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501.
Miriam Fischlein Timothy M. Smith Elizabeth J. Wilson 《Environmental Science & Policy》2009,12(7):778-790
An important subset of the utility sector has been scarcely explored for its ability to reduce carbon dioxide emissions: consumer-owned electric utilities significantly contribute to U.S. greenhouse gas emissions, but are often excluded from energy efficiency and renewable energy policies. They sell a quarter of the nation's electricity, yet the carbon impact of these sales is not well understood, due to their small size, unique ownership models, and high percentage of purchased power for distribution. This paper situates consumer-owned utilities in the context of emerging U.S. climate policy, quantifying for the first time the state-by-state carbon impact of electricity sales by consumer-owned utilities. We estimate that total retail sales by consumer-owned utilities account for roughly 568 million metric tons of CO2 annually, making this sector the 7th largest CO2 emitter globally, and examine state-level carbon intensities of the sector in light of the current policy environment and the share of COU distribution in the states. Based on efficiency and fuel mix pathways under conceivable regulations, carbon scenarios for 2030 are developed. 相似文献
502.
Elizabeth Wilson 《Journal of Environmental Planning and Management》1999,42(4):581-598
Capacity for environmental protection is important in developed and transitional countries, but the latter sometimes present a paradox where capacity has been created at the same time as public pressure and awareness has diminished. Slovakia presents a particular paradox, as its new democratic institutions have proved especially fragile. This paper adopts a framework developed by Janicke and Weidner in crossnational studies which implies that the use made of environmental capacity is a function of institutional, informational and structural conditions. By analysing the key features of the Slovakian environmental policy process in the context of these conditions, the paper confirms the utility of the model, and points to the prospects for future policy implementation. 相似文献
503.
Elizabeth L. Chalecki Peter H. Gleick 《Journal of the American Water Resources Association》1999,35(6):1657-1665
ABSTRACT: An examination of the metadata for almost 900 bibliographic references on the effects of climate change and variability on U.S. water resources reveals strengths and weaknesses in our current knowledge. Considerable progress has been made in the modeling of climate change effects on first-order systems such as regional hydrology, but significant work remains to be done in understanding subsequent effects on the second-, third-, and fourth-order economic and social systems (e.g., agriculture, trade balance, and national economic development) that water affects. In order to remedy a recently-revealed lack of understanding about climate change on the part of the public, climate and water scientists should collaborate with social scientists in illuminating the effects of climate change and variability on the systems that affect how and where most people live. 相似文献
504.
Partial migration is thought to be a critical step in the evolution of avian migration, but data on the life history correlates of alternative migratory strategies are extremely limited. We have studied a partially migratory population of American Dippers since 1999. This population is composed of sedentary individuals (residents) that maintain the same territory year round and altitudinal migrants that share winter grounds with residents, but move to higher elevations to breed. We used seven years of data on individually marked birds to (1) determine if individuals consistently use the same migratory strategy, (2) determine if offspring have the same strategy as their parents, and (3) estimate reproductive and survival rates of the two migratory strategies. We evaluate hypotheses for the persistence of partial migration and discuss their implication for the evolution of migration in sedentary populations. Individual American Dippers rarely switched migratory strategy (4/169 monitored more than one year). An individual's strategy, however, was not always that of its parents, indicating that, while migratory behavior may have a genetic component, environmental or social conditions probably influence the migratory strategy that an individual adopts. Sedentary dippers consistently had higher annual productivity (approximately 1.4 more fledglings/year) than migratory dippers, but mark-recapture models suggested that migratory dippers may have slightly higher survival than residents (approximately 3.4%). Migrants were estimated to have lower lifetime reproductive success than residents because their higher survival was insufficient to offset their lower productivity. Our data suggest that alternative migratory strategies in American Dippers are unlikely to be a fixed genetic dimorphism that persists because the two strategies have equal fitness, or because the relative fitness of the two strategies fluctuates over time. Migratory strategies in American Dippers are more likely to be condition dependent, and the two strategies persist because migrants "make the best of a bad job" by moving to higher elevations to breed. Because migrants obtained no fitness benefits by moving to seasonal breeding territories, our data are consistent with the hypothesis that migration could evolve in sedentary populations if competition for limited resources forces some individuals to seek breeding opportunities outside their initial range. 相似文献
505.
Kimberly S. Reece Jan F. Cordes Julie B. Stubbs Karen L. Hudson Elizabeth A. Francis 《Marine Biology》2008,153(4):709-721
Identification of oyster species is still largely based on phenotypic characters that are highly plastic. Prompted by the
proposed introduction of the Asian oyster species Crassostrea ariakensis into the Chesapeake Bay region of the U.S.A., this study uses molecular genetic information to understand the taxonomic framework
surrounding C. ariakensis and to confidently distinguish among various sympatric oyster species. Putative samples of C. ariakensis and other species of cupped oysters from across Asia were collected and phylogenetic analyses were conducted on DNA sequences
of both nuclear (ITS-1) and mitochondrial (COI) regions. Trees generated based on the two independent molecular datasets were
highly congruent, and indicate that many oysters collected for this study as C. ariakensis were originally misidentified. Results also indicate that C. ariakensis, C. hongkongensis and C. nippona are distinct, but closely related species. There is strong support in both analyses for a close relationship between C. gigas and C. sikamea, as well as between C. belcheri and C. gryphoides, and between C. iredalei and C. madrasensis. The parsimony analyses based on these DNA markers, however, did not provide evidence to support C. angulata as a distinct species from C. gigas. Overall, the results emphasize the need for rigorous species identification, and additional extensive and intensive sampling
to more accurately determine relationships among Crassostrea species, define their geographic distributions, and establish existing sympatry patterns. 相似文献
506.
Christy L. Hoffman Angelina V. Ruiz-Lambides Edgar Davila Elizabeth Maldonado Melissa S. Gerald Dario Maestripieri 《Behavioral ecology and sociobiology》2008,62(11):1711-1718
In sexually promiscuous mammals, female reproductive effort is mainly expressed through gestation, lactation, and maternal
care, whereas male reproductive effort is mainly manifested as mating effort. In this study, we investigated whether reproduction
has significant survival costs for a seasonally breeding, sexually promiscuous species, the rhesus macaque, and whether these
costs occur at different times of the year for females and males, namely in the birth and the mating season, respectively.
The study was conducted with the rhesus macaque population on Cayo Santiago, Puerto Rico. Data on 7,402 births and 922 deaths
over a 45-year period were analyzed. Births were concentrated between November and April, while conceptions occurred between
May and October. As predicted, female mortality probability peaked in the birth season whereas male mortality probability
peaked in the mating season. Furthermore, as the onset of the birth season gradually shifted over the years in relation to
climatic changes, there was a concomitant shift in the seasonal peaks of male and female mortality. Taken together, our findings
provide the first evidence of sex differences in the survival costs of reproduction in nonhuman primates and suggest that
reproduction has significant fitness costs even in environments with abundant food and absence of predation. 相似文献
507.
Patterns of shell repair in articulate brachiopods indicate size constitutes a refuge from predation
The cost of overcoming prey defenses relative to the value of internal tissues is a key criterion in predator/prey interactions.
Optimal foraging theory predicts: (1) specific sizes of prey will result in the best returns to predators, and (2) there will
often be a size at which the cost/benefit balance is low enough to effectively exclude predation. Data presented here on styles
of repaired shell damage and size at which injury had been sustained was collected from samples of terebratulide brachiopods
from the Antarctic Peninisula (Liothyrella uva), Falkland Islands (Magellania venosa and Terebratella dorsata) and Chile (M. venosa). The predominant form of damage on shells was indicative of predators attacking the valve margins. The modal size for repaired
damage was more than 10 mm smaller than the modal size for the overall size distribution in each species and there were no
repaired attacks in the largest size classes of any species. These data suggest that size forms a refuge from predation, as
would be predicted by optimal foraging theory. The optimal sizes that predators appeared to attack vary between species, as
do the sizes that provided a refuge from predation. High levels of multiple repairs (19% of the M. venosa population from the Falkland Islands sampled had 2 or more repairs) suggest that the mortality following attack is low, suggesting
that many predators abandon their attacks. 相似文献
508.
509.
The objective of this Incubator is to stimulate research in the area of multiple jobholding (MJH), a long‐neglected topic in organizational behavior. We first discuss the prevalence of, and motivation for, MJH and then discuss possible dangers and benefits of MJH. Throughout, we discuss ideas for future research. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
510.
Renshaw CE Bostick BC Feng X Wong CK Winston ES Karimi R Folt CL Chen CY 《Journal of environmental quality》2006,35(1):61-67
Increasing development of historic farmlands raises questions regarding the fate of pesticides applied when these land were in cultivation. We quantified As and Pb budgets in field soils in two orchards where arsenical pesticides were applied in the early 20th century and a third uncontaminated control field. Sequential extractions and X-ray analyses also were used to determine mineral phases. In addition, we measured metal loads in drainages adjacent to the fields and in two common macroinvertebrate taxa within the wetland at the outlet of the drainages. We find that the applied As and Pb have undergone little vertical redistribution; concentrations of As and Pb in the top 25 cm of contaminated orchard soils are higher than in the uncontaminated control field. However, none of the applied lead arsenate (PbHAsO4) remains in its original mineral phase. Instead, the metals are now primarily adsorbed onto fine silt and clay-sized amorphous oxides and organic matter. Further, physical erosion associated with tilling and replanting appears to have mobilized the fine-particulate-bound As and Pb in one orchard. The remobilized metals are found in sediments in the stream channel draining the tilled orchard. It is unclear if the As and Pb transported sediments are biologically active; average macroinvertebrate metal burdens in the wetland are not elevated above those observed elsewhere in the region. However, little of the mobilized metals may have reached the wetland. These results demonstrate that land use change can significantly impact the retention of arsenical pesticides. 相似文献