A survey of residual analysis and a new test of residual trend

A survey of residual analysis in behavior‐analytic research reveals that existing methods are problematic in one way or another. A new test for residual trends is proposed that avoids the problematic features of the existing methods. It entails fitting cubic polynomials to sets of residuals and comparing their effect sizes to those that would be expected if the sets of residuals were random. To this end, sampling distributions of effect sizes for fits of a cubic polynomial to random data were obtained by generating sets of random standardized residuals of various sizes, n. A cubic polynomial was then fitted to each set of residuals and its effect size was calculated. This yielded a sampling distribution of effect sizes for each n. To test for a residual trend in experimental data, the median effect size of cubic‐polynomial fits to sets of experimental residuals can be compared to the median of the corresponding sampling distribution of effect sizes for random residuals using a sign test. An example from the literature, which entailed comparing mathematical and computational models of continuous choice, is used to illustrate the utility of the test.     

Social Capital and Fear of Crime in Adolescence: A Multilevel Study

Hierarchical linear modeling was used to examine the relationships between social capital (at the individual, the neighborhood, and the regional levels) and adolescents' fear of crime, while controlling for the main individual (sociodemographics, television viewing, and bullying victimization), neighborhood (neighborhood size and aggregated victimization), and regional (crime rate and level of urbanization) variables. Data were analyzed using a three‐level model based on 22,639 15.7‐year‐old (SD = 0.67) students nested within 1081 neighborhoods and 19 Italian regions. The findings revealed that individual and contextual measures of social capital, modeled at the individual, neighborhood, and regional levels simultaneously, showed negative associations with adolescents' fear of crime. Males and participants with higher family affluence were less likely to feel fear of crime, whereas victimization, both at the individual and neighborhood levels, had a positive association with fear of crime. Strengths, limitations, and potential applications of the study are discussed.     

A theory-based epistemology of modality

We have some justified beliefs about modal matters. A modal epistemology should explain what’s involved in our having that justification. Given that we’re realists about modality, how should we expect that explanation to go? In the first part of this essay, I suggest an answer to this question based on an analogy with games. Then, I outline a modal epistemology that fits with that answer. According to a theory-based epistemology of modality, you justifiably believe that p if (a) you justifiably believe a theory that says that p and (b) you believe p on the basis of that theory.     

The influence of the human TMJ eminence inclination on predicted masticatory muscle forces

Aim of this paper was to investigate the change in masticatory muscle forces and temporomandibular joint (TMJ) reaction forces simulated by inverse dynamics when the steepness of the anterior fossa slope was varied. We used the model by de Zee et al. (2007) created in AnyBody™. The model was equipped with 24 musculotendon actuators. Mandibular movement was governed by the trajectory of the incisal point. The TMJ was modelled as a planar constraint canted 5° medially and the caudal inclination relative to the occlusal plane was varied from 10° to 70°. Our models showed that for the two simulated movements (empty chewing and unilateral clenching) the joint reaction forces were smallest for the eminence inclination of 30° and 40° and highest for 70°. The muscle forces were relatively insensitive to change of the eminence inclination for the angles between 20° and 50°. This did not hold for the pterygoid muscle, for which the muscle forces increased continually with increasing fossa inclination. For empty chewing the muscle force reached smaller values than for clenching. During clenching, the muscle forces changed by up to 200 N.     

Hydrothermal growth of ZnO nanoparticles under different conditions

In this study, a simple low-temperature hydrothermal method was used to synthesize ZnO nanoparticles. The structural, morphological and optical characterizations of the nanoparticles were evaluated with regard to the zinc content. To achieve this, the molar ratios of the precursors were changed from 0.05 to 0.1 M. The structural and morphological analyses showed that all samples had a polycrystalline hexangular wurtzite crystal structure and the shape of the ZnO nanoparticles changed with increasing zinc content. A possible growth mechanism of the ZnO nanoparticles is explained in terms of the zinc content. Optical measurement revealed that the shape of the nanoparticles affects the position of the band-edge emission as well as the shape of the luminescence spectrum.     

Mathematical modelling of nucleation and growth of crystals with buoyancy effects

A complete analytical solution of the integro-differential model describing the nucleation of crystals and their subsequent growth in a binary system with allowance for buoyancy forces is constructed. An exact analytical solution of the Fokker-Planck-type equation for the three-parameter density distribution function is found for arbitrary nucleation kinetics. Two important cases of the Weber–Volmer–Frenkel–Zel’dovich and Meirs kinetics are considered in some detail. It is shown that the solute concentration decreases and the distribution function increases with increasing the melt supercooling (with increasing the depth of a metastable system). It is demonstrated that the distribution function attains its minimum at a certain size of crystals owing to buoyancy forces.     

Short-term and long-term relationships between reflection and performance in teams: evidence from a four-wave longitudinal study

Previous theory and research suggest that team reflection is beneficial for team performance. We argue that results remain inconclusive because prior studies have not accounted for the dynamic nature of this relationship. This paper addresses this research gap by examining time-specific relationships among variables and the intra-team variability of changes across time. In a four-wave longitudinal field study with 97 teams (N = 453 team members) performing a business simulation task, short-term (i.e., autoregressive, cross-lagged effects) and long-term (i.e., latent trajectories) relationships between team reflection and performance were explored. We found evidence that reflection had negative autoregressive effects and that there were direct positive short-term relationships between reflection and performance. Reflection trajectories were seen to decline across time and performance trajectories to increase across time. In addition, teams with either low initial reflection or low initial performance showed higher increases in reflection across time, whilst higher increase in reflection was negatively related to change in performance. Findings are discussed with respect to how they extend the previous literature and what directions they suggest for future research.     

Stressful life events and predictors of post-traumatic growth among high-risk early emerging adults

Stressful life events (SLEs) may elicit positive psychosocial change among youth, referred to as post-traumatic growth (PTG). We assessed types of SLEs experienced, degree to which participants reported PTG, and variables predicting PTG across 24 months among a sample of high-risk, ethnically diverse, early emerging adults. Participants were recruited from alternative high schools (n = 564; mean age = 16.8; 65% Hispanic). Multi-level regression models were constructed to examine the impact of environmental (SLE quantity, severity) and personal factors (hedonic ability, perceived stress, developmental stage, future time orientation) on a composite score of PTG. The majority of participants reported that positive changes resulted from their most life-altering SLE of the past two years. Predictors of PTG included fewer SLEs, less general stress, having a future time perspective, and greater identification with the developmental stage of emerging adulthood. Findings suggest intervention targets to foster positive adaptation among early emerging adults who experience frequent SLEs.     

Temporal generalization gradients following an interdimensional discrimination protocol

We investigated the effects of interdimensional discrimination training in the temporal generalization gradient. In a matching-to-sample task, pigeons learned to choose key S after a T–s houselight sample and key NS in the absence of the houselight sample. For one group of pigeons, T?=?20?s; for another, T?=?10?s. Subsequently, houselight duration was varied to obtain temporal generalization gradients. Results showed that (a) proportion S increased as houselight duration ranged from 0?s to T?s and then remained high for houselight durations longer than T; (b) the gradients were well described by negative-exponential functions; (c) these non-flat gradients were present from the beginning of testing, and; (d) the average gradients obtained with T?=?20?s and T?=?10?s overlapped when plotted in relative time. We conclude that temporal control does not require explicit discrimination training along the temporal dimension, and that temporal generalization gradients obtained with an interdimensional protocol show the scalar property of timing. We discuss how these findings challenge current models of timing.     

An Introduction to Kristof’s Theorem for Solving Least-Square Optimization Problems Without Calculus

Kristof’s Theorem (Kristof, 1970 Kristof, W. (1970). A theorem on the trace of certain matrix products and some applications. Journal of Mathematical Psychology, 7(3), 515–530. https://doi.org/10.1016/0022-2496(70)90037-4[Crossref], [Web of Science ®] , [Google Scholar]) describes a matrix trace inequality that can be used to solve a wide-class of least-square optimization problems without calculus. Considering its generality, it is surprising that Kristof’s Theorem is rarely used in statistics and psychometric applications. The underutilization of this method likely stems, in part, from the mathematical complexity of Kristof’s (1964 Kristof, W. (1964). Die beste orthogonale Transformation zur gegenseitigen Uberfiihrung zweier Faktorenmatrizen. Diagnostica, 10, 87–90. [Google Scholar], 1970 Kristof, W. (1970). A theorem on the trace of certain matrix products and some applications. Journal of Mathematical Psychology, 7(3), 515–530. https://doi.org/10.1016/0022-2496(70)90037-4[Crossref], [Web of Science ®] , [Google Scholar]) writings. In this article, I describe the underlying logic of Kristof’s Theorem in simple terms by reviewing four key mathematical ideas that are used in the theorem’s proof. I then show how Kristof’s Theorem can be used to provide novel derivations to two cognate models from statistics and psychometrics. This tutorial includes a glossary of technical terms and an online supplement with R (R Core Team, 2017 R Core Team (2017). R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing. Retrieved from https://www.R-project.org/ [Google Scholar]) code to perform the calculations described in the text.