Matching Items (362)
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
Description
Honey bee workers display remarkable flexibility in the aging process. This plasticity is closely tied to behavioral maturation. Workers who initiate foraging behavior at earlier ages have shorter lifespans, and much of the variation in total lifespan can be explained by differences in pre-foraging lifespan. Vitellogenin (Vg), a yolk precursor protein, influences worker lifespan both as a regulator of behavioral maturation and through anti-oxidant and immune functions. Experimental reduction of Vg mRNA, and thus Vg protein levels, in wild-type bees results in precocious foraging behavior, decreased lifespan, and increased susceptibility to oxidative damage. We sought to separate the effects of Vg on lifespan due to behavioral maturation from those due to immune and antioxidant function using two selected strains of honey bees that differ in their phenotypic responsiveness to Vg gene knockdown. Surprisingly, we found that lifespans lengthen in the strain described as behaviorally and hormonally insensitive to Vg reduction. We then performed targeted gene expression analyses on genes hypothesized to mediate aging and lifespan: the insulin-like peptides (Ilp1 and 2) and manganese superoxide dismutase (mnSOD). The two honey bee Ilps are the most upstream components in the insulin-signaling pathway, which influences lifespan in Drosophila melanogaster and other organisms, while manganese superoxide dismutase encodes an enzyme with antioxidant functions in animals. We found expression differences in the llps in fat body related to behavior (llp1 and 2) and genetic background (Ilp2), but did not find strain by treatment effects. Expression of mnSOD was also affected by behavior and genetic background. Additionally, we observed a differential response to Vg knockdown in fat body expression of mnSOD, suggesting that antioxidant pathways may partially explain the strain-specific lifespan responses to Vg knockdown.
ContributorsIhle, Kate (Author) / Fondrk, M. Kim (Author) / Page, Robert (Author) / Amdam, Gro (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor)
Created2015-01-01
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