Measuring miscible fluid displacement in porous media with magnetic resonance imaging

The development of new quantitative magnetic resonance imaging (MRI) technologies open new opportunities for measurements of mass transport in porous media. The current work examines a simple miscible displacement process of H2O and D2O in porous media samples. Laboratory measurements of dispersion in porous media traditionally monitor the effluent intensity of an injected tracer. We employ MRI to obtain quantitative water saturation profiles, and to measure dispersion in rock core plugs. The saturation profiles are modeled with PHREEQC, a fluid transport modeling program. We demonstrate how independent magnetic resonance measurements can be employed to estimate three important input parameters for PHREEQC, mobile porosity, immobile porosity, and dispersivity. Bulk Carr Purcell Meiboom Gill (CPMG) T2 distribution measurements were undertaken to estimate mobile and immobile porosity. Bulk alternating-pulsed-gradient-stimulated-echo (APGSTE) measurements were undertaken to measure dispersivity. The imaging method employed, T2 mapping Spin Echo Single Point Imaging (SE-SPI), also provides information about the pore size distributions in the rock cores, and how the fluid occupancy of the pores changes during the displacement process.

Efficacy of progressive aquatic resistance training for tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis: a randomised controlled trial

OBJECTIVE: To study the efficacy of aquatic resistance training on biochemical composition of tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis (OA).

DESIGN: Eighty seven volunteer postmenopausal women, aged 60-68 years, with mild knee OA (Kellgren-Lawrence grades I/II and knee pain) were recruited and randomly assigned to an intervention (n = 43) and control (n = 44) group. The intervention group participated in 48 supervised aquatic resistance training sessions over 16 weeks while the control group maintained usual level of physical activity. The biochemical composition of the medial and lateral tibiofemoral cartilage was estimated using single-slice transverse relaxation time (T2) mapping and delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC index). Secondary outcomes were cardiorespiratory fitness, isometric knee extension and flexion force and knee injury and OA outcome (KOOS) questionnaire.

RESULTS: After 4-months aquatic training, there was a significant decrease in both T2 -1.2 ms (95% confidence interval (CI): -2.3 to -0.1, P = 0.021) and dGEMRIC index -23 ms (-43 to -3, P = 0.016) in the training group compared to controls in the full thickness posterior region of interest (ROI) of the medial femoral cartilage. Cardiorespiratory fitness significantly improved in the intervention group by 9.8% (P = 0.010).

CONCLUSIONS: Our results suggest that, in postmenopausal women with mild knee OA, the integrity of the collagen-interstitial water environment (T2) of the tibiofemoral cartilage may be responsive to low shear and compressive forces during aquatic resistance training. More research is required to understand the exact nature of acute responses in dGEMRIC index to this type of loading. Further, aquatic resistance training improves cardiorespiratory fitness.

Mapping land use in a large agricultural basin : a comparison between classification techniques

In order to facilitate the better management of river basin resources, the Glenelg-Hopkins region in south-east Australia required an accurate and up to date land use map. Land use has a major impact on Australia's natural resources including its soil, water, flora and fauna and plays a major role in determining basin health. Inappropriate land use and practices have contributed to extensive dryland salinity and water quality problems. Land use data is often required for environmental models and in most cases the reliability of model outputs is dependent on the spatial detail and accuracy of the land use mapping. This paper examines methods to obtain an up to date land use map and a detailed accuracy assessment using Landsat ETM+ data for a regional basin. A multi-source based approach allowed the collection of 4817 ground truth data points from the field investigation. This enabled researchers to (i) incorporate a full range of information into digital image analysis with significant improvements in accuracy and (ii) hold sufficient independent references for an accurate error assessment. Classification accuracy was significantly improved using a stratification design, in which the region is sub-divided into smaller homogenous areas as opposed to a full scene classification technique. The overall classification accuracy was 84% (KHAT= 0.833) for the stratified approach compared to 76% (KHAT= 0.743) for the full scene classification. Effective assessment, planning and management of basins are dependent on a sound knowledge of the distribution and variability of land use.

From local to national: aspects of mapping the welfare third sector in Australia

The paper charts the authors' research experiences in various types of sociological mapping ofc ommunity or third sector organisations. Specifically this was a search for a way of understanding how third sector organisations dealing with welfare issues were operating in Australia in the mid I990s.

The paper tells the story of how the researchers worked through the implications of being faced initially with a dearth of information about their subject and of how lessons were learnt about the disjunctions between what is formally given as textbook knowledge about research practice and what actually can and does happen: that is, the relationship between the theory and the practice of research.

In discussing the creation of a database of organisations, conducting focus groups and a national sample survey, the paper comments on some of the practical problems facing third sector researchers as well as looking at concept generation and typology building as analytical tools.

Mapping music education in Australia

Music education research in Australia has grown almost exponentially over the past 25 years. Particularly in the area of doctoral research studies, there has been a substantial increase in the number of theses completed from two in 1977 to 72 in 2002. In addition, there have been increases in professional research undertaken by university academics, in the number of nationally competitive research grants being awarded by the Australian Research Council and other research funding agencies, and in commissioned research studies. This article reviews the various types of music education research being undertaken in Australia and also discusses the dissemination of the findings of research through articles in national and international scholarly journals and papers presented at local and international conferences. One of the conclusions drawn is that Australian music education has ‘come of age’ in terms of both the quantity and the quality of its national research profile.

Multi-temporal land use mapping using remotely sensed techniques and the integration of a pollutant load model in a GIS

Estimation of nutrient load production based on multi-temporal remotely sensed land-use data for the Glenelg-Hopkins region in southwest Victoria, Australia, is discussed. Changes in land use were mapped using archived Landsat data and computerized classification techniques. Land-use
change is unparalleled in recent history, with 13% of the region transformed in the last decade. Total nitrogen and phosphorus loading were estimated using an export coefficient model. The analysis demonstrated a disturbing increase in nitrogen and phosphorus loadings from 1995 to 2002. Whilst such increases were suspected from past anecdotal and ad-hoc evidence, our modelling quantitatively estimated such increases and thus demonstrated the enormous potential of using remote sensing and GIS for monitoring land-use change and hence improve land-use management.

Hydrology or floristics? Mapping and classification of wetlands in Victoria, Australia, and implications for conservation planning

A national approach to the conservation of biodiversity in Australia’s freshwater ecosystems is a high priority. This requires a consistent and comprehensive system for the classification, inventory, and assessment of wetland ecosystems. This paper, using the State of Victoria as a case study, compares two classification systems that are commonly utilized to delineate and map wetlands—one based on hydrology (Victorian Wetland Database [VWD]) and one based on indigenous vegetation types and other natural features (Ecological Vegetation Classes [EVC]). We evaluated the extent of EVC mapping of wetlands relative to the VWD classification system using a number of datasets within a geographical information system. There were significant differences in the coverage of extant EVCs across bioregions, different-sized wetlands, and VWD wetland types. Resultant depletion levels were markedly different when examined using the two systems, with depletion levels, and therefore perceived conservation status, of EVCs being significantly higher. Although there is little doubt that many wetland ecosystems in Victoria are in fact threatened, the extent of this threat cannot accurately be determined by relying on the EVC mapping as it currently stands. The study highlighted the significant impact wetland classification methods have in determining the conservation status of freshwater ecosystems.

Mapping the hot deformation microstructure of Ni-30Fe alloy

The evolution of structure during the hot working of an austenitic Ni-30%Fe alloy is studied using EBSD analysis of samples tested in torsion. A microstructural map in temperature-strain space that plots grain size, cell size, fracture and dynamic recrystallization is presented.

Experimental study of ostensibly shamanic journeying imagery in naďve participants II: phenomenological mapping and modified affect bridge

This study develops the methodological framework advanced in Rock, Baynes, and Casey's (2005) experimental study of ostensibly shamanic journeying imagery in naïve participants. Specifically, the present study experimentally investigates the impact of the word landscape, featured in Harner's (1990) shamanic journeying to the Lower World instructions, on the number of landscape-related images reported; examines the origins of ostensibly shamanic journeying images; and maps the phenomenological state effects of shamanic journeying to the Lower World. Sixtyeight naïve participants were randomly assigned to one of three conditions: either the original or a revised version of Harner's (1990) instructions coupled with monotonous percussion drumming at 8 beats-per-second for 15 minutes, or sitting quietly with eyes open for 15 minutes. Each participant's subjective experience was retrospectively assessed using the Phenomenology of Consciousness Inventory (PCI) (Pekala 1991) and a mental imagery checklist. Subsequently, participants were administered the Modified Affect Bridge for the purpose of exploring the origins of mental imagery experienced during the experimental conditions. The results indicated that there was a statistically significant difference between conditions with regard to the number of ostensibly shamanic journeying images reported, but not between treatment conditions with regard to the number of landscaperelated images reported. There were no significant relationships between condition and mental imagery derived from autobiographical memories. There were statistically significant differences between conditions with regard to the PCI dimensions of fear, altered state of awareness, and arousal.

Mapping pedagogy to technology - a simple model

As academics we are often encouraged to “go online” by our institution, by either moving or supplementing our teaching in an online environment. We have several options. We could simply attempt to replicate our face-to-face teaching, in effect changing nothing; we can enhance our face-to-face teaching with the available technology; or we can transform our face-to-face teaching by the available technology. The approach we choose will be determined by several factors, one of which will be our existing knowledge of the technological environment we are using. In this paper I propose a simple framework which provides novice eTeachers in particular with a simple mapping from classroom activity to technological functionality, reducing the need to have extensive technological literacy of the learning environment when designing online activities initially.

Optimization of MLP parameters on mineral potential mapping tasks

Mineral potential mapping is the process of combining a set of input maps, each representing a distinct geo-scientific variable, to produce a single map which ranks areas according to their potential to host deposits of a particular type. The maps are combined using a mapping function which must be either provided by an expert (knowledge-driven approach), or induced from sample data (data-driven approach). Current data-driven approaches using multilayer perceptrons (MLPs) to represent the mapping function have several inherent problems: they rely heavily on subjective judgment in selecting training data and are highly sensitive to this selection; they do not utilize the contextual information provided by unlabeled data; and, there is no objective interpretation of the values output by the MLP. This paper presents a novel approach which overcomes these three problems.

Comparison of MLP and Bayesian approaches on mineral prospectivity mapping tasks

Mineral Prospectivity Mapping is the process of combining maps containing different geoscientific data sets to produce a single map depicting areas ranked according to their potential to host mineral deposits of a particular type. This paper outlines two approaches for deriving a function which can be used to assign to each cell in the study area a value representing the posterior probability that the cell contains a deposit of the sought-after mineral. One approach is based on estimating probability density functions (pdfs); the second uses multilayer perceptrons (MLPs). Results are provided from applying these approaches to geoscientific datasets covering a region in North Western Victoria, Australia. The results demonstrate that while both the Bayesian approach and the MLP approach yield similar results when the number of input dimensions is small, the Bayesian approach rapidly becomes unstable as the number of input dimensions increases, with the resulting maps displaying high sensitivity to the number of mixtures used to model the distributions. However, despite the fact that Bayesian assigned values cannot be interpreted as posterior probabilities in high dimensional input spaces, the pixel favorability rankings produced by the two methods is similar.