Comparison of Wechsler Memory Scale–Fourth Edition (WMS–IV) and Third Edition (WMS–III) dimensional structures: Improved ability to evaluate auditory and visual constructs

Dimensional structures underlying the Wechsler Memory Scale–Fourth Edition (WMS–IV) and Wechsler Memory Scale–Third Edition (WMS–III) were compared to determine whether the revised measure has a more coherent and clinically relevant factor structure. Principal component analyses were conducted in normative samples reported in the respective technical manuals. Empirically supported procedures guided retention of dimensions. An invariant two-dimensional WMS–IV structure reflecting constructs of auditory learning/memory and visual attention/memory (C1 = .97; C2 = .96) is more theoretically coherent than the replicable, heterogeneous WMS–III dimension (C1 = .97). This research suggests that the WMS–IV may have greater utility in identifying lateralized memory dysfunction

The referendum lighthouse: how state-level initiatives drive voter turnout

Indiana University-Purdue University Indianapolis (IUPUI)This thesis examines the use of ballot initiatives at the state level to determine whether the presence of certain types of ballot initiatives cause an increase in voter turnout at the state level. This study is unique in that rather than focusing on individual level voting behavior to explain why an individual may or may not be more likely to vote with the inclusion of ballot initiatives, I focus on aggregate level data to answer the following questions: do certain types of ballot initiatives have an effect on voter turnout? If so, how large is the effect? Collecting data from all ballot initiatives that appeared in the United States from 1998-2014, my research disputes the conventional wisdom that ballot initiatives have any effect on voter turnout during a presidential election. However, my research shows a four percent increase in turnout when any initiative appears on the ballot and a nearly five percent increase in voter turnout when an initiative concerning same-sex marriage appeared on the ballot during a non-presidential year election

Effects of Component Model Fidelity Level on Dynamic Analysis Accuracy of a Multi-MW Wind Turbine Drivetrain

Wind farms can incur major expenses due to turbine gearbox component failure that often occurs within five years of deployment. Turbine testing facilities such as Energy Innovation Center (EIC) in Charleston, SC are a growing resource used by the wind energy industry to improve our understanding of turbines in the field and accelerate turbine development. In the meantime, a multibody dynamics model has been developed in EIC for a mutli-MW wind turbine to carry out performance and life assessments to understand the influence of high-frequency mass and misalignment imbalance forces and gear transmission forces. This thesis aims to investigate multibody dynamics modeling options and understand how modeling fidelity level of four components of interest influences the simulated response of the entire drivetrain under load. The components of interest were the main shaft, bed plate, first planetary carrier, and gearbox housing. The model fidelity levels of these bodies were varied from flexible body representations containing many component modes to rigid body representation with few degrees of freedom. The system was subjected to ramped unidirectional loading input at the nose of the rotor hub, which emulates testing conditions that are periodically run on drivetrains at EIC. Campbell analysis was then performed on a subsystem gearbox model to understand how component flexibility affects the speed-dependent vibration of gearbox components. Activating more component modes was found to improve the relative accuracy in the motion of the high-speed shaft. This benefit was judged against the relative computational cost for activating each of the components\u27 modes. The bedplate\u27s dynamic modes had the greatest influence on the motion of the high-speed shaft. Representing all drivetrain bodies as rigid bodies leads to a significant overprediction of the internal motion and forces of the drivetrain. Activating the four components\u27 first thirty dynamic modes caused a computational cost increase of 5 times. Carrier and gearbox housing flexibility softens the vibration frequencies of the gearbox subsystem across the turbine operating speed range. Strategic recommendations are contributed according to some differing purposes in design and testing of turbine drivetrains

Partial Differential Equations

This paper will discuss methods for solving many different partial differential equations, as well as real world applications in physics. We are interested in finding solutions to the wave and heat equations in one dimension, the wave equation in two dimensions, as well as a solution to Schrodinger’s equation. In order to do this, we will study different methods including Fourier series, Bessel functions, and Hermite polynomials. I will use these methods to derive solutions for the mentioned problems, as well as to produce visualizations for many of them

The contribution of executive dysfunction to memory impairment and confabulation in schizophrenia

Study 1. Using a cognitive-process approach, 25 schizophrenic patients were matched with 25 healthy volunteers and compared on tests of memory and executive function. The schizophrenia group was found to have a significant impairment in immediate memory with relatively spared long-delay and recognition memory. Memory deficits were irrespective of the encoding strategies used and were unrelated to chronicity. In addition, the schizophrenic patients performed worse than controls on tests of executive function which was supported by some significant correlations between aspects of memory and executive function. The pattern of performance resembled that found in patients with subcortical or frontal lesions. Study 2. To examine further executive aspects of memory, an attempt to demonstrate confabulation in schizophrenia was made. Twelve schizophrenic patients were matched with 12 volunteers, 8 of whom were normal healthy subjects, with the remained being depressed patients. The subjects were asked to recall a set of experimental narratives, with confabulation being defined as the recall of ideas not present in the narrative. Subjects were also examined on a number of neuropsychological tests and the patients were assessed on the Krawiecka scale. Variable amounts of confabulation were observed in all the schizophrenic patients while only one control subject confabulated. The form of confabulation differed from those observed in other patients in that the original ideas were spontaneously rearranged to produce new ones. Confabulation was found to be related to difficulties in suppressing inappropriate responses and formal thought disorder. Study 3. Three schizophrenic patients previously identified as confabulators, were intensively studied to establish the mechanisms of narrative confabulation in schizophrenia. Patients were administered experimental tasks as well as standard neuropsychological tests of memory and executive function. Assessment of current symptoms was made using the SANS and SAPS scales. The severity of cognitive impairment was found to reflect the severity of confabulation, but memory impairment was neither nor sufficient to account for confabulation. Within the spectrum of executive deficits, impairments in response suppression and response monitoring, but not planning or generation were consistently associated with confabulation. The findings from the experimental tasks suggest that faults occur at both input and output. At the input stage, narrative material is encoded in a disorganised manner while at the output stage, this disorganisation is compounded by faulty editing processes. Study 4. Four schizophrenic patients who were known confabulators with narrative material, were subjected to an experimental autobiographical questionnaire designed to establish whether schizophrenic patients confabulate in response to questions calling on the recollection of personal facts and events. In addition, a number of neuropsychological tests were administered and current symptoms was assessed with the SANS and SAPS scales. All patients were observed to confabulate to varying degrees, particularly in response to questions relating to personal episodes rather than facts. For two patients, personal delusional systems were found to play a role in confabulation by providing a framework on which to base certain confabulatory recollections. Memory impairment was not found to be a necessary component to autobiographical confabulation but deficits in response suppression and response monitoring were observed to be related to the verification process performed during this task. Study 5. In an attempt to establish which anatomical regions may be at fault in schizophrenia when patients are engaged in response suppression tasks, six normal subjects were studied using positron emission tomography (PET) to identify anatomical regions involved when performing the Hayling Test. Subjects were also required to perform a control condition in which they had to read out the last word of given sentences. Compared to the control task, response initiation was associated with left sided activation of the frontal operculum, inferior frontal gyrus, middle temporal gyrus and right anterior cingulate gyrus, whereas response suppression was associated with left frontal operculum, inferior frontal gyrus and right anterior cingulate gyrus activation only. The difference between the two parts of the Hayling Test was in the increased activation of the left middle temporal gyrus and the left inferior frontal region (Brodmann's area 44/6) during response initiation

Development of hybrid composite bipolar plates for proton exchange membrane fuel cells

Bipolar plates are one of the most expensive components of a PEM fuel cell and by far the heaviest. Bipolar plates are responsible for providing flow fields for reaction gases, acting as current collectors for electrons liberated during the chemical reaction inside the cell, and providing structural support for the fuel cell stack. Current PEM fuel cell bipolar plate technology is built on the use of sintered graphite which is costly and requires time-consuming machining. Furthermore, due to the brittle nature of graphite, plates must be made relatively thick which adds significant weight and volume to larger stacks, such as those required for automobiles. Hybrid composite bipolar plates were developed with the goal of providing an alternative material which offers sufficient conductivity, corrosion resistance, and mechanical strength. A conductive resin system using epoxy, polyaniline, carbon black, and milled carbon fibers was developed to serve as a matrix for continuous carbon fiber reinforcement which enhanced both strength and conductivity above what is possible to achieve through the use of chopped fibers. The developed conductive resin system showed a high glass transition temperature (above 180⁰C) and tensile strength greater than or equal to 41 MPa. The developed hybrid composite material showed conductivity greater than 100 S/cm and excellent tensile and flexural strength, far exceeding industry targets --Abstract, page iii

An Examination of Predictors of Variance in the Caloric Content of Specific Bites of Food

Obesity continues to be a leading health risk throughout the world, and there is a need for tools to assess free-living eating behavior for both researchers attempting to study how specific eating behaviors contribute to obesity outside the lab and for individuals to use as self-monitoring aids. This study sought to examine how variance in individual traits and eating behaviors can be used to understand and predict the kilocaloric content of specific bites of food (KPB). It was hypothesized that meal duration, pre-meal satiety, food enjoyment, eating rate, age, gender, mouth volume, and body metrics would significantly predict KPB. Seventy-two participants were asked to eat two meals, consisting of three food items each. Participants were randomly assigned to two of five possible meals, never eating the same meal twice. Multi-level linear modelling was used to examine predictors of KPB: time in meal, time since last bite, food item enjoyment, pre-meal satiety, BMI, body fat percentage, waist-to-hip ratio, gender, mouth volume, and age. Additionally, the following mediation effects were hypothesized: the effect of time in meal would be mediated by time since last bite, satiety would be mediated by food item enjoyment, and the three body metrics would be mediated by food item enjoyment. Food enjoyment, pre-meal satiety, time in meal, and eating rate surfaced as the strongest predictors of KPB. The effect of time in meal on KPB appears to be partially mediated by time since last bite. However, there is no evidence that the effect of satiety is mediated by food item enjoyment. Additionally, a train-and-test analysis for model validation was performed, with one of each participant\u27s meals being used to train the model and the other used to test the model. The resulting model was found to perform better than previously derived models of KPB. While this study offers some new insight into predictors of KPB, additional work will be necessary before an accurate and applicable model of KPB can be derived from easily measured variables