Work domain analysis and sensors II: Pasteurizer II case study

In this paper we use sensor-annotated abstraction hierarchies (Reising & Sanderson, 1996, 2002a,b) to show that unless appropriately instrumented, configural displays designed according to the principles of ecological interface design (EID) might be vulnerable to misinterpretation when sensors become unreliable or are unavailable. Building on foundations established in Reising and Sanderson (2002a) we use a pasteurization process control example to show how sensor-annotated AHs help the analyst determine the impact of different instrumentation engineering policies on a configural display that is part of an ecological interface. Our analyses suggest that configural displays showing higher-order properties of a system are especially vulnerable under some conservative instrumentation configurations. However, sensor-annotated AHs can be used to indicate where corrective instrumentation might be placed. We argue that if EID is to be effectively employed in the design of displays for complex systems, then the information needs of the human operator need to be considered while instrumentation requirements are being formulated. Rasmussen's abstraction hierarchy-and particularly its extension to the analysis of information captured by sensors and derived from sensors-may therefore be a useful adjunct to up-stream instrumentation design. (C) 2002 Elsevier Science Ltd. All rights reserved.

Work domain analysis and sensors I: principles and simple example

In this paper we establish a foundation for understanding the instrumentation needs of complex dynamic systems if ecological interface design (EID)-based interfaces are to be robust in the face of instrumentation failures. EID-based interfaces often include configural displays which reveal the higher-order properties of complex systems. However, concerns have been expressed that such displays might be misleading when instrumentation is unreliable or unavailable. Rasmussen's abstraction hierarchy (AH) formalism can be extended to include representations of sensors near the functions or properties about which they provide information, resulting in what we call a sensor-annotated abstraction hierarchy. Sensor-annotated AHs help the analyst determine the impact of different instrumentation engineering policies on higher-order system information by showing how the data provided from individual sensors propagates within and across levels of abstraction in the AH. The use of sensor-annotated AHs with a configural display is illustrated with a simple water reservoir example. We argue that if EID is to be effectively employed in the design of interfaces for complex systems, then the information needs of the human operator need to be considered at the earliest stages of system development while instrumentation requirements are being formulated. In this way, Rasmussen's AH promotes a formative approach to instrumentation engineering. (C) 2002 Elsevier Science Ltd. All rights reserved.

Phenotypic and genotypic analysis of Helicoverpa armigera nucleopolyhedrovirus serially passaged in cell culture

Rapid accumulation of few polyhedra (FP) mutants was detected during serial passaging of Helicoverpa armigera nucleopolyhedrovirus (HaSNPV) in cell culture. 100% FP infected cells were observed by passage 6. The specific yield decreased from 178 polyhedra per cell at passage 2 to two polyhedra per cell at passage 6. The polyhedra at passage 6 were not biologically active, with a 28-fold reduction in potency compared to passage 3. Electron microscopy studies revealed that very few polyhedra were produced in an FP infected cell (< 10 polyhedra per section) and in most cases these polyhedra contained no virions. A specific failure in the intranuclear nucleocapsid envelopment process in the FP infected cells, leading to the accumulation of naked nucleocapsids, was observed. Genomic restriction endonuclease digestion profiles of budded virus DNA from all passages did not indicate any large DNA insertions or deletions that are often associated with such FP phenotypes for the extensively studied Autographa californica nucleopolyhedrovirus and Gaileria mellonella nucleopolyhedrovirus. Within an HaSNPV 25K FP gene homologue, a single base-pair insertion (an adenine residue) within a region of repetitive sequences (seven adenine residues) was identified in one plaque-purified HaSNPV FP mutant. Furthermore, the sequences obtained from individual clones of the 25KFP gene PCR products of a late passage revealed point mutations or single base-pair insertions occurring throughout the gene. The mechanism of FP mutation in HaSNPV is likely similar to that seen for Lymantria dispar nucleopolyhedrovirus, involving point mutations or small insertions/deletions of the 25K FP gene.

Analysis of the wind field and heat budget in an alpine lake basin during summertime fair weather conditions

Observational data collected in the Lake Tekapo hydro catchment of the Southern Alps in New Zealand are used to analyse the wind and temperature fields in the alpine lake basin during summertime fair weather conditions. Measurements from surface stations, pilot balloon and tethersonde soundings, Doppler sodar and an instrumented light aircraft provide evidence of multi-scale interacting wind systems, ranging from microscale slope winds to mesoscale coast-to-basin flows. Thermal forcing of the winds occurred due to differential heating as a consequence of orography and heterogeneous surface features, which is quantified by heat budget and pressure field analysis. The daytime vertical temperature structure was characterised by distinct layering. Features of particular interest are the formation of thermal internal boundary layers due to the lake-land discontinuity and the development of elevated mixed layers. The latter were generated by advective heating from the basin and valley sidewalls by slope winds and by a superimposed valley wind blowing from the basin over Lake Tekapo and up the tributary Godley Valley. Daytime heating in the basin and its tributary valleys caused the development of a strong horizontal temperature gradient between the basin atmosphere and that over the surrounding landscape, and hence the development of a mesoscale heat low over the basin. After noon, air from outside the basin started flowing over mountain saddles into the basin causing cooling in the lowest layers, whereas at ridge top height the horizontal air temperature gradient between inside and outside the basin continued to increase. In the early evening, a more massive intrusion of cold air caused rapid cooling and a transition to a rather uniform slightly stable stratification up to about 2000 m agl. The onset time of this rapid cooling varied about 1-2 h between observation sites and was probably triggered by the decay of up-slope winds inside the basin, which previously countered the intrusion of air over the surrounding ridges. The intrusion of air from outside the basin continued until about mid-night, when a northerly mountain wind from the Godley Valley became dominant. The results illustrate the extreme complexity that can be caused by the operation of thermal forcing processes at a wide range of spatial scales.

Are tryptophan and 5-hydroxytryptophan effective treatments for depression? A meta-analysis

Objective: To review the literature regarding the effectiveness of 5-hydroxytryptophan (5-HT) and L-tryptophan in the treatment of unipolar depression. Methods: A systematic review of the literature from 1966 to 2000 using the search terms 'tryptophan', 5-hydroxytryptophan', '5-HTP', '5-HT' and 'depression'. We extracted and grouped data for meta-analysis by pooling odds ratios (OR) and relative risks where possible. Results: One hundred and eight studies were located of which only two studies, one of 5-HT and one of L-tryptophan, with a total of 64 patients met sufficient quality criteria to be included. These studies suggest 5-HT and L-tryptophan are better than placebo at alleviating depression (Peto OR = 4.1, 95% CI = 1.3-13.2). However, the small size of the studies, and the large number of inadmissible, poorly executed studies, casts doubt on the result from potential publication bias, and suggests that they are insufficiently evaluated to assess their effectiveness. Conclusions: A large body of evidence was subjected to very basic criteria for assessing reliability and validity, and was found to largely be of insufficient quality to inform clinical practice. More well-designed studies are urgently required to enable an assessment of what may be an effective class of agents.

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.

Behavior of argon gas release from manganese oxide minerals as revealed by Ar-40/Ar-39 laser incremental heating analysis

Manganese oxides in association with paleo-weathering may provide significant insights into the multiple factors affecting the formation and evolution of weathering profiles, such as temperature, precipitation, and biodiversity. Laser probe step-heating analysis of supergene hollandite and cryptomelane samples collected from central Queensland, Australia, yield well-defined plateaus and consistent isochron ages, confirming the feasibility, dating very-fined supergene manganese oxides by Ar-40/(39) Ar technique. Two distinct structural sites hosting Ar isotopes can be identified in light of their degassing behaviors obtained by incremental heating analyses. The first site, releasing its gas fraction at the laser power 0.2-0.4 W, yields primarily Ar-40(atm), Ar-38(atm), and Ar-36(atm), (atmospheric Ar isotopes). The second sites yield predominantly Ar-40* (radiogenic Ar-40), Ar-39(K), and Ar-38(K) (nucleogenic components), at similar to0.5-1.0 W. There is no significant Ar gas released at the laser power higher than 1.0 W, indicating the breakdown of the tunnel sites hosting the radiogenic and nucleogenic components. The excellent match between the degassing behaviors of Ar-40*, Ar-39(K), and Ar-38(K) suggests that these isotopes occupy the same crystallographic sites and that Ar-39(K) loss from the tunnel site by recoil during neutron irradiation and/or bake-out procedure preceding isotopic analysis does not occur. Present investigation supports that neither the overwhelming atmospheric Ar-40 nor the very-fined nature of the supergene manganese oxides poses problems in extracting meaningful weathering geo-chronological information by analyzing supergene manganese oxides minerals.

Estimation of total body water from bioelectrical impedance analysis in patients with pancreatic cancer - agreement between three methods of prediction

Introduction Bioelectrical impedance analysis (BIA) is a useful field measure to estimate total body water (TBW). No prediction formulae have been developed or validated against a reference method in patients with pancreatic cancer. The aim of this study was to assess the agreement between three prediction equations for the estimation of TBW in cachectic patients with pancreatic cancer. Methods Resistance was measured at frequencies of 50 and 200 kHz in 18 outpatients (10 males and eight females, age 70.2 +/- 11.8 years) with pancreatic cancer from two tertiary Australian hospitals. Three published prediction formulae were used to calculate TBW - TBWs developed in surgical patients, TBWca-uw and TBWca-nw developed in underweight and normal weight patients with end-stage cancer. Results There was no significant difference in the TBW estimated by the three prediction equations - TBWs 32.9 +/- 8.3 L, TBWca-nw 36.3 +/- 7.4 L, TBWca-uw 34.6 +/- 7.6 L. At a population level, there is agreement between prediction of TBW in patients with pancreatic cancer estimated from the three equations. The best combination of low bias and narrow limits of agreement was observed when TBW was estimated from the equation developed in the underweight cancer patients relative to the normal weight cancer patients. When no established BIA prediction equation exists, practitioners should utilize an equation developed in a population with similar critical characteristics such as diagnosis, weight loss, body mass index and/or age. Conclusions Further research is required to determine the accuracy of the BIA prediction technique against a reference method in patients with pancreatic cancer.

Modernity Contextualises New Zealand's Royal Commission on Genetic Modification: A Discourse Analysis

The New Zealand's Royal Commission on Genetic Modification (RCGM)'s report was released in the year 2001. RCGM's findings supports the ongoing development of genetic engineering in New Zealand and recommends the recommencement of genetic modification field trials.