Effect of sampling density on the measurement of stream condition indicators in two lowland Australian streams

There is widespread application of indicators to the assessment of environmental condition of streams. These indicators are intended for use by managers in making various comparative and absolute assessments and often have a role in resource allocation and performance assessment. Therefore, the problem of formally defining confidence in the results is important but difficult because the sampling strategies used are commonly based on a compromise between the requirements of statistical rigour and the pragmatic issues of access and resources. It is rare to see this compromise explicitly considered and consequently there is seldom quantification of the uncertainty that could affect the confidence a manager has in an indicator. In this paper, we present a method for quantitatively assessing the tradeoffs between sampling density and uncertainty in meeting various monitoring objectives. Assessments using judgement‐based representative reaches are shown to be unreliable; instead a sampling approach is recommended based on the random selection of measuring sites. A detailed dataset was collected along two streams in Victoria, Australia, and the effect of sampling density was assessed by subsampling from this dataset with precision related to the number of sites assessed per reach length and the intensity of the sampling at each site. The sampling scheme to achieve a given precision is shown to depend on the monitoring objective. In particular, three objectives were considered: (1) making a baseline assessment of current condition; (2) change detection; and (3) detection of a critical threshold in condition. Change detection is shown to be more demanding than assessing baseline condition with additional sampling effort required to achieve the same precision. Sampling to detect a critical threshold depends on nominating acceptable values of Type I and II error and the size of the effect to be detected. Copyright © 2006 John Wiley & Sons, Ltd.     

Temperature control of buildings by adobe wall design

The adobe house developed in the hot arid climate of the American Southwest has the virtue of being cool in the day and warm in the night. The adobe wall acts as a filter giving nearly a 12-hr phase lag in the outside temperature oscillation. However, on reaching the inside, the oscillation suffers a strong attenuation in amplitude. In a previous paper it was shown that if the resistivity of the wall could be varied in a certain way from outside to inside, thenthe attenuation would be considerably reduced. In this paper a formula is given for the minimum possible attenuation under given design restrictions. Then it is shown how to make an optimum wall by suitably proportioning two or three layers of different materials. Numerical illustrations are given.     

A simple design method for the Trombe wall

A simple analytical model of the Trombe wall is considered in which all the various parameters affecting the wall performance can be analyzed. Several design criteria for optimizing the wall performance are considered, and comparisons with previous methods are given.     

Long-term outcome of a prospective randomized trial of conversion from cyclosporine to azathioprine treatment one year after renal transplantation

BACKGROUND: Since the introduction of cyclosporine (CsA), 1-year renal allograft survival has improved, but concern persists about the long-term adverse effects of CsA, especially with respect to renal function and blood pressure. This randomized controlled trial was set up to establish whether withdrawal of CsA would alter long-term outcome. METHODS: Adult patients who, at 1 year after renal transplantation, had a stable serum creatinine of less than 300 micromol/L and who had not had acute rejection within the last 6 months were eligible for entry. Patients were randomized either to continue on CsA (n=114) or to stop CsA and start azathioprine (Aza, n=102). All patients remained on prednisolone. Median follow-up was 93 months after transplantation (range: 52-133 months). RESULTS: There was no significant difference in actuarial 10-year patient or graft survival (Kaplan-Meier), despite an increased incidence of acute rejection within the first few months after conversion. Median serum creatinine was lower in the Aza group (Aza: 119 micromol/L; CsA. 153 micromol/L at 5 years after randomization, P=0.0002). The requirement for antihypertensive treatment was also reduced after conversion to Aza; 75% of patients required antihypertensive treatment at the start of the study, decreasing to 55% from 1 year after randomization in the Aza group and increasing to >80% in the CsA group (55% (Aza) and 84% (CsA) at 5 years after randomization, P<0.005). CONCLUSIONS: Conversion from CsA to Aza at 1 year after renal transplantation results in improvement in both blood pressure control and renal allograft function, and is not associated with significant adverse effects on long-term patient or graft survival.     

SODA: A new method of in-scene atmospheric water vapor estimation and post-flight spectral recalibration for hyperspectral sensors: Application to the HyMap sensor at two locations

A new method of estimating per-pixel atmospheric column water vapor (ACWV) and potential differences in the reported band center wavelengths of the HyMap sensor has been developed. The new method uses variations of a second order derivative algorithm (SODA) to assess the impact of atmospheric residual features on calculated surface reflectance spectra after atmospheric compensation. The SODA method provides an alternative to the current band ratio techniques of ACWV estimation and also allows the same form of algorithm to be used for the estimation of possible band shifts. A comparison of in-situ measured surface reflectance at two field sites in Western Australia demonstrates improvement in the resulting spectra when post-flight updates are made to the reported HyMap band center wavelengths and applied during the atmospheric compensation process. The same SODA methodology was varied to estimate the ACWV on a per-pixel basis and found to significantly reduce the appearance of the underlying surface structure on the resulting ACWV images as well as improve the overall accuracy of the estimation. The ACWV estimated from the HyMap imagery at the two field sites was found to agree with in-situ atmospheric ACWV measurements to within 2% and represented a two fold increase in accuracy over a 3 band ratio Continuum Interpolated Band Ratio (CIBR) technique of ACWV estimation.     

A distributed problem‐solving framework for probabilistic software effort estimation

Distributed problem‐solving (DPS) systems use a framework of human organizational notions and principles of intelligent systems to solve complex problems. Human organizational notions are used to decompose a complex problem into sub‐problems that can be solved using intelligent systems. The solutions of these sub‐problems are combined to solve the original complex problem. In this paper, we propose a DPS system for probabilistic estimation of software development effort. Using a real‐world software engineering dataset, we compare the performance of the DPS system with a neural network (NN) and show that the performance of the DPS system is equal to or better than that of the NN with the additional benefits of modularity, probabilistic estimates, greater interpretability, flexibility and capability to handle incomplete input data.     

Issues in environmental impact assessment in victoria: What has scoresby taught us?

Abstract

The recent environmental assessment of major freeway and public transport proposals for the Scoresby Transport Corridor in Melbourne has highlighted deficiencies in processes and methodologies. The paper discusses strategic environmental assessment procedures and argues that its early application has the potential to overcome some of the difficulties identified and detailed here.     

Adaptation of the liquid chromatograph as a micro-reactor; immobilised lactase kinetics

A catalytic, micro-reactor system has been developed using a modified liquid chromatograph with an ultraviolet spectrophotometer detector. The continuous flow, micro-reactor method has been adapted to the measurement of the activity of enzyme catalysts immobilised on porous glass beads. The system offers advantages over other systems in terms of convenience and provisions for steady-state analysis and control. The speed and ease of obtaining reproducible data make it feasible to study the efficacy of immobilisation techniques systematically and to explore liquid chromatographic reactor methods further. The kinetic data obtained were compatible with those found with other methods for the hydrolysis of o-nitrophenyl-β-D-galactopyranoside with immobilised lactase from the fungus Aspergillus niger.