Eastern chipmunks (Tamias striatus) and the thirteen-lined ground squirrel (Spermophilus tridecemlineatus) exhibit seasonal changes in body weight and energy intake. The magnitude and timing of these cycles are affected by photo-period. The amount of energy intake was greater in the Eastern chipmunk than it was in the ground squirrel; however, the converse occurred in the seasonal weight changes.
The Schiff base of retinaldehyde (RET) and ethanolamine phosphoglyceride (EPG) appears to be unique. Other Schiff bases of amines and RET absorb spectrally at about 365 nm in aqueous or non-aqueous solvents. RET and EPG in chloroform/methanol exhibit a 336 nm absorbance which we attribute to the absence of the conjugative effect of associated water formed as a result of imino formation. We assume that methanol in chloroform is a hydrogen bonding agent (for water) superior to the Schiff base. The presence of the phosphate portion of EPG appears essential since substitution of sulfate eliminates the effectiveness of the methanol.
Most recent studies of language acquisition have emphasized the child's learning of the abstract syntactic and semantic structures of “linguistic competence.” This study analyzes linguistic acquisition in terms of the semantic-pragmatic unit of the speech act. Findings support the idea that even before children acquire syntax, they develop a “communicative competence,” apart from linguistic competence, and that there are distinct styles of language acquisition best described in terms of the child's “primitive speech acts.”