Dramatic impact of the TiO2 polymorph on the electrical properties of ‘stoichiometric’ Na0.5Bi0.5TiO3 ceramics prepared by solid-state reaction

Bulk conductivity (σb) values of nominally stoichiometric Na0.5Bi0.5TiO3 (NBT) prepared by solid-state reaction collated from literature show random variation between 10-6 -10-3 S cm-1 (at 600 °C). This makes it...

Reliability aspects in a dynamic time-to-failure degradation-based model

Although the ordinary time-to-failure degradation-based model has been extensively used in practice, it also has its limitations. In this paper, we consider a time-to-failure degradation-based model recently proposed by Albabtain et al., where a limiting conditional survival probability entertains further stochastic relationships between the failure time and the degree of degradation. In the particular case where the limited survival probability is available for the proportional failure rate model, the model is developed using two well-known degradation paths, namely the additive degradation path and the multiplicative degradation path, each of which has a component of random variation. Preservation of various stochastic orders and aging properties of the random variation component in the model in the described setting is developed. To illustrate the model in the modified design, some examples of interest in reliability are presented.

Chronic care services and variation between Danish general practices: A nationwide cohort study

Background: Little is known about variations in the provision of chronic care services in primary care. Aim: To describe the frequency of chronic care services provided by GPs and analyse the extent of non-random variation in service provision. Design and setting: Nationwide cohort study in Denmark in 2016. Method: Information on chronic care services was obtained from national health registers, including annual chronic care consultations, chronic care procedures, outreach home visits, and talk therapy. The associations between provided services, patient morbidity, and socioeconomic factors were estimated. Service variations were analysed, and excess variation related to practice-specific factors was estimated while accounting for random variation. Results: Chronic care provision was associated with increasing patient age, increasing number of long-term conditions, and indicators of low socioeconomic status. Variation across practices ranged from 1.4 to 128 times more than expected after adjusting for differences in patient population and random variation. Variation related to practice-specific factors was present for all investigated chronic care services. Older patients with lower socioeconomic status and multimorbidity were clustered in practices with low propensity to provide certain chronic care services. Conclusion: Chronic care was provided to patients typically in need of healthcare, i.e. the old, those with multimorbidity, and those with low socioeconomic status, but service provision varied more than expected across practices. GPs provided slightly fewer chronic care services than expected in practices where many patients with multimorbidity and low socioeconomic status were clustered, suggesting inverse care law mechanisms.

Structure, Engagement, and Evolution

This chapter provides a structural description of movie units, defends the notion that movies have evolved in the direction of fitting better our capacities and preferences, and summarizes evidence that the evolved changes have encouraged narrative engagement by viewers. Arguments against any true evolution of cinema concern reproduction, genes, random variation and selection, fashion, progression, speciation, and directionality, and these are discussed and all but the means of reproduction countered. The chapter then summarizes results of the previous chapters about how narrative engagement is attained through sustained attentional focus, understanding the narrative, emotional commitment, and a feeling of presence. It also warns the reader that increased engagement does not mean better movies. Engagement is driven by the narration; the quality of the movie is surely driven by the narrative.

Grammar change

Structurally, cognitive and biological evolution are highly similar. Random variation and constant but blind selection drive evolution within biology as well as within cognition. However, evolution of cognitive programs, and in particular of grammar systems, is not a subclass of biological evolution but a domain of its own. The abstract evolutionary principles, however, are akin in cognitive and biological evolution. In other words, insights gained in the biological domain can be cautiously applied to the cognitive domain. This paper claims that the cognitively encapsulated, i.e. consciously inaccessible, aspects of grammars as cognitively represented systems, that is, the procedural and structural parts of grammars, are subject to, and results of, Darwinian evolution, applying to a domain-specific cognitive program. Other, consciously accessible aspects of language do not fall under Darwinian evolutionary principles, but are mostly instances of social changes.

Deterring Illegal Entry: Migrant Sanctions and Recidivism in Border Apprehensions

During the 2008 to 2012 period, the US Border Patrol enacted new sanctions on migrants apprehended while attempting to enter the United States illegally. Using administrative records on apprehensions of Mexican nationals that include fingerprint-based IDs and other details, we detect if an apprehended migrant is subject to penalties and if he is later reapprehended. Exploiting plausibly random variation in the rollout of sanctions, we estimate econometrically that exposure to penalties reduced the 18-month reapprehension rate for males by 4.6 to 6.1 percentage points off of a baseline rate of 24.2 percent. These magnitudes imply that sanctions can account for 28 to 44 percent of the observed decline in recidivism in apprehensions. Further results suggest that the drop in recidivism was associated with a reduction in attempted illegal entry. (JEL K37, J15, J18)

A Randomness Perspective on Intelligence Processes

We study intelligence processes using a diffusion IRT model with random variability in cognitive model parameters: variability in drift rate (the trend of information accumulation toward a correct or incorrect response) and variability in starting point (from where the information accumulation starts). The random variation concerns randomness across person-item pairs and cannot be accounted for by individual and inter-item differences. Interestingly, the models explain the conditional dependencies between response accuracy and response time that are found in previous studies on cognitive ability tests, leading us to the formulation of a randomness perspective on intelligence processes. For an empirical test, we have analyzed verbal analogies data and matrix reasoning data using diffusion IRT models with different variability assumptions. The results indicate that 1) models with random variability fit better than models without, with implications for the conditional dependencies in both types of tasks; 2) for verbal analogies, random variation in drift rate seems to exist, which can be explained by person-by-item word knowledge differences; and 3) for both types of tasks, the starting point variation was also established, in line with the inductive nature of the tasks, requiring a sequential hypothesis testing process. Finally, the correlation of individual differences in drift rate and SAT suggests a meta-strategic choice of respondents to focus on accuracy rather than speed when they have a higher cognitive capacity and when the task is one for which investing in time pays off. This seems primarily the case for matrix reasoning and less so for verbal analogies.

Investigation on the Mathematical Relation Model of Structural Reliability and Structural Robustness

Structural reliability and structural robustness, from different research fields, are usually employed for the evaluative analysis of building and civil engineering structures. Structural reliability has been widely used for structural analysis and optimization design, while structural robustness is still in rapid development. Several dimensionless evaluation indexes have been defined for structural robustness so far, such as the structural reliability-based redundancy index. However, these different evaluation indexes are usually based on subjective definitions, and they are also difficult to put into engineering practice. The mathematical relational model between structural reliability and structural robustness has not been established yet. This paper is a quantitative study, focusing on the mathematical relation between structural reliability and structural robustness so as to further develop the theory of structural robustness. A strain energy evaluation index for structural robustness is introduced firstly by considering the energy principle. The mathematical relation model of structural reliability and structural robustness is then derived followed by a further comparative study on sensitivity, structural damage, and random variation factor. A cantilever beam and a truss beam are also presented as two case studies. In this study, a parabolic curve mathematical model between structural reliability and structural robustness is established. A significant variation trend for their sensitivities is also observed. The complex interaction mechanism of the joint effect of structural damage and random variation factor is also reflected. With consideration of the variation trend of the structural reliability index that is affected by different degrees of structural damage (mild impairment, moderate impairment, and severe impairment), a three-stage framework for structural life-cycle maintenance management is also proposed. This study can help us gain a better understanding of structural robustness and structural reliability. Some practical references are also provided for the better decision-making of maintenance and management departments.

Personal Proximity and Reactions to Terrorism

In a panel study where one survey was conducted immediately after a terrorist attack in central Stockholm, with over 20,000 participants, we examine the possibility that first-hand experiences with terror increases effects compared to people located elsewhere in Sweden. We use matching and as-if random variation in our data to identify the effect of personal proximity. While we find that people close to the attack perceived themselves as more affected, attesting to the vividness of the experience, we find no evidence of stronger rally effects, greater outgroup dislike, preferences for security policies or emotional effects. The results challenge previous theories on public opinion change in the aftermath of vivid events. In line with prior research, however, the results indicate that public opinion among people across Sweden did change on a range of issues. These general effects occurred uniformly, regardless of geographic location in the country.