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171.
James T. Spartz Leona Yi-Fan Su Robert Griffin Dominique Brossard Sharon Dunwoody 《Environmental Communication: A Journal of Nature and Culture》2017,11(1):1-16
This online experiment explored how contextual information embedded in new media channels such as YouTube may serve as normative social cues to users. Specifically, we examined whether the number of views listed under a YouTube video about climate change would elicit inferences regarding how “others” feel about the climate issue and, consequently, might influence perceptions of issue salience. Participants in this experiment were exposed to a YouTube video about climate change using two experimental conditions, one providing a small number of views under the video and the second listing a large number of views. Results suggest that the “number of views” cue did, indeed, influence participant perceptions of the importance assigned by other Americans to the issue of climate change. Further, compared to low self-monitoring participants, high self-monitoring participants registered an increase in their own judgment of issue importance. 相似文献
172.
Kingsley?O.?OdigieEmail author Ethel?Khanis Sharon?A.?Hibdon Patricia?Jana Alberto?Araneda Roberto?Urrutia A.?Russell?Flegal 《Regional Environmental Change》2016,16(4):1089-1096
Temporal changes in the amounts of trace elements (As, Co, Cu, Mn, Ni, Pb, and Zn) and their correlations with temporal changes in charcoal abundance in age-dated sediments collected from Lake Thompson in Patagonia, Chile, attest to the substantial pyrogenic remobilization of contaminants that occurred in Patagonia during the mid-1900s. This remobilization was concurrent with the extensive slash and burn period in the region during that period. The changes in concentrations of Co, Cu, and Ni in relation to charcoal abundance in the lacustrine sediments over time were small compared to those of As, Mn, Pb, and Zn. However, the relatively low enrichment factors of all those trace elements, normalized to Fe, indicate that they were predominantly derived from local, natural sources impacted by fires rather than industrial sources. The primarily local source of Pb in the sediments was corroborated by the temporal consistency of its isotopic ratios (206Pb/207Pb:208Pb/206Pb), which were similar to previously reported values for natural lead in Central and Southern Chile. However, the pyrogenic remobilization of both natural and industrial trace elements by forest fires in Chile and elsewhere is expected to rise as a consequence of climate change, which is projected to increase both the frequency and intensity of forest fires on a global scale. 相似文献
173.
Laban Musinguzi Jackson Efitre Konstantine Odongkara Richard Ogutu-Ohwayo Fredrick Muyodi Vianny Natugonza Mark Olokotum Sharon Namboowa Shamim Naigaga 《Environment, Development and Sustainability》2016,18(4):1255-1273
Fisheries resources support livelihoods of fishing communities but are threatened by over-exploitation, habitat degradation, pollution, invasive species and climate change. Unlike the other threats, climate change has received limited consideration and reducing its risks requires appropriate adaptation strategies. This study used quantitative and qualitative methods to generate knowledge on fishers’ perceptions of climate change, changes in climate variables and their impacts on livelihoods, adaptation strategies, constraints to adaptation and required interventions to promote adaptation strategies that would enable fishers to build resilience to sustain their livelihoods. We found that fishers were aware of changes in climate conditions manifested by unpredictable seasons, floods and droughts. Fishing remained the main livelihood activity. However, the dominance of fishes had changed from Nile tilapia (Oreochromis niloticus L.) to the African catfish (Clarias gariepinus Burchell). Floods and droughts were associated with damage to gears, boats, landing sites and changes in fish catches and sizes, income from fishing and fish consumption. The fishers adapted by increasing time on fishing grounds and changing target species and fishing gear among other things. Some innovative fishers diversified to high-value crops and livestock. This increased their income beyond what was solely earned from fishing which provided an incentive for some of them to quit fishing. Livelihood diversification was enhanced by use of communications technology, membership of social groups, increasing fishing days and fishing experience. Adaptation was, however, constrained by limited credit, awareness and access to land, which require interventions such as improving access to credit, irrigation facilities, appropriate planting materials and awareness raising. We identified adaptation strategies, which if promoted and their constraints addressed, could increase resilience of fishers to the influence of climate change and sustain their livelihoods. 相似文献
174.
Ona Sakaliene Sharon K. Papiernik William C. Koskinen Kurt A. Spokas 《Journal of environmental science and health. Part. B》2013,48(6):641-647
This study was undertaken to determine sorption coefficients of eight herbicides (alachlor, amitrole, atrazine, simazine, dicamba, imazamox, imazethapyr, and pendimethalin) to seven agricultural soils from sites throughout Lithuania. The measured sorption coefficients were used to predict the susceptibility of these herbicides to leach to groundwater. Soil-water partitioning coefficients were measured in batch equilibrium studies using radiolabeled herbicides. In most soils, sorption followed the general trend pendimethalin > alachlor > atrazine~ amitrole~ simazine > imazethapyr > imazamox > dicamba, consistent with the trends in hydrophobicity (log Kow) except in the case of amitrole. For several herbicides, sorption coefficients and calculated retardation factors were lowest (predicted to be most susceptible to leaching) in a soil of intermediate organic carbon content and sand content. Calculated herbicide retardation factors were high for soils with high organic carbon contents. Estimated leaching times under saturated conditions, assuming no herbicide degradation and no preferential water flow, were more strongly affected by soil textural effects on predicted water flow than by herbicide sorption effects. All herbicides were predicted to be slowest to leach in soils with high clay and low sand contents, and fastest to leach in soils with high sand content and low organic matter content. Herbicide management is important to the continued increase in agricultural production and profitability in the Baltic region, and these results will be useful in identifying critical areas requiring improved management practices to reduce water contamination by pesticides. 相似文献
175.
This study develops a modeling approach for simulating and evaluating entrapped light nonaqueous-phase liquid (light NAPL-LNAPL) dissolution and transport of the solute in a fractured permeable aquifer (FPA). The term FPA refers to an aquifer made of porous blocks of high permeability that embed fractures. The fracture network is part of the domain characterized by high permeability and negligible storage. Previous studies show that sandstone aquifers often represent FPAs. The basic model developed in this study is a two-dimensional (2-D) model of permeable blocks that embed oblique equidistant fractures with constant aperture and orientation. According to this model, two major parameters govern NAPL dissolution and transport of the solute. These parameters are: 1) the dimensionless interphase mass transfer coefficient, K(f0), and 2) the mobility number, N(M0). These parameters represent measures of heterogeneity affecting flow, NAPL dissolution, and transport of the solute in the domain. The parameter K(f0) refers to the rate at which organic mass is transferred from the NAPL into the water phase. The parameter N(M0) represents the ratio of flow through the porous blocks to flow through the fracture network in regions free of entrapped NAPL. It also provides a measure of groundwater flow bypassing regions contaminated by entrapped NAPL. In regions contaminated by entrapped NAPL our simulations have often indicated very low permeability of the porous blocks, enabling a significant increase of the fracture flow at the expense of the permeable block flow. Two types of constitutive relationships also affect the rate of FPA cleanup: 1) the relationship between the saturation of the entrapped NAPL and the permeability of the porous blocks, and 2) the relationships representing effects of the entrapped NAPL saturation and the permeable block flow velocity on rates of interphase mass transfer. This study provides basic tools for evaluating the characteristics of pump-and-treat cleanup of FPAs by referring to sets of parameters and constitutive relationships typical of FPAs. The numerical simulations carried out in this study show that at high initial saturation of the entrapped NAPL, during initial stages of the FPA cleanup the contaminant concentration increases, but later it decreases. This phenomenon originates from significant groundwater bypassing the NAPL entrapped in the permeable blocks via the fracture network. 相似文献
176.
Schwede Donna B. LeDuc Sharon K. Otte Tanya L. 《Water, Air, & Soil Pollution: Focus》2001,1(5-6):59-66
The National Oceanic and Atmospheric Administration's Multi-Layer Model (NOAA-MLM) is used by several operational dry deposition networks for estimating the deposition velocity of O3, SO2, HNO3, and particles. The NOAA-MLM requires hourly values of meteorological variables. Since collection of on-site meteorology can be expensive, a study was performed to compare NOAA-MLM predicted deposition velocitiesusing modeled meteorological data in lieu of on-site meteorological data. NOAA-MLM was run for three sites in the Clean Air Status and Trends Network using on-site data as well as the output of two mesoscale meteorological models, Eta and MM5. The differences between the deposition velocities predictedusing the mesoscale models and those predicted using the on-sitemeteorological measurements ranged from –0.001 to 0.106 cm s-1 and were within the model error determined in NOAA-MLM evaluation studies. This research shows that the NOAA-MLM is particularly sensitive to differences in atmospheric turbulence,soil moisture budget, and canopy wetness.(On assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina.) (author for correspondence, e-mail 相似文献
177.
Putting Theory into Practice: Wildlife Health in Conservation 总被引:4,自引:0,他引:4
178.
Disappearance and dispersal of Spermophilus elegans juveniles in relation to behavior 总被引:1,自引:0,他引:1
Sharon Pfeifer 《Behavioral ecology and sociobiology》1982,10(4):237-243
Summary Patterns of disappearance and dispersal of Spermophilus elegans juveniles during the first 6-weeks postemergence were compared for 1977 and 1978 and related to quantitative and qualitative changes in social interaction involving juveniles.Juvenile disappearance (emigration or mortality) and dispersal within the study site varied between the sexes within and between years. Female disappearance and dispersal were significantly greater in 1977, and male losses in 1978 significantly exceeded male losses in 1977. Greater female loss in 1977 resulted in total male — female losses being equivalent, whereas in 1978 juvenile loss was strongly biased toward males by the end of the 6-week period.Greater female loss in 1977 was attributed primarily to increased aggression between female juveniles in that year because of larger average litter size with more females per litter. Increased disappearance of males in 1978 showed no correlation with litter size or relative increase in number of males per litter. Male young interacted with individuals of several age/sex classes, and a possible behavioral influence on male disappearance was increased aggressiveness by yearling males toward juvenile males in 1978.Behavior appeared to act as a proximate factor in juvenile disappearance and dispersal, and the observed differences between how male and female juveniles interacted in 1977 and 1978 were hypothesized to reflect the operation of different selective pressures to increase individual male or female fitness. 相似文献
179.
This research investigates how creativity is influenced by externally imposed structure (how structured the task is), internal, cognitively produced, structure (how structured the individuals' cognitive style is), and the interaction between these two factors. Reviewing past literature, we find a contradiction. Studies that focused on the situational perspective found that externally imposed structure increases creativity. In contrast, studies that focused on the individual found that systematic (structured) cognitive style decreases creativity. In two empirical studies we investigated this seeming contradiction. We focused on two aspects of externally imposed structure: The construction of the task (Study 1) and the instructions provided (Study 2). The findings of both studies revealed that creativity was higher under structured conditions. We also show that intuitive individuals are more creative than systematic individuals, but mainly under free conditions, where structure is not externally imposed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
180.