Development of children with early language delay.

Four children with early language delays (ELD) were compared to a control group of 12 children with respect to their preschool language abilities from age 2 1/2 to 5 years and their verbal skills at the end of Grade 2. The language-delayed children each initially showed severe and broad impairments in syntactic, phonological, and lexical production. Over time, their deficits became milder and more selective, such that normal or nearly normal speech and language proficiency was exhibited by age 60 months.

Stability-complexity relationships within models of natural systems.

Drawing on the qualitative loop analysis models prepared by Lane for a Delaware Bay plankton community, we evaluated 12 systems that ranged from 14 to 18 entities (population, guild or nutrient). Our approach was to study models of extended trophic biotic communities and examine the stability-complexity issue not only as it exists between systems (the traditional approach) but also with respect to the entities and relationships within a given system. We found no statistically significant inverse relationship for stability and complexity between systems.

Orientation and direction tuning of goldfish ganglion cells.

Orientation and direction tuning were examined in goldfish ganglion cells by drifting sinusoidal gratings across the receptive field of the cell. Each ganglion cell was first classified as X-, Y-, or W-like based on its responses to a contrast-reversal grating positioned at various spatial phases of the cell's receptive field. Sinusoidal gratings were drifted at different orientations and directions across the receptive field of the cell; spatial frequency and contrast of the grating were also varied.

The applicability of the modified bivariate plotting procedure to subjects with functional hearing loss.

The applicability of the modified bivariate plotting procedure proposed by Silman, Silverman, Showers, and Gelfand, 1984, was evaluated on a group of functional hearing-loss subjects under age 44 years. The false-positive rate was 17% and the false-negative rate was 0% for both significant and mild or high frequency sensorineural hearing loss.

Carbohydrate appetite in rats: taste and postingestive factors.

Studies designed to elucidate the role of taste and postingestive factors in the rat's hyperphagic response to carbohydrate solutions are reviewed. Initial experiments revealed that polysaccharide solutions induce as much overeating as do sugar solutions, but that sugars and polysaccharides produce little or no overeating when presented in powder form. Although rats were found to be very attracted to the taste of polysaccharide solutions, as they are to sugar solutions, taste alone does not explain their overconsumption of these solutions.

Effect of naloxone on conditioned suppression in rats.

Painful stimuli are known to engage an endorphin analgesic system that can be reversed by the opiate antagonist, naloxone. Naloxone, then, should increase the effectiveness of aversive unconditioned stimuli (USs) in Pavlovian fear conditioning. Consistent with this hypothesis, naloxone administered during the acquisition of conditioned suppression in rats enhanced posttrial suppression and preconditioned stimulus (pre-CS; context-controlled) suppression.

The potential for community level evaluations based on loop analysis.

In this paper we present results obtained with a computer simulation in which a community, described by Levins in his presentation of loop analysis (Levins, R., 1975, Evolution in communities near equilibrium, in: Ecology and Evolution of Communities, M.L.

Ultrastructural observations on the embryonic development of the integument of Lacerta muralis (Lacertilia, Reptilia).

Integumentary development on the dorsal and ventral aspects of the body of 14, 21, 26, 33, and 40-day incubated embryos of the European Wall Lizard (Lacerta muralis) is described. While the earliest stages of epidermal differentiation resemble those reported for other tetrapods, precocious differentiation of dermal collagen more resembles that of anamniotes than that of birds and mammals. Anchoring complexes comprising cellular components, anchor filaments, and collagen are described, and their possible relationship to the formation of scale anlagen is discussed.

On psycho-linguistic paradigms.

Some frustration and confusion are detectable in the work of those researching the psychology of language. The suggestion is made that the lack of focus is due, in part, to the lack of a dominant paradigm or overall system within which to view recent developments. It appears possible to isolate three broad and conflicting perspectives within the contemporary Zeitgeist: an Association position with behaviorist traditions, a Process approach with origins in general cognitive theory, and a Content approach which has evolved along with the resurgence of a nativist position in linguistic theory.