title: Seroprevalence, production impacts, economics and risk factors of Mycobacterium avium subspecies paratuberculosis in Canadian dairy cattle

contributor: Keefe, Greg (Supervisory Committee Member)

contributor: Tremblay, Rob (Supervisory Committee Member)

contributor: Markham, Fred (Supervisory Committee Member)

format: 328 electronic application/pdf

subject:
Agriculture, Animal Pathology
Biology, Veterinary Science

abstract: The purpose of this thesis was to determine the seroprevalence, production impacts, economics and risk factors associated with Mycobacterium avium subspecies paratuberculosis (MAP) in Canadian dairy herds. Seroprevalence of bovine leukemia virus (BLV) and bovine viral diarrhoea virus (BVDV), and production impacts of BLV, BVDV and Neospora caninum (NC) were also estimated. Within 373 randomly selected Canadian herds (from New Brunswick, Nova Scotia, Prince Edward Island, Quebec, Ontario, Manitoba, Saskatchewan and Alberta), a serum sample was obtained from approximately 30 randomly selected lactating animals for ELISA testing for exposure to BLV, MAP and NC, while 5 unvaccinated cattle over 6 months of age were selected for virus neutralization testing for exposure to BVDV.

abstract: Seroprevalence at the cow level was 30.3% and 3.1% for BLV and MAP, respectively. At the herd level, 76.6% had at least one seropositive cow for BLV, 31.2% had at least one animal with a titer >1:64 for BVDV, and 18.9% had at least two seropositive cows for MAP. The Global Moran's I statistic for BLV and MAP indicated significant positive spatial autocorrelation of 0.16 and 0.15. The K-function for BVDV did not indicate any significant spatial autocorrelation. Using the spatial scan statistic, 4 and 1 significant clusters were detected for BLV and MAP-seroprevalence, respectively. No significant clusters were detected for BVD.

abstract: Regarding 305 day milk production (305 d milk), MAP-seropositivity was significantly associated with a lower 305 d milk of 212 kg in 4-plus lactation cows. NC-seropositivity was associated with a lower 305 d milk of 158 kg in primiparous cows compared to NC-seronegative primiparous cows. Cows in BVDV-seropositive herds (at least one unvaccinated animal with a titer ≥ 1:64) had significantly lower 305 d milk (by 368 kg) compared to cows in BVDV-seronegative herds. Among 1st lactation animals, NC-seropositivity was associated with a significant reduction of 5.5 kg and 3.3 kg of 305 d fat and 305 d protein yields, respectively. However, there were no statistically significant effects of MAP-seropositivity on 305 d fat or 305 d protein yields. BVDV-seropositivity (at the herd level) was associated with reductions in 305 d fat and 305 d protein yields of 10.20 kg/cow and 9.46 kg/cow, respectively. Regarding somatic cell counts, NC- (4+ lactation) and MAP-seropositivity were associated with a 0.094 decrease and 0.098 increase in the lactational mean of the log 10 somatic cell count. The cows in BVDV-seropositive herds had a significant increase in the mean log10 somatic cell count of 0.096. BLV-seropositivity was not associated with 305 d milk, 305 d fat, 305 d protein or mean log 10 somatic cell count. There was no significant effect modification of any of the outcomes examined from interaction between seropositivity for any of the pathogens.

abstract: For all reasons of culling, MAP-seropositive cows had a 1.38 (95% C.I., 1.05--1.81) times increased hazard of culling compared to MAP-seronegative cows. Seropositivity for the other pathogens was not associated with an increased risk of overall culling. Among cows that were culled because of either decreased reproductive efficiency or decreased milk production or mastitis, MAP-seropositive cows were associated with 1.55 (95% C.I., 1.12--2.15) times increased hazard compared to MAP-seronegative cows. Among cows that were culled because of reproductive inefficiency, NC-seropositive cows had a 1.43 (95% C.I., 1.15--1.79) times greater hazard than NC-seronegative cows. Among cows that were culled because of decreased milk production, cows in BVDV-seropositive herds had a 1.86 (95% C.I., 1.28--2.70) times increased hazard compared to cows in BVDV-seronegative herds. BLV-seropositive cows did not have an increased risk of reason-specific culling as compared to BLV-seronegative cows. No significant interaction on culling among seropositivity for the pathogens was detected, but only a limited number of cows tested seropositive for multiple pathogens. Results from our research will help in better understanding the economic impacts of these pathogens and justification for their control.

abstract: For the MAP-seropositive Canadian dairy herds, the mean loss per 61-cow herd was CD $2,992 (95% C. L, $143--$9741) annually, or CD $49 per cow per year. Herd additional culling losses were responsible for 46% (CD $1374) of the total losses from MAP. Decreased milk production, mortality and reproductive losses accounted for 9% (CD $254), 16% (CD $488) and 29% (CD $875) of the losses, respectively.

abstract: The following factors were significantly associated with the number of MAP-seropositive cows: "more than one cow in the maternity pen", "group housing in pre-weaned calves in winter", "purchasing open heifers", "direct contact with beef cattle", "BVDV-seropositive herds" and "not having proper BVD vaccination in calves (i.e. animals were not boostered 2-4 weeks after their first killed inoculation)" with count ratios of 1.69, 2.03, 2.34, 1.27, 1.41 and 1.77, respectively. The variable "herds having BVDV modified live vaccination in calves" was associated with 0.44 times fewer MAP-seropositive cows. There were significant regional differences in the number of positive cows per herd that were not explained by the management factors included in the final multivariable model. In the logistic portion of the final Zero Inflated Negative Binomial model, a one unit increase in the mean lactation number of cows tested in a herd was associated with an increase of 1.44 times the odds of being herds having at least one MAP-seropositive cow. Herds having "feeding total mixed ration" and "bedding that was not added frequently to calving areas (for each calving)" were associated with 3.1 and 2.7 times greater odds of being MAP-seropositive herds, respectively. The variables "NC-seropositivity" and "area of pasture (more than 200 acres)" were marginally significant (P  0.10) with MAP-seropositivity.

abstract: The results from this study will improve the knowledge of seroprevalence, production impacts, economical losses and risk factors of MAP in Canadian dairy industry and will assist management recommendations in national Johne's control programs.

abstract: Source: Dissertation Abstracts International, Volume: 68-01, Section: B, page: 0142.


title: Shell disease in impounded populations of the American lobster, Homarus americanus, in Nova Scotia, Canada

type: Text Dissertation/Thesis

contributor: Lewis, J. (Supervisory Committee Member)

contributor: Speare, D. (Supervisory Committee Member)

contributor: Ikede, B. (Supervisory Committee Member)

format: 73 electronic application/pdf

subject:
Biology, Veterinary Science
Agriculture, Fisheries and Aquaculture

abstract: The overall research goal was to identify risk factors for the development of shell disease in impounded populations of the American lobster,  Homarus americanus. Shell disease, a disease syndrome characterized by progressive erosions and necrosis of the exoskeleton of aquatic crustaceans, continues to be one of the most prevalent and costly conditions affecting captive populations.

abstract: An epidemiological study was designed to evaluate the association between physiological and environmental factors and the development of shell disease on an individual lobster level. Initial health assessments on fresh caught post-harvest lobsters from Southwest Nova Scotia dealers showed significant differences between dealers, depending on the location of their respective fishing grounds (lower total protein levels, softer shells, and a higher proportion of intermolt lobsters in the primarily mid-shore dealer compared to the primarily inshore dealer).

abstract: Monthly observations of frequency and characteristics of shell disease lesions were performed during the storage period. Logistic regression results showed total protein as the strongest predictor of shell disease (odds ratios ranged from 4.3 to 32.8 for lobsters with low total protein levels, versus lobsters with high protein levels). The lobsters' molt stage also emerged as an important predictor for shell disease (odds ratios of 2.1 and 2.4 at models for 30 and 90 days storage) with a trend towards a relationship in the 60 and 120 day models, suggesting that the timing of the fishery in Southwest Nova Scotia in relation to the molt cycle is important in determining the post storage prevalence of shell disease in impoundment facilities. Shell hardness showed significance only in the 30 day model (odds ratio of 1.6), suggesting that this factor may only be important early in the storage period while sludge removal from the surface of the lobster was significant in 2 of the final models (odds ratios of 1.7 and 2.0 at 90 and 120 days, respectively), with a trend towards significance in the remaining two models, suggesting that the sludge offers some protective benefits to the captive lobsters.

abstract: From the perspective of a long term storage facility, the quality of the lobsters entering the facility is critical and, as this study shows, determines the extent to which shell disease will develop.

abstract: Source: Masters Abstracts International, Volume: 46-03, page: 1426.


title: Someone has to care: Computer-assisted instruction and struggling readers

contributor: O'Donoghue, Fiona (Supervisory Committee Member)

contributor: Kelly, Ursala (Supervisory Committee Member)

format: 96 electronic application/pdf

subject:
Education, Reading
Education, Technology of

abstract: Over a three month period in a high school on Prince Edward Island, I conducted a study involving three volunteer, struggling readers and the computer-assisted reading instruction software program, Academy of Reading 2000. While my initial goal was to improve students' reading ability, I was hoping to explore the efficacy of computer-assisted instruction (CAI) in a high school setting and to make recommendations regarding its use. What I learned indirectly from the literature on CAI and directly from my own experience with the students was that CAI can be a useful tool for struggling readers but it cannot replace one-on-one quality attention from a teacher. Although CAI was moderately effective, the human component in assisting struggling readers is vital. With adequate training and support, CAI can be considered an aid for teachers who have time to understand the complex literacy issues facing individual students with reading difficulties. The more I learned, from interviews with the three students and their parents, the more I was able to understand the context and possible alternatives for their reading challenges. It is the three stories of these students—one with a documented history of learning difficulties and assessments, one with an undocumented history of an inability to focus and severe reading difficulties, and one learning English as a second language who was apparently without reading difficulties—that will give teachers, parents, and students themselves insights into the difficulties of achieving success by using any one tool for reading intervention. What is needed most in the school system is someone who both cares and has the time to help the students make a difference in their learning.

abstract: Source: Masters Abstracts International, Volume: 42-02, page: 0392.

abstract: Adviser: Anne-Louise Brookes.


title: Spatial and temporal patterns of decapod larvae in the Strait of Georgia, British Columbia

contributor: Teather, Kevin (Supervisory Committee Member)

contributor: Pohle, Gerhard (Supervisory Committee Member)

format: 200 electronic application/pdf

subject:
Biology, Ecology
Biology, Oceanography

abstract: The abundance and dispersal of meroplankton play a fundamental role in determining spatial and temporal patterns of benthic organisms in marine systems. Field studies that quantify abundance patterns are heavily dependent on, and often limited by, proper identification resources. In the present study, diagnostic features of laboratory reared Glebocarcinus oregonensis zoeae were described to facilitate identification of cancrid zoeae in the Salish Sea. The larval community was then described from two surveys spanning the Strait of Georgia that were conducted in consecutive spring seasons in 2009 and 2010. Interannual variability in larval abundance, diversity (Shannon index), and similarity between revisited stations was quantified to compare assemblages between years. Finally, the species- and stage-specific abundance and horizontal distribution of three cancrid species including  Cancer productus, G. oregonensis, and Metacarcinus magister,  were described from surveys conducted in consecutive spring and summer seasons in 2010.

abstract: The zoeae of G. oregonensis exhibited much shorter and acutely angled lateral exospines on the telson and much longer posterolateral abdominal spines than other local cancrid species. Other morphological features used to identify G. oregonensis in previous studies were found to be misleading. In both years the reptantian decapod larval community consisted of at least 10 families but was dominated by cancrid larvae (approximately 80 % of total larval abundance). Although the relative abundance of the different families was generally consistent with reproductive potential and timing, overall measures of larval abundance, diversity, and similarity between samples were significantly different between years. Large variation in total abundance, possibly caused by heavy mortality in 2009 or increased reproductive output in 2010, could result in a large variation in the year class strength of adult crab populations. Spatial patterns of both total larval abundance and diversity also contrasted between years, and although they were sometimes moderately correlated with environmental variables, these correlations were found not to be consistent enough to function as good predictors of total larval abundance (all species and stages combined). Larvae of C. productus were apparently released later than those of G. oregonensis and M. magister. Larval distributions of these cancrid species did not change dramatically from stage to stage, indicating that transport did not occur rapidly. The distribution of larvae and environmental variables indicated the potential for nearshore retention and/or alongshore larval transport within the central Strait's eastern margin and cross-strait transport in the southern region. Fresh water input from the Fraser River appeared to play an important role in shaping larval distributions, especially for  M. magister.

abstract: Source: Masters Abstracts International, Volume: 50-04, page: 2252.

abstract: Adviser: Pedro Quijon.


title: Statistical models for binary repeated measures and hierarchical data in veterinary science

contributor: Greenwood, Spencer (Supervisory Committee Member)

contributor: Hammell, K. Larry (Supervisory Committee Member)

format: 279 electronic application/pdf

subject: Biology, Biostatistics

abstract: The objective of the thesis was to assess the performance of statistical procedures for the analysis of binary longitudinal data in veterinary science, specifically, to describe and quantify their performance in terms of statistical properties such as unbiasedness, confidence interval coverage and efficiency. The focus was on marginal and random effects procedures including: ordinary logistic regression (OLR), alternating logistic regression (ALR), generalized estimating equations (GEE), marginal quasi likelihood (MQL), penalized quasi likelihood (PQL), pseudo likelihood (REPL), maximum likelihood (ML) and Bayesian Markov chain Monte Carlo (MCMC). The marginal and random effects procedures handle the within-subject dependence differently, and they offer different interpretations of regression estimates for binary longitudinal data. Several simulation studies covered a wide range of data structures and designs including a two-level balanced longitudinal design, a three-level balanced setting of binary repeated measures data, and repeated measures data with missing values. A statistical simulation approach was used as the tool for the assessment.

abstract: The first study involved a two-level setting of binary repeated measures data. Results for the marginal model data showed the autoregressive GEE showed to be highly efficient when treatment was within subjects, even with strongly correlated responses. For treatment between subjects, random effects methods also performed well in some situations; however, a small number of subjects with short time series proved a challenge for both marginal and random effects methods. Results for the random effects model data showed bias in estimates from random effects methods while the marginal model produced estimates close to the marginal parameters.

abstract: The second study involved binary repeated measures data with an additional hierarchical structure. Results indicate that in data generated by random intercept models, the ML and MCMC procedures performed well and had fairly similar estimation errors. The PQL regression estimates were attenuated while the variance estimates were less accurate than ML and MCMC, but the direction of the bias depended on whether binomial or extra-binomial dispersion was assumed. In datasets with autocorrelation, random effects estimates procedures gave downward biased estimates, while marginal estimates were little affected by the presence of autocorrelation. The results also indicate that in addition to ALR, a GEE procedure that accounts for clustering at the highest hierarchical level is sufficient. The REPL procedure performed poorly and produced unsatisfactory estimates regardless of autocorrelation values.

abstract: The third study involved binary repeated measures data with an additional hierarchical structure and missing values, where five different scenarios of simulated incomplete datasets were considered. The first scenario corresponded to a combination of three types of missingness patterns present in a real (scc40) dataset: delayed entry and drop-outs as well as intermittent missing values. The remaining scenarios involved only drop-outs, and corresponded to either moderate or high percentages of values either missing at random (MAR) or not missing at random (NMAR), respectively.

abstract: In the first scenario, all estimation procedures except OLR performed well and produced estimates with small relative bias (generally less than 5%) for levels of missingness that roughly corresponded to the scc40 data. In MAR missingness scenarios, some biases were found for ALR, GEE and PQL procedures, whereas the likelihood-based procedures were largely unaffected by the missing values. In NMAR scenarios, all procedures experienced similar and strong biases in the time coefficient; however, fixed effects estimates at the subject and cluster level were relatively unaffected. The presence of autocorrelation in the data did not substantially alter the impact of missing values although the shrinkage of random effects estimates was marginally less pronounced than in the full datasets.

abstract: Additionally, a hierarchical data structure arising in an aquaculture vaccine trial on Infectious Salmon Anaemia Virus (ISAV), where multiple treatment groups of fish in the same tanks were observed over time, was studied. The focus was to assess and account for neighbour treatment effects. By neighbour treatment effects in an incomplete block design setting, we mean that treatments present in the same block (tank) may affect each other in their performance. Two statistical models were proposed to assess and account for neighbour treatment effects. The first approach was based on a non-linear model, and the second involved cross-classified and multiple membership models. The performance of the models was evaluated by simulation.

abstract: Results demonstrated that both proposed models show promise in capturing neighbour treatment effects of the type assumed, whenever such neighbour effects are of at least moderate magnitude. Analyses of the ISAV trial data by both models did not provide any evidence of substantial neighbour effects.

abstract: Source: Dissertation Abstracts International, Volume: 70-08, Section: B, page: 4570.


title: Stereochemical control in lactide polymerization: from polymer stars to catalyst design

contributor: Kerr, Russell (Supervisory Committee Member)

contributor: Bissessur, Rabin (Supervisory Committee Member)

format: 180 electronic application/pdf

subject:
Chemistry, Analytical
Chemistry, Polymer

abstract: Poly(lactic acid) (PLA), a renewable, biodegradable, bioassimilable polymer derived from plant sources has become the focus of intensive research over the past 15 years. PLA technology has evolved greatly, with the development of metal catalysts that can control the insertion of lactide monomers, to prepare stereoregular PLAs. The emergence of more complicated brush, dendrimer and star-like polymer architectures provide novel platforms to which this stereocontrol has not been applied. By combining the concepts of stereocontrol and star polymer architecture valuable information regarding the structure property relationships of these PLAs can be learned.

abstract: We have prepared the first series of stereoregular PLA polymer stars utilizing known aluminum catalysts and dipentaerythritol, a multi-functional initiator. Stars bearing atactic, heterotactic, isotactic-rac and isotactic-L microstructures have been prepared. The materials have been characterized by gel permeation chromatography, 1H NMR spectroscopy, thermogravimetric analysis, differential scanning calorimetry and powder X-ray diffraction to elucidate the effect that stereocontrol has on the properties of these novel star polymers. The physical properties of these materials were found to be enhanced through the inclusion of stereoregularity. The isotactic samples are especially tunable by varying the percent tacticity. By changing the microstructure of the star PLAs, the glass transition temperatures (Tg) and melt temperatures (Tm) can be tuned by 10°C, while the thermal onset stability of the samples can be improved by 40°C through microstructure control. The dependence of observed properties on tacticity and molecular weight have been examined through the preparation of higher molecular weight isotactic stars, which exhibit 13°C and 25°C improvements in Tg and Tm respectively when accompanied by a 5 fold increase in molecular weight. These materials have also been subjected to degradation studies to assess the quality of these materials in sustained release for drug delivery applications. Microstructure control has afforded these samples huge improvements in solution stability, with a 3-fold increase in lifetime observed between atactic and isotactic-rac stars.

abstract: Efforts to improve the stereocontrolled polymerization of lactide have been expanded to include the design and synthesis of novel aluminum anilido-aldimine catalysts incorporating diisopropylphenyl and cyclohexyl substituents on the anilido donors. These complexes have been screened in lactide polymerization to prepare PLA, and have been subjected to kinetic analyses.

abstract: Source: Masters Abstracts International, Volume: 50-04, page: 2439.


title: Students in transition:  Teacher as researcher

contributor: Hopkirk, Gerry (Supervisory Committee Member)

format: 117 electronic application/pdf

subject:
Education, Educational Psychology
Education, Secondary
Education, Curriculum and Instruction

abstract: The purpose of this research was to hear the stories of eight Grade 10 students about their change from Grade 9 to Grade 10 in order to (1) find out what they found difficult or helpful; (2) to find out, based on their stories, what can be done to improve the transition; and (3) to help students examine the difference, as defined by Hertzog and Morgan (1999), between a one-time event over which they have no control, and an ongoing process of transition that can be reflected upon and improved when understood. My goal was to explore with the students the meaning attributed to this transition. In addition, I have worked with them to generate possible ways for improving the transition process. From this perspective, my intent was to engage students in a qualitative participatory research project that was relevant to their lives. I reflected upon and made sense of my observations and experiences for the purpose of applying them to my practice as a teacher. This research was important to me as a teacher who helps students adjust to a high school culture which, in many ways, is different from the junior high culture. The two forms of transition, systemic and developmental, proposed by Queen (2002) were readily apparent in my research. The participants I spoke with all reported varying degrees of anxiety about what to expect from teachers and how they might meet what they perceived to be the higher expectations of teachers and parents. This kind of anxiety is relevant to the category of systemic transition developed in Queen's (2002) study. Again, in keeping with his findings, most of my participants seemed to experience the second level of transition which includes such issues as: how to establish friendships with peers, how to fit with peers, how to make decisions about drug and alcohol use.

abstract: Source: Masters Abstracts International, Volume: 44-03, page: 1126.


title: Studies examining the standardization of hematology and clinical chemistry analyses for Atlantic salmon (Salmo salar) blood

contributor: Donald, A. (Supervisory Committee Member)

contributor: Groman, D.B. (Supervisory Committee Member)

contributor: Honor, D.J. (Supervisory Committee Member)

contributor: Johnson, G. (Supervisory Committee Member)

format: 160 electronic application/pdf

subject:
Biology, Cell
Biology, Veterinary Science

abstract: Standardization of procedures for handling and processing salmonid blood samples were evaluated for: enumerating blood cells, hemoglobin determination, differential blood cell counts, hematological diluents, collection and evaluation of plasma for clinical chemistry. In addition, the effect of anaesthesia, anticoagulant, and sample handling were examined with regards to clinical chemistry and hematological indices. Normal range determinations were completed for fresh and salt water maintained Atlantic salmon (Salmo salar). The effects of hemorrhagic stress on "total particle counts" (TPC), hematocrit (Hct), hemoglobin (Hb), total protein (TP), absolute numbers of reticulocytes, mean cell volume (MCV), mean cell hemoglobin concentration (MCHC), and liver enzymes including: alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and sorbitol dehydrogenase (SDH) were additionally examined for samples from fish maintained in fresh water.

abstract: Correlation coefficients indicated no difference between automated versus manual cell counts. The Coulter Model ZBI was chosen for enumerating fish cells. Automated hemoglobin measurements were higher than results of the manual method. Leucocrit was accurate as a first approximation of the total "White Blood Cell" count. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 31-02, page: 0722.


title: Studies of polymorphonuclear leucocyte function and of gross and microscopic lesions in sheep experimentally infected with Trypanosoma brucei and T. congolense

contributor: Cawthorn, Rick (Supervisory Committee Member)

contributor: Pringle, J. (Supervisory Committee Member)

format: 144 electronic application/pdf

subject:
Biology, Microbiology
Agriculture, Animal Pathology
Biology, Veterinary Science
Health Sciences, Immunology

abstract: Polymorphonuclear leucocyte (PMN) function was assessed in trypanosome-infected sheep to establish its possible contribution to lowering of body defence. Sheep were inoculated with Trypanosoma congolense and T. brucei. Each infected sheep received eight million trypomastigotes intravenously.

abstract: Although sheep infected with T. congolense developed parasitaemia, there were no clinical signs of trypanosomiasis. Sheep infected with T. brucei developed parasitaemia, clinical signs of trypanosomiasis and alteration in PMN function. PMNs obtained from infected sheep had significant decrease in superoxide anoin production and nylon wool adherence, but enhanced phagocytosis of opsonized zymosan.

abstract: Clinical disease of T. brucei infection in sheep was characterized by pyrexia, anorexia, weight loss, anaemia, and inflammatory edema of skin of the head, neck, brisket, distal limbs, and tail. At the end of the trial, the sheep were euthanised and examined for lesions. There was edema of the skin and enlargement and edema of superficial lymph nodes. Microscopic lesions were observed in the skin, superficial lymph nodes, spleen and kidneys. Skin lesions consisted of severe edema accompanied by diffuse perivascular and periadnexal dermatitis, perineuritis, lymphangitis, distension of lymphatic vessels with fluid, and lymphatic thrombosis in the dermis and subcutis. Inflammatory reaction extended deep into subcutis leading to severe panniculitis and myositis. Inflammatory cells were mainly macrophages, plasma cells, and lymphocytes although polymorphonuclear leucocytes were also present. Numerous trypanosomes were seen in skin lesions. Superficial lymph nodes had severe capsular lymphadenitis and lymphoid hyperplasia. The spleen had lymphoid hyperplasia. Lesions in the kidney consisted of mild to moderate glomerulonephritis and a few tubular casts. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 33-01, page: 0120.

abstract: Advisers: Barbara Horney; Basil Ikede.


title: Studies on host -pathogen interactions of infectious salmon anaemia virus

contributor: Kibenge, Frederick S.B. (Thesis advisor)

contributor: Ikede, Basil (Supervisory Committee Member)

contributor: Cepica, Arnost (Supervisory Committee Member)

contributor: Groman, Dave (Supervisory Committee Member)

contributor: Hammell, Larry (Supervisory Committee Member)

contributor: Brown, Laura (Supervisory Committee Member)

format: 205 electronic application/pdf

subject: Biology, Microbiology

subject: Agriculture, Animal Culture and Nutrition

subject: Biology, Veterinary Science

subject: Agriculture, Fisheries and Aquaculture

abstract: Infectious salmon anemia (ISA) virus (ISAV), an economically important pathogen in marine aquaculture has been classified in the family  Orthomyxoviridae, genus Isavirus. ISAV is known to cause overt and fatal systemic infection in farmed Atlantic salmon and asymptomatic infection in both farmed and feral fish. It is well documented that Atlantic salmon that recover from clinical ISA as well as subclinically infected trout and herring can transmit ISAV to healthy Atlantic salmon through cohabitation. The mechanisms of pathogenesis and persistence of ISAV are not adequately studied at the molecular level. This study investigated the host-pathogen interactions of ISAV. Major aspects of this study included the determination of mechanisms of cell death during ISAV infection of fish cells and the exploration of the novel phenomenon of antibody-mediated growth of ISAV in macrophage-like fish cell lines.

abstract: Two general pathways known to cause viral cytopathic effect (CPE) are apoptosis and necrosis. In this study, three permissive fish cell lines SHK-1, CHSE-214, and TO were used to determine if ISAV-induced CPE is due to apoptosis or necrosis. Characteristic apoptotic DNA fragmentation was observed only in ISAV-infected SHK-1 and CHSE-214 cells. The apoptosis was confirmed by use of the fragment end labeling assay. ISAV-infected TO cells did not undergo apoptosis but showed leakage of the high mobility group 1 (HMGB1) protein from the nucleus which is characteristic of cells undergoing necrosis. Infected SHK-1 cells did not show leakage of HMGB1 protein. Infection with two different strains of ISAV showed that the induction of apoptosis correlated with the appearance of CPE in SHK-1 cells. These cells did not show caspase-3-like proteolytic activity. The ISAV-induced apoptosis was however inhibited by a pan-caspase inhibitor, Z-VAD-fmk, indicating it is caspase dependent. The ISAV putative PB2 protein and translation products of RNA segment 7 specifically bound caspase-8 in vitro suggesting that these viral proteins may have a role in the ISAV-induced apoptosis.

abstract: To study ISAV-antibody interactions, virus neutralization (VN) was performed in the three cell lines using three strains of ISAV and rabbit or fish anti-ISAV sera. (Abstract shortened by UMI.).

abstract: Source: Dissertation Abstracts International, Volume: 65-09, Section: B, page: 4406.

abstract: Adviser: Frederick S. B. Kibenge.


title: Studies on molecular mechanisms of virulence of infectious bursal disease virus

contributor: Arella, M. (Supervisory Committee Member)

contributor: Chan, Cathy (Supervisory Committee Member)

contributor: Lopez, Alfonso (Supervisory Committee Member)

contributor: Markham, R.J. Frederick (Supervisory Committee Member)

format: 148 electronic application/pdf

subject:
Biology, Molecular
Biology, Microbiology
Agriculture, Animal Pathology
Biology, Veterinary Science

abstract: Infectious bursal disease virus (IBDV) is the etiological agent of a highly contagious immunosuppressive disease in young chickens. Spontaneous enhancement of virulence has occurred without significant changes in antigenicity of circulating classical virulent strains. The sites on the viral genome involved in such virulence variations and the underlying molecular mechanisms are poorly understood. Since the rate of viral replication influences virus virulence, attempts were made to map the regulatory sequences involved in IBDV genome expression and replication. A series of chimeric genes containing various lengths of the 5′ noncoding sequences of IBDV segment A were constructed and analysed for promoter activity by measuring their capacity to direct the expression of the luciferase reporter gene. Progressive deletions of the 5′ noncoding region of 131 bp of segment A of IBDV and transient transfection studies identified a minimal region of 32 bp that had maximal promoter activity without any enhancer activity. Attempts were also made to isolate virus variants able to escape neutralizing antibody. A partial neutralization resistant mutant of IBDV was isolated by serially passaging a QC2 strain of IBDV in Vero cells in the presence of polyclonal antibody, and its phenotypic and genotypic characteristics were studied. The selected mutant had similar growth characteristics as the parental virus but had a smaller plaque morphology. Its genome segment A had an additional  Pst I restriction site in the major antigenic region. There were four and three nucleotide exchanges in the 3′ noncoding regions of segments A and B respectively and none in the 5′ noncoding regions. Moreover, less severe pathology in the bursa of Fabricius and higher virus neutralization titres. Such a variant may be useful in the development of attenuated vaccines of IBDV. Furthermore, efforts were made to develop a reverse genetics system for IBDV by constructing two independent full-length cDNA clones containing segments A and B of OH strain of IBDV. Infectious progeny viruses were recovered in Vero cells transfected with combined transcripts of segment A and segment B of these cDNA clones. Moreover, transfection of Vero cells with full-length segment A transcript and a partial length segment B transcript derived from a partial length cDNA construct of segment B without its 3′ noncoding sequences also produced infectious virus that was almost indistinguishable from the wild-type IBDV. The 3′  noncoding sequences that were absent in the partial length cDNA construct of segment B were regenerated in the genomic RNA of the progeny infectious virus indicating the functional significance of this region in establishing a productive infection. (Abstract shortened by UMI.).

abstract: Source: Dissertation Abstracts International, Volume: 61-04, Section: B, page: 1770.

abstract: Adviser:  Frederick Kibenge.


title: The relationship between management factors, antimicrobial sensitivity and prevalence of staphylococcal mastitis pathogens in a random sample of Prince Edward Island dairy herds

contributor: Curtis, Bob (Supervisory Committee Member)

contributor: Dohoo, Ian (Supervisory Committee Member)

contributor: Donald, Alan (Supervisory Committee Member)

contributor: Kibenge, Fred (Supervisory Committee Member)

contributor: Ogilvie, Tim (Supervisory Committee Member)

contributor: Ruegg, Pam (Supervisory Committee Member)

format: 130 electronic application/pdf

subject:
Biology, Microbiology
Agriculture, Animal Pathology
Biology, Veterinary Science

abstract: This study, an investigation of coagulase positive (CPS) and coagulase negative (CNS) staphylococcal mastitis in 44 randomly selected dairy herds in Prince Edward Island (REI) had three major objectives. These are: (1) to survey dairy management factors and determine the effect of management factors on the herd prevalence of staphylococcal mastitis pathogens. (2) to survey antimicrobial sensitivity of Staphylococcus isolates from the study herds, and assess which management factors affect sensitivity of staphylococcal mastitis pathogens to these antimicrobials. (3) to determine it significant correlations exist between the prevalence of staphylococcal mastitis pathogens and their in vitro antimicrobial sensitivity.

abstract: Adoption rates of 79% and 48% for post-milking teat dipping and dry cow therapy for all cows in a herd were observed. Cloxacillin benthazine and Oxytetracyline hydrochloride were the most widely used dry cow products, on 48% and 32% of farms respectively. Seventy-eight percent of the farms used products containing beta lactams, 48% of these contained Penicillin G.

abstract: The association between the proportions of CPS or CNS sensitive to penicillin G and tetracycline in vitro and the herd prevalence were sought after taking into account farm factors using the partial correlation coefficient. No significant associations were found. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 31-04, page: 1628.


title: The relationship between the hypothalamo-pituitary-adrenal axis and the development and persistence of pancreatic islet defects in obese Zucker (fa/fa) rats

contributor: Ihle, Sherri (Supervisory Committee Member)

contributor: Ireland, W. (Supervisory Committee Member)

contributor: Tasker, Andrew (Supervisory Committee Member)

format: 161 electronic application/pdf

subject: Biology, Animal Physiology

abstract: Using isolated pancreatic islets from adult, weanling and suckling rats, the time of onset of functional changes in $\alpha\sb2$-adrenergic receptors and abnormal regulation of glycolysis in B-cells was investigated in obese fa/fa Zucker rats.

abstract: Functional changes in $\alpha\sb2$-adrenergic receptors were not observed in these studies. These studies failed to confirm the existence of a prazosin-sensitive $\alpha\sb2$-adrenoceptor previously reported in islets of fa/fa rats.

abstract: Changes in the glucokinase sensitivity to inhibition by mannoheptulose were present in isolated islets from both adult and 5 wk old, but not 3 wk old preobese fa/fa rats. Mannoheptulose inhibited glucose stimulated insulin release in a dose dependent manner in isolated islets from adult, 5 wk and 3 wk old lean rats and in 3 wk old preobese fa/fa rats.

abstract: From these studies it is concluded that when isolated islets from fa/fa rats are incubated in glucose which is within the physiological range, functional changes in the $\alpha\sb2$-adrenoceptors are not expressed. Also, the sympathetic nervous system exerts its inhibitory regulation of the pancreatic islet B-cells through $\alpha\sb2$-adrenoceptors but not $\alpha\sb1$-adrenoceptors. Insensitivity to mannoheptulose arose concurrently with the reported onset of fasting hyperinsulinemia.

abstract: The dependence on the presence of an intact hypothalamo-pituitary-adrenal axis to the development of the reduced glucokinase response to mannoheptulose inhibition was further investigated by carrying out adrenalectomy in 5 wk old lean and fa/fa rats. Adrenalectomy was found to reduce the rate of weight gain in fa/fa rats but did not affect the pancreatic islet insulin content. There was no effect of adrenalectomy on either weight gain or islet insulin content in the lean rats. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 33-01, page: 0148.

abstract: Adviser: C. Chan.


title: The relative bias in sampling estimates of production and disease parameters of caged Atlantic salmon

contributor: Long, J.R. (Supervisory Committee Member)

contributor: Thorburn, M. (Supervisory Committee Member)

contributor: Spangler, Elizabeth (Supervisory Committee Member)

contributor: Johnson, G. (Supervisory Committee Member)

format: 156 electronic application/pdf

subject:
Agriculture, Animal Pathology
Agriculture, Forestry and Wildlife
Agriculture, Fisheries and Aquaculture

abstract: The relative selection bias in dip net sampling of caged Atlantic salmon was investigated at two different stages of the production cycle. A pre-grading sample was obtained by crowding a group of fish within their cage and collecting three to five at a time in a dip net.

abstract: The mean fish weight estimated by the dip-net sampling method was significantly heavier (102 grams, p = 0.013) than that estimated by the systematic random sampling method at one site. The dip sample mean fish length was significantly shorter (.82 cm, p = 0.0001) at one site and significantly longer (0.21 cm, p = 0.044) at the other site when compared to the random sample. Condition factor was significantly greater (0.099, p = 0.0003) at one site only. Within individual cages, the dip sample estimates of means ranged from 145 grams lighter to 355 grams heavier, from 1.7 cm shorter to 0.7 cm longer, and from 0.04 units less to 0.26 units more for condition factor when compared to estimates from random samples.

abstract: Prevalence of granulomatous lesions at necropsy was significantly higher (p $<$.05) in dip samples than in systematic random samples. Lesions were also significantly associated with smaller fish in one cage (p $<$.05). (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 32-02, page: 0523.


title: The response of small mammals to habitat characteristics at different spatial scales

contributor: Teather, Kevin (Supervisory Committee Member)

contributor: Lacroix, Christian (Supervisory Committee Member)

format: 139 electronic application/pdf

subject: Biology, Ecology

abstract: The primary goal of this research was to investigate how small mammals use and interact with characteristics of their habitat, at various spatial scales. This goal was accomplished by studying the species richness and abundance of small mammals, and by assessing the movement patterns of a common small mammal, the eastern chipmunk (Tamias striatus). Trapping, using both Sherman live traps and pitfall traps, was used to determine the species richness and abundance of small mammals in various forested areas. Movement pathways of the eastern chipmunk were obtained by fluorescent powdering or spool-and-line tracking of individuals. Pathways were photographed and digitized so the movement patterns could be quantified using measures such as the fractal dimension, mean turning angle, total/net displacement, and radius of gyration. To examine how patterns of movement were affected by habitat features, these pathway quantifiers were related to various habitat descriptors. Fractal analysis was used to examine if there were spatial scales at which chipmunks showed transitions in their movement behaviour. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 42-02, page: 0518.

abstract: Advisers: Marina Silva; Sheldon Opps.


title: The river runs through it:  Evaluation of the effects of agricultural land use practices on macroinvertebrates in Prince Edward Island streams using both new and standard methods

contributor: Teacher, Kevin (Supervisory Committee Member)

contributor: Reynoldson, Trefor (Supervisory Committee Member)

contributor: Brockhouse, Charles (Supervisory Committee Member)

contributor: Alder, Peter (Supervisory Committee Member)

format: 207 electronic application/pdf

subject:
Biology, Ecology
Environmental Sciences
Biology, Limnology

abstract: Thirty-seven streams representing reference and test sites were sampled for the benthic macroinvertebrate fauna and habitat characteristics during two seasons (summer and fall) in 2001. Several reference condition approaches were used to evaluate the streams. The BEnthic Assessment of SedimenT was used to group related streams based on the macroinvertebrate community composition (which was related mostly to size characteristics of the stream). Biological (taxa abundance) and environmental characteristics were considered simultaneously to produce a prediction model for a reference condition for PEI. The model was also used to predict the kinds and abundance of various taxa that should occur in a site, based on habitat characteristics. Eleven “'test” samples (from sites which were believed to be impacted by agriculture) were then compared to the reference sites with similar habitat characteristics to assess whether their macroinvertebrate fauna matched the predictions. The same groups of sites were compared using nine biological metrics, which compare the abundance or proportions of certain taxa or groups of taxa. These methods were also used to assess the Wilmot River after a catastrophic pesticide runoff event in the summer of 2002. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0488.

abstract: Advisers:  D. Giberson; L. Hale.


title: The role of antibody during ovine lentivirus disease in experimentally infected sheep

contributor: Ikede, Basil (Supervisory Committee Member)

contributor: Kibenge, Frederick (Supervisory Committee Member)

contributor: Sims, David (Supervisory Committee Member)

format: 132 electronic application/pdf

subject:
Biology, Veterinary Science
Health Sciences, Immunology

abstract: Infection of sheep by Ovine Lentivirus (OvLV) is a significant disease throughout the world, with the exception of Australia and New Zealand.

abstract: In this study, the sera of four experimentally infected sheep were analysed over a two-year time period, with respect to neutralizing antibody (NT-Ab) titres and non-neutralizing ELISA antibodies against both the whole virus and the immuno-dominant recombinant proteins; capsid (CA), and trans-membrane peptide (TM). It was hypothesised that a further mechanism of persistence of OvLV may be mediated by interference of non-neutralizing antibodies with neutralizing antibody via conformational change of viral surface envelope proteins, which contain Nt-Ab epitopes. The postulated phenomenon of virus-obstructing antibody activity was investigated by analysis of correlation between neutralizing and non-neutralizing antibody responses (i.e. vs capsid/transmembrane), as well as by a neutralizing assay where high and low neutralizing antibody titre sera were analysed in a 1:1 mixture.

abstract: The report of an IgG, restricted antibody response in OvLV infection was investigated. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0499.

abstract: Adviser:  Arnost Cepica.


title: The role of astrocyte-dependent, Nrf2-ARE induction in flavonoid-mediated protection for primary mouse cortical cultures

contributor: Saleh, Tarek (Supervisory Committee Member)

contributor: Nelson, Caroline (Supervisory Committee Member)

contributor: Chan, Cathy (Supervisory Committee Member)

format: 100 electronic application/pdf

subject: Health Sciences, Pharmacology

abstract: Oxidative stress is proposed to have an early role in the development and progression of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Activation of the nuclear factor E2-related factor 2/antioxidant response element (Nrf2/ARE) pathway leads to increased expression of many protective antioxidant and phase II enzymes, including reduced-nicotinamide adenine dinucleotide phosphate quinone oxidoreductase (NQO1). Numerous compounds, including some phenolic antioxidants, are ARE inducers that convey neuroprotection against oxidative stress. Here, we report that kaempferol, quercetin-3-glucoside (Q3G) and quercetin significantly increased NQO1-ARE gene transcription in an ARE promoter-directed luciferase assay. In addition, kaempferol and Q3G significantly increased NQO1 enzyme activity, at 5 μM and 10 μM respectively. Pretreatment with Q3G or kaempferol provided significant protection to primary cortical cultures against a toxic concentration of H2O2 (25 μM), at 7.5-30 μM and 20 μM respectively. Overexpression of a dominant-negative version of Nrf2 (Ad-DN-Nrf2) in C57Bl6 cortical cultures abolished kaempferol-mediated protection, while an enhanced green fluorescent protein adenovirus control (Ad-EGFP) did not. Adenovirus infection occurs only in astrocytes; thus the Nrf2/ARE pathway in astrocytes contributes to kaempferol-mediated protection against oxidative stress-induced cortical culture death. Q3G-mediated protection at 7.5-10 μM is abolished by preventing ARE gene expression with dominant negative Nrf2. However, a significant loss in Q3G-mediated protection after Ad-DN-Nrf2 infection is only observed at 20 μM. This suggests that the Nrf2/ARE pathway contributes to the antioxidant efficiency of some flavonoids and confers protection to primary cortical cell cultures against oxidative stress.

abstract: Source: Masters Abstracts International, Volume: 46-03, page: 1490.


title: The role of extracurricular activities at Saint Thomas Aquinas Catholic secondary school

contributor:
Bradley, Darrell (author)
(Thesis advisor)
(Supervisory Committee Member)

format: 71 electronic application/pdf

subject: Education, Secondary

abstract: This study examined the relationship between participation in extracurricular activities and various components of students' lives at St. Thomas Aquinas Catholic secondary school in Tottenham, Ontario for the 2001/2002 academic year. Two hundred and twenty-one students were randomly selected to complete a questionnaire in order to gather data pertaining to the extracurricular activities at this school. Data analysis revealed that there was a statistically significant relationship (@ 0.05) between extracurricular participation level and school satisfaction but a statistically significant relationship could not be found for participation level and academic achievement, discipline problems, grade level or gender. It was concluded that the extracurricular program is meeting the needs of the students but a broader range of activities is suggested.

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0387.

abstract: Adviser:  Alexander (Sandy) MacDonald.


title: The role of gender in staying smoke-free in adolescence: Using a theory of planned behavior approach

contributor:
Diamond, Heather C. (author)
Murnaghan, Donna (Thesis advisor)
Blanchard, Chris (Thesis advisor)
(Supervisory Committee Member)

format: 149 electronic application/pdf

subject:
Psychology, Behavioral
Health Sciences, Public Health
Education, Health

abstract: Adolescents in grades 5 through 9 (ages 10-15) are most likely to first experiment with tobacco use. The ability to identify factors that contribute to adolescent smoke-free behaviour is critical to tobacco control initiatives. Further, examining potential gender differences in smoke-free behaviour may be beneficial to identifying and supporting smoking prevention initiatives tailored to male and female adolescents.

abstract: This thesis is a secondary analysis of data collected in Prince Edwards Island intermediate schools. Regression analyses were used to determine whether the theory of planned behavior (TPB) explained significant variation in smoke-free intentions and behavior among adolescents, and whether any of these relationships were moderated by gender. The relationship of gender-specific beliefs as they inform being smoke-free were also examined. Two samples of intermediate school students (500 students, grades 7-9) were analyzed and compared. Students completed a theory of planned behavior questionnaire to identify their beliefs about staying smoke free; thirty days later, students completed a follow-up questionnaire which measured actual smoke-free behavior.

abstract: Study results supported the predictive ability of the TPB, with self-efficacy emerging as a significant predictor of smoke-free intentions for all adolescents. Some significant gender differences were found; the smoke-free intentions of male students were significantly related to grade level, while those of females were not. Further, smoke-free behaviour was significantly more strongly predicted by PBC for some female students than for males. One major application of the findings, given areas of divergence and of similarity with earlier studies, is the need for further research on gender differences in remaining smoke-free.

abstract: Source: Masters Abstracts International, Volume: 47-06, page: 3154.


title: The role of ryanodine receptors in a mouse model of Alzheimer disease

contributor: Gottschall-Pass, Kathy (Supervisory Committee Member)

contributor: Robertson, George (Supervisory Committee Member)

contributor: Zidichouski, Jeff (Supervisory Committee Member)

format: 162 electronic application/pdf

subject:
Biology, Molecular
Biology, Neuroscience
Biology, Physiology

abstract: By the year 2020 approximately 1.5 million Canadians will suffer from a form of aging-related dementia, with the majority diagnosed with Alzheimer disease (AD). Current cost estimates suggest that by the year 2025 treatment for neurodegenerative disease will cost the Canadian health care system approximately 50 billion dollars per year. Thus, there is an urgent need for discovery of new therapeutic targets that will delay the onset or reduce the devastating consequences of AD.

abstract: The accumulation of amyloid-beta (Aβ) peptide and disruption of cytosolic calcium (Ca2+) levels are pathological hallmarks of neuronal dysfunction in the AD brain. Studies outlined in this thesis focus on the ryanodine receptors (RyRs); how they regulate cytosolic Ca2+  levels and contribute to the dysfunction of AD neurons. RyR type 3 (RyR3) expression was up-regulated when exposed to Aβ fragment 1-42 (Aβ42) and in neurons from transgenic (Tg)CRND8 mice; a model of AD. Ca2+ imaging experiments demonstrated that RyR3 contributed to the increased cytosolic Ca2+ response of Tg to glutamate and ryanodine compared to neurons from nonTg littermates. However, Tg neurons were no more susceptible to AD-related stressors such as glutamate, hydrogen peroxide, staurosporine and in vitro aging. Instead, the suppression of RyR3 up-regulation in Tg neurons by short-interfering RNA sensitized Tg neurons to death after aging in vitro for 18 days. When TgCRND8 mice were crossed with RyR3 knock-out (RyR3-1-) mice, they were sensitized to premature, spontaneous death possibly by severe seizure. TgCRND8/RyR3-1- showed increased susceptibility to more severe, pharmacologically-induced seizure compared to littermates. These data suggest a role for RyR3 in the maintenance of neuronal viability and suppression of hyperexcitability and death in TgCRND8 mice. Further research is required to detemine if RyR3 up-regulation is an optimal therapeutic target for the treatment of AD.

abstract: Source: Dissertation Abstracts International, Volume: 71-08, Section: B, page: 4670.


title: The summer -fall slump:  Seasonal variation in average daily milk production in Prince Edward Island, Canada

contributor: Dohoo, Ian (Supervisory Committee Member)

contributor: Hennessey, Sean (Supervisory Committee Member)

contributor: Leslie, Ken (Supervisory Committee Member)

contributor: McNiven, Mary (Supervisory Committee Member)

contributor: Miller, Lisa (Supervisory Committee Member)

format: 262 electronic application/pdf

subject: Economics, Agricultural

abstract: Average test-day milk production in Prince Edward Island, Canada, was observed to follow a pronounced and consistent seasonal pattern, with peak and nadir production occurring in June and November, respectively. It was also observed that there was substantial herd-to-herd variation in the seasonal patterns of milk production, with some herds maintaining seasonally consistent average milk yields and others exhibiting a decline in average test-day milk yield of approximately fifty percent during the summer and fall months. There was also controversy surrounding the association of economic performance with seasonal variation in average test-day milk yield.

abstract: During the years 1990 to 1994, the average test-day production in November was 74.5% of that observed in June for all Prince Edward Island dairy herds. Herds tended to show similar patterns of milk production from one year to the next.

abstract: An income-over-feed-cost (IOFC) analysis was used to determine the relationship between seasonal variation in milk production and economic performance. A positive, linear relationship was found between seasonal patterns of production and IOFC, with seasonally consistent herds demonstrating higher IOFC than herds with marked seasonal variability in production. On average, for every 10 percent reduction in average test-day milk yield from June to November, IOFC of $215.32 per cow per annum was forfeited.

abstract: Delphi and conjoint analysis techniques were used to obtain estimates of the expected increase in pasture dry matter yield resulting from the use of various pasture management techniques. These two methods yielded results that were highly correlated when combined at the field level (R2 = .89) and that demonstrated good agreement with the appropriate data in the literature.

abstract: In-depth examinations of the relationship between nutrition, body condition score, internal parasite exposure and the seasonal pattern of milk production were completed before using multivariable modeling techniques to explain the inter-herd variability in seasonal variation in average test-day milk production in PEI. In addition, information on herd reproductive performance and herd management data were included in the multivariable models. The models explained a significant proportion of the between-herd variability in the seasonal patterns of milk production, and were found to be robust and reliable after thorough examination. A number of factors were found to be statistically associated with the seasonality of herd average test-day milk production. In the most parsimonious model these included herd level factors that measured the reproductive performance. (seasonal difference in days-in-milk), the internal parasite exposure levels (bulk tank milk Ostertagia ostertagi optical density values) and the nutritional management during the summer (kilograms of supplementary, non-forage DM cow−1 day−1 ). To rank the variables as to their relative importance, the regression coefficients were multiplied by the interquartile range of the observed values. Using this technique, reproductive performance and Ostertagia ostertagi  optical density values were shown to have a similar impact on the seasonal pattern of milk production in a herd, whereas in absolute terms the daily amount of non-forage dry matter per cow had a marginally lesser effect.  (Abstract shortened by UMI.).

abstract: Source: Dissertation Abstracts International, Volume: 61-03, Section: B, page: 1141.

abstract: Adviser:  Ian Dohoo.


title: The synthesis of chiral catalysts for olefin polymerization

contributor:
Song, Liping (author)
Etkin, Nola (Thesis advisor)
(Supervisory Committee Member)

format: 110 electronic application/pdf

subject: Chemistry, Organic

abstract: Olefin polymerization is an extremely important industrial application of catalysis. A polymer's properties depend to a large extent on its stereoregularity, so the ability to control the stereochemistry of the polymerization is important.

abstract: Chiral catalysts are known to produce stereoregular polymers through enantiomorphic site control, in which a chiral ligand attached to the metal has a greater influence on the stereochemistry of the inserting monomer into the polymer chain than influence of the polymer chain itself. If the catalyst is chiral, then it is possible that the products will also be chiral. A synthesis of chiral catalysts from commercial L-phenylalanine which is a common amino acid that contains a built-in chiral center is described. This chiral center is maintained throughout the course of the reactions and is the chiral center of the bridging ligand. The amino acids were transformed into chiral ligands, and then attached to a metal to make the catalysts. We hope that, like chiral group IV metallocences which have been employed as stereoselective catalysts for olefin polymerizations. Our catalytic complex will control the stereochemistry of the polymer.

abstract: We tried to follow route 1 to make chiral constrained geometry catalyst, however it was unsuccessful. We had more success following route 2 to make chiral biamide ether complexes.*.

abstract: *Please refer to dissertation for diagrams.

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0538.

abstract: Adviser:  Nola Etkin.


title: The transition of students with disabilities from high school to post secondary activities: A Prince Edward Island perspective

contributor:
Costa, Frank M. (author)
Timmons, Vianne (Thesis advisor)
(Supervisory Committee Member)

format: 143 electronic application/pdf

subject: Education, Special

abstract: This qualitative study explored the transition process for students with disabilities in Prince Edward Island, Canada when they transitioned from high school to post secondary activities. Information was obtained from 2 questionnaires. One questionnaire was submitted to each of the 12 high schools in Prince Edward Island. A second questionnaire was submitted to Disability Support Workers in the provincial Department of Social Services and Seniors. A third data collection was obtained from a focus group interview of parents of students with disabilities who had transitioned from high school. Although there are elements and pockets of some form of transitional planning occurring in educational and social services jurisdictions across Prince Edward Island, it is apparent from the research findings that it is not consistent. In fact, there is an absence of neither a common process nor a common practice when transitional plans are developed for students with disabilities.

abstract: Source: Masters Abstracts International, Volume: 46-03, page: 1229.


title: Together we're better: The process of collection development in a Prince Edward Island elementary school library

contributor: Gabriel, Martha (Supervisory Committee Member)

format: 124 electronic application/pdf

subject:
Library Science
Education, Elementary

abstract: This study explored the collection development process in an elementary school in Prince Edward Island, Canada. The case study employed several data gathering tools: collection mapping, reflections of School Library Committee members, circulation analysis, and the researcher's reflective journal. The findings are shared in two formats: a month-by-month presentation analysis of key themes and an analysis according to the Van Orden collection program model. The vital position that collection development plays in the leadership role of the teacher-librarian was validated through this action research. The collaborative approach used resulted in several tangible benefits to the school library program, including a greater awareness by staff of the complexity of the teacher-librarian's role and an understanding of the value of having a school library committee for developing the school library program. Recommendations for possible actions, as well as suggestions for establishing supports to fully implement these recommendations are presented.

abstract: Source: Masters Abstracts International, Volume: 41-02, page: 0357.

abstract: Adviser: Ray Doiron.


title: Towards home: Creating a place for holistic healing in wellness promotion

contributor:
Muirhead, Enid Louise (author)
Vokey, Daniel (Thesis advisor)
Brookers, Anne-Louise (Thesis advisor)
Gabriel, Martha (Thesis advisor)
(Supervisory Committee Member)

format: 243 electronic application/pdf

subject:
Health Sciences, Public Health
Education, Health

abstract: The purpose of this study was to explore the lived-experience of nurses engaged in holistic energy-field healing practice with a view to proposing the potential role of such practitioners in integrative wellness promotion practice within an emerging Primary Health Care environment. The specific research question was ‘Is it possible that solutions exist that we have not adequately examined?’

abstract: The five nurses interviewed for this research used energy-field modalities in wellness promotion practice, including Reflexology, Reiki, Therapeutic Touch, Acupuncture, Nambudripad's Allergy Elimination Technique, prayer, and bio-energetic therapy. A qualitative reflexive methodology of storytelling and mandala drawing was chosen to reflect the wholeness of the transformative process experienced by participants in the transition from the biomedical to the holistic world view. Reflexive methodology provides for situating the data within the context of personal histories, in order to make connections between personal lives and personal careers, and to understand personal influences on professional practice. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 42-02, page: 0386.

abstract: Advisers: A. L. Brookes; M. Gabriel.


title: Transformative learning through professional development in conflict resolution training

contributor: Timmons, Vianne (Supervisory Committee Member)

format: 112 electronic application/pdf

subject: Education, Adult and Continuing

abstract: This qualitative study explored the experiences of 7 individuals who participated in conflict resolution training at the Centre for Conflict Resolution Studies at the University of Prince Edward Island. An open-ended interview approach was employed to gather the data. During the in-depth interviews, each participant reported that they perceived a significant change in their perspectives towards conflict and conflict resolution after participating in various courses. Three participants also reported changes in their perspectives towards themselves as individuals. Each of the participants described how their participation in the conflict resolution training impacted both their personal and professional lives. The participants reported that as they applied their strengthened conflict resolution skills, they were able to make positive changes in their lives, such as improving their performance at work and building stronger personal relationships. In addition, 4 of the participants believe that they have expanded their career opportunities as a result of what they learned. Recommendations are made for future research in the area of conflict resolution training for adults. Personal reflections of the researcher conclude the study.

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0365.

abstract: Adviser:  Vianne Timmons.


title: Transmission and pathogenesis of Piscirickettsia salmonis in Atlantic salmon (Salmo salar)

contributor: Markham, R.J. Frederick (Supervisory Committee Member)

contributor: Speare, David (Supervisory Committee Member)

contributor: Wright, Glenda (Supervisory Committee Member)

contributor: Jones, Simon (Supervisory Committee Member)

contributor: Cawthorn, Rick (Supervisory Committee Member)

format: 180 electronic application/pdf

subject:
Biology, Microbiology
Agriculture, Animal Pathology
Agriculture, Fisheries and Aquaculture

abstract: Piscirickettsia salmonis is the etiological agent of Salmonid Rickettsial Septicaemia (SRS), a major disease affecting several species of salmonids cultured in salt water in Southern Chile. This organism to grow and produce a characteristic cytopathic effect (CPE) in several fish cell lines but not Lepomis macrochirus R. (BF-2). In a first experiment, Chinook salmon embryo (CHSE-214) and BB cells were inoculated with P. salmonis, incubated at $15\sp\circ$C for 78 days, and studied by light microscopy (LM) and transmission in CHSE-214, and after 45 days post-infection in BB cell line. Transmission electron microscopy (TEM) examination of BB cells after 78 days post-infection, revealed P. salmonis within membrane-bound vacuoles or free within the cytoplasm and the extracellular space. These results indicate that BB cells are susceptible to infection with P. salmonis but exhibit a slower pattern of invasion. In a second experiment, two susceptible Atlantic salmon fibroblasts (ASF) and CHSE-214, and one non-susceptible (BB) fish cell lines were infected with P. salmonis and studied by LM and TEM at 1, 7, and 14 days post infection. Results showed differences in the appearance of CPE and in the intracellular infection mechanisms of the pathogen among cell lines. Infected CHSE-214 cells had vacuoles containing P. salmonis whereas ASF cells had empty vacuoles and BB cells had empty vacuoles and P. salmonis free in the cytosol. An in vivo experiment was designed to compare three routes of inoculation (oral, gill surface and intraperitoneal), and to study the effect of physical contact as a risk factor in the horizontal transmission of SRS in Atlantic salmon raised in fresh water. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 35-03, page: 0757.

abstract: Adviser: Carmen Fuentealba.


title: Transmission factors for microsporidial gill disease caused by Loma salmonae

contributor: Markham, F. (Supervisory Committee Member)

contributor: Conboy, G (Supervisory Committee Member)

contributor: Rainnie, D. (Supervisory Committee Member)

contributor: Ikede, B. (Supervisory Committee Member)

format: 230 electronic application/pdf

subject: Biology, Microbiology

subject: Biology, Veterinary Science

subject: Agriculture, Fisheries and Aquaculture

abstract: Loma salmonae causes microsporidial gill disease (MGD) in farmed Pacific salmonids, Oncorhynchus spp., resulting in respiratory distress, secondary infections and often mortality. The infection occurs in the gills and to a lesser extent in other vascularized tissues with a final development stage of a spore-laden xenoma within the endothelial and pillar cells of the gill. The overall research goal was to identify important host, parasite and environmental factors associated with the transmission of L. salmonae in rainbow trout (RBT).  Environmental factors. Water temperature is considered to be an important environmental variable in the transmission of many fish diseases. Using a cohabitation challenge model, RBT held at 19°C had the least number of days to the development of branchial xenomas compared to fish held at either 11° and 15°C and the latter two temperatures groups showed similar xenoma onset rate. A subsequent trial revealed that water temperature affects xenoma clearance and recovery time, so that as the water temperature increased, the time required for the dissolution of all branchial xenomas decreased.  Host factors. Investigations under the domain of host factors centered on the effects of various feeding rates, the dependency of fish size at the time of exposure and further studies investigating the efficacy of monensin therapy. Although feeding rate did not alter the onset or resulting intensities of branchial xenomas, fish size was found to be a significant factor. Small RBT (17 to 23 g) had significantly faster rate of xenoma development and increased xenoma intensity with the median onset time approximately 1 week sooner compared to the 2 larger size groups. Another host factor considered was the potential use of monensin therapy to treat MGD by investigating the minimum dose and treatment time required for therapeutic success. Pathogen factors . The third domain of the disease triad contains factors that directly involve the pathogen. A novel challenge model using only effluent water revealed that L. salmonae was transmitted to naive RBT without the need for physical contact with infectious fish. (Abstract shortened by UMI.).

abstract: Source: Dissertation Abstracts International, Volume: 65-09, Section: B, page: 4453.

abstract: Adviser: David Speare.


title: Traumatic brain injury:  Challenges and considerations for the school

contributor:
Deglan-Gallant, Tara (author)
Timmons, Vianne (Thesis advisor)
(Supervisory Committee Member)

subject: Health Sciences, Rehabilitation and Therapy

subject: Education, Special

subject: Education, Teacher Training

abstract: This qualitative study profiles two families on Prince Edward Island who have a child with a traumatic brain injury (TBI) currently in the school system. It explores the changes that the students, their families and their school communities experienced during their recovery and reintegration to school. The purpose of this research was to determine the challenges for a school when a child who has incurred a TBI returns to the classroom, and to provide school personnel with considerations to maximize a successful transition from home to school.

abstract: The research is based on a number of in-depth interviews with parents, medical professionals and school personnel. During the course of the interviews, a number of issues evolved which are consistent with findings from a review of the literature. The results of acquiring a TBI affects all aspects of the individual's life—cognitively, physically, behaviorally, and socially. These changes have a significant impact on the home, the school and the social environment of the child and need to be considered by school personnel during the reentry process. Key elements to consider for successful reentry planning include: educating school personnel on the extent of the injury and how it has impacted the child; collaborating with medical professionals, parents and the student to share information and provide a support team; planning for realistic and flexible goals and appropriate interventions; preparing students for the child's return in order to establish a peer support system; and seeking additional support both within and outside the school system to address the individual needs of the child. If schools use the guidelines outlined above to prepare for a child's return to school, they can become well equipped to provide effective services to students with a traumatic brain injury.

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0391.

abstract: Adviser:  Vianne Timmons.


title: Triploid production in Mytilus edulis

contributor: Spreare, David J. (Supervisory Committee Member)

contributor: Spangler, Elizabeth (Supervisory Committee Member)

contributor: Gallant, Richard (Supervisory Committee Member)

format: 116 electronic application/pdf

subject:
Biology, Genetics
Agriculture, Fisheries and Aquaculture

abstract: Prince Edward Island (PEI) is a leader in North America in the production of blue mussels Mytilus edulis. Concerns in the PEI mussel aquaculture industry over poor product quality during, and immediately after the spawning period have prompted research on triploid mussels. Triploid shellfish are sterile and retain quality during the spawning period. The aim of this research was to develop a method to produce triploids and to test performance of them versus normal diploids under culture conditions.

abstract: The first goal of this research was to develop a triploid induction technique and optimize the technique so it could apply to commercial production of seed. This involved investigating the timing of meiotic events in the local blue mussel. The resulting description of meiotic events was used to develop a series of suitable treatment time windows for testing in the optimization of the triploid inducing technique. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 41-02, page: 0489.

abstract: Adviser: Jeff Davidson.


title: Undeniable attraction: The geopolitical relationship between the great powers and small islands, 1660--2009

contributor:
Walker, Jordan (author)
Bartmann, Barry (Thesis advisor)
(Supervisory Committee Member)

format: 273 electronic application/pdf

subject: History, Modern

subject: Political Science, General

subject: Political Science, International Law and Relations

abstract: This paper examines the critical relationship between the great powers and small islands in a geopolitical context. The paper introduces a theory, namely, Small Island suction effect, and asserts that this geopolitical theory is a special dynamic that can exist between small islands and the great powers. For this suction effect to take place it is necessary for a small island to contain at least one of five identifiable components of interest that are magnetic vis-à-vis great powers. The five components of interest to great powers in relation to small islands are geopolitical position, weakness and small size, great power competition, prized resources, prestige and honour. The overall purpose of this paper is to attempt to prove that small island suction effect does in fact exist in the international system. To help prove this theory's existence we use history as our backdrop and draw on empirical evidence and sound argumentation in conjunction with the political theory of Realism, all to facilitate this process of theory substantiation. We examine five different great power systems that encompass all the different types; small island suction effect is evident in unipolar, bipolar, and multipolar systems. The genesis point in great power systems history is 1660 and the end point is the present day. Many different geopolitical theatres are explored in an effort to demonstrate this theory's near geographic universality. This geopolitical theory is most active in a multipolar system and less active in a unipolar and bipolar system. The component of interest that most often triggers this suction effect is geopolitical position be it for defensive or offensive purposes in relation to the great powers. Furthermore, Sir John Halford Mackinder's Heartland Theory is refined placing an emphasis on great powers competing for or being sucked in to small islands rather than just the World-Island.

abstract: Source: Masters Abstracts International, Volume: 47-06, page: 3278.


title: University students' experience in on-line courses

contributor:
MacSwain-Jackson, Virginia (author)
Gabriel, Martha (Thesis advisor)
Liu, Xiufeng (Thesis advisor)
(Supervisory Committee Member)

format: 150 electronic application/pdf

subject: Education, Technology of

abstract: The delivery of courses over the Internet (on-line) is becoming very popular. On-line courses are appearing for industry, general interest and for education allowing university students to take courses on-line. Universities now offer complete degree programs on-line. Numerous university instructors now use some form of on-line learning in the delivery of their courses. This study explores the experience of students taking on-line courses at the University of Prince Edward Island (UPEI). This research will assist instructors at UPEI in the development and delivery of their on-line courses, whether fully on-line or web-assisted, so that students' learning experiences will be enhanced.

abstract: This study used both qualitative and quantitative methods to explore students' responses to their on-line learning experience at UPEI. Questionnaires were e-mailed to all students enrolled in seven on-line courses offered at UPEI, with a return rate of 33%. Semi-structured qualitative interviews were held with students and course instructors. The results of the study indicate that both instructors and the students alike believed that the students had a positive learning experience while taking their on-line course.

abstract: The study revealed important benefits of on-line learning for both students and instructors including flexibility, convenience, accessibility, interactivity, and effective communication via bulletin boards. The findings also indicated that students and instructors believe in the importance of on-line course offerings at UPEI. During the time frame of this study, the majority of students enrolled in on-line courses at UPEI were students enrolled in a co-op program. The results of this study should give students insight into what to expect when enrolling in an on-line course and provide instructors with valuable information regarding the development of on-line courses which will enhance the students' learning experiences.

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0392.

abstract: Adviser:  Martha Gabriel.


title: Uptake and tissue distribution of lipid vesicles (liposomes) after intraperitoneal injection into rainbow trout (Oncorhynchus mykiss)

contributor: Markham, R.J. Frederick (Thesis advisor)

contributor: Daoust, Pierre-Yves (Supervisory Committee Member)

contributor: Johnson, Gerry (Supervisory Committee Member)

contributor: Sims, David (Supervisory Committee Member)

format: 120 electronic application/pdf

subject:
Biology, Animal Physiology
Biology, Veterinary Science
Agriculture, Fisheries and Aquaculture

abstract: The uptake and tissue distribution of liposomes after intraperitoneal injection into rainbow trout was investigated. In all cases uptake was concentrated mainly in the spleen and kidney, the primary centers of the mononuclear phagocytic system in fish. Total tissue uptake of neutral and negatively charged multilamellar vesicles (MLV) was similar, although the negatively charged liposomes had a different distribution among tissues. Uptake of neutral MLV by spleen and kidney was proportional to administered doses from 0.18 to 3.6 mg of total lipid as liposomes. When compared to large unilamellar vesicles (LUV), the uptake of MLV was relatively poor. The distribution of LUV among tissues was similar to that of the MLV. The use of fluorescein-labelled LUV demonstrated that these structures gain access to the circulation as free particles.

abstract: Pharmacokinetic studies of LUV and small unilamellar vesicles (SUV) in rainbow trout revealed that SUV reached higher concentrations in most tissues than the LUV and remained high for a longer period of time.

abstract: A comparison was made between cholesterol as a lipid phase radiolabel and inulin as an aqueous phase radiolabel for liposome distribution studies in fish. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 30-03, page: 0662.


title: Study of an outbreak of off-flavours in bulk -tank milk

contributor: Gottschall-Pass, Katty (Supervisory Committee Member)

contributor: McNiven, Mary (Supervisory Committee Member)

contributor: Spangler, Liz (Supervisory Committee Member)

contributor: Keefe, Greg (Supervisory Committee Member)

contributor: Gao, Leigh (Supervisory Committee Member)

format: 239 electronic application/pdf

subject: Agriculture, Food Science and Technology

subject: Health Sciences, Public Health

subject: Biology, Veterinary Science

abstract: Off-flavours in milk can be classified using the following general categories: oxidized flavour, feed flavour, rancidity, and other flavours (e.g., unclean, malty, salty, flat or chemical). Off-flavours in milk occur at a low incidence in all milk-producing areas of Canada, with “outbreaks” occurring periodically in certain localities for no clearly defined reason. However, in the late 1990s, the incidence of off-flavours in bulk-tank milk was relatively high in Prince Edward Island (PEI). From the dairy company records it appeared that about 50/330, or 15% of herds, were affected during the winter season of 1999–2000. This presented a major economic problem for producers and dairy industry personnel, and attracted a degree of unwelcome media attention in PEI.

abstract: To evaluate the reliability of the method used for identifying off-flavours in milk, a sensory study was carried out with a panel of four milk-tank operators, who constituted the milk flavour quality control personnel. Results showed that the panelists had satisfactory agreement in differentiating off-flavoured milk from milk of good quality. The inter-panelist agreement ranged from substantial (Kappa statistic > 0.61) to almost perfect (Kappa statistic > 0.81), whereas the intra-panelist agreement range was moderate (Kappa statistic > 0.41) to almost perfect, suggesting that in the absence of a more objective diagnostic tool, a panel of trained milk graders was appropriate for the monitoring of the flavour quality of bulk-tank milk.

abstract: Results from clustering analyses revealed that this outbreak had not only a seasonal pattern, but also a limited geographical distribution with cases concentrated mostly in intensive dairy farming regions (Queens and Prince counties), and most importantly, a spatial-temporal pattern that usually peaked during fall–early winter months (September to January). Three high-rate space-time clusters (two composed of herds that experienced feed off-flavour and one composed of herds with rancid off-flavour) and two low-rate (areas with low rate of off-flavour occurrence) were identified. It appeared that high-rate clusters tended to receive more precipitation than low-rate clusters during the clustered time frame; temperature data were not as conclusive. (Abstract shortened by UMI.).

abstract: Source: Dissertation Abstracts International, Volume: 65-09, Section: B, page: 4454.

abstract: Adviser: Jeff Wichtel.


title: Supporting mother-infant relationships affected by intimate partner violence in Prince Edward Island: A pilot project

contributor: Critchley, Kimberley (Supervisory Committee Member)

contributor: McLellan, Debbie (Supervisory Committee Member)

format: 131 electronic application/pdf

subject: Psychology, Social

subject: Health Sciences, Public Health

subject: Psychology, Clinical

subject: Sociology, Individual and Family Studies

abstract: Purpose. The purpose of this research was to explore the relationships between mothers and infants exposed to intimate partner violence and to investigate its impact on such relationships; to address gaps in literature as there also appears to be a lack of research that explores the association between mother-infant relationships and infant development in families affected by intimate partner violence; and to identify the support needs, resources, barriers to support, and preferences for support intervention that promote mother-infant relationships, from the perspectives of mothers affected by intimate partner violence.

abstract: Setting/Participants. Three Prince Edward Island mothers with children less than 36 months at time of interview, who have been affected by intimate partner violence.

abstract: Methodology. Qualitative research methods were employed in this pilot project. Face-to-face, semi-structured interviews were conducted with participants.

abstract: Results/Conclusions. All three participants reported changes in their infants as a result of being exposed to intimate partner violence. Some of these changes were more significant than others. Two of the three participants believed that the mother-infant relationship was greatly affected by intimate partner violence, while one participant claimed that it had no effect on her relationship with her infant. The participants expressed a lack of support services for mothers affected by intimate partner violence in Prince Edward Island and identified their abusers as their main barrier in accessing the available support, along with transportation, finances, and lack of knowledge of support resources.

abstract: Source: Masters Abstracts International, Volume: 46-03, page: 1337.


title: Suppression of potato early blight (in situ) and germination of Alternaria spp. Conidia (in vitro) with strobilurin fungicides

contributor: Lacroix, Christian (Supervisory Committee Member)

contributor: Coffin, Robert (Supervisory Committee Member)

contributor: Peters, Rick (Supervisory Committee Member)

format: 101 electronic application/pdf

subject: Agriculture, Plant Pathology

abstract: Early blight, caused by Alternaria solani Sorauer, is a ubiquitous disease that may limit potato yield. Adequate crop fertility and appropriate fungicide applications usually retard development of this disease. Strobilurin analogs, such as azoxystrobin, represent a novel highly selective group of fungicides that inhibit mitochondrial respiration in many phytopathogenic fungi. The objectives of this research were: (1) to ascertain the efficacy of azoxystrobin and pyraclostrobin, in terms of potato early blight control and enhanced yield and quality, by comparing them to a conventional fungicide program, (2) to determine if potatoes treated with these two strobilurin chemicals require reduced nitrogen (N) fertilizer inputs, and (3) to verify the in vitro sensitivity of  A. solani isolates from PEI to azoxystrobin.

abstract: Results from this study indicated that both strobilurin products were linked to significantly higher biological yields for Russet Burbank in 2003 and Shepody in 2004 when compared to plots receiving no strobilurin fungicides. In 2003, no early blight symptoms developed despite artificial inoculation. Thus, in the absence of early blight infection, these increases in yield may be attributed to the physiological and developmental alterations that strobilurin products have on treated plants. No significant differences in biological yield based on N fertility were observed.

abstract: In 2004, defoliation induced by artificial inoculation was visually apparent in the controls, while symptoms did not develop in strobilurin-treated plots. For this reason, the significant yield increases observed in the Shepody plots may be attributed not only to the beneficial effects of strobilurins, but also to the control of early blight. In addition, the severity of early blight was low at both rates of N fertility in azoxystrobin and pyraclostrobin plots in 2004. Growers, therefore, may subsequently lower N inputs without compromising early blight control.

abstract: Upon examination of the 2004 Russet Burbank check plots, there was an obvious N fertility effect with the higher rate having a reduction in foliar disease severity. Furthermore, the artificial inoculation study revealed that Russet Burbank control plots had a lower disease severity rating compared to the Shepody controls.

abstract: Isolates of A. solani and A. alternata, causal agent of potato brown spot, were collected in 2003 and 2004 from several potato growing areas throughout PEI. A spore germination assay was used to determine the baseline in vitro sensitivity of these two pathogen populations to azoxystrobin. EC50 values ranged from 0.002-0.022 μg/ml for the 17 A. solani isolates tested, while the values for the 23 A. alternata isolates tested ranged from 0.001-0.028 μg/ml. These values were much lower than the EC50 value of 0.258 μg/ml that was determined for a known insensitive isolate from North Dakota, US - an area where widespread use of azoxystrobin has caused a shift in sensitivity.

abstract: Source: Masters Abstracts International, Volume: 45-03, page: 1341.


title: Swine productivity and economic efficiency

contributor: Curtis, Bob (Supervisory Committee Member)

contributor: Ogilvie, Tim (Supervisory Committee Member)

contributor: Spangler, Elizabeth (Supervisory Committee Member)

contributor: Morely, Randy (Supervisory Committee Member)

contributor: O'Rourke, Bob (Supervisory Committee Member)

subject: Engineering, General

abstract: Source: Masters Abstracts International, Volume: 40-07.


title: Synthesis and characterization of electroactive polymers and intercalated nanocomposites

contributor: Smith, Kevin (Supervisory Committee Member)

contributor: Haines, Robert (Supervisory Committee Member)

format: 100 electronic application/pdf

subject: Chemistry, Inorganic

abstract: The intercalation chemistry of molybdenum trioxide (MoO3), tin disulfide (SnS2) and graphite oxide (GO) has been investigated. Poly[oxymethylene(oxyethylene)] (POMOE) and poly[oligo(ethylene glycol) oxalate] (POEGO) have been completely inserted into the layered host of commercially available MoO3 by exploiting the swelling properties of its lithiated phase. On the other hand, partial intercalation of POMOE and POEGO into lithiated tin disulfide was obtained. The encapsulation of POMOE in the graphite oxide layered system was found to be complete. The new intercalated nanocomposites were characterized by XRD, TGA and elemental analysis.

abstract: A simple route for the synthesis of poly[bis-(methoxy ethoxy) phosphazene (MEEP) was developed and the product was characterized by NMR spectroscopy. Poly(dichlorophosphazene) (PDCP) has been synthesized by simple modification of the literature procedure. Synthesis of a new poly phosphazene substituted material was achieved by replacing chlorine atoms from the PDCP backbone with polyaniline. This new material was characterized by NMR spectroscopy.

abstract: Source: Masters Abstracts International, Volume: 44-03, page: 1372.


title: Synthesis and characterization of pendant arm macrocycles and their transition metal complexes

contributor:
Zhang, Nelson (author)
Haines, Robert (Thesis advisor)
Liu, Michael (Thesis advisor)
(Supervisory Committee Member)

format: 129 electronic application/pdf

subject: Chemistry, Inorganic

abstract: A series of pendant arm macrocycles (PAMs) based on 1,4,8,11-tetraazacyclo-tetradecane (cyclam) have been synthesized and characterized by NMR and X-ray crystallography for aromatic and aliphatic arms. Aromatic halides readily form tetra substituted PAMs while aliphatic halides preferentially form 1,8-disubstituted ones.

abstract: Copper(II) complexes of certain PAMs have been made and characterized by X-ray crystallography. For the aliphatic PAMs, both Cu(II) and Ni(II) complexes have been formed, and redox kinetics for the Ni(II) complexes have been measured. The effect of steric bulk of the PAMs on electron transfer from Ni(III) centers using an outer sphere reductant has been examined.

abstract: A series of diazirines and diazo compounds used for carbene generation have been synthesized. Several attempted syntheses of PAMs by means of carbene insertion into N-H bonds of cyclam, nucleophilic addition of cyclam to C 60, and alkylation of cyclam were unsuccessful due to steric effects.

abstract: Source: Masters Abstracts International, Volume: 43-02, page: 0537.

abstract: Adviser:  Robert Haines.


title: Synthesis and characterization of surface modified chitosan with polyaza macrocycles

contributor:
Miller, Kimberly J. (author)
(Thesis advisor)
(Supervisory Committee Member)

format: 2009 electronic application/pdf

subject:
Chemistry, Organic
Chemistry, Polymer

abstract: There is much interest in the use of biopolymers for potential commercial applications based on their relative abundance and low cost. Chitosan, derived from the deacylation of chitin, in turn obtained from crustacean shells, has been shown to have potential uses in drug delivery, phosphate binding in dialysis patients and as a filter for waste effluent containing heavy metal ions. However, the binding capacity of the biopolymer is greatly dependent on pH and ions only weakly sorb onto the surface.

abstract: Polyazamacrocycles are well known to complex a wide range of metal ions. Hence our goal in this work is to derivatize chitosan using tetraazamacrocycles, with the aim of developing modified biopolymers that may exhibit strong and selective binding for both transition metal ions and phosphate (the latter is important in the treatment of hyperphosphataemia).

abstract: We have synthesized a series of pendant arm macrocycles based on cyclam (1,4,8,11-tetraazacyclotetradecane) and tetA (meso-5,5,7,12,12,14-hexamethy1-1,4,8,11-tetraazacyclotetradecane), that bear pendant bromoalkyl groups. These have been used as precursors to derivatize chitosan. Characterization has been afforded by ATR-FTIR, TGA, H-1 NMR, and XRD.

abstract: Source: Masters Abstracts International, Volume: 47-06, page: 3604.


title: Synthesis of DTT analogues and applications of DTT and immobilized DTT

contributor: Gottschall-Pass, Kathy (Supervisory Committee Member)

contributor: Linkletter, Barry (Supervisory Committee Member)

contributor: Banks, Jeffrey (Supervisory Committee Member)

format: 109 electronic application/pdf

subject: Chemistry, Organic

abstract: The work involved in my research project is sponsored by an Industrial NSERC Scholarship and so is centred around the interests of the sponsoring company, BioVectra™ dcl. As dithiothreitol, or DTT, is one of BioVectra™ dcl's major products, they were interested in new methods of synthesis and new applications for DTT analogues. The aim of the work was to find more economical methods of synthesis of DTT isomers than those currently used by BioVectra™ dcl, as well as to find new applications for it.

abstract: The first part of the project was to find new ways to make dithiothreitol. Two different methods were tried, both from new starting materials. The challenge was the synthesis of these starting materials.

abstract: The second part of the project was the synthesis of another possible starting material, butadiene diepoxide. It would be prepared by the oxidation of butadiene.

abstract: The focus of the project was then changed to finding new applications for DTT and applications for new products being made by BioVectra dcl. These new products were all polymer-supported versions of DTT. (Abstract shortened by UMI.).

abstract: Source: Masters Abstracts International, Volume: 41-02, page: 0547.

abstract: Adviser: Nola Etkin.