Ultrasonic tracking of a sinking ball in a vibrated dense granular suspension

Observing and understanding the movement of an intruder through opaque dense suspensions such as quicksand remains a practical and conceptual challenge. Here we use an ultrasonic probe to investigate the dynamics of a steel ball sinking in a 3D dense glass bead packing saturated by water. We show that the frictional model developed for dry granular media can be used to describe the ball motion induced by horizontal vibration. From this rheology we infer the static friction coefficient and effective viscosity that decrease when increasing the vibration intensity. Our main finding is that the vibration-induced reduction of the yield stress and increase of the sinking depth are presumably due to induced slipping at the grain contacts but without visible plastic rearrangements of grains, in contrast to dry granular packings. To explain these results, we propose a mechanism of acoustic lubrication that reduces the inter-particle friction and leads to a decrease of the yield stress. This scenario is different from the mechanism of liquefaction usually invoked in loosely packed quicksands where the vibration-induced compaction increases the pore pressure and decreases the confining pressure on the solid skeleton, thus reducing the granular resistance to external load.Comment: 9 pages and 5 figures, plus the supplemental information (1 page, 2 movies, 1 figure

DOOM'd to Switch: Superior Cognitive Flexibility in Players of First Person Shooter Games

The interest in the influence of videogame experience on our daily life is constantly growing. “First Person Shooter” (FPS) games require players to develop a flexible mindset to rapidly react to fast moving visual and auditory stimuli, and to switch back and forth between different subtasks. This study investigated whether and to which degree experience with such videogames generalizes to other cognitive-control tasks. Video-game players (VGPs) and individuals with little to no videogame experience (NVGPs) performed on a task switching paradigm that provides a relatively well-established diagnostic measure of cognitive flexibility. As predicted, VGPs showed smaller switching costs (i.e., greater cognitive flexibility) than NVGPs. Our findings support the idea that playing FPS games promotes cognitive flexibility

Buddha as an Eye Opener: A Link between Prosocial Attitude and Attentional Control

Increasing evidence suggests that religious practice induces systematic biases in attentional control. We used Navon's global–local task to compare attentional bias in Taiwanese Zen Buddhists and Taiwanese atheists; two groups brought up in the same country and culture and matched with respect to race, intelligence, sex, and age. Given the Buddhist emphasis on compassion for the physical and social environment, we expected a more global bias in Buddhist than in Atheist participants. In line with these expectations, Buddhists showed a larger global-precedence effect and increased interference from global distracters when processing local information. This pattern reinforces the idea that people's attentional processing style reflects biases rewarded by their religious practices

God:Do I have your attention?

Religion is commonly defined as a set of rules, developed as part of a culture. Here we provide evidence that practice in following these rules systematically changes the way people attend to visual stimuli, as indicated by the individual sizes of the global precedence effect (better performance to global than to local features). We show that this effect is significantly reduced in Calvinism, a religion emphasizing individual responsibility, and increased in Catholicism and Judaism, religions emphasizing social solidarity. We also show that this effect is long-lasting (still affecting baptized atheists) and that its size systematically varies as a function of the amount and strictness of religious practices. These findings suggest that religious practice induces particular cognitive-control styles that induce chronic, directional biases in the control of visual attention

Overcoming status quo bias in the human brain

Humans often accept the status quo when faced with conflicting choice alternatives. However, it is unknown how neural pathways connecting cognition with action modulate this status quo acceptance. Here we developed a visual detection task in which subjects tended to favor the default when making difficult, but not easy, decisions. This bias was suboptimal in that more errors were made when the default was accepted. A selective increase in subthalamic nucleus (STN) activity was found when the status quo was rejected in the face of heightened decision difficulty. Analysis of effective connectivity showed that inferior frontal cortex, a region more active for difficult decisions, exerted an enhanced modulatory influence on the STN during switches away from the status quo. These data suggest that the neural circuits required to initiate controlled, nondefault actions are similar to those previously shown to mediate outright response suppression. We conclude that specific prefrontal-basal ganglia dynamics are involved in rejecting the default, a mechanism that may be important in a range of difficult choice scenarios

European consensus on essential steps of Minimally Invasive Ivor Lewis and McKeown Esophagectomy through Delphi methodology

BACKGROUND: Minimally invasive esophagectomy (MIE) is a complex and technically demanding procedure with a long learning curve, which is associated with increased morbidity and mortality. To master MIE, training in essential steps is crucial. Yet, no consensus on essential steps of MIE is available. The aim of this study was to achieve expert consensus on essential steps in Ivor Lewis and McKeown MIE through Delphi methodology. METHODS: Based on expert opinion and peer-reviewed literature, essential steps were defined for Ivor Lewis (IL) and McKeown (McK) MIE. In a round table discussion, experts finalized the lists of steps and an online Delphi questionnaire was sent to an international expert panel (7 European countries) of minimally invasive upper GI surgeons. Based on replies and comments, steps were adjusted and rephrased and sent in iterative fashion until consensus was achieved. RESULTS: Two Delphi rounds were conducted and response rates were 74% (23 out of 31 experts) for the first and 81% (27 out of 33 experts) for the second round. Consensus was achieved on 106 essential steps for both the IL and McK approach. Cronbach’s alpha in the first round was 0.78 (IL) and 0.78 (McK) and in the second round 0.92 (IL) and 0.88 (McK). CONCLUSIONS: Consensus among European experts was achieved on essential surgical steps for both Ivor Lewis and McKeown minimally invasive esophagectomy. SUPPLEMENTARY INFORMATION: The online version of this article (doi:10.1007/s00464-021-08304-5) contains supplementary material, which is available to authorized users

Exposing an “Intangible” Cognitive Skill Among Collegiate Football Players: II. Enhanced Response Impulse Control

American football is played in a dynamic environment that places considerable demands on a player’s ability to make fast, precise reactions while controlling premature, impulsive reactions to spatial misinformation. We investigated the hypothesis that collegiate football players are more proficient than their non-athlete counterparts at controlling impulsive motor actions. National Collegiate Athletic Association (NCAA) Division I football players (n = 280) and non-athlete controls (n = 32) completed a variant of the Simon conflict task, which quantifies choice reaction speed and the proficiency of controlling spatially driven response impulses. Overall, the choice reaction times (RTs) and accuracy rates of football players and controls were equivalent. Similarly, football players and controls were equally susceptible to producing incorrect impulsive motor responses. However, the slowing of RT attributed to the activation and successful inhibition of these impulses (i.e., the Simon effect) was reduced significantly among football players compared to controls. Moreover, differences in impulse control varied by position among the players, with the reduction being greater for offensive than for defensive players. Among offensive players, running backs, wide receivers, and offensive linemen had greater impulse control than did controls, whereas among defensive players only linebackers had greater control. Notably, the Simon effect was reduced by 60% in running backs compared to controls. These results contribute to emerging evidence that elite football players possess more proficient executive control over their motor systems than their age counterparts and suggest that the speed of controlling impulsive motor reactions may represent an enhanced cognitive “intangible” among football players