This dissertation examines the policy and socio-economic dynamics of the Venezuelan agrarian reform in the Chavista era. As a self-proclaimed socialist state, the Chavista government has framed its agrarian policies as a reordering of the food system that prioritized land redistribution, smallholder agriculture, and sustainable forms of production. The agrarian reform purported to place peasant farmers at the core of a new agricultural regime that would build national food sovereignty. Yet despite increased state support for smallholders, aggressive pro-peasant rhetoric, popular support for the Chavista party in rural areas, and oil wealth to fund agriculture development, rural dynamics have been characterized by conflict over land and a geographically and temporally uneven process of policy development in the countryside.

This dissertation argues that the land reform program in Venezuela has plateaued as a redistributive process and has to come to serve as primarily social rather than productive policy in rural areas. In this study I seek to analyze the determining factors that have impacted and restricted the agrarian reform process and produced this limited outcome.

To understand the limits of the agrarian reform I argue that it is necessary to examine policy processes within an analysis of the broader political economy of Venezuela as an oil state with a mixed economy. I also posit that analyses of agrarian dynamics that focus on peasant-state relationships without addressing the commercial agriculture sector have omitted a critical dimension of the agro-food system. I therefore take a multi-sectoral approach to agro-food policy that draws these understudied components of agrarian Venezuela—petro-state dynamics and the commercial agriculture sector—into an analysis anchored on peasant-state policy relationships.

Through this multi-sectoral approach I argue that the complex and often contradictory objectives of state policy in the agrarian realm are illustrative of macro-level, petro-state constraints on progressive reform more broadly, as well as tensions between political and economic development objectives of state policy. I show how oil dynamics create political economic challenges to structural change and feed into the construction of particular state ‘needs’ for agriculture, food production and agrarian reform. These dynamics help to explain the apparent contradiction of why much of state agricultural policy in Venezuela contributes to maintaining the viability and local economic position of large farmers even as government discourse continues to highlight the state’s promotion of agrarian reform and smallholder production.

I propose the term ‘petro-socialism’ to refer to the political economy emerging from the amalgam of oil state dynamics and the anti-neoliberal/socialist framing of the government’s policies. The concept of petro-socialism connotes that the shape of state reforms in the Chavista period were inherently constrained and often contradictory in nature.

Group II introns are DNA sequences that are interspersed throughout the genomes of organisms from all three domains of life. In many cases these intron genes interrupt coding sequences referred to as exons. In order for the exons to be expressed properly, the intervening intron sequence must first be removed. Once transcribed into pre-mRNA, the scattered introns become catalytic ribozymes and are able to efficiently excise themselves and ligate the flanking exons. These RNA molecules contain an active site capable of binding the catalytic metal ions required to perform two sequential transesterification reactions that cut out the intron sequence and paste the exons together. This mechanism is identical to the one used by the spliceosome to process spliceosomal introns from pre-mRNA in eukaryotes. The mechanistic similarities combined with conserved structural elements supports the hypothesis that group II introns and the spliceosome share a common evolutionary ancestor. In addition to their splicing function, group II introns also act as selfish mobile genetic elements known as retrotransposons. These active retroelements contain an open reading frame for a protein called the maturase. When expressed. this protein acts as a folding chaperone by binding specifically to the intron RNA to promote splicing activity. The maturase is a multifunctional protein containing reverse transcriptase and endonuclease domains allowing the group II intron/maturase complex to invade dsDNA through a target primed reverse transcription mechanism. Sequence homology and mechanistic similarities have evolutionarily linked group II introns to non-LTR retroelements, which make up approximately 34% of the human genome. Some of these retroelements are still active and are the cause of many genetic diseases. The focus of this dissertation is the structural study of group II introns to elucidate the mechanism of splicing and retrotransposition. Using cryo-EM, I have been able to obtain density maps at 5.8 Å resolution for a group II intron while splicing and 4.8 Å resolution for a group II intron actively invading dsDNA. The 4.8 Å map represents the first of its kind for any retroelement.

Ultrafast electron diffraction is a developing technique for recording the evolution of atomic structure during dynamic processes. While many exciting discoveries and important observations have been made so far, the technique still faces instrumentation, modeling, and other challenges that inhibit materials science studies, especially of quantum and nanoscale materials. In this dissertation, I describe several developments of UED technology and modeling capabilities to overcome these challenges as well as show a couple of scientific applications. I begin with a general introduction to UED and its value to materials science. I then describe the scattering theory underlying UED patterns and demonstrate a multislice approach that dramatically improves quantitative retrieval of atomic motions in crystals. After this, I introduce the High Repetition-rate Electron Scattering (HiRES) beamline, a state-of-the-art high-brightness UED setup which enables several advances in UED capabilities. I follow up by detailing the first scientific study using the beamline, where a unique light-induced structural melt-recovery process in a quantum material was recorded for the first time. I then show proof-of-principle demonstrations of nanoscale probing enabled by HiRES, including diffraction from isolated nanomaterials as well as focused nanoprobes for nanodiffraction and nanoimaging. Following this, I describe progress towards plasmon-enhanced nanoemitters and how they can be used to further improve the brightness of UED nanoprobes. Finally, I briefly tie together these varied developments and outline areas for further development and scientific exploration. Altogether, the work detailed here expands the reach of UED for study of quantum and nanoscale materials and lays groundwork for further advances that will enable new, wide-open frontiers in materials science.

Distributed Energy Resources (DER) have the potential to both improve the manner in which the electric power distribution system is operated and provide services to the bulk electric grid. A key question that has emerged in academic circles is the manner in which DER is governed to provide such utility. While many of the suggested approaches are mathematically elegant and demonstrate positive performance in simulations, they face enormous barriers to implementation due to their reliance on knowledge of network models and burdensome communications requirements. This dissertation focuses on the application of an Extremum Seeking (ES) control approach to manage individual DER, that does not require utility network models and or communication between agents. Results achieved from the application of this technique are shown to be equivalent to those derived from centrally-based optimization strategies that utilize convex relaxation techniques. Initially, I explore the use of Extremum Seeking to manage reactive power resources to perform voltage constrained optimization in balanced radial distribution systems. Next, also for balanced and radial distribution systems, I extend this work to consider the management of four-quadrant-capable DER to enable voltage-constrained distribution substation real power and voltage reference tracking. My approach essentially allows the distribution feeder to act as a controllable (P,V) bus when viewed from the perspective of the Transmission System Operator. Finally, in an attempt to extend my results to 3-phase distribution systems, I derive a linear approximation to unbalanced power flow and explore a new objective of using reactive power resources to regulate and balance system voltages. While the latter-most piece does not specifically consider ES, it lays the necessary foundation for the application of the approach in unbalanced systems.

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