The multiple cause of death (MCOD) analysis is used to account for the full contribution of TB as a cause of death to South African mortality in 2008 that were coded using ICD10. Following a review of MCOD methods, a ...The multiple cause of death (MCOD) analysis is used to account for the full contribution of TB as a cause of death to South African mortality in 2008 that were coded using ICD10. Following a review of MCOD methods, a sufficient set of variables for use in MCOD and a new method of quantifying the severity of each cause of death are proposed. The results show that a total of 86,818 (14.3% of all deaths) were TB related, and within all deaths due to natural underlying causes, 86,373 (16.1%) were TB related. Furthermore, 42,581 (7.9%) were due to TB only, 6.0% had TB as an underlying cause along with other contributory causes and 2.0% had TB as a contributory cause. TB was mentioned as the underlying cause of death in 74,863 certificates or 13.9% of deaths due to natural underlying causes. Further analysis using multinomial baseline logit models, reveals that the relative odds of death in any demographic group compared with death in the baseline categories depend on the severity level of TB considered. It is proposed that the severity measure should be adopted when studying the contribution of all main causes of death to total mortality.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
The entanglement dynamics of system, where atoms A and B interact with single mode cavity fields a and b respectively, is studied. The interaction between atom A and cavity a may be described by using the typical Jayn...The entanglement dynamics of system, where atoms A and B interact with single mode cavity fields a and b respectively, is studied. The interaction between atom A and cavity a may be described by using the typical Jaynes Cummings model, while that between the atom B and cavity b filled with a Kerr medium is of a two-photon process. For a certain initial atom entanglement state, there is an entanglement sudden death effect between the two atoms. The Kerr medium in the cavity b can effectively prevent the undesirable entanglement sudden death from occurring. Also, from the viewpoint of the population dynamics, we discuss why the Kerr medium can do so.展开更多
目的构建并验证一个模型以预测肺癌脑转移(lung cancer with brain metastases,LCBM)患者确诊后三个月内死亡的风险。方法本研究纳入监测,流行病学和最终结果(Surveillance,Epidemiology and End Results,SEER)数据库内2010年1月至2015...目的构建并验证一个模型以预测肺癌脑转移(lung cancer with brain metastases,LCBM)患者确诊后三个月内死亡的风险。方法本研究纳入监测,流行病学和最终结果(Surveillance,Epidemiology and End Results,SEER)数据库内2010年1月至2015年12月期间确诊为LCBM的患者。以是否发生早期死亡为研究终点将患者分为早期死亡组和非早期死亡组。以8∶2为比例将数据分为训练集和验证集。在训练集上采用最小绝对值收缩和筛选算子(least absolute shrinkage and selection operator,LASSO)回归法筛选预测因子,并使用多因素Logistic回归构建预测模型并创建列线图。使用受试者工作特征(receiver operating characteristic,ROC)曲线、校准曲线和临床决策曲线(decision curve analysis,DCA)分别在训练集和验证集上评估模型性能。结果共纳入5035例患者,早期死亡发生率28.3%。LASSO回归筛选出13个变量,Logistic回归最终保留了13个与LCBM患者早期死亡相关的危险因素,包括年龄、从诊断到开始治疗时间、肿瘤大小、肿瘤部位、肿瘤分化程度和组织学类型、T分期、N分期、手术、放疗、化疗、肝转移和骨转移。验证集的一致性指数(concordance index,C-index)为0.84,校准曲线和DCA显示模型具有较好的预测效能和临床净效益。结论基于多因素Logistic回归构建的LCBM患者发生早期死亡的预测模型的区分度较好,能够为临床决策提供一定的帮助。展开更多
Extending the double Jaynes Cummings model to a more complicated case where the mode-mode competition is considered, we investigate the entanglement character of two isolated atoms by means of concurrence, and discuss...Extending the double Jaynes Cummings model to a more complicated case where the mode-mode competition is considered, we investigate the entanglement character of two isolated atoms by means of concurrence, and discuss the dependence of atom atom entanglement on the different initial state and the relative coupling strength between the atom and the corresponding cavity field. The results show that the amplitude and the period of the atom atom entanglement evolution can be controlled by the choice of initial state and relative coupling strength, respectively. We find that the phenomenon of entanglement sudden death （ESD） is sensitive to the initial conditions. The length of the time interval for zero entanglement depends not only on the initial degree of entanglement between two atoms but also on the relative coupling strength of atom field interaction. The ESD effect can be weakened by enhancing the mode-mode competition between the three- and single-photon processes.展开更多
We use receiver function, gravity, and magnetic data to image the deep structures of central Death Valley. Receiver function analysis suggests the Moho is 24 km deep in the central part of the basin and deepens to 33 ...We use receiver function, gravity, and magnetic data to image the deep structures of central Death Valley. Receiver function analysis suggests the Moho is 24 km deep in the central part of the basin and deepens to 33 km to the east and 31 km to the west. The estimated lower crustal density is 2900 kg/m3, which suggests a gabbroic composition, whereas the upper crustal density, excluding basin sediments, is estimated to average 2690 kg/m3 or approximately a quartzofeldspathic composition. We modeled the magnetic sources as upper crustal to suggest a relatively shallow Curie depth in this region of high heat flow. We developed models to test the hypothesis that a low-density, non-magnetic body (magma or fluid-rich material?) within the lower crust at a depth of 15 km could coincide with the location of the Death Valley bright spot imaged on a deep seismic reflection profile. Those models suggest that if there is a low density region in the mid to lower crust in the area of the bright spot, then the region is also likely to be underplated by mafic or ultramafic materials which may have contributed to heating, uplift, and thinning of the crust during extension.展开更多
Network storage provides high scalability, availability and flexibility for storage systems, and is widely applied to many fields. Particularly, I/O performance is of great significance. Its application is wide and ex...Network storage provides high scalability, availability and flexibility for storage systems, and is widely applied to many fields. Particularly, I/O performance is of great significance. Its application is wide and expanding rapidly. I/O performance has already become the bottleneck of the whole performance of computer systems for a long time, and under the condition of the present computer technology, I/O performance optimization method looks especially important. In the paper, I/O performance model was analyzed based on the combination of quasi birth, death process and queuing model, and then solved the model. A number of important related performance indicators and the relationship between them were given. By the way of example, this method can show the I/O performance more accurately. Finally, we got some useful conclusions, which may be used to evaluate network storage performance, and are the basis of confirming I/O scheduling strategy.展开更多
In this paper, the entanglement dynamics of a double two-photon Jaynes-Cummings model with Kerr-like medium is investigated. It is shown that initial entanglement has an interesting subsequent time evolution, includin...In this paper, the entanglement dynamics of a double two-photon Jaynes-Cummings model with Kerr-like medium is investigated. It is shown that initial entanglement has an interesting subsequent time evolution, including the so-called entanglement sudden death effect. It is also shown analytically that the Kerr-like medium can repress entanglement sudden death and enhance the degree of atom-atom entanglement. A more interesting fact is that the Kerr effect is more obvious when each of the two cavities with have the Kerr-like medium than only one of them with the Kerr-like medium.展开更多
Direct intercellular communication mediated by gap junctions constitutes a major regulatory platform in the control of hepatic homeostasis.Hepatocellular gap junctions are composed of two hemichannels of adjacent cell...Direct intercellular communication mediated by gap junctions constitutes a major regulatory platform in the control of hepatic homeostasis.Hepatocellular gap junctions are composed of two hemichannels of adjacent cells which are built up by connexin proteins,in casu Cx32.Mathieu Vinken,Pofessor at the Department of Toxicology of the Free University BrusselsBelgium,was one of the first investigators to demonstrate that hepatic connexin expression is controlled by epigenetic mechanisms.In particular,he found that inhibitors of histone deacetylase enzymes enhance Cx32 production and gap junction activity in cultures of primary hepatocytes,a finding that is of importance for liver-based in vitro modelling.Professor Dr.Mathieu Vinken's recent work is focussed on the elucidation of the role of connexin proteins and their channels in the hepatocyte life cycle.Specific attention is paid to apoptosis in this context,whereby it has been found that Cx32 hemichannels control the termination of induced cell death in cultures of primary hepatocytes. Overall,Professor Dr.Mathieu Vinken's research can be considered as an important contribution to the field of hepatic connexin physiology.展开更多
文摘The multiple cause of death (MCOD) analysis is used to account for the full contribution of TB as a cause of death to South African mortality in 2008 that were coded using ICD10. Following a review of MCOD methods, a sufficient set of variables for use in MCOD and a new method of quantifying the severity of each cause of death are proposed. The results show that a total of 86,818 (14.3% of all deaths) were TB related, and within all deaths due to natural underlying causes, 86,373 (16.1%) were TB related. Furthermore, 42,581 (7.9%) were due to TB only, 6.0% had TB as an underlying cause along with other contributory causes and 2.0% had TB as a contributory cause. TB was mentioned as the underlying cause of death in 74,863 certificates or 13.9% of deaths due to natural underlying causes. Further analysis using multinomial baseline logit models, reveals that the relative odds of death in any demographic group compared with death in the baseline categories depend on the severity level of TB considered. It is proposed that the severity measure should be adopted when studying the contribution of all main causes of death to total mortality.
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.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 10535010 and 10775123)the Research Foundation from Ministry of Education of China (contract No 20070284016)
文摘The entanglement dynamics of system, where atoms A and B interact with single mode cavity fields a and b respectively, is studied. The interaction between atom A and cavity a may be described by using the typical Jaynes Cummings model, while that between the atom B and cavity b filled with a Kerr medium is of a two-photon process. For a certain initial atom entanglement state, there is an entanglement sudden death effect between the two atoms. The Kerr medium in the cavity b can effectively prevent the undesirable entanglement sudden death from occurring. Also, from the viewpoint of the population dynamics, we discuss why the Kerr medium can do so.
文摘目的构建并验证一个模型以预测肺癌脑转移(lung cancer with brain metastases,LCBM)患者确诊后三个月内死亡的风险。方法本研究纳入监测,流行病学和最终结果(Surveillance,Epidemiology and End Results,SEER)数据库内2010年1月至2015年12月期间确诊为LCBM的患者。以是否发生早期死亡为研究终点将患者分为早期死亡组和非早期死亡组。以8∶2为比例将数据分为训练集和验证集。在训练集上采用最小绝对值收缩和筛选算子(least absolute shrinkage and selection operator,LASSO)回归法筛选预测因子,并使用多因素Logistic回归构建预测模型并创建列线图。使用受试者工作特征(receiver operating characteristic,ROC)曲线、校准曲线和临床决策曲线(decision curve analysis,DCA)分别在训练集和验证集上评估模型性能。结果共纳入5035例患者,早期死亡发生率28.3%。LASSO回归筛选出13个变量,Logistic回归最终保留了13个与LCBM患者早期死亡相关的危险因素,包括年龄、从诊断到开始治疗时间、肿瘤大小、肿瘤部位、肿瘤分化程度和组织学类型、T分期、N分期、手术、放疗、化疗、肝转移和骨转移。验证集的一致性指数(concordance index,C-index)为0.84,校准曲线和DCA显示模型具有较好的预测效能和临床净效益。结论基于多因素Logistic回归构建的LCBM患者发生早期死亡的预测模型的区分度较好,能够为临床决策提供一定的帮助。
基金Project supported by the National Natural Science Foundation of China (Grant No 10374025)the Foundation of Education Department of Hunan Province of China (Grant Nos 06A038 and 06C080)the Science and Technology Project of Zhanjiang City (Grant No 2008C10019)
文摘Extending the double Jaynes Cummings model to a more complicated case where the mode-mode competition is considered, we investigate the entanglement character of two isolated atoms by means of concurrence, and discuss the dependence of atom atom entanglement on the different initial state and the relative coupling strength between the atom and the corresponding cavity field. The results show that the amplitude and the period of the atom atom entanglement evolution can be controlled by the choice of initial state and relative coupling strength, respectively. We find that the phenomenon of entanglement sudden death （ESD） is sensitive to the initial conditions. The length of the time interval for zero entanglement depends not only on the initial degree of entanglement between two atoms but also on the relative coupling strength of atom field interaction. The ESD effect can be weakened by enhancing the mode-mode competition between the three- and single-photon processes.
文摘We use receiver function, gravity, and magnetic data to image the deep structures of central Death Valley. Receiver function analysis suggests the Moho is 24 km deep in the central part of the basin and deepens to 33 km to the east and 31 km to the west. The estimated lower crustal density is 2900 kg/m3, which suggests a gabbroic composition, whereas the upper crustal density, excluding basin sediments, is estimated to average 2690 kg/m3 or approximately a quartzofeldspathic composition. We modeled the magnetic sources as upper crustal to suggest a relatively shallow Curie depth in this region of high heat flow. We developed models to test the hypothesis that a low-density, non-magnetic body (magma or fluid-rich material?) within the lower crust at a depth of 15 km could coincide with the location of the Death Valley bright spot imaged on a deep seismic reflection profile. Those models suggest that if there is a low density region in the mid to lower crust in the area of the bright spot, then the region is also likely to be underplated by mafic or ultramafic materials which may have contributed to heating, uplift, and thinning of the crust during extension.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 61073047)the Fundamental Research Funds for the Central Universities(Grant No.HEUCFT1007andHEUCF100607)the State Key Laboratory of High-End Server & Storage Technology(Grant No.2009HSSA08)
文摘Network storage provides high scalability, availability and flexibility for storage systems, and is widely applied to many fields. Particularly, I/O performance is of great significance. Its application is wide and expanding rapidly. I/O performance has already become the bottleneck of the whole performance of computer systems for a long time, and under the condition of the present computer technology, I/O performance optimization method looks especially important. In the paper, I/O performance model was analyzed based on the combination of quasi birth, death process and queuing model, and then solved the model. A number of important related performance indicators and the relationship between them were given. By the way of example, this method can show the I/O performance more accurately. Finally, we got some useful conclusions, which may be used to evaluate network storage performance, and are the basis of confirming I/O scheduling strategy.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10374025)the Natural Science Foundation of Hunan Province of China (Grant No. 07JJ3013)the Education Ministry of Hunan Province of China (Grant No. 06A038)
文摘In this paper, the entanglement dynamics of a double two-photon Jaynes-Cummings model with Kerr-like medium is investigated. It is shown that initial entanglement has an interesting subsequent time evolution, including the so-called entanglement sudden death effect. It is also shown analytically that the Kerr-like medium can repress entanglement sudden death and enhance the degree of atom-atom entanglement. A more interesting fact is that the Kerr effect is more obvious when each of the two cavities with have the Kerr-like medium than only one of them with the Kerr-like medium.
基金supported by grants of the FWO,the research council of the VUB and the European Union
文摘Direct intercellular communication mediated by gap junctions constitutes a major regulatory platform in the control of hepatic homeostasis.Hepatocellular gap junctions are composed of two hemichannels of adjacent cells which are built up by connexin proteins,in casu Cx32.Mathieu Vinken,Pofessor at the Department of Toxicology of the Free University BrusselsBelgium,was one of the first investigators to demonstrate that hepatic connexin expression is controlled by epigenetic mechanisms.In particular,he found that inhibitors of histone deacetylase enzymes enhance Cx32 production and gap junction activity in cultures of primary hepatocytes,a finding that is of importance for liver-based in vitro modelling.Professor Dr.Mathieu Vinken's recent work is focussed on the elucidation of the role of connexin proteins and their channels in the hepatocyte life cycle.Specific attention is paid to apoptosis in this context,whereby it has been found that Cx32 hemichannels control the termination of induced cell death in cultures of primary hepatocytes. Overall,Professor Dr.Mathieu Vinken's research can be considered as an important contribution to the field of hepatic connexin physiology.
