Human exposure to 2,4-D following controlled activities on recently sprayed turf.

Total body dose of 2,4-D was determined in 10 volunteers following exposure to sprayed turf 1 hour following application and in 10 volunteers exposed 24 hours following application. Each group of 10 volunteers was divided in half and five wore long pants, a short-sleeved shirt, socks and closed footwear. The other five wore shorts and a short-sleeved shirt and were barefoot. All volunteers were exposed to a 2 by 15 m area of turf for 1 hour during which they alternated between walking and sitting or lying on the turf surface for intervals of 5 minutes. Dislodgeable residues of 2,4-D taken during the exposure sessions showed a rapid decline from 1 hour following application (8%) to 24 hours following application (1%). No detectable residues were found in 4-day urine samples supplied by volunteers except for 3 people who were barefoot and wearing shorts and contacted the turf 1 hour following 2,4-D application. The highest dose was measured in a volunteer who removed his shirt for 30 minutes of the exposure session (426 micrograms). Exposure levels of the other two volunteers who wore the prescribed clothing were lower (153 and 103 micrograms). No detectable residues were found in urine samples supplied by volunteers exposed to sprayed turf 24 hours following application. These results indicate that at the doses measured, exposure to sprayed turf should present little risk in humans. However, people can reduce exposure to non-detectable levels by remaining off treated turf for a period of 24 hours or until after rainfall or irrigation so that dislodgeable residues and therefore potential exposure are essentially zero.     

Mechanical Property and Biodegradability of Cast Films Prepared from Blends of Oppositely Charged Biopolymers

Biodegradable cast films of about 50 m thickness were fabricated by blending oppositely charged biopolymers such as anionic starch–chitosan, and cationic starch–pectin. The tensile strength and elongation at break (%) of films were evaluated as well as their capacity to degrade in compost. Films recovered from soil every 48 h showed consistent degradation (weight loss), diminution of the polymers characteristic peak absorbance in the carbohydrate fingerprint region of the FTIR, and changes in the surface morphology via scanning electron microscopy (SEM). Anionic starch–chitosan films had much superior tensile strength and elongation compared to cationic starch–pectin, suggesting that the ionic bonds formed between anionic-starch and positively charged groups in chitosan polymer were much more stable and stronger. Initially, both films lost about 36% weight within 96 h, which also correlated well with the loss in the characteristic absorption peaks in the region of the infrared spectrum typical of biopolymers. The total mineralization of films by microorganisms in compost soil was also measured using respirometric techniques. Though the rate of mineralization differed for two formulations, total mineralization (extent) for both films were achieved within 45 days.     

Revegetation of an abandoned uranium millsite on the Colorado Plateau, Arizona

We attempted to restore native plants on disturbed sites at a former uranium mill on the Colorado Plateau near Tuba City, AZ. Four-wing saltbush [Atriplex canescens (Pursh) Nutt.] was successfully established in compacted caliche soil and in unconsolidated dune soil when transplants were irrigated through the first summer with 20 L/plant/wk. The caliche soil was ripped before planting to improve water-holding capacity. The diploid saltbush variety, angustifolia, had higher survival and growth than the common tetraploid variety, occidentalis, especially on dune soil. The angustifolia variety grew to 0.3 to 0.4 m3 per plant over 3 yr even though irrigation was provided only during the establishment year. By contrast, direct seeding of a variety of native forbs, grasses, and shrubs yielded poor results, despite supplemental irrigation throughout the first summer. In this arid environment (precipitation = 100 to 200 mm/yr), the most effective revegetation strategy is to establish keystone native shrubs, such as four-wing saltbush, using transplants and irrigation during the establishment year, rather than attempting to establish a diverse plant community all at once.     

Indoor air exposure to coal and wood combustion emissions associated with a high lung cancer rate in Xuan Wei, China

Residents of Xuan Wei County in China have unusually high lung cancer mortality that cannot be attributed to tobacco use or occupational exposure. They are exposed to smoke from unvented, open pit coal or wood fires (often used for cooking and heating). The variation in lung cancer rates among communes within the county suggests that indoor combustion of smoky coal may be the prime determinant of lung cancer. To characterize the air in Xuan Wei homes, samples of air particles and semivolatile organic compounds were collected from homes located in two communes; one commune has a high rate of lung cancer, and the other has a low rate. Samples collected in the commune where the lung cancer rate is high and where smoky coal is the predominant fuel contained high concentrations of small particles with high organic content; organic extracts of these samples were mutagenic. Samples from homes in the wood-burning commune, which has a low rate of lung cancer, consisted mostly of larger particles of lower organic content and mutagenicity. The smoky coal sample was a mouse skin carcinogen and was a more potent initiator of skin tumors in comparison to the wood or smokeless coal sample.     

Detritus as food for estuarine copepods

A variety of detrital foods derived from marsh plants were fed to the copepods Eurycemora affinis and Scottolana canadensis. The copepods did not survive well or produce eggs when feeding on detritus with smaller amounts of microbiota, but did well when a rich and abundant microbiota was present. Ciliated protozoans appear to be particularly important in the transfer of detrital energy to copepods.Contribution No. 703, Center for Environmental and Estuarine Studies, University of Maryland.     

“If you treat me right,I reciprocate”: examining the role of exchange in organizational survey response

Survey nonresponse can pose a major threat to the generalizability of organizational survey findings. This paper examines whether organizational members' evaluations of their organizational experiences affect survey response to organizationally sponsored surveys. In particular, we hypothesized that perceived organizational support, social exchange, procedural justice and an individual's inclination to feel exploited in social relationships predicted organizational members' compliance with organizations' requests for survey completion. A longitudinal field experiment conducted in collaboration with the Office of Institutional Research at a large university (sample: n = 622 university students) supported the hypotheses. Organizational members who consciously decided to not participate in organizational surveys perceived their organization as less procedurally just and less supportive. They also reported negative perceptions of their social exchange relationship with their organization, and were more inclined to feel exploited in relationships. Hence, an exchange‐oriented theoretical framework grounded in organizational citizenship behavior theory seems appropriate for the study of survey nonresponse. Implications for survey practice include that survey‐based findings are unlikely to generalize to specific groups of nonrespondents, and that techniques commonly used to increase response rates may not be effective in reaching these groups of nonrespondents. Copyright © 2006 John Wiley & Sons, Ltd.     

Hydrogen production from biomass

The ‘hydrogen economy’ has received considerable attention in academic, industrial and political contexts. There are opportunities for vast reductions in greenhouse gas emissions, increased energy security and greater overall efficiency. However, if hydrogen is to become a fundamental energy source for electrical power generation, as well as a transportation fuel, novel generation pathways will be necessary to meet the increase in demand. A promising means for generating hydrogen is the thermochemical conversion of biomass to a synthesis gas, composed of a mixture of hydrogen, carbon monoxide, carbon dioxide and methane. In order to manipulate the composition and maximise the hydrogen output, a calcium-based carbon dioxide sorbent can be utilised in situ. The removal of carbon dioxide alters the reaction chemistry to preferentially produce hydrogen. In this work we report on the characterisation of a likely Ca-based carbon dioxide sorbent and demonstrate the merits of hydrogen production from biomass, with in situ carbon dioxide capture, on the basis of a thermodynamic study. Using this model we show that hydrogen output from biomass gasification can be increased from 40%-vol to 80%-vol (dry basis) when a carbon dioxide sorbent is used.     

The moderating effects of political skill on the perceived politics–outcome relationships

Previous research has established that perceptions of organizational politics are associated with negative organizational outcomes. However, this may not hold true for all individuals. We offer subordinate and supervisor political skill, the ability to understand interactions at work and to use that understanding to effectively influence others, as possible moderators. Specifically, this study investigates the impact of both employees' self‐rated political skill and their managers' political skill on job satisfaction, job performance, and manager‐rated commitment. We examined these relationships in an organizational sample of 106 matched dyadic pairs and found mixed support for the joint moderating effect of self and manager political skill on the politics perceptions‐outcome relationships. Strengths, limitations, and directions for future research are discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

The influence of estuarine water quality on cover of barnacles and Enteromorpha spp.

The influence of ambient water quality on the settlement of barnacles and the green alga Enteromorpha spp. to an artificial substratum in the estuaries of Sydney, Australia, was investigated to test the efficacy of both groups of organisms as indicators of changes in water quality due to urban stormwater runoff and/or sewage overflows. Wooden settlement panels were immersed for 4 months on 17 occasions between 1996 and 2005 at 11 locations known to vary in water-quality parameters (conductivity, total uncombined ammonia, oxidised nitrogen, total nitrogen, filterable phosphorus, total phosphorus, faecal coliforms and chlorophyll-a) and ambient meteorological conditions (total rainfall, maximum rainfall). Water-quality data were collected during the time that the settlement panels were deployed. Cover of barnacles was highly variable among locations (range 1.2?C55.2%). Hierarchical partitioning found that chlorophyll-a, total phosphorus and total nitrogen had significant independent positive effects on barnacle cover. Together, these variables explained 26% of the variation in barnacle cover. Mean cover of Enteromorpha spp., however, did not vary significantly among locations suggesting that other potentially more important factors are influencing its settlement and growth. The results of this study suggest that barnacle cover is likely to be a useful indicator of some components of water quality.