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81.
There are many cost-effective technologies to reduce resource use and carbon dioxide emissions in space heating, yet they are adopted very slowly, and inefficient heating systems persist. In this article, we examine path dependence and path creation in home heating systems. Path dependence refers to the self-sustaining characteristics of existing systems such as the dominant energy system. Path creation is a related concept that highlights entrepreneurship in ‘mindfully deviating’ from existing paths and creating new ones by engaging various stakeholders and generating momentum. Research on path creation in energy systems has focused on energy production systems, whereas end-use technologies have gained less attention. We explore the role of path creation in end-use technologies through four attempts to change heating systems for detached houses in Finland via the promotion of heat pump technologies. Within the path creation process, we focus on how the initiators of new paths try to counter the forces maintaining the dominant system. In particular, we pay attention to how small organizations make use of co-operation to challenge the existing path. The aim is to identify the conditions for successful path creation by entrepreneurs and energy end-users under adverse conditions.  相似文献   
82.
Surface marine sediments from Ría de Arousa estuary were analyzed for humic and fulvic acids by UV-visible spectrometry and have been characterized using elemental analysis (carbon, hydrogen and nitrogen elemental composition) and spectrometric data (A2/A4 ratio, absorbancies at 270 and 407 nm and E4/E6 ratio, absorbancies at 465 and 665 nm). These variables have been used as discriminating factors to distinguish of marine and terrestrial origin of humic and fulvic acids in Ría de Arousa surface marine sediments. Principal component analysis, PCA, and cluster analysis, CA, have been used as unsupervised pattern recognition procedures. The half-range central value transformation was used as data pre-treatment to homogenize data. After a Varimax rotation, PCA applied to humic acid data has reveled that spectrometric A2/A4 and E4/E6 ratios are the main dominating features in the first principal component (48.6% of total variance), the humic acid content is the feature with the highest weight in the second principal component (22.9% of the total variability) and the carbon elemental composition domain in the third principal component (13.3% of total variance). Results from PCA have revealed that surface sediments collected at inner-left part of the estuary and at the mouth of the river Ulla belong to the same group. Similarly, PCA has shown that surface sediments from the right mouth of the estuary form a compact group. Taking in account the water circulation in Ría de Arousa estuary, these findings mean that the organic matter in surface sediments from the inner-left part of the estuary derived mainly from terrestrial organic matter while the organic matter in surface sediments from the right mouth of the estuary is mainly derived from marine sources. Finally, it must be noticed that any classification of surface sediments was assessed when applying of PCA and CA from fulvic acids data.  相似文献   
83.
Particle emissions from residential wood combustion in small communities in Northern Sweden can sometimes increase the ambient particle concentrations to levels comparable to densely trafficked streets in the center of large cities. The reason for this is the combination of increased need for domestic heating during periods of low temperatures, leading to higher emission rates, and stable meteorological conditions. In this work, the authors compare two different approaches to quantify the wood combustion contribution to fine particles in Northern Sweden: a multivariate source-receptor analysis on inorganic compounds followed by multiple linear regression (MLR) of fine particle concentrations and levoglucosan used as a tracer. From the receptor model, it can be seen that residential wood combustion corresponds with 70% of modeled particle mass. Smaller contributions are also seen from local nonexhaust traffic particles, road dust, and brake wear (each contributing 14%). Of the mass, 1.5% is explained by long-distance transported particles, and 2% derives from a regional source deriving from either oil combustion or smelter activities. In samples collected in ambient air, a significant linear correlation was found between wood burning particles and levoglucosan. The levoglucosan fraction in the ambient fine particulate matter attributed to wood burning according to the multivariate analysis ranged from < 2% to 50%. This is much higher than the fraction found in the emission from the boilers expected to be responsible for most emissions at this site (between 3% and 6%). A laboratory emission study of wood and pellet boilers gave 0.3% wt to 22% wt levoglucosan to particle mass, indicating that the levoglucosan fraction may be highly dependent on combustion conditions, making it uncertain to use it as a quantitative tracer under real-world burning conditions. Thus, quantitative estimates of wood burning contributions will be very uncertain using solely levoglucosan as a tracer.  相似文献   
84.

Gene expression can be modified in people who are chronically exposed to high concentrations of heavy metals. The soil surrounding the Ventanas Industrial Complex, located on the coastal zone of Puchuncaví and Quintero townships (Chile), contain heavy metal concentrations (As, Cu, Pb, Zn, among others) that far exceed international standards. The aim of this study was to determine the potential association of the heavy metals in soils, especially arsenic, with the status of methylation of four tumor suppressor genes in permanent residents in those townships. To study the methylation status in genes p53, p16, APC, and RASSF1A, we took blood samples from adults living in areas near the industrial complex for at least 5 years and compared it to blood samples from adults living in areas with normal heavy metal concentrations of soils. Results indicated that inhabitants of an area with high levels of heavy metals in soil have a significantly higher proportion of methylation in the promoter region of the p53 tumor suppressor gene compared with control areas (p-value: 0.0035). This is the first study to consider associations between heavy metal exposure in humans and aberrant DNA methylation in Chile. Our results suggest more research to support consistent decision-making on processes of environmental remediation or prevention of exposure.

  相似文献   
85.
The influence of light on phytotoxicity of increased concentration (2, 5, 10 mg/l) of intact fluoranthene (FLT) and photomodified fluoranthene (phFLT) diluted in experimental solutions was investigated. The germination rate of lettuce (Lactuca sativa L.), onion (Allium cepa L.) and tomato (Lycopersicum esculentum L.) seeds and some parameters of seedlings primary growth of these plant species were used as laboratory indicators of phytotoxicity. Among them a length of root and shoot, their dry weight and a content of photosynthetic pigments in shoot were measured. The results demonstrated that the higher concentration (5 and 10 mg/l) of FLT and especially of phFLT significantly inhibited the germination rate of seeds and the length of root and shoot seedlings of all plant species. Decreased production of biomass expressed by dry weight of root and shoot was found in lettuce seedlings under the inhibitory effect of FLT and phFLT. An increased concentration of FLT and phFLT did not exhibit an unambiguous effect on the content of photosynthetic pigments in shoot of experimental plants. Only the highest concentration (10 mg/l) of FLT significantly increased content of chlorophylls a and b in lettuce, onion and tomato plants and content of carotenoids in lettuce and onion. Light intensified a significant inhibitory effect of phFLT in the most testified parameters of germination and seedling growth.  相似文献   
86.
The environmental occurrence of hexabromocyclododecane in Sweden   总被引:6,自引:0,他引:6  
The brominated flame retardant hexabromocyclododecane (HBCD) is extensively used in Europe, but data on the environmental concentrations of this chemical are scarce. A first screening has been performed concerning the environmental occurrence of HBCD in Sweden, a country where the chemical is not produced and the current industrial use is very limited. Possible emission sources were identified through a systematic analysis of the use in a life cycle perspective. In addition to a few point sources, diffuse emissions from polymeric products are possible. Measurements have been performed close to certain possible point sources, in the urban environment and in remote regions, and included air, deposition, water, soil, sediments, sludge, biota and foodstuffs. HBCD was detected in all media analysed and in all environments. The relatively high concentrations detected in herring and foodstuffs provide evidence for bioaccumulation of HBCD. The presence of HBCD in remote background air implies that HBCD has potential for long-range atmospheric transport. There are also some indications that diffuse emissions of HBCD occur in the urban environment.  相似文献   
87.
Establishment of Carex rostrata, Eriophorum angustifolium and Phragmites australis on weathered, acidic mine tailings (pH approximately 3) and their effect on pH in tailings were investigated in a field experiment. The amendments, sewage sludge and an ashes-sewage sludge mixture, were used as plant nutrition and their influence on the metal and As concentrations of plant shoots was analysed. An additional experiment was performed in greenhouse with E. angustifolium and sewage sludge as amendments in both weathered and unweathered tailings. After one year, plants grew better in amendments containing ashes in the field, also in those plants the metal and As shoot concentrations were generally lower than in other treatments. After two years, the only surviving plants were found in sewage sludge mixed with ashes. No effect on pH by plants was found in weathered acidic mine tailings in either field- or greenhouse experiment.  相似文献   
88.
- DOI: http://dx.doi.org/10.1065/espr2006.01.002 Background Davide Calamari and his colleagues were among the first to appreciate that vegetation could play a key role in determining the fate and effects of organic contaminants. They conducted pioneering experiments to investigate the uptake of contaminants by plants from the atmosphere and they sought to model the observed phenomena. In the nearly two decades since there has been a marked increase in understanding of these phenomena as a result of both experimental and modelling studies. - Goal. In this study we briefly review our current understanding of chemical partitioning between foliage and air. A model in both fugacity and concentration format is described, based on that of Tolls and McLachlan (1994), in which the leaf is treated as consisting of two layers, a waxy cuticle with an underlying 'reservoir' layer, the cuticle being surrounded by an air boundary layer and containing stomata that provide direct access from the air to the 'reservoir'. The model quantifies the dynamic penetration of a defined chemical into a defined leaf as a function of time. Main Features The model is applied for illustrative purposes to a hypothetical but typical leaf for a set of illustrative chemicals to demonstrate the effect of changes in physical-chemical properties and leaf characteristics. Discussion The results are compared qualitatively with a variety of field and laboratory studies of foliage uptake and clearance of chemicals. Conclusion It is concluded that the model yields results that are generally consistent with observations. It is suggested that with appropriate parameterisation and validation, the model can contribute to an improved understanding of the process of foliage uptake from the atmosphere and to the development of an improved predictive capability.  相似文献   
89.
Environmental Science and Pollution Research - At the global scale, urban agriculture is increasingly developing in cities due to demographic growth and sustainable food concerns. But, urban soils...  相似文献   
90.
Birds are important components of biodiversity conservation since they are capable of indicating changes in the general status of wildlife and of the countryside. The Pan-European Common Bird Monitoring Scheme (PECBM) has been launched by the BirdLife Partnership in Europe, where the European Bird Census Council has been collecting data from 20 independent breeding bird survey programs across Europe over the last 25 years. These data show dramatic declines in European farmland birds. We suggest that seasonal characteristics of vegetation cover derived from high temporal resolution remote sensing images could facilitate the monitoring the suitability of farmland bird habitats, and that these indicators may be a better choice for monitoring than climate data. We used redundancy analysis to link the PECBM data of the estimated number of farmland birds in Europe to a set of phenological and climatic indicators and to the biogeographic regions of Europe. Variance partitioning was used to account for the variation explained by the phenological and climate variables and by the area of the environmental strata individually, to define the pure effect of the variables, and to extract the total explained variance. The analysis revealed high statistical significance (p < 0.001) of the correlations between species and environment. Phenological indices explained 38% of the variance in community composition of the 23 farmland bird species, whereas climate explained 30% of the variance. After partitioning the other variables as covariables, the pure effect of phenology, climate, and environmental strata were 16%, 8%, and 16%, respectively. Based on the probability results, we suggest that phenological indicators derived from remote sensing may supply better indicators for continental scale biodiversity studies than climate only. In addition, these indicators are cost and time effective, are on continuous scale, and are readily repeatable on a large spatial coverage while supplying standardized results.  相似文献   
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