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781.
AbstractThis paper addresses the relevance of the demand side for the achievement of sustainable transport in urban areas. The underlying thesis is that a better understanding of user habits, perceptions and attitudes with its specific dynamics is essential for a successful design of targeted transport policies. In line with this, the paper at hand is based on research that aims at improving the knowledge of urban-transport-related habits and attitudes of young adults. The results of three interview meetings that were held in Karlsruhe, Budapest, and Copenhagen with participants aged between 20 and 30 are presented. Background of the interviews is a range of studies that indicate that young people in urban areas seem to be less interested in cars than the generation before. And indeed, the interview meetings reveal that participants had a rather pragmatic attitude towards transport modes. They wished a transport system that is flexible, convenient and cheap. Despite many differences, most participants showed rather positive attitudes towards policies supporting alternatives to car-based transport. However, it will be crucial for policy shaping to what extent the observed behaviour patterns and attitudes will persist over time. 相似文献
782.
Paul Braunger Hermann Frank Christian Korunka Manfred Lueger Bettina Kubicek 《International journal of occupational safety and ergonomics》2013,19(1):143-155
This paper attempts to replicate a safety climate model originally tested in Australia to assess its applicability in a different context: namely, across production workers in 22 medium-sized metal processing organizations in Austria. The model postulates that safety knowledge and safety motivation mediate the relation between safety climate on the one hand and safety compliance and participation on the other. Self-report data from 1075 employees were analyzed using structural equation modeling (SEM). The results of the replication study largely confirmed the original safety climate model. However, in addition to indirect effects, direct links between safety climate and actual safety behavior were found. 相似文献
783.
The chloroplast gene rbcL was sequenced to elucidate the evolution of the gymnosperm plant order Cycadales. In accordance with traditional systematics, the order Cycadales and the corresponding genera cluster as monophyletic clades. Among them, the genus Cycas forms a basal group. The genetic distances within the genus Encephalartos and between the sister groups Encephalartos, Lepidozamia and Macrozamia, are unexpectedly small, suggesting that the extant species are the result of Miocene and Pliocene speciation. Their distribution in Africa or Australia, respectively, may therefore rather be due to long-distance dispersal than to Cretaceous continental drift, as had previously been assumed. The rbcL sequences also indicate that the colonisation of Madagascar by Cycas thouarsii occurred only recently as the sequences of C. thouarsii and Cycas rumphii from Indonesia are identical. In contrast, the divergence of the Cycadaceae and Zamiaceae apparently occurred in the Mesozoic. 相似文献
784.
The muricid Thais distinguenda (ca. 1,300 individuals) was collected from a pristine island in the Andaman Sea and tagged prior to translocation to an area of intense shipping activities. A minimum of 50 tagged individuals were recaptured 1, 2, 3, 5, 6, 7, 8 and 12 months after transplantation. The animals were separated into small (< or = 25 mm) and big (>25 mm) specimens based on total shell length and both incidence of imposex and body burden of butyltin (BT) were determined. After 3 months 16.7% of the small size and none of the big size class had developed imposex. After 5 months the incidence of imposex in the big and small size classes increased steadily with time reaching 86.4 and 80%, respectively after 1 year. Time after transplantation was significantly correlated with the incidence of imposex for the big size class (Spearman Rs=1; P=0.008); RPLI (Spearman Rs=1; P=0.008) and VDSI (Spearman Rs=1; P=0.008); and the small size class: incidence of imposex (Spearman Rs=1; P=0.006); RPLI (Spearman Rs=1; P=0.006) and VDSI (Spearman Rs=1: P=0.007). The development of imposex was not significantly related to body size after five months (chi square P<0.001). The body burden of tributyltin was not significantly different between the two size classes (paired t-test ) but the smaller animals had significantly higher concentrations of both dibutyltin (DBT; P<0.005) and monobutyltin (MBT; P<0.001). The use of transplantation experiments in addition to imposex surveys and analysis of body burden of tributyltin (TBT) can enhance the interpretation of the results and understanding of the time scale involved with the development of imposex. 相似文献
785.
Jens Frahm 《Die Naturwissenschaften》1987,74(9):415-422
Nuclear magnetic resonance (NMR) spectroscopy and imaging provide new tools for non-invasive investigations of living systems. Recent developments in rapid NMR imaging now offer considerable improvements for both scientific applications and medical diagnosis. Using fast imaging sequences cross-sectional images may be recorded within seconds and, therefore, become free from motional artifacts due to breathing or peristalsis. New functional imaging experiments include dynamic studies of the application of paramagnetic contrast agents or ECG-synchronized recordings of cardiac NMR movies. Superior anatomical information is achieved by three-dimensional NMR imaging with measuring times of minutes rather than hours. 相似文献
786.
787.
Peter Schröder Lyudmila Lyubenova Christian Huber 《Environmental science and pollution research international》2009,16(7):795-804
Background, aim and scope
Mixed pollution with trace elements and organic industrial compounds is characteristic for many spill areas and dumping sites. The danger for the environment and human health from such sites is large, and sustainable remediation strategies are urgently needed. Phytoremediation seems to be a cheap and environmentally sound option for the removal of unwanted compounds, and the hyperaccumulation of trace elements and toxic metals is seemingly independent from the metabolism of organic xenobiotics. However, stress reactions, ROS formation and depletion of antioxidants will also cause alterations in xenobiotic detoxification. Here, we investigate the capability of plants to detoxify chlorophenols via glutathione conjugation in a mixed pollution situation. 相似文献788.
Degradation and mobility of the surfactants linear alkylbenzene sulfonate (LAS) and nonylphenol (NP) were investigated in a lysimeter study using a sandy loam soil and 45-cm soil columns. Anaerobically digested sewage sludge was incorporated in the top-15-cm soil layer to an initial content of 38 mg LAS and 0.56 mg NP kg(-1) dry wt., respectively. Spring barley (Hordeum vulgare L.) was sown onto the columns. The lysimeters were placed outdoors and therefore received natural precipitation, but were also irrigated to a total amount of water equivalent to 700 mm of precipitation. Leachate and soil samples from three soil layers were collected continuously during a growth period of 110 d. Leachate samples and soil extracts were concentrated by solid-phase extraction (SPE) and analyzed using high performance liquid chromatography (HPLC) with fluorescence detection. The concentrations in the top-15-cm soil layer declined to 25 and 45% of the initial contents for LAS and NP, respectively, within the first 10 d of the study. At the end of the study, less than 1% LAS was left, while the NP content was below the detection limit. Assuming first-order degradation kinetics, half-lives of 20 and 37 d were estimated for LAS and NP, respectively. The surfactants were not measured in leachate samples in concentrations above the analytical detection limits of 4.0 and 0.5 microg L(-1) for LAS and NP, respectively. In addition, neither LAS nor NP were measured in concentrations above the detection limits of 150 and 50 microg kg(-1) dry wt., respectively, in soil layers below the 15 cm of sludge incorporation, indicating negligible downward transport of the surfactants in the lysimeters. 相似文献
789.
790.
According to outdated paradigms humic substances (HS) are considered to be refractory or inert that do not directly interact with aquatic organisms. However, they are taken up and induce biotransformation activities and may act as hormone-like substances. In the present study, we tested whether HS can interfere with endocrine regulation in the amphibian Xenopus laevis. In order to exclude contamination with phyto-hormones, which may occur in environmental isolates, the artificial HS1500 was applied. The in vivo results showed that HS1500 causes significant estrogenic effects on X. laevis during its larval development and results of semi-quantitative RT-PCR revealed a marked increase of the estrogenic biomarker estrogen receptor mRNA (ER-mRNA). Furthermore, preliminary RT-PCR results showed that the thyroid-stimulating hormone (TSHbeta-mRNA) is enhanced after exposure to HS1500, indicating a weak adverse effect on T3/T4 availability. Hence, HS may have estrogenic and anti-thyroidal effects on aquatic animals, and therefore may influence the structure of aquatic communities and they may be considered environmental signaling chemicals. 相似文献