Matching Items (147)
Description
Woody plant encroachment is a worldwide phenomenon linked to water availability in semiarid systems. Nevertheless, the implications of woody plant encroachment on the hydrologic cycle are poorly understood, especially at the catchment scale. This study takes place in a pair of small semiarid rangeland undergoing the encroachment of Prosopis velutina Woot., or velvet mesquite tree. The similarly-sized basins are in close proximity, leading to equivalent meteorological and soil conditions. One basin was treated for mesquite in 1974, while the other represents the encroachment process. A sensor network was installed to measure ecohydrological states and fluxes, including precipitation, runoff, soil moisture and evapotranspiration. Observations from June 1, 2011 through September 30, 2012 are presented to describe the seasonality and spatial variability of ecohydrological conditions during the North American Monsoon (NAM). Runoff observations are linked to historical changes in runoff production in each watershed. Observations indicate that the mesquite-treated basin generates more runoff pulses and greater runoff volume for small rainfall events, while the mesquite-encroached basin generates more runoff volume for large rainfall events. A distributed hydrologic model is applied to both basins to investigate the runoff threshold processes experienced during the NAM. Vegetation in the two basins is classified into grass, mesquite, or bare soil using high-resolution imagery. Model predictions are used to investigate the vegetation controls on soil moisture, evapotranspiration, and runoff generation. The distributed model shows that grass and mesquite sites retain the highest levels of soil moisture. The model also captures the runoff generation differences between the two watersheds that have been observed over the past decade. Generally, grass sites in the mesquite-treated basin have less plant interception and evapotranspiration, leading to higher soil moisture that supports greater runoff for small rainfall events. For large rainfall events, the mesquite-encroached basin produces greater runoff due to its higher fraction of bare soil. The results of this study show that a distributed hydrologic model can be used to explain runoff threshold processes linked to woody plant encroachment at the catchment-scale and provides useful interpretations for rangeland management in semiarid areas.
ContributorsPierini, Nicole A (Author) / Vivoni, Enrique R (Thesis advisor) / Wang, Zhi-Hua (Committee member) / Mays, Larry W. (Committee member) / Arizona State University (Publisher)
Created2013
Description
Infectious diseases have been a major threat to survival throughout human history. Humans have developed a behavioral immune system to prevent infection by causing individuals to avoid people, food, and objects that could be contaminated. This current project investigates how ambient temperature affects the activation of this system. Because temperature is positively correlated with the prevalence of many deadly diseases, I predict that temperature moderates the behavioral immune system, such that a disease prime will have a stronger effect in a hot environment compared to a neutral environment and one's avoidant behaviors will be more extreme. Participants were placed in a hot room (M = 85F) or a neutral room (M = 77F) and shown a disease prime slide show or a neutral slide show. Disgust sensitivity and perceived vulnerability surveys were used to measure an increased perceived risk to disease. A taste test between a disgusting food item (gummy bugs) and a neutral food item (gummy animals) measured food avoidance. There was no significant avoidance of the gummy and no significant difference in ratings of disgust sensitivity or perceived vulnerability as a function of temperature conditions. There were no significant interactions between temperature and disease. The conclusion is that this study did not provide evidence that temperature moderates the effect of disease cues on behavior.
ContributorsOsborne, Elizabeth (Author) / Cohen, Adam B. (Thesis advisor) / Kwan, Sau (Committee member) / Neuberg, Steven (Committee member) / Arizona State University (Publisher)
Created2012
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 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
Description
Regular instances of employee and petty theft seem to suggest that stealing is common. Certain situations make stealing an advantageous opportunity, and studies show that most people will steal under the right conditions. However, these "right conditions" vary widely among individuals and are a combination of biological, social, psychological, and situational factors. In an attempt to better understand the rationality of stealing, our research team applied evolutionary psychology principles to a social experiment involving gift card theft. To find trends in how people will steal when given the opportunity, we attempted to create these "right conditions" (which we believed would encourage theft by minimizing cost) so that we could measure how a random sample of subjects (male students on the Tempe campus of Arizona State University) responded to variation in benefit. We predicted that if the cost was kept low, and if some gift cards conferred greater advantages than others (by possession greater value or utility), then the more advantageous gift cards would be stolen at a higher frequency from the sample pool than less advantageous ones. The results show that our assumptions were wrong. Theft almost never occurred and the few cards that were stolen were not the more "rational" choices as predicted. The experimental design indicates a flawed understanding of how the subjects weighed the benefits and costs of stealing gift cards. One major issue is that we failed to consider pro-social behavior as the norm. We also neglected the evolutionary benefits of cooperative behavior while overemphasizing the evolutionary benefits of theft. A more thorough and nuanced examination of the literature must be performed to avoid these fundamental flaws in the experiment in the future. The experiment also suffered from issues which might have inadvertently discouraged theft including the location, population, presence of other students, and time given to contemplate theft. If we wish to truly examine trends in theft to see if there is a trend towards the rational theft model we proposed, we must work with a population in which individuals already have a propensity to steal, the benefit is sufficiently high, and social pressures to be cooperative are low.
ContributorsKumar, Davina Sangitha (Author) / Angilletta, Michael (Thesis director) / Neuberg, Steven (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Background: Human papillomavirus (HPV) is the cause of 99.7% of cervical cancers. Research of cervical cancer has made this disease mostly curable in the developing world. Head and neck cancer, which is increasingly caused by HPV, still is associated with a mortality rate of 50,000 in the US annually. This study proposed to evaluate the biology of HPV-16 in head and neck tumors by using RT-qPCR to measure the RNA expression and its relation to physical status of the virus. Methods: This study was to develop an assay that uses RT-qPCR to determine the quantitative expression of HPV-16 RNA coding for proteins E1, E2, E4, E5, E6, and E7 in tumor samples. The assay development started with creation of primers. It went on to test the primers on template DNA through traditional PCR and then on DNA from HPV-16 positive cell lines, SiHa and CaSki, using RT-qPCR. This paper also describes the troubleshooting methods taken for the PCR reaction. Once the primers are verified, the RT-qPCR process can be carried out on RNA purified from tumor samples. Results: No primer sets have been confirmed to produce a product through PCR or RT-qPCR. The primer sequences match up correctly with known sequences for HPV-16 E1, E2, E4, E5, E6, and E7. RT-qPCR showed results consistent with the hypothesis. Conclusion: The RT-qPCR protocol must be optimized to confirm the primer sequences work as desired. Then primers will be used to study physical status and RNA expression in HPV-positive and HPV-negative head and neck tumor samples. This assay can help shed light on which proteins are expressed most in tumors of the head and neck and will aid in the development of future screening and treatment options.
ContributorsKhazanovich, Jakob (Author) / Anderson, Karen (Thesis director) / Mangone, Marco (Committee member) / Sundaresan, Sri Krishna (Committee member) / Barrett, The Honors College (Contributor)
Created2015-05
Description
Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disease characterized by progressive muscle loss and weakness. This disease arises from a mutation that occurs on a gene that encodes for dystrophin, which results in observable muscle death and inflammation; however, the genetic changes that result from dystrophin's dysfunctionality remain unknown. Current DMD research uses mdx mice as a model, and while very useful, does not allow the study of cell-autonomous transcriptome changes during the progression of DMD due to the strong inflammatory response, perhaps hiding important therapeutic targets. C. elegans, which has a very weak inflammatory response compared to mdx mice and humans, has been used in the past to study DMD with some success. The worm ortholog of the dystrophin gene has been identified as dys-1 since its mutation phenocopies the progression of the disease and a portion of the human dystrophin gene alleviates symptoms. Importantly, the extracted RNA transcriptome from dys-1 worms showed significant change in gene expression, which needs to be further investigated with the development of a more robust model. Our lab previously published a method to isolate high-quality muscle-specific RNA from worms, which could be used to study such changes at higher resolution. We crossed the dys-1 worms with our muscle-specific strain and demonstrated that the chimeric strain exhibits similar behavioral symptoms as DMD patients as characterized by a shortened lifespan, difficulty in movement, and a decrease in speed. The presence of dys-1 and other members of the dystrophin complex in the body muscle were supported by the development of a resulting phenotype due to RNAi knockdown of each component in the body muscle; however, further experimentation is needed to reinforce this conclusion. Thus, the constructed chimeric C. elegans strain possesses unique characteristics that will allow the study of genetic changes, such as transcriptome rearrangements and dysregulation of miRNA, and how they affect the progression of DMD.
ContributorsNguyen, Thuy-Duyen Cao (Author) / Mangone, Marco (Thesis director) / Newbern, Jason (Committee member) / Duchaine, Thomas (Committee member) / School of Social Transformation (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Contextual cues can impact how statements are perceived. Specifically, they may be perceived as more aggressive than they otherwise would be. For the study, both medium of communication (in-person versus online) as well as how competitive the context was (non-competitive or competitive) were examined, with a bit of focus on gender. 130 Arizona State University students enrolled in Psychology 101 were surveyed; the mean age was 19.32 (SD = 1.43). A 2x2 factorial design was used, consisting of four possible conditions: In-person/Competitive, Online/Competitive, In-person/Non-Competitive, and Online/Non-Competitive. Participants read two scenarios, each featuring a target character who says an ambiguous statement, and each scenario with one of the four conditions at random. One scenario involved earning a promotion, and the other involved trying to win a voucher via mini-golf. After, participants answered questions regarding how they felt about the intent of the ambiguous statement, how the participant would feel in the scenario, and what kind of person the participant felt the target character was. Exploratory Factor Analysis with Principal Axis Factoring and Direct Oblimin Rotation was used to find outcome variables. We hypothesized that Perceived Aggression and Participant Negative Emotion would be higher in both the competitive condition as well as the online condition, and that Perceived Agreeableness would be higher in both the non-competitive condition as well as the in-person condition; this applied for both scenarios. The results were mostly not statistically significant, and contrary to the hypotheses, Perceived Aggression and Participant Negative Emotion were higher in the in-person condition than the online condition. However, as predicted, Perceived Agreeableness was higher for the in-person condition, and the competitive led to higher levels of Perceived Aggression and Participant Negative Emotion, along with lower levels of Perceived Agreeableness, as opposed to the non-competitive condition. Limitations included a small age range and only one type of online communication (instant messaging), along with the fact that the study was a survey. Future studies are needed to examine what factors affect perception of aggression, as very few have been conducted.
ContributorsRobins, Alexander Eric (Author) / Shiota, Michelle (Lani) (Thesis director) / Neuberg, Steven (Committee member) / Danvers, Alexander (Committee member) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
microRNAs (miRNAs) are short ~22nt non-coding RNAs that regulate gene output at the post-transcriptional level. Via targeting of degenerate elements primarily in 3'untranslated regions (3'UTR) of mRNAs, miRNAs can target thousands of varying genes and suppress their protein translation. The precise mechanistic function and bio- logical role of miRNAs is not fully understood and yet it is a major contributor to a pleth- ora of diseases, including neurological disorders, muscular disorders, and cancer. Cer- tain model organisms are valuable in understanding the function of miRNA and there- fore fully understanding the biological significance of miRNA targeting. Here I report a mechanistic analysis of miRNA targeting in C. elegans, and a bioinformatic approach to aid in further investigation of miRNA targeted sequences. A few of the biologically significant mechanisms discussed in this thesis include alternative polyadenylation, RNA binding proteins, components of the miRNA recognition machinery, miRNA secondary structures, and their polymorphisms. This thesis also discusses a novel bioinformatic approach to studying miRNA biology, including computational miRNA target prediction software, and sequence complementarity. This thesis allows a better understanding of miRNA biology and presents an ideal strategy for approaching future research in miRNA targeting.
ContributorsWeigele, Dustin Keith (Author) / Mangone, Marco (Thesis director) / Katchman, Benjamin (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2014-12
Description
In the current study, the author investigated whether sociosexual orientation interacted with an experimental manipulation of sex ratios previously used by Li et al. (2010) which showed that men and women report greater religiosity after viewing profiles of attractive members of their own sex. The author predicted that only people of restricted sociosexual orientation would be reporting greater religiosity after viewing profiles of attractive members of their own sex. A sample of 171 undergraduate students (85 men, Mage = 19.5) from a large Southwestern university participated in the study for course credit. Participants were first administered the Sociosexual Orientation Index (Simpson & Gangestad, 1991). Then, under the pretense of assisting psychology faculty in designing a dating website for incoming students, participants viewed a set of profiles (photo and description) of either attractive men or attractive women, after which they answered a series of questions on a religiosity scale developed for the current study. Results showed that sociosexual orientation did not interact significantly with the experimental manipulation. Additionally, the results of the current study failed to replicate those of Li et al. (2010). The author discusses possibilities for why the results of the current study failed to replicate the results of Li et al., and for alternative explanations of the potential role of sociosexual orientation in responding to shifting sex ratios.
ContributorsCottengaim, Isaiah John (Author) / Cohen, Adam (Thesis director) / Neuberg, Steven (Committee member) / Barrett, The Honors College (Contributor) / School of Social and Behavioral Sciences (Contributor)
Created2014-05
Description
The Cannabis plant has historical roots with human beings. The plant produces compounds called cannabinoids, which are responsible for the physiological affects of Cannabis and make it a research candidate for medicinal use. Analysis of the plant and its components will help build a better database that could be used to develop a complete roster of medicinal benefits. Research regarding the cellular protein receptors that bind the cannabinoids may not only help provide reasons explaining why the Cannabis plant could be medicinally relevant, but will also help explain how the receptors originated. The receptors may have been present in organisms before the present day Cannabis plant. So why would there be receptors that bind to cannabinoids? Searching for an endocannabinoid system could help explain the purpose of the cannabinoid receptors and their current structures in humans. Using genetic technologies we are able to take a closer look into the evolutionary history of cannabinoids and the receptors that bind them.
ContributorsSalasnek, Reed Samuel (Author) / Capco, David (Thesis director) / Mangone, Marco (Committee member) / Stump, Edmund (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05