Use of Tree and Graph Structures to Diagram the Logic of Large, Complex Programs

CADD software and other large, highly interactive, complex programs must keep track of many complex relationships and perform the correct operations with both speed and precision based on these relationships, which are often seemingly in conflict. Computers can evaluate only one relationship at a time and the relationships must be evaluated in a specified order that can vary greatly depending on the outcome of each test. Consequently, writing and debugging a program that will perform correctly under a wide variety of inputs can be a frustrating process that at times can seem to produce two "bugs" for each one that is corrected. Tree structures can be employed to maintain a dynamic diagram of the program structure as it is being created. Graph structures, which are closely associated with tree structures, can be employed to simplify the task of developing and implementing the correct program logic and to identify many of the design logic errors at an early stage.
This article describes the use of tree and graph structures to diagram program structure and logic for an educational CADD package that was written by the author.     

Denkprothesen: on programs that reason

This paper considers computer programs that purport to do inference. It finds the essence of their reasoning ability to reside in a particular relationship which exists between the computations described by the texts of those programs and machine-independent formal representations of the theories in which they are said to reason. The principal novelties in the treatment of this question are the use of explicit “abstraction functions” between states of a computation and sets of sentences of a theory, and the notion of global “inference relations” which characterize the set of all inferences of which a system is capable. The central result of the paper is an “arrow-theoretic” characterization of the concept of a knowledge representation, along with the related concept of a knowledge representation realization. The notions of equivalence and subsumption for knowledge representations are defined, as well as equivalence of knowledge representation realizations. Finally, important issues of expression evaluation and control are addressed. The paper concludes with a slogan: “The AI is in the arrows.” Cet article traite des programmes informatiques qui prétendent faire de ľinférence. Ľauteur constate que ľessentiel de leur capacityé de raisonnement réside dans la relation particulière qui existe entre les calculs décrits par les textes de ces programmes et les représentations formelles non liées à un type de machine des théories dans le cadre desquelles ils sont supposés raisonner. Les principales nouveautés dans le traitement de cette question sont ľutilisation de fonctions ?abstraction explicites éntre les etats ?un calcul et les ensembles de phrases ?une théorie, et la notion de relations ?inférence globales qui caractérisent ľensemble de toutes les inférences dont un système est capable. Le principal résultat de cet article est une caractérisation du concept de la représentation des connaissances, ainsi que du concept connexe de la réalisation de la représentation des connaissances. Les notions ?équivalence et de sous-somption pour la représentation des connaissances sont définies, ainsi que ľéquivalence des réalisations de la représentation des connaissances. Enfin, des questions importantes comme ľanalyse et le contrǒle ?expressions sont traitées.     

THERMAL INACTIVATION OF PEA FLOUR LIPOXYGENASE

Lipoxygenase (LOX) was determined in pea flour (9.6% moisture) samples which had been exposed to 90–130°C for 5–45 min, and in crude aqueous extracts (5%; pH 6.7) of previously unheated pea flour which had been exposed to 40–80°C for 5–30 min. The rate of thermal inactivation of pea LOX was shown to follow first-order reaction kinetics. The rate constants, k(min^?1), ranged from 0.005 to 0.252 for the flour, and from 0.068 to 0.267 (60–80°C) for the crude extract. The respective thermodynamic values were: for the energy of activation (E_a), 126.2 and 64.6 kJmole^?1; for the enthalpy of activation (ΔH^?), 123.1 and 61.8 kJmole^?1; for the free energy of activation (Δ^?), 118.0 and 101.4 kJmole^?1. The greater thermostability of LOX in the pea flour under dry-heat conditions, and the observed differences in the E_a, ΔH^? and ΔS^? values, may be accounted for by its possible complexation with other macromolecules and by the structure of the water surrounding the native enzyme.     

CONTROL OF BACILLUS CEREUS IN HIGH-pH CRUMPETS

Studies were performed to determine the effects of sorbic hydroxamic acid (SHA) and mastic oil–ethanol (ME) or water‐ethanol (WE) emitters on the growth of Bacillus cereus in high‐moisture, high‐pH (～8.9) English‐style crumpets stored at ambient temperature (25C). While SHA (3000 p.p.m.), alone or in combination with ME emitters, was effective in inhibiting the growth of B. cereus for 14 days in high‐pH crumpets, only SHA formulated crumpets packaged in air had acceptable sensory scores at the end of storage. However, ME emitters alone were ineffective in controlling the growth of this pathogen. This lack of inhibition in crumpets was attributed to the poor absorption of mastic volatiles from the package headspace into the food matrix. Whatever the reason, these preliminary studies showed that SHA has the potential to control the growth of B. cereus in high‐moisture, high‐pH crumpets without compromising product quality.     

Biomass distribution and nitrate assimilation in response to N supply for Vitis vinifera L. cv. Cabernet Sauvignon on five Vitis rootstock genotypes

Effects of nitrogen (N) supply on biomass distribution as well as N effects on NO₃"assimilation, were examined in two-year-old graftlings of Vitis vinifera L. cv. Cabernet Sauvignon on five rootstocks. Whole-plant biomass in all graftlings more than doubled with increased N supply in solution from 0.25 to 8 mM. Whole plant biomass was also affected by rootstock genotype, but to a lesser extent than by N supply. Biomass allocation to roots declined with increased N supply for all stock-scion combinations, but the magnitude of that response varied with rootstock genotype. Nitrate reductase activity (NRA) in leaves increased with increased N supply for all stock-scion combinations, whereas root NRA increased only up to 1 mM N supply, dropping markedly with additional N. NRA in leaves was one to two orders of magnitude higher than NRA in roots - a difference that increased steadily with increased N supply. By implication, grapevine leaves have a much higher capacity for NO₃^-_- reduction than do grapevine roots, and any contribution by roots to whole-vine NO₃^-_- assimilation declines even further as NO₃^-_- availability increases.     

The Covalent Reactions of Primary Amino Side–chains and Disulphide Bonds in Wool Keratin

The reactions with alkali of the disulphide bonds and the primary amino side–chains in wool have been investigated. Formation of dehydroalamine has been postulated and it has been conclusively identified in an alkali–treated, cystine–containing polypeptide. The mechanism of degradation of cystine in such a peptide has been further investigated and it has been shown that cysteine residues, produced from cystine during degradation, are also capable of degrading further to dehydroalanyl residues. The dehydroalanyl residues so produced are capable of reacting not only with other residues to form LAN and LAL, but also with other species present in the alkaline medium. The influence of amines on the cold setting of wool fibres with thioglycollates and on the dyeability of wool has been studied. Mechanisms are postulated to explain these effects.     

Supercritical CO2 Extraction of Annatto (Bixa orellana) Pigments and Some Characteristics of the Color Extracts

Supercritical CO₂ (SC-CO₂) was used to extract natural food colors from Annatto (Bixa orellana) seeds with different pressures and temperatures. Results from the reverse thin-layer chromatographic separation and GC/MS revealed that SC-CO₂ extracts were composed mainly of bixin, geranylgeraniol and norbixin. Differences in absolute values of solubility parameters (SPD) between these main compounds and SC-CO₂ indicated bixin was more easily extracted than norbixin under conditions used. A higher yield of total pigments was obtained at extraction pressure above 310 bar than at 210 bar and 50°C.     

ASSOCIATION OF DIVALENT IONS WITH PROTEINS OF THE YEAST PLASMA MEMBRANE

The plasma membrane of Saccharomyces carlsbergensis was isolated by lysis of protoplasts and purified by ultracentrifugation in a discontinuous sucrose gradient. Extraction of the purified membranes with buffer in the absence of Mg²+ released 80% of the membrane protein as macromolecular complexes. Solubilization of the membranes in sodium dodecyl sulfate (SDS) caused the majority of the membrane protein to be dissociated from the membrane phospholipid, but after gel filtration some material appeared consistently as an SDS-stable lipo-protein, which aggregated to visible particles if the solubilizing detergent was removed, was not associated with Mg²+-ATPase. Calcium appeared to be involved in the linkage of membrane phospholipid to protein while the reaction of magnesium was at the protein-protein level. Calcium had high affinity of binding to the membrane proteins compared to magnesium ions. Potassium was loosely associated with all membrane proteins. On separation of the membranes by SDS-polyacrylamide gel electrophoresis, 19 polypeptides were distinguished, with molecular weights from 185,000 to 14,000. At least 2 polypeptides with molecular weights of 17,000 and 14,000 were involved in the binding of divalent ions by the membrane.     

Effect of Hydrogen Peroxide and Phenolic Compounds on Horseradish Peroxidase-Catalyzed Decolorization of Betalain Pigments

The effect of hydrogen peroxide and phenolic compounds on the decolorization of betanin and a betaxanthin preparation by horse-radish peroxidase (HRP) was examined. Betanin was decolorized at a greater rate than the betaxanthm pigments and both reactions were H₂O²-dependent. Betaxanthin was more prone to oxidatic decolorization than betanin. 2,4-Dichlorophenol, resorcinol and o-toluidine stimulated the decolorization of both pigments. Guaiacol enhanced the peroxidatic decolorization of both pigments to a small extent, but inhibited the oxidatic breakdown of betaxanthin. Possible implications of these results are discussed.     

Microstructural Evolution in Ca-PSZ and the Room-Temperature Instability of Tetragonal ZrO2

Microstructural evolution of a 7.8 mol% Ca-PSZ, fired at 1870°C and subsequently aged at 1300°C, was studied and correlated with the mechanical properties. The morphology, rafting, and subsequent coarsening of the tetragonal ( t ) ZrO₂ precipitates were of particular interest, as was the instability of some of the t -ZrO₂ particles during room-temperature aging. Precipitate coarsening kinetics (Ostwald ripening) was also studied. Over the limited time range studied (136 h), the interface reaction dominated the kinetics.