Developing water quality standards for coastal dolphins     

Thompson PM 《Marine pollution bulletin》2007,54(2):123-127

The EU Habitats Directive requires Member States to consider the potential impact of sewage discharges on protected wildlife populations, but efforts to reduce these threats are constrained by the lack of appropriate water quality guidelines for wildlife. In Scotland, recommendations for higher discharge standards in areas frequented by bottlenose dolphins have been criticised on the basis of scientific uncertainty. This Viewpoint article outlines the background to this issue, and discusses whether the scientific frameworks used for assessing water quality standards for human bathers can realistically be used to develop water quality standards for coastal dolphins. Importantly, it highlights that widely accepted EU standards for human bathers are based on extremely limited scientific data, and argues that unrealistic demands for empirical data from wildlife populations should not prevent more precautionary measures being introduced to reduce disease risks to these species.  相似文献   

对虾养殖防病新模式初步研究     

崇明  蔡生力  宋晓玲  杨丛海 《海洋科学》1995,19(2):42-47

设计了一个对虾养殖防病新模式，并进行了小规模试验，获得初步成功。在４个３０～４０ｍ＾２的露天水泥池中，各放入３ｃｍ的大苗５００～７００尾（每亩约１００００尾），经９０余天的养殖，对虾成活率８０％左右，个体１０ｃｍ，平均体重８０尾／ｋｇ，饵料系数约１．５。新模式的立足点是防病，特点是设置一蓄水沉淀池，用含氯消毒剂处理养殖用水，配备充气增氧设施，选择优质配饵，合理投喂，使各种水质理化因子及生物因子尽量  相似文献   

壳多糖对罗氏沼虾、斑节对虾苗生长和抗菌防病作用研究     

庄承纪  刘劲科  杨清友  李强 《广东海洋大学学报》1998,(3)

探讨壳多糖（chitosan）对虾苗的生长和抗菌防病的作用。用玻璃缸培育罗氏沼虾和斑节对虾苗,在水体中添加不同浓度的壳多糖,人为感染气单胞菌或弧菌,观测虾苗的生长和抗病情况。结果表明：（1）在培养水体中加入壳多糖（50×10-6）能净化水质,防止水质恶化,因而可进行不换水育苗;（2）壳多糖（25×10-6～100×10-6）可抑制气单胞菌和弧菌的生长繁殖,增强抗病能力,提高虾苗的成活率;（3）适宜浓度25×10－6～50×10-6）的壳多糖对虾苗的生长有促进作用。  相似文献   

有建筑物存在的饱和砂土地基液化振动台模拟实验研究   总被引：15，自引：5，他引：10  

陈文化  门福录  景立平  王德润 《地震工程与工程振动》1998,18(4):54-60

对建筑物地基的液化问题至今研究得尚不够充分。我们在已有的国内外研究成果的基础上,在已 有的振动台等试验条件下,做了一批试验,以进一步步证和完善已有的工作。  相似文献   

Assessment of seismic resistance of masonry structures including boundary conditions     

Emília Juhsov  Milan Hurk  Zbigniew Zembaty 《Soil Dynamics and Earthquake Engineering》2002,22(9-12):1193-1197

The paper is devoted to the investigation of seismic response of the masonry structure and describes experiences with modelling of boundary conditions during the test of large heavy model on 6DOF shaking table. The main aim of the research was how to increase dynamic resistance capacity of old masonry buildings including the medium and strong seismic effects. The results of theoretical and numerical analyses are compared including initial forecasting calculations made before any test started. The emphasis is given to the boundary conditions reached during the excitation of the large masonry model via shaking table. Strengthening and retrofitting procedures and their effects are discussed when special fibre mortar is used for repair and strengthening of masonry parts of structure.  相似文献   

我国医学地理研究的主要进展和展望   总被引：11，自引：3，他引：11  

谭见安  李日邦 《地理学报》1990,45(2):186-201

简述了我国医学地理学的历史发展,60年代以来是我国医学地理发展最迅速的时期。特别在地方病、癌症等疾病的地理分布规律、地理流行特点、生态学特性、环境病因、病区环境改善和地理制图等方面取得了较显著的进展。并综合国内外的发展略述了医学地理的性质和任务。本文依医学地理的主要研究领域:疾病地理、健康地理、保健地理、医学地理制图等扼要地阐述了所获得的主要研究成果,其中有些受到国内外的广泛重视和关注。  相似文献   

北黄海菲律宾蛤仔帕金虫汉行病害的研究   总被引：1，自引：0，他引：1  

梁玉波  张喜昌等 《海洋与湖沼》2001,32(5):502-511

2000年7月－11月，对我国北黄海沿岸滩涂增养殖的菲律宾蛤仔Ruditapes philippinarum大规模死亡进行了研究，并对病害暴发与温度、盐度的相关性进行了探讨。利用FTM培养和组织切片方法对病害流行海域的菲律宾蛤仔进行了检测。结果表明，蛤仔体内寄生了大量病原帕金虫Perkinsus sp，感染率为20％－100％，感染强度为3－3565936cell/ind或2－1670615cell/g组织。感染强度与蛤仔大小有关，个体越小，感染程度越轻。经感染试验，进一步确定了帕金虫大量繁殖是引起蛤仔大规模死亡的原因。病害始于7月下旬，止于10月下旬；最初暴发于庄河栗子房海域，尔后逐渐向东西两侧海域蔓延。病害暴发时要主要受温度影响，高于20℃易于暴发帕金虫病害；流行范围主要受盐度影响，盐度为20－32海域适宜帕金虫病害的流行。  相似文献   

新疆喀什地区新型石木结构房屋的模型抗震试验          下载免费PDF全文

张小平  陈平  赵冬  周铁钢 《地震工程学报》2008,30(1):42-45

对新疆喀什地区出现的新型石木结构房屋进行了1/4比例模型的地震反应试验的设计.概述了模型振动台试验方法,了解了此类结构的破坏形态,并对试验结果进行了初步分析,同时对结构进行了初步抗震性能评价.结果表明结构能够满足小震不坏、中震可修、大震不倒的抗震设防要求.  相似文献   

西藏大骨节病区的地理环境特征   总被引：6，自引：1，他引：5  

杨林生  吕瑶  李海蓉  李永华  李顺江  王五一  谭见安 《地理科学》2006,26(4):466-471

西藏90%以上的大骨节病县分布在高山温带环境中,病区最暖月平均气温在10~18℃之间,≥0℃日数在180~350天之间;病区集中分布在喜马拉雅山与冈底斯山和念青唐古拉山之间以及横断山北段山间地带的山区或高山谷地地区,病县山地、丘陵占78.4%,非病县山地、丘陵面积占66.7%;就海拔高度而言,病区主要分布在3600~4000m之间;病区涉及多种类型的耕作土壤,其中酸性棕壤和暗棕壤、灰褐土和石灰性褐土、褐土性土等淋溶、半淋溶土壤类型是大骨节病集中分布区;在高山土壤类型中病区趋于分布在典型亚高山草甸土和山地灌丛草原土地带,而亚高山草原土带相对较少。西藏大骨节病区地理环境特征既与内地大骨节病区有很强的相似性,又因其独特的地域分异格局而具特殊性。  相似文献   

Seismic microzoning from synthetic ground motion earthquake scenarios parameters: The case study of the city of Catania (Italy)     

《Soil Dynamics and Earthquake Engineering》2016

The city of Catania (Italy) in the South-Eastern Sicily has been affected in past times by several destroying earthquakes with high values of estimated magnitude. The seismogenic area to the south of Volcano Etna, known as Iblean Area, is placed between the African and the Euro-Asiatic plates on the west of the Ibleo-Maltese escarpment, to the south of the Graben of the Sicilian channel and on the east of the overlapping front of Gela. Basing on the seismic history of Catania, the following earthquake scenarios have been considered: the “Val di Noto” earthquake of January 11, 1693 (with intensity X-XI on MCS scale, magnitude M_W=7.41 and epicentral distance of about 13 km); the “Etna” earthquake of February 20, 1818 (with intensity IX on MCS scale, magnitude M_W=6.23 and epicentral distance of about 10 km). The soil response analysis at the surface, in terms of time history and response spectra, has been obtained by 1-D equivalent linear models for about 1200 borings location available in the data-bank of the central area of Catania of about 50 km², using deterministic design scenario earthquakes as input at the conventional bedrock.Seismic microzoning maps of the city of Catania have been obtained in terms of different peak ground acceleration at the surface and in terms of amplification ratios for given values of frequency.  相似文献