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71.
72.
In an effort to protect the quality of the water system, interest in non-point source pollution is increasing. Recently, studies of non-point sources pollution are continuing in relation to various land- use areas, but such studies have not been fully conducted in railway facility sites. Using monitoring data of railway bridge area with concrete road-bed, the runoff characteristics, pollutant unit loads, and first flush criteria were assessed. Railway bridge area with concrete road-bed typically show the first flush effect, and the pollutant unit load was determined to be higher than other public facilities areas. Further, the first flush criteria show an effective rainfall amount of 7 mm. In other words, from the runoff of railway facilities, considerable amounts of non-point source pollutants are occurred, indicating the need to create best management practices which are adequate for railway facility sites.  相似文献   
73.
The formulation of most pesticides is proprietary and individual components are therefore not generally known. In a preliminary study, we identified six compounds that are often present in pesticides, of which 4-nonylphenyl-polyethylene glycol(NP-40) was found to be the most toxic. In this study, we investigated the toxicity of NP-40 and underlying mechanism in neuronal SK-N-SH cells. Exposure to NP 40 at concentrations higher than60 μmol/L for 24 hr decreased cell viability. The cytotoxicity of NP-40 was time-and concentration-dependent. Nuclear fragmentation and chromatin condensation were apparent starting at 50 μmol/L NP-40, and increased at higher concentrations. The expression of apoptotic factors including p53 and B-cell lymphoma(Bcl)-2-associated X protein was upregulated, while that of the anti-apoptotic marker Bcl-2 was downregulated at 80 μmol/L NP-40. Cytochrome c release was observed from 80 to 100 μmol/L by confocal microscopy. Caspase-9 and-3/7 activities increased according to concentration, and fluorescence-activated cell sorting analysis showed that apoptosis was induced at50 μmol/L and was increased at 80 μmol/L. Our findings indicate that NP-40 stimulates the mitochondrial-mediated apoptosis pathway and reactive oxygen species production in a concentration-dependent manner, and suggest that antioxidant administration may be an effective treatment for patients with acute NP-40 poisoning.  相似文献   
74.
Photochemical aging of volatile organic compounds (VOCs) in the atmosphere is an important source of secondary organic aerosol (SOA). To evaluate the formation potential of SOA at an urban site in Lyon (France), an outdoor experiment using a Potential Aerosol Mass (PAM) oxidation flow reactor (OFR) was conducted throughout entire days during January-February 2017. Diurnal variation of SOA formations and their correlation with OH radical exposure (OHexp), ambient pollutants (VOCs and particulate matters, PM), Relative Humidity (RH), and temperature were explored in this study. Ambient urban air was exposed to high concentration of OH radicals with OHexp in range of (0.2–1.2)×1012 molecule/(cm3?sec), corresponding to several days to weeks of equivalent atmospheric photochemical aging. The results informed that urban air at Lyon has high potency to contribute to SOA, and these SOA productions were favored from OH radical photochemical oxidation rather than via ozonolysis. Maximum SOA formation (36 µg/m3) was obtained at OHexp of about 7.4 × 1011molecule/(cm3?sec), equivalent to approximately 5 days of atmospheric oxidation. The correlation between SOA formation and ambient environment conditions (RH & temperature, VOCs and PM) was observed. It was the first time to estimate SOA formation potential from ambient air over a long period in urban environment of Lyon.  相似文献   
75.
Environmental Science and Pollution Research - The main goal of this work was to produce an easily recoverable waste-based magnetic activated carbon (MAC) for an efficient removal of the...  相似文献   
76.
Practically no information exists on the impact of human trampling on tropical rain forest vegetation. We studied three trails with varying periods of use and recovery in a tropical rain forest in Costa Rica. Human impact on trailside plants was curvilinearly related to use, as found by other workers in temperate zone vegetation. Recovery in a period of two years and eight months had been rapid, and herbs and seedlings were more abundant along the recovering trail than in undisturbed forest. The results imply that a shifting mosaic of trails, analogous to the mosaic created by light gaps, may be the best management technique to minimize the impact of human visitors in tropical rain forests.  相似文献   
77.
Gil Luria 《组织行为杂志》2019,40(9-10):1055-1066
Climate is a group‐level phenomenon that should be measured and studied at the group level. The group level has theoretical and methodological advantages over the individual level. In this paper, I theoretically review the assumptions in measuring climate at the individual and group levels and demonstrate that the group‐level assumptions are more adequate for climate research because of their influences in exposure to events, interpretation of events, and preservation of perceptions. Methodologically, I discuss advantages in group‐level climate measurement accuracy that are based on multiple evaluators of climate and I suggest group aggregation is an organizational form of “wisdom of the crowds.” Finally, I point to three topics that remain to be investigated to understand climate at the group level better. The first is use of variability measures to compensate for information that is lost in aggregation. The second is challenging the assumption that formal organizational structure defines the group boundaries. I suggest that other levels of analysis apply to group‐level climate measurement and demonstrate the use of informal, more natural groups as an additional level. Third, I point to recently developed statistical procedures that can aid the study of climate perception emergence over time.  相似文献   
78.
The reproductive cycle of the sub-Antarctic spatangoid sea urchin, Abatus cavernosus, was examined during a 2-year period in southern Patagonia, Argentina. The population studied is the northernmost known coastal population in the austral oceans, and is influenced by a greater annual range of seawater temperature than other Abatus species. The sex ratio of the overall A. cavernosus population did not differ significantly from 1:1, but was not homogeneous across size classes. A clearly defined annual reproductive cycle was found. Spawning occurred from May to July and was synchronous between sexes. Females were observed to be brooding within a 9-month period, from May to February. Juveniles were released during the austral summer, from January to February. The length at which 50% of the females were brooding occurred at a test length of 25.9 mm. A. cavernosus had a large egg size (mean diameter = 1.4 mm) and low fecundity (maximum = 57 eggs per female) compared to closely related species. The number of eggs within each brood pouch was highest in larger anterior brood pouch, which is close to two gonopores, as opposed to the other anterior and two smaller posterior pouches. Significant interannual variation was observed in gonad cycles, fecundity, and embryo development such as: brood size decreased during 2001; adjusted gonad dry weight and fecundity were higher during 2003. Hypotheses concerning the gonadal and brooding cycles and fecundity of sub-Antarctic and Antarctic Schizasteridae are discussed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
79.
There are many reported associations between mussels and other invertebrates, such as pea crabs, polychaetes, turbellarians and copepods, which live in their mantle cavities. The boundary between commensalism and parasitism is often indistinguishable because of insufficient knowledge or because the interaction is variable. Preliminary evidence led to a closer examination of the relationship between the mussel, Mytilus edulis platensis, and an isopod, Edotia doellojuradoi, previously described as commensalism. Monthly intertidal samples of mussels were taken from September 2004 to August 2005 at Caleta Cordova Norte (45°43′S, 67°22′W) in southern Argentina and assessed for the prevalence and abundance levels of isopods. Mussels with and without isopods were measured, examined for evidence of gill damage and their condition (soft tissue dry weight) was determined. The overall isopod prevalence in mussels was 57.9% and infestation varied with mussel length, with maximum occurence at 30.2 mm (medium-sized mussels). Experimental evidence indicated that the position of the isopod inside the mussel depended on the feeding activity of the mussel. Female isopods were observed grasping the ventral food groove of the gill demibranchs and feeding on the mucous food strand produced by the mussel. Juveniles and males were observed clustered together on the dorsal side of the single female in each occupied mussel, suggesting extended maternal care. Gill damage was observed in 58.2% of mussels at the Argentine site and was significantly associated with isopod occurrence. Categorical regression analysis showed that the most important factor associated with the degree of gill lesions was the number of male and juvenile isopods per mussel, followed by the length of female isopods and the developmental stage of juveniles. Conversely, the degree of gill damage decreased with increasing mussel length. Overall, E. doellojuradoi had a significant effect on mussel condition throughout the year, with low flesh weight in mussels with isopods, except during the austral summer and early autumn. In contrast to previous studies, which concluded that the isopod was a commensal, the present study clearly demonstrates that E. doellojuradoi is a parasite of M. edulis platensis. Other symbiotic interactions formerly classified as commensal might not be innocuous on further investigation, especially if samples are taken at multiple sites and at different times of the year.  相似文献   
80.
The effects of the warm water discharged by a nuclear power plant (NPP) into a small reservoir are studied. A case study is presented (José Cabrera NPP-Zorita Hidráulica Reservoir) with experimental data of the reservoir stratification and predicted data of the dispersion of radioactive pollutants from operative or accidental releases. The vertical and longitudinal temperature profiles, electrical conductivity and transparency of the reservoir water were measured for an annual cycle. The results indicate that the continuous warm water discharge from the NPP causes permanent and artificial reservoir stratification. The stratification is significant within 1500 m upstream and 1000 m downstream from the warm water outfall. The pollutant dispersion has been predicted by using a flow model based on N(T) perfect-mixing compartments in series with feedback. The model parameter, N(T), is calculated from the longitudinal diffusion coefficient. The prediction of pollutant dispersion by means of this model shows that the stratification slows down the vertical mixing in the whole water body, and reduces the reservoir volume that is effective for the dilution and dispersion of pollutants. This means that, in the case of a radioactive pollutant release, the reservoir radioactivity level could increase significantly.  相似文献   
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