坛紫菜叶状体营养细胞与生殖细胞叶绿素荧光特性比较     

李家富  张涛  陆勤勤  朱建一  沈宗根  刘兆普  王长海 《海洋科学》2013,37(3):82-86

利用叶绿素荧光技术对坛紫菜(Porphyra haitanensis)叶状体营养细胞和生殖细胞的光能利用特性进行了比较。结果表明:坛紫菜叶状体营养细胞和雌性生殖细胞的实际量子效率(ΔF/Fm′)差异不明显,但显著高于雄性生殖细胞;快速光曲线测定表明雌、雄藻体营养细胞的最大相对电子传递速率(rETRmax)相近,但显著高于雄性生殖细胞;不同生殖细胞半饱和光强(Ik)无显著差异;在生长光强下,营养细胞和雌性生殖细胞rETR、光化学猝灭(qP)和非光化学猝灭(NPQ)差异不明显,而雄性生殖细胞rETR、qP等荧光参数均显著低于营养细胞和雌性生殖细胞。本文表明坛紫菜叶状体营养细胞和雌性生殖细胞具有较高的光能利用能力,能够将吸收的光能多数用于电子传递,而雄性生殖细胞对光能的利用能力较低。  相似文献   

Morphodynamic implications for shoreline management of the western-Mediterranean sector of Egypt     

Omran E. Frihy 《Environmental Geology》2009,58(6):1177-1189

Although the western-Mediterranean coast of Egypt between Sallum and Alexandria, ~550 km long, has maintained a considerable equilibrium throughout history, developers have built traditional protective structures in an effort to form sheltered recreational beaches without taking into consideration its geomorphologic characteristics, coastal processes and their harmful impact on the coastal environment and human safety. The improper practices in this environmentally valuable region have induced us to undertake an initiative to carry out a morphodynamic analysis to provide a framework for understanding the relationship between coastal morphology and the prevailing dynamic forces. Based on the degree of natural protection or wave sheltering, the study shoreline can be categorized into four distinct morphotypical stretches: (1) high-energy wave-exposed shores and the outer margins of the rocky headlands, (2) moderate to high wave-energy beaches along semi-exposed embayments and bays mostly downdrift of the rocky headlands, (3) low-wave energy at semi-exposed headland lee-sided and pocket beaches, and (4) calm wave-sheltered enclosing water basins for safe anchorages, moorings and recreation beaches. The results deducted will have practical applications for shoreline management initiatives regarding sustained sites suitable for future beachfront development such as safe swimming conditions, sport facilities, water intakes and sheltered areas for vessels. In addition, benefits realized by the understanding of the morphodynamic processes would enhance our awareness of the significance of the role of western coast morphodynamics in supporting sustainable development via shoreline management. As far as sustainability is concerned, the selection of appropriate sites would help avoiding or minimizing the formation of the hard structures needed for creating safe recreation beaches. On a national scale, results reached could provide reliable database for information that can be used in establishing a sustainable shoreline management plan, which is, in turn, an essential part when implementing an Integrated Coastal Zone Management Plan for this region of attraction.  相似文献   

深穿透地球化学迁移机理与方法技术研究新进展   总被引：2，自引：0，他引：2  

唐金荣  吴传璧  施俊法 《地质通报》2007,26(12):1579-1590

系统地论述了近年来国际勘查界在深穿透地球化学迁移机理与方法技术方面的新进展。重点介绍了元素垂向迁移的新模型和新理论,包括"还原囱"模型、"雷暴电池"模型、泵压效应机制等。叙述了国内外深穿透地球化学的研究成果,主要包括加拿大矿业研究组织(CAMIRO)资助的国际合作项目、澳大利亚景观环境与矿产勘查联合研究中心(CRC LEME)的试点研究及其他国家的研究工作。在此基础上,对影响选择性提取技术的关键因素进行了探讨,认为选择性提取技术的战略选择和对单一"目标矿物"的选择性提取比较复杂,在一定程度上受土壤形成过程及其理化性质如pH、Eh等因素的影响,此外还与提取液的浓度、采样深度和提取条件与过程的控制等有关。  相似文献   

Stochastic analysis of neutrally stratified cirrus layer     

K. Ivanova  T.P. Ackerman   《Journal of Atmospheric and Solar》2007,69(17-18):2265

Two cirrus cloud systems observed during the winter of 2001 at the Southern Great Plains site of the Atmospheric Radiation Measurements program in Oklahoma, USA are studied because of the distinct neutrally stratified layers formed within the clouds. Observations are obtained with 35 GHz millimeter-wave radar and backscattering cross-section η(t) signals within radar-reflectivity restricted sublayers of the clouds are analyzed. The neutrally stratified layers of cirrus clouds are known to be associated with the existence of generating cells. The statistics of radiative properties within the neutrally stratified layers is obtained to be non-Gaussian and time-dependent. The purpose of this research is to derive a model of the cloud-generating cells layer in cirrus based on the statistics of observations. The Fokker–Planck equation approach provides suitable framework to treat non-Gaussian, time-dependent probability density functions (pdfs) such as those found for the η(t) signals. It is shown that the deviations from Gaussianity of radiative properties of the neutrally stratified generating cells layer in cirrus can be modeled by linear stochastically perturbed dynamics with multiplicative noise statistics. Because the multiplicative noise is often identified with state-dependent variations of stochastic feedbacks from unresolved system components it is expected that derived stochastic model will be useful for parameterization of cirrus in global circulation models (GCMs).  相似文献   

可口革囊星虫(Phascolosoma esculenta)重组铁蛋白富集Pb²⁺等重金属特性和功能研究   总被引：1，自引：1，他引：0  

初双双  张云云  苏倡  王颖  陈丽萍  周君  张迪骏  司开学  苏秀榕 《海洋与湖沼》2015,46(6):1358-1364

利用可口革囊星虫重组铁蛋白富集Pb²⁺、Fe³⁺、Cd²⁺、Cr³⁺、Cu²⁺、Mn²⁺、Sn²⁺和Zn²⁺等8 种重金属离子后, 通过透射显微镜和傅里叶红外光谱测定蛋白的超微结构变化和内部基团特性。以 天然的马脾铁蛋白为对照, 观察重组铁蛋白与天然铁蛋白的差别。结果显示, 重组铁蛋白富集Pb²⁺ 和其它7 种重金属离子后蛋白体积大小与重金属离子种类直接相关。重组铁蛋白相对天然铁蛋白来 说在富集不同种类重金属离子后, 除了非特异性酰胺特征峰和蛋白特征峰外, 还出现一些专门富集 某些重金属离子的特异基团, 如:-CH₃、-CH₂-、-CH-、-NH-、-SO₃-、-COOH、-S=S-和-C-S-C 等。 通过细胞实验进一步验证了铁结合蛋白能够通过富集重金属离子Pb²⁺来保护小鼠成骨前体细胞 MRC3T3-E1, 使细胞的死亡率明显降低(P<0.05).  相似文献   

牛胎盘中肝细胞生长因子的生物学特性     

郎刚华  王勇  刘万顺  陈西广  张振宇  李兴诗 《中国海洋大学学报(自然科学版)》1998,(2)

实验研究来源于牛胎盘的肝细胞生长因子的生物学特性。将新鲜牛胎盘匀浆后经盐析、亲和层析、超滤和离子交换层析可以纯化到一种肝细胞生长因子。实验采用３Ｈ－ＴｄＲ掺入细胞ＤＮＡ的量来表示肝细胞生长因子促进细胞ＤＮＡ合成的作用,用液体闪烁计数来探测３Ｈ的放射性。结果表明：该因子对原代培养的大鼠肝细胞、肾细胞的ＤＮＡ合成都有刺激作用,而且也能刺激原代培养的人胎肝细胞的ＤＮＡ合成。但对传代培养的小鼠腹水Ｓ１８０细胞的ＤＮＡ合成则有抑制作用。另外,此因子对热不稳定,经热处理之后,其对大鼠肝细胞的刺激作用和对小鼠腹水Ｓ１８０细胞的抑制作用都降低了。  相似文献   

Cu₂₊和Zn₂₊对罗氏沼虾体外培养肌细胞的影响     

王军霞  刘金  王维娜  杨波  翟宗昭 《海洋科学》2005,29(1):38-43

研究了L-15和M199两种培养基对体外培养罗氏沼虾(Macrobrachium rosenbergii)肌细胞生长的差异。结果表明，L-15较M199更有利于罗氏沼虾肌细胞的生长。分别测定了不同浓度的Zn^2 (0～160ug／L)和Cu^2 (0～10ug／L)对罗氏沼虾离体培养肌细胞的影响，通过MTT法测定肌细胞的增殖．NBT法测定肌细胞活性氧的产生，结果表明，Zn^2 浓度为80～120ug／L时细胞的增殖效果较好，细胞内活性氧的产生最少；Cu^2 浓度为8ug／L时细胞的增殖达到最大，活性氧产生最少。  相似文献   

Dynamic response of a flexible pavement submitted by impulsive loading     

B. Picoux  A. El AyadiC. Petit 《Soil Dynamics and Earthquake Engineering》2009

The present paper introduces results from measurements on site using a falling weight deflectometer (FWD). This apparatus is used for non-destructive testing of damaged pavement in order to estimate the elastic modulus of each layer. The basin of deflection induced by a controlled load can be determined with precision and can reflect the behavior of the pavement structure. The interpretation of data generated by FWD leans on inverse analysis processes. Data from FWD combined with the thickness of layers inform on the evolution of the Young's modulus of each layer of the structure along the studied road profile. This information can be also used to estimate its lifespan and possible repairs to be carried out.  相似文献   

基于MapInfo的地震烈度发生概率计算方法   总被引：1，自引：0，他引：1  

陈鲲  高孟潭 《中国地震》2008,24(4)

本文详细介绍使用MapBasic语言编制,基于离散化后预测单元各震级档的地震发生概率,计算场点地震烈度发生概率的程序。通过交换求和方式,简化了计算程序。以四川省为例,计算四川区域范围内地震烈度年发生概率,结果以网格点(0.1°×0.1°网格)和乡镇形式给出。计算结果直接用于GIS数据库平台的管理,为地震危险性分析程序与GIS的结合打下一定的基础。  相似文献