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The RNA exosome is a multisubunit 3' to 5' exoribonuclease complex that participates in degradation and processing of cellular RNA. To determine the activities and structure of the eukaryotic exosome, we report the reconstitution of 9-subunit exosomes from yeast and human and reconstitution of 10- and 11-subunit exosomes from yeast. Comparative biochemical(More)
Most small nucleolar RNAs (snoRNAs) guide rRNA nucleotide modifications, some participate in pre-rRNA cleavages, and a few have both functions. These activities involve direct base-pairing of the snoRNA with pre-rRNA using different domains. It is not known if the modification and processing functions occur independently or in a coordinated manner. We(More)
This paper models the messages embedded by spatial least significant bit (LSB) matching as independent noises to the cover image, and reveals that the histogram of the differences between pixel gray values is smoothed by the stego bits despite a large distance between the pixels. Using the characteristic function of difference histogram (DHCF), we prove(More)
We first obtain exponential inequalities for martingales. Let (X k)(1 ≤ k ≤ n) be a sequence of martingale differences relative to a filtration (F k), and set Sn = X1 + ... + Xn. We prove that if for some δ > 0, Q ≥ 1, K > 0 and all k, a.s. E[e δ|X k | Q |F k−1 ] ≤ K, then for some constant c > 0 (depending only on δ, Q and K) and all x > 0, P [|Sn| > nx] ≤(More)
We propose a new image denoising algorithm when the data is contaminated by a Poisson noise. As in the Non-Local Means filter, the proposed algorithm is based on a weighted linear combination of the observed image. But in contract to the latter where the weights are defined by a Gaussian kernel , we propose to choose them in an optimal way. First some "(More)
Let m ≥ 3 be an integer. The so-called m-ary search tree is a discrete time Markov chain which is very popular in theoretical computer science, modelling famous algorithms used in searching and sorting. This random process satisfies a well-known phase transition: when m ≤ 26, the asymptotic behavior of the process is Gaussian, but for m ≥ 27 it is no longer(More)
—Patch-based sparse representation and low-rank approximation for image processing attract much attention in recent years. The minimization of the matrix rank coupled with the Frobenius norm data fidelity can be solved by the hard thresholding filter with principle component analysis (PCA) or singular value decomposition (SVD). Based on this idea, we(More)
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt età la diffusion(More)