A detailed outline is presented of several convergent points of view connecting the self-dual and anti-self-dual fields with their free data. This is done for the Maxwell and for linearized gravity as exemplifying the approaches. The Sparling equation provides one tool of great power and characterizes one approach. The twistor theory of Penrose yields another equally powerful point of view. The links between these two basic approaches given in this paper provide a unification that allows workers and others with interest (...) in this area to proceed more readily toward the goal of understanding the full nonlinear Einstein equations. (shrink)

In this note we give two new simple derivations of the “good-cut” equation, the equation which governs (complex) self-dual asymptotically flat gravitational fields. One of these derivations is remarkably simple, involving only a few lines. Our main point of interest, however, is in the second derivation. Though it is slightly more complicated, this method of derivation is almost certainly generalizable to cover real asymptotically flat space-times and thus lead to a generalization of the good-cut equation.

We report three experimental studies of reasoning with double conditionals, i.e. problems based on premises of the form: If A then B. If B then C. where A, B, and C, describe everyday events. We manipulated both the logical structure of the problems, using all four possible arrangements (or “figures” of their constituents, A, B, and C, and the believability of the two salient conditional conclusions that might follow from them, i.e. If A then C, or If C then A. (...) The experiments showed that with figures for which there was a valid conclusion, the participants more often, and more rapidly, drew the valid conclusion when it was believable than when it was unbelievable. With figures for which there were no valid conclusions, the participants tended to draw whichever of the two conclusions was believable. These results were predicted by the theory that reasoning depends on constructing mental models of the premises. (shrink)

8 March, now known as International Women’s Day, is a day for feminist claims where demonstrations are organized in over 150 countries, with the participation of millions of women all around the world. These demonstrations can be viewed as collective rituals and thus focus attention on the processes that facilitate different psychosocial effects. This work aims to explore the mechanisms involved in participation in the demonstrations of 8 March 2020, collective and ritualized feminist actions, and their correlates associated with personal (...) well-being and collective well-being, collective efficacy and collective growth, and behavioral intention to support the fight for women’s rights. To this end, a cross-cultural study was conducted with the participation of 2,854 people from countries in Latin America and Europe, with a retrospective correlational cross-sectional design and a convenience sample. Participants were divided between demonstration participants and non-demonstrators or followers who monitored participants through the media and social networks. Compared with non-demonstrators and with males, female and non-binary gender respondents had greater scores in mechanisms and criterion variables. Further random-effects model meta-analyses revealed that the perceived emotional synchrony was consistently associated with more proximal mechanisms, as well as with criterion variables. Finally, sequential moderation analyses showed that proposed mechanisms successfully mediated the effects of participation on every criterion variable. These results indicate that participation in 8M marches and demonstrations can be analyzed through the literature on collective rituals. As such, collective participation implies positive outcomes both individually and collectively, which are further reinforced through key psychological mechanisms, in line with a Durkheimian approach to collective rituals. (shrink)

Since Seligman's 1971 statement that the vast majority of phobias are about objects essential to the survival of a species, a multitude of laboratory studies followed, supporting the finding that humans learn to fear and detect snakes (and other animals) faster than other stimuli. Most of these studies used schematic drawings, images, or pictures of snakes, and only a small amount of fieldwork in naturalistic environments was done. We address fear preparedness theories, and automatic fast detection data from mainstream laboratory (...) data and compares it with ethobehavioural information relative to snakes, predator-prey interaction, and snakes’ defensive kinematics strikes in order to analyse their potential matching. From this analysis four main findings arose, namely that: 1) Snakebites occur when people are very close to the snake and are unaware or unable to escape the bite; 2) Human visual detection and escape response is slow compared to the speed of snake strikes; 3) In natural environments, snake experts are often unable to see snakes existing nearby; 4) animate objects in general capture more attention over other stimuli and dangerous but recent objects in evolutionary terms are also able to be detected fast. The issues mentioned above pose several challenges to evolutionary psychology-based theories expecting to find special-purpose neural modules. The older selective habituation hypothesis (Schleidt, 1961), that prey animals start with a rather general predator image from which specific harmless cues are removed by habituation might deserve reconsideration. (shrink)

The mental model theory predicts that reasoners normally represent what is true, but not what is false. One consequence is that reasoners should make "illusory" inferences, which are compelling but invalid. Three experiments confirmed the existence of such illusions based on disjunctions of disjunctions. They also established a successful antidote to them: Reasoners are much less likely to succumb to illusions if the inferences concern disjunctions of physical objects (alternative newspaper advertisements) rather disjunctions of the truth values of assertions. The (...) results shed light both on the cause of the illusions and on the current controversy among different theories of reasoning. (shrink)

We report three experimental studies of reasoning with double conditionals, i.e. problems based on premises of the form: If A then B. If B then C. where A, B, and C, describe everyday events. We manipulated both the logical structure of the problems, using all four possible arrangements (or ''figures" of their constituents, A, B, and C, and the believability of the two salient conditional conclusions that might follow from them, i.e. If A then C , or If C then (...) A . The experiments showed that with figures for which there was a valid conclusion, the participants more often, and more rapidly, drew the valid conclusion when it was believable than when it was unbelievable. With figures for which there were no valid conclusions, the participants tended to draw whichever of the two conclusions was believable. These results were predicted by the theory that reasoning depends on constructing mental models of the premises. (shrink)

No presente artigo, analisamos as abordagens de António Damásio e Gerald Edelman sobre a consciência e fazemos um paralelo com as teses apresentadas pelo filósofo John Searle. Recorremos também às críticas dos filósofos Bennett e Hacker como pedras de toque da viabilidade de algumas teses. Desse modo, apresentamos uma revisão sistemática da obra de Damásio, Edelman e Searle, a fim de promover um diálogo produtivo entre as ideias defendidas por estes autores, os quais, segundo nossa interpretação, assumem uma teoria do (...) campo unificado da consciência. (shrink)

If Unamuno had been able to choose how to be remembered, he would have wanted him to be a poet. This book wants to do justice to that happy possibility. But above all because Unamuno was a poet in the highest sense: he was while writing the same essay as a novel, or theater, letter or verse, and he was also a poet when he passionately lived all the facets of his intense existence. His intellectual work was poetic and his (...) personal relationships, as well as his political activity, also responded to that peculiar Unamunian aesthetic in which the vital horizon is inescapably confused with the tasks of thought." --Translated from back cover. (shrink)

People seem to differ in their visual search performance involving emotionally expressive faces when these expressions are seen on faces of others close to their age compared to faces of non-peers, known as the own-age bias. This study sought to compare search advantages in angry and happy faces detected on faces of adults and children on a pool of children and adults. The goals of this study were to examine the developmental trajectory of expression recognition and examine the development of (...) an OAB. Participants were asked to find a target face displaying an emotional expression among eight neutral faces. Results showed that children and adults found happy faces significantly faster than angry and fearful faces regardless of it being present on the faces of peers or non-peers. Adults responded faster to the faces of peers regardless of the expression. Furthermore, while children detected angry faces significantly faster compared to fearful ones, we found no such difference in adults. In contrast, adults detected all expressions significantly faster when they appeared on the faces of other adults compared to the faces of children. In sum, we found evidence for development in detecting facial expressions and also an age-dependent increase in OAB. We suggest that the happy face could have an advantage in visual processing due to its importance in social situations and its overall higher frequency compared to other emotional expressions. Although we only found some evidence on the OAB, using peer or non-peer faces should be a theoretical consideration of future research because the same emotion displayed on non-peers’ compared to peers’ faces may have different implications and meanings to the perceiver. (shrink)

\ of monadic m-generalized Łukasiewicz algebras of order n -algebras), namely a generalization of monadic n-valued Łukasiewicz algebras. In this article, we determine the congruences and we characterized the subdirectly irreducible \-algebras. From this last result we proved that \ is a discriminator variety and as a consequence we characterized the principal congruences. In the last part of this paper we find an immersion of these algebras in a functional algebra and we proved that in the finite case they are (...) isomorphic. This last result allows to show a new functional representation for monadic n-valued Łukasiewicz algebras. Finally, we define the notions of \-algebra of fractions and maximal algebra of fractions and we prove the existence of a maximal \-algebra of fractions for an \-algebra. (shrink)