Oregon Undergraduate Research Journal: Vol. 3 No. 1 (2012)
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Cover art: "Untitled number 3" by Christina Lin
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Item Open Access Stomata Density of Orchids and Cloud Forest Humidity(University of Oregon, 2012-11-08) Predovich, SierraThis experiment compares stomata density of the epiphytic Pleurothallis aristata and Maxillaria sp. orchids under experimental conditions of dry and humid environments. Pleurothallis aristata is in the sub-tribe Pleurothallidinae and lacks pseudobulbs, while Maxillaria sp. has pseudobulbs. The study seeks to determine what differences in stomata density exist between the two species, and if there is a difference in mean percent stomata open in humid and dry environments. The study takes stomata impressions from the leaves of twenty individuals of each species using clear nail polish. The results show a significant difference in stomata density between the Pleurothallis aristata and the Maxillaria sp. (Rank Sum Test: t=55, n1=10, n2=10, p<0.05). Additionally, both species have a higher percentage of open stomata in humid environments than in dry environments (Wilcoxon sign rank test). An explanation for these results is that Maxillaria sp. has a pseudobulb for water storage, has a larger leaf surface area, and therefore has higher stomata density. The study showed both species closed their stomata in drier conditions in order to reduce water loss and desiccation. The results of this experiment help demonstrate how different orchid species function in humid and dry environments, and their ability to succeed in the event of global climate change and shifting of biomes.Item Open Access Restoration Monitoring on the McKenzie River, Oregon(University of Oregon, 2012-11-08) Rau, Michelle; Stewart, Jenna; Kezer, Zachariah; Martin, Rebecca; Miller, Ben; Silverstein, Sean; Slivka, Olga; Swanson, Dane; Truelove, Valarie; Van Hevelingen, Thomas; Woods, Tyler; Young, KrystalIn the spring of 2012, we, the Stream Stewardship Team from the University of Oregon's Environmental Leadership Program (ELP), conducted post-monitoring surveys at a side channel of the Middle McKenzie River (side channel 4) to compare with baseline monitoring data collected by the 2011 ELP Restoration Stewardship Team. The goal of this restoration project was to enhance juvenile spring Chinook salmon (Oncorhynchus tshawytscha) rearing habitat within the channel. In 2011 the U. S. Forest Service placed large woody debris (LWD) in five sections of the channel after baseline monitoring to increase the complexity of the streambed within the channel and to create a distribution of sediment optimal for salmon spawning habitat. We conducted pebble counts, cross-channel surveys, and a longitudinal profile of the stream to observe changes since the addition of LWD. Median pebble size decreased downstream of the LWD placements at gravel count 1 and increased upstream at gravel count 2. The percent of embedded sediment decreased at both gravel count sites. We also detected noticeable changes in the stream morphology at four of the five crosssectional surveys as well as along the longitudinal profile. Sediment size distribution and the formation of pools at the downstream end of the channel showed an initial change in stream morphology since 2011, but further monitoring is warranted in order to fully assess the effects of LWD on streambed complexity and salmon spawning habitat.Item Open Access Editor's Letter(University of Oregon, 2012-11-08) Ward, KelseyItem Open Access Editorial: "A Legacy of Undergraduate Research"(University of Oregon, 2012-11-08) Frank, DavidItem Open Access Assessing the Relationship Between Topography and Plant Diversity in Restored and Remnant Wet Prairies(University of Oregon, 2012-11-08) Reed-Dustin, Claire; Logsdon, Willis; Lytton, Rachel; Maloney, Sam; Paulus, Audie; Piazza, Tatiana; Stuparitz, TizianaWet prairies provide numerous ecosystem services and habitat for native plant species. This study examines the relationship between microtopographic variation and plant diversity in six restored and remnant wet prairies in the West Eugene Wetlands to aid future restoration projects. It was predicted that variation in elevation is influential in determining native plant community composition. Along transects within previously established macroplots, soil surface elevation and water depth were measured and percent cover of grasses, forbs, and non-forbs, and measured vegetation and litter height were determined. A linear regression was performed comparing native species richness to the topographic coefficient of variation, which yielded an R2 value of 0.43 and a p-value of 0.16. Although these results are not statistically significant, they demonstrate a meaningful correlation between native plant richness and the coefficient of variation of topography. Further observations additionally suggest that this relationship is present. We suggest further research to determine significant results and suggest the integration of the restoration of microtopography into wetland management.Item Open Access Artist Statement: "Untitled number 3"(University of Oregon, 2012-11-08) Lin, ChristinaItem Open Access The Potential Role of Dietary Intake in Explaining Postoperative Muscle Loss in Total Knee Arthoplasty (TKA)(University of Oregon, 2012-11-08) Robinson, AlexanderPost-operative muscle loss has been identified as the greatest contributor to osteoarthritis patients’ long-term strength deficits, explaining 77% of muscle weakness one to three years after total knee arthroplasty (TKA) for the treatment of osteoarthritis in the knee. Essential amino acid supplementation may help reduce atrophy, but other factors could have an equally influential role. Patients’ food intake could likewise affect atrophy, and thus dietary intake must be measured in order to determine whether essential amino acids reduce muscle loss following TKA. Subjects with a minimal dietary intake could exacerbate muscle loss because fasting causes the body to break down skeletal muscle protein to liberate amino acids for use as gluconeogenic precursors in the liver. As a result, individuals with different diets may experience differing degrees of muscle atrophy. This investigation seeks to test the hypothesis that higher rates of muscle atrophy in subject groups could be explained by comparatively poorer dietary intake. For this study, subjects completed a total of three 24-hour food logs before surgery, then two, and six weeks post-TKA. During these periods, bilateral quadriceps muscle volume was determined using magnetic resonance imaging (MRI). Baseline and six-week whole-body dual-energy X-ray (DEXA) scans were also performed to compare changes in lean tissue and fat mass. Data collected indicated there was no significant difference in dietary intake between the control group and treatment group, suggesting that any muscle saved in the treatment group was a result of essential amino acid supplementation.