Effects of molting and environmental factors on trace metal body-burdens and hemocyanin concentrations in the American lobster, Homarus americanus   总被引：4，自引：0，他引：4  

Engel DW  Brouwer M  Mercaldo-Allen R 《Marine environmental research》2001,52(3):257-269

Hemocyanin concentrations in the hemolymph of marine crustacea are dependent on the molt cycle and on environmental conditions. Studies in our laboratories have found that hemocyanin levels in blue crabs are reduced after ecdysis and under conditions of environmental stress (Engel, Brouwer, & McKenna, 1993. Hemocyanin concentrations in marine crustaceans as a function of environmental conditions. Marine Ecology Progress Series, 93, 233-244). We have extended those studies to include the American lobster, Homarus americanus. Hemolymph and digestive gland tissues from Long Island Sound lobsters were analyzed for hemocyanin, copper, and zinc during different stages of the molt cycle. Hemocyanin, copper and zinc in the hemolymph were highest in premolt stages (D1-D4), and lowest in the postecdysal papershell stages (B1-B2). Concomitantly, copper in digestive glands decreased significantly following ecdysis, but no significant changes in the metals bound to metallothionein (MT) were observed. Copper-MT was the predominant form throughout the molt cycle, presumably because lobsters were obtained from copper-contaminated areas. To examine the effects of environmental factors, intermolt lobsters were collected from locations of different environmental quality along the Atlantic coast, and were analyzed for hemocyanin and trace metals. In general, animals from areas with a history of contamination showed the highest hemocyanin concentrations.  相似文献   

1906年地震的远域余震     

Stee.  DW 刘慧洁 《世界地震译丛》1998,(4):43-46

在１９０６年４月１８日加州旧金山大地震后的２４ｈ之内,俄勒冈州的佩斯利,亚利桑那州的莫尼克斯,加州的洛杉矶,布劳利都分别感到了地震。运用概率理论,结果表明同一天内在这些散布地区的每一个地点都发生有感地震是感见的。对１９０６年地震后２４ｈ内经受过地震的４个不同区域,确定了１８９７￣１９０６年９ａ间有感地震的发生率。我们用盒子里摸球概率问题的思想模拟了余震发生的似然性。结果表明,大地震余震区至少可延伸  相似文献   

地球物理反演在矿产勘查中的应用     

Olde.  DW 胡祥云 《地质科学译丛》1998,15(3):46-48

借助于计算机技术和数学优化理论所产生的新算法,对各种地球物理数据,选择特定的目标函数及物性参数进行迭代反演计算,最后恢复出能够反映实际成矿条件和地质特征的一维,二维及三维图像。  相似文献   

斑岩铜金矿床地地球物理的数据的反演：米利根山的一个研究案例     

Olde.  DW 吴其斌 《物探化探译丛》1998,(2):38-37

在本文中,我们反演了米利根山斑岩铜金矿床的磁测、直流电阻率、激发极化（ＩＰ）和航空电磁数据,并将反演结果与已有的地质和矿化资料作综合解释。反演的区域内有一个侵入岩株,称之为ＭＢＸ岩体,区域周围遍布矿化带。在地模型被离散为许多单元,每个单元的物性恒定,构建与相应数据充分拟合的模型目标函数,通过使目标函数最小救是磁化率、电导率和极化率的分布。直接反演地面总场数据求取３－Ｄ磁化率模型。反演ＤＣ／ＩＰ数据  相似文献   

A geographical analysis of multiethnic households in the United States     

Wong DW 《International journal of population geography : IJPG》1999,5(1):31-48

"Using the household-level data provided by the 5% PUMS [Public Use Microdata Sample] data from the 1990 Census, this paper reports the pattern of ethnic mixing at the household level in the U.S. and also describes the geographical patterns of different types of multiethnic households at both the state level and the PUMA [Public Use Microdata Area] level. Several of the largest metropolitan areas are also examined in greater detail. The strong dominance of whites in the process of ethnic mixing is clear, as is the expected dominance of blacks in southeastern U.S. and the dominance of Hispanics in the southwest at the state level. The PUMA-level analysis reveals local clusters of ethnic mixing that are not apparent at the state-level analysis."  相似文献   

Occurrence and biological impacts of fishing gear and other marine debris in the Florida Keys   总被引：1，自引：0，他引：1  

Chiappone M  White A  Swanson DW  Miller SL 《Marine pollution bulletin》2002,44(7):597-604

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Chlorohydrocarbon pesticides in the Australian marine environment after banning in the period from the 1970s to 1980s     

Connell DW  Miller G  Anderson S 《Marine pollution bulletin》2002,45(1-12):78-83

The chlorohydrocarbon pesticides (CHPs) (principally DDT, dieldrin, hexachlorocyclohexane (HCH) including lindane, chlordane, heptachlor and heptachlorepoxide, aldrin and hexachlorobenzene (HCB)) were used extensively in Australia during the 1960s and 1970s. These were progressively banned from the 1970s with DDT being totally banned in 1987. The levels in marine waters are believed to have progressively declined as indicated by water in the Brisbane River, which consistently fell from maximum concentrations of about 1.7 μg/l in 1972–1973 to not detectable in 1986–1987. In some urban areas sediment concentrations, up to 1700 μg/kg dry weight, were recorded in the early 1990s which may reflect the reworking and exposure of older more contaminated material. Fish exhibited consistent occurrence of DDT, HCH, dieldrin and HCB through the 1970s to the 1990s. Maximum concentrations of DDT and dieldrin occurred generally in the 1970s at 40.3 and 8.8 μg/g wet weight, and minimums in the 1990s at 2.4 and 0.041 μg/g wet weight respectively. Inputs of dialdrin from sewage and DDT from the broad environment, reflected by the calculated daily human uptake in the diet, were shown to decline with half-lives of 1.1–1.5 and about 3 years respectively. This evidence suggests that banning of the CHPs has greatly reduced the inputs into the marine environment with consequent reductions in concentrations in biota but there is the occasional occurrence of relatively high concentrations.  相似文献   

风蚀：野外观测     

Frur.  DW 董治宝 《世界沙漠研究》1994,(2):9-11

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Trace metals and nutrients in bottom sediments of the Southport Broadwater, Australia     

Burton ED  Phillips IR  Hawker DW 《Marine pollution bulletin》2004,48(3-4):378-384

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