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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.
361

The study of ruthenium(II) half-sandwich phosphido complexes containing pentamethylcyclopentadienyl (Cp*) ligand

Yang, Jin 20 December 2016 (has links)
Previous work in the Rosenberg group showed that the half-sandwich complexes Ru(η5-indenyl)Cl(PR2H)(PPh3) (2i), where R = cyclohexyl (Cy), isopropyl (Pri), phenyl (Ph), para-tolyl (Tolp), react with the strong, bulky base KOBut to give highly reactive complexes Ru(η5-indenyl)(PR2)(PPh3) (6i) containing a ruthenium-phosphorus double bond, Ru=PR2. The reactions of these phosphido complexes 6i with some reagents, such as alkenes, carbon monoxide and dihydrogen, illustrate their rich and varied reactivity. To better understand the mechanisms of these reactions (whether the indenyl effect is necessary), synthesis of analogous secondary phosphine complexes containing the pentamethylcyclopentadienyl (Cp*) ligand, Ru(η5-Cp*)Cl(PPh3)(PR2H) (2) were prepared via ligand substitution at Ru(η5-Cp*)Cl(PPh3)2 (1). Cp* phosphido complexes Ru(η5-Cp*)(PR2)(PPh3) (6) were generated in situ and their reactivity was investigated to see if they behaved similarly to the indenyl complexes. Experimental evidence in this thesis suggests that variable hapticity is not necessary in our indenyl system. In addition, these experimental evidence highlights enhanced lability of ligand at the bulky Cp*Ru fragment and higher Bronsted basicity of the phosphido ligand (PR2-) in Cp* phosphido 6 relative to the indenyl analogues 6i. / Graduate / 2017-12-11 / 0488 / yangjin@uvic.ca
362

Similarities and Differences in Borderline and Other Symptomology Among Women Survivors of Interpersonal Trauma with and Without Complex Ptsd

Marchesani, Estee Simpkins 12 1900 (has links)
Women interpersonal chronic trauma survivors are frequently misdiagnosed with borderline personality disorder (BPD) or post traumatic stress disorder (PTSD), which often results in mistreatment. Neither PTSD nor BPD adequately describes the unique character alterations observed among those exposed to prolonged early childhood trauma.  Researchers suggest survivors of interpersonal and chronic trauma should be subsumed under complex PTSD (CPTSD)(MacLean & Gallop, 2003).  The primary purpose of this study was to test the validity of complex PTSD as a construct. MANOVA, ANOVA, chi- Square, and independent samples t- Tests were utilized to test hypotheses. Results revealed that women who experienced higher frequencies of trauma met more CPTSD criteria and had higher mean base rate scores on the Major Depression, Depressive, Avoidant, Masochistic, Anxiety, PTSD, and Borderline scales of the MCMI- III than women who experienced fewer traumas. Additionally, findings suggest that the Major Depression, Depressive, Anxiety, PTSD, and Borderline scales may highlight differences among women interpersonal trauma survivors who meet five of six CPTSD criteria versus those who meet full CPTSD diagnostic criteria. Lastly, the mean Borderline scale score for women who met full CPTSD diagnostic criteria was below the cutoff for personality traits. Overall, these findings provide evidence and validation for the distinction of CPTSD from BPD and PTSD.
363

A Complex Network Approach to Analyzing the Structure and Dynamics of Power Grids

Cotilla-Sanchez, J. Eduardo 16 June 2010 (has links)
Electrical energy generation and distribution systems are good examples of complex systems. They include continuous, discrete, and social dynamics. They are operated by millions of human and non-human (or electro-mechanical) agents, and they show statistical properties found in other complex systems, such as power-law distributions in failure sizes. A number of recent large blackouts in Europe and North America have emphasized the societal importance of understanding these dynamics. Classical electromagnetic analysis alone frequently does not provide the insight required to characterize and mitigate risks in the electricity infrastructure. The objective of this thesis is to obtain insights into the dynamics of power grids using tools from the science of complex systems. In particular, this thesis will compare the topology, electrical structure, and attack/failure tolerance of power grids with those of theoretical graph structures such as regular, random, small-world, and scale-free networks. Simulation results in this thesis will describe the cost of the disturbances as a function of failure or attack sizes. The cost associated with network perturbations is often measured by changes on the diameter or average path length, whereas in the electricity industry, the loss of power demand (or blackout size) is the best indicator of the cost or impact of disturbances to electricity infrastructure.
364

Educating Youth in Foster Care: Educators’ Perspectives

Preston, Randall 15 June 2010 (has links)
This dissertation explores the education of foster care children through the perspectives of classroom teachers. Numerous studies have found that foster youth experience depressed educational outcomes relative to their peers. A meta-analysis of such studies reported depressed educational outcomes in terms of standardized test scores, grade averages, retention rates, and suspension and expulsion rates (Scherr, 2007). Foster care is most often associated with maltreatment, which in turn has been linked to depressed educational outcomes (Runyan, 1985) and to insecure attachment (Howe, 1999). Attachment theory, which emphasizes the impact of relationships in early childhood on future relationships, informed this study. Purposeful sampling was used to identify classroom teachers in a rural Vermont high school that serves a large number of foster youth relative to its size. Participants were selected based on their high degree of experience with and perceived success in supporting students in foster care. In interviews, teachers were asked to describe distinguishing characteristics of foster youth as well as their relationships with peers and adults while at school. Teachers described several characteristics of foster youth, including the perceived impact of trauma on foster youth‟s ability to attend to school and school related tasks. Teachers also characterized intense relationships between foster youth and their peers, and between foster youth and adults at school. Participants also identified several strategies they believed to be effective in supporting this population, each of which emphasized the development of caring relationships between teachers and foster youth. Teachers shared concerns about the impact of frequent placement changes on the educational experiences of foster youth. Interviewees also noted that their support of foster youth was hampered by insufficient information about changes in students‟ status. Intersections between the characteristics of foster youth and selected literature on attachment theory and traumatic stress are explored in the interpretation of the findings. Finally, this study utilizes a feminist ethic of care to contextualize relationships between foster youth in schools and effective teacher strategies.
365

Assessment of Feigning with the Trauma Symptom Inventory: Development and Validation of new Validity Scales with Severely Traumatized Patients

Payne, Joshua W. 05 1900 (has links)
Currently, only the TSI assesses complex traumatic reactions and patient response styles. However, its feigning scale, ATR, uses a flawed detection strategy and is potentially confounded by experiences of complex PTSD. As a consequence, clinicians using the TSI to evaluate severely traumatized patients have no useful method for discriminating genuine and feigned responding. Several detection strategies have demonstrated utility within evaluations of feigned trauma including the assessment of rare symptoms, symptom combinations, symptom selectivity, and symptom severity. The current study created scales on the TSI according to these strategies using a development sample of 107 severely traumatized patients. Validation of all TSI feigning scales was then performed with a second independent sample of 71 severely traumatized patients using a mixed simulation design. Results found support for each scale's convergent validity with SIRS primary scales (M rs = .52) and discriminant validity with measures of defensiveness on the SIRS (M rs = -.07) and TSI (M rs = -.19). Each scale also produced expectedly mild to moderate relationships with SADS-C clinical scales (M rs = .32) and the SCID-IV PTSD module (M rs = -.02). Support for their criterion validity was only moderate (M ds = .69) when comparing the scores of genuine patients to those simulating disability. Potential explanations for this trend were reviewed, including (a) the impact of comorbidity, (b) the restrictions associated with creating embedded feigning scales, and (c) the influence of simulator knowledge in analogue designs. Limitations of the study and future avenues of research were discussed.
366

Supersymmetry and geometry of hyperbolic monopoles

Gharamti, Moustafa January 2015 (has links)
This thesis studies the geometry of hyperbolic monopoles using supersymmetry in four and six dimensions. On the one hand, we show that starting with a four dimensional supersymmetric Yang-Mills theory provides the necessary information to study the geometry of the complex moduli space of hyperbolic monopoles. On the other hand, we require to start with a six dimensional supersymmetric Yang-Mills theory to study the geometry of the real moduli space of hyperbolic monopoles. In chapter two, we construct an off-shell supersymmetric Yang-Mills-Higgs theory with complex fields on three-dimensional hyperbolic space starting from an on-shell supersymmetric Yang-Mills theory on four-dimensional Euclidean space. We, then, show that hyperbolic monopoles coincide precisely with the configurations that preserve one half of the supersymmetry. In chapter three, we explore the geometry of the moduli space of hyperbolic monopoles using the low energy linearization of the field equations. We find that the complexified tangent bundle to the hyperbolic moduli space has a 2-sphere worth of integrable structures that act complex linearly and behave like unit imaginary quaternions. Moreover, we show that these complex structures are parallel with respect to the Obata connection, which implies that the geometry of the complexified moduli space of hyperbolic monopoles is hypercomplex. We also show, as a requirement of analysing the geometry, that there is a one-to-one correspondence between the number of solutions of the linearized Bogomol’nyi equation on hyperbolic space and the number of solutions of the Dirac equation in the presence of hyperbolic monopole. In chapter four and five, we shift the focus to supersymmetric Yang-Mills theories in six dimensional Minkowskian spacetime. Via dimensional reduction we construct a supersymmetric Yang-Mills Higgs theory on R3 with real fields which we then promote to H3. Under certain supersymmetric constraints, we show that hyperbolic monopoles configurations of this theory preserve, again, one half of the supersymmetry. Then, through investigating the geometry of the moduli space we showthat the moduli space is described by real coordinate functions (zero modes), and we construct two sets of 2-sphere of real complex structures that act linearly on the tangent bundle of the moduli space, but don’t behave like unit quaternions. This result coincides with the result of Bielawski and Schwachhöfer, who called this new type of geometry pluricomplex geometry. Finally, we show that in the limiting case, when the radius of curvature H3 is set to infinity, the geometry becomes hyperkähler which is the geometry of the moduli space of Euclidian monopoles.
367

Localization and activation of the fission yeast γ-tubulin complex by Mto1/2

Lynch, Eric Michael January 2013 (has links)
Microtubules (MTs) are important components of the eukaryotic cytoskeleton, with critical functions in intracellular trafficking, establishing and maintaining cell morphology, and segregating chromosomes during mitosis. MTs are hollow, cylindrical polymers composed of αβ-tubulin heterodimers. The longitudinal assembly of αβ-tubulin subunits generates protofilaments, and multiple protofilaments (typically 13 in vivo) interact laterally to form the wall of the MT. In vitro, the polymerization of MTs proceeds in two steps: nucleation and elongation. During the nucleation phase, several αβ-tubulin subunits associate to form a seed, from which further MT elongation then occurs. However, at the relatively low αβ-tubulin concentrations found in vivo, the spontaneous assembly of MTs is not favoured, due largely to the slow kinetics of MT nucleation. The nucleation of MTs in vivo requires the γ-tubulin complex (γ-TuC), a ring-like complex composed of γ-tubulin and γ-tubulin complex proteins (GCPs). Two copies of γ- tubulin associate with one copy each of GCP2 and GCP3 to produce the γ-tubulin small complex (γ-TuSC). Multiple γ-TuSCs, along with the additional GCPs 4,5, and 6, assemble to form the larger γ-tubulin ring complex (γ-TuRC). The γ-TuRC contains a ring of 13 γ-tubulins, which acts as a template for the nucleation of MTs. Typically, the γ-TuC nucleates MTs only when localized to specific subcellular sites, referred to as microtubule organizing centres (MTOCs). However, the precise mechanism by which the γ-TuC is activated at MTOCs remains unknown. In fission yeast, the proteins Mto1 and Mto2 form a complex (Mto1/2) required for the nucleation and organization of cytoplasmic MTs. Mto1/2 determines sites of MT nucleation by recruiting the γ-TuC to several different MTOCs. Different sequences in the Mto1 C-terminus independently confer γ-TuC localization to spindle pole bodies, MTs, and the cell equator. Here, I show that the Mto1 N-terminus is necessary for localization to the nuclear envelope (NE). By simultaneously removing the N- and C-terminal localization domains, I generated the "Mto1-bonsai" mutant, which fails to localize to any conventional MTOCs. In mto1-bonsai cells, MTs are still nucleated in the cytoplasm in an Mto1- dependent manner, but nucleation is spatially random. This reveals that targeting of the γ- TuC to conventional MTOCs is not necessary for MT nucleation, and suggests that Mto1/2 has a direct role in activating MT nucleation by the γ-TuC. Live-cell confocal microscopy allows us to detect individual MT nucleation events, in which newly nucleated MTs are associated with single γ-TuCs as well as Mto1/2-bonsai complexes. Fluorescence quantification reveals that these nucleating complexes contain approximately 13 molecules of both Mto1-bonsai and Mto2, matching the 13 copies of γ-tubulin anticipated for a single γ-TuC. We propose that Mto1/2 may contribute to γ-TuC activation by promoting γ-TuSC assembly and/or inducing conformational changes in the γ-TuC upon binding. I also expressed and purified recombinant Mto1/2-bonsai complex, using a baculovirus/insect cell system. This recombinant Mto1/2-bonsai self-assembles into higher-order complexes, comparable in size to the complexes analyzed in vivo by fluorescence microscopy.
368

Common metrics for cellular automata models of complex systems

Johnson, William January 2015 (has links)
The creation and use of models is critical not only to the scientific process, but also to life in general. Selected features of a system are abstracted into a model that can then be used to gain knowledge of the workings of the observed system and even anticipate its future behaviour. A key feature of the modelling process is the identification of commonality. This allows previous experience of one model to be used in a new or unfamiliar situation. This recognition of commonality between models allows standards to be formed, especially in areas such as measurement. How everyday physical objects are measured is built on an ingrained acceptance of their underlying commonality. Complex systems, often with their layers of interwoven interactions, are harder to model and, therefore, to measure and predict. Indeed, the inability to compute and model a complex system, except at a localised and temporal level, can be seen as one of its defining attributes. The establishing of commonality between complex systems provides the opportunity to find common metrics. This work looks at two dimensional cellular automata, which are widely used as a simple modelling tool for a variety of systems. This has led to a very diverse range of systems using a common modelling environment based on a lattice of cells. This provides a possible common link between systems using cellular automata that could be exploited to find a common metric that provided information on a diverse range of systems. An enhancement of a categorisation of cellular automata model types used for biological studies is proposed and expanded to include other disciplines. The thesis outlines a new metric, the C-Value, created by the author. This metric, based on the connectedness of the active elements on the cellular automata grid, is then tested with three models built to represent three of the four categories of cellular automata model types. The results show that the new C-Value provides a good indicator of the gathering of active cells on a grid into a single, compact cluster and of indicating, when correlated with the mean density of active cells on the lattice, that their distribution is random. This provides a range to define the disordered and ordered state of a grid. The use of the C-Value in a localised context shows potential for identifying patterns of clusters on the grid.
369

MHC, parasite burden and heterozygosity in the blue shark (Prionace glauca, L.1758)

McMillan, Heather Anne January 2013 (has links)
The blue shark (Prionace glauca) is a highly migratory pelagic elasmobranch that inhabits ocean basins globally. As a result, this shark is exposed to intensive ocean exploitation by commercial target fisheries, by-catch and for recreational pursuits globally. This top predator is therefore at high risk of becoming overfished. Advances to current knowledge of genetic population structure and diversity of this species would provide vital information required to initiate co-operative management approaches. In this study, the major histocompatibility complex (MHC) class IIa and IIβ genes were successfully isolated and characterised from blue sharks. Phylogenetic trees of the class II genes showed three major clades; one of teleost fish, one of tetrapods and one of sharks. The MHC class IIβ gene exon 2 primers successfully amplified partial sequences in blue sharks from several global locations. Analysis of sequences using denaturing gradient gel electrophoresis (DGGE) suggested the assay resolved different sequences up to one basepair, making the assay potentially very useful with further development. The class II genes presented in this study show conflicting evidence for the presence of more than one class II locus. To explore inheritance patterns of MHC exon 2 diversity, a single blue shark litter (mother + 19 pups) was cloned and sequenced, revealing evidence to suggest the possibility of more than one locus for class IIβ. Statistical analysis of parasite loads and diversities from blue shark spiral valves revealed no definitive population structure, supporting global and North Atlantic mtDNA and microsatellites genetic analyses presented here. The size (fork length) of sharks was found to be potentially influential when modelled with individual microsatellite heterozygosity and fork length. International co-operation will be required to prevent this species becoming extinct from global marine ecosystems. Reductions in numbers could lead to reduced genetic diversity, decreased immunity and ultimately an 'unhealthy' population.
370

Reaksies van tione met en in metaalkomplekse

01 September 2015 (has links)
D.Sc. / Please refer to full text to view abstract

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