Divergence in female calling song discrimination between sympatric and allopatric populations of the southern wood cricket Gryllus fultoni (Orthoptera: Gryllidae)

Two species of closely related wood cricket, Gryllus fultoni (Orthoptera: Gryllidae) and Gryllus vernalis, occur together in some parts of the eastern United States and have a similar calling song structure, consisting of three-pulse chirps. A previous study revealed that chirp rate in G. fultoni was highest (greatest difference vis-à-vis chirp rate in G. vernalis) in sympatric populations, intermediate in near allopatric populations that were located close to the sympatric zone, and lowest in allopatric populations. A similar trend was observed in pulse rate, but the mean values of this trait showed much more convergence than chirp rate at the low end of the range of calling temperatures. In this study, we investigated the song discrimination of females from sympatric and allopatric populations of G. fultoni at about 23°C, which is near the middle of the normal range of calling temperatures. We used both single-stimulus and two-stimulus playback experiments to learn if geographical differences in song preferences paralleled those in calling songs. Stimuli presented were representative of calling songs in three classes of G. fultoni populations (sympatric, near allopatric, and far allopatric), a calling song of G. vernalis, and three calling songs with parameter values that were intermediate with respect to those of the songs of far allopatric G. fultoni and G. vernalis. In the single-stimulus playbacks, females of all G. fultoni populations responded poorly if at all to the heterospecific stimulus. Females of sympatric and near allopatric populations responded poorly to all intermediate stimuli, but females of far allopatric populations frequently responded to these sounds. In the two-stimulus playbacks, females of sympatric and near allopatric populations generally discriminated against intermediate and heterospecific stimuli. However, females of far allopatric populations often did not discriminate against intermediate stimuli, whose characteristics resembled the calling songs of G. vernalis. The divergent pattern of female phonotactic discrimination between sympatric and far allopatric populations was thus generally congruent with the pattern of divergence in chirp and pulse rates and would be expected to significantly reduce heterospecific mating in sympatry. These geographical patterns of female song discrimination and male calling songs conform to a commonly used definition of reproductive character displacement.     

Compressibility of municipal solid waste codisposed with fly ash

If a municipal solid waste (MSW) landfill is used as the foundation for a construction site, the change in the loading conditions may cause considerable compression of the landfill. Therefore, reinforcement to compensate for the loose compression nature of a MSW landfill is a very important design factor for geotechnical engineers when considering the end-use of the landfill. In this study, we discuss a possible technique for stabilizing MSW landfills through the codisposal of municipal solid waste and fly ash. To estimate the stabilization based on the compression characteristics of the codisposed landfill, we performed tests using a large compression set and experimental cells. According to the test results, if the proportion of fly ash is increased, initial and long-term compression could be reduced.     

Predicting Debris Yield From Burned Watersheds: Comparison of Statistical and Artificial Neural Network Models1

Abstract: Alluvial fans in southern California are continuously being developed for residential, industrial, commercial, and agricultural purposes. Development and alteration of alluvial fans often require consideration of mud and debris flows from burned mountain watersheds. Accurate prediction of sediment (hyper‐concentrated sediment or debris) yield is essential for the design, operation, and maintenance of debris basins to safeguard properly the general population. This paper presents results based on a statistical model and Artificial Neural Network (ANN) models. The models predict sediment yield caused by storms following wildfire events in burned mountainous watersheds. Both sediment yield prediction models have been developed for use in relatively small watersheds (50‐800 ha) in the greater Los Angeles area. The statistical model was developed using multiple regression analysis on sediment yield data collected from 1938 to 1983. Following the multiple regression analysis, a method for multi‐sequence sediment yield prediction under burned watershed conditions was developed. The statistical model was then calibrated based on 17 years of sediment yield, fire, and precipitation data collected between 1984 and 2000. The present study also evaluated ANN models created to predict the sediment yields. The training of the ANN models utilized single storm event data generated for the 17‐year period between 1984 and 2000 as the training input data. Training patterns and neural network architectures were varied to further study the ANN performance. Results from these models were compared with the available field data obtained from several debris basins within Los Angeles County. Both predictive models were then applied for hind‐casting the sediment prediction of several post 2000 events. Both the statistical and ANN models yield remarkably consistent results when compared with the measured field data. The results show that these models are very useful tools for predicting sediment yield sequences. The results can be used for scheduling cleanout operation of debris basins. It can be of great help in the planning of emergency response for burned areas to minimize the damage to properties and lives.     

Highly siliceous MCM-48 from rice husk ash for CO2 adsorption

Mesoporous MCM-48 silica was synthesized using a cationic-neutral surfactant mixture as the structure-directing template and rice husk ash (RHA) as the silica source. The MCM-48 samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N₂ physisorption and SEM. X-ray diffraction pattern of the resulting MCM-48 revealed typical pattern of cubic Ia3d mesophase. BET results showed the MCM-48 to have a surface area of 1024 m²/g and FT-IR revealed a silanol functional group at about 3460 cm⁻¹. Breakthrough experiments in the presence of MCM-48 were also carried out to test the material's CO₂ adsorption capacity. The breakthrough time for CO₂ was found to decrease as the temperature increased from 298 K to 348 K. The steep slopes observed shows the CO₂ adsorption occurred very quickly, with only a minimal mass transfer effect and very fast kinetics. In addition, amine grafted MCM-48, APTS-MCM-48 (RHA), was prepared with the 3-aminopropyltriethoxysilane (APTS) to investigate the effect of amine functional group in CO₂ separation. An order of magnitude higher CO₂ adsorption capacity was obtained in the presence of APTS-MCM-48 (RHA) compared to that with MCM-48 (RHA). These results suggest that MCM-48 synthesized from rice husk ash could be usefully applied for CO₂ removal.     

Application of TRIZ creativity intensification approach to chemical process safety

This study develops a modified method of TRIZ to improve safety in chemical process design. This method is modified by the theory of TRIZ, which is inventive problem solving theory, for retrofit design of chemical process considering safety.The original TRIZ is difficult to access to chemical process safety due to inapplicability and ambiguity of terminology in classification of these parameters. It is necessary to be modified TRIZ for chemical process safety. This study reorganized thirty-nine parameters of the TRIZ into six categories such as mechanic, operator, process upset, design, natural hazard and material. The modified TRIZ is tested to jacketed reactor and polyethylene reactor.     

Behavior of PAHs from sewage sludge incinerators in Korea

Although production of sewage sludge increases every year, its proper treatment has only been recently raised as a new issue, as current landfill and ocean dumping arrangements are expected to become increasingly difficult to manage in the future. The Korean Ministry of Environment plans to diversify its processing facilities and expand its processing systems by 2011, with the purpose of processing all sludge produced in Korea. According to this plan, incineration (including incineration of municipal wastes) will process 30% of the entire sewage sludge throughout the country in 2011. This study reviews the characteristics of PAH, which is one of the organic substances found in sewage sludge during the incinerating process. The total amount of PAH produced from sewage sludge incineration was found to be 6.103 mg/kg on average, and investigation performed on 16 PAHs of inlets and outlets of the air control devices at five full-scale incineration facilities showed that concentrations of the PAHs on the inlet and on the outlet ranged from 3.926 to 925.748 microg/m(3) and from 1.153 to 189.449 microg/m(3), respectively. In the case of the incineration facility fed with municipal waste (95%) and sewage sludge (5%), the total of the PAH emissions concentration was higher than that found at the incineration facilities used exclusively to treat sewage. The combustion of waste vinyl and plastics contained in municipal waste fed into the facility might contribute to the high levels of PAHs in the stack gas. However more investigation is needed on the production mechanism of PAHs at different operating conditions of the incineration facilities, such as the types of waste, and other relevant factors.     

Effect of silver nanoparticles in crop plants Phaseolus radiatus and Sorghum bicolor: media effect on phytotoxicity

Understanding some adverse effects of nanoparticles in edible crop plants is a matter of importance because nanoparticles are often released into soil environments. We investigated the phytotoxicity of silver nanoparticles (AgNPs) on the important crop plants, Phaseolus radiatus and Sorghum bicolor. The silver nanoparticles were selected for this study because of their OECD designation as a priority nanomaterial. The toxicity and bioavailability of AgNPs in the crop plant species P. radiatus and S. bicolor were evaluated in both agar and soil media. The seedling growth of test species was adversely affected by exposure to AgNPs. We found evidence of nanoparticle uptake by plants using electron microscopic studies. In the agar tests, P. radiatus and S. bicolor showed a concentration dependent-growth inhibition effect. Measurements of the growth rate of P. radiatus were not affected in the soil studies by impediment within the concentrations tested herein. Bioavailability of nanoparticles was reduced in the soil, and the dissolved silver ion effect also differed in the soil as compared to the agar. The properties of nanoparticles have been shown to change in soil, so this phenomenon has been attributed to the reduced toxicity of AgNPs to plants in soil medium. The application of nanoparticles in soil is a matter of great importance to elucidate the terrestrial toxicity of nanoparticles.     

Monitoring of environmental contaminants in raw bovine milk and estimates of dietary intakes of children in South Korea

Persistent organic pollutants (POPs) are ubiquitous residual contaminants in the environment and in the food chain. Milk is an important matrix for monitoring POP contamination. This study determined the concentrations of POPs including polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (DL-PCBs) in raw bovine milk, and the data was used to estimate dietary intakes in South Korea. The average concentrations of PBDEs, HCB, PCDD/Fs, and DL-PCBs in raw milk were 0.29 ng g⁻¹ fat, 0.50 ng g⁻¹ fat, 0.27 pg TEQ g⁻¹ fat, and 0.33 pg TEQ g⁻¹ fat, respectively. No significant relationship was found between the concentrations of analytes and the regions sampled. The dietary intakes of PBDEs from the consumption of milk was calculated to be 0.26, 0.10, and 0.05 ng kg⁻¹ bw d⁻¹ for the group of ages 0–6, 7–12, and 13–19, respectively. The dietary intakes of HCB was calculated to be 0.44, 0.16, and 0.09 ng kg⁻¹ bw d⁻¹ for the group of ages 0–6, 7–12, and 13–19, respectively. The dietary intakes of PCDD/Fs and DL-PCBs was calculated to be 0.78, 0.29, and 0.16 pg TEQ kg⁻¹ bw d⁻¹ for the group of ages 0–6, 7–12, and 13–19, respectively. These results indicated that the residual levels of PBDEs, HCB, PCDD/Fs, and DL-PCBs in raw bovine milk were within safe levels.     

Residual Perchloroethylene in Dry-Cleaned Acetate: The Effect of Pressing and Extent of Inter-Dry-Cleaner Variability

ABSTRACT

Measurements of residual perchloroethylene (PCE), a dry-cleaning solvent associated with human health effects, were made in dry-cleaned acetate cloth to enable improved characterizations of both occupational and environmental exposure. A limited sample size (25 acetate cloths) was used to explore the extent of inter-dry-cleaner variability in residual PCE and to characterize the effect of the pressing operation on residual PCE. A new method, which uses carbon-disulfide as the direct extracting agent, proved effective in the analysis of residual PCE, with a recovery-efficiency ≈ 75%. Inter-dry-cleaner variability of residual PCE, although marginally statistically significant, was relatively low, showing only a fourfold range compared to a 5-order-of-magnitude range obtained from Kawauchi and Nishiyama¹. Pairwise comparison of residual PCE in nonpressed versus pressed acetate samples revealed a statistically significant reduction (p < 0.008), which amounted to a consistent (among dry-cleaners) pressing-related removal efficiency of 75 ± 4%. A preliminary assessment of the source term associated with the pressing operation (mass PCE liberated per kg cloth dry-cleaned, S_PCE ≈ 30 mg/kg) indicates a minor contribution to the average ambient air concentrations within dry-cleaning establishments.     

Analysis of Long-Term Settlement of Municipal Solid Waste Landfills as Determined by Various Settlement Estimation Methods

Abstract

In this study, several existing municipal solid waste (MSW) settlement estimation methods are reviewed and applied to analyze the settlement data of nine MSW land-fills. Because a biodegradation-related settlement contributes differently to a long-term total settlement depending on the age of landfills, the actual MSW landfill sites are classified into three groups to specifically address the validity of each method in its prediction of a long-term settlement for each age category. Results demonstrate that there are considerable decreases in predicted settlement potentials as fill age increases. Comparisons indicate that the individual estimation methods display a considerable variation in predicting settlements in the fresh MSW landfills. On the other hand, for the old refuse landfills, all of the estimation methods, except the extended soil model, predict low settlement potentials.