This study investigated the conditions under which communicative interactions were facilitated in hearing-impaired children and their caregivers as compared to normally hearing children and their caregivers. Participants were six normally hearing children and five hearing-impaired children, and their caregivers. Each interactant's communicative behaviors were coded for the intentions conveyed, discourse turn types, and verbal or nonverbal modalities of expression. Patterns emerged regarding caregiver communicative behaviors that facilitated children's participation in ongoing conversations. Caregiver behaviors most likely to be followed by on-topic responses from normally hearing and hearing-impaired children included caregiver requests, messages expressed through simultaneous verbal and nonverbal means, and turns that extended topics of conversations. Hearing-impaired children tended to produce more partially inadequate on-topic responses to their caregivers' turns than did the normally hearing children. Results are discussed with regard to clinical implications for the improvement or intervention with hearing-impaired children.

This doctoral thesis reports a series of studies aimed at exploring the control of body equilibrium during perturbations of the bipedal stance in healthy humans, and its modifications by aging and Parkinson's disease (PD). With the use of two unique experimental paradigms, we investigated reflex interactions during forward whole head-and-body tilts (WHBT) in healthy young and elderly subjects, and PD patients. We discovered that the excitability of extensor muscle responses to the stimulation of flexion reflex (FR) afferents was enhanced during WHBTs in young normal subjects. Such a functional output suggested that the specific needs of balance maintenance could have governed the reflex interaction during WHBTs rather than limb withdrawal. / A significantly smaller proportion of elderly than young subjects showed an increase or a decrease of the FR in their ipsilateral tibialis anterior muscle (iTA) during WHBT. This indicated a lack of FR modifiability during dynamic perturbations of standing balance with aging. Such a change in reflex interaction could originate from a defect in the sensorimotor integration needed for the proper control of forward WHBT. / PD patients were first characterized by a large increase in the excitability of their muscle responses to forward WHBT, which was accompanied by a much smaller increase in soleus H-reflex excitability during similar WHBTs. Second, they manifested a reduced FR modifiability during WHBT in comparison with age-matched normal subjects. Our findings suggest that PD might involve a specific difficulty to generate appropriate output from the interaction between flexor and extensor muscle responses. We hypothesise that an abnormal control of spinal interneurons in PD could be responsible for the tilting disorder and altered reflex interactions observed in these patients.

The scientific aim of computational neuroanatomy using magnetic resonance imaging (MRI) is to quantify inter- and intra-subject morphological variabilities. A unified statistical framework for analyzing temporally varying brain morphology is presented. Based on the mathematical framework of differential geometry, the deformation of the brain is modeled and key morphological descriptors such as length, area, volume dilatation and curvature change are computed. To increase the signal-to-noise ratio, Gaussian kernel smoothing is applied to 3D images. For 2D curved cortical surface, diffusion smoothing, which generalizes Gaussian kernel smoothing, has been developed. Afterwards, statistical inference is based on the excursion probability of random fields defined on manifolds. / This method has been applied in localizing the regions of brain tissue growth and loss in a group of 28 normal children and adolescents. It is shown that children's brains change dramatically in localized areas even after age 12.

This study was designed to compare the behavioral pain responses of 2-month-old Canadian-born Chinese babies receiving a routine immunization to those of Caucasian infants in similar situations. Two groups of 26 infants were obtained through convenience from a pediatric clinic held by a Chinese pediatrician at the Chinese Hospital and a suburban pediatric practice of a large Canadian city. Facial expression using the Neonatal Facial Coding System (Grunau & Craig, 1987) and cry using the Fast Fourier Transform were measured during 30 seconds following the insertion of the needle. Acculturation in Chinese mothers, infant temperament, circadian rhythm, were assessed. Multivariate analysis of variance revealed significant differences in pain response between these two groups with the Chinese babies showing greater response. No significant effect of temperament, circadian rhythm, and gender was identified. This supports the presence of differences in pain response in relation to culture/race by at least 2 months of age.

The locomotor behavior of adult rats (n = 48) at different age periods was determined on five inclined plexiglass runways of different widths (24, 18, 12, 6 and 3 mm). Differences in the number (old middle-age $>$ young) were observed between the three age groups. For a subset of animals (n = 17), age-related changes were examined in the organization of the morphological properties of horseradish peroxidase (HRP)-labelled motoneurons in a representative hindlimb motoneuron pool. Data suggests that the loss of large motoneurons and soma atrophy play a role (p $<$ 0.01) in the organization of the medial gastrocnemius (MG) motoneuron pool in aged animals. The relationship between the composite motor performance score and the number of MG alpha motoneurons for individual animals reflected the continuum from young to old.

<p> In the United States, there are 507 amputations each day, a number expected to grow with the increases in obesity and diabetes. This study investigated the lived experience of yoga for amputees. The researcher studied the phenomena of amputees doing yoga&mdash;<i>ampyogis</i>&mdash;for the first time, what the amputees learned about their soma through yoga on the mat, and the significance of transference of their learning from the yoga mat to their lives off the mat. Existing literature defines rehabilitative practices for amputees to take care of daily life necessities, such as learning to walk with a prosthetic, as well as the impact of yoga on multiple populations, such as cancer survivors, those with multiple sclerosis, trauma victims, and children with attention deficit disorders. There is a current body of literature on somatic practices, moving the body with the intention to produce a certain outcome in the soma. This was a qualitative study informed by phenomenology. The researcher designed semistructured interviews to follow the participants' narratives about events that led to amputation, their postamputation felt sense of self, and the impact of yoga on shifts in their felt sense of self. Findings indicate themes of organizing principles for the ampyogis that reflect the embodied motivation to enact change on, through, and with their bodies. Themes observed included demonstrated increased capacity among ampyogis to self-accept, to appreciate their bodies and minds, and to self-generate their choices and decision-making. Findings suggest that participants shifted their somas; and increased capacity for self-accountability regarding somatic choices from, for example, feeling depressed and frustrated, to feeling more alive, balanced, and graceful. Participants reported increased capacity for self-confidence, self-appreciation, and self-accountability. This research adds to literature on yoga as a rehabilitative practice for amputees. It also adds to the body of literature on somatics and shifting the soma through intention and practice. Additionally, this study demonstrates that somatics in action creates change in the soma.</p>

<p> Understanding the biophysical processes underlying biological and biotechnological processes is a prerequisite for therapeutic treatments and technological innovation. With the exponential growth of computational processing speed, experimental findings in these fields have been complemented by dynamic simulations of developmental signaling and genetic interactions. Models provide means to evaluate "emergent" properties of systems sometimes inaccessible by reductionist approaches, making them test beds for biological inference and technological refinement.</p><p> The complexity and interconnectedness of biological processes pose special challenges to modelers; biological models typically possess a large number of unknown parameters relative to their counterparts in other physical sciences. Estimating these parameter values requires iterative testing of parameter values to find values that produce low error between model and data. This is a task whose length grows exponentially with the number of unknown parameters. Many biological systems require spatial representation <i>(i.e.,</i> they are not well-mixed systems and change over space and time). Adding spatial dimensions complicates parameter estimation by increasing computational time for each model evaluation. Defining error for model-data comparison is also complicated on spatial domains. Different metrics compare different features of data and simulation, and the desired features are dependent on the underlying research question.</p><p> This dissertation documents the modeling, parameter estimation, and simulation of two spatiotemporal modeling studies. Each study addresses an unanswered research question in the respective experimental system. The former is a 3D model of a nanoscale amperometric glucose biosensor; the model was used to optimize the sensor's design for improved sensitivity to glucose. The latter is a 3D model of the developmental gap gene system that helps establish the bodyplan of <i>Drosophila melanogaster;</i> I wished to determine if the embryo's geometry alone was capable of accounting for observed spatial distributions of gap gene products and to infer feasible genetic regulatory networks (GRNs) via parameter estimation of the GRN interaction terms. Simulation of the biosensor successfully predicted an optimal electrode density on the biosensor surface, allowing us to fabricate improved biosensors. Simulation of the gap gene system on 1D and 3D embryonic demonstrated that geometric effects were insufficient to produce observed distributions when simulated with previously reported GRNs. Noting the effects of the error definition on the outcome of parameter estimation, I conclude with a characterization of assorted error definitions (objective functions), describe data characteristics to which they are sensitive, and end with a suggested procedure for objective function selection. Choice of objective function is important in parameter estimation of spatiotemporal system models in varied biological and biotechnological disciplines.</p>

<p> In the past five years, Single Molecule Real Time (SMRT) sequencing technology has been found to be a reliable indicator of certain epigenetic modifications in bacterial genomes. The genome of the model organism <i>Saccharomyces cerevisiae</i> has long been thought to be free of DNA level modification, but literature surrounding this subject is conflicting. Additionally, the mitochondria of <i>S. cerevisiae</i> control the transition between three distinct chronological life phases &ndash; exponential, postdiauxic, and stationary - as defined by their main metabolic processes. This study attempted to identify base modifications to mtDNA using PacBio sequencing while additionally establishing gene expression changes as a result of altered mitochondrial metabolic capabilities. PacBio results showed intriguing results but statistical analysis proved experimentation with improved protocols were necessary. Multiple genes with unknown or uncharacterized function were also shown to have significant differential expression between metabolic life phases.</p>

<p> Ring canals are made from arrested cleavage furrows, and provide direct cytoplasmic connections among sibling cells. They are well documented for their participation in Drosophila oogenesis, but little is known about their role in several somatic tissues in which they are also found. Using a variety of genetic tools in live and fixed tissue, I demonstrate that the &sim;250 nm diameter somatic ring canals permit rapid intercellular exchange through somatic ring canals by diffusion. Additionally, intercellular diffusion of protein was observed between cells with highly disparate levels of mRNA transcript, suggesting a possible role for ring canals in smoothing gene expression within a tissue. I also used a novel combination of markers to evaluate the extent of protein movement within mitotic clones and across clone boundaries in ovarian follicle cells and imaginal discs, providing evidence of robust movement of GFP between the two sides of mitotic clones and frequently into non-recombined cells. These data suggest that, depending on the experimental setup and proteins of interest, inter-clonal diffusion of protein may alter the interpretation of clonal data in follicle cells. Our work illustrates the lack of cytoplasmic autonomy in these tissues and suggests a role for somatic ring canals in promoting homogeneous protein expression within the tissue.</p>

<p> Refractive development has been shown to be influenced by optical defocus in the eye and the interpretation of this signal appears to be localized in the retina. Optical defocus is not uniform across the retina and has been suggested as a potential cause of myopia development. Specifically hyperopic focus, i.e. focusing light behind the retina, may signal the eye to elongate, causing myopia. This non-uniform hyperopic signal appears to be due to the retinal shape. Ultimately, these signals are detected by the retina in an as yet undetermined manner. The purpose of this thesis is to examine the retinal profile using a novel method developed at Indiana University and then to examine retinal structural changes across the retina associated with myopia. </p><p> Myopes exhibited more prolate retinas than hyperopes/emmetropes using the SD OCT. Using the SD OCT, this profile difference was detectable starting at 5 degrees from the fovea, which was closer than previously reported in the literature. These results agreed significantly with results found from peripheral refraction and peripheral axial length at 10 degrees. Overall, the total retina was thinner for myopes than hyperopes/emmetropes. It was also statistically significantly thinner for the Outer Nuclear Layer (ONL), Inner Nuclear Layer (INL) and Outer Plexiform Layer (OPL) but not for other retinal layers such as the Ganglion Layer. Thinning generally occurred outside of 5 degrees. </p><p> The SD OCT method provided a nearly 10 fold increase in sensitivity which allowed for detection of profile changes closer to the fovea. The location of the retinal changes may be interesting as the layers that showed significant differences in thickness are also layers that contain cells believed to be associated with refractive development (amacrine, bipolar, and photoreceptor cells.) The reason for the retinal changes cannot be determined with this study, but possible theories include stretch due to axial elongation, neural remodeling due to blur, and/or direct influence on refractive development due to neural cell densities.</p>