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Flagella, the basic locomotive organ in algae, as well as bacteria and some cells of animals or high plants, would be damaged
in the well stirred mass culture due to the strong forces caused by the fast mixing impellers. The dynamic regeneration of
the flagella in deflagellatedDunaliella salina was studied microscopically by using a bench-top flat-bottom photobioreactor. The results showed that 90 minutes was necessary
for the repair of flagella, after which half of the cells became motile as their flagella generated within 120 minutes and
nearly all of the cells could swim freely within 180 minutes.
Contribution No. 3503 from the Institute of Oceanology, Chinese Academy of Sciences. 相似文献
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利用python程序语言开发了基于百度地图导航服务的批量路径时间查询平台,并结合最邻近设施时间和累积机会成本方法度量了居住单元与中心商业区（CBD）、与行政服务中心、与大型医院、与火车站、与飞机场的可达性;然后,着重对比分析了2种公交模式（有/无地铁）下公共服务设施可达性的差异。实验结果表明：① 与基于ArcGIS网络分析法等传统方法相比,基于“门到门”互联网路径规划服务API方法计算的出行时间成本能够较为精确、便捷地用于度量公共服务设施的可达性,避免了人工构建复杂路网数据集的工作量,而且更具时效性;② 融入地铁网络的公交模式不同程度上提升了居住单元至公共服务设施的可达性,尤其是地铁沿线“廊道”以及重要交通设施（如地铁站点）邻近区域最为显著;③ 居住单元至邻近CBD的可达性变化显著集中于0~30 min,30 min时间阈值内公交（有地铁）模式下累计的人口和面积分别是公交（无地铁）模式的1.7倍和2.2倍;④ 居住单元至邻近火车站的可达性变化显著集中于0~30 min以及30~60 min,30 min时间阈值内公交（有地铁）模式下累计的人口和面积分别是公交（无地铁）模式的8.9倍和3.0倍,60 min时间阈值内累计的人口和面积分别是公交（无地铁）模式的1.5倍和1.9倍;⑤ 居住单元至邻近飞机场的可达性变化显著集中于60~90 min以及90~120 min,90 min时间阈值内公交（有地铁）模式下累计的人口和面积分别是公交（无地铁）模式的12.6倍和6.6倍,120 min时间阈值内累计的人口和面积分别是公交（无地铁）模式的2.0倍和3.6倍;⑥ 居住单元至所属行政中心、至邻近大型医院的可达性在各个时间间隔及阈值范围内亦有相应幅度的改善。此外,运用本文的技术方法还可获得更完整、真实的其他交通模式（如汽车、电动车、自行车、步行等）接入城市公共服务设施的情形,为进一步研究非汽车模式下城市公共服务设施的可达性提供参考,促进城市公共交通可持续性的发展。 相似文献
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快速城镇化导致我国城市消防应急服务基础设施与城市发展不同步的问题日益凸显,城市消防救援覆盖率评估是提升消防服务质量与优化消防资源配置的重要手段。本文提出一种基于实时路况的城市消防救援覆盖率评估模型,通过考虑消防站管辖区域的空间限制,在2020年9月连续三周时间内利用高德地图API获取消防站到达历史火灾事件的实时出行救援时间,对南京市消防救援覆盖率的时空模式进行分析与挖掘。结果显示：① 南京城市火灾密集区域（简称火灾密集区）消防站的平均出行救援时间约10 min,非火灾密集区约16 min,均比国家规定的5 min到达时间标准明显要长,导致南京市消防站在5 min到达标准下的覆盖率仅为8.2%;② 由于南京火灾密集区消防站的平均行车救援距离仅为非火灾密集区的37%,导致火灾密集区火灾事件等待救援时间明显低于非火灾密集区,尤其火灾密集区西南部、东北部及部分消防站周边火灾事件等待救援时间相对较短,但南京全区火灾事件等待救援时间在5 min以内的比例不足7%,且等待救援时间在5~10 min之间的短距离火灾事件受早晚交通出行高峰期交通拥堵影响最大;③ 南京市消防站救援覆盖率受早晚交通出行高峰影响呈现早晚交通出行高峰期明显低于其他时段的“W”形变化模式,火灾密集区消防站在5 min到达标准下的救援覆盖率从非交通出行高峰期的11.5%降低到交通出行高峰期的8.4%,而非火灾密集区从6.1%降低到5%,火灾密集区东南部石门坎与东山交界区域和北部汉中门与迈皋桥周边区域早晚交通出行高峰时段等待救援时间超过15 min的火灾事件比非交通出行高峰时段明显增多;④ 在5 min到达标准下,南京市消防站救援覆盖率“W”形模式波动最小,10 min到达标准下的平均覆盖率为43.5%且波动最明显,15 min到达标准下的平均覆盖率达到75%。最后根据分析结果给出了南京市消防未来建设发展意见。 相似文献
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Most studies on Haematococcus pluvialis have been focused on cell growth and astaxanthin accumulation;far less attention has been paid to cell cycles and proliferation patterns.The purpose of this study was to clarify cell cycles and proliferation patterns in H.pluvialis microscopically using a camera and video recorder system.The complicated life history of H.pluvial i s can be divided into two stages:the motile stage and the non-motile stage.All the cells can be classifi ed into forms as follows:motile cell,nonmotile cell,zoospore and aplanospore.The main cell proliferation,both in the motile phase and non-motile phase in H.pluvialis,is by asexual reproduction.Under normal growth conditions,a motile cell usually produces two,sometimes four,and exceptionally eight zoospores.Under unfavorable conditions,the motile cell loses its fl agella and transforms into a non-motile cell,and the non-motile cell usually produces 2,4 or 8 aplanospores,and occasionally 20–32 aplanospores,which further develop into non-motile cells.Under suitable conditions,the non-motile cell is also able to release zoospores.The larger non-motile cells produce more than 16 zoospores,and the smaller ones produce 4 or 8 zoospores.Vegetative reproduction is by direct cell division in the motile phase and by occasional cell budding in the non-motile phase.There is,as yet,no convincing direct evidence for sexual reproduction. 相似文献
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信息化的不断发展,使气象预报的精确度越来越依赖更多更详细的自动站数据;目前全区有92个大监自动站和1200多个区域站的多种报类每半小时定时上传,如果遇到天气过程则是每10分钟加密上传,能否在国家局考核时效内迅速处理并上传单站合并数据,对于传输质量以及录入数据信息再利用起着至关重要的作用。为此,介绍的系统以delphi为编程平台,采用多线程技术使之能够多路同时并发快速处理单站数据,并取得良好的运行效果。 相似文献
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Nephroselmis gaoae sp.nov.is described on the basis of light and electron microscope observations ofcultured material originally collected and isolated from seawater of Jiaozhou Bay,Qingdao,China.Theperiplasts on the cell body and flagella are covered by five types of scales,two types on the flagella andthree on the body.Among these,the morphology and the number of spines of large stellate body scalesdiffer remarkably from those of previously described species of Nephroselmis.Apart from these,the unusualfine structure of the eyespot(stigma)is very characteristic.As in the other species of Nephroselmis,theeyespot lies immediately under the two-membraned chloroplast envelope;unlike the others,however,it isnot composed of a number of osmiophilic globules,but consists of about 14 curved rod-shapedosmiophilic bodies arranged loosely and randomly.This feature distinguishes the present new species notonly from the other species of Nephroselmis but also from the other motile algal species,the eyespots struc-ture 相似文献
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Nephroselmis gaoae sp. nov. is described on the basis of light and electron microscope observations of cultured material originally collected
and isolated from seawater of Jiaozhou Bay, Qingdao, China. The periplasts on the cell body and flagella are covered by five
types of scales, two types on the flagella and three on the body. Among these, the morphology and the number of spines of
large stellate body scales differ remarkably from those of previously described species ofNephroselmis. Apart from these, the unusual fine structure of the eyespot (stigma) is very characteristic. As in the other species ofNephroselmis, the eyespot lies immediately under the two-membraned chloroplast envelope; unlike the others, however, it is not composed
of a number of osmiophilic globules, but consists of about 14 curved rod-shaped osmiophilic bodies arranged loosely and randomly.
This feature distinguishes the present new species not only from the other species ofNephroselmis but also from the other motile algal species, the eyespots structure of which had been previously described.
Contribution No. 2316 from the Institute of Oceanology, Chinese Academy of Sciences.
This paper was presented at the XIVth International Seaweed Symposium held in Brittany, France, 1992. 相似文献
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This study investigated the cytotoxicity of gemcitabine using the marine ciliate Euplotes vannus as the test organism.The median lethal concentrations(LC_(50) values)were determined using acute toxicity tests within an exposure time of 30 min with 0,6,12,24,and 48 mg mL~(-1) gemcitabine.The median inhibition effect(IC_(50) value)on the growth of the ciliate cells was examined using chronic toxicity tests within 5 days(120 h)after exposure for 30 min with 0,0.7,3.5,7,and 14 mg mL~(-1) gemcitabine.The 30-min LC_(50)value was 10.66~-mg mL ~1.The LC_(50) values decreased with increasing exposure times and well fitted to the toxicity curve equation LC_(50)=10.93+28.4e~(-0.19t)(R~2=0.93;P0.05,t=exposure time).The IC_(50) value for growth rates was 7.05 mg mL~(-1),and the inhibition effect on growth rates well fitted to the model equation r_%=0.8681e~(-0.0782Cgem)(r_%means growth rate with inhibition by gemcitabine,C_(gem) means concentrations of gemcitabine,R~2=0.99 and P0.05).The LC_(50) values of a wide range of gemcitabine concentrations could therefore be predicted for any given exposure time.These results suggest that the clinical dose of gemcitabine(20 mg mL~(-1))was higher than the 30-min LC_(50) value,which was almost the same as the 6-min LC_(50) value(19.88 mg mL~(-1))for E.vannus cells.The results also demonstrate that E.vannus can be used as a robust test organism for bioassays of chemotherapeutic drugs during short exposure periods. 相似文献
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手机用户上网时段研究与预测对手机用户行为与模式分析、网络服务内容设计、网络黏性与心理、移动互联商业智能等具有重要意义。本文结合Markov模型和关联规则模型,提出一种手机用户上网时段的混合Markov预测方法——Lift-Markov（LM）方法,并采用中国某城市4G手机用户流量上网产生的流量收费数据进行实验验证与分析。研究发现：该实验区域37.66%的手机用户个体存在明显的以天为周期的周期性特性;本文所提出的LM方法在10、20、30、40、50、60 min间隔时的平均预测准确率都优于Markov模型和Mostvalue模型,其中在60 min间隔时能达到79.75%的平均准确率,优于Markov模型（74.64%）和Mostvalue模型（64.44%）;LM方法的预测准确率分布相比于其他2种模型都要窄,而且密度分布峰值最高、标准差最小,说明本文方法对人群的上网时段预测准确率较为集中与稳定,具有较好的预测性能。 相似文献
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利用Okada模型计算2018-01-23 09:31（UTC）阿拉斯加湾7.9级地震引发的海啸的初始场信息，利用COMCOT模型模拟海啸传播。比较海啸首波振幅和到达时间模拟值与实测值显示，振幅差异在4 cm以内，时间差异在4 min以内。模拟结果与观测资料吻合，揭示阿拉斯加地震引发的海啸强度弱，同时反映海啸初始场参数的选择合理有效，海啸模拟计算结果真实可靠。 相似文献
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1 INTRODUCTION The introduction of invasive marine species into new environments by ship’s ballast water, by attaching to ships’ hulls or via other vectors has been recognized as one of the four major threats to the world’s oceans by Global Environment… 相似文献
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A bloom of the dinoflagellate Scrippsiella trochoidea was detected for the first time in inner Tolo Harbor,Hong Kong in 2 000. Water samples were collected at eight stations along a transect passing through a red tide patch for microscopic analysis of phytoplankton composition and high-performance liquid chromatography(HPLC) analysis of phytoplankton pigments. During the bloom,the density of dinoflagellates was 1.1×106 cells L-1 within the patch and 8.6×105 cells L-1 outside the patch where the phytoplankto... 相似文献
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利用终端位置时空转移概率预测通讯基站服务用户规模 总被引：1，自引：0，他引：1
基站服务用户数的预测对通信基站的空间位置选取、通讯服务带宽的配置优化等有重要作用,并为城市公共安全管理方面中的人群聚集预警与群体事件预防提供辅助决策支持。本文利用海量手机轨迹数据,运用时空转移概率定量化描述城市内不同区域间人群流动的时空特性,结合马尔可夫链和贝叶斯定理,构建手机用户群体在基站间的时空转移概率模型,并以此提出一种城市区域尺度上的基站服务用户数预测方法。利用湖北省某城市长达30 d的手机轨迹数据进行模型训练与预测方法验证,实验结果表明：在时间粒度为60 min时,本文提出的方法对8-22时各时段基站服务用户数预测准确率都大于94.8%;在不同时间粒度下对比本文方法、Castro模型、移动平均法,发现在时间粒度大于20 min时,本文方法预测准确率高于另外两种方法。 相似文献
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Ｂｉｖａｌｖｅｓｈａｖｅｔｒａｎｓｌｕｃｅｎｔｔｈｉｎｍｅｍｂｒａｎｅｓ—ｔｈｅｇａｓｔｒｉｃｓｈｉｅｌｄｃｏｖｅｒｓｏｎｔｈｅｌｅｆｔｏｆｔｈｅｐｏｓｔｅｒｉｏｒｓｔｏｍａｃｈｗａｌｌｓ;ｔｈｅｈｅａｄｏｆｔｈｅｃｒｙｓｔａｌｌｉｎｅｓｔｙｌｅｈｏｕｓｅｄｉｎｔｈｅｓｔｙｌｅ ｓａｃｉｓｒｏｔａｔｅｄｆｏｒｗａｒｄｉｎｔｏｔｈｅｓｔｏｍａｃｈｔｏｉｍｐｉｎｇｅｔｈｅｆｏｏｄｏｎｔｈｅｇａｓｔｒｉｃｓｈｉｅｌｄ (ＺｈａｎｇａｎｄＴａｉ,1 961 ) .Ｉｔｗａｓｒｅｐｏｒｔｅｄｔｈａｔｔｈｅｇａｓｔｒｉｃ… 相似文献
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STUDY ON EMBRYONIC DEVELOPMENT AND EARLY GROWTH OF TRIPLOID AND GYNOGENETIC DIPLOID LEFI—EYED FLOUNDER, PARALICHTHYS OLIVACEUS （T. et S. ） 总被引：1，自引：0，他引：1
The early effects of chromosomal manipulation of eggs and sperm on the yields of trip-loid and gynogenefic diploid larvae of Paralichthys olivaceus were investigated. Triploidy was achieved by cold shocking fen.ilized eggs at 0 - 2℃ for 45 minutes duration 5 minutes after fen.ilization, and the in-duced triploidy rates were 31.2% - 50% and the relative hatching rates were 53.3% - 99%. Gynnge-aetic diploids were obtained when eggs were inseminated with irradiated sperm and cold shocked at 0 -2℃ for 45 minutes duration 5 minutes after fertihzation. The induced gynogenetic diploid rates and the relative hatching rates were 94 % - 96 % and 48.5 % - 68.5 % respectively. The embryonic development of the triploid experimental group and of the gynogenetic diploid experimental group was delayed at first compared with the control group. But from the gastrula stage, it was not delayed anymore. There were no significant differences in the growth of the triploid experimental group larvae and the control group larvae, and in the growth of the gynogenetic diploid experimental group larvae and the control group larvae ac-cording to Student‘s t-test (α = 0.05). The relationship between the early growth of the triploid experi-mental group larvae and that of gynogenetic diploid experimental group larvae was also studied. 相似文献
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The gastric shield and underlying stomach epithelium of Chlymas ffarreri were examined at the light and ultrastructural levels.The results showed that the gastric shield consisted of two different size lobes joined together by a narrow middle piece,the thicker lobe was shaped like a funnel,but unclosed at the lateral side;the other lobe was irregularly triangular-shaped.The transverse section of the thicker lobe was obviously laminated and gradually decreased in thickness from the peak to the margins of the shield.The underlying epithelium bore numerous about 3μm diameter spherical processes formed by the apical plasmalemma of the epithelial cells becoming blunt pseudopodia.Microvilli and some interspersed cilia were present in the areas among the spherical processes regions where only microvilli existed.Rough endoplasmic reticulum,Golgi apparatus,different-sized electron-dense secretory granules and electron-lucent vacuoles as well las abundant mitochondria were present in the underlying epithelial cells.Fused droplets of the secretion from the underlying epithelial cells formed the gastric shield. 相似文献
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为揭示陕西石泉井不同频带水位对气压和固体潮的响应特征，采用频谱分析、相干函数和时移分析方法，对石泉井2015-11-01~2016-02-29的井水位、气压和理论重力固体潮等进行深入分析。结果表明，低频带（f＜0.5 cpd）井水位对气压响应较为一般且波动较大，对固体潮响应很差；中频带（0.5~8 cpd）井水位对固体潮响应很好，同时，对气压成分中的K1、S2和S3频点有较好的响应；高频带（f＞8 cpd）井水位与气压和固体潮的相干性均较差，这可能由于该频带井水位的信噪比较低和气压能量较弱等因素所致。此外，在全频带内，随着气压周期的增大，井水位的滞后时间也相应从1 min增至720 min；在中低频带的某些频点或频段，井水位对气压响应的时移存在超前和异常波动现象。
关键词： 相似文献
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A bloom of the dinoflagellate Scrippsiella trochoidea was detected for the first time in inner Tolo Harbor, Hong Kong in 2 000. Water samples were collected at eight stations
along a transect passing through a red tide patch for microscopic analysis of phytoplankton composition and high-performance
liquid chromatography (HPLC) analysis of phytoplankton pigments. During the bloom, the density of dinoflagellates was 1.1×106 cells L−1 within the patch and 8.6×105 cells L−1 outside the patch where the phytoplankton community was dominated by diatoms. After the bloom the S. trochoidea began to decrease in density and was replaced by diatoms as the dominating bloom-causing organisms at all stations, and the
density of dinoflagellates at most stations was less than 1.0 × 106 cells L−1. The status of S. trochoidea as the causative species of the bloom was indicated by the presence of peridinin, the marker pigment for dinoflagellates.
The shift from dinoflagellates to diatoms was marked by the decline of peridinin and the prevalence of fucoxanthin. Phytoplankton
pigment markers also revealed the presence of other minor phytoplankton assemblages such as cryptomonads and blue-green algal. 相似文献