热带海洋珍珠贝类立克次体病研究 Ⅳ.组织细胞病理学研究

类立克次体(RLO)对大珠母贝和合浦珠母贝具有强烈的致病性,引起基本一致的病理变化.在急性坏死破坏期内,RLO导致外套膜、鳃、消化管、肝胰腺、生殖腺腺管及全身血管内皮系统等多器官组织的变性坏死,使器官组织结构的完整性遭到破坏,破坏程度与RLO包涵体的数目密切相关,而细胞的破坏与细胞内RLO的生长发育及繁殖到大量数目密切相关.鉴于此,将RLO引起的珍珠贝病称为类立克次体病(RLO病).RLO病呈急性变质性炎症和慢性增生性炎症病理,在前者细胞呈现崩解性坏死、溶解性坏死和退变性坏死;在后者存在实质细胞增生和纤维母细胞增生为纤维细胞并形成纤维化.根据炎症病理的发展过程,RLO病可分为急性坏死破坏期和慢性增生修复期.     

试论洞庭湖的特征与治理

本文较全面地论述了洞庭湖（区）的特征,治理洞庭湖的必要性、重要性以及可行性。洞庭湖如不治理,少则100年,多则500年,就会因泥沙的淤积而消失。因此作者提出了 “开流节源,治江保湖”,“增秸扩池,治湖保湖”,以及维护和加强防洪工程等治理洞庭湖的设想。     

高质量发展下用海效益评估方法研究——以台州市为例

实际用海效益包括海域资源在生产过程中产生的直接经济收益和生态环境系统的负面效应,文章通过建立海洋高质量用海效益评估模型反映和量化实际用海效益,并将该模型在台州市海域应用,研究结果发现,台州市涉海县、市、区中椒江区实际单位用海效益最高为68.85万元/hm2,玉环市最低为4.02万元/ hm2。原因在于椒江区不仅其海域资源价值表现良好,而且生态环境损害程度得到了有效控制。从而得出,海洋经济高质量发展绝对不是海域资源过度使用,也不是海洋生态环境的绝对保护,两者是相互统一、相互协调的,保证海域资源使用价值保值增值是海洋经济合理运行的基础,保护海洋生态环境系统是海域资源使用价值保值增值的根本,这是引导海洋经济高质量发展的重要路径。     

基于局部采样MCMC方法的时移探地雷达反演

马尔科夫链蒙特卡洛方法(MCMC)是一种启发式的全局寻优算法,可以用来解决概率反演的问题.基于MCMC方法的反演不依赖于准确的初始模型,可以引入任意复杂的先验信息,通过对先验概率密度函数的采样来获得大量的后验概率分布样本,在寻找最优解的过程中可以跳出局部最优得到全局最优解.MCMC方法由于计算量巨大,应用难度较高,在地...     

龙门山地区历史强震数值模拟

考虑区域地质构造差异、主要活动断裂分布特征和地表附加重力影响,建立反映龙门山地区地表起伏和岩石圈分层的三维粘弹性有限元模型。以GPS为约束重建研究区现今构造应力场,依次模拟龙门山地区1900年以来发生的5次M_S 7.0以上地震,从库仑应力和等效应力角度,分析应力场演化对强震的影响以及强震间的相互作用关系。研究结果表明:从库仑应力角度,有3次地震对后续地震有促进作用,其中汶川地震对芦山地震有触发作用;从等效应力角度,有4次地震对后续地震的发生具有加速作用。     

2016年3月21日金塔县M_S 4.7地震强震动记录分析

2016年3月21日11时29分甘肃省酒泉市金塔县发生M_S 4.7地震,甘肃省强震动台网中心收集到5组三分向加速度记录,常规处理后得到15条零基线校正后的三分向峰值加速度(PGA),选取土层台基类型的62XID台站加速度记录(PGA数值最大)进行分析,绘制校正后的加速度、速度和位移时程曲线及加速度反应谱,为中国西部工程震害调查提供参考资料。     

Numerical analysis of multicomponent responses of surface-hole transient electromagnetic method

We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular local targets. We also propose a calculation and analysis scheme based on numerical simulations of the subsurface transient electromagnetic fields. In the modeling of the electromagnetic fields, the forward modeling simulations are performed by using the finite-difference time-domain method and the discrete image method, which combines the Gaver–Stehfest inverse Laplace transform with the Prony method to solve the initial electromagnetic fields. The precision in the iterative computations is ensured by using the transmission boundary conditions. For the response analysis, we customize geoelectric models consisting of near-borehole targets and conductive wall rocks and implement forward modeling simulations. The observed electric fields are converted into induced electromotive force responses using multicomponent observation devices. By comparing the transient electric fields and multicomponent responses under different conditions, we suggest that the multicomponent-induced electromotive force responses are related to the horizontal and vertical gradient variations of the transient electric field at different times. The characteristics of the response are determined by the varying the subsurface transient electromagnetic fields, i.e., diffusion, attenuation and distortion, under different conditions as well as the electromagnetic fields at the observation positions. The calculation and analysis scheme of the response consider the surrounding rocks and the anomalous field of the local targets. It therefore can account for the geological data better than conventional transient field response analysis of local targets.     

从库仑破裂应力和余震分布角度探讨汶川地震和芦山地震的关系

本文以龙门山及周边地区为研究对象,考虑区域地质构造差异、主要活动断裂带、地表附加重力影响,建立能反映地表起伏和岩石圈分层结构的龙门山地区三维粘弹性有限元模型。以地壳水平运动速率观测值为约束条件重建研究区现今构造背景应力场,在此基础上分别模拟了汶川地震和芦山地震的发生机理。通过分析同震库仑破裂应力变化与余震空间分布的关系,探讨了2次地震主震对余震的触发作用以及汶川地震对芦山地震的影响。研究表明,汶川地震和芦山地震的余震大部分由其主震触发,汶川地震对芦山地震的余震有约6.78%的触发作用。汶川地震的同震库仑破裂应力在芦山地震主震位置的增加值约为0.016MPa,如果龙门山断裂带南段库仑破裂应力年累积速率按照0.4×10-3-0.6×10-3MPa·a-1计算,汶川地震使芦山地震提前了约27-40年。计算还表明汶川地震和芦山地震的发生使鲜水河断裂带南段和虎牙断裂的库仑破裂应力增加,这些断裂带在未来发生地震的可能性增加。     

Trend analysis of nutrient loadings in a large prairie catchment

Nutrient loadings in many river catchments continue to increase due to rapid expansion of agriculture, urban and industrial development, and population growth. Nutrient enrichment of water bodies has intensified eutrophication which degrades water quality and ecosystem health. In this study, we carried out a trend analysis of total phosphorus and total nitrogen loads in the South Saskatchewan River (SSR) catchment using a novel approach to analyse nutrient time series. Seasonal analysis of trends at each of the water quality stations was performed to determine the relationships between annual flow regimes and nutrient loads in the catchment, in particular, the influence of the high spring runoff on nutrient export. Decadal analysis was also performed to determine the long-term relationships of nutrients with anthropogenic changes in the catchment. Although it was found that seasonal and historical variability of nutrient load trends is mainly determined by streamflow regime changes, there is evidence that increases in nitrogen concentration can also be attributed to anthropogenic changes.     

Distribution characteristics and controlling factors of typical heavy metals in Huanghe River estuary,China

Journal of Oceanology and Limnology - The geochemical characteristics and potential controlling factors of colloidal Zn, Cd, and Pb in Huanghe (Yellow) River estuary (HRE), China were investigated....