THE STRATEGY OF MUSCULAR PRE-TENSION DURING INITIAL BLOCK PHASE IN SWIMMING GRAB START

The purpose of this study was to examine the effects of muscular pre-tension on swimming grab start performance. Eight well-trained subjects participated in this study. They were instructed to perform three strategies (stretch-shortening cycle, purely concentric with and with no muscular pre-tension) in grab start. Two Peak-Performance high-speed video cameras operating at 120 Hz and one Kistler force plate (600 Hz) mounted on the starting block were synchronized to collect the data. The results showed that the block time was significantly shorter and horizontal velocity of taking off was larger in muscular pre-tension than in stretch-shortening cycle strategy. Based on the results of the present study, it has been suggested that using muscular pre-tension strategy during initial block phase in grab start could add some benefits of decreasing time

The Impact of Sleep Apnea on Conventional Doppler Indices

AbstractObjectiveTo prospectively explore the impact of obstructive sleep apnea (OSA) on conventional Doppler indices and to identify possible negative prognostic factors for left ventricular diastolic dysfunction. Materials and Methods: All included subjects had overnight polysomnog-raphy. All subjects underwent a comprehensive echocardiography examination to evaluate systolic and diastolic function of the left ventricle. A multiple logistic regression model was created to identify potential negative prognostic factors for left ventricular dysfunction.ResultsA significant decrease in the ratio of early and atrial mitral flow velocity (E/A ratio) in OSA patients was found. Patients with moderate-to-severe OSA had a significant increase in the odds ratio for development of an abnormal E/A ratio (p=0.014, multivariate logistic regression). There was a significant negative correlation between E/A ratio and apnea-hypopnea index (p = 0.01). Non-obese OSA patients and obese-OSA patients carried significantly increased odds ratios for the development of a reduced E/A ratio (p = 0.02 and 0.038, respectively).ConclusionSubjects with OSA had reduced mitral E/A ratios, which implies possible impaired diastolic heart function. Further study to reverse impaired diastolic function via lifestyle modifications and treatment with nasal continuous positive airway pressure or surgery is warranted

The Association between Virus Prevalence and Intercolonial Aggression Levels in the Yellow Crazy Ant, Anoplolepis Gracilipes (Jerdon).

The recent discovery of multiple viruses in ants, along with the widespread infection of their hosts across geographic ranges, provides an excellent opportunity to test whether viral prevalence in the field is associated with the complexity of social interactions in the ant population. In this study, we examined whether the association exists between the field prevalence of a virus and the intercolonial aggression of its ant host, using the yellow crazy ant (Anoplolepis gracilipes) and its natural viral pathogen (TR44839 virus) as a model system. We delimitated the colony boundary and composition of A. gracilipes in a total of 12 study sites in Japan (Okinawa), Taiwan, and Malaysia (Penang), through intercolonial aggression assay. The spatial distribution and prevalence level of the virus was then mapped for each site. The virus occurred at a high prevalence in the surveyed colonies of Okinawa and Taiwan (100% infection rate across all sites), whereas virus prevalence was variable (30%-100%) or none (0%) at the sites in Penang. Coincidentally, colonies in Okinawa and Taiwan displayed a weak intercolonial boundary, as aggression between colonies is generally low or moderate. Contrastingly, sites in Penang were found to harbor a high proportion of mutually aggressive colonies, a pattern potentially indicative of complex colony composition. Our statistical analyses further confirmed the observed correlation, implying that intercolonial interactions likely contribute as one of the effective facilitators of/barriers to virus prevalence in the field population of this ant species