In 1985,Public Health Reports published a series of papers prepared for a workshop sponsored by the Centers for Disease Control and Prevention(CDC).1 Building on the seminal work of Jeremy Morris and Ralph Paffenbarge...In 1985,Public Health Reports published a series of papers prepared for a workshop sponsored by the Centers for Disease Control and Prevention(CDC).1 Building on the seminal work of Jeremy Morris and Ralph Paffenbarger Jr.,who were among the first to use epidemiological methods to study physical activity(PA),2,3 the workshop itself was the result of a growing scientific understanding of the importance of“physical fitness and exercise for improving the health of the public”.展开更多
本文论述了用于极高可靠性供电要求的场合如芯片工厂的配电架构改良,单独内燃机驱动的柴油发电机组(下文简称柴发)作为后备电源进行供电保障优化为结合储能以及不间断电源(Uninterrupted Power Supply,下文简称UPS)相组合的供电保障,UP...本文论述了用于极高可靠性供电要求的场合如芯片工厂的配电架构改良,单独内燃机驱动的柴油发电机组(下文简称柴发)作为后备电源进行供电保障优化为结合储能以及不间断电源(Uninterrupted Power Supply,下文简称UPS)相组合的供电保障,UPS的接线拓扑分析以及采用预充磁装置对优化的拓扑进行进一步改良。展开更多
Markov modeling of HIV/AIDS progression was done under the assumption that the state holding time (waiting time) had a constant hazard. This paper discusses the properties of the hazard function of the Exponential dis...Markov modeling of HIV/AIDS progression was done under the assumption that the state holding time (waiting time) had a constant hazard. This paper discusses the properties of the hazard function of the Exponential distributions and its modifications namely;Parameter proportion hazard (PH) and Accelerated failure time models (AFT) and their effectiveness in modeling the state holding time in Markov modeling of HIV/AIDS progression with and without risk factors. Patients were categorized by gender and age with female gender being the baseline. Data simulated using R software was fitted to each model, and the model parameters were estimated. The estimated P and Z values were then used to test the null hypothesis that the state waiting time data followed an Exponential distribution. Model identification criteria;Akaike information criteria (AIC), Bayesian information criteria (BIC), log-likelihood (LL), and R2 were used to evaluate the performance of the models. For the Survival Regression model, P and Z values supported the non-rejection of the null hypothesis for mixed gender without interaction and supported the rejection of the same for mixed gender with interaction term and males aged 50 - 60 years. Both Parameters supported the non-rejection of the null hypothesis in the rest of the age groups. For Gender male with interaction both P and Z values supported rejection in all the age groups except the age group 20 - 30 years. For Cox Proportional hazard and AFT models, both P and Z values supported the non-rejection of the null hypothesis across all age groups. The P-values for the three models supported different decisions for and against the Null hypothesis with AFT and Cox values supporting similar decisions in most of the age groups. Among the models considered, the regression assumption provided a superior fit based on (AIC), (BIC), (LL), and R2 Model identification criteria. This was particularly evident in age and gender subgroups where the data exhibited non-proportional hazards and violated the assumptions required for the Cox Proportional Hazard model. Moreover, the simplicity of the regression model, along with its ability to capture essential state transitions without over fitting, made it a more appropriate choice.展开更多
Two new freshwater atyid shrimps, Caridina angustipes sp nov.and C clavipes sp nov.from Hunan Province,China are described. C angustipes sp nov.is similar to C baojingensis Guo,He et Bai,1992,b...Two new freshwater atyid shrimps, Caridina angustipes sp nov.and C clavipes sp nov.from Hunan Province,China are described. C angustipes sp nov.is similar to C baojingensis Guo,He et Bai,1992,but with longer rostrum,15-27 dorsal teeth,3-6 ventral teeth,and straighter inner margin of endopods in male 1st pleopods. C clavipes sp nov.is similar to C angustipes ,but with narrower distal and fewer spines on inner margin of endopds in male 1st pleopods,and shorter and thinner appendix masculina in male 2nd pleopods with only 1 spine on inner lateral margin and 4 spines in apex.The holotypes are deposited in Shanghai Fisheries University.Some representative paratypes are deposited in Foshan Science and Technology College.展开更多
Presented in this paper is a semi active vibration control strategy based on the vibration absorber with adjustable clearance in elastic component. The control law of the clearance for alleviating the vibration of pr...Presented in this paper is a semi active vibration control strategy based on the vibration absorber with adjustable clearance in elastic component. The control law of the clearance for alleviating the vibration of primary system is derived by means of harmonic balancing technique so that the working frequency of the vibration absorber can trace the frequency variation of the harmonic excitation. The efficacy of the strategy is demonstrated by numerical simulations for attenuating the steady state vibration of a SDOF system and a 2 DOF system, which are under the harmonic excitation with slowly varied frequency in a wide range.展开更多
文摘In 1985,Public Health Reports published a series of papers prepared for a workshop sponsored by the Centers for Disease Control and Prevention(CDC).1 Building on the seminal work of Jeremy Morris and Ralph Paffenbarger Jr.,who were among the first to use epidemiological methods to study physical activity(PA),2,3 the workshop itself was the result of a growing scientific understanding of the importance of“physical fitness and exercise for improving the health of the public”.
文摘本文论述了用于极高可靠性供电要求的场合如芯片工厂的配电架构改良,单独内燃机驱动的柴油发电机组(下文简称柴发)作为后备电源进行供电保障优化为结合储能以及不间断电源(Uninterrupted Power Supply,下文简称UPS)相组合的供电保障,UPS的接线拓扑分析以及采用预充磁装置对优化的拓扑进行进一步改良。
文摘Markov modeling of HIV/AIDS progression was done under the assumption that the state holding time (waiting time) had a constant hazard. This paper discusses the properties of the hazard function of the Exponential distributions and its modifications namely;Parameter proportion hazard (PH) and Accelerated failure time models (AFT) and their effectiveness in modeling the state holding time in Markov modeling of HIV/AIDS progression with and without risk factors. Patients were categorized by gender and age with female gender being the baseline. Data simulated using R software was fitted to each model, and the model parameters were estimated. The estimated P and Z values were then used to test the null hypothesis that the state waiting time data followed an Exponential distribution. Model identification criteria;Akaike information criteria (AIC), Bayesian information criteria (BIC), log-likelihood (LL), and R2 were used to evaluate the performance of the models. For the Survival Regression model, P and Z values supported the non-rejection of the null hypothesis for mixed gender without interaction and supported the rejection of the same for mixed gender with interaction term and males aged 50 - 60 years. Both Parameters supported the non-rejection of the null hypothesis in the rest of the age groups. For Gender male with interaction both P and Z values supported rejection in all the age groups except the age group 20 - 30 years. For Cox Proportional hazard and AFT models, both P and Z values supported the non-rejection of the null hypothesis across all age groups. The P-values for the three models supported different decisions for and against the Null hypothesis with AFT and Cox values supporting similar decisions in most of the age groups. Among the models considered, the regression assumption provided a superior fit based on (AIC), (BIC), (LL), and R2 Model identification criteria. This was particularly evident in age and gender subgroups where the data exhibited non-proportional hazards and violated the assumptions required for the Cox Proportional Hazard model. Moreover, the simplicity of the regression model, along with its ability to capture essential state transitions without over fitting, made it a more appropriate choice.
文摘Two new freshwater atyid shrimps, Caridina angustipes sp nov.and C clavipes sp nov.from Hunan Province,China are described. C angustipes sp nov.is similar to C baojingensis Guo,He et Bai,1992,but with longer rostrum,15-27 dorsal teeth,3-6 ventral teeth,and straighter inner margin of endopods in male 1st pleopods. C clavipes sp nov.is similar to C angustipes ,but with narrower distal and fewer spines on inner margin of endopds in male 1st pleopods,and shorter and thinner appendix masculina in male 2nd pleopods with only 1 spine on inner lateral margin and 4 spines in apex.The holotypes are deposited in Shanghai Fisheries University.Some representative paratypes are deposited in Foshan Science and Technology College.
文摘Presented in this paper is a semi active vibration control strategy based on the vibration absorber with adjustable clearance in elastic component. The control law of the clearance for alleviating the vibration of primary system is derived by means of harmonic balancing technique so that the working frequency of the vibration absorber can trace the frequency variation of the harmonic excitation. The efficacy of the strategy is demonstrated by numerical simulations for attenuating the steady state vibration of a SDOF system and a 2 DOF system, which are under the harmonic excitation with slowly varied frequency in a wide range.
