A number of studies show that premarital cohabitation is associated with an increased risk of subsequent marital dissolution. Some argue that this is a consequence of selection effects and that once these are controlled for premarital cohabitation has no effect on dissolution. We examine the effect of premarital cohabitation on subsequent marital dissolution by using rich retrospective life-his...

2014 The present paper discusses an experiment, using a Middleton sputter ion source, where a sensitive search was made for 14Nions in the presence of an intense carbon beam. It was found that negative nitrogen ions, capable of withstanding acceleration fields of 1.5 MV/m, were not produced in detectable intensities. The paper also points out some design requirements of tandem facilities that m...

During plant epidermal development, many cell types are generated fromprotodermal cells, a process requiringcomplex co-ordinationof cell division, growth, endoreduplication and the acquisition of differentiated cellular morphologies. Herewe show that theArabidopsis phytocalpain DEFECTIVE KERNEL 1 (DEK1) promotes the differentiated epidermal state. Plants with reduced DEK1 activity produce cotyl...

The proposed linear electron-positron collider TESLA is based on 1.3 GHz superconducting niobium cavities for particle acceleration. For a center-of-mass energy of 500 GeV an accelerating field of 23.4 MV/m is required which is reliably achieved with a niobium surface preparation by chemical etching. An upgrade of the collider to 800 GeV requires an improved cavity preparation technique. In thi...