Click on this link to download the full high-definition interactive pdf for AJUR Volume 20 Issue 3 (December 2023) or https://doi.org/10.33697/ajur.2023.091
Links to individual manuscripts, abstracts, and keywords are provided below.
Sabrina Waite, Ian Nelson, & Jamie Spinney
ABSTRACT: Sidewalks are an important part of public space, but they are becoming increasingly dangerous, especially at night. Therefore, it is important that sidewalks are adequately illuminated to meet the safety, comfort, and accessibility needs (i.e., provide high levels of pedestrian reassurance) to sidewalk users. The objective of this case study was to quantitatively measure and subsequently explore the spatial and statistical distributions of light intensities along the sidewalks that surround Southern Utah University in Cedar City, Utah. A secondary objective was to develop a set of “adequate lighting” guidelines (i.e., 5 to 10 lux) to help identify areas that could benefit from sidewalks lighting enhancements. A digital light meter was used to measure horizontal light intensity, in lux, at a systematic sample of 208 points along the sidewalks within the study area. Geographic coordinates were also collected for each sample observation to enable mapping and spatial analysis of the light intensity data. Results indicate 61% of the observations have lux values equal to zero (complete darkness), 13.4% met or exceeded the minimum guidelines, while 4.3% fell within the “adequate lighting” guidelines adopted by this case study. These results suggest that sidewalks are too dark in too many places to provide reassurance to sidewalk users in the study area. The mapping and spatial analysis results from this case study also provide information to support targeted visibility enhancements of sidewalks within the study area. KEY WORDS: Lighting; Optimum Illuminance; Luminometer; Sidewalks; Pedestrians; Safety; Security; Reassurance
Olivia Atkins, Samantha Lopez, Yizhe Ma,& Louis Roberts
ABSTRACT: Human skin aging is characterized by epidermal and dermal thinning, loss of elasticity, and wrinkles. Keratinocytes, the most common type of skin cell and fibroblasts, present in the cellular stroma beneath the skin’s surface, each play a role in aging. Using these cell types in in vitro research can reveal a deeper understanding of the dermatological function and cellular changes in aged skin. 3D cell culture techniques provide an opportunity to use these cell types in a model that can more accurately mimic human skin. Treatment of aging skin is of interest to both medical and consumer communities. Retinoic acid (RA) is a metabolite of vitamin A and retinol that assists in cell proliferation, differentiation, and immune functions. Over the counter (OTC) and prescription retinoids are common topical products used for anti-aging and acne treatments. This study seeks to determine the impact of topical retinoid creams on keratinocyte proliferation and morphology in 3D cell culture models of aged and unaged human skin. NIH-3T3 fibroblasts were embedded in a 3D collagen matrix of varying thickness, and HaCaT keratinocytes were seeded on top of the matrix at varying seeding densities to mimic aging and youthful skin. 0.1 µM 0.025% tretinoin and 0.1 µM 0.1% adapalene topical creams were prepared in culture medium and used to treat cells daily, on alternate days, or just once during a week-long period. AlamarBlue assays and microscopy showed that tretinoin treatment was cytotoxic at this concentration, with a single treatment reducing cell viability by ~43% compared to the untreated control. Adapalene treatment, while showing significantly greater cell proliferation than tretinoin, did not exceed the proliferation of the untreated control. It is understood that retinol increases cell turnover by killing cells rapidly, so it is proposed that in our model, the rate of proliferation does not overcome the rate of cell death. Cell viability trends remain similar between young and old skin model treatments. Future studies should focus on creating a 3D model more accurately representing the aging in vivo skin environment where keratinocytes can be readily differentiated from epidermal stem cells. KEYWORDS: HaCaTs; NIH-3T3; Retinoids; Retinoic Acid; Tretinoin; Adapalene; 3D Collagen Gel; Proliferation
ABSTRACT: Guaranteed admission programs are a type of college access program that provide students who meet certain criteria (e.g., a minimum GPA) with guaranteed admission to one or more colleges. This paper studies guaranteed admission agreements between California State University San Marcos (CSUSM) and its local school district to evaluate if smaller scale, local guaranteed admission programs have comparable impacts on college enrollment rates to previously studied state-wide programs. Employing a regression discontinuity (RD) design around the program’s GPA cutoff conditional on students satisfying other program requirements, this paper finds that the program significantly increased enrollment at CSUSM and at any California State University (CSU) and increased (not significantly) the likelihood of students enrolling at four-year institutions compared to two-year alternatives. In addition, the program disproportionally affected students from underrepresented backgrounds (e.g., first-generation, nonwhite, and low-income backgrounds), suggesting that local guaranteed admission programs also have the potential to increase representation at four-year public institutions and encourage underrepresented students to enroll at higher-quality postsecondary institutions. KEYWORDS: Guaranteed Admission; College Enrollment; College Admissions; College Access; Higher Education; California State University; Education Policy; Local Policy
Chloe M. Sachs
ABSTRACT: Abortion in South Africa is a complex topic, rife with augmenting and limiting political, social, religious, and cultural factors. This study explores multiple age groups within Cato Manor and whether the attitudes towards abortion and factors impacting the choice of where and whether to receive an abortion differ. The study employs a general qualitative approach with inserted narratives highlighting individual perspectives and stories. The sample cohort was identified using purposive sampling of women, obtained via convenience through the gatekeeper in the community. The participants are from two generations, and two expert interviews were conducted to gain various perspectives. The sample population is from the greater Cato Manor community, and the interviews were conducted in a semi-structured format. The main goal of this study is to understand how socio-cultural factors impact abortion attitudes within each generation in Cato Manor and if community attitudes impact women’s decisions on how and where to obtain medical abortions. The findings show that negative attitudes towards abortion persist in Cato Manor due to religious and cultural rationale. Greater acceptance occurs among younger generations following abortion legalization in South Africa, yet prejudice remains. The research reveals a range of factors that may pressure women to obtain illegal abortion options to avoid community shame. KEYWORDS: Abortion; Pregnancy Termination; South Africa; KwaZulu-Natal; Cato Manor; Backstreet Abortions; Abortion Attitudes; Illegal Abortion
Suryadyuti Baral & Patrick J. Curran
ABSTRACT: Dynamic Structural Equation Model (DSEM) is a powerful statistical modeling approach that has recently gained popularity among researchers studying intensive longitudinal data. Despite its exciting potential, the stability and replicability of DSEM is yet to be closely examined. This study empirically investigates DSEM using recently published data to explore its strengths and potential limitations. The results show that while some of its parameter estimates are stable, others are characterized by substantial variation as a function of seemingly innocuous initial model estimation conditions. Indeed, some parameters fluctuate between significance and non-significance for the same model estimated using the same data. The instability of DSEM estimates poses a serious threat to the internal and external validity of conclusions drawn from its analyses, challenging the reproducibility of findings from applied research. Given the recent focus on the replication crisis in psychology, it is critical to address these issues as the popularity of DSEM in psychological research continues to rise. Several potential solutions are investigated to address this problem and recommendations of best practice are offered to applied researchers who plan to use DSEM in intensive longitudinal data analysis. KEYWORDS: Dynamic Structural Equation Model; Bayesian; Robust Estimation; Intensive Longitudinal Data
ABSTRACT: The graph invariant, aptly named the fixing number, is the smallest number of vertices that, when fixed, eliminate all non-trivial automorphisms (or symmetries) of a graph. Although many graphs have established fixing numbers, Johnson graphs, a family of graphs related to the graph isomorphism problem, have only partially classified fixing numbers. By examining specific orbit sizes of the automorphism group of Johnson graphs and classifying the subsequent remaining subgroups of the automorphism group after iteratively fixing vertices, we provide exact minimal sequences of fixed vertices, in turn establishing the fixing number of infinitely many Johnson graphs. KEYWORDS: Graph Automorphism Groups; Symmetry Breaking; Fixing Number; Determining Number; Johnson Graphs; Kneser Graphs; Graph Invariants; Permutation Groups; Minimal Sized Bases.
Gabriella Snetkov, Anna E. Youngkin, Megan E. Lui, Analia Marzoratti, &Tanya M. Evans
ABSTRACT: Anxiety can come in various forms; general anxiety is characterized by feelings of excessive anxiety impacting multiple domains of everyday life, whereas anxiety may also manifest within a single domain (i.e., math anxiety). Those that present with anxiety who also have Autism Spectrum Disorder often exhibit ritualized movement as a coping mechanism for their anxiety. However, the relationship between anxiety and movement has not yet been explored within typically developing children. It is also unclear if the form of anxiety impacts the degree to which children move. In this study, we used Motion Energy Analysis to quantify the relationship between both general and math anxiety and movement during a math flashcards task. Multivariate linear regression analysis was used to determine possible relationships between anxiety and movement. General anxiety significantly contributed to models predicting movement during the math flashcards task, while math anxiety did not. Our results suggest that movement could be an indicator of general anxiety in elementary aged children. KEYWORDS: General Anxiety; Math Anxiety; Elementary; Academics; Motion Energy Analysis; Movement; Ritualized Movement; Mathematics
Emily C. Montgomery, Nidhi Gupta, Matthew Atwill, Joel D. Bumgardner, & J. Amber Jennings
ABSTRACT: Titanium is a component of many implants and orthopedic instruments, such as screws and rods; however, this and other materials may serve as a nidus for bacterial biofilm attachment. Chitosan is a biopolymer with advantages as a surface modifier, and silver ions have broad-spectrum antimicrobial properties. For this study, chitosan is bound to silver through a novel, patented process. The purpose of this research is to characterize silane-linked chitosan-silver coatings for titanium, including comparing antimicrobial efficacy. In this study, silane-linked chitosan-silver titanium coupons reduced Staphylococcus aureus (S. aureus) viability by 98% (planktonic) and 99.5% (biofilm) while supporting viability of Saos-2 osteoblast cells at levels of 75% compared with control uncoated titanium. Due to the observation of retaining osteoblast viability while reducing bacterial viability, silane-linked chitosan-silver coatings could be useful for titanium implants to reduce post-operative infection as well as support the healing process.
KEYWORDS: Titanium; Staphylococcus aureus; Silver; Chitosan; Silane; Osteoblast; Antimicrobial; Coating