Matching Items (370)
Description
Nutrient recycling by fish can be an important part of nutrient cycles in both freshwater and marine ecosystems. As a result, understanding the mechanisms that influence excretion elemental ratios of fish is of great importance to a complete understanding of aquatic nutrient cycles. As fish consume a wide range of diets that differ in elemental composition, stoichiometric theory can inform predictions about dietary effects on excretion ratios.
We conducted a meta-analysis to test the effects of diet elemental composition on consumption and nutrient excretion by fish. We examined the relationship between consumption rate and diet N : P across all laboratory studies and calculated effect sizes for each excretion metric to test for significant effects.
Consumption rate of N, but not P, was significantly negatively affected by diet N : P. Effect sizes of diet elemental composition on consumption-specific excretion N, P and N : P in laboratory studies were all significantly different from 0, but effect size for raw excretion N : P was not significantly different from zero in laboratory or field surveys.
Our results highlight the importance of having a mechanistic understanding of the drivers of consumer excretion rates and ratios. We suggest that more research is needed on how consumption and assimilation efficiency vary with N : P and in natural ecosystems in order to further understand mechanistic processes in consumer-driven nutrient recycling.
ContributorsMoody, Eric (Author) / Corman, Jessica (Author) / Elser, James (Author) / Sabo, John (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor)
Created2015-03-01
Description
Preserving a system’s viability in the presence of diversity erosion is critical if the goal is to sustainably support biodiversity. Reduction in population heterogeneity, whether inter- or intraspecies, may increase population fragility, either decreasing its ability to adapt effectively to environmental changes or facilitating the survival and success of ordinarily rare phenotypes. The latter may result in over-representation of individuals who may participate in resource utilization patterns that can lead to over-exploitation, exhaustion, and, ultimately, collapse of both the resource and the population that depends on it. Here, we aim to identify regimes that can signal whether a consumer–resource system is capable of supporting viable degrees of heterogeneity. The framework used here is an expansion of a previously introduced consumer–resource type system of a population of individuals classified by their resource consumption. Application of the Reduction Theorem to the system enables us to evaluate the health of the system through tracking both the mean value of the parameter of resource (over)consumption, and the population variance, as both change over time. The article concludes with a discussion that highlights applicability of the proposed system to investigation of systems that are affected by particularly devastating overly adapted populations, namely cancerous cells. Potential intervention approaches for system management are discussed in the context of cancer therapies.
ContributorsKareva, Irina (Author) / Morin, Benjamin (Author) / Castillo-Chavez, Carlos (Author) / Simon M. Levin Mathematical, Computational and Modeling Sciences Center (Contributor) / College of Liberal Arts and Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor)
Created2015-02-01
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
This survey was used to identify the concerns of the public. There are many population techniques that the public feels are harmful to the behavior and nature of the horses. This research defined the different techniques and history of the situation to then analyze the public's opinion of the topic. The survey was trying to determine if any of the techniques could be accepted by the public to control the population of the horses that won’t put the forest, other species, and the herds themselves in danger of possible overpopulation effects.
The data collected from this research showed conflict for the subject. Some of the data was skewed due to conflicting viewpoints on the topic. Analyzing the other aspects of the data we saw noticed that 73% of the servers felt the horses were wild. A majority agreed that the horses should stay there and not be relocated. Some individuals who took the survey were interested in adopting out the horses to help manage horses, there were some concerns with background checks for these adopters since slaughter houses and poor living conditions is a concern.
The data collected from this research showed conflict for the subject. Some of the data was skewed due to conflicting viewpoints on the topic. Analyzing the other aspects of the data we saw noticed that 73% of the servers felt the horses were wild. A majority agreed that the horses should stay there and not be relocated. Some individuals who took the survey were interested in adopting out the horses to help manage horses, there were some concerns with background checks for these adopters since slaughter houses and poor living conditions is a concern.
ContributorsPadayachee, Brittany (Co-author) / Hoover, Sierra (Co-author) / Roen, Duane (Thesis director) / Murphree, Julie (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
This survey was used to identify the concerns of the public. There are many population techniques that the public feels are harmful to the behavior and nature of the horses. This research defined the different techniques and history of the situation to then analyze the public's opinion of the topic. The survey was trying to determine if any of the techniques could be accepted by the public to control the population of the horses that won’t put the forest, other species, and the herds themselves in danger of possible overpopulation effects.
The data collected from this research showed conflict for the subject. Some of the data was skewed due to conflicting viewpoints on the topic. Analyzing the other aspects of the data we saw noticed that 73% of the servers felt the horses were wild. A majority agreed that the horses should stay there and not be relocated. Some individuals who took the survey were interested in adopting out the horses to help manage horses, there were some concerns with background checks for these adopters since slaughter houses and poor living conditions is a concern.
The data collected from this research showed conflict for the subject. Some of the data was skewed due to conflicting viewpoints on the topic. Analyzing the other aspects of the data we saw noticed that 73% of the servers felt the horses were wild. A majority agreed that the horses should stay there and not be relocated. Some individuals who took the survey were interested in adopting out the horses to help manage horses, there were some concerns with background checks for these adopters since slaughter houses and poor living conditions is a concern.
ContributorsHoover, Sierra Nicole (Co-author) / Padayachee, Brittany (Co-author) / Roen, Duane (Thesis director) / Murphree, Julie (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
The purpose of this project was to create a workshop for adults without dance experience to immerse them in dance as a form of therapy. The goals of this workshop are to foster physical awareness and physical creativity. There are four main areas the participants would get experience in from this workshop including self-care/awareness, expression, gesture and choreography. These four areas are the ways that the two main goals manifest themselves. For this project I reviewed research by many different professionals from the therapy, psychology, self-care, dance, and dance therapy fields. Their studies as well as my own experience aided in putting together my themes for the workshop and class activities. I include my methodology, lesson plans, a workbook, and my reflection on the process.
ContributorsWilson, Deepika (Author) / Roses-Thema, Cynthia (Thesis director) / Giorgis, Cyndi (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
Particulate matter (PM) air pollution is a known factor to exacerbate cardiopulmonary diseases. We previously demonstrated that PM mediated endothelial injury and barrier disruption via modulation of the endothelial cytoskeleton and cell-cell junctions, while the effects of PM exposure on cell-cell communication and gap junction activity are still unknown. This study is focused on the characterization of PM-mediated endothelial dysfunction via Connexin 43 (Cx43), the most abundant Gap junction protein expressed in lung endothelial cells (ECs). PM exposure induces a time-dependent elevation of Cx43 in human lung ECs, at both mRNA and protein levels. N-acetyl-cysteine (NAC), an ROS scavenger, significantly suppresses PM-induced Cx43 expression. Membrane-associated and ER/ Golgi apparatus Cx43 protein are elevated upon PM challenge. In addition, PM also activates the gap junction activity, indicated by the transportation of green fluorescence dye between two adjacent ECs. Moreover, GAP27, a selective Cx43 channel inhibitor, attenuates PM-reduced human lung EC barrier disruption, measured by trans-endothelial electrical resistance (TER) with an electric cell-substrate impedance sensing system. Moreover, knock-down the expression of Cx43 by its selective siRNA alleviates PM-induced MLC phosphorylation. These results highly suggest that Cx43 plays a key role in PM-mediated endothelial barrier disruption and signal transduction. Cx43 may deputy as a therapeutic target in PM-mediated cardiopulmonary disorders.
ContributorsKheshtchin-Kamel, Nabia (Author) / Welcome, Natalie (Thesis director) / Wang, Ting (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12
Description
“Sam’s Emotional Day: A Child’s Guide to Recognizing and Handling Emotions” is a creative project that fulfills the thesis requirement for Barrett, The Honors College at Arizona State University. It is an illustrated children’s book meant to help children ages 4-7 identify, understand, and manage the six basic emotions. The illustrations of the main character throughout the book display clear facial expressions associated with each emotion, which were designed for children to easily identify them. The text in the story portion will prompt children to understand the feelings behind each emotion in a simple matter, and the end of the book provides techniques for them to manage emotions. Research on the importance of teaching children emotions, how to teach them, and similar children’s literature are discussed. Facial expressions and feelings while experiencing an emotion was also researched, which is presented in the creative process. An analysis of the text and illustrations is provided as well.
ContributorsMartinson, Hannah Marie (Author) / Jimenez-Arista, Laura (Thesis director) / Pereira, Jennifer (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2020-12