A third superchron during the Early Paleozoic

Research on geomagnetic reversal chronology has established the existence of two superchrons, one during the Cretaceous and the other (Kiaman) during the Late Paleozoic.Over the past few years, we have performed several magnetostratigraphic studies on Early Paleozoic (Cambrian and Ordovician) sedimentary sequences from Siberia. Our results show high magnetic reversal frequencies during the Middle Cambrian. In contrast, several records show the occurrence of a -20 Myr long reversed polarity interval in the Lower and Middle Ordovician, suggesting the presence of a third superchron. We propose to give the name of “Moyero” to this new superchron; this name is attributed to the Siberian section which first yielded a complete record of this reversed polarity interval.

语词的语义——功能变异以及对高级EFL学生的词汇教学

本文旨在探讨英语词汇系统构造的一个侧面:语义——功能变异。这可以理解为一种派生性过程,类似于词类转换法,但是它出现在词类的次类层次。通过这种方法,一个词汇单位转属一新的语义——功能次类,而在保留词义成分的同时获得新范畴的语义特征。由此产生的一个词位的语义——功能变体在话语中则起不同的作用。本文分节讨论了这种变异的不同层次。由于语义——功能变异在很多情况下被词典编纂者和语法学家们所忽略。