...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Acta crystallographica.Section D. Biological crystallography >To B or not to B: A question of resolution?
【24h】

To B or not to B: A question of resolution?

机译：B还是B:解决的问题吗?

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In choosing and refining any crystallographic structural model, there is tension between the desire to extract the most detailed information possible and the necessity to describe no more than what is justified by the observed data. A more complex model is not necessarily a better model. Thus, it is important to validate the choice of parameters as well as validating their refined values. One recurring task is to choose the best model for describing the displacement of each atom about its mean position. At atomic resolution one has the option of devoting six model parameters (a thermal ellipsoid) to describe the displacement of each atom. At medium resolution one typically devotes at most one model parameter per atom to describe the same thing (a B factor). At very low resolution one cannot justify the use of even one parameter per atom. Furthermore, this aspect of the structure may be described better by an explicit model of bulk displacements, the most common of which is the translation/libration/screw (TLS) formalism, rather than by assigning some number of para-meters to each atom individually. One can sidestep this choice between atomic displacement parameters and TLS descriptions by including both treatments in the same model, but this is not always statistically justifiable. The choice of which treatment is best for a particular structure refinement at a particular resolution can be guided by general considerations of the ratio of model parameters to the number of observations and by specific statistics such as the Hamilton R - factor ratio test.
机译：在选择任何晶体和精炼结构模型,有之间的紧张关系想提取最详细的信息可能和必要的描述比由观测数据是合理的。更复杂的模型不一定是更好的模型。参数的选择以及验证他们精制的价值观。最好的模型来描述位移每个原子的平均位置。解决一个投入六的选项模型参数(热椭球)描述每个原子的位移。分辨率通常投入最多每个原子模型参数来描述是一样的件事(B因子)。不能证明甚至每一个参数的使用原子。可以更好地描述一个显式模型的大部分流离失所,最常见的是翻译/振动/螺丝(TLS)形式主义,而不是通过分配一些数量para-meters单独每个原子。避开这个原子位移之间的选择包括参数和TLS的描述治疗在同一模型中,但这不是总统计上合理的。哪种治疗最适合一个特定的吗结构优化在一个特定的决议可以遵循的一般注意事项模型参数的数量的比例观察和特定的统计等汉密尔顿R -因子比值判别法。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号