Temporal evolution of internal memory states in a terrestrial mollusk, Limax flavus, was studied using cooling-induced retrograde amnesia. The slug was conditioned to avoid carrot odor by temporally correlated presentation of carrot juice and a bitter-taste stimulus of quinidine sulfate. We could induce retrograde amnesia by cooling of the conditioned slug immediately after the training trial. Thus, we studied the memory states in the slug using the retrograde amnesia according to strategies used in the studies of memory states in mammals or insects. In the early process of memory acquisition, at least two distinctive memory states were observed, short-term memory and long-term memory (LTM). For LTM, two states were also observed. One was a reactivated state of LTM, which was sensitive to the cooling used to induce the amnesia. The other was a so-called resting state of LTM, which was insensitive to cooling. A few days after memory acquisition, further evolution was observed in that the amnesia could not be induced even if the memory trace was reactivated. The results obtained in Limax flavus was comparable with those obtained in a variety of animals.

The MWCX showed similar levels of functionality and safety to HF, as well as the advantages offered by the use of microwave energy. Microwave devices might be used in the majority of applications for which traditional energy devices are used.

The change in memory state in the terrestrial slug Limaxflavus was studied using cooling-induced retrograde amnesia. Slugs were first conditioned to avoid carrot odor and then a second conditioning procedure was applied 1, 3, 6, or 7 days after the first conditioning trial. Cooling the slugs to -1~ on day 7 immediately after the presentation of the odor used in the conditioning resulted in retrograde amnesia in the slugs that were subject to a second conditioning on day 6 or 7, but not in slugs that were subject to a second conditioning on day 1 or 3. Next, second-order conditioning was used as the second conditioning procedure to distinguish the memory acquired in the first conditioning from that acquired in the second conditioning and similar results were obtained. These results suggest that the reactivation of memory altered the memory state from a cooling-insensitive state to a cooling-sensitive one. A possible model for memory states is discussed.

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The lexicographic bi-criteria combinatorial food packing problem to be discussed in this paper is described as follows. Given a set I = {i | i = 1, 2, . . . , n} of current n items (for example, n green peppers) with their weights w i and priorities γ i , the problem asks to find a subset I (⊆ I) so that the total weight i∈I w i is no less than a specified target weight T for each package, and it is minimized as the primary objective, and further the total priority i∈I γ i is maximized as the second objective. The problem has been known to be NP-hard, while it can be solved exactly in O(nT ) time if all the input data are assumed to be integral. In this paper, we design a heuristic algorithm for the problem by applying a data rounding technique to an O(nT ) time dynamic programming procedure. We also conduct numerical experiments to examine the empirical performance such as execution time and solution quality.