Persistent greening against drying in northeast Asian semiarid grasslands:Asymmetrical responses of direct and legacy effects to intensified drought

Despite experiencing a decadal shift towards drought conditions at the end of the 2Oth century,semiarid grasslands in northeast Asia(NEA)exhibited an evident greening trend from 1982 to 2020.However,the mechanism behind this phenomenon remains unclear.Hence,we analysed the interdecadal changes in vegetation response to drought on the basis of the standardised precipitation evapotranspiration index(SPEI)and Global Inventory Modelling and Mapping Studies LAI4g datasets,with an emphasis on the differences between direct and legacy effects(as measured by resilience),to explore the mechanism of persistent grassland greening.Results revealed that during the post-drought shift period(2000-2020),the sudden decrease in the water content of the intermediate soil layer triggered an intensified vegetation response to drought.Specifically,although direct effects and resilience were amplified,they exhibited asymmetric changes.Resilience was stronger than direct effects,and this difference increased with increasing drought(drought recovery)levels.These combined effects may account for persistent greening against intensified drying in the semiarid grasslands in NEA.Given the projected exacerbation of future droughts,this study holds notable importance for comprehending the long-term change dynamics of dryland ecosystems.

“颈五针”穴位埋线治疗椎动脉型颈椎病疗效及对血流动力学的影响:随机临床试验

Objective:To observe the effect of catgut-embedding therapy at five neck points in the treatment of cervical spondylotic arteriopathy(CSA)and analyze its effects on the hemodynamics of patients with CSA.Methods:Using the computer randomization method,72 patients with CSA were divided into a catgutembedding therapy group(n=36,none dropped out)and a western medication group(n=36,none dropped out).In the catgut-embedding therapy group,the therapy was applied to five neck points,i.e.bilateral Jǐngjiājǐ(颈夹脊)at C5,bilateral Jǐngjiājǐ(颈夹脊)at C6,and Dàzhuī(大椎GV14)once a week.One3-week treatment session was required.In the western medication group,flunarizine hydrochloride 5 mg capsules were administered orally once daily for 3 weeks.Efficacy was assessed before and after 3 weeks treatment using a functional evaluation scale for cervical spondylotic arteriopathy(FS-CSA).Changes in vertebral-basilar arterial hemodynamics,serum nitric oxide(NO)level,and plasma endothelin(ET)level were detected.Results:Efficacy was assessed when the treatment session was completed.The total efficacy rate was significantly higher in the catgut-embedding therapy group(86.1%)than in the western medication group(61.1%;P<0.01).The after treatment FS-CSA score was reduced compared with baseline score in both groups(P<0.05),and the reduction in the catgut-embedding therapy group was superior to that in the Western medication group(P<0.05).Compared with baseline,the flow velocity and pulsatility index of the bilateral vertebral and basilar arteries increased at each period in both groups(P<0.05)except for the left systolic velocity of the vertebral artery after treatment.The increase in the catgut-embedding therapy group was greater than that in the western medication group(P<0.05).After treatment,the serum NO concentration was increased and the plasma ET concentration was reduced compared to baseline in both groups(P<0.05),while the improvements in the catgut-embedding therapy group were superior to those in the western medication group(P<0.05).Conclusion:The clinical efficacy in the catgut-embedding therapy group was superior to that in the western medication group.Catgut-embedding therapy at five neck points may effectively improve psychological and functional conditions,promote vertebral basilar arterial supply,and relieve clinical symptoms in patients with CSA.