9 research outputs found

    Study on the diversity and distribution of the pico-Chlorophyta and the pico-Haptophyta in the East China Sea

    Get PDF
    微微型绿藻和定鞭金藻是海洋生态系统中重要的初级生产者,在物质循环和能量流动过程中起重要作用,但目前对于微微型绿藻和定鞭金藻的多样性及分布的研究较少。本研究以东海为主要研究海区,以分子生物学的手段,包括18SrRNA克隆文库和荧光原位杂交结合酪酰胺信号放大(fluorescenceinsituhybridizationassociatedwithtyramidesignalamplification,FISH-TSA)技术来研究东海微微型绿藻和定鞭金藻的多样性及微微型真核浮游植物主要类群的时空分布特征,主要结果如下: (1)构建了基于东海及西太平洋黑潮区的6个代表性站位共8个样品的微微型绿藻和...The Chlorophyta and the Haptophyta are the important primary producers of marine ecosystem, play an important role in the material circulation and energy flow. But the knowledge of their diversity and distribution is very limited. In this study, we used molecular approaches, 18S rRNA clone library and fluorescent in situ hybridization associated with tyramide signal amplification (FISH-TSA) to inv...学位:理学硕士院系专业:环境与生态学院_环境科学学号:2262011115142

    文字探勘ESG新聞情緒分析對股票報酬率之研究-以臺灣大型股為例

    No full text
    近年來由於經濟迅速發展造成環境破壞,全球永續意識抬頭,大眾、企業與政府逐漸重視企業社會責任 (CSR),進而產生許多評估企業CSR表現的方式,但大多以永續報告書作為評估標準,每年發佈對於短期投資人來說並不效率,故本研究以ESG媒體情緒作為一種衡量企業CSR表現的指標,透過文字探勘、情感分析為投資人提供衡量企業CSR表現的分析模式,搜集主觀(PTT平台)與客觀(中央通訊社)媒體新聞進行文本分類與情緒分析,了解媒體對企業CSR表現的評價與形象。 本研究透過企業永續報告書建構ESG環境、社會、公司治理分類詞表作新聞文本分類,文本情感分析使用雙向長短記憶神經網路(Bi-LSTM)模型,並將新聞文本根據情緒傾向分為「正面」、「負面」,且將樣本資料分割為前疫情時期與後疫情時期,最後使用Fama-Macbeth(1973)迴歸模型分析,深入探討ESG媒體情緒與報酬率之關聯與後疫情時代ESG媒體情緒之影響力。 經本研究搜集資料對其進行分析之實證結果的研究結論主要如下:(1)ESG媒體情緒傾向於正向短期股價報酬率。(2)不同資料來源情緒傾向不同,對投資人的影響也不同。(3) ESG媒體情緒有分類衡量的必要。 (4)媒體情緒對個股報酬率有短期正向效果,延遲反向效果,且分類為正負面後,正面新聞有短期正向效果,負面新聞則有延遲反向效果。 (5)ESG負面新聞對股價報酬率有延遲反向效果,正面新聞不影響。(6)後疫情時代新聞情緒對個股報酬率影響程度提高,但ESG新聞則無

    Characterization of photosynthetic properties of two marine picophytoplankton using the rapid light curve

    No full text
    超微型浮游植物是海洋中重要的初级生产者,浮游植物吸收的光一部分用于光合作用,另一部分以荧光或热的形式耗散.本文利用调制叶绿素荧光仪(PulSE-AMPlITudE-MOdulATIOn,PAM)测定2株海洋超微型真核藻:细小微胞藻(MICrOMOnAS PuSIllA)和梨形脂金藻(PInguIOCHrySIS PyrIfOrMIS)在不同光强下的叶绿素荧光和快速光曲线.结果表明细小微胞藻和梨形脂金藻在不同光强下的光系统II(PS II)的最大光量子产量(fV/fM)分别为0.572~0.634和0.624~0.426;最大相对电子传递速率(rETrMAX)分别为61.58~163.56和76.69~143.17μMOl/M2·S-1;半饱和光强(Ik)分别为212.37~946.00和307.44~671.28μMOl·M-2·S-1;光能利用效率(α)分别为0.29~0.17和0.25~0.21.细小微胞藻和梨形脂金藻分别属于高光型和低光型的超微型浮游植物,光照条件会显著影响超微型浮游植物的光合特性,但不同类型的超微型浮游植物的光合特性对光的响应存在差异.Picophytoplankton were the most important primary producers in marine ecosystem.The light energy absorbed by phytoplankton were separated into two parts,one was used in photosynthesis process,the other was dissi-pated through chlorophyll fluorescence or thermal energy.In this study,we used pulse-amplitude-modulation( PAM) fluorometry to investigate the chlorophyll fluorescence and the rapid light curve of two marine picophytoplankton: Micromonas pusilla and Pinguiochrysis pyriformis under different light conditions.The results showed the maximum quantum yield of PSII( Fv/Fm) for M.pusilla under different light conditions ranged from 0.572 to0.634,while the P.pyriformis obtained the values from 0.624 to 0.426.The maximum relative electron transport rate( rETRmax),the minimum saturating irradiance( Ik) and the light energy utilization efficiency( α) for M.pusilla and P.pyriformis were 61.58 ~ 163.56 and 76.69 ~ 143.17 μmol /m2·s- 1,212.37 ~946.00 and 307.44 ~671.28 μmol /m2·s- 1,0.29 ~0.17 and 0.25 ~0.21,respectively.M.pusilla was characterized as a high-light type picophytoplankton and P.pyriformis was recognized as a low-light type picophytoplankton.The light condition would significantly influence the photosynthetic properties of picophytoplankton,but the responses were different in M.pusilla and P.pyriformis.国家自然科学基金资助项目(41176112); 国家海洋局海洋公益资助项目(201005015-5;201105021-03); 国家海洋专项资助项目(GASI-03-01-02-03

    Contribution of NSFC in promoting the interdisciplinary subject of Xiamen University:a Summary of engineering and material subject

    No full text
    国家自然科学基金(以下简称科学基金)作为我国支持基础研究的主渠道之一,面向全国,重点资助具有良好研究条件、研究实力的高等院校和科研机构中的研究人员[1]。科学基金自成立以来秉承"支持基础研究、坚持自由探索、发挥导向作用"的战略定位,实施源头创新战略、科技人才战略、创新环

    Fluvial Bed Variation of Dongmen Creek After Cutting Down the Check Dam

    No full text
    為穩定台灣恆春東門溪下游滯洪池庫容,本研究針對上游兩座可調式防砂壩提供操作建議。為達此目的乃採用室內渠槽試驗探討各種調降防砂壩方式,對東門溪上下游河床變化及土砂運移量之影響。試驗結果顯示,隨著二號壩溢口橫桿調降,其上游高程呈現等速下降、遷急點呈現等速上移趨勢,而下游會受到一號壩的影響產生回淤情形,其高程及遷急點變化無固定趨勢。在調降壩體初期時有較大的土砂運移量,使得壩體上下游河床坡度變化亦較大,而隨著二號壩溢口調降一半橫桿,土砂運移量及上下游河床坡度已趨近不變,達到上下游河床之平整化。逐次調降可使遷急點緩慢變化並避免土砂量一次性下移所造成之危害。To stabilize the capacity of the downstream detention pond, the recommendations of upstream two adjusted check dams in Dongmen Creek, Hengchun, Taiwan are provided. Moreover, to investigate the effects of various types of check dams on sediment transport and fluvial bed variations, the flume experiments were used. The results show that as the horizontal bars in the second dam are gradually removed, the elevation decreases and the knick points move upstream at a constant velocity. However, the first dam causes sediment deposit that flushed from second dam, and the changes in elevation and knick points do not significantly affect the trend between two dams. In addition, large amounts of sediment transport causes substantial slope change during the initial stages of adjusting a check dam. The sediment transport and slope stabilize when half the number of horizontal bars are removed from the second dam. Therefore, gradually cutting down the check dam can slow the change in knick points and prevent the disaster caused by large amounts of sediment being suddenly deposited in the river

    Literaturverzeichnis und Anhang

    No full text
    corecore