Adiabatic electron thermal pressure fluctuations in tokamak plasmas.

Electron thermal pressure fluctuations measured in the edge plasma of the Texas Experimental Tokamak Upgrade are a fundamental component of plasma turbulence on both sides of the velocity shear layer. The ratio of specific heats, estimated from fluctuations in electron temperature and electron number density measured simultaneously at the same electrode, indicates that observed fluctuations are adiabatic. The observations are made by means of a novel Langmuir probe technique, the time domain triple-probe method, which concurrently measures multiple plasma properties at each of two electrodes with the temporal and the spatial resolution required to estimate thermodynamic properties in a turbulent plasma.

Object transfer, intersubjectivity and third position repair: early developmental observations of one child.

Interaction sequences are explored which are initiated by either child requests or adult offers of objects. The focus is on those sequences in which the child does not want an object that is passed to her, and on how the child manages such an interactional contingency. Throughout the age range in question, 1;0 to 1;8, the child uses re-requests where this contingency occurs in request sequences. The analysis traces the development of these re-requests and compares them with other forms of re-request. In addition, differences are uncovered as between request and offer sequences concerning the child's ways of dealing with an unwanted object that is passed to her. Linkages are made between these themes and work on third position repair within conversation analysis. Home based video-recordings of one child between the ages of 1;0 and 1;8 constitute the data base for the study.

Offer sequences between parents and young children with Down's syndrome.

Videorecordings were made in the homes of six children with Down's syndrome whose developmental ages ranged between about 1 and 2 years. Analysis of sequences initiated by parental offers to their children suggests that these children's response behaviour is sensitive to both non-verbal aspects of the offerer's behaviour and the context in which the offer is made.

Pointing and interaction initiation: the behaviour of young children with Down's syndrome when looking at books.

Data are derived from videotapes made in the homes of six Down's syndrome children with developmental ages varying between 1;1 and 2;1. The analysis concerns those sequences in which parent and child look at a book together, and more specifically those exchanges where the child initiates communication on a new target on the page. The design of these initiations is examined with respect to their various verbal and non-verbal components. The analysis of pointing, and in particular of point duration, reveals a possible developmental progression from a stage at which point and exchange duration are linked together to one in which the organization of pointing becomes more detached from the exchange as a unit of interaction.

Turn-taking and overlap in the speech of young Down's syndrome children.

This study has examined incidents involving vocal overlap in recordings made in the homes of four 3-year-old Down's children. Previous research has suggested a higher incidence of vocal clashes and interruptions in the interaction of Down's children than in that of non-handicapped children. In our data, the overall incidence of overlaps initiated by the child was higher for the two less advanced children. However, such overlaps do not necessarily indicate poor turn-taking coordination; slight overlaps, and overlaps which occur close to where a speaker had reached a potential completion point in their turn, need to be distinguished from those which begin in the middle of turn-constructional units. The children's behaviour when overlap occurred was also examined. A number of techniques which show a child's awareness of the fact that overlap has occurred were identified. By using overlap-sensitive techniques, a child is treating overlap as a problem to be remedied. While the most advanced child used six such techniques, there was not clear evidence of the least advanced child using any of them.