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The Inflation Reduction Act has allocated over $369 billion to expedite the transition from fossil fuels to renewable energy. Along with these incentives, the funds support job training initiatives, like the recently introduced American Climate Corps. The transition to new energy forms will result in structural changes in the labor market and the demand for new and emerging skills, tasks, and jobs. A challenge, however, is that there are no existing definitions of what constitutes green jobs and skills, and thus, no clear consensus on the training workers will need for these jobs. This dissertation employs a data-driven approach using the Occupational Information Network to define and characterize green tasks, skills, and jobs. Using Natural Language Processing, we develop a method to quantify the "greenness'' of tasks and occupations. Utilizing this index, we explore the significant role of green skills during economic transitions. Our findings offer a comprehensive roadmap for understanding the evolution of green jobs and skills over the next decade. This dissertation comprises three chapters analyzing the tasks, skills, and jobs in the green economy. The first chapter investigates what constitutes green jobs and their characteristics. We construct "Task Greenness Scores" and "Occupational Green Potential" indices using Natural Language Processing and machine learning techniques to assess the greenness of tasks and overall occupations. Clustering methods categorize occupations based on task attributes -- green potential, frequency, importance, and relevance, identifying five distinct groups. This classification reveals significant variability in job greenness; although many jobs incorporate green tasks, only 113 occupations are definitively categorized as green. These are further divided into "High Green Intensity-Task Focus" and "High Green Intensity-Use Focus" groups, with the latter typically requiring less formal education and emphasizing manual skills over analytical or interactive skills. Our analysis also indicates a modest overall unconditional green wage premium of 3% for 2019 and 2020. The second chapter delineates green skills and maps their prevalence across the U.S., focusing on coal-mining communities in Appalachia. We sort a variety of skills into categories reflecting task and skill differences between green and non-green occupations, identified through O*NET. Principal Component Analysis helps categorize these into broader green skill groups such as "Technical Skills", "Management Skills", "Science Knowledge", and "Integrated Knowledge". The prevalence of green skills is notable in production-related occupations, suggesting essential technical expertise for the green economy. Interestingly, sectors traditionally viewed as energy-intensive also show a foundation conducive to green practices. Our findings highlight the necessity of tailored training programs that cater to diverse educational backgrounds, particularly emphasizing the lack of green skills in Appalachian regions, which may exacerbate inequalities during the economic transition. The third chapter examines the mediating role of green skills in local labor markets amidst the transition to a sustainable and energy-efficient economy. This chapter informs policy debates on large-scale green fiscal plans of the 2009 American Recovery and Reinvestment Act. We discover that regions well-prepared for environmental regulations or new energy development benefit from a robust stock of green skills. However, our analysis suggests that green ARRA investments are negatively correlated with wages and job creation, contrasting with positive correlations found in non-green ARRA investments. This chapter concludes that green skills significantly influence labor market outcomes, particularly in the manufacturing sector, and highlights the spillover effects of green stimulus on neighboring labor markets.

Spintronics is a vibrant research field that studies and utilizes the intrinsic spin properties of electrons in various materials. The dual states of spin (spin-up and spin-down) make it a natural candidate to represent the bit “0” or “1” in data storage and information processing. In the past two decades, a series of important discoveries in spintronics has been made in the labs and brought into the market. My research focus is to identify and investigate novel ferromagnetic and antiferromagnetic heterostructures that can be used to powerfully manipulate spins. This thesis is organized as follows: In Chapters 1 and 2, I briefly introduce the background knowledge in spintronics and the experimental as well as theoretical techniques that I use in my research. From Chapter 3 to 7, I present five research projects that I lead in my graduate study. In Chapter 3, we study a new nonlocal spin transport scheme. Compared with conventional nonlocal spin transport geometry where the spin current is generated through a ferromagnetic injector or spin Hall effect, in our scheme, spin current generation is through ferromagnetic resonance spin pumping in lateral Pt/Y3Fe5O12 heterostructures. This avoids the generation of high-energy thermal magnons through the spin Seebeck effect. We also observe a high spin current injection, which is more than 20 times larger than the local spin pumping in Pt/Y3Fe5O12, suggesting that the ultra-low damping bare Y3Fe5O12 is a much more efficient spin pumping source; In Chapter 4, we study the spin current transportation in Pt/NiO/Y3Fe5O12 trilayers through angular dependent ferromagnetic resonance spin pumping measurements. By systematically varying the temperatures and thicknesses of NiO, we observe spin current transport that is mediated by the antiferromagnetic NiO interlayer, which gives a non-sinusoidal angular dependence of inverse spin Hall voltage; In Chapter 5, we study current-induced Neel order switching in antiferromagnetic heterostructure Pt/α-Fe2O3. We demonstrate that the detected Hall resistance change is indeed due to the Neel order switching by carefully ruling out the thermal artifact from Pt. Our results point to a promising path toward controlling antiferromagnets using spin-orbit torque; In Chapter 6, we study the harmonic Hall response experimentally and theoretically in antiferromagnetic heterostructure Pt/α-Fe2O3. We build a theoretical model that proves the current-induced effects in antiferromagnetic heterostructures can be also detected by harmonic Hall technique like previously demonstrated in ferromagnetic heterostructures. Our experimental measurement is in excellent agreement with our modeling, which points out the important role played by the magnetoelastic effect and spin-orbit torque in current-induced switching of antiferromagnets; In Chapter 7, we make Hall measurements in antiferromagnetic heterostructure Pt/Cr2O3 bilayers and observe the high-temperature topological Hall effect. This indicates the nontrivial topological spin texture at Pt/Cr2O3 interface, which gives insights in searching skyrmions in antiferromagnets. The last chapter is a conclusion of the entire thesis.

This study examines the effect of SEC tax comment letters on institutional investors’ information acquisition activities and consequential tax disclosures. These two research questions are related to the SEC’s mission to protect investors, which is the primary objective of the SEC’s comment letter public release policy. Regarding the first research question, I find that institutional investors’ information acquisition activities for tax-related comment letter conversations, which include recipient firms’ responses, are greater than those for non-tax related conversations. Moreover, institutional investors are more likely to obtain comment-letter conversations for recipient firms that have appeared to be tax aggressive in both current and previous years. Institutional investors are more likely to obtain comment-letter conversations if the SEC comment letters include more uncertain tax topics. Regarding the second research question, I find a significant increase in the number of words in both tax footnotes and paragraphs but with slightly reduced readability, suggesting that managers modify the consequential tax disclosures with their own purposes.This research achieves several aims. First, the findings of this study contribute to the understanding of the consequences of receiving comment letters and their resolution. Second, this study contributes to the literature investigating investors’ acquisition of tax-related information. This paper also contributes to tax information disclosure literature as well as to the literature on textual analysis in accounting and finance. The findings of this study will have implications for regulators, investors, and corporate managers.

During the past century, impacts of climate change on both natural and human systems have been observed worldwide. Numerous scientific investigations suggest a strong correlation between the global warming and greenhouse gas (GHG) emissions. CO2 emission accounts for 78% of the GHG emissions, and 35% of this CO2 comes from electricity generation. Reduction of GHG emission from the electricity generation would therefore be beneficial to decrease global warming. As a renewable energy source, in comparison with conventional fossil fuels, solar energy has limitless supply, is accessible in most geographic locations, and is much cleaner. Currently, solar energy is economically viable in areas where the infrastructure is limited, or the GHG emissions are restricted by policy. To further facilitate the ubiquitous deployment of solar energy on a tera-watt utility scale, further increases in power conversion efficiency and reductions in cost are still required of solar cell technology. Third generation solar cells are emerging solar cell technologies, which are predicted to operate beyond the Shockley-Queisser limit for single bandgap cells. Nanostructured materials are under investigation as potential candidates for next generation photovoltaic technologies. In this dissertation, one type of nanostructured material, semiconductor quantum dots (QDs), were studied for their potential applications for next-generation photovoltaics. Epitaxial self-assembled InAs/GaAsSb QD solar cells are investigated for applications as intermediate band solar cells. These systems have a theoretical efficiency of $\sim$ 50\% with a simple single junction design. Two sets of optical InAs/GaAsSb QD samples grown by Molecular Beam Epitaxy (MBE), one set with various InAs deposition thicknesses, and the other set with different percentages of Sb composition in the barrier, were studied to determine the optimal growth conditions in terms of QD density and uniformity. A deposition thickness of 3 monolayers (ML) and 14% Sb matrix composition were shown to yield uniform QDs with the highest QD density ~ 3.5 X 10^11 /cm^2$ and a quasi-flat valance band alignment. Four p-i-n GaAs solar cells with different intrinsic region designs were then grown by MBE. An unusually large reduction of the Voc and a complex behavior of Jsc were both observed. A detailed experimental investigation of these devices supports the hypothesis that thermal activation of defects or ionization of impurities in the lattice induces a transition from that dominated by radiative recombination to non-radiative processes. This results in a quenching of the photoluminescence and electroluminescence intensity and a decrease the z-factor from 2 to 1, with increasing temperature. The 1.1% lattice mismatch between the GaAs substrate and GaAsSb matrix contributes to the defect formation, which serves as the main limitation of the performance of InAs/GaAsSb quantum dot solar cells presented in this work. PbS/ZnO colloidal QD solar cells are investigated for thin film solar cell applications. A suite of transport characterization techniques including current-voltage, capacitance-voltage, and impedance spectroscopy were used to study the effect of the interfaces and intrinsic surface states in a standard ITO/ZnO/PbS/Au colloidal quantum dot solar cell, without any passivation. An unintentional Schottky barrier formed at the PbS/ZnO interface results in Fermi level pinning and induces a non-linearity in the diode characteristic of this solar cell. Losses associated with Shockley-Reed-Hall recombination processes through interfacial and midgap states associated with the surface states on the PbS QDs contributes to a low minority carrier diffusion length, serving to inhibit the performance of the CQD solar cells.

The objective of this study was to identify sarcoplasmic proteins responsive to incubation temperature in Pekin duck embryos. Previous studies reported that a 1-degree Celsius increase in incubation temperature during the first 10 days can accelerate embryonic development and this study was designed to identify the effects of early incubation temperature on embryonic myogenesis. Pekin duck eggs were incubated at 37.5 degrees Celsius or 38.5 degrees Celsius for the first ten days and subsequently transferred to 37.5 degrees Celsius for the rest of incubation (ED 11-28). The embryonic pectoralis muscle (PM) was collected at ED12, 18, 25 and hatch and sarcoplasmic proteins were subjected to 10% SDS-PAGE. Gels were digitized into TotalLabTM to acquire the mean band percentage (MBP) of bands. The body weight (BW) of embryos and pectoralis muscle weight (PMW) of the Pekin duck embryos were analyzed in SAS 9.3. An acceleration in BW at ED12 in the 38.5 degrees Celsius treatment was observed but not at later ages. MIXED model is performed to determine bands responding significantly to incubation temperature. Three proteins/bands are determined to significantly respond to temperature.