by identifying cliques of size five. We then studied the extremal functions for complete minors. We proved that every simple graph on nge9 vertices and at least 7n-27 edges either has a minor, or is isomorphic to K_{2, 2, 2, 3, 3}, or is isomorphic to a graph obtained from disjoint copies of K_{1, 2, 2, 2, 2, 2} by identifying cliques of size six. This result extends Mader's theorem on the extremal function for K_p minors, where ple7. We discussed the possibilities of extending our methods to K_{10} and K_{11} minors. We have also found the extremal function for K_7 plus a vertex minor.
269

Designing Mechanisms for Specific Rolling-Sliding Properties

Wu, Yi-hsien 09 February 2012 (has links)
This work is initiated from an observation of the rolling-sliding kinematic behavior observed in the motion of the knee joint. We use the slip ratio as a parameter to analyze the rolling-sliding properties of a mechanism, and also propose a method to design new mechanisms with specific slip ratio. In this research, we first verify the many definitions of the slip ratio, then modify a best definition to suit various rolling-sliding motions. Most importantly, we propose two types of rolling-sliding mechanism design. By changing the parameters of the mechanism, we can adjust its slip ratio curve to be close to a desired curve. In addition, when the idea of adjustable link length is used in the design of the mechanism, exact slip ratio curve as specified can be generated by the use of some cams.
270

Design of a Robust Controller for the Smart Flexible Linkage Using Genetic Algorithms

Chen, Jhih-jyun 27 June 2005 (has links)
The purpose of this thesis is to study the active robust control for the flexible slider-crank linkage mechanism with piezoelectric films using genetic algorithms. The instability caused by the inertia force that is induced by the high-speed rotation flexible slider-crank linkage, mode truncation, parameter uncertainties, and spillover effect due to the residual modes of structure. For the application of the mechanical structure system, a mathematical model for a slider-crank linkage mechanism with piezoelectric films is developed in conjunction with finite element method (FEM), and the lower frequency modes are separated into controlled modes and residual modes. For the robustness of the system, a robust stability condition and genetic algorithms are employed to ensure the stability of the system under the parameter uncertainties and spillover effect simultaneously. Numerical simulation is performed to the control methodology with genetic algorithms can suppress deform of flexible slider-crank linkage mechanism operating at high speeds, and the instability caused by the parameter uncertainties and spillover effect can be avoided.

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