Tag: Poster 48

(Re)generative Process and the Edible City: Ecological Urbanism in Portland, Oregon

Presenter: Jack Thomas

Mentor: Hajo Neis

PM Poster Presentation

Poster 48

The modern city archetype is undergoing drastic change as urbanists and laypeople alike begin pulling the landscape into the world’s urban areas, which have in essence, become “edible”. Agriculture has undoubtedly shaped the city of Portland, Oregon as the landscape beyond its UGB trickles into the city fabric. Urban farms, sidewalk gardens, and everything in between have popped up throughout the city, offering plant education, social rehabilitation, community interaction, food security, and personal health, among other benefits. With different goals and values, Portland’s urban agriculture movement is varied in its intent, yet equal in its significance to a changing urban morphology derived from patterns and occurrences happening within the city limits. In better understanding Portland as a model for how notions of ecological urbanism have been applied both top-down and bottom-up, these discoveries can potentially be applied throughout the world, guiding urban growth and community development that is environmentally sustainable and conducive to both social and physical well-being. Through interviews, precedents, visual analysis, and a theoretical long-term plan for urban agriculture in Portland, a holistic understanding of the city as a complex structure of linked urban patterns can be made. The “Edible City” of Portland can be presented as a model of (re)generative process and ecological urbanism which might have the potential to catalyze in other urban scenarios.

Fossil Eulipotyphla from Oregon’s Middle Miocene: New Occurrences and Biogeographic Patterns

Presenter: Danielle Oberg

Mentors: Samantha Hopkins and Edward Davis, Geology

Poster: 48

Major: Geology 

Insectivores (euliptophylans) are not well understood in the Miocene of Oregon. Recent discoveries from a new locality, Cave Basin, in the John Day Formation suggest a greater diversity of insectivores than was previously known. Early Miocene records are extremely poor and lack small mammals entirely. However, the Middle and Late Miocene explode with new families never seen before in southern Oregon. The Middle Miocene has the greatest insectivore diversity with occurrences of ancient shrews (heterosoricidae), red-toothed shrews (soricidae), true moles (talpidae), and hedgehogs (erinaceidae) clustering around the Oregon-California border in southeastern Oregon. Fourteen Middle Miocene localities have red-toothed shrews and true moles, while hedgehogs and ancient shrews are found in two localities. Diversity rapidly decreases for ancient shrews and hedgehogs throughout the Late Miocene and into the Clarendonian, but remains relatively constant for true moles and red-toothed shrews. Red-toothed shrew Late Miocene localities are further south and less clustered than Middle Miocene ones. True mole localities have a greater spread across eastern Oregon, ranging from the Oregon-Washington state line to the southern corner of Oregon. These new discoveries in the Oregon Miocene are a significant addition to the understanding of the Oregon fossil record. Furthermore, these insectivores reveal new insight into the paleoecology of the Miocene, changes in diversity over time, and evolution of insectivores that are still found in Oregon today.

Water Flux in a Mangrove Forest

Presenter: Katalin Plummer

Co-Presenters: Alyssa Bjorkquist

Faculty Mentor: Richard Emlet, Jan Hodder

Presentation Type: Poster 48

Primary Research Area: Science

Major: Marine Biology, Spanish

Water flux plays an important role in structuring and maintaining biodiversity in aquatic environments, such as tropical mangrove forests where lower water flux could reduce organic carbon outflow so that critical nutrients are more available for regulating organismal trophic processes. In the present study, we used two dissolution methods to estimate water flux at two mangrove sites within Bocas del Toro, Panama. We investigated how water flux differs with respect to mobility of a substratum (mobile versus stationary) as well as its position within a mangrove forest (exterior versus interior). We also examined organic carbon content of the sediment of each site in relation to water flux activity to ascertain the existence of a correlation between water flux and nutrient cycling in these environments.

Water flux differed significantly between sites for both the long-term and short-term (p < 0.001, both) dissolution trials. Additionally, we found a significant difference in sediment carbon content between sites (p < 0.01). While the two sites differed significantly from one another overall, these results do not suggest that water flux alone significantly affects marine community composition within a mangrove forest. We speculate that outside abiotic or geographic factors also influence physical conditions of these communities. Studying the intersection of biological and physical factors within mangrove forests may inform future research and conservation efforts pertaining to these environmentally sensitive habitats.

Investigating the Role of EZH2 in Heart Development

Presenter(s): Diana Nguyen − Biology, Human Physiology

Faculty Mentor(s): Gabriel Yette, Kryn Stankunas

Poster 48

Research Area: Genetics, Heart Development, Biology

Funding: O’Day Fellowship in Biological Sciences and the Office of the Vice President for Research and Innovation

Nearly 1% of individuals are born with a congenital heart defect (CHD), making CHDs the most common birth defect. Understanding the genetic and epigenetic underpinnings of heart development has the potential to aid in developing tools to diagnose and treat CHD. It is increasingly evident that chromatin structure and histone modifications play essentiaL roles in heart development and homeostasis. A histone modification of interest is the tri-methylation of lysine 27 of histone H3 (H3K27me3), which is associated with gene repression. This modification is catalyzed by EZH2, the methyltransferase component of Polycomb Repressive Complex 2 (PRC2), and can be removed by Kdm6 family of demethylases. Recent work in the Stankunas lab shows that disruption of Kdm6ba and Kdm6bb in zebrafish result in smaller, poorly trabeculated ventricles of the heart. Interestingly, hearts of mice with Cre/lox dependent knockdown of Ezh2 exhibit hyper-trabeculation, ventricular septation, thinning of the ventricular wall, and aberrant skeletal muscle gene activation. These studies highlight the proper maintenance of H3K27me3 necessary for proper development. Yet, the effects of EZH2 on heart development in zebrafish has not been well explored. Zebrafish are ideal for investigating the early stages of heart development since they are transparent, and develop outside the mother, allowing for easy observation of the heart during this crucial period; elements that evades the Cre/lox system in mice. We generated an ezh2-null allele allowing us to conduct heart development studies. We hypothesize that PRC2/EZH2 is necessary to establish and maintain cardiomyocyte cellular identity by repressing developmental pathways of similar tissue types. For this project, we aim to: 1) Establish when and where EZH2 is expressed in the heart during development, and 2) Determine morphological and functional changes in developing hearts of ezh2 null zebrafish.

The Likelihood of Eliciting Motor Evoked Potentials with Paired Pulse TMS

Presenter(s): Ethan Kizziar

Faculty Mentor(s): Ian Greenhouse

Poster 48

Session: Sciences

The excitability of the corticospinal pathway changes in a dynamic manner. Here, we used paired-pulse transcranial magnetic stimulation (ppTMS) to test the hypothesis that rapid changes within motor cortex determine the likelihood the corticospinal pathway will become active. In six participants, pairs of electromagnetic pulses separated by 3ms were administered over primary motor cortex to induce a twitch, or motor evoked potential (MEP), in a target finger muscle. The first ‘conditioning’ pulse was changed dynamically to a percentage of a subject’s active motor threshold (AMT, the minimum TMS intensity to consistently elicit MEPs during a mild tonic contraction). The second ‘test’ pulse, produced the MEP. Using electromyography to record muscle electrical activity, we calculated MEP sizes of the course of 100 measurements, with 20 measurements at each 5 conditioning pulse intensities.

We observed a recurring pattern of an increased likelihood of eliciting an MEP at higher conditioning pulses. Conditioning pulses at 95% of the subject’s AMT produced MEPs 85% of the time, whereas at 50% AMT, MEPs were only detected on less than 40% of attempts. This finding suggests that momentary increases of excitability within motor cortex determine the likelihood of activating the corticospinal pathway and helps shed light on the mechanisms by which motor cortex mediates corticospinal output to muscles.