琥珀,哪里找?

正琥珀在世界上很多地方均有发现,但大都沉积规模很小而且很局限。大部分产地的琥珀质地都不够纯,也不能制作珠宝。能达到珠宝级,而且规模庞大沉积的琥珀几乎仅见于波罗的海地区和多米尼加共和国,这两处琥珀产地目前都在进行商业性挖掘。含有昆虫的琥珀主要产自波罗的海地区、多米尼加共和国、缅甸、墨西哥、黎巴嫩、西伯利亚、加拿大、美国新泽西州、西班     

西江千户苗寨,家园?公园?

<正>西江千户苗寨位于贵州省雷山县,由十余个依山而建的自然村寨相连成片,是全国最大的苗族聚居村寨,共1250户,5600多人。2008年,借贵州第三届旅游发展大会在西江召开之机,当地政府对村寨进行了全面整修,修建了铜鼓坪、观景台、步行街、风雨桥等景观设施,期望将西江打造为5A级景区,耗资人民币8000万元。     

TTF,TTH,TPF还是TTCH?

氯化三苯基四氮唑(TTC)无色晶体能溶于水,还原为三苯基甲?后呈红色,不溶于水且在空气中不会自动氧化,相当稳定,已被用作脱氢酶的受氢体广泛用于检测根系、花粉和种子的活力。TTC英文全称是2,3,5-triphenyl tetrazolium Chloride,其缩写除有人用Tz外,基本上已被通称为TTC。但对三苯基甲?则有的称TTH,有的称TTF,还有的用TTCH,颇不一致。那么究竟用什么符号为好呢?     

Diterpenes,taxonomic markers?

The chemosystematic potential of the 15 more common diterpene types in vascular plants was evaluated. Oxidation levels and skeletal specializations indicate diterpene biosynthesis to involve contrasting modes in pteridophytes and angiosperms on one hand, and in gymnosperms on the other. In angiosperm lineages diterpene diversification accompanies trends towards increase of herbaceousness and depletion of polyphenols, i.e., towards evolutionary advance. Nevertheless, even closely related families may display disjunctions of diterpene type and substitution. Thus the taxonomic value of this metabolic class remains confined to single (advanced) families.Part 36 in the series Plant chemosystematics and phylogeny. For Part 35 seeBorin & Gottlieb (1993). Based in part on the doctoral thesis presented byM. R. Figueiredo to Universidade de São Paulo in 1992.