Comment on Downing and Oliver's (1973–1974) Experimental Procedure for Establishing a Child's Conception of ‘Word’

This article comments on the experimental procedure-followed by Downing and Oliver (1973–1974) which aims at establishing to what extent a child possesses the conception of ‘word’. The procedure consisted of a ‘Yes–No’ game during which a child was asked to respond to phonemes, syllables, phrases, sentences, short words, long words, and non-verbal sounds, after having been trained to respond with a ‘Yes’ if he heard ‘one of something’. Because low internal consistencies were found in two samples (56 English-speaking and 82 Afrikaans-speaking Grade 1 children) factor analyses were carried out to determine how items in the tests group together. In both samples three factors were extracted. Examination of these factors led to the conclusion that children use different criteria for classifying stimuli at different times. Sometimes they listen for ‘one word’, sometimes for ‘one sound’, depending upon the uncertainty which the stimulus generates. It is stated that it is not possible to know whether the child listens for one word or one sound. It is suggested that the solution lies in presenting the child with long words only, which have been established as being representative of the lexicon of a particular age group.

New TiO2/MgAl-LDH nanocomposites for the photocatalytic degradation of dyes

In this study we report the synthesis of a series of composite nanostructures comprising LDH and TiO2 phases. The materials characterization showed that the LDH crystallites are encapsulated inside the TiO2 matrix after the anatase seeds are deposited on MgxAl-LDHs. The structure in which LDH phase is embedded into anatase matrix is unique bringing important advantages to the photocatalytic performances of the nanocomposites. The photocatalytic activity of the prepared nanocomposites was tested on the degradation of the methylene blue (MB) in aqueous solution. The photocatalytic activities of the nanocomposites were compared with commercial TiO2 nanoparticles Degussa P25. The nanocomposites exhibited superior photocatalytic activity in basic environment because the negatively charged surface of TiO2 nanoparticles at high pH attracts the positively charged methylene blue species.

Post-synthesis deposition of V-zeolitic nanoparticles in SBA-15

A post-synthesis deposition of vanadium silicalite-1 zeolite nanoparticles in the pores of SBA-15 results in a highly ordered hexagonal templated silica material with V-silicalite zeolitic plugs, giving rise to an increased crystallinity of the amorphous mesoporous walls.