Journal and Proceedings of
The Royal Society of New South Wales
Volume 137 Parts 3 and 4
Gemstone Characteristics, North-East Barrington Plateau, NSW
D.L. Roberts, F.L. Sutherland, J.D. Hollis, P. Kennewell and I.T. Graham
Abstract: Corundum and zircon concentrates from gravel deposits in two northern Barrington plateau prospects were studied for their features, to investigate potential gemstone sources within the catchment zone. The studies utilized field research, colour sorting, gemmological microscopy, EDAX and PIXE trace element analysis and zircon fission-track dating. The results showed statistical differences in corundum suites from different gravel horizons, which suggested different source areas. Anorthoclase and ilmenorutile were identified as inclusions in Barrington corundums for the first time. Zircon fission-track results showed that several episodes of volcanic eruptions were involved (66-4,Ma), reinforcing and adding to previous eruption ages. This suggests multiple corundum delivery both in space and time into drainage systems.
Keywords
Corundum, ruby, gravels, terraces, eruption, trace elements, mineral
inclusions, zircon, gemstone sources.
Studies on Aragonite and its Occurrence in Caves, including New South Wales Caves
Jill Rowling
Abstract: Aragonite is a minor secondary mineral in many limestone caves throughout the world and is probably the second-most common cave mineral after calcite. It occurs in the vadose zone of some caves in New South Wales. Aragonite is unstable in fresh water and usually reverts to calcite, but it is actively depositing in some NSW caves.
A review of the cave aragonite problem showed that chemical inhibitors to calcite deposition assist in the precipitation of calcium carbonate as aragonite instead of calcite. Chemical inhibitors physically block the positions on the calcite crystal lattice which otherwise would develop into a larger crystal. Often an inhibitor for calcite has no effect on the aragonite crystal lattice, thus favouring aragonite depositition.
Several factors are associated with the deposition of aragonite instead of calcite speleothems in NSW caves. They included the presence of ferroan dolomite, calcite-inhibitors (in particular ions of magnesium, manganese, phosphate, sulfate and heavy metals), and both air movement and humidity.
Keywords
aragonite, cave minerals, calcite, New South Wales
Thesis Abstracts
Tracy D. AinsworthPatrick Hulisani Demana
Marion Gray
Kerry James Grundy
Yi He
Lisa Jamieson
Gillian M. Johnson
En-Hui Liu (Grace)
Robert Loeffel
Patricia Mary Mahoney
Dr Marcela Cárdenas Möller
Timothy William Robinson
Katherine Margaret Roy
Ernest Cyril de Run
Jeremy Robert Wales
Elizabeth Ann Woodcock
Thesis Abstract: Immunological Markers for Monitoring the Health of the Tiger Prawn Peneaus monodon
Tracy D. Ainsworth
Abstract of a thesis submitted for the Degree of Master of Science,
James Cook University, Townsville, Queensland, 2003
Prawn aquaculture is a widespread and economically important industry. However, in recent years the industry has been seriously affected by disease. Combating these disease problems through understanding the immune system and monitoring the health of cultured prawns is essential to the sustainability of the industry. This study aimed to investigate immunological markers in the cultured tiger prawn, Penaues monodon. The health condition of prawns is believed to be reflected by the blood cell (haemocyte) population. As such, the primary goal of this study was to produce monoclonal antibodies to haemocytes of P. monodon to provide a tool for studying and marking the penaeid immune system. Haemocytes were collected into anti-coagulant from healthy adult P. monodon via periopod bleeds and prepared as an immunogen of haemocyte lysate. Monoclonal antibodies were produced in balb/c white mice. A panel of six anti-prawn haemocyte monoclonal antibodies was produced, in which three antibody types were identified. Antibody typing was based on immunocytochemistry and immunoblotting. Type one monoclonal antibodies were found to bind to approximately 90% of the cell population, and bound to haemocyte and haemolymph proteins. Type two antibodies were found to be specific to approximately 20% of the population and cells demonstrating characteristics of the large and small granular haemocytes. The third antibody type was found to bind to approximately 80% of the cell population, but the binding pattern of this antibody was unique, staining the nuclear membrane of each cell type. Further immunochemical characterisation of the antibodies was conducted. The cross-reactivity of the antibodies to haemocytes and prawn tissue in situ was investigated. This study aimed to determine immunological links between cell and tissue types. Haemocytes were found to be selectively stained within connective tissue, muscle and gill, and no cross reactivity with these non-haemocyte tissues was found with any of the six monoclonal antibodies. However, some apparently non-freely circulating haemocytes were immunostained with five of the six monoclonal antibodies. Fixed cells, of what appeared to be of a phagocytic nature, were immunostained. Fixed cells were evident in many tissue areas, including the ovary, gill and connective tissue. However, the highest density of immunoreactive fixed cells was found in the heart. These immunostained cells also appeared phagocytic, being large, highly vaculolated cells. An enzyme-linked immunosorbent assay (ELISA) was developed with each of the three antibody types to determine if differences between healthy and diseased cultured P. monodon could be detected. Two experiments using ELISA were conducted. First, healthy P. monodon were inoculated with virus, and ELISA conducted on haemolymph samples of animals three weeks post-inoculation. Significant differences between inoculated and healthy control stock were found with two of the three antibody types. A second experiment, comparing a healthy control stock and a diseased stock from a north Queensland prawn farm was also conducted. Each of the three antibody types was used in ELISA to determine if differences between the diseased stock sampled on two consecutive weeks and the healthy stock could be detected. The diseased farm stock was found to yield significantly different results to the healthy control at the second week of sampling with each of the three antibody types. In conclusion, this study has indicated the potential of anti-prawn haemocyte monoclonal antibodies to provide a means of marking and tracking immunological changes, a method for studying cellular process, haemocytic and cellular disease processes, and finally to further the understanding of the crustacean immune system. This study also proposes haemocyte-specific monoclonal antibodies in ELISA as a novel technique for monitoring haemocyte changes in cultured penaeids. The results from this study demonstrated the potential of the technique, the further development of which has the potential to provide the industry with a mechanism for monitoring cultured penaeids and other crustaceans.
Tracy D. Ainsworth
Centre for Marine Studies
University of Queensland
Brisbane, Queensland 4072
email: t dot ainsworth AT uq dot edu dot au
Thesis Abstract: ISCOMs and Related Colloidal Particles Prepared by the Lipid Film Hydration Method for Antigen Delivery
Patrick Hulisani Demana
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
Purposes: The aims of this thesis were to physicochemically investigate the formation of ISCOM matrices and other types of colloidal particles formed in aqueous dispersion as a function of different mass ratios of Quil A, cholesterol and phospholipid (phosphatidylcholine (PC) or phosphatidylethanolamine (PE)) prepared by the hydration method and to investigate the delivery of subunit vaccines to antigen presenting cells using these colloids.
Methods: The hydration method, recently developed for the preparation of ISCOMs or ISCOM matrices, was used to produce these colloids and other related structures. Factors such as effects of buffer salts, equilibration time and type of phospholipid on the formation of ISCOM matrices and other colloidal particles prepared were investigated. The standard dialysis method for the preparation of ISCOMs was also used for comparison to prepare various colloidal particles. Colloidal particles were characterized by negative staining transmission electron microscopy (TEM). Polarized light microscopy (PLM) was used to identify samples containing cholesterol crystals. Incorporation of a model antigen (modified ovalbumin) into various colloidal particles was investigated by fluorescence spectroscopy following analytical sucrose density gradient ultracentrifugation. Physical properties of solid Quil A-cholesterol-phospholipid formulations (as powder mixtures or compressed to pellets) with or without model antigen were characterized by X-ray powder diffractometry (XRPD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and PLM. Release of model antigen from compressed pellets was investigated in vitro. Flow cytometric analysis (FACS) was used to investigate the in vitro delivery of antigen incorporated into various colloidal structures to murine bone-marrow derived dendritic cells (BMDC).
Results: Pseudo-ternary diagrams revealed that depending on the mass ratio of Quil A, cholesterol and phospholipid, various colloidal particles including ISCOM matrices, liposomes, lipidic/layered structures, ring-like micelles, and worm-like micelles could be identified in the different regions of the diagrams. In the presence of these predominant colloids, helices and lamellae (hexagonal patterns of ring-like micelles) structures were also formed as minor structures. Buffer salts and equilibration time were important factors for the formation of ISCOM matrices and liposomes. The type of phospholipid affected the morphology of ISCOM matrices and lamellae. ISCOM matrices were predominantly found near the phospholipid apex of the pseudo-ternary diagram following sample preparation by the hydration method. On the other hand, samples prepared by the dialysis method produced ISCOM matrices that were predominantly found near the Quil A apex of the pseudo-ternary diagram. No ISCOM matrices could be formed in any binary mixtures prepared by the hydration method in contrast to the dialysis method. Worm-like micelles could only be formed if samples were prepared by the hydration method. An incorporation study demonstrated that the various colloidal particles formed as a result of hydrating phospholipid/cholesterol lipid films with different amounts of Quil A are capable of incorporating antigen, provided it is amphipathic. Freeze-dried lipid powder mixtures were found to contain a lower degree of crystalline cholesterol compared to physically mixed powders. Consequently, physically mixed powders (with or without model antigen) and pellets prepared from the same powders did not spontaneously form ISCOM matrices and related colloidal structures upon hydration as expected from the pseudo-ternary diagram. Release of antigen incorporated into ISCOM particles was relatively slower from the pellets made using freeze-dried powders in contrast to pellets prepared from the physically mixed powders. Using ISCOMs, liposomes and ring-like micelles, it was demonstrated that the model antigen incorporated into these particles could be delivered to dendritic cells leading to activation and proliferation of transgenic T cells. Conclusions: Depending on the mass ratio of Quil A, cholesterol and phospholipid, ISCOM matrices and other types of colloidal structures such as liposomes, lipidic/layered structures, ring-like micelles, lamellae (hexagonal array of ring-like micelles) and worm-like micelles prepared by the hydration method could be identified in the different regions of pseudo-ternary diagram. All the colloids containing Quil A were capable of incorporating an antigen, provided it is amphipathic. Delivery of antigen to DC and immunestimulatory effects of various colloidal particles could be demonstrated.
Dr Patrick Hulisani Demana
School of Pharmacy
University of Otago
Dunedin, New Zealand
email: Pat_demana AT hotmail dot com
Thesis Abstract: The Wellington Region Community Prostate Study
Marion Gray
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
There is a paucity of New Zealand research into prostate disease, yet both benign prostatic hyperplasia and prostate cancer are substantial and increasing public health problems. The maj or aim of the Wellington Region Community Prostate Study (WRCPS) was to define prostate disease in New Zealand and highlight differences between New Zealand's three major ethnic groups; New Zealand European, Maori and Pacific Islands people.
Between January 2000 and February 2002 inclusive, 1,425 eligible subjects were recruited into the WRCPS. Blood samples were taken and questionnaires administered. The WRCPS used immediately available markers of prostate disease; lower urinary tract symptoms and serum Prostate Specific Antigen (PSA) levels, to answer clinical and epidemiological questions in a community-based sample of New Zealand males.
Findings indicated that prostatic diseases are more prevalent than is shown by health statistics, especially for Maori and Pacific Islands men.
The WRCPS addressed clinical prostate disease issues, with respect to enhancing the use of PSA as a diagnostic tool. Findings showed that the ratio of free PSA to total PSA (%fPSA; used to increase the sensitivity and specificity of total PSA as diagnostic test for prostate cancer) was significantly higher in Pacific Islands than New Zealand European men, both groups without symptomatic prostate disease (p < 0.001). Therefore, indicative PSA reference ranges were produced for the three New Zealand ethnic groups.
In addition, demographic and clinical factors (such as use of non-steroidal anti-inflammatory drugs) appear to have a significant effect on levels of PSA and its various molecular derivatives. Finally, PSA levels measured in the laboratory using the Abbott instrument were found to be significantly lower than those measured on the Roche instrument, by an average of 11%.
Enhancing clinical diagnoses is a particularly important step towards the reduction of the internationally high prostate cancer mortality rates faced by New Zealand men. In simple terms, the more accurate the diagnostic tools the more chance clinicians have of curing prostate cancers.
The other major findings elucidated New Zealand-specific and ethnic-specific prostate disease risk factors. In summary, exposure to prostate cancer risk factors was found to differ between ethnic groups, and it would appear from the perspective of ageing, endocrine and environmental factors (such as sexual activity, relationship status, diet, occupation and literacy), that Maori and Pacific Islands men are at increased risk of developing prostate cancer, as well as more rapid disease progression and mortality.
In conclusion; firstly, men's health should be a priority issue for research and health promotion; especially regarding prostatic diseases. Secondly, issues of health inequality faced by Maori and Pacific Islands groups generally, exacerbated by under-reporting in ethnic health statistics, also apply to prostate health. Thus, findings emphasise the importance of actively addressing the prostate health care needs of Maori and Pacific Islands groups, through the formulation of culturally appropriate health policy.
Marion Gray
156 Esplanade, Island Bay
Wellington, New Zealand
Thesis Abstract: The Philosophy of Praxis; A Study of Radical Planning – Past and Future Directions
Kerry James Grundy
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
This thesis is concerned with the theory and practice of planning in Western capitalist societies. Specifically, it examines the tradition of radical planning within the context of conventional planning theory. Its objectives are to evaluate the historical influence of radical planning thought on conventional planning theory and practice, and secondly to assess the relevance of radical planning to contemporary (and future) capitalist societies.
This is accomplished firstly through an analysis of the history of radical planning thought, particularly the theories of a small number of influential planning theorists from the turn of the nineteenth century up until the present. The contemporary relevance of radical planning is examined by critically evaluating Friedmann's theory of transformative planning and by offering an alternative theory based upon a Marxist critique of capitalism and Gramscian transition theory. The normative theory is presented as practice in the form of a critique of the resource management legislation in New Zealand undertaken by the author in the course of his Ph.D. studies. In this way theory is linked to practice and the dialectic between theory and practice made explicit.
The thesis evaluates three propositions:
1. That radical planning thought, although often obscured, possesses a rich
history and has had a profound and lasting influence on modem planning theory
and practice.
2. That radical planning theory has a positive role to play in contemporary
(and future) planning aimed at the transformation of the capitalist mode of
production.
3. That this theory can be applied to a practice of radical planning that can
contribute to a progressive challenge to the dominant capitalist hegemony.
It is concluded that all three propositions can be answered in the affirmative. Radical planning thought does possess a fertile history and has had a significant influence on modem planning theory and practice since its inception at the close of the nineteenth century. Although its existence has gone largely unacknowledged by orthodox planning its presence indicates that historically there has always been resistance to the exploitation of capitalist class society and a search for a better, more sustainable mode of production.
Secondly, radical planning theory can have a positive role in contemporary and future planning. There is a legitimate rationale, founded upon a Marxist critique of capitalism, for adopting a radical approach to planning (a theory for planning). In addition, Gramscian transition theory provides a strong conceptual basis for a theory of radical planning, a methodology of radical planning practice. Lastly, this theory can be applied to a practice of radical planning that may contribute to a progressive challenge to capitalist hegemony. Whether this challenge escalates into fundamental socio-economic change remains to be seen. Radical planners can, however, continue the tradition of earlier proponents of radical change and search for alternatives to the exploitation of human and non-human nature inherent to the capitalist mode of production.
Kerry James Grundy
Senior Environmental Planner
Whangarei District Planner
Private Bag 9023
Whangarei, New Zealand
Thesis Abstract: In Vivo Studies of the Mechanisms of Angiogenesis
Yi He
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
Angiogenesis is seen in many pathological circumstances (e.g. diabetic retinopathy, cardiovascular diseases, rheumatoid arthritis, psoriasis, etc.). Understanding how blood vessels form has become a dominant principal, yet challenging, objective of medical research over the last decade. Development of therapies aimed at inhibiting the growth of new blood vessels is among the most intensively studied approaches in the treatment of cancer. Recently a number of inhibitors of angiogenesis have been discovered and some of them are in clinical trials for treatment of cancer.
Cartilage has been proposed as a possible source of anti-angiogenic material. A number of studies has shown that shark cartilage (SC) exhibits anti-angiogenic activity. This study has shown for the first time that oral consumption of SC inhibits angiogenesis in both the rat mesenteric window model and the rat foetal kidney transplantation model. It indicates that the active principle(s) of SC could survive the digestive system in order to be transported to the site. SC from different processors is examined. Different fractions of SC are also examined. The active components of SC have not been identified. Several lines of evidence have suggested that they are more likely lipids. The mechanisms involved in these anti-angiogenic properties of cartilage extracts are not understood in detail. Several mechanisms of inhibiting angiogenesis by SC have been suggested by this project. VEGF is the essential growth factor for angiogenesis and is sufficient for the formation of new blood vessels if over-expressed in vivo. It is the only mitogen known to act specifically on endothelial cells. This study demonstrated for the first time that oral consumption of SC decreased the transcript level of VEGF in both rat grafted kidneys and adult rat tissues. It has been reported that elevated glutathione (GSH) levels are involved in angiogenesis. This study showed that SC decreased both GSH production and γ-glutamyl cysteine synthetase (γ-GCS), the rate-limiting enzyme in the GSH pathway. Mast cells (MC) have been noted to be involved in pathological or physiological examples of angiogenesis. It was demonstrated that SC inhibited MCs degranulation in the rat mesenteric window model and histamine release in an in vitro model. MCs have been reported to express and produce VEGF, which is found within secretory granules, and many other angiogenic agents like heparin, FGF2, IL-8 and proteases. SC could therefore inhibit the production of these angiogenic agents from MCs by inhibition of MC degranulation.
In conclusion, SC is reported to inhibit angiogenesis in both in vitro and in vivo models. The active component in SC is more likely a lipid, which is able to pass through and be absorbed by the gastro-intestinal tract. Several mechanisms of inhibiting angiogenesis by SC have been suggested in this project, which support the hypothesis that SC acts as a scavenger for reactive oxygen species.
Dr Yi He, Department of Medicine,
Wellington School of Medicine and
Health Sciences,
University of Otago
PO Box 7343, Wellington South
Wellington, New Zealand
email: mikeyihe AT hotmail dot com
Thesis Abstract: Oral Health Disparities among Pacific and New Zealand Children
Lisa Jamieson
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
The investigations described in this thesis involve studies of children anecdotally described as being dentally disadvantaged, whether by virtue of their ethnic status or their location. The findings do not always support that anecdotal evidence, and, as such, are valuable contributions to the limited dental health information available for these groups.
The dental experience of children living in the Pacific is recognised as having deteriorated in the last two decades. All prior oral health investigations in this area have been cross-sectional in design, lacking the suitable time-ordering which would enable caries risk factors to be identified. In this study of Fijian children, a longitudinal approach was used, and it was found that frequency of snack consumption and not having visited a dentist were predictors of future caries experience. Snack consumption and dental check-ups are fundamentally the responsibility of care-givers, indicating the important role these people have in influencing child dental health in Fiji. It may be beneficial for Fijian health policy makers to consider this when organising oral health promotion and education initiatives.
There has been much change in the ethnic make-up of the New Zealand population in recent times. The proportion of Pacific people in the population is now considerable, and continues to increase. Pacific people in New Zealand are recognised as having poor general health (and dental health) and difficulties in accessing health care services. In analyses of dental data from the National Child Nutrition Survey, Pacific children were found to be more likely than their non-Pacific counterparts to have not visited a dentist, to have not received a filling, or to have had had a tooth extracted because of decay. The dental health needs of this group will probably increase in future, making them a considerable burden on an already stretched dental health service. It seems that providing incentives to encourage School Dental Service enrolment of Pacific children, increasing the number of Pacific personnel in dental training, and creating a more culturally sensitive dental profession may improve the accessibility of dental services to this group, which, in turn, may encourage improved oral health.
Validity is an important aspect of items used in self-report health studies, and it refers to the extent to which items measure what they purport to measure. The National Child Nutrition Survey was a study of 5-14-year-old children's nutrition in New Zealand, and included a number of self-report dental items. In order to give the dental findings greater meaning, a validation study was conducted to determine whether child self-report measures were a valid indicator of clinical oral health. The dental items appeared to be clinically valid, and showed a high level of concordance between child and care-giver. The findings suggest that using self-report measures may be valuable in future dental epidemiological investigations of children where resource constraints preclude clinical examinations or caregiver involvement.
There is a paucity of oral health information on children living in remote communities in New Zealand. Evidence from other countries, however, suggests that living remotely is associated with lower access to dental services, and poor oral health. Children residing in the Chatham Islands (the most remote area of New Zealand) were found to have comparable oral health status to their counterparts in an urban New Zealand setting. This was most likely due to Chatham Islands children taking part in regular School Dental Service visits, and having similar access to cariogenic food and beverage products as urban children. This trend may change, however, as the dental therapist is no longer a resident of the Chatham Islands, and is therefore unable to treat children's dental needs as they arise on a day-to-day basis.
The findings presented in the thesis may be useful for dental policy-makers in the Pacific and New Zealand, who both face increasing constraints for health resources. It is hoped the findings also enable more effective distribution of oral health resources, and encourage initiatives that promote appropriate training of dental health personnel.
Lisa Jamieson
Australian Research Centre for Population
Oral Health,
The University of Adelaide,
Australia 5005
email: lisa dot jamieson AT adelaide dot edu dot au
Thesis Abstract: The Human Ligamentum Ncuhae and Related Ligaments
Gillian M. Johnson
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
The aim of this study was to clarify the anatomy of the human ligamentum nuchae and to determine if nerve endings terminated within its connective tissue structure. Gross anatomical investigation and the microscopic study of plastinated epoxy-resin slices were carried out in preference to a histological study. The combined results indicate that, as with the supraspinous and interspinous ligaments of the thoracolumbar spine, the muscle aponeuroses make the major contribution to the dense connective tissue structure of the human ligamentum nuchae. The study of serial epoxy-resin slices reveals regional differences within the connective tissue fiber orientation which are directly attributable to the arrangement of muscle attachments along its length. In terms of its nerve supply a qualitative investigation has shown that small nerve endings may be found in close proximity to blood vessels in the connective tissue of the human ligamentum nuchae at least as early as nineteen weeks of fetal development. Quantitatively, the preliminary evidence from a small area of ligamentum nuchae sampled in a human fetus indicates that the nerve endings may not be uniformly distributed throughout the ligamentum nuchae during development. Using the brush-tailed possum (Trichosurus vulpecula) as an experimental model for the human cervical spine, an acetylcholinesterase nerve staining method was adapted and trialed for thick epoxy-resin slices. This latter approach proved to be less effective than immunocytochemistry in identifying nerves within the connective tissue of the ligamentum nuchae. Functionally, the regional differences in the connective tissue organization of the ligamentum nuchae along the length of the cervical spine and the well-defined attachments onto the C6 and C7 spinous processes suggest that the LN is designed to support the posterior elements within the lower cervical spine. In this light, it is argued that the role of the ligamentum nuchae may best be considered within the context of the human head and neck musculature rather than a diminished form of the animal ligamentous structure. However, whether or not the subtle differences in the distribution of nerve fibers within the fetal ligamentum nuchae is reflective of regional differences within the connective tissue of the adult structure is yet to be determined.
Gillian M. Johnson
School of Physiotherapy,
University of Otago,
PO Box 56, Dunedin
New Zealand
Thesis Abstract: The Microstructures and Stability of Emulsions
En-Hui Liu (Grace)
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
Emulsions are utilised in a wide range of biological and commercial environments. In their simplest form they are a dispersion of one liquid in another in the presence of emulsifiers. One of the simplest types of emulsifier is a surfactant. Surfactants are molecules which consist of two very different regions. One part is polar (head group) and the other is non-polar (tail group). The polar part associates with the more polar phase of the emulsion (water), while the non-polar part interacts with the less polar phase (oil). An input of energy is necessary to form the kinetically stablised emulsions. In this thesis, triton X-100 was used as the surfactant and three systems were studied: toluene/tritonX-100/water, octane/triton X-100 and tetradecane/triton X-100/water. Six techniques were used to probe the microstructures of the stabilised emulsions: PGSE-NMR, rheology, freeze-fracture transmission electron microscopy, creaming rate, conductivity and laser diffraction particle sizing.
Stable emulsions in the ternary toluene/triton X-100/water system can be prepared for a surfactant to oil weight ratio of 1:5. Emulsions are formed on continuum between 0.5 and 14 wt% triton X-100. For all triton X-100 wt% an oil-in-water emulsion is formed. At high triton X-100 concentrations a closed-cell fluid foam is stabilised. In addition, a bicontinuous emulsion can be stabilised for several hours for a triton X-100 composition of 6 wt%. This phase coexists with an oil-in-water emulsion. The bicontinuous phase is formed only when the input energy is minimised, for higher input energy no stable bicontinuous emulsion could be prepared. Moreover, the bicontinuous emulsion is extremely sensitive to external stimuli.
Coalescence and rupture of the oil droplets in the dispersed droplet emulsions occurs on a time scale faster than the PGSE NMR experiments (∼ 200 ms) in toluene system. Microstructure tortuosity in addition to obstruction and/or hydration effects dominate the system at high oil content. The stability of the closed-cell foam emulsions is significantly greater than the droplet oil-in-water emulsions.
The series of oil-in-water emulsions, formed in the toluene/triton X-100/water system were further investigated by varying the energy input during the formulation process. Emulsion microstructure could generally be altered, for a single emulsion composition, by changing the amount of energy supplied during emulsification. The response of each of the different microstructures formed at a single chemical composition on application of a controlled shear; was also examined.
For high-oil content droplet phases, emulsion microstructure is markedly altered on increasing energy input. However, all high-oil content droplet microstructures respond identically to the application of a controlled external stress. This indicates that the systems collapse under shear and yield a single common microstructure. Hence, the strength of the interfacial domain of these emulsions, controlled primarily by the triton X-100, is extremely weak. In contrast, low-oil fraction droplet phases maintained the integrity of their microstructure before and after application of a controlled shear when low formulation energies were used during initial processing. However, at higher formulation energies, microstructures again collapsed as evidenced from a single shear response. The bicontinuous emulsion microstructure is extremely sensitive to energy input and cannot be realised at high-input energy. The microstructure of the closed-cell foam emulsion is almost completely independent of formulation energy and remains stable upon subsequent application of shear.
On changing the oil from toluene to either octane or tetradecane it was observed that no stable emulsions could be prepared for formulation energies below approximately 2600 J and additionally stable emulsions could only be formed for triton X-100 concentrations between 8 and 12 wt%. As for the toluene system, water is always the continuous phase. The oil domains in these two systems do not undergo the rapid and constant coalescence and rupture that occurs in the toluene system. Instead they collide, interact and then separate. In the octane system both unrestricted and restricted diffusion of the oil droplets occurred. Using this information a characteristic spacing between the droplets of 0.2 to 0.4 μm was measured. In the tetradecane system, the droplets undergo restricted diffusion only for the measurement times used.
The stability of the emulsions prepared with octane and tetradecane was signigicantly enhanced and this was seen to increase as the chain length of the oil was increased. Ostwald ripening is found to occur in all three systems.
En-Hui Liu (Grace)
Department of Chemistry,
University of Otago, New Zealand
email: gliu1113 AT hotmail dot com
Thesis Abstract: Sippenhaft in the Third Reich: analysing the `spectre' of family liability punishment against opposition in Nazi Germany 1933--1945
Robert Loeffel
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of New South Wales, Australia, 2004
This thesis examined the phenomenon of Sippenhaft, the punishing of family members for the crime of a relative. This assessment was restricted to investigating the incidence of Sippenhaft against those considered by the Nazis to be "German" (Reichsdeutsche) or "of German blood" (Volksdeutsche) The infliction of punishment regardless of the innocence or guilt of the individual determines that, practically applied, this policy must be considered a device of terror. Specifically, instances of Sippenhaft against civil Germany within the military and against particular resistance groups were investigated.
It was against the external Soviet sponsored `National Committee for a Free Germany" (NKFD) and "League of German Officers" (BDO) resistance groups and in particular after the assassination attempt on Hitler on 20 July 1944 that Sippenhaft came closest to becoming a practical reality. Assessing the manifestation of Sippenhaft involved assessing the dissemination of orders and directives from above as well as how these were, or were not, put into practice. It also relied on establishing an understanding of how Sippenhaft was practically applied against families. This involved contacting numerous family members connected to various German Resistance groups, both within the 20 July coup attempt and the NKFD and BDO resistance groups, to determine if they were placed under arrest in accordance with family liability. Their stories of arrest and imprisonment reveal how this terror became a reality. These individuals ranged from siblings, wives and parents to young children. Many of these children were arrested and housed in a specially created Sippenhaft "children's home".
As a result, this thesis is focused to a degree in the period following 20 July 1944, when the practical application of Sippenhaft was mostly achieved and adds further to the awareness of the radicalisation of the Third Reich in the closing stages of the war. The investigation into this period after 20 July revealed that while many of the families connected to the German Resistance were punished, within the military in general, despite the widespread and open threat, Sippenhaft was not practically applied. Similarly, threats made against the German public were seldom followed up with actual arrests. In other words, within these two domains in Nazi Germany, Sippenhaft was never practically applied with any regularity. Consequently, this thesis offers a deeper comprehension of the potency of fear over practice, as a means of social coercion and how this was practically achieved. Rather than being used as an unconstrained device of terror, Sippenhaft was largely restricted in its extent and capacity. How effectively these fears were created and sustained are the main focus of this thesis.
Dr Robert Loeffel
School of History
University of New South Wales
Kensington NSW 2052
email: r dot loeffel AT unsw dot edu dot au
Thesis Abstract: Mast Cells and Microflora in the Possum cul-de-sac
Patricia Mary Mahoney
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
Keywords: possum, reproduction, mast cells, cul-de-sac, stereology
Mast cells are a common feature of the vaginal cul-de-sac of female brushtail possums. In the reproductive organs of other mammals empirical studies have found that mast cell numbers change at different stages of the reproductive cycle. The reason for the presence of mast cells in the cul-de-sac is unknown but may reflect microbial presence as mast cells are typically associated with biological responses to parasitic and/or bacterial invasion in gut and pulmonary tissues. Alternatively, it may indicate a role for mast cells in marsupial reproduction.
This study will attempt to address the significance of mast cells in the cul-de-sac of the brushtail possum with the hypothesis: "That mast cells in the vaginal cul-de-sac of the brushtail possum undergo numerical, spatial and morphological changes during different reproductive states." This investigation will assess whether the changes are due to microbial invasion or reproductive processes.
Cul-de-sac tissues were collected aseptically for microbiological, stereological and TEM analyses, from female adult possums (n = 6/group) that were lactationally anoestrous or in the follicular or luteal phases of the oestrous cycle, where oestrous cyclicity was induced by the removal of pouch young and reproductive status confirmed by laparoscopy. A similar analysis was undertaken on untreated seasonally anoestrous animals and those treated with subcutaneous implants of oestradiol 17β (n = 6/group) as well as juvenile animals (n = 5). Microbial populations were quantified and bacteria identified by media-culture and gram staining. The fractionator and optical disector stereological methods were used to quantify mast cell populations in both the epithelial and connective tissue components of the cul-de-sac.
Microflora were present at very low levels (<5 x 105 organisms g-1) in the culs-des-sacs from all reproductive groups and were undetectable in 15/41 animals. The total number of mast cells present was significantly greater in adult than in juvenile animals. Amongst adult groups, mast cell numbers were greater in follicular and luteal phase animals than in oestradiol-treated animals. Changes in total mast cell number amongst adult animals were not reflected in changes to the number of epithelial mast cells. Mast cell populations displayed two aspects of anisotropy irrespective of reproductive status, where (i) cells were predominantly located in the epithelial tissue and/or in that region of connective tissue adjacent to the basement membrane and (ii) cells often appeared as aggregations of three or more cells per disector volume.
Mast cell density was significantly lower in those animals exposed to endogenous and exogenous oestradiol than in lactationally and seasonally anoestrous animals. This may be attributed to increases in total cul-de-sac volume. Electron microscope studies showed that the volume fraction (Vv) of granules in mast cells was greater in lactationally and seasonally anoestrous animals than in luteal phase animals.
In conclusion, the density of mast cells in the cul-de-sac of the female brushtail possum shows changes after exposure to oestradiol. This was not related to microbial invasion, but may be due to changes in tissue volume, or to some unidentified stimulus.
Patricia Mary Mahoney
Department of Anatomy and Structural
Biology,
School of Medical Sciences,
University of Otago
PO Box 913 Dundein, New Zealand
email: trish dot mahoney AT stonebow dot otago dot ac dot nz
Thesis Abstract: Investigation of a Decision-support Framework for the Sustainable Development of the South American Quarrying Industry: An Application of the Quadruple Bottom Line
Dr Marcela Cárdenas Möller
Abstract of a thesis submitted for the Degree Doctor of Philosophy,
University of New South Wales, New South Wales, 2004
This research examines the connection between the implementation of strategies addressing the environmental, social, economic and governance aspects of mining (what the author recognises as the quadruple bottom line of sustainable development) and the sustainability of the South American quarrying industry.
The project included the analysis of the quarrying industry of the capital cities of Colombia, Chile and Ecuador, as representative case studies of South America. Fieldwork in these cities involved interviewing stakeholders, visiting quarries, observing behaviour, and testing knowledge and understanding about sustainable quarry development. The information gathered was then combined with the information provided by national mining registers to identify the issues that inhibit the sustainability of quarrying in Colombia, Chile and Ecuador.
In parallel to the fieldwork, an analysis was conducted of specific environmental, social, economic and governance aspects of the minerals industries of various countries. These countries included Canada, the United States, Panama, Dominican Republic, Cuba, Brazil, Spain, England, South Africa, Australia, China and the Philippines. This investigation confirmed the connection between the implementation of strategies addressing the quadruple bottom line of sustainable development and the sustainability of the minerals industry.
A combination of three qualitative analysis methods namely, successive approximation, illustrative method and ideal types method, has been used in the development of specific sustainable development strategies for the South American quarrying industry. These strategies are presented as the "decision-support framework for the sustainable development of the quarrying industry of South America". This framework focuses on the implementation of strategies dealing with the quadruple bottom line of sustainable development. The key areas addressed in these strategies are: a regulatory framework for quarrying, special considerations for the small-scale and artisanal quarrying industry; environmental strategies for larger quarrying companies; the role of the quarrying industry's stakeholders; and additional environmental recommendations.
The research undertaken for this thesis was able to fill significant knowledge gaps about the unsustainable character of the South American quarrying industry. It was found that the key sustainability issues faced by the South American quarrying industry are: the marginal and undercapitalised character of this industry; the weaknesses of the regulatory framework for quarrying, the environmental and social impacts of quarrying operations; and the effects of quarrying in urban areas. Corruption and armed conflict were also found to be important limitations of the industry. It was confirmed that the South American quarrying industry is not based on a framework that reflects the consideration of the quadruple bottom line of sustainable development.
The thesis concluded that the quarrying industry of South America is not ready to achieve its sustainable development and to contribute to the sustainability of other economic activities of these countries. Further research, particularly in relation to small-scale and artisanal quarrying operations; implementation of cleaner production and eco-efficiency in quarrying; recycling and reuse of quarry resources; and quarry development in urban areas is recommended.
Dr Marcela Cárdenas Möller
Sustainable Mining Research Group
University of New South Wales
email: m dot cardenas AT student dot unsw dot edu dot au or
marcecardenas AT hotmail dot com
Thesis Abstract: Near Infrared Spectroscopy of Aromatic Molecules
Timothy William Robinson
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in interstellar space, and are currently the best candidates for the carriers of the so-called unidentified infrared emission bands observed from many astronomical sources. Despite extensive investigation of the infrared spectral properties of PAHs, both from experimental study and quantum chemical calculations, a definitive assignment of the emission bands to specific PAHs has remained elusive.
Near-infrared spectroscopy is a technique that is very sensitive to subtle effects of molecular structure such as small differences in CH bond lengths. Near-infrared spectra are dominated by vibrational overtone transitions that correspond to localized CH-, NH-, or OH-stretching oscillators in the molecule. We have suggested that an analysis of the near-infrared spectroscopy of PAHs could provide better resolution and aid the identification of specific PAHs in interstellar and terrestrial environments.
We have calculated the fundamental and overtone CH-stretching spectra of small PAH molecules in their neutral, cationic, and anionic states. The calculations use an anharmonic oscillator local mode model with local mode parameters and dipole moment functions determined from ab initio and density functional calculations. The PAH cations are characterized by blue-shifted CH-stretching transitions which show dramatically decreased fundamental intensity compared to the neutral molecules. The anions are characterized by red-shifted frequencies and an enhancement of fundamental intensity. In contrast to the fundamental region, the overtone intensities are predicted to be remarkably similar for the neutral and charged species. The larger than expected overtone intensities for the cations should provide new impetus for experimental studies and perhaps provide a means for the first observation of CH-stretching transitions in PAH cations.
The low vapour pressures of PAHs makes experimental vapour-phase studies difficult. We calculated the vibrational spectra of the aromatic molecules phenol, aniline, and aminophenol, and measured the vibrational spectrum of phenol to 17,000 cm-1 with the use of conventional and laser photoacoustic spectroscopies. The calculated frequencies and intensities are compared to our experimental vapour-phase spectra of phenol, and spectra of the molecules under jet-cooled conditions obtained from Prof. M. Fujii's laboratory. We find that our simple local mode model can provide spectroscopically accurate absolute and relative vibrational intensities, and performs equally well for OH, NH, and CH oscillators.
The recent observation of low-lying electronic transitions in PAH cations has demonstrated that electronic transitions need to be considered to complement our work on vibrational overtone excitation. We have tested the ability of current theoretical methods to calculate electronic transitions accurately. The results from these studies showed that the multireference configuration interaction method can provide quantitatively accurate excitation energies and oscillator strengths, whereas the configuration-singles and time-dependent density functional methods do not provide consistently accurate predictions.
Timothy William Robinson
Department of Chemistry
University of Otago
PO Box 56, Dunedin
New Zealand
email: timr AT alkali dot otago dot ac dot nz
Thesis Abstract: Powerfully Affected by the Foreign Tongue Language in the Works of Emine Sevgi Özdamar
Katherine Margaret Roy
Abstract of a thesis submitted for the Degree Master of Arts,
University of Otago, New Zealand
Born in Turkey and living and writing in Germany, Emine Sevgi Özdamar is an author who writes between the two cultures. This thesis examines the language of her works — the novels Das Leben ist eine Karawanserei hat zwei Türen aus einer kam ich rein aus der anderen ging ich raus and Die Briicke vom Goldenen Horn, the collections of Erzählungen, Mutterzunge and Der Hof im Spiegel, and the play "Keloglan in Alamania". It analyses the contribution of this language to the creation of a "new" identity, the voicing of a hybrid German-Turkishness.
The thesis, divided into three chapters, begins with an introduction of the background against which Özdamar is writing, and includes a discussion of the appropriateness of the application of Deleuze and Guattari's theory of "minor literature" and post-colonial literary theory for a reading of Özdamar's work. In Chapter One, Özdamar's first novel, Karawanserei, is then made the focus of a discussion of the linguistic techniques employed to construct difference, "re-place" German and restore the balance between centre and the perceived "fringe". Chapter Two examines the second novel, Brücke, written in what is initially perceived as a more "standard" German. Here the focus shifts to the language of narrative itself, in particular its role in structuring the novel, and the result of a Deleuzian-style "affect" on the reader: how it communicates the narrator herself and her environment to the reader. This chapter begins with an assessment of the initial reception of this work, concluding that it defies the German genre-categorisation many of the reviewers sought to apply. The third section of the thesis focuses on the author's own journey to hybridity through language, beginning with her discussion of the loss of her mother tongue ("Mutterzunge") and her attempt to regain it by going back to the Turkish language's Arabic roots ("Großvaterzunge"). This going back sparks a leap forward and we encounter several hybrid texts (such as "Karriere einer Putzfrau" and "Keloglan in Alamania"). The collection Der Hof im Spiegel highlights the division of Germany itself, provides a new take on the centre fringe relationship, and details the fact that the Turks are now staying ("Die neuen Friedhöfe in Deutschland").
It is this Turkish minority in Germany for whom Özdamar provides a voice, creating a new style of German-language literature in extending its boundaries and expressing an "interior". Özdamar's work resists marginalisation, demanding thoughtful reading. Narrative structure, idiom and syntax are all other than the norm of standard German, and the resultant narrative style re-writes the language of the centre. Through language, a new becoming-identity is conveyed.
Katherine Margaret Roy
Rapid Number 163
Gladstone Road
East Taieri, Dunedin
New Zealand
email: kateroy AT clear dot net dot nz
Thesis Abstract: Unintended Effects of Ethnically Targeted Advertising
Ernest Cyril de Run
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
Although advertising has been a major area of study in marketing, research investigating the unintended effects of targeted advertising beyond social and moral issues has been limited. This thesis contributes to the current body of knowledge by examining the unintended effects of ethnically targeted advertising on ethnic groups that are not targeted, but who are still likely to see the advertising. The thesis also develops a holistic model for measuring the effects of targeted advertising using four variables: emotions, attitude to the advertisement, attitude to the company and behavioural intentions. The conceptual basis of the model is accommodation theory, which allows for different levels of targeting based on the language mix used in advertisements (e.g. ranging from advertisements that are solely in the targeted group language to advertisements with a mixture of languages to advertisements that are solely in the non-targeted group's language). The model was tested on three different ethnic groups in Malaysia.
Five key propositions were tested during the research:
1. That targeted advertisements will elicit negative unintended
reactions from ethnic groups that are not targeted (P1);
2. That there will be
a direct relationship between the strength of reactions and the degree of
language accommodation (i.e. those not targeted will have stronger negative
reactions to advertisements that accommodate the targeted ethnic group) (P2);
3. That "novel" advertisements with unexpected combinations of language and
cultural cues, will elicit more negative reactions from those not targeted
rather than "standard" advertisements with more commonly used combinations of
language and cultural cues (P3);
4. That there will be significant differences
within ethnic groups in their reactions to targeted advertisements (P4);
5. That there will be significant differences between ethnic groups in their
reactions to targeted advertisements (P5).
A factorial design was used to analyse the data collected by a survey. The factorial design consisted of five different advertisement types (by language), three different ethnicities, ethnic identification strength and measures of social distance. The dependent variables used were attitude towards the company, corporate credibility, corporate image, rapport, attitude towards the advertisement, affective response towards the advertisement, attitude towards the product, attitude towards the brand, purchase intention, word of mouth, overall emotions, alienation, anger, feeling targeted and perceived threat.
Test for P1 supported the proposition of negative responses by non-targeted ethnic groups, albeit that a lot of these were affective responses. The findings also suggested that ethnic dominance and the social and cultural context might have mediated the level of negative response. Test for P2 showed that the strength of negative reactions was not necessarily directly linked to the level of language accommodation. Test for P3 showed that `novel' advertisements created stronger negative reactions among non-targeted ethnic groups than 'standard' advertisements. Test for P4 showed that within-group effects were minimal. The interactions posited for P5 did not occur.
The theoretical implications of this thesis include support for a `holistic' approach to targeted advertising. In other words, instead of the previous view that looked at targeting as the end product, the thesis suggests that there are more factors to consider after targeting is implemented. The thesis also develops a model for assessing the unintended reactions of those not targeted. The findings indicate that there are limits to Accommodation Theory, Distinctiveness Theory and the concept of cultural schema. This research also has managerial implications and identifies actions that can be taken to reduce the negative reactions of non-targeted ethnic groups to ethnically targeted advertising and towards the company itself.
Dr Ernest C. de Run
Fakulti Ekonomi dan Perniagaan
Universiti Malaysia Sarawak
94300 Kota Samarahan
Sarawak, Malaysia
email: drernest AT feb dot unimas dot my
Thesis Abstract: Improving the Immunogenicity of Influenza Subunit Antigens through the use of Antigen Delivery Systems and other Immune Modulators
Jeremy Robert Wales
Abstract of a thesis submitted for the Degree of Doctor of Philosophy,
University of Otago, New Zealand, 2004
Subunit antigen vaccines, based on one or more epitopes, offer advantages over whole organism vaccines in terms of safety and purity. However, these vaccines are often less immunogenic. To increase their immunogenicity, specific signalling molecules and particulate delivery systems have come under scrutiny. This study investigated methods to improve the immune response to two Influenza haemagglutinin-derived subunit antigens, consisting of a T and B cell epitope (TB), or three T cell epitopes (TTT).
Through recombinant technologies, Interleukin-2 (IL-2) was fused to these subunit antigens. In vitro, the fusion of IL-2 to antigen was shown to increase the activation of an antigen specific T cell hybridoma induced by the subunit antigens. The use of IL-2Rβ antibody to block the receptor subunit on macrophages reduced the activity of the subunit IL-2 fusion protein, but not the subunit antigen alone. These results, amongst others, suggest that the adjuvancy exerted by IL-2 in our in vitro system was due, at least in part, to an IL-2Rβ mediated uptake mechanism rather than its T cell growth factor activity.
Encapsulation of the subunit antigens in liposomes also increased their antigenicity, although the response to subunit antigen IL-2 fusion proteins was not improved when encapsulated. This may be due to high doses of antigen being delivered to antigen presenting cells, through liposomal encapsulation, negating any affect that the IL-2Rβ uptake pathway may be able to confer.
In vivo, splenocytes from mice vaccinated with antigen-IL-2 fusion proteins in liposomes produced significantly higher levels of IFN-&gamm; than splenocytes from mice immunised with antigen alone either delivered in solution or in liposomes, or antigen-IL2 delivered in solution. TB-IL2 delivered in liposomes was also able to induce significant levels of IgG1 reactive to the Influenza virus (p < 0.05). This work suggests that fusing antigen to IL-2 and delivering this within a particulate system enhances the immune response to a peptide antigen. However, the combination of these systems was unable to induce a sufficient immune response to comprehensively protect animals against influenza.
Therefore, other immune stimulators were examined. NF-κB inducing kinase (NIK) is an intracellular signalling molecule involved in the signalling pathway upstream of NF-κB. Plasmid-based delivery on its own is not considered to be an effective adjuvant, as it is inefficient at penetrating the cell/nuclear membrane. A potential DNA delivery system is polyethylenimine (PEI), which is a cationic polymer that is able to bind DNA and actively traffic plasmids to cell nuclei.
The pNIKG1:PEI complex was able to increase T cell activation in vitro induced by pre-activated macrophages presenting Influenza viral peptides. In vivo, pNIKG1:PEI complexes were shown to increase specific lymphocyte proliferation and IFN-γ production (p < 0.05) when used as an adjuvant with TB-IL2 delivered in liposomes. However, the addition of pNIKG1:PEI was not able to sufficiently improve the immune response to comprehensively protect animals against influenza.
These results contribute to our knowledge of the use of signalling molecules and particulate delivery. Through a better understanding of these systems, safe and effective vaccines may be developed from subunit antigens in the future.
Jeremy Robert Wales
Imunology Research Laboratory
Department of Microbiology and Imunology
University of Otago
Dunedin, New Zealand
Thesis Abstract: Effects of Environmental Enrichment on Fundamental Cognitive Processes in Rats and Humans
Elizabeth Ann Woodcock
Abstract of a thesis submitted for the Degree Doctor of Philosophy,
University of New South Wales, New South Wales, 2004
This thesis examined whether it is possible to enhance core elements of the information processing system with specific forms of environmental stimulation. The first series of experiments demonstrated that a preweaning environmental enrichment procedure that provided 60 minutes of daily multisensory stimulation accelerated the development of long-term contextual memory and enhanced inhibitory processing in young rats. That is, whilst stimulated and non-stimulated rats exhibited long-term memory of a context at 26 days of age, only stimulated rats showed this ability at 18 days of age. In addition, stimulated rats showed a faster rate of extinction of long-term contextual memory at 21 days of age, which was taken as evidence of enhanced inhibitory learning (i.e., context - no US) in these rats.
Subsequent experiments with adult rats demonstrated that a combination of preweaning multisensory stimulation and postweaning rearing in an enriched environment improved the (1) specificity of long-term contextual memory, (2) speed of contextual information processing, and (3) availability of attentional resources. More specifically, enriched-reared rats demonstrated superior ability to discriminate between two similar contexts in comparison to standard-reared rats. In addition, enriched-reared rats showed superior memory of a context when there was limited time available to form a memory of that context. This finding was taken to indicate that rats that receive environmental enrichment are able to process contextual information more rapidly. Finally, standard-, but not enriched- reared rats showed less conditioning to a discrete stimulus when it was presented in combination with a stronger stimulus during training compared to when it was presented by itself. The finding that enriched-reared rats did not show this overshadowing effect suggests that these rats have greater availability of attentional resources to divide between two stimuli that are competing for attention.
The experiments with rats were followed by two experiments with children that investigated the effects of a computerised cognitive training procedure on information-processing speed. These experiments demonstrated that 30-minutes per weekday of training in rapid decision-making for three to five weeks improved children's performance on two tests of processing speed (i.e., a choice reaction time and odd-man-out task). In addition, the speeded training improved children's ability to sustain their attention and inhibit impulsive responses on a continuous performance test (Test of Variables of Attention). The cognitive training procedure had no effect on children's performance on a measure of fluid intelligence (Raven's Standard Progressive Matrices).
The results of the experiments reported in this thesis suggest that a number of fundamental cognitive processes can be modified by environmental conditions that place increasing demands on the information-processing system. A neurobiological model, focusing on myelin, axon diameter, and the glutamatergic, glucocorticoid, noradrenergic, and cholinergic systems, was proposed in order to explain the observed effects of environmental stimulation on cognition in children and rats.
The rationale for attempting to enhance fundamental cognitive processes was that improving these processes should ultimately improve general intellectual functioning. With respect to this aim, the correlational data from the present experiments with children revealed promising trends towards greater improvements in the tests of fundamental cognitive processes in those children in the training group with slower processing speed at the start of the intervention. This finding suggests that cognitive training may be even more effective at enhancing processing speed and other fundamental cognitive processes in children with intellectual impairments, who reportedly have slower processing speed than normal children. However, the extent to which training-related improvements in fundamental cognitive processes generalise to improvements in general cognitive functioning is unclear. That is, there is insufficient evidence that processing speed and other fundamental cognitive processes are causally related to intelligence. It is therefore essential that future cognitive training research is mindful of related developments within the intelligence and information processing literature.
Dr Elizabeth A. Woodcock
University of New South Wales,
Sydney, NSW 2062
Australia
email: e dot woodcock AT unsw dot edu dot au