Matching Items (130)
Description
Climate change presents the urgent need for effective sustainable water management that is capable of preserving natural resources while maintaining economical stability. States like California rely heavily on groundwater pumping for agricultural use, contributing to land subsidence and insufficient returns to water resources. The recent California drought has impacted agricultural production of certain crops. In this thesis, we present an agent-based model of farmers adapting to drought conditions by making crop choice decisions, much like the decisions Californian farmers have made. We use the Netlogo platform to capture the 2D spatial view of an agricultural system with changes in annual rainfall due to drought conditions. The goal of this model is to understand some of the simple rules farmers may follow to self-govern their consumption of a water resource. Farmer agents make their crop decisions based on deficit irrigation crop production function and a net present value discount rate. The farmers choose between a thirsty crop with a high production cost and a dry crop with a low production cost. Simulations results show that farmers switch crops in accordance with limited water and land resources. Farmers can maintain profit and yield by following simple rules of crop switching based on future yields and optimal irrigation. In drought conditions, individual agents expecting lower annual rainfall were able to increase their total profits. The maintenance of crop yield and profit is evidence of successful adaptation when farmers switch to crops that require less water.
ContributorsGokool, Rachael Shanta (Author) / Janssen, Marco (Thesis director) / Eakin, Hallie (Committee member) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
A major challenge with tissue samples used for biopsies is the inability to monitor their molecular quality before diagnostic testing. When tissue is resected from a patient, the cells are removed from their blood supply and normal temperature-controlled environment, which causes significant biological stress. As a result, the molecular composition and integrity undergo significant change. Currently, there is no method to track the effects of these artefactual stresses on the sample tissue to determine any deviations from the actual patient physiology. Without a way to track these changes, pathologists have to blindly trust that the tissue samples they are given are of high quality and fit for molecular analysis; physicians use the analysis to make diagnoses and treatment plans based on the assumption that the samples are valid. A possible way to track the quality of the tissue is by measuring volatile organic compounds (VOCs) released from the samples. VOCs are carbon-based chemicals with high vapor pressure at room temperature. There are over 1,800 known VOCs within humans and a number of these exist in every tissue sample. They are individualized and often indicative of a person’s metabolic condition. For this reason, VOCs are often used for diagnostic purposes. Their usefulness in diagnostics, reflectiveness of a person’s metabolic state, and accessibility lends them to being beneficial for tracking degradation. We hypothesize that there is a relationship between the change in concentration of the volatile organic compounds of a sample, and the molecular quality of a sample. This relationship is what would indicate the accuracy of the tissue quality used for a biopsy in relation to the tissue within the body.
ContributorsSharma, Nandini (Co-author) / Fragoso, Claudia (Co-author) / Grenier, Tyler (Co-author) / Hanson, Abigail (Co-author) / Compton, Carolyn (Thesis director) / Tao, Nongjian (Committee member) / Moakley, George (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Coffee is an important link between the United States and Latin America and an important part of Latin America’s culture and economy. This paper looks at the similarities and differences between coffee organizations in Colombia, Ecuador, Peru, and Guatemala. Colombia has the strongest coffee organizations with the most political power. Guatemala and Peru, to a lesser extent, have well organized and powerful organizations that make up their industry. However, Ecuador has a significantly less organized organization. At their core, each country has a similar structure. There is one organization on the national level that watches out for the industry as a whole. Underneath that, there are smaller, often regional organizations made up of cooperatives pooling their resources for export. They function in similar ways as the national organizations, but have less reach. At the bottom, there are individual cooperatives and independent farmers. These cooperatives do not have much reach or connection to international markets.
ContributorsChabin, James Edward (Author) / Janssen, Marco (Thesis director) / Taylor, Keith (Committee member) / School of Sustainability (Contributor) / School of International Letters and Cultures (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Polymer modified tuning fork-based sensors were fabricated to assure reproducibility. The effect of system valve switching on the modified tuning fork-based sensors was studied at the different temperature. The response to Xylene gas sample on stabilized modified tuning fork-based sensors with temperature was defined while learning about the key analytical performance for chemical sensors to be used in the real-world application.
ContributorsRohit, Riddhi S (Author) / Forzani, Erica (Thesis director) / Tsow, Francis (Committee member) / Dean, W.P. Carey School of Business (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
It is well established that physical activity (PA) directly correlates with many health benefits, especially when active habits are formed during childhood and adolescence. PA practiced in adolescence has been seen to carry into adulthood, helping to combat a host of chronic diseases, such as obesity and diabetes. However, in recent years there has been a steady decline in PA among adolescents, followed by a resulting rise in sedentary behavior. Walking Intervention Through Texting for Adolescents, or WalkIT-A, was an 11.5-week intervention that built upon behavioral theory to provide an incentive-based, adaptive, physical activity intervention to inactive adolescents. The goal of this study was to investigate an intervention which combined walking with pointed behavior change strategies to incite a larger increase in PA. Using single-case, reversal (ABA) design, the study was aimed at shaping physical activity behavior in adolescents aged 12-17 through a mobile health intervention that paired adaptive goal setting with financial incentives to increase step count. The intervention was delivered using a semi-automated texting, mobile-Health (mHealth) platform, which incorporated FitBit tracking technology, adaptive goals, motivational messages, performance feedback, and points/incentives. It was hypothesized that during the adaptive intervention phase participants would increase both steps per day and active minutes compared to baseline values. Upon conclusion of the study, the three adolescent participants exhibited increased steps and active minutes during the intervention period compared to baseline and withdrawal phases. However, the specific trends identified suggest the need for future research to incorporate even stronger intervention components to overcome PA "drop-off" midway through the intervention, along with other external, environmental influencers. Despite this need, the use of adaptive goal setting combined with incentives can be an effective means to incite PA behavior change in adolescents.
ContributorsVan Bussum, Courtney Jessica (Author) / Adams, Marc (Thesis director) / Forzani, Erica (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor) / School of Nutrition and Health Promotion (Contributor)
Created2016-12
Description
Membrane based technology is one of the principal methods currently in widespread use to address the global water shortage. Pervaporation desalination is a membrane technology for water purification currently under investigation as a method for processing reverse osmosis concentrates or for stand-alone applications. Concentration polarization is a potential problem in any membrane separation. In desalination concentration polarization can lead to reduced water flux, increased propensity for membrane scaling, and decreased quality of the product water. Quantifying concentration polarization is important because reducing concentration polarization requires increased capital and operating costs in the form of feed spacers and high feed flow velocities. The prevalent methods for quantifying concentration polarization are based on the steady state thin film boundary layer theory. Baker’s method, previously used for pervaporation volatile organic compound separations but not desalination, was successfully applied to data from five previously published pervaporation desalination studies. Further investigation suggests that Baker’s method may not have wide applicability in desalination. Instead, the limitations of the steady state assumption were exposed. Additionally, preliminary results of nanophotonic enhancement of pervaporation membranes were found to produce significant flux enhancement. A novel theory on the mitigation of concentration polarization by the photothermal effect was discussed.
ContributorsMann, Stewart, Ph.D (Author) / Lind, Mary Laura (Thesis advisor) / Walker, Shane (Committee member) / Green, Matthew (Committee member) / Forzani, Erica (Committee member) / Emady, Heather (Committee member) / Arizona State University (Publisher)
Created2019
Description
This study examined perception of K12 schooling systems as experienced by a randomsample of adults in Phoenix, AZ. It explored whether the values purported as key factors
in the American K12 schooling system - as presented in academic literature - were compatible with the lives, interests and goals of ‘users’, student-participants. In addition, it offered opportunity for post-K12 student-participants to share their views on the purposes, goals, and outcomes they held to be important. The sample consisted of 139 post-K12 stu-
dents/individuals residing in Phoenix, AZ. Mean age of student-participants was 29. Results indicated a mismatch between purported K12 schooling goals and important outcomes embedded in the system and values held by the K12 student-participants. The participants in this research generally perceived K12 schooling as valuable, both to themselves and to society at large, but stressed that the deficiencies they perceived in the system were particular to delivery platforms as they relate to the learning styles of students and belonging. Future life skills and success - in and after K12 schooling - whether related to college or not were also of importance. Results revealed that the initial hypothesis of income, age, and ethnicity as
key factors in satisfaction with K12 schooling was not borne-out. Rather it revealed that a sense of belonging and the suitability of learning platforms to the individual learning styles of students were of greatest significance.
ContributorsParker-Anderies, Margaret (Author) / Janssen, Marco (Thesis advisor) / Garcia, David (Committee member) / Mishra, Punya (Committee member) / Arizona State University (Publisher)
Created2022
Description
Obesity has consistently presented a significant challenge, with excess body fat contributing to the development of numerous severe conditions such as diabetes, cardiovascular disease, cancer, and various musculoskeletal disorders. In this study, different methods are proposed to study substrate utilization (carbohydrates, proteins, and fats) in the human body and validate the biomarkers enabling to investigation of weight management and monitor metabolic health. The first technique to study was Indirect calorimetry, which assessed Resting Energy Expenditure (REE) and measured parameters like oxygen consumption (VO2) and carbon dioxide production (VCO2). A validation study was conducted to study the effectiveness of the medical device Breezing Med determining REE, VO2, and VCO2. The results were compared with correlation slopes and regression coefficients close to 1. Indirect Calorimetry can be used to determine carbohydrate and fat utilization but it requires additional correction for protein utilization. Protein utilization can be studied by analyzing urinary nitrogen. Therefore, a secondary technique was studied for identifying urea and ammonia concentration in human urine samples. Along this line two methods for detecting urea were explored, a colorimetric technique and it was validated against the Ion-Selective method. The results were then compared by correlation analysis of urine samples measured with both methods simultaneously curves. The equations for fat, carb, and protein oxidation, involving VO2, VCO2 consumption, and urinary nitrogen were implemented and validated, using the above-described methods in a human subject study with 16 subjects. The measurements included diverse diets (normal vs. high fat/protein) in normal energy balance and pre-/post interventions of exercise, fasting, and a high-fat meal. It can be concluded that the indirect calorimetry portable method in conjunction with urine urea methods are important to help the understanding of substrate utilization in human subjects, and therefore, excellent tools to contribute to the treatments and interventions of obesity and overweighted populations.
ContributorsPradhan, Ayushi (Author) / Forzani, Erica (Thesis advisor) / Lind, Mary Laura (Committee member) / Wang, Shaopeng (Committee member) / Arizona State University (Publisher)
Created2023
Description
Cardiovascular disease is affecting millions of people worldwide and is the leading cause of death in the United States. This disease is closely related to the abnormal creatinine levels in blood. For this reason, there is a need for a low-cost point-of-care device that could measure the creatinine level in blood with the goal of managing and preventing cardiovascular disease. This project introduces a Molecular Reactive Lateral Flow Assay (MoReLFA) device that is aimed toward creatinine detection based on an optimized chemical reaction of creatinine and alkaline picrate. The device consists of different membranes that accommodate 50 microliters of fluid sample and carry out a colorimetric reaction, in which deposited-colored region is analyzed for Red, Green, and Blue (RGB) components via an image processing software. The color intensity from the RGB outputs was then studied and compared with a gold standard spectrophotometry-based technique. The results show that the MoReLFA sensor could successfully detect creatinine levels in standard solutions. The plot of the sensor color intensity against the absorbance from spectrophotometry shows a good correlation between the two methods (R2 = 0.96). Furthermore, the paper introduces the development of a RGB reader box that is portable and for easy assessment of RGB values. The color intensity from the box shows an increasing trend with increasing creatinine concentrations; and the coefficient of determination of this relationship is 0.85.
ContributorsNguyen, Ngan Anh (Author) / Raupp, Gregory (Thesis advisor) / Forzani, Erica (Thesis advisor) / Mora, Sabrina Jimena (Committee member) / Arizona State University (Publisher)
Created2022
Description
The consumption of food, energy, and water (FEW) resources in U.S. households is very carbon-intensive. However, these negative climate change impacts are often invisible due to insufficient awareness and knowledge. Serious games (SGs) can potentially address this issue through an experiential and rigorous approach to simulate household actions and impacts in a playful but realistic setting. This dissertation focuses on: (a) the design and testing of an SG called HomeRUN (Role-play for Understanding Nexus); (b) the effectiveness of gameplay in advancing player knowledge about the upfront costs, financial returns, and greenhouse gas (GHG) emissions of various household decisions; and (c) the effectiveness of intervention messages in increasing FEW conservation to reduce household GHG emissions. The results of gameplay sessions played by 150 university students show that HomeRUN is fun to play, creates a flow experience, and results in experiential learning. The majority of players agreed that the game experience will continue over time to influence their future consumption behaviors to conserve FEW resources. Female players tended to gain more knowledge about financial aspects of interventions, whereas male players were more likely to increase their understandings of GHG emissions and resource consumption after playing HomeRUN. Social comparison intervention messages about energy and food consumption led to the highest reductions in household carbon emissions. The messages associated with each FEW resource tended to be most likely to lead to FEW conservation actions with the game that most closely corresponded to the particular FEW resource addressed in the message. This dissertation advances understandings about the design and use of SGs to foster learning and promote sustainable household FEW consumption.
ContributorsHanif, Muhammad Adnan (Author) / Agusdinata, Datu Buyung (Thesis advisor) / Halvorsen, Kathleen (Committee member) / Janssen, Marco (Committee member) / Arizona State University (Publisher)
Created2021