Acute cadmium chloride administration induces hepatic and renal cytochrome P450 2A5 in the mouse

Modulation of the cytochrome P450 (CYP) monooxygenase system by cadmium was investigated in male, adult DBA/2J mice treated with a single dose (16 Amol/kg body weight, i.p.) of cadmium chloride (CdCl2) at various time points. The total CYP content of kidney microsomes started to decrease 4 hours earlier than in the liver (P < 0.05), with maximal decreases at 24 hours of 56% and 85% in the liver and kidney, respectively. In contrast, both hepatic and renal coumarin 7-hydroxylase (COH) activity (indicative of CYP2A5 activity) relative to total CYP content started to progressively increase at 8 hours, with renal activity 61 times higher than the hepatic activity. Maximum increases were observed, 15-fold in the liver and 64-fold in the kidney after 24 hours. Liver and kidney CYP2A5 mRNA levels increased maximally 12 and 4 hours after treatment, respectively and decreased to almost half 6 hours later. In contrast, kidney and liver CYP2A5 protein levels increased maximally at 18 and 24 hours. This study demonstrates that hepatic and renal CYP2A5 is upregulated by cadmium with a faster response in the kidney than in the liver. This observation is concordant with the fact that kidney is the target organ for cadmium toxicity. The observed increase in the mRNA but not in protein levels after maximal induction suggests involvement of post-transcriptional mechanisms in the regulation of CYP2A5 expression by cadmium.

Green turtle somatic growth dynamics in a spatially disjunct Great Barrier Reef metapopulation

The growth dynamics of green sea turtles resident in four separate foraging grounds of the southern Great Barrier Reef genetic stock were assessed using a nonparametric regression modeling approach. Juveniles recruit to these grounds at the same size, but grow at foraging-ground-dependent rates that result in significant differences in expected size- or age-at-maturity. Mean age-at-maturity was estimated to vary from 25-50 years depending on the ground. This stock comprises mainly the same mtDNA haplotype, so geographic variability might be due to local environmental conditions rather than genetic factors, although the variability was not a function of latitudinal variation in environmental conditions or whether the food stock was seagrass or algae. Temporal variability in growth rates was evident in response to local environmental stochasticity, so geographic variability might be due to local food stock dynamics. Despite such variability, the expected size-specific growth rate function at all grounds displayed a similar nonmonotonic growth pattern with a juvenile growth spurt at 60-70 cm curved carapace length, (CCL) or 15-20 years of age. Sex-specific growth differences were also evident with females tending to grow faster than similar-sized males after the Juvenile growth spurt. It is clear that slow sex-specific growth displaying both spatial and temporal variability and a juvenile growth spurt are distinct growth behaviors of green turtles from this stock.

Thirty-year recovery trend in the once depleted Hawaiian green sea turtle stock

The green sea turtle is one of the long-lived species that comprise the charismatic marine megafauna. The green turtle has a long history of human exploitation with some stocks extinct. Here we report on a 30-year study of the nesting abundance of the green turtle stock endemic to the Hawaiian Archipelago. We show that there has been a substantial long-term increase in abundance of this once seriously depleted stock following cessation of harvesting since the 1970s. This population increase has occurred in a far shorter period of time than previously thought possible. There was also a distinct 3-4 year periodicity in annual nesting abundance that might be a function of regional environmental stochasticity that synchronises breeding behaviour throughout the Archipelago. This is one of the few reliable long-term population abundance time series for a large long-lived marine species, which are needed for gaining insights into the recovery process of long-lived marine species and long-term ecological processes. (C) 2003 Elsevier Ltd. All rights reserved.

An Analytical Solution for the Elastic Lateral-Distortional Buckling of I-section Beams

Lateral-distortional buckling may occur in I-section beams with slender webs and stocky flanges. A computationally efficient method is presented in this paper to study this phenomenon. Previous studies on distortional buckling have been on the use of 3(rd) and 5(th) order polynomials to model the displacements. The present study provides an alternative way, using Fourier Series, to model the behaviour. Beams of different cross-sectional dimensions, load cases and restraint conditions are examined and compared. The accuracy and versatility of the method are verified by calibrating against the results of other published studies. The present method is believed to be a simple and efficient way of determining the buckling load and mode shapes of I-section beams that are susceptible to lateral-distortional buckling modes.

Distortional buckling of I-beams by finite element method

Distortional buckling, unlike the usual lateral-torsional buckling in which the cross-section remains rigid in its own plane, involves distortion of web in the cross-section. This type of buckling typically occurs in beams with slender web and stocky flanges. Most of the published studies assume the web to deform with a cubic shape function. As this assumption may limit the accuracy of the results, a fifth order polynomial is chosen here for the web displacements. The general line-type finite element model used here has two nodes and a maximum of twelve degrees of freedom per node. The model not only can predict the correct coupled mode but also is capable of handling the local buckling of the web.

Measuring and incorporating vulnerability into conservation planning

Conservation planning is the process of locating and designing conservation areas to promote the persistence of biodiversity in situ. To do this, conservation areas must be able to mitigate at least some of the proximate threats to biodiversity. Information on threatening processes and the relative vulnerability of areas and natural features to these processes is therefore crucial for effective conservation planning. However, measuring and incorporating vulnerability into conservation planning have been problematic. We develop a conceptual framework of the role of vulnerability assessments in conservation planning and propose a definition of vulnerability that incorporates three dimensions: exposure, intensity, and impact. We review and categorize methods for assessing the vulnerability of areas and the features they contain and identify the relative strengths and weaknesses of each broad approach, Our review highlights the need for further development and evaluation of approaches to assess vulnerability and for comparisons of their relative effectiveness.

Evaluating boards and directors

The challenge for boards is to prevent crises in the organisations they govern. Performance evaluation is a key means by which boards can recognise and correct corporate governance problems and add real value to their organisations. Our paper provides a practical introduction to board and director evaluations. We discuss the reasons for governance failures and how board evaluations can help prevent them from occurring. We then review the performance pressures facing boards and the benefits of board evaluations in meeting these pressures. Finally, we introduce our framework for a successful board and/or individual director evaluation, whatever the company type. In this framework, we suggest there are seven key questions to consider when planning a board evaluation and discuss each of these seven decision areas.

Beef production and the environment: Is it really 'hard to be green when you are in the red'?

The statement. 'it is hard to be green when you are in the red' is commonly used by pnmary producers to explain the necessity of placing a greater emphasis on financial survival rather than longer term environmental sustainability. The subject of environmental sustainabilty on pastoral properties was explored during face-to:face interviews with cattle graziers in the Filzroy Basin area of Central Queensland. Findings from the study suggest that while economic factors are important, they are not the only determinant in whether a landholder prioritises environmental sustainability, Rather. social factors such as knowledge claims. beliefs, attitudes. values, peer pressure and social sanctioning, constructed and enacted within the productivist paradigm of primary production. play a crucial role in how landholders manage their natural assets. This suggests that the edict that 'It is hard to be green when you are in the red' is inaccurate and does not explain why conservation-focused pastoral management is not yet occurring on a large scale

Multiple directorships and corporate performance in Australian listed companies

How many directorships are too many? Globally, normative advice emphasises the importance of limiting the number of directorships any individual should hold due to the workloads they entail. However, there is little empirical evidence to support this view. Rather, there is a strong tradition of supporting multiple directorships as a mechanism for the firm to co-opt external resources. To explore the issue of director workloads and multiple directorships, we first consider the issues related to multiple directorships and outline the conclusions of extant international and Australian studies into multiple directorships. We then detail our objectives in undertaking this research and our approach to data collection. Our findings indicate that the incidence of multiple directorships in Australian listed companies is low. We also find that many of the apparent examples of multiple directorships are due to related entities, which share common directors and, due to the nature of these entities, have much lower workload requirements. Further, there does not appear to be any relationship between holding multiple directorships and firm financial performance. Finally, we discuss the implications for boards and those interested in governance, particularly the need to ensure governance recommendations and guidelines reflect empirical findings. We offer one solution to address the concerns of boards, investors, other stakeholders and the community regarding multiple directorships: board and individual director evaluations.

Adsorption of Lennard-Jones fluids in carbon slit pores of a finite length. A computer simulation study

The adsorption of simple Lennard-Jones fluids in a carbon slit pore of finite length was studied with Canonical Ensemble (NVT) and Gibbs Ensemble Monte Carlo Simulations (GEMC). The Canonical Ensemble was a collection of cubic simulation boxes in which a finite pore resides, while the Gibbs Ensemble was that of the pore space of the finite pore. Argon was used as a model for Lennard-Jones fluids, while the adsorbent was modelled as a finite carbon slit pore whose two walls were composed of three graphene layers with carbon atoms arranged in a hexagonal pattern. The Lennard-Jones (LJ) 12-6 potential model was used to compute the interaction energy between two fluid particles, and also between a fluid particle and a carbon atom. Argon adsorption isotherms were obtained at 87.3 K for pore widths of 1.0, 1.5 and 2.0 nm using both Canonical and Gibbs Ensembles. These results were compared with isotherms obtained with corresponding infinite pores using Grand Canonical Ensembles. The effects of the number of cycles necessary to reach equilibrium, the initial allocation of particles, the displacement step and the simulation box size were particularly investigated in the Monte Carlo simulation with Canonical Ensembles. Of these parameters, the displacement step had the most significant effect on the performance of the Monte Carlo simulation. The simulation box size was also important, especially at low pressures at which the size must be sufficiently large to have a statistically acceptable number of particles in the bulk phase. Finally, it was found that the Canonical Ensemble and the Gibbs Ensemble both yielded the same isotherm (within statistical error); however, the computation time for GEMC was shorter than that for canonical ensemble simulation. However, the latter method described the proper interface between the reservoir and the adsorbed phase (and hence the meniscus).

Synthesis, crystal structure and herbicidal activity of mimics of intermediates of the KARI reaction

Two mimics of the intermediate in the reaction catalyzed by ketol-acid reductoisomerase (KARI) were synthesized. Their structures were established on the basis of elemental analyses, IR, H-1 NMR and GC/mass detector. The crystal structure of compound 2 was found to be a substituted dioxane, formed by the condensation of two molecules. The two compounds showed some herbicidal activity on the basis of tests using rape root and barnyard grass growth inhibition. However, the herbicidal effect was weaker in greenhouse tests. (c) 2004 Society of Chemical Industry.

How useful is the genuine savings rate as a sustainability indicator for regions within countries? Australia and Queensland compared

This article shows how macroeconomic indicators of sustainable development can be applied to the Queensland economy. While recognising the complex and contentious theoretical and practical issues in deriving the Genuine Savings Rate (GSR) to serve as such an indicator, we use the World Bank's methodology, which includes only mineral depletion, deforestation and carbon dioxide emissions as environmental terms, to estimate GSRs for Queensland for the period 1989 to 1999, and compare these to World Bank estimates of Australia's GSR for the same period. We find that Queensland has a higher rate of natural resource depletion and a lower GSR than the whole of Australia. We also examine how well the World Bank GSR performs as a 'headline' measure of overall sustainability, review criticisms of the GSR, and compare its implicit policy implications with those of net state savings, and of the GSR plus a suite of other indicators.

Momentum transfer effects in the transport of adsorbate at a nano-patterned surface

Adsorbate molecules scattered in the repulsive field of a surface feature in the form of a semi-cylindrical stripe may be considered as a simple model for a nano-patterned surface. The extent of scattering was conveniently expressed as the tangential momentum accommodation coefficient. An analytical result was obtained using a simple local specular reflection hypothesis in contrast to the more complicated situation of an array of atoms discussed elsewhere, in which screening and secondary reflection may occur (Nicholson and Bhatia 2005). It was also demonstrated that a simple 2D representation leads to the same result for the tangential momentum accommodation coefficient.

Adsorption in slit pores and pore-size distribution: A molecular layer structure theory

A new approach is developed to analyze the thermodynamic properties of a sub-critical fluid adsorbed in a slit pore of activated carbon. The approach is based on a representation that an adsorbed fluid forms an ordered structure close to a smoothed solid surface. This ordered structure is modelled as a collection of parallel molecular layers. Such a structure allows us to express the Helmholtz free energy of a molecular layer as the sum of the intrinsic Helmholtz free energy specific to that layer and the potential energy of interaction of that layer with all other layers and the solid surface. The intrinsic Helmholtz free energy of a molecular layer is a function (at given temperature) of its two-dimensional density and it can be readily obtained from bulk-phase properties, while the interlayer potential energy interaction is determined by using the 10-4 Lennard-Jones potential. The positions of all layers close to the graphite surface or in a slit pore are considered to correspond to the minimum of the potential energy of the system. This model has led to accurate predictions of nitrogen and argon adsorption on carbon black at their normal boiling points. In the case of adsorption in slit pores, local isotherms are determined from the minimization of the grand potential. The model provides a reasonable description of the 0-1 monolayer transition, phase transition and packing effect. The adsorption of nitrogen at 77.35 K and argon at 87.29 K on activated carbons is analyzed to illustrate the potential of this theory, and the derived pore-size distribution is compared favourably with that obtained by the Density Functional Theory (DFT). The model is less time-consuming than methods such as the DFT and Monte-Carlo simulation, and most importantly it can be readily extended to the adsorption of mixtures and capillary condensation phenomena.