Prediction of household and commercial BMW generation according to socio-economic and other factors for the Dublin region

Both planning and design of integrated municipal solid waste management systems require accurate prediction of waste generation. This research predicted the quantity and distribution of biodegradable municipal waste (BMW) generation within a diverse ‘landscape’ of residential areas, as well as from a variety of commercial establishments (restaurants, hotels, hospitals, etc.) in the Dublin (Ireland) region. Socio-economic variables, housing types, and the sizes and main activities of commercial establishments were hypothesized as the key determinants contributing to the spatial variability of BMW generation. A geographical information system (GIS) ‘model’ of BMW generation was created using ArcMap, a component of ArcGIS 9. Statistical data including socio-economic status and household size were mapped on an electoral district basis. Historical research and data from scientific literature were used to assign BMW generation rates to residential and commercial establishments. These predictions were combined to give overall BMW estimates for the region, which can aid waste planning and policy decisions. This technique will also aid the design of future waste management strategies, leading to policy and practice alterations as a function of demographic changes and development. The household prediction technique gave a more accurate overall estimate of household waste generation than did the social class technique. Both techniques produced estimates that differed from the reported local authority data; however, given that local authority reported figures for the region are below the national average, with some of the waste generated from apartment complexes being reported as commercial waste, predictions arising from this research are believed to be closer to actual waste generation than a comparison to reported data would suggest. By changing the input data, this estimation tool can be adapted for use in other locations. Although focusing on waste in the Dublin region, this method of waste prediction can have significant potential benefits if a universal method can be found to apply it effectively.     

Intranest relatedness and nestmate recognition in the meadow ant Formica pratensis (R.)

The impact of intranest relatedness on nestmate recognition was tested in a population of polydomous and monodomous nests of the mound-building ant Formica pratensis. Nestmate recognition was evaluated by testing aggression levels between 37 pairs of nests (n=206 tests). Workers from donor colonies were placed on the mounds of recipient nests to score aggressive interactions among workers. A total of 555 workers from 27 nests were genotyped using four DNA microsatellites. The genetic and spatial distances of nests were positively correlated, indicating budding and/or fissioning as spread mechanisms. Monodomous and polydomous nests did not show different aggression levels. Aggression behavior between nests was positively correlated with both spatial distance and intranest relatedness of recipient colonies, but not with genetic distance or intranest relatedness of donor colonies. Multiple regression analysis revealed a stronger effect of spatial distance than of genetics on aggression behavior in this study, indicating that the relative importance of environment and genetics can be variable in F. pratensis. Nevertheless, the positive regression between intranest relatedness of recipient colonies and aggression in the multiple analysis supports earlier results that nestmate recognition is genetically influenced in F. pratensis and further indicates that foreign label rejection most likely explains our data.     

A method for the assessment of light-induced oxidative stress in embryos of fucoid algae via confocal laserscan microscopy

A method was developed for measurement of active oxygen production in embryonic stages of the brown seaweed Fucus spiralis, using the label CM-DCFH-DA. Active oxygen species convert the label into the green fluorescent CM-DCF (exc/em 488/530 nm) that is detected via confocal laserscan microscopy and quantitative image analysis. Loading of the label did not harm the embryos; loading efficiency was age-independent, and the esterases needed for conversion to CM-DCFH were not inhibited by the effective UV dose (2 W m⁻²) applied in the experiments. After correction for daily variation of the laser power, and calibration with DCF standard solutions, this automated analysis of confocal images rendered active oxygen concentrations in fucoid embryos (μM DCF). An experiment was designed for the assessment of active oxygen production following irradiance stress in the light-sensitive embryos. Dim-light-acclimated, 1-, 2- and 4-day-old embryos were transferred for 60 min to defined high-light conditions (4π-irradiance 300 μmol photons m⁻² s⁻¹), optionally without UV radiation, including UVA, or including UVA plus UVB. PSII yield measurements (PAM fluorometer) were carried out in order to assess the degree of photoinhibition under these light conditions. The imposed light stress initially caused a rapid decrease of the PSII yields (Φ_P). With increasing embryo age, minimum Φ_P values attained under light stress remained higher. Consequently, electron transport rates (ETR) would increase with embryo age, i.e., with the development of their photosynthetic apparatus. Active oxygen production increased with ETR, and when UVB was included, relatively greater amounts of active oxygen were produced. A slow, second-phase decrease of Φ_P under light stress that was proportional to active oxygen production indicated that some photooxidative damage was caused, in particular during UVB exposure. Recovery from light stress was a rapid process in the absence of UVB; in such cases Φ_P was almost restored to the initial values within 60 min. The relative state of recovery of Φ_P was correlated with both the effective UV dose and active oxygen production rate (DCF). Recovery was slowest in embryos exposed for 60 min to an experimental UVB dose, which was representative of a situation at low tide, on a sunny day. The results suggest that active oxygen may cause an in situ inhibition of growth of the earliest life stages of F. spiralis. Received: 26 January 2000 / Accepted: 4 September 2000     

Development of some natural matrix standards — Progress report

Substantial progress has been made in the production of environmental level, natural matrix, radioactivity standards of soil of low organic and low carbonate content, and of human lung and human liver. This is in response to the deliberations of the 1977 ICRM meeting at which the need for such standards was voiced and the criteria suggested. The soil samples have been reduced to optimum particle size and are ready for blending and standardization. A ten year supply of this standard should be ready in a year or less. Reducing the dried lung and liver to less than 74 μm has proven formidable because of the natural fat and oil content. Using cyrogenic milling techniques more than three quarters of the total mass of each has been reduced to the desired particle size; the balance will either be reduced or removed and we can then proceed to the final standardization.