Failure mechanism in porous materials under compression: crackling noise in mesoporous SiO2

The failure mechanism of porous materials under uniaxial stress has been investigated experimentally. Microporous SiO₂, Vycor, has been subjected to slowly increasing compressive uniaxial stress with stress rates between 0.2 and 12.2?kPa/s. With increasing stress the strain changes stepwise with acoustic emission correlated with each volume collapse. The acoustic emission followed the characteristics of ‘crackling noise’ with a power law distribution over an exceptionally large interval of 6 decades at the slowest stress rate. The power law exponent is ?1.39. Possible applications in mining industry and others are discussed.     

Catharsis: Psychoanalysis and the theatre

The notion of catharsis, in relation to tragedy, was introduced by Aristotle in his work Poetics. Over the centuries, Aristotle's innovative and enigmatic reference to this process has been widely commented on and given rise to intense controversy. In 1895, Freud and Breuer reconsidered this notion in their Studies on Hysteria, where they present the so-called cathartic therapeutic method. It is not, however, this aspect of psychoanalytical theory that the author of this article seeks to elucidate: drawing on a detailed study of the references to tragic catharsis in the work of Freud and Lacan, the author proposes to examine their implications for psychoanalytic treatment.With specific reference to Freud's article Psychopathic characters on the stage (1905) and Lacan's commentary on Sophocles' Antigone (1960), the author argues that catharsis is to be understood not so much as a mechanism of discharge linked to abreaction, but rather as the actual analytic process itself during which the Subject is 'unveiled' and thus faced with the enigma of his own desire.     

Identity Processes in Collective Action Participation: Farmers' Identity and Farmers' Protest in the Netherlands and Spain

This study tested the assumption that a sense of collective identity stimulates participation in collective action. Contextual circumstances supposedly make a collective identity more salient and compel people to act as members of the group; protest participation is more likely among people with a strong collective identity. Group identification and participation in identity organizations were used as indicators of collective identity in a study of 248 farmers from Galicia (Spain) and 167 farmers from the Netherlands. The farmers were interviewed three times at intervals of 1 year. The longitudinal design also allowed a test of causality. A sense of collective identity appeared to stimulate preparedness to take part in farmers' protest. Action preparedness leads to action participation, which in turn appears to foster collective identity.     

Overdispersion tests in count-data analysis

Count data are commonly assumed to have a Poisson distribution, especially when there is no diagnostic procedure for checking this assumption. However, count data rarely fit the restrictive assumptions of the Poisson distribution. The violation of much of such assumptions commonly results in overdispersion, which invalidates the Poisson distribution. Undetected overdispersion may entail important misleading inferences, so its detection is essential. In this study, different overdispersion diagnostic tests are evaluated through two simulation studies. In Exp. 1, the nominal error rate is compared under different sample sizes and lamda conditions. Analysis shows a remarkable performance of the chi2 df test. In Exp. 2 and 3, statistical power is compared under different sample sizes, lamda, and overdispersion conditions. Chi2 and LR tests provide the highest statistical power.     

Q-Coh: A tool to screen the methodological quality of cohort studies in systematic reviews and meta-analyses

The evaluation of the methodological quality of primary studies in a systematic review is a key process to enhance the likelihood of achieving valid results. When considering non-randomized designs as cohort studies, this process becomes even more critical, since these designs are more susceptible to bias than randomized controlled trials are. Taking this into account, a tool, named Q-Coh, was designed with the aim to screen the methodological quality of the primary studies with a cohort design priming specificity over sensitivity in a reasonable application time. After applying it to 21 prospective cohort studies by three raters, all domains had a moderate to good agreement, with all except one of them having statistically significant kappa values. Despite there is no gold standard for the methodological quality, arguments supporting its validity are given. Future research should assess the psychometric properties of Q-Coh in the context of real meta-analyses, evaluate the influence of the raters’ substantive and methodological expertise on these properties, and explore different ways of including the domains-based ratings of the quality provided by Q-Coh into meta-analyses.     

Demonstratives,demonstrations, and demonstrata

I would like to thank Kate Kearns and an anonymous reviewer for helpful comments and suggestions.     

Exercise motivation in university community members: a behavioural intervention

The purpose of this study was to examine how exercise level, exercise motives, and barriers changed from the baseline phase to the follow-up phase after a behavioural and cognitive intervention aimed at increasing exercise. Seventy-five members of our university community (43 subjects in the control group and 32 in the experimental group), all of whom received cognitive feedback, agreed to complete the baseline phase. Only the experimental group received behavioural feedback and a free-access gym ticket with personal training in order to facilitate their adherence to exercise. The results suggest that a combination of behavioural and psychological techniques is an efficient strategy for increasing exercise level. In addition, the results showed that extrinsic motivation predominates the early stages of change-of-exercise behaviour, and that intrinsic motivation is important for progression towards maintenance. Subjects who decreased their exercise level increased their extrinsic exercise motivation and subjects who increased their exercise level decreased the barriers related to intrinsic motivation. These findings indicate that, in order to facilitate exercise adherence, feedback about motives for undertaking exercise is needed, combined with advice about how to improve physical condition. This combination could help eliminate certain barriers that hinder engaging in an active and healthy life-style.     

Kampf um Anerkennung

Violence in partnership is seen as the expression of damaged self-love, discharging in form of narcissistic rage against the other. The disturbed basic emotion about the self as the root of the fight for acceptance in partnerships blurs the boundaries between the partners as independent individuals. The trigger for the acceptance theme in its narcissistic dimension may be jealousy unleashed by unfaithfulness. The wish to be accepted by others is a legitimate need but in its overreaching or denied form it may trigger a spiral of violence, which in its worst forms may lead to fights aimed at extermination.