Phonon spectra and thermodynamic properties of rare gas solids based on empirical and semi-empirical (ab initio) two-body potentials : a comparative study /

We study the phonon dispersion, cohesive and thermal properties of raxe gas solids Ne, Ar, Kr, and Xe, using a variety of potentials obtained from different approaches; such as, fitting to crystal properties, purely ab initio calculations for molecules and dimers or ab initio calculations for solid crystalline phase, a combination of ab initio calculations and fitting to either gas phase data or sohd state properties. We explore whether potentials derived with a certain approaxih have any obvious benefit over the others in reproducing the solid state properties. In particular, we study phonon dispersion, isothermal ajid adiabatic bulk moduli, thermal expansion, and elastic (shear) constants as a function of temperatiue. Anharmonic effects on thermal expansion, specific heat, and bulk moduli have been studied using A^ perturbation theory in the high temperature limit using the neaxest-neighbor central force (nncf) model as developed by Shukla and MacDonald [4]. In our study, we find that potentials based on fitting to the crystal properties have some advantage, particularly for Kr and Xe, in terms of reproducing the thermodynamic properties over an extended range of temperatiures, but agreement with the phonon frequencies with the measured values is not guaranteed. For the lighter element Ne, the LJ potential which is based on fitting to the gas phase data produces best results for the thermodynamic properties; however, the Eggenberger potential for Ne, where the potential is based on combining ab initio quantum chemical calculations and molecular dynamics simulations, produces results that have better agreement with the measured dispersion, and elastic (shear) values. For At, the Morse-type potential, which is based on M0ller-Plesset perturbation theory to fourth order (MP4) ab initio calculations, yields the best results for the thermodynamic properties, elastic (shear) constants, and the phonon dispersion curves.

Implementing a question-generation strategy with bilingual students: exploring the perspectives of a beginning teacher /

This study examined the challenges associated with the explicit delivery of questiongeneration strategy with 8 Arab Canadian students from the perspective of a bilingual beginning teacher. This study took place in a private school and involved 2 stages consisting of 9 instructional sessions, and individual interviews with the students. Data gathered from these interviews and the researcher's field notes from the sessions were used to gain insights about the participants' understanding and use of explicit instruction. The themes that emerged from the data included "teacher attitude," "students' enhanced metacognitive awareness and strategy use," "listening skills," and "instructional challenges." Briefly, teacher's attitude demonstrated how teacher's beliefs and knowledge influenced her willingness and perseverance to teach explicitly. Students' enhanced metacognitive awareness and strategy use included students' understanding and use of the question-generation strategy. The students' listening skills suggested that culture may influence their response to the delivery of explicit instruction. Here, the cultural expectations associated with being a good listener reinforced students' willingness to engage in this strategy. Students' prior knowledge also influenced their interaction with the question-generation strategy. Time for process versus covering content was a dominant instructional challenge. This study provides first hand information for teachers when considering how students' cultural backgrounds may affect their reactions to explicit strategy instruction.

Perturbing the impulse activity of a single identified neuron augments the formation of long-term memory in a molluscan semi-intact preparation /

The aim of this study was to investigate the neural correlates of operant conditioning in a semi-intact preparation of the pond snail, Lymnaea stagnalis. Lymnaea learns, via operant conditioning, to reduce its aerial respiratory behaviour in response to an aversive tactile stimulus to its open pneumostome. This thesis demonstrates the successful conditioning of na'ive semiintact preparations to show learning in the dish. Furthermore, these conditioned preparations show long-term memory that persists for at least 18 hours. As the neurons that generate this behaviour have been previously identified I can, for the first time, monitor neural activity during both learning and long-term memory consolidation in the same preparation. In particular, I record from the respiratory neuron Right Pedal Dorsal 1 (RPeD 1) which is part of the respiratory central pattern generator. In this study, I demonstrate that preventing RPeDl impulse activity between training sessions reduces the number of sessions needed to produce long-term memory in the present semi-intact preparation.

Some electrical properties of semi-conductor crystals / |nPhyu Phyu Khin. -- 260 St. Catharines, Ont. : [s. n.],

SiC and AtB 12 have been prepared and their resistivities and Hall voltages measured. The resistivities and Hall voltages were measured by the Van der Pauw's method, using spring loaded tungsten contacts. In this method, the major requirement is to have samples of plane parallel surfaces of arbitrary shape with four small contacts at the circumference. Similar measurements were made with a number of SiC crystals obtained from the Norton Research Corporation (Canada)-Ltd., Carolina Aluminum Co., Exolon Co. and Carborundum Co. It was found that resistivity, carrier concentration and mobility of ions depend on the type of impurity. AtB 12 was prepared from the melt containing At and B in the ratio of 4:1. They formed amber-colour pseudo tetragonal crystals. As the crystals obtained were small for electrical measurements, hot pressed lumps have been used to measure their resistivity.

Dictionary of the Zeta Psi Fraternity of North America

A hardcover Dictionary of the Zeta Psi Fraternity, edited by Arthur H. Motley and Harry B. Carpenter. An excerpt from the forward reads: "Having the sincere purpose of placing in the hands of all Brothers of the Fraternity a Directory of the full membership of our order, with addresses as perfectly correct as time and equipment would permit, supplemented with such alphabetical and geographical indices as will make the volume a handy and accurate cross-reference to our membership...". Included with this book is a typewritten letter from Gordon Waldie, treasurer of the Toronto Chapter of the Zeta Psi Fraternity thanking Mrs. Percy Band for the gift of the original initiation certificate of the late Hamilton K. Woodruff. Mr. Woodruff was one of the Charter members of the Fraternity and he was the 7th man initiated into this, the first Canadian chapter of any fraternity. The letter is dated Nov. 21, 1949. The full text is available in the Brock University Special Collections and Archives.

Using PageRank Algorithm in Analyzing Dictionary Graphs and PageRank in Dynamic Graphs

In this thesis we are going to analyze the dictionary graphs and some other kinds of graphs using the PagerRank algorithm. We calculated the correlation between the degree and PageRank of all nodes for a graph obtained from Merriam-Webster dictionary, a French dictionary and WordNet hypernym and synonym dictionaries. Our conclusion was that PageRank can be a good tool to compare the quality of dictionaries. We studied some artificial social and random graphs. We found that when we omitted some random nodes from each of the graphs, we have not noticed any significant changes in the ranking of the nodes according to their PageRank. We also discovered that some social graphs selected for our study were less resistant to the changes of PageRank.