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Item Open Access Indoor Source Apportionment and Health Risk Assessment of Inorganic PM2.5 in a University Building in the UAE(Wiley, 2026-04-08)Indoor air quality (IAQ) is a growing public health concern, especially in environments where individuals spend the majority of their time, such as homes, educational institutions, and office environments. This study investigates the elemental composition, chemical speciation, source apportionment, and health risks associated with indoor PM2.5 in a university building in the United Arab Emirates over a 1-year period. An indoor sampling campaign was conducted following international standards, and elemental analysis was performed using energy-dispersive X-ray fluorescence (EDXRF) spectroscopy. Crystallographic phases and compound identification were performed using X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS), respectively. Positive Matrix Factorization (PMF v5.0) was applied to apportion pollution sources, while health risk assessments were conducted for trace element exposure based on methods from the US EPA and the Agency for Toxic Substances and Disease Registry (ATSDR). Key indoor PM2.5 contributors included mineral and resuspended dust, sea salt, and anthropogenic sources such as heavy oil combustion, traffic, and secondary aerosols. The health risk assessment showed that all analyzed elements (Cr, Mn, Al, As, Cu, Ni, Pb, Zn, and Mg) had hazard quotient values below 1, indicating no noncarcinogenic risk, and the carcinogenic risk values for As, Cr, Ni, and Pb were below the ATSDR’s threshold value of 1 ×10−6. Multiple-Path Particle Dosimetry modeling showed that approximately 75% of inhaled PM2.5 deposits in the respiratory system, with younger individuals (18 years old) exhibiting slightly lower deposition. After 5 days of exposure, alveolar retention reached 0.072 mg in 21-year-olds and 0.066 mg in 18-year-olds, indicating potential for prolonged internal deposition. The findings underscore the importance of continuous monitoring and mitigation strategies to improve IAQ in densely occupied indoor environments.Item Embargo Corporate Purpose, Tax Avoidance, Environment, and Social Accountability: Empirical Evidence(2026-03)Business Roundtable firms have faced intense scrutiny from investors, media, and the public following their 2019 “Statement on the Purpose of a Corporation,” which marked a shift from shareholder-centric governance to a stakeholder-focused approach. This shift has sparked debate over whether Business Roundtable firms are genuinely committed to social responsibility or merely using it as a branding strategy without implementing meaningful changes. This thesis examines this debate across three chapters. Chapter 1 provides an extensive review of the Business Roundtable, tracing the theoretical conversation, historical evolution, and membership composition using novel hand-collected data, as well as its growing prominence in the United States economy, lobbying power, and policymaking, with descriptive evidence highlighting its economic and political significance. Chapter 2 examines governance accountability by analyzing whether Business Roundtable firms align their tax behavior with their 2019 pledge. Using a difference-in-differences framework on United States public firms from 2004 to 2022, the chapter tests whether Business Roundtable members engage in higher levels of tax avoidance than non-Business Roundtable firms and whether their tax practices changed following the Statement. Chapter 3 extends the analysis to environmental and social accountability by leveraging RepRisk incident data to capture media-reported controversies and assess whether Business Roundtable firms experienced changes in environmental and social incidents relative to matched non-Business Roundtable firms, including heterogeneity across industries and political contexts. Overall, the thesis traces a theoretical path and provides empirical evidence on whether Business Roundtable firms’ public commitments are reflected in observable changes in tax avoidance and environment, social, governance incidents, thereby contributing to debates on corporate purpose, greenwashing, and the credibility of voluntary corporate pledges.Item Embargo Item Open Access Discriminating Fake and Real Smiles Using Electroencephalogram Signals With Convolutional Neural Networks(IEEE, 2022-08)Genuineness of smiles is of particular interest in the field of human emotions and social interactions. In this work, we develop an experimental protocol to elicit genuine and fake smile expressions on 28 healthy subjects. Then, we assess the type of smile expressions using electroencephalogram (EEG) signals with convolutional neural networks (CNNs). Five different architectures (CNN1, CNN2, CNN3, CNN4, and CNN5) were examined to differentiate between fake and real smiles. We transform the temporal EEG signals into normalized gray-scale images and perform three-way classification to classify fake smiles, genuine smiles, and neutral expressions in the form of subject-dependent classification. We achieved the highest classification accuracy of 90.4% using CNN1 for the full EEG spectrum. Likewise, we achieved classification accuracies of 87.4%, 88.3%, 89.7%, and 90.0% using Beta, Alpha, Theta, and Delta EEG bands respectively. This paper suggests that CNNs models, widely used in image classification problems, can provide an alternative approach for smile detection from physiological signals such as the EEG.
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