Sludge population optimisation: a new dimension for the control of biological wastewater treatment systems

The activated sludge comprises a complex microbiological community. The structure (what types of microorganisms are present) and function (what can the organisms do and at what rates) of this community are determined by external physico -chemical features and by the influent to the sewage treatment plant. The external features we can manipulate but rarely the influent. Conventional control and operational strategies optimise activated sludge processes more as a chemical system than as a biological one. While optimising the process in a short time period, these strategies may deteriorate the long-term performance of the process due to their potentially adverse impact on the microbial properties. Through briefly reviewing the evidence available in the literature that plant design and operation affect both the structure and function of the microbial community in activated sludge, we propose to add sludge population optimisation as a new dimension to the control of biological wastewater treatment systems. We stress that optimising the microbial community structure and property should be an explicit aim for the design and operation of a treatment plant. The major limitations to sludge population optimisation revolve around inadequate microbiological data, specifically community structure, function and kinetic data. However, molecular microbiological methods that strive to provide that data are being developed rapidly. The combination of these methods with the conventional approaches for kinetic study is briefly discussed. The most pressing research questions pertaining to sludge population optimisation are outlined. (C) 2002 Elsevier Science Ltd. All rights reserved.

Avian paramyxoviruses and influenza viruses isolated from mallard ducks (Anas platyrhynchos) in New Zealand

A comprehensive study using virological and serological approaches was carried out to determine the status of live healthy mallard ducks (Anas platyrhynchos) in New Zealand for infections with avian paramyxoviruses (APMV) and influenza viruses (AIV). Thirty-three viruses isolated from 321 tracheal and cloacal swabs were characterized as: 6 AIV (two H5N2 and four H4N6), 10 APMV-1 and 17 APMV-4. Of 335 sera samples tested for AIV antibodies, 109 (32.5%) sera were positive by nucleoprotein-blocking ELISA (NP-B-ELISA). Serum samples (315) were examined for antibody to APMV-1, -2, -3, -4, -6, -7, -8, -9 by the haemagglutination inhibition test. The largest number of reactions, with titres up to greater than or equal to 1/64, was to APMV-1 (93.1%), followed by APMV-6 (85.1%), APMV-8 (56%), APMV-4 (51.7%), APMV-7 (47%), APMV-9 (15.9%), APMV-2 (13.3%) and APMV-3 (6.0%). All of the H5N2 isolates of AIV and the APMV-1 isolates from this and earlier New Zealand studies had low pathogenicity indices assessed by the Intravenous Pathogenicity Index (IVPI) with the result 0.00 and Intracerebral Pathogenicity Index (ICPI) with results 0.00-0.16. Partial genomic and antigenic analyses were also consistent with the isolates being non-pathogenic. Phylogenetic analysis of the 10 APMV-1 isolates showed 9 to be most similar to the reference APMV-1 strain D26/76 originally isolated in Japan and also to the Que/66 strain, which was isolated in Australia. The other isolate was very similar to a virus (MC 110/77) obtained from a shelduck in France.

The Limits of Rational Choice: New Institutionalism in the Test Bed of Central Banking Politics in Australia

This paper tests the explanatory capacities of different versions of new institutionalism by examining the Australian case of a general transition in central banking practice and monetary politics: namely, the increased emphasis on low inflation and central bank independence. Standard versions of rational choice institutionalism largely dominate the literature on the politics of central banking, but this approach (here termed RC1) fails to account for Australian empirics. RC1 has a tendency to establish actor preferences exogenously to the analysis; actors' motives are also assumed a priori; actor's preferences are depicted in relatively static, ahistorical terms. And there is the tendency, even a methodological requirement, to assume relatively simple motives and preference sets among actors, in part because of the game theoretic nature of RC1 reasoning. It is possible to build a more accurate rational choice model by re-specifying and essentially updating the context, incentives and choice sets that have driven rational choice in this case. Enter RC2. However, this move subtly introduces methodological shifts and new theoretical challenges. By contrast, historical institutionalism uses an inductive methodology. Compared with deduction, it is arguably better able to deal with complexity and nuance. It also utilises a dynamic, historical approach, and specifies (dynamically) endogenous preference formation by interpretive actors. Historical institutionalism is also able to more easily incorporate a wider set of key explanatory variables and incorporate wider social aggregates. Hence, it is argued that historical institutionalism is the preferred explanatory theory and methodology in this case.

Selenium content of Australian foods: A review of literature values

The aim of this study was to review the published literature values for the selenium content of Australian foods. A secondary aim was to compare the results for Australian foods with food composition data from international sources to investigate the extent of geographical variation. Published food composition data sources for the selenium content in Australian foods were identified and assessed for data quality using established criteria. The selenium content is available for 148 individual food items. The highest values found are for fish (12.0-63.2 mug/100 g), meats (4.75-37.9 mug/100 g) and eggs (9.00-41.4 mug/100 g), followed by cereals (1.00-20.3 mug/100 g). Moderate levels are seen in dairy products (2.00-7.89 mug/100 g) while most fruits and vegetables have low levels (trace-3.27 mug/100 g). High selenium foods show the greatest level of geographical variation, with foods from the United States generally having higher selenium levels than Australian foods and foods from the United Kingdom and New Zealand having lower levels. This is the first attempt to review the available literature for selenium composition of Australian foods. These data serve as an interim measure for the assessment of selenium intake for use in epidemiological studies of diet-disease relationships. (C) 2002 Published by Elsevier Science Ltd.

The Relative Frequency of the Synthetic End Composite Futures in the Newspaper Quest-France and some Observations on Distribution

Figures on the relative frequency of synthetic and composite future forms in Ouest-France are presented and compared with those of earlier studies on the passé simple and passé composé. The synthetic future is found to be dominant. Possible formal explanations for distribution are found to be inconclusive. Distribution across different text-types is found to be more promising, since contrastive functions of the two forms can be identified in texts where they co-occur. The composite future typically reports new proposals or plans as current news, while the synthetic future outlines details that will be realised at the time of implementation. Both functions are important in dailies, but current news is more often expressed in the present tense at the expense of the composite future.

Neonatal respiratory therapy in the new millennium: Does clinical practice reflect scientific evidence?

Respiratory therapy has historically been considered the primary role of the physiotherapist in neonatal intensive care in Australia. In 2001 a survey was undertaken of all level three neonatal intensive care units in Australia to determine the role of the physiotherapist and of respiratory therapy in clinical practice. It appears that respiratory therapy is provided infrequently, with the number of infants treated per month ranging from 0 to 10 in 15 of the 20 units who provide respiratory therapy, regardless of therapist availability. The median number of respiratory treatments per month during the week was three, and on weekends it was one. Respiratory therapy was carried out by physiotherapists and nurses in 54.6% of units, by physiotherapists only in 36.4% of units, and by nurses only in the remaining 9% of units surveyed. There was also a diminution of the role of respiratory therapy in the extubation of premature infants. A review of the literature shows that overall the use of respiratory therapy reflects current evidence. The question remains whether it is possible to maintain the competency of staff and justify the cost of training in the current healthcare economic climate. It seems probable that the future role of physiotherapists in neonatal intensive care unit may be in the facilitation of optimal neurological development of surviving very low birth weight infants.

New fluorescence parameters for monitoring photosynthesis in plants - 1. The effect of illumination on the fluorescence parameters of the JIP-test

Chlorophyll fluorescence measurements have a wide range of applications from basic understanding of photosynthesis functioning to plant environmental stress responses and direct assessments of plant health. The measured signal is the fluorescence intensity (expressed in relative units) and the most meaningful data are derived from the time dependent increase in fluorescence intensity achieved upon application of continuous bright light to a previously dark adapted sample. The fluorescence response changes over time and is termed the Kautsky curve or chlorophyll fluorescence transient. Recently, Strasser and Strasser (1995) formulated a group of fluorescence parameters, called the JIP-test, that quantify the stepwise flow of energy through Photosystem II, using input data from the fluorescence transient. The purpose of this study was to establish relationships between the biochemical reactions occurring in PS II and specific JIP-test parameters. This was approached using isolated systems that facilitated the addition of modifying agents, a PS II electron transport inhibitor, an electron acceptor and an uncoupler, whose effects on PS II activity are well documented in the literature. The alteration to PS II activity caused by each of these compounds could then be monitored through the JIP-test parameters and compared and contrasted with the literature. The known alteration in PS II activity of Chenopodium album atrazine resistant and sensitive biotypes was also used to gauge the effectiveness and sensitivity of the JIP-test. The information gained from the in vitro study was successfully applied to an in situ study. This is the first in a series of four papers. It shows that the trapping parameters of the JIP-test were most affected by illumination and that the reduction in trapping had a run-on effect to inhibit electron transport. When irradiance exposure proceeded to photoinhibition, the electron transport probability parameter was greatly reduced and dissipation significantly increased. These results illustrate the advantage of monitoring a number of fluorescence parameters over the use of just one, which is often the case when the F-V/F-M ratio is used.