21st Denman Undergraduate Research Forum (2016) and Spring Expo

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Development and Assessment of an Oscillatory Motion Tutorial
(2016-03-30) Young, Nicholas; Heckler, Andrew
Our research over the previous two semesters has indicated that introductory physics students are not able to consistently determine the angular frequency, period, or frequency from graphical representations and do not have a firm grasp on these concepts. Since the harmonic oscillator is a fundamental model in many physical and biological systems, it is critical that students understand the concepts and relationships that underlie the model. In order to help students develop these skills, we created a tutorial that could be completed in a 40-minute group work session. The tutorial guided students to work in small groups to complete tasks that involved determining the period, frequency, and angular frequency from graphical representations and mathematical expressions. The tutorial then instructed the students to show that reading these parameters from graphical representations produced the same results as using mathematical expressions to calculate the parameters. Following the completion of the tutorial, a 28-item post-test was administered to the students who had completed the tutorial as well as to a similar group of students who had performed an unrelated task. The students were randomly assigned to the tutorial condition and the control condition before the experiment began. Students in the tutorial condition scored significantly higher than the students in the control group did (t=5.26, p<.001) with a substantial effect size (d=1.04). We hope to use the tutorial as a guide to update our Essential Skills platform, an online application, which is currently being used to assist students in several introductory physics courses in developing the skills to understand oscillatory motion.
Schooling individuals discover a novel food source via social learning faster than non-schooling individuals
(2016-03-30) Troyer, Emily; Hamilton, Ian; Hoskins, Elizabeth
Novel information, such as the location of a new food source, can be transmitted throughout a group via social learning, as opposed to direct sampling of the environment. When learning is asocial, individuals will encounter a novel food source on their own, with no guidance from others. However, in a social learning environment, individuals will learn of a novel food source by directly observing others. Schooling or flocking behavior, which is often seen in fish and birds, also allows for social learning to occur, due to the close proximity individuals have with one another in their group. The purpose of our model was to determine if a schooling behavior could affect the rate at which a population of individuals learned the location of a novel food source. We used an agent based model, in which agents, or individuals, moved around in an artificial environment and interacted with others in their group. We examined three models: a model where learning was asocial and movement was random, a model where learning was social and individuals schooled, and a model where learning was social and movement was random and compared these models against each other. Results show that individuals learn the location of a new food source at a much faster rate when learning is social and the individuals are schooling together. In schooling populations, information about the new food source was shown to be transferred more quickly from individual to individual when compared to a model where movement was random and learning asocial.
An Econometric Study Evaluating the Role of "Office of Patient Experience" on Experiential Outcomes in U.S. Hospitals
(2016-03-30) Jha, Anuvrat; Chandrasekaran, Aravind
Since the inception of the Patient Protection and Affordable Care Act (PPACA), there has been a drastic change in the delivery of healthcare. Payment reform was one of the key attributes of the PPACA, shifting the reimbursement model from fee-for-service to value based purchasing (VBP). In the VBP model, payments are bundled and reimbursement is based on a VBP score. The VBP score is comprised of 70% process management (Quality & Safety) and 30% patient experience during their hospital stay. Patient experience is measured by the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) score. These measures are quantifiable and beginning FY2013, the Centers for Medicare and Medicaid began using the HCAHPS survey to determine reimbursement rates as part of VBP model. Since patient experience has become a vital component of the reimbursement model, hospitals are taking initiatives to improve this patient experience dimension and raise their scores on HCAHPS surveys. One such change is the emergence of “Office of Patient Experience” (OPE) as an independent governing entity responsible for improving patient experience and satisfaction. In this multi-year observational study, we hope to gain insights on the role of such offices across all hospitals in the U.S. and their effects on experiential outcomes in silico. We find that hospitals with OPEs perform better than hospitals without OPEs on six of the ten dimensions of the HCAHPS survey. This study offers theoretical insights on mechanisms to improve patient-centered care through the use of the OPE. Significant practical implication of this research include helping hospital leadership with the decision of whether to invest in an OPE or not and how to structure their OPE.
Grain Size Analysis of Submarine Landslides in the Nankai Trough
(2016-03-30) Rohan, Tyler; Sawyer, Derek
A two part investigation of a mass transport deposit (MTD) in the Nankai Trough, offshore Japan was conducted to learn more about the dynamic behavior of submarine landslides. Hydrometer analysis of 50 sediment samples from the Integrated Ocean Drilling Program (IODP) Expedition 333, Site C0018 was completed with the objective to determine the grain size distribution within a prominent mass transport deposit (MTD-B). Core samples were collected from 90.17 to 191.17 meters below the seafloor (mbsf) with approximately 1 sample per 1 meter collected inside MTD-B. MTD-B was also cored at Site C0021, IODP Expedition 338 providing a valuable opportunity to study a single MTD from two different locations. With the aid of seismic data it was confirmed that both Site C0018 and Site C0021 cored MTD-B. The grain size analysis indicates two major lithologies: clayey silt (78% of samples) and silty clay (15% of samples). The grain size results acquired from Site C0018 were very similar to Site C0021. Both data sets showed a pattern of fining upward inside of the MTD. The grain size analysis of Site C0018 also revealed a defining volcanic ash layer that underlies MTD-B. This observation motivated the second part of this investigation. This second part of this investigation utilized 3D seismic data to examine the discovered volcanic ash layer. This was done with the objective to determine its role in the mobilization of MTD-B. Through examination of the seismic data it can be seen that the ash layer is displaced by MTD-B before reaching Site C0021. With the discovery of the volcanic ash layer underlying MTD-B it became important to determine the volcanic ash’s role in not only in the mobilization of MTD-B, but also in the mobilization of other landslides throughout the Nankai Trough region. With 3D seismic data the volcanic ash horizon was able to be mapped throughout the Nankai Trough seismic survey area. With the horizon mapped it was possible to locate another landslide that is positioned on-top of the same volcanic ash layer, exemplifying how the discovered ash layer may have been a weak layer allowing submarine landslides to mobilize throughout the region.
Gender Differences in Venture Capital Funding on ABC’s Shark Tank
(2016-03-30) Hunt, Tyler; Greco, Ralph; West, Patricia
ABC Network’s reality television show “Shark Tank” gives entrepreneurs the opportunity to pitch their ideas to a panel of investors for the chance to receive funding. Each season more than 35,000 entrepreneurs apply to be on the show. Whether they receive an offer for funding or not, they still stand to gain the free advertising that comes with appearing on a show with more than seven million average viewers per episode. Although there are abundant resources for knowledge on Shark Tank, women in venture capital, and behavioral gender differences, sources are lacking on gender differences in venture capital funding on Shark Tank. The purpose of this research is to determine if differences exist in how entrepreneurs receive funding based on their gender. To analyze this, I utilized two publicly available datasets containing information on the pitches aired on the show. These datasets were cleansed and merged to form one data set with thirty-five variables spanning across four seasons and 235 pitches. I found that despite having comparable or better businesses than their male counterparts, women ask for lower valuations and accept deals at a lesser percentage of what they asked for compared to men. Explanations for these differences were considered in regards to the industry, sharks, entrepreneurs, and society. This information can be applied to benefit entrepreneurs in search of venture capital, and specifically, future contestants on the show. Going forward this research can be improved by coding for more variables and including data from the rest of the seasons.
Effect of diet and bacterial clearance on energy expenditure in the cockroach Periplaneta americana
(2016-03-30) Ondrejech, Andy; Munoz-Garcia, Agus; Ayayee, Paul
Gut microbiota presumably constitutes an important source of essential nutrients in insects. To study the effect of microbiota on the nutritional state of animals, it is common to use antibiotics and observe the effects of bacterial clearance. However, there might be a confounding effect between the physiological effects of nutritional stress and those produced by the antibiotic itself. In this study, we investigated the effect of clearance of gut microbes in the American Cockroach (P. americana). We fed cockroaches with either a high quality diet (dog food) or a low quality diet (dog food, 30%, mixed with cellulose, 70%). Within each group, we administered the antibiotic Chloramphenicol in a low dose (~500 ppm) or a high dose (~ 5000 ppm), and we kept animals free of antibiotic. We measured energy expenditure of cockroaches using the manual bolus integration technique, on the day they were assigned to each group and seven days after treatment. On day seven, we extracted DNA from cockroach guts and we run quantitative PCR to determine bacterial load. With this design, we propose that we are going to be able to tease apart the effects of diet and antibiotic dose on the nutritional state of animals.
Facebook Happiness
(2016-03-30) Lu, Kailun; Smith, Robert; Reczek, Rebecca; West, Patricia
As the world’s largest social networking site, Facebook has reached 1.59 billion monthly active users around the globe as of December 2015. People access Facebook because they want to connect with their friends and family. People want to find happiness on Facebook, but do they? The purpose of this research is to measure how Facebook users’ emotions change after looking at Facebook, and the role played by different types of Facebook posts and its social comparison. The research was conducted online using 128 college students ranging from the ages of 16 to 41. Since Facebook users were exposed to many events throughout the day, researchers believed that there were mainly four types of events that people share on Facebook: Lifetime Events, Special Events, Routine Events and Neutral Events. Participants were randomly assigned to view a Facebook “news feed” full of one of the Lifetime Events, Special Events and Routine Events combined with some Neutral Events. Then they were asked to think about an acquaintance who posted these events on Facebook. Participants reported their positive and negative affect both before and after looking at the Facebook posts, and difference scores were calculated by subtracting the pre-Facebook affect scores from the post-Facebook affect scores. The results of a one sample t-test were shown to be significant and revealed that participants felt a less positive affect after looking at Facebook than they did before looking at Facebook. The results suggest that viewing Facebook decreases a user’s positive emotional state. A correlation test was used to see if comparing with users’ Facebook friends made them feel bad or not, and the results show that Facebook users do not realize that going on Facebook makes them feel worse. Additional research is planned to further examine how different types of Facebook posts may differentially affect positive affect. In conclusion, Facebook viewing has a negative effect on users’ emotional state. Facebook users seem unaware that this is happening, and additional research is planned to shed further light on this effect.
Scaling Social Enterprse in Developed and Developing Countries
(2016-03-30) Rumburg, Kelsey; Tansky, Judith
Social enterprise is an emerging field focusing on the use of entrepreneurship and earned income to run a business with a social focus and mission. While the idea is certainly not new, academic analysis, coursework, and degree programs are a recent development in this interdisciplinary subject. Prominent research in the field currently focuses on the key traits of a social entrepreneur, case studies for specific countries, and the sectors in which social enterprise develops and thrives. However, very little research has been done on social enterprise as it spans different economies. As social enterprises seek to solve major societal issues, such as poverty, poor education, and lack of empowerment, understanding the most effective growth strategy for social enterprise is key in maximizing impact of the organization. This research will focus on the scalability of social enterprise models that transcend both borders and stages in economic development. Through qualitative case study analysis and review of the current commercial and social enterprise scaling literature and methodology, a framework has been developed for designing social enterprises that seek to scale in a way that they can operate in both developed and developing countries. Key findings show that differences do exist in social enterprise development in different economic situations, and that scalability is a matter of leveraging core competencies that provide economic and social value and understanding and adapting the business model as fit. This framework, designed for social enterprise practitioners, has been validated with case study comparison of social enterprises that operate in both economies. This is significant because the social enterprise sector is expected to grow rapidly over the next decades, thus understanding and implementing scale effectively is imperative for continued success of many social enterprises.
Registered Nurses’ Perception of Top of License Practice Activities
(2016-03-30) Hlahol, Melanie; Chipps, Esther
The rapid changes in health care in tandem with the increasing complexity of inpatient care requires that nursing leaders and healthcare administrators think carefully about how best to maximize the education and skill set of the Registered Nurse (RN). Given the shortage of healthcare providers, gaps in care often fall to the RN, and thus RNs have to take on responsibilities that fall below their scope of practice. RNs therefore are unable to perform other activities that they see as value added, such as spending more time with the patient and providing important patient education. The purpose of this study is to explore nurses perceptions of what practices constitutes top of license practice. This is a qualitative study using focus groups in which we asked both bachelor and associate degree prepared nurses a list of questions that categorized their daily activities and explored their perception of what activities were top of license. A constant comparative method was used to identify and examine nurses’ activities. Preliminary results suggest that nurses may not be practicing to their full educational capacity. These findings will provide the forum to begin to discuss new and innovative ways to maximize nursing work models.
Argentine Tango Practice as a Balance Intervention for Cancer Survivors
(2016-03-30) Lamantia, Marie; Worthen-Chaudhari, Lise; Covey, David
Cancer survivors have reported that problems in balance and walking are a leading cause of distress and discomfort post-cancer. This critical loss of balance function is attributed to deconditioning and peripheral neuropathy resulting from chemotherapy treatments or lymphedema. Our study evaluates feasibility of the use of Argentine Tango to improve balance among cancer survivors, focusing on survivors who are deconditioned or nerve damaged (e.g. Chemotherapy Induced Peripheral Neuropathy). Our primary aim is to determine the feasibility of conducting a 10-week, dance-based balance intervention given concerns regarding retention and compliance among participants who are receiving concurrent care in oncology and rehabilitation. Our follow-on aim is to establish pilot data regarding the impact of participation on balance function, specifically on balance measures that have been shown to correlate to participant risk of falling (i.e., root mean square medial-lateral sway amplitude during eyes closed condition). We offered 20 sessions (1-hour each) of Argentine Tango over 10 weeks and collected the following data each class: attendance, satisfaction with intervention. In addition, at three time points (baseline, 5 weeks, 10 weeks) we collected a biomechanical measure of fall risk. Satisfaction with intervention was high for cancers survivors and controls. In addition we report balance data from a group of cancer survivors with peripheral neuropathy post cancer due to chemotherapy or lymphedema and age-matched controls. At the beginning of the intervention this group of cancer survivors started at higher than normal medial-lateral sway indicating high fall risk, but ended within normal range by midpoint (5-weeks) of the intervention. The cancer survivors showed an average 56% reduction in medial-lateral sway at midpoint (p<0.01) achieving values comparable to controls. This work provides the first known evidence regarding whether cancer survivors find a dance-based intervention, Argentine Tango, satisfying and feasible for balance improvement. Improved control of lateral stability after 5-weeks of practice indicates that Argentine Tango is a promising balance intervention for cancer survivors experiencing impaired balance post treatment.
The Impact of Sudden Changes in Title I Funding on Ohio School Districts
(2016-03-30) Conrad, Cameron; Weinberg, Bruce; Lavertu, Stéphane
Through the 1965 Elementary and Secondary Education Act (ESEA), the federal government established Title I funding to target resources for districts serving low-income students. The reauthorization of ESEA in 2001 expanded the program’s funding significantly, making Title I the largest federal education finance program aimed at improving the achievement of low-income students, yet the impact of this funding on disadvantaged students is still heavily debated. Determining the causal impact of Title I funding on district spending and student learning is difficult because the poverty counts at the center of the funding formula are also correlated with these outcomes. This study exploits the fact that changes in federal student poverty counts due to the 2010 Census, which are unrelated to actual changes in district poverty levels during that same time period, led to significant changes in Title I allocations across districts. I exploit these changes in funding to implement an instrumental variables research design to determine the causal effect of sudden changes in Title I funding on Ohio school districts. This paper finds that sudden changes in Title I allocations increase total, state, and federal revenue initially, but in the long-run a local offsetting response subsequently results in a negative effect for instructional expenditures. The results suggest that Title I has little to no effect on student achievement.
Trends in Reasons for Restatements
(2016-03-30) Brackman, Kyle; Dietrich, Richard
In 2014, more than 500 companies or over 3% of all public companies filed a Form 8-K Item 4.02 disclosure indicating that a previously issued financial statement should not be relied upon due to a material error. These material errors mislead investors, creditors, and other stakeholders. Therefore, such a company is subsequently required to issue corrected financial statements through a Form 10-K/A disclosure. By understanding the underlying errors that drive companies to restate, accountants can take actions to minimize the quantity of restatements. Previous research has examined the relationship between the passage of time and the number of restatements. This study adds to the discussion by describing reasons that companies restate and the associated trends. Audit Analytics database provided by Wharton Research Data Services was used to analyze all Item 4.02 disclosures from 2004 to 2014. These restatements were classified by whether clerical error, fraud, accounting error, or another type of error led the company to restate their financials. The results indicate that the proportion of restatements explained by clerical errors has fallen from over 14% in 2008 to about 1% in 2014. The proportion of restatements explained by fraud has fallen from over 3% in 2004 to under 1% in 2014. As a result, the proportion of restatements explained by accounting errors has increased from about 86% in 2008 to over 98% in 2014. These results are consistent with the presumption that increased regulation, technology, and education may reduce fraud and clerical error over time. The total number of restatements has more than doubled since 2008 despite evident decreases in the proportion of restatements explained by clerical error and fraud. As the proportion of restatements explained by accounting errors predominates, actions must be taken to reduce accounting error and consequently diminish the total number of restatements.
A systematic review of the link between childhood obesity and adult cancers
(2016-03-30) Schumacher, Makaila A.; Smith, Laureen H.
Over the past three decades, Americans’ rates of overweight and obese have steadily increased. It has been suggested that childhood obesity may increase the risk of cancer in adulthood. Much literature has focused on specific cancers or the mechanisms of obesity and its sequelae. Consequently, a systematic review is needed to more fully examine the relationship between childhood obesity and adult-related cancers. This review examined the evidence of the obesity and cancer relationship. A secondary aim was to determine the adult cancers most associated with childhood obesity. Pubmed and Cinahl were searched during the fall of 2014. Criteria for inclusion were peer-reviewed articles published within the last ten years and included variables of interest of childhood obesity and adult-related cancer. Possible bias may be present because of intra-rater reliability. Other forms of bias could be from no unpublished articles or books being included and the review being science-oriented. Thirty out of a possible 658 articles were chosen for final review based on established parameters and applicability of information. Strong evidence was found supporting a link between childhood and adolescent obesity and specific types of adult cancers. A positive association was found with non-Hodgkin lymphoma and thyroid cancer in males and females; esophageal squamous cell carcinoma and colorectal adenoma in women; and renal cell carcinoma and colon cancer in males. A negative association was found with premenopausal breast cancer in women. Limited evidence of a positive association was found with colorectal and kidney cancers in males and females, and conflicting evidence was found for postmenopausal breast cancer in women. This review supports a link between childhood obesity and adult-related cancers and shows how these relationships may differ by gender. This review demonstrates the importance of efforts for early childhood obesity prevention to mitigate negative health outcomes later in life.
Characterization of Loading Environment on Human Ribs during Respiration
(2016-03-30) Stemmer, Katherine; Bolte, John H., IV
The human thoracic cavity holds vital organs, such as the heart and lungs. The rib cage provides protection to these organs, and as a result is susceptible to injuries. One important determinant in the susceptibility of ribs, and bone in general, to fracture is the accumulation of microfractures. These microfractures occur in ribs due to cyclic loading and stress during normal ventilation. Since microfractures accumulate in regions of bone that experience high local strains, it is important to measure the strain patterns ribs experience during the regular loading environment of breathing. The strain mode of the cutaneous cortex and pleural cortex of the rib is unknown and failing to account for how the rib responds to the loading (i.e., initiates microfractures) will affect the accuracy of a physiological model. The objective of this study was to determine the strain modes and magnitudes experienced by the ribs during ventilation. One Post-Mortem Human Surrogate (PMHS) was instrumented with strain gages on the pleural and cutaneous surfaces of ribs 3-9, along with two strain gages on the sternum, resulting in a total of 86 gages. A bladder and air pump were used to mimic ventilation in a defined combination of shallow and deep breaths. Results include location comparisons in strain between bilateral rib pairs, quantification of variation in strain mode (tension versus compression) based on location, and differences in strain magnitudes along the length of the rib. These results will improve researchers’ understanding of physiological strain in the ribs during ventilation and potential for microfracture initiation and repair. A greater comprehension of fracture susceptibility will help researchers improve biofidelic models and their understanding of the loading environment to which the rib is adapted.
Ed Watson: Teaching Big Data to K-12 Students
(2016-03-30) Muhammad, Stephanie; Kelley, Jaimie; Stewart, Christopher; Stewart, Christopher
Online data-intensive (OLDI) services such as Google Now, Apple Siri, and IBM Watson provide answers to questions formed using natural language. Although these services are widely used, K-12 students are rarely introduced to concepts relating to them. A lack of early exposure to these concepts force the chances of students developing academic or career interests relating to OLDI concepts to rely on the exposure they may receive during their pursuit of higher education. The Ed Watson educational package is a proposed solution to counteract the lack of exposure at the K-12 level. Ed Watson introduces K-12 students to natural language processing (NLP) and inverted indexing using a 30 minute lecture presentation and an interactive Jeopardy! game. The interactive Jeopardy! game demo allowed students to compete against a computer player that used many of the same concepts they learned about during the lecture to answer Jeopardy! questions. The package was demoed to a group of middle school students. The group was surveyed before and after the package presentation to determine changes in the student’s attitudes about “big data” and their ability to answer technical questions about OLDI concepts. Early results showed a 54% increase in student interest in big data. Ed Watson also increased the number of students that correctly answered questions about OLDI concepts by an average of 60.5%. The result of this early demonstration showed the Ed Watson package’s potential in providing K-12 students with an early exposure to OLDI concepts. Additional demonstrations of the package will be used to develop a complete package that can be downloaded and used by instructors for their own students.
Vulnerability of the National Electric Grid to Renewable Power Consumption
(2016-03-30) Elsbernd, Kenneth; Drobny, Neil; Greco, Ralph; West, Patricia
Trends over the past 25 years suggest a decline in fossil fuel consumption per capita and an increase in per capita consumption of renewable energies. Consumption per capita of energy generated from fossil fuels, as a percentage of the total per capita consumption, declined from 92.3% to 89.3%, while per capita consumption of renewables increased from 7.7% to 12.0%. Should these trends persist, the utilities sector could be in danger of decreased profits, which could lead to cost cutting measures and ultimately a lessening of maintenance for the national electric grid in the distant future. A multiple linear regression model was created to forecast the future affect that a switch in energy consumption would have on the utilities sector in the United States and the price sensitivity in different sectors. The model utilizes annual renewable energy consumption per capita and sector-based electricity pricing to predict the annual consumption of fossil fuels per capita. Forecasts for fossil fuel consumption per capita could show how the current landscape of the utilities sector, which generates power largely from fossil fuels, will be troubled, should sector strategies not adapt. Based off of the predictive model, should current trends persist, the utilities sector will see decreasing profits. To counteract lower profits, electricity prices may increase to some customers, potentially causing consumers to search for alternate sources of electricity. Though not an immediate threat due to its small share of the energy market, renewable energy trends suggest that consumer’s source of energy will shift in the future, from fossil fuels to renewables. Additionally, changes in regulation throughout the industry could alter the energy landscape further. Without a change to the current structure of the utilities sector, and if facilitated by regulatory alterations, customers could increasingly leave the national electric grid in favor of lower cost alternatives.
Role of aminoacyl-tRNA synthetases and viral RNA structure in the initiation of reverse transcription
(2016-03-30) Hatterschide, Joshua; Cantara, William; Wu, Weixin; Musier-Forsyth, Karin; Musier-Forsyth, Karin
Human T-cell leukemia virus type-1 (HTLV-1) is a human retrovirus that causes adult T-cell leukemia/lymphoma (ATL)—a rapidly degenerative non-Hodgkin’s lymphoma that affects roughly 5% of infected individuals. According to the most recent estimates, 5-10 million people are infected with HTLV-1 worldwide, yet there are currently no successful therapies for ATL. This underlines the importance of further research into the retroviral lifecycle. Before the genome of a retrovirus can be integrated into the host cell genome, it must undergo reverse transcription (RT) from RNA to DNA. In order for RT to initiate, a tRNA primer must anneal to the primer binding site (PBS) in the 5’ untranslated region (5’UTR) of the retroviral genome. Our lab has demonstrated that human lysyl-tRNA synthetase (hLysRS) facilitates this process in HIV-1 by binding a tRNA-like-element (TLE) near the PBS, localizing the tRNALys3 primer. The primer for HTLV-1 RT is tRNAPro; therefore, we hypothesize that this virus could employ a similar mechanism involving human prolyl-tRNA synthetase (hProRS) binding to a TLE. The secondary structure of the HTLV-1 5’UTR was solved using Selective 2’ Hydroxyl Acylation analyzed by Primer Extension (SHAPE), revealing a possible TLE stem loop that resembles the anticodon of tRNAPro and displays high sequence conservation across known isolates. Equilibrium binding studies and RNA probing techniques are being used to characterize the interaction between hProRS and the HTLV-1 5’UTR. Fluorescence anisotropy competition assays have shown that the HTLV-1 5’UTR is capable of competing tRNAPro off of hProRS. Preliminary RNase and SHAPE probing experiments have been performed, and experiments to probe the HTLV-1-hProRS and the HIV-1-hLysRS complexes are in progress. These experiments will allow us to characterize and compare the involvement of aminoacyl-tRNA synthetases in the initiation of RT, and provide insight into an important retroviral mechanism and potential drug target.
Isolation and Genomic Analysis of Bacteria that drive biogeochemical cycling in Prairie Pothole Lake sediments
(2016-03-30) Lynes, Mackenzie; Johnston, Michael; Dalcin-Martins, Paula; Wilkins, Michael
The prairie pothole region of North America, covering approximately 750,000 km2, contains millions of small lakes that are important systems for regional carbon and sulfur cycling. Prairie pothole lake (PPL) sediment pore waters contain some of the highest dissolved organic carbon concentrations ever measured in freshwater ecosystems. Sediment and pore water samples from the PPLs of North Dakota were used to anaerobically enrich for sulfate reducing bacteria (SRB) and fermentative microorganisms. Given the high sulfate concentrations characteristic of PPL pore waters, we suspect that SRB play an important role in coupled carbon and sulfur cycling, while fermenters degrade more complex carbon substrates into labile compounds. A range of medias, enrichments, and methods were used to cultivate and isolate representative microorganisms, with growth monitored through assays and epifluorescence microscopy. As a result, isolates 1L (a SRB growing with sulfate and lactate) and YPD1 (a fermenter) were obtained. A BLAST search of the 16S rRNA sequence from 1L revealed that it was closely related to Desulfovibrio magneticus. While Desulfovibrio sp. 1L tolerated elevated sulfide concentrations (up to 6mM), salinity of growth media was a strong constraint on growth. The genome of YPD1 showed the isolate to be Proteinoclasticum ruminis. Future studies will continue to analyze the genomes of these isolates and determine their role in PPL sediments through planned experimentation. Studying the interactions of these isolates with other key microbes in the community such as methanogenic archaea will provide insight into key processes driving carbon and sulfur cycling in the environment.
Nonanoic Acid Exhibits Inconsistency Between Bulk and Surface pKa
(2016-03-30) Lach, Evan A.; Wellen, Bethany A.; Allen, Heather C.
Organic molecules at the ocean surface influence the climate through their reactions as coatings on sea spray aerosols, although many complex processes have not yet been fully described. By further characterizing molecules at this surface, climate effects through aerosol processes could be deduced. One common organic at the ocean surface is nonanoic acid (NA), which may be formed via the oxidation of oleic acid by gas phase species such as ozone. The pKa for an acid is characteristic and gives insight into its reactivity, but its value at the air-water interface is not necessarily the same as in bulk solution (~4.8 for many organic acids). The reactivity of sea-surface carboxylic acids cannot be well predicted without an accurate value of surface pKa. By varying pH via titration and simultaneously measuring the surface tension of a NA solution via a Wilhelmy platinum plate, the surface pKa of NA can be obtained. The surface pKa of NA would be shown on the titration curve of surface tension versus pH as the inflection point. At pH 12, NA is ionized and its surface tension is 70.68 mN/m, near that of neat water (72.80 mN/m). At pH 3, the surface tension of NA is 30.49 mN/m, showing an increase in surface activity. Additionally, Brewster angle microscopy (BAM) will be used in the future to image NA at the surface at different pH values. With an accurate pKa and visual evidence of the surface activity of nonanoic acid, the atmospheric impact of aerosols could be further described. Investigation of this inconsistency is a first step to better predict climate change.
Interaction of Retronasal and Orthonasal Perception of Unfamiliar Flavors
(2016-03-30) Moeller, Lindsay; Simons, Christopher
Aroma compounds can be perceived through orthonasal (through the nose—smelling) or retronasal (through the mouth—flavor) mechanisms. These signals are processed by the same receptors and by the same sections of the brain, but are thought to elicit different perceptions, hedonic responses and behaviors. In this experiment, sensory evaluation of unfamiliar flavors by retronasal (flavor) and orthonasal (smell) perception were studied. The unfamiliar flavors used were Yuzu, Carambola, Hibiscus, and Momo. A matching test wherein panelists were given a reference sample containing one of the aroma compounds and told to identify that sample amongst the four unknowns was performed for three different evaluation scenarios: orthonasal to orthonasal perception, retronasal to retronasal perception, and retronasal to orthonasal perception. For each condition, the probability of a panelist correctly guessing all of the matching samples is 0.39%. McNemar's Test for Correlated Proportions was used to identify significant differences in correct responses for the three conditions. When data from all flavors were combined, retronasal to orthonasal matching proved to be most difficult. Indeed, significantly more samples were correctly matched when reference and target samples were both evaluated retronasally (retronasal-retronasal; p=0.039). This difference approached significance (p=0.062) when the reference and target samples were both presented orthonasally. For the Carambola and Momo flavors, significantly fewer retronasal-orthonasal matches were made compared to the orthonasal-orthonasal evaluations (p=0.020 and p=0.038, respectively) and retronasal-retronasal evaluations (p=.003 and 0.008; respectively). Hibiscus and Yuzu only showed significant differences when comparing the orthonasal-orthonasal condition to the retronasal-orthonasal condition (p=0.038, p=0.043). Overall, these results can be used in the flavor and food industry in order to better understand how the application of aromatic flavors leads to different perceptions by consumers when evaluated by nose or by mouth.

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