20th Denman Undergraduate Research Forum (2015)

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    Construction of a Thermococcus kodakarensis Deletion-Strain Library
    (2015-03-25) Lin, Jean; Staikoff, Jenna; Angelotti, Austin; Reeve, John; Matsumi, Rie
    The biological world is divided into three primary Domains, two prokaryotic Domains, the Archaea and Bacteria, and the Eukaryotes. The Archaea were only first recognized late in the 20th century and, at first, proved difficult to investigate due to the lack of genetic systems. This barrier was removed by the discovery in 2003 that Thermococcus kodakarensis, a hyperthermophilic Archaeon, is naturally competent for DNA uptake and genetic recombination. Since then, to take advantage of this discovery, many genetic tools have been developed and we are now constructing a T. kodakarensis deletion–strain library. The genome is predicted to contain 2,306 protein-encoding genes, and are constructing individual strains, each with one non-essential protein-encoding gene deleted. To do so, each gene is first cloned to generate a plasmid (designated an A-plasmid) that is transformed and amplified in E. coli. Oligonucleotide primers are then used to prime inverse polymerase-chain reactions (PCR) using the A-plasmid DNA as the substrate that generates a B-plasmid, a plasmids in which the target gene is precisely deleted. The accuracy of each deletion of a target gene is confirmed by DNA sequencing. The B-plasmid is then used as donor DNA to transform T. kodakarensis and so introduce the deletion into the T. kodakarensis genome. To date, we have constructed and confirmed by DNA sequencing, >2000 A-plasmids, ~700 B-plasmids and ~100 T. kodakarensis deletion strains. When finished, this will be the first archaeal deletion-strain library and will serve the archaeal research community as a resource for investigations of all aspects of archaeal biology, physiology, and hyperthermophily. It will also provide a valuable tool for investigations of the many molecular biology features that are common to Archaea and Eukaryotes.
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    Stability of Total Phenolics and Anthocyanins of Three Types of Black Raspberry Confections During Storage
    (2015-03-25) Guo, Aina; Vodovotz, Yael
    Berries are recognized for their health-promoting properties and roles in disease prevention. The major components in black raspberries that have been linked to chronic disease prevention are phenolic compounds, such as anthocyanins, proanthocyanidins and ellagitannins. Of these, anthocyanins are present in the highest quantity and have been studied for their role in prevention of heart disease, cancer and obesity. These phenolic compounds, however, are unstable during storage and can be easily degraded by factors such as temperature, sunlight, oxygen, and enzymes. Moreover, during long-term storage, the anthocyanins can undergo polymerization and form pigments, influencing the color of the products and their bioactivity. The objective of this study was to determine the effect of storage temperature (4℃ and room temperature) and storage time (2 months) on the total phenolics and anthocyanins content as well as polymeric color of three different types of confections (pectin & starch based gummy and hard candy) containing 22% - 40% black raspberry freeze-dried powder. Total phenolics, anthocyanins and polymeric color were measured by dissolving three types of confections in water containing 5% folic acid using a spectrophotometric method according to established protocols. Starch confections retained the highest total phenolics and pectin confections appeared to have the most polymeric color during storage. Total phenolics were relatively stable through the two-month storage at both 4 ºC and room temperature (P>0.05). Anthocyanins decreased during the first two-week storage (P<0.05) and remained stable through the whole storage period at both 4 ºC and room temperature. The polymeric colors of all confections stored at room temperature continually increased (P<0.05) during storage while that confections stored at 4℃ were stable (P>0.05). This study indicates polyphenols had highest stability at 4℃ in starch confections during the two-month storage.
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    Comparison of the storage stability of starch and pectin black raspberry confections
    (2015-03-25) Shi, Menghan; Yael, Vodovotz
    Black raspberries (BRB) are a rich source of bioactive phytochemicals and nutrients, such as anthocyanins and ellagitannins. The phenolic compounds in BRB have drawn much attention recently due to their promising anticancer effect. Physicochemical properties such as texture and water content/activity may influence the phenolic compound stability and sensory acceptance during storage. Therefore, finding suitable food matrix with extended shelf life, higher physicochemical stability and production consistency is important in delivering the bioactive compound from BRB in clinical trials. The objective of this study is to assess the physicochemical stability of two different BRB matrices: Starch and pectin based gummies, under different storage temperature conditions for two months. Total water content, water activity (Aw), texture, and rheological properties were measured for each type of confection during two-month storage under room temperature (RT) and 4 °C. All samples were selected randomly from three batches of scale-up productions with replicates for each test. There was no significant change in elasticity (G’) for pectin stored at both RT and 4 °C. However, for starch gummy, room temperature storage had a significant increase in elasticity compared with fresh sample (P < 0.05). Lower temperature storage overall reduced the water loss in starch confection, showing no significant change even after two months (P > 0.05). However, the total water content of pectin gummy changed significantly during the entire storage time for both conditions (P < 0.05). Starch confection maintained an Aw lower than 0.7 during storage, but the pectin gummy had Aw higher than 0.7, increasing the potential of microbial growth. The results from this study can be used to select storage conditions and suitable food matrix for BRB confections to be used in future human clinical trials.
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    Synthesis of pyridine and pyridinium quinone methide precursors: studies towards the realkylation of aged acetylcholinesterase
    (2015-03-25) Dicken, Rachel; Callam, Christopher
    Acetylcholinesterase (AChE) is an essential enzyme in the human body, which hydrolyzes acetylcholine into choline for biochemical processes. Organophosphorus (OP) nerve-agents such as Sarin, Soman and Tabun are covalent inhibitors of AChE. Following exposure to OPs, inhibited AChE undergoes a subsequent irreversible aging process in which the OP-AChE adduct is de-alkylated (aged) resulting in the accumulation of excess acetylcholine in the central nervous system. Current oxime based pharmaceuticals can only be used to treat the inhibited AChE and are ineffective on the aged AChE. Our research focuses on the design of small molecules that can be used to re-alkylate aged AChE. Previous studies have shown that high energy quinone methides (QM) could potentially reverse the damage done to the active site on aged AChE through a kinetically favored alkylation of a phosphodiester. We have used computational chemistry to guide our synthetic efforts. We have developed methods to synthesize various quinone methide precusors; including pyridine and pyridinium compounds. The synthesis of these compounds and testing of them will be discussed. Mechanistic understanding on the formation of high energy quinone methides and optimization of the reactions for their formation is currently still in progress.
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    Quick to be selfish or quick to be kind? Response time asymmetries in social decision making
    (2015-03-25) Butler, Alison
    Dual-process theories classify a fast, automatic “System I” and a deliberative, controlled “System 2” as distinct mechanisms driving human behavior. Several recent studies have used a classic experimental economics scenario, the public goods game (PGG), to link these systems with participants’ tendency to act cooperatively. This research attempts to measure patterns of intuition and reflection by tracking an individual’s decision time when donating to a common pool. These donations are multiplied by the experimenter and then redistributed equally among the group. Some authors find that cooperative participants make fast decisions, arguing that cooperation is thus intuitive. Meanwhile, other authors find the opposite correlation, claiming that selfishness is intuitive. Our analysis critiques both views by offering an alternative explanation, which is that response time results are driven by the cost of being cooperative. Here we test this hypothesis using data collected from a series of publications on the PGG. These findings provide evidence for our “strength of preference” hypothesis, namely that cooperation is fast when it is low cost and attractive, while cooperation is slow when it is high cost and unattractive. Therefore, we conclude that fast decision times can indicate individual preferences for varying donation efficiencies. These results offer a coherent story to a large body of seemingly incoherent findings.
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    Mindfulness and Mind-Wandering in Older Adults: Implications for Behavioral Performance
    (2015-03-25) Londerée, Allison; Fountain-Zaragoza, Stephanie; Prakash, Ruchika
    Mind-wandering (MW) is an attentional shift from the task at hand to internally generated thoughts. Although common, MW is associated with decreased performance on tasks requiring sustained attention and executive control. In juxtaposition to MW, mindfulness is attending to the present moment nonjudgmentally. Recent studies of both mindfulness disposition and mindfulness training provide evidence for associations between higher levels of mindfulness and both decreased MW and improved cognitive performance. Interestingly, researchers have found that our tendency to mind wander decreases and mindfulness disposition increases with age. Our study further examines the association between mindfulness and MW in an ageing population. Older adults (age 60-74) completed measures of dispositional mindfulness; cognitive control and sustained attention; and MW. The Mindful Attention and Awareness Scale (MAAS) was used as a self-report mindfulness disposition measure. Two computerized tasks were also administered: the Sustained Attention to Response Task (SART), and the word version of the Continuous Performance Task (CPT). MW was assessed using a probe-caught method during both tasks. This study is in progress and preliminary analyses were conducted on approximately half of the desired total sample. It is hypothesized that dispositional mindfulness will be negatively related to MW episodes and reaction times to MW probes; preliminary analyses found these relationships to be significant in the CPT task. In addition, we predict MW will be associated with decreased accuracy and greater variability of reaction time; preliminary analysis revealed a marginally significant correlation between sensitivity scores and proportion of reported off-task thought during the CPT task. Lastly, higher levels of dispositional mindfulness are expected to accompany increased accuracy and lower variability of reaction time; preliminary analyses found a significant association between mindfulness and sensitivity in the SART and variability of reaction time in both tasks.
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    Influence of a Maternal Dietary Yeast Supplement on Immunoglobulin Concentrations in Foals from Birth to Four Months of Age
    (2015-03-25) Reddish, John Mark; Cole, Kimberly; Leimbach, Rachel; Cole, Kimberly
    Previous studies in multiple species have shown that maternal diet can affect immunoglobulin concentrations in their resulting offspring. To our knowledge, the effect of maternal dietary yeast supplementation on immunoglobulin levels in foals has not been studied. In this study eight Quarter Horse mares (14.5 ± 7.5 yr) were randomly assigned to one of two groups: Yeast or Control. All mares received a control diet of 0.5% BW of a 16% CP pelleted concentrate with water and mixed grass hay ad libitum. Mares in the yeast treatment group also received 1g/45.4 kg of BW/d of a live culture of Saccharomyces cerevisiae from 250 d of gestation to 90 d post-foaling. All mares were vaccinated at d 300 of gestation against Eastern and Western equine encephalomyelitis, equine rhinopneumonitis (EHV-1 and EHV-4), equine influenza (type A2), tetanus and West Nile virus. Blood samples were collected from the foals via jugular venipuncture immediately after parturition (d 0), at 12 and 24 hr and 30, 60, 90, and 120 d post-foaling. Sera samples were analyzed for total IgG including IgGa, IgGb, and IgG(T), as well as IgA, IgM, and IgE concentrations using commercial ELISA kits. Data were analyzed using PROC MIXED of SAS and a p-value of ≤ 0.05 was considered statistically significant. Supplementing the maternal diet with live yeast did not influence foal IgGa, IgGb, IgA, IgM, or IgE concentrations. However, IgG(T) concentrations were significantly higher (P = 0.0063) on d 60 post-foaling in foals born from mares fed the yeast supplement compared to controls. Overall, maternal dietary yeast supplementation during late gestation and early lactation did not influence immunoglobulin concentrations in their foals.
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    Social capital and high-risk sexual behaviors in agricultural plantation residents in Tanzania
    (2015-03-25) Wiles, Melissa; Norris, Alison
    Human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs) are leading causes of mortality and morbidity in many countries of the world. The practice of having concurrent sexual partners is an important risk factor for STI transmission. Social capital is a target area for improving sexual health. Social capital describes the ways in which individuals are connected to resources that can influence their behaviors, and provides methods of coping with stressors. Previous studies have yielded contradicting findings about the effects social capital has on sexual health behaviors and STI prevalence. Our study aims to investigate social factors, namely social capital and support, which may play a role in reducing STI prevalence and the practice of concurrent partnerships. We conducted secondary data analysis from a study of 623 agricultural plantation residents in Tanzania to assess this relationship, hypothesizing that higher social capital would be associated with less concurrent sexual partnerships and less prevalent STIs (including HIV, HSV-2, and syphilis). We used principal component analysis to convert seven variables related to social capital into a smaller set of uncorrelated factors. The resultant 3 factors – reciprocity, trust, and decision-making – were used as predictors in multiple regression models for both concurrent sexual partnerships and prevalent STI, stratified by gender. We found that having positive social capital in the ‘network’ dimension was associated with being less likely to have concurrent sexual partnerships among women (AOR=0.47, 95% CI 0.23-0.87) and that having positive social capital in decision making was associated with being more likely to have a prevalent STI among men (AOR=2.13, 95% CI 1.02-4.52). Transactional sex was significantly associated with both outcomes in women. Suggested initiatives for improvement of sexual health include creating community groups that encourage unity and fellowship among women in order to decrease the prevalence of risky sexual behaviors. More research is necessary to create a uniform definition of social capital that can be applied in future studies that examine the relationship between this concept and sexual health.
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    The Churches of Kythera
    (2015-03-25) Crum, Matthew; Gregory, Timothy
    This study focuses on the geographic significance of churches constructed on the Greek island of Kythera between the 10th century and mid-16th century. Close analysis of the churches in the northern half of the island shows that these structures, along with their spiritual functions, were often used in tandem with defensive structures or as defensive structures themselves. These religious buildings performed the role of watchtowers, or viglae. This conclusion is based on the geographic relationships between the churches and the villages, roads, and coasts, as well as by the architectural features of several of these sites. This thesis also argues that the churches and the saints associated with them provided divine protection for the Kytheran people. This is made evident through studying the dedications of these churches, as well as the frescoes on their walls and the written narrative sources. Finally, I suggest some avenues for future research both in southern Kythera and in the southern Peloponnese, and how these areas can be reanalyzed in light of my research.
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    Understanding Pragmatic Language Development: Comparing Adults and Children
    (2015-03-25) Martinez, Liana; Grinstead, John; Ellawadi, Allison
    This study addresses the connection between children’s developing knowledge of prosody – their use of pitch when producing language – and pragmatics – their use of language in plausible ways, to convey and comprehend meaning, whether spoken or unspoken. Previous studies on this topic show that adult comprehension of the quantifier ‘some’ is different when ‘some’ is produced with what we refer to as a “pitch accent” or sudden variation in pitch that indicates a change in meaning. While children have been shown to grasp this difference in meaning, previous work suggests that they attend to word duration and not pitch in an experiment that compared phonetic variants of some. Further, it has been proposed (Snow 2006) that prosodic development parallels morphosyntactic development. In my project, I investigate two questions: 1) at what point do children come to have adult-like knowledge of the pragmatic-prosody interaction in their use of phonetic variants of the quantifier some? and 2) is there a relationship between morphosyntactic development and pitch accent perception? To answer these questions, I test a sample of typically-developing, monolingual English-speakers. The measure of prosodic and pragmatic knowledge is a video recorded Truth Value Judgment Task (TVJT), which provides a measure of accuracy and a measure of complexity (reaction time). Children were also given a standardized test of language, which includes a measure of morphosyntactic development, which I compare to their interpretation accuracy and reaction time results from the TVJT. Results suggest that our school-aged children (5-8 year-olds) behave similarly to preschool children in not grasping the meaning of pitch accent, and there is so far no discernable relationship between morphosyntactic development and measures of prosody/pragmatics. However, our results show that the faster the reaction time with some, the better children do better at inflection.
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    The Effects of EPA+DHA Supplements on CRP Levels in Patients with Chronic Venous Leg Ulcers: A Pilot Study in Older Adults
    (2015-03-25) Sawyer, Jacqueline; McDaniel, Jodi
    Chronic venous leg ulcers (CVLUs) affect approximately 1% of the U.S. population and nearly 4% of people over age 65 years. The healthcare costs (> 1 billion USD annually) associated with CVLUs and their increasing prevalence support the need for new interventions to facilitate healing. CVLU pathogenesis involves unremitting inflammation. Polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have inflammation resolving effects. This study’s purpose was to compare plasma levels of high-sensitivity C-reactive protein (hs-CRP), an inflammation biomarker, over an 8-week period between CVLU participants in an Active Group receiving EPA+DHA supplements and those in a Placebo Group. The sample consisted of 17 CVLU patients in Central Ohio. Dr. William Harris’s theory regarding the inflammation-resolving mechanisms of EPA+DHA guided the study design. Participants were randomly assigned to the Control Group (mineral oil: 5cc/d) or Active Group (EPA+DHA: 2.8 g/d). Plasma samples were collected at baseline and after 8 weeks to quantify hs-CRP levels using Cayman’s CRP enzyme immunoassay kit. Sociodemographic data were collected. On average, the group age was 62 ±12.51 years and the body mass index (BMI) was 41.94 ± 12.78 kg/m2 (severe obesity). The majority of participants self-reported White as their race (82%) and an income of < 29,999 USD/year (68%). Though there was no significant difference in hs-CRP change scores from 0 to 8 weeks between the Placebo Group (0.02 ± 1.86 mg/L) and the Active Group (-0.21 ± 0.50 mg/L) (p=.75), a larger proportion of Active Group participants demonstrated a reduction in hs-CRP levels by 8 weeks (67%) compared to the Placebo Group (50%). The findings suggest that EPA/DHA supplementation may reduce inflammation and promote CVLU healing, but further research is needed. The known association between high BMIs and elevated inflammation warrant the need for nursing interventions that promote healthy weights to improve CVLU healing.
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    Linkages between physical activity and nightly salivary cortisol in a pilot study of adolescents
    (2015-03-25) Gresham, Louis; Ford, Jodi
    The purpose of this study was to explore associations between the frequency of moderate/strenuous physical activity among adolescents and their averaged nightly cortisol level collected over a one-week time period. Prior research has supported that physical activity can be beneficial for reducing psychosocial stress. However, studies have also found significant associations between high intensity exercise and elevated salivary cortisol levels– a physiologic stress marker. Secondary data were analyzed from a pilot study of 22 adolescents recruited from one high income and one low-income census tract located in an urban area in the Midwest. Data were collected via trained interviewers over a one-week time frame in which youth completed an in-home survey and self-collected nightly saliva samples for cortisol on nights 1-6. Two survey questions were asked related to the frequency of moderate and strenuous physical activity over the prior week (range 0-10). The frequencies were summed to create a total score of moderate/strenuous physical activity over the prior week and dichotomized to compare adolescents who engaged in moderate/strenuous physical activity 6-10 per week to those who engaged 0-5 times per week. Nightly cortisol levels were assessed via ELISA assay and the week’s values were averaged and logged due to the skewed distribution. Spearman rho correlation between the total score of moderate/strenuous physical activity and the averaged nightly cortisol was modest (0.37, p<0.09) and the ANOVA bivariate analysis indicated adolescents who engaged in moderate/strenuous physical activity 6-10 per week had higher mean cortisol values compared to their less active peers (p<0.05). Longitudinal research on the effects of frequent/moderate physical activity on adolescents’ cortisol levels and subsequent health outcomes is needed.
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    Manipulating Attitude Change Toward Michigan Fans by Using Facial Expressions in Evaluative Conditioning
    (2015-03-25) Fridstein, Allie; Fazio, Russell
    This experiment examined the role of implicit misattribution in an evaluative conditioning (EC) procedure aimed at modifying attitudes toward outgroup members (Michigan fans). EC is attitude change toward an object (conditioned stimulus, CS) due to its pairing with another valenced object (unconditioned stimulus, US). The present research tests the Implicit Misattribution Model (IMM; Jones, Fazio, & Olson, 2009) by examining facial expressions as a factor influencing EC. The IMM proposes that EC occurs when viewers unconsciously misattribute their attitude towards the US to the CS and any factor that promotes confusability regarding the source of the activated evaluation fosters such implicit misattribution. We predicted that participants who view smiling Michigan fans as CS will develop less negative implicitly measured attitudes towards Michigan due to increased source confusability, relative to participants who view frowning Michigan fans as CS. After undergoing the EC procedure, participants completed the personalized Implicit Association Test (pIAT), which tested how easily they associated Michigan with liked versus disliked objects. Three conditions varied with respect to the pairings presented during surveillance: high source confusability, which showed smiling Michigan fans with positive US; low source confusability, which showed frowning Michigan fans with positive US; and control, which did not pair Michigan fans with particular US. Those in the high source confusability condition displayed less implicitly-measured negative attitudes towards Michigan than participants in the other two conditions. This provides support for the IMM of EC. Applying this knowledge could potentially lower discrimination and prejudice toward outgroup members.
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    Executive Function’s Role in Children’s Perception of Nonnative Speech
    (2015-03-25) Hill, Angela; Holt, Rachael
    Large individual differences in spoken word recognition have been observed in children with hearing loss and with normal hearing. Executive functions account for some of this variability (Beer, Kronenberger, & Pisoni, 2011; Lalonde & Holt, 2014). Individual performance differences are also evident when listeners are presented with nonnative speech. This study examined the influence of executive function on children’s nonnative speech perception. Eighty-four 5- to 7-year-old monolingual English-speaking children were presented with 60 English sentences produced by either a native English or Mandarin-accented talker (Van Engen et al., 2010) embedded in multi-talker babble at +8 dB signal-to-noise ratio. For 30 sentences, the final (target) word was highly predictive from sentence context and for the other 30 it was not; the same final words appeared in both predictability conditions. Sentence context facilitated target word recognition similarly for native and nonnative talkers. Children with better inhibition, as assessed by the Behavior Rating Inventory of Executive Function (Gioia, Isquith, Guy, & Kenworthy, 2000), had better perception of nonnative speech than those with poor inhibition. Stronger executive functions appear to support word recognition under adverse listening conditions, including both those stemming from the listener (e.g., hearing loss) or, as shown here, the talker (e.g., nonnative speech).
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    Design of Leading Edge Vortex Flaps for Delta Wings at Low Speeds
    (2015-03-25) Wagner, Benjamin; Whitfield, Clifford
    Small unmanned aerial vehicles (UAVs) have become increasingly important in the role of tactical reconnaissance. Frontline troops rely on the ability to easily deploy UAVs from any position in order to collect time sensitive intelligence. One of the primary criteria for small UAVs is that of portability. In order to address this need, it has been proposed to design a UAV with a foldable delta wing made of a flexible material. However, delta wings typically suffer from decreased aerodynamic efficiency which is the ratio of the lift created to the drag produced. Poor performance in this regard is especially pronounced at low speeds. Since range is directly proportional to the maximum achievable aerodynamic efficiency, a delta wing equipped UAV would need to expend more propulsive energy to accomplish a given mission in comparison to conventional designs. A potential solution exists in the form of Leading Edge Vortex Flaps (LEVF). Essentially a flap-like control surface attached to the wings leading edge, such devices have been shown to improve aerodynamic efficiency by as much as 20 percent on conventional delta wing aircraft. The objective of this research was to determine an effective flap design with the goal of achieving the same aerodynamic improvements for flexible delta wings at low speeds. A secondary objective relating to the potential use of LEVF devices as a means of vehicle control was also investigated. Using Computational Fluid Dynamic (CFD), two and three dimensional analysis was performed on 30° and 60° delta wings in combination with various LEVF geometries. Effort was given to refining the geometry of a fully three-dimensional flap model as well as to determining the primary flow mechanisms that govern the creation of lift, drag, and ultimately aerodynamic efficiency. The results indicated that, at the low velocities tested, LEVF devices could improve the Aerodynamic Efficiency of a 30° delta wing by 4 percent and a 60° delta wing by as much as 10 percent. While a preliminary investigation into the potential for using LEVF devices as a means of vehicle control produced some encouraging results, additional work would be needed in order to make any definitive conclusions.
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    Development of an Active Flight Envelope Warning Method for General Aviation Aircraft
    (2015-03-25) Scherer, Steven; Whitfield, Clifford
    Loss of control incidents in flight are the primary cause of fatal general aviation accidents. By definition, a loss of control event is a preventable occurrence where a pilot should have maintained or regained control of their aircraft. Giving a pilot sufficient warning to correct dangerous situations is crucial in preventing loss of control. Existing warning methods are based on physical margins of aircraft limitations and do not directly consider how much time is left to act before loss of control. This research focuses on the development of a method that uses real-time inertial and aerodynamic data to calculate and improve warnings of flight envelope limitations. X-Plane 10, a realistic flight simulator, has been used to simulate the flight of a Cessna 172, a common general aviation aircraft. The flight model of X-Plane has been compared to empirical data with favorable results thus far, indicating X-Plane is a reasonable platform on which to investigate an active warning system. Development of a software plugin for the warning system is underway. The plugin uses live flight model and aircraft data from X-Plane to consider proximity to a potential loss of control event before issuing a warning. Preliminary results suggest significant (>1 second) improvement over traditional stall warnings. With careful consideration of the physical state of the aircraft, the system is meant to always give the pilot at least 2 or 3 seconds to correctly react to a dangerous situation. This type of "constant time" warning is a novel approach to preventing loss of control and offers distinct advantages over more traditional methods, which can leave pilots with very little time to react. A proof-of-concept for this warning technique opens possibilities of more capable yet less costly loss of control mitigation systems that can greatly reduce general aviation fatalities.
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    Prevalence and Demographics of Vitamin D Deficiency in Children with Asthma
    (2015-03-25) Messick, Emily; Gracious, Barbara
    Vitamin D promotes calcium and phosphorus absorption from the intestinal tract and exerts anti-inflammatory effects on the immune system. Low vitamin D levels raise risk for autoimmune diseases. Vitamin D deficiency also causes rickets, osteopenia, osteoporosis, and fractures. Since few foods contain it, we are reliant on sun exposure for cutaneous synthesis of vitamin D. Small studies have explored the relationship between asthma and vitamin D levels, but larger controlled studies are needed. This study examines the relationship between demographics and self-reported sun exposure/dairy intake with 25-OH vitamin D levels in asthmatic children, as part of a larger study including immune function. Sixty-four children ages 8-17 taking inhaled steroid maintenance treatment were recruited through asthma/allergy clinics at Nationwide Children's Hospital. Exclusion criteria included substance dependence, metabolic bone/malabsorption disease, BMI > 35, vitamin D supplementation, recent oral steroid treatment, or mineral oil/thiazide diuretic use. Participants were administered a modified vitamin D questionnaire assessing sun exposure, dairy intake, and supplementation usage, and had blood drawn to determine 25-OH vitamin D level. Of 64 participants, 16 were vitamin D deficient (<20 ng/ml; 25%). These 16 were: 69% > age 11, 69% African American, 31% overweight/obese, 63% not receiving a suntan within a year, and average dairy consumption 1.5 (±1.75) daily servings. Those not deficient were: 33% > age of 11, 27% African American, 15% overweight/obese, 33% not receiving a suntan within a year, and average dairy consumption 1.54(±1.54) daily servings. Results show an increased risk for vitamin D deficiency with higher BMI, darker skin, age, and lower sun exposure. Physicians of asthmatic children of all races/ethnicities can provide counseling that limited safe sun exposure (20” daily to arms and legs), including during physical activity necessary for a healthy lifestyle, helps prevent vitamin D deficiency.
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    Optimizing Frequency Channels in Cochlear Implants
    (2015-03-25) Boyce, Lauren; Holt, Rachael Frush; Nittrouer, Susan; Moberly, Aaron; Moberly, Aaron; Holt, Rachael Frush
    Cochlear implants (CIs) are devices used by individuals with hearing loss to improve communication through the use of an electrode array that directly stimulates the auditory nerve. Existing signal processing strategies utilize a logarithmic frequency-to-electrode allocation, mimicking the representation of frequencies along the basilar membrane (high frequencies at the base and low frequencies at the apex). These strategies support some degree of open-set speech recognition for CI users; however, average speech recognition remains well below what normal-hearing adults are capable of. To enhance speech recognition in adult CI users, this study examined one promising alternative to the standard logarithmic frequency-to-electrode allocation maps. The frequency-to-electrode allocation maps were modified to provide more refined representations of the first two (and most important) vowel formant frequencies (energy peaks in vowels that are critical to speech perception). Twelve participants were tested using two different CI maps: one based on existing clinical frequency-to-electrode allocation strategies (Standard) and one designed to improve the resolution of the first two formants, which should especially enhance vowel recognition (Speech). Alternating between these maps, participants listened to and repeated three kinds of stimulus materials: (1) highly meaningful five-word sentences, (2) syntactically correct but not meaningful four-word sentences, and (3) phonetically balanced consonant-vowel-consonant words in isolation. Analyses revealed that some participants benefitted from the Speech strategy. Moreover, an improvement in vowel recognition in words strongly predicted an improvement in recognition of words in sentences. These findings suggest that optimizing the representation of the first two formants enhances speech recognition for CI users. Future efforts should focus on better representing this speech-specific information in modern-day signal processing strategies.
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    Analyzing Semantic-Pragmatic Processing of Scalar Implicatures in Typically-Developing Children
    (2015-03-25) Selio, Emily; Grinstead, John
    This research examines the presence of the quantifier “some” in English speech. Past research indicates that both semantics and pragmatics, or the context of the situation dictate the meaning of the word. With this particular quantifier it is important to identify the variations in pitch accent that will be controlled for within this experiment. The first vowel-reduced sm implies an existential or “logical” interpretation of the implicature. This can be interpreted as a “some and maybe all” meaning. Another, spoken with a L+H* pitch accent, SOME, has a pragmatically influenced “some, but not all” implicature. The final variation, some, holds an intermediate status, has a full vowel, unlike sm, but lacks a pitch accent, like SOME, and may or may not occur with an implicature. Our question that does not appear to have been asked before is what happens when an existential quantifier, such as some, marked with a L+H* pitch accent, occurs in an implicature-cancelling downward-entailing environment, such as the antecedent of a conditional sentence. Does the grammatical context “win” and cancel the implicature, or does the prosodic contour “win” and generate the implicature? Further, given the knowledge that preschool children pay attention to an implicatures duration rather than pitch, at which age do children become adult like? To answer this question we used a Truth Value Judgment Task in a between-subjects design with six groups (3 groups of adults, n=113 ; and 3 groups of children n=92 , age range=4;0–8;8, mean age=71 months, SD=12.39 months). Tentative conclusions are that adult interpretations are influenced by both pitch accent and grammatical context. Children appear to largely disregard pitch and attend to duration.
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    Numerical Magnitude Representations Explain the "Learning Gap"
    (2015-03-25) Wang, Yiwan; Opfer, John
    The mathematical “learning gap” between Chinese and American students exists since a very young age. Previous studies have focused on the correlations between children’s arithmetic performance and their general intelligence, symbolic numerical proficiency (e.g., the numerical number “4”), or non-symbolic numerical proficiency (e.g., four apples) within a single culture. The current study has two hypotheses: 1) Chinese preschoolers perform better in math than American preschoolers; and 2) Chinese children’s outperformance is because of their higher symbolic numerical proficiency. We sampled 80 children, 40 native to China and 40 native to America. The arithmetic performance was measured by the 1-minute speed addition task; the general intelligence was predicted by the digit coding task; and either of the numerical proficiencies (symbolic or non-symbolic) was measured by three different tasks: the number-line spatial task, the number comparison task, and the approximate addition task. In support of our hypotheses, Chinese children significantly outperformed American children in general mathematics, and symbolic numerical proficiency, rather than non-symbolic numerical proficiency or intelligence, mediated the effect of nation on children’s arithmetic performance. Spatial numerical proficiency also played an important role in producing cross-national differences in arithmetic ability. These results indicated that implementing a combination of symbolic and spatial numerical activities in early development is likely to prove more effectiveness in closing the “learning gap” between Chinese children and American children.