Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy expenditure.Methods: Using a within-participants repeated measures design, 11 healthy young-adult f...Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy expenditure.Methods: Using a within-participants repeated measures design, 11 healthy young-adult females(age = 20.0 ± 1.8 years) were measured using indirect calorimetry to assess energy expenditure, and electromyography to assess muscular activation in trunk and leg musculature under 3different sitting surfaces: flat-firm surface, air-filled cushion, and a stability ball. Data were analyzed using repeated measures analysis of variance with follow-up pairwise contrasts used to determine the specific effects of sitting surface on muscle activation and energy expenditure.Results: Significantly greater energy expenditure was recorded for the stability ball(p = 0.01) and the cushion(p = 0.03) over the flat surface(10.4% and 9.6% greater, respectively), with no differences between the ball and the cushion. Both the ball and the cushion produced higher tibialis anterior activation over the flat surface(1.09 and 0.63 root-mean-square millivolts(RMSmv), respectively), while the stability ball produced higher soleus activity over both cushion and flat surfaces(3.97 and 4.24 RMSmv, respectively). Additionally, the cushion elicited higher adductor longus activity over the ball and flat surfaces(1.76 and 1.81 RMSmv, respectively), but no trunk musculature differences were revealed.Conclusion: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric expenditure.Given the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.展开更多
For a class of linear discrete-time systems whose states can not be measured directly, an approach to designing the constrained controller based on state estimation was proposed. By constructing a proper linear state ...For a class of linear discrete-time systems whose states can not be measured directly, an approach to designing the constrained controller based on state estimation was proposed. By constructing a proper linear state observer for the controlled system, the sufficient condition to convergence of the state error was derived. Under a simple assumption on the initial state error, we presented an LMI-based method to design the constrained feedback gain and the observer gain. An example was used to illustrate our results.展开更多
The structure and energy of the carbonium ions formed upon protonation of butane were studied by the DFT methods. Four stable structures are identified for the protonated form of n-butane, the energy increases in the ...The structure and energy of the carbonium ions formed upon protonation of butane were studied by the DFT methods. Four stable structures are identified for the protonated form of n-butane, the energy increases in the following order： C2HC3〈C1HC2〈C2HH〈C1HH, and the stability decreases in the following order C2HC3〉C1HC2〉C2HH〉C1HH. The stability of the penta-coordinated carbonium ions may be explained by the electron distribution in the three-center-two-electron bonds. The delocalization of the penta-coordinated carbonium ion CHC with three-center-two-electron bonds on positive charges was stronger than that of the penta-coordinated earbonium ion CHH with three-center-two-electron bonds and its stability was higher than that of the penta-coordinated carbonium ion CHH with three-center-two-electron bonds.展开更多
Sugarcane advanced variety trials are planted across several locations and harvested for several crop-years to determine genotype by environment interaction and yield stability. Previous studies describe methods for s...Sugarcane advanced variety trials are planted across several locations and harvested for several crop-years to determine genotype by environment interaction and yield stability. Previous studies describe methods for simultaneous screening for yield and stability but did not use parametric statistical tests for comparing genotypes. The objective of this study was to describe a parametric statistical method for simultaneous screening of sugarcane genotypes for yield and stability. Data from 26 crops were collected from trials established at five locations and harvested in the plant, first, second, third and fourth ratoon crops. The mixed procedure of SAS was used for data analysis. The intercept and slope were used to represent yield and stability, respectively. There were significant （P 〈 0.05） differences in yield and stability among the genotypes. Test genotypes were classified into groups of genotypes that produced high yield, or high stability or both. The method provides fast statistical tests for simultaneous screening for yield and stability. The method was also used to compare two genotypes, an application for variety choice at time of release.展开更多
Previous research on the relationship between audit partner tenure and audit quality assumed that auditors conducted auditing works in a stable external environment where the corporate and management behavior was high...Previous research on the relationship between audit partner tenure and audit quality assumed that auditors conducted auditing works in a stable external environment where the corporate and management behavior was highly predictable. This study uses the joint tenure between audit partners and management to explain audit quality, because corporate directors would consider an appropriate adjustment in the management to deal with a dramatic change in the external environment. First, we examined whether there is a significant association between audit partner tenure and audit quality after the implementation of mandatory audit partner rotation by using the auditor tenure only. We addressed this issue by using a sample of Taiwan Residents companies and found no significant association between audit partner tenure and the magnitude of discretionary accruals （DA）, a common proxy for audit quality. Second, we tested the relationship between audit partner tenure and audit quality under the consideration of industry structure stability. The result exhibits a negative relation between audit partner tenure and audit quality under the control of industry structural stability which is measured by a proxy variable, the joint tenure between audit partner and management. Third, we investigated whether the association does exist between joint tenure of auditors and management and audit quality. We also addressed this issue by using Taiwan Residents data and found a significant association between the joint tenure of auditor and management and the magnitude of DA. Our findings provide evidence that the use of a mandatory rotation rule is an ineffective way to improve audit quality.展开更多
文摘Purpose: To test the effectiveness of sitting surfaces with varied amounts of stability on muscle activity and energy expenditure.Methods: Using a within-participants repeated measures design, 11 healthy young-adult females(age = 20.0 ± 1.8 years) were measured using indirect calorimetry to assess energy expenditure, and electromyography to assess muscular activation in trunk and leg musculature under 3different sitting surfaces: flat-firm surface, air-filled cushion, and a stability ball. Data were analyzed using repeated measures analysis of variance with follow-up pairwise contrasts used to determine the specific effects of sitting surface on muscle activation and energy expenditure.Results: Significantly greater energy expenditure was recorded for the stability ball(p = 0.01) and the cushion(p = 0.03) over the flat surface(10.4% and 9.6% greater, respectively), with no differences between the ball and the cushion. Both the ball and the cushion produced higher tibialis anterior activation over the flat surface(1.09 and 0.63 root-mean-square millivolts(RMSmv), respectively), while the stability ball produced higher soleus activity over both cushion and flat surfaces(3.97 and 4.24 RMSmv, respectively). Additionally, the cushion elicited higher adductor longus activity over the ball and flat surfaces(1.76 and 1.81 RMSmv, respectively), but no trunk musculature differences were revealed.Conclusion: Compliant surfaces resulted in higher levels of muscular activation in the lower extremities facilitating increased caloric expenditure.Given the increasing trends in sedentary careers and the increases in obesity, this is an important finding to validate the merits of active sitting facilitating increased caloric expenditure and muscle activation.
文摘For a class of linear discrete-time systems whose states can not be measured directly, an approach to designing the constrained controller based on state estimation was proposed. By constructing a proper linear state observer for the controlled system, the sufficient condition to convergence of the state error was derived. Under a simple assumption on the initial state error, we presented an LMI-based method to design the constrained feedback gain and the observer gain. An example was used to illustrate our results.
文摘The structure and energy of the carbonium ions formed upon protonation of butane were studied by the DFT methods. Four stable structures are identified for the protonated form of n-butane, the energy increases in the following order： C2HC3〈C1HC2〈C2HH〈C1HH, and the stability decreases in the following order C2HC3〉C1HC2〉C2HH〉C1HH. The stability of the penta-coordinated carbonium ions may be explained by the electron distribution in the three-center-two-electron bonds. The delocalization of the penta-coordinated carbonium ion CHC with three-center-two-electron bonds on positive charges was stronger than that of the penta-coordinated earbonium ion CHH with three-center-two-electron bonds and its stability was higher than that of the penta-coordinated carbonium ion CHH with three-center-two-electron bonds.
文摘Sugarcane advanced variety trials are planted across several locations and harvested for several crop-years to determine genotype by environment interaction and yield stability. Previous studies describe methods for simultaneous screening for yield and stability but did not use parametric statistical tests for comparing genotypes. The objective of this study was to describe a parametric statistical method for simultaneous screening of sugarcane genotypes for yield and stability. Data from 26 crops were collected from trials established at five locations and harvested in the plant, first, second, third and fourth ratoon crops. The mixed procedure of SAS was used for data analysis. The intercept and slope were used to represent yield and stability, respectively. There were significant （P 〈 0.05） differences in yield and stability among the genotypes. Test genotypes were classified into groups of genotypes that produced high yield, or high stability or both. The method provides fast statistical tests for simultaneous screening for yield and stability. The method was also used to compare two genotypes, an application for variety choice at time of release.
文摘Previous research on the relationship between audit partner tenure and audit quality assumed that auditors conducted auditing works in a stable external environment where the corporate and management behavior was highly predictable. This study uses the joint tenure between audit partners and management to explain audit quality, because corporate directors would consider an appropriate adjustment in the management to deal with a dramatic change in the external environment. First, we examined whether there is a significant association between audit partner tenure and audit quality after the implementation of mandatory audit partner rotation by using the auditor tenure only. We addressed this issue by using a sample of Taiwan Residents companies and found no significant association between audit partner tenure and the magnitude of discretionary accruals （DA）, a common proxy for audit quality. Second, we tested the relationship between audit partner tenure and audit quality under the consideration of industry structure stability. The result exhibits a negative relation between audit partner tenure and audit quality under the control of industry structural stability which is measured by a proxy variable, the joint tenure between audit partner and management. Third, we investigated whether the association does exist between joint tenure of auditors and management and audit quality. We also addressed this issue by using Taiwan Residents data and found a significant association between the joint tenure of auditor and management and the magnitude of DA. Our findings provide evidence that the use of a mandatory rotation rule is an ineffective way to improve audit quality.
