Parallel implementation of a class reasoner

Abstract

One method to overcome the notorious efficiency problems of logical reasoning algorithms in AI has been to combine a general-purpose reasoner with several special-purpose reasoners for commonly used subtasks. In this paper we are using Schubert's (Schubert et al. 1983, 1987) method of implementing a special-purpose class reasoner. We show that it is possible to replace Schubert's preorder number class tree by a preorder number list without loss of functionality. This form of the algorithm lends itself perfectly towards a parallel implementation,¹ and we describe design, coding and testing of such an implementation. Our algorithm is practically independent of the size of the class list, and even with several thousand nodes learning times are under a second and retrieval times are under 500 ms.     

Inducing malolactic fermentation in Chardonnay musts and wines using different strains of Oenococcus oeni

Malolactic fermentations (MLF) were induced in a commercially prepared Washington State Chardonnay must to evaluate the influence of timing of inoculation and pre-culture conditions of Oenococcus oeni strains MCW, EQ-54, and WS-8. The must (pH 3.62, 21.5°Brix) was divided into lots and inoculated with Saccharomyces cerevisiae strain CY3079. Strains of O. oeni were pre-cultured by growing in diluted juice or by re-hydration of freeze-dried strains. Bacteria were inoculated into the musts before (Day 0) or after completion of the alcoholic fermentation (Day 22). Yeast populations exceeded 10⁷cfu/mL in all fermentations that proceeded to dryness. However, the viability of most strains of O. oeni quickly declined after inoculation regardless of the timing of inoculation or the strain used. MLF was induced in the wines inoculated with strains EQ-54 and WS-8 but not with MCW, and the rate depended on the time of inoculation. The method used to prepare bacterial starter cultures had no apparent influence on the completion of MLF. Values for volatile acidity were slightly higher (P< 0.05) in wines inoculated with O. oeni before alcoholic fermentation compared with those inoculated after alcoholic fermentation.     

BEYOND THE ECONOMIC CATALYST DEBATE: CAN PUBLIC CONSUMPTION BENEFITS JUSTIFY A MUNICIPAL STADIUM INVESTMENT?

ABSTRACT: A host of empirical studies have indicated that stadiums and arenas have no significant impact on metropolitan area income or employment. In light of this evidence, the continued proliferation of public investment in sports facilities begs the question: Is there some other justification for this spending, or are policymakers simply acting against the public interest (either irrationally, or in response to political‐economic influences)? A possibility that has not been fully explored is the notion that stadiums and teams generate tangible and intangible consumption benefits that could support some level of public investment. This research builds on a small foundation of literature that is moving discussion beyond the economic catalyst debate by providing an empirical measure of the consumption benefits that accrue to a region as the result of hosting a major league sports team. A contingent valuation survey is used to quantify the consumption benefits that would be associated with the relocation of a major league baseball team to Portland, Oregon. An empirical measure of the region's aggregate willingness to pay for the benefits associated with hosting a team is disaggregated into option and existence values, which can then be compared to any proposed level of public contribution to a new stadium. The findings indicate that consumption benefits would only support a capital investment of approximately $74 million; a figure far smaller than the typical stadium subsidy. The majority of projected benefits are associated with expected public goods and externalities, rather than anticipated attendance, indicating that an equitable financing plan should employ nonuser revenue sources. The level of projected benefits does not vary by locality within the metropolitan area, which argues for a regional cost‐sharing approach. The willingness of residents to pay for stadium construction is tempered by a concern about other pressing social needs in the Portland area and a reaction to the current tax climate.     

NUTRITIONAL COMPOSITION OF WILD EDIBLE CRUCIFER SPECIES

The composition of tender leaves from five species of the family Cruciferae (Alliaria petiolata, Cardaria draba, Cakile maritima, Capsella bursa-pastoris and Sisymbrium irio)from different locations of the southeast of Spain (Almeria) was investigated. The proximate composition, mineral elements (Na, K, Ca, Mg, P, Fe, Cu, Zn and Mn), fatty acids, vitamin C, carotenoids and oxalic acid contents were determined. The available carbohydrate contents ranged from 1.4% - 8.2%. Vitamin C contents were high, specially in Alliaria petiolata (261 mg/100 g). Carotenoid content was relatively high in Alliaria petiolata (13.3 mg). Mineral elements were present at higher concentrations than is common for other green leafy vegetables. Fiber amounts were also remarkable (1.96–5.38 g/100 g). The ω3 series of fatty acids were predominant in the three species (Capsella bursa-pastoris 54.02%). Oxalic acid values and ratios of oxalic acid/Ca were moderate, being higher in C. maritima. We believe that these
species of crucifers could be used for dietary purposes, due to the amount and diversity of nutrients they contain.     

CHARACTERIZATION OF PROTEOLYTIC ACTIVITY IN OCTOPUS (Octopus vulgaris) ARM MUSCLE

A new proteolytic activity assay was devised to avoid the interference of paramyosin which causes gelling during the enzymatic assay. Extremely high autolytic activity was observed in octopus arm muscle, which was 40–500 fold higher than those of various other fish species. The proteinase was inhibited strongly by leupeptin and iodoacetic acid and, to a lesser degree, by transepoxysuccinyl-L-leucylamino (4-guanidono)butane (E-64), indicating the class as a thioi proteinase. The proteinase exhibited optimum activity at pH 2.5 and 40C, although it contained a sulfhydryl group in the active site. Myosin heavy chain was the primary myofibrillar protein which was hydrolyzed during the autolysis of octopus arm followed by paramyosin. Actin showed no signs of hydrolysis during the incubation of up to 8 h. Due to its high affinity for myosin, the enzyme activity should be controlled during processing octopus to ensure the functionality of myosin.     

NOVEL NONTHERMAL METHODS TO REDUCE VIBRIO VULNIFICUS IN RAW OYSTERS

Vibrio vulnificus is a foodborne pathogen associated with consumption of raw oyster. No scientific data is available on postharvest treatments of oyster by ultrasound, ozone, and organic acids. This study was designed to investigate the effects of these treatments on inactivation of V. vulnificus naturally present in the in-shell or half-shelled oysters. In in-shell oysters, these treatments were not effective in reducing the number of this pathogen. Half-shelled oysters treated with ultrasound, and ozone in 2% saline for 30 min had 1 and 1.5 log less V. vulnificus, respectively (p<0.05). Treatment of half-shelled oysters by 50 and 100% lemon juice, 5% citric acid, 10% citric acid, or vinegar for 30 min resulted in a significant reduction (2–4 log) in the numbers of V. vulnificus (p<0.05). Although these methods significantly reduced the population of V. vulnificus in raw oysters, they were not able to reduce the numbers of this pathogen to acceptable level (<3 MPN/g).     

EFFECTS OF FEED DIETS ON DIGESTIVE PROTEASES FROM THE HEPATOPANCREAS OF WHITE SHRIMP (Penaeus vannamei)

Protease activities in the hepatopancreas extract (HP) from white shrimp (Penaeus vannamei) fed one of seven test diets for 30 days were evaluated by several methods. The test diet contained 85% of a reference ration for shrimp and 15% of either anchovy meal, tuna waste meal, deboned white fish meal, langostilla meal, soybean meal, and two menhaden meals as a protein replacer. One of the menhaden fish meals tested (B) had the lowest quality as a shrimp feed based on amino acid analysis. SDS-PAGE zymograms of HP from each of the seven diet groups showed similar proteins activity patterns with casein as substrate. The degree of hydrolysis of casein, measured by pH-stat, was also the same for HP from the seven diet groups (P > 0.05). However, total protease activity measured by azocasein hydrolysis (units/g HP) was higher for the diet group fed the test ration containing tuna waste as a replacer (P > 0.05). Trypsin and chymotrypsin activities measured with synthetic substrates (units/mg protein; units/g HP) from animals reared on the diet with menhaden meal B replacer were greater than in the other diet groups (P < 0.05). This study shows that a relatively small amount (15%) of a specific protein replacer in white shrimp rations can influence the protease activity of shrimp HP. Given that digestive proteases such as trypsin can leach into the muscle of postharvest shrimp and thereby cause softening of the meat, the impact of the rearing diet on postharvest shelf-life should be considered along with the standard measures of feed quality that are used by the fish farmer, i.e. animal growth and heatlh.