Manganese (IV) oxide-catalyzed electrophilic diamination of electron-deficient alkenes provides an easy synthesis of alpha,beta-diamino acid and ketone derivatives for peptidomimetic studies.

Manganese (IV) oxide was found to catalyze the diamination reaction of alpha,beta-unsaturated esters and ketones with N,N-dichloro-p-toluenesulfonamide and acetonitrile as the halogen and nitrogen sources. The reaction is convenient to be conducted by simply mixing three reactants in the presence of manganese dioxide catalyst and 4 A molecular sieves, and provides an easy access to 1-p-toluenesulfonyl-3-trichloromethyl-4,5-imidazoline derivatives, which are useful building blocks for peptidomimetic studies.

Organization in audition by similarity in rate of change: evidence from tracking individual frequency glides in mixtures.

In audition, sound energy is assigned to separate auditory "streams" following principles of organization that closely parallel the visual gestalt principles that guide the perception of distinct forms or objects. Metzger (1934) provided evidence for organization in vision based on similarity in the velocity of moving forms. If two dots approach one another along one spatial dimension, they may appear to cross and continue beyond their meeting point if their velocities differ; otherwise, they usually appear to change direction abruptly and retrace their movements. If an analogous auditory principle exists, with rate of change in frequency substituted for velocity of movement, two frequency glides that sweep through the same frequency range in opposite directions should be able to perceptually cross if their rates of change differ; otherwise, they should usually appear to change direction and retrace the same frequency region. Four experiments provided data in support of this hypothesis, and the results were consistent across experiments with varying stimuli and methods of presentation. When properties of the stimuli favored organization according to a principle of frequency proximity, the effect of a principle of rate similarity was attenuated but still evident.

A little goes a long way: evidence for a perceptual basis of learning for the noun categories count and mass.

Various theories of learning for the categories count noun and mass noun are compared. It is argued that children assign words to these categories on the basis of intuitions arising from perception that are relevant to Macnamara's (1986) semantic definitions of the categories. These definitions rest on the centrality of identity in the meaning of nouns and the centrality of individuation in the meaning of count nouns but not mass nouns. Empirical evidence is presented that supports the hypothesis that young children classify words as count nouns or mass nouns on the basis of perceptual information about the extension of the words, that is, whether or not the extension consists exclusively of enduring individuals whose discreteness from one another is perceptually salient (count nouns) or not (mass nouns). In an experiment, 48 children with a mean age of 2;10 (S.D. = 0;5) were taught a word for a kind of object (i.e. a perceptually distinct individual) or for a kind of substance (i.e. a collection of small granules). For some children the word was syntactically count and for others it was syntactically mass. Half of the children received incongruous perceptual and syntactic cues. For most of these children, classification of the word was guided by the object- or substance-like appearance of the stimulus despite the presence of incongruent syntactic cues. Syntactic cues influenced classification of the word for a minority of subjects, most of whom were among the oldest in the sample. It is concluded that perceptual information is critical in early decisions about membership in the categories count noun and mass noun.

The effects of physical training on high level spinal lesion patients.

Seven chronically institutionalised high level spinal lesion subjects participated in an exercise program, five days per week for seven weeks. Anthropometry, spirometry and maximum oxygen consumption (VO2 max) was measured initially and at the end of seven weeks. Subjects generally followed a common training program. No significant changes were noted in the anthropometric and spirometric measurements. A significant increase (34%) in minute ventilation was recorded, and this was accompanied by significant increases in VO2 max 0.764 +/- 0.341 to 1.03 +/- 0.419 1 x min-1 (P less than 0.01) and wheelchair treadmill time 502 +/- 340 to 766 +/- 249 sec (P less than 0.05). The exercise program had no significant effect on maximum or recovery heart rates. Many subjects had subjective comments on improved psychological state. The significant changes in VV2 max, VE, and wheelchair treadmill time indicated that high level spinal lesion subjects can exhibit an improved cardiovascular function through regular aerobic exercise.

Late cretaceous (maestrichtian?) silicoflagellates from the alpha cordillera of the arctic ocean.

A Late Cretaceous (probably Maestrichtian) silicoflagellate assemblage has been recovered for the first time from the middle section of a core taken from the Alpha Cordillera in the central Arctic Ocean. The finding of Globigerina pachyderma in the top and very rarely in the bottom part of the core suggests a faulting or slumping process in the area.