Showing papers by "Queensland University of Technology published in 1994"

Apoptosis. Its significance in cancer and cancer Therapy

Abstract: Apoptosis is a distinct mode of cell death that is responsible for deletion of cells in normal tissues; it also occurs in specific pathologic contexts. Morphologically, it involves rapid condensation and budding of the cell, with the formation of membrane-enclosed apoptotic bodies containing well-preserved organelles, which are phagocytosed and digested by nearby resident cells. There is no associated inflammation. A characteristic biochemical feature of the process is double-strand cleavage of nuclear DNA at the linker regions between nucleosomes leading to the production of oligonucleosomal fragments. In many, although not all of the circumstances in which apoptosis occurs, it is suppressed by inhibitors of messenger RNA and protein synthesis. Apoptosis occurs spontaneously in malignant tumors, often markedly retarding their growth, and it is increased in tumors responding to irradiation, cytotoxic chemotherapy, heating and hormone ablation. However, much of the current interest in the process stems from the discovery that it can be regulated by certain proto-oncogenes and the p53 tumor suppressor gene. Thus, c-myc expression has been shown to be involved in the initiation of apoptosis in some situations, and bcl-2 has emerged as a new type of proto-oncogene that inhibits apoptosis, rather than stimulating mitosis. In p53-negative tumor-derived cell lines transfected with wild-type p53, induction of the gene has, in rare cases, been found to cause extensive apoptosis, instead of growth arrest. Finally, the demonstration that antibodies against a cell-surface protein designated APO-1 or Fas can enhance apoptosis in some human lymphoid cell lines may have therapeutic implications.

How do you Make it to the Top? An Examination of Influences on Women's and Men's Managerial Advancement

Abstract: Confirmatory modeling was used to test models of situational and individual influences on women's and men's managerial advancement. Although an overall model fitted the data well, separate models f...

Polynomial Wigner-Ville distributions and their relationship to time-varying higher order spectra

Abstract: The Wigner-Ville distribution (WVD) has optimal energy concentration for linear frequency modulated (FM) signals. This paper presents a generalization of the WVD in order to effectively process nonlinear polynomial FM signals. A class of polynomial WVD's (PWVD's) that give optimal concentration in the time-frequency plane for FM signals with a modulation law of arbitrary polynomial form are defined. A class of polynomial time-frequency distributions (PTFD's) are also defined, based on the class of PWVD's. The optimal energy concentration of the PWVD enables it to be used for estimation of the instantaneous frequency (IF) of polynomial FM signals. Finally, a link between PWVD's and time-varying higher order spectra (TVHOS) is established. Just as the expected value of the WVD of a nonstationary random signal is the time-varying power spectrum, the expected values of the PWVD's have interpretations as reduced TVHOS. >

Multistage secret sharing based on one-way function

Abstract: The concept of multistage secret sharing (MSS) is proposed and a general implementation of MSS schemes given. In such a scheme, many secrets are shared in such a way that all secrets can be reconstructed separately. Each share is of the same size as that of any single shared secret.

Accuracy of stereolithographic models of human anatomy

Abstract: A study was undertaken to determine the dimensional accuracy of anatomical replicas derived from X-ray 3D computed tomography (CT) images and produced using the rapid prototyping technique of stereolithography (SLA). A dry bone skull and geometric phantom were scanned, and replicas were produced. Distance measurements were obtained to compare the original objects and the resulting replicas. Repeated measurements between anatomical landmarks were used for comparison of the original skull and replica. Results for the geometric phantom demonstrate a mean difference of +0.47 mm, representing an accuracy of 97.7-99.12%. Measurements of the skull produced a range of absolute differences (maximum +4.62 mm, minimum +0.1 mm, mean +0.85 mm). These results support the use of SLA models of human anatomical structures in such areas as pre-operative planning of complex surgical procedures. For applications where higher accuracy is required, improvements can be expected by utilizing smaller pixel resolution in the CT images. Stereolithographic models can now be confidently employed as accurate, three-dimensional replicas of complex, anatomical structures.

Research students' early experiences of the dissertation literature review

Abstract: The phenomenon of a dissertation literature review is explored from a "second-order" perspective. Written responses from 41 neophyte research scholars from various disciplines in an Australian university were gathered in response to two questions: "What do you mean when you use the words "literature review"?" and "What is the meaning of a literature review for your research?" A phenomenographic analysis identified six conceptions, or ways of experiencing, literature reviews: literature review as a list, literature review as a search, literature review as a survey, literature review as a vehicle for learning, literature review as a research facilitator, and literature review as a report. The conceptions represent differing relations between student researchers and the literature. The range of conceptions suggests that the supervisors of postgraduates and other teachers interested in the literature review process need to accept literature reviews as a problem area for students and develop strategies to help them.

Effect of Visual Impairment on Driving

Abstract: The aim of the study was to determine the effect on driving of restricting vision. This was undertaken by comparing the driving performance of young, normal subjects under conditions of simulated visual impairment with a baseline condition. Visual impairment was simulated using goggles designed to replicate the effects of cataracts, binocular visual field restriction, and monocular vision. All subjects had binocular visual acuity greater than 6/12 when wearing the goggles and thus satisfied the visual requirements for a driver's license. Driving performance was assessed on a closed-road circuit for a series of driving tasks including peripheral awareness, maneuvering, reversing, reaction time, speed estimation, road position, and time to complete the course. Simulated cataract resulted in the greatest detriment to driving performance, followed by binocular visual field restriction. The monocular condition did not significantly affect driving performance for any of the driving tasks assessed.

Evidence for two groups of banana bunchy top virus isolates

Abstract: Banana bunchy top virus (BBTV) DNA component 1 from isolates from 10 different countries was cloned and sequenced and the sequences were aligned and compared. This analysis indicated two groups: the South Pacific group (isolates from Australia, Burundi, Egypt, Fiji, India, Tonga and Western Samoa) and the Asian group (isolates from the Philippines, Taiwan and Vietnam). The mean sequence difference within each group was 1.9 to 3.0% and between isolates from the two groups was approximately 10%, but some parts of the sequences differed more than others. However, the protein encoded by the major open reading frame, which is probably a replicase, differed by approximately 5%. The region from the beginning of the stem-loop sequence to the potential TATA box was identical in all isolates except for a two nucleotide change in the Western Samoan isolate and a single change in that of the NSW isolate. These results, together with other evidence, suggest that BBTV has spread to bananas after the initial movement of bananas from the Asian Pacific regions to Africa and the Americas.

Men and Women Managers' Advancement: Personal or Situational Determinants?

Abstract: Ce travail s'est donne pour objectif l'etude de l'importance relative des facteurs personnels et environnementaux dans l'avancement des femmes cadres. On a suppose a priori que l'avancement des ces femmes etait plus en rapport avec leur travail et leur statut prive qu'avec leurs attitudes ou leur socialisation precoce. En outre, des differences liees au sexe ont ete introduites pour rendre compte de l'impact sur l'avancement des variables personnelles et des situations specifiques. Des donnees ont ete recoltees par questionnaire aupres de cadres australiens repartis sur six echelons, 654 femmes et 616 hommes. L'avancement etait operationnalise par la promotion et l'echelon. Des analyses de regression ont montre que pour les femmes l'avancement etait plus en relation avec la situation qu'avec les variables personnelles

Age Differences in Adolescent Future-Oriented Goals, Concerns, and Related Temporal Extension in Different Sociocultural Contexts.

Abstract: The aim of this study was to investigate the extent to which differences in agegraded sociocultural contexts influence adolescent future-oriented goals, concerns, and related temporal extension. Ninety-five 13–14-year-old Australian boys and 104 girls, 87 16–17-year-old Australian boys and 81 girls, 67 13–14-year-old Finnish boys and 86 girls, and 56 16–17-year-old Finnish boys and 107 girls were investigated. Half of the subjects in each group came from an urban environment and half from rural regions. The subjects filled in the Hopes and Fears Questionnaire measuring the content and temporal extension of goals and concerns. Overall, the results showed that adolescent goals, concerns, and related temporal extension reflected the major developmental tasks of their own age and early adulthood. However, interesting cross-cultural, gender, and urban rural differences were also found, reflecting variation in societal options and cultural values. For example, Australians were more interested in leisure and more concerned about their own health and global issues. Later school transitions meant that in older age groups the Finnish adolescents expected goals related to their future education and occupation to be actualized later than Australian youths did. Because of a lack of career options, interest in a future occupation decreased with age among adolescents living in rural regions.

Papaya ringspot potyvirus: isolate variability and the origin of PRSV type P (Australia).

Abstract: We have sequenced the coat protein gene of nine isolates of papaya ringspot virus (PRSV) including six Australian and three Asian isolates and compared these with four previously reported sequences of PRSV. There was up to 12% sequence variation between isolates at the nucleotide level. However, there was no significant difference between the sequences obtained from Australian isolates irrespective of whether they were PRSV type P (cucurbit or papaya infecting) or PRSV type W (cucurbit infecting) and these isolates were more closely related to one another than to any other isolate. These results imply that PRSV-P, first recorded in Australia in 1991, arose locally from PRSV-W (first recorded in Australia in 1978) rather than being introduced. Further, there was no consistent sequence difference between PRSV-P and PRSV-W isolates that would obviously account for their host range difference.

Coping resources, coping strategies and adjustment to organizational change: Direct or buffering effects?

Abstract: This study examined the effects of personal and social resources, coping strategies and appraised stress on employees' levels of anxiety and depression. In relation to the effects of resources and coping strategies, two different models were tested. The main effects model proposes that, irrespective of the level of stress, coping resources and coping strategies have direct effects on well-being. In contrast, the buffering model predicts that the buffering effects of coping resources ad strategies are only evident at high levels of stress. One hundred lawyers completed a structured self-administered questionnaire that measured their personal and social resources, use of problem-focused and emotion-focused coping strategies, and appraisals of the stressfulness of the situation. Results revealed generally strong support for the main effects model in the prediction of employee levels of anxiety and depression. Lower levels of anxiety were linked to judgements of lower levels of organizational change,...

Analytic signal generation-tips and traps

Abstract: In this correspondence we discuss methods to produce the discrete analytic signal from a discrete real-valued signal. Such an analytic signal is complex and contains only positive frequencies. Its projection onto the real axis is the same as the original signal. Our use stems from instantaneous-frequency estimation and time-frequency signal analysis problems. For these problems the negative frequency component of real signals causes unwanted interference. The task of designing a filter to produce an approximation to the ideal analytic signal is not as simple as its formulation might suggest. Our result is that the direct methods of zeroing the negative frequencies, or using Hilbert transform filters, have undesirable defects. We present an alternative which is similar to the "quadrature" filters used in modem designs. >

Respondent Lobbying in the Australian Accounting Standard‐setting Process: ED49 – A Case Study

Abstract: Aims to contribute to the understanding of the Australian standard‐setting due process. Analyses submissions made on Exposure Draft 49 Accounting for Identifiable Intangible Assets (ED49) as a case study of the strategies employed by lobbyists in their attempt to influence the accounting standard setters. Previous studies on respondents′ submissions have ignored the possibility that, in responding to exposure drafts, lobbyists are provided with a means of persuasion in excess of casting votes. Employs a form of content analysis to study the political process of standard setting. The results suggest that respondents on ED49 attempted to weight their lobby positions with the use of supporting arguments that utilized conceptual and/or economic consequences rationale and presented positions of differing strengths.

The nature of the small firm : understanding the motivations of growth and non-growth oriented owners

Abstract: The small business sector is of primary interest to government policy (see Beddall 1990). This has been observed through a number of initiatives, including the creation of “free” or subsidised advisory services. The existence of such advisory services has at least two rationales. First, assistance to persons intending to start their own business (particularly for the first time) is accepted as a community service obligation and involves maximising the likelihood of success of small business initiatives, while at the same time protecting potential owners, and the parties they might contract with, from the costs of financial distress. This in turn presumes that such problems cannot be satisfactorily resolved through the market for business advice. Second, free advisory services to established businesses are justified on the premise that they increase the efficiency of the sector (again in a manner or extent not available through market processes) so as to increase the wealth of the economy in general and contribute to employment, in particular. To achieve this latter objective, government advisory services need to identify the attributes of businesses which are more likely to have growth prospects. But an operational framework that distinguishes growth from nongrowth small businesses does not exist. This paper represents an attempt to develop such a framework. We initially discuss the nature of small business, review prior attempts to define the sector and propose a definition that links the literature to financial economics. We then review the literature to consider the different attributes of small business that are likely to be indicative of growth potential. Finally, we report the results of a set of structured interviews with small business owners and develop a set of propositions concerning the fundamental characteristics of growth compared to non-growth firms.

Snake venoms affecting the haemostatic mechanism--a consideration of their mechanisms, practical applications and biological significance.

Abstract: Snake venoms contain a rich variety of factors affecting the haemostatic mechanism which can be broadly classified as possessing coagulatant, anticoagulant and haemorrhagic activity. Coagulant enzymes include activators of blood coagulation factors II (prothrombin), V and X; anticoagulants include protein C activators, inhibitors of prothrombin complex formation and fibrinogenases which can be further classified according to their specificity for the alpha-, beta- and gamma-chains of fibrinogen. Intermediate between true coagulants and true anticoagulants are the thrombin-like enzymes which bring about clotting in vitro but defibrination (anticoagulation) in vivo. Snake venoms also affect platelets either by inducing or inhibiting platelet aggregation and cause haemorrhage via an action on platelets or via proteolysis of the blood vessel wall. Haemorrhagins also include inter alia, the alpha-fibrinogenases. This rich diversity of snake venom components affecting haemostasis has enabled a range of practical applications to be established including therapeutic anticogulation with thrombin-like enzymes (Ancrod and Defibrase) and laboratory tests for individual haemostatic factors (protein C, prothrombin, factor X and lupus anticoagulant). This broad spectrum of materials in snake venoms suggests some evolutionary advantage to the venom producer, not only for dispatching prey but as agents which 'spread' the venom toxins throughout the body and initiate digestion.

Tertiary Students' Knowledge of Their Own Learning and a SOLO Taxonomy.

Abstract: This paper is a report of the analysis of statements by 869 students and their 21 lecturers in 12 courses in 5 Faculties in the Queensland University of Technology (QUT). The students and lecturers were asked to write a page about learning. The objectives were to collect data to devise a taxonomy of levels of knowledge of learning held by tertiary students and lecturers and to use this to describe student knowledge to lecturers as a basis for planning for teaching. The statements were categorised, using the SOLO Taxonomy as a model (c.f., Biggs and Collis 1982, 1989), by two trained researchers and checked by the author and a consultant. The majority of responses for both students and lecturers were multistructural. A MANOVA for SOLO levels by deep, surface and achieving motives and strategies showed that as SOLO levels increased surface motives declined and deep motives and strategies assumed more importance. The key concepts in learning identified by a random sample of 100 students were further analysed and described for each SOLO level. A SOLO type model of levels of knowledge of learning is proposed, based on the structure of the responses.

Subject instructions and methods of target presentation in accommodation research.

Abstract: PURPOSE: The authors investigated the potential of subject instructions to alter the static accommodative stimulus-response function. They also investigated whether the reduced cue environment of the Badal optical system leads to accommodative responses different from those that occur for targets presented in real space. METHODS: Static accommodative responses with three focusing instructions were compared to baselines obtained with minimal instruction to stabilize gaze. Static accommodative responses were recorded for targets presented in real space and in a Badal optical system. RESULTS: Individuals differ widely in their responses to Instruction 1 (" ... make no special effort ... "), although some adopt a relatively fixed position of focus. Responses with Instruction 2 (" ... look at the words naturally ... ") and Instruction 3 (" ... carefully focus ... ") are not significantly different from each other, but differ slightly from the responses with the baseline instruction ("pick a word in the middle of the block of text and look at it"). In a sample including most subjects, mean responses for Badal and real space targets are identical. However, it appears that some subjects have difficulty accommodating for Badal targets. CONCLUSIONS: The authors recommend the use of Instructions 2 and 3 for investigation of the static accommodative response, with a number of provisos. Accommodative responses to Badal and real space targets are generally equivalent, but researchers should take care to identify those persons who have difficulties accommodating for Badal targets.

Subject Instructions and Methods of Target Presentation in Accommodation Research

Abstract: Purpose. The authors investigated the potential of subject instructions to alter the static accommodative stimulus-response function. They also investigated whether the reduced cue environment of the Badal optical system leads to accommodative responses different from those that occur for targets presented in real space. Methods. Static accommodative responses with three focusing instructions were compared to baselines obtained with minimal instruction to stabilize gaze. Static accommodative responses were recorded for targets presented in real space and in a Badal optical system. Results. Individuals differ widely in their responses to Instruction 1 (". . .make no special effort. . ."), although some adopt a relatively fixed position of focus. Responses with Instruction 2 (". . .look at the words naturally. . .") and Instruction 3 (". . .carefully focus. . .") baseline instruction ("pick a word in the middle of the block of text and look at it"). In a sample including most subjects, mean responses for Badal and real space targets are identical. However, it appears that some subjects have difficulty accommodating for Badal targets. Conclusions. The authors recommend the use of Instructions 2 and 3 for investigation of the static accommodative response, with a number of provisos. Accommodative responses to Badal and real space targets are generally equivalent, but researchers should take care to identify those persons who have difficulties accommodating for Badal target.

The Relationship between Andragogical and Pedagogical Orientations and the Implications for Adult Learning

Abstract: Current literature suggests that the relationship between andragogy and pedagogy is based on a continuum. This study found that the relationship of andragogical and pedagogical orientations, measured by the Student's Orientation Questionnaire, is more correctly represented as being oithogonalorat right angles to each other. Such an orthogonal relationship reflects the complexities involved in adult learning. The paper discusses implications for both the learning process and for future research.

Embedding and probabilistic correlation attacks on clock-controlled shift registers

Abstract: Embedding and probabilistic correlation attacks on clock-controlled shift registers that are clocked at least once per output symbol are defined in general and are analyzed in the unconstrained case, with an arbitrary number of deletions at a time, and in the constrained case, with at most d deletions at a time. It is proved that the unconstrained embedding attack is successful if and only if the deletion rate is smaller than one half and if the length of the observed keystream sequence is greater than a value linear in the shift register length r. It is shown how to compute recursively the joint probability which is a basis for the unconstrained probabilistic attack with independent deletions. The efficiency of the attack is characterized in terms of the capacity of the corresponding communication channel with independent deletions and it is concluded that the probabilistic attack is successful for any deletion rate smaller than one if the given keystream sequence is sufficiently long, also linearly in r. It is proved that the constrained embedding attack is successful for any d and the minimum necessary length of the known output sequence is shown to be linear in r, and at least exponential and at most superexponential in d. This demonstrates that making d large can not ensure the theoretical security against the attack, but can considerably improve the practical security.

Critical subjective measurement of amplitude of accommodation.

Abstract: The use of fixed print size to measure amplitude of accommodation by the push-up method will result in a range of angular sizes of the print at the nearpoint for patients with different amplitudes. We investigated the effect of this on measured amplitude of accommodation in 60 subjects aged

Organizational Change: Relationship between Reactions, Behaviour and Organizational Performance

Abstract: Describes one aspect of a longitudinal case study conducted in an Australian college of advanced education undergoing transformation to a university and explores the relationship between the espoused and observed reaction by staff to the changes, their actual behaviour, and the performance of the organization. Findings from the research did not vindicate the assumption in the culture literature that organizational culture has a direct and predictable effect on organizational performance, as the organization performed very well according to stakeholders′ criteria, in spite of widespread opposition at both grass roots and middle management levels during a period of forced, rapid change. Qualitative evidence is given of the very negative reactions to the forced behaviour changes, while quantitative evidence is given of the level of performance achieved by the organization during the same period. The conclusion is drawn that, on an organization‐wide scale, whole patterns of staff behaviour may be changed with...

Investigating aboutness axioms using information fields

Abstract: This article proposes a framework, a so called information field, which allows information retrieval mechanisms to be compared inductively instead of experimentally. Such a comparison occurs as follows: Both retrieval mechanisms are first mapped to an associated information field. Within the field, the axioms that drive the retrieval process can be filtered out. Tn this way, the implicit assumptions governing an information retrieval mechanism can be brought to light. The retrieval mechanisms can then be compared according to which axioms they are governed by. Using this method it is shown that Boolean retrieval is more powerful than a strict form of coordinate retrieval. The salient point is not this result in itself, but how the result was achieved.