Compound BX Research Articles

The fate of redundant cues in human predictive learning: The outcome ratio effect.

In four experiments, participants were shown a sequence of pairs of pictures of food and asked to predict whether each pair signalled an allergic reaction in a hypothetical patient. The pairs of pictures were used to present two simple discriminations that differed in their outcome ratio. A rich discrimination, 3AX+ BX-, involved three trials in which the compound of two foods, AX, was followed by a reaction, for every trial in which the compound BX was not followed by the outcome. A lean discrimination, CY+ 3DY- was based on the opposite outcome ratio. Upon the completion of this training, participants were asked to rate how likely an individual food would be followed by the allergic reaction. In each experiment, the rating for X was stronger than for Y. This outcome ratio effect poses a challenge for theories of learning that assume changes in associative strength are governed by a common error term, based on the significance of all the cues present on a trial. Instead, the results are consistent with the assumption that changes in associative strength are governed by an individual error term, based on the significance of a single cue.

Structure and properties of polycoordinate planar boron compounds

Polycoordinate planar B compounds BX(n) (X=B, Al, C, N and Si; n=3-8) are optimized at B3LYP/6-311++G (3df,p) theoretical level. For X=B, center B atom can coordinate three to eight atoms, while for X=Al, C, Si, and N, it can only coordinate three to five atoms. The natural bond orbital analysis shows that the center B atom does not violate the octet rule, though the numbers of coordinated atom even reach 8. According to molecular orbital analysis and nucleus independent chemical shift value calculation, it seems that these polycoordinate planar B compounds BX(n) (X=B, Al, C, N, and Si; n=3-8) hold twofold (alpha and pi) aromatic, which play an important role in their stability and keeping all atoms in one plane.