词汇简化是在不改变原句结构和语义的情况下,用更简单的词替换句子中的难词,提高文本面向特定群体读者的可读性。该文提出基于提示微调的汉语词汇简化方法PTCLS(Prompt-tuning Based Chinese Lexical Simplification)。PTCLS采用基于BAR...词汇简化是在不改变原句结构和语义的情况下,用更简单的词替换句子中的难词,提高文本面向特定群体读者的可读性。该文提出基于提示微调的汉语词汇简化方法PTCLS(Prompt-tuning Based Chinese Lexical Simplification)。PTCLS采用基于BART的底层架构,能够自然地生成不同字数的替代词,模型训练只需微调少量参数。在公开的汉语词汇简化数据集上的实验表明,该文提出的方法可以大幅超越目前最好的基线系统BERT-LS。深入分析揭示,微调方法只利用少量标注数据即可取得比全参数微调、手工提示和无监督方法更好的表现,尤其针对汉语同义词词典外的难词取得了更显著的性能提升。展开更多
黑碳仪是最常用的气溶胶吸光碳测试仪器,但其测得的吸光性能受到滤膜多重散射效应、颗粒物散射效应、颗粒物遮蔽效应的影响,只能算是 b ATN (光衰减系数),而不是 b in-situ (原位吸光系数).虽然已有学者提出几种将 b ATN 转换为 b cor ...黑碳仪是最常用的气溶胶吸光碳测试仪器,但其测得的吸光性能受到滤膜多重散射效应、颗粒物散射效应、颗粒物遮蔽效应的影响,只能算是 b ATN (光衰减系数),而不是 b in-situ (原位吸光系数).虽然已有学者提出几种将 b ATN 转换为 b cor (校正后吸光系数)的算法,但多是基于实验室模拟或高海拔地区气溶胶而开展的,与我国城市的气溶胶在理化性质方面有明显差别.为探索我国城市气溶胶将 b ATN 转换为 b cor 的问题,于2016—2017年冬季在北京市城区使用黑碳仪及光声消光仪分别测量 b ATN 和 b in-situ ,在分析多种算法的基础上,提出了面向城市气溶胶的校正方法.结果显示:在我国北方城市(以北京市为例),适应城市气溶胶的 f 值(遮蔽因子,为计算遮蔽校正系数的一个参数)为1.13, C (综合散射效应系数)为5.44;使用这些校正系数,将观测点由黑碳仪获取的 b ATN 转换为 b cor .与光声消光仪测定的 b in-situ 对比发现,无论是滤膜样点周期内还是长期观测时间内, b cor 与 b in-situ 均呈一致性,其中,长期观测时间内二者的相关性表达为 y =0.954 x +0.829(r 2为0.996),证明了校正方法的有效性和可信性.研究显示, b cor 与 b in-situ 整体相关性较高,并且获得了本地化的校正因子,实现了仅通过黑碳仪获取准确颗粒物吸光系数的目的.展开更多
目的:运用贝叶斯网状Meta分析的方法系统评价12种口服中成药联合多奈哌齐治疗痴呆的有效性及安全性。方法:在国家知识基础设施数据库(CNKI)、中国生物医学文献数据库(CBM)、中国学术期刊数据库(CSPD)及中文科技期刊数据库(CCD)、EMbase...目的:运用贝叶斯网状Meta分析的方法系统评价12种口服中成药联合多奈哌齐治疗痴呆的有效性及安全性。方法:在国家知识基础设施数据库(CNKI)、中国生物医学文献数据库(CBM)、中国学术期刊数据库(CSPD)及中文科技期刊数据库(CCD)、EMbase、Pubmed、Cochrane Library、Web of Science等主流数据库中进行了系统搜索,并查询ClinicalTrials.gov临床注册系统,检索起止时间为建库至2020年9月。所有纳入的随机对照试验均采用Cochrane系统评价手册进行质量评估。采用Stata 16.0、ADDIS1.16.8软件进行网状Meta分析。结果:最终纳入26个RCT,涉及12种口服中成药,网状Meta分析结果显示,在临床有效率方面,多奈哌齐联合复方海蛇胶囊排序最高;在改善认知功能方面,多奈哌齐联合灯盏生脉胶囊排序最高。结论:在多奈哌齐治疗基础上,加用中成药可提高临床治疗的有效性。建议今后进行中成药之间直接比较的高质量RCT,以提供更强有力的证据。展开更多
As one of the regions with intensive agriculture and rapid economic development in China,North China also has a high nitrogen(N)deposition.This study characterized the spatial pattern of N deposition in North China,co...As one of the regions with intensive agriculture and rapid economic development in China,North China also has a high nitrogen(N)deposition.This study characterized the spatial pattern of N deposition in North China,combining the tropospheric columns from satellite measurements and the simulated profiles from an atmospheric chemistry transport model.The total N deposition fluxes ranged from 16.3 to 106.5 kg N ha−1 yr−1,with an average of 54.5±17.2 kg N ha−1 yr−1.The high values were concentrated in urban and farmland areas,while low values were found in forests and grasslands with less human activities.Of the total N deposition,36%was deposited via precipitation,12%was deposited through dry particulate deposition,and the remaining 52%was comprised of dry gaseous deposition.For the seasonal variation of dry deposition,gaseous HNO3 and particulate NO3−were higher in winter and autumn,but lower in spring and summer.In contrast,gaseous NH3 and particulate NH4+were higher in spring and summer,but lower in winter and autumn.This is possibly caused by the seasonal differences in emission intensity between NOx and NH3 emission sources.The gaseous NO2 deposition did not show strong seasonal variation.The wet deposition was mainly affected by precipitation,with high values in summer and low values in winter.This research provides an objective spatial perspective and insight into the total N deposition in North China.展开更多
文摘词汇简化是在不改变原句结构和语义的情况下,用更简单的词替换句子中的难词,提高文本面向特定群体读者的可读性。该文提出基于提示微调的汉语词汇简化方法PTCLS(Prompt-tuning Based Chinese Lexical Simplification)。PTCLS采用基于BART的底层架构,能够自然地生成不同字数的替代词,模型训练只需微调少量参数。在公开的汉语词汇简化数据集上的实验表明,该文提出的方法可以大幅超越目前最好的基线系统BERT-LS。深入分析揭示,微调方法只利用少量标注数据即可取得比全参数微调、手工提示和无监督方法更好的表现,尤其针对汉语同义词词典外的难词取得了更显著的性能提升。
文摘黑碳仪是最常用的气溶胶吸光碳测试仪器,但其测得的吸光性能受到滤膜多重散射效应、颗粒物散射效应、颗粒物遮蔽效应的影响,只能算是 b ATN (光衰减系数),而不是 b in-situ (原位吸光系数).虽然已有学者提出几种将 b ATN 转换为 b cor (校正后吸光系数)的算法,但多是基于实验室模拟或高海拔地区气溶胶而开展的,与我国城市的气溶胶在理化性质方面有明显差别.为探索我国城市气溶胶将 b ATN 转换为 b cor 的问题,于2016—2017年冬季在北京市城区使用黑碳仪及光声消光仪分别测量 b ATN 和 b in-situ ,在分析多种算法的基础上,提出了面向城市气溶胶的校正方法.结果显示:在我国北方城市(以北京市为例),适应城市气溶胶的 f 值(遮蔽因子,为计算遮蔽校正系数的一个参数)为1.13, C (综合散射效应系数)为5.44;使用这些校正系数,将观测点由黑碳仪获取的 b ATN 转换为 b cor .与光声消光仪测定的 b in-situ 对比发现,无论是滤膜样点周期内还是长期观测时间内, b cor 与 b in-situ 均呈一致性,其中,长期观测时间内二者的相关性表达为 y =0.954 x +0.829(r 2为0.996),证明了校正方法的有效性和可信性.研究显示, b cor 与 b in-situ 整体相关性较高,并且获得了本地化的校正因子,实现了仅通过黑碳仪获取准确颗粒物吸光系数的目的.
文摘目的:运用贝叶斯网状Meta分析的方法系统评价12种口服中成药联合多奈哌齐治疗痴呆的有效性及安全性。方法:在国家知识基础设施数据库(CNKI)、中国生物医学文献数据库(CBM)、中国学术期刊数据库(CSPD)及中文科技期刊数据库(CCD)、EMbase、Pubmed、Cochrane Library、Web of Science等主流数据库中进行了系统搜索,并查询ClinicalTrials.gov临床注册系统,检索起止时间为建库至2020年9月。所有纳入的随机对照试验均采用Cochrane系统评价手册进行质量评估。采用Stata 16.0、ADDIS1.16.8软件进行网状Meta分析。结果:最终纳入26个RCT,涉及12种口服中成药,网状Meta分析结果显示,在临床有效率方面,多奈哌齐联合复方海蛇胶囊排序最高;在改善认知功能方面,多奈哌齐联合灯盏生脉胶囊排序最高。结论:在多奈哌齐治疗基础上,加用中成药可提高临床治疗的有效性。建议今后进行中成药之间直接比较的高质量RCT,以提供更强有力的证据。
基金This study was supported by the National Natural Science Foundation of China[grant numbers 41471343 and 41601457].
文摘As one of the regions with intensive agriculture and rapid economic development in China,North China also has a high nitrogen(N)deposition.This study characterized the spatial pattern of N deposition in North China,combining the tropospheric columns from satellite measurements and the simulated profiles from an atmospheric chemistry transport model.The total N deposition fluxes ranged from 16.3 to 106.5 kg N ha−1 yr−1,with an average of 54.5±17.2 kg N ha−1 yr−1.The high values were concentrated in urban and farmland areas,while low values were found in forests and grasslands with less human activities.Of the total N deposition,36%was deposited via precipitation,12%was deposited through dry particulate deposition,and the remaining 52%was comprised of dry gaseous deposition.For the seasonal variation of dry deposition,gaseous HNO3 and particulate NO3−were higher in winter and autumn,but lower in spring and summer.In contrast,gaseous NH3 and particulate NH4+were higher in spring and summer,but lower in winter and autumn.This is possibly caused by the seasonal differences in emission intensity between NOx and NH3 emission sources.The gaseous NO2 deposition did not show strong seasonal variation.The wet deposition was mainly affected by precipitation,with high values in summer and low values in winter.This research provides an objective spatial perspective and insight into the total N deposition in North China.
