Effects of exact repetition and conceptual repetition on free recall and primed word-fragment completion.

Experiments are reported in which effects of repeating words exactly (e.g., elephant, elephant) or repeating some meaningful aspect—a synonym (pachyderm), an associate (tusk), or a category coordinate (hippopotamus)—were examined on free recall and word-fragment completion. In free recall, large effects of both exact repetition and conceptual repetition were found; the magnitude of the latter was about half that of the former. In contrast, in primed word-fragment completion, repetition effects were rather small, and there was no evidence of indirect (or conceptual) priming. Also, presentation of synonyms, associates, and coordinates in isolation failed to prime word-fragment completion. The results provide further evidence that the basis of primed word-fragment completion is different from that of free recall: the former seems to have a perceptual (or perhaps lexical) basis, whereas the latter relies more on meaningful processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of proportion overlap and repeated testing on primed word fragment completion.

Extended the idea of a proportion overlap (PPO) effect in perceptual identification to a word fragment completion (WFC) test of implicit memory. 80 university students studied a list of words (e.g., cheetah) and received an implicit WFC test (e.g., complete -h--t-h). On the test, the ratio of studied to nonstudied items (PPO) was 0, 25, 50, 75, or 100%. Ss were administered the identical test twice. PPO did not affect priming in WFC, on either the 1st or 2nd test. Also, the completion of studied and nonstudied fragments increased over repeated tests, but priming (the studied–nonstudied rate) remained unchanged. The PPO of items between study and test does not affect performance on primed WFC. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Direct comparison of two implicit memory tests: Word fragment and word stem completion.

In 3 experiments, the implicit memory tests of word fragment and word stem completion showed comparable effects over several variables: Study of words produced more priming than did study of pictures; no levels-of-processing effect occurred for words; more priming was obtained from pictures when Ss imaged the pictures' names than when they rated them for pleasantness; and forgetting rates were generally similar for the tests. A different pattern of results for the first 3 variables occurred under explicit test conditions with the same word fragments or word stems as cues. It is concluded that the 2 implicit tests are measuring a similar form of perceptual memory. Furthermore, it is argued that both tests are truly implicit because they meet the D. L. Schacter et al (1989) retrieval intentionality criterion: Levels of processing of words have a powerful effect on explicit versions of the tests but no effect on implicit versions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Focused-ion-beam-inflicted surface amorphization and gallium implantation--new insights and removal by focused-electron-beam-induced etching

Recently focused-electron-beam-induced etching of silicon using molecular chlorine (Cl(2)-FEBIE) has been developed as a reliable and reproducible process capable of damage-free, maskless and resistless removal of silicon. As any electron-beam-induced processing is considered non-destructive and implantation-free due to the absence of ion bombardment this approach is also a potential method for removing focused-ion-beam (FIB)-inflicted crystal damage and ion implantation. We show that Cl(2)-FEBIE is capable of removing FIB-induced amorphization and gallium ion implantation after processing of surfaces with a focused ion beam. TEM analysis proves that the method Cl(2)-FEBIE is non-destructive and therefore retains crystallinity. It is shown that Cl(2)-FEBIE of amorphous silicon when compared to crystalline silicon can be up to 25 times faster, depending on the degree of amorphization. Also, using this method it has become possible for the first time to directly investigate damage caused by FIB exposure in a top-down view utilizing a localized chemical reaction, i.e. without the need for TEM sample preparation. We show that gallium fluences above 4 × 10(15) cm(-2) result in altered material resulting from FIB-induced processes down to a depth of ～ 250 nm. With increasing gallium fluences, due to a significant gallium concentration close beneath the surface, removal of the topmost layer by Cl(2)-FEBIE becomes difficult, indicating that gallium serves as an etch stop for Cl(2)-FEBIE.