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Full-Text Articles in Physical Sciences and Mathematics

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren Jul 2020

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …


Latent Class Models For At-Risk Populations, Shuaimin Kang Jul 2020

Latent Class Models For At-Risk Populations, Shuaimin Kang

Doctoral Dissertations

Clustering Network Tree Data From Respondent-Driven Sampling With Application to Opioid Users in New York City There is great interest in finding meaningful subgroups of attributed network data. There are many available methods for clustering complete network. Unfortunately, much network data is collected through sampling, and therefore incomplete. Respondent-driven sampling (RDS) is a widely used method for sampling hard-to-reach human populations based on tracing links in the underlying unobserved social network. The resulting data therefore have tree structure representing a sub-sample of the network, along with many nodal attributes. In this paper, we introduce an approach to adjust mixture models …


The Limits Of Location Privacy In Mobile Devices, Keen Yuun Sung Jul 2020

The Limits Of Location Privacy In Mobile Devices, Keen Yuun Sung

Doctoral Dissertations

Mobile phones are widely adopted by users across the world today. However, the privacy implications of persistent connectivity are not well understood. This dissertation focuses on one important concern of mobile phone users: location privacy. I approach this problem from the perspective of three adversaries that users are exposed to via smartphone apps: the mobile advertiser, the app developer, and the cellular service provider. First, I quantify the proportion of mobile users who use location permissive apps and are able to be tracked through their advertising identifier, and demonstrate a mark and recapture attack that allows continued tracking of users …


Bayesian Methods For The Assessment Of Reporting Errors For Data-Sparse Population-Periods With Applications To Estimating Mortality, Emily Peterson Mar 2020

Bayesian Methods For The Assessment Of Reporting Errors For Data-Sparse Population-Periods With Applications To Estimating Mortality, Emily Peterson

Doctoral Dissertations

Population level mortality data is often subject to substantial reporting errors due to misclassification of cause of death, misclassification of death status, or age reporting errors. Accuracy of error-prone data sources can be assessed by comparing such data to gold standard data for the same population-period. We present Bayesian methods for assessing the extent of reporting errors across different population-periods and generalizing those to settings where gold-standard data are lacking. Firstly, we investigate misclassification errors of maternal cause of death reporting in civil registration vital statistics data. We use a Bayesian hierarchical bivariate random-walk model to estimate country-year specific sensitivity …


Nanoindentation Characterization Of Elastic Properties Of Shales And Swelling Clay Minerals, Shengmin Luo Mar 2020

Nanoindentation Characterization Of Elastic Properties Of Shales And Swelling Clay Minerals, Shengmin Luo

Doctoral Dissertations

Oil and gas shales are a class of multiscale, multiphase, hybrid inorganic-organic sedimentary rocks that consist of a generally uniform, preferentially oriented clay matrix with randomly embedded silt and sand particles as solid inclusions. A thorough understanding of the mechanical properties of shales is crucial for the exploration and production of oil and gas in the unconventional shale reservoirs, but it can be a challenging task due to their nature of compositional heterogeneity and microstructural anisotropy. In efforts to better characterize the mechanical properties of shales across different length scales and to fundamentally understand the laws of upscaling from individual …


Coxphlb: An R Package For Analyzing Length Biased Data Under Cox Model, Chi Hyun Lee, Heng Zhou, Jing Ning, Diane D. Liu, Yu Shen Jan 2020

Coxphlb: An R Package For Analyzing Length Biased Data Under Cox Model, Chi Hyun Lee, Heng Zhou, Jing Ning, Diane D. Liu, Yu Shen

Biostatistics and Epidemiology Faculty Publications Series

Data subject to length-biased sampling are frequently encountered in various applications including prevalent cohort studies and are considered as a special case of left-truncated data under the stationarity assumption. Many semiparametric regression methods have been proposed for lengthbiased data to model the association between covariates and the survival outcome of interest. In this paper, we present a brief review of the statistical methodologies established for the analysis of length-biased data under the Cox model, which is the most commonly adopted semiparametric model, and introduce an R package CoxPhLb that implements these methods. Specifically, the package includes features such as fitting …


The Incubation Period Of Coronavirus Disease 2019 (Covid-19) From Publicly Reported Confirmed Cases: Estimation And Application, Stephen A. Lauer, Kyra H. Grantz, Qifang Bi, Forest K. Jones, Qulu Zheng, Hannah R. Meredith, Andrew S. Azman, Nicholas G. Reich, Justin Lessler Jan 2020

The Incubation Period Of Coronavirus Disease 2019 (Covid-19) From Publicly Reported Confirmed Cases: Estimation And Application, Stephen A. Lauer, Kyra H. Grantz, Qifang Bi, Forest K. Jones, Qulu Zheng, Hannah R. Meredith, Andrew S. Azman, Nicholas G. Reich, Justin Lessler

Biostatistics and Epidemiology Faculty Publications Series

Background:

A novel human coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was identified in China in December 2019. There is limited support for many of its key epidemiologic features, including the incubation period for clinical disease (coronavirus disease 2019 [COVID-19]), which has important implications for surveillance and control activities.

Objective:

To estimate the length of the incubation period of COVID-19 and describe its public health implications.

Design:

Pooled analysis of confirmed COVID-19 cases reported between 4 January 2020 and 24 February 2020.

Setting:

News reports and press releases from 50 provinces, regions, and countries outside Wuhan, Hubei province, China. …


Development Of The Gambling Disorder Identification Test: Results From An International Delphi And Consensus Process, Olof Molander, Rachel Volberg, Viktor Månsson, Kristina Sundqvist, Peter Wennberg, Anne H. Berman Jan 2020

Development Of The Gambling Disorder Identification Test: Results From An International Delphi And Consensus Process, Olof Molander, Rachel Volberg, Viktor Månsson, Kristina Sundqvist, Peter Wennberg, Anne H. Berman

Biostatistics and Epidemiology Faculty Publications Series

Objectives

Diverse instruments are used to measure problem gambling and Gambling Disorder intervention outcomes. The 2004 Banff consensus agreement proposed necessary features for reporting gambling treatment efficacy. To address the challenge of including these features in a single instrument, a process was initiated to develop the Gambling Disorder Identification Test (GDIT), as an instrument analogous to the Alcohol Use Disorders Identification Test and the Drug Use Disorders Identification Test.

Methods

Gambling experts from 10 countries participated in an international two‐round Delphi (n = 61; n = 30), rating 30 items proposed for inclusion in the GDIT. Gambling researchers and …


Improved Viral Suppression With Streamlined Care In The Search Study, Matthew D. Hickey, James Ayieko, Dalsone Kwarisiima, Fredrick J. Opel, Asiphas Owaraganise, Laura B. Balzer, Gabriel Chamie, Vivek Jain, James Peng, Carol Camlin, Edwin D. Charlebois, Craig R. Cohen, Elizabeth A. Bukusi, Moses R. Kamya, Maya L. Petersen, Diane V. Havlir Jan 2020

Improved Viral Suppression With Streamlined Care In The Search Study, Matthew D. Hickey, James Ayieko, Dalsone Kwarisiima, Fredrick J. Opel, Asiphas Owaraganise, Laura B. Balzer, Gabriel Chamie, Vivek Jain, James Peng, Carol Camlin, Edwin D. Charlebois, Craig R. Cohen, Elizabeth A. Bukusi, Moses R. Kamya, Maya L. Petersen, Diane V. Havlir

Biostatistics and Epidemiology Faculty Publications Series

Background:

HIV differentiated service delivery (DSD) models are scaling up in resource-limited settings for stable patients; less is known about DSD outcomes for patients with viremia. We evaluated the effect on viral suppression (VS) of a streamlined care DSD model implemented in the SEARCH randomized universal test and treat trial in rural Uganda and Kenya (NCT:01864603).

Methods:

We included HIV-infected adults at baseline (2013) who were country guideline antiretroviral therapy (ART) eligible (prior ART experience or CD4 ≤ 350) with ≥1 HIV clinic visit between 2013 and 2017 in SEARCH communities randomized to intervention (N = 16) or control (N …


State Or Market? How To Effectively Decrease Alcohol-Related Crash Fatalities And Injuries, Jose I. Nazif-Muñoz, Brice Batomen, Youssef Oulhote, Arijit Nandi Jan 2020

State Or Market? How To Effectively Decrease Alcohol-Related Crash Fatalities And Injuries, Jose I. Nazif-Muñoz, Brice Batomen, Youssef Oulhote, Arijit Nandi

Biostatistics and Epidemiology Faculty Publications Series

Background It is estimated that more than 270 000 people die yearly in alcohol-related crashes globally. To tackle this burden, government interventions, such as laws which restrict blood alcohol concentration (BAC) levels and increase penalties for drunk drivers, have been implemented. The introduction of private-sector measures, such as ridesharing, is regarded as alternatives to reduce drunk driving and related sequelae. However, it is unclear whether state and private efforts complement each other to reduce this public health challenge.

Methods We conducted interrupted time-series analyses using weekly alcohol-related traffic fatalities and injuries per 1 000 000 population in three urban conglomerates …