Equity in regional service provision

Most transportation agencies stipulate that an important planning goal is to provide equitable and just public transport services. However, who is to be served and the type of service that should be provided has been ambiguous. This paper develops a methodology for examining equity in the provision of public transportation services. An approach for identifying areas in need of public transport is developed based upon the use of socio-demographic and economic information. Public transport need is then related to levels of access to service. This approach makes it possible to establish the degree to which public transport services may be considered equitable in relation to need and suitable access. A detailed analysis of the southeast Queensland region of Australia illustrates how this approach may be used to inform public transport decision making.

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.

Efficient simulation of a Tandem Jackson Network

The two-node tandem Jackson network serves as a convenient reference model for the analysis and testing of different methodologies and techniques in rare event simulation. In this paper we consider a new approach to efficiently estimate the probability that the content of the second buffer exceeds some high level L before it becomes empty, starting from a given state. The approach is based on a Markov additive process representation of the buffer processes, leading to an exponential change of measure to be used in an importance sampling procedure. Unlike changes of measures proposed and studied in recent literature, the one derived here is a function of the content of the first buffer. We prove that when the first buffer is finite, this method yields asymptotically efficient simulation for any set of arrival and service rates. In fact, the relative error is bounded independent of the level L; a new result which is not established for any other known method. When the first buffer is infinite, we propose a natural extension of the exponential change of measure for the finite buffer case. In this case, the relative error is shown to be bounded (independent of L) only when the second server is the bottleneck; a result which is known to hold for some other methods derived through large deviations analysis. When the first server is the bottleneck, experimental results using our method seem to suggest that the relative error is bounded linearly in L.

Body size and latitudinal gradients in regional diversity of New World birds

Axe latitudinal gradients in regional diversity random or biased with respect to body size? Using data for the New World avifauna, I show that the slope of the increase in regional species richness from the Arctic to the equator is not independent of body size. The increase is steepest among small and medium-sized species, and shallowest among the largest species. This is reflected in latitudinal variation in the shape of frequency distributions of body sizes in regional subsets of the New World avifauna. Because species are added disproportionately in small and medium size classes towards low latitudes, distributions become less widely spread along the body size axis than expected from the number of species. These patterns suggest an interaction between the effects of latitude and body size on species richness, implying that mechanisms which vary with both latitude and body size may be important determinants of high tropical diversity in New World birds.

Determinants of tissue Doppler measures of regional diastolic function during dobutamine stress echocardiography

Background Diastolic dysfunction induced by ischemia may alter transmitral blood flow, but this reflects global ventricular function, and pseudonormalization may occur with increased preload. Tissue Doppler may assess regional diastolic function and is relatively load-independent, but limited data exist regarding its application to stress testing. We sought to examine the stress response of regional diastolic parameters to dobutomine echocardiography (DbE). Methods Sixty-three patients underwent study with DbE: 20 with low probability of coronary artery disease (CAD) and 43 with CAD who underwent angiography. A standard DbE protocol was used, and segments were categorized as ischemic, scar, or normal. Color tissue Doppler was acquired at baseline and peak stress, and waveforms in the basal and mid segments were used to measure early filling (Em), late filling (Am), and E deceleration time. Significant CAD was defined by stenoses >50% vessel diameter. Results Diastolic parameters had limited feasibility because of merging of Em and Am waves at high heart rates and limited reproducibility. Nonetheless, compared with normal segments, segments subtended with significant stenoses showed a lower Em velocity at rest (6.2 +/- 2.6 cm/s vs 4.8 +/- 2.2 cm/s, P < .0001) and peak (7.5 +/- 4.2 cm/s vs 5.1 +/- 3.6 cm/s, P < .0001), Abnormal segments also showed a shorter E deceleration time (51 +/- 27 ms vs 41 +/- 27 ms, P = .0001) at base and peak. No changes were documented in Am. The same pattern was seen with segments identified as ischemic with wall motion score. However, in the absence of ischemia, segments of patients with left ventricular hypertrophy showed a lower Em velocity, with blunted Em responses to stress. Conclusion Regional diastolic function is sensitive to ischemia. However, a number of practical limitations limit the applicability of diastolic parameters for the quantification of stress echocardiography.

Automated regional myocardial displacement for facilitating the interpretation of dobutamine echocardiography

Quantification of stress echocardiography may overcome the training requirements and subjective nature of visual wall motion score (WMS) assessment, but quantitative approaches may be difficult to apply and require significant time for image processing. The integral of long-axis myocardial velocity is displacement, which may be represented as a color map over the left ventricular myocardium. This study was designed to explore the feasibility and accuracy of measuring long-axis myocardial displacement, derived from tissue Doppler, for the detection of coronary artery disease (CAD) during dobutamine stress echocardiography (DBE). One hundred thirty patients underwent standard DBE, including 30 patients at low risk of CAD, 30 patients with normal coronary angiography (both groups studied to define normal ranges of displacement), and 70 patients who underwent coronary angiography in whom the accuracy of normal ranges was tested. Regional myocardial displacement was obtained by analysis of color tissue Doppler apical images acquired at peak stress. Displacement was compared with WMS, and with the presence of CAD by angiography. The analysis time was 3.2 +/- 1.5 minutes per patient. Segmental displacement was correlated with wall motion (normal 7.4 +/- 3.2 mm, ischemia 5.8 +/- 4.2 mm, viability 4.6 +/- 3.0 mm, scar 4.5 +/- 3.5 mm, p <0.001). Reversal of normal base-apex displacement was an insensitive (19%) but specific (90%) marker of CAD. The sum of displacements within each vascular territory had a sensitivity and specificity of 89% and 79%, respectively, for prediction of significant CAD, compared with 86% and 78%, respectively, for WMS (p = NS). The displacements in the basal segments had a sensitivity and specificity of 83% and 78%, respectively (p = NS). Regional myocardial displacement during DBE is feasible and offers a fast and accurate method for the diagnosis of CAD. (C),2002 by Excerpta Medica, Inc.

Resources for security and stability? The politics of regional cooperation on the Mekong, 1957-2001

This article tells about the relationship between resource politics and security in international relations. Using the Mekong River Basin as its case study, the article examines the place of resource and development issues in attempts to develop regional institutions. The question of whether a resource development regime with apparently low productivity in terms of technical output, but high levels of resilience and longevity, should be considered a failure or not, is considered. This question is examined within the broader context of Southeast Asian politics during the First, Second, and Third Indochina conflicts as well as the post-cold war era. The article argues that survival and a capacity to change to meet the challenges of extreme broader events are clear evidence of regime success. From this standpoint, the article explores ways in which the Mekong resource regime is linked to more general concerns for political security and stability and may in fact reflect political concerns for subregional neighborhood maintenance.

Intrinsic regional differences in androgen receptors and dihydrotestosterone metabolism in human preadipocytes

Androgens play an important role in regulating the central obesity that is a strong risk factor for cardiovascular disease and insulin resistance. This study confirms that androgen receptors are present in subcultured human preadipocytes, with androgen receptor gene expression and saturable specific dihydrotestosterone binding, dissociation constant 1.02 - 2.56 nM and maximal binding capacity 30.8 - 55.7 fmol/mg protein. There was an intrinsic regional difference in androgen receptor complement, with more androgen receptors in visceral than in subcutaneous preadipocytes. Dihydrotestosterone was metabolised by human preadipocytes, with more androstanediol produced by subcutaneous than visceral preadipocytes. While dihydrotestosterone metabolism was insufficient to explain the regional variation in androgen binding, both of these differences would reduce the androgen responsiveness of the subcutaneous preadipocytes compared with visceral preadipocytes. There were no gender differences in androgen binding or metabolism. While the direct effects of androgens on human PAS remain uncertain, these regional differences suggest that AR-mediated regulation of certain PA functions influences adipose tissue distribution.

Use of liquid phase adsorption for characterizing pore network connectivity in activated carbon

A simple percolation theory-based method for determination of the pore network connectivity using liquid phase adsorption isotherm data combined with a density functional theory (DFT)-based pore size distribution is presented in this article. The liquid phase adsorption experiments have been performed using eight different esters as adsorbates and microporous-mesoporous activated carbons Filtrasorb-400, Norit ROW 0.8 and Norit ROX 0.8 as adsorbents. The density functional theory (DFT)-based pore size distributions of the carbons were obtained using DFT analysis of argon adsorption data. The mean micropore network coordination numbers, Z, of the carbons were determined based on DR characteristic plots and fitted saturation capacities using percolation theory. Based on this method, the critical molecular sizes of the model compounds used in this study were also obtained. The incorporation of percolation concepts in the prediction of multicomponent adsorption equilibria is also investigated, and found to improve the performance of the ideal adsorbed solution theory (IAST) model for the large molecules utilized in this study. (C) 2002 Elsevier Science B.V. All rights reserved.