Physical Sciences and Mathematics Commons^™

On The Hartogs Extension Theorem For Unbounded Domains In CN, Al Boggess, Roman Dwilewicz, Egmont Porten

Mathematics and Statistics Faculty Research & Creative Works

Let Ω ⊂ Cn, n > 2, be a domain with smooth connected boundary. If Ω is relatively compact, the Hartogs–Bochner theorem ensures that every CR distribution on ∂Ω has a holomorphic extension to Ω. For unbounded domains this extension property may fail, for example if Ω contains a complex hypersurface. The main result in this paper tells that the extension property holds if and only if the envelope of holomorphy of Cn \ Ω is Cn. It seems that it is the first result in the literature which gives a geometric characterization of unbounded domains in Cn for which the …

Fundamental Structure Of General Stochastic Dynamical Systems: High-Dimension Case, Haoyu Wang, Xiaoliang Gan, Wenqing Hu, Ping Ao

Mathematics and Statistics Faculty Research & Creative Works

No one has proved that mathematically general stochastic dynamical systems have a special structure. Thus, we introduce a structure of a general stochastic dynamical system. According to scientific understanding, we assert that its deterministic part can be decomposed into three significant parts: the gradient of the potential function, friction matrix and Lorenz matrix. Our previous work proved this structure for the low-dimension case. In this paper, we prove this structure for the high-dimension case. Hence, this structure of general stochastic dynamical systems is fundamental.

Nonlinear Mixed-Effects Models For Hiv Viral Load Trajectories Before And After Antiretroviral Therapy Interruption, Incorporating Left Censoring, Sihaoyu Gao, Lang Wu, Tingting Yu, Roger Kouyos, Huldrych F. Gunthard, Rui Wang

Harvard University Biostatistics Working Paper Series

Characterizing features of the viral rebound trajectories and identifying host, virological, and immunological factors that are predictive of the viral rebound trajectories are central to HIV cure research. In this paper, we investigate if key features of HIV viral decay and CD4 trajectories during antiretroviral therapy (ART) are associated with characteristics of HIV viral rebound following ART interruption. Nonlinear mixed effect (NLME) models are used to model viral load trajectories before and following ART interruption, incorporating left censoring due to lower detection limits of viral load assays. A stochastic approximation EM (SAEM) algorithm is used for parameter estimation and inference. …

A Predictive Model To Predict Cyberattack Using Self-Normalizing Neural Networks, Oluwapelumi Eniodunmo

Theses, Dissertations and Capstones

Cyberattack is a never-ending war that has greatly threatened secured information systems. The development of automated and intelligent systems provides more computing power to hackers to steal information, destroy data or system resources, and has raised global security issues. Statistical and Data mining tools have received continuous research and improvements. These tools have been adopted to create sophisticated intrusion detection systems that help information systems mitigate and defend against cyberattacks. However, the advancement in technology and accessibility of information makes more identifiable elements that can be used to gain unauthorized access to systems and resources. Data mining and classification tools …

Perception Of Health Care Access In Rural Georgia: Findings From A Community Health Needs Assessment Survey, Elisa M. Childs, Tiffany R. Washington

Journal of the Georgia Public Health Association

Background: Limited access to health care services has been cited as a barrier to care for individuals who live in rural areas, contributing to significant health disparities in this population. While perception of services has been cited as a determinant of utilization of health services, it is unknown how perception of services influences health care access in rural areas. The paucity of studies specific to areas in the United States that are medically underserved, necessitated this study and its quantification of the issues that are relevant to individuals living in rural Georgia.

Methods: This study examined the perception of health …

Stigma And Discrimination’S Effect On Hiv Testing Of Pregnant Women In Nigeria, Charles Echezona Nzelu

Walden Dissertations and Doctoral Studies

The utilization of HIV testing services among pregnant women in Nigeria has not been optimal. Although much is known about the determinants of HIV testing among pregnant women, there is a gap in knowledge on determinants for pregnant women infected with the virus, specifically whether stigma and discrimination are barriers. The purpose of this study was to examine the effect of stigmatizing attitudes and personal knowledge of discriminatory practices towards persons living with HIV/AIDS on the decision by pregnant Nigerian women aged 15-49 years to test for HIV during antenatal visits or childbirth. The health belief model served as the …

Opioid Use Disorder Treatment With Buprenorphine: Analysis Of Treatment Utilization And Associated Outcomes In Kentucky, Feitong Lei

Theses and Dissertations--Epidemiology and Biostatistics

Opioid use disorder (OUD) is chronic opioid use that results in clinically significant suffering, impairment, or even death. The opioid epidemic in the United States has become a public health and economic crisis, affecting patients' well-being and the nation's overall health and welfare. Eastern Kentucky was among the first regions affected by the opioid crisis, and Kentucky has historically ranked among the top five states for age-adjusted drug overdose mortality rate.

There are three medications (buprenorphine, methadone, naltrexone) approved by the U.S. Food and Drug Administration to treat OUD. As a partial opioid agonist, buprenorphine is a safe medication for …

The Three-Way Interplay Among Early Life Exposures, The Gut Microbiome, And Outcomes In Infancy, Yuka Moroishi

Dartmouth College Ph.D Dissertations

The bidirectional relationship between the gut microbiome and immune system plays an important role in host immune status: the immune system provides the gut microbiome the optimal environment to thrive in, and the gut microbiome helps regulate the immune system. This relationship is especially important in infants, whose immune system is still premature and rely on innate immunity.

We investigated the three-way interplay among early-life exposures, the developing gut microbiome, and outcomes in infancy from the general population in New Hampshire, US. We used prospective cohort data from the New Hampshire Birth Cohort study to 1) determine whether timing of …

Information Entropic Content Of Astrophysical Spectra: Applications To Cosmology And Astrobiology, Sara Vannah

Dartmouth College Ph.D Dissertations

Astrophysics faces two critical challenges: the difficulty of observing very distant targets and the difficulty of interpreting science in diverse and often extreme environments that have not been replicated on Earth. In this thesis, we discuss two types of spectra — one from early universe cosmology and one from astrobiology — where improvements in telescope technology are just ushering in a wave of precise observations, addressing the first challenge. This accelerates the need for a solution to the second challenge. Traditional methods for analyzing these two spectra rely heavily on unsettled science, biasing results to match the input assumptions. In …

Hitting It Out Of The Park: How Major League Baseball Changed The Game By Not Changing Anything At All, Kyle Sorgi

Honors Theses

In this paper, I will examine the integration of baseball into American culture and statistics’ involvement in that process. This paper will paint a clear picture of the emergence and acceptance of analytics in baseball through a gradual transformation of the style of play spanning the past few decades in the form of increased strikeouts, homeruns, and extra-base hits. Furthermore, this paper will explore the polarizing implications of analytical baseball on and off the field. One of the main questions that this paper will explore is whether or not MLB can go too far with its statistic-minded initiative (if it …

Think-Aloud Interviews: A Tool For Exploring Student Statistical Reasoning, A. Reinhart, C. Evans, Amanda Luby, J. Orellana, M. Meyer, J. Wieczorek, P. Elliott, P. Burckhardt, R. Nugent

Mathematics & Statistics Faculty Works

Think-aloud interviews have been a valuable but underused tool in statistics education research. Think-alouds, in which students narrate their reasoning in real time while solving problems, differ in important ways from other types of cognitive interviews and related education research methods. Beyond the uses already found in the statistics literature—mostly validating the wording of statistical concept inventory questions and studying student misconceptions—we suggest other possible use cases for think-alouds and summarize best-practice guidelines for designing think-aloud interview studies. Using examples from our own experiences studying the local student body for our introductory statistics courses, we illustrate how research goals should …

A Survey On The Use Of Plastic Versus Biodegradable Bottles For Drinking Water Packaging In The United Arab Emirates, Himadri Rajput, Munjed A. Maraqa, Fatima Zraydi, Lina A. Al Khatib, Noor Ameen, Rime Ben Elkaid, Safia S. Al Jaberi, Noura A. Alharbi, Reka Howard, Ashraf Aly Hassan

Department of Statistics: Faculty Publications

Due to intensive utilization and extensive production, plastic waste is becoming a serious threat to the environment and human health. The situation is even worse in countries such as the United Arab Emirates (UAE), where single-use plastic water bottles add to the load of plastic pollution. The main objective of this survey was to assess the extent of bottled water utilization by the UAE residents and their awareness of the environmental concerns arising from single-use plastic bottles. The aim was also to evaluate their willingness to shift towards using biodegradable plastic bottles. This study involved the feedback of 2589 respondents …

Seasonal Variation In Terrestrial Invertebrate Subsidies To Tropical Streams And Implications For The Feeding Ecology Of Hart’S Rivulus (Anablepsoides Hartii), David C. Owens, Thomas N. Heatherly, Kent M. Eskridge, Colden V. Baxter, Steven A. Thomas

Department of Statistics: Faculty Publications

Terrestrial invertebrates are important subsidies to fish diets, though their seasonal dynamics and importance to tropical stream consumers are particularly understudied. In this year-round study of terrestrial invertebrate input to two Trinidadian headwater streams with different forest canopy densities, we sought to (a) measure the mass and composition of terrestrial inputs with fall-in traps to evaluate the influences of seasonality, canopy cover, and rainfall intensity, and; (b) compare terrestrial and benthic prey importance to Anablepsoides hartii(Hart’s Rivulus), the dominant invertivorous fish in these streams, by concurrently measuring benthic and drifting invertebrate standing stocks and the volume and composition of …

Cranberry Polyphenols In Esophageal Cancer Inhibition: New Insights, Katherine M. Weh, Yun Zhang, Connor L. Howard, Amy B. Howell, Jennifer L. Clarke, Laura A. Kresty

Department of Statistics: Faculty Publications

Esophageal adenocarcinoma (EAC) is a cancer characterized by rapidly rising incidence and poor survival, resulting in the need for new prevention and treatment options. We utilized two cranberry polyphenol extracts, one proanthocyanidin enriched (C-PAC) and a combination of anthocyanins, flavonoids, and glycosides (AFG) to assess inhibitory mechanisms utilizing premalignant Barrett’s esophagus (BE) and EAC derived cell lines. We employed reverse phase protein arrays (RPPA) and Western blots to examine cancer-associated pathways and specific signaling cascades modulated by C-PAC or AFG. Viability results show that C-PAC is more potent than AFG at inducing cell death in BE and EAC cell lines. …

Genome-Wide Association Study Of Disease Resilience Traits From A Natural Polymicrobial Disease Challenge Model In Pigs Identifies The Importance Of The Major Histocompatibility Complex Region, Jian Cheng, Rohan Fernando, Hao Cheng, Stephen D. Kachman, Kyusang Lim, John C.S. Harding, Michael K. Dyck, Frederic Fortin, Graham S. Plastow, Piggen Canada Research Consortium, Jack C.M. Dekkers

Department of Statistics: Faculty Publications

Infectious diseases cause tremendous financial losses in the pork industry, emphasizing the importance of disease resilience, which is the ability of an animal to maintain performance under disease. Previously, a natural polymicrobial disease challenge model was established, in which pigs were challenged in the late nursery phase by multiple pathogens to maximize expression of genetic differences in disease resilience. Genetic analysis found that performance traits in this model, including growth rate, feed and water intake, and carcass traits, as well as clinical disease phenotypes, were heritable and could be selected for to increase disease resilience of pigs. The objectives of …

Kryging: Geostatistical Analysis Of Large-Scale Datasets Using Krylov Subspace Methods, Suman Majumder, Yawen Guan, Brian J. Reich, Arvind K. Saibaba

Department of Statistics: Faculty Publications

Analyzing massive spatial datasets using a Gaussian process model poses computational challenges. This is a problem prevailing heavily in applications such as environmental modeling, ecology, forestry and environmental health. We present a novel approximate inference methodology that uses profile likelihood and Krylov subspace methods to estimate the spatial covariance parameters and makes spatial predictions with uncertainty quantification for point-referenced spatial data. The proposed method, Kryging, applies for both observations on regular grid and irregularly-spaced observations, and for any Gaussian process with a stationary isotropic (and certain geometrically anisotropic) covariance function, including the popular Matérn covariance family. We make use of …

Identifying Patterns In The Structural Drivers Of Intrastate Conflict, Jonathan D. Moyer, Austin S. Matthews, Mickey Rafa, Yutang Xiong

International Studies: Faculty Scholarship

Quantitative methods have been used to: (1) better predict civil conflict onset; and (2) understand causal mechanisms to inform policy intervention and theory. However, an exploration of individual conflict onset cases illustrates great variation in the characteristics describing the outbreak of civil war, suggesting that there is not one single set of factors that lead to intrastate war. In this article, we use descriptive statistics to explore persistent clusters in the drivers of civil war onset, finding evidence that some arrangements of structural drivers cluster robustly across multiple model specifications (such as young, poorly developed states with anocratic regimes). Additionally, …

Comparison Of Caregiver- And Child-Reported Quality Of Life In Children With Sleep-Disordered Breathing, Phoebe Kuo Yu, Kaitlyn Cook, Jiayan Liu, Raouf S. Amin, Craig Derkay, Lisa M. Elden, Susan L. Garetz, Alisha S. George, Sally Ibrahim, Stacey L. Ishman, Erin M. Kirkham, S. Kamal Naqvi, Jerilynn Radcliffe, Kristie R. Ross, Gopi B. Shah, Ignacio E. Tapia, H. Gerry Taylor, David A. Zopf, Susan Redline, Cristina M. Baldassari

Statistical and Data Sciences: Faculty Publications

Objective. Caregivers frequently report poor quality of life(QOL) in children with sleep-disordered breathing (SDB).Our objective is to assess the correlation between care-giver- and child-reported QOL in children with mild SDBand identify factors associated with differences between caregiver and child report.

Study Design. Analysis of baseline data from a multi-institutional randomized trialSetting. Pediatric Adenotonsillectomy Trial for Snoring, where children with mild SDB (obstructive apnea-hypopnea index\3) were randomized to observation or adenotonsillectomy.

Methods. The Pediatric Quality of Life Inventory (Peds QL)assessed baseline global QOL in participating children 5 to12 years old and their caregivers. Caregiver and child scores were compared. Multivariable regression …

A Simple And Robust Alternative To Bland-Altman Method Of Assessing Clinical Agreement, Abhaya Indrayan Prof

COBRA Preprint Series

Clinical agreement between two quantitative measurements on a group of subjects is generally assessed with the help of the Bland-Altman (B-A) limits. These limits only describe the dispersion of disagreements in 95% cases and do not measure the degree of agreement. The interpretation regarding the presence or absence of agreement by this method is based on whether B-A limits are within the pre-specified externally determined clinical tolerance limits. Thus, clinical tolerance limits are necessary for this method. We argue in this communication that the direct use of clinical tolerance limits for assessing agreement without the B-A limits is more effective …

Análisis De Los Días De Mora Para La Cartera De Un Producto Financiero En Colombia, Una Aproximación A Partir De Las Series De Tiempo (2013 - 2018), Eleny Kottaridis Fernandez

Economía

La morosidad sobre la cartera de consumo evidencia un patrón que debe ser considerado en la toma de decisiones de las entidades financieras para una adecuada administración del riesgo crediticio teniendo en cuenta su alta volatilidad. En efecto, un desempeño económico desfavorable relacionado con algunos sectores financieros, las bajas tasas de crecimiento económico y mayores niveles de desempleo, incrementa la probabilidad del incumplimiento de las obligaciones de los hogares debido a la menor capacidad de pago por la reducción de sus ingresos. De acuerdo con estos impactos, las entidades financieras necesitan contar con mecanismos para abordar el pronóstico sobre el …

The Role Of Health Expenditure On Health Outcomes: Evidence In West Africa Countries., Festus Efosa Eriamiatoe

Graduate Research Theses & Dissertations

This study investigates the role of health expenditure on health outcomes in West Africa countries. Using the Grossman theoretical framework, other variables that affect health outcomes were also examined. Sixteen countries of West Africa with yearly data spanning between the period of 19 years (2000-2019) was used in this study. The health outcomes examined include life expectancy and neonatal and under-5 mortality rates. The regressors used in the study include domestic government health expenditure per capita, domestic private health expenditure per capita, external health expenditure per capita, carbon-dioxide emission metric ton per capita, human immunodeficiency virus (HIV), unemployment, GDP per …

Estimating The Statistics Of Operational Loss Through The Analyzation Of A Time Series, Maurice L. Brown

Theses and Dissertations

In the world of finance, appropriately understanding risk is key to success or failure because it is a fundamental driver for institutional behavior. Here we focus on risk as it relates to the operations of financial institutions, namely operational risk. Quantifying operational risk begins with data in the form of a time series of realized losses, which can occur for a number of reasons, can vary over different time intervals, and can pose a challenge that is exacerbated by having to account for both frequency and severity of losses. We introduce a stochastic point process model for the frequency distribution …

Data, Knowledge Practices, And Naturecultural Worlds: Vehicle Emissions In The Anthropocene, Lindsay Poirier

Statistical and Data Sciences: Faculty Books

This chapter details the various techno-cultural assemblages giving rise to data collected to model and measure anthropogenic worlds, arguing that data-based technologies both represent and co-produce the Anthropocene. It begins with a review of scholarship emerging at the intersection of science and technology studies and information studies that advances understanding of data infrastructure and knowledge practices, and their role within the anthropogenic assemblages that shape history. Drawing on a case study describing how vehicle emissions are measured and regulated in the US, I examine the materialities and mutability of technologies designed to produce data about air quality, along with the …

Behavioral Predictive Analytics Towards Personalization For Self-Management – A Use Case On Linking Health-Related Social Needs, Bon Sy, Michael Wassil, Helene Connelly, Alisha Hassan

Publications and Research

The objective of this research is to investigate the feasibility of applying behavioral predictive analytics to optimize patient engagement in diabetes self-management, and to gain insights on the potential of infusing a chatbot with NLP technology for discovering health-related social needs. In the U.S., less than 25% of patients actively engage in self-health management even though self-health management has been reported to associate with improved health outcomes and reduced healthcare costs. The proposed behavioral predictive analytics relies on manifold clustering to identify subpopulations segmented by behavior readiness characteristics that exhibit non-linear properties. For each subpopulation, an individualized auto-regression model and …

Length Of Stay In A Homeless Shelter And Mitigating Homelessness, Uwemedimo S. Etteyit

Walden Dissertations and Doctoral Studies

AbstractHomelessness is a major public health issue in the United States. Every night, thousands of people have no residence to call their own. Most homeless persons turn to homeless shelters for help. Despite the homeless shelters, the problem of homelessness persists. This study examined the concept that the length of time spent at a homeless shelter is related to the homeless persons mitigating their homelessness through home placement, jobs, and healthcare access. Homelessness was examined using the socioecological model with its attendant levels of influence. On the intrapersonal level, socioeconomic status, education, old age, veteran status, and disability were factors. …

Don’T Beep At Me: Using Google Maps Apis To Reduce Driving Anxiety, Daniel Chechelnitsky

Mathematics, Statistics, and Computer Science Honors Projects

Stress while driving is a significant issue that causes automobile incidents. Along with the physical injuries, there is often baggage and trauma associated with these accidents. Wearable health monitoring technology, like Smartwatches, has a real possibility to help people further understand the stress inducing processes of driving. Thus to help with this issue, I propose a Google Maps app extension called: "Don't Beep At Me". This project creates a map that is layered by heart rate instead of speed limit and has great potential to be useful for reducing driving anxiety.

A Comparison Of Stacking Methods To Estimate Survival Using Residual Lifetime Data From Prevalent Cohort Studies, Zhaoheng Li

Mathematics, Statistics, and Computer Science Honors Projects

Prevalent cohort studies are widely used for their cost-efficiency and convenience. However, in such studies, only the residual lifetime can be observed. Traditionally, researchers rely on self-reported onset times to infer the underlying survival distribution, which may introduce additional bias that confounds downstream analysis. This study compares two stacking procedures and one mixture model approach that uses only residual lifetime data while leveraging the strengths of different estimators. Our simulation results show that the two stacked estimators outperform the nonparametric maximum likelihood estimator (NPMLE) and the mixture model, allowing robust and accurate estimations for underlying survival distributions.

Analysis Of Minor League Rule Changes Effect On Stolen Bases, Zachary Houghtaling

Williams Honors College, Honors Research Projects

This study uses various statistical analyses to evaluate the justification of rule changes for Major League Baseball that were implemented within the Minor Leagues during the 2021 minor league season. The primary focus of the study is predicting how some of these Minor League rule changes could affect the stolen base success rate and the number of attempts per game within the Major Leagues. A survey was conducted to evaluate how fans feel about stolen bases within the current game and if rules should be altered to increase the number of stolen bases that occur. Additionally, recorded Major and Minor …

Applying Machine Learning Algorithms For Face Mask Detections, Mackenzie Frato

Williams Honors College, Honors Research Projects

Goal: Apply multiple machine learning techniques to Face Mask images to detect if a student is wear a Face Mask and/or wearing it incorrectly or not at all. Methodology: Use 2-3 different machine learning techniques to develop this program. Will choose these techniques as I research over the semester. The best technique will be the final one used, but many will be explored. Validation techniques will be used to see which is the best technique. Timeline: Choose Dataset - October 1st, Choose techniques - October 31st, Research techniques/validation - November 31st, Begin writing code - December 13th, Finish code - …

Guide To The Dr. L.S. Dederick Papers, 1908-1956, Undated, Orson Kingsley, Patrick Koetsch

Archives & Special Collections Finding Aids

Louis Serle (L.S.) Dederick was born in Chicago in 1883. He received his Ph.D. in Mathematics from Harvard University in 1909. From 1909 – 1917 he was a professor at Princeton University. From 1917 – 1924 he was professor at the U.S. Naval Academy in Annapolis, Maryland. In 1926 Dederick began working for the U.S. Army, Ordnance. During his time there he was the Associate Director of the Ballistic Research Laboratory at the Aberdeen Proving Grounds in Aberdeen, Maryland where he focused on ballistics research.

While Dederick worked as a mathematician at the Aberdeen Proving Grounds, he was involved with …