Matching Items (146)
Description
Evolving Earth observation and change detection techniques enable the automatic identification of Land Use and Land Cover Change (LULCC) over a large extent from massive amounts of remote sensing data. It at the same time poses a major challenge in effective organization, representation and modeling of such information. This study proposes and implements an integrated computational framework to support the modeling, semantic and spatial reasoning of change information with regard to space, time and topology. We first proposed a conceptual model to formally represent the spatiotemporal variation of change data, which is essential knowledge to support various environmental and social studies, such as deforestation and urbanization studies. Then, a spatial ontology was created to encode these semantic spatiotemporal data in a machine-understandable format. Based on the knowledge defined in the ontology and related reasoning rules, a semantic platform was developed to support the semantic query and change trajectory reasoning of areas with LULCC. This semantic platform is innovative, as it integrates semantic and spatial reasoning into a coherent computational and operational software framework to support automated semantic analysis of time series data that can go beyond LULC datasets. In addition, this system scales well as the amount of data increases, validated by a number of experimental results. This work contributes significantly to both the geospatial Semantic Web and GIScience communities in terms of the establishment of the (web-based) semantic platform for collaborative question answering and decision-making.
ContributorsVadjunec, Jacqueline M. (Author) / Radel, Claudia (Author) / Turner II, B. L. (Author) / College of Liberal Arts and Sciences (Contributor) / School of Geographical Sciences and Urban Planning (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor) / School of Sustainability (Contributor)
Created2016-10-25
Description
The growth rate hypothesis (GRH) proposes that higher growth rate (the rate of change in biomass per unit biomass, μ) is associated with higher P concentration and lower C∶P and N∶P ratios. However, the applicability of the GRH to vascular plants is not well-studied and few studies have been done on belowground biomass. Here we showed that, for aboveground, belowground and total biomass of three study species, μ was positively correlated with N∶C under N limitation and positively correlated with P∶C under P limitation. However, the N∶P ratio was a unimodal function of μ, increasing for small values of μ, reaching a maximum, and then decreasing. The range of variations in μ was positively correlated with variation in C∶N∶P stoichiometry. Furthermore, μ and C∶N∶P ranges for aboveground biomass were negatively correlated with those for belowground. Our results confirm the well-known association of growth rate with tissue concentration of the limiting nutrient and provide empirical support for recent theoretical formulations.
ContributorsYu, Qiang (Author) / Wu, Honghui (Author) / He, Nianpeng (Author) / Lu, Xiaotao (Author) / Wang, Zhiping (Author) / Elser, James (Author) / Wu, Jianguo (Author) / Han, Xingguo (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor) / School of Sustainability (Contributor)
Created2012-03-13
Grasshoppers Regulate N: P Stoichiometric Homeostasis by Changing Phosphorus Contents in Their Frass
Description
Nitrogen (N) and phosphorus (P) are important limiting nutrients for plant production and consumer performance in a variety of ecosystems. As a result, the N:P stoichiometry of herbivores has received increased attention in ecology. However, the mechanisms by which herbivores maintain N:P stoichiometric homeostasis are poorly understood. Here, using a field manipulation experiment we show that the grasshopper Oedaleus asiaticus maintains strong N:P stoichiometric homeostasis regardless of whether grasshoppers were reared at low or high density. Grasshoppers maintained homeostasis by increasing P excretion when eating plants with higher P contents. However, while grasshoppers also maintained constant body N contents, we found no changes in N excretion in response to changing plant N content over the range measured. These results suggest that O. asiaticus maintains P homeostasis primarily by changing P absorption and excretion rates, but that other mechanisms may be more important for regulating N homeostasis. Our findings improve our understanding of consumer-driven P recycling and may help in understanding the factors affecting plant-herbivore interactions and ecosystem processes in grasslands.
ContributorsZhang, Zijia (Author) / Elser, James (Author) / Cease, Arianne (Author) / Zhang, Ximei (Author) / Yu, Qiang (Author) / Han, Xingguo (Author) / Zhang, Guangming (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor) / School of Sustainability (Contributor)
Created2014-08-04
Description
When viewing vitamins and minerals, it is seen that they are essential for human life and vital for pregnancy. When paired with a healthy diet, prenatal supplements can allow for a healthy pregnancy and reduced maternal and infant health problems. Within this thesis, I was able to break down each vitamin and mineral necessary for a healthy pregnancy and birth. Further, I had the opportunity to dive into the addition of Omega-3 Fatty Acid during pregnancy to add more evidence to the study.
ContributorsSaad, Sophia Saad (Author) / Adams, James (Thesis director) / Haiwei, Gu (Committee member) / Coleman, Devon (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
A large fraction of the world grasslands and savannas are undergoing a rapid shift from herbaceous to woody-plant dominance. This land-cover change is expected to lead to a loss in livestock production (LP), but the impacts of woody-plant encroachment on this crucial ecosystem service have not been assessed. We evaluate how tree cover (TC) has affected LP at large spatial scales in rangelands of contrasting social–economic characteristics in the United States and Argentina. Our models indicate that in areas of high productivity, a 1% increase in TC results in a reduction in LP ranging from 0.6 to 1.6 reproductive cows (Rc) per km[superscript 2]. Mean LP in the United States is 27 Rc per km[superscript 2], so a 1% increase in TC results in a 2.5% decrease in mean LP. This effect is large considering that woody-plant cover has been described as increasing at 0.5% to 2% per y. On the contrary, in areas of low productivity, increased TC had a positive effect on LP. Our results also show that ecological factors account for a larger fraction of LP variability in Argentinean than in US rangelands. Differences in the relative importance of ecological versus nonecological drivers of LP in Argentina and the United States suggest that the valuation of ecosystem services between these two rangelands might be different. Current management strategies in Argentina are likely designed to maximize LP for various reasons we are unable to explore in this effort, whereas land managers in the United States may be optimizing multiple ecosystem services, including conservation or recreation, alongside LP.
ContributorsAnadon, Jose Daniel (Author) / Sala, Osvaldo (Author) / Turner II, B. L. (Author) / Bennett, Elena M. (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor) / School of Sustainability (Contributor) / School of Geographical Sciences and Urban Planning (Contributor)
Created2014-09-02
Description
We studied the microbial community structure of pilot two-stage membrane biofilm reactors (MBfRs) designed to reduce nitrate (NO[subscript 3]–) and perchlorate (ClO[subscript 4]–) in contaminated groundwater. The groundwater also contained oxygen (O[subscript 2]) and sulfate (SO[2 over 4]–), which became important electron sinks that affected the NO[subscript 3]– and ClO[subscript 4]– removal rates. Using pyrosequencing, we elucidated how important phylotypes of each “primary” microbial group, i.e., denitrifying bacteria (DB), perchlorate-reducing bacteria (PRB), and sulfate-reducing bacteria (SRB), responded to changes in electron-acceptor loading. UniFrac, principal coordinate analysis (PCoA), and diversity analyses documented that the microbial community of biofilms sampled when the MBfRs had a high acceptor loading were phylogenetically distant from and less diverse than the microbial community of biofilm samples with lower acceptor loadings. Diminished acceptor loading led to SO[2 over 4]– reduction in the lag MBfR, which allowed Desulfovibrionales (an SRB) and Thiothrichales (sulfur-oxidizers) to thrive through S cycling. As a result of this cooperative relationship, they competed effectively with DB/PRB phylotypes such as Xanthomonadales and Rhodobacterales. Thus, pyrosequencing illustrated that while DB, PRB, and SRB responded predictably to changes in acceptor loading, a decrease in total acceptor loading led to important shifts within the “primary” groups, the onset of other members (e.g., Thiothrichales), and overall greater diversity.
ContributorsOntiveros-Valencia, Aura (Author) / Tang, Youneng (Author) / Zhao, Heping (Author) / Friese, David (Author) / Overstreet, Ryan (Author) / Smith, Jennifer (Author) / Evans, Patrick (Author) / Rittmann, Bruce (Author) / Krajmalnik-Brown, Rosa (Author) / Biodesign Institute (Contributor) / Swette Center for Environmental Biotechnology (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor) / School of Sustainability (Contributor)
Created2014-07-01
Description
Introduction: The Eye to Eye mentorship program is a national program in which college or high school students with learning differences mentor middle school students with learning differences. There are 68 Eye to Eye programs around the country, but little research has been done on their effectiveness and how to improve it. We conducted and evaluated one program site at Arizona State University and implemented this mentorship program for the first time during 2019. We hypothesized the Eye to Eye mentorship program that paired college students who have learning differences with middle school students who have similar learning differences would improve the outcomes and socio-behavior skills of both mentors and mentees.
Methods: The Eye to Eye mentorship program assessed involved mentors and mentees who completed 12 in-person art sessions out of the normal 20 in-person sessions. The first main assessment was the BLD (Breger Learning Difference) Feedback Survey addressing one’s experience in the Eye to Eye program and which were completed at the end of the mentorship program and filled out by mentors, mentees, and mentees parents (one parent for each mentee). A total of 12 mentors, 6 mentees, and 6 mentee parents were included in the feedback survey final analysis. The second main assessments were the pre and post Behavior Assessment System for Child, Third Edition (BASC-3) provided to mentors, mentees, and mentees parents (one parent for each mentee). A total of 10 mentors, 5 mentees, and 5 mentee parents were included in pre and post BASC-3 final analysis. Fall 2019 (pre) and Spring 2020 (post) optional interviews involved 5 mentors and 3 mentees who showed interest and were comfortable participating with additional release forms.
Results: The program was generally positively rated in the feedback survey by mentors, mentees, and mentee parents. The highest responses for mentors, mentees, and mentee parents all incorporated average ratings of 4.0 or higher (out of 5.0) for perceived understanding of socio-emotional skills after Eye to Eye, experience in Eye to Eye, how having a mentor or mentee made them feel, and perceived change in self-awareness. All three groups reported fairly high ratings of improved self-awareness of 4.0/5.0 or above. No negative ratings were provided by any participants and the lowest response was no change. The BASC-3 evaluation found statistically significant improvement in mentors’ anxiety and atypicality and mentees’ sense of inadequacy.
Discussion: The Eye to Eye program was popular and well-rated despite only involving 12 in- person one-hour art sessions. The mentors, mentees, and mentee parents felt positive about the Eye to Eye program when answering the feedback survey. Some suggestions are made on how to improve this program to better enhance someone with learning differences future ability to succeed. Future research is needed to assess the true impact due to the COVID-19 epidemic and other limitations.
Methods: The Eye to Eye mentorship program assessed involved mentors and mentees who completed 12 in-person art sessions out of the normal 20 in-person sessions. The first main assessment was the BLD (Breger Learning Difference) Feedback Survey addressing one’s experience in the Eye to Eye program and which were completed at the end of the mentorship program and filled out by mentors, mentees, and mentees parents (one parent for each mentee). A total of 12 mentors, 6 mentees, and 6 mentee parents were included in the feedback survey final analysis. The second main assessments were the pre and post Behavior Assessment System for Child, Third Edition (BASC-3) provided to mentors, mentees, and mentees parents (one parent for each mentee). A total of 10 mentors, 5 mentees, and 5 mentee parents were included in pre and post BASC-3 final analysis. Fall 2019 (pre) and Spring 2020 (post) optional interviews involved 5 mentors and 3 mentees who showed interest and were comfortable participating with additional release forms.
Results: The program was generally positively rated in the feedback survey by mentors, mentees, and mentee parents. The highest responses for mentors, mentees, and mentee parents all incorporated average ratings of 4.0 or higher (out of 5.0) for perceived understanding of socio-emotional skills after Eye to Eye, experience in Eye to Eye, how having a mentor or mentee made them feel, and perceived change in self-awareness. All three groups reported fairly high ratings of improved self-awareness of 4.0/5.0 or above. No negative ratings were provided by any participants and the lowest response was no change. The BASC-3 evaluation found statistically significant improvement in mentors’ anxiety and atypicality and mentees’ sense of inadequacy.
Discussion: The Eye to Eye program was popular and well-rated despite only involving 12 in- person one-hour art sessions. The mentors, mentees, and mentee parents felt positive about the Eye to Eye program when answering the feedback survey. Some suggestions are made on how to improve this program to better enhance someone with learning differences future ability to succeed. Future research is needed to assess the true impact due to the COVID-19 epidemic and other limitations.
ContributorsBreger, Chloe Levana (Author) / Adams, James (Thesis director) / Harris, Pamela (Committee member) / School of Criminology and Criminal Justice (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Graphene has the ability to advance many common fields, including: membranes, composites and coatings, energy, and electronics. For membranes, graphene will be used as a filter for desalination plants which will reduce the cost of desalination and greatly increase water security in developing countries. For composites and coatings, graphene's strength, flexibility, and lightweight will be instrumental in producing the next generation of athletic wear and sports equipment. Graphene's use in energy comes from its theorized ability to charge a phone battery in seconds or an electric car in minutes. Finally, for electronics, graphene will be used to create faster transistors, flexible electronics, and fully integrated wearable technology.
ContributorsSiegel, Adam (Author) / Adams, James (Thesis director) / Krause, Stephen (Committee member) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This is a two-part thesis, completed in conjunction with my Materials Science and Engineering Capstone Project. The first part involves the design and testing of cold-extruded high-density polyethylene for student oboe reeds. The goal of this section was to create a longer-lasting reed that produces a similar sound to a cane reed, has less variation in quality, and costs less per year than cane reeds. For low-income students in particular, the cost of purchasing cane oboe reeds ($500-$2,000 per year) is simply not feasible. This project was designed to allow oboe to be a more affordable option for all students. Money should not be a factor that limits whether or a not a child is able to explore their interests. The process used to create the synthetic reed prototype involves cold-extrusion of high-density polyethylene in order to induce orientation in the polymer to replicate the uniaxial orientation of fibrous cane. After successful cold-extrusion of a high-density polyethylene (HDPE) cylinder, the sample was made into a reed by following standard reedmaking procedures. Then, the HDPE reed and a cane reed were quantitatively tested for various qualities, including flexural modulus, hardness, and free vibration frequency. The results from the design project are promising and show a successful proof of concept. The first prototype of an oriented HDPE reed demonstrates characteristics of a cane reed. The areas that need the most improvement are the flexural modulus and the stability of the higher overtones, but these areas can be improved with further development of the cold-extrusion process. The second part of this thesis is a survey and analysis focusing on the qualitative comparison of synthetic and cane oboe reeds. The study can be used in the future to refine the design of synthetic reeds, more specifically the cold-extruded high-density polyethylene student oboe reed I designed, to best replicate a cane reed. Rather than approaching this study from a purely engineering mindset, I brought in my own experience as an oboist. Therefore, the opinions of oboists who have a wide range of experience are considered in the survey. A panel of five oboists participated in the survey. They provided their opinion on various aspects of the five reeds, including vibrancy, response, stability, resistance, tone, and overall quality. Each of these metrics are rated on a scale from one to five, from unacceptable to performance quality. According to the survey, a participant's personal, hand-made cane reed is overall the most preferred option. My prototype HDPE student reed must be improved in many areas in order to rank near the other four reeds. However, its vibrancy and resistance already rival that of a Jones student reed. As this is just the first prototype, that is a significant accomplishment. With further refinement of the cold-extrusion and reedmaking method, the other areas of the HDPE reed may be improved, and the reed may eventually compete with the existing synthetic and cane reeds on the market.
ContributorsMitchell, Alexis Jacqueline (Author) / Adams, James (Thesis director) / Schuring, Martin (Committee member) / School of Music (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
The gastrointestinal (GI) tract is home to a complex and diverse microbial ecosystem that contributes to health or disease in many aspects. While bacterial species are the majority in the GI tract, their cohabitants, fungal species, should not be forgotten. Children with autism spectrum disorder (ASD) often suffer from GI disorders and associated symptoms, implying a role the bacterial and fungal gut microbiota play in maintaining human health. The irregularities in GI symptoms can negatively affect the overall quality of life or even worsen behavioral symptoms the children present. Even with the increase in the availability of next-generation sequencing technologies, the composition and diversities of fungal microbiotas are understudied, especially in the context of ASD. We therefore aimed to investigate the gut mycobiota of 36 neurotypical children and 38 children with ASD. We obtained stool samples from all participants, as well as autism severity and GI symptom scores to help us understand the effect the mycobiome has on these symptoms. By targeting the fungal internal transcribed spacer (ITS) and bacterial 16S rRNA V4 regions, we obtained fungal and bacterial amplicon sequences, from which we investigated the diversities, composition, and potential link between two different ecological clades. From fungal amplicon sequencing results, we observed a significant decrease in the observed fungal OTUs in children with ASD, implying a lack of potentially beneficial fungi in ASD subjects. We performed Bray-Curtis principal coordinates analysis and observed significant differences in fungal microbiota composition between the two groups. Taxonomic analysis showed higher relative abundances of Candida , Pichia, Penicillium , and Exophiala in ASD subjects, yet due to a large dispersion of data, the differences were not statistically significant. Interestingly, we observed a bimodal distribution of Candida abundances within children with ASD. Candida's relative abundance was not significantly correlated with GI scores, but children with high Candida relative abundances presented significantly higher Autism Treatment Evaluation Checklist (ATEC) scores, suggesting a role of Candida on ASD behavioral symptoms. Regarding the bacterial gut microbiota, we found marginally lower observed OTUs and significantly lower relative abundance of Prevotella in the ASD group, which was consistent with previous studies. Taken together, we demonstrated that autism is closely linked with a distinct gut mycobiota, characterized by a loss of fungal and bacterial diversity and an altered fungal and bacterial composition.
ContributorsPatel, Jigar (Author) / Krajmalnik-Brown, Rosa (Thesis director) / Kang, Dae Wook (Committee member) / Adams, James (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05