Effect of formulation on the behavior of 1,3-dichloropropene in soil

The fumigant 1,3-dichloropropene (1,3-D) has been identified as a partial replacement for methyl bromide (CH3Br) in soil fumigation. 1,3-Dichloropropene is formulated for soil fumigation as Telone II (Dow AgroSciences, Indianapolis, IN) for shank application and as an emulsifiable concentrate (EC) (Telone EC or InLine; Dow AgroSciences) for drip application. This study investigated the effect of formulation on the phase partitioning, transformation rate, and volatilization of 1,3-D isomers. Air-water partitioning coefficients (K(H)) were slightly higher for Telone II than for Telone EC, presumably due to the higher apparent water solubility of the EC formulation. Sorption of 1,3-D isomers in two soils was not affected by formulation. Formulation had no significant effect on the rate of 1,3-D transformation in water or soil. In general, differences in the rate of 1,3-D transformation and phase partitioning due to formulation as Telone II or Telone EC were very small. Thus, the effect of formulation on 1,3-D fate may be ignored in transformation and phase partition of 1,3-D in water and soil. Packed soil columns without plastic tarp indicated that with relatively shallow subsurface (10 cm) drip application of Telone EC, emission of 1,3-D isomers was more rapid and produced greater maximum instantaneous flux than deeper (30 cm) shank injection of Telone II. Both application methods resulted in the same cumulative emissions for both isomers, 45% for (E)-1,3-D and approximately 50% for (Z)-1,3-D. These results suggest that for drip application of fumigants to be effective in reducing emissions, the fumigant must be applied at sufficient depths to prevent rapid volatilization from the soil surface if the water application rate does not sufficiently restrict vapor diffusion.     

Fear of terror and increased job burnout over time: Examining the mediating role of insomnia and the moderating role of work support

While the prevalence of terrorism has increased substantially, there is a paucity of research on the effects of terrorism on employee behavior at work. Building on conservation of resources (COR) theory, and its extension, the conservation of social resources theory, we close gaps in the literature by investigating the effect of fear of terror on increased job burnout over time, the mediating effect of insomnia, and the moderating effect of supervisor and co‐worker support on these relationships. This longitudinal study followed a large sample of Israeli employees (n = 670) across three time measurements over 7 years, in a time period characterized by a high number of terror attacks. The results showed fear of terror to be related to elevated job burnout over time, even during a period in which terror attacks were reduced substantially. Further, insomnia mediated the relationship between fear of terror and increased burnout, while co‐worker support, but not supervisor support, moderated the relationships between fear of terror and increased insomnia and between increased insomnia and increased burnout. The results further support the notion of loss cycles in COR theory, as well as the importance of social resources, which are the cornerstones of conservation of social resources theory. Copyright © 2014 John Wiley & Sons, Ltd.     

Not all is fair in love and work: coworkers' preferences for and responses to managerial interventions regarding workplace romances

This article proposes a model of coworkers' preferences for and responses to managerial interventions regarding workplace romances (WRs). Specifically, the model examines the antecedents of coworkers' preferences for managerial intervention in WRs and the consequences of whether their preferred intervention is congruent with the actual managerial intervention. According to the model, coworkers' preferences for managerial intervention are influenced by their perceptions of the impact of the WR on the work environment, including perceptions of whether it represents a conflict of interest for the two participants and whether it disrupts the functioning of the work group. These perceptions are affected by factors pertaining to the romance itself, the coworkers themselves, and the organizational context in which the romance occurs. Next, consistent with the organizational justice literature, we propose that coworkers will evaluate the distributive and procedural justice of the managerial intervention according to (a) the congruence between the severity of their preferred managerial action and the severity of the actual managerial action and (b) the congruence between their beliefs about a just process for managerial decision making about WRs and the actual process. Finally, we propose that coworkers who perceive the managerial intervention process and outcomes as unjust will exhibit negative work‐related attitudes (e.g., decreased job satisfaction and organizational commitment) and behavior (e.g., decreased productivity and organizational citizenship behaviors). Implications of the model for future research and organizational practice are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Project XL: cheaper,cleaner, and smarter ways to protect the environment

Are you interested in making the job of complying with federal environmental requirements cheaper and smarter for your business? The U.S. Environmental Protection Agency is committed to helping business and other sectors make more sense of environmental requirements through a number of innovative programs, one of the most far‐reaching being Project XL. © 2000 John Wiley & Sons, Inc.     

Diversity-invasibility across an experimental disturbance gradient in Appalachian Forests

Research examining the relationship between community diversity and invasions by nonnative species has raised new questions about the theory and management of biological invasions. Ecological theory predicts, and small-scale experiments confirm, lower levels of nonnative species invasion into species-rich compared to species-poor communities, but observational studies across a wider range of scales often report positive relationships between native and nonnative species richness. This paradox has been attributed to the scale dependency of diversity-invasibility relationships and to differences between experimental and observational studies. Disturbance is widely recognized as an important factor determining invasibility of communities, but few studies have investigated the relative and interactive roles of diversity and disturbance on nonnative species invasion. Here, we report how the relationship between native and nonnative plant species richness responded to an experimentally applied disturbance gradient (from no disturbance up to clearcut) in oak-dominated forests. We consider whether results are consistent with various explanations of diversity-invasibility relationships including biotic resistance, resource availability, and the potential effects of scale (1 m2 to 2 ha). We found no correlation between native and nonnative species richness before disturbance except at the largest spatial scale, but a positive relationship after disturbance across scales and levels of disturbance. Post-disturbance richness of both native and nonnative species was positively correlated with disturbance intensity and with variability of residual basal area of trees. These results suggest that more nonnative plants may invade species-rich communities compared to species-poor communities following disturbance.     

A 700-year paleoecological record of boreal ecosystem responses to climatic variation from Alaska

Recent observations and model simulations have highlighted the sensitivity of the forest-tundra ecotone to climatic forcing. In contrast, paleoecological studies have not provided evidence of tree-line fluctuations in response to Holocene climatic changes in Alaska, suggesting that the forest-tundra boundary in certain areas may be relatively stable at multicentennial to millennial time scales. We conducted a multiproxy study of sediment cores from an Alaskan lake near the altitudinal limits of key boreal-forest species. Paleoecological data were compared with independent climatic reconstructions to assess ecosystem responses of the forest tundra boundary to Little Ice Age (LIA) climatic fluctuations. Pollen, diatom, charcoal, macrofossil, and magnetic analyses provide the first continuous record of vegetation fire-climate interactions at decadal to centennial time scales during the past 700 years from southern Alaska. Boreal-forest diebacks characterized by declines of Picea mariana, P. glauca, and tree Betula occurred during the LIA (AD 1500-1800), whereas shrubs (Alnus viridis, Betula glandulosa/nana) and herbaceous taxa (Epilobium, Aconitum) expanded. Marked increases in charcoal abundance and changes in magnetic properties suggest increases in fire importance and soil erosion during the same period. In addition, the conspicuous reduction or disappearance of certain aquatic (e.g., Isoetes, Nuphar, Pediastrum) and wetland (Sphagnum) plants and major shifts in diatom assemblages suggest pronounced lake-level fluctuations and rapid ecosystem reorganization in response to LIA climatic deterioration. Our results imply that temperature shifts of 1-2 degrees C, when accompanied by major changes in moisture balance, can greatly alter high-altitudinal terrestrial, wetland, and aquatic ecosystems, including conversion between boreal-forest tree line and tundra. The climatic and ecosystem variations in our study area appear to be coherent with changes in solar irradiance, suggesting that changes in solar activity contributed to the environmental instability of the past 700 years.     

A quantitative comparison of the commonly used methods for extracting carotenoids from avian plasma

Interest in animal carotenoids, especially in birds, has exploded in recent years, and so too have the methods employed to investigate the nature and function of these pigments. Perhaps the most easily and commonly performed procedure in this work has been the determination of carotenoid concentration from avian plasma. Over the past 20 years of research on avian carotenoids, numerous methods have been used to extract carotenoids from bird plasma, all of which have differed in several important parameters (e.g., number and types of solvents used, degree of mixing/centrifugation). However, to date, no study has systematically compared these methods to determine if any of them are more effective than others for recovering any or all types of carotenoids present. We undertook such an investigation on plasma samples from two bird species (house finch, Carpodacus mexicanus, and mallard, Anas platyrhynchos) using five of the most commonly employed methods for extracting carotenoids from avian plasma: (1) acetone-only, (2) methanol-only, (3) ethanol-only, (4) ethanol + hexane, and (5) ethanol + tert butyl methyl ether. We also manipulated the amount of time that extracts were centrifuged, which has varied tremendously in previous studies, to evaluate its importance on carotenoid recovery. We found that all methods equally recovered the polar xanthophylls (lutein and zeaxanthin), but that the methanol-only procedure poorly recovered non-polar carotenoids (less β-carotene in both species and less β-cryptoxanthin in house finches) compared to the other methods. These results suggest that the data accumulated to date on xanthophyll plasma carotenoids in birds should be comparable across studies and species despite the different chemical extraction methods used. However, care should be taken to use relatively strong organic solvents for fully recovering non-polar carotenoids. We also found no effect of centrifugation duration (1 vs. 10 min at 10,000 rpm) on carotenoid recoveries, demonstrating that researchers can save considerable time by centrifuging for a much shorter time period than is typically used.     

Flightlessness and the energetic cost of wing molt in a large sea duck

Although the replacement of feathers apparently represents the major event of somatic production in the annual cycle of wild birds, knowledge about the energetics of molt has always been hampered by logistical and technical difficulties, which are exacerbated by the fact that birds are able to compensate behaviorally to buffer any variation in energy demand. During wing molt, sea ducks (Mergini) and other diving birds lose all of their wing feathers at once, leading to a period of temporary flightlessness of variable duration, a condition that considerably restricts their movements and increases the probability of predation. In the present study, we present the first results aimed at quantifying the duration of flightlessness, energy expenditure, and foraging effort during molt of a wing-propelled diving bird, the Common Eider (Somateria mollissima). Data loggers were implanted in the body cavity of 13 females to record heart rate and hydrostatic pressure (depth) every two seconds for a period of 220 days. Flight frequency and duration were assessed from elevated and constant heart rate, and the absence of flight was used to quantify the duration of flightlessness, which lasted, on average, 36 +/- 8 days (mean +/- SD). Using a period of four weeks before and four weeks after the flightless period, we found that dive depth (ranging from 1 to 2 m, on average) and daily diving time did not vary during the course of the study. Daily metabolic rate increased by 9%, and resting metabolic rate by 12% from the pre-molt period to the flightless period and remained high during the post-molt period. This study indicates that the energetic costs of replacing flight remiges in female eiders are substantial, although this is not associated with any change in foraging effort, which suggests that female Common Eiders lose mass during wing molt. Finally, estimates of energy savings associated with the total absence of flights during wing molt represent 6% of daily metabolic rate or 14% of resting metabolic rate. This finding contrasts with the classical view that little or no benefit is associated with a flightless condition. We suggest that such energy savings may have favored the evolution of temporary flightlessness in diving birds.     

Ground cover impacts on sediment and phosphorus export from manured riparian pasture

Maintaining pasture ground cover is important in preventing environmental degradation of grasslands and associated riparian areas. The objective of this work was to determine the effect of ground cover on sediment and P export from pastured riparian areas under simulated rainfall events. Plots were established on two sites in the North Carolina Piedmont: a 10% slope with Appling sandy loam soils (fine, kaolinitic, thermic Typic Kanhapludults) and a 20% slope with Wedowee sandy loam soils (fine, kaolinitic, thermic Typic Kanhapludults), both with mixed tall fescue (Festuca arundinacea Schreb.)-dallisgrass (Paspalum dilatatum Poir.) vegetation. Existing forage stands were modified to represent a range of ground cover levels: 0, 45, 70, and 95% (bare ground, low, medium, and high cover, respectively), and amended with beef steer (Bos taurus) feces and urine (about 10 kg P ha(-1)). Mean runoff volume from bare ground was generally twice that observed from low, medium, and high levels of cover, which were similar. For all rainfall events combined, export of dissolved reactive P was greatest (P < 0.1) at bare ground and was reduced 31% at low cover, which did not differ from medium or high cover. Mean total Kjeldahl P export was greater (P < 0.001) from bare ground than from other cover levels. Results indicate that riparian bare areas can contribute substantial sediment (>215 kg ha(-1)) and P (0.7 kg P ha(-1)) to surface waters during heavy rainfall, whereas export may be reduced equally well by low cover (45%) as by high cover.     

Comparison of Escherichia coli and Campylobacter jejuni transport in saturated porous media

Due to the difficulties in testing for specific pathogens, water samples are tested for the presence of nonpathogenic indicator organisms to determine whether a water supply has been contaminated by fecal material. An implicit assumption in this approach is that where pathogenic microorganisms are present fecal indicator organisms are present as well; yet surprisingly few studies have been conducted that directly compare the transport of indicator organisms with pathogenic organisms in ground water environments. In this study we compared the cell properties and transport of Escherichia coli, a commonly used indicator organism, and Campylobacter jejuni, an important enteropathogen commonly found in agricultural wastes, through saturated porous media. Differences in cell properties were determined by measuring cell geometry, hydrophobicity, and electrophoretic mobility. Transport differences were determined by conducting miscible displacement experiments in laboratory columns. Under the experimental conditions tested, C. jejuni was much more negatively charged and more hydrophobic than E. coli. In addition, C. jejuni cells were slightly longer, narrower, and less spherical than E. coli. The variations in cell properties, primarily surface charge, resulted in significant differences in transport between these two microorganisms, with the transport of C. jejuni exceeding that of E. coli when conditions favored low attachment rates, thus calling into question the usefulness of using E. coli as an indicator organism for this important pathogen.