Visuo-spatial processing in a dynamic and a static working memory paradigm in schizophrenia.

Recent findings suggest that the visuo-spatial sketchpad (VSSP) may be divided into two sub-components processing dynamic or static visual information. This model may be useful to elucidate the confusion of data concerning the functioning of the VSSP in schizophrenia. The present study examined patients with schizophrenia and matched controls in a new working memory paradigm involving dynamic (the Ball Flight Task - BFT) or static (the Static Pattern Task - SPT) visual stimuli. In the BFT, the responses of the patients were apparently based on the retention of the last set of segments of the perceived trajectory, whereas control subjects relied on a more global strategy. We assume that the patients' performances are the result of a reduced capacity in chunking visual information since they relied mainly on the retention of the last set of segments. This assumption is confirmed by the poor performance of the patients in the static task (SPT), which requires a combination of stimulus components into object representations. We assume that the static/dynamic distinction may help us to understand the VSSP deficits in schizophrenia. This distinction also raises questions about the hypothesis that visuo-spatial working memory can simply be dissociated into visual and spatial sub-components.

Elastocaloric effect associated with the martensitic transition in shape-memory alloys

The elastocaloric effect in the vicinity of the martensitic transition of a Cu-Zn-Al single crystal has been studied by inducing the transition by strain or stress measurements. While transition trajectories show significant differences, the entropy change associated with the whole transformation (DeltaSt) is coincident in both kinds of experiments since entropy production is small compared to DeltaSt. The values agree with estimations based on the Clausius-Clapeyron equation. The possibility of using these materials for mechanical refrigeration is also discussed.