Matching Items (1,262)
Description
Theories of interval timing have largely focused on accounting for the aggregate properties of behavior engendered by periodic reinforcement, such as sigmoidal psychophysical functions and their scalar property. Many theories of timing also stipulate that timing and motivation are inseparable processes. Such a claim is challenged by fluctuations in and out of states of schedule control, making it unclear whether motivation directly affects states related to timing. The present paper seeks to advance our understanding of timing performance by analyzing and comparing the distribution of latencies and inter-response times (IRTs) of rats in two fixed-interval (FI) schedules of food reinforcement (FI 30-s and FI 90-s), and in two levels of food deprivation. Computational modeling revealed that each component was well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed that only a subset of latencies are sensitive to the periodicity of reinforcement, and pre-feeding only reduces the size of this subset. The distribution of IRTs suggests that behavior in FI schedules is organized in bouts that lengthen and ramp up in frequency with proximity to reinforcement. Pre-feeding slowed down the lengthening of bouts and increased the time between bouts. When concatenated, these models adequately reproduced sigmoidal FI response functions. These findings suggest that behavior in FI fluctuates in and out of schedule control; an account of such fluctuation suggests that timing and motivation are dissociable components of FI performance. These mixture-distribution models also provide novel insights on the motivational, associative, and timing processes expressed in FI performance, which need to be accounted for by causal theories of interval timing.
ContributorsDaniels, Carter W (Author) / Sanabria, Federico (Thesis advisor) / Brewer, Gene (Committee member) / Wynne, Clive (Committee member) / Arizona State University (Publisher)
Created2015
Description
Temporal bisection is a common procedure for the study of interval timing in humans and non-human animals, in which participants are trained to discriminate between a “short” and a “long” interval of time. Following stable and accurate discrimination, unreinforced probe intervals between the two values are tested. In temporal bisection studies, intermediate non-reinforced probe intervals are typically arithmetically- or geometrically- spaced, yielding point of subjective equality at the arithmetic and geometric mean of the trained anchor intervals. Brown et al. (2005) suggest that judgement of the length of an interval, even when not reinforced, is influenced by its subjective length in comparison to that of other intervals. This hypothesis predicts that skewing the distribution of probe intervals shifts the psychophysical function relating interval length to the probability of reporting that interval as “long.” Data from the present temporal bisection study, using rats, suggest that there may be a within-session shift in temporal bisection responding which accounts for observed shifts in the psychophysical functions, and that this may also influence how rats categorize ambiguous intervals.
ContributorsGupta, Tanya A. (Author) / Sanabria, Federico (Thesis advisor) / Wynne, Clive (Committee member) / McBeath, Michael (Committee member) / Arizona State University (Publisher)
Created2019
Description
The present series of studies examined whether a novel implementation of an
intermittent restraint (IR) chronic stress paradigm could be used to investigate hippocampal-dependent spatial ability in both sexes. In experiments 1 and 2, Sprague- Dawley male rats were used to identify the optimal IR parameters to assess spatial ability. For IR, rats were restrained for 2 or 6hrs/day (IR2, IR6, respectively) for five days and then given two days off, a process that was repeated for three weeks and compared to rats restrained for 6hrs/d for each day (DR6) and non-stressed controls (CON). Spatial memory was tested on the radial arm water maze (RAWM), object placement (OP), novel object recognition (NOR) and Y-maze. The results for the first two experiments revealed that IR6, but not IR2, was effective in impairing spatial memory in male rats and that task order impacted performance. In experiment 3, an extended IR paradigm for six weeks was implemented before spatial memory testing commenced in male and female rats (IR- M, IR-F). Unexpectedly, an extended IR paradigm failed to impair spatial memory in either males or females, suggesting that when extended, the IR paradigm may have become predictable. In experiment 4, an unpredictable IR (UIR) paradigm was implemented, in which restraint duration (30 or 60-min) combined with orbital shaking, time of day, and the days off from UIR were varied. UIR impaired spatial memory in males, but not females. Together with other reports, these findings support the interpretation that chronic stress negatively impairs hippocampal-dependent function in males, but not females, and that females appear to be resilient to spatial memory deficits in the face of chronic stress.
intermittent restraint (IR) chronic stress paradigm could be used to investigate hippocampal-dependent spatial ability in both sexes. In experiments 1 and 2, Sprague- Dawley male rats were used to identify the optimal IR parameters to assess spatial ability. For IR, rats were restrained for 2 or 6hrs/day (IR2, IR6, respectively) for five days and then given two days off, a process that was repeated for three weeks and compared to rats restrained for 6hrs/d for each day (DR6) and non-stressed controls (CON). Spatial memory was tested on the radial arm water maze (RAWM), object placement (OP), novel object recognition (NOR) and Y-maze. The results for the first two experiments revealed that IR6, but not IR2, was effective in impairing spatial memory in male rats and that task order impacted performance. In experiment 3, an extended IR paradigm for six weeks was implemented before spatial memory testing commenced in male and female rats (IR- M, IR-F). Unexpectedly, an extended IR paradigm failed to impair spatial memory in either males or females, suggesting that when extended, the IR paradigm may have become predictable. In experiment 4, an unpredictable IR (UIR) paradigm was implemented, in which restraint duration (30 or 60-min) combined with orbital shaking, time of day, and the days off from UIR were varied. UIR impaired spatial memory in males, but not females. Together with other reports, these findings support the interpretation that chronic stress negatively impairs hippocampal-dependent function in males, but not females, and that females appear to be resilient to spatial memory deficits in the face of chronic stress.
ContributorsPeay, Dylan (Author) / Conrad, Cheryl D. (Thesis advisor) / Bimonte-Nelson, Heather A. (Committee member) / Wynne, Clive (Committee member) / Arizona State University (Publisher)
Created2019
Description
The purpose of this study was to create a screening tool specifically for the identification of sex trafficking victims in the medical setting through the analysis of existing human trafficking screening tool studies geared towards use in the medical setting. Screening questions from these studies were compiled and modified into a survey that was distributed to healthcare professionals through the nationwide HEAL (Health Professional Education, Advocacy, Linkage) Trafficking listserv. Each screening tool study demonstrated benefits and disadvantages that were helpful in the sampling and selection of screening tool questions. The small sample size and a lack of data on the attitudes of medical professionals on sex trafficked victims were noted as limitations to this study. Further implications for this study would include validating the screening tool questions in a medical setting to determine the sensitivity of the survey in identifying patients as possible sex trafficking victims.
ContributorsCatano, Karen Samantha (Co-author) / Byun, Jiwon (Co-author) / Roe-Sepowitz, Dominique (Thesis director) / Lee, Maurice (Committee member) / School for the Science of Health Care Delivery (Contributor) / College of Integrative Sciences and Arts (Contributor) / W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Due to artificial selection, dogs have high levels of phenotypic diversity, yet, there appears to be low genetic diversity within individual breeds. Through their domestication from wolves, dogs have gone through a series of population bottlenecks, which has resulted in a reduction in genetic diversity, with a large amount of linkage disequilibrium and the persistence of deleterious mutations. This has led to an increased susceptibility to a multitude of diseases, including cancer. To study the effects of artificial selection and life history characteristics on the risk of cancer mortality, we collected cancer mortality data from four studies as well as the percent of heterozygosity, body size, lifespan and breed group for 201 dog breeds. We also collected specific types of cancer breeds were susceptible to and compared the dog cancer mortality patterns to the patterns observed in other mammals. We found a relationship between cancer mortality rate and heterozygosity, body size, lifespan as well as breed group. Higher levels of heterozygosity were also associated with longer lifespan. These results indicate larger breeds, such as Irish Water Spaniels, Flat-coated Retrievers and Bernese Mountain Dogs, are more susceptible to cancer, with lower heterozygosity and lifespan. These breeds are also more susceptible to sarcomas, as opposed to carcinomas in smaller breeds, such as Miniature Pinschers, Chihuahuas, and Pekingese. Other mammals show that larger and long-lived animals have decreased cancer mortality, however, within dog breeds, the opposite relationship is observed. These relationships could be due to the trade-off between cellular maintenance and growing fast and large, with higher expression of growth factors, such as IGF-1. This study further demonstrates the relationships between cancer mortality, heterozygosity, and life history traits and exhibits dogs as an important model organism for understanding the relationship between genetics and health.
ContributorsBalsley, Cassandra Sierra (Author) / Maley, Carlo (Thesis director) / Wynne, Clive (Committee member) / Tollis, Marc (Committee member) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Insects have intricate systems they depend on for survival. They live in societies where every individual plays an important role. Ants are a great example of this observation. They are known for having structurally sound societies that ensure the livelihood of the colony. The ant species analyzed for this research, Harpegnathos saltator, portrays a structured colony and serves as a useful example of levels of hierarchy. In the colony of H. saltator, one can find a queen, gamergates, workers, and male ants living underground in Southern India. Recording and analyzing egg-laying rates are important in this study because of the amount of information it provides. It is used especially when observing the relationship among the gamergates in colonies with varying colony sizes. Three different methods were used to record the egg-laying rates, each providing insight into valuable information. Results show that the smaller colonies with fewer identified gamergates do share an equal amount of egg-laying. In larger colonies, it appears that there are more active identified gamergates than others. Egg-laying duration times are smaller in colonies with fewer gamergates. It is also found that the presence of brood does not affect egg-laying rates and reproductive inhibition could be a possibility based on two of the colonies observed F65 and F21. Based on the data found, a more active colony that attempts to maintain stability by demonstrating aggression may be affecting the reproduction of gamergates. Future work that would further strengthen the research and conclusions made would involve further observation of colonies, both large and small, with varying numbers of gamergates. More observation involving behavior among gamergates and workers would also be beneficial. Mathematical modeling could also be incorporated to create equations that could determine information about colonies based on size, number of gamergates, and egg-laying rates.
ContributorsMayoral, Alejandra (Author) / Kang, Yun (Thesis director) / Liebig, Juergen (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
INTRODUCTION: This thesis delves into how PR-media relations evolved in the past 20 years (since 1997). It discusses several aspects of media relations, such as relationships, old and new media relations tools, pitching and predictions about the future of media relations. LITERATURE REVIEW: A review of previous literature on media relations guided this research. Past research explained stigmas about the relationship between public relations professionals and journalists, how pitching has evolved, social media's role in modern day media relations and the dynamic between earned and owned media. METHODOLOGY: The research involved a mixed method approach with qualitative and quantitative methods. First, in-depth interviews were conducted with both journalists and public relations professionals who work in Arizona. These interviews were conducted either in-person or over the phone. Second, two in-depth interviews were conducted over the phone with a public relations professional who worked at Intel for over 20 years for a case study. Finally, a survey was distributed to public relations professionals in Arizona via email and through social media websites (Facebook and Twitter) to provide insight on the media relations tactics they have recently utilized, as well as their use of social media. There were also five follow-up interviews conducted with survey respondents. FINDINGS: After conducting these three methods of research, the qualitative (quotes) and quantitative (survey) data were analyzed to provide detailed opinions about media relations including: the relationships between public relations professionals and the media, the use of old and new media relations tools, what an effective pitch looks like, the use of social media, comparisons between less and more experienced PR professionals, and predictions on the future of media relations. DISCUSSION: The findings from this research led to several conclusions regarding media relations such as: the importance of maintaining a trusting and respectful relationship, traditional tools' place in modern day media relations, email's dominance as a media relations tool, the hesitation by PR professionals to use social media as a communication tool with journalists, more experienced PR professionals' lack of hesitation to use social media as a communication tool with journalists, and the prediction that relationships will remain key in media relations despite the changes in media relations tools themselves. CONCLUSION: Based on all of the findings from this research, it was concluded that media relations has evolved to keep up with the changing media landscape, however, traditional tools and practices remain relevant and essential to media relations.
ContributorsTillman, Krista Michelle (Author) / Wu, Xu (Thesis director) / Bovio, Sonia (Committee member) / College of Integrative Sciences and Arts (Contributor) / Walter Cronkite School of Journalism and Mass Communication (Contributor) / Department of Marketing (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
Dogs' health and wellbeing is of great importance to their owners. The most common nutritional problem for pet dogs is obesity, with 22-40% of pet dogs being classified as overweight or obese. With many adverse health effects associated with obesity, this is a major concern for owners and veterinarians. The degree to which dogs enjoy consuming certain foods can have substantial implications for their body weight, so it is important to understand which aspects of foods make them appealing to dogs. This study aimed to determine whether nutritional aspects of commercial dog foods predict dogs' preferences for those foods. It was found that consumption preference is positively correlated with protein content (p < .001), therefore implying that the protein content of commercial dry dog foods may predict dogs' consumption preferences. Consumption preferences were not predicted by other available measures of food content or caloric value. Dogs' preference for foods high in protein content may be due to the satiating effect of protein. Since foods high in protein both reduce the amount of energy consumed and are found to be palatable to dogs, high-protein dog foods may offer a way for dog food manufacturers, veterinarians, and pet owners to combat obesity in pet dogs.
ContributorsPrevost, Emily Danielle (Author) / Wynne, Clive (Thesis director) / Hall, Nathaniel (Committee member) / School of Life Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Vitamins and minerals are, by definition, essential substances that are necessary for good health, and needed by every cell and organ to function appropriately. A deficiency of any one vitamin or mineral can be very serious. Although a very healthy diet rich in vegetables, fruits, and protein can provide sufficient amounts of most vitamins and minerals, many people do not consume an adequate diet. During pregnancy, there is an increased need for vitamins and minerals to promote a healthy pregnancy and a healthy baby. Prenatal supplements are intended to supplement a normal diet to ensure that adequate amounts of vitamins and minerals are consumed. The US Food and Drug Administration (FDA) has established Recommended Dietary Allowances for total vitamin/mineral intake from food and supplements, but they have not established recommendations for prenatal supplements. Therefore, there is a very wide variation in the content and quality of prenatal supplements. Many prenatal supplements contain only minimal levels of some vitamins and few or no minerals, in order to minimize cost and the number of pills. This results in insufficient vitamin/mineral supplementation for many women, and hence does not fully protect them or their children from pregnancy complications and health problems. Therefore, we have created our own set of recommendations for prenatal supplements. Our recommendations are based primarily on four sources: 1) FDA's Recommended Daily Allowances for pregnant women, which are estimated to meet the needs of 97.5% of healthy pregnant women. 2) FDA's Tolerable Upper Limit, which is the maximum amount of vitamins/minerals that can be safely consumed without any risk of health problems. 3) National Health and Nutrition Examination Survey (NHANES), which evaluates the average intake of vitamins and minerals by women ages 20-40 years in the US 4) Research studies on vitamin/mineral deficiencies or vitamin/mineral supplementation during pregnancy, and the effect on pregnancy, birth, and child health problems. In summary, the RDA establishes minimum recommended levels of vitamin/mineral intake from all sources, and the NHANES establishes the average intake from foods. The difference is what needs to be consumed in a supplement, on average. However, since people vary greatly in the quality of their diet, and since most vitamins and minerals have a high Tolerable Upper Limit, we generally recommend more than the difference between the RDA and the average NHANES. Vitamins generally have a larger Tolerable Upper Limit than do minerals. So, we recommend that prenatal vitamin/mineral supplements contain 100% of the RDA for most vitamins, and about 50% of the RDA for most minerals. However, based on additional research studies described below, in some cases we vary our recommendations from those averages.
ContributorsSorenson, Jacob (Author) / Adams, James (Thesis director) / Pollard, Elena (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Modeling sporadic amyotrophic lateral sclerosis (sALS) has been a challenge since there is no known single gene mutation that triggers disease pathogenesis. Although human induced pluripotent stem cells (hiPSCs) have created new opportunities in studying sALS, they do not retain important age associated phenotypic markers due to the rejuvenation stage that takes place during the reprogramming of somatic cells into hiPSCs. To overcome this obstacle, we performed an alternative method of direct neuronal conversion from patient fibroblasts that utilizes two transcription factors, Ngn2 and Ascl1. These transcription factors were sufficient to initiate direct neuronal conversion and produce induced neurons (iNeurons). Through the positive staining of neuronal markers Map2, Synapsin-1, and Human Nuclear Marker we found that induced neurons do display neuronal features that are seen in mature neurons.
ContributorsSwinford, Sarah Joan (Author) / Neisewander, Janet (Thesis director) / Sattler, Rita (Committee member) / Nelson, Andrew (Committee member) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05