Associative learning for danger avoidance nullifies innate positive chemotaxis to host olfactory stimuli in a parasitic wasp

Animals rely on associative learning for a wide range of purposes, including danger avoidance. This has been demonstrated for several insects, including cockroaches, mosquitoes, drosophilid flies, paper wasps, stingless bees, bumblebees and honeybees, but less is known for parasitic wasps. We tested the ability of Psyttalia concolor (Hymenoptera: Braconidae) females to associate different dosages of two innately attractive host-induced plant volatiles (HIPVs), ethyl octanoate and decanal, with danger (electric shocks). We conducted an associative treatment involving odours and shocks and two non-associative controls involving shocks but not odours and odours but not shocks. In shock-only and odour-only trained wasps, females preferred on HIPV-treated than on blank discs. In associative-trained wasps, however, P. concolor’s innate positive chemotaxis for HIPVs was nullified (lowest HIPV dosage tested) or reversed (highest HIPV dosage tested). This is the first report of associative learning of olfactory cues for danger avoidance in parasitic wasps, showing that the effects of learning can override innate positive chemotaxes.     

Comparison of different disinfection processes in the effective removal of antibiotic-resistant bacteria and genes

This study compared three different disinfection processes(chlorination, E-beam, and ozone) and the efficacy of three oxidants(H2O2, S2O-8, and peroxymonosulfate(MPS)) in removing antibiotic resistant bacteria(ARB) and antibiotic resistance genes(ARGs) in a synthetic wastewater. More than30 mg/L of chlorine was needed to remove over 90% of ARB and ARG. For the E-beam method, only1 dose(kGy) was needed to remove ARB and ARG, and ozone could reduce ARB and ARG by more than 90% even at 3 mg/L ozone concentration. In the ozone process, CT values(concentration × time)were compared for ozone alone and combined with different catalysts based on the 2-log removal of ARB and ARG. Ozone treatment yielded a value of 31 and 33(mg·min)/L for ARB and ARGs respectively. On the other hand, ozone with persulfate yielded 15.9 and 18.5(mg·min)/L while ozone with monopersulfate yielded a value of 12 and 14.5(mg·min)/L. This implies that the addition of these catalysts significantly reduces the contact time to achieve a 2-log removal, thus enhancing the process in terms of its kinetics.     

Transformation of a landfill covering amended with municipal waste compost, Perugia, Italy

This research deals with the transformation of an anthropomorphous landfill covering composed of a fill soil mixed with mechanically separated municipal waste compost. The study site was a municipal landfill near Perugia, Italy. Throughout the years, waste disposal in the landfill was performed by burial in horizontal layers, each one representing a yearly disposal. The external front of the landfill thus represented the yearly disposal over a 10-yr period starting in 1993. Temporal changes in the anthropomorphous soil over this period were studied by examining and describing soil profiles, and by collecting and analyzing soil samples from the 1993, 1994, 1997, and 2001 disposals. The samples were subjected to a series of physical, chemical, and biochemical analyses. The results obtained suggest that over a 10-yr period the top layer gained a pedological structure (subangular blocky and/or crumb) giving rise to an A horizon. Improved soil structure was confirmed by an increase in macroporosity, particularly for pores larger than 50 microm, measured by image analysis of soil thin sections. Total extractable carbon showed an increase in the content of humic substances, evidenced by parameters of humification. Enzymatic activities in the A and C1 horizons were also indicative of soil evolution and may serve as a valid indicator for monitoring the evolution of anthropogenic soils containing municipal waste compost.     

Spatial Relationships Between Water Quality and Pesticide Application Rates in Agricultural Watersheds

Pesticide applications to agricultural lands in California, USA, are reported to a central data base, while data on water and sediment quality are collected by a number of monitoring programs. Data from both sources are geo-referenced, allowing spatial analysis of relationships between pesticide application rates and the chemical and biological condition of water bodies. This study collected data from 12 watersheds, selected to represent a range of pesticide usage. Water quality parameters were measured during six surveys of stream sites receiving runoff from the selected watershed areas. This study had three objectives: to evaluate the usefulness of pesticide application data in selecting regional monitoring sites, to provide information for generating and testing hypotheses about pesticide fate and effects, and to determine whether in-stream nitrate concentration was a useful surrogate indicator for regional monitoring of toxic substances. Significant correlations were observed between pesticide application rates and in-stream pesticide concentrations (p < 0.05) and toxicity (p < 0.10). In-stream nitrate concentrations were not significantly correlated with either the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.30). Neither total watershed area nor the area in which pesticide usage was reported correlated significantly with the amount of pesticides applied, in-stream pesticide concentrations, or in-stream toxicity (all p > 0.14). In-stream pesticide concentrations and effects were more closely related to the intensity of pesticide use than to the area under cultivation.     

Aquaculture expansion in Brazilian freshwaters against the Aichi Biodiversity Targets

The Convention on Biological Diversity proposed the Aichi Biodiversity Targets to improve conservation policies and to balance economic development, social welfare, and the maintenance of biodiversity/ecosystem services. Brazil is a signatory of the Aichi Biodiversity Targets and is the most diverse country in terms of freshwater fish, but its national policies have supported the development of unsustainable commercial and ornamental aquaculture, which has led to serious disturbances to inland ecosystems and natural resources. We analyzed the development of Brazilian aquaculture to show how current aquaculture expansion conflicts with all 20 Aichi Targets. This case suggests that Brazil and many other megadiverse developing countries will not meet international conservation targets, stressing the need for new strategies, such as the environmental management system, to improve biodiversity conservation.     

Adsorption mechanism of chromium(III) using biosorbents of Jatropha curcas L.

Environmental Science and Pollution Research - The removal of Cr3+ from water solutions by biosorbents from the rind, endosperm, and endosperm + episperm of the Jatropha curcas was evaluated....     

Co-solvent selection and recovery

The selection and recovery of two or more solvents (i.e. co-solvents) are studied because of their importance in environmentally responsible processing. A particularly challenging problem arises when the contaminants (or solutes) are comprised of a mixture of volatile and nonvolatile compounds. The nonvolatile components present difficulties in solvent selection while the volatile components give rise to solvent recovery challenges. Traditional approaches such as the Kauri-Butanol test and predictions based on solubility parameters from regular solution theory can result in poor solvent selection when some of the contaminants are nonvolatile. A simple, graphical and rigorous procedure based on Gibbs energies of mixing for all binary mixtures of solvents and contaminants is proposed for choosing solvent/contaminant pairs. This selection procedure is based on the choice of solvent resulting in the lowest solvent/contaminant Gibbs free energy of mixing for a given contaminant. Nonvolatile contaminants are often easily separated in a single-stage flash vessel. Volatile contaminants, on the other hand, can form homogeneous or heterogeneous azeotropes with commonly used solvents, give rise to distillation boundaries and result in a challenging co-solvent recovery problem. A systematic procedure for the synthesis, design and economic analysis for co-solvent recovery is presented. Residue curve maps are used to identify distillation boundaries and to generate a conceptual process flow sheet for co-solvent recovery. Equipment sizes for the separators and auxiliaries (i.e. condensers, reboilers, decanters, etc.) are determined and capital investment, installation and operating costs are calculated. The removal of oil-water emulsions from the surface of machined metal parts using n-propyl bromide (NPB) and isopropyl alcohol (IPA) in a closed-loop degreaser is used to illustrate the proposed methodology of co-solvent selection and recovery. Analysis shows that the Kauri-Butanol test and the use of solubility parameters can result in poor solvent selection. In contrast, the proposed methodology shows that NPB is competitive with banned solvents like chlorodifluoro, fluorodichloroethane and trichloroethane and highly regulated solvents such as perchloroethylene, trichloroethylene and is a good solvent for the removal of machining oils while IPA is a good solvent for removing water. Separation of mixtures of NPB/IPA/water is difficult because of the presence of three binary and one ternary azeotrope that create three distinct distillation regions as well as regions of vapor-liquid-liquid behavior. It is shown that these distillation boundaries preclude direct water separation and that a two-distillation sequence with decantation is required to cross boundaries and recover both solvents. A variety of geometric illustrations are presented to elucidate key concepts.     

Geostatistical strategy for soil sampling: the survey and the census

A soil sampling strategy for spatially correlated variables using the tools of geostatistical analysis is developed. With a minimum of equations, the logic of geostatistical analysis is traced from the modeling of a semi-variogram to the output isomaps of pollution estimates and their standard deviations. These algorithms provide a method to balance precision, accuracy, and costs. Their axiomatic assumptions dictate a two-stage sampling strategy. The first stage is a sampling survey, using a radial gird, to collect enough data to define, by a semi-variogram, the ranges of influence and the orientation of the correlation structure of the pollutant plume. The second stage is a census of the suspected area with grid shape, sizes and orientation dictated by the semi-variogram. The subsequent kriging analysis of this data gives isopleth maps of the pollution field and the standard error isomap of this contouring. These outputs make the monitoring data understandable for the decision maker.