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- Creators: Arizona State University
Description
The relationship between biodiversity and ecosystem functioning (BEF) is a central issue in ecology, and a number of recent field experimental studies have greatly improved our understanding of this relationship. Spatial heterogeneity is a ubiquitous characterization of ecosystem processes, and has played a significant role in shaping BEF relationships. The first step towards understanding the effects of spatial heterogeneity on the BEF relationships is to quantify spatial heterogeneity characteristics of key variables of biodiversity and ecosystem functioning, and identify the spatial relationships among these variables. The goal of our research was to address the following research questions based on data collected in 2005 (corresponding to the year when the initial site background information was conducted) and in 2008 (corresponding to the year when removal treatments were conducted) from the Inner Mongolia Grassland Removal Experiment (IMGRE) located in northern China: 1) What are the spatial patterns of soil nutrients, plant biodiversity, and aboveground biomass in a natural grassland community of Inner Mongolia, China? How are they related spatially? and 2) How do removal treatments affect the spatial patterns of soil nutrients, plant biodiversity, and aboveground biomass? Is there any change for their spatial correlations after removal treatments? Our results showed that variables of biodiversity and ecosystem functioning in the natural grassland community would present different spatial patterns, and they would be spatially correlated to each other closely. Removal treatments had a significant effect on spatial structures and spatial correlations of variables, compared to those prior to the removal treatments. The differences in spatial pattern of plant and soil variables and their correlations before and after the biodiversity manipulation may not imply that the results from BEF experiments like IMGRE are invalid. However, they do suggest that the possible effects of spatial heterogeneity on the BEF relationships should be critically evaluated in future studies.
ContributorsYuan, Fei (Author) / Wu, Jianguo (Thesis advisor) / Smith, Andrew T. (Committee member) / Rowe, Helen I (Committee member) / Arizona State University (Publisher)
Created2011
Description
While the literature on caregivers of loved ones with Alzheimer's Disease and Related Disorders (ADRD) has continued to grow, the relationship of ethnicity and acculturation factors with regards to the coping strategies used by caregivers has not been extensively explored. The current study included participants from the Palo Alto site of the Resources for Enhancing Alzheimer's Caregiver Health (REACH) project. The study examined differences in coping strategies between 140 non-Hispanic White, 45 less acculturated Latina, and 61 more acculturated Latina caregivers. Univariate and Multivariate Analysis of Variance, as well as post hoc analyses, were conducted to determine the differences among the three groups. Results indicated less acculturated Latina caregivers employ more avoidant coping strategies compared to non-Hispanic White caregivers. However, no differences were found among the other groups in their use of avoidance coping. Moreover, there were no differences found in the use of social support seeking, count your blessings, problem focused, and blaming others coping among the three groups. These findings have important implications for the design of culturally relevant psychoeducational and therapeutic interventions aimed towards meeting the individual needs of these three populations. In addition, the findings expand on the understanding of maladaptive coping strategies that may be potentially exacerbating caregiver distress among Latina caregivers.
ContributorsFelix, Vitae (Author) / Arciniega, Guillermo M (Thesis advisor) / Robinson-Kurpius, Sharon (Committee member) / Coon, David W. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Emergent environmental issues, ever-shrinking petroleum reserves, and rising fossil fuel costs continue to spur interest in the development of sustainable biofuels from renewable feed-stocks. Meanwhile, however, the development and viability of biofuel fermentations remain limited by numerous factors such as feedback inhibition and inefficient and generally energy intensive product recovery processes. To circumvent both feedback inhibition and recovery issues, researchers have turned their attention to incorporating energy efficient separation techniques such as adsorption in in situ product recovery (ISPR) approaches. This thesis focused on the characterization of two novel adsorbents for the recovery of alcohol biofuels from model aqueous solutions. First, a hydrophobic silica aerogel was evaluated as a biofuel adsorbent through characterization of equilibrium behavior for conventional second generation biofuels (e.g., ethanol and n-butanol). Longer chain and accordingly more hydrophobic alcohols (i.e., n-butanol and 2-pentanol) were more effectively adsorbed than shorter chain alcohols (i.e., ethanol and i-propanol), suggesting a mechanism of hydrophobic adsorption. Still, the adsorbed alcohol capacity at biologically relevant conditions were low relative to other `model' biofuel adsorbents as a result of poor interfacial contact between the aqueous and sorbent. However, sorbent wettability and adsorption is greatly enhanced at high concentrations of alcohol in the aqueous. Consequently, the sorbent exhibits Type IV adsorption isotherms for all biofuels studied, which results from significant multilayer adsorption at elevated alcohol concentrations in the aqueous. Additionally, sorbent wettability significantly affects the dynamic binding efficiency within a packed adsorption column. Second, mesoporous carbons were evaluated as biofuel adsorbents through characterization of equilibrium and kinetic behavior. Variations in synthetic conditions enabled tuning of specific surface area and pore morphology of adsorbents. The adsorbed alcohol capacity increased with elevated specific surface area of the adsorbents. While their adsorption capacity is comparable to polymeric adsorbents of similar surface area, pore morphology and structure of mesoporous carbons greatly influenced adsorption rates. Multiple cycles of adsorbent regeneration rendered no impact on adsorption equilibrium or kinetics. The high chemical and thermal stability of mesoporous carbons provide potential significant advantages over other commonly examined biofuel adsorbents. Correspondingly, mesoporous carbons should be further studied for biofuel ISPR applications.
ContributorsLevario, Thomas (Author) / Nielsen, David R (Thesis advisor) / Vogt, Bryan D (Committee member) / Lind, Mary L (Committee member) / Arizona State University (Publisher)
Created2011
Description
This dissertation provides a fundamental understanding of the impact of bulk polymer properties on the nanometer length scale modulus. The elastic modulus of amorphous organic thin films is examined using a surface wrinkling technique. Potential correlations between thin film behavior and intrinsic properties such as flexibility and chain length are explored. Thermal properties, glass transition temperature (Tg) and the coefficient of thermal expansion, are examined along with the moduli of these thin films. It is found that the nanometer length scale behavior of flexible polymers correlates to its bulk Tg and not the polymers intrinsic size. It is also found that decreases in the modulus of ultrathin flexible films is not correlated with the observed Tg decrease in films of the same thickness. Techniques to circumvent reductions from bulk modulus were also demonstrated. However, as chain flexibility is reduced the modulus becomes thickness independent down to 10 nm. Similarly for this series minor reductions in Tg were obtained. To further understand the impact of the intrinsic size and processing conditions; this wrinkling instability was also utilized to determine the modulus of small organic electronic materials at various deposition conditions. Lastly, this wrinkling instability is exploited for development of poly furfuryl alcohol wrinkles. A two-step wrinkling process is developed via an acid catalyzed polymerization of a drop cast solution of furfuryl alcohol and photo acid generator. The ability to control the surface topology and tune the wrinkle wavelength with processing parameters such as substrate temperature and photo acid generator concentration is also demonstrated. Well-ordered linear, circular, and curvilinear patterns are also obtained by selective ultraviolet exposure and polymerization of the furfuryl alcohol film. As a carbon precursor a thorough understanding of this wrinkling instability can have applications in a wide variety of technologies.
ContributorsTorres, Jessica (Author) / Vogt, Bryan D (Thesis advisor) / Stafford, Christopher M (Committee member) / Richert, Ranko (Committee member) / Rege, Kaushal (Committee member) / Dai, Lenore (Committee member) / Arizona State University (Publisher)
Created2011
Description
Bioparticles comprise a diverse amount of materials ubiquitously present in nature. From proteins to aerosolized biological debris, bioparticles have important roles spanning from regulating cellular functions to possibly influencing global climate. Understanding their structures, functions, and properties provides the necessary tools to expand our fundamental knowledge of biological systems and exploit them for useful applications. In order to contribute to this efforts, the work presented in this dissertation focuses on the study of electrokinetic properties of liposomes and novel applications of bioaerosol analysis. Using immobilized lipid vesicles under the influence of modest (less than 100 V/cm) electric fields, a novel strategy for bionanotubule fabrication with superior throughput and simplicity was developed. Fluorescence and bright field microscopy was used to describe the formation of these bilayer-bound cylindrical structures, which have been previously identified in nature (playing crucial roles in intercellular communication) and made synthetically by direct mechanical manipulation of membranes. In the biological context, the results of this work suggest that mechanical electrostatic interaction may play a role in the shape and function of individual biological membranes and networks of membrane-bound structures. A second project involving liposomes focused on membrane potential measurements in vesicles containing trans-membrane pH gradients. These types of gradients consist of differential charge states in the lipid bilayer leaflets, which have been shown to greatly influence the efficacy of drug targeting and the treatment of diseases such as cancer. Here, these systems are qualitatively and quantitatively assessed by using voltage-sensitive membrane dyes and fluorescence spectroscopy. Bioaerosol studies involved exploring the feasibility of a fingerprinting technology based on current understanding of cellular debris in aerosols and arguments regarding sampling, sensitivity, separations and detection schemes of these debris. Aerosolized particles of cellular material and proteins emitted by humans, animals and plants can be considered information-rich packets that carry biochemical information specific to the living organisms present in the collection settings. These materials could potentially be exploited for identification purposes. Preliminary studies evaluated protein concentration trends in both indoor and outdoor locations. Results indicated that concentrations correlate to certain conditions of the collection environment (e.g. extent of human presence), supporting the idea that bioaerosol fingerprinting is possible.
ContributorsCastillo Gutiérrez, Josemar Andreina (Author) / Hayes, Mark A. (Thesis advisor) / Herckes, Pierre (Committee member) / Ghrilanda, Giovanna (Committee member) / Arizona State University (Publisher)
Created2011
Description
In countries of conflict, non-governmental organizations (NGOs) often resort to humanitarian relief. A small number of peace and conflict resolution organizations (P/CROs) engage more directly, through grassroots mediation, elite negotiation and advocacy. This thesis observes the potential for implementing such direct conflict interventions in traditional relief and development organizations. To understand current NGO activities, I examine ten case study organizations in two countries of conflict, Cote d'Ivoire and Somalia. I analyze organizations' rhetorical presentation, their society-level engagement, strategies for intervention, and responses to persistent challenges, such as security, impartiality, collaboration and evaluation. Based on conflict study literature, I make tentative recommendations for NGOs in Cote d'Ivoire and Somalia specifically. I also propose a more general system for classifying NGO peace work: five generations of conflict intervention, each more integrated, direct, and political. Rhetorical, structural and operational changes will help organizations move toward higher generation work.
ContributorsDiddams, Margaret (Author) / Ron, Amit (Thesis advisor) / Friedrich, Patricia (Thesis advisor) / Wang, Lili (Committee member) / Arizona State University (Publisher)
Created2011
Description
The current study explored whether intrinsically religious individuals are able to separate the "sin" from the "sinner" (i.e., separate category membership from behavior) when judging homosexual individuals, or whether they are instead subject to the negativity bias (judgments based solely on category membership) in moral judgments. All effects were expected to occur only for participants high in homophobia. Participants were 305 undergraduate male and female students at a large, public university in the southwestern U.S. Respondents read one of five scenarios that described gay or straight targets who were celibate or engaged in same or opposite sex relationships, then were asked to respond to a series of questions evaluating attitudes and behavioral intentions toward the target. Results revealed that homophobia led to a negativity bias in judgments of gay targets, which was intensified by intrinsic religiosity. However, individuals high on intrinsic religiosity and high on homophobia also differentiated between gay targets based on sexual behavior, such that gay targets who were celibate or in an opposite-sex relationship were rated more favorably than gay targets in a same-sex relationship. These findings demonstrate that the negativity bias and "sin vs. sinner" differentiation may both be occurring for intrinsically religious individuals. The moderating effect of homophobia on the interaction between intrinsic religiosity and judgments of gay and straight targets shows us that religiosity itself is not inherently tolerant or intolerant.
ContributorsFilip-Crawford, Gabrielle (Author) / Nagoshi, Craig T. (Thesis advisor) / Kwan, Virginia S.Y. (Committee member) / Neuberg, Steven L. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Dynamic loading is the term used for one way of optimally loading a transformer. Dynamic loading means the utility takes into account the thermal time constant of the transformer along with the cooling mode transitions, loading profile and ambient temperature when determining the time-varying loading capability of a transformer. Knowing the maximum dynamic loading rating can increase utilization of the transformer while not reducing life-expectancy, delaying the replacement of the transformer. This document presents the progress on the transformer dynamic loading project sponsored by Salt River Project (SRP). A software application which performs dynamic loading for substation distribution transformers with appropriate transformer thermal models is developed in this project. Two kinds of thermal hottest-spot temperature (HST) and top-oil temperature (TOT) models that will be used in the application--the ASU HST/TOT models and the ANSI models--are presented. Brief validations of the ASU models are presented, showing that the ASU models are accurate in simulating the thermal processes of the transformers. For this production grade application, both the ANSI and the ASU models are built and tested to select the most appropriate models to be used in the dynamic loading calculations. An existing application to build and select the TOT model was used as a starting point for the enhancements developed in this work. These enhancements include: Adding the ability to develop HST models to the existing application, Adding metrics to evaluate the models accuracy and selecting which model will be used in dynamic loading calculation Adding the capability to perform dynamic loading calculations, Production of a maximum dynamic load profile that the transformer can tolerate without acceleration of the insulation aging, Provide suitable output (plots and text) for the results of the dynamic loading calculation. Other challenges discussed include: modification to the input data format, data-quality control, cooling mode estimation. Efforts to overcome these challenges are discussed in this work.
ContributorsLiu, Yi (Author) / Tylavksy, Daniel J (Thesis advisor) / Karady, George G. (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2011
Description
Virtue was a concept of paramount importance in the American founders' republican thought. Without virtue, there could be no liberty, no order, no devotion to the common good, and no republican government. This dissertation examines the concept of virtue at the American founding, particularly virtue in the political thought of Mercy Otis Warren (1728-1814). The most important female intellectual of the Revolutionary generation, Warren wrote passionately about liberty and the beauty of republican ideals. Most important to this study, she consistently advocated the central place of virtue in a free and well-ordered republic. I argue that Warren incorporates three distinct philosophical threads - classical, bourgeois-marketplace, and Christian ideals - in her conception of virtue. I first analyze how Warren uses each of these three threads of virtue throughout her writings. I then examine how she synthesizes these individual threads into a single, cohesive conception of virtue. I argue that Warren consistently merges these ideals into a conception of virtue that she employs to address three pressing political problems of her day: How to motivate reluctant colonists to seek independence; how to check various forms of corruption spreading among the people; and how to counter corruption arising from commercial growth in the new nation. Modern political theorists often argue that these three threads, especially the classical republican and Christian ideals of virtue, are irreconcilable. My analysis shows that to divorce virtue from Christianity in Warren's conception is to rob it of its corrective vigor within republican government. I argue that what Machiavelli and Rousseau wrote out of republican virtue Warren writes back in. In Warren's political thought, virtue serves as the foundation for a stable enduring political system, provides the necessary informal ordering principle for the emerging republic, and offers the means by which the new nation could achieve its millennial destiny.
ContributorsMunsil, Tracy F (Author) / Ball, Terence (Thesis advisor) / Dagger, Richard (Thesis advisor) / Crittenden, William J. (Committee member) / Arizona State University (Publisher)
Created2011
Description
There has been a push to create and implement school wellness policies. Childhood obesity statistics suggest that schools may have an important role to play in promoting wellness. Childhood obesity has become a significant problem in the United States. The percentage of obese children in the United States has more than doubled since 1970, and up to 33% of the children in the United States are currently overweight. Among the 33% of children who are overweight, 25% are obese, and 14% have type 2 diabetes, previously considered to be a condition found only in adults. This mixed-method study with a string qualitative component study examined three aspects of federally mandated local wellness polices. The study investigated the policies themselves, how the policies are understood in the local school setting, with a particular focus on the impact the policies have had on school meals. The bulk of the research data was generated through 8 in-depth interviews. The interviews were conducted with key stakeholders within 2 elementary school districts in Arizona. In addition, the evaluation of 20 local wellness polices was conducted via a rubric scoring system. The primary component found to be lacking in local wellness policies was the evaluation method. Recommendations for school districts include the establishment of a clear method of measurement.
ContributorsCrawford, Sara S (Author) / Mccarty, Teresa L. (Thesis advisor) / Molnar, Alex (Thesis advisor) / Montoya, Araceli (Committee member) / Arizona State University (Publisher)
Created2011