No description available.

No description available.

No description available.

This thesis investigates our sensitivity to social signals from the face, both in health and disease, and explores some of the methodologies employed to measure them. The first set of experiments used forced choice and free naIll1ng paradigms to investigate the interpretation of a set of facial expressions by Western and Japanese participants. Performance in the forced choice task exceeded that measured in the free naming task for both cultures, but the Japanese participants were found to be particularly poor at labelling expressions of fear and disgust. The difficulties experienced with translation and interpretation in these tasks led to the development of a psychophysical paradigm which was used to measure the signalling strength of facial expressions without the need for participants to interpret what they saw. Psychophysical tasks were also used to measure sensitivity to eye gaze direction. A 'live' and screen-based task produced comparable thresholds and revealed that our sensitivity to these ocular signals was at least as good as Snellen acuity. Manipulations of the facial surround in the screen-based task revealed that the detection of gaze direction was facilitated by the presence of the facial surround and as such it can be assumed that gaze discriminations are likely to be made in conjunction with other face processing analyses. The tasks developed in these chapters were used to test two patients with bilateral amygdala damage. Patients with this brain injury have been reported to experience difficulties in the interpretation of facial and auditory signals of fear. In this thesis, their performance was found to depend on the task used to measure it. However, neither patient was found to be impaired in their ability to label fearful expressions compared to control participants. Instead, patient SE demonstrated a consistently poor performance in his ability to interpret expressions of disgust. Vll Experiments 2, 3, 4 and 5 of Chapter 3, have also been reported in Perception, 1995, Vol. 24, Supplement, pp. 14. The Face as a long distance transmitter. Jenkins, J., Craven, B. & Bruce, V. Experiments 1,2,3 and 4 of Chapter 3 were also reported in the Technical Report of the Institute of Electronics Information and Communication Engineers. HIP 96-39 (1997-03). Methods for detecting social signals from the face. Jenkins, J., Craven, B., Bruce, V., & Akamatsu, S. Experiments 2 and 5 of Chapter 3, and a selection of the patient studies from Chapter 6 were reported at the Experimental Psychology Society, Bristol meeting, 1996, and at the Applied Vision Association, Annual Meeting, April, 1996. Sensitivity to Expressive Signals from the Human Face: Psychophysical and Neuropsychological Investigations. Jenkins, J., Bruce, V., Calder, A., & Craven, B.

No description available.

Bacterial polyketides possess an enormous range of chemical diversity and biological function. Many polyketides such as tetracycline, epothilone, and rapamycin have been developed into key clinical pharmaceuticals in a broad range of therapeutic areas. Sequencing of bacterial genomes has shown that there are many more polyketide biosynthetic pathways than there are polyketides isolated from standard cultivation techniques. These genetically encoded polyketide natural products from cultivatable and uncultivatable bacteria represent one of the greatest remaining untapped reservoirs of new natural product diversity. To access this untapped diversity of polyketide products, a general method for heterologous expression of these pathways is needed. Heterologous expression has proven to be a valuable asset in the discovery, production, engineering, and characterization of bacterial secondary metabolites and the complex enzymology involved in their biosynthesis. Herein we discuss the development and investigation of two unique heterologous expression platforms utilizing host strains of Myxococcus xanthus and Escherichia coli. Using our developed heterologous hosts, we were able to produce the Streptomyces rimosus polyketide oxytetracycline. Through production of oxytetracycline in E .coli we have identified the potential of alternative transcription factors as regulators of secondary metabolism. Further investigation and development of alternative transcription factors as regulators of secondary metabolism in heterologous hosts could benefit the development of robust general methodology for the heterologous expression of polyketides.

Previous studies show that recovering alcoholics exhibit deficits in perceiving facial affect. The present study investigates whether these deficits are present prior to the onset of alcoholism. Participants with a family history of alcoholism (FHP) and participants without such a family history (FHN) selected the emotion label they felt most closely corresponded with stimuli viewed on a computer screen. Zuckerman's Sensation Seeking Survey was also completed. The data revealed a relationship between family history of alcoholism and the perception of facial expressions. Additionally, FHP participants were higher in sensation seeking compared to FHN participants and high sensation seekers were less accurate in categorizing fearful expressions. Disinhibition and boredom susceptibility were identified as the traits driving the effect between sensation seeking and fear categorization accuracy. An account of how these traits may be associated with both decreased fear perception and a greater risk for alcoholism is discussed, and future research directions suggested.

No description available.

The advent of microarray technology, allowing measurement of gene expression levels for thousands of genes in parallel, has made possible experiments designed to investigate the genetic control of variation in gene expression level (described in the literature as ???genetical genomics??? or ???eQTL??? experiments). Published results from these studies, in yeast and in mice, show that genetic variation is an important factor in gene regulation, and furthermore that individual polymorphisms modify the expression level of many genes. The concern of this thesis is the bioinformatic analyses of the expression level and genotype data sets that are the raw material for these studies. In particular this thesis addresses the two issues of detection of artefactual effects, and maximizing the information that can be extracted from the data. It is shown that while a polymorphism affecting the expression of many genes may be readily detected, care must be taken to determine whether the detected effect is genuinely one of genetic control of expression level, rather than the effect of correlations in measured expression level not of genetic cause. A significance test is devised to distinguish between these cases. The detection of artefactual correlation is explored further in the reanalysis of the published data from a large yeast study. A critique is given of the permutation method used to ascribe genetic control as the cause of inter gene expression level correlation. The presence of some degree of artefactual correlation is shown, and novel methods are presented for identifying such artefacts. To extend the analyses that may be applied to eQTL data, an algorithm is presented for determining secondary eQTLs for gene expression level (as opposed to a single primary QTL), along with a significance test for the putative QTL found. The technique is demonstrated on a large public data set. In addition to the use for which they are intended, the data sets generated for eQTL studies provide opportunities for additional analyses. In this thesis a method is developed for calculating a genome wide map of meiotic recombination frequency from the genotype data for multiple segregant strains. The method is demonstrated on the published genotype data generated for a large yeast eQTL study.

Typescript (photocopy) / 194 leaves, [19] leaves of plates : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Biochemistry, 1981