Design of micro-nanoscale bio-inspired hierarchical materials

In this article two mathematical models, force- or energy-based, are proposed for the design of nanoscale bio-inspired hierarchical materials, considering strong or weak interfaces, respectively. Simple formulas describing the dependence of strength, toughness and stiffness on the considered size scale are derived, taking into account toughening biomechanisms. A simple experimental comparison on a new two-level hierarchical grained material is also discussed.     

Indistinguishability, Choices, and Logics of Agency

This paper deals with structures ${\langle{\bf T}, I\rangle}$ in which T is a tree and I is a function assigning each moment a partition of the set of histories passing through it. The function I is called indistinguishability and generalizes the notion of undividedness. Belnap’s choices are particular indistinguishability functions. Structures ${\langle{\bf T}, I\rangle}$ provide a semantics for a language ${\mathcal{L}}$ with tense and modal operators. The first part of the paper investigates the set-theoretical properties of the set of indistinguishability classes, which has a tree structure. The significant relations between this tree and T are established within a general theory of trees. The aim of second part is testing the expressive power of the language ${\mathcal{L}}$ . The natural environment for this kind of investigations is Belnap’s seeing to it that (stit). It will be proved that the hybrid extension of ${\mathcal{L}}$ (with a simultaneity operator) is suitable for expressing stit concepts in a purely temporal language.     

The Church–Fitch knowability paradox in the light of structural proof theory

Anti-realist epistemic conceptions of truth imply what is called the knowability principle: All truths are possibly known. The principle can be formalized in a bimodal propositional logic, with an alethic modality ${\diamondsuit}$ and an epistemic modality ${\mathcal{K}}$ , by the axiom scheme ${A \supset \diamondsuit \mathcal{K} A}$ (KP). The use of classical logic and minimal assumptions about the two modalities lead to the paradoxical conclusion that all truths are known, ${A \supset \mathcal{K} A}$ (OP). A Gentzen-style reconstruction of the Church–Fitch paradox is presented following a labelled approach to sequent calculi. First, a cut-free system for classical (resp. intuitionistic) bimodal logic is introduced as the logical basis for the Church–Fitch paradox and the relationships between ${\mathcal {K}}$ and ${\diamondsuit}$ are taken into account. Afterwards, by exploiting the structural properties of the system, in particular cut elimination, the semantic frame conditions that correspond to KP are determined and added in the form of a block of nonlogical inference rules. Within this new system for classical and intuitionistic “knowability logic”, it is possible to give a satisfactory cut-free reconstruction of the Church–Fitch derivation and to confirm that OP is only classically derivable, but neither intuitionistically derivable nor intuitionistically admissible. Finally, it is shown that in classical knowability logic, the Church–Fitch derivation is nothing else but a fallacy and does not represent a real threat for anti-realism.     

Anticipatory Anxiety of an Imminent Economic Collapse

This article describes a prospective study of 1,200 participants, half of whom were offspring of trauma survivors, and their emotional symptom levels before and after the Corralito, an economic crisis that occurred in Argentina at the end of 2001. The authors report pre- and postcrisis data on anxiety and depression in a group of adult offspring of victims of the Dirty War (1976–1983) in an attempt to ascertain whether they are at greater risk than a control group for developing anxiety and depression in response to an economic crisis. The results indicated the offspring of war victims experienced greater emotional distress than the control subjects before, but not after the imposition of the Corralito.     

Dysfunctional Personal Experiences and Existential Dilemmas

This article presents a theoretical discussion of the results from the research, “An Existential Understanding of Anxiety: An Integration of the Ideas of May, Yalom, and Schneider.” It focuses on the development of dysfunctional experiences according to the theoretical perspectives of Rollo May, Irvin Yalom, and Kirk Schneider. Dysfunctional experiences emerge when human beings experience (implicitly or consciously) different existential dilemmas and are unable to make consistent decisions and confront the experience of anxiety that results from such contact. In this sense, dysfunctional experiences are not developed simply from the consciousness of existential givens, as suggested by Yalom (1980 Yalom , I. ( 1980 ). Existential psychotherapy . New York , NY : Basic Books . [Google Scholar]), but by the dialectical and paradoxical relationship with the following human dilemmas: life versus death, freedom versus determinisms, isolation versus intersubjectivity, meaning versus insignificancy, individuation versus adaptation, and sense of power versus impotence. This idea implies that anxiety and dysfunctional experiences could emerge, in daily life, from the need to take concrete decisions when faced with several possibilities or dilemmas, and not only from the awareness of those possibilities.     

Processing Italian Relative Clauses: Working Memory Span and Word Order Effects on RTs

In this study, the authors aim to clarify whether the subject–object asymmetry in relative clause comprehension is due to the use of parsing strategies (Active Filler Theory) or to a greater memory load generated by object sentences. Two experiments investigate how individual differences in working memory span may influence the reading times of relative sentences in Italian, a language characterized by a flexible structure. The results of Experiment 1 indicate that object extraction is more complex than subject extraction when sentences have a canonical structure. Furthermore, low-span participants have particular difficulties with object relative sentence comprehension. The results of Experiment 2 show that subject-relative clauses with uncanonical structures are more complex to understand than object-relative clauses, and low-span participants have more difficulties than high-span participants in elaborating both subject and object relative clauses. These data seem to be coherent with the Active Filler Theory.     

Running with emotion: When affective content hampers working memory performance

This study tested the hypothesis that affective content may undermine rather than facilitate working memory (WM) performance. To this end, participants performed a running WM task with positive, negative and neutral words. In typical running memory tasks, participants are presented with lists of unpredictable length and are asked to recall the last three or four items. We found that accuracy with affective words decreased as lists lengthened, whereas list length did not influence recall of neutral words. We interpreted this pattern of results in terms of a limited resource model of WM in which valence represents additional information that needs to be manipulated, especially in the context of difficult trials.     

Role of Interactivity in Learning from Engineering Animations

This study examines the pedagogic value of incorporating sophisticated interactivity features into lessons on hand‐held devices. Engineering students (Experiment 1) and non‐engineering college students (Experiment 2) spent 5 min studying an animation showing a six‐step maintenance procedure for a mechanical device called a Power Take‐Off presented on an iPad. In both experiments, students who received high interactivity (i.e., rotation through dragging movements and zoom through pinching movements) reported higher interest but did not show better learning as compared to the low interactivity group (i.e., pause and continue buttons on the touch screen) or no interactivity group. Across two experiments, the interactivity hypothesis was supported in terms of increased interest but not supported in terms of improved learning. Thus, there was not support for the idea that increasing situational interest through high levels of interactivity primes deeper learning processes that produce better learning outcomes. Copyright © 2015 John Wiley & Sons, Ltd.     

Not All Alike: The Distinctive Impact of Voluntary and Involuntary Effort on Stress and Fatigue

Nowadays, little evidence exists on how variations in effort affect worker health, such as stress and fatigue, two important and undesirable outcomes for workers. Then, this paper analyses the impact of different dimensions of effort on stress and fatigue. To do so we use past literature to links the different effort dimensions on employee health. Concretely, the frameworks used in the paper are the one developed by Karasek and Theorell (1990), according to which the different combinations of work demands, competences in decision making and social support determine the stress employees suffer; and the effort-reward imbalance model (ERI Model) of Siegrist (Psychology 1:27–41, 1996). This provides a more sensitive model of stress, as it uses a combination of extrinsic effort and intrinsic effort as predictors of stress. Building on these theoretical models of job stress we argue that one main source of employee stress and fatigue is employee effort. Using a representative Spanish data set, our study reveals that different dimensions of effort have different consequences for workers. Whereas involuntary effort increases both stress and fatigue, voluntary effort entails a decrease in both.