Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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2005 - 200912010 - 20141

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    Insertion and Evolution of an Endogenous Retrovirus into KIT is Responsible for Multiple Phenotypes at the White Locus in the Domestic Cat
    (2014) Wallace, Andrea Brynne; Menotti-Raymond, Marilyn; Mount, Stephen M; Biology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The Dominant White locus (W) in the domestic cat demonstrates pleiotropic effects exhibiting complete penetrance for absence of coat pigmentation and incomplete penetrance for deafness and iris hypopigmentation. I preformed linkage analysis using a pedigree segregating White to identify KIT (Chr. B1), as the feline W locus. Segregation and sequence analysis of the KIT gene in two pedigrees (P1 and P2) revealed the remarkable retrotransposition and evolution of a feline endogenous retrovirus (FERV1) as responsible for two distinct phenotypes of the W locus, Dominant White, and White Spotting. The retrotransposition interrupts a DNase I hypersensitive site in KIT intron 1 that was previously demonstrated to regulate temporal and tissue specific expression of KIT in mice. A large population-genetic survey of cats (n=269), supports our findings and demonstrates statistical significance of the FERV1 LTR and full-length element with Dominant White (p < 0.0001) and White Spotting (p< 0.0001), respectively.
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    Social and Emotional Functioning of Children with Cochlear Implants
    (2005-04-18) Schorr, Efrat; Fox, Nathan A; Human Development; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Studies of infants and children have demonstrated the importance of sensory processing in facilitating social and emotional development. Children who are deaf are deprived of the information typically provided by the auditory modality that is necessary to the development of basic social and emotional skills, which serve as the foundation upon which complex social and emotional constructs are built. Children with cochlear implants experience extended periods of total auditory deprivation during early childhood, followed by the introduction of auditory stimulation. Thirty-nine children with cochlear implants, aged five through fourteen, as well as an age and sex matched group of normal hearing peers, participated in assessment of the integrated perception of multimodal stimuli, processing of facial and vocal expressions of emotion, and emotion understanding skills. These dimensions of basic social and emotional functioning are vulnerable to the effects of atypical early experience. The age at which children received their cochlear implant and the length of time that they have used the cochlear implant were hypothesized to predict performance on the assessments. Results showed that the age at implant predicted performance on the McGurk fusion task, which requires the integration of multimodal sensory stimuli. Specifically, children who received their cochlear implant prior to age 30 months accurately identified the incongruent auditory-visual stimuli, whereas children who received their cochlear implant after 30 months of age did not. Age at implant and duration of implant use did not predict performance on the other experimental tasks. Comparison of groups revealed that performance of children with cochlear implants did not differ from children with normal hearing in a facial emotion identification task and in 2 components of emotion understanding: receptive identification of facial expressions and affective-perspective taking. Children with cochlear implants demonstrated poorer performance than children with normal hearing in tasks requiring free labeling of facial expressions of emotion, and vocal emotion identification. This research suggests sensitive periods in multimodal sensory integration. The present study provides understanding of the social and emotional influences of early experience with the auditory system on children with cochlear implants.