Matching Items (409)
Description
Though it is a widespread adaptation in humans and many other animals, parental care comes in a variety of forms and its subtle physiological costs, benefits, and tradeoffs related to offspring are often unknown. Thus, I studied the hydric, respiratory, thermal, and fitness dynamics of maternal egg-brooding behavior in Children's pythons (Antaresia childreni). I demonstrated that tight coiling detrimentally creates a hypoxic developmental environment that is alleviated by periodic postural adjustments. Alternatively, maternal postural adjustments detrimentally elevate rates of egg water loss relative to tight coiling. Despite ventilating postural adjustments, the developmental environment becomes increasingly hypoxic near the end of incubation, which reduces embryonic metabolism. I further demonstrated that brooding-induced hypoxia detrimentally affects offspring size, performance, locomotion, and behavior. Thus, parental care in A. childreni comes at a cost to offspring due to intra-offspring tradeoffs (i.e., those that reflect competing offspring needs, such as water balance and respiration). Next, I showed that, despite being unable to intrinsically produce body heat, A. childreni adjust egg-brooding behavior in response to shifts in nest temperature, which enhances egg temperature (e.g., reduced tight coiling during nest warming facilitated beneficial heat transfer to eggs). Last, I demonstrated that A. childreni adaptively adjust their egg-brooding behaviors due to an interaction between nest temperature and humidity. Specifically, females' behavioral response to nest warming was eliminated during low nest humidity. In combination with other studies, these results show that female pythons sense environmental temperature and humidity and utilize this information at multiple time points (i.e., during gravidity [egg bearing], at oviposition [egg laying], and during egg brooding) to enhance the developmental environment of their offspring. This research demonstrates that maternal behaviors that are simple and subtle, yet easily quantifiable, can balance several critical developmental variables (i.e., thermoregulation, water balance, and respiration).
ContributorsStahlschmidt, Zachary R (Author) / DeNardo, Dale F (Thesis advisor) / Harrison, Jon (Committee member) / McGraw, Kevin (Committee member) / Rutowski, Ronald (Committee member) / Walsberg, Glenn (Committee member) / Arizona State University (Publisher)
Created2011
Description
Nucleosomes are the basic repetitive unit of eukaryotic chromatin and are responsible for packing DNA inside the nucleus of the cell. They consist of a complex of eight histone proteins (two copies of four proteins H2A, H2B, H3 and H4) around which 147 base pairs of DNA are wrapped in ~1.67 superhelical turns. Although the nucleosomes are stable protein-DNA complexes, they undergo spontaneous conformational changes that occur in an asynchronous fashion. This conformational dynamics, defined by the "site-exposure" model, involves the DNA unwrapping from the protein core and exposing itself transiently before wrapping back. Physiologically, this allows regulatory proteins to bind to their target DNA sites during cellular processes like replication, DNA repair and transcription. Traditional biochemical assays have stablished the equilibrium constants for the accessibility to various sites along the length of the nucleosomal DNA, from its end to the middle of the dyad axis. Using fluorescence correlation spectroscopy (FCS), we have established the position dependent rewrapping rates for nucleosomes. We have also used Monte Carlo simulation methods to analyze the applicability of FRET fluctuation spectroscopy towards conformational dynamics, specifically motivated by nucleosome dynamics. Another important conformational change that is involved in cellular processes is the disassembly of nucleosome into its constituent particles. The exact pathway adopted by nucleosomes is still not clear. We used dual color fluorescence correlation spectroscopy to study the intermediates during nucleosome disassembly induced by changing ionic strength. Studying the nature of nucleosome conformational change and the kinetics is very important in understanding gene expression. The results from this thesis give a quantitative description to the basic unit of the chromatin.
ContributorsGurunathan, Kaushik (Author) / Levitus, Marcia (Thesis advisor) / Lindsay, Stuart (Committee member) / Woodbury, Neal (Committee member) / Yan, Hao (Committee member) / Arizona State University (Publisher)
Created2011
Description
Studies of animal contests often focus solely on a single static measurement of fighting ability, such as the size or the strength of the individual. However, recent studies have highlighted the importance of individual variation in the dynamic behaviors used during a fight, such as, assessment strategies, decision making, and fine motor control, as being strong predictors of the outcome of aggression. Here, I combined morphological and behavioral data to discover how these features interact during aggressing interactions in male virile crayfish, Faxonius virilis. I predicted that individual variation in behavioral skill for decision making (i.e., number of strikes thrown), would determine the outcome of contest success in addition to morphological measurements (e.g. body size, relative claw size). To evaluate this prediction, I filmed staged territorial interactions between male F. virilis and later analyzed trial behaviors (e.g. strike, pinches, and bout time) and aggressive outcomes. I found very little support for skill to predict win/loss outcome in trials. Instead, I found that larger crayfish engaged in aggression for longer compared to smaller crayfish, but that larger crayfish did not engage in a greater number of claw strikes or pinches when controlling for encounter duration. Future studies should continue to investigate the role of skill, by using finer-scale techniques such as 3D tracking software, which could track advanced measurements (e.g. speed, angle, and movement efficiency). Such studies would provide a more comprehensive understanding of the relative influence of fighting skill technique on territorial contests.
ContributorsNguyen, Phillip Huy (Author) / Angilletta, Michael (Thesis director) / McGraw, Kevin (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
This dissertation explores the lives of women who are on the Severely Mentally Ill (SMI) caseload at Maricopa County Adult Probation in Arizona (The Phoenix metro region). The project focuses on three primary issues: (1) what are the pathways to the criminal justice and mental health systems for women on the SMI caseload (2) how does discretion and expansive formal social control (both benevolent and coercive) impact the lives of these women on the SMI caseload and (3) what are the gendered aspects to successful completion of SMI probation. To answer these questions a mixed-methods research design was employed. First, in-depth semi-structured interviews were completed with 65 women on the SMI caseload. Second, these interviews were supplemented with a case file review of each participant, and field observations (encompassing roughly 100 hours) were conducted at the Maricopa County Mental Health Court. Third, analysis also included 5.5 years of quantitative intake data from the SMI caseload, exploring demographic information and risk and assessment needs scores. The biographies of the women on the SMI caseload revealed similar histories of victimization, substance abuse, and relationship difficulty that previous pathways research has noted. Additionally, mental health problems directly impacted the path to the criminal justice system for some women on the SMI caseload. Results also showed many aspects of expanded social control for women on the SMI caseload. This expanded control appeared to be gendered at times and often created double binds for women. Finally, quantitative analysis showed that some predictive factors of SMI probation completion were gendered. Policy implications and summaries of findings are discussed.
ContributorsMulvey, Philip (Author) / Decker, Scott H. (Thesis advisor) / Spohn, Cassia (Committee member) / Holtfreter, Kristy (Committee member) / Arizona State University (Publisher)
Created2013
Description
The study of non-U.S. citizens in criminal justice system outcomes has often been neglected in the sentencing literature. When citizenship is considered, there are generally no distinctions made within this group. The research fails to consider differences according to legal status, race/ethnicity, nationality and other distinctive markers that might play a role in sentencing outcomes. Using federal sentencing data collected by the United States Sentencing Commission for fiscal year 2006 through fiscal year 2008, this study examines the effect of offender citizenship status, legal status, and national origin on the likelihood of imprisonment and length of imprisonment for offenders convicted of drug offenses. The current study considers differences among foreign-born and Latino immigrant subgroups (e.g., Colombian, Cuban, Dominican, and Mexican nationals). The key findings in this dissertation include: (1) non-U.S. citizens have greater odds of imprisonment than U.S. citizens. However, non-U.S. citizen offenders receive significantly shorter prison terms relative to U.S. citizen offenders; (2) undocumented immigrants are more likely to be incarcerated compared to similarly situated authorized immigrants and U.S. citizens. However, legal status does not have an effect on sentence length; and (3) with respect to national origin, Mexican nationals are significantly more likely than Colombians to be incarcerated and are given significantly longer prison sentences than Dominican nationals. The implications of these findings and future research are addressed in the concluding chapter.
ContributorsValadez, Mercedes (Author) / Spohn, Cassia (Thesis advisor) / Wang, Xia (Committee member) / Wright, Kevin (Committee member) / Arizona State University (Publisher)
Created2013
Description
Human-induced rapid environmental change (HIREC) influences nearly all of Earth's ecosystems through processes such as urbanization. Previous studies have found that urbanization influences biodiversity patterns, often yielding an increase in the abundance of a few urban-adapted taxa at the expense of native species diversity. The western black widow spider, Latrodectus hesperus, is a medically-important pest species that often forms dense urban subpopulations (i.e., infestations) relative to the low-density subpopulations found throughout undisturbed, desert habitat. Here, I employ field and laboratory studies to examine the population ecology and stoichiometry of this urban pest to increase our understanding of the mechanisms underlying its success. The population ecology of ten black widow subpopulations spread across metropolitan Phoenix, AZ was examined during the peak breeding season (June-August). This study revealed that arthropod prey abundance, female mass and population density of females showed significant spatial variation across the ten subpopulations. Additionally, prey abundance and foraging success, measured as the number of carcasses found in webs, were a strong determinant of female mass and population density within each subpopulation. To test the mechanisms that drive black widow infestations, I used ecological stoichiometry to examine the nutrient (nitrogen and phosphorus) composition of spiders and arthropod prey from urban habitat, desert habitat and a laboratory diet regime. These studies revealed that (1) spiders are more nutrient rich than cricket prey in the field, (2) spider subpopulations exhibit significant spatial variation in their nitrogen composition, (3) nutrient composition of urban spider subpopulations does not differ significantly from Sonoran desert subpopulations, (4) laboratory-reared spiders fed a diet of only laboratory-reared crickets are more nitrogen and phosphorus limited than field-captured spiders, and (5) cannibalism by laboratory-reared spiders alleviated phosphorus limitation, but not nitrogen limitation, when compared to field-captured spiders. This work highlights the need to examine the population ecology of species relationships, such as predator-prey dynamics, to fully understand the fecundity and population growth of urban pest species. Moreover, the integration of population ecology and stoichiometry illustrates the need to address mechanisms like nutrient limitation that may explain why urban pest populations thrive and native species diversity suffers following HIREC.
ContributorsTrubl, Patricia (Author) / Johnson, James C. (Thesis advisor) / Rutowski, Ronald (Thesis advisor) / McGraw, Kevin (Committee member) / Arizona State University (Publisher)
Created2012
Description
Criminologists have directed significant theoretical and empirical attention toward the institution of marriage over the past two decades. Importantly, the momentum guiding this line of research has increased despite the fact that people are getting married far less often and much later in the life course than in any point in American history. The aim of this dissertation is to address this disconnect by focusing attention to nonmarital romantic relationships and their instability during emerging adulthood. To do so, it uses data from the Pathways to Desistance Study, a longitudinal study of 1,354 at-risk males and females who were adjudicated from the juvenile and adult systems in Phoenix and Philadelphia between 2000 and 2003. The project focuses attention to the following issues: (1) the effect of romantic dissolution on aggressive and income-based offenses; (2) the extent to which strain
egative emotionality and peer influence/exposure account for the effect of romantic dissolution on crime; and (3) the extent to which certain relationship and individual circumstances moderate the effect of romantic dissolution. The models reveal a few key findings. First, romantic dissolution is strongly related to an increase in both aggressive and income-based crime, but is more strongly related to income-based crime. Second, the effect of romantic dissolution is reduced when measures of strain
egative emotionality and peer influence/exposure measures are added to models, but the peer influence/exposure measures account for the strongest reduction. Finally, romantic dissolution does not serve as a positive life event among these at-risk youth, but its effect is exacerbated under a number of contexts (e.g. when an individual is unemployed). This study closes with a summary of these findings as well as its key limitations, and offers insight into potential policy implications and avenues of future research.
egative emotionality and peer influence/exposure account for the effect of romantic dissolution on crime; and (3) the extent to which certain relationship and individual circumstances moderate the effect of romantic dissolution. The models reveal a few key findings. First, romantic dissolution is strongly related to an increase in both aggressive and income-based crime, but is more strongly related to income-based crime. Second, the effect of romantic dissolution is reduced when measures of strain
egative emotionality and peer influence/exposure measures are added to models, but the peer influence/exposure measures account for the strongest reduction. Finally, romantic dissolution does not serve as a positive life event among these at-risk youth, but its effect is exacerbated under a number of contexts (e.g. when an individual is unemployed). This study closes with a summary of these findings as well as its key limitations, and offers insight into potential policy implications and avenues of future research.
ContributorsLarson, Matthew Joseph (Author) / Sweeten, Gary (Thesis advisor) / Piquero, Alex (Committee member) / Spohn, Cassia (Committee member) / Wallace, Danielle (Committee member) / Arizona State University (Publisher)
Created2013
Description
Healthy mitochondria are essential for cell survival. Described herein is the synthesis of a family of novel aminoquinone antioxidants designed to alleviate oxidative stress and prevent the impairment of cellular function. In addition, a library of bleomycin disaccharide analogues has also been synthesized to better probe the tumor targeting properties of bleomycin. The first study involves the synthesis of a benzoquinone natural product and analogues that closely resemble the redox core of the natural product geldanamycin. The synthesized 5-amino-3-tridecyl-1,4-benzoquinone antioxidants were tested for their ability to protect Friedreich's ataxia (FRDA) lymphocytes from induced oxidative stress. Some of the analogues synthesized conferred cytoprotection in a dose-dependent manner in FRDA lymphocytes at micromolar concentrations. The biological assays suggest that the modification of the 2-hydroxyl and N-(3-carboxypropyl) groups in the natural product can improve its antioxidant activity and significantly enhance its ability to protect mitochondrial function under conditions of oxidative stress. The second project focused on the synthesis of a library of bleomycin disaccharide-dye conjugates and monitored their cellular uptake by fluorescence microscopy. The studies reveal that the position of the carbamoyl group plays an important role in modulating the cellular uptake of the disaccharide. It also led to the discovery of novel disaccharides with improved tumor selectivity.
ContributorsMathilakathu Madathil, Manikandadas (Author) / Hecht, Sidney M. (Thesis advisor) / Rose, Seth (Committee member) / Woodbury, Neal (Committee member) / Arizona State University (Publisher)
Created2013
Description
The purpose of this project is to better understand the factors associated with, and effects of, prison visitation for children during maternal and paternal incarceration. As gatekeepers, caregivers play a pivotal role in the facilitation of parent-child prison visitation. Yet, some caregivers may be more likely to take children to visit than others. Additionally, among those children who do visit, visitation may be positive in some ways and negative in others. To advance prior work, this study (1) assesses the relationship between caregiver type and parent-child prison visitation and (2) investigates the emotional and behavioral responses of children who visit. The current research uses mixed-methods and is carried out in two phases. For Phase 1, quantitative data on 984 children collected from structured interviews with incarcerated parents (N=279 mothers; N=143 fathers) in the Arizona Department of Corrections are used to examine the relationship between caregiver type and the likelihood of parent-child prison visitation. Descriptive statistics and logistic regression analyses are conducted separately for maternal and paternal incarceration. Phase 2 draws on caregivers' accounts of 40 children who visit their parent in prison to assess children's emotional and behavioral reactions to visitation. Data are coded to identify positive and negative responses, "visitation paradox" indicators, prior life circumstances and child age. Thematic content analyses are conducted to capture major themes. Analyses from Phase 1 confirm a significant relationship between caregiver type and mother-child and father-child visitation. Other factors that affected the likelihood of parental visitation included child situational factors, parent stressors, institutional barriers and child demographics, although these effects differed depending upon which parent was in prison. Results from Phase 2 revealed overwhelmingly negative responses among children to parental prison visitation. Key themes that accounted for child reactions included institutional context and parental attachment. This research adds to the collateral consequences of incarceration literature by providing greater insight into the imprisonment experience for vulnerable families. Further, these results have direct implications for correctional policy and practice pertaining to the manner and regulation of prison visits and also inform reentry efforts through a family-centric approach.
ContributorsTasca, Melinda (Author) / Rodriguez, Nancy (Thesis advisor) / Spohn, Cassia (Committee member) / Zatz, Marjorie S (Committee member) / Arizona State University (Publisher)
Created2014
Description
The purpose of this preliminary study is to determine if sentencing disparities exist between male and female teachers who have been convicted of sexual misconduct with a student in Maricopa County, Arizona over a ten-year period. The hypothesis is that male teachers convicted of sexual misconduct with a student will receive harsher punishment than their female counterparts. In addition, this research will analyze the sentencing decisions of Arizona judges and prosecutors through plea-bargaining when compared with the presumptive sentence set by the Arizona Legislature. Issues that will be addressed include: a brief review of gender disparities in sentencing, sex offender sentencing, Arizona's rules of criminal procedure, and a review of the Arizona Revised Statutes pertaining to sexual crimes as well as the Arizona Supreme Court sentencing guidelines. The data set consists of fifteen different Maricopa County teachers who committed a sexual offense against a student and were convicted of that offense from February 2000 through September 2009. According to the results of this study, male teachers do receive harsher penalties than their female counterparts within Maricopa County.
ContributorsSimmon, Christopher (Author) / Holtfreter, Kristy (Thesis advisor) / Wright, Kevin (Committee member) / Spohn, Cassia (Committee member) / Arizona State University (Publisher)
Created2012