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931.
Sebastiscus marmoratus larvae were exposed to waterborne polycyclic aromatic hydrocarbons (PAHs) containing 3-5 rings, benzo[a]pyrene (BaP), pyrene (Py) or phenanthrene (Phe), respectively at 0.01, 0.1 and 1 μg L?1. Cumulative mortality, frequency of dorsal curvature and rate of pericardial and yolk sac edema in larvae treated for 8 days were significantly increased in a dose-dependent manner. All three PAHs resulted in reduction of the lower jaw, and the extent of reduction increased with increasing concentrations of the PAHs. Na+/K+-ATPase and Ca2+-ATPase activity in larvae exposed to the three PAHs were all significantly inhibited in a dose-dependent manner. Analysis using the Pearson correlation coefficient indicated a significant correlation between the rate of the dorsal curvature and edema and the inhibition of Na+/K+-ATPase and Ca2+-ATPase activity, suggesting that the developmental defects caused by PAHs were related to their inhibition of Na+/K+-ATPase and Ca2+-ATPase activity.  相似文献   
932.
Growth, haematological (haematocrit), biochemical (serum cortisol and glucose), and non-specific immune (lysozyme, serum haemolytic and haemagglutinating activities, extracellular respiratory burst activity) parameters, were monitored in European sea bass Dicentrarchus labrax and blackspot sea bream Pagellus bogaraveo subjected to a 31 days starvation compared to fed fish, to assess the responses to feed deprivation of these health status indicators. While haematocrit, serum cortisol, glucose and haemolytic activity of both species did not undergo significant variation following starvation, probably due to the short period applied, some non-specific immune parameters were affected significantly. In the starved sea bass, mucus lysozyme content doubled (1.8 U/mL) compared to the initial value. Haemagglutinating activity was significantly lower in starved sea bass than in fed fish after 31 days. In blackspot sea bream, a slight, not significant, reduction in haemagglutinating activity occurred 11 days after starvation. Respiratory burst activity decreased significantly in the starved fish. In spite of the limited number of examined parameters, the opportunity to use a panel of several indicators to obtain a more complete picture of health status in fish was underlined.  相似文献   
933.
Surface measurements of aerosol physical properties were made at Anantapur(14.62°N,77.65 °E,331 m a.s.l),a semiarid rural site in India,during August 2008-July 2009.Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity(RH<75%) using a Quartz Crystal Microbalance(QCM) in the 25-0.05 μm aerodynamic diameter range.The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 μg m-3,with a mean value of 34.02±9.05μgm-3 for the entire study period.A clear diurnal pattern appeared in coarse,accumulation and nucleation-mode particle concentrations,with two local maxima occurring in early morning and late evening hours.The concentration of coarse-mode particles was high during the summer season,with a maximum concentration of 11.81±0.98μgm-3 in the month of April,whereas accumulationmode concentration was observed to be high in the winter period contributed >68% to the total aerosol mass concentration.Accumulation aerosol mass fraction,A f(=Ma/Mt) was highest during winter(mean value of Af~0.80) and lowest(Af~0.64) during the monsoon season.The regression analysis shows that both R eff and R m are dependent on coarse-mode aerosols.The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm(AOD500) and PM 2.5 mass concentration([PM2.5]) shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period.  相似文献   
934.
935.
1INTRODUCTIONOneoftheeffectsofglobalwarmingisthatprecipita-tionhasincreasedoversomeareasintheworld,andthegaugedataofprecipitation (excludingAntarctica)showthatglobalprecipitationhasincreasedslightlybyabout9mmforthe20thcentury, whichwas verysmallcomparedwiththeinterannualandmul-ti-decadalvariability(NEWetal.,2001).Butregion-ally,thereexisted agreatdealofdifferences,suchasinmostpartsofAfrica, Amazon,westernSouthAmerica,theweatherhasbecomedrier,andinmostpartsofEuropeandCanada,thereexisted…  相似文献   
936.
地理学是对地球的描述。作为一门科学,它的起源和早期发展反映了十九世纪获取有关地球表层上极其多样的环境,人民和地方的信息的兴趣。它在某种程度上是为商业冒险的需要服务,但在更大的程度上仅仅是为了满足受过教育的富有阶级的好奇心。现在,这种好奇心莫名其妙地消失了,它(尤其在人文地理学中)已被一种对假想的普遍规律的关注所取代,这些规律是人对环境,空间、地方和人民的反应,却忽视了自然与人文背景的多样性,而正是这种多样性构成了地球表层压倒一切的特征。地理学者中这种取向的转移是目光短浅的,也是有害的。  相似文献   
937.
938.
本文试图陈述“边缘化”如何顺应关于“不平衡”、“空间与极化的增长”等多文献潮流首先,我们必须记住,可能在空间所表现的不平衡,并不一定是空间现象的本身,按安德森(Andrson,1983)等关于所谓工业衰退的“内城问题”的注解说:“这并不是……由于内城地点的原因而产生了问题,也不能从更广泛的社会过程中如普遍的经济危机不断变化的世界劳动分工等现象中,孤立地在本地区内寻求解决办法。”  相似文献   
939.
TENSORIAL RESOLUTION:A DIRECT TRILINEAR DECOMPOSITION   总被引:4,自引:0,他引:4  
Modern instrumentation in chemistry routinely generates two-dimensional(second-order)arrays of data.Considering that most analyses need to compare several samples,the analyst ends up with a three-dimensional(third-order)array which is difficult to visualize or interpret with the conventional statisticaltools.Some of these data arrays follow the so-called trilinear model,(?)These trilinear arrays of data are known to have unique factor analysis decompositions which correspondto the true physical factors that form the data,i.e.given the array (?),a unique solution can be found inmany cases for each order X,Y and Z.This is in contrast to the well-known second-order bilinear datafactor analysis,where the abstract solutions obtained are not unique and at best cannot be easilycompared with the underlying physical factors owing to a rotational ambiguity.Trilinear decompositions have had the disadvantage,however,that a non-linear optimization withmany parameters is necessary to reach a least-squares solution.This paper will introduce a method forreducing the problem to a rectangular generalized eigenvalue-eigenvector equation where the eigenbectorsare the contravariant form(pseudo-inverse)of the actual factors.It is shown that the method works wellwhen the factors are linearly independent in at least two orders(e.g.X_(jr),and Y_(jr) are full rank matrices).Finally,it is shown how trilinear decompositions relate to multicomponent calibration,curve resolutionand chemical analysis.  相似文献   
940.
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