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981.
Ester van der Voet Reinout Heijungs Paul Mulder Ruben Huele René Kleijn Lauran van Oers 《Environmental science and pollution research international》1995,2(3):137-144
In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes: (1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement measures. Each application has its own requirements with regard to data and modelling. 相似文献
982.
Ester van der Voet René Kleijn Lauran van Oers Reinout Heijungs Ruben Huele Paul Mulder 《Environmental science and pollution research international》1997,4(2):112-112
Part I: Abstract In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method is presented. SFA
aims at providing the relevant information for a country’s overall management strategy regarding single substances or coherent
groups of substances. This article is dedicated to the presentation of a threestep general framework for SFA-type studies,
and elaborates on its first step the systems definition. Attention is given to the definition of the external and internal
system boundaries, the categorization of the system’s elements, aspects of materials choice, time, and space, and how these
depend on the aim of the conducted study. Moreover, a broader discussion is started on the need for standardization of materials
flow studies in general.
Part II: Abstract In the tradition of the study of materials flows through society, the Substance Flow Analysis (SFA) method and its software
tool SFINX are presented. SFA aims at providing the relevant information for a country’s overall management strategy regarding
single substances or coherent groups of substances. Three modelling techniques and their possibilities and limitations are
discussed: Bookkeeping, static modelling, and dynamic modelling. The computer program SFINX can be used for varoius purposes:
(1) to obtain an overview of stocks and flows of a substance in, out and through a nation’s economy and environment for a
specific year, (2) to trace the origins of specific pollution problems, and (3) to estimate the effectiveness of certain abatement
measures. Each application has its own requirements with regard to data and modelling. 相似文献
983.
Spatial and seasonal variation in heavy metals in interstitial water of salt marsh soils 总被引:2,自引:0,他引:2
The composition of interstitial water collected from a salt marsh in NW Spain showed clear seasonal and spatial variations associated with redox cycles of Fe and S. In the summer, salinity increased in all soils as a consequence of the increase in evapotranspiration. The pH and concentrations of heavy metals also differed with season, but not all environments showed the same variations. Soils not colonized by plants had the highest pH and lowest heavy metal concentrations in the summer. These results support the idea that higher temperatures lead to an increase in the activity of sulfate-reducing bacteria, which in turn leads to an increase in alkalinity and concentration of sulfides in the water. Trace metals tend to precipitate with sulfides under these conditions and are removed from the interstitial water. In contrast, in the soils colonized by Spartina maritima, the oxidation of metal sulfides during the summer led to a decrease in pH and an increase in the metal concentrations in the interstitial water. The results obtained concur with those found for seasonal variations in metal sulfides in soils from the same salt marsh. 相似文献
984.
Durana N Navazo M Alonso L García JA Ilardia JL Gómez MC Gangoiti G 《Journal of the Air & Waste Management Association (1995)》2002,52(10):1176-1185
This paper presents results of the processing and validation of data collected by an automatic gas chromatograph (AGC). This system was used to monitor 62 volatile organic compounds (VOCs) in urban air in the Basque Country, Spain. The nonpolar compounds (C2-C10) identified-paraffins, olefins, aromatics, and chlorinated compounds-accounted for 88% of the mass of total non-methane hydrocarbons (TNMHCs) in ambient air. The evaluation of linearity, precision, detection limits (DLs), and stability of retention times (RTs) indicates that the equipment is suitable for measuring ambient air automatically for prolonged periods (6 months). The calibration of the equipment using response factors calculated on the basis of the effective carbon number (ECN) showed variations of over 10% for acetylene, isoprene, and n-hexane. The results provided by the automatic chromatograph correlated significantly with simultaneous results from other widely used techniques for determining VOCs in ambient air: (1) portable GC, equipped with photoionization detector (PID), and (2) active adsorption on Tenax-TA followed by thermal desorption and chromatographic analysis. 相似文献
985.
El Bakouri H Palacios-Santander JM Cubillana-Aguilera L Ouassini A Naranjo-Rodríguez I Hidalgo-Hidalgo de Cisneros JL 《Chemosphere》2005,60(11):1565-1571
Successful applications of different analytical procedures to determine quantitatively endosulfan and its metabolites in aqueous media can be found in recent literature. Fundamentally, they have made use of solid-phase extraction (SPE) and gas (GC) or liquid chromatography (LC), sometimes coupled to mass spectrometry (MS). In this paper, a new and alternative methodology to determine quantitatively endosulfan in aqueous media is reported. A C18-modified carbon-paste electrode has been used to determine voltammetrically endosulfan, despite its unfavourable electrochemical properties and behaviour. The methodology proposed is based on the decrease experienced by the peak intensity corresponding to voltammetric signals of Cu(II) when successive and constant additions of endosulfan are carried out. This decrease is directly proportional to the concentration of endosulfan what allows to perform an indirect quantification of the pesticide. The detection limit obtained is 40 ng l−1, this value being under the limits specified by European norms and EPA reports. 相似文献
986.
Dinel H Schnitzer M Saharinen M Meloche F Paré T Dumontet S Lemee L Ambles A 《Journal of environmental science and health. Part. B》2003,38(2):211-219
Pyrolysis-gas (Py-GC) chromatography was used to characterize extractable lipids from Bt and non-Bt maize shoots and soils collected at time of harvesting. Py-GC-MS (mass spectrometry) showed that the concentrations of total alkenes identified in non-Bt shoots and soils were 47.9 and 21.3% higher than in Bt maize shoots and soils, respectively. N-alkanes identified were of similar orders of magnitude in Bt and non-Bt maize shoots, but were 28.6% higher in Bt than in non-Bt soils. Bt maize shoots contained 29.7% more n-fatty acids than non-Bt maize shoots, whereas the concentrations of n-fatty acids in Bt soils were twice as high as those in non-Bt soils. Concentrations of unsaturated fatty acids in Bt maize shoots were 22.1% higher than those in non-Bt maize shoots, while concentrations of unsaturated fatty acids were 22.5% higher in non-Bt than in Bt soils. The cumulative CO2-C evolved from soils under Bt and non-Bt crops was 30.5% lower under Bt as compared to non-Bt crops, whereas when maize shoots were added to Bt and non-Bt soils, the decrease in CO2-C evolved were 16.5 and 23.6%, respectively. Our data showed that the cultivation of Bt maize significantly increased the saturated to unsaturated lipid ratios in soils which appeared to negatively affect microbial activity. 相似文献
987.
Jos Harmsen 《生态毒理学报》2000,22(2):35-36
1999年7月,喀麦隆的一个小农合作社Macefcoop成功地将其头两集装箱有机咖啡装运到欧洲.这是从非洲进入"公平交易"市场的第一种有机咖啡. 相似文献
988.
989.
Daniela Canestrari José M. Marcos Vittorio Baglione 《Behavioral ecology and sociobiology》2005,57(5):422-428
Carrion crows Corvus corone corone in northern Spain form complex cooperative groups that contain non-dispersing offspring and immigrants. Reproduction is often shared among group members, with polyandry prevalent over joint egg laying. However, due to incest avoidance or sexual immaturity, reproduction is potentially available only to a fraction of group members (potential breeders), while others do not breed (non-breeders). We combined molecular data with video-recorded observations at nests in order to investigate whether potential breeders and non-breeders adjust their individual effort in nestling feeding respectively to their level of parentage and the relatedness with the chicks. Overall, parents of at least one chick in the brood showed the highest feeding rates. Among potential breeders, genetic mothers and fathers fed chicks at significantly higher rates than individuals with no parentage, but they did not adjust their effort according to the proportion of offspring generated. Current direct fitness benefits are therefore important in determining a high provisioning effort, but crows may lack a mechanism to finely assess their share of parentage. Among non-breeders, males contributed more than females to chick feeding, but we found no significant correlation between feeding rate and relatedness to the nestling. We discuss how the latter result can be reconciled with the fact that kin selection has been shown to be important in shaping the crow cooperative society.Communicated by C. Brown 相似文献
990.
Patrice Lucchetta Emmanuel Desouhant Eric Wajnberg Carlos Bernstein 《Behavioral ecology and sociobiology》2007,61(9):1409-1418
The reproductive success of insect parasitoids depends on two activities, searching for hosts to obtain immediate fitness
rewards (offspring) and searching for food to extend life span and enhance future reproductive opportunities. Models suggest
that to deal with this trade-off and to cope with the variability of the resources they depend on, parasitoids should simultaneously
integrate information originating from three distinct sources: host and food availabilities in the environment (environmental
information) and the metabolic reserves of the parasitoid (internal information). We tested whether, in the parasitic wasp
Venturia canescens, these three types of information are perceived simultaneously and interact during host-patch exploitation. Experiments were
performed with strains originating from two different geographical locations and with individuals of the two reproductive
modes, arrhenotoky and thelytoky. We hypothesised that there would be differences between modes of reproduction as they thrive
in different ecological conditions. Our results show that metabolic state, food availability and the number of ovipositions
performed simultaneously modulate patch residence time in V. canescens of both populations and reproductive modes. Unfed wasps left their host patch earlier than fed ones. The tendency to leave
the patch increased with an increasing probability of finding food. Our study confirms that globally, each oviposition increases
the patch-leaving tendency (decremental mechanism). This effect was modulated by both the metabolic reserves and food availability,
and the relationship depended on the geographic origin of populations. Individuals of one of the populations switched from
a decremental to an incremental patch-leaving mechanism depending on the presence or absence of food in the vicinity. Differences
between reproductive modes in the responses to environmental cues can be explained by the different ecological conditions
they live in. 相似文献