The Exosome Subunit Rrp44 Plays a Direct Role in RNA Substrate Recognition

The exosome plays key roles in RNA maturation and surveillance, but it is unclear how target RNAs are identified. We report the functional characterization of the yeast exosome component Rrp44, a member of the RNase II family. Recombinant Rrp44 and the purified TRAMP polyadenylation complex each specifically recognized tRNAiMet lacking a single m1A58 modification, even in the presence of a large excess of total tRNA. This tRNA is otherwise mature and functional in translation in vivo but is presumably subtly misfolded. Complete degradation of the hypomodified tRNA required both Rrp44 and the poly(A) polymerase activity of TRAMP. The intact exosome lacking only the catalytic activity of Rrp44 failed to degrade tRNAiMet, showing this to be a specific Rrp44 substrate. Recognition of hypomodified tRNAiMet by Rrp44 is genetically separable from its catalytic activity on other substrates, with the mutations mapping to distinct regions of the protein

The rank of the semigroup of transformations stabilising a partition of a finite set

Let $\mathcal{P}$ be a partition of a finite set $X$. We say that a full transformation $f:X\to X$ preserves (or stabilizes) the partition $\mathcal{P}$ if for all $P\in \mathcal{P}$ there exists $Q\in \mathcal{P}$ such that $Pf\subseteq Q$. Let $T(X,\mathcal{P})$ denote the semigroup of all full transformations of $X$ that preserve the partition $\mathcal{P}$. In 2005 Huisheng found an upper bound for the minimum size of the generating sets of $T(X,\mathcal{P})$, when $\mathcal{P}$ is a partition in which all of its parts have the same size. In addition, Huisheng conjectured that his bound was exact. In 2009 the first and last authors used representation theory to completely solve Hisheng's conjecture. The goal of this paper is to solve the much more complex problem of finding the minimum size of the generating sets of $T(X,\mathcal{P})$, when $\mathcal{P}$ is an arbitrary partition. Again we use representation theory to find the minimum number of elements needed to generate the wreath product of finitely many symmetric groups, and then use this result to solve the problem. The paper ends with a number of problems for experts in group and semigroup theories

Using distributional similarity to organise biomedical terminology

We investigate an application of distributional similarity techniques to the problem of structural organisation of biomedical terminology. Our application domain is the relatively small GENIA corpus. Using terms that have been accurately marked-up by hand within the corpus, we consider the problem of automatically determining semantic proximity. Terminological units are dened for our purposes as normalised classes of individual terms. Syntactic analysis of the corpus data is carried out using the Pro3Gres parser and provides the data required to calculate distributional similarity using a variety of dierent measures. Evaluation is performed against a hand-crafted gold standard for this domain in the form of the GENIA ontology. We show that distributional similarity can be used to predict semantic type with a good degree of accuracy

Defeating the Terminator: How Remastered Albums May Help Record Companies Avoid Copyright Termination

Starting in 2013, copyright owners can begin terminating copyright grants made thirty-five years earlier. In the music industry, this termination right could harm the profits of record companies, which rely on valuable older recordings to drive profits. But all is not lost for these record companies, as termination is not guaranteed. Congress excluded certain types of work from termination, including derivative works. After outlining the standards courts use to determine what constitutes a derivative work and how remastered albums are made, this Note analyzes whether remastered albums will be considered derivative works and thus not subject to termination. The Note concludes that, generally, remastered albums should be considered derivative works. Finally, the Note argues that allowing record companies to continue to utilize these remastered recordings furthers the legislative purposes of both the termination provision and the derivative works exception

Mass-sheet degeneracy: Fundamental limit on the cluster mass reconstruction from statistical (weak) lensing

Weak gravitational lensing is considered to be one of the most powerful tools to study the mass and the mass distribution of galaxy clusters. However, weak lensing mass reconstructions are plagued by the so-called mass-sheet degeneracy--the surface mass density \kappa of the cluster can be determined only up to a degeneracy transformation \kappa \to \kappa' = \lambda \kappa + (1 -\lambda), where \lambda is an arbitrary constant. This transformation fundamentally limits the accuracy of cluster mass determinations if no further assumptions are made. We describe here a method to break the mass-sheet degeneracy in weak lensing mass maps using distortion and redshift information of background galaxies and illustrate this by two simple toy models. Compared to other techniques proposed in the past, it does not rely on any assumptions on cluster potential; it can be easily applied to non-parametric mass-reconstructions and no assumptions on boundary conditions have to be made. In addition it does not make use of weakly constrained information (such as the source number counts, used in the magnification effect). Our simulations show that we are effectively able to break the mass-sheet degeneracy for supercritical lenses, but that for undercritical lenses the mass-sheet degeneracy is very difficult to be broken, even under idealised conditions.Comment: Accepted for publication in A&

\u3cem\u3eTherasense\u3c/em\u3e-less: How the Federal Circuit Let Policy Overtake Precedent in \u3cem\u3eTherasense, Inc. v. Becton, Dickinson & Co.\u3c/em\u3e

On May 25, 2011, in Therasense, Inc. v. Becton, Dickinson & Co., the en banc U.S. Court of Appeals for the Federal Circuit fundamentally restructured the patent law doctrine of inequitable conduct. The court did so by holding that both intent and materiality are required for successfully claiming the defense, and that materiality must be proven by a but-for test, thereby limiting the scope of conduct covered by the doctrine. Although in making this change the court may have helped to curb the over usage of inequitable conduct, it did so by contradicting Supreme Court precedent. Thus, this Comment argues that the Therasense court overstepped its bounds and, in its attempt to limit the doctrine, may have unduly narrowed this equitable defense