Sumo wrestling in ants: major workers fight over male production in<Emphasis Type="Italic"> Acanthomyrmex ferox</Emphasis>

In the myrmicine ant Acanthomyrmex ferox, major workers have the same number of ovarioles as queens, thrice that of minor workers, making them well suited for egg-laying. In the queen's presence, infrequent aggression allows ranking of majors but they lay only unviable trophic eggs. Major workers engage each other, but not the minors, in antennal boxing and spectacular shaking contests, a novel interaction in ants. The absence of reversals allows a clear ranking of major workers. After queen removal, aggression becomes very frequent, but previous ranking is maintained. All majors start laying reproductive eggs although they show a skew in ovary development according to ranking. The dominant major, however, actively patrols the egg-pile and cannibalises eggs laid by subordinates.     

Antimony in municipal waste.

Antimony content in municipal waste was studied. Sampled municipal waste was dried, crushed and analyzed. Antimony determinations were performed by Kjeldahl decomposition--batch hydride generation spectrometry and neutron activation analysis. Overall content of antimony in waste was 40-50 g/t raw waste. It was estimated than 20% of the annual production of antimony was discarded as municipal waste in Japan. Leaching of antimony from antimony-added materials may occur, because "small tips" involved considerable amounts of antimony.     

Evolutionary significance of prenuptial molting in female <Emphasis Type="Italic">Pagurus</Emphasis> hermit crabs

Molting and breeding entail major energetic costs for female crustaceans. However, females of some hermit crabs perform a molt immediately prior to copulation (prenuptial molt). The evolutionary significance of the prenuptial molt was examined in Pagurus hermit crabs, and two hypotheses were tested: (1) prenuptial molt might enhance the success of the present clutch by cleaning the pleopods of females and thereby preventing eggs from being dislodged from the pleopods, and (2) prenuptial molt might function for growth and increase future fecundity at the cost of energetic expenditure on the present brood. Although these hypotheses are not mutually exclusive, our results rejected the former hypothesis and supported the latter hypothesis. All four Pagurus species examined showed significant negative relationships between prenuptial molting and continuity of breeding; i.e., they showed high molting frequency after they had a long rest period from breeding. Females of P. minutus increased their size through the prenuptial molt, and showed a decreased clutch size due to the molt. The number of dislodged eggs increased if females molted in P. minutus. These results suggest that hermit crabs undergoing a prenuptial molt might not gain any clear immediate advantage of enhanced survival of eggs in the present clutch, and that the prenuptial molt would mainly contribute to growth.     

Closed-loop supply chain under different channel leaderships: considering different deposit–refund systems practically applied in China

Journal of Material Cycles and Waste Management - Different deposit–refund systems are being practically applied to promote the proper treatment of end-of-life products in China. One is...     

Photodecomposition of humic acid and natural organic matter in swamp water using a TiO2-coated ceramic foam filter: Potential for the formation of disinfection byproducts

This paper reports on the photodecomposition of aqueous humic acid (HA) by a TiO₂-coated ceramic foam filter (TCF) reactor and on the potential for the formation of disinfection byproducts (DBPs) upon chlorination of the photocatalytically treated solutions. This photocatalytic reactor can also be applied to the removal of natural organic matter (NOM) in swamp waters. The proposed photocatalytic reaction system was operated as per standardized methodologies. First, the ability of the TCF to decompose HA (a representative compound of NOM) was evaluated from the changes in the total organic carbon (TOC) and UV₂₅₄ with the reaction time. Remarkably, TOC removal and UV₂₅₄ values ranging from 44% to 61% and from 60% to 83%, respectively, were achieved. The potential for the formation of DBPs (total trihalomethane and total haloacetic acid) by chlorination of the phototreated solution was strongly dependent on the TOC removal and UV₂₅₄ values in the solution. The degree of photodecomposition of NOMs in the swamp water samples and the DBP formation potential showed similar trends as in the case of the standard solutions containing HA. The method used in this study could be effectively used to evaluate the efficiency of TCF for reducing HA and NOM, while suppressing the formation of DBP products.     

The flow structure in the wake of a fractal fence and the absence of an “inertial regime”

Recent theoretical work has highlighted the importance of multi-scale forcing of the flow for altering the nature of turbulence energy transfer and dissipation. In particular, fractal types of forcing have been studied. This is potentially of real significance in environmental fluid mechanics where multi-scale forcing is perhaps more common than the excitation of a specific mode. In this paper we report the first results studying the detail of the wake structure behind fences in a boundary layer where, for a constant porosity, we vary the average spacing of the struts and also introduce fractal fences. As expected, to first order, and in the far-wake region, in particular, the response of the fences is governed by their porosity. However, we show that there are some significant differences in the detail of the turbulent structure between the fractal and non-fractal fences and that these override differences in porosity. In the near wake, the structure of the fence dominates porosity effects and a modified wake interaction length seems to have potential for collapsing the data. With regards to the intermittency of the velocities, the fractal fences behave more similarly to homogeneous, isotropic turbulence. In addition, there is a high amount of dissipation for the fractal fences over scales that, based on the energy spectrum, should be dominated by inter-scale transfers. This latter result is consistent with numerical simulations of flow forced at multiple scales and shows that what appears to be an “inertial regime” cannot be as production and dissipation are both high.     

Evaluation of regional bioenergy recovery by local methane fermentation thermal recycling systems

This paper evaluates the potential for regional bioenergy recovery as electricity and heat by small-scale methane fermentation systems from organic waste matter generated from urban, industrial, and agricultural sectors. Biogas production functions of high-strength organic wastes are derived from data of implemented methane fermentation systems. The distributions of organic wastes from sewage, household, wholesale/retail, manufacturing, farming, and livestock activities in the Tokyo Bay region are calibrated into a disaggregated spatial database by compiling general activity statistics and emission intensity parameters using Geographic Information System (GIS). Three scenarios of organic matter circulation by co-digestion in sewage treatment plants (STPs) are designed and assessed. Surplus electricity and heat from methane fermentation systems are used for STP operations and household demand. The spatial database allows a preliminary examination for the suitability of locations for technology implementation from the aspects of bioenergy supply and balance. The results show that an additional 368,000-1,328,000MW of electricity would be generated, and 1300-3600TJ of heat could be used by households, reducing the annual emissions of CO(2) from fossil fuels by 307,000-798,000t.