Category: 2022

On the Multifractal Structure of Observed Internet Addresses

Presenter: Megan Walter – Computer and Information Science

Faculty Mentor(s): Reza Rejaie, Chris Misa

Session: (Virtual) Oral Panel—Inner Space and Internet

As a result of society’s increasing dependence on the internet, we observe an uptick in internet attacks and network management issues. However, the growing speed and volume of internet traffic makes finding portions of traffic responsible for creating problems difficult. Current approaches to classifying connections as harmful or benign tend to regard each connection independently of one another. However, the nature of IP addresses points to correlations between addresses located in similar parts of the IP address space. Understanding the structural characteristics of the IP address space could lead to novel ways to create network management algorithms that deal with aggregates of flows.

We examine the structure of observed IP addresses in network traffic collected from border routers at the University of Oregon. Previous work indicates that the characteristics of observed IPv4 address structures are consistent with a multifractal model. We work to solidify the existence of this multifractal structure and provide an initial contribution to the development of network security and management solutions that aggregate flows by IP address. We use a brand new method of multifractal analysis using the method of moments to produce an initial characterization of how observed IPv4 addresses relate to one another. We applied this process across traffic samples representing three different timescales, allowing us to look at the temporal dynamics of these multifractal characteristics.

Exploring the Effect of Social Media Popularity Metrics on Curiosity

Presenter: Erica Waldron – Psychology, Sociology

Faculty Mentor(s): Dare Baldwin

Session: (In-Person) Poster Presentation

Social media inundates us with information about popularity; for example, social media posts are accompanied by a number of likes and comments. Dubey and colleagues (2020) recently demonstrated that such indicators of popularity influence people’s curiosity to learn more about specific topics. If so, this is one unexpected, beneficial side effect of social media popularity metrics. However, the way in which they manipulated popularity via Reddit-like “upvotes” may have introduced a confound into their findings. In particular, people were asked to report about an item’s popularity immediately before reporting on their curiosity regarding that item. The immediate juxtaposition of these two questions may have led participants to assume that popularity was relevant to curiosity, thereby creating what is called a demand characteristic that contaminated their findings. My thesis research attempts to replicate Dubey and colleagues’ research while avoiding this potential demand characteristic. People rated curiosity first and were asked about popularity only at the end of the survey. Analyses on preliminary findings modeled after Dubey et al. suggest that their findings are not replicating. That is, people are no more curious about items with a high number of upvotes than those with a low number of upvotes. To the extent that my full data set is consistent with this non-replication, these new findings bring into question whether popularity has any relationship to curiosity.

Geometric and Thermal Constraints on the Timing of Alaskan Tidewater Glacier Retreat

Presenter: Lucy Waghorn – Earth Sciences

Faculty Mentor(s): Dave Sutherland, Alex Hager

Session: (In-Person) Poster Presentation

Glaciers around the world are retreating at increasing rates, prompting concerns over sea level rise and the future of the cryosphere. In southern Alaska, some have retreated while their neighbors have advanced, indicating that local atmospheric conditions are not the only influence on glacial retreat. One possible factor is the interaction of ocean water with the glacier at the terminus. However, fjord geometry can alter the ocean water that interacts with the terminus, and the interaction of fjord geometry and ocean temperature anomalies has not been investigated in Alaska thus far. To investigate the interaction of fjord geometry and glacier retreat, we used bathymetry, air temperature (AT), sea surface temperature (SST), and terminus position data. Here we show that high SST anomalies may enhance glacial retreat in fjords with shallow sills. During a high SST anomaly, some glaciers in shallow-silled fjords retreated rapidly from a point of relative stability. Many glaciers also showed enhanced retreat in the two years after a high AT anomaly. It is possible that shallow sills influence fjord water circulation where only the warmest part of the water column can enter the near terminus region, potentially leading to enhanced glacier retreat after high SST anomalies. Though other factors can also contribute, understanding these processes and interactions that lead to glacier retreat is becoming increasingly important as climate change alters the atmosphere and environment.

Food Security Among University of Oregon Students During the COVID-19 Pandemic

Presenter: Jennifer Vuong – Family and Human Services, Psychology

Faculty Mentor(s): Dr. Elizabeth Budd

Session: (In-Person) Oral Panel—Covering Covid

U.S college students are vulnerable to low food security and students of color more so than White students. Those with low food security tend to consume fewer daily servings of fruits and vegetables. Low food security and lower fruit and vegetable intake are associated with poor health outcomes. Food security and eating behaviors of University of Oregon (UO) students during the pandemic are unknown. This study examines the food security and eating behaviors of UO students, whether food security varies by race and ethnicity, and how fruit and vegetable intake may vary by students’ income level, student status, and use of food assistance programs. From August-October 2020, 779 UO students completed a Qualtrics survey. One-way ANOVAs were conducted. In Fall 2020, 47.2% of UO students reported low food security. Black/African American students experienced low food security at higher rates than White students (p = .045). Fruit and vegetable intake significantly varied by income (p = .001; p = .001) and student status (p = .01; p = <.001). Only vegetable intake significantly varied by use of food assistance programs (p =.04). Concerningly, low food security is common among UO students and more common among Black/African American students. Also, undergraduates and lower-income students consume fewer fruits and vegetables than other students. Findings can inform programs to support food security and healthy eating.

Utilizing real time strain to modulate patient-specific rehabilitation optimizing bone recovery

Presenter: Alyssa Vongphachanh – Human Physiology

Co-Presenter(s): Walker Rosenthal

Faculty Mentor(s): Kylie Nash

Session: (In-Person) Poster Presentation

Severe bone injuries often result in high complication rates and poor functional recovery. Mechanical loading through rehabilitation is a longstanding treatment for these injuries, but current practices are still challenged with variable healing, limiting this promising therapeutic [1,2]. Recent advancements in implantable strain sensors may promote better understanding of how rehabilitation induced loads contribute to healing outcomes [1]. Our lab uses this idea in a rat femoral segmental model stabilized with an internal fixation plate embedded with an implantable strain sensor to analyze the mechanical environment throughout healing for different loading conditions. Past work has found that load-sharing (compliant) fixation devices exhibited improved healing outcomes when compared to load-shielding (non-compliant) fixation plates [3]. We investigated the effects of rehabilitation on bone volume by using a wireless compliant fixation device capable of acquiring real-time micro-strain measurements on a segmental defect in the femur. We found that bone union occurred in 3/3 rehabilitated rats and only 2/4 in non-rehabilitated, sedentary counterparts. Rehabilitated rats experienced a higher mean strain amplitude and their bones bridged earlier than their sedentary counterparts. Our findings suggest a relationship between strain and bone healing outcomes. We hope to further explore the effects of rehabilitation intensity on local defect strain and thus bone healing outcomes.

Installation and Preliminary Use of Lunt Solar Telescope at Pine Mountain Observatory

Presenter: Nico Tuton-Filson – Physics

Co-Presenter(s): Jackson Robinson

Faculty Mentor(s): Scott Fisher

Session: (In-Person) Poster Presentation

Pine Mountain Observatory (PMO) has been operated by the University of Oregon for many years, recently expanding with new fields of observation, such as solar observation. Through our partnership with the Allan Price Science Commons & Research Library, our lab acquired a solar telescope in early 2021. This is the first solar telescope to be installed at the observatory, and therefore our lab team is learning how to best utilize this new equipment. Our end goal is to capture live images of solar activity and share them online in real-time. Through independent research and preliminary data collection, we have worked towards finding the optimal procedure for capturing and processing images. By the end of the summer 2022 we will be finalizing the installation and automation of the telescope and its image processing system. This work is vital to the University because it will create new research opportunities for future undergraduate students and provide an online resource to be used in classrooms at UO and beyond.

Effects of Rangeland Compost Amendments on Nematode Abundance

Presenter: Maya Treder – General Science

Faculty Mentor(s): Ashley Shaw, Lauren Hallett

Session: (In-Person) Oral Panel—Fuel, Fire, Grass and Compost, Poster Presentation

California rangelands are often over-grazed, nutrient-depleted, and subject to variable rainfall. Compost amendments are gaining popularity as a management tool due to their potential for soil carbon sequestration. Despite positive effects on plant growth, little is known about how soil communities respond to these amendments, especially across variable precipitation conditions. Nematodes are excellent indicators of soil community responses as they span every trophic level and are sensitive to changing environments. Here, we examined how amendment treatments (compost, fertilizer, none) affect nematode communities across variable precipitation conditions (drought, irrigation, wet). We hypothesized: 1) amendments increase nematode abundance, where compost has a greater positive effect than fertilizer; 2) nematodes respond positively to elevated soil moisture and negatively to drought; 3) effects of amendment and precipitation are interactive, where compost mitigates drought’s effects on nematodes. As expected, compost increased nematode abundance relative to other amendment treatments. However, overall, nematodes were most abundant under ambient precipitation, contrary to expectations. This was due to the precipitation-amendment interaction. While compost and fertilizer had similar positive effects on nematodes under ambient and irrigation, under drought, fertilizer had a negative while compost had a positive effect on nematode abundance compared to the no amendment treatment.

Stories of Decline: Narratives and Risk Framing of Glacier Retreat and Salmon in Washington, USA

Presenter: Jenna Travers – Marine Biology

Faculty Mentor(s): Mark Carey

Session: (In-Person) Oral Panel—Learning from the Environment

Climate change is threatening both glaciers and salmon in Washington with extinction, putting the state’s economy, culture, and ecosystems at risk. However, the overlapping crises are framed and understood differently throughout the state, affecting policy and climate action. This study analyzed 115 media sources from four main stakeholder categories to determine a) which narratives of glacier retreat and salmon declines are the most prevalent; b) how perceived risks change among stakeholders and cause narratives to diverge; c) how these narratives are shaped by stakeholder identity, geographic location, knowledge sources, and time; and d) how narratives of overlapping climate emergencies differ from narratives of a single crisis. Key narratives were identified by creating a qualitative codebook that was applied using Dedoose, and the presence of narratives was analyzed across the categories to evaluate trends. The study found that while a common narrative did exist, stakeholder identity, geographic location, and source of knowledge were all key factors in shaping narratives. It also found that narratives of overlapping climate emergencies were more likely to diverge than those of a single crisis. As climate change worsens and causes more overlapping crises, understanding how climate narratives are created and shaped will become increasingly important for understanding stakeholder conflicts, effective climate campaigns, and how people view themselves within these crises.

Molecular Dissection of the SHIP1 Phosphatase

Presenter: Pilar Tosio – Psychology

Faculty Mentor(s): Grace Waddell

Session: (In-Person) Poster Presentation

The 145 kDa lipid phosphatase SHIP1 is a critical component in immune cell signaling pathways and allows hematopoietic cells to undergo chemotaxis. Although the enzymatic role that SHIP1 plays in the dephosphorylation of phosphatidylinositol-3,4,5-phosphate (PI(3,4,5)P) lipids is understood, much remains unknown about the role SHIP1 plays in the excitable signaling network. Using TIRF microscopy, we can observe SHIP1 being recruited to the plasma membrane where the protein can be activated and inactivated. How this lipid phosphatase is being localized to the plasma membrane is not yet understood. We hypothesized that the region responsible for SHIP1 localization exists within the SHIP1 C-terminus. By performing a molecular dissection of the SHIP1 phosphatase, we determined that the last 110 amino acids of SHIP1’s C-terminus is required for SHIP1 to display polarized membrane localization patterns in human neutrophils. This finding has helped to elucidate the biochemical underpinnings of immune cell migratory functions.

Exploring the Role of the Arp2 D-Loop in Activation of Arp2/3 Complex

Presenter: Maisie Topping – Biochemistry

Faculty Mentor(s): Brad Nolen, Heidy Narvaez Ortiz

Session: (In-Person) Poster Presentation

Branched networks in the actin cytoskeleton are critical for a variety of cellular processes including endocytosis. New branched actin filaments are nucleated by Arp2/3 complex, and the deregulation of this protein is related to diseases such as cancer. Arp2/3 complex is intrinsically inactive. During activation, the complex undergoes a conformational change that brings two of its subunits, the actin-related proteins Arp2 and Arp3, into a position that mimics two consecutive actin subunits within a filament, thereby creating a template for the new filament. When actin polymerizes into filaments, a portion of the protein called the D-loop helps to stabilize the filamentous structure, and the Arp2 and Arp3 subunits both contain a similar D-loop. A previously solved structure of Arp2/3 complex at a branch junction indicates that a contact between the D-loop of Arp2 and ArpC3 may be important for stabilizing the activated complex at the junction site. This project aimed to assess the importance of that contact in activation of Arp2/3 complex. We generated a strain of budding yeast with three mutations in the Arp2 D-loop, purified Arp2/3 complex from cells, and used pyrene actin polymerization assays to test the ability of the mutated complex to nucleate actin filaments compared to the wild type. The Arp2 triple mutant showed greatly decreased activity, indicating that the contacts between Arp2 and ArpC3 are important for the activation and function of Arp2/3 complex.