Progress report on a new search for free e/3 quarks in the cores of 10(15) - 10(16) eV air showers

The Leeds 3 sq m Wilson cloud chamber is being used in a new search for free e/3 quarks close to the axes of 10 to the 15th power - 10 to the 16th power eV air showers. A ratio trigger circuit is used to detect the incidence of air shower cores; the position of the shower center and the axis direction are determined from photographs of current-limited spark chambers. It is thus possible, for the first time, to know where we have looked for quarks in air showers and to select for scanning only those cloud chamber photographs where we have good evidence that the shower axis was close to the chamber. 250 g/sq cm of lead/concrete absorber above the cloud chamber serve to reduce particle densities and make a quark search possible very close to the shower axes. The current status of the search is given

Details of a scientific approach to information systems, Courant Symp. in Data Base Systems

are the optimal strategy for the usage considered. If it is assumed now that all q s = 0 (i.e. there is no querying to the IPS) then it is clear that no indexing path is profitable. Rule 4 If only queries and no maintenance are performed then all the candidate indexing paths are included in the optimal strategy whereas if maintenance only is done, no indexing path appears in the IPS. Conclusions A file designer who cannot determine the effects of each alternative decision is bound to make subjective or intuitive design judgements instead of objective ones. The properties and rules stated (a) provide the means to improve the performance of IPS by expanding the current spectrum of alternative indexing paths examined prior to making any implementation decision, and (b) provide for increased confidence in the decision made. In Book review A Programming Metholodology in Compiler Construction Part I: Concepts by J. Lewi, K. De Vlaminck, J. Huens and M. Huybrechts, 1979; 308 pages. (North-Holland, $41.50) In the late 1950s the task of compiler construction was considered a major undertaking. The first FORTRAN compiler, for example, took 18 man-years to implement (Backus et al, 1957). Now, in the late 1970s, such a task is considered a reasonable computer science student project. The factors that have led to this over the last twenty years are (a) the comprehension of the organisation and modular design of the compilation process, (b) the development of systematic techniques for handling the majority of the important tasks that occur during compilation and (c) the construction of software tools that assist in the implementation of compilers and compiler components. Implicit in all these three developments is the closing of the gap between theory and practice. This book is the first part of a twopart description of an environment utilising a completely closed gap. Part I introduces the basic theoretical models whilst part 2 will consider the more practical aspects of the engineering of the environment (namely the language implementation laboratory [LILA] [transducer] programs from the associated syntax. As such, each section is the logical progression of the previous and the methodology used in each section is a reflection of the methodology of the previous section. Hence the book is structurally pleasing and easy to read. In conclusion, the book is ideally suited to the software engineer who is actively involved in the application of language theory to compiler construction (or the construction of any systems softwar

Expert Leadership and Hidden Inequalities in Community Projets

This chapter explores the development of a mid-range theory that can be used in organisations when considering how to engage multiple stakeholders in a project that requires expert input. The case study presented here is concerned with a ground-breaking approach to integrate heritage, culture and social benefit through the medium of archaeology and heritage. The findings indicated that the ‘expert’ as a leader of the project created hidden inequalities in the team, preventing the longer-term social outcomes of the project from materialising. A Realist Evaluation (Pawson and Tilley, 1997a) protocol was developed which created an ‘intervention’, permitting the non-linear complex interactions between multiple groups and multiple stakeholders to be observed and evaluated. This allowed for the political, strategic, organisational, operational and individual perspectives to be addressed making it a suited evaluative approach to this type of multiple stakeholder project