REGIONAL RUNOFF SIMULATION FOR SOUTHEAST MICHIGAN1

ABSTRACT: The feasibility of simulating monthly runoff for southeast Michigan, which comprises four major river basins, was evaluated with the Streamflow Synthesis and Reservoir Regulation watershed model. The evaluation covered a 13-year period (1961–73), which encompassed a complete runoff cycle. Results indicate it is feasible to simulate monthly runoff volumes on a regional scale with a single equivalent watershed by using daily precipitation and temperature data. Simulation of regional flows appears particularly attractive for the Great Lakes basin, since the basin consists of many relatively small watersheds. This method also appears promising for development of monthly runoff forecasts by employing average monthly meteorological data distributed on a daily basis. Tests of six-month runoff forecasts show relatively small deterioration with time and offer considerable improvement over climatology.     

Biomass waste gasification - can be the two stage process suitable for tar reduction and power generation?

A pilot scale gasification unit with novel co-current, updraft arrangement in the first stage and counter-current downdraft in the second stage was developed and exploited for studying effects of two stage gasification in comparison with one stage gasification of biomass (wood pellets) on fuel gas composition and attainable gas purity. Significant producer gas parameters (gas composition, heating value, content of tar compounds, content of inorganic gas impurities) were compared for the two stage and the one stage method of the gasification arrangement with only the upward moving bed (co-current updraft). The main novel features of the gasifier conception include grate-less reactor, upward moving bed of biomass particles (e.g. pellets) by means of a screw elevator with changeable rotational speed and gradual expanding diameter of the cylindrical reactor in the part above the upper end of the screw. The gasifier concept and arrangement are considered convenient for thermal power range 100-350 kW_th. The second stage of the gasifier served mainly for tar compounds destruction/reforming by increased temperature (around 950 °C) and for gasification reaction of the fuel gas with char. The second stage used additional combustion of the fuel gas by preheated secondary air for attaining higher temperature and faster gasification of the remaining char from the first stage. The measurements of gas composition and tar compound contents confirmed superiority of the two stage gasification system, drastic decrease of aromatic compounds with two and higher number of benzene rings by 1-2 orders. On the other hand the two stage gasification (with overall ER = 0.71) led to substantial reduction of gas heating value (LHV = 3.15 MJ/Nm³), elevation of gas volume and increase of nitrogen content in fuel gas. The increased temperature (>950 °C) at the entrance to the char bed caused also substantial decrease of ammonia content in fuel gas. The char with higher content of ash leaving the second stage presented only few mass% of the inlet biomass stream.     

Evaluation of offshore emergency preparedness in view of rare accidents

The offshore industry in the North Sea has gone from a very high risk level for employees some 30–40 years ago, to a low level. The paper reviews the statistics briefly and discusses the implications of the low level. There has from the beginning of the operations been strong focus on emergency preparedness, due to the remoteness of the operations mostly far from shore. But there will always have to be a balance between the focus on preventative safety efforts and the extent of emergency preparedness provisions. This is discussed in detail, based on an extensive evaluation of the adequacy of emergency preparedness provisions recently performed. The main findings are presented, and the robustness and validity of the approach is discussed, together with implications of the rare major accidents.     

Effect of a mixture of flufenacet and isoxaflutole on population numbers of soil-dwelling microorganisms,enzymatic activity of soil,and maize yield

Abstract

This study was aimed to evaluate the effect of a mixture of flufenacet?+?isoxaflutole on counts of microorganisms, ecophysiological diversity index (EP), colony development index (CD) and on the enzymatic activity of soil and maize growth. The experiment was conducted with sandy clay, to which the tested herbicide was administered in doses of: 0.25, 5.0, 10, 20, 40, 80 and 160?mg/kg. Soil without the addition of the mixture served as the control. Results demonstrated that the tested mixture contributed to a decrease in numbers of Azotobacter, organotrophic bacteria, actinobacteria and fungi. The negative effect of the herbicide could also be noticed in the case of the enzymatic activity of soil. Soil contamination contributed to suppressed activities of dehydrogenases, catalase, urease, alkaline phosphatase and arylsulfatase. In turn, the initial increase in the activity of β-glucosidase was followed by its decline observed with time. The flufenacet?+?isoxaflutole mixture affected also maize plant growth, reducing maize dry matter yield when used at doses from 5.0 to 160?mg/kg. In summary, it may be concluded that mixture evokes a negative effect on the microbiological and biochemical activity of soil and that their excess in the soil leads to plant decay as at the seeding stage.     

Multiple insemination increases reproductive success of female Montandon’s newt (<Emphasis Type="Italic">Triturus montandoni</Emphasis>, Caudata,Salamandridae)

The adaptive significance of multiple matings for females is a matter of much controversy. In insects, supplying the female’s sperm reserves with portions of fresh spermatozoa may be the main function of multiple matings. This simple explanation may also be applied to other animals which produce large numbers of eggs over prolonged periods of time. We tested the fertility insurance hypothesis in Montandon’s newt (Triturus montandoni, Amphibia, Salamandridae). T. montandoni females are inseminated internally by spermatophores they have picked up, and subsequently lay eggs fertilized by spermatozoa released from the spermatheca. We compared the reproductive success of singly and multiply inseminated females of Montandon’s newt in the laboratory. Multiply inseminated females laid more eggs and had a lower percentage of non-developing eggs than females who mated only once. Our data suggest that remating increases the reproductive success of multiply inseminated females by replenishing sperm reserves in the spermatheca or by supplying females with fresh portions of spermatozoa with high fertilizing capacity. Received: 7 January 2000 / Revised: 13 September 2000 / Accepted: 7 October 2000     

No evidence that sperm morphology predicts paternity success in wild house wrens

Postcopulatory sexual selection (PCSS) in internally fertilizing vertebrates is a topic of great interest, yet relatively little is known about the characteristics of sperm and ejaculates that confer an advantage in PCSS. In this study, we investigated several measures of sperm morphology that potentially contribute to fertilization success under PCSS. We tested whether sperm morphology related to success in PCSS (via extra-pair paternity) in house wrens (Troglodytes aedon). We found no evidence that sperm morphology differed between extra-pair sires and the within-pair males they cuckolded, nor that sperm morphology correlated with the proportion of within-pair offspring sired, the number of extra-pair offspring sired, or the total annual reproductive success. Male behavioral strategies may affect the probability that their sperm compete with other males’ sperm and that their sperm succeed under competition. Effects of these behavioral strategies, as well as differences between males in sperm number, could mask the effects of sperm morphology on the outcome of PCSS. Despite moderate levels of extra-pair paternity, selection on sperm may be relatively weak in house wrens. Further work is needed to understand general patterns in how sperm morphology relates to fertilization success within species.     

Do biodiversity indices behave as expected from traits of constituent species in simulated scenarios?

It is believed that diversity of plant communities has a positive effect on their productivity. The benefits of diversity are described by “biodiversity indices”, comparing yield of mixtures with yields of monocultures of constituent species. These indices are supposed to capture also the main mechanisms leading to increased yield. We have constructed a spatially explicit individual based model, simulating even-aged stand development, and compared the behaviour of selected biodiversity indices (overyielding, selectivity and complementarity) with expectations based on life history traits of constituent species. The results are based on comparisons of two species mixtures with corresponding monocultures. We designed three scenarios of changes in the two species life history differentiation, and compared the behaviour of the indices with expectation based on it. In the first scenario, selectivity was driven by increasing size inequality of the two species, mostly in accordance with expectations. The second scenario presents increasing shade tolerance of the smaller species that increased complementarity, again mostly as expected. In the last scenario, shortening of length of stress tolerance of the weaker species surprisingly increased values of the biodiversity indices. For each setting, we varied sowing density and spatial pattern of the constituent species. The behaviour of the indices was influenced by both factors, but the effect of density was more pronounced. In particular, at high sowing densities, the most important interactions happened in the very early stages of mixture development, and the behaviour of the indices was often counter-intuitive.     

Do female association preferences predict the likelihood of reproduction?

Sexual selection acting on male traits through female mate choice is commonly inferred from female association preferences in dichotomous mate choice experiments. However, there are surprisingly few empirical demonstrations that such association preferences predict the likelihood of females reproducing with a particular male. This information is essential to confirm association preferences as good predictors of mate choice. We used green swordtails (Xiphophorus helleri) to test whether association preferences predict the likelihood of a female reproducing with a male. Females were tested for a preference for long- or short-sworded males in a standard dichotomous choice experiment and then allowed free access to either their preferred or non-preferred male. If females subsequently failed to produce fry, they were provided a second unfamiliar male with similar sword length to the first male. Females were more likely to reproduce with preferred than non-preferred males, but for those that reproduced, neither the status (preferred/non-preferred) nor the sword length (long/short) of the male had an effect on brood size or relative investment in growth by the female. There was no overall preference based on sword length in this study, but male sword length did affect likelihood of reproduction, with females more likely to reproduce with long- than short-sworded males (independent of preference for such males in earlier choice tests). These results suggest that female association preferences are good indicators of female mate choice but that ornament characteristics of the male are also important.