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41.
Pribylová P Klánová J Holoubek I 《Environmental pollution (Barking, Essex : 1987)》2006,144(1):248-254
Wide distribution of chlorinated paraffins in the environment has already been demonstrated in several studies; however, information about their levels in the Central Europe is still very limited. First study focused on the SCCP contamination of the Czech aquatic environment have been performed recently, and its results motivated the authors to analyze sediments from a wide set of the Czech rivers in order to obtain more detailed information. Thirty-six sediment samples from eleven rivers and five drainage vents neighboring the chemical factories were analyzed; special attention was paid to the industrial areas. For the first time in the Czech Republic, medium-chain in addition to short-chain chlorinated paraffins were analyzed using GC-ECNI-MS. Chlorinated paraffins were detected in sediment samples on the concentration levels up to 347 ngg(-1) for short-chain chlorinated paraffins, and 5575 ngg(-1) for medium-chain chlorinated paraffins. Average chlorination degree of SCCPs was 65%. 相似文献
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This study presents a meta-analysis of a collective dataset describing the succession from abandoned fields to semi-natural
grassland and heathland vegetation over the past century. The study objectives were to develop a method for statistical discrimination
between abandoned fields and semi-natural habitats and to analyze the probability that an abandoned field had developed into
a semi-natural habitat. A statistical classification model was developed, based on lists of vascular plants from 2059 plots
from Danish semi-natural grasslands and heathlands, and abandoned fields of varying age. This model was shown to discriminate
effectively between abandoned fields and semi-natural habitats, and it was found to be potentially useful for the detection
of abandoned fields approaching semi-natural vegetation. We suggest that the model may help clarify restoration targets and
assess biological condition in formerly cultivated areas. Statistical modeling revealed that succession age, period of abandonment
and succession trajectory had significant effects on the probability that abandoned fields reached the semi-natural phase.
Our study indicates that restoration projects targeting grassland and heathland should take local species pools and soil fertility
into account.
Nomenclature: Species names follow Flora Europaea (Tutin and others 1964–1993). 相似文献
44.
We are happy and proud to announce that our book ‘Atmospheric Degradation of Organic Substances — Data for Persistence and
Long-range Transport’ (see pp. 143–144) has recently been published by Wiley-VCH [1]. It contains a critical compilation of
photo degradation rate constants and quantum efficiencies relevant for calculating the atmospheric persistence of volatile
and a few semi-volatile organic compounds. In addition to the data of nearly 1100 substances, the importance of persistence
in air and long-range transport potential is presented in two chapters from the point of view of chemicals legislation and
of atmospheric photochemistry. 相似文献
45.
Mass spectrometry fingerprinting of humic acids extracted from different soils has been carried out using laser desorption/ionization mass spectrometry (LDI-TOF MS). LDI-TOF MS provides characteristic mass spectra fingerprints for the humic acids of different origin. The information given in the fingerprints was evaluated for natural grouping trends in the samples by neural networks computing tools, such as self-organizing feature map (SOFM). This approach is efficient for recognizing patterns in the humic acids samples independently of their characteristic variability; variability characterizing natural products such as humic substances. The use of multi-layer perceptron artificial neural networks gave a successful classification of the samples. 相似文献
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Maie Bachmann Ruth Tomson Jaan Kalda Maksim Säkki Jaanus Lass Viiu Tuulik Hiie Hinrikus 《The Environmentalist》2007,27(4):511-517
This study was aimed to investigate the changes in the human electroencephalographic (EEG) signal caused by modulated low-level
microwaves. The 450 MHz microwave exposure modulated at 40 Hz and 70 Hz frequencies was applied to a group of 15 volunteers.
The field power density at the scalp was 0.16 mW/cm2. Ten cycles of the exposure (1 min on and 1 min off) at both modulation frequencies were applied. Analysis of the EEG signal
was performed using three different methods: nonlinear method of scaling analysis for length distribution of low variability
periods (LDLVP), relative changes in EEG energy (S-parameter) and beta ratio (H-parameter). The analysis revealed significant changes caused by microwave for the whole group (H-parameter method). The exposure caused increase of the EEG beta power (S-parameter method). Statistically significant changes in EEG were detected for four subjects (26.7%) at 40 Hz modulation frequency
(LDLVP method). 相似文献
48.
Tommy Gärling Anita Svensson-Gärling Jaan Valsiner 《Journal of environmental psychology》1984,4(3):235-252
One hundred and five parents and nonparents responded to a questionnaire consisting of evaluative ratings (general evaluation, social status and safety concern) of six familiar residential neighborhoods; ratings of the traffic accident risk children in the age ranges 2–4, 5–6, 7–9 and 10–12 years run in these neighborhoods; and, finally, ratings of the strengths attributed to factors as causes of traffic accidents (environment, children, parents, drivers and chance). Across neighborhoods and age ranges of children, risk perceptions were found to be related to the rated strengths of the causes. Low-traffic volume neighborhoods were perceived as less risky and were attributed as less strong causes than high-traffic volume neighborhoods were. Perceived risk increased with age of child to a maximum, then decreased. The same relationship with age was found for the attributed causes environment and drivers. The strength of parents as cause was rated to decrease while the strength of child as cause was rated to increase with age. Chance was rated as the weakest cause and the rated strength did not vary across neighborhoods or age. Neither parentship nor gender, singly or in combination, had any clear effects. For parents and nonparents alike the general evaluation of the neighborhoods was influenced by safety concern but not by the particular aspect investigated, i.e. perceived traffic accident risk to children. 相似文献
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