Development of the erv electricity feedback electro-hydraulic appropriate complex flux-control integrated blocks .
erv电反馈电液比例复合流量控制集成阀块的开发研究。
Most erv integrations will be negative or have no effect . The human genome is littered with the decayed remnants of such integrations , often reduced to fragments , or even solitary ltrs . This may explain the origin of retrotransposons .
Once an erv is established in the genome , natural selection will act on it , weeding out viral genes or regulatory sequences that impair survival of the host , ignoring those that have no effect , and positively selecting the rare ones that enhance survival .
Methods : vital capacity ( vc ) and its component expiratory capacity ( erv ) and inspiratory capacity ( ic ) were detected in non-smoking healthy volunteers before and after breathing helium-oxygen mixture and the changes were compared .
