A specification language for planning and fault recovery in manufacturing systems

This paper presents the syntax and semantics of a component-oriented rule-based language for specifying the formal models of manufacturing systems. A model captures the state of a component of the system in a set of first-order logic predicates, and it captures the semantics of the operations performed by this component in a set of rules that determine the preconditions and postconditions of an operation. The models are then used to plan the sequence of operations of each class of jobs to be manufactured by these systems. A plan-oriented fault detection and correction strategy is proposed. This strategy can automatically handle any combination of faults that may occur when monitoring the operations of manufacturing systems. A fault-tree is consulted prior to executing the scheduled operations of a plan, and the faults that affect the execution of these operations are handled subsequently. Resuming the original cyclic schedule is attempted, whenever feasible. As a proof of concept, a prototype implementation of both the main constructs of the component-oriented rule-based language and the planning and fault-recovery algorithms presented in this paper have been completed. This prototype is implemented on a Unix-based system in the Ada programming language. The specification of a manufacturing system is first expressed in the proposed language. These statements are then translated into Ada code. This code is next compiled by a Verdix Ada compiler and is executed in order to create and populate the model data structure of the system. A detailed plan of execution and a set of fault-recovery plans may then be derived for a job to be manufactured on this system.     

Nuclear behavior in vegetative hyphae of Trichophyton terrestre

Vegetative nuclear division inTrichophyton terrestre Durie & Frey was studied utilizing the aceto-orcein squash technique. Nuclear division included: no directional preference to the hyphal axis; longitudinal splitting of daughter nuclei; and a haploid chromosome count of four. Interphase and prophase nuclei were morphologically similar to those of higher plants, however, various degrees of chromosome condensation and elongation were noted. Spindle pole bodies were prominent at metaphase.     

Regional mapping of the gene for autosomal dominant spinocerebellar ataxia (SCA1) by localizing the closely linked D6S89 locus to 6p24.2----p23.05.

The locus for one subtype of autosomal dominant spinocerebellar ataxias (SCA1) is closely linked (within 1-2 cM) to D6S89, which contains a highly polymorphic dinucleotide repeat sequence. D6S89 has been mapped previously to 6p24----p21.3, between the HLA and F13A1 loci. Mutant cell lines were used to correlate the absence or presence of D6S89 with cytogenetically detectable interstitial 6p deletions. The results allowed us to map D6S89 to the 6p24.2----p23.05 region. The close linkage of SCA1 to D6S89 indicates that this locus is most likely located in the 6p24----p23 segment.     

The antifungal activity of normal and host-compromised saliva on spaceflight fungal phenotypes

Phenotypic variants of parent strains ofChaetomium globosum, Trichophyton terrestre, Rhodotorula rubra, andSaccharomyces cerevisiae were exposed to pooled salivary samples contributed by healthy individuals and three groups of outpatients receiving radiation treatment for malignancies, protracted corticosteroid regimes for renal complications, and insulin therapy for diabetes mellitus. Significant variations occurred in fungal growth rates according to phenotype association with specific salivary samples.     

A preliminary study of marine fungi from Abaco Island,the Bahamas

Marine soil, mangrove wood, and free floating algal collections were made in the shallow littoral zone of Abaco Island, The Bahamas. Material was subsequently examined in the laboratory for fungal populations inhabiting seawater shorelines of the island. The study follows previous mycological investigations of Abaco including the keratinophilic fungi (10) and the fresh water fungi (11).