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Research highlights: Our study is the first to explore the genetic composition of ancient Cryptomeria trees across a distribution range in China. Background and objectives: Cryptomeria japonica var. sinensis is a native forest species of China; it is widely planted in the south of the country to create forests and for wood production. Unlike Cryptomeria in Japan, genetic Chinese Cryptomeria has seldom been studied, although there is ample evidence of its great ecological and economic value. Materials and methods: Because of overcutting, natural populations are rare in the wild. In this study, we investigated seven ancient tree populations to explore the genetic composition of Chinese Cryptomeria through ddRAD-seq technology. Results: The results reveal a lower genetic variation but higher genetic differentiation (Ho = 0.143, FST = 0.1204) than Japanese Cryptomeria (Ho = 0.245, FST = 0.0455). The 86% within-population variation is based on an analysis of molecular variance (AMOVA). Significant excess heterozygosity was detected in three populations and some outlier loci were found; these were considered to be the consequence of selection or chance. Structure analysis and dendrogram construction divided the seven ancient tree populations into four groups corresponding to the geographical provinces in which the populations are located, but there was no obvious correlation between genetic distance and geographic distance. A demographic history analysis conducted by a Stairway Plot showed that the effective population size of Chinese Cryptomeria had experienced a continuing decline from the mid-Pleistocene to the present. Our findings suggest that the strong genetic drift caused by climate fluctuation and intense anthropogenic disturbance together contributed to the current low diversity and structure. Considering the species’ unfavorable conservation status, strategies are urgently required to preserve the remaining genetic resources.

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Objective To explore the optimal frequency of whole-body vibration training for improving the balance and physical performance in older people with chronic stroke. Design a single-blind randomized controlled trial. Setting Two rehabilitation units in the Wuhan Brain Hospital in China. Participants A total of 78 seniors with chronic stroke. Interventions Low-frequency group (13 Hz), high-frequency group (26 Hz), and zero-frequency group (Standing on the vibration platform with 0 Hz) for 10 sessions of side-alternating WBV training. Main measures The timed-up-and-go test, five-repetition sit-to-stand test, 10-metre walking test, and Berg balance scale were assessed pre- and post-intervention. Results Significant time × group interaction effects in five-repetition sit-to-stand test (p = 0.014) and timed-up-and-go test at self-preferred speed (p = 0.028) were observed. The high-frequency group outperformed the zero-frequency group in both five-repetition sit-to-stand test (p = 0.039) and timed-up-and-go test at self-preferred speed (p = 0.024) after 10-sessions training. The low-frequency group displayed only a significant improvement in five-repetition sit-to-stand test after training (p = 0.028). No significant within- or between-group changes were observed in the Berg balance scale and walking speed (p > 0.05). No significant group-difference were found between low-frequency and high-frequency groups. No adverse events were reported during study. Conclusions Compared with 13 Hz, 26 Hz had no more benefits on balance and physical performance in older people with chronic stroke.