Comprehensive Study Regarding Greenhouse Gas Emission from Iron Ore Based Production at the Integrated Steel Plant SSAB Tunnplåt AB

During the years 2001–2002, a comprehensive study regarding CO₂ emissions related to the steel production for the integrated steel making production route, was carried out. The study was financed by SSAB and carried out by a research group with members from SSAB, MEFOS and LTU. The aim was to study the emissions from the existing system and how these could be influenced by process changes and by process modifications. The calculations were made using a global spreadsheet model for calculating the CO₂ emissions, developed from an existing Energy and Process Integration model of the same system. The calculated cases included the existing BF/BOF route as well as integration of other processes, e.g., an electric arc furnace, DR processes, COREX and a new future smelting reduction process concept (Sidcomet). All new existing alternative ore based process technologies would increase the specific CO₂ emission from the system. A technology transfer to scrap based metallurgy would significantly decrease the emission level, but is not feasible for SSAB, due to the future product mix and the structure of scrap availability. In a 5–20 year perspective, the existing steel making process route with the use of magnetite ore for pellet production has the lowest specific CO₂ emission. In a long-term perspective, 20–50 years, alternative process routes, e.g., based on H₂ and DRI, could be of interest. Studies on such changes are, however, big projects and should be carried out as joint European and/or international efforts.     

Sexual selection and cues for female choice in leks of Jackson's widowbird Euplectes jacksoni

Summary Sexual selection through female mate choice was investigated in the lekking Jackson's widowbird by applying multivariate selection analysis to observational data from four leks. Males perform a stereotyped jump display on small display courts (dance rings) constructed by the males in open grassland. Females visit the lek solely for mating and nest on their own, away from the lek area. Few cases of interference during courtship and absence of position effects on mating success indicated that female choice within the leks was not pre-empted by male-male competition. In a set of 11 male traits with mating success as the dependent fitness measure, significant selection differentials (covariances) were found for the length of the conspicuous tail and the rate of the jump display, suggesting sexual selection of these traits. They also showed the largest selection gradients (partial effects) and thereby seem to be the cues on which females base their choice. The success of males in obtaining copulations appears to depend on two components: display rate and lek attendance affect the number of female visits, whereas tail length seems to primarily influence the chance of copulating with a visiting female. Tail length was positively related to a measure of body condition, which is of interest with regard to the suggestions that sexual ornaments may serve as indicators of male viability.     

Relationships of biological and taxonomic characteristics to chemically mediated bioactivity in Mediterranean littoral sponges

The aim of this study was to detect relationships of bioactive properties (antibacterial, antifungal, antiviral antimitotic and cytotoxic activities) of Mediterranean littoral sponges with some of their biological characteristics (growth habits, presence of symbiotic or epibiotic organisms, structural defences) and their systematic position. Antimitotic and cytotoxic activities were present in 80.6% and 73.6% of the species respectively, 42.2% of the species showed antibacterial activity, 29.8% were antiviral and 22.5% were antifungal. Only antiviral and antifungal activities were significantly dependent on taxonomical order, being especially important in the Axinellida. Antiviral, antifungal and antibacterial activities predominated in erect forms, and were poorly represented in encrusting forms, which, however, included a higher percentage of cytotoxic and antimitotic species. Nevertheless, only antiviral activity was significantly related to growth habit. All types of activities were significantly dependent on sponge skeletal features: the highest percentages of species with cytotoxic activity were found among horny and siliceous sponges. Also, antiviral and antibacterial activities were better represented in horny sponges. Antibacterial, antifungal and antiviral activities were dependent on the presence/absence of epibionts and seemed to be more efficient as antifouling defences than antimitotic and cytotoxic activities. Only cytotoxic activity was significantly more wide-spread in species harbouring cyanophyceae. Correspondence analysis revealed that cytotoxic and antimitotic activities were both related to encrusting forms, a siliceous skeleton, occasional epibiosis and the presence of cyanophyceae. Antifungal, antibacterial and antiviral activities were mainly related to erect or globular form, siliceous and horny skeleton and habitual (species-specific) epibiosis.