AJUR Volume 16 Issue 3 (December 2019)

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AJUR Volume 16 Issue 3 (December 2019)


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

p.5. Women in Higher Educational Leadership: Representation, Career Progression, and Compensation
Carla Cañas, Caitlyn Keeve, Carmen Ramos, Jocelyn Rivera, & Michelle L. Samuel
Department of Psychology, Mount Saint Mary’s University, Los Angeles, CA
https://doi.org/10.33697/ajur.2019.026
ABSTRACT: Men in university administration repeatedly outnumber women in leadership positions. The problem under investigation is that this gender gap exists due to barriers to advancement and discrimination in both the hiring process and in the workplace. With less representation of women in higher education leadership, there is a higher risk of bias for women in this field. This study used an ex-post facto methodology and gathered public data from the University of California (UC) Annual Payroll Compensation database. Three separate studies were run to determine the level of gender differences in the representation of educational leaders, compensation, and career progression. Significant differences in gender equity existed, with more men represented at several levels of educational leadership. Significant differences were also found in compensation levels, where men earned more money than women in the same position. Lastly, a small effect, although not significant, was observed when comparing early career gender representation to non-early career gender representation. There are more women recent graduates than men in leadership positions. Together these results suggest that while there are gender gaps in representation and compensation, there may be slow progress towards better representation in early career leadership positions in the UC system. The implication of this research supports further research into factors which impact the compensation of women leaders in academia. Higher education hiring professionals and candidates for leadership positions could benefit from further development of theories around gender equity and representation.
KEYWORDS: Gender Representation; Gender Equity; Higher Educational Leadership; Women; Higher Education; Psychology; Wage Gap; Higher Education Administration

p.15 Anisotropic Behavior of Ultrasonic Waves in 3D Printed Materials
Edward Alexandera* & Gordon D. Hoopleb
aDepartment of Mechanical Engineering, Shiley-Marcos School of Engineering, University of San Diego, San Diego, CA
bDepartment of Integrated Engineering, Shiley-Marcos School of Engineering, University of San Diego, San Diego, CA
https://doi.org/10.33697/ajur.2019.027
ABSTRACT: This study quantifies the anisotropic behavior of ultrasonic wave transmission for materials printed with three different 3D printers. As 3D printed materials become more prevalent in manufactured products, fully characterizing the physical properties of these materials become more important. This paper examines the longitudinal velocity of sound and acoustic impedance in two directions: orthogonal and parallel to the printed layers. Each of the 3D printed materials displayed slightly different transmission results. For PMMA like samples printed on a SLA printer waves travelled more quickly in the orthogonal direction than the parallel direction. For samples printed on an industrial FDM printer using ABS the opposite was true: the parallel direction was faster than the orthogonal. For samples printed on an entry level FDM printer with PLA there was no consistent pattern, instead there was a tight clustering of ultrasonic velocity in the parallel direction but substantial variation in the orthogonal direction. Overall the variation between the orthogonal and parallel directions was found to be less than 2% in all cases.
KEYWORDS: 3D Printing; Additive Manufacturing; Ultrasonic Waves; Anisotropic Material Properties; ABS; PLA

p.23 Why Regimes Repress: The Factors that Lead to Censorship of Social Media
Ezhan Hasan
Department of Political Science, Texas Christian University, Fort Worth, TX
https://doi.org/10.33697/ajur.2019.028
ABSTRACT: Social media have made it easier to create mass political action. Prominent examples include the Arab Spring movements, which took place in regions where information was previously tightly controlled by authoritarian regimes. Fearing radical change, several regimes have repressed social media use, but not all authoritarian regimes have taken the same measures. Previous research suggests that regime leadership is motivated to ensure its own survival but also influenced by a strong independent media and the need for citizens to vent grievances. To understand the relationship of these factors to social media repression, this research conducts a comparative process-tracing case study of Iran, Turkey, and Venezuela from 2004 to 2017, using a hypothesis-testing approach. It concludes with discussion of the findings for the nature of regime response to the role of social media in protest.
KEYWORDS: Internet; Media; Protest; Authoritarian; Iran; Turkey; Venezuela; Comparative; Case-Study

p.43 Investigation of Constant Volume and Constant Flux Initial Conditions on Bidensity Particle-Laden Slurries on an Incline
Dominic Diaz*, Jessica Bojorquez, Joshua Crasto, Margaret Koulikova, Tameez Latib, Aviva Prins, Andrew Shapiro, Clover Ye, David Arnold, Claudia Falcon, Michael R. Lindstrom, & Andrea L. Bertozzi
Department of Mathematics, University of California, Los Angeles, CA
https://doi.org/10.33697/ajur.2019.029
ABSTRACT: Particle-laden slurries are pervasive in both natural and industrial settings, whenever particles are suspended or transported in a fluid. Previous literature has investigated the case of a single species of negatively buoyant particles suspended in a viscous fluid. On an incline, three distinct regimes emerge depending on the particle concentration and inclination angle: settled (where particles settle and there is a pure fluid front), well-mixed (where particle concentration is constant throughout), and ridged (where a particle-rich ridge leads the flow). Recently, the same three regimes were also found for constant volume two species bidensity slurries. We extend the literature on bidensity slurries by presenting results on constant volume and a new type of initial condition: constant flux, where slurry is pumped onto the incline at a constant rate. We present front positions of the slurries and compare them to theoretical predictions. In addition, height profiles (film thicknesses) are also presented for the constant flux case, showing the distinct behavior of the ridged regime. We find that for constant flux conditions the settled regime forms for small particle volume fractions and inclination angles while the ridged regime forms for large corresponding values. Intermediate values of these two parameters are shown to produce a well-mixed regime.
KEYWORDS: Thin Films; Particle-Laden Flow; Multiphase Fluids; Interfacial Flows; Particle Segregation

p.59 A Monte Carlo Simulation Study on the Power of Autocorrelation Tests for ARMA Models
Zachary Wenning* & Emily Valenci
Department of Statistics, Pennsylvania State University, University Park, PA
https://doi.org/10.33697/ajur.2019.030
ABSTRACT: It is often the case when assessing the goodness of fit for an ARMA time series model that a portmanteau test of the residuals is conducted to assess residual serial correlation of the fitted ARMA model. Of the many portmanteau tests available for this purpose, one of the most famous and widely used is a variant of the original Box-Pierce test, the Ljung-Box test. Despite the popularity of this test, however, there are several other more modern portmanteau tests available to assess residual serial autocorrelation of the fitted ARMA model. These include two portmanteau tests proposed by Monti and Peña and Rodríguez. This paper focuses on the results of a power analysis comparing these three different portmanteau tests against different fits of ARMA – derived time series, as well as the behavior of the three different test statistics examined when applied to a real-world data set. We confirm that for situations in which the moving average component of a fitted ARMA model is underestimated or when the sample size is small, the portmanteau test proposed by Monti is a viable alternative to the Ljung-Box test. We show new evidence that the Peña and Rodríguez may also be a viable option for testing for residual autocorrelation for data with small sample sizes.
KEYWORDS: Time Series; Monte Carlo; ARMA Models; Power; Simulation; Autocorrelation Tests; Portmanteau Tests; Monti; Ljung-Box; Peña and Rodríguez

p.69 Evaluating the Effects of Bisphenols F and S with Respect to Bisphenol A on Primordial Germ Cell Migration in Zebrafish (Danio rerio) Embryos Using Immunofluorescent Microscopy
Siti Sarah Safura*, George Roba, & Edward Freeman
Department of Biology, St. John Fisher College, NY
https://doi.org/10.33697/ajur.2019.031
ABSTRACT: Primordial Germ Cell (PGC) migration occurs in early embryonic development and is highly conserved across taxa. PGC migration occurs within the first 24 hours post fertilization (hpf) in zebrafish, making the organism an efficient model for observing the migration pathway. Proper PGC migration is necessary for normal gonad development and, in some species, sex determination. Disruption of this process leads to defects in gonad formation and abnormal sex determination and differentiation. Studies show that endocrine-disrupting chemicals such as bisphenol A (BPA) disrupt PGC migration in zebrafish. BPA is an estrogenic compound that has been linked to a variety of human diseases, including various cancers, diabetes, reproductive disorders, obesity, and cardiovascular diseases. It is one of the most widely used synthetic compounds worldwide, as it used to make polycarbonate plastics. Many studies provide evidence of the harmful effects of BPA on living organisms. In response, manufacturers have started to use replacements such as bisphenol F (BPF) and bisphenol S (BPS). However, due to their structural similarity, it is likely that BPF and BPS are just as harmful to organisms as BPA. In this study, we use antibody staining and immunofluorescence microscopy to confirm that BPA exposure results in abnormal PGC migration in zebrafish embryos, as previously studied, and to illustrate that BPF and BPS exposure results in similar PGC migration defects.
KEYWORDS: Zebrafish; Zebrafish Embryos; Primordial Germ Cells; PGC Migration; Gonad Development; Endocrine-Disrupting Chemicals; Bisphenol A; Bisphenol S; Bisphenol F; Sex Determination

p.79 Exposure and Loss of Environmental Enrichment Mediates Ethanol Consumption in Adolescent Female Rats
Natalie Lipari*a, Max Baronb, & Joshua A. Pecka
aPsychology Department, State University of New York at Cortland, Cortland, NY
bPsychology Department, University of Michigan, Ann Harbor, MI
https://doi.org/10.33697/ajur.2019.032
ABSTRACT: Alcohol use among adolescent females has significantly increased in the United States with young women drinking alcohol at the same rate as young men. One potential treatment strategy that could help sustain alcohol abstinence is Environmental Enrichment (EE). Environmental enrichment is a process concerning the stimulation of the brain by one’s physical and social surrounding, which promotes non-drug reinforcement alternatives (e.g. voluntary exercise) supporting drug abstinence. Thus, the primary focus of this study was to investigate the effect of EE on ethanol (ETOH) abstinence in adolescent female rats. All adolescent female rats, starting on postnatal day 30, had 24-h access to 2%, then 4%, and then 6% ethanol concentrations. At the end of the four weeks, the environmental conditions were switched (EE→NEE and NEE→EE) and the 6% ethanol measure was repeated. We found that EE significantly reduced ethanol consumption for adolescent female rats compared to controls. Further, the removal of EE opportunities resulted in a significant increase in ethanol consumption. Collectively, the results suggest that access to enriched life conditions are important in facilitating alcohol abstinence in adolescent female rats.
KEYWORDS: Adolescent Females; Alcohol Consumption; Environmental Enrichment; Alcohol Use Disorder; Treatment Strategy; Alcohol Abstinence; Ethanol; Adolescent Female Rats