Three important current areas of research in the field of international comparisons are the construction of price indexes at the basic heading level, price indexes at higher levels of aggregation, and the linking of comparisons across regions. We consider recent innovations in each of these areas. These innovations have largely arisen out of International Comparisons Program (ICP) 2005, and hence we discuss them in this context. We give particular emphasis to the construction of price indexes at the basic heading level, because we believe it is here that the biggest problems lie. For example, the apparently anomalous results obtained for China and India in ICP 2005 can be traced back to problems at the basic heading level. We also highlight some inconsistencies in current ICP methodology and some promising areas for future research that warrant closer scrutiny in the next round of ICP.

Background. Demonstrating specific cognitive impairments in psychotic disorders is difficult. However, specific deficits in memory and executive functions have often been claimed. The Cambridge Neuropsychological Test Automated Battery (CANTAB) tasks of IDED attention-shifting (an executive task) and visuospatial paired associates learning (PAL, a memory task) require intact frontal and temporo-hippocampal functioning, respectively; both have been suggested as markers of disease progress in psychosis.

Method. Seventy-one subjects with a first-episode psychosis or at-risk mental state were assessed on these two tasks during referral to a specialist service, the Cambridge-based CAMEO early intervention team.

Results. Performance on the two tasks was dissociated. Poor performance on the PAL test was associated with increased symptom levels and poorer global function, while failure on the IDED executive test was not found to have significant clinical associations. Duration of illness was not associated with performance on either task.

Conclusions. Visuospatial PAL failure may be a marker of clinical severity at the onset of psychosis while IDED performance may reflect a more stable, trait-like impairment. Dissociated performance on the executive and associative learning tasks may reflect independent, neurally dissociated impairments that do not arise in a fixed order. This may explain some of the heterogeneity of cognitive function seen in early psychosis.

Exposure of Fucus spiralis germlings to precise copper concentrations (0 to 844 nM Cu2+) in chemically defined medium demonstrated a relationship between ultrastructural changes and growth retardation with increasing copper concentration. Electron-translucent vesicles, present in ova, which normally disappear after fertilization, accumulated in germlings exposed to Cu2+ above 10·6 nM, suggesting that copper may inhibit a metabolic pathway involved in cell wall formation which is initiated by fertilization. No membrane damage was observed during the exposure period. During a post-exposure period in copper-free medium, recovery occurred (rhizoid extension, apical hair formation) in germlings previously exposed to concentrations below 106 nM Cu2+ and electron-translucent vesicles became granular and disappeared. It is proposed that the electron-translucent vesicles contain a cell wall precursor and that copper inhibits its incorporation into the cell wall, preventing growth and development of the zygote.