Translation of mRNA injected into Xenopus oocytes is specifically inhibited by antisense RNA.

The bacteriophage SP6 promoter and RNA polymerase were used to synthesize sense and antisense RNAs coding for the enzymes thymidine kinase (TK) and chloramphenicol acetyl transferase (CAT). Injection of antisense CAT RNA into frog oocytes inhibited expression of sense CAT mRNA. Similarly, antisense TK RNA inhibited expression of sense TK mRNA. Antisense RNAs were stable in oocytes and had no detectable effect on either the expression of endogenous proteins or on the expression of nonhomologous RNA transcripts. CAT activity expressed from a plasmid transcribed in the oocyte nucleus was also inhibited by antisense RNA injected into the oocyte cytoplasm. The data suggest that antisense RNA will be useful in identifying the function of specific mRNA sequences during early development of the frog

Photon-Photon Collisions with SuperChic

The SuperChic Monte Carlo generator provides a common platform for QCD-mediated, photoproduction and photon-induced Central Exclusive Production (CEP), with a fully differential treatment of soft survival effects. In these proceedings we summarise the processes generated, before discussing in more detail those due to photon-photon collisions, paying special attention to the correct treatment of the survival factor. We briefly consider the light-by-light scattering process as an example, before discussing planned extensions and refinements for the generator.Comment: 6 pages, 2 figures. Submitted to proceedings of the PHOTON 2017 conferenc

Making logic programs reactive

Logic programming languages based on linear logic have been of recent interest, particularly as such languages provide a logical basis for programs which execute within a dynamic environment. Most of these languages are implemented using standard resolution or backward-chaining techniques. However, there are applications for which the use of forward-chaining techniques within a dynamic environment are appropriate, such as genetic algorithms, active databases and agent-based systems, and for which it is difficult or impossible to specify an appropriate goal in advance. In this paper we discuss the foundations for a forward-chaining approach (or in logic programming parlance, a bottom-up approach) to the execution of linear logic programs, which thus provides forward-chaining within a dynamic environment. In this way it is possible not only to execute programs in a forward-chaining manner, but also to combine forward- and backward-chaining execution. We describe and discuss the appropriate inference rules for such a system, the formal results about such rules, the role of search strategies, and applications

Effective Heisenberg model and exchange interaction for strongly correlated systems

We consider the extended Hubbard model and introduce a corresponding Heisenberg-like problem written in terms of spin operators. The derived formalism is reminiscent of Anderson's idea of the effective exchange interaction and takes into account nonlocal correlation effects. The results for the exchange interaction and magnetic susceptibility are expressed in terms of single-particle quantities, which can be obtained efficiently in realistic calculations of multiband systems. In the strongly spin-polarized limit, when the local magnetic moment is well-defined, the exchange interaction reduces to a standard expression of the density functional theory that has been successfully used in practical calculations of magnetic properties of real materials.Comment: Accepted to Physical Review Letter

Acoustic characterization of crack damage evolution in sandstone deformed under conventional and true triaxial loading

We thank the Associate Editor, Michelle Cooke, and the reviewers, Ze'ev Reches and Yves Guéguen, for useful comments which helped to improve the manuscript. We thank J.G. Van Munster for providing access to the true triaxial apparatus at KSEPL and for technical support during the experimental program. We thank R. Pricci for assistance with technical drawings of the apparatus. This work was partly funded by NERC award NE/N002938/1 and by a NERC Doctoral Studentship, which we gratefully acknowledge. Supporting data are included in a supporting information file; any additional data may be obtained from J.B. (e-mail: [email protected]).Peer reviewedPublisher PD

Simplifying the development of intelligent agents

Intelligent agents is a powerful Artificial Intelligence technology which shows considerable promise as a new paradigm for mainstream software development. However, despite their promise, intelligent agents are still scarce in the market place. A key reason for this is that developing intelligent agent software requires significant training and skill: a typical developer or undergraduate struggles to develop good agent systems using the Belief Desire Intention (BDI) model (or similar models). This paper identifies the concept set which we have found to be important in developing intelligent agent systems and the relationships between these concepts. This concept set was developed with the intention of being clearer, simpler, and easier to use than current approaches.We also describe briefly a (very simplified) example from one of the projects we have worked on (RoboRescue), illustrating the way in which these concepts are important in designing and developing intelligent software agents

Experiences in teaching computing theory via aspects of problem-based learning

Computing Theory is a compulsory subject that many computer science students find difficult, and for which there is a wide range of abilities and backgrounds amongst students. In this paper we describe the evolution of this subject at our university over the past decade, which has resulted in a much more student-centred approach to learning. This has not only enhanced the learning experience of the students but also has simplified the development of teaching modes and resources involving on-line replacements for lectures