Tag: Poster 1

Fall Risk in the Elderly and Joint Moments of the Supporting Lower Limb during Sit-to-Walk

Presenter: Elena Absalon

Mentor: Li-Shan Chou

AM Poster Presentation

Poster 1

Elderly adults suffer a high incidence of falls during daily activity. It is well documented that dynamic balance and muscle strength deteriorate with age. The goal of this study is to compare total support moment and joint moment distribution of the supporting lower limb during the sit-to-walk transition in groups of young, elderly faller and elderly non-faller subjects (≥ 70 years). Force plate and three-dimensional motion analysis data were collected during several trials of the Timed Up and Go test (TUG) to calculate total support moment and joint moments at the hip, knee, and ankle during sit-to-walk. Significant differences between the groups were found in the amount of ankle joint moment produced at seat-off and swing-off events. There were not significant differences in total support moment, hip, or knee moments at these events. However, there seems to be variation in the patterns of the total support moment graphs between the groups. The variation in the ankle moment between the groups identifies the correlation between the torque produced around the ankle and balance performance. The differences in total support moment patterns found between faller, non-faller, and young groups indicate different strategies used to perform the sit-to-walk motion that may compensate for impaired balance. The relevance of this study is that it provides a correlation found between balance performance and joint moment contribution, which would be useful in creating a fall prevention and balance treatment plan.

The Indigenous Siberian Health and Adaptation Project: Seasonal Variation in Autoimmune Thyroid Disorders among the Yakut (Sakha) of Siberia

Presenter : Vimal Balu

Mentor : Josh Snodgrass

Major : Biology, Anthropology

Northern populations physiologically adapt to extreme cold by upregularing basal metabolic rate. The thyroid appears central to this adaptation. Thyroid hormones regulate metabolic responses to chronic cold among indigenous Arctic populations. However, it is un- clear whether this adaptation among circumpolar groups predisposes them to autoimmune thyroid disorders (AITDs). This study ad- dresses this question by examining correlates of seasonal variation in anti-thyroid peroxidase antibody (TPOAb) concentrations among the Yakut of Siberia. Anthropometric and biomarker data were obtained on two occasions (Summer 2009 and Winter 2011) on a sample of Yakut men (n=52) and women (n=88) (≥18 years old). TPOAb levels are higher in summer than winter in both men (P<0.01) and women (P<0.05). Women have significantly higher TPOAb levels than men (P=0.05), and are more likely to have an AITD (28% of women versus 4% of men; TPOAb >30 IU/mL). TPOAb concentrations are associated with several anthropometric dimensions among men (negative trends with weight [P=0.08]). Finally, changes in TPOAb showed a positive trend association with change in thyroid stimulating hormone (TSH; P=0.06) among men, but among women change in TPOAb was negatively associated with change in HDL cholesterol and showed a positive trend with change in triglycerides (P=0.1) and hemoglobin (P=0.08). This study documented impor- tant sex differences in AITD risk among the Yakut, and an unexpected drop in TPOAb levels between summer and winter.

Sutural Methodology for Determining Age in Rhesus Monkeys (Macaca mulatta)

Presenter: Julia Arenson

Mentor: Frances White

Poster: 1

Major: Anthropology 

Cranial sutures are frequently used to determine age in forensic and bioarchaeological contexts. However, these methods are mostly only utilized in human populations, and a lack of comparative data for non-human primates makes visualizing the evolution of growth patterns difficult. This project documents cranial suture fusion in rhesus monkeys (Macaca mulatta) as a marker of development. To develop a standardized methodology, I used Meindl and Lovejoy’s (1985) established 0-3 point scale for human ectocranial fusion, and scored sutures all over the cranium that were included in Wang et al.’s research (2006). My sample included osteological specimens with known ages from the UO Comparative Primate Osteological Collection, ranging from 0 to over 14 years, totaling15 specimens (5 females and 10 males). Total percentage fusion of each region of the skull, divided into facial, neurocranial, and basicranial regions, revealed which areas correlated positively with age, while analysis of scoring precision over 10 trials of the same specimens showed which sutures were not scored reliably. Sutures on the neurocranium and face gave the best age correlates, while sutures within the eye orbit and the squamosal suture were not consistently scored. To best estimate the age of an osteological specimen, the findings suggest a focus on sutures of the face and neurocranium. Developing comparative methods to evaluate growth patterns can allow researchers to identify the changes and consistencies of important life history events within both human and nonhuman primate evolution.

Bergmann’s Rule in Skull Size and Clinical Variation in Skull Shape of Wild Versus Captive fascicularis Group Macaques

Presenter: Julia Arenson

Mentors: Frances White and Stephen Frost, Anthropology

Poster: 1

Major: Anthropology

Bergmann’s rule predicts that body size increases with distance from the equator. This pattern has been noted in wild macaque populations, but relocated captive populations have not been examined for this cline. Captive populations provide an opportunity to analyze whether Bergmann’s rule is influenced more by natural selection or phenotypic plasticity. Forty-five 3D cranial landmarks were collected using a Microscribe-3DX on a sample of 251 adult crania of wild Macaca fascicularis, M. cyclopis, M. fuscata and M. mulatta with known provenience, as well as 18 captive M. mulatta from Beaverton, OR (lat=45.5) and 40 from Cayo Santiago, Puerto Rico (lat=18.2). Cranial centroid size was calculated for each specimen as a proxy measure of body size. The covariation between shape and geography was assessed with a 2-Block Partial Least Squares (2B-PLS) analysis. Regression analyses were used to predict the expected latitudes for the captive samples based on size and shape. For wild macaques, distance from the equator was significantly correlated with both size (males R2=0.370; p=0.00; females R2=0.475; p=0.00) and shape (pooled sex R2=0.51, p=0.00). Predicted latitudes based on cranial sizes (Beaverton=38.0; Cayo Santiago=44.9) were higher than the current captive locations but were lower when based on shape (Cayo Santiago=13.3; Beaverton=8.5). These results suggest the latitudinal pattern of skull shape and size in wild fascicularis group macaques is more influenced by phenotypic plasticity than natural selection.

“Air Proof My Leaking Apartment”: Design Heat Lost through Infiltration in Old Apartment Buildings

Presenter: Sharon Alitema

Co-Presenters: Maryam Alnemer, Yue Gu

Faculty Mentor: Alison Kwok, Jenni Hyunh

Presentation Type: Poster 1

Major: Architecture

Infiltration, a common source of heat loss, especially in old houses, is the unintentional introduction of outside air into a building. Air escapes through cracks of the building’s envelope, windows, and through use of doors. This
case study focuses on an old duplex apartment in Eugene where infiltration is most pronounced in the winter due to indoor-outdoor temperature differences. The hypothesis was that by sealing the large leaks/cracks in the apartment, it would result in a 50% reduction in infiltration, allowing the apartment to maintain a room temperature of 68 °F. A powerful fan, blower door, that enables one to identify major air leaks by lowering the air pressure inside the house and letting air flow through all unsealed cracks, was used to test these hypotheses. Temperature values were recorded before and after possible solutions were implemented. While the hypothesis predicted a 50% reduction in infiltration, the 41.1% reduction achieved proved infiltration was the greatest contributor of heat loss. Further analysis revealed that the reduction of infiltration, led to energy saving costs of about up to $50 during the winter months.

Tectonic Tremor And Seismic-Wave Attenuation in Cascadia

Presenter(s): Geena Littel − Geophysics

Faculty Mentor(s): Amanda Thomas

Poster 1

Research Area: Natural/Physical Science

Funding: UO Department of Earth Sciences: Walter Youngquist Fellowship, James C. Stovall Fellowship, UROP VPRI Fellowship, UROP Mini Grant

In addition to fast, seismic slip during an earthquake, many subduction zones also host slow, largely aseismic slip. These “slow earthquakes” occur on timescales of weeks to months and are often accompanied by a weak seismic signal known as “tectonic tremor,” or simply “tremor.” Tremor behaves differently than regular earthquakes in that it is comprised of many small earthquakes that radiate low-frequency seismic energy and originate at the plate interface downdip of where large earthquakes typically occur. Ground-motion prediction equations (GMPEs) quantify ground-motion during an earthquake, and employ estimates of seismic-wave attenuation, that is, the decrease in amplitude of seismic waves as a function of distance from the earthquake source. Because tremor occurs frequently when compared to regular earthquakes in Cascadia, it presents an opportunity to better refine attenuation parameters for use in GMPEs. Here we quantify seismic-wave attenuation by performing an inversion using tremor ground motion amplitudes from three tectonic tremor episodes to determine the extent of regional variations and frequency dependence of seismic-wave attenuation in Cascadia. Inversion refers to the process of using tremor ground motion amplitudes, and a mathematical formulation relating seismic-wave amplitude and other known parameters, to solve for the unknown parameter- in this case, attenuation. Due to the large amount of tremor data, we can resolve spatial variations in the attenuation parameter along strike in Cascadia. As well, tectonic tremor exhibits the frequency dependence expected for attenuation, as seen in GMPEs developed from moderate to large magnitude earthquakes. Hence, tectonic tremor can be used to provide insight into the geological and physical factors manifested in attenuation and refine estimates of attenuation for ground-motion prediction, thus having important implications for hazard assessment.

Nitrogen Composition in Native and Invasive Plants in Relation to Ant Mounds in Serpentine Grasslands

Presenter(s): Elizabeth Baach

Faculty Mentor(s): Lauren Hallett & Eliza Hernández

Poster 1

Session: Sciences

The project I will continue to work on addresses the question, ‘is there a significant difference in nitrogen composition of plants on and off ant mounds in a low nutrition environment, serpentine grasslands?’. This research is significant in two ways: First, it furthers previous works that investigate the relationship between subsurface dwelling animals and the nutrient availability for the plants that grow on the mounds they create. While there has been significant research looking at these relationships, there is less on analyzing elemental plant composition as I propose here. Second, my research will be contributing to the academic understanding of ecology by looking at serpentine grasslands in a new way. These serpentine grasslands receive a lot of attention from academic researchers as the soil in the area has low quantities of essential nutrients, phosphorus and nitrogen, and high levels of toxic heavy metals; this specific soil composition only allows specialized plant species to survive. These plants dominated these grasslands, however, recent research has shown that human activity has increased nitrogen deposition, allowing invasives to begin establishing and outcompeting the native flora. The way I will be furthering this well established understanding of these grasslands will be through the examination of nitrogen content of both native and nonnative grasses and forbs that could be gaining nitrogen naturally or through nutrient upwelling caused by ants. Looking at previous research, my experimental design and considering nitrogen deposition, I expect to find that there will be higher nitrogen composition in invasive plants when comparing native to nonnative status plants. I also believe that plants situated on ant mounds will have higher nitrogen composition than those away from the mounds, this because non-native plants have been shown to outcompete native species in high nitrogen conditions and because ants bring up previously unavailable nutrients to plants.