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951.
Comparative overview of indoor air quality in Antwerp, Belgium   总被引:2,自引:0,他引:2  
This comprehensive study, a first in Belgium, aimed at characterizing the residential and school indoor air quality of subgroups that took part in the European Community Respiratory Health Survey and the International Study of Asthma and Allergy in Childhood [Masoli M, Fabian D, Holt S, Beasley R. Global Burden of Asthma, Medical Research Institute of New Zealand, University of Southampton; 2004.] questionnaire-based asthma and related illnesses studies. The principal aim was to perform a base-line study to assess the indoor air quality in Antwerp in terms of various gaseous and particulate pollutants. Secondly, it aimed to establish correlations between these pollutants investigated, the pollutant levels in the indoor and outdoor micro-environments, findings of the previous questionnaire-based studies and an epidemiological study which ran in conjunction with this study. Lastly, these results were compared and evaluated with current indoor and ambient guidelines in various countries This paper presents selected results on PM1, PM2.5 and PM10 mass concentrations and elemental C estimates as black smoke, as well as gaseous NO(2), SO(2), O(3) and BTEX concentrations of 18 residences and 27 schools. These are related to current guidelines of Flanders, Germany, Norway, China and Canada and evaluated with reference to selected similar studies. It was found that indoor sources such as tobacco smoking and carpets, the latter causing re-suspension of dust, are responsible for elevated indoor respirable particulate matter and place school children and residents at risk. Both PM2.5 and PM10 equalled or exceeded the current guidelines adopted by Flanders, noting that 12-h and 24-h PM2.5 were compared with an annual limit value. Indoor and ambient NO(2) concentrations in the school campaign were higher than the annual EU ambient norm. The other studied pollutant levels were below the current guidelines.  相似文献   
952.
Since 2005, excavations at Mare aux Songes, Mauritius, have revealed the presence of a very rich, ∼4,200-year-old fossil bone bed including dodo (Raphus cucullatus) bones and bone fragments. The recently excavated dodo assemblage comprises at least 17 individuals and is characterised by the presence of small and fragile skeletal elements, a dominance of leg elements and an absence of juveniles. The hydrology of the area suggests that dodos, like many other species, were probably lured to Mare aux Songes by the presence of freshwater during times of drought. The most likely scenario for the origin of the fossil deposit is that animals became trapped in the sediment in repeated miring events, which would favour the conservation of hindlimbs. Such a scenario is fully in accordance with the taphonomic characteristics of the bone assemblage.  相似文献   
953.
A methodology for eco-efficiency reporting is proposed with eco-efficiency indicators for climate change, acidification, photo-oxidant formation, human toxicity, freshwater aquatic ecotoxicity, eutrophication, energy consumption and waste generation. The method is applied to emission, consumption and production data of the Flemish industry provided by the Flemish environmental agency for the period 1995–2006. For climate change, acidification, photo-oxidant formation, human toxicity, freshwater aquatic ecotoxicity and eutrophication, the eco-efficiency improved by 39, 55, 41, 58, 72 and 53%, respectively. For each of these impact categories, the total environmental impact decreased despite an increase in production, indicating absolute decoupling of environmental impact from economic growth. The eco-efficiency indicator for energy consumption and waste generation improved by 16 and 14%, respectively. However, due to the increase in production, the total energy consumption and the amount of waste generated increased: for these two environmental themes decoupling from economic growth was relative. Despite the improved eco-efficiency, industry remains one of the main polluters in Flanders. The application of the method to emission, energy consumption and production data of the Flemish industry resulted in a comprehensive and correct source of information for the general public and the government. Moreover, it can serve as a basis for economically and environmentally sound decisions and for the evaluation of the impact of former decisions.  相似文献   
954.
In a context of continued environmental degradation of agricultural landscapes, the concept of Payments for Ecosystem Services (PES) has been attracting growing attention in both academic and policy circles. The main premise of this conservation approach is appealing: land users, who tend to be poorly, if at all, motivated to protect nature on their land, may be encouraged to do so through direct payments from ecosystem service buyers. The theoretical underpinnings of PES emanate from an environmental externality framework, in which market failures are considered the root cause of environmental degradation. While the PES concept is attractive at first sight, this article discusses some weaknesses in its conceptual foundation. It focuses on two important aspects of the market-based PES concept: the hidden political ambiguities of the externality framework and the risk that PES, especially if user-funded, may perpetuate and deepen the regressive financing of global commons by poor local communities.  相似文献   
955.
956.
Following a global trend, the new policy goals emphasize the need to protect rather than to use the ability of ecosystems to recover from disturbances. This necessitates the adoption of response measurements to quantify ecological condition and monitor ecological change. Response monitoring focuses on properties that are essential to the sustainability of the ecosystem. These monitoring tools can be used to establish natural ranges of ecological change within ecosystems, as well as to quantify conceptually acceptable and unacceptable ranges of change. Through a framework of biological criteria and biological impairment standards, the results of response monitoring can become an integral part of future water resource management strategies in South Africa.  相似文献   
957.
Debate on the relationship between diversity and stability has been driven by the recognition that species loss may influence ecosystem properties and processes. We conducted a litterbag experiment in the Scottish Highlands, United Kingdom, to examine the effects of altering plant litter diversity on decomposition, microbial biomass, and microfaunal abundance. The design of treatments was fully factorial and included five species from an upland plant community (silver birch, Betula pendula; Scots' pine, Pinus sylvestris; heather, Calluna vulgaris; bilberry, Vaccinium myrtillus; wavy-hair grass, Deschampsia flexuosa); species richness ranged from one to five species. We tested the effects of litter species richness and composition on variable means, whether increasing litter species richness reduced variability in the decomposer system, and whether any richness-variability relationships were maintained over time (196 vs. 564 days). While litter species composition effects controlled variable means, we revealed reductions in variability with increasing litter species richness, even after accounting for differences between litter types. These findings suggest that higher plant species richness per se may result in more stable ecosystem processes (e.g., decomposition) and decomposer communities. Negative richness-variation relationships generally relaxed over time, presumably because properties of litter mixtures became more homogeneous. However, given that plant litter inputs continue to enter the belowground system over time, we conclude that variation in ecosystem properties may be buffered by greater litter species richness.  相似文献   
958.
Planktonic developing organisms are generally assumed to be good dispersers showing little genetic structuring in neutral markers. At first glance, this also applies to the planktonic developing periwinkle Tectarius striatus, an endemic gastropod from Macaronesia (i.e. Azores, Madeira, Canary Islands and Cape Verde Islands), where the only sign of genetic structuring hitherto is provided by a non-significant allozyme/RAPD heterogeneity between the Cape Verde Islands and the other archipelagos. However, partial sequences of the mitochondrial cytochrome b and cytochrome oxidase I genes now show that the Cape Verde Islands and the three other archipelagos have no haplotypes in common, whereas the latter three do share several haplotypes. Nevertheless, this highly disjunct haplotype distribution does not entail a phylogeographic break separating the haplotypes of both areas in two reciprocally monophyletic groups. This remarkable geographic and phylogenetic structuring may be explained by assuming that T. striatus colonized the Macaronesian archipelagos in periods when sea levels were lower (and/or volcanic activity was higher), so that seamounts peaked above sea level and could act as stepping-stones. Yet, after the last glacial period seamounts submerged, thus preventing further stepping-stones mediated dispersal of T. striatus between the Cape Verde Islands and the other archipelagos, while not affecting dispersal among the latter because of their closer proximity and connectivity. Hence, these contrasting patterns of neutral genetic variation in T. striatus show that genetic structuring in planktonic developing species may be far more complex than is usually assumed.  相似文献   
959.
Close associations between adult males and lactating females and their dependent infants are not commonly described in non-monogamous mammals. However, such associations [sometimes called “friendships” (Smuts 1985)] are regularly observed in several primate species in which females mate with multiple males during the fertile period. The absence of mating exclusivity among “friends” suggests that males should invest little in infant care, raising questions about the adaptive significance of friendship bonds. Using data from genetic paternity analyses, patterns of behavior, and long-term demographic and reproductive records, we evaluated the extent to which friendships in four multi-male, multi-female yellow baboon (Papio cynocephalus) groups in Amboseli, Kenya represent joint parental care of offspring or male mating effort. We found evidence that mothers and infants benefited directly from friendships; friendships provided mother–infant dyads protection from harassment from other adult and immature females. In addition, nearly half of all male friends were the genetic fathers of offspring and had been observed mating with mothers during the days of most likely conception for those offspring. In contrast, nearly all friends who were not fathers were also not observed to consort with the mother during the days of most likely conception, suggesting that friendships between mothers and non-fathers did not result from paternity confusion. Finally, we found no evidence that prior friendship increased a male’s chances of mating with a female in future reproductive cycles. Our results suggest that, for many male–female pairs at Amboseli, friendships represented a form of biparental care of offspring. Males in the remaining friendship dyads may be trading protection of infants in exchange for some resources or services not yet identified. Our study is the first to find evidence that female primates gain social benefits from their early associations with adult males. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
960.
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