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同源四倍体水稻:低育性机理、改良与育种展望 被引量:4
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作者 刘向东 吴锦文 +1 位作者 陆紫君 Muhammad Qasim Shahid 《遗传》 CAS CSCD 北大核心 2023年第9期781-792,共12页
同源四倍体水稻具有籽粒增大、营养成分增加和抗性增强等特点,但其育性普遍偏低,影响产量,无法直接应用。高育性四倍体水稻的成功创制解决了同源四倍体水稻育性偏低的瓶颈问题,然而该类型多倍体水稻能否在生产上推广应用需要进一步探讨... 同源四倍体水稻具有籽粒增大、营养成分增加和抗性增强等特点,但其育性普遍偏低,影响产量,无法直接应用。高育性四倍体水稻的成功创制解决了同源四倍体水稻育性偏低的瓶颈问题,然而该类型多倍体水稻能否在生产上推广应用需要进一步探讨。本文总结了同源四倍体水稻及其杂种F1育性偏低的细胞和分子遗传学机理研究的概况,重点介绍了高育性四倍体水稻的主要类型及最新的研究进展,最后提出未来利用新型四倍体水稻开展多代杂种优势等研究的设想,以期为水稻多倍体育种提供参考。 展开更多
关键词 水稻 同源四倍体水稻 新型四倍体水稻 PMeS多倍体水稻 杂种优势利用
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N叉树上的可达渗流
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作者 胡治水 吴金文 董梁 《中国科学技术大学学报》 CAS CSCD 北大核心 2022年第11期4-11,I0003,共9页
考虑一棵有根的N叉树,赋予此树的每个顶点一个独立同分布的连续随机变量。如果从根点到某个顶点路径上的随机变量是递增的,我们就称这个顶点是可到达的。考虑在N叉树中前k层可到达顶点的数目C_(N,k)和可到达顶点的总数目C_(N),当N→∞时... 考虑一棵有根的N叉树,赋予此树的每个顶点一个独立同分布的连续随机变量。如果从根点到某个顶点路径上的随机变量是递增的,我们就称这个顶点是可到达的。考虑在N叉树中前k层可到达顶点的数目C_(N,k)和可到达顶点的总数目C_(N),当N→∞时,得到了C_(N,βN)不同的极限分布(随着β从0到+∞变化),建立了C_(N)的极限性质。当N固定时,也考虑了N叉树中前n层最长递增路径长度的大数定律。 展开更多
关键词 N叉树 可达渗流 可达顶点 最长递增路径
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肺部经皮穿刺活检术后气胸发生的风险因素及其风险应对方案分析
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作者 吴瑾文 王利昭 +1 位作者 周丹 任红 《中华介入放射学电子杂志》 2024年第2期150-154,共5页
目的分析肺部经皮穿刺活检(percutaneous transthoracic needle biopsy,PTNB)术后气胸发生的风险因素并探讨其风险应对方案。方法回顾性分析2021年1月至2022年12月绵阳市中心医院收治的1246例PTNB患者的基本资料、病灶特征及穿刺程序等... 目的分析肺部经皮穿刺活检(percutaneous transthoracic needle biopsy,PTNB)术后气胸发生的风险因素并探讨其风险应对方案。方法回顾性分析2021年1月至2022年12月绵阳市中心医院收治的1246例PTNB患者的基本资料、病灶特征及穿刺程序等。统计患者有无气胸的发生情况,采用单因素及Logistic回归分析筛选出PTNB术后气胸发生的危险因素,并据此制定出有效的风险干预方案。结果1246例PTNB患者中无气胸1108例(88.92%),并发气胸138例(11.08%);其中,少量气胸98例(7.87%),中等量气胸38例(3.05%),大量气胸2例(0.16%)。单因素分析显示,年龄、病灶长径、病灶位置、胸膜凹陷征、毛刺征、分叶征、病灶周围肺气肿、穿刺深度、穿刺时间、穿刺距胸膜距离均是肺部PTNB术后气胸发生的相关因素(P<0.05)。Logistic回归分析显示,年龄>65岁、病灶长径≤3 cm、病灶位于中下叶、病灶周围肺气肿、穿刺深度>4 cm、穿刺距胸膜距离>2 cm均是肺部PTNB术后气胸发生的独立危险因素(P<0.05)。结论年龄>65岁、病灶长径≤3 cm、病灶位于中下叶、病灶周围肺气肿、穿刺深度>4 cm、穿刺距胸膜距离>2 cm均是肺部PTNB术后气胸发生的独立危险因素,临床据此建立规范的PTNB流程及应对气胸的风险干预方案,对提升临床医疗安全意识、减少气胸发生,并确保PTNB的顺利进行至关重要。 展开更多
关键词 肺穿刺活检术 气胸 风险因素 风险干预方案
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Evaluation of the Biodiversity Conservation Function in Liaohe Delta Wetland,Northeastern China 被引量:4
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作者 Wenying YU Ruipeng JI +4 位作者 Xiuzhen HAN Long CHEN Rui FENG jinwen wu Yushu ZHANG 《Journal of Meteorological Research》 SCIE CSCD 2020年第4期798-805,共8页
The scientific evaluation of the wetland biodiversity conservation function is the basis of balanced wetland protection and development. Our research sought to provide references for the protection of wetland ecologic... The scientific evaluation of the wetland biodiversity conservation function is the basis of balanced wetland protection and development. Our research sought to provide references for the protection of wetland ecological environments as well as the related planning and management policies. The study established a fitting model for evaluating the biodiversity conservation function in the Liaohe Delta, northeastern China. The new model, the Wetland Biodiversity Conservation Indicator(WBCI), was with four input factors, including the vegetation coverage(VC), habitat suitability index(HI), land use and land cover(LULC) index(LI), and threat factor index(TI) of the LULC type. The values assigned to HI and TI were based on Integrated Valuation of Ecosystem Services and Tradeoffs(In VEST)habitat quality models. The weights of all the factors in WBCI were valued with the Principal Component Analysis(PCA). We evaluated the wetland biodiversity conservation function of Panjin, Liaohe Delta, China, by using the WBCI model based on Gaofen-1(GF-1) satellite data in 2018, and the result was verified with In VEST and other models. It showed that the output map was similar to that of In VEST, with the higher-quality habitat including the wetland, tidal flat, water body, and forest, as well as the lower-quality land use types including the paddy field, crop field, construction land, and land used by traffic. The wetland biodiversity conservation function was better in areas less affected by human disturbance, with very abundant species and good-quality habitat. It was poor in areas impacted by more frequent human activities such as the land cultivation, housing, and traffic, which led to the landscape fragmentation. The WBCI model provided a more accurate reflection of the bird distribution than the In VEST model. The WBCI model was able to reflect the difference in quality of each habitat grade, in contrast to the net primary productivity(NPP) method and species distribution models(SDMs). The new model was, therefore, simpler and suitable in reflecting the quality of wetland biodiversity function in the Liaohe Delta. 展开更多
关键词 WETLAND BIODIVERSITY conservation function habitat quality EVALUATION
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Dynamic Response of Phragmites australis and Suaeda salsa to Climate Change in the Liaohe Delta Wetland 被引量:3
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作者 Yushu ZHANG Wenying YU +4 位作者 Ruipeng JI Yijun ZHAO Rui FENG Qingyu JIA jinwen wu 《Journal of Meteorological Research》 SCIE CSCD 2021年第1期157-171,共15页
Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are ... Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are therefore of great importance. We used medium-and high-resolution satellite data, meteorological station data, and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta Wetland from 1998 to 2017, as well as their growth response to the climate change. The results showed that during 1998–2017, the areas of both P. australis and S. salsa wetlands alternated through periods of decreasing,increasing, and then decreasing trends. The annual change in the area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index(NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged, and decreased accounted for 81.8%, 12.3%, and 5.9%, respectively, of the total area;evaporation and wind speed were the main meteorological factors affecting the NDVI;and contribution rates of the climate change and human activities to the NDVI were 73.2% and 26.8%, respectively. The area with vegetation cover being mainly S.salsa that was improved, unchanged, and decreased accounted for 63.3%, 18.3%, and 18.4%, respectively, of the total area;and no meteorological factors significantly affected the NDVI of S. salsa in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover.The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity. 展开更多
关键词 Liaohe Delta WETLAND Phragmites australis Suaeda salsa climate change
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