The 'central dogma 'of molecular biology indicated that the direction of the genetic information flow is from DNA - RNA - protein. However, up to now, the central dogma has not obtained a sufficient theoretica...The 'central dogma 'of molecular biology indicated that the direction of the genetic information flow is from DNA - RNA - protein. However, up to now, the central dogma has not obtained a sufficient theoretical support from cybernetics and information theory. In addition, some special cases in biology, such as, although the scrapie prion is irreversibly inactivated by alkali, five procedures with more specificity for modifying nucleic acids failed to cause inactivation and when a resting cell is activated by some factors and division occurs, protein synthesis has begun before DNA synthesis etc., are also very difficult to explain clearly by the central dogma. A broad outline of a mechanism for reverse translation can easily be 'designed', based on the normal translation process, and this serves both to prove that there is no fundamental theoretical reason for the central dogma, and to illustrate why the redundancy of genetic code is not a problem.This paper, based on some previous research work of authors, from the view of cybernetics, information theory and theoretical biology, explored the possibility of protein as a genetic information carrier, the probable pairing ways between ammo acids-codons, and the direction of genetic information flows etc., at theory, by comparing and analyzing theoretically the characteristics of information carriers existing in DNA and protein. The authors inferred that perhaps protein may join the informational transferring as a genetic information carrier; the direction of genetic information flows, besides the way described by the central dogma, seem also to have another type, that is, genetic information flowing from protein - DNA (RNA) - protein, which also includes the genetic information flow in the central dogma. Undoubtedly, the research on problems about the position and roles of protein during the genetic information transferring will have an important effect on the investigation and development of molecular biology, molecular genetics and gene engineering.展开更多
针对舰载机甲板路径规划问题,在Informed-RRT^(*)(informed rapidly-exploring random tree)的椭圆采样基础上,提出使用正态分布方式采样的IN-RRT^(*)(informed normal-RRT^(*))算法。首先,针对舰载机与运动场景建模,定义舰载机运动约...针对舰载机甲板路径规划问题,在Informed-RRT^(*)(informed rapidly-exploring random tree)的椭圆采样基础上,提出使用正态分布方式采样的IN-RRT^(*)(informed normal-RRT^(*))算法。首先,针对舰载机与运动场景建模,定义舰载机运动约束和避障策略;其次,将正态分布采样策略与椭圆采样相结合,获取优质高效采样点;引入人工势场法,自适应调节随机树的搜索步长值;使用向心Catmull-Rom样条插值法对路径进行平滑优化处理;提出针对动态障碍改进的动态窗口法,实现局部动态避障。最后,运用甲板平面环境实验检验算法性能。结果表明,IN-RRT^(*)算法能显著优化搜索时间和搜索路径质量,可应对动态场景规划出合理可行的平滑路径。展开更多
文摘The 'central dogma 'of molecular biology indicated that the direction of the genetic information flow is from DNA - RNA - protein. However, up to now, the central dogma has not obtained a sufficient theoretical support from cybernetics and information theory. In addition, some special cases in biology, such as, although the scrapie prion is irreversibly inactivated by alkali, five procedures with more specificity for modifying nucleic acids failed to cause inactivation and when a resting cell is activated by some factors and division occurs, protein synthesis has begun before DNA synthesis etc., are also very difficult to explain clearly by the central dogma. A broad outline of a mechanism for reverse translation can easily be 'designed', based on the normal translation process, and this serves both to prove that there is no fundamental theoretical reason for the central dogma, and to illustrate why the redundancy of genetic code is not a problem.This paper, based on some previous research work of authors, from the view of cybernetics, information theory and theoretical biology, explored the possibility of protein as a genetic information carrier, the probable pairing ways between ammo acids-codons, and the direction of genetic information flows etc., at theory, by comparing and analyzing theoretically the characteristics of information carriers existing in DNA and protein. The authors inferred that perhaps protein may join the informational transferring as a genetic information carrier; the direction of genetic information flows, besides the way described by the central dogma, seem also to have another type, that is, genetic information flowing from protein - DNA (RNA) - protein, which also includes the genetic information flow in the central dogma. Undoubtedly, the research on problems about the position and roles of protein during the genetic information transferring will have an important effect on the investigation and development of molecular biology, molecular genetics and gene engineering.
文摘针对舰载机甲板路径规划问题,在Informed-RRT^(*)(informed rapidly-exploring random tree)的椭圆采样基础上,提出使用正态分布方式采样的IN-RRT^(*)(informed normal-RRT^(*))算法。首先,针对舰载机与运动场景建模,定义舰载机运动约束和避障策略;其次,将正态分布采样策略与椭圆采样相结合,获取优质高效采样点;引入人工势场法,自适应调节随机树的搜索步长值;使用向心Catmull-Rom样条插值法对路径进行平滑优化处理;提出针对动态障碍改进的动态窗口法,实现局部动态避障。最后,运用甲板平面环境实验检验算法性能。结果表明,IN-RRT^(*)算法能显著优化搜索时间和搜索路径质量,可应对动态场景规划出合理可行的平滑路径。
