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81.
This article assesses the City of Montréal's éco-quartier program from the viewpoint of managing the urban environment and improving living environments. It evaluates the actual achievements of the program, looking especially at the ability of local communities to take effective action to improve their living environments, while under the guidance of the associations mandated to manage the program at the local level. Our research concentrated on three main areas: a) the development of the City of Montréal's environmental program; b) the effectiveness of the éco-quartiers in carrying out their mandate; c) the actual impacts of the program in improving living environments.  相似文献   
82.
ABSTRACT: Data from 56 north-temperate lakes and reservoirs are used to develop models predicting temporal variance as a function of the mean chlorophyll-a concentration. Trophy, as estimated by mean chlorophyll-a concentration, is shown to have little effect on the sampling effort required to achieve a pre-determined level of precision for lakes sampled year-round. Collecting ten observations results in a coefficient of variation that averaged 20 percent; collecting more than ten observations yields increasingly marginal improvements in precision. The same guidelines apply to mesotrophic or eutrophic lakes sampled in the summer, whereas oligotrophic lakes sampled in the summer require fewer observations to achieve the same level of precision. The bias resulting from collecting too few observations is minimized if five or more observations are collected.  相似文献   
83.
This paper presents the quantitative results of recent research on Canada's minerals and metals industry, and its international competitiveness for mineral investment. The information and analysis presented are derived from the work of a Canadian government-industry task force that was created in 1991, under the auspices of the Intergovernmental Working Group on the Mineral Industry (IGWG). Much of this work deals with mining taxation in several Canadian provinces. More importantly, an attempt is made to evaluate the total tax burden that the mining industry must bear, on a project basis, at all levels from exploration through refining operations in many important competitor countries. While the focus of the paper is on an international comparison of mining taxation, some non-tax issues relating to Canada's competitiveness for mineral investment are addressed .  相似文献   
84.
Field investigations were conducted to measure subsoil trace element content and factors influencing content in an intensive periurban market garden in Chenggong County, Yunnan Province, South-West China. The area was divided into three di erent geomorphological units: specifically, mountain (M), transition (T) and lacustrine (L). Mean trace element content in subsoil were determined for Pb (58.2 mg/kg), Cd (0.89 mg/kg), Cu (129.2 mg/kg), and Zn (97.0 mg/kg). Strong significant relationships between trace element content in topsoil and subsoil were observed. Both Pb and Zn were accumulated in topsoil (RTS (ratio of mean trace element in topsoil to subsoil) of Pb and Zn >1.0) and Cd and Cu in subsoil (RTS of Cd and Cu 61.0). Subsoil trace element content was related to relief, stoniness, soil color, clay content, and cation exchange capacity. Except for 7.5 YR (yellow-red) color, trace element content increased with color intensity from brown to reddish brown. Significant positive relationships were observed between Fe content and that of Pb and Cu. Trace element content in mountain unit subsoil was higher than in transition and lacustrine units (M > T > L), except for Cu (T > M > L). Mean trace element content in calcareous subsoil was higher than in sandstone and shale. Mean trace element content in clay texture subsoil was higher than in sandy and sandy loam subsoil, and higher Cu and Zn content in subsoil with few mottles. It is possible to model Pb, Cd, Cu, and Zn distribution in subsoil physico-chemical characteristics to help improve agricultural practice.  相似文献   
85.
The regulatory contribution that preferential trade agreements (PTAs) make to global climate governance is assessed through an analysis of climate-related provisions found in 688 PTAs signed between 1947 and 2016. Provisions are analyzed along four dimensions: innovation, legalization, replication, and distribution. Innovative climate provisions are found in several PTAs that are in some cases more specific and enforceable than the Kyoto Protocol and the Paris Agreement. Nonetheless, these climate provisions offer limited progress because they remain weakly ‘legalized’, fail to replicate broadly in the global trade system, and were not adopted by the largest greenhouse gas emitters. Despite the inclusion of innovative climate provisions in a number of PTAs, their poor design and weak replication position them as some of the weakest environmental provisions within PTAs.  相似文献   
86.
Between the early 1900s and the 1990s, the greater snow goose Anser caerulescens atlanticus population grew from 3000 individuals to more than 700 000. Because of concerns about Arctic degradation of natural habitats through overgrazing, a working group recommended the stabilization of the population. Declared overabundant in 1998, special management actions were then implemented in Canada and the United States. Meanwhile, a cost–benefit socioeconomic analysis was performed to set a target population size. Discussions aiming towards attaining a common vision were undertaken with stakeholders at multiple levels. The implemented measures have had varying success; but population size has been generally stable since 1999. To be effective and meet social acceptance, management actions must have a scientific basis, result from a consensus among stakeholders, and include an efficient monitoring programme. In this paper, historical changes in population size and management decisions along with past and current challenges encountered are discussed.  相似文献   
87.
We are interested in the impact of pollution permits on wages and profits. We analyze important consequences of introducing a market of pollution permits. A fundamental issue concerns the initial allocation of such permits: should they be allocated freely by grandfathering or be auctioned. The international symmetric case allows us to capture the essence of the problem on income factor. We show that allocating permits to factors in proportion of their contribution to production leads to an efficient (neoclassical) distribution. Considering the international asymmetric case, we show that a permit market does not modify the competitive world equilibrium without permits when the total allocation is large enough. When it is not, if allocation of permits is not proportional to the emissions in the world without permits, there is a reduction factor of emissions that results from the equilibrium allocation of capital.  相似文献   
88.
Scientific findings from the last decades have clearly highlighted the need for a more comprehensive approach to atmospheric change processes. In fact, observation of atmospheric composition variables has been an important activity of atmospheric research that has developed instrumental tools (advanced analytical techniques) and platforms (instrumented passenger aircrafts, ground-based in situ and remote sensing stations, earth observation satellite instruments) providing essential information on the composition of the atmosphere. The variability of the atmospheric system and the extreme complexity of the atmospheric cycles for short-lived gaseous and aerosol species have led to the development of complex models to interpret observations, test our theoretical understanding of atmospheric chemistry and predict future atmospheric composition. The validation of numerical models requires accurate information concerning the variability of atmospheric composition for targeted species via comparison with observations and measurements.In this paper, we provide an overview of recent advances in instrumentation and methodologies for measuring atmospheric composition changes from space, aircraft and the surface as well as recent improvements in laboratory techniques that permitted scientific advance in the field of atmospheric chemistry. Emphasis is given to the most promising and innovative technologies that will become operational in the near future to improve knowledge of atmospheric composition. Our current observation capacity, however, is not satisfactory to understand and predict future atmospheric composition changes, in relation to predicted climate warming. Based on the limitation of the current European observing system, we address the major gaps in a second part of the paper to explain why further developments in current observation strategies are still needed to strengthen and optimise an observing system not only capable of responding to the requirements of atmospheric services but also to newly open scientific questions.  相似文献   
89.
90.
1,2,5,6-Tetrabromocyclooctane (TBCO) is a commercial brominated flame retardant that is employed mainly as an additive in textiles, paints and plastics. Very little is known about its presence or behavior in the environment or its analysis. TBCO can exist as two diastereomers, the stereochemistries of which have not been previously reported. We have named the first eluting isomer, under HPLC conditions, as alpha-TBCO (α-TBCO) and the later eluting isomer as beta-TBCO (β-TBCO) when using an Acquity UPLC BEH C18 column with methanol/acetonitrile/water as the mobile phase. The structural elucidation of these two isomers was accomplished by 1H NMR spectroscopy, GC/MS, LC/MS and X-ray structure determinations. α-TBCO is (1R,2R,5S,6S)-1,2,5,6-tetrabromocyclooctane and β-TBCO is rac-(1R,2R,5R,6R)-1,2,5,6-tetrabromocyclooctane. As with some other brominated cycloaliphatic compounds, TBCO is thermally labile and the isomers easily interconvert. A thermal equilibrium mixture of α- and β-TBCO consists of approximately 15% and 85% of these isomers, respectively. Separation of the two diastereomers, with minimal thermal interconversion between them, is achievable by careful selection of GC-capillary column length and injector temperature. LC/MS analyses of TBCO also presents an analytical challenge due to poor resolution of the isomers on chromatographic stationary phases, and weak intensity of molecular ions (or major fragment ions) when using LC-ESI/MS. Only bromide ions were seen in the mass spectra. APCI and APPI also failed to produce the molecular ion with sufficient intensity for identification.  相似文献   
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