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991.
Two different strategies aiming at increasing household source-separation of food waste were assessed through a case-study in a Swedish residential area (a) use of written information, distributed as leaflets amongst households and (b) installation of equipment for source-segregation of waste with the aim of increasing convenience food waste sorting in kitchens. Weightings of separately collected food waste before and after distribution of written information suggest that this resulted in neither a significant increased amount of separately collected food waste, nor an increased source-separation ratio. After installation of sorting equipment in households, both the amount of separately collected food waste as well as the source-separation ratio increased vastly. Long-term monitoring shows that results where longstanding. Results emphasize the importance of convenience and existence of infrastructure necessary for source-segregation of waste as important factors for household waste recycling, but also highlight the need of addressing these aspects where waste is generated, i.e. already inside the household.  相似文献   
992.
Two-year old Ulmus laevis Pall (U. laevis) seedlings were cultivated in a three-month hydroponic experiment with inorganic (aresenite – As(III) and arsenate – As(V)) and organic (dimethylarsenic acid – DMA(V)) arsenic forms, at 0.06 and/or 0.6?mM concentrations. Further, the profile and content of total low molecular weight organic acids (LMWOAs) were investigated in the rhizosphere, roots and leaves of U. laevis. Obtained results showed that the addition of As(III) or As(V) individually or in a mixture led to increased LMWOAs concentration in the rhizosphere, especially of oxalic and malonic acids, in comparison to the control, while in roots the overall content of the profiled LMWOAs decreased. In both rhizosphere and roots, addition of the DMA(V) form resulted in the inhibition of LMWOAs exudation into the rhizosphere and their creation in plant roots. Leaves were characterised by a higher content of LMWOAs than in the rhizosphere and roots for all experimental systems, where the profile and content of LMWOAs was strictly correlated with the analysed As forms. Our study indicated that creation of LMWOAs in U. laevis organs and their exudation to the rhizosphere could be responsible for the As toxicity tolerance of the plants.  相似文献   
993.
994.
Biosynthetic studies on marking pheromones of bumblebee males   总被引:2,自引:0,他引:2  
Summary. The biosynthetic pathway of the formation of males'marking pheromones of two bumblebee species, Bombus lucorum and B.lapidarius, was studied for the first time. After applications ofdeuterium labelled palmitic acid ([2H31]-hexadecanoic acid) into eitherthe head capsules or abdomens the corresponding deuterium labelledpheromone components were detected in the labial gland (LG) extracts ofmales of both species. In B. lucorum, ethyl [2H29]-hexadec-9-enoate andethyl [2H31]-hexadecanoate were identified. No deuterium-labelled ethyltetradecenoate, that would correspond to shortening of the carbon chain,was detected. In B. B. lapidarius, [2H31]-hexadecan-1-ol and[2H29]-hexadec-9-en-1-ol were found in the LG. Furthermore, thedeuterium labelled precursor was incorporated into triacylglycerols(TAG) of the fat bodies of males. In vitro incubation of the labialglands of B. lucorum males with deuterium-and 13C-labelled palmiticacid lead to the formation of saturated ethyl esters only.  相似文献   
995.
996.
The basic premise underlying the approach presented in the paper is the assumption that humans are unique beings that can evaluate. The environment is described as a system of resources satisfying human needs. The assessment of the effects of environmental pollution derives from the fact that there is, or will be, non-satisfaction of needs resulting from a reduction in environmental resources.  相似文献   
997.
A critical challenge in natural resource management is to bring all stakeholders together to negotiate solutions to critical problems. However, various collaborative approaches to heading off conflicts and resolving natural resource management disputes have been used. What drives these efforts, however, still needs further research. Our study provides a systematic look at the drivers likely to initiate collaborative problem-solving efforts in four cases in Romania. We use Emerson’s et al. (2012) framework for collaborative governance and multi-value qualitative comparative analysis (mvQCA) to analyze cases involving endangered species, restrictions on forest harvest, conflicts associated with infrastructure development projects, and disputes over the management of environmentally sensitive areas. Our findings contribute to the already existing collaborative governance literature indicating which of the four factors: uncertainty, interdependence, consequential incentives, and leadership, in which combination, are necessary and sufficient to spur collaborative resource management efforts. Our results showed that in Romania the initiation of collaboration is best explained by positive consequential incentives (i.e., financial opportunities) which has determined leaders to take initiative. This study provides additional information for the complicated process of natural resource management which is often overriding collaboration by investigating what enables and constrains collaborative efforts in a country where natural resources were managed and used according to the principles of central planning.  相似文献   
998.

Background and aim

Persistent organochlorine pollutants (POPs) have in epidemiological studies been associated with health hazards. The exposure window might be crucial and it is, accordingly, important to analyze exposure concentrations in samples collected at the window of interest. This makes the use of stored blood samples extremely interesting. However, small blood volumes from stored samples in biobanks means that the researchers in epidemiological studies most often have to select a limited number of biomarkers representing the POP exposure and abstain from analyses of lipid concentrations. This raises the question of the necessity of lipid adjustment. The aim of the present study was to evaluate the correlation between fresh weight and lipid adjusted concentrations.

Methods

We included data from studies were we have used the PCB congener 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153) as a biomarker for POP exposure and where fresh weight as well as lipid adjusted PCB-153 concentrations are known (n = 1628). The variety of the cohort members in the different studies gave us the possibility to better understand how well these measures correlate.

Results

When all individuals were included in the analyses a correlation coefficient of 0.95 between fresh weight and lipid adjusted serum concentrations was obtained. Restricting the analyses to specific subgroups (based on gender, fasting status, age and BMI) gave correlation coefficients between 0.85 and 0.97.

Conclusions

This study does strongly support the use of samples from biobanks in epidemiological studies for analyzing PCBs, at least regarding PCB-153, even though it is not possible to lipid adjust the results.  相似文献   
999.
Large herbivores play key roles in terrestrial ecosystems. Continuous defaunation processes have produced cascade effects on plant community composition, vegetation structure, and even climate. Wood-pastures were created by traditional management practices that have maintained open structures and biodiversity for millennia. In Europe, despite the broad recognition of their biological importance, such landscapes are declining due to land-use changes. This calls for finding urgent solutions for wood-pasture conservation. To test whether introducing an ecological replacement of an extinct wild horse could have positive effects on wood-pasture restoration, we designed a 3-year rewilding experiment. Horses created a more open wood-pasture structure by browsing on seedlings and saplings, affected tree composition via selective browsing and controlled the colonization of woody vegetation in grassland-dominated areas. Thus, rewilding could be a potential avenue for wood-pasture restoration and biodiversity conservation. However, such benefits may not materialize without a necessary paradigm and political shift.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01320-0) contains supplementary material, which is available to authorized users.  相似文献   
1000.
We present estimates of the vehicular contribution to ambient organic carbon (OC) and fine particle mass (PM) in Pittsburgh, PA using the chemical mass balance (CMB) model and a large dataset of ambient molecular marker concentrations. Source profiles for CMB analysis are selected using a method of comparing the ambient ratios of marker species with published profiles for gasoline and diesel vehicle emissions. The ambient wintertime data cluster on a hopanes/EC ratio–ratio plot, and therefore can be explained by a large number of different source profile combinations. In contrast, the widely varying summer ambient ratios can be explained by a more limited number of source profile combinations. We present results for a number of different CMB scenarios, all of which perform well on the different statistical tests used to establish the quality of a CMB solution. The results illustrate how CMB estimates depend critically on the marker-to-OC and marker-to-PM ratios of the source profiles. The vehicular contribution in the winter is bounded between 13% and 20% of the ambient OC (274±56–416±72 ng-C m−3). However, variability in the diesel profiles creates uncertainty in the gasoline–diesel split. On an OC basis, one set of scenarios suggests gasoline dominance, while a second set indicates a more even split. On a PM basis, all solutions indicate a diesel-dominated split. The summer CMB solutions do not present a consistent picture given the seasonal shift and wide variation in the ambient hopanes-to-EC ratios relative to the source profiles. If one set of source profiles is applied to the entire dataset, gasoline vehicles dominate vehicular OC in the winter but diesel dominates in the summer. The seasonal pattern in the ambient hopanes-to-EC ratios may be caused by photochemical decay of hopanes in the summer or by seasonal changes in vehicle emission profiles.  相似文献   
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