Bridging the gap between mechanistic and adaptive explanations of territory formation

How animals divide space can have fundamental implications for the population dynamics of territorial species. It has recently been proposed that space can be divided if animals tend to avoid fight locations, rather than the winner of fights gaining access to exclusive resources, behaviour that generates exclusive territories in two-dimensional space. A game-theory model has shown that this avoidance behaviour can be adaptive, but the adaptiveness has not been investigated in a spatially realistic context. We present a model that investigates potential strategies for the acquisition of territories when two-dimensional space must be divided between individuals. We examine whether exclusive territories form when animals avoid all encounters with others, or only those encounters that have led to losing fights, under different fighting costs and population densities. Our model suggests that when fighting costs are high, and the population density is low, the most adaptive behaviour is to avoid fight locations, which generates well-defined, exclusive territories in a population that is able to resist invasion by more aggressive strategies. Low fighting costs and high population densities lead to the break-down of territoriality and the formation of large, overlapping home ranges. We also provide a novel reason as to why so-called paradoxical strategies do not exist in nature: if we define a paradoxical strategy as an exact mirror-image of a common-sense one, it must respond in the opposite way to a draw as well as to wins and losses. When this is the case, and draws are common (fight outcomes are often not clear-cut in nature), the common-sense strategy is more often adaptive than a paradoxical alternative.Communicated by P. Bednekoff     

Uptake of radioiodide by Paenibacillus sp., Pseudomonas sp., Burkholderia sp. and Rhodococcus sp. isolated from a boreal nutrient-poor bog

Radionuclides, like radioiodine(~(129)I), may escape deep geological nuclear waste repositories and migrate to the surface ecosystems. In surface ecosystems, microorganisms can affect their movement. Iodide uptake of six bacterial strains belonging to the genera Paenibacillus,Pseudomonas, Burkholderia and Rhodococcus isolated from an acidic boreal nutrient-poor bog was tested. The tests were run in four different growth media at three temperatures. All bacterial strains removed iodide from the solution with the highest efficiency shown by one of the Paenibacillus strains with 99% of iodide removed from the solution in one of the used growth media. Pseudomonas, Rhodococcus and one of the two Paenibacillus strains showed highest iodide uptake in 1% yeast extract with maximum values for the distribution coefficient(K_d) ranging from 90 to 270 L/kg DW. The Burkholderia strain showed highest uptake in 1% Tryptone(maximum K_d170 L/kg DW). The Paenibacillus strain V0-1-LW showed exceptionally high uptake in 0.5% peptone + 0.25% yeast extract broth(maximum K_d 1,000,000 L/kg DW). Addition of 0.1% glucose to the 0.5% peptone + 0.25% yeast extract broth reduced iodide uptake at 4℃ and 20℃ and enhanced iodide uptake at 37℃ compared to the uptake without glucose. This indicates that the uptake of glucose and iodide may be competing processes in these bacteria. We estimated that in in situ conditions of the bog,the bacterial uptake of iodide accounts for approximately 0.1%–0.3% of the total sorption of iodide in the surface, subsurface peat, gyttja and clay layers.     

Unexpected bias of freeze-drying on the performance assessment of chemical oxidation of soils contaminated by polychlorinated biphenyls

Environmental Chemistry Letters - Processes based on chemical oxidation are widely used for environmental remediation. Analysis of environmental samples such as soils often requires a freeze-drying...     

Evaluation of Downwash Modifications to the Industrial Source Complex Model

The Industrial Source Complex (ISC) model has been modified to account for Improved understanding of plume rise and downwash around buildings. Two sets of observations are used to compare the modified and the original ISC models, showing that the new model better simulates the observed concentrations during high-wind conditions when downwash usually occurs.     

Procedures of trophic chain samples preparation for determination of triazines by HPLC and metals by ICP-AES methods

The aim of this research was monitoring the distribution of atrazine and simazine as well as metals Pb, Cd, Zn, Al, Co, Ni, and V along with trophic chains: soil-vegetables and soil, carrot or grass and meat. Different techniques of herbicides extraction by means of many solvents were examined. Triazines were analysed by means of HPLC, metals by means of ICP-AES. Detection limits: LOD=0.2 microg ml(-1), determination limits: LOQ=0.73 microg ml(-1) for atrazine and LOD=0.3 microg ml(-1), LOQ=1.12 microg ml(-1) for simazine were obtained. The content (microg g(-1)) of simazine in soil was in range: 3.45-8.60, in vegetable roots: 6.62-38.15, in vegetable leaves: 2.45-31.71, in rabbit fat: 0.13-49.90. The content (microg g(-1)) of atrazine in soils was in range: 11.9-13.03, in vegetable roots: 13.61-92.90. In analysed material the particular metals after microwave or dry digestion were determined in range (microg g(-1)): Pb: 6.48-43.18; Cd: 0.11-0.57; Zn: 8.79-51.90; Al: 10.22-24.48; Co: 0.18-3.89; Ni: 0.37-6.36; V: 0.29-1.48.