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971.
972.
973.
Matthias Karl Richard F. Wright Tore F. Berglen Bruce Denby 《International Journal of Greenhouse Gas Control》2011,5(3):439-447
Use of amines is one of the leading technologies for post-combustion carbon dioxide capture from gas and coal-fired power plants. This study assesses the potential environmental impact of emissions to air that result from use of monoethanol amine (MEA) as an absorption solvent for the capture of carbon dioxide (CO2). Depending on operation conditions and installed reduction technology, emissions of MEA to the air due to solvent volatility losses are expected to be in the range of 0.01–0.8 kg/tonne CO2 captured. Literature data for human and environmental toxicity, together with atmospheric dispersion model calculations, were used to derive maximum tolerable emissions of amines from CO2 capture. To reflect operating conditions with typical and with elevated emissions, we defined a scenario MEA-LOW, with emissions of 40 t/year MEA and 5 t/year diethyl amine (DEYA), and a scenario MEA-HIGH, with emissions of 80 t/year MEA and 15 t/year DEYA. Maximum MEA deposition fluxes would exceed toxicity limits for aquatic organisms by about a factor of 3–7 depending on the scenario. Due to the formation of nitrosamines and nitramines, the estimated emissions of DEYA are close to or exceed safety limits for drinking water and aquatic ecosystems. The “worst case” scenario approach to determine maximum tolerable emissions of MEA and other amines is in particular useful when both expected environmental loads and the toxic effects are associated with high uncertainties. 相似文献
974.
Thermal constraints on development are often invoked to predict insect distributions. These constraints tend to be characterized in species distribution models (SDMs) by calculating development time based on a constant lower development temperature (LDT). Here, we assessed whether species-specific estimates of LDT based on laboratory experiments can improve the ability of SDMs to predict the distribution shifts of six U.K. butterflies in response to recent climate warming. We find that species-specific and constant (5 degrees C) LDT degree-day models perform similarly at predicting distributions during the period of 1970-1982. However, when the models for the 1970-1982 period are projected to predict distributions in 1995-1999 and 2000-2004, species-specific LDT degree-day models modestly outperform constant LDT degree-day models. Our results suggest that, while including species-specific physiology in correlative models may enhance predictions of species' distribution responses to climate change, more detailed models may be needed to adequately account for interspecific physiological differences. 相似文献
975.
Richard Haynes 《Journal of Agricultural and Environmental Ethics》2011,24(2):105-106
976.
Peter Michael Link Uwe A. Schneider Richard S. J. Tol 《Environmental Modeling and Assessment》2011,16(4):413-429
Using a bioeconomic model of the cod (Gadus morhua) and capelin (Mallotus villosus) fisheries of the Barents Sea, this study assesses the role of the fishermen’s behavior in reducing or intensifying the effects
on the stocks caused by altered population dynamics. The analysis focuses on the economic development of the fisheries employing
a coupled stock size–hydrography-based fishing strategy, which attempts to maximize returns from fishing over a given number
of fishing periods. Results show that if the fishing strategy is based on a short optimization period of only two fishing
periods, changes in population dynamics have a direct influence on the returns from fishing due to the strong pressure on
the stocks applied by the fisheries. If the strategy is based on a longer optimization period, fishing activities may be deferred
to allow for stock regrowth, which improves the economic performance of the fisheries. However, in that case, the relationship
between population dynamics and fishing activities becomes less clear, as even a reduction of the carrying capacities of the
two species allows for an increase in the amount of fish landed without causing a stock collapse due to an increased efficiency
of fleet utilization. The simulations indicate that management considerations and the time horizon of the fishing strategy
dominate the influence of altered population dynamics on the development of the stocks considered in the model. 相似文献
977.
Kim K Steuerwald AJ Parsons PJ Fujimoto VY Browne RW Bloom MS 《Journal of environmental monitoring : JEM》2011,13(9):2413-2419
Humans are exposed to concentrations of multiple trace elements through a variety of background sources; many are suspected reproductive toxicants. Prior to investigating associations between trace elements and human reproductive health, potential biomarkers of exposure should be characterized by sources of variability in the population at risk. Factors influencing elemental exposure should also be identified to ensure their consideration as potential confounding variables. The principal aim of this study is to characterize sources of variability for 19 trace elements measured in urine specimens collected from 55 women and 36 male partners completing a 1st cycle of in vitro fertilization (IVF). Urine specimens were analyzed using a biomonitoring method based on inductively coupled plasma-mass spectrometry (ICP-MS). Randomly selected urine specimens (~6%) were analyzed in duplicate, and these data were used to characterize sources of variability. Nine trace elements including As, Ba, Cd, Cs, Co, Cu, Mn, Mo, and Zn, were quantified in most specimens, indicating their utility in future epidemiologic studies of trace elements exposure and IVF outcomes. With few exceptions, normalizing urine using the traditional creatinine-correction procedure, or an alternative approach based on a linear regression model, increased residual variability only slightly. Sex and race appear to be important factors to consider in epidemiologic studies conducted in this population. Urine concentrations for most elements are similar to those reported in the 2005-2006 National Health and Nutrition Examination Survey (NHANES); however, differences in others may indicate regional trends or a unique exposure history for this infertile study population. 相似文献
978.
979.
Edna González-Bernal Gregory P. Brown Elisa Cabrera-Guzmán Richard Shine 《Behavioral ecology and sociobiology》2011,65(7):1367-1375
The foraging sites selected by an ambush forager can strongly affect its feeding opportunities. Foraging cane toads (Rhinella marina) typically select open areas, often under artificial lights that attract insects. We conducted experimental trials in the
field, using rubber mats placed under lights, to explore the influence of substrate color and rugosity on prey availability
(numbers, sizes, and types of insects) and toad foraging success. A mat's color (black vs. white) and rugosity (smooth vs.
rough) did not influence the numbers, sizes, or kinds of insects that were attracted to it, but toads actively preferred to
feed on rugose white mats (50% of prey-capture events, vs. a null of 25%). White backgrounds provided better visual contrast
of the (mostly dark) insects, and manipulations of prey color in the laboratory showed that contrast was critical in toad
foraging success. Insects landing on rugose backgrounds were slower to leave, again increasing capture opportunities for toads.
Thus, cane toads actively select backgrounds that maximize prey-capture opportunities, a bias driven by the ways that substrate
attributes influence ease of prey detection and capture rather than by absolute prey densities. 相似文献
980.
Robert S. Bolia Richard L. McKinley 《International journal of occupational safety and ergonomics》2013,19(3):309-319
Response times (RT) in an audio-visual target acquisition task were collected from 3 participants while wearing either circumaural earmuffs, foam earplugs, or no hearing protection. Analyses revealed that participants took significantly longer to locate and identify an audio-visual target in both hearing protector conditions than they did in the unoccluded condition, suggesting a disturbance of the cues used by listeners to localize sounds in space. RTs were significantly faster in both hearing protector conditions than in a non-audio control condition, indicating that auditory localization was not completely disrupted. Results are discussed in terms of safety issues involved with wearing hearing protectors in an occupational environment. 相似文献