Solipsism,individualism and cognitive science

Abstract

‘Artificial Intelligence cannot ignore philosophy’ (McCarthy 1988) I shall challenge the claim that good old-fashioned artificial intelligence, or GOFAI (Haugeland 1985) is solipsistic while more recent neural or ‘brain-style’ approaches to AI are not (Rumelhart et al. 1986). After distinguishing GOFAI from connectionism, I will first show that GOFAI is not committed to solipsism but rather to what is more properly called individualism. I argue that the feature of GOFAI which entails individualism is shared by connectionism. Individualism is a metaphysical assumption of both types of AI, one which may indeed be pernicious. It is an assumption which must be located and understood.     

The design and evolution of TurboTurtle, a collaborative microworld for exploring Newtonian physics

TurboTurtle is a dynamicmulti-usermicroworld for the exploration of Newtonian physics. With TurboTurtle, students can alter the attributes of the simulation environment, such as gravity, friction, and presence or absence of walls. Students explore the microworld by manipulating a variety of parameters, and learn concepts by studying the behaviours and interactions that occur. TurboTurtle has evolved into a “group-aware” system where several students, each on their own computer, can simultaneously control the microworld and gesture around the shared display. TurboTurtle's design rationale includes concepts such as equal opportunity controls, simulation timing, concrete vs. abstract controls, recoverability, and how strictly views should be shared between students. Teachers can also add structure to the group's activities by setting the simulation environment to an interesting state, which includes a set of problems and questions. Observations of pairs of young children using TurboTurtle highlight extremes in collaboration styles, from conflict to smooth interaction. Finally, the technical work in making TurboTurtle group-aware is slight, primarily because it was built with a groupware toolkit called GroupKit.     

Differential utilisation of sulfur compounds for H2S liberation by nitrogen-starved wine yeasts

Hydrogen sulfide (H₂S) liberation by Saccharomyces cerevisiae wine yeast was studied as a function of different inorganic sulfurous precursors using a model winemaking system. In a medium analogous to grape juice, and following nitrogen starvation of the yeast culture, a combination of 5 mM sulfate and 300 μM sulfite was more potent than 5 mM sulfate alone as a substrate for H₂S liberation. Sulfate plus sulfite allowed H₂S liberation in greater amounts, at higher rates and over a longer period than sulfate alone, by most of the five yeast strains examined. Nevertheless, a sulfate-only medium still supported the liberation of between 11 and 86% of the H₂S observed in the sulfate plus sulfite medium. After nitrogen depletion of the medium, sulfate uptake by yeast cells was stable for at least 7 h and even increased in a cycloheximide-sensitive manner by ca 35%. The relatively limited formation of H₂S from sulfate is therefore not attributable to losses of sulfate transport by the culture as might occur through elevated permease turnover. Similarly, an inhibition of sulfate transport could not account for the lesser formation of H₂S from sulfate because cultures starved of nitrogen in the presence of sulfate continued to accumulate sulfate in excess of the rates of H₂S liberation. Instead, sulfate deprivation/supplementation experiments implied that limited utilisation of sulfate was due to an inhibition of sulfate reduction to sulfide. Experiments also highlighted a contribution by intracellular sulfur pools of between 35 and 70% to the total H₂S liberated from sulfate by nitrogen starved yeasts. As a component of this pool, glutathione was a precursor for 40% of the H₂S liberated from sulfate-containing medium.     

EFFECT OF CANDELILLA WAX WITH NATURAL ANTIOXIDANTS ON THE SHELF LIFE QUALITY OF FRESH-CUT FRUITS

ABSTRACT

Films formulated with edible natural waxes extracted from Euphorbia antisyphilitica, and additives Aloe vera (4%), ellagic acid (0.01%) and gallic acid (0.01%) were applied to evaluate their effects on the quality of fresh‐cut fruits stored at 5C and at room temperature (21C) for 6 days. The evaluated characteristics were changes in appearance, weight loss, firmness, color, solid content, pH and water activity (A_w). The additives, combined with the natural wax, demonstrated not to cause apparent damage to the fruits. Generally speaking, the films showed better results in comparison with the control. The treatment with A. vera showed the lowest values in weight loss, water migration, A_w, change in pH and firmness. The ellagic acid coating reduced the color change in a greater proportion. The application of these new edible films to fruits extends their shelf life and increases their antioxidant potential, as well as their nutritional quality.

PRACTICAL APPLICATIONS

Edible films elaborated with a natural wax extracted from Euphorbia antisyphilitica complemented with a potent antioxidant ellagic and gallic acids, and Aloe vera extend the shelf life quality and increase the antioxidant potential, as well as the nutritional quality of fresh‐cut fruits and vegetables, giving way to the possibility of producing nutraceutical products in the form of edible biofilms. Potential applications of these films are very attractive because the components are natural and nontoxic, and they are recommended by their low cost, availability and ease of handling. The possibility of using these films on other food products, not necessarily vegetal in origin, could be assayed.