排序方式: 共有9条查询结果,搜索用时 31 毫秒
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Catherine Potvin Petra Tschakert Frédéric Lebel Kate Kirby Hector Barrios Judith Bocariza Jaime Caisamo Leonel Caisamo Charianito Cansari Juan Casamá Maribel Casamá Laura Chamorra Nesar Dumasa Shira Goldenberg Villalaz Guainora Patrick Hayes Tim Moore Johana Ruíz 《Mitigation and Adaptation Strategies for Global Change》2007,12(8):1341-1362
This paper is part of a two-year study to investigate the feasibility of initiating a Clean Development Mechanism (CDM) project
in an indigenous community of Eastern Panamá, Ipetí-Emberá. We use participatory mapping and matrices as well as household
surveys to develop a land-use/land-cover baseline scenario and examine the role of local participation in assessing land-use
change. In Ipetí, land-use change has not occurred in a linear way over the last decades, and our data unveils socio-economic
factors as potential key drivers of change. The concordance that we observed between geographic information and individual
and collective perceptions of land-use change substantiates the possibility of using local knowledge in the establishment
of baseline data for CDM projects. Our calculations suggest that the total carbon (C) stocks in the Tierra Colectiva (TC) of Ipetí-Emberá in 2004 represents a 47% reduction from the estimated C stock at the onset of settlement in the early
1970’s. Results from the participatory assessments predict that, in 2024 and in absence of a CDM project, the C stocks will
decline from 301,859 t C in 2004 to 155,730 t C, which constitutes a reduction of 52%. The scenario with CDM estimates C stocks
of 305,853 t C for 2024, a value slightly superior to the 2004 value. In the TC there is ground to believe that cattle ranching
is likely to become an ever more important activity as the population is young and growing and cannot easily move elsewhere.
Forests tend to be cleared for cultivation while pastures are established on short fallows. Our baseline scenario underlines
the potential for a CDM project to make a significant difference in the future C stocks of this landscape. 相似文献
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Principal Component Analysis (PCA) is a convenient tool used in aggregating the indicators of sustainable development and providing indices where different weights are assigned to the various indicators. There are, however, problems in interpreting of indices, especially if time series data are used. This study explores the feasibility of applying recent developments in PCA of time series using Philippine data. We present the comparative advantages of SPCA (Sparse Principal Component Analysis) relative to averaging of an adequacy/inadequacy index and PCA in index construction from various indicators of sustainable development in the Philippines in terms of usefulness and validity of indices being developed. SPCA can attain sparse and non-overlapping loadings without losing a large amount of explained variance compared to PCA. Because of the non-overlapping contribution of variables in SPCA components, indices can have clear and mutually exclusive meanings, facilitating interpretation. Even with a more complicated algorithm, reduced dimensions and simpler interpretation of indices justify the advantages of SPCA over PCA in index construction. The indices are interpreted in terms of the milestone of sustainability in the Philippines. The resulting indices provide an adequate summary of the sustainable indicators and evidence of the importance of leadership and political will in sustainable development. 相似文献
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Juan José Benvenuta Tapia Martin Hernández Valdez Jorge Cerna Cortez Víctor Martin Díaz García Heber Landeros Barrios 《Journal of Polymers and the Environment》2018,26(11):4221-4232
In this work, a series of reactive copolymers of glycidyl methacrylate (G), styrene (S) and acrylonitrile (AN), were synthesized through reversible addition-fragmentation chain transfer polymerization and evaluated as macromolecular chain extenders in reactive extrusion of recycled poly(ethylene terephthalate) (rPET). The results obtained indicate that the addition of the reactive copolymers as chain extenders modifies the chain conformation in rPET causing low crystallization rate and low crystallinity. The physical and rheological properties (melt flow and intrinsic viscosity) of chain-extended rPET improved, rendering better processability. rPET modified with polymeric chain extenders shows improved rheological properties (complex viscosity, storage and loss modulus) and also displays higher elongation at break and impact properties as the GMA content in the chain extenders increase. 相似文献
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Xu Q Barrios CA Cutright T Newby BM 《Environmental science and pollution research international》2005,12(5):278-284
- Goal, Scope, Background. The traditional solution for keeping unwanted organisms from attaching to submerged surfaces is to
apply anti-fouling coatings. The most common antifoulant was tributyltin (TBT). TBT systems were highly effective but were
also toxic to non-target organisms. The use of the TBT based coatings will be completely banned by January 1, 2008. Therefore,
there is an urgent need to seek out suitable non-toxic alternatives.
Methods The aim of this work was to evaluate the effectiveness of capsaicin and zosteric acid as natural product antifoulants (NPAs)
in deterring bacterial attachment. Two fresh water bacteria systems Pseudomonas putida (Pp) and bacteria isolated from Lake
Erie (LE) were used to assess the attachment when the NPAs dispersed in the water. Effectiveness was ascertained based on
the decrease in microbial attachment, limited toxicity, and minimum alteration of the coatings properties.
Results and Discussion A significant inhibition of bacteria attachment was achieved when aqueous capsaicin concentration was increased from 0 to
40 mg/L. For instance, after 14 days the LE system depicted 93.5% and 98.5% less biofilm coverage for 20 mg/L and 40 mg/L
capsaicin, respectively when compared to systems without NPA. Biofilm coverage was reduced by 92.5% and 98.2%, respectively
with 50 mg/L and 500 mg/L zosteric acid.
Conclusions Both capsaicin and zosteric acid was effective at preventing bacteria attachment. As the NPA aqueous concentration increased,
biofilm formation decreased. Evaluating changes in aqueous pH, conductivity, dissolved oxygen, aqueous microbial population
and biofilm formation suggested that the primary antifoulant mechanism of these two NPAs was to block the bacteria's active
sites versus posing a lethal level.
Recommendation and Perspective From the attachment study, zosteric acid appeared to be more effective in preventing bacterial attachment when the NPAs were
dispersed in the aqueous environment. For practical applications, the antifoulant needs to be incorporated into a coating
and have a slow release rate. Thus the ability to successfully incorporate zosteric acid into a coating, without deterring
bacterial attachment, needs to be investigated. 相似文献
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Monitoring agricultural sustainability requires careful summarising of indicators collected over time into indices representing facets of sustainability. When the number of variables exceeds the number of observations, interpretation of components from ordinary principal component analysis is usually difficult because of minimal or absence of sparsity among the loadings. This is also true for time series indicators that exhibit non-stationarity. A framework for the assessment of agricultural sustainability in a regional context is proposed. Sparse principal component analysis is used in constructing indices of agricultural sustainability that are then used to characterise the state of agricultural development and the dynamics of agricultural growth in Southeast Asia. 相似文献
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In situ stabilization of toxic elements in contaminated soils by the addition of amendments is being considered as an effective technique for remediation. In this paper, we performed both kinetics and equilibrium-based sorption experiments of three toxic elements (As, Cd and Tl) in soils amended with two by-products (phosphogypsum and sugar foam, rich in gypsum and calcium carbonate, respectively) to ascertain the feasibility of their application for improving the sorption capacity of As, Cd and Tl from the soil at 25, 35 and 50 °C. Kinetic studies indicated that the sorption follows a pseudo-second-order (PSO) kinetics and the sorption is a two-step diffusion process where both film and intraparticle diffusion played important roles in the sorption mechanisms of the elements. The Langmuir isotherms applied for sorption studies showed that the estimated maximum sorption capacity of the elements in control and amended soils decreased in the order of Cd > As > Tl. Using the thermodynamic equilibrium parameters obtained at different temperatures, the thermodynamic constants of sorption (ΔG, ΔH and ΔS) were also evaluated, indicating spontaneous and endothermic nature of the process, except Tl which was exothermic. An optimal scaling procedure was undertaken to determine the relationships between the kinetic and equilibrium sorption parameters. By means of statistical analysis it was seen that these inter-parametric relationships are dependent on the element nature. 相似文献
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Roberto E. Barrios 《Disasters》2014,38(2):329-350
A number of recent studies on disaster reconstruction have focused on the concept of community resilience and its importance in the recovery of communities from collective trauma. This article reviews the contributions the anthropological literature and the ethnographic case studies of two post‐Hurricane Mitch housing reconstruction sites make to the theorising of community and resilience in post‐disaster reconstruction. Specifically, the article demonstrates that communities are not static or neatly bounded entities that remain constant before, during and after a disaster; rather, communities take on shape and qualities depending on the relationships in which they engage with government agencies and aid organisations before and after disasters. Consequently, the article argues that definitions of community resilience and disaster mitigation programmes must take the emergent and relational nature of communities into account in order to address the long‐term causes and impacts of disasters. 相似文献
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