The generation of complex organ structures such as the eye requires the intricate orchestration of multiple cellular interactions. In this paper, early retinal development is discussed with respect to the structure formation of the optic cup. Although recent studies have elucidated molecular mechanisms of retinal differentiation, little is known about how the unique shape of the optic cup is determined. A recent report has demonstrated that optic‐cup morphogenesis spontaneously occurs in three‐dimensional stem‐cell culture without external forces, indicating a latent intrinsic (...) order to generate the structure. Based on this self‐organizing phenomenon, we introduce the “relaxation‐expansion” model to mechanically interpret the tissue dynamics that enable the spontaneous invagination of the neural retina. This model involves three consecutive local rules (relaxation, apical constriction, and expansion), and its computer simulation recapitulates the optic‐cup morphogenesis in silico. (shrink)

Nelson’s stochastic quantum mechanics provides an ideal arena to test how the Born rule is established from an initial probability distribution that is not identical to the square modulus of the wavefunction. Here, we investigate numerically this problem for three relevant cases: a double-slit interference setup, a harmonic oscillator, and a quantum particle in a uniform gravitational field. For all cases, Nelson’s stochastic trajectories are initially localized at a definite position, thereby violating the Born rule. For the double slit and (...) harmonic oscillator, typical quantum phenomena, such as interferences, always occur well after the establishment of the Born rule. In contrast, for the case of quantum particles free-falling in the gravity field of the Earth, an interference pattern is observed before the completion of the quantum relaxation. This finding may pave the way to experiments able to discriminate standard quantum mechanics, where the Born rule is always satisfied, from Nelson’s theory, for which an early subquantum dynamics may be present before full quantum relaxation has occurred. Although the mechanism through which a quantum particle might violate the Born rule remains unknown to date, we speculate that this may occur during fundamental processes, such as beta decay or particle-antiparticle pair production. (shrink)

Transcription and DNA supercoiling are known to be linked by a cause‐effect relationship that operates in both directions. It is proposed here that this two‐way relationship may be exploited by the E. coli genome to facilitate constitutive transcription of supercoil‐sensitive genes by polymerase batteries made up of uniformly spaced RNA polymerase elongation complexes. Specifically, it is argued that (1) polymerases transcribing DNA in tandem cooperate to relax each other's transcription‐driven positive supercoils; and (2) negative supercoils driven upstream by elongation complexes (...) tend to be ‘harnessed’ and used to cooperatively (and periodically) initiate fresh transcription from promoters. Harnessing of transcription‐driven negative supercoils is thought to be achieved through the erection of protein barriers to the rotational upstream propagation of supercoils from transcription events. The possible relevance of such cooperation amongst polymerases to the activation of transcription by DNA‐binding protein factors is emphasized. Some testable predictions are made and implications are discussed. (shrink)

One of the claims sometimes advanced in favour of anti-doping is that allowing doping would lead to a uniform increase in performance in comparison to no doping. The idea is that if all athletes wo...

IntroductionAn individual’s level of mindfulness can predict his/her level of general health, anxiety, and anger. If we have a valuable tool for measuring mindfulness, we can predict such factors more concisely. Therefore, the aim of this study was to compare a narrowband and a broadband mindfulness scale in predicting the level of general health, anxiety, and anger in a general population.Materials and MethodsThis was a cross-sectional study on an Iranian general population from September 22, 2020 to April 14, 2021. The (...) convenience sampling method was used. Data were collated via electronic and paper forms of the Relaxation/Meditation/Mindfulness Tracker t-Persian version, the Freiburg Mindfulness Inventory- Short-Form-Persian version, the General Health Questionnaire, the trait anxiety section of the State–Trait Anxiety Inventory, and the trait anger section of the State–Trait Anger Expression Inventory-2.ResultsThe FMI-P predicted 0.05% of GHQ variance while the first and third levels of RMMt-P predicted 0.145%. The FMI-P predicted 0.19% of anxiety variance, while the first and third levels of RMMt-P predicted 0.195%. The FMI-P predicted 0.0% of anger variance, while the first, second, and third levels of RMMt-P predicted 0.08%. RMMt-P Level 1 was a better predictor of general health, anger, and anxiety.ConclusionThe current study found that the RMMt-P was a better predictor of general health and anger than the FMI-P. These findings suggest that the type of questionnaire used in the study of mindfulness is important, but more research is needed to determine the extent of these relationships. (shrink)

Cytokinesis in animal cells is accomplished by the active constriction of the equatorial regions of a cell by an actomyosin‐containing contractile ring. The mitotic apparatus specifies the position and orientation of the furrow such that the mitotic spindle is always bisected. Global cortical contractions occur in the cortex of a cell prior to cytokinesis that are independent of the presence of the mitotic apparatus. It was proposed some years ago that the asters of the mitotic apparatus could act to relax (...) the preformed cortical tension in their vicinity. This would produce a differential in tension between the equatorial regions and the adjacent regions of the cortex so that the equatorial regions would contract, forming a cleavage furrow. It can be shown that, as it stands, this theory cannot explain cleavage. However, if cortical contractile elements are assumed to be laterally mobile in the plane of the cortex, then the astral relaxation theory can account for many of the aspects of cleavage, including the formation of the contractile ring. Similar schemes may account for the behaviour of the lamellapodia of motile cells. (shrink)

The quasiclassical theory in terms of Feynman path integrals is used to calculate the decay of the Cooperon amplitude caused by transverse gauge field fluctuations in a disordered electron system. It is found that the phase relaxation rate in two dimensions varies linearly with the temperature as in the more common case of electric field fluctuations, but is proportional to the conductance rather than the resistance. A logarithmic correction factor is found in comparison to an earlier qualitative estimate.

We investigate whether small perturbations can cause relaxation to quantum equilibrium over very long timescales. We consider in particular a two-dimensional harmonic oscillator, which can serve as a model of a field mode on expanding space. We assume an initial wave function with small perturbations to the ground state. We present evidence that the trajectories are highly confined so as to preclude relaxation to equilibrium even over very long timescales. Cosmological implications are briefly discussed.

Growing evidence suggests that natural environments – whether in outdoor or indoor settings – foster psychological health and physiological relaxation, indicated by increased wellbeing, reduced stress levels, and increased parasympathetic activity. Greater insight into differential psychological aspects modulating psychophysiological responses to nature-based relaxation videos could help understand modes of action and develop personalized relaxation interventions. We investigated heart rate variability as an indicator of autonomic regulation, specifically parasympathetic activity, in response to a 10-min video intervention in two consecutive studies as (...) well as heart rate. We hypothesized that a nature-based relaxation video elicits HRV increase and HR decrease, with response magnitude being affected by aspects of early life adversity and trait mindfulness. In Study 1, N = 60 participants watched a relaxation video intervention depicting different natural scenery. We analyzed changes in HR and respiratory sinus arrhythmia as a standard HRV measure, both based on 3-min segments from the experimental session, in multiple growth curve models. We found a decrease in HR and increase of RSA during the video intervention. Higher paternal care and lower trait mindfulness observing skills were associated with higher RSA values before but not during video exposure. In Study 2, N = 90 participants were assigned to three video conditions: natural scenery from Study 1, meditation video, or short clip from “The Lord of the Rings.” Again, HR decreased, and RSA increased during video segments, yet without expected group differences across different video types. We found higher parental care and lower parental overprotection to predict higher RSA at different times during the experiment. Interestingly, lower paternal overprotection predicted overall higher RSA. These results suggest a generic relaxation effect of video interventions on autonomic regulation that we discuss in light of different theories mapping restorative effects of natural environments. Further, psychological characteristics like aspects of early life adversity and trait mindfulness could contribute to individual differences in autonomic regulation. This study contributes to a better understanding of autonomic and psychological responses to relaxation videos. (shrink)

This study aims to investigate whether simple and convenient progressive relaxation training is effective in enhancing collegiate student athletes’ mental health and sports performance. An experimental group of 14 and a control group of 10 collegiate student athletes were recruited from among track and field athletes who were preparing for provincial competition. The experimental group was exposed to a PRT intervention in 30-min sessions conducted twice per week for a duration of one month. At baseline, the Competitive State Anxiety Inventory-2, (...) State-Trait Anxiety Inventory, and Eysenck Personality Questionnaire-Revised Short Scale for Chinese were completed, while only the CSAI-2 was reassessed at one, two, and three weeks after initiation of the intervention. Additionally, within half a day after completing all one’s individual competition events, the CSAI-2 was again assessed in the two groups recalling their memory of their precompetition state anxiety. Then, the differences in the three dimensions of the CSAI-2 between the two groups at the five time points introduced above were compared. This study also explored whether PRT affected sports performance, defined by the athletes reaching their best records or not, by logistic regressive analysis. This study found significant between-group differences in the self-confidence dimension score at the second and third time points. Through logistic regression analysis, a positive effect of PRT was found for the enhancement of sports performance. In sum, PRT showed positive effects on precompetition state self-confidence and enhanced sports performance among collegiate student athletes. (shrink)

Research suggested that developing mindfulness skills in children improves proximal outcomes, such as attention and executive functions, as well as distal outcomes, such as academic achievement. Despite empirical evidence supporting this claim, research on the benefits of mindfulness training in child populations is scarce, with some mixed findings in the field. Here, we aimed to fill in this gap, by examining the effects of a mindfulness training on third graders’ proximal and distal outcomes, namely, attention and executive functions (viz., inhibitory (...) control, working memory, and cognitive flexibility) as well as literacy-related achievement (viz., handwriting fluency, text quality, Portuguese grades). These outcomes were measured with behavioral tasks and teacher ratings. Sixty-six Portuguese children were randomly allocated to an experimental group receiving mindfulness training (n= 29) or an active control group receiving relaxation training (n= 37). Both training programs were implemented by psychologists in two 30-min weekly sessions for 8 weeks. All students were assessed before and after the interventions. Three main findings are noteworthy: (a) mindfulness training enhanced teacher-rated cognitive flexibility and a performance-based composite score of executive functions among children with higher pretest scores; (b) relaxation training improved performance-based cognitive flexibility and the composite score of executive functions among children with lower pretest scores; (c) children receiving mindfulness training had higher handwriting fluency and better grades in Portuguese than those receiving relaxation training. These findings provide preliminary evidence on the benefits of mindfulness training in educational settings and highlight the moderating role of baseline performance on those benefits. (shrink)

Since March 14, 2020, Spain has been in a state of alarm, due to the crisis created by the outbreak of COVID-19. This measure has led to strict levels of lockdown. This situation has led to an increase in anxiety levels among the younger population. For this reason, an intervention was carried out with university voluntary participants in order to help lower their anxiety levels. Specifically, a telematic workshop was implemented to teach emotional literacy and relaxation techniques combined with the (...) practice of the techniques in an autonomous manner. Anxiety measurements were taken before and after the workshop using the GAD7 scale. The results show that Jacobson's progressive relaxation techniques, Schultz's autogenous relaxation, abdominal relaxations and visualizations are effective in lowering the anxiety levels of university students being an alternative to pharmacotherapy. (shrink)

(2013). Multiple paths to transfer and constraint relaxation in insight problem solving. Thinking & Reasoning: Vol. 19, No. 1, pp. 96-136. doi: 10.1080/13546783.2012.742852.

Computerized relaxation training has been suggested as an effective and easily accessible intervention for individuals with psychological distress. To better elucidate the neural mechanism that underpins the effects of relaxation training, we investigated whether a 10-session computerized relaxation training program changed prefrontal gamma-aminobutyric acid levels and cerebral blood flow in women with psychological distress. We specifically focused on women since they were reported to be more vulnerable to develop stress-related disorders than men. Nineteen women with psychological distress but without a (...) diagnosis of psychiatric disorders received the 10-day computerized relaxation training program that consisted of 30-min cognitive-relaxation training and 10-min breathing-relaxation training per day. At baseline and post-intervention, perceived stress levels, anxiety, fatigue, and sleep quality were assessed by self-report questionnaires. Brain magnetic resonance spectroscopy and arterial spin labeling scans were also performed before and after the intervention to evaluate GABA levels and relative CBF in the prefrontal region. Levels of perceived stress, anxiety, fatigue, and sleep quality improved following 10 sessions of computerized relaxation training, resulting in a significant relief in composite scores of stress-related symptoms. The prefrontal GABA levels decreased, while relative CBF increased after the intervention. In addition, a greater increase in relative prefrontal CBF was associated with better composite scores of stress-related symptoms following the intervention. The current findings suggest that computerized relaxation training may improve stress-related symptoms through modulating the prefrontal GABA levels and CBF in women with psychological distress. (shrink)

The search for the best wellness practice has promoted the development of devices integrating different technologies and guided meditation. However, the final effects on the electrical activity of the brain remain relatively sparse. Here, we have analyzed of the alpha and theta electroencephalographic oscillations during the realization of the arrest reaction when a chromotherapy session performed in a dedicated room [Rebalance device], with an ergonomic bed integrating pulsed-wave light stimulation, guided breathing, and body scan exercises. We demonstrated that the PWL (...) induced an evoked-related potential characterized by the N2-P3 components maximally recorded on the fronto-central areas and accompanied by an event-related synchronization of the delta–theta–alpha oscillations. The power of the alpha and theta oscillations was analyzed during repeated ARs testing realized along with the whole RB session. We showed that the power of the alpha and theta oscillations was significantly increased during the session in comparison to their values recorded before. Of the 14 participants, 11 and 6 showed a significant power increase of the alpha and theta oscillations, respectively. These increased powers were not observed in two different control groups who stayed passively outside or inside the RB room but without any type of stimulation. These preliminary results suggest that PWL chromotherapy and guided relaxation induce measurable electrical brain changes that could be beneficial under neuropsychiatric perspectives. (shrink)

Pragmatism is America’s distinctive contribution to the history of philosophical thought, though there has always been some dispute about exactly what doctrine it is supposed to name. The philosopher and psychologist William James, in a lecture given at Berkeley in 1898, attributed the view to..