A rule-based expert system is described which uses artificial intelligence techniques, and a model of the Interaction between physicians and human consultants, to attempt to satisfy the demands of a user community that Is often reluctant to experiment with computer technology. Experience to date has demonstrated that the program Is efficient, relatively easy to use, and reliable in the domain of bacteremia therapy selection. Future work will involve broadening and evaluating the program's expertise In other areas of infectious disease thPrapy. To that end rules regarding diagnosis and treatment of meningitis have been written and are currently under evaluation.

The general practitioner has accordingly become rare, and today's primary care physicians are beginning to graduate from family practice residencies which recognize that "family doctoring" is a subspecialty in itself. Thus when a patient's problem clearly falls outside the area of the attending physician's expertise, consultations from experts in other subspecialties have become a wellaccepted part of medical practice. Such consultations are acceptable to doctors in pert because they maintain the primary physician's role as ultimate decision maker. The consultation generally involves a dialog between the two physicians, with the expert explaining the basis for his advice and the nonexpert seeking jus-MYCIN Project is located at Stanfcrd University School of Medicine and is zepported by BHSRE Grant No. HS01544. Much of the work described in this report yes undertaken by other project members, notably A.C. Scott and W.J. Clancey, who have devoted much of their time to improvements in the general question-answerer, and R. Davis, who did most of the work on the reasoning status checker and on knowledge acquisition capabilities.

A new predicate calculus deduction system based on production rules is proposed. The system combines several developments in Artificial Intelligence and Automatic Theorem Proving research including the use of domain-specific inference rules and separate mechanisms for forward and backward reasoning. It has a clean separation between the data base, the production rules, and the control system. Goals and subgoals are maintained in an AND/OR tree to represent assertions. The production rules modify these structures until they "connect" in a fashion that proves the goal theorem. Unlike some previous systems that used production rules, ours is not limited to rules In Horn Clause form. Unlike previous PLANNER-like systems, ours can handle the full range of predicate calculus expressions including those with quantified variables, disjunctions and negations.

Because of the recent - echnological advances in computer networks and communications, and because of the cost reduction of computer hardware, there has been a great interest in distributed data bases including some attempts at actual implementations. In this paper, we will first define what we mean by a distributed data base. Then we will give some of the reasons why people are so interested in this new field. After classifying the different types of distributed data bases, we will describe the current areas of research. Finally, we will give an annotated bibliography that lists the most important papers in thi:3 area.

Stanford KSL of Candidate Structures, Based on Comparison between Predicted and Observed Mass Spectra. Mass spec'ral data may be used in structural studies in several ways: 1) For examp:.e, we can create a fragmentation theory based on examination of sets of known structures and their associated mass spectra. All of these operations can, in principle be translated into a set of instructions in a computer program. Some of these programs we have presented in the past. One of these programs uses a combination of a predictor which uses a theory of mass spectrometry to predict the spectra of candidate structures, and an evaluation function which compares the predictions with the observed spectrum of the unknown, assigning a goodnes-of-fit score to each candidate.

Interpretation expected by the referring The technical issues of acquiring this knowledge, physician.

The high resolutioa mass spectra of five 12-membered macrolide aglycones related to methynolide were analyzed with the aid of the Meta-DENDRAL subprogram INTSUM. Metastable defocusing data obtained for several prominent ions in the spectra of two of these mpounds support stepwise cleavage processes subsequent to initial ring opening. Their behavior in the mass spectrometer proved to be highly dependent on the substituents present and their location on the macrocyclic ring. A series of empirical mass spectral fragmentation rules, which were derived from these data, proved useful in differentiating between the mass spectra of closely related isomeric structures. These rules were also useful in the analysis of the fragmentation patterns of several 14-and 16-membered macrolide aglycones. I. INTRODUCTION The non-polyene macrolide antibiotics are a class of medically important compounds characterized by a macrocyclic lactone system containing not more than two conjugated double bonds.

Reprinted with permission from the Journal of the American Chemical Society, Vol.99,No.7,pp.2063-2069. Abstract: A stereoisomerizat ion mode can be defined as a set of symmetry equivalent degenerate rearrangements of a molecular skeleton. The key mathematical constructions in this definition are the double cosets of the skeletal point group in some larger permutation group of identically substituted skeletal sites. S,,L x S.s. is defined which includes all permutations which act on ligand and site labels separately. The generalized stereoisomerization modes are found to be collections of double cosets in this group.

The explanation of...1e was given in terms of

Each computing facility, which we will call a node, includes a process which is in charge of the management of some section of the data base. Each node is connected to the other nodes to allow the sharing of data. We will assume that there is neither shared memory nor global data in the system. Except for this restriction, our model will not specify the interconnection architecture of the network. Au important objective of our studies is in fact the development of measures of computational activities which will lead to evaluation criteria for architectural alternatives [10].