No description available.

The name retinitis pigmentosa defines a group of commonly inherited visual disorders, characterised by a progressive loss of vision. The disorder may be inherited in an autosomal dominant, recessive or X-linked recessive manner. Recently, three genes responsible for the autosomal dominant form have been identified: rhodopsin, RDS and ROM-1 on chromosomes 3,6 and 8 respectively. In this project, a panel of Scottish patients with a range of retinal degenerations including typical retinitis pigmentosa, Bardet-Biedl syndrome, Stagardts disease and cone rod dystrophy were screened for the presence of mutations in the rhodopsin and RDS genes using SSCP analysis, followed by direct sequencing to characterise the mutation. Four mutations within the rhodopsin gene and one in the RDS gene were detected and are likely to account for the phenotype in these individuals. Two polymorphisms, unrelated to the disease were also detected. Two of the four rhodopsin mutations and the RDS mutation change an amino acid residue in the corresponding proteins, whilst the third rhodopsin mutation alters the conserved splice site sequence in an intron. The effect of these mutations on the proteins is yet to be realised, but it is possible that they lead to the formation of a protein with impaired function, which in turn alters the biochemical or structural integrity of the rod cell and results in cell death. The fourth rhodopsin mutation occurs in the 3' untranslated region of the gene, but it is unknown whether this has any effect on the transcript or the protein. From the results of this study it is clear that mutations in the rhodopsin and RDS genes are a cause of retinitis pigmentosa, and also that SSCP analysis is an efficient mutation detection method.

Prior to the implementation of FAS 142 in 2002, goodwill was amortized annually. Now, companies with goodwill on their books must test it annually for impairment. This paper examines the effectiveness of goodwill amortization and impairment of goodwill both before and after the adoption of FAS 142 by analyzing their effect on abnormal stock returns. My results regarding the effect of goodwill amortization on stock returns are inconsistent, suggesting that goodwill amortization is not useful in determining the value of a company. My results also suggest that the stock market anticipates goodwill impairments before they are announced.

More than 60% of the adult population in the United States is overweight, and obesity has reached epidemic proportions in this country. Childhood obesity has more than doubled since 1990, and the health consequences are reflected in the rising cost of health care. There has also been a significant drop in physical activity across the country and physical education is no longer required in middle schools. The lack of physical activity and issues of weight can compromise the ability of the individual who is blind or visually impaired to maneuver through the environment safely and efficiently. The purpose of this study was to examine the perceptions of itinerant teachers of students with visual impairments about the importance of physical activity for their students with visual impairments and its effect on academic success and social relationship.Data was gathered from 175 teachers of students with visual impairments concerning their perceptions regarding the importance of physical activity and obesity and their relationship with academic success and social relationships. The teachers indicated that physical activity for their students is very important. They described a multitude of barriers that account for a lack of involvement in the general physical education classes in which they were enrolled.Teachers reported on their own personal physical activity levels in relationship to the importance they placed on their students' need to be active. The teachers did not indicate that being overweight was a particular issue with their visually impaired students, but they acknowledged that being overweight and a lack of physical activity create additional barriers for academic success and appropriate social relationships.The teachers also reported that the same barriers in physical education classes and access to recreation activities in the community that have been listed in past research studies were still in existence, and these barriers were also part of their dilemma in creating positive physical activity experiences for their students who are visually impaired. This study validated the necessity of further research to find the effective intervention strategies and programs to increase physical activity of students with visual impairments.

This study used survey methodology to investigate the experience of acquiring assistive technology, from learning about products, to purchasing and paying for them, to evaluating how well they perform. It examined both the challenges faced and the factors that may help people acquire products. The participants were 251 adults with vision and hearing impairments, recruited from across Canada. The results revealed that the high cost of products and lack of funding for assistive technology were the main barriers faced by respondents. Intermediaries, such as community organizations and health care providers, were found to be important facilitators of access to assistive technology. Financial support to cover product costs increased respondents’ access to higher cost items. While the majority of respondents were quite or very satisfied with their products, hearing product consumers were less satisfied than vision product consumers, yet were likely to have paid more for their products.

No description available.

Digital subscriber line (DSL) technology is used to provide high speed Internet access and, more recently, video services over twisted pair lines. Telephone lines have impairments that hinder DSL transmission, and some examples are coils and bridge taps that were introduced to aid voice telephony. Other faults are caused by physical damage that results in open circuits, short circuits or water in the line. Telephone companies have to locate and repair these faults to enable high-speed data services. It is also useful to qualify lines for future DSL service so that a new customer can be promptly informed whether high-speed service can be supplied. <p>This thesis proposes a novel technique called Wideband frequency domain reflectometry (W-FDR) to accurately locate impairments in telephone lines and estimate the reflection magnitude caused by faults. The measurement produces a result similar to the well-known time domain reflectometer (TDR), however, digital signal processing techniques are now applied to provide enhanced resolution and range. In addition to magnitude, the new technique is able to measure reflection angle which can help to determine the nature of the fault (wire in the cable, broken wires, etc). <p>The measurement technique consists of energizing the line with a sinusoid that increases from 50 kHz to 1300 kHz in discrete frequency steps after coherent detection. The amplitude of the reflected signal is recorded as a function of frequency for 2500 equally spaced frequencies. The Fourier transform and some signal processing are then used to estimate the complex reflection coefficient location of the faults in the telephone line. Lines with up to 4 reflection points have been accurately analyzed. <p>Results show distance measurement accuracy better than 1% and phase measurement accuracy better than 10 degrees for line lengths up to 5 km. These measurements exceed the performance of currently available TDR instruments.

Methyl-CpG-binding proteins (MeCP2, MBD1-MBD3) recruit transcriptional co-repressor molecules to methylated regions and silence transcription. The role of MBD2 in regulating brain function and behavior remains largely unexamined. To begin elucidating whether MBD2 influences neural function, I assessed the behavioral performance of Mbd2 null mice, compared their hippocampal electroencephalographic activity during exploration, and performed protein and mRNA expression assessments. The results indicate that mutant mice display a heightened anxiety-like behavior, diminished explorative activity and reduced sociability compared to wild-type mice. However, these behavioral differences were not paralleled by neurophysiological impairments. Mutant hippocampal and cortical samples display significantly elevated MeCP2 mRNA levels. Yet, MeCP2 protein expression did not mirror the mRNA profile and instead was significantly reduced. Glucocorticoid Receptor mRNA levels were significantly reduced in the hippocampus and cortex regions of Mbd2 null brains. The loss of MBD2 is sufficient to induce behavioral impairments in mice without introducing gross deficits in hippocampal neurophysiology.

Methyl-CpG-binding proteins (MeCP2, MBD1-MBD3) recruit transcriptional co-repressor molecules to methylated regions and silence transcription. The role of MBD2 in regulating brain function and behavior remains largely unexamined. To begin elucidating whether MBD2 influences neural function, I assessed the behavioral performance of Mbd2 null mice, compared their hippocampal electroencephalographic activity during exploration, and performed protein and mRNA expression assessments. The results indicate that mutant mice display a heightened anxiety-like behavior, diminished explorative activity and reduced sociability compared to wild-type mice. However, these behavioral differences were not paralleled by neurophysiological impairments. Mutant hippocampal and cortical samples display significantly elevated MeCP2 mRNA levels. Yet, MeCP2 protein expression did not mirror the mRNA profile and instead was significantly reduced. Glucocorticoid Receptor mRNA levels were significantly reduced in the hippocampus and cortex regions of Mbd2 null brains. The loss of MBD2 is sufficient to induce behavioral impairments in mice without introducing gross deficits in hippocampal neurophysiology.

Digital subscriber line (DSL) technology is used to provide high speed Internet access and, more recently, video services over twisted pair lines. Telephone lines have impairments that hinder DSL transmission, and some examples are coils and bridge taps that were introduced to aid voice telephony. Other faults are caused by physical damage that results in open circuits, short circuits or water in the line. Telephone companies have to locate and repair these faults to enable high-speed data services. It is also useful to qualify lines for future DSL service so that a new customer can be promptly informed whether high-speed service can be supplied. <p>This thesis proposes a novel technique called Wideband frequency domain reflectometry (W-FDR) to accurately locate impairments in telephone lines and estimate the reflection magnitude caused by faults. The measurement produces a result similar to the well-known time domain reflectometer (TDR), however, digital signal processing techniques are now applied to provide enhanced resolution and range. In addition to magnitude, the new technique is able to measure reflection angle which can help to determine the nature of the fault (wire in the cable, broken wires, etc). <p>The measurement technique consists of energizing the line with a sinusoid that increases from 50 kHz to 1300 kHz in discrete frequency steps after coherent detection. The amplitude of the reflected signal is recorded as a function of frequency for 2500 equally spaced frequencies. The Fourier transform and some signal processing are then used to estimate the complex reflection coefficient location of the faults in the telephone line. Lines with up to 4 reflection points have been accurately analyzed. <p>Results show distance measurement accuracy better than 1% and phase measurement accuracy better than 10 degrees for line lengths up to 5 km. These measurements exceed the performance of currently available TDR instruments.