青海史前农业的出现与土著人群生存方式的改变

距今约6000年左右,来自甘肃东部的仰韶文化人群逐步西迁到青海东部地区,带来了种植已久的粟和黍以及成熟的农业生产技术,农业技术传播到青海后很快被从事采集狩猎经济的青海土著人群所接受。到马家窑文化马家窑类型期,史前农业生产的空间范围迅速在河湟地区拓展开来,很快到达了适合史前农业生产的最大区域。东部河湟地区农业文明的优越性吸引了青海西部高海拔的地区的采集狩猎人群去从事农业生产,这一时期青海西部高海拔地区的细石器遗址收缩甚至于消失。

南朝宋齐时代的岭南统治与土著人群

南朝随着中央集权的加强,对岭南俚区的统治渐次展开。宋齐两代广州地区的郡县化加速进行,政区析置推向深山海隅,西、南二江督护的设置,强化了对西江流域及其以南区域俚人的征服,推动了越州高层政区的成立,土著人群不断纳入华夏统治成为编户齐民,进入帝国官僚体制的土豪酋帅逐渐形成华夏认同。交州地区在刘宋世改变了家族世袭统治的状态,中央的直接支配一定程度上恢复了帝国的政治权威,然而新置郡县的不明、编户化的停滞,均表明华夏统治的限度,萧齐世对土著势力逐步失控,离心倾向日益突出。

论清代都柳江流域木材贸易的兴起、影响与发展阶段

清代都柳江的疏浚是在王朝国家开辟“新疆”的背景下进行的,乾隆以后,木材贸易随着江河的疏通而渐起。便利的航运条件、土著人群与外来移民关系的改变、丰富的林木资源带动了木材的开采和运销。清代都柳江流域木材贸易经过三个阶段的发展,木材市场得以建构和走向成熟,林地林木流转促使了产权观念在地方社会的普及,土著人群转变了生计方式和产生了以木材为核心的商业观念,其日常经济生活亦得到改变。

An Ecological Survey of Limoniastrum guyonianum： A Halophyte Native Tree in Arid Zones of Algeria

In arid and semi-arid regions soil salinity is a constraint for the development of plants and a threat to balance food in these soils some species are threatened with extinction. Two natural constraints drought and salinity have altered the ecosystem stability, but it has always conditions more or less favorable to the existence of a spontaneous flora adapted to the climatic and edaphic stress. The aim of this study is to describe a halophyte native tree and its climatic and edaphic requirements, it is a case of Limoniastrum guyonianum. According to this survey L. guyonianum, grows well under high temperature, insolation and evaporation and low rainfall and humidity. The species tolerate the soil basic pH, salinity, calcareous and do not need the organic matter and chlorure ions There are some morphological adaptations in the L. guyonianium to the several conditions as the length of the root and cylindrical shapes of the leaves and their extraction of salt.