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Hentai Beetle
No full textOne morning, a few years ago, I suddenly found myself immobilized, unable to get out of bed. In retrospect, perhaps I was a little tired with simultaneously juggling multiple projects, navigating a cross-continental move, and grappling with the bureaucratic intricates of extending my residence permit. Fortunately, the condition did not last long for me. However, while lying on bed, I scanned my eyes across the ceiling, and felt like this situation would continue in eternity. There are many analyses of Franz Kafka’s “Metamorphosis”. However, this experience has made me realize that this phenomenon of turning into an insect just may be more common and familiar to us than we imagine it to be."Hentai" is a Japanese word meaning "metamorphosis" or "change of form"
Impacts of Disulfide‐Containing Monomers in Alternating Diene Metathesis Polymerization
Get PDFABSTRACT Among the classes of synthetic polymers, disulfide‐containing structures offer unique opportunities due to their accessibility to redox chemistry that allows for degradation or reversible disulfide formation and exchange under mild conditions. Here, we examine the role of disulfides in olefin metathesis polymerization, specifically alternating diene metathesis (ALTMET) polymerization, for synthesizing unsaturated polyolefins with embedded disulfides. Our synthetic strategy hinged on the use of α,ω‐diacrylate monomers, including those connected by a disulfide unit, via copolymerization by the ALTMET mechanism to yield copolymers containing a range of disulfide content. In addition, the potential impacts of sulfur‐ruthenium interactions on the ALTMET process were investigated spectroscopically, while the degradation of the resultant polymers was affected by mild reducing agents. Overall, this study contributes to the development of degradable synthetic polymers using olefin metathesis methods, with an increased understanding of the potential for further use of disulfide groups in such metathesis reactions
Fast growth and high-titer bioproduction from renewable formate via metal-dependent formate dehydrogenase in Escherichia coli
No full textMicrobial bioproduction using one-carbon (C1) feedstocks has the potential to decarbonize the manufacturing of materials, fuels, and chemicals. Formate is a promising C1 feedstock, and the realization of industrial, formatotrophic platform organisms is a key goal for C1-based bioproduction. So far, a major limitation for synthetic formatotrophy has been slow energy supply due to slow formate dehydrogenase activity. Here, we implement a fast, metal-dependent formate dehydrogenase complex in a synthetic formatotrophic Escherichia coli utilizing the reductive glycine pathway. After a short-term evolution, we demonstrate formatotrophic growth of E. coli with a doubling time of less than 4.5 h, comparable to the fastest natural formatotrophs. To further explore the potential of a formate-based bioeconomy, this strain is engineered to produce mevalonate, as well as the terpenoid and aviation fuel precursor isoprenol, using formate we generate directly from the electrochemical reduction of CO2. This work demonstrates an improvement in bioproduct titer from formate, achieving the production of 3.8 g/L of mevalonate. Additionally, the abundant and recalcitrant polymer lignin is chemically decomposed into a formate-rich mixture of small organic acids and subsequently bioconverted into mevalonate. Overall, the described fast-growing, formatotrophic bioproduction strain demonstrates that a sustainable formate bioeconomy is within reach
Precursor reaction pathway leading to BiFeO 3 formation: insights from text-mining and chemical reaction network analyses
No full textWe integrated text-mined synthesis data with chemical reaction network analysis to reveal nitrite-bridging dimerization driving BiFeO 3 phase formation.
BiFeO 3 (BFO) is a next-generation non-toxic multiferroic material with applications in sensors, memory devices, and spintronics, where its crystallinity and crystal structure directly influence its functional properties. Designing sol–gel syntheses that result in phase-pure BFO remains a challenge due to the complex interactions between metal complexes in the precursor solution. Here, we combine text-mined data and chemical reaction network (CRN) analysis to obtain novel insight into BFO sol–gel precursor chemistry. We perform text-mining analysis of 340 synthesis recipes with the emphasis on phase-pure BFO and identify trends in the use of precursor materials, including that nitrates are the preferred metal salts, 2-methoxyethanol (2 ME) is the dominant solvent, and adding citric acid as a chelating agent frequently leads to phase-pure BFO. Our CRN analysis reveals that the thermodynamically favored reaction mechanism between bismuth nitrate and 2ME interaction involves partial solvation followed by dimerization, contradicting assumptions in previous literature. We suggest that further oligomerization, facilitated by nitrite ion bridging, is critical for achieving the pure BFO phase
Creating Home Away from Home: The Nepali Diaspora and Homemaking in the US
Get PDFThis research examines how members of the Nepali diaspora living in California have created their home environments using their transnational socio-cultural practices in the US to maintain their identity and well-being in this new context. The homemaking practices of members of the Nepali diaspora reflect the adaptive processes of creating their sense of self in the U.S. by addressing the spatial difficulties posed by performing their ethnic-specific socio-cultural activities within the context of U.S housing designs. Home is a significant site of cultural expression for various ethnic groups in Nepal, serving as a foundation for preserving their generational and family values, as well as sociocultural norms. The design of mass-produced houses in the U.S., built generally without the involvement of residents, mainly working and middle classes, poses a challenge for Nepali immigrants to continue their ethnic-based practices. It motivates them to invest in constructing a space with physical, socio-cultural, and emotional qualities to meet their daily needs.I use ethnographic, architectural, and participatory methods with ten households in Woodland, Davis, and Sacramento in Northern California to examine the design and layout of the different spaces in the home created by the Nepali diaspora, suitable to their everyday needs. The study explores the diasporic variations of Nepaliness by homeownership by examining tangible cultural markers such as food, artifacts, festivals, and the intangible socio-cultural values and meanings attached to the adjustment and modification of the physical spaces of the houses.By focusing on the connection between spatial processes and the meaning of the home, my research provides essential insights to improve the responsiveness of housing design to the needs and interests of immigrants and guide the process of customized housing design to make it more flexible and inclusive for diverse users. By highlighting the consequences of the missing link between residents and their homes, this research contributes to a dearth of literature on the cultural dimensions of domestic spaces in the US, broader architectural and socio-cultural understanding of US housing design, and less-studied aspects of the multidimensional user-created home environment. This research is grounded within the field of cultural geography and also draws insights from anthropology, sociology, and architecture, connecting the thematic areas of housing, migration, and culture. Deploying a multi-disciplinary approach helps to understand the active role of people in adapting and creating a physical and socio-cultural connection with their new homes. By bridging the intellectual domains of architecture and social sciences, the research contributes to a comprehensive understanding of the rich area of human-environment relationships, particularly in the context of human-centered design
Market Structure and Outcomes of Matching Markets
Get PDFThis dissertations focuses on why two-sided markets succeed and why they fail. In the first chapter, I examine the role of bilateral fit in the unraveling of markets, and find that in this context a small imbalance in the market can drive unraveling and lead to an allocation that is Pareto inefficient.
The second chapter defines a general class of preference distributions and then bounds the size of the core of a matching market with participants whose preferences are drawn from such a distribution. This technical result has important practical implications; anecdotal evidence suggests that centralized markets are far less likely to unravel when they are incentive-compatible or nearly so, and we know that two-sided markets can be incentive-compatible only if the core is a singleton. This chapter is an early step in a longer project of mapping out the potential space of preference structures to understand which markets are good candidates for centralization.
In the third chapter I extend this broader theme with a dynamic two-sided matching market model. In this work in progress I adapt a Diamond-Mortensen-Pissarides labor market framework and I find that with variable fits and a small imbalance between the sizes of the two sides of the market, an improvement in the matching technology can produce large welfare gains that accrue almost exclusively to one side of the market
Variance Components Estimation under High-dimensional Linear Models
No full textEstimation of signal-to-noise ratios (SNR) and residual variances in high-dimensional linear models has numerous important applications, including selecting tuning parameters for predictive models and estimating heritability in genomics. This dissertation investigates the consistency and asymptotic distribution of two widely used SNR estimators under various model assumptions.Chapter 2 presents my work, supervised by Professor Xiaodong Li, in which we study the restricted maximum likelihood (REML) estimator based on the likelihood formulation of the random effects model. Although the true model assumes an i.i.d. Gaussian priors for both the regression coefficients and the noise variables, we establish consistency and asymptotic normality of the REML estimator under model misspecification, where the true coefficient vector is fixed and noise components may be heterogeneous. In particular, the resulting asymptotic variance has a tractable form, allowing standard error estimation via a measure of noise heterogeneity.Chapter 3 discusses my joint work with Zhentao Li and Professor Xiaodong Li. While the method-of-moments estimator is commonly used in SNR estimation in single-response settings, we extend this framework to multivariate linear models under both fixed and random effects formulations. In this study, we establish and compare the asymptotic distributions of the proposed estimators. Furthermore, we extend our approach to accommodate cases with residual heteroskedasticity and derive asymptotic inference procedures based on standard error estimation.In both Chapter 2 and Chapter 3, we validate our theoretical results through extensive numerical simulations. Further discussions and directions for future work are provided in Chapter 4
Mechanisms and Mitigation of Agricultural Soil Emissions in California: A Focus on Nitrous Oxide (N2O) and Nitrogen Oxides (NOx)
No full textCalifornia, a major supplier of fruits, nuts, and vegetables to the U.S., produces over 400 agricultural commodities. Its cropland soils are responsible for approximately half of the state's nitrous oxide (N2O) emissions, as well as a smaller yet significant portion of nitrogen oxide (NOx) emissions. As California works to meet the greenhouse gas (GHG) emission targets set by AB 32 beyond 2020, it must also address the new EPA regulations concerning particulate matter (PM2.5) pollution in its agriculturally intensive areas, which is largely caused by nitrogen oxide (NOx) emissions. This dissertation aims to improve the understanding of the complex processes and environmental factors that contribute to nitrogen gas losses in agriculture. Chapter 2 presents a controlled experiment examining the dynamics of N2O consumption and the potential of highly organic peat soils to act as sinks for N2O under varying water content conditions. This study examines the impact of soil water content and carbon levels on N2O consumption. The results indicated that maximum consumption occurred at moderate soil moisture levels (50–75% water-holding capacity). These findings confirm the possibility of using managed water tables, particularly in rice farming within the Sacramento-San Joaquin Valley, to enhance soil N2O consumption. Chapter 3 serves as a methodological and integrative bridge between the experimental findings on N2O consumption presented in Chapter 2 and the broader goal of improving predictions of these emissions. This chapter develops a quantitative model of N2O consumption rates, calibrated to experimental data, to inform future emission models. Chapter 4 synthesizes NOx field flux data across California's cropping systems, evaluating how cropping systems, soil texture, management practices, and climate factors influence emission patterns. Significant variability in emissions was documented, primarily influenced by crop type and soil texture. Crops with higher nitrogen inputs, such as silage corn and tomatoes, exhibited higher emissions. Soil texture also affected NOx fluxes differently, with the highest observed emissions coming from clay and sandy loam soils. The analysis highlighted management strategies as critical control points for mitigating NOx emissions. Correlation analyses revealed overlapping microbial pathways responsible for both NOx and N2O emissions, which were particularly intensified by irrigation-induced cycles of drying and wetting
Fish Conservation in Mediterranean Ecosystems: Ecological Insights for Sustainable Management
Get PDFHealthy fish populations are an essential part of functional aquatic ecosystems which provide society and the environment with a multitude of benefits. However, after centuries of increasing habitat degradation and resource overexploitation, they are among the most imperiled on the planet. This is especially true for populations located in Mediterranean climates, where environmental needs must compete for the seasonally limited water supply with agricultural and urban use. Additionally, while native Mediterranean flora and fauna are adapted to the unique patterns of heavy rainfall in the winter followed by long dry summers, projected intensification of extreme weather events such as droughts and floods coupled with increased average air temperatures and decreased average precipitation pose a major threat. Natural resource managers are tasked with finding novel ways of sustainably managing aquatic ecosystems, yet basic knowledge on the relationships between fish and their environments is frequently lacking. For example, while the Central Mediterranean region of Chile supports a highly endemic and vulnerable assemblage of freshwater fishes, research on these species is still relatively scarce. Additionally, given the current and projected threats to California’s aquatic ecosystems and fisheries, a deeper understanding of how these resources function could greatly contribute to long-term conservation efforts.The aim of this dissertation is to provide research that increases our understanding of how fish distribution and behavior are impacted by their environment, and how this knowledge can inform effective and sustainable conservation management. My dissertation focuses on several aspects of fisheries research and management, ranging from single-species behavior and movement to broader patterns in community ecology. Across all chapters, I explicitly consider how both human and environmental factors shape ecological responses. This work centers on case studies from two Mediterranean climate regions: the central valleys of Chile and California, as these ecosystems are especially threatened by current and future anthropogenic disturbances.In Chapter 1, I apply multi-species occupancy models to predict species richness and individual species occupancy in the data-limited systems of Central Chile. These findings offer critical insights for conserving these rapidly declining ecosystems. Chapters 2 and 3 focus on the ecology and management of sturgeon in California. Chapter 2 synthesizes current knowledge of the biological, ecological, and societal factors influencing Green and White Sturgeon management and identifies strategies that could support their conservation in California. Chapter 3 explores how the river flow regime impacts adult Southern Distinct Population Segment (sDPS) Green Sturgeon (Acipenser medirostris) spawning migration through the Sacramento-San Joaquin Delta, with implications for informing water management. Together, these chapters provide actionable information for fisheries and freshwater conservation, supporting sustainable management of Mediterranean river systems in a changing world
Head to Head: Politics and Multivalency in the Envoys Hall at Wawel Castle, Kraków
No full textEmbedded within the ceiling of the Envoys Hall at Wawel Castle in Kraków lies the Wawel Heads, a series of thirty polychrome human sculptures. Beloved Polish icons and the subject of numerous scholarly studies, these Wawel Heads have a prevailing status as an enigma, with most questions surrounding them focusing on their elusive subjective meaning. However, this thesis takes a new, spatial-functional approach to studying the heads, attempting to position the sculptures as active material agents that communicate early modern Polish identity. As the Envoys Hall functioned multivalently as a parliamentary chamber, throne room, and diplomatic reception hall, the Wawel Heads’ role similarly shifted: they acted as mediators in power struggles between the monarchy and nobility, as symbolic assertions of national unity before foreign envoys, and as protective talismans when the room stood empty. This thesis sets out to show that the Wawel Heads are more than a unique ornamental decoration and play a significant role in political negotiation within Polish history than previously established