<p> Although school dropout rate remains a significant social and economic concern to our nation and has generated considerable research, little attention by scholars has examined the phenomena of re-engagement in effective school context and its developmental influences on at-risk students expectancy for success and task-value towards graduation. Given the multifaceted interactions of school context and the complex developmental needs of at-risk students, there were dual purposes for this three-phase, two-method qualitative study that addressed the literature concerns.</p><p> The first purpose was to explore and identify policies, programs, and practices perceived as being most effective in re-engaging at-risk students behaviorally, emotionally, and cognitively, at ten Model Continuation High Schools in California. Phases one and two collected data on the Model Continuation High Schools (MCHS) to address this purpose.</p><p> In phase one, an inductive document review of the ten MCHS applications including four statement letters was conducted and results identified eleven policies, ten programs, and eleven practices that were effective in re-engaging at-risk students behaviorally, emotionally, and cognitively. In phase two, the phenomenological ten-step analysis of semi-structured administrator interviews revealed eight re-engaging implementation strategies perceived to be effective with at-risk students.</p><p> The second purpose was to build upon Eccles' Expectancy-Value Theoretical Framework by gaining insight on effective school context that supported at-risk students' developmentally appropriate expectancy for success and task-value beliefs towards graduation. Phase three conducted a deductive content analysis of eight theoretical based components on the combine data collected in phases one and two to address this second purpose. Results revealed that principles of Eccles&rsquo; Expectancy-Value Model were evident in all identified policies, programs, and practices of the ten MCHS.</p><p> Model Continuation High Schools are exemplary sites with effective school context that have much to share with other continuation high schools looking for successful re-engaging approaches for at-risk students. The research provided results suggesting that MCHS had significant policies, programs, practices and implementation strategies that transform disengaged at-risk students into graduates by developing students' expectancy for success belief and task-value belief towards graduation. Implications for policy, practice, and future research are discussed.</p>

<p> Na⁺/Ca²⁺ exchangers are low affinity/high capacity transporters that mediate Ca²⁺ extrusion by coupling Ca²⁺ efflux to the influx of Na⁺ ions. Their primary function is to maintain Ca²⁺ homeostasis in cells of all organisms and they play a particularly important role in excitable cells that experience transient Ca²⁺ fluxes. While their functions have been studied extensively in muscle cells, much is still unknown about their contributions to the nervous system. Data suggests that Na⁺/Ca²⁺ exchangers play a key role in neuronal processes such as memory formation, learning, oligodendrocyte differentiation and axon guidance. They are also implicated in pathologies such as Alzheimer&rsquo;s Disease, Parkinson&rsquo;s Disease, Multiple Sclerosis and Epilepsy. While they are implicated in critical neuronal processes, a clear understanding of their mechanism remains unknown. This dissertation examines the role of Na⁺/Ca²⁺ exchangers in the invertebrate model organism <i>Caenorhabditis elegans </i>. There are ten identified Na⁺/Ca²⁺ exchanger genes in <i>C. elegans</i> (labeled <i>ncx-1</i> to <i>ncx</i>-10). Data presented here is the first comprehensive description of their genetics and function in <i>C. elegans</i>. The expression pattern of all 10 Na⁺/Ca²⁺ exchanger genes is described and their phylogeny is examined comparatively across humans and flies. Analysis of <i>ncx-2</i> and <i>ncx-8</i> mutants shows important roles for Na⁺/Ca²⁺ exchanger genes in egg-laying, lipid storage and longevity, suggesting a role in diverse biological functions for Na⁺/Ca²⁺ exchangers in <i>C. elegans</i>. The function of an NCLX type Na⁺/Ca²⁺ exchanger NCX-9 is also detailed comprehensively. Analysis of <i> ncx-9</i> mutants shows that NCX-9 is required for asymmetrical axon guidance choices made by the DD and VD GABAergic motor neuron circuit. Pathway analysis shows that NCX-9 regulates asymmetric circuit patterning through RAC-dependent UNC-6/Netrin signaling and LON-2/Glypican Heparan Sulfate signaling. <i> In vitro</i> analysis of NCX-9 physiology in HEK cells shows that NCX-9 is a mitochondrial Na⁺/Ca²⁺ exchanger, similar to NCLX, which is its homolog in humans.</p>

<p>Abstract</p><p>During embryonic development many structures crucial for breathing and eating arise from the pharyngeal and anterior foregut epithelium (FGE), which contains the oral ectoderm and the foregut endoderm. Proper differentiation and signaling within and from this epithelial tissue is necessary for the development of the mandible, the esophagus, and the trachea. Many birth defects occur in these structures that greatly disrupt the ability of affected infants to breathe and eat. This dissertation investigates the importance of the pharyngeal and anterior FGE in mandible and foregut development. </p><p>The most rostral portion of the pharyngeal epithelium contributes to the development of the mandible. At embryonic day 10.5 the mandible is a bud structure, composed of neural crest-derived mesenchyme and core mesoderm surrounded by pharyngeal epithelium. The mesenchyme needs to receive Hedgehog signaling for mandible development, but the epithelial tissue that signals to the mesenchyme has not been identified in mammals. Data presented in Chapter 2 show that Sonic Hedgehog is necessary at two distinct stages of mandible development by using a tissue specific genetic ablation to remove Sonic Hedgehog from the pharyngeal endoderm. First, we show that Sonic Hedgehog promotes cell survival prior to cartilage differentiation through immunostaining for Caspase-9, an apoptosis marker. Second, a rescue of early cell death with the p53 inhibitor pifithrin-&#945; shows that Sonic Hedgehog is necessary for cartilage condensation and differentiation later in development. Without cartilage differentiation the mandible is unable to elongate properly and hypoplasia occurs.</p><p>Caudal to the pharyngeal epithelium is the anterior FGE, which develops into the larynx, esophagus and trachea. The anterior FGE is a single endodermal tube at E9.5 and by E11.5 compartmentalizes into two distinct tubes: the esophagus and trachea. While the signaling pathways involved in proper compartmentalization of the foregut are well studied, nothing is known about the cellular behaviors that drive this complex event. One important event during foregut compartmentalization is the establishment of dorso-ventral patterning, which is necessary for separation to occur. To elucidate the importance of dorso-ventral patterning, we take advantage of two genetic mouse models with disrupted patterning, an activation of and a removal of &#946;-catenin in the ventral foregut endoderm. Data presented in Chapter 3 show that &#946;-catenin is important for epithelial pseudostratification and the establishment of a region of double-positive cells at the dorso-ventral midline through close examination of epithelial morphogenesis at E10.5 prior to compartmentalization. This data has established two mouse models for studying changes in epithelial morphology during foregut compartmentalization. In total, this body of work details how signals originating in the pharyngeal and anterior foregut epithelium regulate both mesenchymal and epithelial behaviors during mandible and foregut development.</p> / Dissertation

No description available.

<p> Sudden infant death syndrome (SIDS) occurs when a sleeping infant experiences a challenge to cardiorespiratory homeostasis which it fails to overcome. Analyses of brain tissue from SIDS cases from around the world consistently show abnormalities in the brainstem serotonin systems. These include increased numbers of neurons that test positive for serotonergic markers, but have an immature phenotype, reduced brain tissue serotonin concentrations and decreased serotonin receptor binding in projection sites important to cardiorespiratory homeostasis, including the nucleus of the solitary tract (NTS). The NTS is of particular interest in the pathophysiology of SIDS because it is the integration center for afferent projections involved in eliciting several apnea-inducing reflexes long suspected of contributing to SIDS. The laryngeal chemoreflex (LCR), an airway protective reflex which is initiated when water, acidic solutions, or low [Cl-] solutions activate chemoreceptors in the larynx, is one such reflex. In infants, inhibitory reflex responses to hypoxia (apnea, bradycardia, decreased metabolic activity) that are adaptive for a fetal environment that precludes the possibility of the fetus acquiring more oxygen by increasing breathing, persist for some time into the postnatal period. Therefore, hypoxia resulting from apnea caused by the LCR can result in a cataclysmic downward spiral of apnea, followed by increasing hypoxic inhibition of respiration, which ultimately leads to SIDS. We hypothesized that increasing serotonin signaling in the brainstems of rat pups would shorten the apnea and respiratory disruption caused by eliciting the LCR. We have shown that both intracisternal injections of serotonin, and microinjections of serotonin into the caudal NTS, dramatically shorten the LCR. This effect is also seen after microinjection into the NTS of the 5-HT3 specific agonist CPG. Chemical stimulation by microinjection of AMPA of neurons in the raphe obscurus, some of which send serotonergic projections to the NTS, also shortens the LCR, but this effect is blocked by prior injection of a 5-HT3 antagonist in the NTS. Our work suggests that serotonergic projections to the NTS from the caudal raphe may play an important role in limiting the duration of apnea following inhibitory reflexes like the LCR and in the subsequent restoration of eupnea.</p>

<p> The current study investigated the relationships between mother-child, father-child, parent-cohesion, and children&rsquo;s self-concept. Participants included 30 early adolescents (ages 10 to 15 years) from intact family arrangements. Children completed a modified version of the Family System Test (FAST) to assess levels of parent-child cohesion. The Piers-Harris 2 was used to evaluate dimensions of self-concept. A series of sequential multiple regressions were performed to determine the relationships parent-child cohesion variables had with self-concept constructs, after controlling for the children&rsquo;s sex and typical grades. Only father-child cohesion scores significantly related to adolescents&rsquo; ratings on specific facets of self-concept (i.e., Behavioral Adjustment, Intellectual and School Status), suggesting that children who report feeling closer to their fathers also endorsed items reflecting less problematic behavior and more intellectual/academic competence. Findings suggest mothers and fathers contribute differentially to adolescents&rsquo; self-concept. Implications for parental education and ensuring children have a caring, male role model are discussed. Limitations to the study included issues with sample size, generalizability, and data collection.</p>

It has been indicated through research and by personal testimony that although some barriers for inclusion for those with special needs have been broken down since the enactment of the Americans with Disabilities Act of 1990, one of the most significant barriers still remains - negative and often subtle attitudes. Positive attitudes toward individuals with special needs have been shown to facilitate inclusion while negative attitudes hinder inclusion. Since the ADA law exempted churches from the mandates for inclusion, many have found participating in churches a significant challenge. The purpose of this study was to explore the attitude measurement score of senior pastors as it relates to awareness of special needs populations, types of special education ministries in the churches, previous life experiences with persons with developmental disabilities, and the pastor's training through formal and informal courses of instruction related to developmental disabilities. The research explored potential factors which shape pastoral attitudes and result in either barriers or facilitators to intentional special needs ministries. Data was collected through an online survey format and the results were used in a statistical analysis to facilitate the answering of the research questions. The sample population for the research included the 1296 senior pastors of Southern Baptist churches in South Carolina who have published church and/or personal email addresses in the South Carolina Baptist Annual Report 2008. Through statistical analysis of the survey results, precedent literature review concepts concerning the value oflife experiences with individuals with developmental disabilities can have a positive impact on positive attitudes. The pastors overall had positive attitudes toward individuals with developmental disabilities, but most significantly in the realm of the behavioral domain. Strong statistically significant correlations could not be drawn between having a positive attitude toward individuals with special needs and special needs ministry among the pastor's surveys. There were definite trends which support the important roles of experience and education being made available to pastors in order to potentially bring positive changes concerning inclusion in local churches. Keywords: attitude measurement, special needs ministry, pastoral attitudes, individuals with developmental disabilities, church special education ministry

<p> To gain an understanding of children&rsquo;s social milieu, this study explored international children&rsquo;s phenomenology about their social networks, stressors, and supports using the ecomap, a graphic tool that maps children&rsquo;s social relationships and their appraisals of them. Specifically, it addressed the following two research questions using archival ecomap data collected from 816 school-aged children (ages four &ndash; 19 years) from 14 cities in 12 countries (Brazil &ndash; Manaus, Estonia &ndash; Tallinn, Greece &ndash; Athens, India &ndash; Mumbai, Italy &ndash; Padua, Mexico &ndash; Xalapa, Romania &ndash; Bucharest, Russia &ndash; Samara, Slovak Republic &ndash; Ko&scaron;ice, Sri Lanka &ndash; Negombo, Tanzania &ndash; Arusha, and the United States &ndash; Boston, Massachusetts; Mayag&uuml;ez, Puerto Rico; New Orleans, Louisiana): (a) What are the characteristics of international children&rsquo;s social networks, and what cross-cultural patterns exist; and (b) Who and what do children consider their social supports and social stressors, and what cross-cultural patterns emerge? The nature of the ecomap drawings and their associated narratives allowed for a concurrent mixed methods approach to be used to identify cross-cultural phenomenological patterns about the structures (network size, embeddedness, and network composition), functions (stressor and support types), and evaluations (relationship appraisals) of children&rsquo;s social worlds. Considerable diversity was found in the data, but a number of notable cross-site, cross-gender, and cross-age patterns were identified. In general, children in this sample reported a trimmed mean network size of 7.87 (<i>SD</i> = 3.61), with middle school students reporting the largest (<i>M</i> = 8.78). Embeddedness, measured as the balance of perceived stress and supports (Nastasi &amp; Borja, 2015; Summerville, 2013), also was generally positive, suggesting that children generally perceive themselves to be connected to their social networks. Most commonly reported members included home parent/caregivers, friends/peers, extended family members, and siblings; and across grade levels, sites, and gender, network members were generally appraised positively. When asked about the ways that network members support or trigger distress, youth in this sample described over 50 stress and support themes, most of which related to interpersonal relationships and interactions. The results of the current study not only contributes to the literature on children&rsquo;s stressors and supports, but also build on Nastasi and colleagues&rsquo; <i>Promoting Psychological Well-Being Globally</i> project (PPWBG; Nastasi &amp; Borja, 2015), whose international team collected the ecomap data to understand children&rsquo;s well-being and the culturally- and developmentally-unique factors that influence them.</p>

<p>We propose to establish a free-living, fresh water flatworm species from the superphylum Lophotrochozoa, Schmidtea mediterranea, to be a genetic model system. S. mediterranea has been vigorously investigated as a powerful system to study adult stem cells and organ regeneration. Its sexual biotype has also been established as a system to understand the inductive mode of germ cell formation that is broadly shared by a lot of species including mammals. However, little is known about the sexual reproduction and genetics in this organism, which limited the availability of genetic approaches. As the sexual planarian is found scattered but with relative abundance in Sardinia, its natural history also presents us the opportunity to study inbreeding?s effect on genetic variability and species survival. Therefore, to study sexual reproduction and genetic inheritance in S. mediterranea will provide us unique opportunities to understand whole body regeneration, inductive germ cell formation, and inbreeding. In this dissertation, progresses in the establishment of the foundation for genetic analysis in S. mediterranea were presented. Though a simultaneous hermaphrodite, the anatomical and genotyping studies concluded that S. mediterranea cross-fertilize. One worm (line S2) was inbred for 10 generations by taking one progeny from each generation and crossing this individual to its regenerated clones. Whole genome sequencing of four different generations in this inbreeding pedigree revealed ~300Mb of the genome maintained their heterozygosity. Further sequencing analysis of the male and female gametes found these regions had low recombination rates, and maintained as two haplotypes (J-/V- haplotypes). Failure of gametes of the same haplotype to form progeny is unlikely due to embryonic lethality as the arrested embryos were significantly less than hatchlings. Additional analysis of two lines (D5D/D5I) with 90% of these regions homozygous as the J-haplotype suggested failure in fertilization between gametes of the same haplotype. Hence, we propose that haplotype incompatibility is the driving mechanisms to maintain genome heterozygosity in the planarian genome. Understanding of the genetic strategies in S. mediterranea will help the development of genetic approaches to study regeneration and germ cell specification. Our findings also suggest S. mediterranea can be a model system to study the evolution of sex and gamete incompatibility.

No description available.