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211.
Although marine protected areas can simultaneously contribute to biodiversity conservation and fisheries management, the global network is biased toward particular ecosystem types because they have been established primarily in an ad hoc fashion. The optimization of trade‐offs between biodiversity benefits and socioeconomic values increases success of protected areas and minimizes enforcement costs in the long run, but it is often neglected in marine spatial planning (MSP). Although the acquisition of spatially explicit socioeconomic data is perceived as a costly or secondary step in MSP, it is critical to account for lost opportunities by people whose activities will be restricted, especially fishers. We developed an easily reproduced habitat‐based approach to estimate the spatial distribution of opportunity cost to fishers in data‐poor regions. We assumed the most accessible areas have higher economic and conservation values than less accessible areas and their designation as no‐take zones represents a loss of fishing opportunities. We estimated potential distribution of fishing resources from bathymetric ranges and benthic habitat distribution and the relative importance of the different resources for each port of total catches, revenues, and stakeholder perception. In our model, we combined different cost layers to produce a comprehensive cost layer so that we could evaluate of trade‐offs. Our approach directly supports conservation planning, can be applied generally, and is expected to facilitate stakeholder input and community acceptance of conservation.  相似文献   
212.
汶川8.0级地震所引发的防震减灾工作启示   总被引:3,自引:3,他引:0  
1966年邢台地震和2008年汶川8.0级地震,对中国防震减灾事业的方针政策已经产生和正在产生深刻影响。汶川8.0级地震的惨痛教训进一步说明,在地震预报不过关或还不可靠的前提下,震灾预防是减轻地震灾害的最有效途径。汶川地震的灾情和云南省减隔震技术研究应用、农村民居抗震、城中村改造三大工程加速了中国防震减灾结构的调整——应把建构筑物抗震设防摆在更重要的位置。  相似文献   
213.
Wang L  Tang A 《Chemosphere》2011,82(5):782-785
The reaction mechanisms of dibenzo-p-dioxin (DD) and 2,3,7,8-TCDD with OH radical have been studied using density functional theory calculations. Under the atmospheric conditions, ca 42% of DD + OH reaction proceeds as formation of DD − OH-β adduct, which will react with O2 slowly; while the rest will proceed as formation of DD − OH-γ adduct, which will decompose to the substituted phenoxy radical P1 by the fused-ring C-O bond cleavage. For 2,3,7,8-TCDD + OH, the reaction will predominantly form the substituted phenoxy radical P2. The reaction mechanisms are drastically different from the peroxy mechanism for the atmospheric oxidations of benzene and dibenzofuran.  相似文献   
214.
为探索运动对2,3,7,8-四氯二苯并二噁英(2,3,7,8-TCDD)持续暴露大鼠肝脏氧化应激的影响,本研究将7周龄雄性SD大鼠适应性喂养1周后,随机分为对照(NC)、运动对照(EC)、染毒1(NT1)、运动染毒1(ET1)、染毒2(NT2)、运动染毒2(ET2)、染毒3(NT3)、运动染毒3(ET3)、染毒4(NT4)及运动染毒4(ET4)共10组。染毒组(NTs、ETs)腹腔注射TCDD(溶于玉米油),对照组及各染毒组首次剂量依次为0、0.4、1.6、6.4、25.6μg·kg~(-1)(以单位体重计),之后每周给予上述剂量的21%作为维持剂量,持续染毒8周;运动组尾部负重5%游泳,每周5 d,每次30 min。实验结束取材,测定血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)、肝组织超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)、活性氧(ROS)含量。结果显示:1)染毒可升高各染毒组大鼠血清AST活性及NT4组大鼠血清ALT活性,增加NT2、NT3组肝脏MDA含量,而降低NT1、NT2组大鼠血清ALT活性;2)运动可升高大鼠血清AST及ALT活性,增加大鼠肝组织GSH-Px活性;3)运动可升高染毒大鼠血清AST活性(T1剂量),降低染毒大鼠血清ALT活性(T1剂量),降低染毒大鼠血清AST活性(T3剂量),升高染毒大鼠血清ALT活性(T3、T4剂量),增加染毒大鼠肝组织SOD活性(T2、T3剂量)、CAT活性(T1、T2、T3剂量)及GSH-Px活性(T2、T3、T4剂量),降低染毒大鼠肝组织MDA含量(T2、T3、T4剂量)及ROS含量(T1、T3剂量)。结果表明,2,3,7,8-TCDD持续暴露8周可引起大鼠肝细胞氧化应激损伤,并产生剂量依赖效应;而有氧运动可增加2,3,7,8-TCDD持续暴露(T2、T3剂量)大鼠肝组织抗氧化酶活性,有效降低氧化应激损伤而减轻肝毒性。  相似文献   
215.
A method employing solid phase extraction followed by gas chromatography-mass spectrometry with negative chemical ionization has been developed for determination of ultratrace concentrations of perfluoroalkyl carboxylic acids in river water. The effects of the experimental parameters, such as the pH, additions of NaCl and an ion-pairing agent (tetraethylammonium bromide) and the kind of the elution agent, on the efficiency of the test acid extraction have been studied. The analyte extraction recoveries and the limits of detection and determination have been found. The method developed has been tested on determinations of perfluoroalkyl carboxylic acids in the waters of the two largest Czech rivers, Vltava and Labe (Elbe). The best extraction results have been attained without any alteration of the sample pH, with an addition of tetrabutylammonium bromide (a concentration of 50 μg mL−1 in the sample) and using methanol as the elution agent. Under these conditions, the recoveries of the test acids in the spiked real samples are within ranges from 60% to 104% and 53% to 111% for analyte concentration levels of 1.40 ng mL−1 and 0.14 ng mL−1, respectively, depending on the lengths of the perfluorinated chains of the acids. In general, the recovery decreases with increasing length of this chain. The method developed exhibits very low limits of detection and determination and the results are fully comparable with those obtained when using more expensive HPLC-MS/MS instrumentation. Typical values amount to tenths to tens of pg mL−1 and units to one hundred pg mL−1 for the limits of detection and determination, respectively; the measuring sensitivity increases with increasing length of the analyte chain. The analyzes of real samples from the Vltava and Elbe rivers have demonstrated that the results obtained are similar to the values published for contamination of the Elbe and other rivers in western and central Europe. The concentrations determined are of the order of units to tens of pg mL−1 and the C8-C10 acids occur most often.  相似文献   
216.
番茄中8-羟基喹啉铜残留量的液相色谱测定   总被引:3,自引:0,他引:3  
建立了番茄中8-羟基喹啉铜[Cu(HQ)2]的超声波辅助溶剂提取—反相离子对高效液相色谱法的残留分析方法,该方法使用XBridge C18色谱柱和可变波长紫外检测器,并以水相磷酸盐缓冲溶液—乙腈(体积比为60∶40)作流动相,流速为0.6 ml/min,检测波长为250 nm,保留时间为4.66 min。本方法的线性相关系数为0.998,回收率在76.3%~92.2%内,RSD≤5.5%。方法的检出限为0.06 mg/kg。  相似文献   
217.
四川都江堰市地处龙门山主山前边界大断裂上,在汶川8.0级地震烈度分布图中属于Ⅸ度区,是地震受灾最严重的城市之一。作为城市生命线的天然气供应链在本次地震中遭遇了一定的破坏。通过对都江堰市天然气系统的基本构成、震害情况以及应急救灾过程等的调查与整理,对都江堰燃气系统中门站、CNG加气站、中压配气管网及低压配气支管各组成部分在地震中的震害情况进行了分析,对震后的应急处置措施、供气恢复策略及灾后重建工作进行了综述,总结了汶川地震中都江堰天然气系统的应灾经验及救灾环节中的不足之处,并就如何提高燃气系统的抗震应灾能力提出建议。  相似文献   
218.
苗爱梅  陈康 《灾害学》2010,25(3):77-80
通过对汶川8.0级地震发生后西安、成都地区(地震烈度为Ⅵ~Ⅶ度区)的高层建筑震害调查,以某小区震后建筑物非承重墙体裂缝为实例,给出了高层建筑震害易发生的部位和楼层,分析了非承重墙体裂缝产生的原因。震害调查表明:汶川地震中,在抗震设防烈度为Ⅵ~Ⅷ度区,当地震烈度为Ⅵ~Ⅶ度时,非承重墙抗震性能的表现不尽如人意。提出了应对非承重墙体制定设防目标,且非承重结构构件的抗震设防目标应与主体结构设防目标相适应,使建筑结构设计,对非承重墙的抗震设防有据可依,使灾后有可能对设计与施工的质量进行评估,通过有区别地加强非承重墙的抗震构造措施,减小建筑物的震害损失。  相似文献   
219.
It was observed that the atomic fluorescence emission due to signal during the determination of As(Ⅲ) in the mixture of As(Ⅲ) and As(V) could has a 10% to 40% of fluorescence emission As(V). Besides, interferes from heavy metals such as Pb(Ⅱ), Cu(Ⅱ) can cause severe increase of the signals as compared to the insignificant effects caused by Cd(Ⅱ), Zn(Ⅱ), Mn(Ⅱ) and Fe(Ⅲ). On the basis of further studies, the masking agent of 8-hydroxyquinoline was used as an efficient agent to eliminate interference of As(V) emission and the heavy metal of Cu^2+ and Pb^2+ in the measurements of arsenic species, After a series standard additions and CRM researches, a sensitive and interference-free analytical procedure was developed for the speciation of arsenic in samples of porewaters and sediments in Poyang Lake, China.  相似文献   
220.
A modern challenge for conservation biology is to assess the consequences of policies that adhere to assumptions of stationarity (e.g., historic norms) in an era of global environmental change. Such policies may result in unexpected and surprising levels of mitigation given future climate‐change trajectories, especially as agriculture looks to protected areas to buffer against production losses during periods of environmental extremes. We assessed the potential impact of climate‐change scenarios on the rates at which grasslands enrolled in the Conservation Reserve Program (CRP) are authorized for emergency harvesting (i.e., biomass removal) for agricultural use, which can occur when precipitation for the previous 4 months is below 40% of the normal or historical mean precipitation for that 4‐month period. We developed and analyzed scenarios under the condition that policy will continue to operate under assumptions of stationarity, thereby authorizing emergency biomass harvesting solely as a function of precipitation departure from historic norms. Model projections showed the historical likelihood of authorizing emergency biomass harvesting in any given year in the northern Great Plains was 33.28% based on long‐term weather records. Emergency biomass harvesting became the norm (>50% of years) in the scenario that reflected continued increases in emissions and a decrease in growing‐season precipitation, and areas in the Great Plains with higher historical mean annual rainfall were disproportionately affected and were subject to a greater increase in emergency biomass removal. Emergency biomass harvesting decreased only in the scenario with rapid reductions in emissions. Our scenario‐impact analysis indicated that biomass from lands enrolled in the CRP would be used primarily as a buffer for agriculture in an era of climatic change unless policy guidelines are adapted or climate‐change projections significantly depart from the current consensus.  相似文献   
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