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\u27A Visual Anecdote of the Passive Aggressive Fight Against Traditionally Gendered Bathrooms\u27
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Wasm-PBChunk: Incrementally Developing A Racket-To-Wasm Compiler Using Partial Bytecode Compilation
Get PDFRacket is a modern, general-purpose programming language with a language-oriented focus. To date, Racket has found notable uses in research and education, among other applications. To expand the reach of the language, there has been a desire to develop an efficient platform for running Racket in a web-based environment. WebAssembly (Wasm) is a binary executable format for a stack-based virtual machine designed to provide a fast, efficient, and secure execution environment for code on the web. Wasm is primarily intended to be a compiler target for higher-level languages. Providing Wasm support for the Racket project may be a promising way to bring Racket to the browser.
To this end, we present an incremental approach to the development of a Racket- to-Wasm compiler. We make use of an existing backend for Racket that targets a portable bytecode known as PB, along with the associated PB interpreter. We per- form an ahead-of-time static translation of sections of PB into native Wasm, linking the chunks back to the interpreter before execution. By replacing portions of PB with native Wasm, we can eliminate some portion of interpretation overhead and move closer to native Wasm support for Chez Scheme (Racket’s Backend). Due to the use of an existing backend and interpreter, our approach already supports nearly all features of the Racket language – including delimited continuations, tail-calling behavior, and garbage collection – and excluding threading and FFI support for the time being.
We perform benchmarks against a baseline to validate our approach, to promising results
Effects of arbuscular mycorrhizal fungi inoculation and cover crop on soil carbon dynamics and microbial communities in a Mediterranean lemon orchard.
Get PDFPlant-associated fungi such as arbuscular mycorrhizal fungi (AMF) have the potential to sequester carbon (C), improve soil aggregation, and promote plant health. Due to multiple benefits of AMF to plant and soil health, AMF has gained much attention leading to a rapidly expanding market in mycorrhizal bio-stimulants intended to improve crop yield, root development, and soil health in horticultural crops, including citrus. However, there is limited information on how to inoculate a mature citrus orchard, and how inoculation of a mature orchard with AMF affects C sequestration. In this study, we planted a cover crop inoculated with AMF in a mature lemon orchard and investigated the influence of the cover crop and AMF inoculation on C dynamics and the soil microbial community across the orchard floor. The experimental design was a Randomized Complete Block Design (RCBD) with three blocks and the following treatments applied in the alleyways: a cereal cover crop (Secale x Triticum L.) inoculated with AMF (Rhizophagus intraradices) at seeding, a cereal cover crop without inoculation, and a control where orchard alleys were left fallow. After two years of treatment implementation, soils were collected from each treatment plot from two functional locations, the tree row and the alley way, and two depth increments of 0-6 and 6-18 inches in order to asses soil C dynamics. To assess legacy effects of three years of practice implementation on soil C dynamics and microbial community structure, soils were collected at 0-6 inches depth from four functional locations: location one was between two trees on a berm, location two was in the transition section where the berm ends but no cover crop is grown, location three was on the edge of the cover cropped area (weeds in control plots), and location four was in the center of the alley row. AMF inoculation had no significant effects on soil C dynamics indicators such as total soil C, permanganate oxidazable carbon (POXC), mineralazable carbon (Min C), and soil aggregation. Likewise, AMF inoculation had no significant effect on microbial community biomass assesed with soil phospholipid fatty acids (PLFA) and neutral lipid fatty acids (NLFA). We attributed similarities between treatments to the non-inoculated cereal cover crop and weeds in the control treatment promoting native AMF. Across treatments, alley rows supported higher microbial community biomass and had higher total soil C (%), POXC (mg C/kg soil), and Min C (mg C/kg soil/day) than the tree row after three years of treatment implementation. After two years of treatment implementation, total soil C, Min C, and small macroaggregates (%) were higher in the topsoil in the cover cropped alley row compared to the topsoil in the three rows. We attribute the greater values for C cycling indicators and microbial abundance in the alley rows compared to the tree rows to positive impacts of tree prunings, weeds and cover crops and negative impacts of dry wet cycles in the alley versus tree rows, respectively. Correlation analysis showed that AMF and saprophytic fungi were significantly correlated with bacteria but not among themselves suggesting potential fungal-bacterial cooperation and niche differentiation between saprophytic fungi and AMF. In addition, correlation analysis showed that AMF and saprophytic fungi NLFA biomass was not significantly correlated with soil C indicators which contrasts other findings where fungi were key organisms in soil C accumulation. To summarize, AMF inoculation had no significant effect on soil C dynamics or the microbial community whereas differences in management between the tree and alley rows had a strong influence on soil C dynamics, microbial community biomass, and native AMF promotion in the lemon orchard
Interactive Water Vortex Exhibit
Get PDFThe San Luis Obispo Children’s Museum requested an interactive water vortex exhibit to both engage and entertain inquisitive guests, ages two to eight. The goal was to design and manufacture an exhibit that would educate its users on the fluid mechanics behind water vortices. They activate the mechanics by spinning a wheel, which is perceived as the catalyst to manipulate the flow of water to successfully create a whirlpool. Our team has created an interactive display that will enlighten young minds, providing the museum with an educational exhibit which shares a concept not currently taught by any other. Our project takes the manual input, as provided by a child, and translates it to a digital signal that can be read by a motor, to spin a magnet, that creates enough speed to spiral the water. The final prototype was manufactured and tested to allow children to provide minimal input to produce a water vortex
AN ECOLOGICAL ASSESSMENT OF AN ENDANGERED LICHEN FROM CENTRAL CALIFORNIA: SULCARIA ISIDIIFERA, THE SPLITTING YARN LICHEN
Get PDFLichens are an underrepresented group of organisms when it comes to both research and conservation efforts. At the same time, lichens face increasing threats from anthropogenic sources including wildfires, climate change and urbanization. With this thesis, I seek to ascertain and publish ecological data on a critically endangered lichen to inform future conservation designations and efforts to preserve and protect the species in perpetuity.
In Chapter 1, I provide an ecological overview of the known range of Sulcaria isidiifera and assess the status of Sulcaria isidiifera via a population count. Sulcaria isidiifera occurs in maritime chaparral habitat in the Los Osos-Baywood Park-Morro Bay area of San Luis Obispo County, California. Although apparently similar maritime chaparral is known from a much larger range along the coast of California, S. isidiifera has never been found outside of this extremely local population area. Population data collected during the study determined there are an estimated 3,588-7,772 mature individuals of S. isidiifera range-wide. Chapter 1 also characterizes the vascular plant vegetation community, microclimate parameters, and lichen community assemblage in which S. isidiifera occurs. The elegant fringe lichen (Leucodermia leucomelos) was found to be a strong indicator for the presence of S. isidiifera. Chamise (Adenostoma fasciculatum), buck brush (Ceanothus cuneatus), and Morro manzanita (Arctostaphylos morroensis) were the most common shrub species on which S. isidiifera was found.
In Chapter 2, conservation translocation was tested as a mitigation strategy for the previously observed population decline of S. isidiifera. Whole thalli were translocated while attached to their original substrate to adjacent shrubs in suitable habitat that was not occupied by S. isidiifera. The vitality of translocated thalli was tested using chlorophyll fluorescence techniques. After 13.5 months, I report 100 percent survival of translocated thalli with no significant negative impacts to thallus health. The S. isidiifera transplants will continue to be monitored indefinitely. Guidance on future conservation translocations for S. isidiifera is provided and these methods will continue to be updated as further observations and results are gathered
Decentralized Machine Learning On Blockchain: Developing A Federated Learning Based System
Get PDFTraditional Machine Learning (ML) methods usually rely on a central server to per-form ML tasks. However, these methods have problems like security risks, datastorage issues, and high computational demands. Federated Learning (FL), on theother hand, spreads out the ML process. It trains models on local devices and thencombines them centrally. While FL improves computing and customization, it stillfaces the same challenges as centralized ML in security and data storage.
This thesis introduces a new approach combining Federated Learning and Decen-tralized Machine Learning (DML), which operates on an Ethereum Virtual Machine(EVM) compatible blockchain. The blockchain’s security and decentralized naturehelp improve transparency, trust, scalability, and efficiency.
The main contributionsof this thesis include:1. Redesigning a semi-centralized system with enhanced privacy and the multi-KRUM algorithm, following the work of Shayan et al..2. Developing a new decentralized framework that supports both standard anddeep-learning FL, using the InterPlanetary File System (IPFS) and EthereumVirtual Machine (EVM)-compatible Smart Contracts.3. Assessing how well the system defends against common data poisoning attacks,using a version of Multi-KRUM that’s better at detecting outliers.4. Applying privacy methods to securely combine data from different sources
Deep Learning Recommendations for the ACL2 Interactive Theorem Prover
Get PDFDue to the difficulty of obtaining formal proofs, there is increasing interest in partially or completely automating proof search in interactive theorem provers. Despite being a theorem prover with an active community and plentiful corpus of 170,000+ theorems, no deep learning system currently exists to help automate theorem proving in ACL2. We have developed a machine learning system that generates recommendations to automatically complete proofs. We show that our system benefits from the copy mechanism introduced in the context of program repair. We make our system directly accessible from within ACL2 and use this interface to evaluate our system in a realistic theorem proving environment
Phase Distribution of Nickel, Chromium, and Cobalt in Seawater at Olivine-Enriched Beaches: Implications for Carbon Capture by Enhanced Silicate Weathering
Get PDFThe application of olivine to coastal areas is a proposed method of removing carbon dioxide from the atmosphere for climate change mitigation. Olivine is abundant and dissolves relatively fast, but it contains trace amounts of nickel (Ni), chromium (Cr), and cobalt (Co) which may be toxic to marine biota in cases of widespread coastal olivine spreading. Prior studies have suggested that Ni concentrations in marine sediments and/or the overlying water column due to olivine dissolution could be a limiting factor for its carbon capture potential. Therefore, it is critical to understand and model the processes affecting trace metal bioavailability after olivine application. This research used sand and sediments collected from a natural olivine beach (Papakōlea) and a black sand control beach (Richardson) in Hawaii to measure the adsorption of Ni, Cr, and Co to suspended particulate matter (SPM) in the water column and to beach sediments in equilibrium with pore water. The experimentally derived adsorption isotherms were then used for phase distribution modeling in the water column and sediment pore water at both sites.
Cr was observed to readily precipitate in seawater without suspended solids, meaning its exposure pathway for marine organisms will likely be via sediment, regardless of interactions with solid phases. Co uptake from solution may have been influenced by biological processes based on its continuous adsorption over 30 days, but more study ofcobalt adsorption to SPM is required because of conflicting results in a repeated experiment. Thus, Ni was the focus of the phase distribution modeling in this work.
Ni adsorption from seawater to SPM generated from both Papakōlea and Richardson sediments followed Langmuir adsorption models. Parameters for Ni adsorption to SPM from Papakōlea at pH 7.81 were KL = 2.74 L/kg and qmax = 931 mg/kg and for Richardson SPM at pH 8.00 they were KL = 5.69 L/kg and qmax = 1446 mg/kg. Ni adsorption to SPM was strongly affected by pH with the qmax for Richardson SPM nearly eight times greater at pH 8.00 than at pH 7.77. Ni adsorption to Papakōlea SPM was five times greater than Ni adsorption to Richardson SPM at comparable pH.
Ni adsorption to beach sediments from both sites was measured for five pHs between 7.27 and 8.73. Ni adsorption was observed to be strongly affected by pH and sediment type. A significant adsorption edge was observed for the Papakōlea sediment between pH 8.00 and 8.22, while a gradual increase in adsorption was observed between pH 7.27 and pH 8.15 for the Richardson sediment.
Ni adsorption to the beach sediments from pore water at the typical seawater pH of 8.05 was calculated by interpolation between adsorption models at surrounding pH values. Calculated Ni adsorption to Papakōlea sediment at pH 8.05 was linear with Kd = 22.4 L/kg while Ni adsorption to Richardson sediment at pH 8.05 followed a Langmuir model with KL = 0.8 L/kg and qmax = 179 mg/kg.
Phase distribution models constructed with the experimentally derived adsorption isotherms predicted that over 85% of the Ni in the water column is dissolved. This result was similar for the water columns at both beaches and was based on typical coastal total suspended solids (TSS) concentrations (5-20 mg/L). Therefore, it is predicted that transport of Ni into marine sediments by SPM settling is much smaller than bulk transport of dissolved Ni into the open ocean.
In contrast, the pore water models predict that over 95% of total Ni is adsorbed to the solid phase for both sediments. In a scenario where dissolved Ni concentration in the pore water is the maximum safe level of 8.2 ppb (US EPA environmental quality standard; EQS), Ni adsorbed to the sediment at both sites is predicted to be less than 10% of safe levels, the Florida Department of Environmental Protection’s threshold exposure limit (TEL) of 15.9 mg Ni per kg of sediment. These adsorbed Ni concentrations are likely a better indicator of threshold sediment Ni concentrations because presumably Ni adsorbed to sediments is more readily bioavailable than Ni in the structure of the olivine. In this case, dissolved Ni would be of more environmental concern than Ni in seabed sediments at sites of olivine enrichment. However, it will be important to investigate the bioavailability of Ni directly from the olivine structure to confirm this conclusion.
If dissolved Ni concentration in the pore water is the limiting factor for safe application of olivine, then olivine loading rates should be based on site-specific conditions (mixing regime and the residence time of seawater in the sediment pores) to maintain a dissolved Ni concentration less than the EQS. For Papakōlea Beach, with 70% olivine in thesediments, the dissolved Ni concentrations in the pore waters were measured to be at background seawater concentrations. This is likely because of the rapid mixing and high- energy wave action at this beach. Under these conditions, very little Ni would be adsorbed to the sediments.
Additional site-specific studies of Ni and Co adsorption to beach sediments should be conducted to gain a more complete understanding of the fate and transport of these trace metals and the risks posed to coastal ecosystems by their release. More experiments are needed to characterize Co adsorption in seawater to SPM and beach sediment. Additionally, Ni adsorption experiments should be performed on a wider variety of beach sediments to estimate its fate and transport at specific locations of potential olivine enrichment. Also, Ni adsorption to Papakōlea SPM was measured at pH 7.81, and since adsorption is expected to be much greater at seawater pH, the Ni adsorption experiment should be repeated at a pH greater than that of seawater to allow the construction of adsorption isotherms for Papakōlea SPM at seawater pH by interpolation. Additionally, experiments need to be conducted to determine the bioavailability of trace metals in the olivine itself and adsorbed to the olivine