Early detection of sudden cardiac death may be used for surviving the life of cardiac patients. In this paper we have investigated an algorithm to detect and predict sudden cardiac death, by processing of heart rate v...Early detection of sudden cardiac death may be used for surviving the life of cardiac patients. In this paper we have investigated an algorithm to detect and predict sudden cardiac death, by processing of heart rate variability signal through the classical and time-frequency methods. At first, one minute of ECG signals, just before the cardiac death event are extracted and used to compute heart rate variability (HRV) signal. Five features in time domain and four features in frequency domain are extracted from the HRV signal and used as classical linear features. Then the Wigner Ville transform is applied to the HRV signal, and 11 extra features in the time-frequency (TF) domain are obtained. In order to improve the performance of classification, the principal component analysis (PCA) is applied to the obtained features vector. Finally a neural network classifier is applied to the reduced features. The obtained results show that the TF method can classify normal and SCD subjects, more efficiently than the classical methods. A MIT-BIH ECG database was used to evaluate the proposed method. The proposed method was implemented using MLP classifier and had 74.36% and 99.16% correct detection rate (accuracy) for classical features and TF method, respectively. Also, the accuracy of the KNN classifier were 73.87% and 96.04%.展开更多
目的定量评估高温热浪与居民猝死之间的暴露—反应关系,量化其超额死亡,并探究潜在的脆弱人群。方法以江苏省2015—2021年间猝死居民为研究对象开展时间分层病例交叉研究,利用中国气象局陆面数据同化系统(China Meteorological Administ...目的定量评估高温热浪与居民猝死之间的暴露—反应关系,量化其超额死亡,并探究潜在的脆弱人群。方法以江苏省2015—2021年间猝死居民为研究对象开展时间分层病例交叉研究,利用中国气象局陆面数据同化系统(China Meteorological Administration Land Data Assimilation System,CLDAS V2.0)温度数据识别江苏省不同定义下的高温热浪事件(结合相对温度阈值和持续时间进行定义),根据死亡日期和生前家庭住址评估研究对象的高温热浪暴露情况,采用条件logistic回归模型和分布滞后非线性模型(Distributed Lag Nonlinear Model,DLNM)评估高温热浪与猝死之间的暴露—反应关系,估算可归因于高温热浪暴露的超额死亡,根据性别和年龄进行分层分析并探讨其效应修饰作用。结果所有不同定义下的高温热浪暴露均与猝死风险增加有关,且随高温热浪强度增加,其猝死风险也随之增加。以P95_3d定义(温度超过第95百分位数且持续至少3 d)为例,高温热浪的人群猝死风险升高56%(95%CI:31%~86%),可归因于高温热浪暴露的猝死占总猝死人群的1.19%(95%CI:0.77%~1.58%)。分层分析结果提示,高温热浪暴露与猝死之间的关联在不同年龄和性别组中无显著差异。结论高温热浪暴露与猝死风险增加有关,在夏季减少热浪暴露可能有助于降低猝死的发生风险。展开更多
Based on the alternation of scenes,awareness of time is analyzed from three perspectives.The common one is to be aware of time flow in the change of scenes.The outstanding ones include the psychological and philosophi...Based on the alternation of scenes,awareness of time is analyzed from three perspectives.The common one is to be aware of time flow in the change of scenes.The outstanding ones include the psychological and philosophical perception of time.Being aware of the temporality of life,the individual need to take an open and unforced attitude toward death -"carpe diem!".展开更多
AIM:To identify a hypothesis on:Supine sleep,sudden infant death syndrome(SIDS) reduction and association with increasing autism incidence.METHODS:Literature was searched for autism spectrum disorder incidence time tr...AIM:To identify a hypothesis on:Supine sleep,sudden infant death syndrome(SIDS) reduction and association with increasing autism incidence.METHODS:Literature was searched for autism spectrum disorder incidence time trends,with correlation of change-points matching supine sleep campaigns.A mechanistic model expanding the hypothesis was constructed based on further review of epidemiological and other literature on autism.RESULTS:In five countries(Denmark,United Kingdom,Australia,Israel,United States) with published time trends of autism,change-points coinciding with supine sleep campaigns were identified.The model proposes that supine sleep does not directly cause autism,but increases the likelihood of expression of a subset of autistic criteria in individuals with genetic susceptibility,thereby specifically increasing the incidence of autism without intellectual disability.CONCLUSION:Supine sleep is likely a physiological stressor,that does reduce SIDS,but at the cost of impact on emotional and social development in the population,a portion of which will be susceptible to,and consequently express autism.A re-evaluation of all benefits and harms of supine sleep is warranted.If the SIDS mechanism proposed and autism model presented can be verified,the research agenda may be better directed,in order to further decrease SIDS,and reduce autism incidence.展开更多
A new stochastic epidemic model, that is, a general continuous time birth and death chain model, is formulated based on a deterministic model including vaccination. We use continuous time Markov chain to construct the...A new stochastic epidemic model, that is, a general continuous time birth and death chain model, is formulated based on a deterministic model including vaccination. We use continuous time Markov chain to construct the birth and death process. Through the Kolmogorov forward equation and the theory of moment generating function, the corresponding population expectations are studied. The theoretical result of the stochastic model and deterministic version is also given. Finally, numerical simulations are carried out to substantiate the theoretical results of random walk.展开更多
文摘Early detection of sudden cardiac death may be used for surviving the life of cardiac patients. In this paper we have investigated an algorithm to detect and predict sudden cardiac death, by processing of heart rate variability signal through the classical and time-frequency methods. At first, one minute of ECG signals, just before the cardiac death event are extracted and used to compute heart rate variability (HRV) signal. Five features in time domain and four features in frequency domain are extracted from the HRV signal and used as classical linear features. Then the Wigner Ville transform is applied to the HRV signal, and 11 extra features in the time-frequency (TF) domain are obtained. In order to improve the performance of classification, the principal component analysis (PCA) is applied to the obtained features vector. Finally a neural network classifier is applied to the reduced features. The obtained results show that the TF method can classify normal and SCD subjects, more efficiently than the classical methods. A MIT-BIH ECG database was used to evaluate the proposed method. The proposed method was implemented using MLP classifier and had 74.36% and 99.16% correct detection rate (accuracy) for classical features and TF method, respectively. Also, the accuracy of the KNN classifier were 73.87% and 96.04%.
文摘目的定量评估高温热浪与居民猝死之间的暴露—反应关系,量化其超额死亡,并探究潜在的脆弱人群。方法以江苏省2015—2021年间猝死居民为研究对象开展时间分层病例交叉研究,利用中国气象局陆面数据同化系统(China Meteorological Administration Land Data Assimilation System,CLDAS V2.0)温度数据识别江苏省不同定义下的高温热浪事件(结合相对温度阈值和持续时间进行定义),根据死亡日期和生前家庭住址评估研究对象的高温热浪暴露情况,采用条件logistic回归模型和分布滞后非线性模型(Distributed Lag Nonlinear Model,DLNM)评估高温热浪与猝死之间的暴露—反应关系,估算可归因于高温热浪暴露的超额死亡,根据性别和年龄进行分层分析并探讨其效应修饰作用。结果所有不同定义下的高温热浪暴露均与猝死风险增加有关,且随高温热浪强度增加,其猝死风险也随之增加。以P95_3d定义(温度超过第95百分位数且持续至少3 d)为例,高温热浪的人群猝死风险升高56%(95%CI:31%~86%),可归因于高温热浪暴露的猝死占总猝死人群的1.19%(95%CI:0.77%~1.58%)。分层分析结果提示,高温热浪暴露与猝死之间的关联在不同年龄和性别组中无显著差异。结论高温热浪暴露与猝死风险增加有关,在夏季减少热浪暴露可能有助于降低猝死的发生风险。
文摘Based on the alternation of scenes,awareness of time is analyzed from three perspectives.The common one is to be aware of time flow in the change of scenes.The outstanding ones include the psychological and philosophical perception of time.Being aware of the temporality of life,the individual need to take an open and unforced attitude toward death -"carpe diem!".
文摘AIM:To identify a hypothesis on:Supine sleep,sudden infant death syndrome(SIDS) reduction and association with increasing autism incidence.METHODS:Literature was searched for autism spectrum disorder incidence time trends,with correlation of change-points matching supine sleep campaigns.A mechanistic model expanding the hypothesis was constructed based on further review of epidemiological and other literature on autism.RESULTS:In five countries(Denmark,United Kingdom,Australia,Israel,United States) with published time trends of autism,change-points coinciding with supine sleep campaigns were identified.The model proposes that supine sleep does not directly cause autism,but increases the likelihood of expression of a subset of autistic criteria in individuals with genetic susceptibility,thereby specifically increasing the incidence of autism without intellectual disability.CONCLUSION:Supine sleep is likely a physiological stressor,that does reduce SIDS,but at the cost of impact on emotional and social development in the population,a portion of which will be susceptible to,and consequently express autism.A re-evaluation of all benefits and harms of supine sleep is warranted.If the SIDS mechanism proposed and autism model presented can be verified,the research agenda may be better directed,in order to further decrease SIDS,and reduce autism incidence.
文摘A new stochastic epidemic model, that is, a general continuous time birth and death chain model, is formulated based on a deterministic model including vaccination. We use continuous time Markov chain to construct the birth and death process. Through the Kolmogorov forward equation and the theory of moment generating function, the corresponding population expectations are studied. The theoretical result of the stochastic model and deterministic version is also given. Finally, numerical simulations are carried out to substantiate the theoretical results of random walk.
