A state-contingent production approach to principal-agent problems with an application to point-source pollution control

Two basic representations of principal-agent relationships, the 'state-space' and 'parameterized distribution' formulations, have emerged. Although the state-space formulation appears more natural, analytical studies using this formulation have had limited success. This paper develops a state-space formulation of the moral-hazard problem using a general representation of production under uncertainty. A closed-form solution for the agency-cost problem is derived. Comparative-static results are deduced. Next we solve the principal's problem of selecting the optimal output given the agency-cost function. The analysis is applied to the problem of point-source pollution control. (C) 1998 Published by Elsevier Science S.A. All rights reserved.

Finite element modelling of temperature gradient driven rock alteration and mineralization in porous rock masses

We present finite element simulations of temperature gradient driven rock alteration and mineralization in fluid saturated porous rock masses. In particular, we explore the significance of production/annihilation terms in the mass balance equations and the dependence of the spatial patterns of rock alteration upon the ratio of the roll over time of large scale convection cells to the relaxation time of the chemical reactions. Special concepts such as the gradient reaction criterion or rock alteration index (RAI) are discussed in light of the present, more general theory. In order to validate the finite element simulation, we derive an analytical solution for the rock alteration index of a benchmark problem on a two-dimensional rectangular domain. Since the geometry and boundary conditions of the benchmark problem can be easily and exactly modelled, the analytical solution is also useful for validating other numerical methods, such as the finite difference method and the boundary element method, when they are used to dear with this kind of problem. Finally, the potential of the theory is illustrated by means of finite element studies related to coupled flow problems in materially homogeneous and inhomogeneous porous rock masses. (C) 1998 Elsevier Science S.A. All rights reserved.

A case-control study of employment status and mortality in a cohort of Australian youth

Recent studies have demonstrated a link in young populations between unemployment and ill health. The purpose of this study is to correlate mortality with employment status in two cohorts of young Australian males, aged 17-25 years, from 1984 to 1988. Two youth cohorts consisting of an initially unemployed sample (n = 1424 males) and a population sample (n = 4573 males), were surveyed annually throughout the study period. Those lost to follow-up during the survey period were matched with death registries across Australia. Employment status was determined from weekly diaries and death certificates and was designated as: employed or student; unemployed; not in the work force (excluding students). Conditional logistic regression, using age- and cohort- matched cases (deaths) and controls (alive), was used to estimate the odds ratio (OR) of dying with regard to employment status, taking into account potential confounders such as ethnicity, aboriginality, educational attainment, pre-existing health problems, socio-economic status of parents, and other factors. Twenty three male survey respondents were positively matched to death registry records. Compared to those employed or students (referent group), significantly elevated ORs were found to be associated with neither being in the workforce nor a student for all cause, external cause, and external cause mortality other than suicide. Odds ratios were adjusted for age, survey cohort, ethnicity, pre-existing physical and mental health status, education level, and socio-economic status of parent(s). A statistically significant increasing linear trend in odds ratios of male mortality for most cause groups was found across the employment categories, from those employed or student (lowest ORs), through those unemployed; to those not in the workforce (highest ORs). Suicide was higher, but not statistically significantly, in those unemployed or not in the workforce. Suicide also was associated, though not significantly, with the respondent not living with their parents when they were 14 years of age. No association was found between mortality and past unemployment experience, as measured by length of time spent unemployed, or the number of spells of unemployment experienced during the survey. The results of this study underscore the elevated risk to survival in young males as a consequence of being neither employed nor a student. (C) 1999 Elsevier Science Ltd. All rights reserved.

A comparison of three therapy methods for children with different types of developmental phonological disorder

Treatment case studies of three children whose speech was characterized by non-developmental errors are described. Three therapy methods were trialed with each child: phonological contrast; core vocabulary and PROMPT. The accuracy and intelligibility of the children's connected speech improved throughout: the course of the programme. Intervention that focused on teaching a rule about the contrastive use of phonemes was most successful for a child who consistently made non-developmental errors. Children making inconsistent errors received most benefit from the core vocabulary approach that markedly enhanced consistency of production. However, once consistency was established, one child benefited from phonological contrast therapy. While the results of the study should be interpreted with caution due to the small sample size and the cumulative effects of intervention, the findings suggest that different parts of a child's phonological and phonetic system may respond to various types of treatment approaches that target different aspects of speech production. The implication drawn is that just as no single treatment approach is appropriate for all children with disordered phonology, management of some children may involve selecting and sequencing a range of different approaches.

Separation and hedging results with state-contingent production

A state-contingent model of production under uncertainty is developed and compared with more traditional models of production under uncertainty. Producer behaviour with both production and price risk, in the presence and in the absence of futures and forward markets, is analysed in this state-contingent framework. Conditions for the optimal hedge to be positive or negative are derived. We also show that, under plausible conditions, a risk-averse producer facing price uncertainty and the ability to hedge price risk will never willingly adopt a nonstochastic technology. New separation results, which hold in the presence of both price and production risk, are then developed. These separation results generalize Townsend's spanning results by reducing the number of necessary forward markets by one.

Forecasting regional crop production using SOI phases: an example for the Australian peanut industry

Using peanuts as an example, a generic methodology is presented to forward-estimate regional crop production and associated climatic risks based on phases of the Southern Oscillation Index (SOI). Yield fluctuations caused by a highly variable rainfall environment are of concern to peanut processing and marketing bodies. The industry could profitably use forecasts of likely production to adjust their operations strategically. Significant, physically based lag-relationships exist between an index of ocean/atmosphere El Nino/Southern Oscillation phenomenon and future rainfall in Australia and elsewhere. Combining knowledge of SOI phases in November and December with output from a dynamic simulation model allows the derivation of yield probability distributions based on historic rainfall data. This information is available shortly after planting a crop and at least 3-5 months prior to harvest. The study shows that in years when the November-December SOI phase is positive there is an 80% chance of exceeding average district yields. Conversely, in years when the November-December SOI phase is either negative or rapidly falling there is only a 5% chance of exceeding average district yields, but a 95% chance of below average yields. This information allows the industry to adjust strategically for the expected volume of production. The study shows that simulation models can enhance SOI signals contained in rainfall distributions by discriminating between useful and damaging rainfall events. The methodology can be applied to other industries and regions.

Notes on market failure and the Paretian (Kaldor-Hicks) relevance and irrelevance of unfavourable externalities

The following are notes that have been distributed by me over the last few years to students in Environmental Economics at The University of Queensland. They give particular attention to whether externalities are Pareto or Kaldor-Hicks relevant from a policy point of view. Externalities are Kaldor-Hicks or Pareto irrelevant if no change is possible for which gainers could compensate losers. Both absolute and marginal externalities may be Kaldor-Hicks relevant. Infra-marginal negative externalities are often, but not always, Kaldor-Hicks irrelevant. There are at least two cases where such externalities can be relevant. First, the absolute impact of the negative externality may be so great that the source of the externality should be eliminated. Secondly, if the externality arises from production, its nature may depend on the type of production technique adopted. Although for the technique adopted, an infra-marginal negative externality occurs. That is Paretian irrelevant given that choice of this technique is the only available possibility, alternative techniques may actually be available in practice. Some of these may generate even smaller total external effects and be socially preferable. Both cases are outlined and illustrated in these notes. The analysis reveals the dangers of relying on marginalism for deciding on environmental policy. Total (external) effects are often of great social and economic importance and appropriate social choices cannot be made on the basis of marginalism alone.

Formation of cumulenes, triple-bonded, and related compounds by flash vacuum thermolysis of five-membered heterocycles

Flash vacuum thermolysis of a large variety of heterocyclic compounds is a useful means of production of ketenes, ketenimines, thioketenes, allenes, iminopropadienones, bis(imino)propadienes, iminopropadienethiones, carbodiimides, isothiocyanates, acetylenes, fulminic acid, nitrile imines and nitrile ylides, nitriles, cyanamides, cyanates, and other compounds, often in preparatively useful yields.

Clinical supervision in four mental health professions: A review of the evidence

This paper examines a range of theoretical issues and the empirical evidence relating to clinical supervision in four mental health professions, namely clinical psychology, occupational therapy, social work, and speech pathology. Despite the widespread acceptance of the value of supervision among practitioners and the large quantity of literature on the topic, there is very little empirical evidence in this area. It is not clear whether supervision actually produces a change in clinician behaviour, nor whether it produces benefits in terms of client outcomes. To date, there is insufficient evidence to demonstrate which styles of supervision are most beneficial for particular types of staff, in terms of their level of experience or learning style. The data suggest that directive forms of supervision, rather than unstructured approaches, are preferred by relatively inexperienced practitioners, and that experienced clinicians also value direct supervision methods when learning new skills or dealing with complex or crisis situations. The available evidence suggests that supervisors typically receive little training in supervision methods. However, to date, we have little information to guide us as to the most effective ways of training supervisors. While acknowledging the urgent need for research, the paper concludes that supervision is likely to form a valuable component of professional development for mental health professionals.

Randomised controlled trial of telemedicine for new neurological outpatient referrals

Objective-To test the hypothesis that telemedicine for new patient referrals to neurological outpatients is as efficient and acceptable as conventional face to face consultation. Methods-A randomised controlled trial between two groups: face to face (FF) and telemedicine (TM). This study was carried out between a neurological centre and outlying clinics at two distant hospitals linked by identical medium cost commercial interactive video conferencing equipment with ISDN lines transmitting information at 384 kbits/s. The same two neurologists carried out both arms of the study. Of the 168 patients who were suitable for the study, 86 were randomised into the telemedicine group and 82 into the face to face group. Outcome measures were (I) consultation process: (a) number of investigations; (b) number of drugs prescribed; (c) number of patient reviews and (2) patient satisfaction: (a) confidence in consultation; (b) technical aspects of consultation; (c) aspects surrounding confidentiality. Diagnostic categories were also measured to check equivalence between the groups: these were structural neurological, structural non-neurological, nonstructural, and uncertain. Results-Diagnostic categories were similar (p>0.5) between the two groups. Patients in the telemedicine group had significantly more investigations (p=0.001). There was no difference in the number of drugs prescribed (p>0.5). Patients were generally satisfied with both types of consultation process except for concerns about confidentiality and embarrassment in the telemedicine group (p=0.017 and p=0.005 respectively). Conclusion-Telemedicine for new neurological outpatients is possible and feasible but generates more investigations and is less well accepted than face to face examination.

A decision support system for selecting sanitation systems in developing countries

Due to the socio-economic inhomogeneity of communities in developing countries, the selection of sanitation systems is a complex task. To assist planners and communities in assessing the suitability of alternatives, the decision support system SANEX™ was developed. SANEX™ evaluates alternatives in two steps. First, Conjunctive Elimination, based on 20 mainly technical criteria, is used to screen feasible alternatives. Subsequently, a model derived from Multiattribute Utility Technique (MAUT) uses technical, socio-cultural and institutional criteria to compare the remaining alternatives with regard to their implementability and sustainability. This paper presents the SANEX™ algorithm, examples of its application in practice, and results obtained from field testing.

Economic and environmental impacts of pollution control in a system of environment and economic interdependence

The importance of the rate of change of the pollution stock in determining the damage to the environment has been an issue of increasing concern in the literature. This paper uses a three-sector (economy, population and environment), non-linear, discrete time, calibrated model to examine pollution control. The model explicitly links economic growth to the health of the environment. The stock of natural resources is affected by the rate of pollution flows, through their impact on the regenerative capacity of the natural resource stock. This can shed useful insights into pollution control strategies, particularly in developing countries where environmental resources are crucial for production in many sectors of the economy. Simulation exercises suggested that, under plausible assumptions, it is possible to reverse undesirable transient dynamics through pollution control expenditure, but this is dependent upon the strategies used for control. The best strategy is to spend money fostering the development of production technologies that reduce pollution rather than spending money dealing with the effects of the pollution flow into the environment. (C) 2001 Elsevier Science Ltd. All rights reserved.

Patterns of change and stability in the gender division of household labour in Australia, 1986-1997

Recent research in Australia and overseas has suggested that we are witnessing a convergence of men's and women's time on domestic labour activities. But there is disagreement about whether this is due to women reducing their time on housework or men increasing their time on housework. This article addresses these issues using national survey data collected in Australia in 1986, 1993 and 1997. The results show some changes in the proportional responsibilities of men and women in the home with men reporting a greater share of traditional indoor activities. But overall both men and women are spending less time on housework. In particular, women's time on housework has declined by six hours per week since 1986. Hence, while the gender gap between men's and women's involvement in the home is getting smaller, it is not the result of men increasing their share of the load, but is due to the large decline in women's time spent on domestic labour. There is also evidence of change in the relationship. between paid and unpaid work for women. Women's hours of,paid labour had a greater impact on their involvement in domestic labour in 1997 compared to a decade earlier. The article concludes that women's increased labour force involvement in combination with changing patterns and styles, of consumption is leading to some changes in the gender-division:of household labour, but not in the direction anticipated by earlier commentators on the domestic division of labour.

Comparative sperm ultrastructure of the Baikalian endemic prosobranch gastropods

Mature euspermatozoan ultrastructure is described for seven species of the rissooidean family Baicaliidae (endemic to Lake Baikal, Russia)-Liobaicalia stiedae, Teratobaikalia ciliata, T. macrostoma, Baicalia carinata, Pseudobaikalia pulla, Maackia bythiniopsis, M. variesculpta, and M. herderiana. For comparison with these species and previously investigated Rissooidea, two species of the Lake Baikal endemic genus Benedictia (B. cf. fragilis and B. baicalensis; Hydrobiidae: Benedictiinae of some authors, Benedictiidae of other authors) in addition to Lithoglyphus naticoides (Hydrobiidae: Lithoglyphinae) and Bythinella austriaca (Hydrobiidae: Bythinellinae) were also investigated. Paraspermatozoa were not observed in any of the species examined, supporting the view that these cells are probably absent in the Rissooidea. In general, the euspermatozoa of all species examined resemble those of many other caenogastropods (basally invaginated acrosomal vesicle, mid-piece with 7-13 helical mitochondria, an annulus, glycogen piece with nine peri-axonemal tracts of granules). However, the presence of a completely flattened acrosomal vesicle and a specialized peri-axonemal membranous sheath (a scroll-like arrangement of 4-6 double membranes) at the termination of the mid-piece, clearly indicates a close relationship between the Baicaliidae and other rissooidean families possessing these features (Bithyniidae, Hydrobiidae, Pyrgulidae, and Stenothyridae). Euspermatozoa of Benedictia, Lithoglyphus, Bythinella, and Pyrgula all have a solid nucleus, which exhibits a short, posterior invagination (housing the centriolar complex and proximal portion of the axoneme). Among the Rissooidea, this form of nucleus is known to occur in the Bithyniidae, Hydrobiidae, Truncatellidae, Pyrgulidae, Iravadiidae, Pomatiopsidae, and Stenothyridae. In contrast, the euspermatozoa of the Baicaliidae all have a long, tubular nucleus, housing not only the centriolar derivative, but also a substantial portion of the axoneme. Among the Rissooidea, a tubular nuclear morphology has previously been seen in the Rissoidae, which could support the view, based on anatomical grounds, that the Baicaliidae may have arisen from a different ancestral source than the Hydrobiidae. However, the two styles of nuclear morphology (short, solid versus long, tubular) occur widely within the Caenogastropoda, and sometimes both within a single family, thereby reducing the phylogenetic importance of nuclear differences within the Rissooidea. More significantly, the occurrence of the highly unusual membranous sheath within the mid-piece region in the Baicaliidae appears to tie this family firmly to the Bithyniidae + Hydrobiidae + Stenothyridae + Pyrgulidae assemblage. Eusperm features of Benedictia spp. strongly resemble those of hydrobiids and bithyniids, and neither support recognition of a distinct family Benedictiidae (at best this is a subfamily of Hydrobiidae) nor any close connection with the hydrobiid subfamily Lithoglyphinae.

The egalitarian leader: A comparison of leadership in Australia and New Zealand

This article compares leadership in Australia and New Zealand based on data collected as a part of the GLOBE (Global Leadership and Organizational Behavior effectiveness) 62-nation culture and leadership project. Exploratory and confirmatory factor analyses were used to demonstrate that etic (universal) dimensions of 'Charismatic' and 'Self-Protective' leadership are evident in both cultures, but that the dimensions have emic (local) culturally determined manifestations. These emic manifestations were stronger in New Zealand than in Australia. Leadership effectiveness incorporated the negative emic dimension of 'Bureaucratic' leadership (both countries), and the positive emic dimension of 'Egalitarian leadership' in Australia and 'Team leadership' in New Zealand. Both models of leadership nonetheless represent styles of leadership based on egalitarian principles.