An ordered arrangement of atom columnar clusters in a pentagonal quasiperiodic lattice of an Al-Ni-Co decagonal quasicrystal

The structure of an Al-Ni-Co decagonal quasicrystal (called the S1-type superstructure), which shows diffraction patterns with superlattice reflections, has been studied by atomic-scale observations of electron microscopy. The structure of the decagonal quasicrystal can be characterized as an ordered arrangement of two kinds of atom columnar cluster with different directions of pentagonal symmetry. A fundamental lattice, which is constructed by connecting all the atom clusters, shows a pentagonal quasiperiodic lattice with a bond length of about 2 nm. The pentagonal lattice is divided into two superlattices, which are constructed by connecting atom clusters with the same directions of pentagonal symmetry, with a bond length of 2     

Structural study of a superlattice Al-Ni-Ru decagonal quasicrystal using high-resolution electron microscopy and a high-angle annular dark-field technique

A high-quality superlattice Al-Ni-Ru decagonal quasicrystal with 0.4nm periodicity, formed in the conventionally solidified Al₇₀Ni₂₀Ru₁₀ alloy, has been studied by high-resolution electron microscopy and a high-angle annular dark-field (Z-contrast) technique. It has been clearly revealed that its structure is characterized as an aperiodically ordered arrangement of decagon-shaped atomic columnar clusters which have a diameter of 2nm and show pentagonal symmetry. On the basis of high-resolution electron microscopy structure images, and the atom-resolution Z-contrast observations which highlight the transition-metal sites, the arrangement of atoms in the superlattice decagonal quasicrystal are proposed.     

Living up to high standards and psychological distress

We argue and demonstrate that setting high standards, an essential aspect of perfectionism, is not associated with maladaptive responses in and of itself. Rather, our findings suggest that people's responses to their perceptions that they consistently fail to meet their own standards are maladaptive. More importantly, in the present survey study (n = 293), we extend previous research by showing that low personal standards and the perception that others are imposing high standards on the self operate in concert to strengthen the link between perceived discrepancy and psychological distress. Furthermore, in support of our moderation‐mediation model, regression analyses provided evidence for the mediating role of generalised self‐efficacy beliefs. Copyright © 2008 John Wiley & Sons, Ltd.     

Structural stability of W2B5 under high pressure

High-pressure structural stability studies have been carried out on tungsten boride W₂B₅ up to maximum pressure of 36 GPa using a Mao-Bell diamond-anvil cell at beamline BR-12 of the ELETTRA synchrotron facility (λ = 0.68881 Å). The hexagonal phase (S.G:P6₃/mmc) of W₂B₅ is stable up to the maximum pressure studied. The bulk modulus is estimated to be ~347 GPa using the Birch–Murnaghan equation of state. The variation of lattice parameters and bond lengths B–B and W–B have been studied and the c-axis is seen to be marginally more compressible than the a-axis.     

When the pressure is up: The assessment of social identity threat in low and high status groups

The hypothesis was tested that whereas members of a low status group show a physiological threat response when evaluating a performance situation on the basis of the status quo, members of high status groups show a physiological threat response when evaluating a possible change of the status quo. Participants were categorized in minimal groups, after which they performed a task on which group-level feedback was given (group status manipulation). Later on during the experiment, a second round of this task was unexpectedly announced (implying a possible change in the group’s status). In line with expectations, participants in the low status condition showed higher blood pressure directly after the status feedback, whereas participants in the high status condition showed a similar response in anticipation of the second round of the task. Results are discussed in terms of social identity theory, and the physiological assessment of threats to social identity.     

Phase transitions of Zr41.2Ti13.8Cu12.5Ni10Be22.5 bulk metallic glass at pressures up to 27 GPa

The phase transitions of Zr_41.2Ti_13.8Cu_12.5Ni₁₀Be_22.5 bulk metallic glass have been investigated under high pressures and at room temperature. Direct resistance measurements in a diamond anvil cell provide evidence of a reversible transition between amorphous and crystalline phases; crystallization events occurred at 24 and 26.2 GPa on uploading, and crystalline-to-amorphous phase transitions were observed at 16 and 10.6 GPa on downloading. The phase transitions were confirmed by transmission electron microscopy observations.     

The relationship of motive disposition and situational incentives to individual differences in choking under pressure

Motive disposition theory posits that individuals exhibit stable differences in their achievement, affiliation, and power motives – shaping their capacity to perceive performance, social affiliative, or competitive contexts as rewarding. Whereas this approach has been employed in research on individual differences in motor performance, it has not been considered in predicting individual differences in choking under pressure. Typical pressure manipulations often use competitive or team settings which also constitute prime examples of power and affiliation incentives. Consequently, we hypothesized participants' affiliation (vs. power) motive to be related to golf putting performance in team (vs. competitive) settings. In addition, due to the performance feedback provided by the task, it should also generally appeal to participants high in achievement motivation. Specifically, after a familiarization phase a total of 115 participants completed a baseline assessment of golf putting performance, followed by an experimental block manipulating the task's incentives (competition, team, control) between participants. Analysis of participants' previously assessed motives revealed that both participants' affiliation and achievement motive were positively related to performance (variable error) under pressure. No effects emerged for the power motive. These findings highlight the role of personality differences in predicting motor performance variability in pressure situations. We discuss the specific contributions of projective and self-report motive measures and touch upon possible avenues for coaches and practitioners to counter choking effects.     

Stability and change in intelligence from age 11 to ages 70, 79, and 87: the Lothian Birth Cohorts of 1921 and 1936

Investigating the predictors of age-related cognitive change is a research priority. However, it is first necessary to discover the long-term stability of measures of cognitive ability because prior cognitive ability level might contribute to the amount of cognitive change experienced within old age. These two issues were examined in the Lothian Birth Cohorts of 1921 and 1936. Cognitive ability data were available from age 11 years when the participants completed the Moray House Test No. 12 (MHT). The Lothian Birth Cohort 1936 (LBC1936) completed the MHT a second time at age 70. The Lothian Birth Cohort 1921 (LBC1921) completed the MHT at ages 79 and 87. We examined cognitive stability and change from childhood to old age in both cohorts, and within old age in the LBC1921. Raw stability coefficients for the MHT from 11-70, 11-79, and 11-87 years were .67, .66, and .51, respectively; and larger when corrected for range restriction in the samples. Therefore, minimum estimates of the variance in later-life MHT accounted for by childhood performance on the same test ranged from 26-44%. This study also examined, in the LBC1921, whether MHT score at age 11 influenced the amount of change in MHT between ages 79 and 87. It did not. Higher intelligence from early life was apparently protective of intelligence in old age due to the stability of cognitive function across the lifespan, rather than because it slowed the decline experienced in later life.     

T-ECHO: model of decision making to explain behaviour in experiments and simulations under time pressure

Objectives: To explain the mechanisms of decision making in sports. The ‘Decision Field Theory’ by Townsend and Busemeyer ((1995). Dynamic representation of decision-making. In R. F. Port & T. von Gelder (Eds.), Mind as motion (p. 101). Cambridge: MIT Press) was applied to a ball game situation.Design/Method: A situation in basketball was simulated and used in two experiments. The simulation was realized using a local neural network (Behav. Brain Sci., 12 (1989) 435) and was based on a decision model T-ECHO (Tactical decision — Explanatory Coherence by Harmonic Optimization). Experiment 1 (n=53) tested decisions in a video-based laboratory decision task. Learning took place by watching video clips and was significantly better for implicit and explicit groups than for a control group. Experiment 2 (n=34) replicated the results by using incidental and intentional learning groups. Finally, comparisons between behaviour output of neural networks and participants' decision making were made.Results: A good fit between simulation and participant behaviour was shown. Time pressure explained preference reversals from a dynamic viewpoint.Conclusions: The use of simulations and decision experiments lead to a fruitful way to understand the mechanisms of decision making in ball games.     

From poor performance to success under stress: working memory, strategy selection, and mathematical problem solving under pressure

Two experiments demonstrate how individual differences in working memory (WM) impact the strategies used to solve complex math problems and how consequential testing situations alter strategy use. In Experiment 1, individuals performed multistep math problems under low- or high-pressure conditions and reported their problem-solving strategies. Under low-pressure conditions, the higher individuals' WM, the more likely they were to use computationally demanding algorithms (vs. simpler shortcuts) to solve the problems, and the more accurate their math performance. Under high-pressure conditions, higher WM individuals used simpler (and less efficacious) problem-solving strategies, and their performance accuracy suffered. Experiment 2 turned the tables by using a math task for which a simpler strategy was optimal (produced accurate performance in few problem steps). Now, under low-pressure conditions, the lower individuals' WM, the better their performance (the more likely they relied on a simple, but accurate, problem strategy). And, under pressure, higher WM individuals performed optimally by using the simpler strategies lower WM individuals employed. WM availability influences how individuals approach math problems, with the nature of the task performed and the performance environment dictating skill success or failure.     

Change of preferences under time pressure: choices and judgements

Students made choices between student apartments judged to be equally attractive. When asked to choose the best apartment in each pair of alternatives, choices made by a group under time pressure were significantly different from those made by another group under no time pressure. The effect was so strong that preference reversals were obtained which could be explained by subjects over-evaluating negative aspects on the most important attribute under time pressure.     

Leaders under pressure: time pressure and state core self-evaluations as antecedents of transformational leadership behaviour

ABSTRACT

This study examines situational antecedents of transformational leadership by (a) studying the effect of time pressure on the emergence of transformational leadership behaviours, and (b) examining the mediating role of leaders’ state core self-evaluations. Twice per day for 10 consecutive working days, 42 leaders reported on their state core self-evaluations, transformational leadership behaviours and the time pressure they experienced, yielding 531 observations. Using multilevel path analysis, we found that time pressure had an indirect effect on transformational leadership through leaders’ state core self-evaluations. This mediated relationship was curvilinear; with time pressure having little to no effect on transformational leadership via state core self-evaluations when time pressure is below a leader’s average level of time pressure. However, once this characteristic average level is exceeded, time pressure has a negative effect on transformational leadership via its negative relationship with state core self-evaluations, and this relationship becomes stronger for increasing levels of time pressure.     

Happiness and self-actualization under conditions of strain: a sample of homeless men

Maslow's contention that happiness includes striving and is more than a hedonistic construct was tested in a sample of 146 homeless men. Since all participants were homeless, environmental experiences can be considered as largely held constant, allowing an examination of personality and happiness under conditions of strain. Principal axis factor analysis with promax and oblique rotations placed scores from the measures Unhappy-Happy and the Brief Index of Self-actualization on the same factor which supported Maslow's idea. Humanistic-existential psychology has interest in the happiness construct particularly regarding the development of human potential.     

Visual recognition under conditions of high and low discrimination redundancy

The purpose of this investigation was to measure the minimum interval for recognition under conditions of high and low discrimination redundancy. The minimum interval for recognition is the briefest interval between two stimuli at which the first stimulus can be processed. Two sets of four digits were used. Digits were selected so that one set exhibited high discrimination redundancy and the other low discrimination redundancy. Ten Ss viewed digits with high discrimination redundancy, and 10 Ss viewed digits with low discrimination redundancy. The minimum interval for recognition for Ss tested with high discrimination redundancy was nearly twice as large as the minimum interval for recognition of the digits with low discrimination redundancy.     

Learning a pressure under conditions of immediate and delayed knowledge of results

The results of a series of experiments on learning to reproduce a precise pressure are described and discussed in relation to a tentative hypothesis about the importance of timing of feedback signals. The evidence supports the contention that a careful analysis of the perceptual aspects of performance is necessary to account for the acquisition and retention of a precise motor response. Whilst the original hypothesis is sustained, other factors leading to the same result are clearly important. New evidence is produced which strongly suggests that cues presented simultaneously in two modalities interact. A possible distinction between sensory feedback which is used to control a response and feedback which cannot so be used, and the relation of this distinction to the learning of the response is also discussed.     

The broad factor of working memory is virtually isomorphic to fluid intelligence tested under time pressure

How much overall variance in fluid intelligence (Gf) can be predicted by four working memory (WM) functions: storage capacity, attention control, relational integration, and updating was investigated under time pressured Gf testing. Confirmatory factor analysis indicated that the broad WM factor, which was subsumed by these four WM functions, shared 83.4% of variance with Gf tested under pressure, whereas a reanalysis of previous data with the same model showed that only 58.2% variance was shared with virtually untimed Gf tests. Moreover, in timed Gf tests, only the easiest, early items contributed to the WM-Gf correlation, whereas in untimed tests also the hardest, late items were linked with Gf. These results suggest that the measurement of “fast” intelligence primarily taps the functions of WM, whereas “slow(er)” intelligence depends also on some other cognitive processes beyond WM.     

Chronic effects of high salt intake and conflict stress on blood pressure in primates

The effects of combined behavioral stress and high dietary salt on blood pressure were examined in baboons (N=4) over the course of 1 year. Either high salt diet (240 mEq Na⁺/day) or conflict stress were administered for 8 to 16 weeks, followed by high salt intake and stress combined. Mean arterial pressure (MAP) increased by 8 mmHg during high dietary salt alone, by 4 mmHg during stress alone, and increased further to 14 mmHg above baseline during combined salt and stress. Control baboons (N=2) had no change in MAP across 47 weeks. The data indicate additive effects of chronic high dietary salt intake and behavioral stress on blood pressure in non-human primates.     

Choking under pressure: self-consciousness and paradoxical effects of incentives on skillful performance

Choking under pressure is defined as performance decrements under circumstances that increase the importance of good or improved performance. A model for choking on coordination and skill tasks is proposed, holding that the pressure increases the conscious attention to the performer's own process of performance and that this increased conscious attention disrupts the automatic or overlearned nature of the execution. Six experiments provided data consistent with this model. Three studies showed that increased attention to one's own process of performance resulted in performance decrements. Three other studies showed similar decrements produced by situational manipulations of pressure (i.e., implicit competition, a cash incentive, and audience-induced pressure). Individuals low in dispositional self-consciousness were shown to be more susceptible to choking under pressure than those high in it.     

论科技发达的今天宗教热何以可能

一、宗教热的表现现代宗教热是指始于20世纪70年代,一直延续至今的一场全球性的宗教信仰狂潮。它主要表现