Cross validation (CV) is widely used for model assessment and comparison. In this thesis, we first review and compare three v-fold CV strategies: best single CV, repeated and averaged CV and double CV. The mean squared errors of the CV strategies in estimating the best predictive performance are illustrated by using simulated and real data examples. The results show that repeated and averaged CV is a good strategy and outperforms the other two CV strategies for finite samples in terms of the mean squared error in estimating prediction accuracy and the probability of choosing an optimal model. In practice, when we need to compare many models, conducting repeated and averaged CV strategy is not computational feasible. We develop an efficient sequential methodology for model comparison based on CV. It also takes into account the randomness in CV. The number of models is reduced via an adaptive, multiplicity-adjusted sequential algorithm, where poor performers are quickly eliminated. By exploiting matching of individual observations, it is sometimes even possible to establish the statistically significant inferiority of some models with just one execution of CV. This adaptive and computationally efficient methodology is demonstrated on a large cheminformatics data set from PubChem. Cross validated mean squared error (CVMSE) is widely used to estimate the prediction mean squared error (MSE) of statistical methods. For linear models, we show how CVMSE depends on the number of folds, v, used in cross validation, the number of observations, and the number of model parameters. We establish that the bias of CVMSE in estimating the true MSE decreases with v and increases with model complexity. In particular, the bias may be very substantial for models with many parameters relative to the number of observations, even if v is large. These results are used to correct CVMSE for its bias. We compare our proposed bias correction with that of Burman (1989), through simulated and real examples. We also illustrate that our method of correcting for the bias of CVMSE may change the results of model selection.

Carbon-carbon bond formation is one of the most important reactions in organic chemistry, and the Suzuki-Miyaura cross-coupling reaction has become a forerunner in this area. Considerable research has been directed at the mechanistic aspects and synthetic utility of the reaction; however, little attention has been given to the formation of the putative PdL2 catalysts. Due to their high reactivities, these catalysts are typically difficult to store and therefore are often generated in situ in unknown yields and at unknown rates via any number of available palladium precursors. This thesis describes research directed towards determining the optimum conditions to quantitatively generate compounds of the type Pd(0)Ln (L = PMePh2, PPh3, PCy3, PMeBut2, PBut3, dppe, dppp, dppf) from Pd(h5-C5H5)(h3-1-Ph-C3H4). Pd(h5-C5H5)(h3-1-Ph-C3H4) has been found to be a superior precursor for synthesizing catalytically active PdL2 compounds due to its ease in handling and reactivity with tertiary phosphines. Furthermore, investigations into the role of water in the transmetallation step of the Suzuki-Miyaura reaction are presented. The research indicates that water is necessary to effect the transmetallation step when coupling [NBu4][PhBF3] with 4-bromotoluene in toluene; however, the amount of water above one equivalent has no significant effect on the rate or yield of the reaction. / Thesis (Master, Chemistry) -- Queen's University, 2009-07-23 12:57:10.248

Until recently, secondary organoboronic esters were not viable substrates in the Suzuki-Miyaura cross-coupling reaction; however under recently reported conditions from the Crudden group1, which includes the addition of silver oxide to a palladium/phosphine catalyst system, this coupling can now be achieved. This thesis centres on optimizing the reaction conditions and expanding the substrate scope of this difficult but important secondary coupling. Optimal coupling conditions, for the example reaction of 4-iodoacetophenone and (R)-pinacol(1-phenylethyl)boronate, were found to be 8 mol% Pd(PPh3)4, 32 mol% PPh3, 1.5 eq. Ag2O and 1.5 eq. K2CO3 in DME at 85 °C for 24 h. This gave the desired coupling product in 64 % yield with 99.5 % retention of stereochemistry. Using this set of conditions, an array of aryl iodides were screened. The reaction conditions could not be extended to triflate or diazonium electrophiles. Amide functionality is important in many natural products and pharmaceuticals. The extension of reaction conditions to amides possessing boronic ester functionality at the β-position was attempted; however, no conditions could be determined to generate the cross-coupling product. An α-substitution pattern would better exemplify the benzylic positioning found to work for the original substrates. Attempts to synthesize the α-substituted amide were made without success. The optimal reaction conditions gave hope for differentiation between an aryl and a secondary aliphatic boronic ester. Using an aryl triflate to couple the aryl position and an aryl iodide to couple the aliphatic position, conditions for selective coupling were determined and applied to a one-pot procedure. / Thesis (Master, Chemistry) -- Queen's University, 2010-09-22 23:33:10.984

This study explores the experiences and perceptions of adult visitors to Canada who experience interaction problems. The researcher adapted Ilieva’s (2001) eight step culture exploration process to include the dimension of empathy which was used as a frame to help with analyzing the participants’ stories. The researcher expands the phenomenological lens by using a heuristic inquiry approach to highlight ten first-person accounts of adult English as an additional language (EAL) learners’ cross-cultural experiences in and out of classrooms. Using open-ended interviews as her primary data source, the researcher advocates for the use of empathy with EAL learners and her findings revealed main themes related to adult visitors’ acculturation such as acceptance of ambivalence, challenges with EAL, and cross-cultural learning. The information from the study provides a starting point to fill the gap in research involving the effectiveness of using empathy with EAL learners as a strategy for handling interaction problems.

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No description available.

This study explores the experiences and perceptions of adult visitors to Canada who experience interaction problems. The researcher adapted Ilieva’s (2001) eight step culture exploration process to include the dimension of empathy which was used as a frame to help with analyzing the participants’ stories. The researcher expands the phenomenological lens by using a heuristic inquiry approach to highlight ten first-person accounts of adult English as an additional language (EAL) learners’ cross-cultural experiences in and out of classrooms. Using open-ended interviews as her primary data source, the researcher advocates for the use of empathy with EAL learners and her findings revealed main themes related to adult visitors’ acculturation such as acceptance of ambivalence, challenges with EAL, and cross-cultural learning. The information from the study provides a starting point to fill the gap in research involving the effectiveness of using empathy with EAL learners as a strategy for handling interaction problems.

No description available.

No description available.

No description available.