Multivariate Analysis Applied to the California Health Interview Survey

Objective: Identify if principle components analysis and multiple correspondence analysis are suitable dimension reduction techniques for the California Health Interview Survey. Identify which health risk behaviors, mental health and demographic factors cluster utilizing k-medians clustering. Background: Clustering and multivariate analysis techniques can be used to characterize populations and sub-populations of people by grouping them based on an individual’s similarity to others. These exploratory techniques, while uniformly accepted within the scientific community as valid, are not as popular as other statistical methods and have not been utilized in certain scenarios where they could potentially be useful. The UCLA Center for Health Policy Research’s annual California Health Interview Survey (CHIS) dataset is one such example where using these multivariate techniques could provide new insight. The survey contains information on thousands of randomly sampled Californians regarding health, income and demographics, among other factors. This research project attempts to determine if principle components analysis and multiple correspondence analysis are suitable dimension reduction techniques when applied to the CHIS dataset and to quantify and qualify in greater detail the differences and similarities between the health characteristics of California residents. Methods: This study used data from 21,055 individuals interviewed via telephone from the 2016 California Health Interview Survey, the largest state-wide health survey in the U.S. The statistical procedures principle components analysis and multiple correspondence analysis were conducted to assess their usefulness when applied to health survey data. Concurrently, Gower k-medians clustering was used to identify distinct groupings of California residents. I then performed a chi-squared test to determine which variables are the most statistically significant in forming these clusters. Results: Principle components analysis reduced the initial 118 variables considered to 30, with the largest component only explaining 10.44% of the total variation in the data, suggesting that this technique is ill-suited to the CHIS. Multiple correspondence analysis, however, reduced the 88 categorical variables to 5 with the largest component accounting for 62.27% of the variation in the data. By applying Gower k-medians, I produced 3 distinct clusters of survey respondents and determined that access to specialized medical care is the most strongly clustered characteristic

Nonlinear time-warping made simple: a step-by-step tutorial on underwater acoustic modal separation with a single hydrophone

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bonnel, J., Thode, A., Wright, D., & Chapman, R. Nonlinear time-warping made simple: a step-by-step tutorial on underwater acoustic modal separation with a single hydrophone. The Journal of the Acoustical Society of America, 147(3), (2020): 1897, doi:10.1121/10.0000937.Classical ocean acoustic experiments involve the use of synchronized arrays of sensors. However, the need to cover large areas and/or the use of small robotic platforms has evoked interest in single-hydrophone processing methods for localizing a source or characterizing the propagation environment. One such processing method is “warping,” a non-linear, physics-based signal processing tool dedicated to decomposing multipath features of low-frequency transient signals (frequency f  1 km). Since its introduction to the underwater acoustics community in 2010, warping has been adopted in the ocean acoustics literature, mostly as a pre-processing method for single receiver geoacoustic inversion. Warping also has potential applications in other specialties, including bioacoustics; however, the technique can be daunting to many potential users unfamiliar with its intricacies. Consequently, this tutorial article covers basic warping theory, presents simulation examples, and provides practical experimental strategies. Accompanying supplementary material provides matlab code and simulated and experimental datasets for easy implementation of warping on both impulsive and frequency-modulated signals from both biotic and man-made sources. This combined material should provide interested readers with user-friendly resources for implementing warping methods into their own research.This work was supported by the Office of Naval Research (Task Force Ocean, project N00014-19-1-2627) and by the North Pacific Research Board (project 1810). Original warping developments were supported by the French Delegation Generale de l'Armement

Non-Invasive Picosecond Pulse System for Electrostimulation

Picosecond pulsed electric fields have been shown to have stimulatory effects, such as calcium influx, activation of action potential, and membrane depolarization, on biological cells. Because the pulse duration is so short, it has been hypothesized that the pulses permeate a cell and can directly affect intracellular cell structures by bypassing the shielding of the membrane. This provides an opportunity for studying new biophysics. Furthermore, radiating picosecond pulses can be efficiently done by a compact antenna because the antenna size is comparable to the pulse width. However, all of the previous bioelectric studies regarding picosecond pulses have been conducted in vitro, using electrodes. There is not yet a device which can non-invasively deliver picosecond-pulsed electric fields to neurological tissue for therapeutic applications. It is unclear whether a radiated electric field at a given penetration depth can reach the threshold to cause biological effects. In this dissertation, a picosecond- pulsed electric field system designed for the electrosimulation of neural cells is presented. This begins with the design of an ultra-wideband biconical dielectric rod antenna. It consists of a dielectrically loaded V-conical launcher which feeds a cylindrical waveguide. The waveguide then transitions into a taper, which acts like a lens to focus the energy in the tissue target. To describe the antenna delivery of picosecond pulses to tissues, the initial performance was simulated using a 3-layer tissue model and then a human head model. The final model was shown to effectively deliver pulses of 11.5 V/m to the brain for a 1 V input. The spot size of the stimulation is on the order of 1 cm. The electric field was able to penetrate to a depth of 2 cm, which is equal to the pulse width of a 200 ps pulse. The antenna was constructed and characterized in free space in time domain and in frequency domain. The experimental results have a good agreement with the simulation. The ultimate biological application relies on adequate electric field. To reach a threshold electric field for effective stimulation, the antenna should be driven by a high voltage, picosecond-pulsed power supply, which, in our case, consists of a nanosecond charging transformer, a parallel-plate transmission line, and a picosecond discharging switch. This transformer was used to charge a parallel-plate transmission line, with the antenna as the load. To generate pulses with a rise time of hundreds of picoseconds, an oil switch with a millimeter gap was used. For the charging, a dual resonance pulse transformer was designed and constructed. The novel aspect of this transformer is has a fast charge time. It was shown to be capable of producing over 100 kV voltages in less than 100 ns. After the closing of the peaking switch and the picosecond rise time generation, the antenna was able to create an electric field of 600 V/cm in the air at a distance of 3 cm. This field was comparable to the simulation. Higher voltage operation was met with dielectric breakdown across the insulation layer that separates the high voltage side and the ground side. Before the designed antenna is used in vivo, it is critical to determine the biological effect of picosecond pulses. This is especially important if we focus on stimulatory effects, which require that the electric field intensity be close to the range that the antenna system can deliver. Toward that end, neural stem cells were chosen to study for the proliferation, metabolism, and gene expression. Instead of using the antenna, the electrodes were used to deliver the pulses to the cells. In order to treat enough cells for downstream analyses, the electrodes were mounted on a 3-D printer head, which could be moved freely and could be controlled accurately by programming. The results show that pulses on the order of 20 kV/cm affect the proliferation, metabolism, and gene expression of both neural and mesenchymal stem cells, without reducing viability. In general, we came to the conclusion that picosecond pulses can be a useful stimulus for a variety of applications, but the possibility of using antennas to directly stimulate tissue functions relies on the development of a pulsed power system, high voltage insulation, and antenna material

The Relationship Between Resource Allocation Patterns in Missouri K-12 Public School Districts and Student Performance

The link between school funding and student achievement has been a topic of debate for many years. School leaders and policy makers have sought ways to increase student achievement while using educational funding in an efficient manner. Previous initiatives to examine the relationship between funding and achievement have included education production functions, standards-based reforms, reallocation of resources, and minimum funding levels. This study was designed to examine the relationship between resource allocation patterns and student achievement in 447 Missouri K-12 public schools. The relationship between school districts¿ resources and their achievement on the 10th grade mathematics and 11th grade communication arts portions of the Missouri Assessment Program (MAP) test were analyzed using a multiple linear regression analysis. The initial results of the study showed no relationship between district level expenditures and student achievement. However, the second part of the study showed that a district¿s PEER group, average teachers¿ experience, student-teacher ratio, and percent of teachers with a Masters degree were related to student achievement. This information will be useful to school leaders and policy makers as they work to increase levels of achievement while operating on budgets of varying size. The third part of the study examined the relationship between student achievement and a proposed 65 percent minimum funding level for instruction related expenses. Despite the growing popularity that the 65 Percent Solution is receiving with education policy makers across the country, the results of this study do not provide evidence that meeting this expenditure level will result in high levels of achievement

The Folly of Reason and Gravity of Reconciled Humor in Horkheimer and Adorno’s Dialectic of Enlightenment

The aim of this paper is to show how, taken at face value, it appears that Horkheimer and Adorno’s conception of the culture industry presented in The Dialectic of Enlightenment does not allow for integral freedom--or the very freedom which is at the heart of modernity’s conception of the person and is the basis for its political philosophy.  Nevertheless, the text has the resources to support a slightly less pessimistic reading, and provide a role for irony which came to be among prevalent artistic practices for postmodern aesthetics. That is, once the distinction between terrible laughter and reconciled laughter as well as terrible and reconciled humor is understood, the text rewards rational reconstruction to demonstrate the folly of reason, and in doing so, we might experience The Dialectic of Enlightenment itself as an instance of reconciled humor. Perhaps, the text itself offers a way to mitigate against Horkheimer and Adorno’s condemnation of the culture industry so that it is less totalizing than it would first appear. Therefore, laughter has a critical role in a slightly less pessimistic reading of the text as once the distinction between reconciled and terrible laughter is integrated into the text itself, one may interpret the Dialectic of Enlightenment as an exercise in reconciled humor, and not the terrible humor so frequently found in the culture industry. The freedom involved in this beneficial sort of humor-- reconciled humor-- may be fleeting, but it is nevertheless significant

Professional Judgment and Emergency Fund Programs: An Opportunity to Improve

In Spring 2020, during the onset of the COVID-19 pandemic, the number of students facing financial hardships increased as job losses mounted and schools closed their campuses. Schools, the federal government, and other organizations stepped in to help students deal with emergencies; but there are often hurdles to quickly getting emergency aid into the hands of students. While Title IV of the Higher Education Act provides a viable response mechanism through its emergency aid provisions, these provisions are underutilized. In this paper, we discuss ways in which schools can more effectively use professional judgment authority to quickly get emergency aid to students when they need it. We also discuss ways in which Congress can improve federal policy by removing needless restrictions