This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained ...This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients.展开更多
Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpirat...Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpiration rate and lowest LWP yielded the lowest, while TMS 91/02324 and TMS 91/02327 with intermediate rate and highest LWP yielded the highest, indicating that high transpiration rate associated with low LWP reduced yield. Transpiration was lower in the fringe with deeper water table than valley bottom at deep water table site, while at shallow water table, it was higher in the fringe than valley bottom, suggesting that drought and excess moisture reduced transpiration. LWP and water table depth correlated negatively indicating that shallow water table reduced transpiration by reducing LWP. Transpiration increased and LWP decreased as radiation, leaf temperature and vapour pressure deficit increased and differences in these microclimatic conditions caused differences in the two processes between sites, years and time of day. Under mild water stress, transpiration and LWP were higher in the afternoon than the morning, but the reverse occurred under severe stress. TMS 91/02324 and TMS 91/02327 had the highest LWP under severe stress, indicating their higher drought tolerance than the other cultivars.展开更多
电网现场作业风险等级影响着作业的安全性和经济性,目前风险等级评级主要依赖于人工评级,存在一定的错误率。以国网公司的作业风险分级表与实际现场历史文本库作为研究对象,在充分分析各自文本特点的基础上,提出了基于BERT(bidirectiona...电网现场作业风险等级影响着作业的安全性和经济性,目前风险等级评级主要依赖于人工评级,存在一定的错误率。以国网公司的作业风险分级表与实际现场历史文本库作为研究对象,在充分分析各自文本特点的基础上,提出了基于BERT(bidirectional encoder representations from transformers)模型的电网现场作业风险自动评级方法。考虑作业风险分级表的概括性,提出对作业风险分级表进行文本增强;考虑实际现场历史文本库中存在一定比例的冗余内容和错误评级,提出冗余文本去除方法和基于文本挖掘技术的风险等级纠错方法;以经过上述方法处理后的2类现场作业文本为样本,构建了基于BERT单文本主题分类微调模型的文本分类模型,实现了对电网现场作业风险的自动评级。算例对比了该文模型与其他分类模型在不同样本集下的评级效果,表明BERT模型能够更全面地获取作业文本的语义特征,分级表的文本增强方法和历史库的风险等级纠错方法能提升评级效果,而冗余文本去除会导致作业文本样本数量减少较多,反而降低评级效果。上述结果表明,该文方法能够实现电网现场作业文本的自动评级,并具有较高的准确性。展开更多
基金supported by a grant from the Wuhan Science and Technology Program of China(No.2014060101010032)
文摘This study was to investigate the changes of autonomic nerve function and hemodynamics in patients with vasovagal syncope(VVS) during head-up tilt-table testing(HUT). HUT was performed in 68 patients with unexplained syncope and 18 healthy subjects served as control group. According to whether bradycardia, hypotension or both took place during the onset of syncope, the patients were divided during the test into three subgroups: vasodepressor syncope(VD), cardioinhibitory syncope(CI) and mixed syncope(MX) subgroups. Heart rate, blood pressure, heart rate variability(HRV), and deceleration capacity(DC) were continuously analyzed during HUT. For all the subjects with positive responses, the normalized low frequency(LFn) and the LF/HF ratio markedly decreased whereas normalized high frequency(HFn) increased when syncope occurred. Syncopal period also caused more significant increase in the power of the DC in positive groups. These changes were more exaggerated compared to controls. All the patients were indicative of a sympathetic surge in the presence of withdrawal vagal activity before syncope and a sympathetic inhibition with a vagal predominance at the syncopal stage by the frequency-domain analysis of HRV. With the measurements of DC, a decreased vagal tone before syncope stage and a vagal activation at the syncopal stage were observed. The vagal tone was higher in subjects showing cardioinhibitory responses at the syncopal stage. DC may provide an alternative method to understand the autonomic profile of VVS patients.
文摘Differences in transpiration and leaf water potential （LWP） in relation to cassava yield were investigated along inland valley toposequence in a 4×4 Latin square design. The landrace with the highest transpiration rate and lowest LWP yielded the lowest, while TMS 91/02324 and TMS 91/02327 with intermediate rate and highest LWP yielded the highest, indicating that high transpiration rate associated with low LWP reduced yield. Transpiration was lower in the fringe with deeper water table than valley bottom at deep water table site, while at shallow water table, it was higher in the fringe than valley bottom, suggesting that drought and excess moisture reduced transpiration. LWP and water table depth correlated negatively indicating that shallow water table reduced transpiration by reducing LWP. Transpiration increased and LWP decreased as radiation, leaf temperature and vapour pressure deficit increased and differences in these microclimatic conditions caused differences in the two processes between sites, years and time of day. Under mild water stress, transpiration and LWP were higher in the afternoon than the morning, but the reverse occurred under severe stress. TMS 91/02324 and TMS 91/02327 had the highest LWP under severe stress, indicating their higher drought tolerance than the other cultivars.
文摘电网现场作业风险等级影响着作业的安全性和经济性,目前风险等级评级主要依赖于人工评级,存在一定的错误率。以国网公司的作业风险分级表与实际现场历史文本库作为研究对象,在充分分析各自文本特点的基础上,提出了基于BERT(bidirectional encoder representations from transformers)模型的电网现场作业风险自动评级方法。考虑作业风险分级表的概括性,提出对作业风险分级表进行文本增强;考虑实际现场历史文本库中存在一定比例的冗余内容和错误评级,提出冗余文本去除方法和基于文本挖掘技术的风险等级纠错方法;以经过上述方法处理后的2类现场作业文本为样本,构建了基于BERT单文本主题分类微调模型的文本分类模型,实现了对电网现场作业风险的自动评级。算例对比了该文模型与其他分类模型在不同样本集下的评级效果,表明BERT模型能够更全面地获取作业文本的语义特征,分级表的文本增强方法和历史库的风险等级纠错方法能提升评级效果,而冗余文本去除会导致作业文本样本数量减少较多,反而降低评级效果。上述结果表明,该文方法能够实现电网现场作业文本的自动评级,并具有较高的准确性。
