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91.
Heavy metal (Hg, Pb, Cd, Cu, Ni, Fe, Zn, and Mn) contents of the samples from 10 males were followed throughout a year. The values were characteristic of the individuals, and some correlationships between the contents of different metals were shown.  相似文献   
92.
Polychlorinated biphenyl (PCB) residues from the sodium dispersion (SD) process were employed as the raw materials for the production of activated carbon using KOH activation. The pore properties, such as the specific surface area and pore size distribution, were characterized using the Barrett–Joyner–Halenda method and the Horvath–Kawazoe method based on the N2 adsorption isotherm at 77 K. The activated carbon produced showed similar adsorption capacities and specific surface areas to the commercially available product. The effects of the activation conditions on the porosity of the activated carbon produced were studied. The most significant factor affecting the specific surface proved to be the activation temperature. The activated carbon produced from PCB residues from the high-temperature (423–443 K) SD process had a binary pore size distribution well developed in the 4 nm region and in the micropore region. The pore structure of the carbon produced from PCB residues from the low-temperature (333–393 K) SD process had a wide range of micropores and mesopores.  相似文献   
93.
The pilchards (genus Sardinops), one of the major components of the world's harvest of fishes, is distributed sporadically in the temperate zone on a global scale. Mitochondrial DNA variation in 95 pilchards from nine worldwide localities in five current systems was examined using ten restriction enzymes. Although several opinions have been proposed on the global population structure of the genus Sardinops, our results clearly rejected the hypothesis of gene flow among geographically distant populations on a global scale. Results indicate that the Japanese pilchards and the Australian and South African pilchards were derived from the eastern Pacific populations, following the speciation of Sardinops in the Pacific, after the formation of the Isthmus of Panama. An intermixing of the northeastern and southeastern Pacific populations during the Pleistocene glacial maxima is suggested from their genetic affinities.  相似文献   
94.
The spatial distribution patterns of the nitrogen and phosphorus input/intake amounts in crop production within two small basins are examined, based upon a cropping unit distribution map that is obtained from remote sensing data analysis. Firstly, we examine the availability and suitability of approaches to the spatial distribution analysis of cultivation patterns classified from material flow characteristics of crop production using seasonal remote-sensing data. Secondly, material flow units in crop production are grouped according to the cultivation patterns obtained from the remote-sensing data analysis. Consequently, the spatial patterns of the amounts of both nitrogen and phosphorus inputs/intakes through crop production on farmland are examined and their spatial distribution maps are prepared according to the material flow units. In addition, we developed a nitrogen flow and runoff model and the model is simulated based on the examination of the results of spatial distribution patterns of the material flow units. The annual nitrogen runoff from small catchments, where various crops are cultivated, varies from 2.7 kg ha–1 year–1 to 108 kg ha–1 year–1 and the annual balanced losses of nitrogen in small catchments varied from –30 kg ha–1 year–1 to 101 kg ha–1 year–1. Also, the monthly changes in soil nitrogen of each material flow unit is estimated at –55 kg ha–1 as a maximum decrease and 114 kg ha–1 as a maximum increase. These results indicate that the spatial distribution patterns of nutrient input and intake through agricultural activities should be considered when analyzing the material flows and nutritient movement in soil–water systems in rural areas for watershed environmental control and regional agricultural management.  相似文献   
95.
In vivo exposure of rats to 10 ppm nitrogen dioxide (NO2) for 12h caused changes in fatty acids composition of alveolar lavage phospholipids. Among the fatty acid species, the relative ratio of palmitic acid, myristic acid and palmitoleic acid increased significantly. While the relative ratio of stearic acid, oleic acid, linoleic acid and arachidonic acid decreased significantly. Both the increase in the incorporation of palmitic acid in phosphatidylcholine which would be released into the alveoli and the increase in the release of phosphatidylcholine into the alveoli may account for the changes in the fatty acid composition of the present findings.  相似文献   
96.
Kobayashi N  Okamura H 《Chemosphere》2004,55(10):1403-1412
The toxicity of the polluted waters originating from a disused lead mine was evaluated using both sea urchin bioassays and heavy metal analysis. Samples from three polluted waters (a seawater and two freshwaters) were collected from the mine area and one seawater sample was taken from a non-contaminated reference site. The test waters contained higher concentrations of heavy metals such as manganese, lead, cadmium, zinc, chromium, nickel, iron, and copper than did ambient seawater. The three test waters had inhibitory effects, in a dose-dependent manner, on the first cleavage of sea urchin embryos and on pluteus formation during the development. Some malformations, such as a radialized pluteus, exo-gastrula, and spaceship Apollo-like embryos were induced by the test waters without dilution. Zinc alone also induced the same anomaly. Zinc in the test seawater was ascertained as one of the metals that caused the anomalies, but not all of the toxicity was caused by zinc. It was speculated that interactive effects, involving zinc and possibly manganese and nickel, were occurring.  相似文献   
97.
Chemical synthesis and physical properties of two mercapturic acids suggested as urinary metabolites of m- and p-xylenes ace described. These compounds may be used for the identification and quantivative determination by high-performance liquid chromatography of the corresponding mercapturic acids in urine.  相似文献   
98.
The growth cycle and related vertical distribution of the thecosomatous pteropod Spiratella (“Limacina”) helicina (Phipps) were studied. S. helicina has a life cycle of approximately 1.5 to 2 years in the central Arctic Ocean (Canada Basin). It spawns mainly during the spring to summer period, and on a small scale during the winter. The young double their sizes during the winter months of October to May, slow down in growth until late summer, and attain maximum size in early winter. The oldest disappear by late March. Gonadal tissue was first seen in young pteropods of 0.7 mm diameter, the predominant size from February to April. S. helicina 0.8 mm in diameter, the size predominant from May through July, are mature and hermaphroditic. Growth during the winter months suggests that particulate organic matter is available during this period to these obligate ciliary feeders. Vertical distribution is size and season-dependent. The youngest specimens collected (0.2 to 0.4 mm) were found concentrated in the first 50 m. The larger sizes dispersed during the summer months, and tended to concentrate in the top 150 m during the rest of the year. They aggregated in the top 50 m from late winter through early spring, and fall through early winter; then concentrated in the 100 to 50 m level until the end of winter. Numerous environmental factors seem to be involved in determining the vertical distribution of the species in the central Arctic Ocean.  相似文献   
99.
Climate change adaptation practices of apple growers in Nagano, Japan   总被引:1,自引:0,他引:1  
By an interview survey with apple growers in Nagano Prefecture, Japan, we found that their recognition of and reaction to climate change depends on their sales channels. Against rising air temperature, more farmers on direct sales (Type D farmers) than those on sales via the markets (Type M farmers) recognized the delay in fruit maturity as the effect of climate change, specifically temperature rise, (Type D: 62%, Type M: 15%). In response to the delay in maturity, Type D farmers simply delayed the harvest to full maturity by about 10 days than they did 20 years ago. On the other hand, Type M farmers recognized delayed reddening of the fruits as the most salient result of climate change (Type D: 8%, Type M: 46%), and took measures to accelerate the coloring by placing reflective materials on ground and/or picking off leaves around the fruits. The contrasting behaviors can be explained by the difference in the critical trait of the products. For Type M farmers, timing of the shipment is critical to avoid competition with shipments from other apple growing areas, and the good coloring is the prerequisite for the shipment. For Type D farmers, by contrast, full maturity is more important than coloring, since their contract with the customers hinges on the palatability of the fruits rather than the timing. This study has thus identified positioning of the farmers with the sales channel as a determinant in their adaptation behavior and vulnerability to climatic changes.  相似文献   
100.
开放式臭氧浓度升高对2个冬小麦品种光合损伤的研究   总被引:11,自引:5,他引:6  
在开放式臭氧浓度升高(ozone-free air controlled enrichment,O3-FACE)平台上,观测了高浓度臭氧(正常大气臭氧浓度的基础上增加50%)对2个冬小麦(Tritcium aestivum L.)品种(烟农19和扬麦16)在灌浆期内功能叶片光合损伤的情况.观测显示,整个灌浆期内2个小麦品种有关参数响应的趋势表现一致:①净光合速率(Pn)逐渐下降,在臭氧处理35 d时,烟农19和扬麦16降幅分别达到56.21%和21.82%.②荧光动力学参数Fv/Fm(最大光化学量子产量)、qp(光化学淬灭系数)、Φexc(PSⅡ有效光化学量子产量)、ΦPSⅡ(PSⅡ实际光化学量子产量)呈下降趋势,NPQ(非光化学淬灭系数)逐渐上升;在能量分配方面,吸收的光能在PSⅡ天线色素的耗散部分(%D)升高、用于PSⅡ光化学反应的部分(%P)降低,而不属于前两者的其它消耗部分(%X)变化不明显.在臭氧处理35 d时,烟农19和扬麦16的ΦPSⅡ分别下降24.42%和9.97%.③光合色素参数Chla/Chlb(叶绿素a/叶绿素b)比值上升,而Chlt/Car(叶绿素/叶黄素)的比值下降.④叶绿体内依赖Mg2+、Ca2+的ATPase(ATP酶)活性和ATP含量均增加.上述参数随臭氧处理时间延长,变化幅度和品种间的差异趋于显著,当臭氧处理35 d时,变幅最大,且烟农19变幅显著大于扬麦16.结果表明,在臭氧浓度升高环境下,作物通过增加热耗散、改变色素含量和结构、提高ATPase活性等进行防御和损伤修复.随着处理时间的增加,臭氧对冬小麦的光合损伤具有累积效应,且2个品种表现出较大的差异性.  相似文献   
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