Established culture-invariant measures are needed for cross-cultural assessment of verbal and visuospatial speed of processing and working memory across the life span. In this study, 32 younger and 32 older adults from China and from the United States were administered numerically based and spatially based measures of speed of processing and working memory. Chinese superiority on the numerically based tasks was found for younger adults. Age and increasing task demands diminished this cultural effect, as predicted by the framework proposed by D. C. Park, R. Nisbett, and T. Hedden (1999). However, the visuospatial measures of both working memory and speed of processing did not differ cross-culturally for either age group. The authors concluded that these visuospatial measures provide culture-invariant estimates of cognitive processes in East Asian and Western cultures, but that numerically based tasks show evidence of cultural and linguistic biases in performance levels.

Let B 3 ðKÞ ¼ fv

By a ðv v; k; 1Þ-OOC we mean an optical orthogonal code. In this paper, it is proved that an optimal ð4p; 5; 1Þ-OOC exists for prime p 1 ðmod 10Þ, and that an optimal ð4up; 5; 1Þ-OOC exists for u ¼ 2; 3 and prime p 11 ðmod 20Þ. These results are obtained by applying Weil's theorem. #

An H(m, n, 4, 3) is a triple (X, T , B), where X is a set of mn points, T is a partition of X into m disjoint sets of size n and B is a set of 4-element transverses of T , such that each 3-element transverse of T is contained in exactly one of them. If the full automorphism group of an H(m, n, 4, 3) admits an automorphism α consisting of n cycles of length m (resp. m cycles of length n), then this H(m, n, 4, 3) is called m-cyclic (resp. semi-cyclic). Further, if all blockorbits of an m-cyclic (resp. semi-cyclic) H(m, n, 4, 3) are full, then it is called strictly cyclic. In this paper, we construct some infinite classes of strictly m-cyclic and semi-cyclic H(m, n, 4, 3), and use them to give new infinite classes of perfect two-dimensional optical orthogonal codes with maximum collision parameter λ = 2 and AM-OPPTS/AM-OPPW property.

A ð2; 3Þ-packing on X is a pair ðX ; AÞ; where A is a set of 3-subsets (called blocks) of X ; such that any pair of distinct points from X occurs together in at most one block. Its leave is a graph ðX ; EÞ such that E consists of all the pairs which do not appear in any block of A: For a ð6k þ 5Þ-set X a large set of maximum packing, denoted by LMPð6k þ 5Þ; is a set of 6k þ 1 disjoint ð2; 3Þ-packings on X with a cycle of length four as their common leave. Schellenberg and Stinson (J. Combin. Math. Combin. Comput. 5 (1989) 143) first introduced such a large set problem and used it to construct perfect threshold schemes. In this paper, we show that an LMPð6k þ 5Þ exists for any positive integer k: This complete solution is based on the known existence result of Sð3; 4; vÞs by Hanani and that of 1-fan Sð3; 4; vÞs and Sð3; f4; 5; 6g; vÞs by the second author. Partitionable candelabra system also plays an important role together with two special known LMPð6k þ 5Þs for k ¼ 1; 2: r