Male Scudderia pistillata katydids defend their acoustic duet against eavesdroppers

Acoustic duets—in which the female reveals herself to the advertising male—are a common means of establishing a temporary, pre-mating pair bond within Phaneropterinae katydids. Such duets, however, are especially susceptible to eavesdropping males that orient to signaling females and interrupt the established duet. It would therefore be advantageous for an advertising male to protect his investment in a duet from eavesdroppers. Male Scudderia pistillata katydids produce acoustic advertisement calls after which a conspecific female enters the duet by responding during a specific time-window with her own call, one or more acoustic ticks. We demonstrate here that when a duet is occurring in the presence of other calling males, the focal male produces a single acoustic tick that has a spectrum similar to that of the female’s tick and occurs during the time-window in which the female would respond to his advertisement call within the duet. The male acoustic tick may confound eavesdropping males if they have difficulty performing accurate phonotaxis to a female sound source when sounds arrive from two locations. We tested this hypothesis in laboratory arenas and determined that silent males eavesdrop on advertising male’s duets and accurately locate his female. Moreover, we found that the added acoustic tick produced by advertising males serves to mimic the female response and reduces the accuracy of eavesdropping males to localize the female. Therefore, male ticks appear to act as a form of pre-copulatory acoustic mate guarding of the calling male’s temporary pair bond with the female.     

Sustainable development control? Zoning and land use regulations for urban form,biodiversity conservation and green design in Australia

This paper examines how Australian land use plans incorporate provisions for sustainable urban form, design, biodiversity conservation, and climate change. Despite the long-standing sustainability objectives in state policy frameworks, a survey of 291 comprehensive plans finds implementation within local instruments is far from universal. Differences in patterns of policy adoption, as well as potential explanations for these differences, including geographical location, patterns of residential growth, the socio-economic composition of local communities, political forces, and policy evolution over time, are explored. Overall, areas experiencing more intensive growth tend to have newer plans, which in turn, contain more sustainability provisions, suggesting a responsive rather than repressive relationship between development pressures and regulatory development control.     

Electrolytic transformation of ordinance related compounds (ORCs) in groundwater: laboratory mass balance studies

Electrolytic reactive barriers (e(-) barriers) consist of closely spaced permeable electrodes installed across a groundwater contaminant plume in a permeable reactive barrier format. Application of sufficient potential to the electrodes results in sequential oxidation and reduction of the target contaminant. The objective of this study was to quantify the mass distribution of compounds produced during sequential electrolytic oxidation and reduction of ordinance related compounds (ORCs) in a laboratory analog to an e(-) barrier. In this study, a series of column tests were conducted using RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2,4,6-trinitrotoluene) as representative ORCs. The experimental setup consisted of a plexiglass column packed with quartz-feldspar sand to simulate aquifer conditions. A single set of porous electrodes consisting of expanded titanium-mixed metal oxide mesh was placed at the midpoint of the sand column as a one-dimensional analog to an e(-) barrier. Constant current of 20mA (variable voltage) was applied to the electrode set. Initial studies involved quantification of reaction products using unlabeled RDX and TNT. Approximately 70% of the influent concentration was transformed, in one pass, through sequential oxidation-reduction for both contaminants. Following the unlabeled studies, (14)C labeled RDX and TNT were introduced to determine the mass balance. An activity balance of up to 96% was achieved for both (14)C-RDX and (14)C-TNT. For both contaminants, approximately 21% of the influent activity was mineralized to (14)CO(2). The proportion of the initial activity in the dissolved fraction was different for the two test contaminants. Approximately 30% of the initial (14)C-RDX was recovered as unreacted in the dissolved phase. The balance of the (14)C-RDX was recovered as non-volatile, non-nitroso transformation products. None of the (14)C-RDX was sorbed to the column sand packing. For (14)C-TNT approximately 51% of the initial activity was recovered in the dissolved phase, the majority was unreacted TNT. The balance of the (14)C-TNT was either sorbed to the sand packing (approximately 24%) or dissolved/mineralized as unidentified ring cleavage products ( approximately 4%).     

Water-Quality Monitoring and Biological Integrity Assessment in the Indian River Lagoon, Florida: Status, Trends, and Loadings (1988–1994)

a production in the central, south central, and the south segments of the lagoon. In a system as large and complex as the lagoon, N and P limitations are potentially subject to significant spatial and temporal variability. Total Kjeldahl nitrogen (TN) was higher in the north (1.25 mg/liter) and lower in the south (0.89 mg/liter). The reverse pattern was observed for total P (TP), i.e., lowest in the north (0.03 mg/liter) and highest at the south (0.14 mg/liter) ends of the IRL. This increased P concentration in the SIRL appears to have a significantly large effect on chlorophyll a production compared with the other segments, as indicated by stepwise regression statistics. This relationship can be expressed as follows: South IRL [chlorophyll a] =−8.52 + 162.41 [orthophosphate] + 7.86 [total nitrogen] + 0.38 [turbidity]; R ²= 0.98**.     

A bench scale PVD remediation system experiment

Prefabricated vertical drains (PVDs) have been used for decades for soil improvement. Recent research has shown that PVDs can also be used to remediate contaminated fine-grained soils. A research program was undertaken at The University of Texas at Austin to study the use of PVDs in soil flushing (pump and treat). This research program included both analytical and experimental studies. The focus of this paper is the experimental part of the research effort. The design and results of two experiments are presented. These results provided insight into the operation and design of PVD remediation systems and exposed areas that need additional research. The laboratory results support prior research that indicate that PVD remediation systems can be an effective means of remediating contaminated fine-grained soils. In addition, the importance of keeping the injection and extraction rates similar to minimize consolidation was highlighted. The measured heads did not indicate that a significant amount of drawdown occurred over the course of the experiment. More research needs to be done on maintaining a consistent extraction rate and additional post experiment concentration measurements would be required if determining the tracer mass balance is the focus of any future experiments.     

Kriging for estimating spatial pattern of contaminants: Potential and problems

This paper discusses and illustrates the use of kriging techniques for estimating the spatial pattern of contaminants in environmental media, particularly soil. The assumptions underlying kriging are reviewed as are some advantages and disadvantages of the method. Lognormal kriging (kriging applied to logarithmic-transformed data) is illustrated using a set of radionuclide soil concentrations at a nuclear testing area on the Nevada Test Site. This example shows how lognormal kriging can be used to estimate average concentrations at points or for blocks of land, concentration contours over space, confidence bands about these contours, and radionuclide inventory in soil. The validity of kriging estimates depends on the accurate estimation and modeling of the spatial correlation structure of the phenomenon. Accuracy is especially important when lognormal kriging is used and estimates of means and their standard deviations are required in the original, untransformed scale. This paper illustrates the bias that can result when a changing correlation structure over space is ignored.Operated for the U.S. Department of Energy by Battelle Memorial InstituteWork supported by Nevada Applied Ecology Group, U.S. Department of Energy, Nevada Operations Office under Contract DE-AC06-76RLO 1830.     

Chronology of lead pollution contained in banded coral skeletons

Lead concentrations relative to calcium within dated subsamples of hermatypic (reef-building) coral skeletons from St. Croix, US Virgin Islands, record ambient pollution levels. Concentrations within a coral from a polluted reef (395 ng g^-1) average five-fold higher than within a coral from a pristine site (87 ng g^-1). The lead chronologies of both corals show a significant increase in concentration towards the present during the past 26 yr (1954–1980). The increase in lead concentration in the coral from the pristine site is suggested to represent the increase in lead availability from global pollution. Coral skeletons offer the probability of development into tools for longterm chemical recorders of levels of lead and possibly other metals or compounds in seawater.     

Pyrolysis and combustion of Aroclor 1254 contaminated dielectric fluids

Pyrolysis and combustion products were determined for several levels of PCB contamination in mineral oil and other dielectric fluids. Yields of PCDFs were roughly proportional to the quantity of PCB in the feed.