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Description
Biological soil crusts (BSCs), topsoil microbial assemblages typical of arid land ecosystems, provide essential ecosystem services such as soil fertilization and stabilization against erosion. Cyanobacteria and lichens, sometimes mosses, drive BSC as primary producers, but metabolic activity is restricted to periods of hydration associated with precipitation. Climate models for the

Biological soil crusts (BSCs), topsoil microbial assemblages typical of arid land ecosystems, provide essential ecosystem services such as soil fertilization and stabilization against erosion. Cyanobacteria and lichens, sometimes mosses, drive BSC as primary producers, but metabolic activity is restricted to periods of hydration associated with precipitation. Climate models for the SW United States predict changes in precipitation frequency as a major outcome of global warming, even if models differ on the sign and magnitude of the change. BSC organisms are clearly well adapted to withstand desiccation and prolonged drought, but it is unknown if and how an alteration of the precipitation frequency may impact community composition, diversity, and ecosystem functions. To test this, we set up a BSC microcosm experiment with variable precipitation frequency treatments using a local, cyanobacteria-dominated, early-succession BSC maintained under controlled conditions in a greenhouse. Precipitation pulse size was kept constant but 11 different drought intervals were imposed, ranging between 416 to 3 days, during a period of 416 days. At the end of the experiments, bacterial community composition was analyzed by pyrosequencing of the 16s rRNA genes in the community, and a battery of functional assays were used to evaluate carbon and nitrogen cycling potentials. While changes in community composition were neither marked nor consistent at the Phylum level, there was a significant trend of decreased diversity with increasing precipitation frequency, and we detected particular bacterial phylotypes that responded to the frequency of precipitation in a consistent manner (either positively or negatively). A significant trend of increased respiration with increasingly long drought period was detected, but BSC could recover quickly from this effect. Gross photosynthesis, nitrification and denitrification remained essentially impervious to treatment. These results are consistent with the notion that BSC community structure adjustments sufficed to provide significant functional resilience, and allow us to predict that future alterations in precipitation frequency are unlikely to result in severe impacts to BSC biology or ecological relevance.
ContributorsMyers, Natalie Kristine (Author) / Garcia-Pichel, Ferran (Thesis advisor) / Hall, Sharon (Committee member) / Turner, Benjamin (Committee member) / Krajmalnik-Brown, Rosa (Committee member) / Arizona State University (Publisher)
Created2013
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Description
Some cyanobacteria can generate hydrogen (H2) under certain physiological conditions and are considered potential agents for biohydrogen production. However, they also present low amounts of H2 production, a reaction reversal towards H2 consumption, and O2 sensitivity. Most attempts to improve H2 production have involved genetic or metabolic engineering approaches. I

Some cyanobacteria can generate hydrogen (H2) under certain physiological conditions and are considered potential agents for biohydrogen production. However, they also present low amounts of H2 production, a reaction reversal towards H2 consumption, and O2 sensitivity. Most attempts to improve H2 production have involved genetic or metabolic engineering approaches. I used a bio-prospecting approach instead to find novel strains that are naturally more apt for biohydrogen production. A set of 36, phylogenetically diverse strains isolated from terrestrial, freshwater and marine environments were probed for their potential to produce H2 from excess reductant. Two distinct patterns in H2 production were detected. Strains displaying Pattern 1, as previously known from Synechocystis sp. PCC 6803, produced H2 only temporarily, reverting to H2 consumption within a short time and after reaching only moderately high H2 concentrations. By contrast, Pattern 2 cyanobacteria, in the genera Lyngbya and Microcoleus, displayed high production rates, did not reverse the direction of the reaction and reached much higher steady-state H2 concentrations. L. aestuarii BL J, an isolate from marine intertidal mats, had the fastest production rates and reached the highest steady-state concentrations, 15-fold higher than that observed in Synechocystis sp. PCC 6803. Because all Pattern 2 strains originated in intertidal microbial mats that become anoxic in dark, it was hypothesized that their strong hydrogenogenic capacity may have evolved to aid in fermentation of the photosynthate. When forced to ferment, these cyanobacteria display similarly desirable characteristics of physiological H2 production. Again, L. aestuarii BL J had the fastest specific rates and attained the highest H2 concentrations during fermentation, which proceeded via a mixed-acid pathway to yield acetate, ethanol, lactate, H2, CO2 and pyruvate. The genome of L. aestuarii BL J was sequenced and bioinformatically compared to other cyanobacterial genomes to ascertain any potential genetic or structural basis for powerful H2 production. The association hcp exclusively in Pattern 2 strains suggests its possible role in increased H2 production. This study demonstrates the value of bioprospecting approaches to biotechnology, pointing to the strain L. aestuarii BL J as a source of useful genetic information or as a potential platform for biohydrogen production.
ContributorsKothari, Ankita (Author) / Garcia-Pichel, Ferran (Thesis advisor) / Vermaas, Willem F J (Committee member) / Rittmann, Bruce (Committee member) / Torres, Cesar (Committee member) / Arizona State University (Publisher)
Created2013
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Description
In the middle of the 20th century, juried annuals of Native American painting in art museums were unique opportunities because of their select focus on two-dimensional art as opposed to "craft" objects and their inclusion of artists from across the United States. Their first fifteen years were critical for patronage

In the middle of the 20th century, juried annuals of Native American painting in art museums were unique opportunities because of their select focus on two-dimensional art as opposed to "craft" objects and their inclusion of artists from across the United States. Their first fifteen years were critical for patronage and widespread acceptance of modern easel painting. Held at the Philbrook Art Center in Tulsa (1946-1979), the Denver Art Museum (1951-1954), and the Museum of New Mexico Art Gallery in Santa Fe (1956-1965), they were significant not only for the accolades and prestige they garnered for award winners, but also for setting standards of quality and style at the time. During the early years of the annuals, the art was changing, some moving away from conventional forms derived from the early art training of the 1920s and 30s in the Southwest and Oklahoma, and incorporating modern themes and styles acquired through expanded opportunities for travel and education. The competitions reinforced and reflected a variety of attitudes about contemporary art which ranged from preserving the authenticity of the traditional style to encouraging experimentation. Ultimately becoming sites of conflict, the museums that hosted annuals contested the directions in which artists were working. Exhibition catalogs, archived documents, and newspaper and magazine articles about the annuals provide details on the exhibits and the changes that occurred over time. The museums' guidelines and motivations, and the statistics on the award winners reveal attitudes toward the art. The institutions' reactions in the face of controversy and their adjustments to the annuals' guidelines impart the compromises each made as they adapted to new trends that occurred in Native American painting over a fifteen year period. This thesis compares the approaches of three museums to their juried annuals and establishes the existence of a variety of attitudes on contemporary Native American painting from 1946-1960. Through this collection of institutional views, the competitions maintained a patronage base for traditional style painting while providing opportunities for experimentation, paving the way for the great variety and artistic progress of Native American painting today.
ContributorsPeters, Stephanie (Author) / Duncan, Kate (Thesis advisor) / Fahlman, Betsy (Thesis advisor) / Mesch, Claudia (Committee member) / Arizona State University (Publisher)
Created2012
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Description
Future robotic and human missions to the Moon and Mars will need in situ capabilities to characterize the mineralogy of rocks and soils within a microtextural context. Such spatially-correlated information is considered crucial for correct petrogenetic interpretations and will be key observations for assessing the potential for past habitability on

Future robotic and human missions to the Moon and Mars will need in situ capabilities to characterize the mineralogy of rocks and soils within a microtextural context. Such spatially-correlated information is considered crucial for correct petrogenetic interpretations and will be key observations for assessing the potential for past habitability on Mars. These data will also enable the selection of the highest value samples for further analysis and potential caching for return to Earth. The Multispectral Microscopic Imager (MMI), similar to a geologist's hand lens, advances the capabilities of current microimagers by providing multispectral, microscale reflectance images of geological samples, where each image pixel is comprised of a 21-band spectrum ranging from 463 to 1735 nm. To better understand the capabilities of the MMI in future surface missions to the Moon and Mars, geological samples comprising a range of Mars-relevant analog environments as well as 18 lunar rocks and four soils, from the Apollo collection were analyzed with the MMI. Results indicate that the MMI images resolve the fine-scale microtextural features of samples, and provide important information to help constrain mineral composition. Spectral end-member mapping revealed the distribution of Fe-bearing minerals (silicates and oxides), along with the presence of hydrated minerals. In the case of the lunar samples, the MMI observations also revealed the presence of opaques, glasses, and in some cases, the effects of space weathering in samples. MMI-based petrogenetic interpretations compare favorably with laboratory observations (including VNIR spectroscopy, XRD, and thin section petrography) and previously published analyses in the literature (for the lunar samples). The MMI was also deployed as part of the 2010 ILSO-ISRU field test on the slopes of Mauna Kea, Hawaii and inside the GeoLab as part of the 2011 Desert RATS field test at the Black Point Lava Flow in northern Arizona to better assess the performance of the MMI under realistic field conditions (including daylight illumination) and mission constraints to support human exploration. The MMI successfully imaged rocks and soils in outcrops and samples under field conditions and mission operation scenarios, revealing the value of the MMI to support future rover and astronaut exploration of planetary surfaces.
ContributorsNúñez Sánchez, Jorge Iván (Author) / Farmer, Jack D. (Thesis advisor) / Christensen, Philip R. (Committee member) / Garcia-Pichel, Ferran (Committee member) / Robinson, Mark S. (Committee member) / Sellar, R. Glenn (Committee member) / Williams, Lynda B. (Committee member) / Arizona State University (Publisher)
Created2012
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Description
Biological soil crusts (BSCs) are critical components of arid and semiarid environments and provide the primary sources of bioavailable macronutrients and increase micronutrient availability to their surrounding ecosystems. BSCs are composed of a variety of microorganisms that perform a wide range of physiological processes requiring a multitude of bioessential micronutrients,

Biological soil crusts (BSCs) are critical components of arid and semiarid environments and provide the primary sources of bioavailable macronutrients and increase micronutrient availability to their surrounding ecosystems. BSCs are composed of a variety of microorganisms that perform a wide range of physiological processes requiring a multitude of bioessential micronutrients, such as iron, copper, and molybdenum. This work investigated the effects of BSC activity on soil solution concentrations of bioessential elements and examined the microbial production of organic chelators, called siderophores. I found that aluminum, vanadium, copper, zinc, and molybdenum were solubilized in the action of crusts, while nickel, zinc, arsenic, and zirconium were immobilized by crust activity. Potassium and manganese displayed behavior consistent with biological removal and mobilization, whereas phosphorus and iron solubility were dominated by abiotic processes. The addition of bioavailable nitrogen altered the effects of BSCs on soil element mobilization. In addition, I found that the biogeochemical activites of BSCs were limited by molybdenum, a fact that likely contributes to co-limitation by nitrogen. I confirmed the presence of siderophore producing microbes in BSCs. Siderophores are low-molecular weight organic compounds that are released by bacteria to increase element solubility and facilitate element uptake; siderophore production is likely the mechanism by which BSCs affect the patterns I observed in soil solution element concentrations. Siderophore producers were distributed across a range of bacterial groups and ecological niches within crusts, suggesting that siderophore production influences the availability of a variety of elements for use in many physiological processes. Four putative siderophore compounds were identified using electrospray ionization mass spectrometry; further attempts to characterize the compounds confirmed two true siderophores. Taken together, the results of my work provide information about micronutrient cycling within crusts that can be applied to BSC conservation and management. Fertilization with certain elements, particularly molybdenum, may prove to be a useful technique to promote BSC growth and development which would help prevent arid land degradation. Furthermore, understanding the effects of BSCs on soil element mobility could be used to develop useful biomarkers for the study of the existence and distribution of crust-like communities on ancient Earth, and perhaps other places, like Mars.
ContributorsNoonan, Kathryn Alexander (Author) / Hartnett, Hilairy (Thesis advisor) / Anbar, Ariel (Committee member) / Garcia-Pichel, Ferran (Committee member) / Shock, Everett (Committee member) / Sharp, Thomas (Committee member) / Arizona State University (Publisher)
Created2012
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Description

Expectation for college attendance in the United States continues to rise as more jobs require degrees. This study aims to determine how parental expectations affect high school students in their decision to attend college. By examining parental expectations that were placed on current college students prior to and during the

Expectation for college attendance in the United States continues to rise as more jobs require degrees. This study aims to determine how parental expectations affect high school students in their decision to attend college. By examining parental expectations that were placed on current college students prior to and during the application period, we can determine the positive and negative outcomes of these expectations as well as the atmosphere they are creating. To test the hypothesis, an online survey was distributed to current ASU and Barrett, Honors College students regarding their experience with college applications and their parents' influence on their collegiate attendance. A qualitative analysis of the data was conducted in tandem with an analysis of several case studies to determine the results. These data show that parental expectations are having a significant impact on the enrollment of high school students in college programs. With parents placing these expectations on their children, collegiate enrollment will continue to increase. Further studies will be necessary to determine the specific influences these expectations are placing on students.

ContributorsJohnson, Benjamin Howard (Co-author) / Scheller, Sara (Co-author) / Kappes, Janelle (Thesis director) / Fairbanks, Elizabeth (Committee member) / Department of Psychology (Contributor) / School of Social Transformation (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

The purpose of this project was to research the expression of Autism Spectrum Disorder in children and create a children’s book that can help the peers of individuals with a diagnosis to understand what the disorder entails and potentially gain a new sense of empathy for peers of all levels

The purpose of this project was to research the expression of Autism Spectrum Disorder in children and create a children’s book that can help the peers of individuals with a diagnosis to understand what the disorder entails and potentially gain a new sense of empathy for peers of all levels of physical and mental abilities. The research component includes interviews with individuals deemed knowledgeable about ASD, including occupational therapists, behavioral analysts, and parents, as well as a literature review of research studies on the expression of Autism in children. This written portion of the project may also serve as a manual for individuals who have little to no knowledge of ASD, as it dives deeper into the content of the book and research, while remaining easily understandable and clear to those without any prior knowledge or experience with ASD. It could prove especially useful for those in professions that come into contact with individuals with Autism, but do not necessarily require psychology courses or training as a prerequisite for the role, such as teachers and some health professionals.

ContributorsSigna, Hope (Author) / Nelson, Elizabeth (Thesis director) / Spinrad, Tracy (Committee member) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Due to the Covid-19 pandemic, healthcare professionals including occupational therapy practitioners (OTPs) were required to transition to working utilizing an online-service delivery model called telehealth. The use of telehealth for occupational therapy (OT) sessions was limited prior to the pandemic, and this shift required OTPs to provide services in ways

Due to the Covid-19 pandemic, healthcare professionals including occupational therapy practitioners (OTPs) were required to transition to working utilizing an online-service delivery model called telehealth. The use of telehealth for occupational therapy (OT) sessions was limited prior to the pandemic, and this shift required OTPs to provide services in ways many had never experienced. The purpose of this study was to identify how the transition to telehealth impacted OTPs and their ability to provide proper care to the pediatric population via telehealth. The final analytic sample included 32 female OTPs who worked with the pediatric population. Results from qualitative and quantitative analyses showed that OTPs had positive feelings toward using telehealth and that the telehealth modality had a moderate impact on their job performance. The areas that pediatric OTPs want to be addressed included technology and internet issues, lack of parent involvement, decreased quality of care, inaccessibility of materials, decreased attention span and increased distractions, and lack of general knowledge about telehealth among clients, parents, and professionals. Despite these drawbacks, a positive theme emerged that the telehealth model is good for current circumstances. The results show telehealth is a positive experience for OTPs and allows OT to be more accessible to their clients. Implications for increasing education for healthcare professionals, clients, and parents/guardians to make telehealth accessible to clients on a large scale are discussed.

ContributorsMulvaney, Kaitlin Marie (Author) / Bryce, Crystal (Thesis director) / Seeley, Bridget (Committee member) / Sanford School of Social and Family Dynamics (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

The present study explored the relationship between desired purchasing behavior and individual differences using two nationally-representative, longitudinal samples of the U.S. population early in the COVID-19 pandemic. Past research has shown that individual differences provide information about how one might respond to threat. Therefore, we predicted changes in desired purchasing

The present study explored the relationship between desired purchasing behavior and individual differences using two nationally-representative, longitudinal samples of the U.S. population early in the COVID-19 pandemic. Past research has shown that individual differences provide information about how one might respond to threat. Therefore, we predicted changes in desired purchasing behavior across different sociodemographic variables that might reflect those differences. Specifically, we investigated hypotheses related to political orientation, age, sexual orientation, socioeconomic status, and whether or not the participant had children. We measured participants’ reported desired purchasing behavior across eleven categories of goods and investigated the connection between specific demographic variables and desired purchasing behavior. We found that conservatives desired to purchase more basic protection goods (guns/ammunition, cash, gas) and that older people desired to purchase more cleaning supplies and toiletries. These findings illustrate possible explanations for purchasing behavior during the COVID-19 pandemic and reveal directions for marketing designed to influence purchasing behavior.

ContributorsZeider, Justyn (Author) / Varnum, Michael (Thesis director) / Neuberg, Steven (Committee member) / Department of Psychology (Contributor) / School of International Letters and Cultures (Contributor) / School of Social Transformation (Contributor) / Sandra Day O'Connor College of Law (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Introduction. Human papillomavirus (HPV) is the most common sexually transmitted infections globally. HPV is responsible for several health concerns including genital warts, cancer of the cervix, vulva, penis, anus, and oropharynx. In China, HPV infection accounts for 69.1% of invasive cervical cancer. Currently, there is no treatment for HPV infection,

Introduction. Human papillomavirus (HPV) is the most common sexually transmitted infections globally. HPV is responsible for several health concerns including genital warts, cancer of the cervix, vulva, penis, anus, and oropharynx. In China, HPV infection accounts for 69.1% of invasive cervical cancer. Currently, there is no treatment for HPV infection, but HPV vaccination has been proven to be effective against HPV-related diseases. Given the highest rate of contracting HPV and suboptimal vaccination rate in college students including international students in the U.S., it is important to investigate key factors associated with vaccine uptake among Chinese international students. Purpose. This study aimed to investigate knowledge and awareness of HPV and the vaccine, attitudes, and vaccination intention in this population. We conducted a cross-sectional online survey via REDCap. Methods. Participants who were (1) Chinese international student at Arizona State University; (2) 18 and older; (3) able to read, speak and write in Chinese or English were recruited from Arizona State University. Descriptive statistics (mean, standard deviation, frequency) and inferential statistics (Chi-square test, independent t-test) were conducted using SPSS 26.0. Results. One hundred and ten participants were included in this study (56.4% female, mean age = 24, SD = 3.7). Female students had significantly higher HPV vaccination rate than males (p = 0.000). The mean knowledge score was 8.09 (SD = 1.35); female students were more likely to receive HPV education than males (p = 0.001). The most common source of education was friends (50.7%). Three most common perceived risks were not being sexually active, being male, and not having any physical signs and symptoms. The three most common facilitators were infection prevention, access to vaccination, and ability to afford vaccination. The three most common barriers were the cost, safety, and efficacy of HPV vaccine. In conclusion, gender disparities exist among Chinese<br/>international students’ HPV vaccine uptake and HPV related education. Implication. Although Chinese international students possess moderate to high level of knowledge about HPV and HPV vaccines, they lack education from credible sources. Culturally and gender appropriate education is needed in order to address barriers of getting HPV vaccination.

ContributorsChen, Weiqi (Author) / Chen, Angela Chia-Chen (Thesis director) / Reifsnider, Elizabeth (Committee member) / Han, SeungYong (Committee member) / Edson College of Nursing and Health Innovation (Contributor, Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05