This study aims to better understand factors associated with audit office closures and how the risk of office closure relates to audit outcomes, including audit quality and fees. Factors associated with office closure include small office size, lower office growth, proximity to regulators, unfavorable local economic changes, client losses, and lack of recent local office closures. The main analysis does not find evidence of a relationship between closure risk and audit quality but suggests that offices with a higher closure risk charge higher audit fees per client compared to offices with lower closure risk. Results also suggest that clients who change audit firms following closure of their auditor's office enjoy higher quality and lower fees compared to those clients who change offices but remain with the same firm following closure. These audit quality results cannot be explained by clients switching to Big 4 auditors, industry specialists, or to more geographically proximate offices. Instead, these results suggest a fresh look benefit by the new audit firm. Additionally, the audit fee discount enjoyed by these clients diminishes over time as the fees for these clients increase more quickly than for those clients that change offices following closure. / Doctor of Philosophy / This study aims to better understand factors associated with audit firm office closures and how the risk of closure for non-closed offices relates to audit outcomes, including audit quality and fees. Factors associated with office closure include small office size, lower office growth, proximity to regulators, unfavorable local economic changes, client losses, and lack of recent local office closures. The main analysis does not find evidence of a relationship between closure risk and audit quality but suggests that offices with a higher closure risk charge higher audit fees per client compared to offices with lower closure risk. Results also suggest that clients who change audit firms following closure of their auditor's office enjoy higher quality and lower fees compared to those clients who change offices but remain with the same firm following closure.

Let K=Q(theta) be the algebraic number field formed by adjoining theta to the rationals where theta is a real root of an irreducible monic cubic polynomial f(x) in Z[x]. If theta is not the cube root of a rational integer, we call the field K a non-pure cubic field, and if K doesn't contain the conjugates of theta, we call K a non-normal cubic field. A method described by Martinet and Payan allows us to construct such fields from elements of a quadratic field. In this work, we examine such non-normal, non-pure cubic fields and their normal closures, using algorithms in Mathematica to compute various invariants of these fields. In addition, we prove general results relating the ranks of the ideal class groups of the rings of integers of these cubic fields to those of their normal closures. / Ph. D.

The work in this thesis is concerned with the mechanics of the initiation and growth of small fatigue cracks from notches under service load histories. Fatigue life estimates for components subjected to variable amplitude service loading are usually based on the same constant amplitude strain-life data used for constant amplitude fatigue life predictions. The resulting fatigue life estimates although they are accurate for constant amplitude fatigue, are always non conservative for variable amplitude load histories. Similarly fatigue life predictions based on small crack growth calculations for cracks growing from flaws in notches are non conservative when constant amplitude crack growth data are used. These non conservative predictions have, in both cases, been shown to be due to severe reductions in fatigue crack closure arising from large (overload or underload) cycles in a typical service load history. Smaller load cycles following a large near yield stress overload or underload cycle experience a much lower crack opening stress than that experienced by the same cycles in the reference constant amplitude fatigue tests used to produce design data. This reduced crack opening stress results in the crack remaining open for a larger fraction of the stress-strain cycle and thus an increase in the effective portion of the stress-strain cycle. The effective strain range is increased and the fatigue damage for the small cycles is greater than that calculated resulting in a non conservative fatigue life prediction. Previous work at Waterloo introduced parameters based on effective strain-life fatigue data and effective stress intensity versus crack growth rate data. Fatigue life calculations using these parameters combined with experimentally derived crack opening stress estimates give accurate fatigue life predictions for notched components subjected to variable amplitude service load histories. Information concerning steady state crack closure stresses, effective strain-life data, and effective stress intensity versus small crack growth rate data, are all obtained from relatively simple and inexpensive fatigue tests of smooth specimens in which periodic underloads are inserted into an otherwise constant amplitude load history. The data required to calibrate a variable amplitude fatigue crack closure model however, come from time consuming measurements of the return of crack closure levels for small cracks to a steady state level following an underload (large cracks for which crack closure measurements are easier to make cannot be used because at the high stress levels in notches under service loads a test specimen used would fracture). For low and moderately high hardness levels in metals crack growth and crack opening stress measurements have been made using a 900x optical microscope for the small crack length at which a test specimen can resist the high stress levels encountered when small cracks grow from notches. For very hard metals the crack sizes may be so small that the measurements must be made using a confocal scanning laser microscope. In this case the specimen must be removed from the test machine for each measurement and the time to acquire data is only practical for an extended research project. The parameters for the crack closure model relating to steady state crack closure levels vary with material cyclic deformation resistance which in turn increases with hardness. One previous investigation found that the steady state crack opening level was lower and the recovery to a steady state crack opening stress level after an underload was more rapid for a hard than for a soft metal. This observation can be explained by the dependence of the crack tip plastic zone size that determines crack tip deformation and closure level on metal hardness and yield strength. Further information regarding this hypothesis has been obtained in this thesis by testing three different steels of varying hardness levels (6 HRC, 35 HRC, and 60 HRC) including a very hard carburized steel having a hardness level (60 HRC) for which no crack opening stress data for small cracks had yet been obtained. This thesis introduced a new test procedure for obtaining data on the return of crack opening stress to a steady state level following an underload. Smooth specimens were tested under load histories with intermittent underload cycles. The frequency of occurrence of the underloads was varied and the changes in fatigue life observed. The changes in damage per block (the block consisted of an underload cycle followed by intermittent small cycles) were used to determine the value of the closure model parameter governing the recovery of the crack opening stress to its steady state level. Concurrent tests were carried out in which the crack opening stress recovery was measured directly on crack growth specimens using optical microscope measurements. These tests on metals ranging in hardness from soft to very hard were used to assess whether the new technique would produce good data for crack opening stress changes after underloads for all hardness levels. The results were also used to correlate crack closure model parameters with mechanical properties. This together with the steady state crack opening stress, effective strain-life data and the effective intensity versus crack growth rate data obtained from smooth specimen tests devised by previous researchers provided all the data required to calibrate the two models proposed in this investigation to perform strain-life and small crack growth fatigue analysis.

Patients of stoma caused by the colorectal disease or trauma are increasing and most of the patients are keen to have their stoma closed as early as possible to lower the burdens in their life. However, stoma often associated with complications such as wound. The interval between constructing and closing of stoma is still controversial. This study will figure out a way to predict an appropriate timing of stoma closure to get better outcome by using NHI database, from January 1, 2007 to December 31, 2008, in Taiwan. In 463 stoma closure patients, mean age: 65.94 years, ratio of male to female: 1.66, 70.19% Colostomy, 29.81% Ileostomy, mean timing: 156.73 days, mean length of stay: 10.81 days, mean fees: 57,698.06 TWD, only one death in hospital, 35 readmission within 30 days after discharged; with £\ = 0.05 level, the timing is significant in comorbidity, primary diagnosis; the outcomes are associated with the timing of stoma closure, comorbidity, patients¡¦ age and gender, hospital ownership and physician annual volume. Through this study, a perfect timing of stoma closure should be determined by the characteristics of patient and physician. Physicians could predict the timing through the stratified analysis and well organize the resource of hospital to improve the quality of medical care.

In case of a pandemic influenza outbreak, non-pharmaceutical interventions will likely be the only containment measure at the early stages of the pandemic when vaccines are not available. NPIs also oer an option for decreasing the probability of creating antiviral resistant viruses product of a mass prophylaxis campaign. In countries where there are not enough resources for vaccines and antivirals, NPIs may be the only mitigation actions available. NPIs have been increasingly used in preparedness plans. We can see recommendations and guidelines regarding the use of NPIs in countries, health departments and universities. Also, researchers all around the world have study the impact of NPI's in pandemic influenza outbreaks, most of them using simulation as their modeling tool. Our review of the aforementioned plans and literature shows that there is a lack of consensus in how to implement these interventions. They vary widely in the choice of key parameters such as intervention initiation threshold, duration and compliance. We believe that the lack of uniformity in NPI mitigation strategies arise from the uncertainty in the virus epidemiology and the current lack of scientic knowledge about the complex interactions between virus epidemiology with social behavioral factors and mitigation actions. In this dissertation we addressed this problem by modeling pandemic influenza outbreaks using an agent-based simulation approach. The model incorporates detailed popu- lation demographics and dynamics, variety of mixing groups and their contact processes, infection transmission process, and non-pharmaceutical interventions. Using a statistical experimental design approach we examine the influence of characteristic parameters of virus epidemiology, social behavior, and non-pharmaceutical interventions on various measures of pandemic impact such as total number of infections, deaths and contacts. The experimental design approach also yields the knowledge of the extent of interactions among the above parameters. Using this knowledge we develop eective NPI strategies and demonstrate the efficacy of these strategies on large-scale simulated outbreaks involving three dierent scenarios of virus transmissibility. The results show that signicant improvements in the NPI based pandemic mitigation approaches can be attained by the strategies derived from our methodology.

The work in this thesis is concerned with the mechanics of the initiation and growth of small fatigue cracks from notches under service load histories. Fatigue life estimates for components subjected to variable amplitude service loading are usually based on the same constant amplitude strain-life data used for constant amplitude fatigue life predictions. The resulting fatigue life estimates although they are accurate for constant amplitude fatigue, are always non conservative for variable amplitude load histories. Similarly fatigue life predictions based on small crack growth calculations for cracks growing from flaws in notches are non conservative when constant amplitude crack growth data are used. These non conservative predictions have, in both cases, been shown to be due to severe reductions in fatigue crack closure arising from large (overload or underload) cycles in a typical service load history. Smaller load cycles following a large near yield stress overload or underload cycle experience a much lower crack opening stress than that experienced by the same cycles in the reference constant amplitude fatigue tests used to produce design data. This reduced crack opening stress results in the crack remaining open for a larger fraction of the stress-strain cycle and thus an increase in the effective portion of the stress-strain cycle. The effective strain range is increased and the fatigue damage for the small cycles is greater than that calculated resulting in a non conservative fatigue life prediction. Previous work at Waterloo introduced parameters based on effective strain-life fatigue data and effective stress intensity versus crack growth rate data. Fatigue life calculations using these parameters combined with experimentally derived crack opening stress estimates give accurate fatigue life predictions for notched components subjected to variable amplitude service load histories. Information concerning steady state crack closure stresses, effective strain-life data, and effective stress intensity versus small crack growth rate data, are all obtained from relatively simple and inexpensive fatigue tests of smooth specimens in which periodic underloads are inserted into an otherwise constant amplitude load history. The data required to calibrate a variable amplitude fatigue crack closure model however, come from time consuming measurements of the return of crack closure levels for small cracks to a steady state level following an underload (large cracks for which crack closure measurements are easier to make cannot be used because at the high stress levels in notches under service loads a test specimen used would fracture). For low and moderately high hardness levels in metals crack growth and crack opening stress measurements have been made using a 900x optical microscope for the small crack length at which a test specimen can resist the high stress levels encountered when small cracks grow from notches. For very hard metals the crack sizes may be so small that the measurements must be made using a confocal scanning laser microscope. In this case the specimen must be removed from the test machine for each measurement and the time to acquire data is only practical for an extended research project. The parameters for the crack closure model relating to steady state crack closure levels vary with material cyclic deformation resistance which in turn increases with hardness. One previous investigation found that the steady state crack opening level was lower and the recovery to a steady state crack opening stress level after an underload was more rapid for a hard than for a soft metal. This observation can be explained by the dependence of the crack tip plastic zone size that determines crack tip deformation and closure level on metal hardness and yield strength. Further information regarding this hypothesis has been obtained in this thesis by testing three different steels of varying hardness levels (6 HRC, 35 HRC, and 60 HRC) including a very hard carburized steel having a hardness level (60 HRC) for which no crack opening stress data for small cracks had yet been obtained. This thesis introduced a new test procedure for obtaining data on the return of crack opening stress to a steady state level following an underload. Smooth specimens were tested under load histories with intermittent underload cycles. The frequency of occurrence of the underloads was varied and the changes in fatigue life observed. The changes in damage per block (the block consisted of an underload cycle followed by intermittent small cycles) were used to determine the value of the closure model parameter governing the recovery of the crack opening stress to its steady state level. Concurrent tests were carried out in which the crack opening stress recovery was measured directly on crack growth specimens using optical microscope measurements. These tests on metals ranging in hardness from soft to very hard were used to assess whether the new technique would produce good data for crack opening stress changes after underloads for all hardness levels. The results were also used to correlate crack closure model parameters with mechanical properties. This together with the steady state crack opening stress, effective strain-life data and the effective intensity versus crack growth rate data obtained from smooth specimen tests devised by previous researchers provided all the data required to calibrate the two models proposed in this investigation to perform strain-life and small crack growth fatigue analysis.

IT projects serve as the foundation through which a number of organizationalInformation Technology benefits can be created. However, it appears to be acomplicated task with great economic consequences at stake to finish a project beforepositive results can be reached. Project closure, the very last phase of the project lifecycle, seems to be underrepresented in current research compared to the other phasesof the project life cycle. The research regarding postponed closure, meaning thatprojects, which technically are finished, are still allowed to continue, or projects thatare directly unfeasible and therefore should be prematurely terminated, is even moreabsent. This indicates that problems arise somewhere, which is what will beinvestigated in this study.The aim of this study is to gain an understanding to the underlying reasons whycertain projects face a delayed closure, when they in reality should be finalizedearlier. In order to do so, a semi-structured interview study was carried out andpresented in a qualitative data analysis. The results of this study, based on empiricalfindings and support from theoretical frameworks, and presented in an analysis anddiscussion, indicates that there are a number of reasons that are causing postponedclosure. Among others, it has been noted that the planning for project closure maybegin too late in the process, that poor governance from the project manager and thesteering committee could be the result of hesitation to strict decision-making, and anunprepared receiving organization as a result of unsuccessful communication anddocumentation between internal and external stakeholders.

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Orthodontic closing loops offer an efficient way to control the moment to force ratios (M/F) delivered during space closure. The triangular loop is often used in the Graduate Orthodontic Clinic at the Indiana University School of Dentistry. Previous studies on the triangular loop were concerned with various loop geometries. The present project was designed to study the triangular loop in a clinically realistic experimental set up. Compared to the previous studies, three major changes were implemented: instead of two coplanar brackets, the current study employed a bracketed typodont arch (1) the effects of loop locations (2) and different interbracket distances were considered (3). The measured moment and forces reflect considerable differences in the systems due to the new experimental set up. As in previous studies, the triangular loops were fabricated from 0.016 X 0.022- inch stainless steel wire. The loops were equilateral triangles with 8 mm sides, ligated to the arch wire by elastomeric rings. There were 4 loop locations: location 1 was at 1.2 mm away from the mesial bracket; location 2 was at 3 .2 mm away from the distal bracket; location 3 was centered in the middle of the original interbracket distance; location 4 was located 2.6 mm away from the mesial bracket. There were three interbracket distances (IB). The original IB (IBl) of 12.6 mm was decreased by 3 mm (IB 2) and by 6 mm (IB 3). The loops were activated by 1.6 mm and 3.3 mm. Force and moment components were measured along three mutual perpendicular axes (x, y, and z) corresponding to the buccolingual, mesiodistal, occlusogingival axes respectively. Comparisons of Mx/Fy and Mz/Fy at the mesial and distal, by three activation levels, three interbracket distances, and four locations, and all interaction effects, were performed using a mixed design repeated measures ANOV A procedure. The General Linear Model (GLM) procedure for unbalanced designs was used because not all interbracket distances could be accommodated with all loop locations. Activation distance was the within specimen repeated factor. Loop location and interbracket distance were the between specimen factor. It was theorized that the location of the triangular loop, as well as the interbracket distance, have a considerable effect on the generated M/F. The Null Hypothesis was that there are no significant differences (p > 0.05) in the M/F ratios generated by the triangular loop as the loop position changes relative to the brackets, and there are no significant differences (p>0.05) in the M/F ratios generated by the triangular loop as the interbracket distance becomes shorter with space closure. Statistical significant interactions were found for Mx/Fy and Mz/Fy at location 2, for all activations, at both the mesial and distal measures. Therefore we rejected the first part of the Null Hypothesis (no differences as the loop location changes), and accept the second part (no differences as the interbracket distance shortens). We were able to see clear trends at all loop locations, as well as interbracket distances, and draw useful clinical implications. We found that the mesial closing forces are quite small when compared to those at the distal. We attributed this discrepancy to the U shape geometry of the continuous arch wire technique. We observed that if closing loops are delivered with no activation, then counterproductive M/F ratios are produced. Our data also indicated that anchorage becomes more critical as the interbracket distance shortens. Finally, we determined that wire tie ligation for prevention of rotation along the long axis of the tooth is especially important for the lateral incisor.

The Wnts, a family of secreted glycoprotein ligands, act through the frizzled (Fz) receptor, a family of seven-transmembrane (7TM) receptor proteins, to mediate intracellular signaling pathways that regulate cell fate determination, cell migration, or both. Whereas many molecular components of the Wnt signal transduction cascade have been identified, it remains unclear how the signal is transduced from the Fz receptors to the cytoplasm. To address this important question, a membrane-based yeast two-hybrid (MbY2H) screen was performed to identify potential Fz-interacting proteins. For this screen, the Frizzled7 (Fz7) protein was used as the bait and a mouse brain library was used the prey. This screen identified resistance to inhibitors of cholinesterase 8 homolog A (Ric8A), a 542–amino acid cytoplasmic protein, along with other proteins as putative Fz7-binding proteins. Ric8A had been studied previously in C. elegans and D. melanogaster for its function in regulating asymmetric cell division as a receptor-independent guanine nucleotide exchange factor (GEF) for Gα proteins. Additional studies in M. musculus and X. laevis further uncovered a role for this protein during gastrulation and neurulation; however, the mechanisms by which Ric8A regulated these processes remained unclear. In this thesis, I show Ric8A to be a bona fide binding partner for both Fz7; that Ric8A can also bind to the phosphoprotein Dishevelled (Dvl); and that both its interaction with Fz7 and Dvl is Wnt-regulated. The spatial and temporal mRNA expression pattern of the Xenopus homologue of Ric8A suggests a potential role in regulating Wnt signaling. The Xenopus homologue of Ric8A was cloned and gain-of-function and loss-of-function approaches in Xenopus uncovered a role for Ric8A in gastrulation and neural tube closure. Additionally, we found inhibition of Ric8A function mechanistically prevents activation of Rac1 which is required downstream of Wnt/Fz signaling during gastrulation. Overall, this study uncovers a novel regulator of Wnt signaling during early development / Biology