991 resultados para Inherent chirality


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Small investors' sentiment has been proposed by behaviouralists to explain the existence and behavior of discount on closed-end funds (CEFD). The empirical tests of this sentiment hypothesis so far provide equivocal results. Besides, most of out-of-sample tests outside U.S. are not robust in the sense that they fail to well control other firm characteristics and risk factors that may explain stock return and to provide a formal cross-sectional test of the link between CEFD and stock return. This thesis explores the role of CEFD in asset pricing and further validates CEFD as a sentiment proxy in Canadian context and augments the extant studies by examining the redemption feature inherent in Canadian closed-end funds and by enhancing the robustness of the empirical tests. Our empirical results document differential behaviors in discounts between redeemable funds and non-redeemable funds. However, we don't find supportive evidence of CEFD as a priced factor. Specifically, the stocks with different exposures to CEFD fail to provide significantly different average return. Nor does CEFD provide significant incremental explanatory power, after controlling other well-known firm characteristics and risk factors, in cross-sectional as well as time-series variation of stock return. This evidence, together with the findings from our direct test of CEFD as a sentiment index, suggests that CEFD, even the discount on traditional non-redeemable closed-end funds, is unlikely to be driven by elusive sentiment in Canada.

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Movement education and adapted physical activity are content areas not addressed in pre-service education or in-service training for Ontario practitioners working with individuals with disabilities in physical environments. Consequently, physical activity is often overlooked by service providers in programming and intervention for exceptional young learners. A formative evaluation, multiple-case study design was employed in this research in which a purposeful sample of expert practitioners performed a guided, descriptive evaluation of a three-day professional development workshop curriculum designed to supplement these areas lacking in professional preparation within their respective cohorts. Case-by-case and comparative analyses illustrated the inherent assumptions and societal constraints which prioritize the structure of professional development within the education system and other government organizations providing services for school-aged persons with disabilities in Ontario. Findings, discussed from a critical postmodern perspective, illustrate the paradoxical nature of Western values and prevailing mind/body dichotomy that guide professional practice in these fields.

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The purpose of this project was to discern the inherent tension present in narratives told by adolescents with a visual impairment as they attempted to make sense of their experiences, specifically those surrounding risk. Mediated action, based on the foundational work of Vygotsky and Bakhtin, was used as both a theoretical and methodological approach; it is the theory that there are two components that constitute any human action: the "agent," or the person who is doing the acting, and the "mediational means" that he or she is using to accomplish the action in question. Tension ensues as neither is able to fully explain human behaviour. Ten adolescents with a visual impairment participated in a narrative interview, revealing numerous counter-narratives surrounding risk-taking, including "experimentation undertaken using good judgment." Participants offered examples of how they engaged, appropriated, resisted and transformed the dominant narratives of disability and adolescence in their identity formation.

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This thesis explored the development of several methodologies for the stereoselective construction of ligand frameworks and some of their applications. The first segment concerns the application of an enantioselective lithiation at an Sp3_ hybridized position adjacent to nitrogen by means of the widely used and typically highly effective enantioselective lithiation with ( -)-sparteine. This investigation was intended to develop a method to install chirality into a system that would be converted into a family of diaminoylidenes for use as phosphine mimics in transition metal catalysis or as nucleophilic reagents. Molecular modeling of the system revealed some key interactions between the substrate and (-)-sparteine that provided general insight into the diamine's mode of action and should lend some predictive value to its future applications. The second portion focuses on the development of methods to access 1,2- disubstituted aminoferrocenes, an underexplored class of metallocenes possessing planar chirality. Two routes were examined involving a diastereoselective and an enantioselective pathway, where the latter method made use of the first BF3-mediated lithiation-substitution to install planar chirality. Key derivatives such as 1,2- aminophosphines, made readily accessible by the new route, were evaluated as ligands for Pd(II), Pt(II) and Ir(I). These complexes show activity in a number of transformations with both achiral and prochiral substrates. Optimization experiments were conducted to prepare enantiomerically enriched 2-substituted-I-aminoferrocenes by direct asymmetric lithiation of BF3-coordinated tertiary aminoferrocenes. A predictive computational model describing the transition state of this reaction was developed in collaboration with Professor Travis Dudding's group (Department of Chemistry, Brock University). The predicted stereochemistry of the process was confirmed by single-crystal X-ray analysis of a 2-phosphino-l-dimethylaminoferrocene derivative. Enantiomerically pure samples of the aminophosphine ligands derived from this new process have given promising preliminary results in the enantioselective hydrogenation of prochiral alkenes and warrant further stUdy in metal-mediated catalysis.

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This thesis explored Canadian high performance Athletes' perceptions of the fairness of the SDRCC sport-specific arbitral process. Leventhal’s (1980) model of procedural justice judgment was found to be an effective tool for exploring Athletes’ perceptions of the fairness of the process. Five of his six procedural justice antecedents: consistency, bias suppression, accuracy of information, representativeness, and ethicality influenced the Athletes’ perceptions of the fairness of the process. Emergent data also revealed that the Athletes’ perceptions of fairness were also influenced by three contextual factors and an additional antecedent of procedural justice. Efficiency of the process, inherent power imbalance between Athletes and NSOs, and the measurable effect of the process on personal and professional relationships differentiate sport-specific arbitration from most other processes of allocation. The data also indicated that the opportunity to voice one’s case was also an important determinant of the Athletes’ perceptions of the fairness of the process.

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Psychopathy is associated with well-known characteristics such as a lack of empathy and impulsive behaviour, but it has also been associated with impaired recognition of emotional facial expressions. The use of event-related potentials (ERPs) to examine this phenomenon could shed light on the specific time course and neural activation associated with emotion recognition processes as they relate to psychopathic traits. In the current study we examined the PI , N170, and vertex positive potential (VPP) ERP components and behavioural performance with respect to scores on the Self-Report Psychopathy (SRP-III) questionnaire. Thirty undergraduates completed two tasks, the first of which required the recognition and categorization of affective face stimuli under varying presentation conditions. Happy, angry or fearful faces were presented under with attention directed to the mouth, nose or eye region and varied stimulus exposure duration (30, 75, or 150 ms). We found that behavioural performance to be unrelated to psychopathic personality traits in all conditions, but there was a trend for the Nl70 to peak later in response to fearful and happy facial expressions for individuals high in psychopathic traits. However, the amplitude of the VPP was significantly negatively associated with psychopathic traits, but only in response to stimuli presented under a nose-level fixation. Finally, psychopathic traits were found to be associated with longer N170 latencies in response to stimuli presented under the 30 ms exposure duration. In the second task, participants were required to inhibit processing of irrelevant affective and scrambled face distractors while categorizing unrelated word stimuli as living or nonliving. Psychopathic traits were hypothesized to be positively associated with behavioural performance, as it was proposed that individuals high in psychopathic traits would be less likely to automatically attend to task-irrelevant affective distractors, facilitating word categorization. Thus, decreased interference would be reflected in smaller N170 components, indicating less neural activity associated with processing of distractor faces. We found that overall performance decreased in the presence of angry and fearful distractor faces as psychopathic traits increased. In addition, the amplitude of the N170 decreased and the latency increased in response to affective distractor faces for individuals with higher levels of psychopathic traits. Although we failed to find the predicted behavioural deficit in emotion recognition in Task 1 and facilitation effect in Task 2, the findings of increased N170 and VPP latencies in response to emotional faces are consistent wi th the proposition that abnormal emotion recognition processes may in fact be inherent to psychopathy as a continuous personality trait.

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Development of guanidine catalysts is explored through direct iminium chloride and amine coupling, alongside a 2-chloro-l,3-dimethyl-IH-imidazol-:-3-ium chloride (DMC) induced thiourea cyclization. Synthesized achiral catalyst N-(5Hdibenzo[ d,t][1,3]diazepin-6(7H)-ylidene)-3,5-bis(trifluoromethyl) aniline proved unsuccessful towards O-acyl migrations, however successfully catalyzed the vinylogous aldol reaction between dicbloro furanone and benzaldehyde. Incorporating chirality into the guanidine catalyst utilizing a (R)-phenylalaninol auxiliary, generating (R)-2-((5Hdibenzo[ d,t] [1,3 ]diazepin-6(7H)-ylidene ) amino )-3 -phenylpropan-l-ol, demonstrated enantioselectivity for a variety of adducts. Highest enantiomeric excess (ee) was afforded between dibromofuranone and p-chlorobenzaldehyde, affording the syn conformation in 96% ee and the anti in 54% ee, with an overall yield of30%. Attempts to increase asymmetric induction were focused on incorporation of axial chirality to the (R)phenylalaninol catalyst using binaphthyl diamine. Incorporation of (S)-binaphthyl exhibited destructive selectivity, whereas incorporation of (R)-binaphthyl demonstrated no effects on enantioselectivity. Current studies are being directed towards identifying the catalytic properties of asymmetric induction with further studies are being aimed towards increasing enantioselectivity by increasing backbone steric bulk.

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The natural abundance of the N-heterocycle containing compounds has pushed the synthetic community toward the invention of new synthetic methods that result in the structural diversity of N-heterocycles. Among this, is the efficient and highly selective diamine mediated asymmetric lithiation process. Amongst the diamine chiral ligands, (-)-sparterine, which is a naturally occurring alkaloid proved to be an efficient one. Many successful, good yielding and highly selective lithiation reactions have been accomplished with the mediation by this chiral diamine base. Although, there are some examples of experimental and theoretical mechanistic studies in the literature, there is a lack of detailed understanding as to how it exactly induces the chirality. In this thesis is described a systematic investigation of how (-)-sparteine influences the stereoselectivity in the course of asymmetric lithiation reaction. This led us to the establishment of the function of A-ring’s β-CH2 effect and D-ring effect. Consequently, the importance of the A-ring and D-ring portions of (-)-sparteine in the stereoselectivity is unraveled. Another part of this thesis deals with the asymmetric lithiation of BF3-activated N,N- dimethylaminoferrocene in the presence of (1R, 2R)-N1,N2-bis(3,3-dimethylbutyl)-N1,N2-dimethylcyclohexane-1,2-diamine ( a (R,R)-TMCDA surrogate) with i-PrLi. Computational findings were in full accord with the experimental observations. Subsequently, the theoretically provided insights into the mechanism of the reaction were exploited in computational design of a new ligand. Unfortunately, the outcome of this design was not experimentally robust and an updated approach towards a successful design was explained.

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The synthesis and studies of two classes of poly dentate ligands are presented as two projects. In project 1, four new carboxamide ligands have been synthesised via the condensation of 2,2',6,6'-tetrachloroformyl-4,4'-bipyridine or 2,6-dichloroformyl pyridine together with heterocyclic amines containing pyridine or pyrazole substituents. The coordination chemistry of these ligands has been investigated and studies have shown that with a Cu(II) salt, two carboxamide ligands LJ and L2 afford large clusters with stoichiometries [Cu8(L1)4Cl16].CHCl3.5H2O.7CH3OH (I) and [Cu9(L2)6Cl6].CH3OH.5H2O.(C2H5)3N (II) respectively. [molecular diagram availabel in pdf]. X-ray diffraction studies of cluster (I) reveal that it has approximate S4 symmetry and is comprised of four ligands and eight copper (II) centers. Here, coordination takes place via amide 0 atoms, and pyrazole nitrogens. This complex is the first reported example of an octanuclear copper cluster with a saddle-shaped structure. The second cluster comprises nine copper ions that are arranged in a cyclic array. Each ligand coordinates three copper centers and each copper ion shares two ligands to connect six ligands with nine copper ions. The amide nitrogens are completely deprotonated and both amide Nand 0 atoms coordinate the metal centres. The cluster has three-fold symmetry. There are six chloride ions, three of which are bridging two neighbouring Cu(II) centres. Magnetic studies of (I) and (II) reveal that both clusters display weak antiferromagnetic interactions between neighbouring Cu(II) centers at low temperature. In the second project, three complexes with stoichiometries [Fe[N302](SCN)2]2 (III), R,R-[Fe[N3O2](SCN)2 (IV) and R,R-]Fe[N3O2](CN)2] (V) were prepared and characterized, where [N302] is a pentadentate macrocycle. Complex (III) was prepared via the metal templated Schiff-base condensation of 2,2',6,6'-tetraacetyl-4,4'-bipyridine together with 3,6-dioxaoctane-I,8-diamine and comprises of a dimeric macro cycle where the two Fe(II) centres are in a pentagonal-bipyramidal environment with the [N302] ligands occupying the equatorial plane and two axial NCS ligands. Complexes (IV) and (V) were prepared via the condensation of 2,6-diacetylpyridine together with a chiral diamine in the presence of FeCh. The synthetic strategy for the preparation of the chiral diamine (4R,5R)-4,5-diphenyl-3,6-dioxa-I,8-octane-diamine was elucidated. The chirality of both macrocycles (IV) and (V) was probed by circular dichroism spectroscopy. The crystal structure of (IV) at 200 K contains two independent molecules in the unit cell, both of which contain a hepta-coordinated Fe(II) and axial NCS ligands. Variable temperature magnetic susceptibility and structural studies are consistent with a high spin Fe(II) complex and show no evidence of any spin crossover behaviour. In contrast, the bis cyanide derivative (V) crystallizes with two independent molecules in the unit cell, both of which have different coordination geometries consistent with different spin states for the two Fe(II) centres. At 250 K, the molecular structure of (V) shows the presence of both 7- and a 6-coordinate Fe(II) complexes in the crystal lattice. As the temperature is lowered, the molecules undergo a structural change and at 100 K the structural data is consistent with a 6- and 5-coordinate Fe(II) complex in the unit cell. Magnetic studies confirm that this complex undergoes a gradual, thermal, spin crossover transition in the solid state. Photomagnetic measurements indicate this is the first chiral Fe (II) sea complex to exhibit a LIESST.

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This qualitative case study explored how the structural power imbalance in high performance sport influenced the bargaining process and resulting commercial rights and obligations of a single Canadian national sport organization’s (NSO1) Athlete Agreement. Principles comprising the doctrine of unconscionability, specifically the identification of a power imbalance between contracting parties, and the exploration of how that power imbalance influenced the terms of the contract, provided a framework to analyze factors influencing the commercial contents of NSO1’s Athlete Agreement. The results of this analysis revealed that despite the overarching influence of the inherent structural power imbalance on all aspects of NSO1 and its membership, an athletes’ level of commercial appeal can reach such heights as to balance the bargaining positions of both parties and subsequently influence the commercial contents of the Athlete Agreement.

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This mixed methods research explores the role of reading engagement in 30 grade 1 students’ motivation to read mobile electronic storybooks (eBooks) and cognitive strategies used during eBook reading. Data collection comprised motivation and parent questionnaires, behavioural observation checklists, cognitive strategies rubric, and teacher interviews. Students’ emotional engagement with and enjoyment of mobile eBooks corresponded to 4 motivational aspects of intrinsic motivation: curiosity, control, choice, and challenge. Post-intervention results indicated that most student participants enjoyed answering eBook comprehension questions and preferred eBooks to print books; by the end of the study, all had access to a mobile device at home. A majority of participants were actively engaged during mobile eBook reading sessions and persisted in answering embedded eBook comprehension questions, which together reflected students’ behavioural engagement and time-on-task during mobile reading. Students’ off-task behaviours related to iPads’ accessibility features and inherent reader-friendliness. All participants successfully answered evaluative questions requiring them to activate prior knowledge, and experienced higher levels of difficulty with making personal connections. The study highlights the importance of making school-based literacy practices relevant to students’ outside worlds, and discusses implications for teacher educators, administrators, curriculum developers, and eBook and other digital developers concerning the need for greater collaboration in order to more closely align technology resources with national curriculum expectations.

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The article discusses improving welfare by reducing fear by studying: Animal Sensory Perception, Animal Behavior Patterns, Animal Habituation and Temperament, Effects of Previous Handling, Training Animals, Training Time and Temperament, Genetic Effects on Handling, Handling of escaped Animals, Facilities, Aggression in Grazing Animals, Inherent Danger of Large Animals, Cattle and Car Accidents.

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The potential of formative assessment (FA) for informing learning in classroom-based nursing courses is clearly established in the literature; however, research on FA in clinical courses remains scarce. This inquiry explored the lived experience of nursing students using transcendental phenomenology and described the phenomenon of being assessed in clinical courses. The research question guiding the study was: How is the phenomenon of assessment experienced by nursing students when FA is formally embedded in clinical courses? Inherent in this question were the following issues: (a) the meaning of clinical experiences for nursing students, (b) the meaning of being assessed through FA, and (c) what it is like to be assessed when FA is formally embedded within clinical experiences. The noematic themes that illuminated the whatness of the participants’ experience were (a) enabled cognitive activity, (b) useful feedback, (c) freedom to be, (d) enhanced focus, (e) stress moderator, and (f) respectful mentorship. The noetic themes associated with how the phenomenon was experienced were related to bodyhood, temporality, spatiality, and relationship to others. The results suggest a fundamental paradigm shift from traditional nursing education to a more pervasive integration of FA in clinical courses so that students have time to learn before being graded on their practice. Furthermore, this inquiry and the literature consulted provide evidence that using cognitive science theory to inform and reform clinical nursing education is a timely option to address the repeated calls from nursing leaders to modernize nursing education. This inquiry contributes to reduce our reliance on assumptions derived from research on FA in nursing classrooms and provides evidence based on the reality of using formative assessment in clinical courses. Recommendations for future research are presented.

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This thesis describes two different approaches for the preparation of polynuclear clusters with interesting structural, magnetic and optical properties. Firstly, exploiting p-tert-butylcalix[4]arene (TBC4) macrocycles together with selected Ln(III) ions for the assembly of emissive single molecule magnets, and secondly the preparation and coordination of a chiral mpmH ligand with selected 3d transition metal ions, working towards the discovery of chiral polynuclear clusters. In Project 1, the coordination chemistry of the TBC4 macrocycle together with Dy(III) and Tb(III) afforded two Ln6[TBC4]2 complexes that have been structurally, magnetically and optically characterized. X-ray diffraction studies reveal that both complexes contain an octahedral core of Ln6 ions capped by two fully deprotonated TBC4 macrocycles. Although the unit cells of the two complexes are very similar, the coordination geometries of their Ln(III) ions are subtly different. Variable temperature ac magnetic susceptibility studies reveal that both complexes display single molecule magnet (SMM) behaviour in zero dc field and the energy barriers and associated pre-exponential factors for each relaxation process have been determined. Low temperature solid state photoluminescence studies reveal that both complexes are emissive; however, the f-f transitions within the Dy6 complex were masked by broad emissions from the TBC4 ligand. In contrast, the Tb(III) complex displayed green emission with the spectrum comprising four sharp bands corresponding to 5D4 → 7FJ transitions (where J = 3, 4, 5 and 6), highlighting that energy transfer from the TBC4 macrocycle to the Tb(III) ion is more effective than to Dy. Examples of zero field Tb(III) SMMs are scarce in the chemical literature and the Tb6[TBC4]2 complex represents the first example of a Tb(III) dual property SMM assembled from a p-tert-butylcalix[4]arene macrocycle with two magnetically derived energy barriers, Ueff of 79 and 63 K. In Project 2, the coordination of both enantiomers of the chiral ligand, α-methyl-2-pyridinemethanol (mpmH) to Ni(II) and Co(II) afforded three polynuclear clusters that have been structurally and magnetically characterized. The first complex, a Ni4 cluster of stoichiometry [Ni4(O2CCMe3)4(mpm)4]·H2O crystallizes in a distorted cubane topology that is well known in Ni(II) cluster chemistry. The final two Co(II) complexes crystallize as a linear mixed valence trimer with stoichiometry [Co3(mpm)6]·(ClO4)2, and a Co4 mixed valence complex [Co(II)¬2Co(III)2(NO3)2(μ-mpm)4(ONO2)2], whose structural topology resembles that of a defective double cubane. All three complexes crystallize in chiral space groups and circular dichroism experiments further confirm that the chirality of the ligand has been transferred to the respective coordination complex. Magnetic susceptibility studies reveal that for all three complexes, there are competing ferro- and antiferromagnetic exchange interactions. The [Co(II)¬2Co(III)2(NO3)2(μ-mpm)4(ONO2)2] complex represents the first example of a chiral mixed valence Co4 cluster with a defective double cubane topology.

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The author outlines a new legal approach, which he labels federal constitutionalism, to the question of aboriginal difference in Canada. This approach has the potential to open up more fruitful avenues for the resolution of aboriginal law issues than either the “frozen rights” approach currently adopted by the Supreme Court of Canada or the treaty federalism approach, which posits that treaties should be used to resolve all differences between aboriginals and non-aboriginals. The author outlines the difficulties inherent in both the frozen rights and treaty federalism approaches. Federal constitutionalism, in contrast, draws its vitality from an organic understanding of Canada’s constitutional experience. It would allow aboriginal peoples to be seen as federal actors who have historically shaped the Canadian federation. Federal constitutionalism is a multi-faceted approach that would permit aboriginal questions to be addressed using the federal principle, thereby allowing the legal focus to move away from section 35 of the Constitution Act, 1982. Aboriginal peoples would be able to exercise the rights of sovereignty over their own internal affairs, while individual aboriginals could participate directly in federal and provincial governments without having to proceed through the intermediary of aboriginal representatives. Federal constitutionalism would allow aboriginal peoples a guaranteed sphere of autonomy, while permitting recognition of their historical interdependence with non-aboriginal peoples.