Laser-Induced Breakdown Spectroscopy

The goal of this work is to use a Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) Laser, spectrometer, and computer to create a Laser Induced Breakdown Spectroscopy (LIBS) system. LIBS utilizes a focused, high-powered, pulsed laser whose peak electric field ionizes materials at the beam focal point, creating localized plasma. The plasma state includes broken molecular bonds, atom/electron-ionization, and excited electrons, which on the macroscopic level is a loud “snap” and a bright spark. In this project, a fiber optic cable is used to capture light emitted from the spark, and direct it into a spectrometer which tallies the number of photons at each wavelength, resulting in a characteristic spectrum of the light produced. Because each photon corresponds to a specific energy transition within the plasma, the spectrum can be used to determine the composition of the material and relative abundance of elements. With careful equipment synchronization, we were able to assemble and test a working computer-controlled LIBS system. Data is presented for various samples including the atmosphere and metallic coin surfaces

A Psychological Approach to the Special Composition Question

When does composition occur? There are historical accounts that claim there are no composite objects, or that composite objects can consist of any given objects. These views fail to preserve our intuitions and warrant a different understanding of the term “object”. I present a psychological approach wherein observers ascribe objecthood to an arrangement in the form of a secondary quality. This subjective behavior can be traced back to the development of our perceptual capacities in our natural history

An Evaluation Of Primary Care Based Social Needs Screening Implementation Among Community Health Centers In North Carolina

Structural social determinants of health (SDOH) and individual-level social needs drive health outcomes and widen health disparities. Successful efforts to reform health care delivery towards value and effective population health management requires health systems to assess and address social needs in routine outpatient clinical encounters. The Protocol for Responding to and Assessing Patients’ Assets, Risks, and Experiences (PRAPARE) was developed as a screening tool and corresponding clinical workflow to assess and respond to identified social needs that impact health. However, evidence on the cost of PRAPARE, the screening tool’s association with clinical risk, and patients’ perspectives on implementation is limited. In this dissertation, I examine these aspects of PRAPARE in federally-qualified health centers (FQHCs) across North Carolina. The first aim of this dissertation evaluates the relationship between PRAPARE responses and individuals’ cardiometabolic clinical risk. The second aim examines the direct clinic-level cost of implementing and sustaining a practice pattern change required for the PRAPARE screening and response protocol. The third aim assesses implementation barriers and facilitators of the PRAPARE social needs response protocol from the patient’s perspective. The findings are of interest to policy makers and payers interested in scaling this approach and provides practical implementation insights for health systems and practitioners interested in assessing and addressing individual-level social needs to improve care quality and promote health equity.Doctor of Philosoph

Food Insecurity and Social Policy: A Comparative Analysis of Welfare State Regimes in 19 Countries

We sought to determine whether a country's social policy configuration—its welfare state regime—is associated with food insecurity risk. We conducted a cross-sectional study of 2017 U.N. Food and Agriculture Organization individual-level food insecurity survey data from 19 countries (the most recent data available prior to COVID-19). Countries were categorized into three welfare state regimes: liberal (e.g., the United States), corporatist (e.g., Germany), or social democratic (e.g., Norway). Food insecurity probability, calibrated to an international reference standard, was calculated using a Rasch model. We used linear regression to compare food insecurity probability across regime types, adjusting for per-capita gross domestic product, age, gender, education, and household composition. There were 19,008 participants. The mean food insecurity probability was 0.067 (SD: 0.217). In adjusted analyses and compared with liberal regimes, food insecurity probability was lower in corporatist (risk difference: −0.039, 95% CI −0.066 to −0.011, p  =  .006) and social democratic regimes (risk difference: −0.037, 95% CI −0.062 to −0.012, p  =  .004). Social policy configuration is strongly associated with food insecurity risk. Social policy changes may help lower food insecurity risk in countries with high risk

MARTA Reach: Piloting an On-Demand Multimodal Transit System in Atlanta

This paper reports on the results of the six-month pilot MARTA Reach, which aimed to demonstrate the potential value of On-Demand Multimodal Transit Systems (ODMTS) in the city of Atlanta, Georgia. ODMTS take a transit-centric view by integrating on-demand services and traditional fixed routes in order to address the first/last mile problem. ODMTS combine fixed routes and on-demand shuttle services by design (not as an after-thought) into a transit system that offers a door-to-door multimodal service with fully integrated operations and fare structure. The paper fills a knowledge gap, i.e., the understanding of the impact, benefits, and challenges of deploying ODMTS in a city as complex as Atlanta, Georgia. The pilot was deployed in four different zones with limited transit options, and used on-demand shuttles integrated with the overall transit system to address the first/last mile problem. The paper describes the design and operations of the pilot, and presents the results in terms of ridership, quality of service, trip purposes, alternative modes of transportation, multimodal nature of trips, challenges encountered, and cost estimates. The main findings of the pilot are that Reach offered a highly valued service that performed a large number of trips that would have otherwise been served by ride-hailing companies, taxis, or personal cars. Moreover, the wide majority of Reach trips were multimodal, with connections to rail being most prominent

Applications and challenges of marker-assisted selection in the Western Australian Wheat Breeding Program

Interactions with the extracellular matrix (ECM) through integrin adhesion receptors provide cancer cells with physical and chemical cues that act together with growth factors to support survival and proliferation. Antagonists that target integrins containing the beta1 subunit inhibit tumor growth and sensitize cells to irradiation or cytotoxic chemotherapy in preclinical breast cancer models and are under clinical investigation. We found that the loss of beta1 integrins attenuated breast tumor growth but markedly enhanced tumor cell dissemination to the lungs. When cultured in three-dimensional ECM scaffolds, antibodies that blocked beta1 integrin function or knockdown of beta1 switched the migratory behavior of human and mouse E-cadherin-positive triple-negative breast cancer (TNBC) cells from collective to single cell movement. This switch involved activation of the transforming growth factor-beta (TGFbeta) signaling network that led to a shift in the balance between miR-200 microRNAs and the transcription factor zinc finger E-box-binding homeobox 2 (ZEB2), resulting in suppressed transcription of the gene encoding E-cadherin. Reducing the abundance of a TGFbeta receptor, restoring the ZEB/miR-200 balance, or increasing the abundance of E-cadherin reestablished cohesion in beta1 integrin-deficient cells and reduced dissemination to the lungs without affecting growth of the primary tumor. These findings reveal that beta1 integrins control a signaling network that promotes an epithelial phenotype and suppresses dissemination and indicate that targeting beta1 integrins may have undesirable effects in TNBC