The Isolation of Human Rod and Cone Photoreceptor Activity combining Electroretinography and Silent Substitution Techniques

Aims: The electroretinogram (ERG) can be used to independently assess the function of rod and cone photoreceptors within the human retina. The work in this thesis sought to investigate an alternative method of recording the ERG, using the silent substitution paradigm (Estevez and Spekreijse 1982). The aims are separated into two parts, firstly, the isolation and characterisation of the non-dark adapted rod photoreceptor response, and secondly, characterising the ERG response from L-, M- and S-cones. Methods: Rod, L-, M- and S-cone isolating as well as non-isolating sinusoidal flicker and transient square-wave stimuli were generated on a 4 primary LED ganzfeld stimulator to elicit ERGs from non-dark adapted participants with normal and compromised rod or cone function. Results: The results from the rod experiments showed that ERGs elicited by rod isolating silent substitution stimuli exhibit low-pass temporal frequency response characteristics with an upper response limit of 30Hz and saturate beyond 1000ph Td. Responses are optimal between 5 – 8 Hz and between 10-100 photopic Td. There is a significant correlation between the response amplitudes obtained with the silent substitution method and current standard clinical protocols. The results from the cone experiments showed that the L-, M- and S-cone stimulation produced ERGs with very different morphologies. L- and M-cone stimulation is of limited use as an objective measure of colour vision deficiency. Conclusion: Silent substitution provides an effective method for the isolation of human rod and cone photoreceptor function in subjects when stimuli are used within appropriate parameter ranges

Bibliographies of reading source materials and a skills directory for teachers of reading

Thesis (Ed.M.)--Boston Universit

The question of ‘alternatives’ within food and drink markets and marketing: introduction to the special issue

The question of 'alternatives' within food and drink markets and marketing: introduction to the special issu

The Supreme Court Justice from Knoxville: The Politics of the Appointment of Justice Edward Terry Sanford

The articles written on Justice Edward Terry Sanford are limited in scope and contain several inaccuracies. While his early life has been covered, there has not been a great deal of attention paid to the politics of his appointment to the Supreme Court. It has been the purpose of this study to present an analysis of the circumstances surrounding the appointment of Edward Terry Sanford to the United States Supreme Court with an examination of the role played by Sanford\u27s former law partner, James A. Fowler, in influencing the individuals charged with making the appointment. According to criteria spelled out by Blaustein and Mersky, Sanford was typical of the justices who have been appointed to the Supreme Court. The majority of the justices who have gained admittance to this exalted position fit a particular mold. They have, for the most part, come from families of above average financial means, who have been involved in politics or public service and whose economic circumstances have provided cultural and educational advantages available to middle and upper class individuals. Most of the members of the Court have come from religions with high social status--Presbyterian, Episcopal, Congregational, and Unitarian. While the Constitution does not prescribe any particular educational criteria a nominee must meet to gain appointment to the Court, all appointees have by custom been lawyers. Almost seventy-five percent of the appointees were educated in better institutions--with Harvard, Yale and Columbia being those most frequently represented--or have received their legal training through reading law under first-rate lawyers and judges. Sanford, the product of an economically advantaged environment, educated at Harvard, an Episcopalian, and extremely active in community affairs, fit the mold of the successful supreme court appointee. The point to be considered in this study is why Sanford was selected over other equally capable candidates

The Coherent File Distribution Protocol

CFDP is a protocol that takes advantage of the broadcast nature of CSMA networks to speed up simultaneous one-to-many file transfers (e.g., when booting diskless workstations). The CFDP server listens and services requests for entire files or portions thereof. CFDP clients first determine whether the file they are interested in is already being transferred, in which case they "eavesdrop" and load as much of it as they can, or they initiate a new transfer. The clients timeout when the server stops transmitting, and if they are still missing parts of the file they request them with a block-transfer request. CFDP is a back-end protocol a front end is needed to handle naming and security issues. A simple such front end is also presented here

Graduate Work-Readiness in the 21st Century

The term ‘graduateness’ is beginning to be used, nationally and internationally, to describe a range of competences thought to match the demands of the workplace. There is no accompanying unifying definition, nor framework for formal recognition, rather it is used to imply a combination of attributes that varies between types of Higher Education Institutions across the World. In Ireland, the desirable characteristics of 21st century graduates variously include qualities of being ‘Creative and Enterprising, Solution-Orientated, Effective Communicators, and Globally Engaged Active Leaders’ (DCU 2014). Similarly, they should be engaged, enterprising, enquiry-based, effective and expert in their chosen field (DIT, 2013). While the value of these qualities is not contested here, they may be more appropriate to individuals who are growing in their professional maturity, but less so in their first encounter with work. This paper argues that 21st century graduates should be supported in their transition to the world of work by being equipped with the resources to assimilate the activities of their host rapidly, to assess how their particular role is situated, supplied, and constrained, and appreciate its associated expectations, risks and consequences. Graduate success in the workplace could be underpinned by a methodology that guides formative reflection and develops their ability to evaluate work experiences, both actual and vicarious, within a framework that captures, recognises and reinforces the depth of their tacit learning. This approach may help create a solid foundation for long-term employability, enable the realisation of 21st Century Graduate attributes, and presage their formal recognition, at home and beyond, in the fullest sense. The authors offer a comprehensive workplace-specific protocol and an accompanying methodology that enables graduates not only to assert that they are work-ready, but to provide the evidence