The aim of this study was to determine the effects of Van Hiele's phases of learning using tangrams on 3rd grade primary school students' levels of geometric thinking at the first (visual) and second (analysis) level. The study further investigated if high, moderate and low ability students acquire better mastery in geometric thinking at the end of tangram activities. Pre-test and post-test single group experimental design was employed in the study. A total of 221 students enrolled in Grade Three during the 2013 educational year formed the sample. The students learned Two-dimensional geometry and Symmetry through the Van Hiele's phases of learning using tangram. A geometric thinking test was administered to students before and after the intervention. The intervention took place for 3 hours. Paired samples t-tests comparing the mean scores of geometric thinking pre-test and the post-test were computed to determine if a significant difference existed. One-way Multivariate Analysis of Variances (MANOVA) was conducted to compare the students' pretest and posttest mean scores across the three groups: high, moderate and low ability students. The results found that there were significant differences between pre-test and post-test in students' geometric thinking. It was also found that Van Hiele's phases of learning using tangrams was able to significantly promote geometric thinking in the van Hiele's first (visual) and second (analysis) level among high, moderate and low ability students. Low ability students were observed to have the greatest improvement score compared to moderate and high ability students. Thus, the Van Hiele's phases of learning using tangram can be applied in primary school mathematics to help students achieve better level of geometric thinking.

The purpose of this work was to determine if the fine specificity of T cells differed between mice immunized with an antigen in a T helper 1 (Th1) cytokine-dominated environment as compared with a T helper 2 (Th2) cytokine-dominated environment. It was found that splenic T cells from mice immunized with mycobacterial heat-shock protein (hsp 65) and interleukin-12 (IL-12) produced less interleukin-4 (IL-4) and more interferon-gamma (IFN-gamma) in response to stimulation with hsp 65 in vitro than did T cells from mice immunized with hsp 65 alone. The T-cell proliferative response to hsp 65 did not differ between the two groups of mice, although the responses were higher than those of T cells from non-immunized mice. Strikingly, T cells from mice given hsp 65 and IL-12 gave significantly higher responses to six peptides (corresponding to the sequence of hsp 65) to which T cells from mice immunized with hsp 65 alone did not respond. It is considered that different epitopes are presented to T cells (possibly owing to changes in antigen processing) if the environment is shifted, by IL-12, from Th2 towards Th1 cytokines.