Short-leg walking boots are a common intervention for acute and chronic lower extremity injury.Few studies have examined the neuromuscular adaptations associated with short-leg walking boots and no previous study has ...Short-leg walking boots are a common intervention for acute and chronic lower extremity injury.Few studies have examined the neuromuscular adaptations associated with short-leg walking boots and no previous study has investigated timing characteristics of muscle activation during gait.The purpose of the current study was to examine the timing and amplitudes of muscle activation of the extrinsic ankle musculature during walking in two types of short-leg walking boots.Methods:Eleven healthy young adults performed five level walking trials at a self-selected pace in each of three conditions:normal walking,Gait Walker and Equalizer short-leg walking boots.Ground reaction forces were collected from a force platform while surface electromyography (EMG)was collected from the tibialis anterior,peroneus longus and medial gastrocnemius.EMG signals were rectified and smoothed using the root mean squared with a 20-ms smoothing window and were normalized to the largest mean of the normal walking trials.A repeated measures analysis of variance was used to assess the effect of short-leg walking boots on the onset,duration and amplitude of muscle activation.Results:Short-leg walking boots were generally associated with earlier onsets of muscle activation and longer durations of muscle activation.However,there was no reduction in EMG amplitude.Conclusion:The findings of this study show that the induced alterations in muscle activation patterns may limit the short-leg walking boots.Copyright(C)2012,Shanghai University of Sport.Production and hosting by Elsevier B.V.All rights reserved.展开更多
With sales at a quarter of a trillion and over 1.3 million employees,Wal-Mart has been the biggest retailing success ever before.A lot of Wal-Mart’s success was attributed to the strong and pervasive culture at the c...With sales at a quarter of a trillion and over 1.3 million employees,Wal-Mart has been the biggest retailing success ever before.A lot of Wal-Mart’s success was attributed to the strong and pervasive culture at the company.China’s retailing industry should really learn something about corporate culture-building from this excellent enterprise,so that one day it would become a strong competitor both home and abroad in retailing industry.展开更多
Wal-Mart, the world famous retailing giant, set its foot on the land of China 17 years ago. Now despite of its success elsewhere as well as its confidence and ambition to"conquer"the vast market China which ...Wal-Mart, the world famous retailing giant, set its foot on the land of China 17 years ago. Now despite of its success elsewhere as well as its confidence and ambition to"conquer"the vast market China which shows great potential, Wal-Mart fails to reach its goal anyway. To be more exact, it is far from the goal. Considering its unexpected failure, this article mainly discusses why Wal-Mart has experienced such a hard time in China. The issue is analyzed from the following aspects, namely cultural dif ference, distribution, management and public relationship.展开更多
Based on a log-structured merge(LSM)tree,the key-value(KV)storage system can provide high reading performance and optimize random writing performance.It is widely used in modern data storage systems like e-commerce,on...Based on a log-structured merge(LSM)tree,the key-value(KV)storage system can provide high reading performance and optimize random writing performance.It is widely used in modern data storage systems like e-commerce,online analytics,and real-time communication.An LSM tree stores new KV data in the memory and flushes to disk in batches.To prevent data loss in memory if there is an unexpected crash,RocksDB appends updating data in the write-ahead log(WAL)before updating the memory.However,synchronous WAL significantly reduces writing performance.In this paper,we present a new WAL mechanism named MyWAL.It directly manages raw devices(or partitions)instead of saving data on a traditional file system.These can avoid useless metadata updating and write data sequentially on disks.Experimental results show that MyWAL can significantly improve the data writing performance of RocksDB compared to the traditional WAL for small KV data on solid-state disks(SSDs),as much as five to eight times faster.On non-volatile memory express soild-state drives(NVMe SSDs)and non-volatile memory(NVM),MyWAL can improve data writing performance by 10%–30%.Furthermore,the results of YCSB(Yahoo!Cloud Serving Benchmark)show that the latency decreased by 50%compared with SpanDB.展开更多
基金funded in part by a grant from DeRoyal Industries,Inc.,Powell,TN,USA
文摘Short-leg walking boots are a common intervention for acute and chronic lower extremity injury.Few studies have examined the neuromuscular adaptations associated with short-leg walking boots and no previous study has investigated timing characteristics of muscle activation during gait.The purpose of the current study was to examine the timing and amplitudes of muscle activation of the extrinsic ankle musculature during walking in two types of short-leg walking boots.Methods:Eleven healthy young adults performed five level walking trials at a self-selected pace in each of three conditions:normal walking,Gait Walker and Equalizer short-leg walking boots.Ground reaction forces were collected from a force platform while surface electromyography (EMG)was collected from the tibialis anterior,peroneus longus and medial gastrocnemius.EMG signals were rectified and smoothed using the root mean squared with a 20-ms smoothing window and were normalized to the largest mean of the normal walking trials.A repeated measures analysis of variance was used to assess the effect of short-leg walking boots on the onset,duration and amplitude of muscle activation.Results:Short-leg walking boots were generally associated with earlier onsets of muscle activation and longer durations of muscle activation.However,there was no reduction in EMG amplitude.Conclusion:The findings of this study show that the induced alterations in muscle activation patterns may limit the short-leg walking boots.Copyright(C)2012,Shanghai University of Sport.Production and hosting by Elsevier B.V.All rights reserved.
文摘With sales at a quarter of a trillion and over 1.3 million employees,Wal-Mart has been the biggest retailing success ever before.A lot of Wal-Mart’s success was attributed to the strong and pervasive culture at the company.China’s retailing industry should really learn something about corporate culture-building from this excellent enterprise,so that one day it would become a strong competitor both home and abroad in retailing industry.
文摘Wal-Mart, the world famous retailing giant, set its foot on the land of China 17 years ago. Now despite of its success elsewhere as well as its confidence and ambition to"conquer"the vast market China which shows great potential, Wal-Mart fails to reach its goal anyway. To be more exact, it is far from the goal. Considering its unexpected failure, this article mainly discusses why Wal-Mart has experienced such a hard time in China. The issue is analyzed from the following aspects, namely cultural dif ference, distribution, management and public relationship.
基金Project supported by the National Key Research and Development Project of China(No.2022YFB2702101)the Shaanxi Province Key Industrial Projects,China(Nos.2021ZDLGY03-02 and 2021ZDLGY03-08)the National Natural Science Foundation of China(No.92152301)。
文摘Based on a log-structured merge(LSM)tree,the key-value(KV)storage system can provide high reading performance and optimize random writing performance.It is widely used in modern data storage systems like e-commerce,online analytics,and real-time communication.An LSM tree stores new KV data in the memory and flushes to disk in batches.To prevent data loss in memory if there is an unexpected crash,RocksDB appends updating data in the write-ahead log(WAL)before updating the memory.However,synchronous WAL significantly reduces writing performance.In this paper,we present a new WAL mechanism named MyWAL.It directly manages raw devices(or partitions)instead of saving data on a traditional file system.These can avoid useless metadata updating and write data sequentially on disks.Experimental results show that MyWAL can significantly improve the data writing performance of RocksDB compared to the traditional WAL for small KV data on solid-state disks(SSDs),as much as five to eight times faster.On non-volatile memory express soild-state drives(NVMe SSDs)and non-volatile memory(NVM),MyWAL can improve data writing performance by 10%–30%.Furthermore,the results of YCSB(Yahoo!Cloud Serving Benchmark)show that the latency decreased by 50%compared with SpanDB.
