Regional variation in queen and worker aggression in incipient colonies of the desert ant Messor pergandei

The fate of queen foundress associations in ants varies across taxa: in some, lethal fighting results in survival of a single queen, while in others, queens coexist long term. One hypothesis for this difference is that selection favors fighting when group sizes are small and tolerance when groups are large. In an experiment with the ant Messor pergandei, we formed small, medium, and large groups with newly mated queens from field populations that have different mean group sizes and differ in whether multiple queens occur in older established colonies. We found that whether queens are eliminated by fighting depends upon region of origin and not group size: regardless of co-foundress number, queens from sites with single-queen adult field colonies displayed agonistic behaviors and their colonies reduced to a single queen, while queens from sites with multiple-queen colonies did not fight and co-foundresses coexisted long term. Worker aggression towards and elimination of queens were also correlated with region of origin. Where fighting occurred, queens were as likely to be killed by workers as by other queens. An aggressive display was the most common form of agonistic interaction among queens, while fighting was relatively rare. We hypothesize that queen displays evolved in response to worker attacks because they increase the probability that workers will eliminate competitor queens. Our results suggest that the evolutionary interests of workers, as well as queens, could be important in determining the evolution and maintenance of queen elimination in foundress associations.     

Experimental and numerical investigation of confined explosion in a blast chamber

An experimental blast program consisting of four tests was conducted in a blast chamber to investigate the effects of cylindrical charges on the peak reflected overpressure and impulse on the wall of the chamber. The charge mass varied from 0.095 kg to 0.2 kg and the standoff distance remained constant at 1.5 m and 1.3 m for the axial and radial directions, respectively. Eight pressure transducers were used in each test to measure the reflected overpressures on confined chamber walls at key locations. A high speed camera was used to record footage of each blast event. The test results indicated that UFC-3-340-02 (Unified Facilities Criteria, 2008) gives a significantly lower prediction for the axially oriented cylindrical charge, and also underestimates the radially oriented cylinder. Another purpose of the blast program was to develop an experimental data set which would validate the AUTODYN model. This would enable the validated AUTODYN model to be used with confidence to generate the overpressure and impulse distribution on a structural element for varying parameters such as the charge shape and charge orientations. Based on the simulated results a new blast model for cylindrical charges has been proposed by considering blast loading on the same level as the charge across the longitudinal direction.     

Impact of climatic and soil conditions on environmental fate of atrazine used under plantation forestry in Australia

We studied the leaching and dissipation of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3, 5-s-triazine) and its two principal metabolites (desethylatrazine and desisopropylatrazine) for more than two years through soil profiles at five forestry sites across Australia (representing subtropical, temperate and Mediterranean climatic conditions with rainfall ranging from 780 to 1536 mm yr^?1). Following atrazine applications at local label rates, soil cores were collected at regular intervals (up to depths of 90–150 cm), and the residues of the three compounds in soil were analysed in composite samples using liquid chromatography. Bromide was applied simultaneously with atrazine to follow the movement of the soil water. While bromide ion rapidly leached through the entire profile, in most cases the bulk of atrazine, desethylatrazine and desisopropylatrazine remained in the top 45 cm of the soil profile. However, a small fraction of residue moved deeper into the soil profile and at a subtropical site (Toolara) trace levels (ng L^?1) of atrazine and one of its metabolites (DEA) were detected in perched groundwater located at a depth of 1.8 m. Data on the total residues of atrazine in soil profiles from all sites except the Tasmanian site fitted a first-order decay model. The half-life of atrazine in surface soils at the subtropical sites (Toolara and Imbil) ranged from 11 to 21 days. Four separate applications of atrazine at Toolara resulted in a narrow range of half-lives (16 ± 3.6 days), confirming relatively rapid dissipation of atrazine under subtropical conditions (Queensland). In contrast, a prominent biphasic pattern of initial rapid loss followed by very slow phase of degradation of atrazine was observed under the colder temperate climate of Highclere (Tasmania). The data showed that while its 50% (DT₅₀) loss occurred relatively rapidly (36 days), more than 10% of herbicide residue was still detectable in the profile even a year after application (DT₉₀ = 375 days). The rate of dissipation of atrazine at warm subtropical Queensland sites (Imbil and Toolara) was 2–3 times faster than sites located in colder climate of Tasmania. The marked contrast in DT₅₀ values between subtropical and temperate sites suggest that climatic conditions (soil temperature) is one of the key factors affecting atrazine dissipation. At the Tasmanian site, the combination of leaching of the herbicide in subsoil and slower microbial activity at cooler temperatures would have caused a longer persistence of atrazine.     

Percutaneous Exposure Incidents Among Australian Hospital Staff

We investigated all reported percutaneous exposure incidents (PEI) among staff from a large Australian hospital in the 3-year period, 2001-2003. There were a total of 373 PEI, of which 38.9% were needlestick injuries, 32.7% were cutaneous exposures and 28.4% sharps-related injuries. Nurses were the most commonly affected staff members, accounting for 63.5% of the total, followed by doctors (18.8%) and other staff ( 17.7%). Needlestick injuries were responsible for the majority of nurses’ PEI (44.7%). Sharps injuries constituted the major category for doctors (44.3%). Most needlestick injuries (67.6%) were caused by hollow-bore needles, while the majority of cutaneous exposures involved blood or serum (55.8%). Most sharps injures were caused by unknown devices (35.9%) or suture needles (34.9%). Overall, our investigation suggests that PEI is a considerable burden for health care workers in Australia. Further research is now required to determine the relationships, if any, between workers who suffer PEI and those who do not.     

A Validation Study of a Rapid Field-Based Rating System for Discriminating Among Flow Permanence Classes of Headwater Streams in South Carolina

Rapid field-based protocols for classifying flow permanence of headwater streams are needed to inform timely regulatory decisions. Such an existing method was developed for and has been used in North Carolina since 1998. The method uses ordinal scoring of 26 geomorphology, hydrology, and biology attributes of streams. The attribute scores are summed and compared to threshold scores to assign a flow permanence class. Our study objective was to evaluate the method’s ability to classify the flow permanence of forested stream reaches from Piedmont and Southeastern Plains ecoregions in South Carolina. Ephemeral reaches scored significantly lower than intermittent and perennial reaches, but scores from intermittent and perennial reaches did not differ. Scores collected in the dry and wet seasons were strongly correlated, indicating that the method was seasonally stable. Scores had positive nonlinear relationships with the maximum recorded wet duration and the proportion of the record that reaches were wet, but were not related to drying frequency. Scores of the presence of baseflow in the dry season were more important in flow permanence classification than those from the wet season. Other important attributes and parameters in discriminating flow classes were macrobenthos, rooted upland plants, bankfull width, drainage area, and ecoregion. Although the North Carolina method did not consistently differentiate intermittent from perennial reaches, the indicator-based approach is a strong foundation from which to build a protocol for South Carolina. Adding measures like bankfull width and drainage area, weighting by ecoregion, or shifting thresholds may be warranted modifications for South Carolina.     

Development of an Ecologic Marine Classification in the New Zealand Region

We describe here the development of an ecosystem classification designed to underpin the conservation management of marine environments in the New Zealand region. The classification was defined using multivariate classification using explicit environmental layers chosen for their role in driving spatial variation in biologic patterns: depth, mean annual solar radiation, winter sea surface temperature, annual amplitude of sea surface temperature, spatial gradient of sea surface temperature, summer sea surface temperature anomaly, mean wave-induced orbital velocity at the seabed, tidal current velocity, and seabed slope. All variables were derived as gridded data layers at a resolution of 1 km. Variables were selected by assessing their degree of correlation with biologic distributions using separate data sets for demersal fish, benthic invertebrates, and chlorophyll-a. We developed a tuning procedure based on the Mantel test to refine the classification's discrimination of variation in biologic character. This was achieved by increasing the weighting of variables that play a dominant role and/or by transforming variables where this increased their correlation with biologic differences. We assessed the classification's ability to discriminate biologic variation using analysis of similarity. This indicated that the discrimination of biologic differences generally increased with increasing classification detail and varied for different taxonomic groups. Advantages of using a numeric approach compared with geographic-based (regionalisation) approaches include better representation of spatial patterns of variation and the ability to apply the classification at widely varying levels of detail. We expect this classification to provide a useful framework for a range of management applications, including providing frameworks for environmental monitoring and reporting and identifying representative areas for conservation.     

The leaching characteristics of selenium from coal fly ashes

The leaching characteristics of selenium from several bituminous and subbituminous coal fly ashes under different pH conditions were investigated using batch methods. Results indicated that pH had a significant effect on selenium leaching from bituminous coal ash. The minimum selenium leaching occurred in the pH range between 3 and 4, while the maximum selenium leaching occurred at pH 12. The release of selenium from subbituminous coal ashes was very low for the entire experimental pH range, possibly due to the high content of calcium which can form hydration or precipitation products as a sink for selenium. The adsorption results for different selenium species indicated that Se(VI) was hardly adsorbable on either bituminous coal ashes or subbituminous coal ashes at any pH. However, Se(IV) was highly adsorbed by bituminous coal ashes under acidic pH conditions and was mostly removed by subbituminous coal ashes across the entire pH range. This result suggests that the majority of selenium released from the tested fly ashes was Se(IV). A speciation-based model was developed to simulate the adsorption of Se(IV) on bituminous coal fly ash, and the pH-independent adsorption constants of HSeO3* and SeO3 2* were determined. The modeling approach is useful for understanding and predicting the release process of selenium from fly ash.     

Disseminating near-real-time hazards information and flood maps in the Philippines through Web-GIS

The Philippines being a locus of tropical cyclones, tsunamis, earthquakes and volcanic eruptions, is a hotbed of disasters. These natural hazards inflict loss of lives and costly damage to property. Situated in a region where climate and geophysical tempest is common, the Philippines will inevitably suffer from calamities similar to those experienced recently. With continued development and population growth in hazard prone areas, it is expected that damage to infrastructure and human losses would persist and even rise unless appropriate measures are immediately implemented by government. In 2012, the Philippines launched a responsive program for disaster prevention and mitigation called the Nationwide Operational Assessment of Hazards (Project NOAH), specifically for government warning agencies to be able to provide a 6 hr lead-time warning to vulnerable communities against impending floods and to use advanced technology to enhance current geo-hazard vulnerability maps. To disseminate such critical information to as wide an audience as possible, a Web-GIS using mashups of freely available source codes and application program interface (APIs) was developed and can be found in the URLs http:// noah.dost.gov.ph and http://noah.up.edu.ph/. This Web-GIS tool is now heavily used by local government units in the Philippines in their disaster prevention and mitigation efforts and can be replicated in countries that have a proactive approach to address the impacts of natural hazards but lack sufficient funds.