Onset of classical behaviour after a phase transition

We analyze the onset of classical behaviour in a scalar field after a continuous phase transition, in which the system-field, the long wavelength order parameter of the model, interacts with an environment of its own short-wavelength modes. We compute the decoherence time for the system-field modes from the master equation and compare it with the other time scales of the model. Within our approximations the decoherence time is in general the smallest dynamical time scale. Demanding diagonalisation of the decoherence functional produces identical results. The inclusion of other environmental fields makes diagonalisation occur even earlier.Comment: Seven pages, no figures. Contributed talk to the Second International Workshop DICE2004, Piombino, Italy. To be published in the Brazilian Journal of Physic

An Arbitrary Aesthetic: Cultural Reproduction and Hegemonic Canonical Formations in the Western Theatrical Academy

Theatre as an artistic practice has often been celebrated as an art of and for the people, being a modality that in theory the common person has access to learn, explore and experience. In recent years I have become preoccupied with the growing rarification and privileging of this art form, particularly in how it is cognized and taught in the academic world. As such, I set out to investigate the mechanisms at work at levels structural, artistic, and personal that determine how theatre is taught and understood within the western academy. This thesis seeks to examine and unpack the perceived “correct” way to do and teach theatre as posited by the western academic tradition, and the impact this has on its students. I first unpack Pierre Bourdieu’s theories of Cultural Reproduction and Symbolic Violence and their effect on how theatre is understood and produced. I trace the history of theatre in the western academy and the current state of theatre programs and curriculum. I then draw on interviews with individuals who have studied theatre at the undergraduate level to analyze their experience of theatrical pedagogy. In turn, I examine and theorize pedagogical alternatives to encourage a more accessible and individualized approach to performance pedagogy. The result of this thesis is an unpacking of the formations and systems that make up undergraduate theatre performance studies and an analysis of the potentially harmful effects these systems have on the understanding of undergraduate students

The impact of teacher effect on student math competency achievement

Using 4th grade student achievement math scores and Tennessee Value- Added Assessment System (TVAAS) math teacher effectiveness estimates for grades 5-8 (matched to individual students) as predictor variables, this study\u27s purpose was to ascertain the residual and cumulative effects of these teachers on student 9th grade Competency scores. Students from 2 large districts who were 9th graders in the fall of 1997 with complete information were included. From the base model ANOVA, partial sums of squares for teacher estimates for all grades were significant, indicating the presence of residual effects free of partial confounding by other variables: 5th, F=8.75, p-value = 0.0031; 6th, F=14.82, p-value=0.0001: 7th, F=25.75, p-value = 0.0001; 8th, F=73.43, p-value = 0.0001. The differential effect of 5th and 6th grade teachers on 4th grade prior achievement levels produced mean Competency 9th grade scores for students in the bottom quartile ranging from 59-65 (se=0.63 to 0.81), depending on the level of teacher effectiveness students encountered in 5th grade. Competency means for similar low-achieving students assigned to 4 consecutive very ineffective teachers were 53.6 (se=0.733) versus 71.8 (se=.939) for 4 very effective teachers (70 is required for passing). Although a significant ethnic effect was apparent, it paled in comparison to this student Competency score response to 4 similarly effective teachers. Substituting a success variable in place of the grade Competency score as the dependent variable allowed the determination of passing probabilities for various sequences of teachers with each quartile of 4th grade student prior achievement. As the assumed cut score was raised, student passing probability at 9th grade grew increasingly more dependent on 4th grade scores and teacher effectiveness estimates for grades 5-8: F=82.12 at 60 versus 129.83 at 80 (p-values=0.0001). Although all children benefited from highly effective teachers, the lower 50% benefited most. A change in level of effectiveness of teacher sequence increased the probability of passing to at least 50/50 for at least one quartile of students for each assumed cut score. Conclusions: (1) Tennessee\u27s current high stakes student test is holding students accountable for something beyond their control, and the punitive policies associated with it should be reviewed for appropriateness. (2) the availability of effective teachers for lower achieving students is a critical determinant in their ability to pass. (3) Broad variability in teacher effectiveness suggests a need for improved teacher preparation and additional staff development opportunities for practicing teachers with improved accountability measures for teacher preparation

Structural durability of stiffened composite shells

The durability of a stiffened composite cylindrical shell panel is investigated under several loading conditions. An integrated computer code is utilized for the simulation of load induced structural degradation. Damage initiation, growth, and accumulation up to the stage of propagation to fracture are included in the computational simulation. Results indicate significant differences in the degradation paths for different loading cases. The effects of combined loading on structural durability and ultimate structural strength of a stiffened shell are assessed

Mild acute stress improves response speed without impairing accuracy or interference control in two selective attention tasks: Implications for theories of stress and cognition.

Acute stress is generally thought to impair performance on tasks thought to rely on selective attention. This effect has been well established for moderate to severe stressors, but no study has examined how a mild stressor-the most common type of stressor-influences selective attention. In addition, no study to date has examined how stress influences the component processes involved in overall selective attention task performance, such as controlled attention, automatic attentional activation, decision-making, and motor abilities. To address these issues, we randomly assigned 107 participants to a mild acute stress or control condition. As expected, the mild acute stress condition showed a small but significant increase in cortisol relative to the control condition. Following the stressor, we assessed attention with two separate flanker tasks. One of these tasks was optimized to investigate component attentional processes using computational cognitive modeling, whereas the other task employed mouse-tracking to illustrate how response conflict unfolded over time. The results for both tasks showed that mild acute stress decreased response time (i.e., increased response speed) without influencing accuracy or interference control. Further, computational modeling and mouse-tracking analyses indicated that these effects were due to faster motor action execution time for chosen actions. Intriguingly, however, cortisol responses were unrelated to any of the observed effects of mild stress. These results have implications for theories of stress and cognition, and highlight the importance of considering motor processes in understanding the effects of stress on cognitive task performance

Classical Physics and Quantum Loops

The standard picture of the loop expansion associates a factor of h-bar with each loop, suggesting that the tree diagrams are to be associated with classical physics, while loop effects are quantum mechanical in nature. We discuss examples wherein classical effects arise from loop contributions and display the relationship between the classical terms and the long range effects of massless particles.Comment: 15 pages, 3 figure