AJUR Volume 16 Issue 2 (September 2019)

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Links to individual manuscripts, abstracts, and keywords are provided below.

Classifying Lensed Gravitational Waves in the Geometrical Optics Limit with Machine Learning
Amit Jit Singh, Ivan S.C. Li, Otto A. Hannuksela, Tjonnie G.F. Li, & Kyungmin Kim
https://doi.org/10.33697/ajur.2019.019
ABSTRACT: Gravitational waves are theorized to be gravitationally lensed when they propagate near massive objects. Such lensing effects cause potentially detectable repeated gravitational wave patterns in ground- and space-based gravitational wave detectors. These effects are difficult to discriminate when the lens is small and the repeated patterns superpose. Traditionally, matched filtering techniques are used to identify gravitational-wave signals, but we instead aim to utilize machine learning techniques to achieve this. In this work, we implement supervised machine learning classifiers (support vector machine, random forest, multi-layer perceptron) to discriminate such lensing patterns in gravitational wave data. We train classifiers with spectrograms of both lensed and unlensed waves using both point-mass and singular isothermal sphere lens models. As the result, classifiers return F₁ scores ranging from 0:852 to 0:996, with precisions from 0:917 to 0:992 and recalls ranging from 0:796 to 1:000 depending on the type of classifier and lensing model used. This supports the idea that machine learning classifiers are able to correctly determine lensed gravitational wave signals. This also suggests that in the future, machine learning classifiers may be used as a possible alternative to identify lensed gravitational wave events and to allow us to study gravitational wave sources and massive astronomical objects through further analysis.
KEYWORDS: Gravitational Waves; Gravitational Lensing; Geometrical Optics; Machine Learning; Classification; Support Vector Machine; Random Tree Forest; Multi-layer Perceptron

Cost, Quality, and Access of Healthcare in Piura, Peru
Julia B. Griffin & Elaina F. Osterbur
https://doi.org/10.33697/ajur.2019.020
ABSTRACT: The aim of the study is to investigate the patient perceptions on the cost, quality, and access of health care services in Piura, Peru. Although one of the largest cities in Peru, Piura has one of the lowest densities of health care workers in the country which greatly impacts the population’s ability to receive medical treatment. Lack of financial resources and health literacy, among other health disparities exist. Modeled after CAHPSâ Health Plan Adult Commercial Survey 5.0 and the Patient Satisfaction Survey, a forty-four question English and Spanish survey was created with questions to study healthcare variables. As a correlational study with convenience sampling, the survey was administered to both patients and medical providers in eight city health centers. Over a period of twelve days, 107 surveys were collected. After eliminating subjects who did not meet the study criteria, 92 patients and 13 medical providers were included in the study. Findings from medical providers are not reported because of the small sample size. The results of this study suggests that 32% of subjects do not have health insurance, 24% of subjects rated their healthcare received as average, 18% of participants rated their healthcare as the best possible on a scale of zero to ten, and 29% of subjects had to wait an average of seven days for access to healthcare services when care is urgent. The results of this analysis can be used to better understand the Peruvian healthcare system and educate the Piura community and the Parish Santísimo Sacramento as they continue to improve and expand their health care services.
KEYWORDS: Cost; Quality; Access; Healthcare; Piura; Peru; Satisfaction; Parroquia Santísimo Sacramento; EsSalud; SIS; MINSA
APPENDICES: AJUR_Vol_16_Issue_2_September_2019_p17_appendices

The Effectiveness of Debt Relief: Assessing the Influence of the HIPC Initiative and MDRI on Tanzania’s Health Sector
Fernando Lopez Oggier
https://doi.org/10.33697/ajur.2019.021
ABSTRACT: Debt relief initiatives have been part of the international development sphere since the early 1990s. With the launch of the Heavily Indebted Poor Country (HIPC) Initiative in 1996 and the Multilateral Debt Relief Initiative (MDRI) in 2005 many countries have been able to successfully qualify for debt relief. Tanzania has been one of the primary beneficiaries of debt relief over the years. While empirical evidence demonstrates that the country’s economic growth has been positively impacted by debt relief initiatives, other aspects of human development need to be analyzed to ensure a comprehensive assessment of the HIPC Initiative and the MDRI. This study compiles Tanzania’s health data into a composite indicator to perform a graphical analysis to compare the trends between health outcomes and external debt. The graphical analysis is contextualized through a qualitative analysis of political, economic and health financing literature from the Bank of Tanzania, UNICEF and USAID. The results indicate that there health outcomes improved throughout the whole study’s time period particularly after the HIPC Initiative. The health financing literature also points to increased development expenditure during this period. Nonetheless, the effects of debt relief seem to diminish in the long-term due to fluctuations in external donors and logistical barriers to budget execution. Tanzania also continues to face socio-economic and geographic disparities in health outcomes and funding. Some of the literature also states that the country’s weak system of checks and balances and the lack of robust institutions could cause opportunistic policy preferences that might not necessarily improve Tanzania’s health outcomes.
KEYWORDS: Child Mortality Rate; Debt Relief; External Debt; Heavily Indebted Poor Country Initiative; International Monetary Fund; Life Expectancy; Maternal Mortality Rate; Multilateral Debt Relief Initiative; Official Development Aid; Prevalence of Undernourishment

The Association of TAS1R2 to Dental and Cardiovascular Health
Joseph Keryakos, Annika van Oosbree, & Alyssa Marie Kiesow
https://doi.org/10.33697/ajur.2019.022
ABSTRACT: Despite brushing and/or flossing their teeth twice daily, many people are still susceptible to dental cavities and tooth decay. This research investigates the genetic and cardiovascular health behind this phenomenon. Two gene variants related to taste pathways, taste 1 receptor member 2 (TAS1R2) and taste 2 receptor member 38 (TAS2R38), were tested on the DNA of 20 students at Northern State University (10 males and 10 females). In concert with genetic screening, tooth impressions were taken of the participants’ upper and lower jaws along with salivary pH, heart rates, and blood pressures. Participants’ cavities and fillings were counted and their gums examined for inflammation. Results showed that seven out of 10 males and two out of 10 females had the gene variant (TAS1R2). Students with this gene variant had an average salivary pH of 5.22—significantly lower than the salivary pH for the other non-carrier students (p < 0.05). These students also had smaller-sized tooth enamel, with none showing a size greater than one millimeter (x̄ = 0.84 millimeters). Students not expressing the gene variant had fewer cavities than those expressing the TAS1R2 gene variant (i.e., one of the regions amplified). Four of the males and both of the females that carried the gene variant also showed signs of swollen gums, possibly contributing to heart disease in the future. Blood pressures and heart rates for the carriers were statistically significant (p < 0.05), showing higher pressures and faster rates compared to non-carriers; meanwhile, all of the non-carriers had normal pressures and rates. Further, body mass index was lower among individuals without the gene variant. The results this limited study indicate that the TAS1R2 gene variant may play a role in cavity development and impact (or indicate poor) cardiovascular health, highlighting the importance of understanding the role of gene variants with regard to risk of tooth decay and gum and heart disease.
KEYWORDS: Dental cavities; Tooth decay; Gum and heart disease; Taste pathway gene; Gene variant; Blood pressure; Heart rate; Salivary pH; Tooth enamel

Body Image and Self-Esteem in Female College Students of Healthy Weight and Excess Weight: The Mediating Role of Weight Stigma
Carlie Smith, Jennifer Becnel, & Amanda Williams
https://doi.org/10.33697/ajur.2019.025
ABSTRACT: Emerging adulthood is an important transition in which the development of lifelong behaviors emerge. Recent research suggests that women in college are particularly vulnerable to poor body image and low self-esteem. This is also a time of possible weight gain as individuals learn to eat and exercise on their own. These are important as body mass index (BMI) influences how women feel about themselves and how others view them. Thus, the purpose of the present study was to examine the associations between body image, self-esteem, and weight stigma among female college students of healthy weight and excess weight. Participants (n=124; 83% White) were recruited to take a short survey administered online through Facebook advertisements and snowball sampling. Results reveled poorer body image and more experiences with weight stigma among individuals with excess weight. Additionally, weight stigma fully mediated the relationship between BMI and self-esteem as well as BMI and body image. Results were consistent with previous research noting the stigma and stereotypes associated with excess weight. Future work should examine these relationships in more diverse groups to identify those at greatest risk for negative self-concept for intervention.
KEYWORDS: Weight; Weight Stigma; Self-Esteem; Body Image; College Students; Women

After Hurricanes Irma and Matthew: Living Shorelines Stabilize Sediments
Taryn Chaya, Jessica Veenstra, & Melissa Southwell
https://doi.org/10.33697/ajur.2019.024
ABSTRACT: Constructed intertidal oyster reefs, an example of a “living shoreline”, can protect against erosion and loss of habitat, but can they prevent erosion during high-energy storm events such as hurricanes? Oyster reefs were constructed in 2012 within the Guana Tolomato Matanzas National Estuarine Research Reserve in Northeast Florida to stabilize the shoreline sediment and prevent erosion of an archeological site. Sediment cores were collected behind constructed oyster reefs before and after hurricanes Matthew (2016) and Irma (2017) to study changes in sediment particle size due to these high-energy storms. Pre-hurricane data were collected in 2016 from three different constructed reefs, as well as three control sites where no reef was present. Pre-hurricane sediment profiles behind the constructed reefs consisted of finer sediments, ~36% silt and clay, in the surface ~10-12 cm, with decreasing silt and clay and increasing sand content as depth increased. This was different than the sediment from the control sites with ~4% silt and clay in all depths sampled. Like the sediment profiles before the high energy storms, the post-hurricane sediment data showed a clear layer of finer sediment ~10-12 cm over coarser sediment. Although they were high-energy storms, the storms did not appear to significantly affect the sediment behind the constructed oyster reefs. Sediment profiles remained consistent after these storms but may not remain undisturbed during the next storm without some intervention because the oyster reefs have been degrading.
KEYWORDS: Oyster Restoration; Living Shorelines; Hurricanes; Coastal Erosion; Sedimentation; Salt Marsh