渤海波浪和潮汐风暴潮相互作用对波浪影响的数值研究

基于依赖波浪成长状态波令的表面风应力，提出了一个波浪和风暴潮潮汐运动相互作用的联合数值模式，实现了第三代波浪模式和三维风暴潮潮汐模式联合作用的数值研究，并结合渤海典型天气个例的研究，给出了渤海波浪和风暴潮潮汐相互作用对波浪影响的机制和大小量级的定量估计。研究表明，对不同天气过程，波浪和风暴潮潮汐相互作用对波浪影响的性质和大小不同；对强寒潮过程，对波浪影响主要由风暴潮所支配波高调制可达1m，在黄河口区一般达0．5m；对弱天气过程，对波浪影响主要由潮所控制，波高调制约在0．2m，联合作用模式给出的结果与实测更吻合。     

估算总蒸发的方法

精密的蒸发渗漏仪(Lysimeter)提供了精确测定Et(总蒸发)的唯一直接途径。但由于蒸发渗漏仪的安装和使用需要投资、时间和专门技术,所以其它一些估算Ft的方法是必要的。工程师、农学家和水文工作者及其它工作者都需要精确地估算Et以用于多种目的。为了满足这个需要,这里将对一些比较常用的估算Et的方     

古水文

通过古水文参数对重建古环境尽管有一定局限性,但对恢复古环境仍提供了重要证据。的确,在大陆上的许多地区,第四纪河流沉积物是唯一易于研究古环境的记录。     

巴布亚—新几内亚Frieda河远景区地质简介

Frieda河远景区,位于巴布亚—新几内亚西Sepik行政区的Sepik河北部支流地区,地处南纬4°41＇,东经141°47＇。在该远景区内,火成岩占有大约200平方公里以上的面积,且具有斑岩铜矿床和黄铁矿质交代型的铜—金矿床。本文主要论述火成杂岩体的岩石学和地球化学,以及火成岩和成矿作用的地质年代。一、区域地质背景尽管Dow等(1972)和Davies(1979)曾经阐述过该远景区的区域地质,但仅在本文中才     

地球早期地质生物化学演化

绪言近年来,目的在于对地球形成及其早期演化过程作出解释的研究日益增多。相应的资料来自以古老地体调查为根据的各种各样野外和实验室数据,包括实验岩石学研究、地球化学计算、微生物学和天文学考察。本文考虑到地球早期地质生物化学演化的各个方面,综合资料适用于上述种种来源,从而发挥和刷新了由Lambert和Groves(1981)所提出的许多结论。第一节中提     

正直近景摄影测量的精度(方程式的推演并和模拟法比较结果)

在摄影测量的模拟和解析的应用中,垂直式摄影测量应用的最普遍。在正直近景摄影测量的情况下,应用垂直式航空摄影测量学估算精度的公式,得不到满意的结果。因此,为了估算近景摄影测量的精度,应用数学模型(模拟)的方法。用模拟的方法所获得的估算精度与实际应用中所获得的精度相符。但是,模拟方法花钱多而且工艺复杂。这篇论文用数学和实验证明了估算正直近景摄影测量和航空摄影测量精度新推导出来的公式。     

Concentrations of Cd,Zn and Cu in sediments and brown shrimp (Crangon crangon L.) from the Severn Estuary and Bristol Channel,UK

Cd, Zn and Cu levels were determined in sediments and Crangon crangon from 9 sites in the Severn Estuary/Bristol Channel during winter 1999. Metal levels in both shrimp and sediments varied significantly between sites and were related to proximity of input and/or sediment type. In the upper Estuary, Cd levels in shrimp were 100x higher than other reported values whereas sediment Cd contamination was comparable. It is suggested that high Cd levels in shrimp are due to the high inputs and enhanced bioavailability of metal during winter.     

Cadmium detoxification processes in the digestive gland of cephalopods in relation to accumulated cadmium concentrations

The high concentrations of cadmium recorded in the digestive gland of cephalopods from various temperate and subpolar waters suggest that these molluscs have developed efficient cadmium detoxification mechanisms. The subcellular distribution of cadmium in the digestive gland cells was investigated in seven cephalopod species from the Bay of Biscay (France) and the Faroe Islands. In most species, cadmium was mainly found in the cytosolic fraction of the digestive gland cells, reaching up to 86% of the total cadmium for the squid Loligo vulgaris from the Bay of Biscay. But species with the highest total level of cadmium showed a higher percentage of cadmium associated to insoluble compounds. The quantification of metallothioneins (MTs) by the polarographic method was performed in order to evaluate the involvement of these proteins in the detoxification of the high amounts of bioaccumulated cadmium. Metallothionein levels in cephalopods ranged form 742 +/- 270 to 3478 +/- 1572 microg/g wet weight. No relationship could be established between total cadmium, cytosolic cadmium and MT levels suggesting the occurrence of other Cd-binding ligands. Although these proteins have not been characterised, as cadmium in the digestive gland of cephalopods is mainly associated with soluble ligands, a high potential transfer to predators can be predicted.     

Oxygen radicals production and actin filament disruption in bivalve haemocytes treated with benzo(a)pyrene

Haemocytes play an essential role in the internal defence of molluscs. It has been reported that organic xenobiotics commonly found as pollutants in the marine environment impair defence capabilities of haemocytes. The purpose of the present study was to investigate the effects of benzo(a)pyrene [B(a)P] on the integrity of the actin cytoskeleton and on endocytosis in haemocytes and to see if these effects are related to generation of reactive oxygen species. Haemocytes were exposed in vitro to B(a)P (0.5-40 microg/ml) for 1 h. Cell viability (using 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide or XTT assay) indicated that selected doses were sublethal. Uptake of neutral red was significantly decreased in a dose-dependent manner in B(a)P-treated haemocytes. Distribution of actin filaments, labeled with rhodamine-conjugated phalloidin, was altered in haemocytes treated with 20 or 40 microg/ml B(a)P. These effects could be related to an increased production of superoxide anion during B(a)P metabolism, as detected by the nitroblue tetrazolium (NBT) reduction assay in haemocytes treated with > or = 10 microg/ml B(a)P.