Sign determination of the 57 Fe electric-field gradient in Al-based crystals and icosahedral quasicrystals

Abstract

The icosahedral quasicrystals i-AIMn, isomorphically substituted by 28 at.% Fe or by a mixture of (CrFe) atoms, have been studied for the first time by in-field Mössbauer spectroscopy in order to determine the sign and asymmetry parameter of the dominant electric-field gradient (EFG) term. In addition, the orthorhombic o-Al(MnFe) and cubic α- and hexagonal β-Al(MnFe)Si crystalline phases have been studied. We show that the previous Mössbauer results are inadequate for determining whether there are two sites in the quasicrystalline structure in the ratio of the golden number. Our results for i-Al(MnFe) show that the dominant EFG is negative, with an asymmetry parameter of about 0·6. For i-Al(CrFe), essentially no deviations are found from the model of Czjzek or the Gaussian isotropic model. One crystalline phase, the hexagonal β phase, is found to have a very similar quadrupole effect to that found in i-Al(MnFe). In addition it is found that this phase undergoes a change which is at least partly of magnetic origin.     

Are True Scores and Construct Scores the Same? A critical examination of their substitutability and the implications for research results

Relations between constructs are estimated based on correlations between measures of constructs corrected for measurement error. This process assumes that the true scores on the measure are linearly related to construct scores, an assumption that may not hold. We examined the extent to which differences in distribution shape reduce the correlation between true scores on a measure and scores on the underlying construct they are intended to measure. We found, via a series of Monte Carlo simulations, that when the actual construct distribution is normal, nonnormal distributions of true scores caused this correlation to drop by an average of only .02 across 15 conditions. When both construct and true score distributions assumed different combinations of nonnormal distributions, the average correlation was reduced by .05 across 375 conditions. We conclude that theory‐based scales intended to measure constructs usually correlate highly with the constructs they are constructed to measure. We show that, as a result, in most cases true score correlations only modestly underestimate correlations between different constructs. However, in cases in which the two constructs are redundant, this underestimation can lead to the false conclusion that the constructs are ‘correlated but distinct constructs,’ resulting in construct proliferation.     

Effects of instruction on learners’ ability to generate an effective pathway in the method of loci

One of the most effective mnemonic techniques is the well-known method of loci. Learning and retention, especially of sequentially ordered information, is facilitated by this technique which involves mentally combining salient loci on a well-known path with the material to be learned. There are several variants of this technique that differ in the kind of path that is suggested to the user and it is implicitly assumed that these variants are comparable in effectiveness. The experiments reported in this study were designed to test this assumption. The data of two experiments show that participants who are instructed to generate and apply loci on a route to their work recall significantly more items in a memory test than participants who are instructed to generate and apply loci on a route in their house. These results have practical implications for the instruction and application of the method of loci.     

Memories defining the self in Alzheimer’s disease

ABSTRACT

There is a debate over the extent to which personal identity or the self is preserved in patients with Alzheimer’s disease (AD). Autobiographical memory deficits at early stages of AD could contribute to altering patients’ self. However, the nature of the relationship between autobiographical memory deficits and the self in AD has not been much investigated experimentally. In the present study, we aimed to investigate the integrative meaning of self-defining memories (SDMs) in early stages of AD and to analyse its relationship with the self-concept. The results showed that, when compared to the control group, AD patients less frequently extracted meaning from their SDMs and the meaning was less frequently tied to the self. Patients exhibited some altered aspects of the self-concept (i.e., complexity and strength), though some other components still persisted (i.e., valence and certainty). Correlation analyses showed that the impaired integrative meaning in the AD group was correlated with some changes in self-concept. We suggest that integrative meaning may act as a bridge between autobiographical memories and the self-concept, with reduced integration abilities appearing as a potential mechanism for the deterioration of the self-concept in AD.     

Overcoming fixation with repeated memory suppression

Fixation (blocks to memories or ideas) can be alleviated not only by encouraging productive work towards a solution, but, as the present experiments show, by reducing counterproductive work. Two experiments examined relief from fixation in a word-fragment completion task. Blockers, orthographically similar negative primes (e.g., ANALOGY), blocked solutions to word fragments (e.g., A_L_ _GY) in both experiments. After priming, but before the fragment completion test, participants repeatedly suppressed half of the blockers using the Think/No-Think paradigm, which results in memory inhibition. Inhibiting blockers did not alleviate fixation in Experiment 1 when conscious recollection of negative primes was not encouraged on the fragment completion test. In Experiment 2, however, when participants were encouraged to remember negative primes at fragment completion, relief from fixation was observed. Repeated suppression may nullify fixation effects, and promote creative thinking, particularly when fixation is caused by conscious recollection of counterproductive information.     

Perception,Judgment and Individuation: Towards a Metaphysics of Particularity

Abstract

The aim of this paper is to develop a new theory of particularity. In so doing it redefines the concepts ‘perception’ and ‘judgment’. The redefinition occurs once perception is understood as recognition. The move to recognition entails the centrality of repetition. Recognition, it is argued, is a form of repetition. Allowing for repetition necessitates changing the way the relationship between universals and particulars is understood. This is developed via an engagement with Hume and Plato. The article concludes with the outline for a rethinking of the metaphysics of particularity.     

Father and daughter: Identification with difference—a contribution to gender heterodoxy

This paper reinterprets the historical problem of penis envy, that is, the girl's wish to be masculine, in terms of a developmental need to identify with father. Many of the problems posed by earlier analyses of femininity can be clarified by recognizing that before the girl “turns”; to the oedipal father as love object, she looks to the rapprochement father for identification. Identification is not merely an internal structure, it is a relationship in which the subject recognizes herself or himself in the other. In rapprochement, love of the father, who symbolically represents the outside world, takes the place of the practicing toddler's “love affair with the world.”; This identificatory love of the father, initially noticed in boys by Freud and later authors, is often frustrated by the father's absence or inability to recognize the daughter. This frustrated longing takes the penis as its symbol of likeness. The pre‐oedipal over‐inclusive phase of identification with the other sex parent is not superceded by the oedipal constellation, but is integrated with it. Thus identification becomes an important basis of the love of the other: it is not so much the opposite of object love as an important precursor and ongoing constituent of it. Case material illustrates the multiple possibilities of identificatory love and use of phallic symbolism to represent them.     

Knowing at Second Hand

Participants on both sides of the contemporary debate between reductionism and anti‐reductionism about testimony commonly describe testimonial knowledge as knowledge acquired at second hand. I argue that fully appreciating the distinctive sense in which testimonial knowledge is secondhand supports anti‐reductionism over reductionism but also that it supports a particular kind of anti‐reductionism very different from that typically offered in the literature. Testimonial knowledge is secondhand in the demanding sense of being justified by the authority of a speaker where this requires that epistemic responsibility for meeting challenges to the audience's testimonial knowledge is shared between speaker and audience. The epistemic credentials of testimonial knowledge are in this sense importantly interpersonal.