Browsing by Subject "longitudinal study"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item An Approach to Nonparametric Bayesian Analysis for High Dimensional Longitudinal Data Sets(2016-06) Shang, KanThe goal of this thesis is to develop a more powerful and flexible nonparametric method for the analysis of longitudinal data arising from high throughput biological assays, such as arise in next generation sequence analysis, proteomics and metabolomics, by expanding on an existing approach. The method compared 2 groups by testing for differences in the time to upcrossings and downcrossings for all possible levels using standard nonparametric statistical methods for testing for differences between event times that are subject to censoring. The main problem with nonparametric approaches is their lack of power relative to parametric alternatives, hence methods that aim to redress the shortcomings of nonparametric methods would provide researchers with an approach that greatly enhances their ability to analyze data sets that have a potential impact on human health. Hence in this thesis, we first develop a Bayesian counterpart to rank based tests using the Dirichlet process mixture (DPM) prior. Then we expand this approach to tie sets of distinct level crossing problems together via a hierarchical model to develop a more powerful test. While focusing on the first passage time is useful, such an approach ignores data beyond the first passage time. Hence, we also explore the analysis of recurrent event data from a Bayesian semi-parametric perspective and examine under what conditions the consideration of recurrent events leads to a more powerful procedure. There are not universally agreed upon methods for nonparametric longitudinal analysis, especially in a high dimensional context. As such the thesis research could help fill this gap in the field.Item Fruit Herbivory on Individual Plants in Long-Term Study of Population Dynamics of Clarkia xantiana ssp. xantiana at 26 sites in the Kern River Valley, California, USA from 2001 to 2015(2017-07-28) Moeller, David; Geber, Monica A; Eckhart, Vince M; moeller@umn.edu; Moeller, DavidDocumentation of fruit herbivory on individual plants in long-term study of population dynamics of Clarkia xantiana ssp. xantiana at 26 sites in the Kern River Valley, California, USA from 2001 to 2015.Item Fruiting Plant Number in Long-term Study of Population Dynamics of Clarkia xantiana ssp. xantiana at 35 Populations in the Kern River Valley, California, USA from 2006 to 2017(2017-07-25) Moeller, David; Geber, Monica A; Eckhart, Vince M; moeller@umn.edu; Moeller, DavidDocumentation of data collected on fruiting plant number per 0.5m2 in long-term study of population dynamics of Clarkia xantiana ssp. xantiana at 35 populations in the Kern River Valley, California, USA from 2006 to 2017Item Intraindividual Variability in Personality Research: Considering Time, Measurement, and the Interpersonal Context(2024-05) Nguyen, Le Phuong LinhPersonality research has established robust associations between traits and a variety of life outcomes. Nevertheless, much of the literature relies on the Big Five traits, which broadly encapsulate important patterns of psychological individual differences. As a result, this broad conceptualization often leads to weaker associations with outcomes within specific domains. The current dissertation offers a comprehensive examination of different ways to expand upon traditional trait research. This includes combining multiple levels of personality constructs both within and outside of the Big Five framework, multiple perspectives through self and informant reports, and multiple timescales from one-time trait measures to dynamic state fluctuations and longitudinal trait changes. The primary focus is on intraindividual variability, or how people change in their psychological processes across time, and its relevance within the highly influential life domain of romantic relationships. Study 1 presents a preregistered meta-analytic review across k = 88 independent samples (N = 20,813) of the association between personality traits at both the domain (Big Five) and metatrait (Stability and Plasticity) levels with affective variability. We found a positive association between affective variability and Plasticity as well as its underlying traits. However, the pattern of findings was mixed and valence-specific for the Stability traits, and this metatrait itself was negatively associated with variability in Positive Affect but positively so for variability in Negative Affect. Study 2 further investigated intraindividual variability in psychological processes by examining assortative mating patterns in 138 established romantic couples using experience sampling methods of personality and affective states across 35 time points during a 7-day period. We found evidence for assortative mating based on both baseline traits and dynamic states. However, there was more evidence for perceived similarities than actual similarities at baseline, and there was much more evidence for dynamic similarities on states than baseline similarities on traits. There was also evidence for a complementarity effect or negative between-partner correlation on Volatility. Study 3 expanded the timescale from dynamic short-term state fluctuations to longitudinal trajectories of trait change across multiple months and years, examining assortative mating patterns in two complementary samples of early dating couples (N = 184) and married or cohabiting couples (N = 168). We found evidence for assortative mating across various relationship-specific characteristics both at baseline and longitudinally, which were often stronger in magnitude than assortment on Big Five traits. Consistent with Study 2, couples often perceived each other to be more similar than their actual similarity indicated. Nonetheless, in line with the literature, there was little evidence to support the benefits of between-partner similarity for relationship quality, especially after controlling for actor and partner effects of both partners’ individual characteristics. Altogether, this research program provides a broad and thorough examination of intraindividual variability in general as well as in the interpersonal context, and in doing so contributes to both the substantive body of literature and the methodological considerations needed when investigating these personality processes.Item Site Characteristics and Climate in Long-Term Study of Population Dynamics of Clarkia xantiana ssp. xantiana at 35 Sites in the Kern River Valley, California, USA from 2006 to 2017(2017-07-25) Moeller, David A; Geber, Monica A; Eckhart, Vince M; moeller@umn.edu; Moeller, David ASite locations and environmental variables of 35 populations of Clarkia xantiana ssp. xantiana where plant density and fruit production have been measured in a long term demographic study.