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The authors consider a game problem of soft meeting of controlled oscillating systems, i.e., their simultaneous convergence in geometric coordinates and velocities. Applying Pontryagin's first direct method [1] to solve this problem is noted to be impossible since the condition underlying this method is not satisfied. This condition is an instantaneous advantage of the pursuer (the one who strives to achieve this meeting) over the evader (the one who tries to avoid it). In the method, we apply the principle of time dilation, which weakens this condition and makes it possible to terminate the game in a finite time. The paper outlines the problem solution method that employs a certain time dilation function. Also, an algorithm, versions of constructing pursuer's control, and an example of computer implementation of the process of convergence on the plane are provided. [ABSTRACT FROM AUTHOR]

The authors propose a method for solving the game problem where the trajectory of a quasi-linear non-stationary system approaches a cylindrical terminal set varying with time. The case is considered where Pontryagin's condition (the condition of the first player's advantage) is not satisfied. A time dilation function is introduced, which postpones the time of game termination and is used to introduce a modified Pontryagin's condition, which allows making a measurable choice of control. The basic method is the method of resolving functions. Using the technique of set-valued mappings and their selectors, the strategies are generated, which guarantee the problem solution. The process of convergence of the trajectory and the terminal set consists of two sections: active and passive, where the control of the first player is selected using the control of the second player with a certain time delay, which depends on the time dilation function. The scheme of the method is outlined and sufficient conditions for the game termination in a finite time are obtained. [ABSTRACT FROM AUTHOR]

For the first time, the possibility of measuring the difference in gravitational potentials and orthometric heights by a quantum level based on the gravitational effect of time dilation using ground communication lines is considered. The duplex mode of measurements using two opposite radio channels is theoretically described. The dilation effect was experimentally measured using a one-way radio communication line implemented based on a fiber-optic link. For measurements, stationary and mobile (transportable) quantum hydrogen clocks were used with relative instabilities of (0.5-0.7)×10-15 and 1×10-15, respectively. It was found that in the experiment, the gravitational redshift of the frequency between the utilized clocks has two components: the redshift of the master oscillator frequency and the classical redshift in the radio channel. Based on the measurement results, the displacement height of the transportable quantum hydrogen clock was calculated to be (–34.0 ± 0.8) m, while the actual height was –34 m. [ABSTRACT FROM AUTHOR]

Our experience of time is strikingly plastic: Depending on contextual factors, the same objective duration can seem to fly by or drag on. Perhaps the most direct demonstration of such subjective time dilation is the oddball effect: when seeing identical objects appear one after another, followed by an "oddball" (e.g., a disc that suddenly grows in size, in a sequence of otherwise static discs), observers experience this oddball as having lasted longer than its nonoddball counterparts. Despite extensive work on this phenomenon, a surprisingly foundational question remains unasked: What actually gets dilated? Beyond the oddball, are the objects just before (or just after) the oddball also dilated? As in previous studies, observers viewed sequences of colored discs, one of which could be the oddball—and subsequently reproduced the oddball's duration. Unlike previous studies, however, there were also critical trials in which observers instead reproduced the duration of the disc immediately before or after the oddball. A clear pattern emerged: oddball-induced time dilation extended to the post-oddball disc, but not the pre-oddball disc. Whence this temporal asymmetry? We suggest that an oddball's sudden appearance may induce uncertainty about what will happen next, heightening attention until after the uncertainty is resolved. [ABSTRACT FROM AUTHOR]

Background: This study aims to compare patency rates of the 0- and 30-s (sec) balloon dilation time in hemodialysis (HD) patients with restenosis after percutaneous transluminal angioplasty (PTA). Methods: The patients who underwent PTA within 6 months for failed arteriovenous fistula at the forearm were randomly assigned the 0-s or 30-s dilation time group. Effect of dilation time on the 3- and 6-month patency rates after PTA was examined. Results: Fifty patients were enrolled in this study. The 3-month patency rate in the 30-s dilation group was better than that in the 0-s dilation group (P = 0.0050), while the 6-month patency rates did not show a significant difference between the two groups (P = 0.28). Cox's proportional hazard model revealed that 30-s of inflation time (hazard ratio 0.027; P = 0.0072), diameter of the proximal (hazard ratio 0.32; P = 0.031), and dilation pressure (hazard ratio 0.63; P = 0.014) were associated with better 3-month patency. Dilation pressure between previous and present PTA did not differ in the 0-s (P = 0.15) and 30-s dilation groups (P = 0.16). The 6-month patency rate of the present PTA in the 30-s dilation group was higher than that of the previous PTA (P = 0.015). The visual analog scale did not differ between the two groups (P = 0.51). Conclusion: The presenting data suggest that 30-s dilation potentially results in a better 3-month patency rate than 0-s dilation in HD patients with restenosis after PTA. [ABSTRACT FROM AUTHOR]

The perceived duration of time does not veridically reflect the physical duration but is distorted by various factors, such as the stimulus magnitude or the observer's emotional state. Here, we showed that knowledge about an event's termination time is another significant factor. We often experience time passage differently when we know that an event will terminate soon. To quantify this, we asked 33 university students to report a rotating clock hand's duration with or without a termination cue that indicated the position at which the clock hand disappeared. The results showed that the presence of the termination cue dilated perceived durations, and the dilating effect was larger when the stimulus duration was longer, or the speed of the rotating stimulus was slower. A control experiment with a start-cue excluded the possibility that the cue's mere existence caused the results. Further computational analyses based on the attention theory-of-time perception revealed that the size of dilation is best explained by neither an event's duration nor the distance traveled by the clock hand, but by how long the clock hand spends time near the termination cue. The results imply that an event-termination cue generates a field in which the perceived time dilates. [ABSTRACT FROM AUTHOR]

Inspired by the recent literature, we study the Einstein–de Sitter cosmological model coupled with a generalization of the relation between the redshift and time dilation of the kind δ t 0 = δ t e (1 + z) n . We find that this model fits the experimental data regarding 1048 supernovae, in a way which is competitive with the standard Λ CDM model and without the need of introducing a non-zero cosmological constant. Since the existence of dark energy, as a main ingredient of the composition of the cosmos, is still under debate, we propose our formalism as an example of an alternative description of the cosmological scenario. [ABSTRACT FROM AUTHOR]

In the real world, object arrangement follows a number of rules. Some of the rules pertain to the spatial relations between objects and scenes (i.e., syntactic rules) and others about the contextual relations (i.e., semantic rules). Research has shown that violation of semantic rules influences interval timing with the duration of scenes containing such violations to be overestimated as compared to scenes with no violations. However, no study has yet investigated whether both semantic and syntactic violations can affect timing in the same way. Furthermore, it is unclear whether the effect of scene violations on timing is due to attentional or other cognitive accounts. Using an oddball paradigm and real-world scenes with or without semantic and syntactic violations, we conducted two experiments on whether time dilation will be obtained in the presence of any type of scene violation and the role of attention in any such effect. Our results from Experiment 1 showed that time dilation indeed occurred in the presence of syntactic violations, while time compression was observed for semantic violations. In Experiment 2, we further investigated whether these estimations were driven by attentional accounts, by utilizing a contrast manipulation of the target objects. The results showed that an increased contrast led to duration overestimation for both semantic and syntactic oddballs. Together, our results indicate that scene violations differentially affect timing due to violation processing differences and, moreover, their effect on timing seems to be sensitive to attentional manipulations such as target contrast. [ABSTRACT FROM AUTHOR]

Field dependence-independence (FDI) is a stable dimension of individual functioning, transversal to different cognitive domains. While the role of some individual variables in time perception has received considerable attention, it is not clear whether and how FDI influences timing abilities. In this study, we tested the hypothesis that FDI differently affects timing performance depending on whether the task requires cognitive restructuring. Participants were assessed for FDI using the embedded figures test (EFT). They performed a prospective timing task, reproducing the duration of a flickering stimulus, and a retrospective timing task, estimating the duration of the task. We expected performance of field-dependent (FD) and field-independent (FI) individuals not to differ in the prospective task, since restructuring of task material is not needed to reproduce the stimulus duration. Conversely, we predicted that FI individuals should be more accurate than FD ones in the retrospective condition, involving restructuring skills. Results show that while both FD and FI individuals under-reproduced the stimulus duration in the prospective task, only FD participants significantly underestimated the duration of the timing task in the retrospective condition. These results suggest that differences across FD and FI individuals are apparent in timing only when the task requires high-level cognitive processing; conversely, these differences do not affect basic sensory processing. [ABSTRACT FROM AUTHOR]

The pulmonary autograft in the Ross procedure, where the aortic valve is replaced by the patient's own pulmonary valve, is prone to failure due to dilatation. This is likely caused by tissue degradation and maladaptation, triggered by the higher experienced mechanical loads in aortic position. In order to further grasp the causes of dilatation, this study presents a model for tissue growth and remodeling of the pulmonary autograft, using the homogenized constrained mixture theory and equations for immuno- and mechano-mediated mass turnover. The model outcomes, compared to experimental data from an animal model of the pulmonary autograft in aortic position, show that inflammation likely plays an important role in the mass turnover of the tissue constituents and therefore in the autograft dilatation over time. We show a better match and prediction of long-term outcomes assuming immuno-mediated mass turnover, and show that there is no linear correlation between the stress-state of the material and mass production. Therefore, not only mechanobiological homeostatic adaption should be taken into account in the development of growth and remodeling models for arterial tissue in similar applications, but also inflammatory processes. [ABSTRACT FROM AUTHOR]

Precise testing of the gravitational time dilation effect suggests comparing the clocks at points with different gravitational potentials. Such a configuration arises when radio frequency standards are installed at orbital and ground stations. The ground-based standard is accessible directly, while the spaceborne one is accessible only via the electromagnetic signal exchange. Reconstructing the current frequency of the spaceborne standard is an ill-posed inverse problem whose solution depends significantly on the characteristics of the stochastic electromagnetic background. The solution for Gaussian noise is known, but the nature of the standards themselves is associated with nonstationary fluctuations of a wide class of distributions. A solution is proposed for a background of flicker fluctuations with a spectrum (1/ f), where 1 < γ < 3, and stationary increments. The results include formulas for the error in reconstructing the frequency of the spaceborne standard and numerical estimates for the accuracy of measuring the relativistic redshift effect. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of vitamin D deficiency on pupillary responses in the pediatric population. Methods: The study was conducted using data from the right eyes of 52 children with vitamin D deficiency and 52 healthy children. Measurements were taken under static and dynamic conditions with automatic pupillometry. Static measurements were performed at scotopic, mesopic, and photopic light intensities. The mean pupil dilation speed was calculated by observing the changes in pupil dilation over time according to dynamic measurements. Differences between patient and control groups were analyzed for the static and dynamic measurements and the mean pupil dilation speed. Results: While the two groups were similar in terms of scotopic, mesopic, the first dynamic measurements, and the pupil dilation speed data (p > 0.05), a significant difference was found in the photopic conditions (p = 0.001). The mean pupil diameter of the patient group was 4.46 ± 0.928 mm and 3.95 ± 0.556 mm in the control group under photopic conditions. Conclusions: Pediatric patients with vitamin D deficiency have significantly larger pupil diameters in photopic conditions than healthy children. These results suggest that there is an autonomic dysfunction in vitamin D deficiency in the pediatric population, especially pointing to the parasympathetic system. [ABSTRACT FROM AUTHOR]

The well-known experiments performed by Pound and Rebka already in the 1960s confirmed the effect of gravitational time dilation, which had been predicted earlier within the framework of the general relativity theory. However, since photon exchange occurred in the course of these experiments on comparing the frequencies of nuclear resonance fluorescence at various altitudes, the reasons underlying the origin of this effect are explained in the literature by two different and, in fact, alternative presumed physical phenomena. According to the first explanation, clocks locate higher run faster, which is due to an increase in the gravitational potential with increasing distance from the Earth, whereas ascending and descending photons do not change their frequency (by the same clock, e.g., that of the so-called outside observer). According to the second explanation, the clock rate is the same at different altitudes, but the ascending photons undergo a redshift since they lose their energy, while the descending photons undergo a blueshift since they acquire energy. Other combined interpretations of the gravitational time dilation, which presume that the both phenomena exist simultaneously, are proposed in the literature. We propose an experiment with two clocks being active hydrogen masers, one of which is located at the bottom of a high-rise building, and the other, on the top of the building. In this case, time is measured by the first and second clocks during a sufficiently long time interval. After that, the masers are placed at one point, and their indications are compared. In this case, the photon exchange is not required for comparison of the clock readings, and, therefore, the method proposed allows one to reveal the actual reason of the effect under consideration. Numerical estimations are made, which allow for the accompanying effects influencing the measurement accuracy. Critical analysis of the earlier experiments shows that they are either equivocal, or are not absolutely impeccable from the methodology viewpoint. [ABSTRACT FROM AUTHOR]

Background: Controlled radial expansion (CRE) balloon dilators are traditionally used to dilate esophageal strictures during an esophagogastroduodenoscopy (EGD). EndoFLIP is a diagnostic tool used during an EGD to measure important parameters of the gastrointestinal lumen, capable of assessing treatment before and after dilation. EsoFLIP is a related device that combines a balloon dilator with high-resolution impedance planimetry to provide some of the luminal parameters in real time during dilation. We sought to compare procedure time, fluoroscopy time, and safety profile of esophageal dilation using either CRE balloon dilation combined with EndoFLIP (E + CRE) versus EsoFLIP alone. Methods: A single-center retrospective review was performed to identify patients ≤ 21 years of age who underwent an EGD with biopsy and esophageal stricture dilation using E + CRE or EsoFLIP between October 2017 and May 2022. Results: Twenty-nine EGDs with esophageal stricture dilation were performed in 23 patients (19 E + CRE and 10 EsoFLIP). The two groups did not differ in age, gender, race, chief complaint, type of esophageal stricture, or history of prior gastrointestinal procedures (all p > 0.05). The most common medical history in the E + CRE and EsoFLIP groups were eosinophilic esophagitis and epidermolysis bullosa, respectively. Median procedures times were shorter in the EsoFLIP cohort compared to E + CRE balloon dilation (40.5 min [IQR 23–57 min] for the EsoFLIP group; 64 min [IQR 51–77 min] for the E + CRE group; p < 0.01). Median fluoroscopy times were also shorter for patients who underwent EsoFLIP (0.16 min [IQR 0–0.30 min] for EsoFLIP dilation; 0.30 min [IQR 0.23–0.55] for the E + CRE group; p = 0.003). There were no complications or unplanned hospitalizations in either group. Conclusion: EsoFLIP dilation of esophageal strictures was faster and required less fluoroscopy than CRE balloon dilation combined with EndoFLIP in children, while being equally as safe. Prospective studies are needed to further compare the two modalities. [ABSTRACT FROM AUTHOR]

The physics of low-energy quantum systems is usually studied without explicit consideration of the background spacetime. Phenomena inherent to quantum theory in curved spacetime, such as Hawking radiation, are typically assumed to be relevant only for extreme physical conditions: at high energies and in strong gravitational fields. Here we consider low-energy quantum mechanics in the presence of gravitational time dilation and show that the latter leads to the decoherence of quantum superpositions. Time dilation induces a universal coupling between the internal degrees of freedom and the centre of mass of a composite particle. The resulting correlations lead to decoherence in the particle position, even without any external environment. We also show that the weak time dilation on Earth is already sufficient to affect micrometre-scale objects. Gravity can therefore account for the emergence of classicality and this effect could in principle be tested in future matter-wave experiments. [ABSTRACT FROM AUTHOR]

Time dilation was experienced in most countries and across the several years of the Covid-19 crisis: the passage of time was deemed slower than before the pandemic, and the distance to the beginning of the pandemic seemed longer than it really was. An outstanding question is how these two aspects of time judgements relate to other temporal, social and affective disturbances. We developed and validated a 59-item questionnaire to explore these questions. 3306 participants completed the questionnaire in France in May and June 2021. Here, we analyse group differences and find that both slow passage of time and long distance judgements were associated with larger disturbances across all domains under study. These included temporal disruptions—the aptness to project oneself into the future, the sense of a rift between pre-pandemic and pandemic time, the ability to locate oneself in time, the capacity to recall the order of past events—, as well as an overall sense of social disorientation, and trauma-specific disturbances. In contrast, both fast passage of time and short distance judgements were associated with beneficial effects across all of the mentioned domains. Our results indicate that perceived passage of time and temporal distance judgements are key indicators of social and temporal disorientation. [ABSTRACT FROM AUTHOR]

We investigated whether Early Posterior Negativity (EPN) indicated the subjective dilation of time when judging the duration of arousing stimuli. Participants performed a visual temporal bisection task along with high-level and low-level arousing auditory stimuli, while we simultaneously recorded EEG. In accordance with previous studies, arousing stimuli were temporally overestimated and led to higher EPN amplitude. Yet, we observed that time dilation and EPN amplitude were significantly correlated and this effect cannot be explained by confounds from stimulus valence. We interpret our findings in terms of the pacemaker–accumulator model of human timing, and suggest that EPN indicates an arousal-based increasing of the speed of our mental clock. [ABSTRACT FROM AUTHOR]

Compared to a stationary pattern, a moving pattern dilates the perception of time. However, when it comes to comparing only moving stimulus, the exact dilation effects are less clear. The time dilation may be attributed to either speed of motion, temporal and spatial frequency, stimulus complexity, or the number of changes in the stimulus pattern. In the present study, we used progress bars and throbbers for inducing impressions of fast and slow "apparent" motions while the speed of motion and distance covered was actually equivalent across all conditions. The results indicate that higher number of steps produced the impression of a faster progression leading to an underestimation of time, whereas a progression in large fewer steps, produced slower apparent progression, creating the illusion of dilated time. We suggest that the perception of time depends on the nature of the stimulus rather than the speed of motion or the distance covered by the stimulus. [ABSTRACT FROM AUTHOR]

The current theories of quantum physics and general relativity on their own do not allow us to study situations in which the gravitational source is quantum. Here, we propose a strategy to determine the dynamics of objects in the presence of mass configurations in superposition, and hence an indefinite spacetime metric, using quantum reference frame (QRF) transformations. Specifically, we show that, as long as the mass configurations in the different branches are related via relative-distance-preserving transformations, one can use an extension of the current framework of QRFs to change to a frame in which the mass configuration becomes definite. Assuming covariance of dynamical laws under quantum coordinate transformations, this allows to use known physics to determine the dynamics. We apply this procedure to find the motion of a probe particle and the behavior of clocks near the mass configuration, and thus find the time dilation caused by a gravitating object in superposition. Comparison with other models shows that semi-classical gravity and gravitational collapse models do not obey the covariance of dynamical laws under quantum coordinate transformations. Finding a way to combine quantum mechanics and gravity is a longstanding issue in physics. While there are different approaches to quantum gravity, there are many challenges in making concrete predictions for scenarios at the interface of these two theories. Here, the authors propose a first-principles strategy to determine the dynamics of objects in the presence of mass configurations in superposition, which enables predictions where the gravitational source is in a quantum superposition rather than a classical configuration. [ABSTRACT FROM AUTHOR]

In the present study, we investigated how the perception of auditory duration could be modulated by a task-irrelevant, concurrent visual apparent motion, induced by visual bars alternating between left and right sides. Moreover, we examined the influence of the speed and temporal frequency of visual apparent motion on the perception of auditory duration. In each trial, the standard visual stimuli (two vertical bars) were presented sequentially, except that visual apparent motion was included in the fourth stimulus. A tone was presented simultaneously with each visual stimulus, while the fourth tone was presented with varied duration. Participants judged whether the fourth tone lasted longer than the other four tones. In Experiment 1, the speed of visual apparent motion (Fast vs. Slow) was manipulated by changing the interval between two bars. The mean point of subjective equality (PSE) in the Slow apparent motion condition was larger than that in the Static condition. Moreover, participants tended to overestimate the duration only in the Static condition, i.e., time dilation effect, which disappeared under apparent motion conditions. In Experiment 2, in addition to speed, we controlled the temporal frequency of apparent motion by manipulating the number of bars, generating four conditions of visual apparent motion (Physical-fast, Perceived-fast, Perceived-slow, vs. Static). The mean PSE was significantly smaller in the Physical-fast condition than in the Static and Perceived-slow conditions. Moreover, we found a time compression effect in both the Perceived-slow and Static conditions but not in the Perceived-fast and Physical-fast conditions. These results suggest that the auditory duration could be modulated by the concurrent, contextual visual apparent motion, and both the speed and temporal frequency of the task-irrelevant visual apparent motion contribute to the bias in perceiving the auditory duration. [ABSTRACT FROM AUTHOR]

Time dilation is one of the most fascinating aspects of special relativity as it abolishes the notion of absolute time. It was first observed experimentally by Ives and Stilwell in 1938 using the Doppler effect. Here we report on a method, based on fast optical atomic clocks with large, but different Lorentz boosts, that tests relativistic time dilation with unprecedented precision. The approach combines ion storage and cooling with optical frequency counting using a frequency comb. 7Li+ ions are prepared at 6.4% and 3.0% of the speed of light in a storage ring, and their time is read with an accuracy of 2×10−10 using laser saturation spectroscopy. The comparison of the Doppler shifts yields a time dilation measurement represented by a Mansouri–Sexl parameter , consistent with special relativity. This constrains the existence of a preferred cosmological reference frame and CPT- and Lorentz-violating ‘new’ physics beyond the standard model. [ABSTRACT FROM AUTHOR]

The perceived duration of a target visual stimulus is shorter when a brief non-target visual stimulus precedes and trails the target than when it appears alone. This time compression requires spatiotemporal proximity of the target and non-target stimuli, which is one of the perceptual grouping rules. The present study examined whether and how another grouping rule, stimulus (dis)similarity, modulated this effect. In Experiment 1, time compression occurred only when the preceding and trailing stimuli (black–white checkerboard) were dissimilar from the target (unfilled round or triangle) with spatiotemporal proximity. In contrast, it was reduced when the preceding or trailing stimuli (filled rounds or triangles) were similar to the target. Experiment 2 revealed time compression with dissimilar stimuli, independent of the intensity or saliency of the target and non-target stimuli. Experiment 3 replicated the findings of Experiment 1 by manipulating the luminance similarity between target and non-target stimuli. Furthermore, time dilation occurred when the non-target stimuli were indistinguishable from the target stimuli. These results indicate that stimulus dissimilarity with spatiotemporal proximity induces time compression, whereas stimulus similarity with spatiotemporal proximity does not. These findings were discussed in relation to the neural readout model. [ABSTRACT FROM AUTHOR]

To study the feasibility and safety of One-Shot Dilatation (OSD), versus serial sequential dilatation in tubeless Percutaneous Nephrolithotomy (PCNL). One Hundred and Fifty patients were randomised into two groups; Group A (One-Shot Dilatation), Group B (Serial Dilatation). Twenty-one patients were excluded from the study. Detailed history was taken and full physical examination was performed. Pre-operative routine laboratory investigations were done. Also, non-contrast Computed Tomography of the Urinary Tract (CTUT) and plain urinary tract x-ray were done. Intra-operative assessments of dilatation, total operative, total fluoroscopy and fluoroscopy during dilatation durations were recorded, as well as estimated blood loss. Post-operatively haemoglobin, creatinine levels and CTUT were performed for all patients. Complications, as urinary leakage time, analgesic requirements and hospitalization time were measured. There were statistically significant differences in the intraoperative durations, where Group A had shorter dilatation time, fluoroscopy time during dilatation and total operative time. Group B had a higher complications rate than Group A; 37.9%, 11.3%, respectively. Also, Group B showed haemoglobin drop by 0.44 mg/dl higher than Group A. More doses of analgesia were required for Group B. Hospitalization time and rate of urinary leakage were both in favour of Group A. For patients undergoing Tubeless PCNL, we have concluded that one-shot dilatation seems to be a safer and more feasible technique than Serial dilatation. [ABSTRACT FROM AUTHOR]

We present results on a ground-based experiment to measure the gravitational effect of a shift in the timescale of stationary and transportable hydrogen quantum clocks. It is proposed to use a transportable highly stable quantum clock to measure the difference at orthometric heights. [ABSTRACT FROM AUTHOR]

We present a general relativistic model of a spherical shell of matter with a perfect fluid on its surface coupled to an internal oscillator, which generalizes a model recently introduced by the authors to construct a self-gravitating interferometer (Gooding and Unruh in Phys Rev D 90:044071, ). The internal oscillator evolution is defined with respect to the local proper time of the shell, allowing the oscillator to serve as a local clock that ticks differently depending on the shell's position and momentum. A Hamiltonian reduction is performed on the system, and an approximate quantum description is given to the reduced phase space. If we focus only on the external dynamics, we must trace out the clock degree of freedom, and this results in a form of intrinsic decoherence that shares some features with a proposed 'universal' decoherence mechanism attributed to gravitational time dilation (Pikovski et al in Nat Phys, ). We note that the proposed decoherence remains present in the (gravity-free) limit of flat spacetime, emphasizing that the effect can be attributed entirely to proper time differences, and thus is not necessarily related to gravity. Whereas the effect described in (Pikovski et al in Nat Phys, ) vanishes in the absence of an external gravitational field, our approach bootstraps the gravitational contribution to the time dilation decoherence by including self-interaction, yielding a fundamentally gravitational intrinsic decoherence effect. [ABSTRACT FROM AUTHOR]

A new wave of relativistic nature is derived from the classical Hamilton-Jacobi equation on a curved space-time. The gravitational time dilation in the neighbourhood of an almost point-like mass is responsible for its existence. In order to obtain such type of wave (interpretable as a matter field), one has to resort to an old idea due to de Broglie according to which the physical 3 -dimensional space behaves as if it were covered with an infinity of clocks. The resulting particle field, that propagates in the physical 3 -dimensional space and is due to the interaction with the (classic) gravitational field of the mass, is shown to be associated with the usual scalar particle wave function of quantum mechanics. Therefore, the model here described, by linking Einstein’s general relativity to the wave-like behaviour of particles via the viewpoint of de Broglie’s Double Solution Theory rather than via the standard mechanisms of field quantisation, provides a new approach to quantum gravity. Finally, it is shown that this model provides a new interpretation of the single-particle interference and explains non-locality in terms of a novel quantum communication channel. [ABSTRACT FROM AUTHOR]

Sensing the passage of time is important for countless daily tasks, yet time perception is easily influenced by perception, cognition, and emotion. Mechanistic accounts of time perception have traditionally regarded time perception as part of central cognition. Since proprioception, action execution, and sensorimotor contingencies also affect time perception, perception-action integration theories suggest motor processes are central to the experience of the passage of time. We investigated whether sensory information and motor activity may interactively affect the perception of the passage of time. Two prospective timing tasks involved timing a visual stimulus display conveying optical flow at increasing or decreasing velocity. While doing the timing tasks, participants were instructed to imagine themselves moving at increasing or decreasing speed, independently of the optical flow. In the direct-estimation task, the duration of the visual display was explicitly judged in seconds while in the motor-timing task, participants were asked to keep a constant pace of tapping. The direct-estimation task showed imagining accelerating movement resulted in relative overestimation of time, or time dilation, while decelerating movement elicited relative underestimation, or time compression. In the motor-timing task, imagined accelerating movement also accelerated tapping speed, replicating the time-dilation effect. The experiments show imagined movement affects time perception, suggesting a causal role of simulated motor activity. We argue that imagined movements and optical flow are integrated by temporal unfolding of sensorimotor contingencies. Consequently, as physical time is relative to spatial motion, so too is perception of time relative to imaginary motion. [ABSTRACT FROM AUTHOR]

A communication scenario is described involving a series of events triggered by a transmitter and observed by a receiver experiencing relativistic time dilation. The message selected by the transmitter is assumed to be encoded in the events' timings and is required to be perfectly recovered by the receiver, regardless of the difference in clock rates in the two frames of reference. It is shown that the largest proportion of the space of all k-event signals that can be selected as a code ensuring error-free information transfer in this setting equals ζ(k)−1, where ζ is the Riemann zeta function. [ABSTRACT FROM AUTHOR]

Deformed relativistic kinematics is a framework which captures effects, that are expected from particles and fields propagating on a quantum spacetime, effectively. They are formulated in terms of a modified dispersion relation and a modified momentum conservation equation. In this work we use Finsler geometry to formulate deformed relativistic kinematics in terms of particle velocities. The relation between the Finsler geometric velocity dependent formulation and the original momentum dependent formulation allows us to construct deformed Lorentz transformations between arbitrary frames. Moreover, we find the corresponding compatible momentum conservation equation to first order in the Planck scale deformation of special relativity based on the κ-Poincaré algebra in the bicrossproduct basis. We find that the deformed Lorentz transformations, as well as the deformed time dilation factor, contain terms that scale with the energy of the particle under consideration to the fourth power. We derive how the distributions of decay products are affected when the deformed relativity principle is satisfied and find, for the case of a pion decaying into a neutrino and a muon, that the ratio of expected neutrinos to muons with a certain energy is just slightly modified when compared to the predictions based on special relativity. We also discuss the phenomenological consequences of this framework for cosmic-ray showers in the atmosphere. [ABSTRACT FROM AUTHOR]

Considers time dilation as a cause of elasticity of the effective Riemannian space. Relation of the cause of space elasticity to an effect of the space curvature on the quantum fluctuations of physical fields; Use of Riemannian space within the framework of general relativity theory as a basis space; Determination of metric tensor.

Background: Benign esophageal strictures are a frequent complication after esophageal surgery or extensive endoscopic submucosal dissection. Endoscopic dilation is the preferred treatment in clinical practice. However, the allocation of time for each dilation is unclear. The aim of this study was to evaluate the appropriate duration of endoscopic dilation for benign esophageal strictures after esophageal surgery or endoscopic submucosal dissection. Methods: Patients with benign esophageal strictures after esophageal surgery or endoscopic submucosal dissection between July 2010 and July 2018 were retrospectively included in this study. According to the dilation time (1, 3, 5 min), patients were divided into three groups. The clinical effects and adverse events were compared among the three groups. Results: Altogether, 57 patients, including 21 in the 1-min group, 18 in the 3-min group and 18 in the 5-min group, were included. All patients underwent endoscopic treatment successfully. The stricture recurrence rate was 76.19% in the 1-min group, 55.56% in the 3-min group and 61.11% in the 5-min group. The median overall dysphagia-free period was 2.60 (range, 0.80–12.00) months in the 1-min group, 6.60 (range, 1.80–12.00) months in the 3-min group and 6.25 (range, 2.40–12.00) months in the 5-min group (P < 0.05). For patients who developed stricture recurrence, the mean dysphagia-free periods were 2.26 ± 1.27 months, 4.00 ± 1.76 months and 4.23 ± 1.63 months, respectively (P < 0.05). The dysphagia-free periods were comparable between the 3- and 5-min groups and were longer than those in the 1-min group. Muscle layer damage occurred in two patients (11.11%) in the 5-min group and in no patients in the other two groups. Conclusion: Three minutes was considered a safe and effective dilation duration for benign esophageal strictures after esophageal surgery or endoscopic submucosal dissection. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to examine the performance of binocular chromatic pupillometry for the objective and rapid detection of primary open-angle glaucoma (POAG), and to explore the association between pupillary light response (PLR) features and structural glaucomatous macular damage. Methods: Forty-six patients (mean age 41.00 ± 13.03 years) with POAG and 23 healthy controls (mean age 42.00 ± 11.08 years) were enrolled. All participants underwent sequenced PLR tests of full-field, superior/inferior quadrant-field chromatic stimuli using a binocular head-mounted pupillometer. The constricting amplitude, velocity, and time to max constriction/dilation, and the post-illumination pupil response (PIPR) were analyzed. The inner retina thickness and volume measurements were determined by spectral domain optical coherence tomography. Results: In the full-field stimulus experiment, time to pupil dilation was inversely correlated with perifoveal thickness (r = − 0.429, P < 0.001) and perifoveal volume (r = − 0.364, P < 0.001). Dilation time (AUC 0.833) showed good diagnostic performance, followed by the constriction amplitude (AUC 0.681) and PIPR (AUC 0.620). In the superior quadrant-field stimulus experiment, time of pupil dilation negatively correlated with inferior perifoveal thickness (r = − 0.451, P < 0.001) and inferior perifoveal volume (r = − 0.417, P < 0.001). The dilation time in response to the superior quadrant-field stimulus showed the best diagnostic performance (AUC 0.909). In the inferior quadrant-field stimulus experiment, time to pupil dilation (P < 0.001) correlated well with superior perifoveal thickness (r = − 0.299, P < 0.001) and superior perifoveal volume (r = − 0.304, P < 0.001). Conclusion: The use of chromatic pupillometry offers a patient-friendly and objective approach to detect POAG, while the impairment of PLR features may serve as a potential indicator of structural macular damage. [ABSTRACT FROM AUTHOR]

Background: The magnetic sphincter augmentation device (MSA) provides effective relief of gastroesophageal reflux symptoms. Dysphagia after MSA implantation sometimes prompts endoscopic dilation. The manufacturer's instructions are that it be performed 6 or more weeks after implantation under fluoroscopic guidance to not more than 15 mm keeping 3 or more beads closed. The purpose of this study was to assess adherence to these recommendations and explore the techniques used and outcomes after MSA dilation. Methods and procedures: We conducted a multicenter retrospective review of patients undergoing dilation for dysphagia after MSA placement from 2012 to 2018. Results: A total of 144 patients underwent 245 dilations. The median size of MSA placed was 14 beads (range 12–17) and the median time to dilation was 175 days. A second dilation was performed in 67 patients, 22 patients had a third dilation and 7 patients underwent 4 or more dilations. In total, 17 devices (11.8%) were eventually explanted. The majority of dilations were performed with a balloon dilator (81%). The median dilator size was 18 mm and 73.4% were done with a dilator larger than 15 mm. There was no association between dilator size and need for subsequent dilation. Fluoroscopy was used in 28% of cases. There were no perforations or device erosions related to dilation. Discussion: There is no clinical credence to the manufacturer's recommendation for the use of fluoroscopy and limitation to 15 mm when dilating a patient for dysphagia after MSA implantation. Use of a larger size dilator was not associated with perforation or device erosion, but also did not reduce the need for repeat dilation. Given this, we would recommend that the initial dilation for any size MSA device be done using a 15 mm through-the-scope balloon dilator. Dysphagia prompting dilation after MSA implantation is associated with nearly a 12% risk of device explantation. [ABSTRACT FROM AUTHOR]

What would the universe be like if we would give up the principle of equivalence and as a consequence incorporate gravity on a more traditional interaction basis within the theory of special relativity? The current work proposes such a gravitational model where a new law of gravitation is expressed in a Lorentz invariant form and is simultaneously in great agreement with many observations (including general relativity). We find the following predictions so far to be consistent with observations: (1) precession formulas explaining, for example, the Mercury apsidal precession, (2) gravitational bending of light near the limb of a massive object, (3) gravitational redshift, (4) escape velocity near a black hole, (5) several relativistic orbit details are derived in the strong field regime and found to be consistent with GR and also the observed shadow of the M87 black hole. Curved space effects such as gravitational time dilation or Shapiro delay cannot be explained within the realms of special relativity (Sect. 3.11). [ABSTRACT FROM AUTHOR]

In this paper, we study the phenomenon of quantum interference in the presence of external gravitational fields described by alternative theories of gravity. We analyze both non-relativistic and relativistic effects induced by the underlying curved background on a superposed quantum system. In the non-relativistic regime, it is possible to come across a gravitational counterpart of the Bohm–Aharonov effect, which results in a phase shift proportional to the derivative of the modified Newtonian potential. On the other hand, beyond the Newtonian approximation, the relativistic nature of gravity plays a crucial rôle. Indeed, the existence of a gravitational time dilation between the two arms of the interferometer causes a loss of coherence that is in principle observable in quantum interference patterns. We work in the context of generalized quadratic theories of gravity to compare their physical predictions with the analogous outcomes in general relativity. In so doing, we show that the decoherence rate strongly depends on the gravitational model under investigation, which means that this approach turns out to be a promising test bench to probe and discriminate among all the extensions of Einstein's theory in future experiments. [ABSTRACT FROM AUTHOR]

To embrace the special theory of relativity with classical thermodynamics correct Lorentz transformations of thermodynamic state functions are formulated. All of these Lorentz transformations of state functions equally support the time dilation phenomenon which is an experimentally verified fact. Relativistic Boltzmann constant proves entropy to be the Lorentz variant. Twin paradox thought experiments for heat engines prove heat flux to be Lorentz variant. Lorentz transformation of entropy and heat flux proves temperature Lorentz invariant. All thermodynamic state functions are proved to be Lorentz variant which is shown in accord with Lorentz transformation of thermodynamic work. [ABSTRACT FROM AUTHOR]

The frequency measurement of Doppler-shifted optical lines of ions circulating in a storage ring at high speed permits a sensitive test of the relativistic Doppler-formula and, hence, the time dilation factor γSR of special relativity. Previous measurements at the storage ring TSR with 7Li+ at v=0.065c gave a new, improved limit, but were hampered by the large observed linewidth, exceeding the natural width 15-fold. Recently we have identified the broadening to be caused by velocity-changing processes in the storage ring. Saturation spectroscopy has proven to be largely immune against these effects and has yielded linewidths only a few MHz larger than the natural one. This is the major ingredient for an improved test of γSR, which is now under way. [ABSTRACT FROM AUTHOR]

Concentrations of the hormone leptin, which is produced by adipose tissue, increase with increasing BMI, whereas leptin sensitivity often declines with higher BMI. Thus, altered leptin signaling may play a role in reproductive health risks observed with increasing BMI, which include later onset and slow progression of labor. Conflicting evidence from clinical, animal and in vitro studies have suggested that leptin either promotes or inhibits labor. We hypothesized that serum leptin concentrations or serum leptin: body mass index (BMI) ratios in women may be associated with the initiation and progression of labor. Following informed consent, serum samples were collected from 90 women with singleton pregnancies at the time of routine glucose-challenge testing, for measurement of leptin. The potential influence of leptin on gestation length and cervical dilation timing were examined by multiple linear regression. Data were analyzed from 63 participants who met exclusion and inclusion criteria. Leptin concentrations (log-transformed) at 24–28 weeks gestation were not significantly correlated with first trimester BMI. Log serum leptin and leptin: BMI ratio each were significantly associated with shorter total gestation length in uncomplicated, term pregnancies. In contrast, the mid-pregnancy leptin concentrations were not associated with progression of labor, assessed by cervical dilation over time. The association between higher serum leptin and shorter gestation length is consistent with the hypothesis that leptin promotes, or is permissive for, the onset of labor. [ABSTRACT FROM AUTHOR]

At the intersection of quantum theory and relativity lies the possibility of a clock experiencing a superposition of proper times. We consider quantum clocks constructed from the internal degrees of relativistic particles that move through curved spacetime. The probability that one clock reads a given proper time conditioned on another clock reading a different proper time is derived. From this conditional probability distribution, it is shown that when the center-of-mass of these clocks move in localized momentum wave packets they observe classical time dilation. We then illustrate a quantum correction to the time dilation observed by a clock moving in a superposition of localized momentum wave packets that has the potential to be observed in experiment. The Helstrom-Holevo lower bound is used to derive a proper time-energy/mass uncertainty relation. The usual definition of external time is unlikely to survive if we want to unite quantum mechanics and relativity. Here the authors consider two quantum clocks moving in curved spacetime and formulate the probability distribution that relates their proper times, allowing them to explore quantum time dilation. [ABSTRACT FROM AUTHOR]

In this article, we want to analyze a relativistic paradox in a very simple way, which, in our opinion, could be useful for a pedagogical purpose. Indeed we want to solve it using only Einstein's relativity principle and the Einstein equivalence principle. We think it could be useful from a pedagogical point of view. [ABSTRACT FROM AUTHOR]

This paper presents a novel speaking-aid system for enhancing esophageal speech (ES). The method adopted in this paper aims to improve the quality of esophageal speech using a combination of a voice conversion technique and a time dilation algorithm. In the proposed system, a Deep Neural Network (DNN) is used as a nonlinear mapping function for vocal tract vector transformation. Then the converted frames are used to determine realistic excitation and phase vectors from the target training space using a frame selection algorithm. Next, in order to preserve speaker identity of the esophageal speakers, we use the source vocal tract features and propose to apply on them a time dilation algorithm to reduce the unpleasant esophageal noises. Finally the converted speech is reconstructed using the dilated source vocal tract frames and the predicted excitation and phase. DNN and Gaussian mixture model (GMM) based voice conversion systems have been evaluated using objective and subjective measures. Such an experimental study has been realized also in order to evaluate the changes in speech quality and intelligibility of the transformed signals. Experimental results demonstrate that the proposed methods provide considerable improvement in intelligibility and naturalness of the converted esophageal speech. [ABSTRACT FROM AUTHOR]

The present study examined whether implicit motion information from static images influences perceived duration of image presentation. In Experiments 1 and 2, we presented observers with images of a human and an animal character in running and standing postures. The results revealed that the perceived presentation duration of running images was longer than that of standing images. In Experiments 3 and 4, we used abstract block-like images that imitated the human figures used in Experiment 1, presented with different instructions to change the observers' interpretations of the stimuli. We found that the perceived duration of the block image presented as a man running was longer than that of the image presented as a man standing still. However, this effect diminished when the participants were told the images were green onions (objects with no implied motion), suggesting that the effect of implied motion cannot be attributed to low-level visual differences. These results suggest that implied motion increases the perceived duration of image presentation. The potential involvement of higher-order motion processing and the mirror neuron system is discussed. [ABSTRACT FROM AUTHOR]

The important role played by some thought experiments in the development of physics has been brought out by expatiating Maxwell’s demon, time dilation, length contraction, twin paradox, Heisenberg’s microscope and Einstein-Bohr box. [ABSTRACT FROM AUTHOR]

We shown that the internal Schwarzschild-type solution in the field theory of gravity does not lead to infinite pressure inside the body as is the case in general relativity. This occurs as a result of the graviton rest mass because the time-dilation process terminates. [ABSTRACT FROM AUTHOR]

It has been suggested that the interference in the Stroop task arises due to both information conflict (color vs. word meaning) and task conflict (respond to the color vs. read the word). Interestingly, the task conflict (faster responses in the congruent condition compared to the neutral condition) is influenced by the readability of the stimulus. However, behavioral results indicate the influence of the contribution of readability to the task conflict appears only when vocal responses are required. We conducted a Stroop experiment with four readability levels of neutrals. Participants were required to respond manually, and both their response times and pupil dilation were measured. Our results showed the slowest responses for incongruent trials and the fastest responses for congruent trials. However, no differences in responses were found between the readability levels of the neutrals. In contrast, pupil dilation showed the largest dilation in the incongruent trials and smallest dilation in the neutral trials. In addition, the differences between congruent and neutral trials were influenced by the readability of the stimulus. Specifically, unreadable neutral stimuli showed meaningful differences early on, which also remained for longer time compared with readable neutral stimuli. These results are important and can help in specifying new requirements regarding the theory and modeling of the Stroop task; in particular, studies that want to control the neutrality of their neutral trials should take the readability into account. [ABSTRACT FROM AUTHOR]

APOBEC mutagenesis, a major driver of cancer evolution, is known for targeting TpC sites in DNA. Recently, we showed that APOBEC3A (A3A) targets DNA hairpin loops. Here, we show that DNA secondary structure is in fact an orthogonal influence on A3A substrate optimality and, surprisingly, can override the TpC sequence preference. VpC (non-TpC) sites in optimal hairpins can outperform TpC sites as mutational hotspots. This expanded understanding of APOBEC mutagenesis illuminates the genomic Twin Paradox, a puzzling pattern of closely spaced mutation hotspots in cancer genomes, in which one is a canonical TpC site but the other is a VpC site, and double mutants are seen only in trans, suggesting a two-hit driver event. Our results clarify this paradox, revealing that both hotspots in these twins are optimal A3A substrates. Our findings reshape the notion of a mutation signature, highlighting the additive roles played by DNA sequence and DNA structure. [ABSTRACT FROM AUTHOR]

An algorithm is presented for solving the lost-in-space problem using simultaneous observations of X-ray pulsars. Using a norm-minimization-based approach, the algorithm extends a previous banded-error intersection model to 3-dimensional space. Higher-fidelity X-ray pulsar signal models are considered, including the parallax effect, Shapiro delay, time dilation, and higher-order pulsar frequency models. The feasibility of solving the lost-in-space problem using X-ray pulsar navigation is revisited with the improved models and prior knowledge requirements are discussed. Monte Carlo simulation techniques are used to establish upper bounds on uncertainty and determine the accuracy of the algorithm. Results indicate that it is necessary to account for the parallax effect, time dilation, and higher-order pulsar frequency models in order to successfully determine the position of the spacecraft in a lost-in-space scenario. In a heliocentric case study, the algorithm uniquely identified a candidate spacecraft position within a spheroid search domain up to 10 × 10 × 0.01 AU 3 in size by simultaneously observing eight to nine pulsars. The maximum search domain size can be increased by observing additional pulsars, which may allow the lost-in-space problem to be solved anywhere within the Solar System. The median position error of the algorithm is on the order of 15 km. Results further indicate that choosing lower-frequency pulsars increases the maximum search domain size at the expense of increased position error. [ABSTRACT FROM AUTHOR]