A near real-time system for continuously monitoring airborne subtilisin-type enzymes in the industrial atmosphere

We describe the development and validation of a portable system comprising an air sampler coupled to an automated flow injection analysis device. The system is able to monitor airborne concentrations of subtilisin-type enzymes in the workplace atmosphere on a continuous basis. Sampling is in two stages: using a sampling head that is designed to mimic human respiration at approx. 1 m s(-1) at a sampling rate of 600 l min(-1). In the second stage, the captured particles are deposited by impaction from the air stream onto the inner surface of a cyclone that is continuously washed with a jet of buffer solution. Deposited particles are then washed into a reservoir from which samples are taken every 5-6 min and injected automatically into a continuous flow injection analysis system. Proteolytic enzyme in the sample passes through a bioreactor maintained at about 40 degrees C. This contains a cellulose solid phase matrix on which is covalently immobilised Texas Red-labelled gelatin as substrate. The passing enzyme partially digests the substrate releasing fluorophore that is detected down stream in a flow cell coupled to a fluorimeter. The system is calibrated using enzyme standards and the intensity of the resulting peaks from the ex-air samples is converted to airborne concentrations using a mathematical model programmed into a PC. The system has a limit of detection of 4.8 ng m(-3) and a dynamic range of 5-60 ng m(-3). The within assay precision (RSD) is 6.3-9.6% over this range. The within batch precision is 20.3% at 20 ng m(-3) and the corresponding between batch value is 19.5%. The system has been run for periods up to 8 h in the laboratory and for up to 4 h at a factory site and the values obtained compared with time-averaged values obtained from a conventional Galley sampler and in-house analysis when reasonable agreement of the results was observed. The stability of the system over 21 days of continuous use with standards injected periodically was studied. Linearity was observed for all the standard plots throughout. At the end of 21 days, after a total exposure equivalent to 2395 ng ml(-1) of Savinase, the signal due to the 5.0 ng ml(-1) standard was still easily detectable.     

Acute physiological reactions of Calanus pacificus to selected dinoflagellates: direct observations

Calanus pacificus (Copepoda: Calanoida) females were collected off the California (USA) coast from November 1984–April 1985. A video system was used to observe and record the behavior of restrained individual females presented with a variety of dinoflagellate prey. Two species, Gonyaulax grindleyi and Ptychodiscus brevis, elicited acute physiological reactions. In 40% of the trials (n=10), copepods fed G. grindleyi regurgitated after 45 to 120 min and, in nearly all cases, did not maintain full guts. Copepods in the presence of P. brevis exhibited rapid heart rate and loss of motor control. Scrippsiella trochoidea elicited an intermediate response by C. pacificus. The copepods occasionally displayed mouthpart twitching or failure to maintain gut fullness. Olisthodiscus luteus elicited no unusual behavior in an intermediate temporal range (sec-hours), although the mouthpart movements appeared different than in copepods fed Gyrodinium resplendens (used as control). Placing the copepods in G. resplendens suspension restored normal feeding behavior in all cases.     

Asymmetric larval competition in the parasitoid wasp <Emphasis Type="Italic">Nasonia vitripennis</Emphasis>: a role in sex allocation?

Sex allocation theory offers excellent opportunities for testing how animals adjust their behaviour in response to environmental conditions. A major focus has been on instances of local mate competition (LMC), where female-biased broods are produced to maximise mating opportunities for sons. However, the predictions of LMC theory can be altered if there is both local competition for resources during development and an asymmetry between the competitive abilities of the sexes, as has been seen in animals ranging from wasps to birds. In this paper, we test the extent to which asymmetric larval competition alters the predictions of LMC theory in the parasitoid wasp Nasonia vitripennis. We found that the body size of both sexes was negatively correlated with the number of offspring developing within the host. Further, we found that when faced with high levels of competition, the body size of females, but not males, was influenced by the sex ratio of the competing offspring; females were smaller when a higher proportion of the brood was female. This asymmetric competition should favour less biased sex ratios than are predicted by standard LMC theory. We then develop a theoretical model that can be parameterised with our data, allowing us to determine the quantitative consequences of the observed level of asymmetric larval competition for sex allocation. We found that although asymmetric competition selects for less biased sex ratios, this effect is negligible compared to LMC. Furthermore, a similar conclusion is reached when we re-analyse existing data from another parasitoid species where asymmetric larval competition has been observed; Bracon hebetor. Consequently, we suspect that asymmetric larval competition will have its greatest influence on sex ratio evolution in species that have smaller clutches and where local mate competition is not an issue, such as birds and mammals.     

Male influence on sex allocation in the parasitoid wasp Nasonia vitripennis

Sex allocation is an important reproductive decision for parents. However, it is often assumed that females have substantial control over sex allocation decisions, and this is particularly true in haplodiploid insects, in which females apparently determine sex by deciding whether to fertilise an egg (and produce a diploid daughter) or not (and produce a haploid son). Mechanisms by which males may influence sex allocation are not so straightforward, and their potential influence on sex ratios has been somewhat neglected. Here, we test whether males influence offspring sex ratios in the parasitoid wasp Nasonia vitripennis. We show that some of the variation in observed sex ratios can be attributed to males when comparing the affect of male strain on sex ratio. We did not find among-male variation in sex ratio with a less powerful experiment using males from only one strain or an effect of male mating environment. Our data suggest that males can influence female sex ratios and contribute to the variation around the sex ratios optimal for females. However, the influence is not large, suggesting that females have more influence on sex allocation than do males. We conclude by considering whether male influences on sex ratio represent differences in male reproductive competence or deliberate attempts by males to increase their fitness by influencing daughter production.     

Youth environmental attitudes in Australia and Brunei: implications for education

This paper explores similarities and differences in the knowledge, beliefs and actions that comprise the environmental attitudes of senior secondary school students in Australia and Brunei. Utilising data from a wider international study in Asia and the Pacific (Yencken et al. , 2000), the paper uses findings from these two countries to illustrate the pervasiveness of global environmental concerns over local cultural influences in the construction of youth environmental attitudes in Australia and Brunei. Thus, young people in these countries, as they do in all parts of the Asia-Pacific region, have very similar levels of environmental awareness and knowledge, sources of environmental, beliefs, systems or world views about the environment, and levels of perceived control over environmental trends. They also have a shared desire for schools to do more in the area of environmental education. The paper concludes that much more effort needs to be made in certain areas. The first is to encourage teachers and others who have influence over young people to develop their own knowledge and skills to be able to teach environmental education effectively. The second is in the area of curriculum and pedagogical reform so that young people explore the many possible ways in which current systems can change to support sustainability, in which current lifestyles reflect these systems, and in which their own actions can contribute to a sustainable future.     

INTEGRATION OF WATER QUALITY MODELING,REMOTE SENSING,AND GIS1

ABSTRACT: Water quality modeling has been developed for more than three quarters of a century, but is limited to the study of trends instead of making accurate short-term forecasts. A major barrier to water quality forecasting is the lack of an efficient system for water quality monitoring. Traditional water quality sampling is time-consuming, expensive, and can only be taken for small sizes. Remote sensing provides a new technique to monitor water quality repetitively for a large area. The objective of this research is to use remotely sensed data in a water quality model - QUAL2E - in a case study of the Te-Chi Reservoir in Taiwan. The water quality variables developed from the simulations are displayed in map form. The developed forecasting system is designed to predict water quality variables using remote sensing data as an input to initialize and update water quality conditions.     

Linking Fine-Scale Sub-Arctic Vegetation Distribution in Complex Topography with Surface-Air-Temperature Modelled at 50-m Resolution

This article presents the impact of the ecological investment in ironworks (dust filter installation) and construction works at a highly contaminated brownfield site on the chemical composition of household dust (HD) and street sediment (SS) in Celje, Slovenia. The evaluation is based on two sampling campaigns: the first was undertaken 1 month before the ecological investment became operational and the second 3 years later. The results show that dust filter installations reduced the content of Co, Cr, Fe, Mn, Mo, W and Zn on average by 58% in HD and by 51% in SS. No reduction was observed at sampling points in the upwind direction from the ironworks. By contrast, the impact of the construction works on the highly contaminated brownfield site was detected by a significant increase (on average by 37%) of elements connected to the brownfield contamination in SS. Such increase was not detected in HD.     

Simple screening models of NAPL dissolution in the subsurface

Three simple screening models of nonaqueous phase liquid (NAPL) dissolution in the subsurface are proposed based on the NAPL mass conservation and the assumption of proportionality between the residual NAPL source zone concentration and the remaining residual NAPL mass. The purpose of the proposed models is to predict the solute concentration in the zone of the residual NAPL as a result of dissolution. The predicted source zone concentration decrease is used to simulate and account for the decrease of dissolution rate with time. The proposed simple NAPL dissolution models enable the pseudo-equilibrium formulation to be used and therefore the numerical simulations for field application problems can be simplified compared to the non-equilibrium counterpart. With proper choice of empirical parameters, the proposed simple screening models can work as well as more complex dissolution rate correlation models, such as that of Imhoff et al. [Water Resour. Res. 30 (1994) 307-320]. It is found that the proposed models are very good for quantifying non-equilibrium dissolution, which is characterized by tailing of breakthrough curves. The models are especially useful for situations of small residual NAPL saturation, which are typical for many field applications.