英国人类胚胎研究管理体制建立的背景及其现实功能分析--兼论日本生命科学技术的社会管理体制结构

随着生命科学技术的发展,出现了很多新的生命伦理学问题.英国的人类胚胎研究管理体制(HFEA)能够提供有益的借鉴.介绍了这一体制建立的背景并对其现实功能进行分析.得出结论:日本应该建立一个生命科学技术的社会管理体制.     

Ambiguity and synonymy effects in lexical decision,naming, and semantic categorization tasks: interactions between orthography,phonology, and semantics

In this article, ambiguity and synonymy effects were examined in lexical decision, naming, and semantic categorization tasks. Whereas the typical ambiguity advantage was observed in lexical decision and naming, an ambiguity disadvantage was observed in semantic categorization. In addition, a synonymy effect (slower latencies for words with many synonyms than for words with few synonyms) was observed in lexical decision and naming but not in semantic categorization. These results suggest that (a) an ambiguity disadvantage arises only when a task requires semantic processing, (b) the ambiguity advantage and the synonymy disadvantage in lexical decision and naming are due to semantic feedback, and (c) these effects are determined by the nature of the feedback relationships from semantics to orthography and phonology.     

Orthographic neighborhood effects in perceptual identification and semantic categorization tasks: a test of the multiple read-out model

How should a word's orthographic neighborhood affect perceptual identification and semantic categorization, both of which require a word to be uniquely identified? According to the multiple read-out model (Grainger & Jacobs, 1996), inhibitory neighborhood frequency effects should be observed in these types of tasks, and facilitatory neighborhood size effects should not be. In Experiments 1 and 2 (perceptual identification), these effects were examined as a function of stimulus visibility (i.e., high vs. low visibility) to provide as full a test as possible of the model's predictions. In the high-visibility conditions, words with large neighborhoods were reported less accurately than words with small neighborhoods, but there was no effect of neighborhood frequency (i.e., whether the word had a higher frequency neighbor). In the low-visibility conditions, low-frequency words with large neighborhoods and low-frequency words with higher frequency neighbors showed superior identification performance. In the semantic categorization task (Experiment 3), words with large neighborhoods were responded to more rapidly than words with small neighborhoods, but there was no effect of neighborhood frequency. These results are inconsistent with two of the basic premises of the multiple read-out model--namely, that facilitatory neighborhood size effects are due to a variable response criterion (the sigma criterion), rather than to lexical selection processes, and that the lexical selection processes themselves produce an inhibitory neighborhood frequency effect (via the M criterion). Instead, the present results, in conjunction with previous findings, suggest that large neighborhoods (and perhaps higher frequency neighbors) do aid lexical selection.     

Effects of speed and accuracy strategy on choice step execution in response to the flanker interference task

The purpose of this study is to examine the effects of a speed or accuracy strategy on response interference control during choice step execution. Eighteen healthy young participants were instructed to execute forward stepping on the side indicated by a central arrow (←, left vs. →, right) under task instructions that either emphasized speed or accuracy of response in the neutral condition. In the flanker condition, they were additionally required to ignore the 2 flanking arrows on each side (→→→→→, congruent or →→←→→, incongruent). Errors in the direction of the initial weight transfer (APA errors) and the step execution times were measured from the vertical force data. APA error was increased in response to the flanker task and step execution time was shortened with a speed strategy compared to an accuracy strategy. Furthermore, in response to the visual interference of the flanker task, speed instructions in particular increased APA errors more than other instructions. It may be important to manipulate the level of the speed-accuracy trade-off to improve efficiency and safety. Further research is needed to explore the effects of advancing age and disability on choice step reaction in a speed or accuracy strategy.     

Cu-based icosahedral quasicrystal formed in Cu-Ga-Mg-Sc alloys

The first-reported Cu-based icosahedral quasicrystal has been found as an almost single phase in Cu 48 Ga 34 Mg 3 Sc 15 alloy annealed at 1043K for 61h. On the basis of our experiments, this icosahedral quasicrystal is expected to be one of the equilibrium phases in this alloy system. Powder X-ray diffraction and electron diffraction experiments revealed that the quasicrystal exhibits a high degree of structural perfection and has a primitive type quasilattice with a six-dimensional lattice parameter a 6D =0.6938nm. The existence of a Cu 3.7 Ga 2.3 Sc-type structure, which is a bcc structure with diffraction symmetry m3, suggests that the Cu-Ga-Mg-Sc quasicrystal is to be classified into a new structural type to which Cd-based icosahedral quasicrystals and the Zn-Mg-Sc quasicrystal belong. This new type has a characteristic local atomic configuration different from both Mackay-type and Bergman-type quasicrystals.     

Arrangement of atomic clusters in a 2/1 cubic approximant in the Al-Zn-Mg alloy system

An arrangement of the so-called Bergman clusters of atoms in a 2/1 cubic crystalline approximant phase, which is closely related to Frank-Kasper-type icosahedral quasicrystals, in an Al-Zn-Mg alloy system is discussed in detail. The 2/1 cubic structure has eight Bergman clusters in its unit cell and the positions of the clusters can be understood as twelvefold sites in the 2/1 cubic approximant of the three-dimensional Penrose lattice. The atomic clusters are located at vertices of two types of rhombohedron, which are formed by six rhombic planes with an edge length of 3 1/2 a 2 /( 2 + 1) 1/2 and a shorter diagonal of 2 a 2 /( 2 + 1) 1/2 ( is the golden ratio and a is a quasilattice constant), which correspond to half a body diagonal and an edge length respectively of the 1/1 cubic approximant unit cell. The present results provide an important key for understanding the arrangements of atomic clusters in icosahedral quasicrystals.     

The impact of feedback semantics in visual word recognition: number-of-features effects in lexical decision and naming tasks

The notion of feedback activation from semantics to both orthography and phonology has recently been used to explain a number of semantic effects in visual word recognition, including polysemy effects (Hino & Lupker, 1996; Pexman & Lupker, 1999) and synonym effects (Pecher, 2001). In the present research, we tested an account based on feedback activation by investigating a new semantic variable: number of features (NOF). Words with high NOF (e.g., LION) should activate richer semantic representations than do words with low NOF (e.g., LIME). As a result, the feedback activation from semantics to orthographic and phonological representations should be greater for high-NOF words, which should produce superior lexical decision task (LDT) and naming task performance. The predicted facilitory NOF effects were observed in both LDT and naming.