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The Robertson-Walker (RW) metric, derived from the cosmological principle and Weyl's postulate, characterizes the ACDM cosmological model. Traditionally, in this framework, the assumption of a constant speed of light leads to specific cosmological time dilation (TD). However, because the Robertson-Walker metric lacks a way to define time dilation, the speed of light, like wavelength and temperature, may vary with cosmic time. The minimally extended varying speed of light (meVSL) model fits standard cosmological observations while considering the evolution of physical constants. One model-independent test for the meVSL model is cosmological time dilation. However, current data cannot distinguish between the meVSL model and the standard model. [ABSTRACT FROM AUTHOR]

The spin-torsion theory is a gauge theory approach to gravity that expands upon Einstein's general relativity (GR) by incorporating the spin of microparticles. In this study, we further develop the spin-torsion theory to examine spherically symmetric and static gravitational systems that involve free-falling macroscopic particles. We posit that the quantum spin of macroscopic matter becomes noteworthy at cosmic scales. We further assume that the Dirac spinor and Dirac equation adequately capture all essential physical characteristics of the particles and their associated processes. A crucial aspect of our approach involves substituting the constant mass in the Dirac equation with a scale function, allowing us to establish a connection between quantum effects and the scale of gravitational systems. This mechanism ensures that the quantum effect of macroscopic matter is scale-dependent and diminishes locally, a phenomenon not observed in microparticles. For any given matter density distribution, our theory predicts an additional quantum term, the quantum potential energy (QPE), within the mass expression. The QPE induces time dilation and distance contraction, and thus mimics a gravitational well. When applied to cosmology, our theory yields a static cosmological model. The QPE serves as a counterpart to the cosmological constant introduced by Einstein to balance gravity in his static cosmological model. The QPE also offers a plausible explanation for the origin of Hubble redshift (traditionally attributed to the universe's expansion). The predicted luminosity distance–redshift relation aligns remarkably well with SNe Ia data from the cosmological sample of SNe Ia. In the context of galaxies, the QPE functions as the equivalent of dark matter. The predicted circular velocities align well with rotation curve data from the SPARC (Spitzer Photometry and Accurate Rotation Curves database) sample. Importantly, our conclusions in this paper are reached through a conventional approach, with the sole assumption of the quantum effects of macroscopic matter at large scales, without the need for additional modifications or assumptions. [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 common opinion that the Lorentz transformation distorts the Minkowski spacetime arises from a mathematically incorrect neglect of its non-diagonal terms. When the non-diagonal Lorentz transformation is properly treated, the time dilation and the space distortion disappear. Consequently, the Lorentz metric produced by the Lorentz transformation is identical to the Minkowski metric. The spacetime distortion in moving inertial frames is properly described by the so-called Doppler metric produced by the Doppler transformation. This transformation assumes the existence of a preferred frame and depicts the Doppler shift of light for a moving light source and/or observer. The Doppler metric is Lorentz invariant and leaves the Maxwell's equations unchanged from their form in the Minkowski spacetime. Moreover, the Doppler metric is experimentally confirmed because it yields the null result in the Michelson–Morley experiment and other interferometric experiments. The suitability of the Doppler metric for describing light properties in Special and General Relativity is supported by recent cosmological observations of the cosmic microwave background. [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]

A question in physics is whether Special Relativity (SR) is the only theory that explains relativistic behavior. SR measures time dilation by a relative velocity between two frames. Laboratory experiments with a single moving body fit this concept. However, GPS satellites and their ground clocks measure time dilation by a velocity relative to a common non-rotating Earth inertial frame. To better understand the conceptual difference, an experimental survey was undertaken. The survey analysis showed that laboratory experiments also fit into the non-rotating Earth frame concept. The laboratory experiments only need to add the Earth rotational velocity to both the laboratory frame and the moving frame. The analysis also revealed that the relative velocity calculation was astonishingly close to the common Earth frame calculation. The common Earth frame then becomes the explanation for all experimental types. And it signifies that a gravity field – moving body interaction causes relativistic effects. The experimental record also contained enough data to draft an empirical kinetic theory different than SR. The “no preferred reference frame” of SR is replaced by “there is a preferred reference frame.” And the preferred frame is the nearby Earth gravity field.

Introduction: Anastomotic stricture is a common complication following esophageal atresia (EA) repair, substantially affecting the patient's quality of life (QoL). Multiple dilations are often required to maintain the appropriate diameter of the esophagus, leading to ongoing challenges. The aim of this study is to assess the efficacy of oral viscous budesonide (OVB) in prolonging the time between symptom recurrence and subsequent dilation. Methods: We carried out a retrospective single-center study for pediatric patients (0-18 years) who had undergone recurrent esophageal dilations (=3) following EA repair and initiated treatment with OVB (1 mg/day <10 years, otherwise 2 mg/day). Efficacy of treatment was determined by assessing a dysphagia symptom score (DSS) =1 for at least 3 months. Recurrence time to dysphagia and dilation were analyzed according to Kaplan-Meier method. Results: Of 29 patients screened, 19 were enrolled: 19/19 were responsive to OVB and 13/19 (68%) didn't required further dilations. The median time between dilations was significantly prolonged compared to the pre-treatment period [30 months vs 2months; p<0.01] as well as the time to dysphagia relapse [18months vs 1 month; p<0.01]. Conclusion: Topical budesonide has proven to be an effective treatment for recurrent esophageal stricture in repaired EA. Further investigation is required to assess the long-term sustained response of symptoms to topical steroids. [ABSTRACT FROM AUTHOR]

Recent research has indicated that attractive faces often cause a dilation of our time perception thus affecting physical and mental health, and speculates that this could be relevant to the fact that attractive faces capture people's attention. Nevertheless, there was no direct experimental data to support this speculation. The present work was designed to illustrate how attention affects time perception of facial attractiveness. It utilized two experiments to investigate this phenomenon. In Experiment 1, perception of timing and attention bias were assessed using a temporal reproduction task and a dot‐probe task. Increased attention bias was found to mediate the time dilation effect of facial attractiveness. Experiment 2 adopted dual‐task paradigm, combining a temporal reproduction task and attractiveness rating task, to manipulate attention allocation. The findings suggested that allocating more attention to the task requiring timing enhanced the time dilation effect caused by the faces. Results of Experiments 1 and 2 converge to show that attention plays an essential role in the effects of facial attractiveness on time perception. [ABSTRACT FROM AUTHOR]

This paper examines the possibility of controlling the outcome of measured (flat space-time) relativistic effects, such as time dilation or length contractions, using pure rotations and their nontrivial interactions with Lorentz boosts in the isometry group SO + (3 , 1) . In particular, boost contributions may annihilate leaving only a geometric phase (Wigner rotation), which we see in the complex solutions of the generalized Euler decomposition problem in R 3 . We consider numerical examples involving specific matrix factorizations, along with possible applications in special relativity, electrodynamics and quantum scattering. For clearer interpretation and simplified calculations we use a convenient projective biquaternion parametrization which emphasizes the geometric phases and for a large class of problems allows for closed-form solutions in terms of only rational functions. [ABSTRACT FROM AUTHOR]

The escape speed from one point-mass M1 is u1 = (--2U1)'=2 with U1 (= --M1G/s1) the (Newtonian) gravitational potential energy and s1 the distance between M1 and a chosen point. Observing that the escape speed, from two or more masses, increases, the total escape speed (i.e., from all the masses in universe) becomes u = (--2U)'=2, with U the total potential (energy), which is related, as shown, to the universe mass MU: According to many authors, Mu « 1053kg, and, on these bases, we found, on Earth, u ! c, so we assumed c = u. This equality implies the massiveness of the light, and because of its two related parameters, k and v, we inferred that the light has to be composed of longitudinal massive particles, photons (each one having length k), moving, along rays (succession of photons along the same direction), toward infinity with speed c (function of U), while their frequency v turns out to be their number, of the same ray, flowing in time unit. These particles, due to their speed and mass, have a momentum, and therefore, if photons and a circling electron should have, at their impact, opposite direction, the electron could fall into its nucleus; hence, the electron should have a different structure, where its charge is not uniformly distributed, whereas it can be considered as a point particle, fixed on the electron surface, facing the atom nucleus during the electron orbits, while the electron charge turns out to be the photons-electron impact point, where photons are absorbed and released. Due to this electron structure, the incident photons always force the impacting circling electron to move, with a radial velocity w (function of the incident photons frequency) toward wider orbits. On these bases, during these impacts, the electron becomes the source of re-emitted photons; hence, because of the Doppler effect involving both the incident photons and the recoiled electron, the frequency of the re-emitted photons decreases, while their length (due to the electron radial velocity w lasting as long as the interaction time T) increases by the value wT, inducing the invariance of the speed of light, despite any relative motion observer-source; we also found this invariance (which regards the interaction light-matter only) through the conservation of energy of the incident photons. Regarding the claimed time dilation, which occurs between two atomic clocks (ACs) at different potential U (e.g., at different altitude on Earth), it is shown that any variation DU implies a variation Dc, and, contemporarily, since the ACs are sources of photons at a given frequency on Earth, DU gives a variation of the ACs frequency Dv, hence of their ticking time T = 1/v, and therefore a variation of their counted time. Finally, the equality c = u implies a cosmological reason regarding an endless balance between collapse and dispersion of the universe masses. [ABSTRACT FROM AUTHOR]

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: Postoperative anal dilations (PAD) are the standard of care for patients after a posterior sagittal anorectoplasty (PSARP) for anorectal malformation (ARM) or a transanal pull-through (TP) procedure for Hirschsprung disease (HD). This study assessed the psychosocial impact of PAD among caregivers of children with ARM or HD, which may inform postoperative care strategies. Methods: Caregivers of patients with ARM and HD who underwent PSARP or TP within five years participated in the online survey. Questions included demographics, patient and caregiver experiences with PAD, and baseline psychosocial functioning. Quantitative results were reported descriptively, while qualitative responses were summarized as major themes. Results: The survey indicated a response rate of 26% caregivers, with most being female (91%) and biological mothers (85%). Patients were mostly male (65%), born with ARM (74%), and were five months old on average when PAD began. Caregivers reported that during PAD, children experienced distress (56%), pain (44%), and fear (41%), while a third noted no negative reactions. Over time, their child's ability to cope with PAD got easier (38%) or stayed the same (41%). Caregivers reported worry/anxiety (88%), guilt (71%), stress (62%), and frustration (35%), noting that additional coping strategies to manage the emotional and logistical challenges of daily PAD would be helpful. Conclusion: Although PAD is necessary, it can be highly stressful for the patients and their caregivers. Key findings emphasized the need for additional coping strategies and highlighted the importance of integrating psychosocial support into the postoperative care regimen. [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]

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 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]

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 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]

We report on the progress toward a dual-species cadmium and strontium atom interferometer for fundamental physics tests. We have developed and characterized a complete baseline laser system for cadmium, which provides the high power and narrow linewidth necessary for laser cooling and trapping and for performing atom interferometry, with upgraded systems for strontium also implemented. An overview of a design for cooling cadmium is presented, and we outline the basic design of a Cd–Sr atomic fountain, discussing atom launching techniques and the possible role of blackbody radiation. The excellent properties of cadmium and strontium, both individually and as a test pair, are discussed along with the enabled fundamental physics program of tests of the weak equivalence principle and the measurement of relativistic time dilation effects in quantum superpositions of clocks. [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]

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]

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]

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Reciprocal length contraction and time dilation, as enshrined in the Lorentz transformation, are the bulwark of the special relativity theory. Reciprocal time dilation is typically discussed (in the context of its apparent contradiction) and usually explained away as the result of differing synchronization in inertial reference frames and the relativity of simultaneity. Further, it is generally suggested that time is an abstract concept, and its perceptions may differ with context. However, we suggest that regarding length measurements no such abstraction can be envisaged. In this manuscript, we examine the reciprocal length contraction in detail to assess whether it leads to any contradiction. [ABSTRACT FROM AUTHOR]

The Hafele-Keating experiment showed the occurrence of time dilation in clocks placed on two airplanes, one moving eastward and one moving westward relative to the Earth's rotation. However, the application of the special theory of relativity failed to account for the significant differences in the data. This problem is solved by a novel approach that focuses on the absolute velocities of the clocks with reference to the Earth's rotation and uses space as a fixed reference point. The basic idea here is that time dilatation is an experimental fact and, therefore, independent from the theory behind it, so it is independent from relativism. Time dilatation also can occur under absolute conditions. Up until now, it is not clear if the concept of relativism is correct or not. The existence of time dilatation cannot be proofs for relativism as time dilatation also can occur under absolute conditions. Here, it is established that the eastbound plane had a higher absolute velocity than its westbound counterpart, resulting in time dilation figures of 50 and 140 ns, respectively. [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]

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]

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: Gastric conduit is most widely used method for esophageal reconstruction. Despite its popularity, certain complications, such as anastomotic leakage and strictures, remain to be resolved. In the present study, we reviewed the outcomes of narrow gastric conduit compared to wide gastric conduit reconstruction. Methods: We retrospectively reviewed 493 patients with esophageal cancer who received esophagectomy with reconstruction in Taichung Veteran General Hospital, Taiwan between January 2010 and December 2019. We performed gastric conduit reconstruction with two different methods, narrow gastric conduit made of multistaples (more than four staples) and wide gastric conduit made of two or three staples. Among the 493 patients, 170 patients underwent wide gastric conduit formation and 323 patients underwent narrow gastric conduit. After propensity score matching, 140 patients from each group were matched by 1:1. Results: The average anastomotic leakage rate is 80 of 493 (16.23%). The leakage rate, length of hospital stay, intensive care unit (ICU) admission, and ICU stay were significantly lower in the narrow gastric conduit group than in the wide gastric conduit group. The need for postoperation dilatation was significantly higher in wide gastric conduit group (19.41% vs 11.76%, p = 0.0217), and the time to first dilatation was similar in both groups (p = 0.9808). Similar results were observed even after propensity score matching. In univariate analysis, the narrow gastric conduit, circular stapler, video-assisted thoracic surgery, and laparoscopic surgery were associated with a reduced risk of anastomotic leakage. However, these factors are not statistically significant in a multivariate logistic regression analysis. Conclusion: The narrow gastric conduit is not inferior to the wide gastric conduit and can be considered an alternative option for gastric conduit preparation. [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]

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 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]

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]

This paper introduces three new criteria that a theory of personal identity ought to satisfy: (1) material holism, (2) narrative unity, and (3) narrative integrity. Material holism guards against the undesirable consequence of positing the person as part and existentially distinct from the organismal whole, of which it is dependent and interconnected. Narrative unity ensures that continuity between the beginning, middle, and end of a human life is sufficiently accounted for. Narrative integrity secures fidelity and congruence between each part and the whole, the whole to each part. Jeff McMahan's Embodied Mind Account (EM) fails to satisfy each of these. On McMahan's account, human persons and human organisms are distinct entities, human persons come into existence after its human organism, and human persons may go out of existence before their human organism. Moreover, fetuses, infants, the congenitally severely cognitively impaired, those with severe dementia, and the comatose are non-persons. A theory of personal identity that incorporates holism and narrative can provide a better explanation of human existence, life and death, and the identity paradox of dicephalic twins. If accepted, EM must either be rejected or ameliorated, and the new criteria ought to be incorporated in contemporary research of personal identity. [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]