On the equivalence of weighted Country-Product-Dummy (CPD) Method and the Rao-System for multilateral price comparisons

The country-product-dummy (CPD) method, originally proposed in Summers (1973), has recently been revisited in its weighted formulation to handle a variety of data related situations (Rao and Timmer, 2000, 2003; Heravi et al., 2001; Rao, 2001; Aten and Menezes, 2002; Heston and Aten, 2002; Deaton et al., 2004). The CPD method is also increasingly being used in the context of hedonic modelling instead of its original purpose of filling holes in Summers (1973). However, the CPD method is seen, among practitioners, as a black box due to its regression formulation. The main objective of the paper is to establish equivalence of purchasing power parities and international prices derived from the application of the weighted-CPD method with those arising out of the Rao-system for multilateral comparisons. A major implication of this result is that the weighted-CPD method would then be a natural method of aggregation at all levels of aggregation within the context of international comparisons.

The metaphysical equivalence of three and four dimensionalism

I argue that two competing accounts of persistence, three and four dimensionalism, are in fact metaphysically equivalent. I begin by clearly defining three and four dimensionalism, and then I show that the two theories are inter-translatable and equally simple. Through consideration of a number of different cases where intuitions about persistence are contradictory, I then go on to show that both theories describe these cases in the same manner. Further consideration of some empirical issues arising from the theory of special relativity lead me to conclude that the two theories are equally explanatory, and thus finally that they are metaphysically equivalent.

Equivalence of the Peleg, Pilosof and Singh-Kulshrestha models for water absorption in food

The similarity between the Peleg, Pilosof –Boquet–Batholomai and Singh–Kulshrestha models was investigated using the hydration behaviours of whey protein concentrate, wheat starch and whey protein isolate at 30 °C in 100% relative humidity. The three models were shown to be mathematically the same within experimental variations, and they yielded parameters that are related. The models, in their linear and original forms, were suitable (r2 > 0.98) in describing the sorption behaviours of the samples, and are sensitive to the length of the sorption segment used in the computation. The whey proteins absorbed more moisture than the wheat starch, and the isolate exhibited a higher sorptive ability than the concentrate.

The consumption of alcohol by Australian adolescents: A comparison of revenue and expenditure

Aims: To estimate (i) Australian government taxation revenue collected from the consumption of alcohol by adolescents and (ii) the amount spent by the government on interventions aimed at educating adolescents about the potential dangers of alcohol use. Design: Secondary data analysis. Setting: Australia. Findings: Australian adolescents (aged between 12 and 17 years, inclusive) spent approximately $217 million on alcoholic beverages in 2002, netting the Australian government approximately $112 million in tax revenue. This resulted in an average of $195 earned in tax per adolescent drinker. It is estimated that the Government spent approximately $17 million on adolescent drinking interventions in 2002, equating to an expenditure of about $10.51 per adolescent on the delivery of alcohol interventions. For every dollar spent on alcohol interventions aimed at adolescents, it is estimated that the government receives around $7 in alcohol tax revenue. Conclusions: A substantial disparity exists between the amount of tax revenue received by the Australian Government from adolescent drinkers and the overall amount spent in attempting to prevent and relieve some of the problems associated with adolescent problem drinking. (c) 2006 Elsevier Ltd. All rights reserved.

Health-related quality of life in Australian children with asthma: lessons for the cross-cultural use of quality of life instruments

The development of Australian forms of the Childhood Asthma Questionnaires (CAQs) is reported. Focus group methods and psychometric analyses were used to establish the conceptual, semantic and technical equivalence of these forms with the UK versions. Both versions also provide for data collection from non-asthmatic youngsters. The internal consistency was found to be acceptable (Cronbach's alpha 0.52-0.90) and the health-related quality of life (HRQoL) scores were found to vary with asthma severity (p < 0.05). Comparison with the UK data revealed that the non-asthmatic scores were higher for Australian than British children (p < 0.001) but that the scores for children with asthma did not differ between the two countries. It was only In the Australian sample that the group with asthma reported impaired HRQoL when compared to their healthy peers. These findings were interpreted in the context of cultural expectations of life quality and conclusions are presented regarding the importance of the gap between experience and expectations. The difficulties raised by the developmental and cultural issues inherent in paediatric HRQoL research were discussed. Qual. Life Res. 7:409-419 (C) 1998 Kluwer Academic Publishers

Functional assessment and care of children with neurodevelopmental disabilities

Objectives: To determine the relationship between pediatric assessment scores and ratings by parents and teachers regarding the amount of assistance required to complete basic activities of daily living; and to examine the relationship among scores for three commonly used pediatric assessments. Design: Prospective correlational study. 205 children with developmental disabilities. The children ranged in age from 11 to 87 mo and included 72 females and 133 males of diverse socioeconomic and ethnic backgrounds. The children were evaluated by using the Battelle Developmental Inventory Screening Test, Vineland Adaptive Behavior Scales, Functional Independence Measure for Children (WeeFIM(TM) instrument), and the Amount of Assistance Questionnaire, Results: The test-retest reliability coefficients for items on the Amount of Assistance Questionnaire were found to range from 0.82 to 0.97. Correlations among subscale scores and amount of assistance ratings were highest for the WeeFIM instrument and Battelle Developmental Inventory Screening Test. The highest correlation was between WeeFIM total rating and total amount of assistance rating (r = 0.91). Conclusion: Total WeeFIM instrument ratings and severity of disability were the best predictors of amount of assistance ratings provided by parents and teachers.

Response to price and production risk: The case of Australian wheat

A model of Australian wheat grower supply response was specified under the constraints of price and yield uncertainty, risk aversion, partial adjustment, and quadratic costs. The model was solved to obtain area planted. The results of estimation indicate that risk arising from prices and climate have had a significant influence on producer decision making. The coefficient of relative risk aversion and short-run and long-run elasticities of supply with respect to price were calculated. Wheat growers' risk premium, expected at the start of the season for exposed price and yield risk, was 2.8 percent of revenue or 10.4 percent of profit as measured by producer surplus. (C) 2000 John Wiley & Sons, Inc.

Quasistationarity of continuous-time Markov chains with positive drift

We shall study continuous-time Markov chains on the nonnegative integers which are both irreducible and transient, and which exhibit discernible stationarity before drift to infinity sets in. We will show how this 'quasi' stationary behaviour can be modelled using a limiting conditional distribution: specifically, the limiting state probabilities conditional on not having left 0 for the last time. By way of a dual chain, obtained by killing the original process on last exit from 0, we invoke the theory of quasistationarity for absorbing Markov chains. We prove that the conditioned state probabilities of the original chain are equal to the state probabilities of its dual conditioned on non-absorption, thus allowing us to establish the simultaneous existence and then equivalence, of their limiting conditional distributions. Although a limiting conditional distribution for the dual chain is always a quasistationary distribution in the usual sense, a similar statement is not possible for the original chain.

Quantum measurement and stochastic processes in mesoscopic conductors

In quantum measurement theory it is necessary to show how a, quantum source conditions a classical stochastic record of measured results. We discuss mesoscopic conductance using quantum stochastic calculus to elucidate the quantum nature of the measurement taking place in these systems. To illustrate the method we derive the current fluctuations in a two terminal mesoscopic circuit with two tunnel barriers containing a single quasi bound state on the well. The method enables us to focus on either the incoming/ outgoing Fermi fields in the leads, or on the irreversible dynamics of the well state itself. We show an equivalence between the approach of Buttiker and the Fermi quantum stochastic calculus for mesoscopic systems.

Similitude applied to centrifugal scaling of unsaturated flow

Centrifuge experiments modeling single-phase flow in prototype porous media typically use the same porous medium and permeant. Then, well-known scaling laws are used to transfer the results to the prototype. More general scaling laws that relax these restrictions are presented. For permeants that are immiscible with an accompanying gas phase, model-prototype (i.e., centrifuge model experiment-target system) scaling is demonstrated. Scaling is shown to be feasible for Miller-similar (or geometrically similar) media. Scalings are presented for a more, general class, Lisle-similar media, based on the equivalence mapping of Richards' equation onto itself. Whereas model-prototype scaling of Miller-similar media can be realized easily for arbitrary boundary conditions, Lisle-similarity in a finite length medium generally, but not always, involves a mapping to a moving boundary problem. An exception occurs for redistribution in Lisle-similar porous media, which is shown to map to spatially fixed boundary conditions. Complete model-prototype scalings for this example are derived.

Hybrid auctions

In this paper we analyze a hybrid auction that combines a first-price and a Vickrey auction. We show that this auction may generate more expected revenue than a standard first-price auction. (C) 2002 Elsevier Science B.V. All rights reserved.

Scope for further analytical solutions for constant flux infiltration into a semi-infinite soil profile or redistribution in a finite soil profile

[1] We attempt to generate new solutions for the moisture content form of the one-dimensional Richards' [1931] equation using the Lisle [1992] equivalence mapping. This mapping is used as no more general set of transformations exists for mapping the one-dimensional Richards' equation into itself. Starting from a given solution, the mapping has the potential to generate an infinite number of new solutions for a series of nonlinear diffusivity and hydraulic conductivity functions. We first seek new analytical solutions satisfying Richards' equation subject to a constant flux surface boundary condition for a semi-infinite dry soil, starting with the Burgers model. The first iteration produces an existing solution, while subsequent iterations are shown to endlessly reproduce this same solution. Next, we briefly consider the problem of redistribution in a finite-length soil. In this case, Lisle's equivalence mapping is generalized to account for arbitrary initial conditions. As was the case for infiltration, however, it is found that new analytical solutions are not generated using the equivalence mapping, although existing solutions are recovered.

Prediction of carbon monoxide in fires by conditional moment closure

Carbon monoxide is the chief killer in fires. Dangerous levels of CO can occur when reacting combustion gases are quenched by heat transfer, or by mixing of the fire plume in a cooled under- or overventilated upper layer. In this paper, carbon monoxide predictions for enclosure fires are modeled by the conditional moment closure (CMC) method and are compared with laboratory data. The modeled fire situation is a buoyant, turbulent, diffusion flame burning under a hood. The fire plume entrains fresh air, and the postflame gases are cooled considerably under the hood by conduction and radiation, emulating conditions which occur in enclosure fires and lead to the freezing of CO burnout. Predictions of CO in the cooled layer are presented in the context of a complete computational fluid dynamics solution of velocity, temperature, and major species concentrations. A range of underhood equivalence ratios, from rich to lean, are investigated. The CMC method predicts CO in very good agreement with data. In particular, CMC is able to correctly predict CO concentrations in lean cooled gases, showing its capability in conditions where reaction rates change considerably.

An equivalent algorithm for simulating thermal effects of magma intrusion problems in porous rocks

An equivalent algorithm is proposed to simulate thermal effects of the magma intrusion in geological systems, which are composed of porous rocks. Based on the physical and mathematical equivalence, the original magma solidification problem with a moving boundary between the rock and intruded magma is transformed into a new problem without the moving boundary but with a physically equivalent heat source. From the analysis of an ideal solidification model, the physically equivalent heat source has been determined in this paper. The major advantage in using the proposed equivalent algorithm is that the fixed finite element mesh with a variable integration time step can be employed to simulate the thermal effect of the intruded magma solidification using the conventional finite element method. The related numerical results have demonstrated the correctness and usefulness of the proposed equivalent algorithm for simulating the thermal effect of the intruded magma solidification in geological systems. (C) 2003 Elsevier B.V. All rights reserved.