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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

A molecular approach to study the monoterpene-induced response in Arabidopsis thaliana

Godard, Kimberley-Ann 05 1900 (has links)
A wound- and insect-inducible expression system for transgenic plants was developed. Specifically, I demonstrate wound- and insect-inducible, localized gene expression driven by the potato proteinase inhibitor II (pinII)-promoter in transformed Arabidopsis, tobacco and white spruce. As reporter and target genes driven by the pinII-promoter, I used the GUS gene and a terpenoid synthase gene, respectively. In addition, I found that the pinII-promoter drives trichome-specific, systemically-induced gene expression in tobacco and Arabidopsis. Finally, I demonstrate that the pinII–promoter, when transformed into Arabidopsis, is extremely sensitive to subtle, low-impact stress treatment. This latter finding prompted me to use, in the second part of my thesis, the pinII-promoter in conjunction with GUS reporter gene expression to test if intact Arabidopsis plants can respond to exposure to monoterpene volatiles. My experiments using the pinII–promoter GUS reporter system clearly established that Arabidopsis plants respond to the exposure of the monoterpene volatiles tested. It is thought that monoterpenes and other volatiles can act as airborne signals between plants under stress or between distant parts of the same plant. At the outset of my thesis research, and to some extent still today, the concept of plant-plant signalling with volatiles has been met with scepticism. After establishing that Arabidopsis plants do respond in a laboratory setting to certain monoterpene volatiles, I further tested the extent of the response at the transcriptome level using a 30 K microarray platform. The gene expression analysis revealed several hundred transcripts that respond with a change of abundance in response to treatment of intact Arabidopsis plants with the monoterpenes ocimene or myrcene. Many of these transcripts were annotated as stress and defense genes including genes involved in octadecanoid signaling. Real-time PCR analyses of octadecanoid mutants confirmed a role for octadecanoid signaling in the response to the monoterpene ocimene. In addition, treatment with ocimene or myrcene caused increased levels of methyl jasmonate (MeJA) in Arabidopsis rosette leaves. However, plants treated with monoterpene prior to wounding or feeding by cabbage looper did not reveal any significant priming effect for these pre-treatments.
82

Clinical and endocrine responses to ovarian hyperstimulation in flare and and luteal gonadotropin-releasing hormone agonist (GnRHa) protocols

Nguyen, Tuan-Anh T 11 1900 (has links)
Background: Due to the “flare effect” associated with the flare protocol, variation in the degree of follicular maturation during stimulation may result in differences in follicle response as compared to the luteal protocol which is based on maximal pituitary suppression and synchronization of follicular maturation. In this study, besides other methods, Anti-Mullerian Hormone (AMH), a novel marker for ovarian reserve, was used as a tool to evaluate the ovarian responsiveness to stimulation. Methods: Women undergoing IVF/ICSI treatment in the UBC IVF Program from January to December 2006 using luteal and flare protocols were retrospectively selected for a total of 40 treatment cycles, 20 cycles in each protocol matched by age, weight, and indication for IVF/ICSI. Serial serum Estradiol (E₂) levels and follicle data were obtained from the clinic chart. Follicle stimulating hormone (FSH), Luteinizing Hormone (LH), progesterone (P), androstenedione (D₄) and AMH levels were measured from aliquots of frozen serum samples. Hormone responses were evaluated by Area Under the Curve (AUC). Data were analyzed using the t-test and statistical significance was considered present at P<0.05. Results are reported as the mean ± SEM. Results: For flare versus luteal protocol, there was a significant difference in the number of total follicles (14.5 ± 1.8 vs 21.3 ± 2.3), medium follicles (3.7 ± 0.6 vs 8.4 ± 1.3), eggs retrieved (8 ± 0.8 vs 14 ± 1.4) and oocytes fertilized (4.4 ± 0.5 vs 8.4 ± 0.7), AMH AUC (62 ± 12 vs 111 ± 13), LH AUC (67 ± 21 vs 20 ± 9), FSH AUC (171 ± 59 vs 112 ± 29), respectively. Mean number of embryos transferred in both groups was similar. Number of pregnancies conceived (5 for flare and 10 for luteal protocol) was not significantly different. Although E₂ AUC in luteal protocol was higher than that in flare protocol, the difference was not statistically significant (28,339 ± 2,669 vs 26,905 ± 2,790). Differences in P and D₄ AUC between the two protocols were not statistically significant. Correlations with ovarian follicles and eggs retrieved were better for AMH than E₂. Conclusions: The luteal protocol exhibited a better ovarian response to stimulation as compared to the flare protocol. As compared to E₂, AMH had a better correlation with the number of follicles and eggs retrieved.
83

Aqueous protein based extraction of oat beta glucan and its physiological effects on satiety and glycaemic responses in healthy adults

Katongole, Joseph 03 January 2012 (has links)
β-D-Glucan has been proposed to suppress appetite related perceptions thus contribute favourably to the regulation of energy intake and the increasing obesity problem in North America. Due to its low concentrations in grains, the challenge has been to produce β-glucan concentrates that can be incorporated into foods without adversely affecting product attributes. Therefore in the first part of the study, a protocol for the concentration of β-glucan, based on protein-polysaccharide incompatibility, was investigated. The extract obtained was utilized in the second part, where the effect of beverages with increased β-glucan content on perceived satiety and blood glucose, at different fibre concentrations was studied. Twenty nine healthy adults participated in this study. 5 beverage pre-loads, containing between 0-2.5 g of β-glucan in 500 mL of the sample, were ingested 120 min before the given meal. Results showed a trend towards a decrease in appetite scores with increasing β-glucan content of the beverages, as well as differences in the blood glucose readings, though these were not significant, and could not solely be attributed to β-glucan content due to differences in beverage composition.
84

What Makes Art Good?A Case Study of Children’s Aesthetic Responses to Art Works

Greenwood, Toby January 2011 (has links)
This study explores what 10-12-year-old students say they like and value in works of visual art. As the participants talk about their own and other people‟s art works they are formulating and expressing aesthetic responses and beginning to shape their individual aesthetic awareness. Because of the age of the participants, the exploration is framed in terms of “what makes art good”. The research was prompted by the introduction and implementation of the New Zealand Curriculum (2007), which not only positions art as a core area of learning, but also outlines values and key competencies that characterise a constructivist approach to knowledge. Such an approach requires active engagement by learners and suggests that it is important for teachers to understand their students‟ values and views. However, in the field of art education there is little published material that examines the views and reactions of students. A broadly qualitative approach to the case study was taken, drawing particularly on phenomenography and narrative. The study found that 10-12 year-old students do actively make judgements about art works, and while there are common themes that occur repeatedly, the bases of such judgement vary from student to student. The study also found students‟ ways of approaching art-making varied, with some, for example, concerned predominantly with the technical process while others were more interested in imagery or narrative intention. The thesis argues that it is important for teachers to be aware of how their students individually process their aesthetic responses in order to develop relevant and appropriate programmes.
85

Mödrars upplevelse av stress relaterat till föräldraskapet

Nasenius, Annelie January 2014 (has links)
No description available.
86

EXPERIMENTAL RESPONSE OF A PILE IN SAND UNDER STATIC AND CYCLIC LATERAL LOADS

Oghabi, PEGAH 05 May 2014 (has links)
Piles are engineering structures which are subjected to axial and lateral loading. In this dissertation, pile load tests were performed on a full-scale fabricated pile to understand lateral pile responses under static and cyclic loading. The experiments were performed on a fabricated test pile at the Geo-Engineering Laboratory at Queen's University. Dry loose Olimag Synthetic Olivine sand was used as the test soil. Instrumentation including axial strain gauges, null sensors (earth pressure sensors) and string potentiometers were used to monitor pile responses throughout the tests. What differentiates the current study from previous investigations is direct measurements of lateral earth pressure on a test pile using those null sensors with conventional measurements of curvature and deformation. The null sensors of Talesnick (2005) have ‘infinite stiffness’ and calibration that is almost independent of the soil type, soil condition and stress history, qualities that make the sensor superior to other commercially available sensors. The initial pile response under static loading was examined. Previous laterally loaded pile test programs have utilized curvature measurements to infer moments, and differentiation of moments to determine lateral forces. Comparisons with the directly measured pressures confirmed the effectiveness of differentiated moments. To understand offshore structures, the behaviour of a pile subjected to cyclic loading is examined and explained by elastic soil response at low load levels and the progressive development of inelastic response at higher load levels. In addition, the loading condition (i.e. two-way versus one-way loading) was found to have a substantial effect on pile responses. The pressure distributions for two-way cyclic loading suggest that the lateral pressure is proportional to displacement with peak pressures near the ground surface during elastic responses. The peak lateral pressures move deeper towards the point of rotation with increasing cyclic loads to generate inelastic responses. However, the lateral pressure response is consistently inelastic for one-way loading. / Thesis (Master, Civil Engineering) -- Queen's University, 2014-05-02 20:29:56.489
87

Resisting Bullying: Narratives of Victims and Their Families

Khanna, Savitri 26 April 2013 (has links)
Bullying has severe consequences for school-aged adolescents who have experienced repeated victimization and for the families as well. While there is a considerable body of research on bullying and its effects on victims, very little research has been devoted to studying the experiences and resistance of the targeted young people and their families in the bullying situations. The literature on bullying characterizes victims as unable to defend themselves; this depiction is limited, simplistic, and one-dimensional. This dissertation presents an alternate view, focusing on the experiences and responses of victims and their families. The thesis draws on a poststructural view and a response-based framework to present a new perspective on the victims of bullying—a perspective that contrasts with the common depiction of “helpless, powerless victims” and foregrounds the personal agency of young people who have responded to bullying. Data for this study was collected in the form of narratives from the families and eleven to fifteen year old school adolescents who have been targets of ongoing bullying. The sample consisted of four families and five adolescents. The interview questions were based on Allan Wade’s response-based approach. The participants’ narratives focused on their responses to bullying. Each narrative was read thoroughly for themes related to the skills and the knowledge adolescents have used in responding to peer aggression. Similarly, parents’ narratives were examined for themes of their responses to the bullying of their children. The conclusion from the findings indicated that the parents and adolescents responded to bullying in many small but prudent and resourceful ways.
88

Responses to supplementary UV radiation of some temperate meadow species

Cooley, Nicola M. January 2001 (has links)
The growth and development of various meadow species was monitored while growing under enhanced UV-radiation in the natural light environment. Growth responses to supplementary ultraviolet-B (UV-B+A) were mostly inhibitory when compared to the ambient daylight treatment for Bellis perennis, Cardamine pratensis, Cynosurus critatus and Ranunculus ficaria. When the response of ultraviolet-A (UVA) treated plants were compared with those of the UV-B+A, differences were found which varied according to the species and parameter investigated. No correlation in B. perennis growth responses could be made with reallocation of carbohydrates or with photosynthesis. The stomata of B. perennis grown under enhanced UV-B+A were less capable of closing than those of the ambient plants. Increases in the concentration of UV-absorbing compounds were found in the UV radiation treatment when dry weight accumulation was inhibited in C. pratensis. To further understand the growth responses of the UV-A treatment and their relationship to the UV-B responses, polychromatic action spectra in the natural environment were employed. B. perennis had an action maximum in the UV-B (280-315 nm), while C. cristatus demonstrates no action in the UV-B but action in the UV-A region (315-400 nm). Dry weight accumulation was found to respond differently to UV treatments when investigating Arabidopsis thaliana ecotypes. UV-B+A treatment was found to inhibit dry weight accumulation in most ecotypes. When UV-B+A induced inhibition was expressed in terms of ambient growth rate for each ecotype, a linear relationship could be derived. The higher the growth rate the more susceptible the ecotype was to UV-B+A inhibition. The pertinence of the UV-A treatment and UV protocol is discussed. It is suggested that UV responses could alter the diversity of the meadow equilibrium and these effects could be exacerbated by water loss.
89

Vibration serviceability of long-span cast in-situ concrete floors

Pavic, Aleksandar January 1999 (has links)
This thesis describes an investigation into the vibration serviceability of long-span and slender in-situ concrete floors, which are typically post-tensioned. The motivation for the research is the present trend towards increased slenderness of post-tensioned floors supporting open-plan high- quality offices where vibration serviceability may easily become the governing design criterion. The vibration serviceability issue in post-tensioned floors is now also recognised by the UK Concrete Society which proposed, for the first time, guidelines for performing a vibration serviceability check when designing office floors. The guidelines were published in Concrete Society Technical Report 43 (CSTR43) in 1994 and its publication prompted the initialisation of this research project. There were two reasons for this. Firstly, problems were reported with the reliability and practical application of these guidelines, and, secondly, the guidelines were not experimentally verified which is unusual for any design provision related to vibration serviceability. In order to improve understanding of the dynamic performance of a rather specific group of office floors which are long-span and made of cast in-situ concrete, a combined experimental and analytical approach has been adopted. A state-of-the-art facility comprising hardware and software suitable for field modal testing and dynamic response measurements of prototype floor structures was commissioned as a part of this research. The facility is built up around the instrumented sledge hammer, which served as the main excitation source in modal testing, and multi-degree-of-freedom vibration parameter estimation procedures utilising measured floor frequency response functions. The main testing programme consisted of modal testing of four prototype floor structures of varying complexity weighing between 13 and 1000 tonnes. All four slab structures were slender and made of in-situ concrete. These tests were complemented by measurements of the floors' acceleration responses to a single person walking excitation tuned to create as large as realistically possible responses. The modal testing experimental data (measured natural frequencies, mode shapes and modal damping ratios) were used to validate numerical finite element (FE) models representing each floor structure. To do this, advanced FE model correlation and manual updating procedures were employed. Results of these exercises highlighted a number of important issues related to the dynamic behaviour of the concrete floors investigated. Firstly, the bending stiffness of in-situ concrete columns and walls contributed significantly to overall floor bending stiffness and must be considered. Secondly, higher modes of vibration which are close to the fundamental frequency appear in concrete floors, and should not be neglected as they can be easily excited by walking leading to dynamic responses greater than those associated with the fundamental mode. Thirdly, the width of band beams contributes significantly to the lateral stiffness of post-tensioned floors, which, in turn, may be very beneficial for their vibration serviceability. The validated numerical FE models were then used to check the performance of three representative walking excitation models available in the literature. It was shown that, in general, all three models overestimated the measured response to the third harmonic of the walking excitation, which is particularly important for low-frequency office floors. Only one of the models did so in a way which is not overly conservative. This model is recommended for use in vibration serviceability assessment of post-tensioned floors. Finally, gross oversimplification of these important issues is identified as the principal reason for the failure of the current CSTR43 vibration serviceability guidelines to predict reliably vibration response of a wide range of post-tensioned in-situ cast concrete floors.
90

Association of Intersex in Wild Fish with Wastewater Effluent in the Grand River, Ontario

Tanna, Rajiv Neal January 2012 (has links)
The Grand River watershed is the largest watershed in southern Ontario, and is expected to see major development and urban densification over the next 20 years. An expected 57% increase in population over the next two decades in urban centers such as Kitchener – Waterloo, Cambridge, Guelph and Brantford means an added load on the existing 30 wastewater treatment facilities serving the watershed. A subsequent increase in the amount of average flow and effluent released into the Grand River via the Waterloo and Kitchener wastewater treatment plants is also expected. The Waterloo and Kitchener wastewater plants are both secondary treatment plants, although neither plant currently nitrifies the wastewater prior to release. As a result, increased concentrations of ammonia and nitrate are found downstream of the treatment plant outfalls. Compounds introduced into the Grand River via the discharge of wastewater effluent can have impacts on resident biota such as fish. Disruption of the normal function of endocrine systems in fish has been associated with municipal effluents as well as chemicals that have been detected in these effluents. One of the major responses has been the presence of intersex (oocytes in testes) in fish downstream of the wastewater plant outfalls at sites around the globe. The research in this thesis examined resident fish for the variability and extent of intersex condition by adapting a new fragmented testis technique. Biomarkers of response such as relative gonad weight (GSI), relative liver weight (LSI) and condition (K) were also measured. The study focused on the Rainbow Darter (Etheostoma caeruleum) a dominant benthivorous fish species in the riffle habitats in the Grand River. An increased proportion of male Rainbow Darters sampled immediately downstream of the Waterloo outfall had a gonad lobe containing at least one testis-oocyte. The number of Rainbow Darter with more severe intersex (10-99 oocytes/lobe) also increased immediately downstream of the Waterloo outfall. A much more dramatic expression of intersex proportion and severity (>100 oocytes per testis lobe) was observed further downstream, below the Kitchener outfall. These patterns in intersex presence and severity were also observed in two other species collected at a subset of the original sites. Although there were minimal changes in GSI, LSI and K below the Waterloo outfall, differences were observed downstream of the Kitchener wastewater effluent outfall. Female Rainbow Darter downstream of the Kitchener outfall showed significant decreases in GSI and LSI, and increases in K. Male Rainbow Darter GSI and LSI data across sites did not express changes that coincided with MWWE outfalls, although small increases in condition were observed. These patterns of intersex and organism level responses suggest that the assimilation of wastewater effluent into natural receiving environments may have impacts on endocrine function and energy use and allocation in wild fish.

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