SCHOLARTalks

Regulation of mitochondrial complex I assembly in Drosophila melanogaster

Most cells in our body have a powerhouse, called the mitochondrion, that generates most of the energy we need in the form of a molecule called Adenosine 5’-triphosphate (ATP). Within the mitochondrion, there is a specific machinery called the oxidative phosphorylation (OXPHOS) system that directly makes ATP. The OXPHOS system has five sub-machineries, referred to as complex I to V. Each of the sub-machineries has a number of parts (called subunits) that must be assembled together in the right orientation for it to be functional. Human CI is composed of 45 subunits, 14 of which have counterparts that are found in all other organisms that have CI. These 14 subunits are called central or core subunits. The 31 remaining subunits, that usually display major variations between organisms, are called accessory subunits. Scientists can use very powerful microscopes to determine how these minuscule sub-machineries look. Microscopic images of CI from all organisms assessed to date reveal a boot-shaped structure, but with some differences in fine details that can influence the function of CI. I will show and describe the microscopic image of CI from fruit flies. Although fruit flies are relatively harmless as they feed on rotten fruits, its sibling strain, spotted wing drosophila (SWD), is a major pest for soft summer fresh fruits in America and Europe, leading to annual estimated losses of more than $500 million in the wine and berry industries in the United States. I will explain how features of CI that are specific to fruit flies and SWD may uncover novel regulatory mechanisms that can be exploited to generate new pesticides for SWD. Finally, I will describe how, under some human therapeutic situations, it could be advantageous to drive CI assembly using the fruit fly mechanism.

It Takes a Team: The Dynamic Neurological Basis of Working Memory

Consider the act of getting to work (when not working from home). Whether by foot, train, bus, or car, getting to work requires making a plan, and stitching together many smaller steps to carry out that plan. We regularly do this, all while processing a ton of information to understand how far along we are in the process, and to adapt our plan in the face of unexpected developments (road closure, sudden rain, etc.). And generally, we do this planning, navigating, and adapting so seamlessly that we “don’t even think” about it.

But what’s going on here? How are we able to accomplish such a myriad of activities that require this level of planning and adaptable execution, especially in an increasingly (or evolvingly) distracting world?

I study behavior through the lens of working memory (WM), which is the capacity to hold things “in mind” for short periods of time to accomplish our goals. Even beyond spatial navigation, we use WM often: while preparing a meal; while writing an email; while learning a new dance move. Despite its cruciality to our day-to-day lives, however, WM is not fully understood, especially neurologically. My thesis project helps shed some light on the ways in which our brains dynamically enable us to use WM to make a plan, start implementing it, and adapt it on the fly, all while resisting distractions. Hopefully my presenting it will remind attendees of the majesty of our fundamental cognitive capacities, even if it doesn’t help them get to work on time.

“The Work Which Becomes a New Genre Itself”: A Case Study of Black Representations and Interactions within Contemporary Japanese Anime

The themes with which contemporary anime are concerned have globalized meteorically, addressing issues extending both within and far beyond Japan’s borders, and cementing anime as a form of cross-cultural communication that occurs on an international scale. Current literature that addresses representation of foreigners in Japanese pop culture, while extremely crucial and enlightening, tends to focus on literary media including manga (Japanese comics) but rarely on anime. When they do focus on anime, analysis of foreign representations almost never take into account Black foreigners, instead focusing primarily on representations of white Europeans or Americans, and they often fail to seriously take into account fans’ reception of these representations. Nevertheless, the relationship between anime and Blackness, and that between anime and its Black fans, is incredibly complex and multifaceted. Uncovering and highlighting this complexity, while also reintegrating Black fans into the historiographical narratives of the anime industry within the United States, this paper begins to fill gaps regarding the understanding of Otherness as represented in anime.

Through close readings of anime productions featuring Black protagonists, Black supporting characters, and no explicitly Black characters at all, this paper traces the ways in which difference has been received, morphed, and then disseminated through anime, elucidating several factors that allow Black fans to see themselves in anime and to thus form a significant facet of American anime fandom even when Black representation is not explicitly visible, or when it takes on offensive tones. By examining existing oral histories, interviews with Black fans of anime, and media representations of Blackness as well as Otherness in anime, the paper demonstrates that anime has had a clear, significant and real impact on Black fans; moreover, Blackness and Black fans themselves have also had a clear, significant, and real impact on the Japanese anime industry.

Engaging Adolescents and Young Adults to Develop a Digital HIV Stigma Reduction Intervention Using Crowdsourcing

This presentation will focus on the use of crowdsourcing methods among adolescents and young adults in Kazakhstan to develop culturally- and age-tailored digital intervention content to reduce HIV stigma and increase HIV self-testing as part of the JasSpark study. Procedures of the crowdsourcing contest will be discussed and winning results presented.

African American Language in Large Language Models

Machine learning models for tasks like automatically detecting hate speech or identifying the language of text have been shown to struggle with African American Language or AAL. As a dialect of English with over 30 million speakers, AAL follows consistent grammar and syntax rules distinct from mainstream English, leading many models to be unfamiliar with its unique features. Little is known, however, about the dialectal biases of models capable of generating language. Such large models like ChatGPT are the largest and most capable models available, and therefore, investigating their potential biases is necessary to ensure they equally benefit and avoid negatively impacting African Americans. Toward this aim, we perform a detailed analysis of multiple large language models’ performance on three varieties of English: African American Language, Social Media Language, and Privileged White English. Models are evaluated with three language generation tasks, including rewriting the text of one variety into another, predicting phrases that are left blank in input texts, and generating a dialogue response given past conversation turns. Using these tasks, we examine performance gaps between varieties of English to identify potential biases in each model. In preliminary experiments, we find that large language models perform worse with both African American Language and Social Media Language compared to Privileged White English, particularly with specific features such as aspectual verbs (the habitual “be” as in “he be walking”). A case study of the current most popular chatbot, ChatGPT, shows similarly strong preferences for formal English inputs. Additionally, beyond the impacts of biased language models, we discuss the ethical implications of language models that can understand African American Language and other varieties of English, such as increased police surveillance of minority populations.

Zebras, Horses, Diversity and Biology

Prof. Thaker’s research is focused on the genetic causes of early onset severe weight gain in children and adults. Her lab aims to identify novel genetic causes of excessive weight gain, with a special focus on children from diverse backgrounds. In their clinical/translational study, they recruit individuals with severe early onset obesity for genetic investigations, Additionally, they are studying a rare condition called ROHHAD (rapid onset obesity, hypothalamic dysregulation, hypoventilation and autonomic dysfunction) syndrome, where children have severe weight gain early in life and a variety of other issues. They have prioritized a few novel genes that may have a role in weight regulation from these studies. The term zebras is used to indicate rare genetic conditions. e.g. horses are all children with obesity and zebra is a person with genetic cause of obesity (~ 5%). Because genetics differs in diverse populations, it can inform us about biology.

Contribution of Blood Components to Cell Death in ACL Injury Through Ferroptotic Mechanisms

In the United States, there are approximately 250,000 anterior cruciate ligament (ACL) ruptures per year. ACL injury is typically accompanied by joint bleeding in the knee and leads to osteoarthritis. Hemarthrosis or articular bleeding has been shown to induce joint inflammation and has been implicated in fibrosis of the synovium and degeneration of cartilage. Additionally, iron homeostasis is vital to joint health as excess iron content can lead to oxidative stress damage which is closely associated with osteoarthritis and hemophilic arthropathy. It has been shown that overproduction of reactive oxygen species and acute blood exposure can lead to cellular damage and increases in pro-inflammatory cytokines. Short-term exposure to supraphysiologic blood concentrations in articular cartilage is known to be damaging and similar detrimental effects can be seen in the ACL. Here, we analyze the effect of blood exposure on the ACL in the context of a specific type of cell death characterized by iron dependency and oxidative stress, ferroptosis. We hypothesized that ACL fibroblasts after acute short-term blood exposure will exhibit lower rates of cellular migration in a wound healing model and increased forms of cell death including ferroptosis. Understanding the role that ferroptosis plays in blood-induced cell death can lead to targeted therapies that directly address the wound healing process. Further exploring the early events in ACL injury that may lead to poor primary repair outcomes provides new knowledge that may be used to optimize clinical intervention of intra-articular bleeding in ACL treatment.

Culture Fit System: How to Measure and Manage Culture through Employee Selection

Many organizations use formal systems to measure and manage organizational culture. Using proprietary data from a highly-decentralized organization, I examine the employee performance consequences of adopting a formal culture-fit measurement system in employee selection. I exploit the staggered feature of the adoption of the system, and find that employees selected with the system perform significantly better than those without the system. However, the performance consequences of adopting the culture-fit measurement system exhibit significant variation depending on (1) alignment of existing local culture and organizational values, and (2) noise in the measurement of culture-fit due to applicants’ gaming behavior (i.e., applicants may game the system by pretending to be culture-fit). Taken together, this study implies that the adoption of a formal culture-fit measurement system can potentially alleviate difficulties in instilling organizational values and highlights the conditions under which such a system can be more effective in facilitating the diffusion of organizational culture.