Doctor of Philosophy

dissertationA significant percentage of clients entering counseling or psychotherapy unilaterally discontinue after the first or second session. In the clinical and research literature these former clients are referred to as "early premature terminators" (EPTs) and are often presumed to be treatment failures. While considerable research has been performed regarding EPTs, very few studies have actually contacted this difficult- to-reach population. A group of former clients from The University of Utah Counseling Center (UCC) who met EPT criteria participated in this study. A semistructured interview was employed to examine the participants' perceptions of various aspects of their termination. Interviews were transcribed and analyzed for themes using a qualitative verbal data analysis process called the Constant Comparison Method. Emergent themes from the data concerned participants' perceptions and evaluations of UCC and their overall counseling experience, including perceptions of their counselor. Additional themes from the data included factors related to early termination and the processes associated with ending counseling. Most participants reported generally favorable counseling experiences and indicated they made progress and felt a diminished need to continue counseling. Some identified personality variables they believed were also associated with ending counseling when and how they did. The researcher incorporated these major themes into a data-based grounded theory of early termination. This theory holds that people who meet EPT criteria may actually perceive greater early progress in counseling (with an attendant sense of diminished counseling need) relative to the perceived "costs" of counseling than do clients who persist in counseling for a longer period. The findings and conclusions of the study, as distilled in the grounded theory, provide a new and different data-generated conceptual framework to guide and shape subsequent inquiry and practice in this area

Red Sequence Cluster Finding in the Millennium Simulation

We investigate halo mass selection properties of red-sequence cluster finders using galaxy populations of the Millennium Simulation (MS). A clear red sequence exists for MS galaxies in massive halos at redshifts z < 1, and we use this knowledge to inform a cluster-finding algorithm applied to 500 Mpc/h projections of the simulated volume. At low redshift (z=0.4), we find that 90% of the clusters found have galaxy membership dominated by a single, real-space halo, and that 10% are blended systems for which no single halo contributes a majority of a cluster's membership. At z=1, the fraction of blends increases to 22%, as weaker redshift evolution in observed color extends the comoving length probed by a fixed range of color. Other factors contributing to the increased blending at high-z include broadening of the red sequence and confusion from a larger number of intermediate mass halos hosting bright red galaxies of magnitude similar to those in higher mass halos. Our method produces catalogs of cluster candidates whose halo mass selection function, p(M|\Ngal,z), is characterized by a bimodal log-normal model with a dominant component that reproduces well the real-space distribution, and a redshift-dependent tail that is broader and displaced by a factor ~2 lower in mass. We discuss implications for X-ray properties of optically selected clusters and offer ideas for improving both mock catalogs and cluster-finding in future surveys.Comment: final version to appear in MNRAS. Appendix added on purity and completeness, small shift in red sequence due to correcting an error in finding i

Dynamical Masses of RCS Galaxy Clusters

A multi-object spectroscopy follow-up survey of galaxy clusters selected from the Red-sequence Cluster Survey (RCS) is being completed. About forty clusters were chosen with redshifts from 0.15 to 0.6, and in a wide range of richnesses. One of the main science drivers of this survey is a study of internal dynamics of clusters. We present some preliminary results for a subset of the clusters, including the correlation of optical richness with mass, and the mass-to-light ratio as a function of cluster mass.Comment: 5 pages, 5 figures, to appear in the Proceedings of IAU Colloquium 195: "Outskirts of Galaxy Clusters: intense life in the suburbs", Torino Italy, March 200

Automated Laser Scatter Detection of Near-Surface Defects and Machining Damage in Ceramic Components

The need to achieve higher gas firing temperatures in new stationary gas turbines has led to the requirement for stronger, longer-lasting materials capable of functioning in environments more severe than traditional materials permit. The higher operating temperatures seen in these environments (\u3e1300 °C) would substantially increase energy efficiency and reduce emissions. Because conventional materials are not suitable, alternate materials are being considered for turbine components. Included among these are the Si3N4 ceramics. In an effort to improve and extend the working lifetime of the components, improvement in the detection of critical defects (such as cracks, voids, inclusions, or microstructural variations) in their surface and near-subsurface regions is being investigated. Although all of the defects can occur either during manufacturing or in operation, the specific type of defect most likely to occur in a given component depends on a various factors, including the material system, processing and machining parameters, component geometry, and application environment

A z=0.9 supercluster of X-ray luminous, optically-selected, massive galaxy clusters

We report the discovery of a compact supercluster structure at z=0.9. The structure comprises three optically-selected clusters, all of which are detected in X-rays and spectroscopically confirmed to lie at the same redshift. The Chandra X-ray temperatures imply individual masses of ~5x10^14 Msun. The X-ray masses are consistent with those inferred from optical--X-ray scaling relations established at lower redshift. A strongly-lensed z~4 Lyman break galaxy behind one of the clusters allows a strong-lensing mass to be estimated for this cluster, which is in good agreement with the X-ray measurement. Optical spectroscopy of this cluster gives a dynamical mass in good agreement with the other independent mass estimates. The three components of the RCS2319+00 supercluster are separated from their nearest neighbor by a mere <3 Mpc in the plane of the sky and likely <10 Mpc along the line-of-sight, and we interpret this structure as the high-redshift antecedent of massive (~10^15 Msun) z~0.5 clusters such as MS0451.5-0305.Comment: ApJ Letters accepted. 5 pages in emulateapj, 3 figure

Serial MR diffusion to predict treatment response in high-grade pediatric brain tumors: a comparison of regional and voxel-based diffusion change metrics

Background Assessment of treatment response by measuring tumor size is known to be a late and potentially confounded response index. Serial diffusion MRI has shown potential for allowing earlier and possibly more reliable response assessment in adult patients, with limited experience in clinical settings and in pediatric brain cancer. We present a retrospective study of clinical MRI data in children with high-grade brain tumors to assess and compare the values of several diffusion change metrics to predict treatment response. Methods Eighteen patients (age range, 1.9–20.6 years) with high-grade brain tumors and serial diffusion MRI (pre- and posttreatment interval range, 1–16 weeks posttreatment) were identified after obtaining parental consent. The following diffusion change metrics were compared with the clinical response status assessed at 6 months: (1) regional change in absolute and normalized apparent diffusivity coefficient (ADC), (2) voxel-based fractional volume of increased (fiADC) and decreased ADC (fdADC), and (3) a new metric based on the slope of the first principal component of functional diffusion maps (fDM). Results Responders (n = 12) differed significantly from nonresponders (n = 6) in all 3 diffusional change metrics demonstrating higher regional ADC increase, larger fiADC, and steeper slopes (P < .05). The slope method allowed the best response prediction (P < .01, η2 = 0.78) with a classification accuracy of 83% for a slope of 58° using receiver operating characteristic (ROC) analysis. Conclusions We demonstrate that diffusion change metrics are suitable response predictors for high-grade pediatric tumors, even in the presence of variable clinical diffusion imaging protocols

How Low Can You Go? Feature Selection for Drug Discovery

The cost of bringing a drug to market depends on how quickly a candidate drug can be “discovered” and evaluated to ensure safety and effectiveness. In this work we develop a method for predicting whether a given drug and protein compound will “bind.” Our aim is to select a set of features to predict drug-protein interactions. This study focuses on kinases. Kinase inhibitors are the largest class of new cancer therapies. Selective inhibition is difficult due to high sequence similarity, leading to off-target interactions and side-effects. Pictured here human c-SRC

A Linearization Beam-Hardening Correction Method for X-Ray Computed Tomographic Imaging of Structural Ceramics

Computed tomographic (CT) imaging with both monochromatic and polychromatic x-ray sources can be a powerful NDE method for characterization (e. g., measurement of density gradients) as well as flaw detection (e. g., detection of cracks, voids, inclusions) in ceramics. However, the use of polychromatic x-ray sources can cause image artifacts and overall image degradation through beam hardening (BH) effects [1]. Beam hardening occurs because (i) x-ray attenuation in a given material is energy dependent and (ii) data collection in CT systems is not energy selective. Without an appropriate correction, the BH effect prevents the establishment of an absolute scale for density measurement. Thus, quantitative density comparisons between samples of the same material but of different geometrical shape becomes unreliable [2]

The future of employee development

A series of trends shaping the current workplace has changed the nature of human capital development practice to be more employee-driven. However, existing development research does not fully account for this shift and the anticipated benefits of employee-driven development. In this review we reflect on the current state of the employee development literature and propose a new, broader conceptualization of employee development characterized by a partnership between the employer and employee. In doing so, we offer three recommendations for how research needs to evolve to align employee development scholarship with current practices: (1) incorporate proactivity in the definition of employee development, (2) update the context for learning, and, (3) think differently about how human capital is valued. We suggest ways in which theory can be extended for increasing our understanding of several commonly used employee-driven development methods. Finally, we provide future research questions and practical suggestions based on our new conceptualization of employee development