Immersion versus Engagement Strategies: Examining the Effects on Conversational Competence amongst Korean Students in an Intensive English Program

This study seeks to examine the effect that immersion versus engagement strategies has on the language growth and efficacy of Korean EFL students learning to speak conversational English in an Intensive English Program (IEP) at an American university. This study utilized quantitative research techniques to answer the various questions that arise in regard to the effectiveness of immersion in an intensive English program. Eight Korean students were selected to partake in the research with four currently attending the IEP program and four having since graduated from the same IEP program. The study was conducted through interviews and questionnaires to examine the effectiveness of immersion strategies within the IEP program. The study found that although some engagement strategies remained somewhat effective for Koreans learning conversational English, the students preferred immersion. The Korean students noted that their interaction with native English speakers in environments where they were immersed in English such as in living situations or extracurricular programs increased their retention of English over activities done in the classroom

Management effects on the environmental footprint of swine production

Livestock production in general is a very small contributor to GHG emissions. However, swine producers will continually be faced with a series of challenges to minimize the environmental impact of swine production. The main objectives of the the studies in this thesis were to evaluate the effects of reducing dietary CP with the supplementation of synthetic AA and the effects of feeding diets with or without antibiotics on manure generation and excretion of N and C. In Exp. 1, thirty-two barrows were used in a metabolism study to evaluate the effect of feeding reduced CP, amino acid (AA) supplemented diets on nutrient excretion. Pigs were assigned to one of four dietary treatments: 1) Control: Corn-SBM-DDGS diets with no synthetic AA, 2) 1X reduction in CP, 3) 2X reduction in CP, and 4) 3X reduction in CP. Diet 4 was balanced on the 7th limiting AA, phenylalanine. Diets 2 and 3 were then formulated to have a stepwise reduction in CP between Diets 1 and 4. Diets 2-4 were supplemented with synthetic amino acids as needed to meet amino acid needs based on NRC 2012 AA minimum ratios for the 7 age phases tested. Low-CP AA supplemented diets significantly reduce N excretion by up to 45%. In addition, VFA concentrations were reduced between 9-17% when dietary CP content was reduced up to 3X levels. Overall fecal C excreted (g/pig/d) was greatest for the lowest CP (3X), largely due to the % C digested being the lowest for that diet. Both DE and ME, were linearly (P \u3c 0.0001) decreased by approximately 6 and 5% respectively with increasing reductions in dietary CP. In Exp. 2, seven hundred twenty-three pigs were placed into eleven identical, environmentally controlled rooms for a wean-to-finish study. Pigs were allotted to one of two dietary treatments: 1) Control: Corn-SBM-DDGS diets with Antibiotics, and 2) Antibiotic Free; treatment 1 less the antibiotics but with alternative supplements. Diets were fed in nine dietary phases. There was a tendency for greater final BW and BW gain per manure pit when pigs were fed the control antibiotic treatment. No significant differences were observed between the two dietary treatments for manure volume (L), manure volume per kg BW gain, DM (g/kg BW gain), N (g/kg BW gain), and AmmN (g/kg BW gain). Manure pH tended to be lower for pigs fed the antibiotic free diet (P \u3c 0.06) compared to the control diet. There were no differences observed for manure total C (kg), manure C per kg BW gain, manure C g/pig/d, and manure C g/pig wean-to-finish. In summary, Exp. 1 low CP diets with synthetic AA supplementation result in lower DE and ME values and C digestibility for the lowest CP diets, but significantly reduce N and VFA excretions. In Exp. 2, the antibiotic free diets had similar manure nutrient excretion and generation with lower manure pH which may affect transformation of N2O during manure land application. The adoption of technologies like these evaluated in this thesis will be of the utmost importance in remaining proactive in finding a way to meet the demands of a growing world population in a manner that is cost effective for the producer, while being environmentally sustainable

Contribution of Far Field Effects of Cortical tDCS in the Cerebellum to Learning in an Object Detection Paradigm

Transcranial direct current stimulation (tDCS) has been shown to enhance many cognitive and motor functions, and has been used in many areas, including rehabilitation of speech after stroke, cognitive enhancement, and treatment of mental illness. Our lab has demonstrated that, paired with training, anodal tDCS over electrode site F10 as well as cathodal tDCS over site T5 both increased the ability to detect hidden objects in a complex visual environment in a discovery learning paradigm. Stimulation of F10 has further been shown to enhance perceptual sensitivity selectively, without a change to response bias, and this effect was further enhanced when images presented during training were repeated in a post-training, post-stimulation test (Clark et al., 2012; Coffman et al., 2012; Falcone et al., 2012). Furthermore, this increased ability to detect hidden objects persisted for at least 24 hours Falcone et al., 2012). It has also been shown to increase measures of attention, using the Attention Network Task (ANT; Fan, 2002). Specifically, alerting network scores were increased in participants receiving active anode F10 stimulation compared to sham. Since both F10 anode as well as T5 cathode stimulation both resulted in increased learning the object detection task, potential additive effects were inferred, and an F10 anode/T5 cathode electrode montage was investigated. Surprisingly, this montage had an effect of about half of the other two montages (F10 anode/shoulder, T5 cathode/shoulder). Finite element current modeling studies were conducted to investigate more precisely where in the brain the electricity is traveling during these different stimulation protocols. Results suggested that both cephalic/extra-cephalic electrode placements exhibited far-field effects in subcortical areas, bilateral temporal poles, as well as in the cerebellum, albeit with opposite polarities. During F10 anode/shoulder cathode stimulation, a negative electrical field effect was seen in the cerebellum. During T5 cathode/shoulder anode stimulation, the opposite was true: there was a positive field effect in the cerebellum. However, the montage with a bi-cephalic placement showed no such effect in the cerebellum. Based on these modeling data, the difficulty of reaching subcortical areas with tDCS, and the evidence that the cerebellum is not only involved in motor behavior, but cognition as well, the cerebellum was chosen for direct stimulation with tDCS and was hypothesized to be contributing to the learning and attention effects reported in previous studies. Thirty-six participants received either anodal, cathodal, or sham stimulation of the medial posterior cerebellum during training to detect hidden objects in a complex visual environment. Measures of learning, signal detection, and interactions with stimulus type were investigated. Regression models were also built to investigate the contribution of each electrode placement in the two different montages. Measures of attention assessed with the ANT were also investigated. To our surprise, neither anodal nor cathodal stimulation of the cerebellum led to an increase in learning compared to sham stimulation. Furthermore, no effects were observed between groups on signal detection measures, nor was there an effect of group on stimulus type, all of which had previously been reported with F10 stimulation. Likewise, neither anode nor cathode stimulation led to an improvement on measures of attention compared to sham. The conclusion is that the cerebellum does not appear to be involved in the network contributing to learning and performing the object detection task. Although there were no direct effects of anodal or cathodal tDCS of the cerebellum on learning or attention, this study is an important step in elucidating the network involved in the robust finding of increased ability to detect hidden objects after administration of tDCS paired with training, as it rules out one potential contributor

Modernized Approach For Generating Micro-Layering And Macro-Heterogeneous Structures In Porous Media For Use In Transmitted-Light Method Flow Visualization Experiments

Image capturing in flow experiments has been used for fluid mechanics research since the early 1970s. Interactions of fluid flow between the vadose zone and permanent water table are of great interest to researchers because this zone is responsible for all recharge waters, pollutant transport and even irrigation efficiency for agriculture. Griffith, et al. (2011) developed an approach where constructed reproducible “geologically realistic” sand configurations are deposited in sand-filled experimental chambers or cells for light-transmitted flow visualization experiments. This method creates reproducible, reverse graded, layered (stratified) thin-slab sand chambers for visualizing multiphase flow through porous media. Reverse-graded stratification of sand chambers mimic many naturally occurring sedimentary deposits. Sand-filled cells use light as nonintrusive tools for measuring water saturation in two-dimensions (2-D). Homogeneous and heterogeneous sand configurations can be produced to visualize the complex physics of the unsaturated zone. The experimental procedure developed by Griffith, et al. (2011) was designed using now outdated and obsolete equipment. We have modernized this approach with new PARKER daedal linear actuator and programed projects/code for multiple configurations. We have also updated the camera with new software and image processing software. Modernization of transmitted-light source, robotic equipment, redesigned experimental chambers, and newly developed analytical procedures have greatly reduced time and cost per experiment. We have demonstrated the functionality of the new equipment to generate micro-layers and macro-heterogeneous sand-filled chambers

Multi-channel Unbounded Optical Communication through Modulation of LED Lighting

With the ever-increasing demand for more mobile bandwidth and higher data transfer rates, expansion into the Terahertz spectral range is inevitable. Modern Wi-Fi technologies (2.4 GHz and 5 GHz) theoretically support data rates up to only a few Gbps. A newly emerging technology, Light Fidelity (Li-Fi) provides communication with potentially Tbps rates through LED lighting. One unique benefit of Li-Fi is that it can be used simultaneously for illumination and high-speed, secure (line-of-sight) communication. Li-Fi would be best utilized in conjunction with Wi-Fi and mobile LTE networks as it is more suitable for one-way short range communication due to relatively high power needed for the lighting source. Combining wavelength division multiplexing (WDM) and frequency division multiplexing (FDM), this project focused on realizing a high-speed optical communication link for a cost comparable to a Wi-Fi router. By processing data using a microcontroller with an Ethernet connection, a 52 Mbps link was demonstrated [three frequencies (n=3) for each of the primary colors (Red, Green, Blue) — a total of nine (3n) channels]. Data transfer rates up to 486 Mbps were shown to be viable with this three-color three-frequency system. Integrating data processing and multiplexing/demultiplexing functionalities on a single chip would eliminate the bottleneck imposed by the microcontroller clock speed. Additionally, this Li-Fi system can be scaled up by adding a yellow LED, which would also improve the quality of white light, and by adding more carrier frequencies. With these improvements, Li-Fi stands to provide high-speed communications through LED lighting.https://scholarscompass.vcu.edu/capstone/1110/thumbnail.jp