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31.
Policy shocks affect the rent distribution in long-term contracts, which can lead to such contracts being renegotiated. We seek an understanding of what aspects of contract design, in the face of a substantial policy shock, affect the propensity to renegotiate. We test our hypotheses using data on U.S. coal contracts after the policy shock of the 1990 Clean Air Act Amendments. Contracts are divided into two categories, those that were renegotiated following the shock and those that were not. Characteristics of the contract are used to explain whether or not the contract was ultimately renegotiated. Results provide guidance on rent re-distribution and contract renegotiation more generally and are applicable to contemporary policy issues such as climate change legislation. 相似文献
32.
Animals adjust their antipredator behavior according to environmental variation in risk, and to account for their ability
to respond to threats. Intrinsic factors that influence an animal’s ability to respond to predators (e.g., age, body condition)
should explain variation in antipredator behavior. For example, a juvenile might allocate more time to vigilance than an adult
because mortality as a result of predation is often high for this age class; however, the relationship between age/vulnerability
and antipredator behavior is not always clear or as predicted. We explored the influence of intrinsic factors on yellow-bellied
marmot (Marmota flaviventris) antipredator behavior using data pooled from 4 years of experiments. We hypothesized that inherently vulnerable animals
(e.g., young, males, and individuals in poor condition) would exhibit more antipredator behavior prior to and immediately
following conspecific alarm calls. As expected, males and yearlings suppressed foraging more than females and adults following
alarm call playbacks. In contrast to predictions, animals in better condition respond more than animals in below average condition.
Interestingly, these intrinsic properties did not influence baseline time budgets; animals of all ages, sexes, and condition
levels devoted comparable amounts of time to foraging prior to alarm calls. Our results support the hypothesis that inherent
differences in vulnerability influence antipredator behavior; furthermore, it appears that a crucial, but poorly acknowledged,
interaction exists between risk and state-dependence. Elevated risk may be required to reveal the workings of state-dependent
behavior, and studies of antipredator behavior in a single context may draw incomplete conclusions about age- or sex-specific
strategies. 相似文献
33.
34.
Mariane de Fátima Yukie Maeda Maria de Lourdes Brizot Maria Augusta Bento Cicaroni Gibelli Silvia Maria Ibidi Werther Brunow de Carvalho Mara Sandra Hoshida Clarisse Martins Machado Ester Cerdeira Sabino Lea Campos de Oliveira da Silva Thomas Jaenisch Maria Cássia Jacintho Mendes-Correa Philippe Mayaud Rossana Pulcinelli Vieira Francisco HC-FMUSP-Obstetric COVID Study Group 《黑龙江环境通报》2021,41(8):998-1008
35.
Dyssegmental dysplasia,Silverman-Handmaker type: prenatal ultrasound findings and molecular analysis
36.
Kathryn Connors Sasowsky Thomas W. Gardner 《Journal of the American Water Resources Association》1991,27(1):7-18
ABSTRACT: A grid cell geographic information system (GIS) is used to parameterize SPUR, a quasi-physically based surface runoff model in which a watershed is configured as a set of stream segments and contributing areas. GIS analysis techniques produce various watershed configurations by progressive simplification of a stream network delineated from digital elevation models (DEM). We used three watershed configurations: ≥ 2nd, ≥ 4th, and ≥ 13th Shreve order networks, where the watershed contains 28, 15, and 1 channel segments with 66, 37, and 3 contributing areas, respectively. Watershed configuration controls simulated daily and monthly sums of runoff volumes. For the climatic and topographic setting in southeastern Arizona the ≥ 4th order configuration of the stream network and contributing areas produces results that are typically as good as the ≥ 2nd order network. However both are consistently better than the ≥ 13th order configuration. Due to the degree of parameterization in SPUR, model simulations cannot be significantly improved by increasing watershed configuration beyond the ≥ 4th order network. However, a range of Soil Conservation Service curve numbers derived from rainfall/runoff data can affect model simulations. Higher curve numbers yield better results for the ≥ 2nd order network while lower curve numbers yield better results for the ≥ 4th order network. 相似文献
37.
Ecosystem mapping methods for British Columbia 总被引:2,自引:0,他引:2
38.
Human activities release tremendous amounts of nitrogenous compounds into the atmosphere. Wet and dry deposition distributes this airborne nitrogen (N) on otherwise pristine ecosystems. This eutrophication process significantly alters the species composition of native grasslands; generally a few nitrophilic plant species become dominant while many other species disappear. The functional equilibrium model predicts that, compared to species that decline in response to N enrichment, nitrophilic grass species should respond to N enrichment with greater biomass allocation aboveground and reduced allocation to roots and mycorrhizas. The mycorrhizal feedback hypothesis states that the composition of mycorrhizal fungal communities may influence the composition of plant communities, and it predicts that N enrichment may generate reciprocal shifts in the species composition of mycorrhizal fungi and plants. We tested these hypotheses with experiments that compared biomass allocation and mycorrhizal function of four grass ecotypes (three species), two that gained and two that lost biomass and cover in response to long-term N enrichment experiments at Cedar Creek and Konza Long-Term Ecological Research grasslands. Local grass ecotypes were grown in soil from their respective sites and inoculated with whole-soil inoculum collected from either fertilized (FERT) or unfertilized (UNFERT) plots. Our results strongly support the functional equilibrium model. In both grassland systems the nitrophilic grass species grew taller, allocated more biomass to shoots than to roots, and formed fewer mycorrhizas compared to the grass species that it replaced. Our results did not fully support the hypothesis that N-induced changes in the mycorrhizal fungal community were drivers of the plant community shifts that accompany N eutrophication. The FERT and UNFERT soil inoculum influenced the growth of the grasses differently, but this varied with site and grass ecotype in both expected and unexpected ways suggesting that ambient soil fertility or other factors may be interacting with mycorrhizal feedbacks. 相似文献
39.
Lea Sebastien 《Local Environment》2017,22(4):461-477
Not In My Back Yard (NIMBY) supporters are presented as citizens in opposition to local developments due to their spatial proximity. However, these conflicts have proven much more complex than the NIMBY concept can explain. The objective of this paper is to provide a framework to facilitate the understanding of opposition movements and how they can affect society at large, triggering social change. The conceptual framework is applied to a case of local opposition to a landfill project in Essonne, France. Through the analysis of the structure of the opposition movement and its changes over time, the author shows how it can evolve into a social movement that enriches democracy through the constitution of four types of capital: social, scientific, patrimonial and political. The author argues that scientific and patrimonial capitals allow social capital to evolve into political capital. The shift from being a self-interest to a civic interest movement is called enlightened resistance, which reveals local public interest, called territorial interests. When studying environmental controversies, the author emphasises the importance of recognizing the evolution through time of (1) social landscape, (2) different types of legitimate knowledge, (3) the role of place attachment, and (4) the political dimension of identities. 相似文献
40.