Tunability of vortex-like patterns on 180o domain walls in ferroelectric PbTiO3

ABSTRACT

Vortices and antivortices are topological defects that could be exploited in high-density storage devices. Using first-principles calculations, we found vortex-like patterns around charged domain walls that are closely related to the tilt angles of charged 180° domain walls relative to the [100] direction. With decreasing tilt angle, the vortex-like patterns evolve from independent antivortices to vortex-antivortex pairs, and then to the inexistence of vortex or antivortex defects. These findings might promote to understand the atomic scale structures of 180° domain walls and open a new pathway to manipulating vortex structures to obtain novel properties.     

High-resolution electron microscopy observations of microplastic fracture in SiC under ball milling at room temperature

Nanometre-sized kinks and cracks formed in 6H SiC under ball milling (BM) at room temperature have been observed and characterized on the atomic scale using high-resolution electron microscopy (HREM). Observations of the kinks show that numerous positive and negative partials are aligned at either of the kink boundaries, and the stacking sequences in the kink band are considerably different from those in the other areas. It was also observed that the (0001) lattice planes in the kink band are kinked, indicating that microplasticity occurs in the normally brittle material SiC under BM even at room temperature. HREM observations of cracks show that cracks previously observed by transmision electron microscopy are not completely open but are at the initiation stage of fracture. Inside a crack, one residual kink region can be clearly observed, which indicates a correlation between kink and crack, that is a crack evolves from a kink.     

Correlation Weights in Multiple Regression

A general theory on the use of correlation weights in linear prediction has yet to be proposed. In this paper we take initial steps in developing such a theory by describing the conditions under which correlation weights perform well in population regression models. Using OLS weights as a comparison, we define cases in which the two weighting systems yield maximally correlated composites and when they yield minimally similar weights. We then derive the least squares weights (for any set of predictors) that yield the largest drop in R ² (the coefficient of determination) when switching to correlation weights. Our findings suggest that two characteristics of a model/data combination are especially important in determining the effectiveness of correlation weights: (1) the condition number of the predictor correlation matrix, R _xx , and (2) the orientation of the correlation weights to the latent vectors of R _xx .     

The Development of Romantic Partner Involvement and Tolerance of Deviance among Juvenile Offenders: Relevance for Offending Behaviors in Early Adulthood

ABSTRACT

This study sought to elucidate heterogeneity in developmental patterns of romantic relationship characteristics and examine the relevance of patterns for predicting offending in adulthood. Group-based trajectory modeling was used to elucidate trajectory groups describing developmental heterogeneity of odds of having a romantic partner and romantic partners’ tolerance of deviance. Poisson regression was used to estimate the effects of group assignments for predicting offending. Three- and four-group models best fit the romantic partner characteristics data. Consistently high odds of having a romantic partner and consistently seeking partners with high tolerance for deviance was associated with greater offending frequency in adulthood.     

Use of self-organizing maps to study sex- and speed-dependent changes in running biomechanics

BackgroundUp to 79% of runners get injured every year, with higher rates of injuries occurring in females than males. A self-organizing map (SOM) is a type of artificial neural network that can be used to inspect large datasets and study coordination patterns. The purpose of this study was to use an SOM to study the effects of sex and speed on biomechanical coordination patterns.MethodThirty-two healthy runners ran on an instrumented treadmill at their long slow distance speed (LSD) and at speed 30% faster (LSD + 30%). Vertical ground reaction force (vGRF), vertical tibial acceleration, step parameters, electromyograms (EMG) of six lower limb muscles, and joint angles were collected across speeds. Rate of loading (ROL), tibial impact shock (TIS), coupling angle variability (CAV) and movement pattern proportions for hip/knee sagittal and hip frontal / knee sagittal plane couplings, peak EMG, step length, step rate, and knee and ankle joint angle at initial contact were used as an input for the SOM (37 variables).ResultsThe analysis identified four clusters (i.e., running patterns). While males and females showed similar distribution across clusters at LSD (p = .36) and at LSD + 30% (p = .51), females did exhibit a significant (p = .03) shift between clusters as the speed increased from LSD to LSD + 30% whereas males did not (p = .17). The shift was associated with an increase in TIS, ROL, step length, step rate, vastus lateralis EMG, hip flexion/knee extension movement pattern proportion, and a decrease in ST EMG and CAV_IC for hip sagittal/knee sagittal coupling.ConclusionAs running speed increased there was a significant change in the coordination pattern in females, which was characterized by increases in several variables that are purported risk factors for running related injuries.     

Kinetics of diffusion via divacancies in a concentrated random fcc alloy

The diffusion kinetics in a concentrated fcc alloy are described by means of divacancies. The model chosen is the random alloy model with bound divacancies. We show that for the fcc structure the Manning formalism developed originally for monovacancies can be used intact to describe diffusion via divacancies. Monte Carlo simulation results for both tracer and collective correlation factors are in good agreement with the results of the formalism for a wide range of the component atom exchange frequencies with the divacancy except for the slower-moving component.     

A new highly ordered Al-Ni-Ru decagonal quasicrystal with 1.6 nm periodicity

A new decagonal quasicrystal (the D phase) with a period of about 1.6 nm was found to form in conventionally solidified and heat-treated Al₇₅Ni₁₅Ru₁₀ alloys. The electron diffraction patterns of the Al-Ni-Ru D phase exhibit a large number of quite sharp diffraction spots located at precise decagonal symmetry positions, indicating a highly ordered decagonal quasicrystal with a long-range quasiperiodic correlation. The D phase is formed with a composition close to Al₇₄Ni₁₅Ru₁₁, as determined by energy-dispersive X-ray analysis. By means of high-resolution electron microscopy, the structural features of the Al-Ni-Ru D phase, which are obviously different from that of the Al-Pd D phase (a typical decagonal quasicrystal with 1.6 nm periodicity reported previously), have been revealed.     

Experts’ memory superiority for domain-specific random material generalizes across fields of expertise: A meta-analysis

Experts’ remarkable ability to recall meaningful domain-specific material is a classic result in cognitive psychology. Influential explanations for this ability have focused on the acquisition of high-level structures (e.g., schemata) or experts’ capability to process information holistically. However, research on chess players suggests that experts maintain some reliable memory advantage over novices when random stimuli (e.g., shuffled chess positions) are presented. This skill effect cannot be explained by theories emphasizing high-level memory structures or holistic processing of stimuli, because random material does not contain large structures nor wholes. By contrast, theories hypothesizing the presence of small memory structures—such as chunks—predict this outcome, because some chunks still occur by chance in the stimuli, even after randomization. The current meta-analysis assessed the correlation between level of expertise and recall of random material in diverse domains. The overall correlation was moderate but statistically significant (\( \overline{r} = .41,p < .001 \)), and the effect was observed in nearly every study. This outcome suggests that experts partly base their superiority on a vaster amount of small memory structures, in addition to high-level structures or holistic processing.     

Temperature-dependent crack surface tension

The fracture surface energy is calculated for a one-dimensional, exactly solvable model of a crack. The temperature dependence of the crack surface tension is determined on the basis of a self-consistent Einstein approach. It is found that lattice vibrations result in a strong reduction in the crack surface tension.     

Personhood and community

Abstract

Davidson develops an argument that establishes the most basic set-up for rationality. The minimal set-up is a triangle formed by two subjects and an object. Each of the two subjects occupies one of the three angles and the third angle is occupied by a subject matter – that about which the two subjects are in communication with one another. I extend Davidson’s argument somewhat and show how an entire pluralistic community is required for individuals to develop most fully as rational creatures. I do this by showing how the basic conditions for rationality set out by Davidson would start to crumble in conditions such as those set out in Orwell’s Nineteen Eighty-Four. The ideal, as opposed to the minimal, set-up for rationality is not a triangle, but a pluralistic network of subjects. And indeed, the ideal conditions for rationality are to a large extent just that because they allow for the full implementation of Davidson’s minimal set-up.     

Atomic force microscopy investigation of buckling patterns of nickel thin films on polycarbonate substrates

The evolution of buckling patterns of nickel thin films have been studied in situ by atomic force microscopy during cyclic tests composed of uniaxial compression followed by release of the external applied stress. After the first strain cycling, buckling structures evolve from straight-sided wrinkles to varicose patterns characterized by a debuckling of some parts of the film. Further cycling tests reveal that rebonding of the film on its substrate does not occur once decohesion has taken place.     

Consistency of performance-related emotions in elite athletes: Generalizability theory applied to the IZOF model

ObjectivesTo estimate the between- and within-individual consistency of the individual zones of optimal functioning (IZOF)-based emotion profiles describing successful and unsuccessful (sub-standard) performance situations.MethodThe methodology of generalizability theory (GT) was applied to two multifaceted measurement designs in studies of 12 highly skilled ice-hockey players assessed by the 28-item aggregated sport-specific emotion scale (Study 1) and a single-case involving elite soccer player (Study 2) using self-generated individualized emotion scale, respectively.ResultsA unique and specific interaction of emotions (the IZOF-“iceberg” or bell-shaped profile) characterized successful performance situations in both Study 1 and 2. This pattern with predominance of optimal pleasant and unpleasant emotions was consistently revealed in between- and within-individual comparisons. In contrast, failure (or sub-standard performance) could not be characterized in terms of one unique and specific profile. However, the findings clearly motivate future research to identify multiple emotion profiles to conceptualize sub-standard performance. The paper offers hypotheses to guide future research.ConclusionsFindings provided support for conceptualizing performance situations in terms of relatively stable optimal and dysfunctional patterns of interaction of pleasant and unpleasant emotions. Results also demonstrate that GT is a methodology that can accommodate idiographic as well as nomothetic approaches to estimating within-individual and between-individual consistency patterns of performance-related emotions.     

Neck formation processes of nanocrystalline silicon carbide: A tight-binding molecular dynamics study

Atomistic and electronic structures in the process of intergranular neck formation of nanocrystalline silicon carbide (SiC) have been investigated by a tight-binding molecular dynamics method. An order-N parallel algorithm is employed for efficient calculations of electronic energy and forces. We find that a defect-free neck is formed between SiC nanocrystals aligned along [112] axis at T     

George Kelly and the Concept of Construction

Abstract

A distinction is drawn between a predicational and a mediational model. Predication involves the act of affirming, denying, or qualifying broader patterns of meaning in relation to narrower or targeted patterns of meaning. Mediation occurs when something formed outside a process is taken in and comes to play a role in that process that is not intrinsic to it. Fundamental to predication is the fact that meanings under processing are oppositional. George Kelly's theoretical understanding of construction was as a predicational process. The term construction is often confounded with these two views of cognition. Kelly's interpretation of construction is contrasted with the cognitive approach of Piaget and the social constructionist views of Harre and Gergen. It is demonstrated that Kelly's clearer understanding of construction as a predicational process enables him to lend the individual a capacity for personal agency that the other theories fail to capture     

Social Traditionalism and Economic Conservatism: Two Conservative Political Ideologies in the United States

Abstract

The authors surveyed by telephone a random sample of voters in the 1996 presidential election from the Standard Metropolitan Statistical Area of Muncie, IN (“Middletown”; R. Lynd & H. Lynd, 1929) to test a model describing the nature of 2 conservative political ideologies–social traditionalism and economic conservatism. The model, based on functions of attitudes theory, predicted (a) that the 2 political ideologies would appeal to 2 rather distinct constituency groups–the former, to conservative Protestants; the latter, to people of higher incomes–and (b) that social traditionalists would be more dogmatic and economic conservatives would be more open-minded in their respective views. The findings were consistent with those predictions.     

Combinator Logics

Combinator logics are a broad family of substructual logics that are formed by extending the basic relevant logic B with axioms that correspond closely to the reduction rules of proper combinators in combinatory logic. In the Routley-Meyer relational semantics for relevant logic each such combinator logic is characterized by the class of frames that meet a first-order condition that also directly corresponds to the same combinator's reduction rule. A second family of logics is also introduced that extends B with the addition of propositional constants that correspond to combinators. These are characterized by relational frames that meet first-order conditions that reflect the structures of the combinators themselves.     

Sex Offender Height and Pedophilic Interest: A Clarification

ABSTRACT

The authors investigated the relationship between offender height and pedophilic interest in a sample of 22,228 registered sex offenders (RSOs). Concerns have been raised by a former collaborator that some of the data used in the analyses might be unreliable. In this clarification research note, we respond by briefly summarizing our methodology, describing the concerns, and then discussing our rationale for decisions made in the sampling procedures and analyses.     

Influence of Age and Sex on Line Bisection: A Study of Normal Performance with Implications for Visuospatial Neglect

ABSTRACT

Line bisection is an established clinical task used to diagnose visuospatial neglect. To date, few studies have considered the extent to which age and sex as background variables contribute to bisection performance. Both variables affect the neural substrates underlying cognitive processes and hence the behavioural performance of bisection. The purpose of this study was to examine the effects of age and sex on normal bisection performance, using three different line lengths to elucidate the influence of these potential contributing factors. Seventy men and 70 women, divided equally into seven age-cohorts between 14 and 80 years, bisected lines. Results indicated clear age- and sex-related differences both in the magnitude and direction of bisection deviations across the three line lengths. Differences are discussed in terms of neural changes across the adult lifespan including hemispheric differences and hormonally mediated changes.