C/D box small nucleolar RNAs (snoRNAs) guide site-specific 2'-O-methylation of RNAs. Nearly all C/D box snoRNAs with known targets are involved in rRNA modification. In vertebrates, snoRNAs are encoded in introns of various genes and their processing is coupled with splicing of host gene pre-mRNA. Here, the genes encoding C/D box snoRNAs that guide 2'-O-methylation of rRNA were identified and a...

In eukaryotes, many Box C/D small nucleolar RNAs base pair with ribosomal RNA through short complementary guide sequences, thereby marking up to 100 individual nucleotides of ribosomal RNA for 2'-O-methylation. Function of the eukaryotic Box C/D RNAs depends upon interaction with at least six known proteins. Box C/D RNAs are not known to exist in Bacteria but were recently identified in Archaea...

We give the first nontrivial upper and lower bounds on the maximum volume of an empty axisparallel box inside an axis-parallel unit hypercube in R containing n points. For a fixed d, we show that the maximum volume is of the order Θ( 1 n ). We then use the fact that the maximum volume is Ω( 1 n ) in our design of the first efficient (1 − ε)-approximation algorithm for the following problem: Giv...

Box C/D RNAs are small, noncoding RNAs that function in RNA modification in eukaryotes and archaea. Here, we report that box C/D RNAs exist in the rare biological form of RNA circles in the hyperthermophilic archaeon Pyrococcus furiosus. Northern analysis of box C/D RNAs reveals two prominent RNA species of different electrophoretic mobilities in total P. furiosus RNA preparations. Together, th...

A method for fault detection is proposed using nonlinear black-box models, such as polynomial regression and neural networks. Compared to existing methods, this proposed method has the advantage of not requiring model training under all the possible faulty modes of the monitored system. Partial physical knowledge , if available, can be combined with the nonlinear black-box model to perform faul...

An `-sparse (multivariate) polynomial is a polynomial containing at most `-monomials in its explicit description. We assume that a polynomial is implicitly represented as a black-box: on an input query from the domain, the black-box replies with the evaluation of the polynomial at that input. We provide an efficient, randomized algorithm, that can decide whether a polynomial f : Fq → Fq given a...

The box C/D small nucleolar RNPs (snoRNPs) are essential for the processing and modification of rRNA. The core box C/D proteins are restructured during human U3 box C/D snoRNP biogenesis; however, the molecular basis of this is unclear. Here we show that the U8 snoRNP is also restructured, suggesting that this may occur with all box C/D snoRNPs. We have characterized four novel human biogenesis...

A condensed-mass advection based model for the simulation of liquid polar stratospheric clouds D. Lowe, A. R. MacKenzie, N. Nikiforakis, and J. Kettleborough Lancaster University, United Kingdom DAMTP, Cambridge University, United Kingdom Rutherford Appleton Laboratory, United Kingdom Received: 22 March 2002 – Accepted: 15 May 2002 – Published: 12 June 2002 Correspondence to: D. Lowe (d.lowe@la...