The health watch case - control study of leukemia and benzene:the story so far

A case–control study nested in the Health Watch cohort of petroleum industry workers, investigated whether the excess of lymphohematopoetic cancers, identified among male members of the Health Watch cohort, was associated with benzene exposure. Cases of non-Hodgkin’s lymphoma (n=31),multiple myeloma (n=15), and leukemia (n=33)were identified between 1981 and 1999. Cases were age-matched to five controls. Exposure was retrospectively estimated for each occupational history using an algorithm in a relational database. Benzene exposure measurements, supplied by Australian petroleum companies, were used to estimate exposure for specific tasks. The tasks carried out within the job, the products handled, and the technology used,were identified from interviews with contemporary colleagues. More than half of the subjects started work after 1965 and had an average exposure period of 20 years. Exposure was low, 85% of the cumulative exposure estimates were<10 ppm years. Matched analyses showed that non-Hodgkin’s lymphoma and multiple myeloma were not associated with benzene exposure. Leukemia risk, however, was significantly increased for the subjects with greater than 16 ppm years cumulative exposure, odds ratio (OR) 51.9 (5.6–477) or with greater than 0.8 ppm intensity of highest exposed job. Cumulative exposures were similar to those found in comparable studies.The inclusion of occasional high exposures, for example, as a result of spillages, reduced the ORs, when the exposure was treated as either a continuous or a categorical variable. Our data demonstrate a strong association between leukemia and modest benzene exposure. The choice of cut-point and reference group has a marked effect on the ORs, but does not change the overall conclusions.

A distributed approach to global feedback control of multi-agent systems

This paper presents a distributed approach to global state feedback control of for multi-agent systems. The proposed solution is obtained from the construction of decentralised functional observers. The required local control signal is generated asymptotically using only corresponding local output information. It is shown that a complete distribution of the control of a decentralised system having N agents can be achieved upon the satisfaction of some necessary conditions, and that the resulting controller can emulate the performance of a global state feedback controller. A step-by-step design algorithm is given. Its simplicity and correctness are illustrated through a numerical example.

Eccentricity and hardness control in cold rolling mills with a dynamically constructed neural controller

The main objective of a steel strip rolling process is to produce high quality steel at a desired thickness.  Thickness reduction is the result of the speed difference between the incoming and the outgoing steel strip and the application of the large normal forces via the backup and the work rolls.  Gauge control of a cold rolled steel strip is achieved using the gaugemeter principle that works adequately for the input gauge changes and the strip hardness changes.  However, the compensation of some factors is problematic, for example, eccentricity of the backup rolls.  This cyclic eccentricity effect causes a gauge deviation, but more importantly, a signal is passed to the gap position control so to increase the eccentricity deviation.  Consequently, the required high product tolerances are severely limited by the presence of the roll eccentricity effects.
In this paper a direct model reference adaptive control (MRAC) scheme with dynamically constructed neural controller was used.  The aim here is to find the simplest controller structure capable of achieving an optimal performance.  The stability of the adaptive neural control scheme (i.e. the requirement of persistency of excitation and bounded learning rates) is addressed by using as the inputs to the reference model the plant's state variables.  In such a case, excitation is due to actual plant signals (states) affected by plant disturbances and noise.  In addition, a reference model in the form of a filter with a desired transfer function using Modulus Optimum design was used to ensure variance in the desired dynamic characteristics of the system.  The gradually decreasing learning rate employed by the neural controller in this paper is aimed at eliminating controller instability resulting from over-aggressive control.  The moving target problem (i.e. the difficulty of global neural networks to perfrom several separate computational tasks in closed -loop control) is addressed by the localized architecture of the controller.  The above control scheme and learning algorithm offers a method for automatic discovery of an efficient controller.
The resulting neural controller produces an excellent disturbance rejection in both cases of eccentricity and hardness disturbances, reducing the gauge deviation due to eccentricity disturbance from 33.36% to 4.57% on average, and the gauge deviation due to hardness disturbance from 12.59% to 2.08%.

Ownership structure and corporate performance : Australian evidence

This paper seeks to analyse the relationship between ownership structure and corporate performance for fifty firms listed on the Australian Stock Exchange during 2002-2003. The study initially tests a two equation model similar to that in the existing literature, but is distinguished from prior literature by subsequently reclassifying leverage. By categorising leverage as an endogenous variable, an examination of the relationship between ownership and performance is undertaken through ordinary least squares and two stage least squares analysis of a three equation econometric model. Interestingly, empirical results illustrate the fact that managerial ownership impacts negatively on firm performance which is consistent with the management entrenchment hypothesis.

Phytophthora cinnamomi and Australia’s biodiversity : impacts, predictions and progress towards control

Phytophthora cinnamomi continues to cause devastating disease in Australian native vegetation and consequently the disease is listed by the Federal Government as a process that is threatening Australia’s biodiversity. Although several advances have been made in our understanding of how this soil-borne pathogen interacts with plants and of how we may tackle it in natural systems, our ability to control the disease is limited. The pathogen occurs widely across Australia but the severity of its impact is most evident within ecological communities of the south-west and south-east of the country. A regional impact summary for all states and territories shows the pathogen to be the cause of serious disease in numerous species, a significant number of which are rare and threatened. Many genera of endemic taxa have a high proportion of susceptible species including the iconic genera Banksia, Epacris and Xanthorrhoea. Long-term studies in Victoria have shown limited but probably unsustainable recovery of susceptible vegetation, given current management practices. Management of the disease in conservation reserves is reliant on hygiene, the use of chemicals and restriction of access, and has had only limited effectiveness and not provided complete control. The deleterious impacts of the disease on faunal habitat are reasonably well documented and demonstrate loss of individual animal species and changes in population structure and species abundance. Few plant species are known to be resistant to P. cinnamomi; however, investigations over several years have discovered the mechanisms by which some plants are able to survive infection, including the activation of defence-related genes and signalling pathways, the reinforcement of cell walls and accumulation of toxic metabolites. Manipulation of resistance and resistance-related mechanisms may provide avenues for protection against disease in otherwise susceptible species. Despite the advances made in Phytophthora research in Australia during the past 40 years, there is still much to be done to give land managers the resources to combat this disease. Recent State and Federal initiatives offer the prospect of a growing and broader awareness of the disease and its associated impacts. However, awareness must be translated into action as time is running out for the large number of susceptible, and potentially susceptible, species within vulnerable Australian ecological communities.

Electrospun single-walled carbon nanotube/polyvinyl alcohol composite nanofibers : structure-property relationships

Polyvinyl alcohol (PVA) nanofibers and single-walled carbon nanotube (SWNT)/PVA composite nanofibers have been produced by electrospinning. An apparent increase in the PVA crystallinity with a concomitant change in its main crystalline phase and a reduction in the crystalline domain size were observed in the SWNT/PVA composite nanofibers, indicating the occurrence of a SWNT-induced nucleation crystallization of the PVA phase. Both the pure PVA and SWNT/PVA composite nanofibers were subjected to the following post-electrospinning treatments: (i) soaking in methanol to increase the PVA crystallinity, and (ii) cross-linking with glutaric dialdehyde to control the PVA morphology. Effects of the PVA morphology on the tensile properties of the resultant electrospun nanofibers were examined. Dynamic mechanical thermal analyses of both pure PVA and SWNT/PVA composite electrospun nanofibers indicated that SWNT–polymer interaction facilitated the formation of crystalline domains, which can be further enhanced by soaking the nanofiber in methanol and/or cross-linking the polymer with glutaric dialdehyde.

Calcineurin-Aα alpha activation enhances the structure and function of regenerating muscles after myotoxic injury

Calcineurin signaling is essential for successful muscle regeneration. Although calcineurin inhibition compromises muscle repair, it is not known whether calcineurin activation can enhance muscle repair after injury. Tibialis anterior (TA) muscles from adult wild-type (WT) and transgenic mice overexpressing the constitutively active calcineurin-Aα transgene under the control of the mitochondrial creatine kinase promoter (MCK-CnAα*) were injected with the myotoxic snake venom Notexin to destroy all muscle fibers. The TA muscle of the contralateral limb served as the uninjured control. Muscle structure was assessed at 5 and 9 days postinjury, and muscle function was tested in situ at 9 days postinjury. Calcineurin stimulation enhanced muscle regeneration and altered levels of myoregulatory factors (MRFs). Recovery of myofiber size and force-producing capacity was hastened in injured muscles of MCK-CnAα* mice compared with control. Myogenin levels were greater 5 days postinjury and myocyte enhancer factor 2a (MEF2a) expression was greater 9 days postinjury in muscles of MCK-CnAα* mice compared with WT mice. Higher MEF2a expression in regenerating muscles of MCK-CnAα* mice 9 days postinjury may be related to an increase of slow fiber genes. Calcineurin activation in uninjured and injured TA muscles slowed muscle contractile properties, reduced fatigability, and enhanced force recovery after 4 min of intermittent maximal stimulation. Therefore, calcineurin activation can confer structural and functional benefits to regenerating skeletal muscles, which may be mediated in part by differential expression of MRFs.

Intersection of autonomy and social control : negotiating teenage motherhood

Contrary to popular belief, teenage mothers are a declining proportion of birthing women; however they receive much negative public attention. Of particular public concern is the high cost of supporting teenage mothers, in terms of financial, health and welfare resources. Historically, the typical founding mother of white Australia was single, but post-war changes in the family structure incorporated the expectation that children be born into two-parent households with the male as the breadwinner. Policy changes in the seventies saw the introduction of the Sole Parents Pension which meant that many birthing teenage women could choose to keep their infants rather than have a clandestine adoption or an enforced marriage. The parenting practices of teenage mothers have been criticised for being less than optimal, and mother and child are reported as being disadvantaged cognitively, psychosocially, and educationally. One widespread nursing service which provides support for new mothers in Victoria is the Maternal and Child Health Service; however, teenage mothers appear reluctant to use such services. Why this should be so became an important question for this research, since little is known about the parenting practices of teenage mothers. This study therefore sought to explore mothering from the perspective of five sole supporting teenage mothers each of whom had a child over six months of age. The research methodology took an interpretive ethnographic approach and was guided by feminist principles. The data were collected through repeated interviewing, participant observation, informal discussions with key informants, field notes and journalling. Data analysis was aided by the use of the software, program NUD-IST. It was found that the young women in this study each chose to give birth with full realisation that their existence was dependent on the Welfare State. Unanticipated, however, were the many structural barriers which made their lives cataclysmic, but these reinforced their determination to prove themselves worthy and capable mothers. The young women negotiated motherhood through a range of social supports and through maternal practice. Unquestionably, their social dependency on the welfare system forced them into marginal citizen status. Moreover, absolute and intrinsic poverty levels were experienced, brought about by inadequate welfare payments. Formal support agencies, such as the Maternal and Child Health nurses were rarely approached to provide childrearing support beyond the initial months following birthing, since the teenagers' basic needs such as shelter, food and clothing took precedence over their parenting needs. Additionally, some nurses were perceived to hold judgmental attitudes towards teenage mothers. It was far easier to forestall confrontation with nurses and the other 'older' women clientele by avoiding them. Thus XI they turned to charitable agencies who provided a safety net in the form of emergency supplies of money, food, or equipment. Informal networks of friends provided alternative modes of support when family help failed to materialise. The children, however, provided the young women with an opportunity to transform their lives by breaking free of the past, and by creating a new, mature existence for themselves. Despite being abandoned by family, friends, lovers and society, in the privacy and isolation of their own homes, they attempted to provide a more nurturing environment for their children than they themselves had received. Each bestowed unconditional maternal love on the child and were rewarded through the pleasures of watching their children grow and develop into worthwhile individuals. The children became the focus of their attention and their reason for living. In the course of their welfare dependency, the young women became public property, targets of surveillance, and were subjected to stigmatising and condescending public attitudes wherever they went. In this way, it was evident that they were an oppressed group, but each found ways of resisting. Rather than focussing on their oppressive or disabling lives, or dwelling on their disadvantaged status, the young women sought their identities as mature women through motherhood and by demonstrating that they could do this important job well. Through motherhood their lives had meaning and a sense of purpose. The thesis concludes that motherhood in the teenage years is difficult. However, if appropriate supports are made available, teenage mothers need be no different from non-teenage mothers. But with state resources shrinking, and their own resources limited, teenage mothers are disadvantaged. In some ways, this study showed that all levels of support were inadequate, although those provided through the charitable organizations were seen to be the most appropriate. This reflects the current policy of economic rationalism adopted by most Western liberal democracies in the 1980s and 1990s and no less by the former Keating Labor Government in Australia.

Modeling data processing activity to assess the internal control function

This thesis describes research that was conducted into the potential of modeling the activities of the Data Processing Department as an aid to the computer auditor. A methodology is composed to aid in the evaluation of the Internal Controls, particularly the General Controls relative to computer processing. Consisting of three major components, the methodology enables the auditor to model the presumed activities of the Data Processing Department against the actual activities, as recorded on the Operating System Log. The first component of the methodology is the construction and loading of a model of the presumed activities of the Data Processing Department from its verbal, scheduled, and reported activities. The second component is the generation of a description of the actual activities of the Data Processing Department from the information recorded on the Operating System Log. This is effected by reducing the Operating System Log to the format described by the Standard Audit File concept. Finally, the third component in the methodology is the modeling process itself. This is in fact a new analysis technique proposed for use by the EDP auditor. The modeling process is composed of software that compares the model developed and loaded in the first component, with the description of actual activity as collated by the second component. Results from this comparison are then reviewed by the auditor, who determines if they adequately depict the situation, or whether the models description as specified in the first component requires to be altered, and the modeling process re-initiated. In conducting the research, information and data from a production installation was used. Use of the ‘real-world’ input proved both the feasibility of developing a model of the reported activities of the Data Processing Department, and the adequacy of the operating system log as a source of information to report the departments actual activities. Additionally, it enabled the involvement and comment of practicing auditors. The research involved analysis of the effect of EDP on the audit process, structure of the EDP audit process, data reduction, data structures, model formalization, and model processing software. Additionally, the Standard Audit File concept was verified through its use by practising auditors, and expanded by the development of an indexed data structure, which enabled its analysis to be conducted interactively. Results from the trial implementation of the research software and methodology at a production installation confirmed the research hypothesis that the activities of the Data Processing Department could be modelled, and that there are substantial benefits from the EDP auditor in analysing this process. The research in fact provides a new source of information, and develops a new analysis technique for the EDP auditor. It demonstrates the utilization of computer technology to monitor itself for the audit function, and reasserts auditor independence by providing access to technical detail describing the processing activities of the computer.

The impact of ownership structure on corporate debt policy : two stage least square simultaneous model approach for post crisis period : evidence from Kuala Lumpur Stock Exchange

Ownership concentration as a governance mechanism has received considerable attention among academician, practitioners as well as policy makers because large-block shareholders are increasingly active in their demands that corporations adopt effective governance mechanisms to control managerial decisions, which include corporate debt policy. Earlier study on the agency model of the firm widely recognizes that the managerial ownership and external debt play an important role in mitigating agency conflicts and enhancing firm value. They also found that increase in the external monitors, for example the institutional investors, can actually play a useful role in limiting agency problems in the firm. This paper, using 100 Composite Index companies from Brusa Malaysia between 1998 to 2002 explores the impact of institutional holdings on managerial ownership and debt policy in an integrated framework by using a simultaneous equations estimation procedure (2SLS). The findings show that there is a significant impact of institutional ownership which serves effective control mechanism on managerial ownership and corporate debt policy as hypothesized. Findings of such evidence suggest that institutional holding thus have played an important role in managers' strategic management decision and reduce agency conflict. In addition, corporate debt policy too is governed by managerial ownership and exhibited a negative relation.

Enhancing hotel managers’ organisational commitment : an investigation of the impact of structure, needfor achievement and participative budgeting

This study investigates the role of decentralised structure and managers’ need for achievement as antecedents of participative budgeting, and the impact of the concurrent relationships of all three preceding variables on organisational commitment. Ninety-one managers from the Australian hotel industry participated in the study and data were analysed using path analysis. Direct and positive relationships were found between the two antecedent variables: decentralised structure and managers’ need for achievement, and participative budgeting. Participative budgeting, in turn, was found to have a direct and positive relationship with organisational commitment. The results of the study have implications for the design of effective management control processes and for human resource management of hospitality organisations.

The relation between decentralised structure, budgetary participation and organisational commitment : the moderating role of managers' value orientation towards innovation

Reports the results of a study which investigated the moderating role of managers’ value orientation towards innovation (VOI) on the relationships between managers’ organisational commitment and two management control features – decentralised organisational structure and budgetary participation. Data for the study were collected from 116 managers in manufacturing firms. The results indicate that managers’ VOI has a significant moderating effect on the relationships between the two management control features and managers’ organisational commitment. The results reveal that the relationships are stronger for managers with high VOI than for managers with low VOI. These results have implications for enhancing managers’ organisational commitment through the design of management control systems appropriate for the extent of innovative work values promoted by organisations.

Selection of working correlation structure and best model in GEE analyses of longitudinal data

The Generalized Estimating Equations (GEE) method is one of the most commonly used statistical methods for the analysis of longitudinal data in epidemiological studies. A working correlation structure for the repeated measures of the outcome variable of a subject needs to be specified by this method. However, statistical criteria for selecting the best correlation structure and the best subset of explanatory variables in GEE are only available recently because the GEE method is developed on the basis of quasi-likelihood theory. Maximum likelihood based model selection methods, such as the widely used Akaike Information Criterion (AIC), are not applicable to GEE directly. Pan (2001) proposed a selection method called QIC which can be used to select the best correlation structure and the best subset of explanatory variables. Based on the QIC method, we developed a computing program to calculate the QIC value for a range of different distributions, link functions and correlation structures. This program was written in Stata software. In this article, we introduce this program and demonstrate how to use it to select the most parsimonious model in GEE analyses of longitudinal data through several representative examples.

Knowledge sharing in professional accountancy firms : the effects of task complexity and management control system

Numerous empirical studies on knowledge management have focused on effectiveness of enablers such as organizational structure (Bennett and Gabriel, 1999; Gold et al., 2001), technology (Gold et al., 2001; O’Dell and Grayson, 1998), culture (DeLong and Fahey, 2000; Gupta and Govindarajan, 2000), managerial system (Nonaka, 1994; Sveiby, 1997) and strategy (Bierly and Chakrabarti, 1996; Holsapple and Joshi, 2001) on knowledge sharing. These enablers are organizational infrastructure or mechanism for facilitating the sharing of knowledge in a firm. In knowledge-intensive firms, task complexity and management control systems (MCS) can potentially affect the mode and effectiveness of knowledge sharing. However, these two factors have not been distinctly and explicitly investigated and discussed in literature relevant to the domain of knowledge sharing and management. This study proposes to examine how task complexity and the design of MCS could be the key determinants of the mode and effectiveness of knowledge sharing in professional accounting firms or practices.

Management control systems and effectiveness of knowledge sharing

Numerous empirical studies on knowledge management have examined the relative effectiveness of various enablers, such as organizational structure (Bennett and Gabriel, 1999; Gold et aI., 2001), technology (Gold et aI., 2001; O'Dell and Grayson, 1998), culture (DeLong and Fahey, 2000; Gupta and Govindarajan, 2000), managerial system (Nonaka, 1994; Sveiby, 1997) and strategy (Bierly and Chakrabarti, 1996; Holsapple and Joshi, 2001) on knowledge creation and sharing in organizations. Little research has focused on the role of management control systems (MCS) in facilitating knowledge sharing in knowledge-intensive firms (Ditillo, 2004). This study examines how the interactive use of management control systems (MCS) could facilitate the different modes of knowledge sharing among accounting professionals in Malaysia. Based on Nonaka's (1994) knowledge sharing mode, this study found a highly significant relationship between an interactive use of MCS and knowledge sharing to suggest that a more open, less fmancial-oriented and more interactive type of MCS tends to interlink and underpin organizational social process which is the central part of the knowledge sharing process. While professional accountants are generally keen to gain access to knowledge databases to source for possible task solutions, they are generally hesitant to share their tacit knowledge by transforming that knowledge into explicit form. The fmding suggests that there may be cultural-related factors that inhibit sharing of one's tacit knowledge totally and completely.