Estradiol enables cortisol to act directly upon the pituitary to suppress pituitary responsiveness to GnRH in sheep

We have shown that cortisol infusion reduced the luteinizing hormone (LH) response to fixed hourly GnRH injections in ovariectomized ewes treated with estradiol during the non-breeding season (pituitary-clamp model). In contrast, cortisol did not affect the response to 2 hourly invariant GnRH injections in hypothalamo-pituitary disconnected ovariectomized ewes during the breeding season. To understand the differing results in these animal models and to determine if cortisol can act directly at the pituitary to suppress responsiveness to GnRH, we investigated the importance of the frequency of GnRH stimulus, the presence of estradiol and stage of the circannual breeding season. In experiment 1, during the non-breeding season, ovariectomized ewes were treated with estradiol, and pulsatile LH secretion was restored with i.v. GnRH injections either hourly or 2 hourly in the presence or absence of exogenous cortisol. Experiments 2 and 3 were conducted in hypothalamo-pituitary disconnected ovariectomized ewes in which GnRH was injected i.v. every 2 h. Experiment 2 was conducted during the non-breeding season and saline or cortisol was infused for 30 h in a cross-over design. Experiment 3 was conducted during the non-breeding and breeding seasons and saline or cortisol was infused for 30 h in the absence and presence of estradiol using a cross-over design. Samples were taken from all animals to measure plasma LH. LH pulse amplitude was reduced by cortisol in the pituitary clamp model with no difference between the hourly and 2-hourly GnRH pulse mode. In the absence of estradiol, there was no effect of cortisol on LH pulse amplitude in GnRH-replaced ovariectomized hypothalamo-pituitary disconnected ewes in either season. The LH pulse amplitude was reduced in both seasons in experiment 3 when cortisol was infused during estradiol treatment. We conclude that the ability of cortisol to reduce LH secretion does not depend upon the frequency of GnRH stimulus and that estradiol enables cortisol to act directly on the pituitary of ovariectomized hypothalamo-pituitary disconnected ewes to suppress the responsiveness to GnRH; this effect occurs in the breeding and non-breeding seasons.

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"Minerals", "petroleum" and "operations" in the Mineral and Petroleum Resources Development Act 28 of 2002 : a geologist as devil's advocate for a change? "

This article examines the meaning of "minerals", petroleum, "operations" and activities in relation to such substances to determine the ambit of the application of the Minerals and Petroleum Resources Development Act 28 of 2002, the type of rights necessary for such operations and activities and the ambit of these rights. The examination of the meaning of these concepts takes place with reference to prior definitions in statutes and also from a natural science and geology perspective. An attempt is made to show that the legal definitions do no always correspond with the geological meanings and the meanings on the ground. It is questioned whether in recent legislation why more reliance is not placed on input from geologists in the field.

Artikel 3(1) en (2) van die Mineral and Petroleum Resources Development Act 28 van 2002: 'n herbeskouing

Sections 3(1) and 3(2) of the Mineral and Petroleum Resources Development Act 28 of 2002
This contribution entails a discussion of the impact of section 3 of the Mineral and Petroleum Resources Development Act on various aspects of the new mineral and petroleum law. At the core of the discussion is the question of how this section is interpreted by various commentators, and the implications of the different opinions on the application of the section. The initial discussion highlights problems with the new definition of a "mineral": Soil, including topsoil is at present included in die definition of a "mineral" in the act. The definition should be rectified by the legislature as it has far-reaching consequences in respect of the extent of the state's power in terms of section 3(2) of the act to grant entitlements in respect of minerals, including topsoil. The implications of section 3 for the control and management of minerals are discussed and placed in the context of the question about the constitutionality of the act. It is argued that legislative guidance is urgently needed to clarify continuing uncertainty, caused by sloppy drafting and different opinions about the connection between private law and public law in relation to minerals and the actual position of existing right holders.

Extending the Workers' Compensation Act 1987 (N.S.W.) to include independent contractors and to allow more highly paid workers to insure fully their income, with particular reference to engineers

In mid-1987, the existing workers’ compensation system in New South Wales was replaced by a new Scheme, called ‘WorkCover’. While WorkCover solved a number of the financial problems that had plagued its predecessor, its enactment created other issues. Furthermore, WorkCover has failed to deal with a number of gaps in providing compensation for occupational injuries, most notably those suffered by independent contractors. By combining a study of aspects of industrial law and industrial relations, this thesis will examine some of those problems and gaps, in particular: (a) Should WorkCover be amended to enable independent contractors to come within its ambit? (b) Should there be additional insurance cover available (known as ‘top-up’ insurance) to insure those parts of workers’ wages presently left unprotected by WorkCover? (c) Should workers be permitted to take out another form of ‘top-up’ insurance to increase the quantum of death cover presently provided by the Scheme? (d) Should independent contractors who arc permitted to enter WorkCover also be permitted to obtain the extended cover set out in (b) and (c) above? Where appropriate, the thesis compares WorkCover to the workers’ compensation schemes in other Australian jurisdictions. It develops each of the matters referred to above by referring to the results of the writer’s survey of members of the Institution of Engineers (NSW Branch) which was conducted in May and June 1991.

Assessing behaviour support plans for people with intellectual disability before and after the Victorian Disability Act 2006

Background : This study sought to elucidate the extent to which behaviour support plans for people with intellectual disability are inclusive of best practice criteria, with a comparison made prior to and following proclamation of the Disability Act (2006) in Victoria, Australia.

Method : This study used a data collection instrument developed by the researchers incorporating best practice criteria as identified in the review of literature and Victorian legislative requirements. The instrument was used to assess a sample of behaviour support plans.

Results : Best practice criteria are inadequately included in behaviour support plans with little difference between pre- and post-Act plans.

Conclusion : The results of this study indicate that disability support staff are ill equipped to undertake the complex assessments, planning, and implementation associated with behaviour support strategies, despite the legislative framework that guides and directs this intervention

Supervision among mental health workers in the ACT

There is a common perception among mental health professionals of the purpose of clinical supervision. However, only two-thirds of professionals in the ACT currently receive regular supervision with comparisons between nurses and allied health workers showing few differences in experience, training, access and barriers to supervision, both supervisees and supervisors.