Fate of turbid glacial inflows in a hydroelectric reservoir

Environmental Fluid Mechanics - Turbidity from glacial meltwater limits light penetration with potential ecological consequences. Using profiles of temperature, conductivity, and turbidity, we...     

Metals in the indoor environment

There is a growing recognition that individual exposures to a broad spectrum of metal, inorganic and organic pollutants exceed those from ambient and in some cases from the vicinity of industry environments. The agents often found in indoor environments are mostly known to be hazardous in high concentrations, but the lower limit of their dose response relationships are poorly defined.

The major sources of metals in indoor environments are cigarette smoke (mainstream and side stream), fuel combustion, house dust and consumer products with arsenic, cadmium, lead and nickel being of primary toxicological potential (i.e. carcinogenic, genotoxic and reproductive development). Aspects of levels and duration of human exposure to these elements in relation to existing body burdens and subsequent bioavailability and interactions are generally poorly known from inhalation sources.

Although the magnitude of indoor health hazards to metallic constituents is not now known, mounting evidence suggests that both identification of agents and the measurement of indoor exposures are critical for a more realistic assessment of the effect of this aspect of air pollution on human health.     

Levels of community participation and satisfaction with decentralized wildlife management in Idodi-Pawaga Wildlife Management Area,Tanzania

Participatory approaches to conservation are viewed as a plausible alternative to the old ‘fortress conservation’ approach. The design and implementation of these approaches in developing countries have tended to embrace community participation through decentralized governance mechanisms in the past three decades. However, sustainable conservation approaches that maintain community livelihoods while conserving biodiversity are challenged with meeting both objectives. In addressing this challenge, little attention has been given to an empirical analysis of community’s satisfaction levels on how they participated in the design and implementation of this approach. In this article, we use a mixed method approach using both quantitative and qualitative data to examine levels of satisfaction and participation of local communities in the Idodi-Pawaga Wildlife Management Area (WMA), south-western Tanzania. We find that social economic factors (e.g. age, household size, gender, number of years living in the same location and participation/non-participation) influence, in different ways, the satisfaction levels of community’s participation towards the WMA creation. Due to inadequate participation, we find that the WMA design and implementation process failed from the beginning to actively involve the local communities and this has resulted in the near absence of the promised economic benefits from wildlife conservation. We suggest that participation should go beyond the simple information sharing to actively engage the local communities in key planning activities from the beginning of any WMA programme. It is also important to take into consideration their levels of satisfaction with the process of decision-making if meaningful decentralized governance is to be achieved.     

Photosynthetic resource-use efficiency and demographic variability in desert winter annual plants

We studied a guild of desert winter annual plants that differ in long-term variation in per capita reproductive success (lb, the product of per capita survival from germination to reproduction, l, times per capita reproduction of survivors, b) to relate individual function to population and community dynamics. We hypothesized that variation in lb should be related to species' positions along a trade-off between relative growth rate (RGR) and photosynthetic water-use efficiency (WUE) because lb is a species-specific function of growing-season precipitation. We found that demographically variable species have greater RGR and greater leaf carbon isotope discrimination (Delta, a proxy inversely related to WUE). We examined leaf nitrogen and photosynthetic characteristics and found that, in this system, variation in Delta is a function of photosynthetic demand rather than stomatal regulation of water loss. The physiological characteristics that result in low Delta in some species may confer greater photosynthetic performance during the reliably moist but low temperature periods that immediately follow winter rainfall in the Sonoran Desert or alternatively during cool periods of the day or early growing season. Conversely, while species with high Delta and high RGR exhibit low leaf N, they have high biomass allocation to canopy leaf area display. Such trait associations may allow for greater performance during the infrequent conditions where high soil moisture persists into warmer conditions, resulting in high demographic variance. Alternatively, high variance could arise from specialization to warm periods of the day or season. Population dynamic buffering via stress tolerance (low RGR and Delta) correlates negatively with buffering via seed banks, as predicted by bet-hedging theory. By merging analyses of population dynamics with functional trait relationships, we develop a deeper understanding of the physiological, ecological, and evolutionary mechanisms involved in population and community dynamics.     

The effects of temperature,body size and growth rate on energy losses due to metabolism in early life stages of haddock (<Emphasis Type="Italic">Melanogrammus aeglefinus</Emphasis>)

Rates of routine respiration (R _R, μl O₂ fish⁻¹ h⁻¹) and total ammonia nitrogen excretion (E _R, μg NH₄–N + NH₃–N fish⁻¹ h⁻¹) were measured on larval and juvenile haddock (Melanogrammus aeglefinus) to ascertain how energy losses due to metabolism were influenced by temperature (T), dry body mass (M _D, mg) and specific growth rate (SGR, % per day). R _R and E _R increased with M _D according to y = a  · M _D ^b with b-values of 0.96, 0.98, 1.14, and 0.89, 0.78, 0.74, respectively, at 10, 7, and 4°C, respectively. Multiple regressions explained 98% of the variability in the combined effects of M _D and T on R _R and E _R in larval haddock: R _R = 0.97 · M _D ^0.98  · e^0.092 · T ; E _R = 0.06 · M _D ^0.79  · e^0.092 · T . In young juvenile (24–30 mm standard length) haddock, R _R tended to decline (P = 0.06) and E _R significantly declined (P = 0.02) with increasing SGR. O:N ratios significantly increased with increasing SGR suggesting that N was spared in relatively fast-growing individuals. Our results for young larval and juvenile haddock suggest: (1) nearly isometric scaling of R _R with increasing body size, (2) allometric scaling of E _R with increasing body size, (3) Q ₁₀ values of 2.5 for both R _R and E _R, (4) metabolic differences in substrate utilization between relatively fast- and slow-growing individuals, and (5) that rates of routine energy loss and growth were not positively related. The measurements in this study will provide robust parameter estimates for individual-based models that are currently being utilized to investigate how variability in climatic forcing influences the vital rates of early life stages of haddock. Our results also stress that inter-individual differences in rates of energy loss should not be overlooked as a factor influencing growth variability among individuals.     

Assessing potential risks to wildlife and sportsmen from exposure to dioxin in pulp and paper mill sludge spread on managed woodlands

Potential human and wildlife exposures to TCDD in landspread pulp and paper mill sludge in the State of Maine were evaluated by means of a human health and an ecological risk assessment methodology. The highest historical concentrations of TCDD reported for these sludges do not present a risk to American woodcock, selected as an indicator species for this analysis. Concentrations of TCDD as high as 50 ppt in soil are not likely to produce adverse effects in the embryonic/hatchling stage of the woodcock. This soil concentration of TCDD does not present a significant risk to sportsmen and their families that may consume birds which inhabit these sites.     

Parental risk perceptions of childhood pedestrian road safety: a cross cultural comparison

INTRODUCTION: This cross-sectional community-based randomized telephone survey, aimed to compare the parental risk perceptions on childhood pedestrian road safety among three different major community language speaking groups and the mainstream English speaking Australians in Sydney, Australia. METHOD: This was a community-based telephone survey with subjects randomly selected from the population of specific cultural languages in Sydney. RESULTS: Results indicated that Chinese and Arabic speaking parents or caregivers perceived the road environments as significantly less hazardous for their 4-12 year old children as pedestrians when compared with Vietnamese and English speaking parents. This was true even after adjusting for the age of child, socioeconomic status, and the living environments of respondents. CONCLUSION: The implication of the results was discussed in light of possible application to childhood safety behavior across different cultures. IMPACT TO THE INDUSTRY: The results obtained have highlighted the importance of cultural factors in risk perceptions, and safety behaviors. Cultural differences in risk perceptions should be taken into consideration in the design of safety education programs.     

Effects of basaltic mineral fines on composting

A by-product of the construction aggregate industry is fines or dust that contain trace elements such as zinc and copper and significant amounts of iron, aluminum, silica and potassium. Beneficial uses for these materials have been proposed such as replenishing depleted soils and amendment in mixtures of organic byproducts prior to composting. To evaluate the beneficial uses in composting, outdoor bin studies were conducted using a beef cattle manure, straw and wood chip mixture amended with and without basaltic mineral fines. Temperature differences in composting mixtures of equal volumes, equal moisture and relatively equal material content are considered an indication of differing biological activities [Haug, Compost Engineering Principles and Practice. Ann Arbor Science, Ann Arbor, MI. (1980)]. Temperatures were lower in the mineral fine-treated manure mixture initially. After turning the piles at six weeks, temperatures tended to be higher in the mineral fine amended mixture. Overall, temperatures were not significantly different suggesting that mineral fines amendment does not significantly increase temperature and activity in composting mixtures.     

Use of stream chemistry for monitoring acidic deposition effects in the Adirondack region of New York

Acid-neutralizing capacity (ANC) and pH were measured weekly from October 1991 through September 2001 in three streams in the western Adirondack Mountain region of New York to identify trends in stream chemistry that might be related to changes in acidic deposition. A decreasing trend in atmospheric deposition of SO4/2- was observed within the region over the 10-yr period, although most of the decrease occurred between 1991 and 1995. Both ANC and pH were inversely related to flow in all streams; therefore, a trend analysis was conducted on (i) the measured values of ANC and pH and (ii) the residuals of the concentration-discharge relations. In Buck Creek, ANC increased significantly (p < 0.05) over the 10 yr, but the residuals of ANC showed no trend (p > 0.10). In Bald Mountain Brook, ANC and residuals of ANC increased significantly (p < 0.01), although the trend was diatonic-a distinct decrease from 1991 to 1996 was followed by a distinct increase from 1996 to 2001. In Fly Pond outlet, ANC and residuals of ANC increased over the study period (p < 0.01), although the trend of the residuals resulted largely from an abrupt increase in 1997. In general, the trends observed in the three streams are similar to results presented for Adirondack lakes in a previous study, and are consistent with the declining trend in atmospheric deposition for this region, although the observed trends in ANC and pH in streams could not be directly attributed to the trends in acidic deposition.     

Biobased Epoxy/Layered Silicate Nanocomposites: Thermophysical Properties and Fracture Behavior Evaluation

The biobased epoxy containing epoxidized linseed oil (ELO) and its clay nanocomposites were processed with an anhydride curing agent. The certain amount of diglycidyl ether of bisphenol F (DGEBF) was replaced by ELO. The selection of the DGEBF, ELO, an anhydride curing agent, and organo-montmorillonite clay resulted in an excellent combination, to provide new biobased epoxy/clay nanocomposites showing high elastic modulus, high glass transition temperature, and high fracture toughness with larger amount of ELO. Izod impact strength was almost constant while changing the amount of ELO. This is a promising result for future applications in different engineering industries.