Refinements in stress echocardiographic techniques improve inter-institutional agreement in interpretation of dobutamine stress echocardiograms

Aims To determine the degree of inter-institutional agreement in the assessment of dobutamine stress echocardiograms using modern stress echo cardiographic technology in combination with standardized data acquisition and assessment criteria. Method and Results Among six experienced institutions, 150 dobutamine stress echocardiograms (dobutamine up to 40 mug.kg(-1) min(-1) and atropine up to I mg) were performed on patients with suspected coronary artery disease using fundamental and harmonic imaging following a consistent digital acquisition protocol. Each dobutamine stress echocardiogram was assessed at every institution regarding endocardial visibility and left ventricular wall motion without knowledge of any other data using standardized reading criteria. No patients were excluded due to poor image quality or inadequate stress level. Coronary angiography was performed within 4 weeks. Coronary angiography demonstrated significant coronary artery disease (less than or equal to50% diameter stenosis) in 87 patients. Using harmonic imaging an average of 5.2+/-0.9 institutions agreed on dobutamine stress echocardiogram results as being normal or abnormal (mean kappa 0.55; 95% CI 0.50-0.60). Agreement was higher in patients with no (equal assessment of dobutamine stress echocardiogram results by 5.5 +/- 0.8 institutions) or three-vessel coronary artery disease (5.4 +/- 0.8 institutions) and lower in one- or two- vessel disease (5.0 +/- 0.9 and 5.2 +/- 1.0 institutions, respectively-, P=0.041). Disagreement on test results was greater in only minor wall motion abnormalities. Agreement on dobutamine stress echocardiogram results was lower using fundamental imaging (mean kappa 0.49; 95% CI 0.44-0.54; P

In the vernacular: On the architecture of the National Museum of Australia

This Article does not have an abstract.

Color constancy and the functional significance of McCollough effects

A central problem in visual perception concerns how humans perceive stable and uniform object colors despite variable lighting conditions (i.e. color constancy). One solution is to 'discount' variations in lighting across object surfaces by encoding color contrasts, and utilize this information to 'fill in' properties of the entire object surface. Implicit in this solution is the caveat that the color contrasts defining object boundaries must be distinguished from the spurious color fringes that occur naturally along luminance-defined edges in the retinal image (i.e. optical chromatic aberration). In the present paper, we propose that the neural machinery underlying color constancy is complemented by an 'error-correction' procedure which compensates for chromatic aberration, and suggest that error-correction may be linked functionally to the experimentally induced illusory colored aftereffects known as McCollough effects (MEs). To test these proposals, we develop a neural network model which incorporates many of the receptive-field (RF) profiles of neurons in primate color vision. The model is composed of two parallel processing streams which encode complementary sets of stimulus features: one stream encodes color contrasts to facilitate filling-in and color constancy; the other stream selectively encodes (spurious) color fringes at luminance boundaries, and learns to inhibit the filling-in of these colors within the first stream. Computer simulations of the model illustrate how complementary color-spatial interactions between error-correction and filling-in operations (a) facilitate color constancy, (b) reveal functional links between color constancy and the ME, and (c) reconcile previously reported anomalies in the local (edge) and global (spreading) properties of the ME. We discuss the broader implications of these findings by considering the complementary functional roles performed by RFs mediating color-spatial interactions in the primate visual system. (C) 2002 Elsevier Science Ltd. All rights reserved.

Parenthood and pay in Australia and the UK: evidence from workplace surveys

This article addresses the effect of parenthood on pay, examining potential reasons for-differences between Australia and the UK that are evident in spite of their similarly minimalist. male, breadwinner style approaches to work/family issues, Although cross-national differences reflect complex intersections of policy combinations, institutional frameworks, patterns of employment and gender contracts that cannot be assessed in a single analysis, the data used in this analysis uncover some of the factors that contribute to different outcomes. Motherhood penalties in the UK appear to be associated primarily with the comparatively low level of part-time earnings in that country, while higher premiums to fatherhood at least in part reflect a wider overall wage distribution. These findings reinforce the heed to interpret earnings effects of parenthood within the context of national patterns of employment and wage distribution; and highlight the breadth of strategies needed to deliver more equitable outcomes.

Evaluating Australia's National Medicines Policy using geographical mapping

Background: There has been a proliferation of quality use of medicines activities in Australia since the 1990s. However, knowledge of the nature and extent of these activities was lacking. A mechanism was required to map the activities to enable their coordination. Aims: To develop a geographical mapping facility as an evaluative tool to assist the planning and implementation of Australia's policy on the quality use of medicines. Methods: A web-based database incorporating geographical mapping software was developed. Quality use of medicines projects implemented across the country was identified from project listings funded by the Quality Use of Medicines Evaluation Program, the National Health and Medical Research Council, Mental Health Strategy, Rural Health Support, Education and Training Program, the Healthy Seniors Initiative, the General Practice Evaluation Program and the Drug Utilisation Evaluation Network. In addition, projects were identified through direct mail to persons working in the field. Results: The Quality Use of Medicines Mapping Project (QUMMP) was developed, providing a Web-based database that can be continuously updated. This database showed the distribution of quality use of medicines activities by: (i) geographical region, (ii) project type, (iii) target group, (iv) stakeholder involvement, (v) funding body and (vi) evaluation method. At September 2001, the database included 901 projects. Sixty-two per cent of projects had been conducted in Australian capital cities, where approximately 63% of the population reside. Distribution of projects varied between States. In Western Australia and Queensland, 36 and 73 projects had been conducted, respectively, representing approximately two projects per 100 000 people. By comparison, in South Australia and Tasmania approximately seven projects per 100 000 people were recorded, with six per 100 000 people in Victoria and three per 100 000 people in New South Wales. Rural and remote areas of the country had more limited project activity. Conclusions: The mapping of projects by geographical location enabled easy identification of high and low activity areas. Analysis of the types of projects undertaken in each region enabled identification of target groups that had not been involved or services that had not yet been developed. This served as a powerful tool for policy planning and implementation and will be used to support the continued implementation of Australia's policy on the quality use of medicines.

Close packed transitions in slit-shaped pores: Density functional theory study of methane adsorption capacity in carbon

An important feature of improving lattice gas models and classical isotherms is the incorporation of a pore size dependent capacity, which has hitherto been overlooked. In this paper, we develop a model for predicting the temperature dependent variation in capacity with pore size. The model is based on the analysis of a lattice gas model using a density functional theory approach at the close packed limit. Fluid-fluid and solid-fluid interactions are modeled by the Lennard-Jones 12-6 potential and Steele's 10-4-3, potential respectively. The capacity of methane in a slit-shaped carbon pore is calculated from the characteristic parameters of the unit cell, which are extracted by minimizing the grand potential of the unit cell. The capacities predicted by the proposed model are in good agreement with those obtained from grand canonical Monte Carlo simulation, for pores that can accommodate up to three adsorbed layers. Single particle and pair distributions exhibit characteristic features that correspond to the sequence of buckling and rhombic transitions that occur as the slit pore width is increased. The model provides a useful tool to model continuous variation in the microstructure of an adsorbed phase, namely buckling and rhombic transitions, with increasing pore width. (C) 2002 American Institute of Physics.

Density functional theory analysis of the influence of pore wall heterogeneity on adsorption in carbons

Density functional theory for adsorption in carbons is adapted here to incorporate a random distribution of pore wall thickness in the solid, and it is shown that the mean pore wall thickness is intimately related to the pore size distribution characteristics. For typical carbons the pore walls are estimated to comprise only about two graphene layers, and application of the modified density functional theory approach shows that the commonly used assumption of infinitely thick walls can severely affect the results for adsorption in small pores under both supercritical and subcritical conditions. Under supercritical conditions the Henry's law coefficient is overpredicted by as much as a factor of 2, while under subcritical conditions pore wall heterogeneity appears to modify transitions in small pores into a sequence of smaller ones corresponding to pores with different wall thicknesses. The results suggest the need to improve current pore size distrubution analysis methods to allow for pore wall heterogeneity. The density functional theory is further extended here to allow for interpore adsorbate interactions, and it appears that these interaction are negligible for small molecules such as nitrogen but significant for more strongly interacting heavier molecules such as butane, for which the traditional independent pore model may not be adequate.

Knowledge of the national emergency telephone number and prevalence and characteristics of those trained in CPR in Queensland: baseline information for targeted training interventions

Members of the community contribute to survival from out-of-hospital cardiac arrest by contacting emergency medical services and performing cardiopulmonary resuscitation (CPR) prior to the arrival of an ambulance. In Australia there is a paucity of information of the extent that community members know the emergency telephone number and are trained in CPR. A survey of Queensland adults (n = 4490) was conducted to ascertain current knowledge and training levels and to target CPR training. Although most respondents (88.3%) could state the Australian emergency telephone number correctly, significant age differences were apparent (P < 0.001). One in five respondents aged 60 years and older could not state the emergency number correctly. While just over half the respondents (53.9%) had completed some form of CPR training, only 12.1% had recent training. Older people were more likely to have never had CPR training than young adults. Additional demographic and socio-economic differences were found between those never trained in CPR and those who were. The results emphasise the need to increase CPR training in those aged 40 and over, particularly females, and to increase the awareness of the emergency telephone number amongst older people. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

A comparative study of carbon gasification with O-2 and CO2 by density functional theory calculations

A comparative study of carbon gasification with O-2 and CO2 was conducted by using density functional theory calculations. It was found that the activation energy and the number of active sites in carbon gasification reactions are significantly affected by both the capacity and manner of gas chemisorption. O-2 has a strong adsorption capacity and the dissociative chemisorption of O-2 is thermodynamically favorable on either bare carbon surface or even isolated edge sites. As a result, a large number of semiquinone and o-quinone oxygen can be formed indicating a significant increase in the number of active sites. Moreover, the weaker o-quinone C-C bonds can also drive the reaction forward at (ca. 30%) lower activation energy. Epoxy oxygen forms under relatively high O-2 pressure, and it can only increase the number of active sites, not further reduce the activation energy. CO2 has a lower adsorption capacity. Dissociative chemisorption of CO2 can only occur on two consecutive edge sites and o-quinone oxygen formed from CO2 chemisorption is negligible, let alone epoxy oxygen. Therefore, CO2-carbon reaction needs (ca 30%) higher activation energy. Furthermore, the effective active sites are also reduced by the manner Of CO2 chemisorption. A combination of the higher activation energy and the fewer active sites leads to the much lower reaction rate Of CO2-carbon.

Adsorption of aromatic compounds by activated carbon: Effects of functional groups and molecular size

The adsorption of three aromatic compounds on to an untreated carbon was investigated. The solution pH was lowered in all experiments so that all the solutes were in their molecular forms. It was shown that the difference in the maximum adsorption of the solutes was mainly a result of the difference in the sizes of the molecules and their functional groups. Further-more, it was illustrated that the packing arrangement was most likely edge-to-face (sorbate-sorbent) with various tilt angles. On the other hand, the affinity and heterogeneity of the adsorption systems were apparently related to the pK(a) values of the solutes.

The role of transaction costs and institutional forces in the outsourcing of recruitment

This study investigated reasons for the outsourcing of a core HRM function, recruitment. Drawing from transaction costs and institutional theories, it was hypothesised that the pressure to minimise transaction costs and the presence of industry trends towards outsourcing would be positively associated with the outsourcing of recruitment. Survey data were gathered from 1I 7 HR professionals in Australia. Both hypotheses were partially supported. Specifically, the outsourcing of recruitment activities was positively associated with trust in the agency supplying the recruitment service and with the need to reduce internal labour but not fixed costs. With regard to institutional theory, the outsourcing of recruitment was positively associated with mimetic but not coercive forces. The study concludes that although most assumptions about recruitment agency use are expressed in economic terms, in reality, HRM practices are also influenced by forces exerted by the institutional environment in which organisations are located.

The structural and functional diversity of naturally occurring antimicrobial peptides

Antimicrobial peptides occur in a diverse range of organisms from microorganisms to insects, plants and animals. Although they all have the common function of inhibiting or killing invading microorganisms they achieve this function using an extremely diverse range of structural motifs. Their sizes range from approximately 10-90 amino acids. Most carry an overall positive charge, reflecting a preferred mode of electrostatic interaction with negatively charged microbial membranes. This article describes the structural diversity of a representative set of antimicrobial peptides divided into five structural classes: those with agr-helical structure, those with bgr-sheet structure, those with mixed helical / bgr- sheet structure, those with irregular structure, and those incorporating a macrocyclic structure. There is a significant diversity in both the size and charge of molecules within each of these classes and between the classes. The common feature of their three-dimensional structures is, however, that they have a degree of amphipathic character in which there is separate localisation of hydrophobic regions and positively charged regions. An emerging trend amongst antimicrobial proteins is the discovery of more macrocyclic analogues. Cyclisation appears to impart an additional degree of stability on these molecules and minimizes proteolytic cleavage. In conclusion, there appear to be a number of promising opportunities for the development of novel clinically useful antimicrobial peptides based on knowledge of the structures of naturally occurring antimicrobial molecules.