introduction: the objective of this study was to compare the shaping ability of three rotary filing systems; constant taper k3 instruments, constant taper profile instruments and progressive taper protaper rotary instruments in clear resin blocks with simulated curved root canals. materials and methods: forty five resin blocks were divided into three groups. group a preparation was conducted wi...

Three experiments compared younger (mean age was 23.7years) and older (mean age was 72.1years) observers' ability to visually discriminate line length using both explicit and implicit standard stimuli. In Experiment 1, the method of constant stimuli (with an explicit standard) was used to determine difference thresholds, whereas the method of single stimuli (where the knowledge of the standard ...

Student difficulties learning algebra are well documented. Many mathematics education researchers (e.g., Bednarz & Janvier, 1996; Davis, 1985, 1989; Vergnaud, 1988) argued that the difficulties students encounter in algebra arose when students were expected to shift suddenly from arithmetic to algebraic reasoning and that the solution to the problem was to integrate opportunities for elementary...

We have used a simple ionic potential to simulate the melting of KCI pseudo-infinite crystal. Two MD simulations, one with constant Volume and the other with constant pressure condition are performed. These results are compared with the previous micro-sample simulation results. In the constant volume simulation the melting temperature increase substantially with increasing pressure. A method fo...