The problem of the additive constant and eigenvalues in metric multidimensional scaling

This paper is concerned with the additive constant problem in metric multidimensional scaling. First the influence of the additive constant on eigenvalues of a scalar product matrix is discussed. The second part of this paper is devoted to the introduction of a new formulation of the additive constant problem. A solution is given for fixed dimensionality, by maximizing a normalized index of fit with a gradient method. An experimental computation has shown that the author's solution is accurate and easy to follow.     

Phase transformation of germanium by processing through high-pressure torsion: strain and temperature effects

Germanium has been processed by high-pressure torsion (HPT) under a nominal pressure of 24 GPa at room temperature and cryogenic temperature. The samples processed at room temperature were composed of a diamond-cubic Ge-I phase and a metastable tetragonal Ge-III phase. The formation of Ge-III was significantly suppressed and Ge-I and an amorphous phase, in addition to a small amount of body-centred-cubic Ge-IV, appeared in the case of cryogenic HPT processing at 100 K. The Ge-IV phase gradually disappeared at room temperature. These results indicated that shear strain and thermal energy are important for promoting the formation of Ge-III.     

Functional imaging of working memory and peripheral endothelial function in middle-aged adults

The current study examined the relationship between a prognostic indicator of vascular health, flow-mediated dilation (FMD), and working memory-related brain activation in healthy middle-aged adults. Forty-two participants underwent functional magnetic resonance imaging while completing a 2-Back working memory task. Brachial artery endothelial-dependent flow-mediated dilation (FMD) was assessed using B-mode ultrasound. The relationship between FMD and task-related brain activation in a priori regions of interest was modeled using hierarchical linear regression. Brachial FMD, was significantly related to reduced working memory-related activation in the right superior parietal lobule (β = 0.338, p = 0.027), independent of age, sex, systolic blood pressure, and full scale IQ (F(5, 36) = 2.66, p = 0.038). These data provide preliminary support for the association between a preclinical marker of endothelial dysfunction and cerebral hemodynamic alterations in healthy middle-aged adults. Considering the modifiable nature of endothelial function, additional investigations on the prognostic significance of FMD on future cognitive impairment are warranted.     

When remembering the past suppresses memory for future actions

Remembering planned actions at the correct time in the future is an integral component of prospective cognition. Recent studies on future remembering have led to suggestions that prospective cognition might be based on past experience. To test this hypothesis, we focused on retrieval-induced forgetting (RIF), which usually indicates that remembering past events suppresses memory for related but different past events. The current study assessed RIF in two kinds of event-based prospective memory (PM) tasks using either focal or non-focal cues for ongoing tasks. Participants studied six members from each of eight taxonomic categories and then practiced recalling three of the six members from four of the eight categories using category-stem cues. This retrieval practice suppressed the detection of non-practiced members of the practiced categories during the PM task with non-focal cues (Experiment 1) but not with focal cues (Experiment 2). The results suggest that recall of certain items inhibits the function of the others as PM cues, but only if the PM task does not largely share its processing with the ongoing task.     

Same-different reaction times studied with a flash masking technique

The reaction times (RT) needed to report whether letters were the same or different were measured using a very long exposure of the target and a very brief exposure of a flash mask. Two letters were presented simultaneously in Experiment 1. No effect of response category (same vs. different) was found, although a clear-cut luminance-dependent masking effect was present. Letter number was manipulated in Experiment 2. A three-way interaction was found among response category, number of letters, and stimulus onset asynchrony (SOA). The more difficult task produced longer RTs for “different” judgments than for “same” judgments, particularly at intermediate SOAs. These data are compared with information processing models of perception.     

Lexical decomposition of complex Kanji characters in Japanese readers

Summary The study investigates the question whether during recognition of a complex Kanji character readers also access the meaning of opaque components of the character. The experiment used a speeded semantic-categorization task of two characters, in which readers were requested to decide whether two characters represented words related in meaning or not. The control pairs consisted of (a) graphically similar, but semantically unrelated, characters, and (b) a simple character and a complex character, of which the simple character was a component (part-whole relation), the two characters being again semantically unrelated. The critical pairs consisted of two characters unrelated in meaning, one of which contained an opaque component element related in meaning to the other character. A corresponding trial with English and its alphabetic system would be to ask a subject to decide whether boycott is related in meaning to girl or not. In this condition the subject is expected to give a No response, but if the pseudocomponent boy is activated, interference could occur. (If boy is recovered during recognition of the pseudocompound boycott, the appropriate No response for boycott-girl could become more difficult to take.) The result of the experiment indicated interference in all three conditions (graphically similar characters, part-whole related characters, and opaque-component related characters. Thus, in an analogous task with alphabetic material, it would be more difficult to say No about the existence of a semantic relation between (a) tree and free, (b) boy and boycott, and (c) boycott and girl. The last result can be interpreted as offering evidence for the activation of the opaque component upon recognition of the complex character.This account is somewhat oversimplified. It is not always easy to determine which is a radical in a complex character. A higher radical can in fact be a combination of a lower radical with the addition of one or more strokes.     

The Frame Constraint on Experimentally Elicited Speech Errors in Japanese

The so-called syllable position effect in speech errors has been interpreted as reflecting constraints posed by the frame structure of a given language, which is separately operating from linguistic content during speech production. The effect refers to the phenomenon that when a speech error occurs, replaced and replacing sounds tend to be in the same position within a syllable or word. Most of the evidence for the effect comes from analyses of naturally occurring speech errors in Indo-European languages, and there are few studies examining the effect in experimentally elicited speech errors and in other languages. This study examined whether experimentally elicited sound errors in Japanese exhibits the syllable position effect. In Japanese, the sub-syllabic unit known as “mora” is considered to be a basic sound unit in production. Results showed that the syllable position effect occurred in mora errors, suggesting that the frame constrains the ordering of sounds during speech production.