Lysosomal Membrane Stability and Metallothioneins in Digestive Gland of Mussels (Mytilus galloprovincialis Lam.) as Biomarkers in a Field Study     

S. Petrovi&#x;  B. Ozreti&#x;  M. Krajnovi&#x;-Ozreti&#x;  D. Bobinac 《Marine pollution bulletin》2001,42(12)

The lysosomal membrane destabilization and the metallothionein content in the digestive gland cells of mussels (Mytilus galloprovincialis Lam.), collected along the east coast of the North Adriatic (Istrian and Kvarnerine coast, Croatia), were examined over a period of four years (1996–1999). The lysosomal membrane stability, as a biomarker of general stress, showed that the membrane labilization period in mussels from polluted, urban- and industrial-related areas was significantly decreased (p<0.05) when compared to mussels from control, clean sea water sites. In the harbour of Rijeka, the most contaminated site, the lysosomal membrane stability was reduced by more than 70% compared to the control. This method also proved to be a useful biomarker for detection of additional stress caused by short-term hypoxia that occurred once during this study inside the polluted and periodically quite eutrophic Pula Harbour. The concentration of metallothioneins in the mussel digestive gland, as a specific biomarker of exposure to heavy metals, did not reveal significant differences (p<0.05) between sites covered by this study.  相似文献   

Factors affecting sediment trapping in vegetated filter strips: simulation study using VFSMOD   总被引：1，自引：0，他引：1  

Majed Abu‐Zreig 《水文研究》2001,15(8):1477-1488

Soil and water conservation practices have been promoted for a long time, in order to sustain agricultural activities and prevent environmental pollution. Vegetated filter strips (VFS) have been used to reduce sediment pollution into water bodies at or near the pollutant source. However, factors effecting VFS performance under natural conditions have not been well understood owing to the physical, time and financial limitations of field experiments. The use of well‐validated simulation models to understand the performance of VFS and factors affecting sediment deposition is highly justified. The objective of this research is to investigate sediment trapping in VFS and to study various factors affecting VFS performance using the simulation model VFSMOD, which was developed by researchers at University of North Carolina. Recently, VFSMOD has been validated successfully by using 21 filters with varying length, slope and vegetated cover. A wide range of five parameters was selected for the simulations, namely filter length, filter slope, manning roughness coefficient, soil type and characteristics of incoming sediment from adjacent fields. Computer simulations revealed that the length of filter is the most significant factor affecting sediment trapping in VFS. The relative increase in trapping efficiencies was not linearly related to an increase in filter length. Inflow sediment class also has a major influence on sediment trapping in VFS. The trapping efficiency of clay sediments in a 15 m length VFS was 47% compared with 92% for silt from incoming sediment. Manning roughness coefficient had a moderate effect on sediment trapping and was more significant in short filters. Land slope and soil type of VFS had a minor influence on the performance of VFS. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

水下机动目标轨迹跟踪的自适应估计方法     

奚锐锋  刘经南  陶本藻  陆立发 《武汉大学学报(信息科学版)》1996,(1)

研究了用ＧＰＳ测定基阵坐标，分析了水听器基阵所接收到的声脉冲信号的处理。通过模拟和实测数据的试算，证明了本文提出的模型及方法不但能处理多系统含有粗差的观测值，而且具有良好的跟踪处理机动目标的性能。  相似文献   

星载SAR图象斑点噪声消除方法效果的比较研究     

唐伶俐  江平  戴昌达 《遥感学报》1996,(3)

星载（ＳＡＲ）图象一般都存在相干斑点噪声，严重干扰地物信息的提取与ＳＡＲ图象的应用效果，因此斑点噪声的消除问题引起微波遥感科技工作者的普遍关注，先后有多位学者提出各种不同的处理方法，其中最为常用的有均值平滑滤波、中值平滑滤波、Ｆｒｏｓｔ自适应滤波、Ｌｅｅ自适应滤波以及近期由Ｐ．Ｖ．ＮａｒａｓｉｍｈａＲａｏ等人提出的改良Ｋ－均值自适应滤波等方法。本文分析了这几种方法的数学基础，并选择了有代表性的实验区开展对比试验，结果表明：改良Ｋ－均值自适应滤波法效果最佳。  相似文献   

From surface electrical properties to spontaneous potentials in porous media   总被引：1，自引：0，他引：1  

A. Revil  M. Darot  P. A. Pezard 《Surveys in Geophysics》1996,17(3):331-346

This paper deals with the electrical double layer and the related properties of porous media. In particular, the electrical conductivity, the streaming potential, and the membrane potential are described in a self-consistent set of equations. All these properties are shown to be governed by fluid-matrix interface properties, as well as four geometrical parameters.  相似文献   

利用多项式拟合模板法消除地震数据中的低频随机干扰          下载免费PDF全文

田小平  丁玉美 《地球物理学报》1996,39(Z1):309-315

提出利用多项式拟合模板法消除地震数据中的低频随机干扰，分析模板的性质并推导出模板参数与低频随机干扰最高频率之间的关系式。  相似文献   

用人工神经网络实现地震记录中的废道自动切除   总被引：2，自引：0，他引：2       下载免费PDF全文

张学工  李衍达 《地球物理学报》1992,35(5):637-643

切除废道（即道编辑）的工作是地震信号处理中重要而又工作量巨大的一步.本文提出了一种用人工神经网络实现的自动切除方法,所用的神经网络模型为新奇滤波器模型,方法简单实用,切除效果令人满意.文中介绍了方法的原理并给出了几个实验结果.  相似文献   

以T42产品为因子用卡尔曼滤波方法作温度预报   总被引：3，自引：4，他引：3  

朱正心  徐竞平 《气象科学》1995,15(1):85-88

本文以Ｔ４２数据预报产品为因子，用卡尔曼滤波方法建立可更新系数的预报方程作南京和芜湖的温度预报。从１９９４年１月至４月共８４次试报中，用完全相同的因子卡尔曼滤波方法比回归分析方法预报结果精度提高０．５度。  相似文献   

Strain segmentation and lateral membrane deformation rate of the subducted Ryukyu slab     

LingYun  Chiao 《Island Arc》1993,2(2):94-103

Abstract Focal mechanisms of intermediate-depth earthquakes within the subducted Ryukyu slab indicate a systematic pattern of down-dip extension in the northern part under Kyushu. These mechanisms switch rapidly around the Tokara channel to down-dip compression in the southern part toward Taiwan. This intriguing pattern of strain segmentation, together with the differences between the slab geometry of the northern and southern parts, has raised the question of whether stress segmentation, as defined possibly by a tear fault, might exist in the slab. However the Ryukyu trench has a concave oceanward shape in the northern segment while it is convex in the southern oceanward part toward Taiwan. The inflection zone is located around the Tokara channel. The concept of Gaussian curvature of a curved surface suggests that the along-arc variation of the geometric configuration of a subducted slab is related to the shape of the trench. This is in order to accommodate the lateral membrane deformation of the slab as the oceanic lithosphere subducts from a spherical shell to the geometry delineated by the Wadati-Benioff zone. The membrane deformation regime of the subducted Ryukyu slab and its relation with the trench geometry was examined by assuming that the subduction be modelled by the flow field of a thin viscous sheet. A projection operator was utilized to compute the membrane strain-rate tensor of an arbitrary non-Euclidean surface. Numerical experiments indicated that the northern segment of the slab was dominated by lateral compression and down-dip extension and the southern part by lateral extension and down-dip compression. This transition is sharply located near the Tokara channel. These patterns were compatible with what had been observed from studies of focal mechanisms, suggesting that the strain segmentation might be controlled, at least in part, by the lateral membrane deformation within the slab due to the trench shape in this subduction zone. The slab geometry was predicted by minimizing the integrated total dissipation power; this revealed distinct features that were consistent with observations. This implies that the slab geometry may also be affected by the membrane deformation in a systematic fashion.  相似文献   

2016年度呼图壁地下天然储气库对周缘微地震活动性的影响          下载免费PDF全文

张卓然  魏斌  申宗航  乌尼尔  王涛  王宝善  阮友谊 《地球物理学报》1954,63(9):3387-3397

呼图壁储气库是中国目前存储量最大的天然气储气库,位于新疆准噶尔盆地南缘,北天山山前坳陷带内的呼图壁背斜上.储气库靠近百万人口大城市乌鲁木齐,气库的注放气活动对其周缘地震活动的长期影响是事关生产和生活的重要安全问题.本文以呼图壁储气库为中心,在86.5°E—87.5°E,43.5°N—44.5°N的范围内,基于新疆维吾尔自治区地震局在该区域建立的密集流动台阵数据,应用模板匹配滤波技术对2016年全年的波形数据进行搜索识别,检测到遗漏地震事件151个,完善扩充了原有地震目录,使得该区域完备震级由1.1降到约0.7.通过分析新目录中404个地震的时空分布规律,我们发现2016年,即气库建成第三年以后,储气库的气压变化依然会影响周缘地区的地震活动.当储气库的气压增大到超过约22 MPa的阈值后,较小的气压波动也会导致该区域地震活动性明显增强;气压变化对距储气库中心最远约40 km范围内区域的地震活动存在较为明显的影响.  相似文献