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皱饰构造研究进展综述 总被引:1,自引:0,他引:1
在综述皱饰构造成因研究历程和国内外最新研究成果的基础上,总结评述了 4种有代表性的皱饰构造形成模式,其核心问题是在皱饰构造的形成过程中微生物席和物理作用的参与方式,以及受造席者、透光性、水动力条件、基底类型和生物扰动五大因素的影响程度.在对皱饰构造和现代微生物席对比研究的基础上,发现皱饰构造与微生物席的分布在很大程度上具有一致性,所以通过对现代微生物席的生长发育环境进行综合研究,推测了有利于皱饰构造发育的古环境.皱饰构造一般发育于潮间坪和滨外过渡带,并且在显生宙一般与生物扰动作用具有不相容性.皱饰构造是发育最普遍、受关注最广泛的保存在硅质碎屑岩中的微生物诱导形成的原生沉积构造,所以理清皱饰构造的成因模式及古地理分布,有利于碎屑岩微生物席学的发展,可以为理解硅质碎屑岩中的特殊沉积构造提供重要线索. 相似文献
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肯尼亚有一个名叫梅南加伊的火山口,坑里树木郁郁葱葱,景色宁静怡人。这样绝美的自然奇观却被当地人认为是邪恶的精灵附在了它的上面,因为最近几年,坑里频频发生一些令人费解的事,被当地人越传越离奇,越传越神秘。火山口名为"死尸之地"当地人都知道这坑里面经常发生一些稀奇古怪的事,但在附近居住的一些男孩仍愿意冒着被"鬼怪"围住的风险而去探访游玩,有些人真的一去不复返。于是,传言四起,当 相似文献
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Bacterial wilt (BW) caused by Ralstonia solanacearum is one of the most damaging diseases of potato (Solarium tuberosum L.) in Kenya and worldwide. In Kenya, potato tuber yield losses due to BW infection are estimated at 50 ~ 100%. Low soil fertility is also one of the most important constraints limiting potato production in central Kenya highlands. Farmers tackle this problem through use of inorganic fertilisers and organic manures, both of which amend the soil environment to influence bacterial wilt development. Undecomposed organic manures can also introduce the pathogen into a clean field. Between short rains 1999 and 2000, 10 on-farm extension-researcher-farmer-designed and farmer-managed trials were done at Kianjuki catchment in Embu District. The objective was to use farmers‘ participatory research approach and select the most suitable organic and inorganic fertiliser combination(s) with lowest BWI and acceptable usable tuber yields, and also to demonstrate use of some components of integrated disease management methods in reduction of disease incidence and spread. Seven treatments were proposed, presented to the farmers for discussion and the most relevant four were selected for evaluation. A newly released potato variety ‘Asante‘ was planted during the short rains 1999 and long rains 2000. BWI didn‘t result in significant differences between treatments but the tuber yields were significantly different in short rains of 1999 and 2000. During short rains 2000, both BWI and tuber yields and unusable tubers differed significantly between treatments. The results confirmed that well-decomposed manures or manures from pathogen-free areas can be used in combination with inorganic fertilisers to improve soil fertility and potato tuber yields in smallholder farms without influencing BWI. Use of certified seed tubers in pathogen free field and following recommended field sanitation measures resulted in apparently bacterial wilt free crop. Considering the high cost of inorganic ferfiliser and its negative effects on the environment, reduced usage at half the recommended rates combined with half rates of FYM is feasible option friendly to the farmer, soil and environment. The interviewed farmers also ranked the option as the most appropriate combination for soil fertility improvement for potato production in smallholder farms. 相似文献
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汽车驶出肯尼亚首都内罗毕,往西南方走了一个多小时,我问导游:我们进入东非大裂谷了吗?当地导游答:早进入了.我便觉得奇怪--怎么就没一点"掉进裂谷"的感觉呢?不一会,自己也觉得好笑,东非大裂谷平均宽度将近50公里,最宽处有200公里以上,汽车在里面行走,连一只小甲虫的分量都算不上,这道理也如同地球是圆的,而我们每天都感觉在走平路一样. 相似文献
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大多数人认识他,并不是因为他是中国最大的蛋糕连锁店好利来公司的掌门人,而是在喧嚣嘈杂、熙来攘往、焦躁无奈的北京地铁里,在等下一班地铁的间隙,在墙上一堆广告中发现一些特别的摄影作品,非洲肯尼亚纳库鲁湖的火烈鸟、马赛马拉的角马、乞力马扎罗的太象、纳米比亚埃托沙的长颈鹿、斑马还商美洲豹、犀牛、羚羊、鹅鹊、企鹅……在这些充满视觉震撼的作品旁边有一行并不显眼的小字,写着作者的名字:罗红。 相似文献
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考古学家通过研究一批非洲肯尼亚发现的“千禧祖先”和“肯尼亚平脸人”的骸骨,指出“千禧祖先”属于600万年前的人科动物。更为奇特的是,他们与300万年前的“露茜”相比更像现代人!他们从何处来,又到何处去了?是不是3O0万年的进化历程出问题了?目前,只有人类、黑猩猩、大猩猩、普通猩猩以及长臂猿等灵长类属于人科动物。“适生存、物竞天择”的规律还没有变,人科动物还能进化出新物种吗?人类还会向前进化吗? 相似文献
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丁一汇 《气象科技合作动态》2005,(6):11-12
2005年4月28~29日在日内瓦召丌丁WMO WCC3特别考查委员会会议。该委员会由米自美国、英国、中国、日本、巴西、俄罗斯、肯尼亚、马来西卫正、毛里求斯、伯里兹(中美洲)和欧盟的13位委员组成。会议开始时WMO副秘粥长和WCP代理司长分别说明了此次会议的背景、目的与要求。通过两天的讨论.最后形成了会议总结性件。 相似文献