POSTMODULAR SYSTEMS: ARCHITECTURAL PRINCIPLES FOR COGNITIVE ROBOTICS

Modular-functional decomposition is a fundamental tenet of computer science. Cognitive robotics, with strong roots in cognitive science and biology,replaces modular-functional decomposition with a more opportunistic approach. Nonetheless, we can extract heuristics with both analytic and synthetic power: architectural principles for postmodular systems. This paper describes three postmodular principles: imagination, shared grounding, and incremental adaptation. It briefly discusses examples of each drawn from existing systems. The paper concludes with an illustration of these three principles used in concert to build a system that progresses first to hand-eye coordination, then to planned complex reaching, and finally to shared attention.     

A RESEARCH NOTE: ANTIOXIDANT EFFECTS ON COLOR OF AN IRRADIATED BOVINE MYOGLOBIN MODEL SYSTEM

To determine whether antioxidants could protect meat color during irradiation, we extracted myoglobin (Mb) from beef hearts, treated it with one of four antioxidants (control, citric acid [CA], ascorbic acid [AA], ethylenediamine tetraacetic acid [EDTA] or propyl gallate [PG]) and irradiated it at 0.00, 1.25, or 2.50 kGy. The myoglobin model system was then evaluated for pH; Commission Internationale de L'Eclairage (CIE) L *, a * and b * values; hue angle; chroma; and thiobarbituric acid reactive substances (TBARS). Adding CA and AA to the beef myoglobin model system resulted in higher L *, a * and b * values than did EDTA and PG, indicating that these samples were lighter, redder and more yellow. EDTA- and PG-containing samples were more similar to controls containing no antioxidants. Hue angle and chroma supported these findings. Irradiation had no effect on pH, color or TBARS. These results indicate that antioxidants have more influence on beef color than irradiation and that the acidic antioxidants have the potential for preserving color.

PRACTICAL APPLICATIONS

Irradiation has the potential to reduce the microbial load on meat products, producing safer foods for consumers. However, a number of reports have indicated that irradiation can compromise the bright, cherry red color of fresh meat. Off-color will result in consumer rejection of products that may be safe. Antioxidants have the potential to preserve meat color by affecting the state of myoglobin; however, studying these effects in vivo is challenging because of the complexity of the system. In this model system, which was devoid of enzymatic reducing systems and equivalents, the acidic antioxidants, ascorbic acid (AA) and citric acid (CA), were most effective in preserving the color of the pigment. These antioxidants appear to have the greatest potential for preserving fresh meat color during irradiation.     

ENZYMATIC DIGESTION OF MUSCLE FROM MENHADEN (BREVOORTIA SPP.) AT DIFFERENT pHs

Solubilization of muscle from South American menhaden, Brevoortia spp., was done with and without added proteolytic enzymes. Pepsin and trypsin were isolated from the stomach and the pyloric caeca of croaker (Micropogonias furnieri) respectively, and used for enzymatic solubilization. Digestion of muscle proteins was carried out at 8C for 20 h with the pH maintained at either 3, 4, 5, 6, 7, 8, 9 or 10. The hydrolytic action was evaluated by measuring the concentration of peptides and proteins solubilized from previously frozen muscle or from lyophilized muscle.
The protein solubility of menhaden muscle was optimum at basic pH; approximately 50–60% of the previously frozen or lyophilized muscle was soluble after incubation without added enzyme at pH 9.0. All of the protein was solubilized from lyophilized menhaden muscle with purified trypsin at pH 10.0. Addition of croaker pepsin to menhaden muscle increased protein solubility by only 10–15%. Digestion of menhaden muscle with both pepsin and trypsin from croaker resulted in a similar increase in protein solubility as obtained by addition of only trypsin.
Similar results were obtained with crude croaker stomach extracts and with purified pepsin, and also with crude pyloric caeca extract and with purified trypsin. Complete solubilization of menhaden muscle with croaker pyloric caeca extract may be an inexpensive way to separate the protein from lipids and prepare a protein isolate from this underutilized specie. Additional work is needed to characterize the functional properties of the menhaden protein extract obtained by digestion of the flesh at alkaline pH with croaker trypsin.