Male and female developmental differences in chemosensory investigations by African elephants (Loxodonta africana) approaching waterholes

Although communication is vital for members of a social species, the sexes may differ in the type and degree of information sought. In many polygynous societies, males search for reproductively active females and compete intrasexually for access to females with older males often being most successful. In social mammals, females may mature sooner than males and thus at an earlier age behave more like adults. This maturation may include the assessment of potential mates directly or via indicative signals. In this study, we observed the behavior of African elephants (Loxodonta africana) during their approach to waterholes. Waterholes provide an opportunity for elephants to investigate conspecific chemical signals from feces and urine, and each other. We examined the presence of sexual dimorphism in behaviors of the trunk that are indicative of olfactory investigation. We predicted that upon approach to a waterhole, adult males would show greater interest than females in conspecific chemical signals. Females were predicted and observed to exhibit adult-like rates of investigatory behavior at a younger age than males because females mature sooner. Adult males took the longest to reach the waterhole in the last 100 m of approach; they also demonstrated greater investigatory rates to conspecific feces. Each sex showed adult-type investigative behaviors with the trunk before the age of reproduction. Rather than showing a common chronological developmental pattern across sex, the exhibition of investigatory, chemosensory behaviors reflected sex-specific changes in reproductive development, perhaps reflective of the relative strength of intra- and intersexual selection on communication patterns.     

A tribute to Trevor Kletz: What we are doing and why we are doing it

The goal of my tribute to Trevor Kletz is to show a view of his overall influence on many of the elements of process safety: how he helped establish a strong foundation on which we are building our future process safety risk reduction efforts.     

Acid Rain Emission Allowances and Future Capacity Growth in the Electric Utility Industry

While the new source emission offset provision contained in recent acid rain proposals would result in increasing utility costs over time, the demand for emission offsets from new powerplant units should be satisfied even under conditions of high future growth in electrical generating capacity. This is because the amount of emissions from new generating units will be small relative to the quantity of offsets that could be made available in the emission “allowance” market.

Under the President’s July 1989 proposal, most utilities would be able to reduce their emissions well below their allowance levels via fuel switching, the installation of control technology, or the use of other emission reduction techniques, in order to create more “headroom” for the construction of new generating units. Retirements and decreasing utilization of existing power plants over time would liberate other emission allowances for use by new units. Industrial sources could “opt in” to the acid rain program and provide allowances for new generating units as well. A number of provisions in the recently passed Senate and House bills would make still further sources of allowances available to offset emissions from new generating capacity.

Hoarding of allowances by utilities is unlikely to be a problem since allowances would be distributed to at least 88 utilities in 34 states, and many of these utilities would have the ability to cost-effectively free up more allowances through “overcontrol” than they would need to cover their own future growth. Even a relatively small number of utilities in a limited number of states would have the ability to supply all of the allowances needed to cover new capacity growth from those entities that could not otherwise provide their own offsets. At projected prices of up to $800/ton, the incentives for utilities to sell allowances would be considerable. Moreover, if hoarding did begin to occur, the price of allowances would respond by rising to higher levels and the incentives for utilities to sell allowances would become even more compelling, as greater opportunities would develop for reducing costs (and electricity rates).     

summary of the California aerosol characterization experiment

This report gives a brief summary of the experimental plan and the early results of field observations from the California Aerosol Characterization Experiment (ACHEX). The objectives of the program center on questions of the sources and evolution of aerosols in urban air, as they are superimposed on a natural background, particularly as they relate to visibilitydegradation. The project initially nvolved the use of an elaborately instrumented mobile laboratory combined with a fixed station in San Jose, in Pasadena, and in Riverside, and later incorporated several satellite monitoring stations in the Los Angeles Basin. Intensive field observationswere taken from July 1972 to November 1972 in several urban and nonurban locations between the San Francisco Bay area and the South Coast Basin, covering the Los Angeles area. In a second phase of the ACHEX, aerosols accompanying photochemical smog were studied intensively in the Los Angeles Basin during the period between July and October of 1973. The observations cover a wide variety of parameters including physical and chemical properties of aerosols, pollutant gas concentrations, and meteorological variables. The initial results show the great importance of sulfate, nitrate, noncarbonate carbon, and liquid water to the mass concentration of airborne particles and their relation to reduction in visibility. The anthropogenic contribution to atmospheric aerosols is consistently found to be allocated primarily to the submicron or fine particle size range.     

Using structural equation modeling to investigate relationships among ecological variables

Structural equation modeling is an advanced multivariate statistical process with which a researcher can construct theoretical concepts, test their measurement reliability, hypothesize and test a theory about their relationships, take into account measurement errors, and consider both direct and indirect effects of variables on one another. Latent variables are theoretical concepts that unite phenomena under a single term, e.g., ecosystem health, environmental condition, and pollution (Bollen, 1989). Latent variables are not measured directly but can be expressed in terms of one or more directly measurable variables called indicators. For some researchers, defining, constructing, and examining the validity of latent variables may be the end task of itself. For others, testing hypothesized relationships of latent variables may be of interest. We analyzed the correlation matrix of eleven environmental variables from the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program for Estuaries (EMAP-E) using methods of structural equation modeling. We hypothesized and tested a conceptual model to characterize the interdependencies between four latent variables-sediment contamination, natural variability, biodiversity, and growth potential. In particular, we were interested in measuring the direct, indirect, and total effects of sediment contamination and natural variability on biodiversity and growth potential. The model fit the data well and accounted for 81% of the variability in biodiversity and 69% of the variability in growth potential. It revealed a positive total effect of natural variability on growth potential that otherwise would have been judged negative had we not considered indirect effects. That is, natural variability had a negative direct effect on growth potential of magnitude –0.3251 and a positive indirect effect mediated through biodiversity of magnitude 0.4509, yielding a net positive total effect of 0.1258. Natural variability had a positive direct effect on biodiversity of magnitude 0.5347 and a negative indirect effect mediated through growth potential of magnitude –0.1105 yielding a positive total effects of magnitude 0.4242. Sediment contamination had a negative direct effect on biodiversity of magnitude –0.1956 and a negative indirect effect on growth potential via biodiversity of magnitude –0.067. Biodiversity had a positive effect on growth potential of magnitude 0.8432, and growth potential had a positive effect on biodiversity of magnitude 0.3398. The correlation between biodiversity and growth potential was estimated at 0.7658 and that between sediment contamination and natural variability at –0.3769.     

Evaluating Change in Rangeland Condition using Multitemporal AVHRR Data and Geographic Information System Analysis

Coarse-scale, multitemporal satellite image data were evaluated as a tool for detecting variation in vegetation productivity, as a potential indicator of change in rangeland condition in the western U.S. The conterminous U.S. Advanced Very High Resolution Radiometer (AVHRR) biweekly composite data set was employed using the six-year time series 1989–1994. Normalized Difference Vegetation Index (NDVI) image bands for the state of New Mexico were imported into a Geographic Information System (GIS) for analysis with other spatial data sets. Averaged NDVI was calculated for each year, and a series of regression analyses were performed using one year as the baseline. Residuals from the regression line indicated 14 significant areas of NDVI change: two with lower NDVI, and 11 with higher NDVI. Rangeland management changes, cross-country military training activities, and increases in irrigated cropland were among the identified causes of change.     

Source apportionment of particulate matter (PM2.5) in an urban area using dispersion,receptor and inverse modelling

Air pollution emission inventories are the basis for air quality assessment and management strategies. The quality of the inventories is of great importance since these data are essential for air pollution impact assessments using dispersion models. In this study, the quality of the emission inventory for fine particulates (PM_2.5) is assessed: first, using the calculated source contributions from a receptor model; second, using source apportionment from a dispersion model; and third, by applying a simple inverse modelling technique which utilises multiple linear regression of the dispersion model source contributions together with the observed PM_2.5 concentrations. For the receptor modelling the chemical composition of PM_2.5 filter samples from a measurement campaign performed between January 2004 and April 2005 are analysed. Positive matrix factorisation is applied as the receptor model to detect and quantify the various source contributions. For the same observational period and site, dispersion model calculations using the Air Quality Management system, AirQUIS, are performed. The results identify significant differences between the dispersion and receptor model source apportionment, particularly for wood burning and traffic induced suspension. For wood burning the receptor model calculations are lower, by a factor of 0.54, but for the traffic induced suspension they are higher, by a factor of 7.1. Inverse modelling, based on regression of the dispersion model source contributions and the PM_2.5 concentrations, indicates similar discrepancies in the emissions inventory. In order to assess if the differences found at the one site are generally applicable throughout Oslo, the individual source category emissions are rescaled according to the receptor modelling results. These adjusted PM_2.5 concentrations are compared with measurements at four independent stations to evaluate the updated inventory. Statistical analysis shows improvement in the estimated concentrations for PM_2.5 at all sites. Similarly, inverse modelling is applied at these independent sites and this confirms the validity of the receptor model results.     

Chromosomal genes conferring tolerance to heavy metal (Ag) toxicity

Bacterial strains were isolated from sediment samples from the Thames River. Successive transfer growth of the various strains on nutrient agar containing increasing concentrations of AgNO₃ revealed that three of the bacterial isolates were found to be capable of tolerating high concentrations of AgNO₃ ranging from 20 to 80 mM on a solid medium and up to 10 mM AgNO₃ in liquid medium. Molecular characterization and identification based on 16S rDNA gene sequencing of three strains of bacteria that are tolerant to silver nitrate showed that the major tolerant strains include the superbug, Shewanella oneidensis, Pseudomonas sp. and Bacillus sp. Protein extraction and two-dimensional (2D) sodium dodecyl sulfate SDS-polyacrylamide gel electrophoresis (PAGE) of the protein extracts in bacteria exposed to very high concentrations of AgNO₃ revealed a general reduction in the number of expressed proteins, although two protein spots were conspicuously over expressed in the exposed bacteria compared to control. The N-terminal amino acid sequence analysis of the protein spots identified the major up-regulated proteins as the outer membrane protein To1C (45.2 kDa) and the structural protein of the flagellar filament, flagellin (28.34 kDa), encoded for by the to1C and fliC genes, respectively. The roles of these genes in a number of multi-drug resistant pathogen and potentials for biotechnological applications in toxic metal control for treatment of contaminated ecosystems and biomining were discussed.     

The network imaginary: coherence and creativity within a multiscalar collaborative effort to reform US fire management

In response to the ongoing crisis in fire management, the US Fire Learning Network (FLN) engages partners in collaborative, landscape-scale ecological fire restoration. The paper contends that the FLN employs technologies, planning guidelines and media to articulate an FLN imaginary that co-ordinates independent efforts to engage in ecological fire restoration work without need of either hierarchal authority or collective social capital. This imaginary may allow the FLN to draw on the creativity and adaptive innovation of collaboration to reform fire management institutions and fire-adapted ecosystems.