Physical Sciences and Mathematics Commons^™

Selecting Without Replacement From A Population Of Bands Of Serially Connected Objects, James E. Marengo, Dominick Banasik, Joseph Voelkel, David L. Farnsworth

Articles

The sampling procedure from a finite population of objects that are serially attached into bands is described and analyzed. One object is randomly selected and removed at a time, which results in that object’s band being broken into two bands or shortened by one object. The main result gives the probability of choosing an object that is part of a band of serially connected objects of any specified size at each stage of the selection process.

Does Genetic Testing Influence Outcomes: Early Experience In Melanoma Case Series, Ryan Reyes, George Skenteris, Stella Coker Watson Self Ph.D., Ms, Christine Marie-Gilligan Schammel, Steven D. Trocha

Faculty Publications

Background:

The treatment and prognosis of melanoma have historically been based on histologic stage and Breslow depth; however, due to the increase in surveillance, melanomas are being identified at an earlier stage and lower Breslow depth. Advances in genetic testing, such as Decision Dx®, mean that melanoma diagnostic decisions and prognosis can now be directed by genetics. The purpose of this project was to assess the influence of a Decision Dx® high-grade (Class 2A/B) classification on the treatment of melanoma patients at a regional medical center, particularly those not deemed high risk by conventional classification methods, including Breslow depth and …

Empirical Comparisons Of Partial Dimension Reduction Algorithms In High-Dimensional Regression, Nathan Greenfield

Master's Theses

In high-dimensional regression problems, dimension reduction methods are often used to address the challenges of multicollinearity and estimation instability. Partial dimension reduction extends these ideas by applying dimension reduction to a subset of the predictors, while the remaining predictors are modeled without compression. This approach is particularly useful when it is important to retain variability and interpretability in certain predictors.

This thesis investigates the empirical performance of partial dimension reduction algorithms and introduces a novel algorithm, Iterative Partial Residual (IPR). Two algorithms are considered: a baseline algorithm, Marginal Residual (MR), and the proposed IPR method. Their predictive performance is evaluated …

Urban–Rural Disparities In Metabolic Risk Factors For Hypertension Among The Elderly In Indonesia, Susiana Nugraha, Puri Wulandari

Kesmas

Hypertension remains a major public health challenge among the elderly in low- and middle-income countries. This cross-sectional study examined demographic and metabolic factors associated with hypertension among the elderly living in urban and rural areas of West and Central Java Provinces, Indonesia. This study included 1,920 adults aged ≥60 years who had resided in the study areas for at least six months, were able to communicate effectively, and provided informed consent. Data were collected between March and August 2023 using stratified multistage random sampling, structured questionnaires, and biochemical measurements. Multivariable logistic regression revealed distinct patterns of association across settings. In …

Factors Associated With Antiretroviral Therapy Adherence In Patients With Hiv At A Public Hospital In Central Jakarta, Indonesia, Kareena Sari Fatimah, Laily Hanifah, Chandrayani Simanjorang, Nayla Kamilia Fithri

Kesmas

Patients with human immunodeficiency virus (HIV) are required to take antiretroviral therapy (ART) to suppress the virus. However, suboptimal adherence remains a critical barrier that can lead to treatment failure and persistent transmission risks. This study aimed to identify factors associated with ART adherence in patients with HIV. This quantitative study with a cross-sectional design consisted of patients with HIV aged >18 years who received care at the voluntary counseling and testing clinic of a public hospital in Jakarta, Indonesia. Purposive sampling was used. This study used HIV care and ART overview forms as instruments. Data were analyzed using multiple …

Association Between Dietary Folate And Prostate Cancer Aggressiveness Among African Americans And European Americans, Lihchyun Joseph Su, Sarah O'Connor, Daniela Ramirez Aguilar, Minjae Lee, Harrison Wong, Hui-Yi Lin, Jeannette T. Bensen, James L. Mohler, Lenore Arab, Longgang Zhao, Ebonee N. Butler, Laura Farnan, Susan E. Steck Phd, Mph, Rd

Faculty Publications

Background: Despite the confirmed beneficial effects on preventing neural tube defects, concerns about high intakes of synthetic folate, or folic acid, in promoting cancer progression have been raised. This study evaluated the association between folate intake and prostate cancer (PCa) aggressiveness among African-American (AA) and European-American (EA) males. Methods: This study included 722 AA and 775 EA men with prostate cancer. Folate intake (dietary folate equivalent (DFE), synthetic folate, natural folate) was estimated using the National Cancer Institute Dietary History Questionnaire and detailed dietary supplement use questionnaire. Analyses included univariable comparisons of demographic and clinical characteristics of the two racial …

Trends In Self-Reported Responses To Nutrition Facts Labels Before And After Nutrition Labeling Policy Implementation: A Comparison Of Adults In The United States And Mexico, Jim Thrasher Ph.D., Ma, Ms, Victor Vilalobos, Dai Fang, Alejandra Jáuregui, Alejandra Contreras-Manzano, Rachel Davis Ph.D., Lana Vanderlee, Christine M. White, Rachel B. Acton, James W. Hardin, Edward A. Frongillo Jr. Ph.D., Simón Barquera, David Hammond

Faculty Publications

Background

Objectives

Methods

A Transcriptional Program Associated With Neurotransmission In The Living Human Brain, Alexander W. Charney, Lora E. Liharska, Eric Vornholt, Alissa Valentine, Anina Lund, Alice Hashemi, Ryan C. Thompson, Terry Lohrenz, Jessica S. Johnson, Nicole Bussola, Esther Cheng, You Jeong Park, Salman Qasim, Alisha Aristel, Lillian Wilkins, Kimia Ziafat, Hannah Silk, Lisa M. Linares, Brendan Sullivan, Claudia Feng, Beniamino Hadj-Amar Ph.D.

Faculty Publications

At the foundation of neurotransmission, and by extension at the foundation of brain function, are coordinated programs of gene expression involving many thousands of genes. These programs are poorly defined in humans because most modern studies that characterize human brain gene expression use tissue obtained in the postmortem state when neurotransmission and brain function have ceased. Here, to advance knowledge of the gene expression programs at the foundation of neurotransmission in the human brain, gene expression was characterized in 130 prefrontal cortex (PFC) samples obtained from participants of the Living Brain Project (LBP) during neurosurgical procedures in conjunction with intracranial …

Survival On Image Regression With Application To Partially Functional Distributional Representation Of Physical Activity, Rahul Ghosal, Sunwoo Emma Cho, Marcos Matabuena

Faculty Publications

Technological advancements in wearable devices and medical imaging often lead to high-dimensional physiological signals in the form of images or surfaces. To address these data structures, we develop a novel survival on image regression model with a specific focus on partially functional distributional representation of wearable data. The existing approaches for functional data and survival outcomes have been primarily developed for uni-dimensional functional predictors. Drawing on recent developments in distributional data analysis, we model temporally varying distributional patterns of physical activity (PA) as a partially functional distributional predictor within a semiparametric Cox model framework. We use tensor product splines to …

Environmental Chemicals And Maternal Depression During And After Pregnancy: A Scoping Review, Pengfei Guo, Yunyue Shi, Cindy Nguyen, Haoran Zhuo, Tormod Rogne, Zeyan Liew

Faculty Publications

Purpose of Review

There is increasing evidence that several environmental exposures may pose a risk for depression, including maternal depression. We conducted a scoping review of epidemiological evidence regarding maternal exposure to environmental chemicals and perinatal depression.

Recent Findings

We searched PubMed, Embase, Web of Science, Dimensions, and Scopus, and summarized the findings from 27 articles that examined environmental chemical exposures and maternal depression. Studies of ambient air pollutants (N = 11) showed exposure to NO₂ and PM10 to be most consistently associated with antenatal or postnatal depression. Studies of endocrine-disrupting chemicals, including phthalates (n = 6), …

Project G.L.E.N. (Enhancing Tornado Research: A Foundation For Transistioning The Enhanced Fujita Scale), Alexis Peshehonoff, Makaylei Huggins, Bernard Muich, Nicholas Fazzolari, Liam John, Harris Meyer, Jakob Graudons, Nicholas Krasznavolgyi, Stephen Syvertson, Aditya Bhattacharya, Kai Hong, Augustine Balish, Zachary Ort, Erin Rhoden

Student Research Symposium (SRS)

"Project G.L.E.N., formally known as “Enhancing Tornado Research: A Case for Transitioning the Enhanced Fujita Scale,” is an ongoing initiative aimed at advancing tornado research through the development and deployment of an unmanned tornado probe. Through the Gale Level Environmental Navigator (G.L.E.N.) probe, a remote-controlled unit equipped with specialized meteorological sensors and innovative design features, we aim to collect real-time, onsite data from within tornadoes. This approach allows for direct measurement of internal atmospheric conditions such as wind speeds, pressure fluctuations, temperature, humidity, and other storm dynamics while removing human risk from tornado interception, significantly enhancing the safety of storm …

A Mechanistic Model Of The Wash Shuffle And Monte Carlo Exploration Of Its Impact On Card Shuffling In Texas Hold’Em, Michael A. Alexeev, Peter B. Chi

UNLV Gaming Research & Review Journal

In casino games using a standard deck of cards, a wash shuffle is sometimes performed prior to the rest of the card shuffling procedure. Unlike other methods of shuffling, the wash shuffle has not yet been well studied. To this end, we first develop a mechanistic model of the wash shuffle based on our observation of how cards tend to move when a wash shuffle is being performed. Then, we use this model to simulate the card shuffling procedure used in casino poker rooms, and explore the resulting impact on where the cards are dealt in the context of Texas …

Effective Wordle Heuristics, Ronald I. Greenberg

Computer Science: Faculty Publications and Other Works

While previous researchers have performed an exhaustive search to determine an optimal Wordle strategy, that computation is very time consuming and produced a strategy using words that are unfamiliar to most people. With Wordle solutions being gradually eliminated (with a new puzzle each day and no reuse), an improved strategy could be generated each day, but the computation time makes a daily exhaustive search impractical. This paper shows that simple heuristics allow for fast generation of effective strategies and that little is lost by guessing only words that are possible solution words rather than more obscure words.

Tidychangepoint: A Unified Framework For Analyzing Changepoint Detection In Univariate Time Series, Ben Baumer, Biviana Marcela Suárez Sierra

Statistical and Data Sciences: Faculty Publications

We present tidychangepoint, a new R package for changepoint detection analysis. Most R packages for segmenting univariate time series focus on providing one or two algorithms for changepoint detection that work with a small set of models and penalized objective functions, and all of them return a custom, nonstandard object type. This makes comparing results across various algorithms, models, and penalized objective functions unnecessarily difficult. tidychangepoint solves this problem by wrapping functions from a variety of existing packages and storing the results in a common S3 class called tidycpt. The package then provides functionality for easily extracting comparable numeric or …

Ecologic Factors Contributing To West Nile Virus Hyperendemicity In Central South Carolina: An Integrated Vector–Human–Environmental Study, Elba S. Fridriksson, Ahayla Muraleedharan, Kyndall C. Dye-Braumuller, Madeleine M. Meyer, Kia Zellars, Hiuxuan Li, Melissa S. Nolan Ph.D., Mph

Faculty Publications

West Nile virus (WNV) is an endemic arboviral infection in the United States that has undergone phyloge-netic evolution since its introduction 25 years ago. An integrated vector–human–pathogen study was conducted in the summer of 2023 to unearth contemporary Culex quinquefasciatus habitat patterns and human transmission spillover foci in South Carolina, a state with historically little WNV data. A serosurvey revealed WNV seroprevalence 10 times the national average (22% versus 2%, respectively), with unusual epidemiologic risk factors. Female Culex quinquefas-ciatus WNV positivity was low (2.7%), with viral phylogenetics 100% homologous to the WN02 clade. Mosquito vectors clustered in affluent urban neighborhoods …

Statistical Guarantees Of Deep Generative Models Involving Diverse Spaces: Generation Consistency And Robustness, Anish Chakrabarty

Doctoral Theses

Generative modeling focuses on the task of producing new data samples that closely resemble those drawn from an original, unknown distribution. Despite being well-known in statistical estimation theory, the approach has gained substantial traction in recent years, driven by groundbreaking results in areas such as image synthesis, natural language generation, and network modeling. The complexity of modern-era data domains and the ensuing adaptations that suitable models must undergo have presented new challenges. These advances raise several fundamental questions, the first of which is: When do generative models accurately approximate the true data distribution? One may also ask: How well do …

Cash Or Crash: Return To Player Percentages And Expected Value Of Crash Games, Robert H. Scott Iii, Mikhail M. Sher, Jonathan Daigle

UNLV Gaming Research & Review Journal

Crash games are a new type of casino game offered on some online gambling sites. The first crash game was created by the online cryptocurrency casino Bustabit. Other cryptocurrency casinos started offering their own versions of crash games. Now mainstream online casinos have developed their own crash games—notably Rocket by DraftKings. Crash games are easy to learn and play. They offer the opportunity to increase your bet by many hundreds of multiples—though, as we show when deriving expected values, these outcomes are rare. In this paper, we study the history of crash games and calculate theoretical values of crash game …

On Robust Estimation Of Multivariate Location And Scale With Applications, Soumya Chakraborty

Doctoral Theses

The principal objective of this thesis is, in a nutshell, to provide robust estimators of multivariate location and scale which have reasonable to high model efficiency but avoid high computational complexity so as to be practically useful in real problems. We utilize the minimum density power divergence (DPD) and the related philosophy to invoke robustness. There are some computational issues while minimizing the DPD in different multivariate set-ups. We will work on this problem rigorously and come up with three types of estimation procedures which are explicitly or implicitly related to the minimum DPD methodology, keeping the computational issue in …

Positive Solutions Of Semipositone Singular Three-Points Boundary Value Problems For Nonlinear Fractional Differential Equations, Xueyan Zhang, Zhaocai Hao, Martin Bohner

Mathematics and Statistics Faculty Research & Creative Works

This study introduces the existence of one positive solution for a specific category of semipositive singular three-point boundary value problems associated with Caputo fractional differential equations. The proof relies on the application of the Guo–Krasnosel'skii fixed point theorem. In the end, we provide an illustrative example.

A Note On Sufficient Dimension Folding For Regression Mean Function With Categorical Predictors, Bilin Zeng, Akim Adekpedjou, Xuerong Meggie Wen

Mathematics and Statistics Faculty Research & Creative Works

Multi-dimensional arrays are referred to as tensors. Tensor-valued predictors are commonly encountered in modern biomedical applications, such as electroencephalogram (EEG), magnetic resonance imaging (MRI), functional MRI (fMRI), diffusion-weighted MRI, and longitudinal health data. In survival analysis, it is both important and challenging to integrate clinically relevant information, such as gender, age, and disease state along with medical imaging tensor data or longitudinal health data to predict disease outcomes. Most existing higher-order sufficient dimension reduction regressions for matrix- or array-valued data focus solely on tensor data, often neglecting established clinical covariates that are readily available and known to have predictive value. …

Derivation Of An Updated Brief Multivariable Prediction Model To Detect Panic-Related Anxiety In Emergency Department Patients With Cardiopulmonary Complaints, Sharon C. Sung, Felicia J. L. Ang, Arul Earnest, Leslie E. C. Lim, Shreshtha Jolly, Gilaine Rui Ng, A. John Rush, Marcus E. H. Ong

Research Collection School of Social Sciences

Background Patients with panic related-anxiety (i.e., panic attacks or panic disorder) frequently present to emergency departments (EDs) with cardiopulmonary complaints but are often undiagnosed, which can lead to recurrent visits and prolonged distress. This study aimed to derive a new symptom-based multivariable diagnostic prediction model to detect panic-related anxiety in ED patients with cardiopulmonary symptoms.Methods We conducted a single-blind prospective derivation study over 15 months in the ED of a major tertiary hospital in Singapore. Patients presenting with symptoms of palpitations, chest pain, dizziness, or difficulty breathing were assessed using the Structured Clinical Interview for DSM Disorders (SCID) to diagnose …

Typeface: Machine-Viewing Gentrification On Storefront Imagery In Bedford-Stuyvesant, Brooklyn, Alexander Mcquilkin

Dissertations, Theses, and Capstone Projects

Gentrification—broadly, the replacement of a less powerful group by a more powerful one in an urban context—is oft-discussed in the popular press, but its definition is much-debated in the urban planning literature. Furthermore, academic treatments of displacement understandably focus on measurable yet fairly abstract indicators like changes in rent or income, whereas neighborhood change is often registered by residents on the ground using visual, but difficult-to-quantify markers like retail turnover. This project uses image recognition technology on a set of storefront photos to index the visual streetscape of a neighborhood, as well as to track changes to that portrait over …

Let's Play Uno! Training Mathematical Thinking With An Inclusive Card Game, Thierry Meyrath, Clara-Ioana Mincu, Antonella Perucca

Journal of Humanistic Mathematics

We explore probability exercises based on the game UNO. Excluding the Wild cards, the deck contains precisely 100 cards, which makes it convenient to express probabilities as percentages. We discuss the mathematical relation between cards that can be played after other cards. We also propose an algebraic exercise that relates several quantities, such as the number of cards left in the losing player’s hand. Finally, we argue that UNO is a very inclusive game: it is logistically easy to play, allows for players of different skill levels, and can be adapted to meet special needs. Beyond being playful exercises, our …

Estimasi Proporsi Pekerja Anak Pulau Maluku & Papua: Pendekatan Small Area Estimation Hierarchical Bayes Distribusi Beta, Apriani Sofiana, Fauzana Afininnas, Fachrol Mochti, Angga Prayoga, Shafira Husna, Nofita Istiana

Jurnal Ekonomi Kependudukan dan Keluarga

Pekerja anak merupakan isu krusial yang memerlukan penanganan segera untuk mendukung pencapaian target pembangunan global. Pengentasan isu ini menuntut ketersediaan data yang akurat hingga wilayah kecil guna mendukung perumusan kebijakan yang tepat sasaran. Penelitian ini bertujuan menduga proporsi pekerja anak usia 5–17 tahun di kabupaten/kota Pulau Maluku dan Papua tahun 2024 menggunakan metode Small Area Estimation (SAE) Hierarchical Bayes (HB) distribusi Beta. Lima variabel penyerta dari PODES dan regsosek dipilih melalui stepwise regression dan dieksplorasi secara spasial. Hasil pemodelan HB Beta Pulau Maluku dan Papua menunjukkan sebagian besar wilayah masih memiliki RSE tinggi. Untuk meningkatkan presisi, dilakukan klasterisasi wilayah sebelum …

Novel R Shiny Tool For Survival Analysis With Time-Varying Covariate In Oncology Studies: Overcoming Biases And Enhancing Collaboration, Yimei Li, Yang Qiao, Fei Gao, Jordan Gauthier, Qiang Ed Zhang, Jenna Voutsinas, Wendy Leisenring, Ted Gooley, Corinne Summers, Alexandre Hirayama, Cameron Turtle, Rebecca Gardner, Jarcy Zee, Qian Vicky Wu

Wills Eye Hospital Papers

PURPOSE: Our study is motivated by evaluating the role of hematopoietic cell transplantation (HCT) after chimeric antigen receptor T-cell (CAR-T) therapy for ALL, a debated topic. Because patients may receive HCT at different times after CAR-T infusion or never, HCT post-CAR-T should be considered as a time-varying covariate (TVC).

METHODS: Standard Cox models and Kaplan-Meier (KM) curves (naïve method) assume that TVC status is known and fixed at baseline, which can yield biased estimates. Landmark analysis is a popular alternative but depends on a chosen landmark time. Time-dependent (TD) Cox model is better suited for TVC although visualizing survival curves …

Handling Missing Data In Copd Research, Chia-Ying Chiu

ETDs from 2020-2029

Chronic Obstructive Pulmonary Disease (COPD) remains a major global health concern and one of the leading causes of death in the United States, affecting approximately 4.6% of adults and reaching a prevalence of 9.4% in Alabama according to 2024 National Health Interview Survey. The disease imposes a substantial burden on quality of life and healthcare costs and contributes to increased disability-adjusted life years and years of life lost, as highlighted by the 2022 Lancet Commission report. Despite its im-pact, COPD is frequently diagnosed only after irreversible lung damage has occurred, largely due to under-recognized symptoms and limited diagnostic tools. Early …

Statistical Analysis Of Log Transformation Effectiveness In Air Traffic Movement Forecasting During Covid-19 In South Africa, John Lehlaka Masekoameng

Journal of Aviation Technology and Engineering

This study evaluates the effectiveness of log transformation in enhancing multiple regression models used to forecast air traffic movements (ATMs) in South Africa during the COVID-19 pandemic. Using 60 monthly observations from October 2016 to September 2021, the analysis incorporates variables such as revenue, lockdown levels, COVID-19 metrics, exchange rates, gross domestic product, and population. Two models are compared: one using raw ATMs and another with log-transformed ATMs as the dependent variable.

While the untransformed model shows stronger explanatory power (R² = 0.904, adjusted R² = 0.891) compared to the log-transformed model (R² = 0.772, adjusted R² = 0.741), the …

Dietary Inflammatory Index And Risk Of Colorectal Cancer In Japanese Men, Ayaka Kotemori, Kumiko Kito, Motoki Iwasaki, Taiki Yamaji, James Hébert Scd, Junko Ishihara, Manami Inoue, Shoichiro Tsugane, Norie Sawada On The Behalf Of Jphc Study Group

Faculty Publications

Background/Objectives: Unhealthy lifestyles lead to chronic low-grade inflammation, increasing the risk of colorectal cancer. Few studies in East Asia have examined the association between the dietary inflammation potential and colorectal cancer incidence. Therefore, we aimed to investigate this association further in the Japanese population. Methods: This study included 38,807 men aged 45–74 years who participated in the Japan Public Health Center-based prospective study (JPHC Study). The energy-adjusted dietary inflammatory index (E-DII) was derived from a food frequency questionnaire. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models. Differences in risk due to a …

Estimation Of Net Premium For Flight Delay Insurance Using The Aggregate Loss Model: A Case Study Of Indonesia Otas, Azka Nurul Husna, Yulial Hikmah, Ira Rosianal Hikmah

Jurnal Vokasi Indonesia

Air transportation, as one of the most chosen transportation modes, is frequently susceptible to delays. Flight Delay Insurance offers a vital solution to mitigate the financial losses associated with this risk. Premium pricing is a key factor influencing the decision to purchase this insurance, particularly on Online Travel Agent (OTA) platforms where product offerings are often highly comparable. The aggregate loss method is employed herein to ascertain the net premium (or pure premium) price. The loss severity component (X) is modeled using an empirical distribution, while the loss frequency component (N) is modeled using a Negative Binomial distribution with parameters …

Determination Of Sample Size In Vaccine Trials, Meghna Bose

Doctoral Theses

Sample size determination is an important as well as delicate problem in clinical trials. Often, prior information available before the beginning of the trial is used to estimate the sample size. Hence, it is of importance to quantify the prior information available in terms of an Effective Sample Size (ESS). The problem of finding Effective Sample Size (ESS) in Phase II clinical trials, where toxicity and efficacy are the two components of the treatment response vector, is considered. In particular, one of the components is assumed to be binary, and the other is assumed to be continuous. Theoretical expressions for …