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I worked on the human-machine interface to improve human physical capability. This work was done in the Human Oriented Robotics and Control Lab (HORC) towards the creation of an advanced, EMG-controlled exoskeleton. The project was new, and any work on the human- machine interface needs the physical interface itself. So I designed and fabricated a human-robot coupling device with a novel safety feature. The validation testing of this coupling proved very successful, and the device was granted a provisional patent as well as published to facilitate its spread to other human-machine interface applications, where it could be of major benefit. I then employed this coupling in experimentation towards understanding impedance, with the end goal being the creation of an EMG-based impedance exoskeleton control system. I modified a previously established robot-to-human perturbation method for use in my novel, three- dimensional (3D) impedance measurement experiment. Upon execution of this experiment, I was able to successfully characterize passive, static human arm stiffness in 3D, and in doing so validated the aforementioned method. This establishes an important foundation for promising future work on understanding impedance and the creation of the proposed control scheme, thereby furthering the field of human-robot interaction.
ContributorsO'Neill, Gerald D. (Author) / Artemiadis, Panagiotis (Thesis director) / Santello, Marco (Committee member) / Santos, Veronica (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2013-05
Description
In 1937 Canadian neurosurgeon Wilder Penfield made the first to attempt to map the sensorimotor cortex of the human brain in his paper entitled Somatic Motor and Sensory Representation in the Cerebral Cortex of Man as Studied by Electrical Stimulation. While analogous experimentation had been carried out previously using animal subjects, Penfield sought to understand the delicate and complex neuronal pathways that served as the hidden control mechanisms for human activity. The motor homunculus that followed from his findings has been widely accepted as the standard model for the relative spatial representation of the functionality of the motor cortex, and has been virtually unaltered since its inception. While Penfield took measures to collect cortical data in a manner as accurately as scientifically possible for the time period, his original model is deserving of further analysis using modern techniques. This study uses functional magnetic resonance imaging (fMRI) to quantitatively determine motor function volumes and spatial relationships for four motor tasks: toe, finger, eyebrow, and tongue. Although Penfield's general representation of the superior-to-inferior spatial distribution of the motor cortex was replicated with reasonable accuracy, relative mean task volumes seem to differ from Penfield's original model. The data was first analyzed in each individual patient's native anatomical space for task comparison within a single subject. The volumes of the motor cortex devoted to the eyebrow and toe tasks, which comprise only small portions of the Penfield homunculus, are shown to be relatively large in their fMRI representation compared to finger and tongue. However, these tasks have large deviation values, indicating a lack of consistency in task volume size among patients. Behaviorally, toe movement may include whole foot movement in some individuals, and eyebrows may include face movement, causing distributions that are more widespread. The data was then analyzed in the Montreal Neurological Institute (MNI) space, which is mathematically normalized for task comparison between different subjects. Tongue and finger tasks were the largest in volume, much like Penfield's model. However, they also had substantial deviation, again indicating task volume size inconsistencies. Since the Penfield model is only a qualitative spatial evaluation of motor function along the precentral gyrus, numerical deviation from the model cannot necessarily be quantified. Hence, the results of this study can be interpreted standalone without a current comparison. While future research will serve to further validate these distances and volumes, this quantitative model of the functionality of the motor cortex will be of great utility for future neurological research and during preoperative evaluations of neurosurgical patients.
ContributorsOland, Gabriel Lee (Author) / Frakes, David (Thesis director) / Santello, Marco (Committee member) / Baxter, Leslie (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
Description
Fat-stigma has become a popular topic of research in recent years as obesity and Western ideals have made their way around the globe. Previous studies have found that the internalization and expression of body norms can vary dramatically depending on location, gender, and many other cultural factors. Differing levels of body satisfaction have been linked to the internalization of these norms, and the development of low body esteem can result in many physical and emotional problems. Although there is an abundance of research on the topic of fat-stigma, few studies have investigated the related, but seemingly independent, topic of the ideal thin body. Furthermore, limited research has looked directly at body size stereotypes in Guatemala, and those that have, focused solely on Guatemala City. Furthermore, no previous cross-cultural analyses were found comparing body norms among US and rural Guatemalan adolescents. By surveying 9-10 year old students in Acatenango, Guatemala and Phoenix, Arizona, this study compared the preferences as well as stereotypes for average, thin, and fat body sizes in these two contexts. The results of this study illustrate a contrast between a fat-negative and a thin-negative culture, and highlight the complexity of the emergence of body norms around the world. We find that, in contrast to previous studies, neither the western ideal thin body nor obesity stereotypes have been internalized in Acatenango. Furthermore, negative evaluations of fat bodies and positive evaluations of thin bodies seem to be made independently of each other. Americans had a much higher prejudice against fat children and were more likely to be thin-positive (OR=1.997), while Guatemalans were more likely to be thin-negative. On average, the American students were much more polarized in their judgments on different body sizes, and experienced greater levels of body dissatisfaction. Finally, American students favored an ideal figure over one size smaller than Guatemalan students. Results suggest that there are still rural communities that have not been entirely affected by the spread of western body norms.
ContributorsCole, Dawn Michelle (Author) / Maupin, Jonathan (Thesis director) / Hruschka, Daniel (Committee member) / Barrett, The Honors College (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2013-12
Description
Africa is the area of the largest economic water scarcity on earth, with multiple countries, political systems, and geographies involved. Additionally, water scarcity affects more countries in sub-Saharan African than anywhere else on earth, with consequences like waterborne diseases, loss of agricultural development, educational setbacks, and security threats. This thesis synthesizes data on the diverse geographies and politics involved in building a sustainable African water system. It presents historical and present technologies, costs, and problems implementing sustainable potable water solutions, and suggests regional differences and individualized solutions, pointing out advantages and disadvantages of damming, boreholes, open wells, open-source water, and sewer systems. It goes on to discuss grant programs for water and wastewater solutions and technologies. Finally it addresses two divergent, yet equally important data models for African water planning, combining their contributions in order to gain insight into the problem that neither alone can. The research overlaps aquifer and demographic data to see where water should be a priority in Africa. The author finds that hydrology as well as demographic data, when combined, point to the greatest water need in the Sahel. However, many growing cities are situated in areas with high aquifer levels making borehole technology some of the most economical as well as sustainable water sourcing. Recommendations include cultural humility, attention to political and environmental consequences of solutions, and cost-effective ways of addressing the lack of access to clean drinking water in Africa.
ContributorsBarbur, Denisa Teodora (Author) / Gaughan, Monica (Thesis director) / Hruschka, Daniel (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2014-05
Description
A previous study demonstrated that learning to lift an object is context-based and that in the presence of both the memory and visual cues, the acquired sensorimotor memory to manipulate an object in one context interferes with the performance of the same task in presence of visual information about a different context (Fu et al, 2012).
The purpose of this study is to know whether the primary motor cortex (M1) plays a role in the sensorimotor memory. It was hypothesized that temporary disruption of the M1 following the learning to minimize a tilt using a ‘L’ shaped object would negatively affect the retention of sensorimotor memory and thus reduce interference between the memory acquired in one context and the visual cues to perform the same task in a different context.
Significant findings were shown in blocks 1, 2, and 4. In block 3, subjects displayed insignificant amount of learning. However, it cannot be concluded that there is full interference in block 3. Therefore, looked into 3 effects in statistical analysis: the main effects of the blocks, the main effects of the trials, and the effects of the blocks and trials combined. From the block effects, there is a p-value of 0.001, and from the trial effects, the p-value is less than 0.001. Both of these effects indicate that there is learning occurring. However, when looking at the blocks * trials effects, we see a p-value of 0.002 < 0.05 indicating significant interaction between sensorimotor memories. Based on the results that were found, there is a presence of interference in all the blocks but not enough to justify the use of TMS in order to reduce interference because there is a partial reduction of interference from the control experiment. It is evident that the time delay might be the issue between context switches. By reducing the time delay between block 2 and 3 from 10 minutes to 5 minutes, I will hope to see significant learning to occur from the first trial to the second trial.
The purpose of this study is to know whether the primary motor cortex (M1) plays a role in the sensorimotor memory. It was hypothesized that temporary disruption of the M1 following the learning to minimize a tilt using a ‘L’ shaped object would negatively affect the retention of sensorimotor memory and thus reduce interference between the memory acquired in one context and the visual cues to perform the same task in a different context.
Significant findings were shown in blocks 1, 2, and 4. In block 3, subjects displayed insignificant amount of learning. However, it cannot be concluded that there is full interference in block 3. Therefore, looked into 3 effects in statistical analysis: the main effects of the blocks, the main effects of the trials, and the effects of the blocks and trials combined. From the block effects, there is a p-value of 0.001, and from the trial effects, the p-value is less than 0.001. Both of these effects indicate that there is learning occurring. However, when looking at the blocks * trials effects, we see a p-value of 0.002 < 0.05 indicating significant interaction between sensorimotor memories. Based on the results that were found, there is a presence of interference in all the blocks but not enough to justify the use of TMS in order to reduce interference because there is a partial reduction of interference from the control experiment. It is evident that the time delay might be the issue between context switches. By reducing the time delay between block 2 and 3 from 10 minutes to 5 minutes, I will hope to see significant learning to occur from the first trial to the second trial.
ContributorsHasan, Salman Bashir (Author) / Santello, Marco (Thesis director) / Kleim, Jeffrey (Committee member) / Helms Tillery, Stephen (Committee member) / Barrett, The Honors College (Contributor) / W. P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
The purpose of this research was to analyze the EPODE Model for the development community-based interventions against childhood obesity and its transferability on a global scale. The Ensemble, Prevenons L'Obesite des Enfant (EPODE: Together Let's Prevent Childhood Obesity) Model was developed in France following the successful results of a community-based intervention there. The Model is illustrated by four pillars that are essential to program implementation and positive results. These pillars are: political support, research & evaluation, social marketing principles and public/private partnerships. Using these four pillars, the model has been transferred to diverse countries around the globe and has shown results in these diverse locations. In order to understand what makes this model so transferrable to so many diverse locations, this researcher traveled to the Netherlands, Belgium and France visiting program locations and interviewing professionals who have been involved in the development of the model, its modification and implementation. These interviews addressed specific modifications to the model that were made for implementation in the Netherlands and Belgium. This paper outlines the key transferrable components of this model and outlines a proposed model to be used in the United States.
ContributorsNielsen, Abigail Fanchon (Author) / Ohri-Vachaspati, Punam (Thesis director) / Barroso, Cristina (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Nutrition and Health Promotion (Contributor)
Created2014-05
Description
The purpose of this study was to investigate how the human-animal relationship affects one's willingness to seek veterinary care for a pet. It is important to understand this topic because past research has shown that companion animals play a very large role in the lives of many people. However, there has been a decline in the frequency of veterinary visits despite an increase in the number of pets. The variables of the human-animal relationship that were tested were one's views on the intelligence of a pet and its ability to feel emotions, and the closeness one feels to a pet. Demographic factors were also considered. The dependent variable of one's willingness to seek veterinary care was measured by the amount one would spend on veterinary treatment for a healthy pet, the amount one would spend on an older pet, and the responsibility one feels for the health and well-being of one's pet. The study revealed that the closeness one feels to a pet and one's views on a pet's ability to feel emotion both have a positive correlation with one's willingness to seek veterinary care for a pet. However, there was no correlation between one's views on the intelligence of a pet and one's willingness to seek veterinary care, and there was only a very slight correlation between income and one's willingness to seek veterinary care. Understanding these factors could be important in ensuring that companion animals receive the necessary care to promote their health and well-being.
ContributorsMagnussen, Hailey Eve (Author) / Hruschka, Daniel (Thesis director) / Risley-Curtiss, Christina (Committee member) / Barrett, The Honors College (Contributor) / T. Denny Sanford School of Social and Family Dynamics (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Curanderos are Hispanic traditional healers who attend to their clients through spiritual, natural, and physical techniques. Recent studies have shown that a subset of the Hispanic population refer to these healers for HIV and STD treatment and believe they are important in a collaborative targeted HIV intervention. Thus, curanderos were interviewed and the lay population of Phoenix was sampled in order to get a better idea of the utility of these healers in an HIV prevention effort targeted at the Hispanic community. Due to the limitations of this study there was not sufficient enough data to make significant conclusions; however the interviews with the curanderos were surprising in the they had significant roles as healers in the Phoenix area, patients have referred to them for HIV and STD treatment, and a couple of the healers have integrated western medical knowledge into their practice.
ContributorsMartinez, Justin Anthony (Author) / Maupin, Jonathan (Thesis director) / Hruschka, Daniel (Committee member) / Aguilera, Miguel (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
Electromyography (EMG) and Electroencephalography (EEG) are techniques used to detect electrical activity produced by the human body. EMG detects electrical activity in the skeletal muscles, while EEG detects electrical activity from the scalp. The purpose of this study is to capture different types of EMG and EEG signals and to determine if the signals can be distinguished between each other and processed into output signals to trigger events in prosthetics. Results from the study suggest that the PSD estimates can be used to compare signals that have significant differences such as the wrist, scalp, and fingers, but it cannot fully distinguish between signals that are closely related, such as two different fingers. The signals that were identified were able to be translated into the physical output simulated on the Arduino circuit.
ContributorsJanis, William Edward (Author) / LaBelle, Jeffrey (Thesis director) / Santello, Marco (Committee member) / Barrett, The Honors College (Contributor) / Computer Science and Engineering Program (Contributor)
Created2013-12
Description
Environmental and genetic factors contribute to schizophrenia etiology, yet few studies have demonstrated how environmental stimuli impact genes associated with the disorder. Immediate early genes (IEGs) are of great interest to schizophrenia research because they are activated in response to physiological stress from the environment, and subsequently regulate the expression of downstream genes that are essential to neuropsychiatric function. An IEG, early growth response 3 (EGR3) has been identified as a main gene involved in a network of transcription factors implicated in schizophrenia susceptibility. The serotonin 2A receptor (5-HT2AR) seems to play an important role in schizophrenia and the dysfunction of the 5-HT2AR encoding gene, HTR2A, within the prefrontal cortex (PFC) contributes to multiple psychiatric illnesses including schizophrenia. EGR3's role as a transcription factor that is activated by environmental stimuli suggests it may regulate Htr2a transcription in response to physiological stress, thus affecting 5-HT2AR function in the prefrontal cortex (PFC). The aim of this study was to examine the relationship between Egr3 activation and Htr2a expression after an environmental stimulus. Sleep deprivation is an acute physiological stressor that activates Egr3. Therefore to examine the relationship between Egr3 and Htr2a expression after an acute stress, wild type and Egr3 knockout mice that express EGFP under the control of the Htr2a promoter were sleep deprived for 8 hours. We used immunohistochemistry to determine the location and density of Htr2a-EGFP expression after sleep deprivation and found that Htr2a-EGFP expression was not affected by sex or subregions of the PFC. Additionally, Htr2a-EGFP expression was not affected by the loss of Egr3 or sleep deprivation within the PFC. The LPFC subregions, layers V and VI showed significantly more Htr2a-EGFP expression than layers I-III in all animals for both sleep deprivation and control conditions. Possible explanations for the lack of significant effects in this study may be the limited sample size or possible biological abnormalities in the Htr2a-EGFP mice. Nonetheless, we did successfully visualize the anatomical distribution of Htr2a in the prefrontal cortex via immunohistochemical staining. This study and future studies will provide insight into how Egr3 activation affects Htr2a expression in the PFC and how physiological stress from the environment can alter candidate schizophrenia gene function.
ContributorsSabatino, Alissa Marie (Author) / Gallitano, Amelia (Thesis director) / Hruschka, Daniel (Thesis director) / Maple, Amanda (Committee member) / Barrett, The Honors College (Contributor)
Created2014-05