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This paper develops the approach to special relativity put forward by John S. Bell. The classical dynamics of an electron orbiting a nucleus in uniform motion is solved analytically and compared to numerical simulations for an accelerated nucleus. The relativistic phenomena of length contraction and time dilation are shown to result from the electric and magnetic forces on the electron when its motion is analyzed in a single frame of reference. The relevance of these results for understanding the theory of special relativity is discussed. In this paper, the author explores a suggestion by John Bell for teaching special relativity: to introduce length contraction and time dilation as dynamical phenomena arising from the laws of motion, without reference to the Lorentz transformations. The paper provides historical and philosophical insight into the development of special relativity alongside an analysis of electron orbits in a classical model of an atom. Using only the Lorentz force law, the author illustrates the deformation of orbits of moving and accelerating atoms with approximate, exact, and numerical calculations that reveal time dilation and length contraction. Instructors may find these derivations useful in teaching courses on modern physics, relativity, classical mechanics, electrodynamics, or numerical methods. [ABSTRACT FROM AUTHOR]

Background: Percutaneous nephrolithotomy (PCNL) is the first line treatment for treating kidney stones larger than 2 cm size with the advantages of lower morbidity and faster post-operative recovery. Creation of a nephrostomy access is one of the major steps of PCNL. It can be done either by single-step dilatation or by multi-step serial dilatation technique. Objectives: To compare the outcome and evaluate the efficacy of percutaneous nephrolithotomy done by single-step versus serial dilatation technique with specific reference to access time, fluoroscopy time, rate of blood transfusion, length of hospital stay (post-op) and complication rate. Methods: It was a prospective study with a sample size of 100 where 50 patients underwent one-step dilatation and other 50 patients underwent serial-dilatation technique. These patients were analysed on the basis of their demographic profile, renal access time, total fluoroscopy time for access, post-operative haematuria, duration of post-operative hospital stay and complications after operative procedure. Data was analysed and reported using statistical tools. Results: Demographic profile of the patients and stone characteristics were equivalent between two groups. Mean access tract dilatation time, mean total fluoroscopy time were significantly less in one of the groups. Requirement of blood transfusion, and post-operative complications rate were not significant between two groups. Conclusion: Both methods are safe and effective for tract dilatation. However, PCNL can be successfully performed by one-step dilatation with the added advantages of lesser time of renal access, lesser radiation exposure. Blood loss and hospital stay after operative procedure were not statistically significant between two groups. [ABSTRACT FROM AUTHOR]

The theory of special relativity is one of the most significant achievements in modern physics, with several important predictions such as time dilation, size contraction for a moving object, and mass-energy equivalence. Recent studies have demonstrated size contraction for an antiferromagnetic (AFM) domain wall (DW). Here, we show the excitation of terahertz (THz) magnons from a moving AFM DW under the magnetic anisotropy energy gradient. The energy of magnons comes from the loss of the effective DW mass due to the reduction in anisotropy energy. Also, the excitation of THz magnons is accompanied by a DW width broadening, overcoming the Lorentz contraction effect. Our results pave the way to study relativistic physics in AFM textures and to efficiently generate THz magnons by DC electric means. [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]

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]

Time perception has been known to depend on the temporal frequency of the stimulus. Previously, the effect of temporal frequency modulation was assumed to be monotonically lengthening or shortening. However, this study shows that temporal frequency affects time perception in a non-monotonic and modality-dependent manner. Four experiments investigated the time distortion effects induced by modulation of temporal frequency across auditory and visual modalities. Critically, the temporal frequency was parametrically manipulated across four levels (steady stimulus, 10-, 20-, and 30/40-Hz intermittent auditory/visual stimulus). Experiment 1, 2, and 3 consistently showed that a 10-Hz auditory stimulus was perceived as shorter than a steady auditory stimulus. Meanwhile, as the temporal frequency increased, the perceived duration of the intermittent auditory stimulus was lengthened. A 40-Hz auditory stimulus was perceived as longer than a 10- Hz auditory stimulus, but did not differ significantly from a steady one. Experiment 4 showed that, for the visual modality, a 10-Hz visual stimulus was perceived as longer than a steady stimulus, and the perceived duration was lengthened as temporal frequency increased. This study demonstrated that within the scope of the temporal frequencies examined in this study, there were differential distortion effects observed across sensory modalities. [ABSTRACT FROM AUTHOR]

The objective of this work is to derive the structure of Minkowski spacetime using a Hermitian spin basis. This Hermitian spin basis is analogous to the Pauli spin basis. The derived Minkowski metric is then employed to obtain the corresponding Lorentz factors, potential Lie algebra, effects on gamma matrices and complex representations of relativistic time dilation and length contraction. The main results, a discussion of the potential applications and future research directions are provided. [ABSTRACT FROM AUTHOR]

Open in new tab Download slide OBJECTIVES After staged reconstruction for hypoplastic left heart syndrome, the neoaortic root tends to dilate, and the incidence of significant neoaortic valve insufficiency increases with time. This study aimed to evaluate the mid-term outcomes of the neoaortic root geometries and valve function after chimney reconstruction in the Norwood procedure. METHODS Between 2013 and 2021, 20 consecutive patients who underwent chimney reconstruction during the Norwood procedure for hypoplastic left heart syndrome and its variants in our institution were enrolled. The actual diameters of the following points were measured, and Z-scores were calculated based on the normal aortic root geometries using the long axis view of echocardiography at the pre-Norwood stage and the lateral view of angiography at pre-Glenn, pre-Fontan, post-Fontan and follow-up (age 5–6 years) stages: neoaortic valve annulus; sinus of Valsalva; sinotubular junction; and ascending aorta just proximal to the anastomosis to the aortic arch. The degree of neoaortic valve regurgitation was evaluated by echocardiography at each stage. RESULTS The median follow-up period was 3.9 years. Neoaortic roots after chimney reconstruction were spared from progressive dilation over time. With growth, the conical configuration of the neoaortic roots was preserved without geometrical distortion. The Z-scores of the annulus, sinus of Valsalva, sinotubular junction and ascending aorta ranged roughly from 4 to 6, 4 to 6, 2 to 4 and 0 to 2, respectively. All neoaortic valves at each stage had mild or no regurgitation. CONCLUSIONS Chimney reconstruction prevented neoaortic root dilation and avoided significant neoaortic valve regurgitation in the mid-term. These neoaortic dimensions with smooth flow profiles in the neoaorta after chimney reconstruction may have contributed to the current results. Further studies are needed to clarify the long-term outcomes. [ABSTRACT FROM AUTHOR]

The explanation of Einstein’s special theory of relativity in his original 1905 paper is examined. His analysis is confusing, as terms x, y, z, t, etc., have different meanings at various points, and he presents equations based on different and inconsistent assumptions. Adding subscripts clarifies these issues but exposes errors in his reasoning. To calculate his transformation equations, he selects a combination of equations which gives results matching the Lorentz transformation but he ignores other possible valid solutions. Also his calculations contain serious errors. Therefore, he fails to prove that his theory leads to the Lorentz equations as a unique solution. Einstein’s analysis includes “moving” clocks which show “stationary” time t, so the idea that a moving clock should run slower than a stationary clock is incompatible with his theory. Also, his calculation of time dilation contains serious errors. As a result, he fails to provide a theoretical justification for his famous “clocks paradox.” [ABSTRACT FROM AUTHOR]

MIS-C (Multisystem inflammatory syndrome in children) is a hyperinflammatory syndrome caused by the Sars-CoV-2 virus, still an ongoing issue worldwide. MIS-C is associated with an impairment of various organ systems, including the cardiovascular system, and up to 100% of all MIS-C patients have a broad spectrum and severity of symptoms. Identifying MIS-C early and starting therapy is crucial to minimise possible complications and clinical worsening. A prospective cohort study in a single centre was conducted at the Children's Clinical University Hospital in Latvia from January to December 2021. Patients between the ages of one and seventeen years who met the MIS-C criteria were included in the study. We evaluated the patient's demographic data, blood pressure, echocardiographic data, ESG data, and cardiac biomarkers such as proBNP and troponin I. Thirty-one patients were included who met the MIS-C criteria. The median age was 8.0 years, and 52% were boys. Of all patients, 77% initially presented with hypotension, and 42% required inotropic support. Treatment in the paediatric intensive care unit (PICU) was required in 58% of patients. Reduced left ventricular ejection fraction was observed in 35% of patients. Mildly decreased ventricular ejection fraction (< 55%) was observed in 19% of cases, and moderate dysfunction (ejection fraction < 45%) in 16% of patients. Twelve per cent of patients received milrinone to improve left heart function. Left heart function significantly improved in all patients during the hospitalisation. In 6% of all patients, coronary artery dilations were observed. All patients had dilation resolution at the time of discharge. The median length of hospitalisation was twelve days, and the median length of PICU stay was three days. Multisystem inflammatory syndrome in children is a significant and potentially life-threatening illness with cardiovascular involvement in 100% of cases. Patients who present primarily with higher ProBNP levels are more likely to have decreased left ventricle ejection fraction, which should be kept in mind when evaluating patients with MIS-C. Overall, patients with MIS-C have a good prognosis, and most cardiovascular changes have been resolved by discharge, but further follow-up and studies are needed to judge the long-term outcome. [ABSTRACT FROM AUTHOR]

Background: VDD (atrial sensing, ventricular sensing/pacing) leads are relatively rarely implanted; therefore, experience in their extraction is very limited. We aimed to investigate whether VDD lead removal may be a risk factor for the increased complexity of transvenous lead extraction (TLE) or major complications. Methods: We retrospectively analyzed 3808 TLE procedures (including 103 patients with VDD leads). Results: If TLE included VDD lead removal, procedure duration (lead dilation time) was prolonged, complicated extractions were slightly more common, and more advanced tools were required. This is partly due to longer implant duration (in patients with VDD systems—135.2 months; systems without VDD leads—109.3 months; p < 0.001), more frequent presence of abandoned leads (all systems containing VDD leads—22.33% and all systems without VDD leads—10.77%), and partly to the younger age of patients with VDD leads (51.74 vs. 57.72 years; p < 0.001, in the remaining patients) at the time of system implantation. VDD lead extraction does not increase the risk of major complications (1.94 vs. 2.34%; p = 0.905). Conclusions: The extraction of VDD leads may be considered a risk factor for increased procedure complexity, but not for major complications. However, this is not a direct result of VDD lead extraction but specific characteristics of the patients with VDD leads. Operator skill and team experience combined with special custom maneuvers can enable favorable results to be achieved despite the specific design of VDD leads, even with older VDD lead models. [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]

This article is devoted to the criticism of the wave-particle dualism and the provisions of the special theory of relativity (SRT). The fallacy of accepting the extended principle of relativity and identifying particles and waves is shown. The substantiation is given that the own fields of physical objects, which are material substances and spatially connect physical objects with each other, are the medium of propagation of light waves. The causal and visual picture of the propagation of light waves is considered, and the features of the mechanism of their propagation in comparison with other types of waves are described. On the basis of an alternative method for obtaining the relativistic law of velocities addition, the inconsistency of the principle of invariance of the interval adopted in the framework of SRT is shown. The inconsistency of the SRT positions and conclusions regarding the so-called relativistic effects-time dilation, mass increase, length decrease, as well as the energy of relativistic particles is shown. The presence of the clock paradox is shown by a simple example. The conclusion is made about the incorrectness of using mathematical transformations of Lorentz and the four-dimensional continuum in the physical representation. [ABSTRACT FROM AUTHOR]

Subjective time dilation is an effect discovered using the oddball paradigm, where expanding visual stimuli, but not shrinking ones, induce a prolongation of subjective temporal perception compared to static stimuli. This disparity is often seen as another demonstration of humans' evolved reaction to approaching threats, since visual expansion resembles approaching potential threats and warrants extra attention. In this study, we show that by manipulating the relative sizes of stimuli, both expanding and shrinking stimuli can induce prolongation of subjective time in an oddball paradigm. We propose an alternative explanation based on information theory, linking subjective temporal perception to entropy, an objective property of stimulus that is information uncertainty. Temporal function as a logistic function thus serves as the framework inside which content functions like information processing are able to operate coherently. [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]

Background: Cervical dilatation is an essential aspect of active labour, which is necessary for the progress of delivery. Delayed or inadequate cervical dilatation can lead to prolonged labour, fetal distress, and the need for instrumental delivery. Pharmacological agents, such as Drotaverine Hydrochloride and Valethamate Bromide, are commonly used to promote cervical dilatation and facilitate delivery. Aim: To Observe the effectiveness of Drotaverine Hydrochloride and Valethamate Bromide in Promoting Cervical Dilatation during Active Labour. Methodology: This was a randomized, observational study conducted at a tertiary care hospital. A total of 100 women in active labour, with a cervical dilatation of less than 4 cm, were included in the study. They were randomly divided into two groups, with 50 women in each group. The first group received Drotaverine Hydrochloride, while the second group received Valethamate Bromide. The drugs were administered intravenously as per the standard protocol. The rate of cervical dilatation was monitored in both groups for a period of 6 hours. Results: The mean rate of cervical dilatation in the Drotaverine Hydrochloride group was 1.7 cm/hour, while in the Valethamate Bromide group it was 1.2 cm/hour. The difference was statistically significant (p<0.05). The mean time for cervical dilatation of 4 cm was 2.5 hours in the Drotaverine Hydrochloride group, while in the Valethamate Bromide group it was 3.5 hours. The difference was statistically significant (p<0.05). The adverse effects observed in both groups were similar and mild. Conclusion: In this observational study, Drotaverine Hydrochloride was found to be more effective in promoting cervical dilatation during active labour as compared to Valethamate Bromide. However, further studies are needed to validate these findings and to explore the long-term effects of these drugs on maternal and fetal outcomes. [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]

Objective: This study aimed to develop and validate a prediction model of vaginal birth after cesarean delivery (VBAC) in China. Methods: A nomogram for effective prediction of VBAC of singleton, cephalic and one previous low‐transverse cesarean section deliveries was created by comparing the combinations of ultrasonographic and non‐ultrasonographic factors from five hospitals between 2018 and 2019. Results: A total of 1066 women were included. Of the women who underwent trial of labor after cesarean (TOLAC), 854 (80.1%) had a VBAC. Ultrasound factors included reached a higher area under the curve (AUC) combined with non‐ultrasonographic factors. Of the three ultrasonographic factors analyzed, the best predictive factor for successful TOLAC was fetal abdominal circumference. A nomogram was generated with eight validated factors, including maternal age, gestational week, height, previous vaginal delivery, Bishop score, dilatation of the cervix at the time of admission, body mass index at delivery, and fetal abdominal circumference by ultrasound. The trained and validated AUC were 0.719 (95% confident interval 0.674–0.764) and 0.774 (95% confident interval 0.712–0.837), respectively. Conclusion: Our VBAC nomogram based on obstetric factors and fetal abdominal circumference obtained by ultrasound could be used to counsel women who are considering TOLAC. Synopsis: Our VBAC nomogram based on obstetric factors and fetal abdominal circumference determined by ultrasound could be used to counsel women who are considering TOLAC. [ABSTRACT FROM AUTHOR]

The Friedmann–Lemaître–Robertson–Walker model establishes the correlation between redshifts and distances. It has a metric expansion of space. As a result, the wavelength of photons propagating through the expanding space is stretched, creating the cosmological redshift, z. It also relates the frequency of light detected by a local observer to that emitted from a distant source. In standard cosmology (i.e. a constant speed light model), this relation is given by a factor 1/(1 + z). However, this ratio is modified in the minimally extended varying speed of light model (meVSL, c  = c 0 a b /4) as 1/(1 + z)1 − b /4. This time dilation effect is detected as the observed rate of the time variation in the intensity of emitted radiation. The spectra of Type Ia supernovae (SNe Ia) provide a reliable way to measure the apparent aging rate of distant objects. We use data on 13 high-redshift (0.28 ≤ z ≤ 0.62) SNe Ia to obtain b  = 0.198 ± 0.415 at the 1-σ confidence interval. The current data is too sparse to give meaningful constrain on the meVSL and cannot distinguish the meVSL model from the standard model. [ABSTRACT FROM AUTHOR]

It is well known that simultaneity within an inertial frame is defined in relativity theory by a convention or definition. This definition leads to different simultaneities across inertial frames and the well-known principle of relativity of simultaneity. The lack of a universal present implies the existence of past, present, and future as a collection of events on a four-dimensional manifold or continuum wherein three dimensions are space like and one dimension is time like. However, such a continuum precludes the possibility of evolution of future from the present as all events exist "forever" so to speak on the continuum with the tenses past, present, and future merely being perceptions of different inertial frames. Such a far-reaching ontological concept, created by a mere convention, is yet to gain full acceptance. In this paper, we present arguments in favor of an absolute present, which means simultaneous events are simultaneous in all inertial frames, and subscribe to evolution of future from the present. [ABSTRACT FROM AUTHOR]

The special theory of relativity (STR) is based on two apparently contradictory postulates: The equality of all physical laws in all inertial reference systems and the invariance of the speed of light (c). This results in counterintuitive conclusions, including time dilation, object length contraction (i.e., Lorentz contraction), and mass increase at relativistic speeds as well as the unification of mass and energy. Although the STR has been empirically confirmed, the ultimate cause of special relativity as well as the reason for the invariance of c and its actual value (2.99 x 108 m/s) remain unknown. We have recently postulated that a hypothetical displacement of the three-dimensional (3D) space where we live throughout a fourth spatial dimension, which would be the basis for time, is a requirement for the gravitational effects contemplated by the general theory of relativity. This tetra-dimensional model of the universe explains that the actual value of c equals the speed at which our 3D space displaces along the fourth dimension. It also explains time dilation, Lorentz contraction, Lorentz transformation, and mass increase at relativistic speeds, as well as the unification of mass and energy, as epiphenomena derived from the projection of the fourth dimension to our 3D space. We conclude that our universe model can intuitively explain special relativity as well as the reason for the invariance of c and its actual value. [ABSTRACT FROM AUTHOR]

The principle of mental gravity contends that the mind uses physical gravity as a mental model or simulacrum to express the relation between the inner self and the outer world in terms of "UP"-ness and "DOWN"-ness. The simulation of increased gravity characterises a continuum of mental gravity which states includes depression as the paradigmatic example of being down, low, heavy, and slow. The physics of gravity can also be used to model spacetime curvature in depression, particularly gravitational time dilation as a property of MG analogous to subjective time dilation (i.e., the slowing of temporal flow in conscious experience). The principle has profound implications for the Temporo-spatial Theory of Consciousness (TTC) with regard to temporo-spatial alignment that establishes a "world-brain relation" that is centred on embodiment and the socialisation of conscious states. The principle of mental gravity provides the TTC with a way to incorporate the structure of the world into the structure of the brain, conscious experience, and thought. In concert with other theories of cognitive and neurobiological spacetime, the TTC can also work towards the "common currency" approach that also potentially connects the TTC to predictive processing frameworks such as free energy, neuronal gauge theories, and active inference accounts of depression. It gives the up/down dimension of space, as defined by the gravitational field, a unique status that is connected to both our embodied interaction with the physical world, and also the inverse, reflective, emotional but still embodied experience of ourselves. [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]

Perception of time is not always veridical; rather, it is subjected to distortions. One such compelling distortion is that the duration of regularly spaced intervals is often overestimated. One account suggests that excitatory phases of neural entrainment concomitant with such stimuli play a major role. However, assessing the correlation between the power of entrained oscillations and time dilation has yielded inconclusive results. In this study, we evaluated whether phase characteristics of neural oscillations impact time dilation. For this purpose, we entrained 10‐Hz oscillations and experimentally manipulated the presentation of flickers so that they were presented either in‐phase or out‐of‐phase relative to the established rhythm. Simultaneous electroencephalography (EEG) recordings confirmed that in‐phase and out‐of‐phase flickers had landed on different inhibitory phases of high‐amplitude alpha oscillations. Moreover, to control for confounding factors of expectancy and masking, we created two additional conditions. Results, supplemented by the Bayesian analysis, indicated that the phase of entrained visual alpha oscillation does not differentially affect flicker‐induced time dilation. Repeating the same experiment with regularly spaced auditory stimuli replicated the null findings. Moreover, we found a robust enhancement of precision for the reproduction of flickers relative to static stimuli that were partially supported by entrainment models. We discussed our results within the framework of neural oscillations and time‐perception models, suggesting that inhibitory cycles of visual alpha may have little relevance to the overestimation of regularly spaced intervals. Moreover, based on our findings, we proposed that temporal oscillators, assumed in entrainment models, may act independently of excitatory phases in the brain's lower level sensory areas. [ABSTRACT FROM AUTHOR]

Background: Platypnea-orthodeoxia syndrome (POS) is a relatively uncommon clinical syndrome characterized by dyspnea and deoxygenation accompanying postural changes, such as sitting or standing from a recumbent position. Case presentation: We describe the case of a 76-year-old woman who was hospitalized with dyspnea in the sitting position, which was relieved in the right lateral decubitus position. The patient was diagnosed with POS caused by a patent foramen ovale (PFO), dilation and elongation of the ascending aorta, and pectus excavatum. We performed PFO closure and replacement of the ascending aorta via median sternotomy. The patient's postoperative percutaneous oxygen saturation dramatically increased in the sitting position. Conclusions: Elongated and dilated ascending aorta and pectus excavatum with PFO may be risk factors for POS. In older patients, surgical intervention is an important treatment option for POS caused by cardiac and aortic comorbidities. [ABSTRACT FROM AUTHOR]

Time dilation (TD) is a principal concept in the special theory of relativity (STR). The Einstein TD formula is the relation between the proper time t 0 measured in a moving frame of reference with velocity v and the dilated time t measured by a stationary observer. In this paper, an integral approach is firstly presented to rededuce the Einstein TD formula. Then, the concept of TD is introduced and examined in view of the fractional calculus (FC) by means of the Caputo fractional derivative definition (CFD). In contrast to the explicit standard TD formula, it is found that the fractional TD (FTD) is governed by a transcendental equation in terms of the hyperbolic function and the fractional-order α. For small v compared with the speed of light c (i.e., v ≪ c ), our results tend to Newtonian mechanics, i.e., t → t 0 . For v comparable to c such as v = 0.9994 c , our numerical results are compared with the experimental ones for the TD of the muon particles μ + . Moreover, the influence of the arbitrary-order α on the FTD is analyzed. It is also declared that at a specific α , there is an agreement between the present theoretical results and the corresponding experimental ones for the muon particles μ + . [ABSTRACT FROM AUTHOR]

In my course "Time" I set out to disrupt the connection between cognitive tools used to represent time (clocks and calendars) and experiences of time. This article documents some of the topics and pedagogical methods I use: using unusual due dates for assignments, making the clock look strange, disrupting the idea of "now," showing how clocks cultivate gullibility, exploring the different hour systems of the past, criticizing clock-based logics used in primatological research, explaining the theory of special relativity, and exploring the political and economic consequences of sleep loss. [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: 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]

To treat men with bladder neck contracture (BNC) and stress urinary incontinence, neither long-term nor comparative data exist to support the superiority of simultaneous BNC intervention at the time of artificial urinary sphincter placement (synchronous) or staged BNC intervention followed by artificial urinary sphincter placement (asynchronous). This study aimed to compare the outcomes of patients treated with synchronous and asynchronous protocols. Using a prospectively maintained quality improvement database, we identified all men between the years of 2001-2021 with a history of BNC and artificial urinary sphincter placement. Baseline patient characteristics and outcome measures were collected. Categorical data were assessed with Pearson's Chi-square, and continuous data were assessed using independent sample t tests or the Wilcoxon Rank-Sum test. In total, 112 men met the inclusion criteria. Thirty-two patients were treated synchronously, and 80 were treated asynchronously. There were no significant differences between groups across 15 relevant variables. Overall follow-up duration was 7.1 (2.8, 13.1) years. Three (9.3%) in the synchronous group and 13 (16.2%) in the asynchronous group experienced an erosion. There were no significant differences in frequency of erosion, time to erosion, artificial sphincter revision, time to revision, or BNC recurrence. BNC recurrences after artificial sphincter placement were treated with serial dilation with no early device failure or erosion. Similar outcomes are achieved following synchronous and asynchronous treatment of BNC and stress urinary incontinence. Synchronous approaches should be considered safe and effective for men with stress urinary incontinence and BNC. [ABSTRACT FROM AUTHOR]

We present a novel test of the cosmological principle: the idea that, on sufficiently large scales, the Universe should appear homogeneous and isotropic to observers comoving with the Hubble flow. This is a fundamental assumption in modern cosmology, underpinning the use of the Friedmann–Lemaître–Robertson–Walker metric as part of the concordance ΛCDM paradigm. However, the observed dipole imprinted on the cosmic microwave background (CMB) is interpreted as our departure from the Hubble flow, and such a proper motion will induce a directionally-dependent time dilation over the sky. We illustrate the feasibility of detection of this 'time dilation dipole' and sketch the practical steps involved in its extraction from a catalogue of sources with intrinsic time-scales. In essence, whilst the scale of this dilation is small, being of the order of 0.1 per cent, it will in principle be detectable in large-scale surveys of variable cosmological sources, such as quasars and supernovae. The degree of alignment of the time dilation dipole with the kinematic dipole derived from the CMB will provide a new assessment of the cosmological principle and address the tension in dipole measures from other observations. [ABSTRACT FROM AUTHOR]

An appealing strategy for reconstructing the timing and tempo of paleoenvironmental change from sedimentary strata is to linearly interpolate between marker beds of known age. This method requires significant assumptions, but more advanced age modeling methods are usually not feasible. We used experiments to explore how changes in sedimentary processes invalidate these assumptions and affect estimates of time from the strata. When sedimentary processes changed to favor widespread deposition, we found that measuring time linearly systematically overestimated time duration from the resulting strata (time dilation) and misestimated the beginning and end of geologic intervals (phase shifting). When simple age models must be used for sedimentary strata, geologic evidence for transient changes in spatial sediment dispersal may help identify sections of dilated and shifted time, and better resolve time in sedimentary strata. Plain Language Summary: Sedimentary rocks can be used to measure the amount of time that passed between events in Earth history. Since it is rare to find layers of rock whose age can be measured, one needs a simplifying assumption: the thickness of sedimentary rocks is proportional to the amount of time that passed. In other words, the sediment accumulated relatively steadily, and gaps are short relative to the duration of interest. In this study, we show that this approach incorrectly dates events in the timeline, and erroneously inflates time durations. The bias is most significant when a change in environmental conditions causes sediment to spread more widely across the landscape than it did before. The bias is not as pronounced when sediment deposits are localized. Clues and context from sedimentary rocks may help reveal whether sediment was spreading widely or locally in the past. Using this evidence, geologists will be able to identify sections where simplifying assumptions will not hold, and can apply appropriate corrections. Key Points: If sediment dispersal changes through time and time is interpolated from long‐term rates, one will misestimate durations from strataMisestimation is not inevitable in the strata. Some changes in sediment dispersal result in distortion, while others do notGeologic clues that indicate the degree of sediment localization are key to diagnosing stratigraphic sections with substantial distortion [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]

Background: A treatment called hysteroscopy is used to examine and treat a number of gynecological issues. Objective: To compare misoprostol versus hyoscine butylbromide as a cervical priming agent in patients underlying hysteroscopy. Patients and methods: This randomized controlled clinical trial was carried out on 82 participants who were scheduled for operative hysteroscopy at Obstetrics and Gynecology Department, Zagazig University Hospitals. All participants in our study were divided randomly for cervical ripening prior to hysteroscopy into two groups; Group (A): Misoprostol was administrated (n=41), Group (B): Hyoscine butylbromide was administrated (n= 41). All patients were subjected to full history taking, routine clinical examination and laboratory investigations. The cervical priming agent was administrated 2 hours before the scheduled hysteroscopy. Results: There was no statistically significant difference between the two studied groups regarding age, height, weight, BMI, the mean parity, previous history of CS, history of abortion, the diagnosis, the procedure time, and anesthesia. Cervical dilatation width was significantly higher among group A while cervical dilatation time was significantly lower among group A than group B. The self-reported pain was significantly higher among group A than group B. Nearly 44% of the participants of group A needed postoperative analgesia administration, while only 12.2% of group B needed postoperative analgesia administration. Conclusion: Hyoscine butylbromide is as effective as misoprostol as a cervical priming agent in patients undergoing operative hysteroscopy with less need for postoperative pain medication and postoperative complications. [ABSTRACT FROM AUTHOR]

Relativistic time deals with concepts as spacetime and time dilation. I will try to explain this as clearly as possible. To explain the concept of spacetime is not at all impossible, although it is four-dimensional. But that means that we define it using four numbers. If we describe us through age, weight, height, and IQ, that would be a fourdimensional representation of us. [ABSTRACT FROM AUTHOR]

Whether they are theologians, lay people, or non-believers, most have at least anecdotally heard of the miracle of Jesus walking on water. Many important lessons and insights can be gleaned from this important passage, including testimony to the identity of Jesus that bolsters belief in Him and His deity and a non-trivial display of Jesus' power over His creation. However, was God trying to convey more than just His ability to elude physics, and displaying His authority over the dimension of time and its creation? The dimension of time is an elusive and much debated dimension that is difficult to understand, and in the context of God and heaven, it is in many respects beyond human comprehension. However, as expressed by Albert Einstein, "the distinction between the past, present and future is only a stubbornly persistent illusion." This illusion can only be unlocked by God, and thus it was created by God. In this article, the miracle of Jesus walking on water is explored in relation to the phenomenon of gravitational time dilation; it is considered as an instance that reveals God's relation to time, as well as the complexity and awesomeness of creation in general. We show that the equations for time dilation around a massive body may serve as a model to show the independence of God from His creation of spacetime. [ABSTRACT FROM AUTHOR]

General relativistic instability supernovae (GRSNe) at 10 ≲ z ≲ 15 are predicted to be observed as red faint point sources, and they can be detected only in the reddest filters in James Webb Space Telescope (JWST)/NIRCam (F444W and F356W). They should be observed as persistent point sources with little flux variations for a couple of decades because of time dilation. We search for static point sources detected only in the F444W filter or only in the F444W and F356W filters in the early JWST deep field data. No real point source of such kind is identified. Therefore, the GRSN rate at 10 ≲ z ≲ 15 is constrained to be less than ∼8 × 10−7 Mpc−3 yr−1 for the first time. [ABSTRACT FROM AUTHOR]

Time-resolved studies have so far relied on rapidly triggering a photo-induced dynamic in chemical or biological ions or molecules and subsequently probing them with a beam of fast moving photons or electrons that crosses the studied samples in a short period of time. Hence, the time resolution of the signal is mainly set by the pulse duration of the pump and probe pulses. In this paper, we propose a different approach to this problem that has the potential to consistently achieve orders of magnitude higher time resolutions than what is possible with laser technology or electron beam compression methods. Our proposed approach relies on accelerating the sample to a high speed to achieve relativistic time dilation. Probing the time-dilated sample would open up previously inaccessible time resolution domains. [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]

Considering that an Einstein clock can travel at a speed no greater than c, from the principle of relativity, a kinematic time dilation factor can be derived whose value cannot be greater than √2. In fact, however, the kinematic time dilation factor c can approach an infinite value. This discrepancy demonstrates that the derivation of the kinematic time dilation factor c in Einstein's special relativity (SR) cannot be physically justified by the principle of relativity, and that it is not physically possible that the speed of light is constant in any frame of reference. The mathematical method of Einstein's SR, which I refer to as the "mathematical method of relativity," allows the calculation of constant physical values from different quantities of any physical unit and is thus scientifically worthless. Accordingly, it is not surprising that it is possible to predict so-called general relativistic phenomena, e.g., the phenomena observed at the binary pulsar PSR B1913 + 16, just by applying Kepler's second law and simple quantum physical considerations [R. G. Ziefle, Phys. Essays 33, 99 (2020)]. A careful interpretation of interferometer experiments on Earth clearly shows that there is in fact no need for artificial time acceleration by length contraction. However, today's physicists seem to be lost in mathematics. The aim of this paper is to contribute to a physical theory of relativity that does not require mathematical tricks, such as time acceleration (length contraction), space-time curvature, and other mathematical tricks that follow from Einstein's mathematical methods and uphold the illusion that the belief in a constant speed of light c in any frame of reference is physically justified. [ABSTRACT FROM AUTHOR]

The importance of synchronization of spatially separated clocks in observing event coordinates cannot be overemphasized. We illustrate this with a real-world example. The results show the dependence of both length contraction and time dilation on the adopted synchronization convention. It is illustrated that a change in synchronization convention completely alters the appearance of the physical world. This is to be viewed in the context of the stated position in physics that synchronization of spatially separated clocks in any inertial frame depended on the adoption of a convention for its resolution. The preferred method of synchronization of spatially separated clocks is the standard convention recommended by the theory of relativity; however, it still remains a convention. [ABSTRACT FROM AUTHOR]

Researchers in standard gravity theory and cosmology seldom take into account Lorentz relativistic mass. The dismissal of Lorentz relativistic mass by the research community has happened without first properly investigating what predictions incorporating it in gravity models have led to. We show that the inclusion of Lorentz relativistic mass in some gravity theories has a dramatic impact on the predicted redshift from objects with high gravitational field such as stellar objects fitting the mathematical properties of black holes. Taking into account Lorentz relativistic mass provides diverse interpretations of quasars and many other objects. As relevant example, it may explain the lack of observed velocity time dilation in quasars. [ABSTRACT FROM AUTHOR]

Time is the fabric of experience – yet it is incredibly malleable in the mind of the observer: seeming to drag on, or fly right by at different moments. One of the most influential drivers of temporal distortions is attention, where heightened attention dilates subjective time. But an equally important feature of subjective experience involves not just the objects of attention, but also what information will naturally be remembered or forgotten, independent of attention (i.e., intrinsic image memorability). Here we test how memorability influences time perception. Observers viewed scenes in an oddball paradigm, where the last scene could be a forgettable "oddball" amidst memorable ones, or vice versa. Subjective time dilation occurred only for forgettable oddballs, but not memorable ones – demonstrating an oddball effect where the oddball did not differ in low-level visual features, image category, or even subjective memorability. But more importantly, these results emphasize how memory can interact with temporal experience: memorable beginnings may put people in an efficient encoding state, which may in turn influence which moments are dilated in time. [ABSTRACT FROM AUTHOR]

The Sagnac effect and related twin paradox with a rotating disc are analyzed. It may seem that the special theory of relativity gives an easy and exhaustive treatment here. However, such consideration is deceptive since the principles of special relativity are originally established only for the inertial frames of reference, whereas the Sagnac experiment and the twin paradox exist in a noninertial one. We introduce an additional group of motions related to the rotation with uniform angular speed and show that these transformations leave the Minkowski metric invariant. Thus, we can give a firm mathematical ground to a usual easy consideration of the Sagnac effect. It should be noted that the presented result is true for a special case of motions; general coordinate transformations into accelerating frames of reference do not preserve the metric. [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 special relativity, the time dilation formula has been obtained by particles propagation in a straight line trajectory relative to an observer in motion. Up to now, there are no available formulas for other possible trajectories of particles. However, this paper obtains formulas of time dilation for several trajectories of particle such as parabolic, elliptic, and circular and finds a relatively accurate trajectory. The obtained formulas are employed in order to analyze the time dilation of the muon particles decay. In this paper, it is found that the time dilation of the parabolic and the elliptical trajectories exceed the corresponding results utilizing the standard Lorentz-Einstein time dilation formula. Consequently, if we are able to control the trajectory of unstable particles by some external forces, then their life-times might be increased. Probably, the increase in lifetime via a curved trajectory occurs at lower relative velocity & acceleration energy if compared to the straight line trajectory. In addition, the circular trajectory leads to multiple values of time dilation at certain velocities of an observer in motion, which may give an interpretation of fluctuations of time dilation in quantum mechanics. The result arises from the present relatively accurate formula of time dilation that is very close to the experimental data of muon decay (CERN experiment) when it is compared to the result obtained by the Lorentz-Einstein formula. Finally, it may be concluded that the time dilation not only depends on relative velocity and acceleration energy of particles but also on curved trajectories. The present work may attract other researchers to study different trajectories. [ABSTRACT FROM AUTHOR]

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]

This essay weaves together elements of the concepts of spacetime, demons and the U.S. popular culture concept of demon time to postulate the end of the world and bring a conclusion to white supremacist and anti-African American worlds. Topics discussed are Black posthumanism as the foundation of Black transhumanism or technological materialization, time dilation as an element for understanding how African Americans experience time, and demon time as a way to bring African American realities.