Temporal Selection in Dynamic Displays: Sensory Information Persists Despite Masking

The visual system receives a dynamic stream of information, but it has a limited capacity and must deploy its resources to behaviourally relevant stimuli - a process referred to as “attention”. Rapid serial visual presentation (RSVP) is an experimental method for investigating attention’s time course by presenting a rapid sequence of stimuli at a single location. Attentional selection in both naturalistic viewing and RSVP is limited by masking, and many models of selection in RSVP assume that masking terminates sensory memory for stimuli that are no longer present. However, there is indirect evidence that information about unselected RSVP stimuli may persist in a buffer despite masking. In this thesis we directly investigate buffering and selection of a cued item from one of multiple simultaneous RSVP streams. We use mixture modelling to analyse reports from only those trials in which participants identified a letter in response to the cue, and outline a novel quantitative test for buffering (Chapter 2). This provides new insights into the temporal variability of selection with exogenous and endogenous cues (Chapter 3). A series of experiments show that participants can select buffered representations, despite masking, and this appears to be related to the number of simultaneous RSVP streams (Chapter 4). We also investigate possible contributions of crowding and eccentricity to selection (Chapter 5). RSVP provides a measure of attention’s timing that replicates classic attentional effects. However, participants appear to dedicate attention to the streams prior to the cue’s appearance. When there are few streams, this leads to attentional speeds fast enough to select a stimulus representation that persists briefly, despite the masking inherent in RSVP. This falsifies theoretical claims about masking in RSVP, and demonstrates that the dynamic nature of naturalistic viewing does not prevent selection from sensory memory

Re-imagining Navan Fort : new light on the evolution of a major ceremonial centre in Northern Europe

Peer reviewedPublisher PD

December 1957

Editor-in-Chief: Thomas Ludowici, Associate Editor: Anthea Collett, Photo and Layout Editor: Kevin Moore, Literary Editor: Arthur Patrick, Graduates Editor: Verlie Edwards, Business and Advertising Manager: Neil Hughes, Circulation Manager: Errol Wright, Secretaries: Frances Brennan, Marjorie McGraw, Faye Millsom, Margaret Scott, and Jill Eason. Photographer: Bert Chow, Faculty Advisor: Dr. A. P. Salom, Printer: Avondale Press, Cooranbong.https://research.avondale.edu.au/jacaranda/1021/thumbnail.jp

The Phytophthora nicotianae zoospore secretome

Plants and their pathogens are continually co-evolving in what has been referred to as an evolutionary arms race. In this struggle between pathogen and host, the adaptation of one can lead to a selective pressure and in turn a counter-adaptation of the other. The selective pressure on secreted pathogen proteins is particularly high as these proteins have functions vital to successful infection and maintaining a parasitic relationship. In this thesis a proteomics approach was taken to investigate the proteins secreted during the initial stages of infection of Phytophthora nicotianae. This pathogen belongs to the Oomycetes, which includes many destructive plant pathogenic species. The diseases caused by these species affect many different plant hosts and impact not only agricultural production but also native ecosystems. During the initial stages of plant infection by P. nicotianae, motile zoospores locate an appropriate infection site and undergo encystment where they detach both flagella, form a cell wall and secrete proteins from three types of peripheral vesicles found in the zoospore cortex. In Chapter 2, the timing of synthesis of four proteins (Cpa, Lpv, PnCcp and Vsv) found in these vesicles was investigated during asexual sporulation. The results showed differences in the time at which Cpa, Lpv, PnCcp and Vsv were synthesised. In addition, the timing of expression of Lpv, PnCcp and Vsv genes was examined in sporulating hyphae, zoospores and 3h germinated cysts. It was found that these genes had different expression patterns. In preparation for the identification and characterisation of P. nicotianae transformants in which one of these secreted proteins, namely PnCcp, was silenced, assays for screening and analysing transformants were developed. While sequence motifs in PnCcp and Vsv indicate that these two proteins are likely to have adhesive properties, their function has not been directly demonstrated. In Chapter 3, an RNAi gene silencing approach was used to investigate the function of PnCcp. Chapter 4 focused on an investigation of protein secretion during zoospore encystment. Firstly, spatial and temporal patterns of secretion of the four peripheral vesicle proteins were determined. Lpv was found not to be secreted and there were differences in the timing of secretion of the other three proteins with Cpa being secreted earlier than Vsv and PnCcp. Secondly, proteomic and bioinformatic approaches were used to investigate proteins secreted during zoospore encystment. This analysis led to the identification of a number of proteins in extracts solubilised from encysted zoospores and 29 of these were predicted to have N-terminal secretion signals by SignalP. The majority of these proteins had unknown functions, highlighting the need for more research in this area. Other putative secreted proteins were involved in carbohydrate and protein metabolism. Together, the research reported in this thesis sheds new light on the synthesis and secretion of zoospore vesicle proteins and provides a foundation for further research aimed at characterising the function of these proteins

An Exploration Of The Needs Of, And Possibilities Of Ministry To, Geographically Isolated Seventh-day Adventists

Problem There are some Seventh-day Adventist Church members who, because of mileage distance or other geographic reason, are unable to attend a local church regularly, and whose membership is listed on the conference church roll. If the church is to minister to all its members, this segment cannot be ignored. The geographically isolated members have received very little pastoral nurture, and they have experienced only limited fellowship. As a result, generally they have maintained a weakened connection with the church at large. Because the seventh- day Sabbath is a central aspect of belief and worship practice, it is meaningful for Seventh-day Adventists to find fellowship with those of like faith. Method The intent of this project was to explore the needs of, and possibilities of ministry to, geographically isolated Seventh-day Adventists in Indiana, United States of America, and Ontario, Canada. A theology of the church must not exclude those who are unable to participate in corporate worship. The biblical understanding of the believer as a priest and the church as a ministry community is essential when the geographically isolated are considered. A questionnaire was used to gather data concerning the environment and indicators of spirituality of the group. From this a membership profile emerged. It was then determined that a brief pastoral nurture process should be undertaken in an endeavor to enrich their spirituality. A three-lesson Bible correspondence course on spiritual gifts was developed and given to a selected sample. Shortly after the completion of this course, the first part of the questionnaire was readministered, and there was found to be only a slight increase in spirituality (.09) . Recommendations A program of pastoral nurture is needed to involve the isolated more personally in the life and mission of the church. The project suggested the following for a developing ministry: (1) a pastor to the isolated should be appointed to care for the personal and spiritual needs of the isolated; (2) his responsibilities would include those of a local church pastor, adapted to the isolated\u27s environment; (3) methods would need to be employed so that this ministry is personalized to each isolated member; (4) an annual retreat exclusively for the isolated should be conducted; (5) brief correspondence courses should be available; (6) a cassette ministry should be available; (7) assistance should be given for Christian education; and (8) witnessing training should be offered

Mixed Hybrid Go/No-Go with eye-tracking

Data collection began: 4/8/1

The generality of the critical spacing for crowded optotypes: From Bouma to the 21st century.

It is rare to find a crowding manuscript that fails to mention Boumas law, the rule of thumb stating that flankers within a distance of about one half of the target eccentricity will induce crowding. Here we investigate the generality of this rule (even for just optotypes), the factors that modulate the critical spacing, and the evidence for the rule in Boumas own data. We explore these questions by reanalyzing a variety of studies from the literature, running several new control experiments, and by utilizing a model that unifies flanked identification measurements between psychophysical paradigms. Specifically, with minimal assumptions (equivalent psychometric slopes across conditions, for example), crowded acuity can be predicted for arbitrary target sizes and flanker spacings, revealing a performance landscape that delineates the critical spacing. Last, we present a compact quantitative summary of the effects of different types of stimulus manipulations on optotype crowding