A fast semi-implicit difference method for a nonlinear two-sided space-fractional diffusion equation with variable diffusivity coefficients

In this paper, we derive a new nonlinear two-sided space-fractional diffusion equation with variable coefficients from the fractional Fick’s law. A semi-implicit difference method (SIDM) for this equation is proposed. The stability and convergence of the SIDM are discussed. For the implementation, we develop a fast accurate iterative method for the SIDM by decomposing the dense coefficient matrix into a combination of Toeplitz-like matrices. This fast iterative method significantly reduces the storage requirement of O(n2)O(n2) and computational cost of O(n3)O(n3) down to n and O(nlogn)O(nlogn), where n is the number of grid points. The method retains the same accuracy as the underlying SIDM solved with Gaussian elimination. Finally, some numerical results are shown to verify the accuracy and efficiency of the new method.

The synthesis, characterization, X-ray structure and magnetism of dinuclear-based bis[μ-(1,1,3,3-tetracyano-2-ethoxypropenido-κ2N,N′) (1,1,3,3-tetracyano-2-ethoxypropenido-κN)(2,2′-bipyridine)copper(II)] organized in alternating chains via semi-coordinating Cu–N distances

The monoanionic ligand 1,1,3,3 tetracyano-2 ethoxypropenide (tcnoet) is reported with its Cu(II)–bpy complex of formula [Cu2(µ-tcnoet)2(tcnoet)2(bpy)2]. The structure has been determined using X-ray diffraction and features an alternating chain with bridging tcnoet ligands. One ligand acts as a bidentate, dinucleating ligand with one short Cu–N and one medium Cu–N bond, whereas the other tcnoet is largely monodentate, albeit with a very weak interdimer Cu–N bond. Despite the arrangement in dinuclear units, further arranged into linear chains through the non-bridging tcnoet ligand, the compound shows no significant magnetic exchange, as deduced from magnetic susceptibility down to 4 K. Ligand-field, IR and EPR spectra in the solid state and in frozen solution are reported and are consistent with the overall structure.

Semi-automated annotation of environmental acoustic recordings

Environmental sensors collect massive amounts of audio data. This thesis investigates computational methods to support human analysts in identifying faunal vocalisations from that audio. A series of experiments was conducted to trial the effectiveness of novel user interfaces. This research examines the rapid scanning of spectrograms, decision support tools for users, and cleaning methods for folksonomies. Together, these investigations demonstrate that providing computational support to human analysts increases their efficiency and accuracy; this allows bioacoustics projects to efficiently utilise their valuable human analysts.

Identifying vertebral end plate lesions (schmorl's nodes) using a semi-automatic method

INTRODUCTION There is a large range in the reported prevalence of end plate lesions (EPLs), sometimes referred to as Schmorl's nodes in the general population (3.8-76%). One possible reason for this large range is the differences in definitions used by authors. Previous research has suggested that EPLs may potentially be a primary disturbance of growth plates that leads to the onset of scoliosis. The aim of this study was to develop a technique to measure the size, prevalence and location of EPLs on Computed Tomography (CT) images of scoliosis patients in a consistent manner. METHODS A detection algorithm was developed and applied to measure EPLs for five adolescent females with idiopathic scoliosis (average age 15.1 years, average major Cobb 60°). In this algorithm, the EPL definition was based on the lesion depth, the distance from the edge of the vertebral body and the gradient of the lesion edge. Existing low-dose, CT scans of the patients' spines were segmented semi-automatically to extract 3D vertebral endplate morphology. Manual sectioning of any attachments between posterior elements of adjacent vertebrae and, if necessary, endplates was carried out before the automatic algorithm was used to determine the presence and position of EPLs. RESULTS EPLs were identified in 15 of the 170 (8.8%) endplates analysed with an average depth of 3.1mm. 73% of the EPLs were seen in the lumbar spines (11/15). A sensitivity study demonstrated that the algorithm was most sensitive to changes in the minimum gradient required at the lesion edge. CONCLUSION An imaging analysis technique for consistent measurement of the prevalence, location and size of EPLs on CT images has been developed. Although the technique was tested on scoliosis patients, it can be used to analyse other populations without observer errors in EPL definitions.

Profiles of illicit drug use during annual key holiday and control periods in Australia: Wastewater analysis in an urban, a semi-rural and a vacation area

AIMS: To examine changes in illicit drug consumption between peak holiday season (23 December-3 January) in Australia and a control period two months later in a coastal urban area, an inland semi-rural area and an island populated predominantly by vacationers during holidays. DESIGN: Analysis of representative daily composite wastewater samples collected from the inlet of the major wastewater treatment plant in each area. SETTING: Three wastewater treatment plants. PARTICIPANTS: Wastewater treatment plants serviced approximately 350, 000 persons in the urban area, 120,000 in the semi-rural area and 1100-2400 on the island. MEASUREMENTS: Drug residues were analysed using liquid chromatography coupled to a tandem mass spectrometer. Per capita drug consumption was estimated. Changes in drug use were quantified using Hedges' g. FINDINGS: During the holidays, cannabis consumption in the semi-rural area declined (g = -2.8) as did methamphetamine (-0.8), whereas cocaine (+1.5) and ecstasy (+1.6) use increased. In the urban area, consumption of all drugs increased during holidays (cannabis +1.6, cocaine +1.2, ecstasy +0.8 and methamphetamine +0.3). In the vacation area, methamphetamine (+0.7), ecstasy (+0.7) and cocaine (+1.1) use increased, but cannabis (-0.5) use decreased during holiday periods. CONCLUSIONS: While the peak holiday season in Australia is perceived as a period of increased drug use, this is not uniform across all drugs and areas. Substantial declines in drug use in the semi-rural area contrasted with substantial increases in urban and vacation areas. Per capita drug consumption in the vacation area was equivalent to that in the urban area, implying that these locations merit particular attention for drug use monitoring and harm minimisation measures.

Illicit drug use between an annual key holiday and a control period: Wastewater analysis in a semi-rural, an urban and a vacation area

Introduction and Aims: Holiday periods are potentially a time for increased substance use as social events and private parties are more common. Data on community illicit drug consumption during holiday periods are limited. Besides existing methods for determining drug use, such as population surveys, one emerging method is to measure illicit drugs and/or their metabolites in wastewater samples. This study examined the change in consumption of cannabis, methamphetamine, cocaine and 3,4- methylenedioxymethamphetamine in three different types of areas (an inland semi-rural area, a coastal urban area and a vacation island) with respect to holiday times. Design and Methods: Samples were collected at the inlet of the major wastewater treatment plant in each area during a key annual holiday (i.e. the summer holiday including Christmas and New Year) and control period. Illicit drug residues in the daily composited samples were measured by liquid chromatography coupled with tandem mass spectrometry. Results: Drug use varied substantially among the three areas within each monitoring period as well as between the holiday and control period within each area. Use consistently increased and peaked over New Year particularly for cocaine and 3,4-methylenedioxymethamphetamine whereas cannabis and methamphetamine were relatively less subjected to holiday times in all the areas. Discussion and Conclusions: Wastewater sampling and analysis provides higher spatio-temporal resolution than national surveys and supplements drug epidemiology studies originating primary in metropolitan locations. Such data is essential for policy makers to plan potential intervention strategies associated with these illicit substances in regional areas and other settings besides urban areas in the future.

Semi-supervised document clustering via loci

Document clustering is one of the prominent methods for mining important information from the vast amount of data available on the web. However, document clustering generally suffers from the curse of dimensionality. Providentially in high dimensional space, data points tend to be more concentrated in some areas of clusters. We take advantage of this phenomenon by introducing a novel concept of dynamic cluster representation named as loci. Clusters’ loci are efficiently calculated using documents’ ranking scores generated from a search engine. We propose a fast loci-based semi-supervised document clustering algorithm that uses clusters’ loci instead of conventional centroids for assigning documents to clusters. Empirical analysis on real-world datasets shows that the proposed method produces cluster solutions with promising quality and is substantially faster than several benchmarked centroid-based semi-supervised document clustering methods.

Assessment of an environmentally friendly, semi-pelagic fish trawl

Minimising catches of non-target animals in a trawl fishery reduces the impact on a marine community and may help to sustain the fishery resource in the long term. Hence the desirability for trawls that minimise impacts on non-target species while maintaining catches of target species. This study resulted from a need to further develop easily handled, semi-pelagic style trawls for Australia's Northern Fish Trawl Fishery. In November 1993 we compared catches from three differently rigged versions of a demersal wing trawl: one fished in a standard demersal configuration with its footrope on the sea bed, and two fished semi-pelagically, with their footropes raised to either 0.4-0.5 or 0.8-0.9 m above the sea bed. At two sites in the northeast Gulf of Carpentaria, each trawl type was used on the same combination of sites, grids within sites and times of day. Catches of the main target species (Lutjanus malabaricus and Lutjanus erythropterus) by the three trawl types were not significantly different. However, the mean catches of both these species and of other commercially important snappers, were highest in the semi-pelagic trawl raised 0.4-0.5 m above the sea bed. This increase could be due to a larger trawl spread or to the whole rig fishing higher in the water column. Of the 107 species of fishes analysed, 61 were caught in greater abundance in the demersal trawl. Seven species were caught more effectively in the semi-pelagic trawl with the footrope 0.4-0.5 m above the substrate; none was caught most effectively with the footrope set at 0.8-0.9 m. Epibenthic byproduct species (squid and Thenus orientalis), fish bycatch, sponges and other epibenthic invertebrates were also caught in lower numbers in the semi-pelagic trawls. The semi-pelagic trawls convincingly caught less (in both numbers and biomass) of the unwanted species which are normally discarded. Semi-pelagic fish trawls of the types tested would be suitable for Australia's Northern Fish Trawl Fishery and probably other demersal trawl fisheries that would benefit from the conservation of non-target epibenthic communities.

Muscle morphometry of the individual hamstring muscles in semi-elite AFL Players: Preliminary findings from a longitudinal study

Hamstring strains in the Australian Football League (AFL) have a high incidence (15%) and recurrence rate (34%) with lateral hamstring injuries most common (83%). Retrospective studies have found significant muscle volume asymmetries ≤23 months post hamstring injury; however examination of the association between hamstring strains and muscle asymmetry has not been investigated prospectively. This study presents baseline data from a longitudinal study focusing on individual hamstring morphometry in uninjured and injured semi-elite AFL players.

The Context-integrity of the global carbon regime: The relevance and impact of the World Trade Organization

In the study of the integrity of the global carbon regime there are a number of institutions that must be considered for their impacts on this system. In particular, the subject matter of this chapter is concerned with the main international institution for trade, the World Trade Organization (the WTO). Otherwise stated, this chapter is concerned with how the institutional integrity of the global carbon regime aligns with the values and policy objectives of the WTO. This is done with a view to consider whether the global carbon regime aligns with these values and objectives in a way demonstrative of context-integrity. This alignment is not a single-sided undertaking and, therefore, it is essential that the underlying values of the WTO themselves align with the global carbon regime. I suggest this is particularly crucial given the importance of the objectives of the climate change regime, and the scientific predictions of the current climate projections.

A computer code for enclosed natural convection in the boundary layer regime

A computer code is developed for the numerical prediction of natural convection in rectangular two-dimensional cavities at high Rayleigh numbers. The governing equations are retained in the primitive variable form. The numerical method is based on finite differences and an ADI scheme. Convective terms may be approximated with either central or hybrid differencing for greater stability. A non-uniform grid distribution is possible for greater efficiency. The pressure is dealt with via a SIMPLE type algorithm and the use of a fast elliptic solver for the solenoidal velocity correction field significantly reduces computing times. Preliminary results indicate that the code is reasonably accurate, robust and fast compared with existing benchmarks and finite difference based codes, particularly at high Rayleigh numbers. Extension to three-dimensional problems and turbulence studies in similar geometries is readily possible and indicated.

The laminar boundary layer regime for natural convection of air in a square cavity

Numerical predictions are obtained for laminar natural convection of air in a square two dimensional cavity at high Rayleigh numbers. Proper resolution of the core reveals weak multi-cellular structure which varies in a complex manner as the effects of convection are increased. The end of the steady laminar regime is numerically estimated to occur at Ra=2.2x10^8.

Use of semi-active dampers in seismic mitigation of building structures

This research provides information for providing the required seismic mitigation in building structures through the use of semi active and passive dampers. The Magneto-Rheological (MR) semi-active damper model was developed using control algorithms and integrated into seismically excited structures as a time domain function. Linear and nonlinear structure models are evaluated in real time scenarios. Research information can be used for the design and construction of earthquake safe buildings with optimally employed MR dampers and MR-passive damper combinations.

Ethical Values and the Integrity of the Climate Change Regime

This book investigates the ethical values that inform the global carbon integrity system, and reflects on alternative norms that could or should do so. The global carbon integrity system comprises the emerging international architecture being built to respond to the climate change. This architecture can be understood as an 'integrity system'- an inter-related set of institutions, governance arrangements, regulations and practices that work to ensure the system performs its role faithfully and effectively. This volume investigates the ways ethical values impact on where and how the integrity system works, where it fails, and how it can be improved. With a wide array of perspectives across many disciplines, including ethicists, philosophers, lawyers, governance experts and political theorists, the chapters seek to explore the positive values driving the global climate change processes, to offer an understanding of the motivations justifying the creation of the regime and the way that social norms impact upon the operation of the integrity system. The collection focuses on the nexus between ideal ethics and real-world implementation through institutions and laws. The book will be of interest to policy makers, climate change experts, carbon taxation regulators, academics, legal practitioners and researchers.