Effect of unburned carbon content in fly ash on the retention of 12 elements out of coal-combustion flue gas

The aim of this study was to evaluate whether unburned carbon particles present in fly ash can help in the retention of S, Cl, Br, As, Se, Cu, Ni, Zn, Ga, Ge, Rb, and Pb out of flue gas during the coal combustion at fluidised-bed power station where the coal was combusted along with limestone. The competitive influence of 10%-25% CaO in fly ashes on the distribution of studied elements was studied as well to be clear which factor governs behaviour of studied elements. Except of S (with significant association with CaO) and Rb and Pb (with major affinity to Al₂O₃) the statistically significant and positive correlation coefficients were calculated for the relations between unburned carbon content and Br (0.959), Cl (0.957), Cu (0.916), Se (0.898), Ni (0.866), As (0.861), Zn (0.742), Ge (0.717), and Ga (0.588) content. The results suggest that the unburned carbon is promising material in terms of flue gas cleaning even if contained in highly calcareous fly ashes.     

The effect of female arrivals on mate monopolization in the yellow dung fly

The degree of resource monopolization relates to the distribution of resources in space and time. In general, monopolization is predicted to be high when resources (food or mates) are clumped in space, dispersed in time, and predictable in space or time. Using the yellow dung fly, Scathophaga stercoraria (Diptera: Scathophagidae), we qualitatively tested a general model that predicts the distribution of mating success among competing males based on the temporal pattern of female arrivals relative to mating time and a ranking of males in priority of access to the resource (here by body size). In a laboratory experiment approximating the natural mating situation, a constant number of males of various sizes were allowed to compete for females. As predicted, mate monopolization decreased as the temporal clumping of female arrivals increased, mediated by either a decrease in the mean or an increase in the variance of female inter-arrival times, which were manipulated independently. Males appeared to adjust their behavior to variation in female arrivals in a manner consistent with the marginal value theory of Parker and associates: forcible take-overs of females were rarer, and copula durations shorter, when females arrived regularly at short intervals. Therefore, a complex interaction of variation in intrinsic characteristics affecting male resource holding potential, mating time and stochastic, extrinsic variables increasing temporal clumping of mates generally reduces the variance in mating success among competing males and thus ultimately the opportunity and intensity of sexual selection on traits influencing male success. This theory extends operational sex ratio theory at the mechanistic, behavioral level.     

Implications of processing spatial data from a forested catchment for a hillslope hydrological model

The objective of this study was to investigate with aid of a hillslope hydrological model (1) how landscape forms and land-use types control runoff generation and nitrogen leaching and (2) how the inevitable simplifications made when representing the entire catchment by a single hillslope (characteristic profile) affect modelled water and nitrogen fluxes. Analysis of the effect of hillslope shape parameters (e.g. length and slope) indicated that in forested hillslopes the modelled nitrogen export had a strong linear relationship with the share of subsurface runoff from the total runoff. The fraction of subsurface runoff, however, showed a non-linear relationship to changes in the profile length and slope. Decrease in length, and increase in slope, lead to a greater fraction of subsurface runoff. The non-linearity in the relationship implies that estimation of both the subsurface fraction and the nitrogen load is distorted when sub-areas producing large fractions of subsurface flow are aggregated with areas generating only little subsurface runoff into a single characteristic profile. In constructing the characteristic profile, aggregation of areas having different forest stand/soil properties causes the upslope drainage areas and the flow pathways to the stream to become distorted. The effects of such distortion were found to be particularly high for ammonium as its behaviour – due to efficient retention in soil – is highly non-linear with respect to the distance from the source area into the stream (i.e. size of buffer zone). In case of nitrate, which was considered not to be retained in soil, the role of groundwater table at the source area (clear-cut) was identified to be a more important control than the buffer zone size. As the upslope parts of a catchment have a significant role in determining the groundwater table at the treatment site, a question arises whether in addition to buffer zones one should also turn the attention upslope of the nitrogen source areas. Clearly patterns of landscape, such as distribution of nitrogen source areas in this study, pose challenges in selecting the spatial description for environmental simulation models. In nutrient leaching models, which easily become complex when based on process descriptions, compromises are needed to trade off between model complexity and the way how realistically landscape is described.     

Female dispersal and reproductive success in wild western lowland gorillas (<Emphasis Type="Italic">Gorilla gorilla gorilla</Emphasis>)

This paper presents data on the dispersal patterns and reproductive success of western lowland gorilla females from a long-term study at Mbeli Bai in the Nouabalé-Ndoki National Park, Republic of Congo. We find that female natal and secondary transfer is common. Female immigration rates are negatively related to group size, and emigration rates are positively related to group size, with the net result that larger groups are losing females and smaller groups are gaining females. Furthermore, females transferring between known groups show a preference for significantly smaller groups. However, there is no effect of group size on female reproductive success. Male protection and male quality are considered important in determining female transfer decisions. The case for infanticide is argued and females exhibit strategies that appear to minimise the probability of infanticide following the death of the silverback. Exclusively single-male groups and group formation through female acquisition by solitary males may bias female transfer to lone silverbacks and small groups. The effects of group size on female dispersal and reproductive success are not wholly consistent with an argument for increased foraging costs, and group size effects are more parsimoniously explained by demographic factors. Male protection from intra-group aggression is the most likely factor underlying grouping patterns across gorilla taxa, but differences in population structure and male reproductive strategies may account for inter-specific variation. We stress the need for intra-specific comparisons and more complete data sets on western lowland gorilla feeding behaviour.Communicated by S. Boinski     

Dechlorination ability of municipal waste incineration fly ash for polychlorinated phenols

Pathways of pentachlorophenol dechlorination have been investigated on municipal waste incineration fly ash at 200 degrees C under nitrogen atmosphere. Thermodynamic calculations have been carried out for these dechlorination conditions using the method of total Gibbs energy minimization for the whole system consisting of gaseous components, i.e., chlorinated phenols, phenol, hydrogen chloride and the Cu3Cl3 trimer and of solid Cu2O and CuCl2 components. The effects of water, temperature and of the amounts of the reaction components on the thermodynamic equilibrium have been discussed and the experimental results compared with the calculated thermodynamic data.