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我国科学家发现古老细菌化石揭示地球与生命协同演化奥秘_我的网站

4公司声讨战狼2

一 | New Delhi, Oct 13 (UNI) Congress leader Shashi Tharoor on Thursday said there were systematic flaws in the Congress presidential election process, even as he clarified he was not suggesting it was intentional.

The Thiruvananthapuram MP also indicated at differential treatment between him and Mallikarjun Kharge, who is being seen as the choice or the party leadership. Congress has maintained the party is not backing any candidate officially.

Addressing a press conference here, Tharoor said while he is not pointing fingers at Central Election Authority Chairman Madhusudan Mistry, there are flaws in the system.

"I am not saying anything against Mr. Mistry, there are some flaws in the systems which we all know. There have not been elections for 22 years..." said Tharoor.

He said there were discrepancies in the lists of voters provided.

"One list was given earlier, another list was given on Wednesday.... Some names were different in the lists, for some names, there was no phone number," he said.

"I am not saying it's being done intentionally. There have not been elections in our party for a long time. So there are issues. I know Mr. Mistry and his team are trying to hold free and fair elections. We are not complaining against them but there ar problems with the system," he said.

"That is why I used open mediums to take my message across. I am not sure I will be able to reach everyone before 17th."

He also pointed at differential treatment to candidates.

"Another issue is what some leaders did, that is why I said there is no level playing field. At a lot of places, big leaders, PCC chiefs welcome Kharge ji, call people for meetings. This happened for only one candidate, not for me," he said.

"Many times when I went to some PCC, the PCC chief became busy on the day...I am not complaining, but do you not see a difference in treatment?"

Election will be held on October 17, counting will be held on October 19 and results will be declared.

UNI AO BAV。

二 | 人民网西安4月21日电（记者李志强）近日，记者从西北大学获悉，该校早期生命与环境研究团队与中国科学院地质与地球物理研究所、上海交通大学等单位科学家合作，在5.18亿年前的寒武纪清江生物群中发现多细胞结构的丝状硫酸盐还原细菌化石清江丝菌，并结合分子生物学分析结果，还原了硫酸盐还原菌与地球环境协同演化历史。　　细菌化石是指保存在岩石中的细菌遗体或其活动留下的痕迹。据专家介绍，在此之前，除了少数有特殊形貌的蓝细菌化石和趋磁细菌磁小体化石外，在古老地质记录中还没有发现可靠的硫酸盐还原细菌化石。硫酸盐还原菌的演化与地球环境变化的关系，科学界也没有明确的认识。　　清江丝菌化石的产地和环境背景。(a)早寒武纪扬子台地岩相古地理图和清江丝菌及所属清江生物群的化石产地；（b）清江生物群生态复原图西北大学供图　　团队成员、西北大学教授张兴亮介绍，硫酸盐还原细菌是一类在厌氧条件下生活的微生物，它们利用硫酸盐氧化有机碳来获取能量，并在此过程中将硫酸盐还原产生代谢产物硫化氢。这些细菌在环境科学、生态学和工业领域中都具有极为重要的意义。它们是地球硫循环的关键推动者，通过还原硫酸盐参与到硫的生物地球化学循环中，影响硫在不同价态和形态间的转化。同时，它们也参与有机质的分解和甲烷氧化等过程，从而调节海洋的氧化还原状态和温室气体排放。　　研究团队根据化石证据和谱系基因组学分析结果，提出硫酸盐还原菌与地球氧化事件协同演化假说，认为脱硫细菌门首先在24亿年前的大氧化事件期间发生辐射演化，约8.5亿年前演化出丝状多细胞种类；在新元古代末期，地球第二次氧化事件导致海底广泛氧化，丝状种类约在5.6亿年前获得传导电子功能，硫酸盐还原通路逆转，演化成可以跨越氧化还原界面，一端在还原带氧化硫，另一端在氧化带还原氧的电缆细菌。清江丝菌化石的多细胞丝状体形态。

三 | 西北大学供图　　据介绍，这项研究是古生物学、地球化学、谱系基因组学交叉合作的结果，同时借助了多种高分辨率、高精度显微和微区原位分析技术，是在多学科交叉背景下探究微生物硫酸盐还原作用与地球环境协同演化的首次尝试，对融合利用显微学和基因组学等最新技术、促进地学与生物学前沿交叉、探索解决地球与生命协同演化等具有重要意义。　　同时，这项研究还能够为科学家探讨“生命在火星等其他行星上的存在、演化的可能性研究”提供参考，为人类寻找地外生命提供了一种可能的途径。