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阿克苏地区中龄期苹果树的根系空间分布研究 被引量:4
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作者 李宏 董华 +1 位作者 杨婵 郭光华 《西部林业科学》 CAS 北大核心 2012年第6期9-14,共6页
采用剖面挖掘和分层取样法,利用WinRHIZO Pro2010a根系分析系统对新疆阿克苏地区苹果园漫灌条件下的中龄期(基径9 cm)红富士苹果树的吸收根(根径<2 mm)和输导根(根径≥2 mm)的空间分布状况进行了研究。结果表明,在水平方向的土壤中,... 采用剖面挖掘和分层取样法,利用WinRHIZO Pro2010a根系分析系统对新疆阿克苏地区苹果园漫灌条件下的中龄期(基径9 cm)红富士苹果树的吸收根(根径<2 mm)和输导根(根径≥2 mm)的空间分布状况进行了研究。结果表明,在水平方向的土壤中,苹果树吸收根与输导根根长密度与根表面积表现出"单峰型"的分布规律,吸收根根长密度和根表面积最大值出现在离树干水平距25~50 cm处的土壤内,输导根根长密度和根表面积最大值出现在离树干水平距0~25 cm处的土壤内,80%以上的根系分布在离树干水平距0~125 cm的土壤内。在垂直方向即土层中,苹果树的吸收根根长密度表现出"双峰型"的分布规律,吸收根根表面积与输导根的根长密度和根表面积都表现出"单峰型"的分布规律,80%以上的吸收根与输导根分布在0~80 cm的土层内。总之,距树干0~125 cm的土壤内及0~80 cm的土层是中龄期苹果树的重要分布区域,可作为拟定阿克苏地区苹果园中龄期苹果树田间水分、养分管理措施的理论依据。 展开更多
关键词 阿克苏地区 中龄期 苹果树 根系 空间分布
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直干桉人工林幼中龄不同间伐量及施肥的对比试验 被引量:3
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作者 石忠强 蒋云东 +5 位作者 余文辉 张国华 李涛 赵加永 廖春梅 陈艳琼 《西部林业科学》 CAS 2004年第4期41-44,共4页
对 6~10年生幼中龄期直干桉人工林不同间伐量及施肥效应的对比试验结果表明, 不同间伐量及施肥对直干桉林木的生长和地上部分的生物量均存在显著的影响。此龄期的直干桉人工林以间伐后林木保留株数为 61株·m-2的林分为最佳。通过... 对 6~10年生幼中龄期直干桉人工林不同间伐量及施肥效应的对比试验结果表明, 不同间伐量及施肥对直干桉林木的生长和地上部分的生物量均存在显著的影响。此龄期的直干桉人工林以间伐后林木保留株数为 61株·m-2的林分为最佳。通过分析主伐保留株数对直干桉林分生长量、生物量的影响, 得知如果以径阶 18 22cm为培育目标, 此直干桉人工林最适宜的保留株数为 617 ~697株·hm-2。此外, 中龄期施肥有利于提高直干桉人工林的生长量、生物量和蓄积量, 故在生产中除幼龄期必须施肥外, 中龄期也应该适当施肥。 展开更多
关键词 直干桉人工林 中龄期 间伐 施肥
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Gemcitabine in elderly patients with advanced pancreatic cancer
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作者 Olivia Hentic Vinciane Rebours +5 位作者 Philippe Lévy Philippe Ruszniewski Pascal Hammel Magaly Zappa Chantal Dreyer Eric Raymond 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第30期3497-3502,共6页
AIM: TO assess feasibility, tolerability and efficacy of gemcitabine-based chemotherapy in patients ≥ 75 years old with advanced pancreatic cancer. METHODS: All consecutive patients ≥ 75 years old with advanced pa... AIM: TO assess feasibility, tolerability and efficacy of gemcitabine-based chemotherapy in patients ≥ 75 years old with advanced pancreatic cancer. METHODS: All consecutive patients ≥ 75 years old with advanced pancreatic adenocarcinoma were included in this retrospective study. Necessary criteria to receive chemotherapy were: performance status 0-2, adequate biological parameters and no serious comorbidities. Other patients received best supportive care (BSC). RESULTS: Thirty-eight patients (53% women, median age 78 years, range 75-84) with pancreatic cancer (metastatic: n = 20, locally advanced: n = 18) were studied. Among them, 30 (79%) were able to receive chemotherapy [median number: 9 infusions (1-45)]. Six patients (23%) had at least one episode of grade 3 neutropenia and one patient developed a grade 3 hemolytic-uremic syndrome. No toxic death occurred. Three patients (11%) had a partial tumor response, 13 (46%) had a stable disease and 12 (43%) had a tumor progression. Median survival was 9.1 mo (metastatic: 6.9 too, locally advanced: 11.4 too). CONCLUSION: Tolerance and efficacy of gemcitabinebased chemotherapy is acceptable in elderly patients in good condition, with similar results to younger patients. 展开更多
关键词 ELDERLY PANCREAS CANCER GEMCITABINE
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SHRIMP zircon U-Pb dating of late Paleoproterozoic kondalites in the Daqing Mountains area on the North China Craton 被引量:47
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作者 DONG ChunYan WAN YuSheng +4 位作者 XU ZhongYuan LIU DunYi YANG ZhenSheng MA MingZhu XIE HangQiang 《Science China Earth Sciences》 SCIE EI CAS 2013年第1期115-125,共11页
The Daqing Mountains area comprises a typical occurrence of the Khondalite Belt in the Western Block of the North China Craton (NCC). In this area, both early and late Paleoproterozoic metasedimentary rocks have been ... The Daqing Mountains area comprises a typical occurrence of the Khondalite Belt in the Western Block of the North China Craton (NCC). In this area, both early and late Paleoproterozoic metasedimentary rocks have been identified in what was originally called the Upper Wula Mountains "Subgroup". Six metasedimentary rock samples yielded SHRIMP U-Pb zircon ages of 2.56-2.04 Ga for detrital and 1.96-1.83 Ga for metamorphic zircons. Based on these data and previously published results, the following conclusions can be drawn: 1) The source region for the late Paleoproterozoic detrital sedimentary rocks is mainly 2.55 2.4 and 2.2 2.04 Ga in age, consistent with the early Precambrian geological history identified widely in the basement of the NCC. 2) The majority of sedimentary rocks of the khondalite series were deposited between 2.04 and 1.95 Ga, and then in a protracted period (1.96 and 1.83 Ga) underwent a complex history of amphibolite to granulite-facies metamorphism. 展开更多
关键词 KHONDALITE PALEOPROTEROZOIC ZIRCON SHRIMP U-Pb dating Daqing Mountains North China Craton
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New SIMS U–Pb zircon age and its constraint on the beginning of the Nantuo glaciation 被引量:13
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作者 刘鹏举 李献华 +4 位作者 陈寿铭 兰中伍 杨犇 尚晓东 尹崇玉 《Science Bulletin》 SCIE EI CAS CSCD 2015年第10期958-963,I0008,共7页
A new SIMS U-Pb zircon age of 654.2 ± 2.7 Ma was reported from the middle Datangpo Formation in Changyang County of Hubei Province, China. The age is identical with that of 654 ± 3.8 Ma from the top Datangpo... A new SIMS U-Pb zircon age of 654.2 ± 2.7 Ma was reported from the middle Datangpo Formation in Changyang County of Hubei Province, China. The age is identical with that of 654 ± 3.8 Ma from the top Datangpo Formation in western Hunan Province, revealing that the volcanic activities (- 654 Ma) may have occurred widely in South China. The occurrence of the tuff beds (-654 Ma) at different intervals of the Datangpo Formation indicates that the erosion process after the Datangpo deposition varied significantly in different areas. It is thus consequently suggested that the rift in South China was active until the Nantuo glaciation. In addition, the new age confirms that the Nantuo glaciation started much later than 654 Ma. 展开更多
关键词 South China Neoproterozoic - Datangpo Formation SIMS U-Pb zircon dating Nantuo glaciation
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