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11.
The Barents Sea is among the most productive areas in the world oceans, and its shallow banks exhibit particularly high rates of primary productivity reaching over 300 g C m?2year?1. Our study focused on the Svalbard Bank, an important feeding area for fishes and whales. In order to investigate how benthic community structure and benthic secondary production vary across environmental gradients and through time, we sampled across the bank and compared results with a similar study conducted 85 years ago. Considerable variability in community structure and function across bank corresponded with differences in the physical structure of the habitat, including currents, sedimentation regimes and sediment type, and overlying water masses. Despite an intensive scallop fishery and climatic shifts that have taken place since the last survey in the 1920s, benthic community structure was very similar to that from the previous survey, suggesting strong system resilience. Primary and secondary production over shallow banks plays a large role in the Barents Sea and may act as a carbon subsidy to surrounding fish populations, of which many are of commercial importance.  相似文献   
12.
In the course of researches into radon occurrence in the groundwaters of the Polish part of the Sudety Mountains, conducted in various research centres in Poland, almost 1000 radon concentration determinations have been collected. These results have given the basis for an attempt to characterise the groundwaters of this region with respect to radon content. Radon concentrations oscillated within the range of 0.2-1645 Bq/dm3, with the arithmetic mean at 240.0 Bq/dm3 and the geometric mean at 106.7 Bq/dm3. The largest number of radon concentrations found in the Sudetic groundwaters ranged between ca. 3-6 and 1000 Bq/dm3. The values over 1000 Bq/dm3 can be considered anomalously high. They constitute 3.9% of all the results and occur around six localities within different geological units of the Sudety Mountains. These are shallow circulation, low mineralised groundwaters, which outflow from gneisses and granites. In the face of the fact that from 12.8% to 72.7% (depending on the adopted norm of maximum radon concentration for drinking waters) of the examined waters cannot be drunk directly without removing at least part of the radon, and in the face of the possibility of recognizing as many as 63.5% of the waters as potentially medicinal, extensive research of radon geochemistry in the Sudety Mountains area should be urgently undertaken.  相似文献   
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Summary. Females of the forest cockchafer, Melolontha hippocastani Fabr. (Coleoptera: Scarabaeidae, Melolonthinae), are known to produce toluquinone and 1,4-benzoquinone. The latter component has been shown in our earlier studies to act as a sex attractant that enhances synergistically the attraction of males towards plant volatiles induced by feeding females. Analyses of whole body extracts from adults and grubs (L3) of M. hippocastani by coupled gas chromatography--mass spectrometry revealed the presence of 1,4-benzoquinone and toluquinone also in males and larvae. Quantitative analyses showed that extracts from females contained significantly more of 1,4-benzoquinone and toluquinone than extracts from males. Remarkably, extracts from grubs contained significantly higher amounts of both compounds than extracts from females. Inhibition assays using Escherichia coli, Saccharomyces cerevisiae, and the entomopathogenic fungi Metarhizium anisopliae and Beauveria brongniartii revealed inhibitory effects of 1,4-benzoquinone and toluquinone against all tested microorganisms. However, the amounts necessary for inhibition of entomopathogenic fungi and S. cerevisiae in the laboratory assay were higher than those found in the extracts from M. hippocastani.  相似文献   
15.
A European standard for the determination of Cr(vi) in solid material has been elaborated in the framework of an international co-operation and finally validated in the course of an interlaboratory comparison. The procedure is based on the alkaline digestion prescribed by EPA method 3060A followed by ion chromatography and determines an operationally defined content of Cr(vi), including water-soluble and insoluble chromates. A preliminary robustness study was carried out in order to compare different extraction methodologies and to study the equivalency of different analytical methods for the determination of Cr(vi) in alkaline extracts of soil and waste materials. During an interlaboratory validation trial with 19 European laboratories a set of 4 samples (2 soil and 2 waste samples) was analysed to determine performance characteristics for different combinations of digestion and detection methods. With the procedures prescribed by the new European standard (EN 15192) acceptable results were obtained for both soil samples and one of the waste samples (sludge). However, for the second waste sample (fly ash) a large deviation in analytical results was observed. This indicates that particularly for waste materials a possible occurrence of strong matrix effects has to be considered and supplementary quality control data are needed in order to assess the validity of analytical results. The accuracy of the determination of Cr(vi) in solid matrices remains a challenging field in terms of maximum extraction efficiency and minimum species interconversion.  相似文献   
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The aim of the study was to evaluate the possibility of supplementation with inorganic forms of selenium (Na2SeO4 and Na2SeO3) in concentrations of 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 and 1.5 mM of three medicinal mushroom species: Agrocybe aegerita, Hericium erinaceus and Ganoderma lucidum. Tested mushroom species grew in Se additions of 0–0.6 mM (A. aegerita and H. erinaceus), while growth of G. lucidum bodies was observed for 0–0.8 mM. For the latter mushroom species, the total Se content was the highest. Content of Seorg was diverse; for control bodies it was the highest for G. lucidum (only organic forms were present), lower for A. aegerita (84% organic forms) and the lowest for H. erinaceus (56% organic forms). Accumulation of Se(IV) was generally significantly higher than Se(VI) for all tested mushroom species. There was no significant decrease of A. aegerita or G. lucidum biomass with the exception of G. lucidum bodies growing under 0.8 mM of Se species addition (15.51 ± 6.53 g). Biomass of H. erinaceus bodies was the highest under 0.2 (197.04 ± 8.73 g), control (191.80 ± 6.06 g) and 0.1 mM (185.04 ± 8.73 g) of both inorganic salts. The addition to the medium of Se salts brought about macroscopic changes in the fruiting bodies of the examined mushrooms. Concentrations exceeding 0.4 mM caused diminution of carpophores or even their total absence. In addition, colour changes of fruiting bodies were also recorded. At Se concentrations of 0.4 and 0.6 mM, A. aegerita fruiting bodies were distinctly lighter and those of H. erinaceus changed colour from purely white to white-pink.  相似文献   
18.
A laboratory experiment was performed to examine the remobilization of indicator polychlorinated biphenyls (iPCBs) from sediments and its results were applied to the real-world data for explaining the transport of PCBs in river. Seven PCB concentrations were determined in three series of model water–sediment systems (3 g of river sediment, three different volumes of distilled water (0.5, 0.25, and 0.15 ml), and 5 mg of biocide) after 11 days of incubation. Solid-phase extraction was used for separation of analytes from the aqueous phase and solvent extraction for isolation of analytes from the sediments, respectively. The extracts were analyzed for individual iPCB congeners using gas chromatography–mass spectrometry method. For each series of the experiment, the concentrations of PCBs in aqueous phase were similar. The average sediment/water partition coefficient value was 104?l/kg. The solubility of individual PCB congeners in water did not influence the desorption of PCBs from the sediment. Although the dominant form of PCBs in a water–sediment system occurs as suspended and colloidal fractions, these compounds are transported mostly in a dissolved form. Suspended and colloidal matter is a major sink for PCBs in low-energy aquatic environments. In contrast, the dissolved PCBs are readily transported in running waters. The mobilization of PCBs from sediments to aqueous phase, with respect to their solubility in water, seems to be limited, thus reducing the risk of secondary pollution.  相似文献   
19.
Temporal and spatial patterns of micropollutants in urban receiving waters   总被引:1,自引:0,他引:1  
Based on a monitoring program over the course of a year, we characterize the temporal and spatial distribution of selected micropollutants in an urban watershed within the city of Leipzig, Germany. Micropollutants revealed a ubiquitous presence in untreated and treated wastewater, surface water and groundwater. The loads of 4-nonylphenol in the effluents of the municipal wastewater treatment plant followed a seasonal trend, whereas the loads of all other micropollutants were highly variable and not correlated to seasons. In the surface water, load seasonality of caffeine, galaxolide and tonalide resulted from a rapid removal with increased water temperature. The loads of 4-nonylphenol and of caffeine in the colder months increased when rainfall occurred. In the groundwater, complex spatial and temporal patterns were apparent and were related to varying input, retardation and removal processes. As a consequence, an assessment of micropollutants in urban waters should consider different micropollutants' temporal and spatial variability.  相似文献   
20.
Genetic counseling for prenatal diagnosis of autosomal trisomy is complex because of the uncertainty of outcome, which is important for management decisions. Compilation of cases of prenatally diagnosed autosomal trisomies in amniocytes has been done previously in an attempt to elucidate the clinical phenotype of these pregnancies. It has been greater than a decade since these studies were completed. To update this work, we reviewed cases reported in the literature since that time. These cases are correlated with the prior reports to increase knowledge about outcomes and to hopefully improve the data available for genetic counseling. The risk of abnormal outcome can be summarized as: very high risk (>60%) for 47,+2/46; 47,+9/46; 47,+16/46; 47,+20/46; and 47,+22/46; high risk (40–59%) for 47,+5/46; 47,+14/46; and 47,+15/46; moderately high risk (20–39%) for 47,+7/46 47,+12/46; and 47,+17/46; moderate risk (up to 19%) for 47,+6/46 and 47,+8/46, and none were low risk. 47,+6/46 was originally indeterminate, 47,+7/46 was originally moderate risk, 47,+9/46 was originally high risk, and 47,+17/46 was originally low risk. © 2015 John Wiley & Sons, Ltd.  相似文献   
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