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Health anxiety and online health information seeking : an experimental study
Full text linkHealth anxiety is a psychological trait that refers to the tendency to experience health-related worries and fears triggered by misinterpretations of bodily sensations as indicative of serious illness. Recent studies have suggested a possible link between health anxiety and online health information seeking (OHIS). It is evident that people with high health anxiety tend to engage in excessive OHIS when noticing unfamiliar bodily symptoms, but often experience negative affect (e.g., worries and fears about health) during or following the search. As a result, they continue to search for more information to reassure themselves. Despite the current knowledge, much remains unknown about the relationship between health anxiety and OHIS.
This dissertation aimed to further explore the relationships between health anxiety and the way people feel (affective), think (cognitive) and act (behavioral) during OHIS. First, I discussed key concepts and theories related to health anxiety and OHIS. Next, I reviewed empirical studies on relationships between health anxiety and the cognitive, affective and behavioral aspect of OHIS. Based on the reviewed theories and empirical studies, I developed a conceptual framework — eHealth Anxiety Model (eHAM). Guided by this model, I proposed a series of research hypotheses which state the relationships between health anxiety and six outcome variables that represent the cognitive (perceived health risk), affective (valence, arousal and control) and behavioral (search effort and search outcome) dimensions of OHIS.
To test these hypotheses, I conducted a quasi-experiment in which participants were asked to perform an online search to find out the most likely diagnosis of an illness case. Results of the quantitative analysis revealed that health anxiety and online search had no statistically significant interaction effect on people’s cognitive, affective and behavioral experience during OHIS. However, health anxiety did have a significant main effect on perceived health risk, valence and search accuracy. To be specific, participants with higher health anxiety perceived greater health risk about the illness case, experienced greater negative affect overall, and were more likely to find the correct diagnosis than those with lower health anxiety.
This dissertation’s theoretical contributions include integrating the theoretical models and concepts from psychology and information science and developing the eHealth Anxiety Model. Results of this study can inform health practitioners and researchers in developing effective interventions for treating online health anxiety.Informatio
Index of University of Rochester Ph. D. Dissertations with Chemistry Department Advisors
No full textList of University of Rochester Ph. D. dissertations from 1933-2009 where the advisor was a Department of Chemistry faculty. This is sorted by author, publication year and advisor.List of University of Rochester Ph. D. dissertations from 1933-2009 where the advisor was a Department of Chemistry faculty. This is sorted by author, publication year and advisor
Ph D or “loadsamoney”?
No full textIt is a brave person who opts for a Ph D after slogging away for a hard-earned first degree. Most of us do it in a vain attempt to continue in a relaxed environment and to become a "Doc". To do a Ph D is to sentence oneself to three more years of poverty, long arduous hours and the stress of writing a thesis, when one could easily go elsewhere and carn "loadsa money" to pay off the overdraft accumulated as an undergraduate. Most Ph D students realise they are used as pawns by their supervisors, in empire-building exercises, in a world where British science is crumbling to its foundations. However, a Ph D can be an enjoyable pursuit, with easy-going attitudes not found outside academia (to stroll in to work late in the morning is just one of the small perks)
Toward Inclusive, Evidence-Based rTMS Care for Patients With Co-Occurring Substance Use Disorders
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Numerical analysis of reproducing kernel collocation method for linear nonlocal models
Full text linkHydraulic fracturing has played a major role in north America's “shale revolution” over the past decades. Modeling of the hydraulic fracture propagation is challenging. Peridynamics, a nonlocal theory of continuum mechanics, has been used to model complex hydraulic fracturing processes in recent years. While the peridynamics-based hydraulic fracturing model has shown promising simulations results, its current numerical discretization lacks any mathematical analysis. This dissertation is motivated by the numerical solution of the peridynamics-based hydraulic fracturing model. The major objective is to develop a robust numerical method, under the change of the modeling parameters, for linear nonlocal diffusion models and peridynamic Navier equation, which are decoupled models of the peridynamics-based hydraulic fracturing model. Reproducing kernel (RK) collocation method is of our interest due to its mesh-free nature. By choosing special RK support sizes, we have developed a RK collocation method for nonlocal models and numerical solutions converge to the nonlocal solution and also to the corresponding local limit independent of the modeling parameters as the nonlocal interactions vanish. Accurate evaluation of the stiffness matrix for nonlocal models is computationally prohibitive even for collocation method. To save computational costs, the concept of RK approximation is generalized to approximate integrals and the quasi-discrete nonlocal operator, which uses a finite number of symmetric quadrature points to evaluate the integral, is proposed. We have shown RK collocation on the quasi-discrete nonlocal diffusion and peridynamic Navier equation converge to their classical counterparts. Finally, for the pure displacement form of the classical linear elasticity model, finite element solutions deteriorate when the material is nearly incompressible. A common remedy is to introduce an additional variable, pressure, and rewrite the equation in a mixed formulation, but the discrete functional spaces need to satisfy the famous inf-sup condition. For the the mixed form of the quasi-discrete peridynamic Navier equation, the discretization obtained using RK collocation with equal order interpolation for displacements and pressure passes the inf-sup test; the solution does not suffer from instability. Hence, with the use of penalty techniques or artificial compressibility, the proposed RK collocation method is promising in solving the peridynamics-based hydraulic fracturing model, which has an embedded saddle-point problemPetroleum and Geosystems Engineerin
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Quantum Boltzmann dynamics around the Fermi ball
No full textIn this thesis, we study a cold gas of N ≫ 1 weakly interacting fermions. We describe the time evolution of states that are perturbations of the Fermi ball, and analyze the dynamics in particle-hole variables. Our main result states that, for small values of the coupling constant and for appropriate initial data, the effective dynamics of the momentum distribution is determined by a discrete collision operator of quantum Boltzmann form.Mathematic
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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Data-driven drilling optimization and field development in unconventionals
Full text linkLeveraging the better availability of drilling data, this dissertation explores ways and opportunities to optimize the drilling process and field development through data analytics in the Permian and Williston Basin shale fields. Unlike traditional wells, unconventional wells share similar well design, are drilled in close proximity, and require high directional execution precision. A large number of wells need to be drilled, so the relatively thin margins per well demand high efficiency and low variance operation, especially in the current low oil price environment. This study addresses these challenges in three ways, using a more accurate physics-based model, a real-time assessment/advisory system, and a value-oriented (asymmetric) optimization strategy. The first part of this dissertation presents a thorough investigation and refresh of the Mechanical Specific Energy (MSE) and Confined Compressive Strength (CCS) model, because after enjoying past success and popularity, the current MSE/CCS model has become inadequate for modern unconventional drilling. It omits some important, well-known components and corrections, which are essential in today’s operations. Though it has been powerful and popular in the past, its completeness and physical validity have always being questionable. In addition, the popularization of the mud motor (PDM), which is powered by hydraulic energy, now magnifies these problems. The classic MSE equation badly needs an update to suit the needs in current unconventional drilling. This study proposes a new two-tier system of surface and downhole MSE to address these issues; it also examines all components, corrections, and factors known to affect MSE/CCS with data from the Bakken and the Permian fields, providing an updated iteration with more scientific rigor and physical justification. The second part of this dissertation conducts a case study of tracking and removing Non-Productive Time (NPT) and Invisible Lost Time (ILT), leveraging data analytics techniques with a value-oriented asymmetric approach. Process discretization is introduced to transform the continuous drilling process into individual standardized tasks to expose NPT and ILT buried in the process. Best practices are identified through rig-to-rig comparison and then implemented to the entire fleet to scale up the benefit. Furthermore, to overcome the potential limitation/risk posed by relying on an individual flagship rig as a benchmark, a dedicated test rig/digital twining system is recommended to test and push technical limits. After defines technical limit in a systematic manner, the author proposes future plans to develop thoughtful, robust, implementable, and sustainable Standard Operating Procedures (OPS) for each individual taskPetroleum and Geosystems Engineerin
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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