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Dynamics of Land Use and the Evolution of Agroforestry Practices in the Dja Biosphere Reserve (DBR) Southeast Cameroon 被引量:1
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作者 Njini Loveline Munjeb Avana Tientcheu Marie Louise +2 位作者 Julius Tata Nfor Yerima Bernard Palmer Kfuban Jean-Michel Harmand 《Journal of Geoscience and Environment Protection》 2020年第5期346-358,共13页
The study had as objective to investigate the land use/land cover change from 1980 to 2019 in the Dja Biosphere Reserve using GIS and remote sensing techniques and the evolution of agroforestry practices. Semi structu... The study had as objective to investigate the land use/land cover change from 1980 to 2019 in the Dja Biosphere Reserve using GIS and remote sensing techniques and the evolution of agroforestry practices. Semi structured questionnaires were administered to 320 farmers who were randomly selected from 35 villages of the Dja Biosphere Reserve characterized by the presence of agroforestry systems. The land use map revealed six classes which were dense humid forest, perennial crop-based agroforestry practices, river, wetland, built up and bare areas. Between 1980 and 2008, dense humid forest lost -4.9% of its area to the benefits of perennial crop-based agroforestry practices, built up and bare land. Between 2008 and 2019, dense humid forest gain 1.77% of its area due to increase in perennial crop-based agroforestry practices and a subsequent increase in vegetation cover. Perennial crop-based agroforestry practices and built up increase progressively from 1980 to 2019. Farmers perceived hunting (36.3%), slash and burn agriculture (43.3%) and harvesting of tree-based products (20.3%) as the anthropogenic activities impacting the reserve negatively. The evolution of agroforestry practices were observed on the field, but the precise area under agroforestry practices in the study area need to be estimated. As a mitigation strategy to livelihood needs as well as the rehabilitation of degraded land, the conversion of pure cultivated agricultural land into agroforestry is a major opportunity. 展开更多
关键词 LAND Use/Land Cover GIS and Remote Sensing Techniques AGROFORESTRY dja BIOSPHERE RESERVE
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广西新黄鸡腔上囊和胸腺的发育及其T淋巴细胞的分布
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作者 李玉谷 叶镇邦 《基因组学与应用生物学》 CAS CSCD 1990年第2期53-60,共8页
10日龄鸡胚腔上囊开始形成囊腔和皱褶,并偶尔见到T淋巴样细胞;12日龄鸡胚出现淋巴滤泡;17日龄鸡胚滤泡髓质基本形成;3日龄雏鸡滤泡皮质出现。18日龄鸡胚开始形成DIA,随日龄的增长,DIA由腔上囊背侧近导管开口处逐渐扩展到导管背侧;7周龄... 10日龄鸡胚腔上囊开始形成囊腔和皱褶,并偶尔见到T淋巴样细胞;12日龄鸡胚出现淋巴滤泡;17日龄鸡胚滤泡髓质基本形成;3日龄雏鸡滤泡皮质出现。18日龄鸡胚开始形成DIA,随日龄的增长,DIA由腔上囊背侧近导管开口处逐渐扩展到导管背侧;7周龄前后到达与泄殖腔相连处。随着滤泡及DIA的形成,T淋巴样细胞分别出现于其中。滤泡中T淋巴样细胞的百分率,胚胎期大于孵出后。出生后T淋巴样细胞主要聚集于DIA内。9~11周龄腔上囊生长达到最大值,21.5~52周龄腔上囊消失。 14日龄鸡胚胸腺开始出现髓质,并可在其中检出ANAE细小颗粒型细胞,其百分率出生后大于胚胎期。 展开更多
关键词 腔上囊 胸腺 DIA T淋巴细胞 ANAE
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《出口商品包装(纸箱纸盒)》 2003年第2期138-150,共13页
关键词 国外公司 包装行业 包装机械 产品介绍 德国米伦松公司 传输带 法国dja公司 瓦楞工业刀具 淀粉糊胶配方技术 瑞典恩巴机械公司 柔版印刷粘箱开槽模切联动生产线
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