Browsing by Subject "Relaxation"
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Item Characteristic relaxation rates of a Bose gas in the classical, quantum and condensed regimes(2011-08) Gust, Erich D.; Reichl, L. E.; Raizen, Mark G.; Gamba, Irene M.; Bohm, Arno; Gleeson, Austin; Niu, QianWe obtain the characteristic relaxation rates and relaxation modes of a Bose gas in three regimes. The classical regime corresponds to a classical gas of hard spheres and the quantum regime corresponds to an interacting quantum Bose gas with no Bose-Einstein condensate present. In the condensed regime a Bose-Einstein condensate is present and modifies the behavior of the gas. In each regime there is a different kinetic equation that describes the evolution of the relevant distribution function. The classical kinetic equation is the Boltzmann equation and the quantum kinetic equation with no condensate present is the Uehling-Uhlenbeck equation. When a condensate is present, we derive a new kinetic equation that describes the evolution of the momentum distribution of Bogoliubov excitations or bogolons. For each of the three kinetic equations, we linearize the collision integral and use it to generate the elements of a collision matrix. The eigenvalues of this matrix give us the characteristic relaxation rates and the eigenvectors give us the relaxation modes. We report numerical results for the eigenvalues in each regime as the particle species, density and temperature of the gas are varied.Item Effect of feedback during relaxation training on repressors and sensitizers(Texas Tech University, 1973-05) Carroll, William MartienNot availableItem The effects of habitat loss and fragmentation caused by woody plant encroachment on native plant diversity and on an invasive grass(2010-05) Alofs, Karen Marie; Fowler, Norma L.; Leibold, Mathew; Parmesan, Camille; Keitt, Timothy; Young, KennethHabitat loss, habitat fragmentation and species invasions have been recognized as three of the leading threats to biodiversity. I examined the effects of habitat loss and fragmentation on native and invasive plants in central Texas. During the last century, the density and abundance of woody plants has been increasing in the savannas of eastern Edwards Plateau. This process, known as woody plant encroachment, not only reduces the amount of open herbaceous habitat but also fragments that habitat creating smaller and more isolated patches. In three studies, I investigated the consequences of this habitat loss and fragmentation for plants which do not occur under the cover of woody plants including native grasses and forbs and the invasive Eurasian bunchgrass, Bothriochloa ischaemum (King Ranch Bluestem). In the first study, I show that woody plant encroachment reduces native herbaceous species richness (the number of species in a given area). Using a collection of historical aerial photographs, I demonstrate that current native herbaceous species richness was most strongly related to recent habitat amount, but to the degree of habitat fragmentation at least 50 years ago. In a second study, I show that the presence of B. ischaemum was negatively related to the degree of fragmentation in the surrounding landscape. Finally, I found that B. ischaemum had higher rates of germination and growth in experimental plots where the species commonly lost with woody plant encroachment were removed than in unmanipulated control plots. Together, this work suggests that woody plant encroachment is directly slowing the spread of an invasive species while indirectly facilitating its establishment.Item Meditation as a treatment for primary dysmenorrhea among women with high and low absorption scores(Texas Tech University, 1983-12) Anderson, Daniel ANot availableItem Novel tools for ultrafast spectroscopy(2011-12) Jarvis, Thomas William; Li, Elaine; Fink, Manfred; Keto, John; Lim, Sang-Hyun; Shih, Chih-Kang; Sitz, GregExciton dynamics in semiconductor nanostructures are dominated by the effects of many-body physics. The application of coherent spectroscopic tools, such as two-dimensional Fourier transform spectroscopy (2dFTS), to the study of these systems can reveal signatures of these effects, and in combination with sophisticated theoretical modeling, can lead to more complete understanding of the behaviour of these systems. 2dFTS has previously been applied to the study of GaAs quantum well samples. In this thesis, we outline a precis of the technique before describing our own experiments using 2dFTS in a partially collinear geometry. This geometry has previously been used to study chemical systems, but we believe these experiments to be the first such performed on semiconductor samples. We extend this technique to a reflection mode 2dFTS experiment, which we believe to be the first such measurement. In order to extend the techniques of coherent spectroscopy to structured systems, we construct an experimental apparatus that permits us to control the beam geometry used to perform four-wave mixing reflection measurements. To isolate extremely weak signals from intense background fields, we extend a conventional lock-in detection scheme to one that treats the optical fields exciting the sample on an unequal footing. To the best of our knowledge, these measurements represent a novel spectroscopic tool that has not previously been described.Item Somatic versus cognitive proccesses in relaxation training: a comparison of the effects of three types of training on somatic versus cognitive anxiety subjects(Texas Tech University, 1982-08) Oringel, Susan EllynNot availableItem Suggestopedia: Its Effects on Word Identification Skills of Mildly and Moderately Retarded Children(Texas Tech University, 1983-05) Hales, Vaughn EricNot Available.Item The effect of sex and type of relaxation training on level of body awareness(Texas Tech University, 1974-06) Pinkston, Michael RayNot availableItem The effectiveness of biofeedback and relaxation procedures in reducing high blood pressure(Texas Tech University, 1975-05) Fidel, EdwardNot availableItem The effects of group relaxation techniques upon student achievement in a general business administration course(Texas Tech University, 1980-05) Miller, BusterNot availableItem The effects of relaxation training and music upon creativity(Texas Tech University, 1981-08) Gamble, James ArthurNot availableItem The modification of psychophysiological responses to stress in piano performance(Texas Tech University, 1984-12) Whitaker, Charlotte SibleyNot availableItem The modification of psychophysiological responses to stress in piano performance(Texas Tech University, 1984-12) Whitaker, Charlotte SibleyNOT AVAILABLE