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1.
L. Jeffrey Lefkoff Donald R. Kendall 《Journal of the American Water Resources Association》1996,32(3):451-463
ABSTRACT: A non-linear optimization model is applied to the California State Water Project (SWP) and portions of the Central Valley Project (CVP). The model accounts for the major hydrologic, regulatory, and operational features of both projects. The model maximizes long-term SWP yields over a 70-year period, using a quarterly time step. The potential for increased yield associated with a proposed facility improvement is evaluated with the model. The proposed facility is an extension of the Folsom-South Canal, which would allow water to be conveyed from the American River below Folsom Reservoir into New Melones Reservoir on the Stanislaus River or into the California Aqueduct. Model results indicate that extension of the Folsom-South Canal has the potential to increase SWP yields by 13 percent. 相似文献
2.
Amit Kapur Hendrik G. van Oss Gregory Keoleian Stephen E. Kesler Alissa Kendall 《Journal of Material Cycles and Waste Management》2009,11(2):155-165
A country-level stock and flow model for cement, an important construction material, was developed based on a material flow
analysis framework. Using this model, the contemporary cement cycle of the United States was constructed by analyzing production,
import, and export data for different stages of the cement cycle. The United States currently supplies approximately 80% of
its cement consumption through domestic production and the rest is imported. The average annual net addition of in-use new
cement stock over the period 2000–2004 was approximately 83 million metric tons and amounts to 2.3 tons per capita of concrete.
Nonfuel carbon dioxide emissions (42 million metric tons per year) from the calcination phase of cement manufacture account
for 62% of the total 68 million tons per year of cement production residues. The end-of-life cement discards are estimated
to be 33 million metric tons per year, of which between 30% and 80% is recycled. A significant portion of the infrastructure
in the United States is reaching the end of its useful life and will need to be replaced or rehabilitated; this could require
far more cement than might be expected from economic forecasts of demand for cement. 相似文献
3.
4.
Forest policymakers, public lands managers, and scientists in the Pacific Northwest (USA) seek ways to evaluate the landscape-level
effects of policies and management through the multidisciplinary development and application of spatially explicit methods
and models. The Interagency Mapping and Analysis Project (IMAP) is an ongoing effort to generate landscape-wide vegetation
data and models to evaluate the integrated effects of disturbances and management activities on natural resource conditions
in Oregon and Washington (USA). In this initial analysis, we characterized the spatial distribution of forest and range land
development in a four-county pilot study region in central Oregon. The empirical model describes the spatial distribution
of buildings and new building construction as a function of population growth, existing development, topography, land-use
zoning, and other factors. We used the model to create geographic information system maps of likely future development based
on human population projections to inform complementary landscape analyses underway involving vegetation, habitat, and wildfire
interactions. In an example application, we use the model and resulting maps to show the potential impacts of future forest
and range land development on mule deer (Odocoileus hemionus) winter range. Results indicate significant development encroachment and habitat loss already in 2000 with development located
along key migration routes and increasing through the projection period to 2040. The example application illustrates a simple
way for policymakers and public lands managers to combine existing data and preliminary model outputs to begin to consider
the potential effects of development on future landscape conditions. 相似文献
5.
6.
The effects of pathway configuration, landmarks and stress on environmental cognition 总被引:1,自引:0,他引:1
Gary W. Evans Mary Anne Skorpanich Tommy Grling Kendall J. Bryant Brian Bresolin 《Journal of environmental psychology》1984,4(4):323-335
The results of this study indicate that manipulations of the pathway grid configuration and landmark placement in a setting cause changes in environmental knowledge. These experimental manipulations were accomplished using a realistic, dynamic simulation technique at the Berkeley Environmental Simulation Laboratory. Measures of environmental knowledge include: memory for incidental information along the simulated urban route, accuracy of route maps, relocation memory for scenes along the route, and questionnaire measures. Data are also presented showing both positive and negative effects of stress from noise on the processes of environmental cognition. 相似文献
7.
Caitlin D. Kuempel Kendall R. Jones James E.M. Watson Hugh P. Possingham 《Conservation biology》2019,33(6):1350-1359
Marine protected areas (MPAs) are a critical defense against biodiversity loss in the world's oceans, but to realize near-term conservation benefits, they must be established where major threats to biodiversity occur and can be mitigated. We quantified the degree to which MPA establishment has targeted stoppable threats (i.e., threats that can be abated through effectively managed MPAs alone) by combining spatially explicit marine biodiversity threat data in 2008 and 2013 and information on the location and potential of MPAs to halt threats. We calculated an impact metric to determine whether countries are protecting proportionally more high- or low-threat ecoregions and compared observed values with random protected-area allocation. We found that protection covered <2% of ecoregions in national waters with high levels of abatable threat in 2013, which is ∼59% less protection in high-threat areas than if MPAs had been placed randomly. Relatively low-threat ecoregions had 6.3 times more strict protection (International Union for Conservation of Nature categories I–II) than high-threat ecoregions. Thirty-one ecoregions had high levels of stoppable threat but very low protection, which presents opportunities for MPAs to yield more significant near-term conservation benefits. The extent of the global MPA estate has increased, but the establishment of MPAs where they can reduce threats that are driving biodiversity loss is now urgently needed. 相似文献
8.
Opportunity and recognition isolation can lead directly to reproductive isolation, the former via divergence in the location
and timing of breeding, and the latter via differential mate preferences. We describe the potential significance of these
factors in the maintenance of reproductive isolation in a clade of triplefin fishes that occur sympatrically around coastal
New Zealand. Specifically, we investigate the roles of spawning time and nesting habitat in promoting opportunity isolation,
and of interspecific variation in male body length and breeding colouration in promoting recognition isolation. The triplefin
species investigated are reproductively active over several months and show high overlap in breeding times, thus rejecting
temporal isolation as a mechanism. Differences in nesting habitats resulted in a reduced probability of encounter between
some species, especially between sister-species pairs. Interspecific colour differences generally decreased during the reproductive
period, and males of sister-species pairs showed no interspecific colour differences in the ultraviolet light spectrum, thus
mate selection based on male colour patterns is unlikely to lead to premating isolation. Finally, males of closely related
triplefin species differed in body length, a secondary sexual trait often involved in assortative mating. Thus, spatial differences
in nesting habitats reduce the chances of encountering allospecific mates, which may facilitate opportunity isolation and
differences in male length, possibly related to species-specific female selection on male body size, may lead to recognition
isolation. The combination of limited spatial overlap in nesting habitat and differences in male body size may facilitate
species assortative mating in sympatry or parapatry. 相似文献
9.
Unstructured Individual Variation and Demographic Stochasticity 总被引:1,自引:0,他引:1
10.
Helen S. Findlay Michael A. Kendall John I. Spicer Stephen Widdicombe 《Marine Biology》2010,157(4):725-735
Ocean acidification and global warming are occurring concomitantly, yet few studies have investigated how organisms will respond
to increases in both temperature and CO2. Intertidal microcosms were used to examine growth, shell mineralogy and survival of two intertidal barnacle post-larvae,
Semibalanus balanoides and Elminius modestus, at two temperatures (14 and 19°C) and two CO2 concentrations (380 and 1,000 ppm), fed with a mixed diatom-flagellate diet at 15,000 cells ml−1 with flow rate of 10 ml−1 min−1. Control growth rates, using operculum diameter, were 14 ± 8 μm day−1 and 6 ± 2 μm day−1 for S. balanoides and E. modestus, respectively. Subtle, but significant decreases in E. modestus growth rate were observed in high CO2 but there were no impacts on shell calcium content and survival by either elevated temperature or CO2. S. balanoides exhibited no clear alterations in growth rate but did show a large reduction in shell calcium content and survival under
elevated temperature and CO2. These results suggest that a decrease by 0.4 pH(NBS) units alone would not be sufficient to directly impact the survival of barnacles during the first month post-settlement.
However, in conjunction with a 4–5°C increase in temperature, it appears that significant changes to the biology of these
organisms will ensue. 相似文献