A comparative study of aggressiveness in eastern North American field cricket species (genus <Emphasis Type="Italic">Gryllus</Emphasis>)

To understand the variation in aggressiveness and factors important for contest outcome, we quantified and compared agonistic interactions of four field cricket species in eastern North America: Gryllus fultoni (Orthoptera; Gryllidae), G. vernalis, G. pennsylvanicus, and G. rubens. The most aggressive behavior that we observed, the grapple, was frequently displayed in agonistic trials of G. pennsylvanicus and G. rubens. By contrast, we never observed this behavior in trials involving G. fultoni and G. vernalis. Consequently, species was the only significant variable affecting the variation in aggressiveness, whereas size difference, age difference, and contest duration had no significant effect. In species with high levels of aggressiveness, G. pennsylvanicus and G. rubens, the factors that might be indicative of resource holding potential such as size or age difference seemed to be significant for contest outcome. In species with low levels of aggressiveness, G. fultoni and G. vernalis, however, there were indications that contest outcomes were determined by aggressiveness itself rather than the size and age differences between opponents. Markov chain analyses revealed that the difference in aggressiveness between species with high and low levels of aggressiveness lay in a sequence of escalating behaviors: antennal fencing, mandible flare, and grapple. The escalated state of aggressiveness characterized by this behavioral sequence in G. pennsylvanicus and G. rubens seems to be the ancestral state in the North American Gryllus phylogeny. We argue that the loss of a tendency to use burrows in G. fultoni and G. vernalis might be related to low levels of aggressiveness in these species.     

Towards a Simple Indicator of Biodiversity

Policy makers in Canada have suggested that the scientific community should develop an indicator of biodiversity change that can be implemented quite quickly without a major new investment in monitoring systems. We propose that such an indicator can be developed from the theory of species gradients in community ecology. The term 'species gradients' refers to the increasing diversity of species through time under stable conditions, and the increasing diversity of species with the increased use of available resources. This theory is reviewed under four different headings: evolutionary ecology, the energy theory, the resource productivity theory and the thermodynamic mechanism. The theoretical arguments provide a basis to propose detection of the 'leaky ecosystem' as an indicator of biodiversity. We propose that it is possible to detect the leaky energetics of ecosystems by means of routinely available observations of outgoing longwave radiation.     

Assessment of natural and calcined starfish for the amelioration of acidic soil

Quality improvement of acidic soil (with an initial pH of approximately 4.5) with respect to soil pH, exchangeable cations, organic matter content, and maize growth was attempted using natural (NSF) and calcined starfish (CSF). Acidic soil was amended with NSF and CSF in the range of 1 to 10 wt.% to improve soil pH, organic matter content, and exchangeable cations. Following the treatment, the soil pH was monitored for periods up to 3 months. The exchangeable cations were measured after 1 month of curing. After a curing period of 1 month, the maize growth experiment was performed with selected treated samples to evaluate the effectiveness of the treatment. The results show that 1 wt.% of NSF and CSF (700 and 900 °C) were required to increase the soil pH to a value higher than 7. In the case of CSF (900 °C), 1 wt.% was sufficient to increase the soil pH value to 9 due to the strong alkalinity in the treatment. No significant changes in soil pHs were observed after 7 days of curing and up to 3 months of curing. Upon treatment, the cation exchange capacity values significantly increased as compared to the untreated samples. The organic content of the samples increased upon NSF treatment, but it remains virtually unchanged upon CSF treatment. Maize growth was greater in the treated samples rather than the untreated samples, except for the samples treated with 1 and 3 wt.% CSF (900 °C), where maize growth was limited due to strong alkalinity. This indicates that the amelioration of acidic soil using natural and calcined starfish is beneficial for plant growth as long as the application rate does not produce alkaline conditions outside the optimal pH range for maize growth.     

Thermal conductivity characteristics of dewatered sewage sludge by thermal hydrolysis reaction

The purpose of this study is to quantify the thermal conductivity of sewage sludge related to reaction temperature for the optimal design of a thermal hydrolysis reactor. We continuously quantified the thermal conductivity of dewatered sludge related to the reaction temperature. As the reaction temperature increased, the dewatered sludge is thermally liquefied under high temperature and pressure by the thermal hydrolysis reaction. Therefore, the bound water in the sludge cells comes out as free water, which changes the dewatered sludge from a solid phase to slurry in a liquid phase. As a result, the thermal conductivity of the sludge was more than 2.64 times lower than that of the water at 20℃. However, above 200℃, it became 0.704 W/m?°C, which is about 4% higher than that of water. As a result, the change in physical properties due to thermal hydrolysis appears to be an important factor for heat transfer efficiency.

ImplicationsThe thermal conductivity of dewatered sludge is an important factor the optimal design of a thermal hydrolysis reactor. The dewatered sludge is thermally liquefied under high temperature and pressure by the thermal hydrolysis reaction. The liquid phase slurry has a higher thermal conductivity than pure water.     

Effect of chemical amendments on remediation of potentially toxic trace elements (PTEs) and soil quality improvement in paddy fields

Remediation of potentially toxic trace elements (PTEs) in paddy fields is fundamental for crop safety. In situ application of chemical amendments has been widely adapted because of its cost-effectiveness and environmental safety. The main purpose of this research was to (1) evaluate the reduction in dissolved concentrations of cadmium (Cd) and arsenic (As) with the application of chemical amendments and (2) monitor microbial activity in the soil to determine the remediation efficiency. Three different chemical amendments, lime stone, steel slag, and acid mine drainage sludge, were applied to paddy fields, and rice (Oryza sativa L. Milyang 23) was cultivated. The application of chemical amendments immobilized both Cd and As in soil. Between the two PTEs, As reduction was significant (p < 0.05) with the addition of chemical amendments, whereas no significant reduction was observed for Cd than that for the control. Among six soil-related variables, PTE concentration showed a negative correlation with soil pH (r = ?0.70 for As and r = ?0.54 for Cd) and soil respiration (SR) (r = ?0.88 for As and r = ?0.45 for Cd). This result indicated that immobilization of PTEs in soil is dependent on soil pH and reduces PTE toxicity. Overall, the application of chemical amendments could be utilized for decreasing PTE (As and Cd) bioavailability and increasing microbial activity in the soil.     

Thermoeconomic installation limit of PV/WT hybrid energy systems for Off-grid islands

An ideal off-grid island can become 100% energy-sufficient if one installs renewable energy systems such as solar photovoltaic (PV) and wind turbine (WT) systems. However, the intermittent and uncertain nature of the power supply from renewable energy systems hinders a 100% autonomy level (AL) without an infinite energy storage capacity. The thermoeconomic installation limit (TEIL) of a PV/WT hybrid energy system was studied using hourly weather data and the energy demand profile for off-grid islands. An appropriate battery size for the TEIL was also determined. Given the current installation cost of the hybrid energy system and the battery unit, the AL for a PV/WT hybrid energy system at the TEIL is calculated to be approximately 70%. Above the limit, the size of the energy storage unit and, correspondingly, the total annual cost of the PV/WT hybrid energy system increase sharply.     

The application and development of country-specific parameters for accurate estimations of methane emissions from solid-waste disposal sites

To identify the application and development of country-specific parameters for methane emission estimations from solid-waste disposal sites, National Inventory Reports of 41 Annex I countries and National Communications of ten non-Annex I countries of the United Nations Framework Convention on Climate Change were analyzed. A first-order decay method was applied to 38 out of 41 Annex I countries and to five out of ten non-Annex I countries in national GHG inventory submissions up to 2012. Country-specific parameters were approximately 26 % of the total number of parameters used in the 38 Annex I countries and were mostly developed for degradable organic carbon and reaction constants that cover certain waste compositions. The UNFCCC encourages countries to develop more country-specific parameters reflecting the distinct characteristics of each country in which solid-waste disposal site is a key source. Depending on a country’s condition, a stepwise approach regarding the development of country-specific parameters needs to be done so as to improve the accuracy of methane emission estimates in the solid-waste disposal site category.     

Nitrate-contaminated groundwater remediation by combined autotrophic and heterotrophic denitrification for sulfate and pH control: batch tests

Groundwater remediation was evaluated for combined autotrophic and heterotrophic denitrification under high (154 mg/L as CaCO₃) and low (95 mg/L as CaCO₃) alkaline conditions. Two levels of acetate (47 and 94 mg/L) and ethanol (24 and 48 mg/L) were added to the reactors. Obtained denitrification rates were 2.89, 2.58, 3.55, 1.96, and 2.0 mg-N/L?·?h for high alkaline conditions, whereas under low alkaline conditions has given 2.36, 1.94, 2.47, 2.74, and 2.29 mg-N/L?·?h for control, 47 and 94 mg/L acetate, and 24 and 48 mg/L ethanol, respectively. Nitrite was accumulated for controls but reactors with acetate and ethanol did not accumulate nitrite. Acetate and ethanol addition decreased sulfate to nitrate ratios in the range of 4.5–7.58 for high alkaline conditions (12.77 for control) and 4.43–6.78 for low alkaline conditions (7.90 for control). Acetate was more efficient compared with ethanol in controlling sulfate production and pH maintenance.     

Effect of in vitro administered 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on DNA-binding activities of nuclear transcription factors in NIH-3T3 mouse fibroblasts

Abstract

Most modern pesticides are expensive. Application of excessive dosage rates is likely to cause undesirable biological side‐effects and is economically wasteful. Non‐uniform distribution of the spray cloud, or application at the wrong time, may result in failure to control the pest. It is the responsibility of the field operator to acquire sufficient knowledge and skill to ensure proper use of the control agents, to increase efficiency of their usage and to reduce unwanted side‐effects. To achieve this goal, he must take into consideration the various physical factors that govern field performance of pesticides.

A simple relationship exists between the spray volume and emission rate used, and droplet size produced. The use of extremely low spray volumes (i.e., those less than 2.0 litre per ha) for forest insect control in Canada, as opposed to higher volumes used in agriculture, necessitates the release of fine droplets (ranging from 20 to 70 μm in diameter) to obtain adequate coverage of the target area. These droplets take a long time to sediment downwards, evaporate in‐flight, become smaller in size and/or form powdery residues, thus contributing to off‐target drift and impaired droplet adhesion to target surfaces. Physical factors such as rain washing, degradation by sunlight and erosion by wind also influence the longevity of pesticide deposits on foliage which is crucial during the critical period of pest control.

Factors affecting the mode of entry into insects are related to the type of ingredients used in formulation. If a pesticide acts via crawling contact, formulations which would provide surface deposits would be more beneficial than emulsions or oil‐based mixes which tend to undergo penetration into foliar cuticle. Physical factors that affect field performance of a pesticide tank mix are related to phase separation and ‘breakdown of emulsions’ in the application equipment; ‘agglomeration and caking’ of wettable powder dispersions at the bottom of the tank; impaired flow behaviour of highly viscous formulations; and coarse atomization of high‐viscosity tank mixes leading to poor target cover.     

Significance of autochthonous Bacillus sp. KK1 on biomineralization of lead in mine tailings

The aim of the study was to isolate and characterize potential autochthonous bacteria for biomineralization of Pb in mine tailings. A total of four bacteria were isolated from the soil samples and assayed for tolerance to Pb and other heavy metals. Isolate KK1 exhibited maximum Pb resistance and was subsequently identified as Bacillus sp. based on the partial 16S rRNA gene sequences. The isolate KK1 reduced the Pb ions and did not harbor pbrT gene. Selective sequential extraction of bioaugmented soil revealed that the isolate significantly reduced (26%) the exchangeable fraction and increased (38%) the carbonate fraction of Pb. X-ray diffraction studies confirmed the role of bacterially induced calcite precipitation in the bioremediation of mine tailings. A significant increase in the urease (334%), DHO (dehydrogenase) (14%), and phosphatase (37%) activity was observed in the bioaugmented mine soil.