Psychophysical studies suggest that lateral extrastriate visual cortical areas in cats may mediate the sparing of vision largely by network reorganization following lesions of early visual cortical areas. To date, how...Psychophysical studies suggest that lateral extrastriate visual cortical areas in cats may mediate the sparing of vision largely by network reorganization following lesions of early visual cortical areas. To date, however, there is little direct physiological evidence to support this hypothesis. Using in vivo single-anit recording techniques, we examined the response of neurons in areas 19, 21, and 20 to different types of visual stimulation in cats with or without acute bilateral lesions in areas 17 and 18. Our results showed that, relative to the controls, acute lesions inactivated the response of 99.3% of neurons to moving gratings and 93% of neurons to flickering square stimuli＇in areas 19, 21, and 20. These results indicated that acute lesions of primary visual areas in adult eats may impair most visual abilities. Sparing of vision in cats with neonatal lesions in early visual cortical areas may result largely from a postoperative reorganization of visual pathways from subcortical nucleus to extrastriate visual cortical areas.展开更多
Predicting damage to vibration isolators in a raft experiencing heavy shock loadings from explosions is an important task when designing a raft system. It is also vital to be able to research the vulnerability of heav...Predicting damage to vibration isolators in a raft experiencing heavy shock loadings from explosions is an important task when designing a raft system. It is also vital to be able to research the vulnerability of heavily shocked floating rafts unreliable, especially when the allowable values The conventional approach to prediction has been or ultimate values of vibration isolators of supposedly uniform standard in a raft actually have differing and uncertain values due to defective workmanship. A new model for predicting damage to vibration isolators in a shocked floating raft system is presented in this paper. It is based on a support vector machine（SVM）, which uses Artificial Intelligence to characterize complicated nonlinear mapping between the impacting environment and damage to the vibration isolators. The effectiveness of the new method for predicting damage was illustrated by numerical simulations, and shown to be effective when relevant parameters of the model were chosen reasonably. The effect determining parameters, including kernel function and penalty factors, has on prediction results is also discussed. It can be concluded that the SVM will probably become a valid tool to study damage or vulnerability in a shocked raft system.展开更多
Background:The effect of hamstring flexibility on the peak hamstring muscle strains in sprinting,until now,remained unknown,which limited our understanding of risk factors of hamstring muscle strain injury(hamstring i...Background:The effect of hamstring flexibility on the peak hamstring muscle strains in sprinting,until now,remained unknown,which limited our understanding of risk factors of hamstring muscle strain injury(hamstring injury).As a continuation of our previous study,this study was aimed to examine the relationship between hamstring flexibility and peak hamstring muscle strains in sprinting.Methods:Ten male and 10 female college students participated in this study.Hamstring flexibility,isokinetic strength data,three-dimensional(3D)kinematic data in a hamstring isokinetic test,and kinematic data in a sprinting test were collected for each participant.The optimal hamstring muscle lengths and peak hamstring muscle strains in sprinting were determined for each participant.Results:The muscle strain of each of the 3 biarticulated hamstring muscles reached a peak during the late swing phase.Peak hamstring muscle strains were negatively correlated to hamstring flexibility(0.1179 ≤ R2≤ 0.4519,p = 0.001) but not to hip and knee joint positions at the time of peak hamstring muscle strains.Peak hamstring muscle strains were not different for different genders.Peak muscle strains of biceps long head(0.071 ± 0.059) and semitendinosus(0.070 ± 0.055) were significantly greater than that of semimembranosus(0.064 ± 0.054).Conclusion:A potential for hamstring injury exists during the late swing phase of sprinting.Peak hamstring muscle strains in sprinting are negatively correlated to hamstring flexibility across individuals.The magnitude of peak muscle strains is different among hamstring muscles in sprinting,which may explain the different injury rate among hamstring muscles.展开更多
基金National Natural Science Foundation of China (31171082)Natural Science Foundation of Anhui Province (070413138)Key Research Foundation of Anhui Province Education Department (KJ2009A167)
文摘Psychophysical studies suggest that lateral extrastriate visual cortical areas in cats may mediate the sparing of vision largely by network reorganization following lesions of early visual cortical areas. To date, however, there is little direct physiological evidence to support this hypothesis. Using in vivo single-anit recording techniques, we examined the response of neurons in areas 19, 21, and 20 to different types of visual stimulation in cats with or without acute bilateral lesions in areas 17 and 18. Our results showed that, relative to the controls, acute lesions inactivated the response of 99.3% of neurons to moving gratings and 93% of neurons to flickering square stimuli＇in areas 19, 21, and 20. These results indicated that acute lesions of primary visual areas in adult eats may impair most visual abilities. Sparing of vision in cats with neonatal lesions in early visual cortical areas may result largely from a postoperative reorganization of visual pathways from subcortical nucleus to extrastriate visual cortical areas.
文摘Predicting damage to vibration isolators in a raft experiencing heavy shock loadings from explosions is an important task when designing a raft system. It is also vital to be able to research the vulnerability of heavily shocked floating rafts unreliable, especially when the allowable values The conventional approach to prediction has been or ultimate values of vibration isolators of supposedly uniform standard in a raft actually have differing and uncertain values due to defective workmanship. A new model for predicting damage to vibration isolators in a shocked floating raft system is presented in this paper. It is based on a support vector machine（SVM）, which uses Artificial Intelligence to characterize complicated nonlinear mapping between the impacting environment and damage to the vibration isolators. The effectiveness of the new method for predicting damage was illustrated by numerical simulations, and shown to be effective when relevant parameters of the model were chosen reasonably. The effect determining parameters, including kernel function and penalty factors, has on prediction results is also discussed. It can be concluded that the SVM will probably become a valid tool to study damage or vulnerability in a shocked raft system.
基金supported by the National Natural Science Foundation of China(No.81572212)the Fundamental Research Funds for the Central Universities of China(No.2016BS013)
文摘Background:The effect of hamstring flexibility on the peak hamstring muscle strains in sprinting,until now,remained unknown,which limited our understanding of risk factors of hamstring muscle strain injury(hamstring injury).As a continuation of our previous study,this study was aimed to examine the relationship between hamstring flexibility and peak hamstring muscle strains in sprinting.Methods:Ten male and 10 female college students participated in this study.Hamstring flexibility,isokinetic strength data,three-dimensional(3D)kinematic data in a hamstring isokinetic test,and kinematic data in a sprinting test were collected for each participant.The optimal hamstring muscle lengths and peak hamstring muscle strains in sprinting were determined for each participant.Results:The muscle strain of each of the 3 biarticulated hamstring muscles reached a peak during the late swing phase.Peak hamstring muscle strains were negatively correlated to hamstring flexibility(0.1179 ≤ R2≤ 0.4519,p = 0.001) but not to hip and knee joint positions at the time of peak hamstring muscle strains.Peak hamstring muscle strains were not different for different genders.Peak muscle strains of biceps long head(0.071 ± 0.059) and semitendinosus(0.070 ± 0.055) were significantly greater than that of semimembranosus(0.064 ± 0.054).Conclusion:A potential for hamstring injury exists during the late swing phase of sprinting.Peak hamstring muscle strains in sprinting are negatively correlated to hamstring flexibility across individuals.The magnitude of peak muscle strains is different among hamstring muscles in sprinting,which may explain the different injury rate among hamstring muscles.
