University of Massachusetts Boston
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Sexual Development in the Blue Mussel, Mytilus Edulis: An Emphasis on Feminization and Other Disruptions
No full textSex determination and differentiation in metazoans are dynamic processes involving genetic and environmental factors. Both of these processes are tightly linked where sex determination directly informs sex differentiation. Though Mollusca is the second most diverse animal phylum, behind Arthropoda, sex differentiation is understudied in this group, especially bivalves. Greater foundational research into bivalve sex differentiation is required to understand the complexity of this process and the ways outside forces, such as xenobiotics and parasites, may perturb sex differentiation. The purpose of this research is to identify and characterize sex differentiating genes in the blue mussel, Mytilus edulis, and disruptions to the male/female phenotypes. A phylotranscriptomics approach identified putative sex differentiating genes across Bivalvia and characterized their sex-specific expression in M. edulis. Following, mussels were exposed to two endocrine disrupting compounds to induce a sex change. These compounds induced a sex reversal in some mussels and flipped expression of sex differentiating genes. Transcriptomic profiling using RNA-seq assessed the effects in mussel populations from polluted estuaries that are known to be experiencing endocrine disruption. The expression of putative sex differentiating genes and gonadal development were measured over an annual cycle to link these genes to sex differentiation. Finally, the effects of a parasitic trematode were determined in mussels, with particular emphasis on gonadal development. Overall, this research provides critical foundational research on bivalve sex differentiation and associated disruptions to this process
Essays on the Impacts of Climate Risk on Corporations
No full textThe three related essays in my dissertation focus on analyzing the impact of climate risk on firm-level risk, corporate innovation, and CEO decision making.
The first essay investigates how climate risk, proxied by exposure to major catastrophic climate events, impacts firm-level risk. Using the location of both corporate headquarters and affiliations, this paper finds a positive association between a firm\u27s exposure to abnormal extreme climate events and both idiosyncratic risk and systematic volatility. These effects are stronger on companies that are more geographically dispersed, more diversified, or operate in an industry with more environmental issues that are considered financially material according to the SASB (Sustainability Accounting Standards Board). Additionally, the impacts are more substantial for events with greater investor awareness when the company is located in areas with stronger beliefs in climate change. Moreover, this effect is mitigated when companies have better environmental performance. Overall, our research contributes to a better understanding of businesses’ exposure to the risks associated with climate change.
The second essay studies whether catastrophic climate events spur environmental innovation in companies. Climate disasters are random events whose occurrence may influence managers’ risk perception. Using a new approach to classify environmental patents under the updated U.S. patent classification system and a difference-in-differences design, we show that when the headquarters of a company is exposed to a climate disaster event the number of environmental patent applications increases over the following three years. We also find that the market value of a company’s environmental patents increases after exposure to climate disasters. In addition, these effects are stronger for companies operating in industries with higher environmental materiality and when companies’ headquarters are in Democratic counties and are mitigated for firms experiencing financial distress.
The third essay studies whether climate disasters in the CEO’s hometown impact the firm’s environmental performance and corporate social responsibility. I argue that CEOs’ perceptions of climate risk are altered when a catastrophic hurricane strikes their hometown. My findings suggest that CEOs adjust their firm policies when their hometown experiences a climate disaster. Specifically, I find that environmentally irresponsible activities and CSR concerns decrease after hurricanes strike the CEO\u27s hometown, resulting in improved environmental performance. Consistent with the salience and availability heuristic theories, this effect is more pronounced when it is the first time the CEO’s hometown is hit by a hurricane and for CEOs with greater ability
Breathe In, Write Out: Examining the Impact of a Virtually Delivered Mindful Breathing Intervention on Elementary-Aged Students\u27 Written Expression and Academic Engagement
No full textWritten expression is a complex and critical skill that many students in the U.S. struggle to master (National Center for Education Statistics, 2012). Meanwhile, the COVID pandemic has expedited the need to find feasible interventions that support students writing in a virtual landscape (The National Association of School Psychologists, 2020). Brief, mindful breathing exercises may be one viable option for promoting the cognitive and behavioral mechanisms that are executed during the writing process (Minkos et al., 2018; Cornell et al., 2019). As such, the present study provided three elementary-aged students with the a virtual, after-school opportunity to practice mindful breathing and writing and examined the impact of this practice on students\u27 written expression and academic engagement behaviors, specifically. Two of the three students demonstrated improvements in writing quantity and quality, as well as academic engagement behaviors, when engaging in the mindful breathing exercise. Implications for future research on the integration of mindfulness and academic practices are discussed
Exploring the Conformational Space and Classification of Proteins Using Robotics-Based and Machine Learning Methods
No full textProteins are essential molecules in living organisms that perform a broad scope of functionalities, such as catalyzing biochemical reactions, providing structural support, and acting as signaling molecules. Understanding the structure and dynamics of proteins is crucial to elucidate their functions and develop therapies for various diseases. However, the conformational space of proteins is vast, and experimentally exploring it is challenging and time-consuming. Therefore, computational methods are becoming increasingly important for investigating protein conformational changes and dynamics. These methods are also subject to considerable limitations, which are discussed in this dissertation, alongside potential techniques to address them.
The goal of this Ph.D. research is to study the literature regarding protein conformational changes and develop efficient and effective methods to explore their conformational space, which is paramount to understanding how proteins function.
The first two projects focus on using Rapidly-exploring Random Trees (RRT) and Monte Carlo (MC) simulations to efficiently sample and explore the protein conformational space. In the first project, we propose a new RRT*-based search algorithm that outperforms previous methods in terms of exploration efficiency. We further improve the search by integrating rigidity analysis information into the exploration process to help guide the search toward more low-energy conformations. We use topological data analysis in the second project to gain insights into the shape of protein conformational spaces and develop more practical exploration strategies. These methods are demonstrated on several benchmark protein systems and show significant improvements over existing techniques. The final two projects explore new directions in using machine learning techniques to analyze protein conformations. In the third project, we concentrate on designing a method for classifying protein families based on learned compressed representations. We show that these compact representations, which we call fingerprints, capture the relevant features of protein families. In contrast, in the last project, we use Variational Autoencoders (VAE) to explore the conformational space of proteins on molecular dynamics simulation data. Together, this work significantly contributes to advancing our understanding of protein conformational dynamics and developing new tools for studying protein structure-function relationships
Investigating Gender and Racial Bias of a Universal Social-Emotional and Behavioral Screening Tool
No full textUniversal screening of social, emotional, and behavioral functioning of students requires an equitable and accurate measurement tool in order to identify concerns and provide appropriate tiered supports. This study examined the psychometric properties of a common social, emotional, and behavioral screening tool, the Behavior Intervention and Monitoring Assessment System, Second Edition (BIMAS-2) using item response theory. The measurement equivalence was assessed at the subscale and item-level across gender, racial/ethnic, and intersecting gender and racial/ethnic student groups. Specifically, male and female groups, as well as Hispanic, Black, White, Asian, and “Other” racial groups and consequent intersecting groups were compared using differential scale functioning and differential item functioning. Subscale-level scores were found to be equivalent across all student groups; however, individual items were identified as functioning differently across student groups ranging from small to large effect size differences. Results of scale-level equivalence indicate the BIMAS-2 scales may help teachers identify diverse students who require mental health and behavioral supports and refer for appropriate interventions. Utilizing this universal screening tool in schools may reduce disproportionate discipline and special education referrals. Implications for practitioners and researchers are discussed
Examining Pilipina/x/o American Liminality: A Case Study of Asian American Panethnicity
No full textAs a panethnic label, “Asian American” represents over 20 national origin groups as designated by the U.S. Census Bureau (Budiman & Ruiz, 2021). Although Pilipina/x/os are one of the largest Asian American groups in the United States, they have been misunderstood within Asian America due to their colonial history as well as East Asian hegemony. Asian American support structures in colleges and universities, such as Asian American cultural centers and Asian American studies programs, are designed to focus on the Asian American community, including Pilipina/x/o Americans. Research suggests, however, that they tend to privilege East Asian American groups.
In this study, I examined how Asian American Cultural Centers and Asian American Studies at two institutions support Pilipina/x/o American students, if at all. Conducting a multiple-site case study allowed me to understand the contexts of Garnet University (GU) and Violet University (VU) as sites for Asian American and Pilipina/x/o student support. Additionally, through this case study, I sought to understand how Pilipina/x/o American students experience Asian American support structures at these sites.
The nineteen participants in this study provided key insights into how Asian American support structures address the needs of Pilipina/x/o American students at GU and VU, and the general challenges faced by Asian Americans on college campuses. Specifically, I found that (1) Asian American was a complicated identity and concept for the participants to grapple with; (2) the impacts of East Asian hegemony on Pilipina/x/o Americans; (3) students saw Pilipina/x/o American Student Organizations as important informal sites for support; and (4) practitioners in AACCs expressed institutional challenges with supporting Asian American and Pilipina/x/o American students.
Ultimately, at the sites, Asian American support structures fostered both ethnic and panethnic identity development for Pilipina/x/o students. Based on my findings, Museus’s (2014) CECE model, Nadal’s (2004) PAID model, and literature on Pilipina/x/o American students in higher education, I propose the Pilipina/x/o Navigation of Asian American Panethnicity (PNAAP) framework. PNAAP outlines how precollege contexts, ethnic and racial identity development, and campus contexts influence how Pilipina/x/o Americans understand their connection to Asian American panethnicity. The dissertation concludes with implications for future research and practice
LSD1-Mediated Epigenetic Reprogramming Driving Prostate Cancer Progression
Get PDFProstate cancer (PCa) is a leading cause of cancer-related deaths in men worldwide. Alterations in epigenetic regulation of gene expression have emerged as key contributors to PCa development, treatment resistance and disease progression. My thesis focuses on investigating the role of lysine-specific demethylase 1 (LSD1), a critical histone modifier, in mediating epigenetic reprogramming that drives PCa progression. The dissertation comprises three projects that elucidate the mechanisms by which LSD1 can regulate PCa progression. The first project shows that LSD1 can activate the PI3K/AKT pathway in PCa cells independent of its well-established androgen receptor (AR) coactivator function. The study identifies the regulatory subunit of PI3K, p85, as a critical transcriptional target of LSD1 that mediates its effect on the PI3K/AKT pathway activation. The second project focuses on understanding the molecular mechanisms behind PCa lineage plasticity, specifically driven by the transition from FOXA1 to FOXA2, both of which are pioneer transcription factors. This study shows that FOXA2 binds to distinct classes of enhancers in multiple AR-null PCa models with different lineages and drives AP-1 reprogramming by functioning as a pioneer factor of JUN. This unique chromatin activity of FOXA2 is dependent on LSD1-mediated demethylation of FOXA2 protein. The third project highlights the role of SET domain containing lysine methyltransferase 7 (SETD7) as a transcriptional repressor in PCa by opposing LSD1 activity. The study shows that SETD7 directly methylates FOXA1 to inhibit its chromatin binding and negatively regulates the LSD1-FOXA1 oncogenic axis. Furthermore, loss of SETD7 expression in PCa can induce reprogramming of FOXA1. Taken together, our results demonstrate that LSD1/SETD7-mediated epigenetic reprogramming plays a critical role in driving PCa progression and suggest that targeting LSD1 may be a promising therapeutic strategy for the treatment of PCa. This dissertation provides new insights into the molecular mechanisms underlying PCa progression and highlights potential targets for future therapeutic interventions
Investigating the Sexual Consent Process for Plurisexual Individuals
No full textBackground: To date, there is no universally agreed-upon academic definition of sexual consent (SC; Beres, 2007). However, the conceptualization of SC is rooted in the definition of sexual violence, with SC considered to be the boundary violated in experiences of sexual assault (SA; Fenner, 2017). Individuals with a plurisexual (e.g., bisexual, pansexual, or queer) identity report a SA prevalence greater than individuals with any monosexual identity (i.e., gay, lesbian, or heterosexual). To date, the SC literature is overwhelmingly focused on heterosexual norms, with few studies specifically aimed at understanding SM individuals’ experiences. Taken together, the literature appears to indicate that plurisexual individuals are at greater risk for SA than monosexual individuals. Part of this increased risk for SA may be due to the strain of having to navigate SC with both same-gender and different-gender partners. To investigate this research question, I conducted a mixed-methods study to understand how plurisexual individuals describe navigating SC with same- and different-gender partners. Methods: I recruited 289 individuals aged 18-40 years old. All participants identified with a plurisexual identity and endorsed sexual experiences with, and attraction to, both masculine and feminine partners. Participants were recruited from college campus emails, social media, and email solicitations after finishing similar studies. All participants completed an anonymous cross-sectional online survey with a focus on identity, SC experiences, and SA history. A subset of eight individuals were interviewed to explore their experiences navigating sexual consent with both masculine and feminine partners. Qualitative analyses were conducted using a team-based approach and guided by the theory and methods of conventional content analysis. Results: Quantitative explorations were generally consistent with qualitative findings. For example, non-verbal SC communication was more common than verbal communication. When participants endorsed different behaviors with same-gender partners than different gendered partners, it was coded as a “script-shift.” For women, script-shifts were associated with lower reports of SA. In a final hierarchical regression, initiating non-verbal script-shift (b = -.204, t = -2.67, p = \u3c .01) was found to be associated with SA above and beyond gender, age, and number of male sexual partners predicting sexual assault, F(1,157) = 5.74, p = \u3c .001, R2 = .11. Qualitative interviews resulted in six themes, including the idea that mutuality communicates consent and interest, and nonverbal communication is more common in sexual encounters, but verbal SC communication is particularly valuable. Discussion: This study is a first step in understanding both the experiences of plurisexual SC, along with exploring the ways in which plurisexual individuals may navigate between queer and heteronormative sexual spaces. Finally, this study explored whether there were increased SA risks associated with different SC behaviors for plurisexual individuals
Clifford Group and Beyond: Theory and Applications in Quantum Information
No full textIn this thesis, we explore the mathematical properties of the Clifford group, a special subgroup of the unitary group, as well as the additional resources necessary to go beyond the Clifford group. Quantum computation restricted to Clifford circuits and stabilizer states -- i.e. those obtained by Clifford circuits on computational basis states -- can be entirely simulated classically. In fact, quantum advantage lies beyond the Clifford group: the injection of non-Clifford gates into Clifford circuits introduces a quantum resource called magic. Magic is crucial for the unique and distinctive properties of quantum states and serve as a fuel for quantum computation: without magic, a quantum computer cannot do anything that a classical computer cannot do. Beside providing a overview on the stabilizer formalism and the resource theory of magic, this thesis is mostly devoted to a detailed exploration of the mathematical tools behind the stabilizer world and aims to be a practical guide for readers seeking answers about the effectiveness of states in producing resources beyond the stabilizer resources. In particular, it offers a detailed review on the Haar measure over the Clifford group as well as its extension for t-doped Clifford circuits --- Clifford circuit doped with t non-Clifford gates. The thesis delves into the properties and characteristics of these measures, shedding light on their significance, implications and possible applications. This thesis includes both previously known results from existing literature and new, unpublished findings. The main novel contributions of this thesis are as follows. First, we largely improve the lower bound for \epsilon-approximate projective k-design obtained by adding non-Clifford gates to Clifford circuits. The best known bound scales as O(k^4\log^2k\log\epsilon^{-1}), while this thesis achieves O(k^2+\log\epsilon^{-1}) by utilizing Markov process tools and techniques. The second main result of this thesis is the proof of a Fannes-Audenaert type inequality for the resource theory of magic. Specifically, we demonstrate that the difference between stabilizer entropies cannot exceed the trace distance between states, up to a factor scaling only linearly with the number of qubits. This inequality has diverse applications in the field of quantum information, connecting stabilizer entropies and the distance between quantum states
Educational Language Policy for Multilingual Learners: Leveraging Policy’s Multiple Dimensions and Discourses
No full textMultilingual students in the United States have long been marginalized by not only the institution of education but also within the classrooms where they learn. This has been accomplished in part through the embodiment of English monolingual ideologies in policies enacted across such contexts and in how language and multilingual students are discursively represented. In Massachusetts, however, due to recent official policy changes, educators may now implement pluralist language policies that reflect and promote the language policies of the communities they serve. Using a mixed methods design, this research explores the ways policy has been developed and enacted within the shifting educational language policy landscape. It investigates how official, top-down language policies, such as those passed at the state and federal levels through legislation, interact with bottom-up policies enacted in schools and classrooms where students learn through multilingual media, attending to the various practices, processes, and tensions that coexist as lived policy. Moreover, drawing on this multidimensional approach, the study also identifies discourses about language that emerged within and across policy levels in Massachusetts to better understand how policies are contextually created, negotiated, and embodied to shape students’ experiences in school. Data included quantitative and qualitative survey data on the language and policy beliefs of educators throughout Massachusetts to uncover the ideologies comprising educational language policy among educators state-wide, as well as qualitative case study data reflecting the enactment of policies in a focal district. Findings expose the sociopolitical ideologies, practices, and processes of policy and inform policy and praxis