11 resultados para Limit of meaning of a Scientific Theory

em Brock University, Canada


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The Lennard-Jones Devonshire 1 (LJD) single particle theory for liquids is extended and applied to the anharmonic solid in a high temperature limit. The exact free energy for the crystal is expressed as a convergent series of terms involving larger and larger sets of contiguous particles called cell-clusters. The motions of all the particles within cell-clusters are correlated to each other and lead to non-trivial integrals of orders 3, 6, 9, ... 3N. For the first time the six dimensional integral has been calculated to high accuracy using a Lennard-Jones (6-12) pair interaction between nearest neighbours only for the f.c.c. lattice. The thermodynamic properties predicted by this model agree well with experimental results for solid Xenon.

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The purpose ofthis study was to investigate the emotion assumptions underlying just-world theory. This theory proposes that people have a need to believe in a just world - a world where people get what they deserve. The first emotion assumption is that people, therefore, find injustices (Le., undeserved outcomes) threatening and thus emotionally arousing. Second, it is this arousal that is assumed to drive subsequent strategies for maintaining the belief in a just world. One strategy an individual may use to maintain this belief is derogating victims of injustice, or seeing their character in a more negative light. To test these two assumptions, 102 participants viewed a video depicting either a victim who presumably presented a high threat to people's belief in ajust world (she was innocent and, therefore, undeserving of her fate) or low threat (she was not innocent and, therefore, more deserving of her fate) while their heart rate and EDA was measured. Half of the participants were then given the opportunity to help the victim whereas the other half were not given this opportunity. The manipulations were followed by both explicit and indirect measures of evaluations ofthe victim as well as self-report measures of affect experienced while watching the victim video, and an individual difference scale assessing the strength of participants' just-world beliefs (as well as other measures that were part ofa larger study). Results indicated that participants did report feeling more threatened by the innocent victim. Although there was some evidence of victim derogation on the implicit measure of victim evaluation, there was no evidence that emotional arousal drove the negative evaluations of the victim who could not be helped. Some interaction effects with individual differences in just-world beliefs did occur, but these were not entirely consistent with the rationale behind the individual difference scales. These results provide only weak support for the first emotion assumption ofjust-world theory. Implications of these findings as well as limitations of the study and future directions concerning just-world theory are discussed.

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A cognitively based instructional program for narrative writing was developed. The effects of using cognitively based schematic planning organizers at the pre-writing stage were evaluated using subjects from the Primary, Junior and Intermediate divisions. Results indicate that the use of organizers based on problem solving significantly improved the organization and the overall quality of narrative writing for students in grades 3, 6 and 7. The magnitude of the improvement of the treatment group over the control group performance in Organization ranged from 10.7% to 22.9%. Statistical and observational data indicate many implications for further research into the cognitive basis for writing and reading; for the improvement and evaluation of school writing programs; for the design of school curricula; and for the inservice education for teachers of writing.

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Background: This study examined three social factors (i.e., autonomy support, structure, and involvement) and their relationship with the motivational processes proposed by Vallerand ( 1 997). This study explored sources of support for exercise participation. -~ ' Methods: Participants (N = 425) completed self-reported instruments which assessed variables outlined within Vallerand's ( 1 997) HMIEM. Results: Structural equation modeling analyses predicting the cognitive/affective and exercise behaviour accounted for 23 percent of variance in positive affect, 10 percent of variance in negative affect, 38 percent of variance in physical self-concept, and 4 percent of variance in exercise behaviour. Exploratory analyses revealed that friends, romantic partners, and educators to be consistent sources for providing autonomy support, structure, and involvement, f !,< r - r* Summary: This study is among the first to examine perceived sources oi autonomy support, structure, and involvement from friends in the exercise context and suggest such perceptions may contribute to motivating exercise behaviour in post-secondary students.

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A generalization to the BTK theory is developed based on the fact that the quasiparticle lifetime is finite as a result of the damping caused by the interactions. For this purpose, appropriate self-energy expressions and wave functions are inserted into the strong coupling version of the Bogoliubov equations and subsequently, the coherence factors are computed. By applying the suitable boundary conditions to the case of a normal-superconducting interface, the probability current densities for the Andreev reflection, the normal reflection, the transmission without branch crossing and the transmission with branch crossing are determined. Accordingly the electric current and the differential conductance curves are calculated numerically for Nb, Pb, and Pb0.9Bi0.1 alloy. The generalization of the BTK theory by including the phenomenological damping parameter is critically examined. The observed differences between our approach and the phenomenological approach are investigated by the numerical analysis.

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The study purpose was to examine differences between competitive and recreational weight trainers on indices of motivation, goals and behaviour. Data was collected from a purposive sample of competitive (n = 177; Mage = 30.86; SDage = 11.35) and recreational (n = 196; Mage = 21.97; SDage = 6.05) weight trainers using a cross-sectional, non-experimental design. Participants completed the Behavioural Regulation in Exercise Questionnaire-2R, Exercise Motivations Inventory-2, assessment of weight training behaviour and demographic questions. Multivariate analyses of variance indicated higher endorsement of autonomous motives and mostly intrinsically-oriented goals, while independent samples t-tests indicated higher frequency of weight training behaviour among the competitive weight trainers. Group differences were independent of demographic factors. Findings suggest that autonomous motives and intrinsic goals may not be undermined by competition among competitive weight trainers. This study also provides support for the utility of organismic integration theory and goal contents theory in examining strength-based exercise.

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There is a signature on this book that reads "Julia Cleveland 22 East-8 Street, Erie Penna."

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We have calculated the thermodynamic properties of monatomic fcc crystals from the high temperature limit of the Helmholtz free energy. This equation of state included the static and vibrational energy components. The latter contribution was calculated to order A4 of perturbation theory, for a range of crystal volumes, in which a nearest neighbour central force model was used. We have calculated the lattice constant, the coefficient of volume expansion, the specific heat at constant volume and at constant pressure, the adiabatic and the isothermal bulk modulus, and the Gruneisen parameter, for two of the rare gas solids, Xe and Kr, and for the fcc metals Cu, Ag, Au, Al, and Pb. The LennardJones and the Morse potential were each used to represent the atomic interactions for the rare gas solids, and only the Morse potential was used for the fcc metals. The thermodynamic properties obtained from the A4 equation of state with the Lennard-Jones potential, seem to be in reasonable agreement with experiment for temperatures up to about threequarters of the melting temperature. However, for the higher temperatures, the results are less than satisfactory. For Xe and Kr, the thermodynamic properties calculated from the A2 equation of state with the Morse potential, are qualitatively similar to the A 2 results obtained with the Lennard-Jones potential, however, the properties obtained from the A4 equation of state are in good agreement with experiment, since the contribution from the A4 terms seem to be small. The lattice contribution to the thermal properties of the fcc metals was calculated from the A4 equation of state, and these results produced a slight improvement over the properties calculated from the A2 equation of state. In order to compare the calculated specific heats and bulk moduli results with experiment~ the electronic contribution to thermal properties was taken into account~ by using the free electron model. We found that the results varied significantly with the value chosen for the number of free electrons per atom.

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Four problems of physical interest have been solved in this thesis using the path integral formalism. Using the trigonometric expansion method of Burton and de Borde (1955), we found the kernel for two interacting one dimensional oscillators• The result is the same as one would obtain using a normal coordinate transformation, We next introduced the method of Papadopolous (1969), which is a systematic perturbation type method specifically geared to finding the partition function Z, or equivalently, the Helmholtz free energy F, of a system of interacting oscillators. We applied this method to the next three problems considered• First, by summing the perturbation expansion, we found F for a system of N interacting Einstein oscillators^ The result obtained is the same as the usual result obtained by Shukla and Muller (1972) • Next, we found F to 0(Xi)f where A is the usual Tan Hove ordering parameter* The results obtained are the same as those of Shukla and Oowley (1971), who have used a diagrammatic procedure, and did the necessary sums in Fourier space* We performed the work in temperature space• Finally, slightly modifying the method of Papadopolous, we found the finite temperature expressions for the Debyecaller factor in Bravais lattices, to 0(AZ) and u(/K/ j,where K is the scattering vector* The high temperature limit of the expressions obtained here, are in complete agreement with the classical results of Maradudin and Flinn (1963) .

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We have calculated the equation of state and the various thermodynamic properties of monatomic fcc crystals by minimizing the Helmholtz free energy derived in the high temperature limit for the quasiharmonic theory, QH, and the lowest-order (cubic and quartic), 'A2, anharmonic terms of the perturbation theory, PT. The total energy in each case is obtained by adding the static energy. The calculation of the thermal properties was carried out for a nearest-neighbour central-force model of the fcc lattice by means of the appropriate thermodynamic relations. We have calculated the lattice constant, the thermal expansion, the coefficient of volume expansion, the specific heat at constant volume and at constant pressure, the isothermal and adiabatic bulk moduli, and the Griineisen parameter, for the rare-gas solids Kr and Xe, and gold. Morse potential and modified Morse potential were each used to represent the atomic interaction for the three fcc materials. For most of the calculated thermodynamic properties from the QH theory, the results for Kr and Xe with the modified Morse potential show an improvement over the results for the Morse potential when compared with the experimental data. However, the results of the 'A 2 equation of state with the modified Morse potential are in good agreement with experiment only in the case of the specific heat at constant volume and at constant pressure. For Au we have calculated the lattice contribution from the QH and 'A 2 PT and the electronic contribution to the thermal properties. The electronic contribution was taken into account by using the free electron model. The results of the thermodynamic properties calculated with the modified Morse potential were similar to those obtained with the Morse potential. U sing the minimized equation of state we also calculated the Mossbauer recoilless fraction for Kr and Xe and the Debye-Waller factor (DWF) for Pb, AI, eu, Ag, and Au. The Mossbauer recoilless fraction was obtained for the above two potentials and Lennard-Jones potential. The L-J potential gives the best agreement with experiment for Kr. No experimental data exists for Xe. At low temperature the calculated DWF results for Pb, AI, and eu show a good agreement with experimental values, but at high temperature the experimental DWF results increase very rapidly. For Ag the computed values were below the expected results at all temperatures. The DWF results of the modified Morse potential for Pb, AI, eu and Ag were slightly better than those of the Morse potential. In the case of Au the calculated values were in poor agreement with experimental results. We have calculated the quasiharmonic phonon dispersion curves for Kr, Xe, eu, Ag, and Au. The calculated and experimental results of the frequencies agree quite well for all the materials except for Au where the longitudinal modes show serious discrepancies with the experimental results. In addition, the two lowest-order anharmonic contributions to the phonon frequency were derived using the Green's function method. The A 2 phonon dispersion curves have been calculated only for eu, and the results were similar to those of the QH dispersion curves. Finally, an expression for the Griineisen parameter "( has been derived from the anharmonic frequencies, and calculated for these materials. The "( results are comparable with those obtained from the thermodynamic definition.

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The purpose of this research study was to develop a conceptual model through the use of a grounded theory approach, which explains how trigger events are related to leadership development. Trigger events are experience that cause developmental growth and may result in an increased ability to lead (Luthans and Avolio (2003). In this study, there were two phases of data collection. First participants completed the Washington University Sentence Completion Test (WUSCT), where their respective leadership developmental stage was measured. Second, participants were involved in two in-depth interviews where an understanding was reached as to how various trigger events have impacted their leadership development. From these data, a conceptual model was developed to explain the relationship between trigger events and leadership development. Participants described trigger events as being important developmental periods, during which time they grew as people and became more capable leaders.