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1.
Mitigation under Section 404 of the Clean Water Act: where it comes from, what it means 总被引:2,自引:0,他引:2
The requirement to mitigate impacts to wetlands and streams is a frequently misunderstood policy with a long and complicated
history. We narrate the history of mitigation since the inception of the Clean Water Act Section 404 permit program in 1972,
through struggles between the US Environmental Protection Agency and the US Army Corps of Engineers, through the emerging
importance of wetland conservation on the American political landscape, and through the rise of market-based approaches to
environmental policy. Mitigation, as it is understood today, was not initially foreseen as a component of the Section 404
permitting program, but was adapted from 1978 regulations issued by the Council on Environmental Quality as a way of replacing
the functions of filled wetlands where permit denials were unlikely. EPA and the Corps agreed in 1990 to define mitigation
as the three steps of avoidance, minimization, and compensation, principles which must be applied to permit decisions in the
form of the environmental criteria in EPA’s 404(b)(1) Guidelines. Through the 1980s and 1990s, the compensation component
of mitigation has become nearly the sole focus of mitigation policy development, and has been the subject of numerous guidance
documents and memoranda since 1990. Avoidance and minimization have received far less policy attention, and this lack of policy
development may represent a missed opportunity to implement effective wetland conservation.
相似文献
Morgan RobertsonEmail: |
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3.
This paper introduces a threshold policy with hysteresis (TPH) for the control of one-predator one-prey models. The models studied are the Lotka–Volterra and Rosenzweig–MacArthur
two species density-dependent predator–prey models and the Arditi–Ginzburg nondimensional ratio-dependent model. The proposed
policy (TPH) changes the dynamics of the system in such a way that a bounded oscillation is achieved confined to a region
that does not allow extinction of either species. The policy can be designed by a suitable choice of so called virtual equilibrium
points in a simple and intuitive manner.
相似文献
Amit Bhaya (Corresponding author)Email: |
4.
Though there are wetlands listed by the IUCN and wetland protection areas designated by the government, it is presumed that there would be more wetlands in Korea when they are surveyed and classified according to international wetland criteria, but a considerable amount of area is yet to be identified. Therefore, in order to conduct a systematic status survey on the wetlands of Korea, a wetland classification system needs to be developed first. The objectives of this paper include reviewing international wetland classifications and mapping systems of the USA, Germany, the Netherlands, Japan and North Korea and developing a wetland classification and mapping system appropriate to Korea based on an understanding of the major case examples of wetland types. Then, the developed system was applied to the Phanmun field watershed located at the western DMZ in Korea to conduct a case study. The overall process of a wetland classification and mapping system developed in this study is undertaken as the following from step 1 to step 5. First, wetlands are identified based on three parameters: hydrology, hydrophytes and hydric soil. Second, wetland delineation distinguished wetland areas and non-wetland areas by identifying wetlands through a field survey. Third, an ecological survey is conducted in order to classify wetland characteristics and types for the target area. Ecological survey items include the topography, landscape, biota, pollutant sources and land use status. Fourth, a wetland classification is developed through a hybrid approach based on HGM (the hydrogeomorphic method). Level 1 is classified into inland, estuarine and costal areas. Level 2, the target area, is classified as an eco-region at a watershed level, and level 3 is classified into depression, riverine, slope, flat and fringe areas based on a HGM approach. Level 4 is classified into detailed wetland types based on specific characteristics of wetlands. Level 5 is classified into marsh and swamp based on grasslands and shrubs and forest trees. Level 6 indicates the dominant vegetation communities.
相似文献
Hee-Sun Choi (Corresponding author)Email: Phone: +82-2-8804881Fax: +82-2-8754818 |
5.
A key point in the analysis of dynamical models of biological systems is to handle systems of relatively high dimensions.
In the present paper we propose a method to hierarchically organize a certain type of piecewise affine (PWA) differential
systems. This specific class of systems has been extensively studied for the past few years, as it provides a good framework
to model gene regulatory networks. The method, shown on several examples, allows a qualitative analysis of the asymptotic
behavior of a PWA system, decomposing it into several smaller subsystems. This technique, based on the well-known strongly
connected components decomposition, is not new. However, its adaptation to the non-smooth PWA differential equations turns
out to be quite relevant because of the strong discrete structure underlying these equations. Its biological relevance is
shown on a 7-dimensional PWA system modeling the gene network responsible for the carbon starvation response in Escherichia coli.
相似文献
Laurent Tournier (Corresponding author)Email: |
Jean-Luc GouzéEmail: |
6.
7.
Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.
相似文献
Marienne S. de VilliersEmail: Fax: +27-21-6503434 |
John CooperEmail: |
Peter G. RyanEmail: |
8.
Ryan E. Galt 《Human ecology: an interdisciplinary journal》2008,36(5):655-677
Understanding the factors that influence the adoption of synthetic pesticides has to date overshadowed explanations of variation
in pesticide intensity. I conducted a survey of vegetable farmers in Northern Cartago and the Ujarrás Valley, Costa Rica,
in 2003–2004 with the goal of explaining differences in pesticide intensity with reference to socioeconomic, political economic,
and agroecological characteristics and relationships. Using ordinary least squares regression models, this paper explores
the factors that influence pesticide use intensity in potato and squash production. Results indicate that many variables strongly
influence pesticide intensity, including variables related to the farmer, farm household, political-economic relationships,
the biophysical environment, and agroecological relationships. Conclusions discuss the need for an integrated approach to
adequately understand pesticide intensity and potential policy interventions including agroecological education and extension,
increased enforcement of pesticide residue limits in the national market, and land reform to allow for longer fallow periods.
相似文献
Ryan E. GaltEmail: |
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10.
Event-related brain potentials (ERP) are important neural correlates of cognitive processes. In the domain of language processing,
the N400 and P600 reflect lexical-semantic integration and syntactic processing problems, respectively. We suggest an interpretation
of these markers in terms of dynamical system theory and present two nonlinear dynamical models for syntactic computations
where different processing strategies correspond to functionally different regions in the system’s phase space.
相似文献
Peter beim GrabenEmail: |
11.
We present two computational models (i) long-range horizontal connections and the nonlinear effect in V1 and (ii) the filling-in
process at the blind spot. Both models are obtained deductively from standard regularization theory to show that physiological
evidence of V1 and V2 neural properties is essential for efficient image processing. We stress that the engineering approach
should be imported to understand visual systems computationally, even though this approach usually ignores physiological evidence
and the target is neither neurons nor the brain.
相似文献
Shunji SatohEmail: |
12.
13.
The design of a novel context-aware policy model to support machine-based learning and reasoning 总被引:1,自引:0,他引:1
John Strassner José Neuman de Souza David Raymer Srini Samudrala Steven Davy Keara Barrett 《Cluster computing》2009,12(1):17-43
The purpose of autonomic networking is to manage the business and technical complexity of networked components and systems.
However, the lack of a common lingua franca makes it impossible to use vendor-specific network management data to ascertain the state of the network at any given time.
Furthermore, the tools used to analyze management data are all different, and hence require different data in different formats.
This complicates the construction of context from diverse information sources. This paper describes a new version of the DEN-ng
context-aware policy model, which is part of the FOCALE autonomic network architecture. This model has been built using three
guiding principles: (1) both the context model and the policy model are rooted in information models, so that they can govern
managed entities, (2) each model is expressly constructed to facilitate the generation of ontologies, so that reasoning about
policies constructed from the model may be done, and (3) the model is expressly constructed so that a policy language that
supports machine-based reasoning and learning can be developed from it.
相似文献
Keara BarrettEmail: |
14.
Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
相似文献
Peter Godfrey-SmithEmail: |
15.
The Cauchy problem for one-dimensional spiking neuron models 总被引:1,自引:1,他引:0
Romain Brette 《Cognitive neurodynamics》2008,2(1):21-27
I consider spiking neuron models defined by a one-dimensional differential equation and a reset—i.e., neuron models of the
integrate-and-fire type. I address the question of the existence and uniqueness of a solution on for a given initial condition. It turns out that the reset introduces a countable and ordered set of backward solutions for
a given initial condition. I discuss the implications of these mathematical results in terms of neural coding and spike timing
precision.
相似文献
Romain BretteEmail: |
16.
The recent contribution by Jarmila Kukalová-Peck on Hennigian phylogenetics and hexapod limb evolution is critically evaluated.
相似文献
Michael S. Engel (Corresponding author)Email: |
17.
Susan Charnley Rebecca J. McLain Ellen M. Donoghue 《Human ecology: an interdisciplinary journal》2008,36(5):743-761
This paper examines the relation between public land management policy, amenity migration, and socioeconomic well-being using
the case of the Northwest Forest Plan—a forest management policy that caused 11.6 million acres of federal land in the US
Pacific Northwest to be reallocated from commodity production to biodiversity services. Our analysis focuses on three propositions
implicit in much of the amenity migration literature in the USA: land management policies that reduce commodity production
and/or increase environmental protection (1) improve the natural amenity values of public lands; (2) increase amenity migration
to communities near public lands; and (3) stimulate economic development and increase socioeconomic well-being in these communities.
Our findings indicate that all three propositions are problematic and demonstrate the importance of community-scale analysis
for understanding the relation between land management policies, amenity migration, and community well-being. We discuss the
implications of our findings for public land management and rural community development.
相似文献
Ellen M. DonoghueEmail: |
18.
Douglas Medin Norbert Ross Douglas Cox Scott Atran 《Human ecology: an interdisciplinary journal》2007,35(3):315-329
There is a continuing controversy over Native American fishing and hunting rights. We show that Native American (Menominee)
and European American fish experts have a common knowledge base and share values and attitudes associated with fishing practices
(though organized around different ethical principles). Nonetheless, perceived group differences are dramatic (especially European American perceptions of Native Americans). Cultural differences in models
of nature and associated inference processes appear to mediate these stereotypes and may hold the key to reducing intergroup
conflict over resources.
相似文献
Douglas MedinEmail: |
19.
Sahotra Sarkar 《Biology & philosophy》2008,23(2):217-228
On the basis of distinctions between those properties of entities that can be defined without reference to other entities
and those that (in different ways) cannot, this note argues that non-trivial forms of frequency-dependent selection of entities
should be interpreted as selection occurring at a level higher than that of those entities. It points out that, except in
degenerately simple cases, evolutionary game-theoretic models of selection are not models of individual selection. Similarly,
models of genotypic selection such as heterosis cannot be legitimately interpreted as models of genic selection. The analysis
presented here supports the views that: (i) selection should be viewed as a multi-level process; (ii) upper-level selection
is ubiquitous; (iii) kin selection should be viewed as a type of group selection rather than individual selection; and (iv)
inclusive fitness is not an individual property.
相似文献
Sahotra SarkarEmail: |
20.
Debates over adaptationism can be clarified and partially resolved by careful consideration of the ‘grain’ at which evolutionary
processes are described. The framework of ‘adaptive landscapes’ can be used to illustrate and facilitate this investigation.
We argue that natural selection may have special status at an intermediate grain of analysis of evolutionary processes. The
cases of sickle-cell disease and genomic imprinting are used as case studies.
相似文献
Peter Godfrey-SmithEmail: |