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121.
The composition and abundance of marine biota in Israeli marine ecosystems are affected by natural and anthropogenic pressures, including blooms of non-indigenous jellyfish and overfishing. While overfishing is itself a major stressor of fish stocks, it appears that jellyfish may be outcompeting fish for scarce planktonic food resources. Beyond this direct impact on fisheries, jellyfish–ecosystem interactions are also important because of the disturbance they cause to multiple users of marine and coastal resources. This paper documents the concurrent changes in the composition of marine biotic communities, including jellyfish proliferation and dwindling stocks of endemic, commercially valuable fish and the rising rate of bottom trawling in Israeli fisheries. The capacity to deal directly with jellyfish is limited by lack of knowledge about their ecology. Therefore, we suggest that bolstering fish stocks and increasing their competitive advantage in the food web may be instrumental in limiting jellyfish blooms. Coordination of fishing and conservation policies is recommended, as are modifications to marine waste management and deployment of submerged artificial substrates.  相似文献   
122.
The fate and transport of antibiotics in natural water systems is controlled in part by interactions with nanometer (10−9 m) metal oxide particles. Experiments were performed by mixing solutions of ampicillin (AMP), a common, penicillin-class human and veterinary antibiotic, with 25 nm-TiO2 (anatase) nanoparticles at different pH conditions. Both sorption and degradation of AMP were observed in the AMP-nanoparticle solutions. For AMP concentrations from ∼3 μM to 2.9 mM the overall AMP removal from solution can be described by linear isotherms with removal coefficients (Kr) of 3028 (±267) L kg−1 at pH 2, 11,533 (±823) L kg−1 at pH 4, 12,712 (±672) L kg−1 at pH 6, and 1941 (±342) L kg−1 at pH 8. Mass spectral analysis of AMP solutions after removal of the solid nanoparticles yielded ions that indicate the presence of peniclloic acid, penilloic acid and related de-ammoniated by-products as possible compounds resulting from the degradation of AMP at the TiO2 surface.  相似文献   
123.
This paper discusses monitoring the waste destruction efficiency of hazardous waste incinerators. The particular problem is to ensure that incinerators do not release, without detection, significant quantities of waste as a result of operating fluctuations or equipment degradation. To detect these conditions, continuous, automated, and real-time source monitoring is required. Detection of degraded performance by monitoring and measuring waste compounds directly is not presently possible on a continuous basis. An alternative is to use commercially available continuous monitors to measure combustion intermediates (e.g., CO or hydrocarbons) and thereby infer waste destruction efficiency. Required, however, is a correlation between the emission of intermediates and the emission of waste. In this paper, the response of a number of these continuous monitors is compared with waste destruction efficiency measurements from a laboratory scale, liquid-spray incinerator operated on fuel oil doped with model waste compounds: benzene, chlorobenzene, acrylonitrile, and chloroform. Total hydrocarbon and CH4 measurements are found to vary with waste emission in a nearly linear manner; however, a substantial increase in CO emission occurs before a significant amount of waste is released. These results suggest that CO may serve as an indicator of the approach of waste release, while total hydrocarbons may provide an indicator of immediate waste release.  相似文献   
124.
This paper focuses on the influence of the current density treatment of a concentrated 1-butyl-3-methylimidazolium chloride (BMImCl) solution on an electrochemical reactor with a boron-doped diamond (BDD) anode. The decrease in the total organic carbon (TOC) and the BMImCl concentration demonstrate the capability of BDD in oxidizing ionic liquids (ILs) and further mineralizing (to CO2 and NO3 ?) more rapidly at higher current densities in spite of the reduced current efficiency of the process. Moreover, the presence of Cl? led to the formation of oxychlorinated anions (mostly ClO3 ? and ClO4 ?) and, in combination with the ammonia generated in the cathode from the nitrate reduction, chloramines, more intensely at higher current density. Finally, the analysis of the intermediates formed revealed no apparent influence of the current density on the BMImCl degradation mechanism. The current density presents therefore a complex influence on the IL treatment process that is discussed throughout this paper.  相似文献   
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126.
A novel microbial source tracking (MST) method based on the detection of human and non-human markers was developed and applied to track the origin of fecal pollution in water systems. Mitochondrial DNA sequences were used to develop new quantitative real-time polymerase chain reaction (qPCR) assays for dog, poultry, and gull. The targets were included as part of a toolbox including human, cow, pig, and sheep assays. A primer and probe set for the detection of the human-specific nifH gene of Methanobrevibacter smithii was also designed as an indicator of human fecal contamination. The assays were tested for specificity and applied to fecal-spiked surface waters and environmental samples collected from two river catchments impacted by sources of human and non-human fecal contamination. The MST methods described were applicable to both spiked waters and environmental samples, and using the two approaches the origin of fecal pollution could be successfully determined in mixed source fecally polluted waters.  相似文献   
127.
128.
We describe here the first case of neonatal death due to the hyperornithinaemia, hyperammonaemia, and homocitrullinuria (HHH) syndrome and the first prenatal diagnosis of this disorder in a subsequent pregnancy in this family.  相似文献   
129.
The association between gestational infection with human parvovirus (B19) and fetal loss has increased interest in this virus and demand for diagnostic testing. However, serological assays for B19 are not yet widely available. Maternal serum alpha-fetoprotein (MSAFP) testing is commonly used during the second trimester to screen for various fetal defects. We attempted to determine whether an elevated level of MSAFP would be an appropriate indication for B19-specific tests. Over a 26-month period, MSAFP tests were performed at Michigan State University for 21 392 women. Sera remaining after that testing were stored frozen. Of these, 22 case samples—from women with MSAFP levels greater than 3·0 multiples of the median (MOM) and pregnancies that ended in fetal loss—and 44 matched control samples—from women with MSAFP levels greater than 0·4 and less than 2·2 MOM and live births at term—were tested for B19 antibodies. None of the 66 samples was IgM positive, while 33 (50 per cent) were IgG positive. The presence of IgG was not significantly associated with case or control status (matched odds ratio=0·77, 95 per cent confidence interval 0·28–2·11). These findings are consistent with other studies indicating prior infection in approximately half of adults and suggest that elevated screening MSAFP levels, in the absence of other evidence of B19 infection, should not prompt B19-specific testing.  相似文献   
130.
We report our experience in ascertaining fetal triploidy during routine maternal serum alpha-fetoprotein (MSAFP) screening. Three cases were identified after elevated MSAFP tests. Two of the three had normal amniotic fluid alpha-fetoprotein (AFAFP). The third had amniocentesis too late for AFAFP interpretation. Three additional cases were detected by amniocentesis without prior MSAFP screening and none had an elevated AFAFP. A literature review revealed eight triploid fetuses detected as a result of an elevated MSAFP. Of the five with AFAFP quantitation, only one had an abnormal value and the elevation was minimal. In these 14 cases from our own and other reports, ultrasound findings of placental and fetal abnormalities were often noted, but a pattern diagnostic of triploidy was not present. We conclude that, for optimal prenatal detection of triploidy, fetal karyotyping should be included when an amniocentesis is performed for elevated MSAFP.  相似文献   
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