Spatial and temporal variation in distribution of mangroves in Moreton Bay, subtropical Australia: a comparison of pattern metrics and change detection analyses based on aerial photographs

An assessment of the changes in the distribution and extent of mangroves within Moreton Bay, southeast Queensland, Australia, was carried out. Two assessment methods were evaluated: spatial and temporal pattern metrics analysis, and change detection analysis. Currently, about 15,000 ha of mangroves are present in Moreton Bay. These mangroves are important ecosystems, but are subject to disturbance from a number of sources. Over the past 25 years, there has been a loss of more than 3800 ha, as a result of natural losses and mangrove clearing (e.g. for urban and industrial development, agriculture and aquaculture). However, areas of new mangroves have become established over the same time period, offsetting these losses to create a net loss of about 200 ha. These new mangroves have mainly appeared in the southern bay region and the bay islands, particularly on the landward edge of existing mangroves. In addition, spatial patterns and species composition of mangrove patches have changed. The pattern metrics analysis provided an overview of mangrove distribution and change in the form of single metric values, while the change detection analysis gave a more detailed and spatially explicit description of change. An analysis of the effects of spatial scales on the pattern metrics indicated that they were relatively insensitive to scale at spatial resolutions less than 50 m, but that most metrics became sensitive at coarser resolutions, a finding which has implications for mapping of mangroves based on remotely sensed data. (C) 2003 Elsevier Science B.V. All rights reserved.

Analysis of soil wetting and solute transport in subsurface trickle irrigation

The increased use of trickle or drip irrigation is seen as one way of helping to improve the sustainability of irrigation systems around the world. However, soil water and solute transport properties and soil profile characteristics are often not adequately incorporated in the design and management of trickle systems. In this paper, we describe results of a simulation study designed to highlight the impacts of soil properties on water and solute transport from buried trickle emitters. The analysis addresses the influence of soil hydraulic properties, soil layering, trickle discharge rate, irrigation frequency, and timing of nutrient application on wetting patterns and solute distribution. We show that (1) trickle irrigation can improve plant water availability in medium and low permeability fine-textured soils, providing that design and management are adapted to account for their soil hydraulic properties, (2) in highly permeable coarse-textured soils, water and nutrients move quickly downwards from the emitter, making it difficult to wet the near surface zone if emitters are buried too deep, and (3) changing the fertigation strategy for highly permeable coarse-textured soils to apply nutrients at the beginning of an irrigation cycle can maintain larger amounts of nutrient near to and above the emitter, thereby making them less susceptible to leaching losses. The results demonstrate the need to account for differences in soil hydraulic properties and solute transport when designing irrigation and fertigation management strategies. Failure to do this will result in inefficient systems and lost opportunities for reducing the negative environmental impacts of irrigation.

Cost effectiveness of adding magnetic resonance imaging to the usual management of suspected scaphoid fractures

Objective: To determine the cost effectiveness of a magnetic resonance imaging scan (MRI) within 5 days of injury compared with the usual management of occult scaphoid fracture. Methods: All patients with suspected scaphoid fractures in five hospitals were invited to participate in a randomised controlled trial of usual treatment with or without an MRI scan. Healthcare costs were compared, and a cost effectiveness analysis of the use of MRI in this scenario was performed. Results: Twenty eight of the 37 patients identified were randomised: 17 in the control group, 11 in the MRI group. The groups were similar at baseline and follow up in terms of number of scaphoid fractures, other injuries, pain, and function. Of the patients without fracture, the MRI group had significantly fewer days immobilised: a median of 3.0 (interquartile range 3.0-3.0) v 10.0 (7-12) in the control group (p = 0.006). The MRI group used fewer healthcare units (median 3.0, interquartile range 2.0-4.25) than the control group (5.0, 3.0-6.5) (p = 0.03 for the difference). However, the median cost of health care in the MRI group ($594.35 AUD, $551.35-667.23) was slightly higher than in the control group ($428.15, $124.40-702.65) (p = 0.19 for the difference). The mean incremental cost effectiveness ratio derived from this simulation was that MRI costs $44.37 per day saved from unnecessary immobilisation (95% confidence interval $4.29 to $101.02). An illustrative willingness to pay was calculated using a combination of the trials measure of the subjects' individual productivity losses and the average daily earnings. Conclusions: Use of MRI in the management of occult scaphoid fracture reduces the number of days of unnecessary immobilisation and use of healthcare units. Healthcare costs increased non-significantly in relation to the use of MRI in this setting. However, when productivity losses are considered, MRI may be considered cost effective, depending on the individual case.

Review of genetic and epigenetic alterations in hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is associated with multiple risk factors and is believed to arise from pre-neoplastic lesions, usually in the background of cirrhosis. However, the genetic and epigenetic events of hepatocarcinogenesis are relatively poorly understood. HCC display gross genomic alterations, including chromosomal instability (CIN), CpG island methylation, DNA rearrangements associated with hepatitis B virus (HBV) DNA integration, DNA hypomethylation and, to a lesser degree, microsatellite instability. Various studies have reported CIN at chromosomal regions, 1p, 4q, 5q, 6q, 8p, 10q, 11p, 16p, 16q, 17p and 22q. Frequent promoter hypermethylation and subsequent loss of protein expression has also been demonstrated in HCC at tumor suppressor gene (TSG), p16, p14, p15, SOCS1, RIZ1, E-cadherin and 14-3-3 sigma. An interesting observation emerging from these studies is the presence of a methylator phenotype in hepatocarcinogenesis, although it does not seem advantageous to have high levels of microsatellite instability. Methylation also appears to be an early event, suggesting that this may precede cirrhosis. However, these genes have been studied in isolation and global studies of methylator phenotype are required to assess the significance of epigenetic silencing in hepatocarcinogenesis. Based on previous data there are obvious fundamental differences in the mechanisms of hepatic carcinogenesis, with at least two distinct mechanisms of malignant transformation in the liver, related to CIN and CpG island methylation. The reason for these differences and the relative importance of these mechanisms are not clear but likely relate to the etiopathogenesis of HCC. Defining these broad mechanisms is a necessary prelude to determine the timing of events in malignant transformation of the liver and to investigate the role of known risk factors for HCC.

The effects of moderate and low levels of acoustic overstimulation on stereocilia and their tip links in the guinea pig

Guinea pigs were exposed to pure tones of 10 kHz at intensities between 98 and 115 dB SPL for 5-30 min, to produce varying degrees of acoustic trauma. Changes in auditory thresholds were measured electrophysiologically, and the animals were immediately fixed for scanning electron microscopy. Correlation between morphological changes to the hair bundle and losses in threshold, showed that with the smallest degrees of trauma (98 dB SPL for 15 min, mean maximum threshold loss of 22 dB), damage was confined to a small stretch of inner hair cells (IHC), with only subtle changes to the stereocilia of the outer hair cells (OHC). At exposure intensities greater than 102 dB SPL (duration: 15 min) the IHC stereocilia in the centre of the lesion were always substantially disarrayed. Substantial damage to the OHC bundles was seen only with exposures above 110 dB SPL(duration: greater than or equal to 5 min), producing threshold losses of 50 dB or more. Tip links were lost only where the stereocilia were disarrayed. It is concluded that the tip links are not the most vulnerable components of the cochlear hair cell, but that relatively low levels of acoustic stimulation can cause significant damage to the stereociliary bundle of the IHCs.

A compact shock-assisted free-piston driver for impulse facilities

A free-piston driver that employs entropy-raising shock processes with diaphragm rupture has been constructed, which promises significant theoretical advantages over isentropic compression. Results from a range of conditions with helium and argon driver gases are reported. Significant performance gains were achieved in some test cases. Heat losses are shown to have a strong effect on driver processes. Measurements compare well with predictions from a quasi-one-dimensional numerical code.

Measuring macromolecular diffusion using heteronuclear multiple-quantum pulsed-field-gradient NMR

We have previously shown that H-1 pulsed-field-gradient (PFG) NMR spectroscopy provides a facile method for monitoring protein self-association and can be used, albeit with some caveats, to measure the apparent molecular mass of the diffusant [Dingley et al. (1995) J. Biomol. NMR, 6, 321-328]. In this paper we show that, for N-15-labelled proteins, selection of H-1-N-15 multiple-quantum (MQ) coherences in PFG diffusion experiments provides several advantages over monitoring H-1 single-quantum (SQ) magnetization. First, the use of a gradient-selected MQ filter provides a convenient means of suppressing resonances from both the solvent and unlabelled solutes. Second, H-1-N-15 zero-quantum coherence dephases more rapidly than H-1 SQ coherence under the influence of a PFG. This allows the diffusion coefficients of larger proteins to be measured more readily. Alternatively, the gradient length and/or the diffusion delay may be decreased, thereby reducing signal losses from relaxation. In order to extend the size of macromolecules to which these experiments can be applied, we have developed a new MQ PFG diffusion experiment in which the magnetization is stored as longitudinal two-spin order for most of the diffusion period, thus minimizing sensitivity losses due to transverse relaxation and J-coupling evolution.

Fluid shifts resulting from exercise in rats as detected by bioelectrical impedance

Purpose: This study was designed to investigate the immediate effect of exercise intensity and duration on body fluid volumes in rats throughout a 3-wk exercise program. Methods: Changes in the extracellular water (ECW) and total body water (TBW) volumes of rats were measured preexercise and postexercise using multiple frequency bioelectrical impedance analysis. Groups of rats were exercised at two intensities (6 m.min(-1) and 12 m.min(-1)) for two exercise times (60 min and 90 min) 5 d.wk(-1) during a 3-wk period. Changes in plasma electrolytes, glucose, and lactate resulting from the exercise were also measured on 3 d of each week. Results: Each group of animals showed significant losses in ECW and TBW as a direct result of daily exercise. The magnitude of fluid loss was directly related to the intensity of the exercise, bur not to exercise duration; although the magnitude of daily fluid loss at the higher intensity exercise (12 m.min(-1)) decreased as the study progressed, possibly indicating a training effect. Conclusion: At low-intensity exercise, there is a small bur significant loss in both TBW and ECW fluids, and the magnitude of these losses does not change throughout a 3-wk exercise program. At moderate levels of exercise intensity, there is a greater loss of both TBW and ECW fluids. However, the magnitudes of these losses decrease significantly during the 3-wk exercise program, thus demonstrating a training effect.

Temperature variation within and between nests of the green sea turtle, Chelonia mydas (Chelonia : Cheloniidae) on Heron Island, Great Barrier Reef

Four temperature data-loggers were placed in each of five green sea turtle nests on Heron Island in the 1998-99 nesting season. Temperatures in all nests increased as incubation progressed due to general sand heating and increased metabolic heat production of the developing embryos. Even at the top of nests no daily diurnal fluctuation in temperature was evident. The temperature of eggs in the middle of the nest increased above those in the nest periphery during the last third of incubation. However, this metabolic nest heating would have little effect on hatchling sex ratio because it occurred after the sex-determining period. Small differences in temperature between regions of a nest persisted throughout incubation and may be important in ensuring the production of at least some individuals of the opposite sex in nests that have temperatures close to either the all-male or all-female determining temperatures. Location and degree of shading of nests had little effect on mean nest temperature, but deeper nests were generally cooler and therefore were predicted to produce a higher proportion of males than were shallower nests. Nest temperature profile data indicated that the 1998-99 nesting season on Heron Island would have produced a strongly female-biased sex ratio amongst hatchlings.

Solution structures by H-1 NMR of the novel cyclic trypsin inhibitor SFTI-1 from sunflower seeds and an acyclic permutant

SFTI-1 is a recently discovered cyclic peptide trypsin inhibitor from sunflower seeds comprising 14 amino acid residues. It is the most potent known Bowman-Birk inhibitor and the only naturally occurring cyclic one. The solution structure of SFTI-1 has been determined by H-1-NMR spectroscopy and compared with a synthetic acyclic permutant. The solution structures of both are remarkably similar. The lowest energy structures from each family of 20 structures of cyclic and acyclic SFTI-1 have an rmsd over the backbone and heavy atoms of 0.29 Angstrom and 0.66 Angstrom, respectively. The structures consist of two short antiparallel beta -strands joined by an extended loop containing the active site at one end. Cyclic SFTI-1 also has a hairpin turn completing the cycle. Both molecules contain particularly stable arrangements of cross-linking hydrogen bonds between the beta -strands and a single disulfide bridge, making them rigid and well defined in solution. These stable arrangements allow both the cyclic and acyclic variants of SFTI-1 to inhibit trypsin with very high potencies (0.5 nM and 12.1 nM, respectively). The cyclic nature of SFTI-1 appears to have evolved to provide higher trypsin inhibition as well as higher stability. The solution structures are similar to the crystal structure of the cyclic inhibitor in complex with trypsin. The lack of a major conformational change upon binding suggests that the structure of SFTI-1 is rigid and already pre-organized for maximal binding due to minimization of entropic losses compared to a more flexible ligand. These properties make SFTI-1 an ideal platform for the design of small peptidic pharmaceuticals or pesticides. (C) 2001 Academic Press.

Denitrification, leaching and immobilisation of N-15-labelled nitrate in winter under windrowed harvesting residues in hoop pine plantations of 1-3 years old in subtropical Australia

A field study was carried out to investigate the impacts of windrowed harvesting residues on denitrification, immobilisation and leaching of N-15-labelled nitrate applied at 20 kg N ha(-1) to microplots in second-rotation hoop pine (Araucaria cunninghamii) plantations of 1-3 years old in southeast Queensland, Australia. The PVC microplots were 235 mm in diameter and 150 mm. long, and driven into the 100 mm soil. There were three replications of such microplots for each of the six treatments which were areas just under and between 1-, 2- and 3-year-old windrows of harvesting residues. Based on gaseous N losses estimated by the difference between the recoveries of bromide (Br) applied at 100 kg Br ha(-1) and N-15-labelled nitrate, denitrification was highest (23% based on N-15 loss) in the areas just under the 1-year-old windrows 25 days after a simulated 75 mm rainfall and following several natural rainfall events. There was no significant difference in N-15 losses (14-17%) among the other treatments. The N-15 immobilisation rate was highest for microplots in the areas between the 1-year-old windrows and generally higher for microplots in the areas just under the windrows (30-39%) than that (26-30%) between the windrows. Direct measurement of N-15 gas emissions (N-15(2) + (N2O)-N-15) confirmed that the highest denitrification rate occurred in the microplots under the 1-year-old windrows although the gaseous N-15 loss calculated by gas emission was only about one-quarter that estimated by the N-15 mass balance method. A significant, positive linear relationship (P < 0.05) existed between the gaseous N-15 losses measured by the two methods used. The research indicates that considerable mineral N could be lost via denitrification during the critical inter-rotation period and early phase of the second rotation. However, the impacts of windrowed harvesting residues on N losses via denitrification might only last for a period of about 2 years. Published by Elsevier Science B.V.

Fate of urea nitrogen applied to a banana crop in the wet tropics of Queensland

This paper reports a study in the wet tropics of Queensland on the fate of urea applied to a dry or wet soil surface under banana plants. The transformations of urea were followed in cylindrical microplots (10.3 cm diameter x 23 cm long), a nitrogen (N) balance was conducted in macroplots (3.85 m x 2.0 m) with N-15 labelled urea, and ammonia volatilization was determined with a mass balance micrometeorological method. Most of the urea was hydrolysed within 4 days irrespective of whether the urea was applied onto dry or wet soil. The nitrification rate was slow at the beginning when the soil was dry, but increased greatly after small amounts of rain; in the 9 days after rain 20% of the N applied was converted to nitrate. In the 40 days between urea application and harvesting, the macroplots the banana plants absorbed only 15% of the applied N; at harvest the largest amounts were found in the leaves (3.4%), pseudostem (3.3%) and fruit (2.8%). Only 1% of the applied N was present in the roots. Sixty percent of the applied N was recovered in the soil and 25% was lost from the plant-soil system by either ammonia volatilization, leaching or denitrification. Direct measurements of ammonia volatilization showed that when urea was applied to dry soil, and only small amounts of rain were received, little ammonia was lost (3.2% of applied N). In contrast, when urea was applied onto wet soil, urea hydrolysis occurred immediately, ammonia was volatilized on day zero, and 17.2% of the applied N was lost by the ninth day after that application. In the latter study, although rain fell every day, the extensive canopy of banana plants reduced the rainfall reaching the fertilized area under the bananas to less than half. Thus even though 90 mm of rain fell during the volatilization study, the fertilized area did not receive sufficient water to wash the urea into the soil and prevent ammonia loss. Losses by leaching and denitrification combined amounted to 5% of the applied N.

Significance of gaseous nitrogen loss from a tropical dairy pasture fertilised with urea

This paper reports a study in the wet tropics of Queensland on the fate of urea applied to a dairy pasture in the absence of grazing animals. A nitrogen balance was conducted in cylindrical plots with N-15-labelled urea, and ammonia volatilisation was determined using a mass balance micrometeorological method. The pasture plants took up 42% of the applied nitrogen in the 98 days between fertiliser application and harvest. At harvest 18% of the applied nitrogen was found in the soil, and 40% was lost from the plant-soil system. The micrometeorological study showed that 20% of the unrecovered nitrogen was lost by ammonia volatilisation. As there was no evidence for leaching or runoff losses it was concluded that the remaining 20% of the applied nitrogen was lost by denitrification. It is evident from these results that fertiliser nitrogen is not being used efficiently on dairy pastures, and that practices need to be changed to conserve fertiliser nitrogen and reduce contamination of the environment.

Loss as a universal concept: Review of the literature to identify common aspects of loss in diverse situations

It has long been recognized that loss and its associated grief are important elements of many adverse life events that affect the entire global population: death, disability, traumatic events, abuse., terminal and chronic illness, aging, addiction, unemployment, relationship breakdown, war, migration, and educational failure. While there is significant empirical evidence of the potential deleterious effects of specific situations of loss across the global community, systematic discussion concerning the common elements of loss that are associated with adverse life situations in general has been limited. This review of the theoretical and empirical literature concerning various losses and the recommendations for care of those affected by such losses identifies common aspects of situations of loss and common recommendations in the care of those confronted by such losses. These common themes of loss are described by simple summary statements that can be communicated to a broad audience, hence enhancing community education and, potentially, community-wide mental health promotion.

The filter system for tertiary treatment of sewage effluent by land application - its performance in a subtropical environment

FILTER is an innovative, CSIRO developed system for treating effluent using high rate land application and subsequent effluent recapture via a closely spaced, subsurface drainage network. We report on the summer performance of a FILTER system established in a subtropical environment on a relatively impermeable swelling clay soil underlain by a deep regional water table. Using secondary treated sewage effluent, the FILTER system produced effluent of tertiary nutrient standards (less than or equal to5 mg/L TN; less than or equal to1 mg/L TP), with salinity levels suitable for subsequent irrigation reuse (EC less than or equal to2.5 dS/m). Removal of faecal coliforms was considerably less effective. The hydraulic loading rate achieved was about two and a half times larger than conventional irrigation demand, but this was associated with high deep percolation losses (e 3 mm/day). Comparisons are made with the original FILTER system developed and tested by Jayawardane et al. in temperate Australia. Suggestions are made for modifications to, and further testing of FILTER in a subtropical environment.