RNase P preparations from Escherichia coli can be separated into RNA and protein by chromatography, in buffers containing 7 M urea, on Sephadex G-200, DEAE-Sephadex, or CM-Sephadex columns. Neither RNA nor protein components alone exhibits any RNase activity. RNase P activity can be reconstituted by mixing separated RNA and protein components in buffer containing 7M urea followed by dialysis of...

Independently folded domains in RNAs frequently adopt identical tertiary structures regardless of whether they are in isolation or are part of larger RNA molecules. This is exemplified by the P15 domain in the RNA subunit (RPR) of the universally conserved endoribonuclease P, which is involved in the processing of tRNA precursors. One of its domains, encompassing the P15 loop, binds to the 3'-e...

Recent two dimensional nuclear magnetic resonance (NMR) techniques access exchange in pore structures through surface relaxation and diffusion based relaxation [1-4]. This research applies these techniques to measure pore changes due to biofilm growth and the impact this growth has on diffusion transport. The porous media used in this study are model beadpacks constructed from borosilicate glas...

1 The author wishes to express his indebtedness to the Carnegie Corporation of New York for a research grant in support of our development of multiple factor analysis and its application to the study of primary mental abilities. 2 L. L. Thurstone, "Theory of Multiple Factors," 1932, pp. 17-27, Edward Brothers, Ann Arbor, Mich. 8 Harold Hotelling, "Analysis of a complex of statistical variables ...

We analyse a newspaper market where media …rms compete for advertising as well as for readership. Firms …rst choose the political position of their newspaper, then set cover prices and advertising tari¤s. We build on the duopoly work in two-sided markets of Gabszewicz, Laussel, and Sonnac (2001, 2002) who show that advertising …nancing can lead to minimum political di¤erentiation. We extend the...

We study two types of targeting in this paper, exogenous targeting and endogenous targeting. By exogenous targeting we mean targeting by product preferences: advertising levels and prices geared to specific consumer preferences. Exogenous targeting presumes observability of consumer preferences (or of factors correlated with them). This is the sort of targeting that is much in the news in conte...