Time-frequency analysis of chaotic systems

We describe a method for analyzing the phase space structures of Hamiltonian systems. This method is based on a time-frequency decomposition of a trajectory using wavelets. The ridges of the time-frequency landscape of a trajectory, also called instantaneous frequencies, enable us to analyze the phase space structures. In particular, this method detects resonance trappings and transitions and allows a characterization of the notion of weak and strong chaos. We illustrate the method with the trajectories of the standard map and the hydrogen atom in crossed magnetic and elliptically polarized microwave fields.Comment: 36 pages, 18 figure

Mindfulness and emotion in relationships : emotion regulation, empathy, and affect as mediators of the association between mindfulness and relationship satisfaction

With increasing frequency over the past 25 years, mindfulness has been linked with health and psychological wellbeing. Recently it has also been linked with healthy interpersonal relationships. The present cross-sectional study of 331 diverse adults tested a proposed model for understanding the association between mindfulness and relationship satisfaction through the effects of three concepts related to emotion: emotion regulation, empathy and positivity (ratio of positive to negative affect). Perspective taking, a cognitive aspect of empathy, and positivity partially mediated the association between both mindfulness and relationship satisfaction and mindfulness facet nonreactivity and relationship satisfaction. Positivity emerged as the strongest mediator in both cases. Empathic concern, an affective aspect of empathy, was found to be a significant mediator of the association between mindfulness and relationship satisfaction only in individuals with a mindfulness meditation practice and for those with very high levels of emotional awareness. When empathic concern was tested as a mediator of the association between nonreactivity and relationship satisfaction, it was only significant in individuals with high levels of emotional dysregulation

THE PSYCHOLOGICAL IMPACTS OF FALSE POSITIVE OVARIAN CANCER SCREENING: ASSESSMENT VIA MIXED AND TRAJECTORY MODELING

Ovarian cancer (OC) is the fifth most common cancer among women and has the highest mortality of any cancer of the female reproductive system. The majority (61%) of OC cases are diagnosed at a distant stage. Because diagnoses occur most commonly at a late-stage and prognosis for advanced disease is poor, research focusing on the development of effective OC screening methods to facilitate early detection in high-risk, asymptomatic women is fundamental in reducing OC-specific mortality. Presently, there is no screening modality proven efficacious in reducing OC-mortality. However, transvaginal ultrasonography (TVS) has shown value in early detection of OC. TVS presents with the possibility of false positive results which occur when a women receives an abnormal TVS screening test result that is deemed benign following repeat testing (about 7% of the time). The purpose of this dissertation was to evaluate the impact of false positive TVS screening test results on a variety of psychological and behavioral outcomes using mixed and trajectory statistical modeling. The three specific aims of this dissertation were to 1) compare psychological and behavioral outcomes between women receiving normal and false positive results, 2) identify characteristics of women receiving false positive results associated with increased OC-specific distress and 3) characterize distress trajectories following receipt of false positive results. Analyses included a subset of women participating in an experimental study conducted through the University of Kentucky Ovarian Cancer Screening Program. 750 women completed longitudinal assessments: 375 false positive and 375 normal results. Mixed and group-based trajectory modeling were used to evaluate the specific aims. Results suggest women receiving false positive TVS result experience increased OC-specific distress compared to women receiving normal results. Among those receiving false positives, less education, no history of an abnormal screening test result, less optimism and more social constraint were associated with increased OC-specific distress. Family history was associated with increased distress among women with monitoring informational coping styles. Three distinct trajectories characterize the trajectory of distress over a four-month study period. Although decreasing over time, a notable proportion of women experience sustained high levels of OC-specific distress

Heritability and Genetic Gain of Seed Protein, Oil, and Yield among RIL of Soybean

Soybean is a remarkable crop that is used in many aspects of our everyday lives. The seed protein is used primarily for livestock feed, though it is becoming more available as a meat substitute for human consumption. Soybean oil is used in many products such as plastics, foods, and industrial products. Seed yield is the major trait that is selected for in a breeding program. A population of 239 F4 derived RIL from the cross of USG 5601T × U99-310255 was used to calculate heritability estimates by parent offspring regression and on an entry mean basis. This population was grown in 2009 as unreplicated F4:5 plant rows at the East Tennessee Research and Education Center (ETREC) in Knoxville, TN. In 2010, the F4:6 generation was grown as two replications with two locations, ETREC and Highland Rim Research and Education Center (HRREC) in Springfield, TN. In 2011, the F4:7 generation was grown at ETREC, HRREC, and at the Research and Education Center at Milan (RECMLN) in Milan, TN. Averaged over two years (2010 and 2011) and 5 environments exhibited a range of 1928.7 to 3033.6 kg ha-1 with a mean of 2325.7 kg ha-1for seed yield, 398.4 to 451.8 g kg-1 with a mean of 426.8 g kg-1 for seed protein concentration, and 201.1 to 224.6 g kg-1 with a mean of 213.7 g kg-1 seed oil concentration. On an entry mean basis, a heritability estimate of 0.85 for seed protein concentration was observed. However, a parent-offspring regression of F4:6 to F4:7 revealed an estimate of 0.43 (R2= 0.26). For seed oil concentration, heritability estimate on an entry mean basis was 0.78 and the parent-offspring regression was 0.11 (R2=0.01). Seed yield exhibited heritability estimates of 0.23 (R2=0.09) and 0.38 for parent-offspring regression and entry mean basis respectively. Genetic gains were calculated for all traits through selections for the top 5, 10, 15, and 20% of RILs for seed yield, seed protein, and seed oil concentration. Improvements in these traits were achieved singularly and could be selected for multiple traits when phenotypic correlations are considered

The Status of Business-Teacher Education in 20 Selected Negro Degree-Granting Institutions

Thesis (Ed.M.)--Boston Universit

A Computational Procedure to Detect a New Type of High Dimensional Chaotic Saddle and its Application to the 3-D Hill's Problem

A computational procedure that allows the detection of a new type of high-dimensional chaotic saddle in Hamiltonian systems with three degrees of freedom is presented. The chaotic saddle is associated with a so-called normally hyperbolic invariant manifold (NHIM). The procedure allows to compute appropriate homoclinic orbits to the NHIM from which we can infer the existence a chaotic saddle. NHIMs control the phase space transport across an equilibrium point of saddle-centre-...-centre stability type, which is a fundamental mechanism for chemical reactions, capture and escape, scattering, and, more generally, ``transformation'' in many different areas of physics. Consequently, the presented methods and results are of broad interest. The procedure is illustrated for the spatial Hill's problem which is a well known model in celestial mechanics and which gained much interest e.g. in the study of the formation of binaries in the Kuiper belt.Comment: 12 pages, 6 figures, pdflatex, submitted to JPhys

The impact of attrition and non-response in birth cohort studies: a need to incorporate missingness strategies

This paper reveals the extent of attrition in the British Cohort Study begun in 1970 (BCS70) and how it affects sample composition over time. We examine the determinants of response and then construct inverse probability weights (IPWs) to adjust for sample loss. Secondly, we create a hypothetical substantive data set from BCS70 across data collection waves 3 and 4 to illustrate the effectiveness of the use of weights and multiple imputations (MI) in handling the impact of unit non-response and item missingness respectively. Our findings show that when the predictive power of the response models is weak, the efficacy of non- response weights is undermined. Further, multiple imputations are effective in reducing the bias resulting from item missingness when the magnitude of the bias is high and the imputation models are well specified

How consistent is respondent behaviour to allow linkage to health administrative data over time?

This study constitutes the first longitudinal exploration of consent to link survey and administrative data. It relies on a theoretical framework distinguishing between passive, active, consistent and inconsistent consent behaviour. The findings show that, in general, consent behaviours are both passive and consistent. First, consent rates indicate that most respondents behave consistently over time. Secondly, the regression analyses show that for the majority of respondents, consent is not driven by personal convictions but rather depends on the circumstances of the respondent at the time of the interview and on the impact of the interviewers. The findings also show that in longitudinal surveys cross-sectional analyses of consent can be misleading. The changes in the magnitude and in the significance of the results when the temporal dimension of consent is taken into account is a clear indication that consent should be treated as a dynamic phenomenon