Concerted utility review of VVER-440 safety research needs (VERSAFE)

There are twelve operating VVER-440/213 reactors in the Czech Republic, Hungary and Slovakia. The plant owners have carried out extensive safety enhancement programmes, which have included measures to improve prevention, mitigation and control of design basis accidents. Recently, there have been a number of projects to study the Severe Accident Management aspects of these plants. The plant owners have also initiated Plant Life Management programmes. The objective of the VERSAFE Concerted Action is to create a network of the VVER-440/213 plant owners and operators, which aims at definition of the further research needs of severe accidents and plant ageing from the utilities’ viewpoint. The starting point is to formulate a general approach to severe accident management and plant life management and then proceed to define the needs for the additional information expected from the safety research. The role of national research institutes and organisations of the partner countries is of crucial importance in performing such research and, thus, creating and maintaining the expertise on the national level. The successful completion of the project will assist in establishing well-defined research projects that are oriented to the needs of the end-users and provide information that can be used to facilitate and support the negotiations of the EU applicant countries operating VVER-440 reactors.     

Broadening the Scope of Hypermedia Principles

Hypermedia systems have been implemented for such a wide range of applications that one must wonder whether their principles should not be included among the building blocks of computer environments themselves. In this paper, we argue that this would indeed be desirable and present a model on which such extension could be based.

After a brief review of hypermedia principles and the terminology used in this paper, we give examples of several computer applications in which hypermedia already are or could advantageously be used. We then suggest that most computer applications would greatly benefit if hypermedia were extended from isolated applications to a system-wide facility and that this could substantially simplify implementation of new hypermedia applications. This claim is then generalized and it is shown that extending hypermedia concepts to the organization of the computer environment itself --- the file system --- and to the user interface would make computer environments more flexible and easier to use.

We then list the main characteristics of such a ‘hyperenvironment’ and conclude the paper with an outline of its implementation model and an example.     

A framework for computing extrasentential references

We are concerned with developing a computational method for selecting possible antecedents of referring expressions over sentence boundaries. Our stratified model which uses a Λ-categorial language for meaning representation incorporates valuable features of Fregean-type semantics (a la Lewis, Montague, Partee, and others) along with features of situation semantics developed by Barwise and Perry. We consider a series of selected two-sentence stories which we use to illustrate referential interdependencies between sentences. We explain the conditions under which such dependencies arise, explain the conditions under which various translations can be performed, and formalize a set of rules which specify how to compute the reference. We restrict our discussion to two-sentence stories to avoid most of the problems inherent in where to look for the reference, that is, how to determine the proper antecedent. We restrict our considerations in this paper to situations where a reference, if it can be computed at all, has a unique antecedent. Thus we consider examples such as John wants to catch a fish. He (John) wants to eat it. and John interviewed a man. The man killed him (John). We then summarize the transformation which encompasses these rules and relate it to the stratified model. We discuss three aspects of this transformation that merit special attention from the computational viewpoint and summarize the contributions we have made. We also discuss the computational characteristics of the stratified model in general and present our ideas for a computer realization; there is no implementation of the _t"ratified model at this time.     

Establishment and characterization of a megakaryoblast cell line with amplification of MLL

A new cell line with megakaryoblastic features, designated UoC-M1, was established from the malignant cells of a 68-year-old patient with acute myeloid leukemia. The patient's leukemic cells reacted with alpha-naphthyl acetate esterase and acid phosphatase and expressed CD7, CD24, CD34, CD38, CD45, HLA-DR and CD61. Cytogenetic analysis of the patient's malignant cells (and of the UoC-M1 cells) showed a human, male hypodiploid karyotype with many chromosome rearrangements and marker chromosomes. Spectral karyotyping (SKY) analysis complemented the G-banded karyotyping and clarified several chromosomal translocations and identified the marker chromosomes. Fluorescence in situ hybridization (FISH) and SKY analysis demonstrated that one marker chromosome contained three segments of chromosome 9 interspersed with three segments of chromosome 11, as well as a portion of chromosome 19. FISH analysis with a probe for MLL revealed that the UoC-M1 cells contained four copies of the MLL gene. Southern blot analysis determined that the MLL gene had a germline profile while Northern and Western analyses showed that the MLL mRNAs and protein were of the appropriate sizes. This is the first report of amplification of the MLL gene which may be an additional mechanism of leukemogenesis or disease progression.     

Modeling correlation in software recovery blocks

The authors examine the problem of accurately modeling the software fault-tolerance technique based on recovery blocks. Analysis of some systems have investigated the correlation between software modules, which may be due to a portion of the functional specification that is common to all software modules, or to the inherent hardness of some problems. Three types of dependence which can be captured using measurements are considered. These are correlation between software modules for a single input, correlation between successive acceptance tests on correct module outputs and incorrect module outputs, and correlation between subsequent inputs. The authors' technique is quite general and can be applied to other types of correlation. In accounting for dependence, they use the intensity distribution introduced by D.E. Eckhardt and L.D. Lee (1985). A method of generating the intensity distribution that is based on the pairwise correlation between modules is discussed. This method is contrasted with the assumption of independent modules as well as the use of the beta-binomial density introduced by V.F. Nicola and A. Goyai (1990). The effects of dependencies were studied using a Stochastic Reward Network (SRN) that incorporates all of the above dependencies and a modeling tool called Stochastic Petri Net Package (SPNP)     

Biosynthesis of Colabomycin E,a New Manumycin‐Family Metabolite,Involves an Unusual Chain‐Length Factor

Colabomycin E is a new member of the manumycin‐type metabolites produced by the strain Streptomyces aureus SOK1/5‐04 and identified by genetic screening from a library of streptomycete strains. The structures of colabomycin E and accompanying congeners were resolved. The entire biosynthetic gene cluster was cloned and expressed in Streptomyces lividans. Bioinformatic analysis and mutagenic studies identified components of the biosynthetic pathway that are involved in the formation of both polyketide chains. Recombinant polyketide synthases (PKSs) assembled from the components of colabomycin E and asukamycin biosynthetic routes catalyzing the biosynthesis of “lower” carbon chains were constructed and expressed in S. aureus SOK1/5‐04 ΔcolC11–14 deletion mutant. Analysis of the metabolites produced by recombinant strains provided evidence that in both biosynthetic pathways the length of the lower carbon chain is controlled by an unusual chain‐length factor supporting biosynthesis either of a triketide in asukamycin or of a tetraketide in colabomycin E. Biological activity assays indicated that colabomycin E significantly inhibited IL‐1β release from THP‐1 cells and might thus potentially act as an anti‐inflammatory agent.     

Josef,the robot

Computers cannot be properly understood without at least an elementary exposure to programming. Many teachers would reject this proposal on the grounds that for many people programming is too difficult and uninteresting. This objection is probably correct if we imply that programming should be introduced in a general purpose programming language. Its validity becomes questionable if the vehicle is a special programming language which puts the student into a natural environment, familiar to every ordinary person.The LOGO system is a well known example of such a natural environment. This article presents a related language called Josef which is used to program a robot moving on the map of a computer terminal. The distinguishing features of Josef are: (a) Extensibility of built-in vocabulary: (b) Possibility of fully top-down approach to the solution of large problems; (c) Similarity to general purpose languages in terms of concepts available in the language and the syntax used to express them: (d) Ability to work on ordinary computer terminals.The larger part of the article attempts to present the general philosophy of the language on a few programming examples of medium complexity.