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Recently, a static gravitational field, such as that of the Earth, was proposed as a new source of decoherence [1] . We study the conditions under which it becomes the dominant decoherence effect in typical interferometric experiments. The following competing sources are considered: spontaneous emission of light, absorption, scattering with the thermal photons and collisions with the residual gas. We quantify all these effects. As we will see, current experiments are off by several orders of magnitude. New ideas are needed in order to achieve the necessary requirements: having as large a system as possible, to increase gravitational decoherence, cool it and isolate well enough to reduce thermal and collisional decoherence, and resolve very small distances. [ABSTRACT FROM AUTHOR]

This experiment examined the effect of a train of regular repetitive clicks of different frequencies (8 Hz, 20 Hz) on time judgment in a bisection task in children aged 5 and 8 years old and adults with two duration ranges (200/800 and 400/1600 ms). Participants’ scores on neurospychological tests assessing memory, information processing speed and different components of attention control were also measured. The results showed that a train of clicks produced a time dilation in the children as well as in the adults, with the result that the perceived duration was judged to last longer with than without clicks. However, the time dilation reached a maximum level at a lower click frequency value (8 Hz) in the children than in the adults (20 Hz). In addition, beyond this click value (8 Hz), a reversal effect was observed in the youngest children, who responded “long” less often, while the time dilation was extended in the adults. In addition, while the differences in the time dilation between the click and the no-click condition were not correlated with the individual cognitive capacities, those that occurred when the click frequency increased from 8 to 20 Hz were significantly correlated with individual capacities in terms of attention and working memory. The hypothesis of a slower internal clock in the younger children is discussed as are the attentional interference processes involved in the click effect on time judgment. [ABSTRACT FROM AUTHOR]

Reflected laser light spots on distant targets were observed for 24 h periods by two separate laboratories. Although claims made in one study suggested this was not the case, in fact both data sets indicate no sufficiently significant shift of the centers of the reflected spots on the targets as the earth orbited and revolved during the measurements. This means that photons from the laser sources also travel lateral with the earth and targets so as not to shift the target arrival spot. This demonstrates the phenomenon termed synchronous aberration. The fact that photons do not follow the linear line along the ground between source and target but rather follow a diagonal, from the source at an original position to the target at a later shifted position, means that a stationary outside observer, but not an observer moving with the system, could be aware of the distance traveled to compute time for the event. Time dilation due to motion in special relativity theory is thus disproven, where a moving observer would merely use the ground distance between source and target to compute time incorrectly. Time for a light event is not dependent on motion of an observer that does not control the event, but may be incorrectly computed by an observer in motion. Physics texts must be corrected to avoid this long-held misconception in the future. [ABSTRACT FROM AUTHOR]

Background: Postoperative dysphagia after anti-reflux surgery typically resolves in a few weeks. However, even after the initial swelling has resolved at 6 weeks, dysphagia can persist in 30% of patients necessitating esophageal dilation. The purpose of this study was to investigate the effect of esophageal dilation on postoperative dysphagia, the recurrence of reflux symptoms, and the efficacy of pneumatic dilations on postoperative dysphagia. Methods: A prospectively collected database was reviewed for patients who underwent partial/complete fundoplication with/without paraesophageal hernia repair between 2006 and 2014. Patient age, sex, BMI, DeMeester score, procedure type, procedure duration, length of stay, postoperative dysphagia, time to first pneumatic dilation, number of dilations, and the need for reoperations were collected. Results: The study included 902 consecutive patients, 71.3% females, with a mean age of 57.8 ± 14.7 years. Postoperative dysphagia was noted in 26.3% of patients, of whom 89% had complete fundoplication (p < 0.01). Endoscopic dilation was performed in 93 patients (10.3%) with 59 (63.4%) demonstrating persistent dysphagia. Recurrent reflux symptoms occurred in 35 (37.6%) patients who underwent endoscopic dilation. Patients who underwent a dilation for symptoms of dysphagia were less likely to require a revisional surgery later than patients who had dysphagia but did not undergo a dilation before revisional surgery (17.2% vs 41.7%, respectively, p < 0.001) in the 4-year follow-up period. The duration of initial dilation from surgery was inversely related to the need for revisional surgery (p = 0.047), while more than one dilation was not associated with additive benefit. Conclusion: One attempt at endoscopic dilation of the esophagogastric fundoplication may provide relief in patients with postoperative dysphagia and can be used as a predictive factor for the need of revision. However, there is an increased risk for recurrent reflux symptoms and revisional surgery may ultimately be indicated for control of symptoms. [ABSTRACT FROM AUTHOR]

Jet component positions with respect to the core as a function of time and the fitted proper motions. The left and right panels show the projected motions along and perpendicular to the jet direction, respectively. High-resolution observations of high-redshift (z > 4) radio quasars offer a unique insight into jet kinematics at early cosmological epochs, as well as constraints on cosmological model parameters. Due to the general weakness of extremely distant objects and the apparently slow structural changes caused by cosmological time dilation, only a couple of high-redshift quasars (HRQs) have been studied with parsec-scale resolutions, and with limited number of observing epochs. Here we report on very long baseline interferometry (VLBI) observations of a high-redshift blazar J1430 + 4204 (z = 4.72) in the 8 GHz frequency band at five different epochs spanning 22 years. The source shows a compact core–jet structure with two jet components being identified within 3 milli-arcsecond (mas) scale. The long time span and multiple-epoch data allow for the kinematic studies of the jet components. That results in a jet proper motion of μ (J 1) = 0.017 ± 0.002 mas a - 1 and μ (J 2) = 0.156 ± 0.015 mas a - 1 , respectively. For the fastest-moving outer jet component J2, the corresponding apparent transverse speed is (19.5 ± 1.9) c. The inferred bulk jet Lorentz factor Γ = 14.6 ± 3.8 and viewing angle θ = 2.2 ° ± 1.6 ° indicate highly relativistic beaming. The Lorentz factor and apparent proper motion are the highest measured to date among the z > 4 jetted radio sources, while the jet kinematics is still consistent with the cosmological interpretation of quasar redshifts. [ABSTRACT FROM AUTHOR]

Red-bed argillaceous sandstone is a typical soft rock with swelling characteristics and is prone to cause problems in engineering geology such as dilation deformation when used in high-speed railway subgrades or uneven settlement when used in foundations. This potential impact emphasizes the importance of understanding the long-term dilation and contraction of red-bed soft rocks. To thoroughly study the dilation properties of red-bed soft rock, the evolution of red-bed argillaceous sandstone dilation over time was characterized through a series of tests. The red-bed argillaceous sandstone dilation has a conspicuous time effect, and the dilatability shows an increasing reverse sigmoidal curve with increasing time. The dilation deformation gradually increases with increasing dry–wet cycle number until the shrinkage deformation offsets the dilation deformation, finally reaching a balance between dilation and shrinkage. Here, the microscopic mechanism of red-bed argillaceous sandstone dilation was revealed by qualitative analysis of microscopic unit particles and quantitative analysis of microscopic pores. A logistic evolution model was established based on molecular microkinetics, with the inflection point (t 0) and slope (p) of the dilation curve. The mathematical significance and applicability of the logistic model were verified by model comparison, model application and parametric analysis. The dilation scale and velocity were determined to be restrained by the axial load, and the decrease in the gap between dilation-time curves indicated that the inhibitory effect of the axial load on the expansion potential was nonlinear; with the same axial load increment, this effect weakened with increasing load. Finally, a three-dimensional dilation constitutive model considering the microkinetic time model was proposed to amend the traditional one-dimensional dilation model, and the practicality of this three-dimensional model was evaluated against measured data. The results provide a theoretical reference for solving argillaceous sandstone swelling problems in water-rich red-bed rock and determining the long-term deformation mechanism of high-speed railway subgrades. • Logistic distribution curve describes the evolution of the dilation with time. • Face-face connections have the most favourable spatial arrangement for expansion. • Dilation scale and velocity were determined to be restrained by axial loading. • A three-dimensional dilation constitutive model considering time effect was proposed. [ABSTRACT FROM AUTHOR]

All the existing source seeking algorithms for unicycle models in GPS-denied settings guarantee at best an exponential rate of convergence over an infinite interval. Using the recently introduced time-varying feedback tools for prescribed-time stabilization, we achieve source seeking in prescribed time, i.e., the convergence to a small but bounded neighborhood of the source, without the measurements of the position and velocity of the unicycle, in as short a time as the user desires, starting from an arbitrary distance from the source. The practical convergence is established using a singularly perturbed version of the Lie bracket averaging method, combined with time dilation and time contraction operations. The algorithm is robust, provably, even to bounded nonvanishing perturbations and an arbitrarily strong gradient-dependent repulsive velocity drift emanating from the source. [ABSTRACT FROM AUTHOR]

Under gravity's rainbow, we investigate its effects on the gravitational time advancement, which is a natural consequence of measuring proper time span for a photon's round trip. This time advancement can be complementary to the time delay for testing the gravity's rainbow, because they are sensitive to different modified dispersion relations (MDRs). Its observability on ranging a spacecraft far from the Earth by two radio and a laser links is estimated at superior conjunction (SC) and inferior conjunction (IC). We find that (1) the IC is more favorable than the SC for measurement on the advancement caused by the rainbow; (2) a specific type of MDR has a significantly larger effect on the advancement than others in both SC and IC cases; and (3) a combination of available optical clocks and the realization of planetary laser ranging in the future will benefit distinguishing the gravity's rainbow from GR by measuring the gravitational time advancement. [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]

This work develops an autonomous trajectory planning algorithm for 6-DOF asteroid landing. The trajectory planning problem is formulated as a nonconvex time-optimal optimization problem with two-phase free final time, while the cost is regularized by augmenting a fuel consumption penalty. The nonconvex optimization problem is solved in successive solution method, and successive convexification is used to convert the original nonconvex problem into a sequence of convex subproblems, where each subproblem is obtained by linearizing the nonconvex dynamics and state constraints and using the velocity increment to give a convex expression of the fuel consumption penalty in cost function. Specifically, in the linearization, we divide the flight time interval into two parts and normalize each part using a time dilation coefficient to solve the problem that both the final times for the two flight phases are unknown, so that the original free final time problem turns to a fixed-time problem by minimizing the sum of the two time dilation coefficients and fuel consumption penalty. Besides, trust regions and virtual control are used to increase robustness of the algorithm. A convergence analysis is presented which indicates the successive solution will recover the local optimality of the original problem. Then the validity of the proposed algorithm and effects of different factors on flight time and fuel consumption are examined by simulations of landing on an irregular asteroid. [ABSTRACT FROM AUTHOR]

Abstract: Chemically strengthened glass produced via the ion exchange process has found many interesting applications due to its high strength and damage resistance. It is known that salt bath poisoning has a strong effect on mutual diffusivity during the ion exchange process. Salt bath poisoning occurs when cations previously in the glass contaminate the molten bath nominally consisting of a larger substituting cation. In this work, we introduce a simple two-level model describing the impact of salt bath poisoning on the mutual diffusion coefficient. The model is compared to experimentally measured values of mutual diffusivity over a wide range of salt bath poisoning and glass composition. The model is shown to agree well with the experimental data. We also quantify the dependence of the activation energy for mutual diffusivity on the initial concentration of the substituting cation in the base glass composition. Finally, we address the issue of network dilation during ion exchange, showing that the magnitude of the “network dilation anomaly” is lower for aluminosilicate glasses as compared to soda lime float glasses, enabling them to achieve closer to their ideal values of strength. [Copyright &y& Elsevier]

Objectives: To evaluate mifepristone impact on osmotic dilator placement and procedural outcomes when given 18 to 24 hours before dilator placement for dilation and evacuation (D&E) at 18 weeks 0 days to 23 weeks 6 days gestation.Study Design: We performed a randomized, double-blind, placebo-controlled trial from April 2019 through February 2021, enrolling participants undergoing osmotic dilator (Dilapan) placement for a planned, next-day D&E. Participants took mifepristone 200 mg or placebo orally 18 to 24 hours before dilator placement. We used a gestational age-based protocol for minimum number of dilators. Our primary outcome was the proportion of participants for whom 2 or more additional dilators could be placed compared to the minimum gestational age-based standard. We secondarily evaluated cervical dilation after dilator removal in the operating room, subjective procedure ease, and complication rates (cervical laceration, uterine perforation, blood transfusion, infection, hospitalization, or extramural delivery).Results: Of the planned 66 participants, we enrolled 44 (stopped due to coronavirus disease 2019-related obstacles), and 41 (19 mifepristone; 22 placebo) completed the study. We placed 2 or more additional dilators compared to standard in 7 (36.8%) and 3 (13.6%) participants after mifepristone and placebo, respectively (p = 0.14). We measured greater median initial cervical dilation in the mifepristone (3.2 cm[2.6-3.6]) compared to placebo (2.6 cm[2.2-3.0]) group, p = 0.03. Surgeon's perception of procedure being "easy" (8/19[42.1] vs 9/22[40.9], respectively, p = 1.00) and complication rate (3/19[15.8%] vs 3/22[13.6], respectively, p = 1.00) did not differ.Conclusion: Our underpowered study did not demonstrate a difference in cervical dilator placement, but mifepristone 18 to 24 hours prior to dilators increases cervical dilation without increasing complications.Implications: Mifepristone 18 to 24 hours prior to cervical dilator placement may be a useful adjunct to cervical dilators based on increased cervical dilation at time of procedure; however, logistical barriers, such as an additional visit, may preclude routine adoption without definite clinical benefit. [ABSTRACT FROM AUTHOR]

The concepts of a time ruler and space ruler are put forward, where the zoom of the space-time ruler provides for an intuitive explanation of the time dilation and length contraction effects associated with theory of relativity. Mass and energy can be regarded as measurements of matter by the time ruler, while momentum can be regarded as a measurement of matter by the space ruler. The space-time ruler can be divided into two kinds according to the causes of its deformation: a relative motion space-time ruler and a gravitational field space-time ruler. It is proved that there is equivalence between these two kinds of rulers under weak field conditions, with this amounting to another expression of the equivalence principle in general relativity. It is pointed out that the two kinds of space-time ruler can be superposed, with the formula for calculating the clock difference between satellites and ground stations being given by this superposition. A GPS satellite is used as an example to calculate clock difference in this way, and the calculation results are in agreement with the classical formula. [ABSTRACT FROM AUTHOR]

• The duration of self-name was overestimated relative to unfamiliar names. • The duration of self-referential negative trait words was perceived to be longer than those in friend-referential way. • The mechanism underlying time dilation of self-referential information involves attention. Previous studies have shown that stimuli with subjective salience could affect duration estimation. Although self-referential stimuli possess high biological and social importance, no prior study has examined whether and how self-referential information affects duration perception. Experiment 1 used the temporal bisection task to investigate participants' duration estimation of the presentation of their own name versus familiar and unfamiliar names. The results showed that participants overestimated the duration of their own name and became more sensitive to duration perception in such trials when compared with stranger's names. Given the specificity of personal name, Experiment 2 used two types of personality-trait words in self-referential and friend-referential manner as the targets of duration perception. The duration of self-referential negative trait words was perceived to be longer relative to friend-referential negative trait words. The mechanism underlying the subjective time dilation effect of self-referential information possibly involves the engagement of increased attentional resources, which could allow the individual to preserve a certain level of stability and positivity of self-knowledge. [ABSTRACT FROM AUTHOR]

Abstract: The dilation of a Euclidean graph is defined as the ratio of distance in the graph divided by distance in . In this paper we consider the problem of positioning the root of a star such that the dilation of the resulting star is minimal. We present a deterministic -time algorithm for evaluating the dilation of a given star; a randomized expected-time algorithm for finding an optimal center in ; and for the case , a randomized expected-time algorithm for finding an optimal center among the input points. [Copyright &y& Elsevier]

Abstract: We show that the phase transition from the decelerating universe to the accelerating universe, which is of relevance to the cosmological coincidence problem, is possible in the semiclassically quantized two-dimensional dilaton gravity by taking into account the noncommutative field variables during the finite time. Initially, the quantum-mechanically induced energy from the noncommutativity among the fields makes the early universe decelerate and subsequently the universe is accelerating because the dilaton driven cosmology becomes dominant later. [Copyright &y& Elsevier]

The working principle of pulse-dilation framing camera is introduced and the influence of dilating pulse on the character of dilation is theoretically analyzed. The exposure time and dilation factor are measured using the an array of fiber bundle(AFB), the jitter time of dilating pulse is calculated by the relation between dilation factor and dilating pulse. The experimental results show that the dilation factor is instability by the jitter of dilating pulse and the jitter time of dilating pulse is calculated by variation of the dilation factor. When the photocathode is biased −3 kV dc , the maximum and minimum dilation factors are approximately 7.02× and 5.35×, where the AFB are respectively synchronized with the rising time on 290 ps and 174 ps in the dilating pulse. According to the deference of the two rising times, the jitter time of dilating pulse is 116 ps. [ABSTRACT FROM AUTHOR]

Abstract: We propose a test of the gravitational time dilation in general relativity by long term clock comparison between two stations separated in height. The geopotential difference between the two National time keeping centers in China, Lintong and Beijing is around 4000 geopotential unit, which corresponds to the height difference of 400m. Two clocks and are fixed at stations A and B, respectively, which are synchronized at beginning by a portable clock C in a short time period with go-back synchronization approach. After one month, the clock C is again transported between A and B, comparing the records of the keeping time by clocks and , respectively. Calculations show that, after one month, the difference of the time durations between the clocks and is around 121ns, if general relativity is correct. [Copyright &y& Elsevier]

Offers a look at physicist-philosopher Herbert Dingle's twin paradox. A glance at Dingle's life; Examination of Dingle's writings not directly related to the controversy; Exposition of history and physical and philosophical issues involved in the twin paradox; Exposition of the controversy; Concluding remarks; Battle of purposes; Tyranny of mathematics; Critical spirit.

A pulse-dilation framing camera is developed and the principle of pulse-dilation is introduced. The obtainment method of different gradient is discussed and implemented. The influence of gradients on temporal performance is theoretical and experimental studied. The research results show that the different gradients are achieved by altering resistance with between output port of the pulse generator and input port of the PC, the corresponding exposure time and dilation factor of measurement are agree well with the theoretical analysis. This research is verify and analyze the influence of gradient of dilation pulse on temporal performance of pulse-dilation framing camera. [ABSTRACT FROM AUTHOR]

A pulse-dilation framing camera and its working principle are introduced. The exposure time with less than 10-ps is measured by an array of fiber bundle. The research results show that the shortest exposure time and maximum dilation factor of camera are approximately 5 ps and 16.4×, respectively. The exposure time with less than 10-ps can be achieved when the drift potential is less than 5 kV and the gradient of dilation pulse is greater than 6 V/ps, those are provide feasibility for the framing camera with exposure time less than 10-ps. [ABSTRACT FROM AUTHOR]

Objective: To describe effectiveness of funic potassium chloride (KCl) injection for fetal demise during intact dilation and evacuation (D&E).Study Design: We abstracted medical records of patients who underwent standard or intact D&E to identify those who had intact D&E from 20 weeks 0 days through 23 weeks 6 days from February 2016 to August 2017 at one academic center. We extracted data on time to asystole following KCl injection, as well as incidents including hemorrhage, infection, uterine perforation, and unplanned admissions for up to 6 months following each procedure.Results: Of 57 procedures, 32 (56%) were intact. Median time from KCl injection to fetal asystole was 48 seconds (interquartile range [IQR] 34-100). Median time to asystole at weeks 20 and 21 (46 seconds [IQR 34-60 seconds]) did not differ significantly from weeks 22 and 23 (85 seconds [IQR 34-200 seconds]), p = 0.15. Asystole occurred in less than four minutes in all cases but one. No adverse events occurred with either the funic KCl injections or the intact D&E procedures.Conclusion: Funic KCl injection for intact D&E usually causes fetal asystole in less than 4 minutes.Implications: Funic KCl injection under direct visualization is a feasible method to induce fetal asystole at the time of intact dilation and evacuation. [ABSTRACT FROM AUTHOR]

Although only 1.3% of abortions in the United States are between 20 and 24 weeks' gestation, these procedures are associated with elevated risks of morbidity and mortality. Adequate cervical preparation before dilation and evacuation (D&E) at 20-24 weeks' gestation reduces procedural risk. For this gestational range, at least one day of cervical preparation with osmotic dilators is recommended before D&E. The use of overnight osmotic dilators alone is sufficient for most D&Es at 20-24 weeks' gestation. Dilapan-S® dilators require a shorter time to achieve maximum dilation, may be more effective than laminaria and may increase the likelihood of success on the first D&E attempt. The use of adjunctive mifepristone administered one-day pre-operatively at the time of osmotic dilator placement, should be considered because evidence demonstrates that it makes D&E subjectively easier at 20-24 weeks without increasing side effects. While older studies suggest that two-days of serial osmotic dilators provide greater dilation than one day of dilators, adjunctive mifepristone may be comparable to a second day of dilators. Adjunctive misoprostol administered on the day of D&E does not appear to affect initial cervical dilation and procedure time and compared with mifepristone is associated with more side effects, such as pain and nausea. Using overnight mifepristone and same-day misoprostol without osmotic dilators at 20-24 weeks' gestation lengthens D&E procedure time and appears to increase immediate complications, at least among less experienced providers. Some evidence shows the feasibility of same-day cervical preparation before D&E at 20-24 weeks using Dilapan-S® with adjunctive misoprostol or serial repeat dosing of misoprostol, but same-day preparation should be limited to providers with significant experience with these regimens. The Society of Family Planning recommends preoperative cervical preparation before D&E at 20-24 weeks' gestation. Further studies are needed to clarify the best means of preparing the cervix in order to minimize abortion complications and improve outcomes in this gestational range. [ABSTRACT FROM AUTHOR]

Kemeny's constant κ (G) of a connected undirected graph G can be interpreted as the expected transit time between two randomly chosen vertices for the Markov chain associated with G. In certain cases, inserting a new edge into G has the counter-intuitive effect of increasing the value of κ (G). In the current work we identify a large class of graphs exhibiting this "paradoxical" behavior – namely, those graphs having a pair of twin pendent vertices. We also investigate this phenomenon in the context of random graphs, showing that it occurs for almost all connected planar graphs. To establish these results, we make use of a connection between Kemeny's constant and the resistance distance of graphs. [ABSTRACT FROM AUTHOR]

In this paper, Special Relativity Search (SRS) is developed for solving engineering problems. The interaction of particles in a magnetic field is considered as an optimizer model of the SRS in which the magnetic field is the feasible search space and the particles in this field are the possible design vectors. Particles interaction is investigated using the Lorentz force, velocity and distance between particles. Charged particles that move in opposite directions produce an inverse force and repel each other while charged particles that move in the same direction attract each other. The special relativity theory is implemented in an applicable way to develop SRS. In SRS, using the angular frequency, centripetal force, and inverse Lorentz transformations, main equations of the algorithm are developed. The design variables are randomly selected as a candidate for optimal answers from the initial population and updated their position in each iteration. This process continues until the global optimum is obtained. In this paper, to validate the SRS performance in solving engineering problems, total twenty-nine CEC-2017 Boundary Constraint (BC) problems and 12 engineering problems are optimized. To evaluate the superiority of the SRS algorithm, the results are compared with other well-known metaheuristic methods. Friedman's test is also used to rank the best algorithm. The results show a good performance of the SRS in most problems with the lowest computational cost. [Display omitted] • Special Relativity Search is developed. • Lorentz inverse transformations, the phenomenon of length contraction, and time dilation are main steps. • The new algorithm is utilized to solve real-world mechanical and structural engineering problems. [ABSTRACT FROM AUTHOR]

Abstract Using a modified direct shear apparatus, an extensive experimental investigation is conducted into the influence of the inherent anisotropy of sand on the mobilization of the peak and critical state friction angles as well as the maximum dilation angle of the interfaces between an inherently anisotropic crushed sand and two woven geotextiles, one nonwoven geotextile, and one geomembrane. Experimental findings confirm that both peak and maximum dilation angles of sand-geosynthetic interfaces are affected from soil inherent anisotropy depending on the bedding plane inclination with respect to the shear plane. However, a unique critical state (residual) friction angle is attained for each interface type irrespective of the bedding plane inclination angle. Compiling results of a total of 141 tests, it is shown that a unique rule describes stress-dilation relationship of four different dense crushed sand-geosynthetic interfaces. The experimental data indicate that the ϕ p vs. θ and ψ max vs. θ curves are symmetrical with respect to θ = 90° for the sand-woven geotextile and sand-geomembrane interfaces. Finally, it is shown that a constitutive equation by Pietruszczak and Mroz (2001) can predict the variation of ϕ p with θ for the sand-woven geotextile and sand-geomembrane interfaces. [ABSTRACT FROM AUTHOR]

• The subjective duration of an auditory stimulus is veridical during saccades. • A synchronous sound reduces saccadic visual chronostasis magnitude. • The effects of the saccade and sound on visual time perception add linearly. The saccadic chronostasis illusion refers to the duration overestimation of the first visual stimulation after saccadic eye movement, which is also known as "stopped clock illusion." The present study investigated whether saccadic chronostasis would be observed in the auditory modality and whether the saccade-induced time dilation in the visual modality would be reduced by a synchronously presented sound. In each trial, a unisensory visual stimulus, unisensory sound, or bimodal audio-visual stimulus with a duration of 200–800 ms (probe stimulus) was presented at the saccade target location and temporally around the offset of the saccade, followed by a unisensory visual or auditory standard stimulus for a fixed 500 ms. Participants were required to identify which of the two stimuli (probe or standard) presented in the target modality (visual or auditory) was perceived as longer. The results showed that no saccadic chronostasis was observed in the auditory modality, regardless of whether the sound was presented alone or synchronously accompanied by a visual stimulus. Interestingly, the magnitude of the saccadic chronostasis illusion was reduced by the synchronously presented sound. Moreover, the combined effect of the saccade and sound on visual time perception fits well with the standard scalar model, and the weight of the cross-modal effect was higher than that of saccadic visual time dilation. These results suggest that sound dominates vision in time processing during saccades and linearly modulates saccadic chronostasis, which follows the Scalar Expectancy Theory. [ABSTRACT FROM AUTHOR]

There are only a few related studies focused on the steam assisted gravity drainage (SAGD) dilation start-up technology (termed as dilation start-up in this paper), especially with true triaxial stress physical modelling experiments in the laboratory. Therefore, in order to better understand the dilation start-up process, four large-scale (1050 mm × 410 mm × 410 mm) true triaxial experiments of SAGD start-up with dual horizontal wells were conducted for the first time by using the oil sands from the Xinjiang oilfield, northwest China. The dilation process characterized by temperature changes at different positions inside the experimental samples was monitored in real time. The performance differences between dilation start-up and conventional start-up were discussed in detail, and the effects of dilation pressure and dilation time on the dilation process were also studied. The experimental results indicate that dilation start-up can significantly reduce the well communication time between injector and producer, and enhance the range of dilation zone and improve the uniformity of dilation zone along the horizontal wellbores. Moreover, we find that dilation pressure is an essential factor influencing the dilation effect. The average communication parameter increases by 5% if dilation pressure increases by 10% whereas the standard deviation of communication parameter decreases. The evolution of dilation zone with time shows that long-time dilation prompts the uniform propagation of dilation zone along the horizontal wellbores. This study provides guidance for the optimization of SAGD dilation start-up in shallow heavy oil reservoirs. • Four large-scale true triaxial experiments of SAGD start-up with dual horizontal wells were conducted. • Dilation process characterized by temperature changes inside the samples was monitored in real time. • Effects of dilation pressure and dilation time on the SAGD dilation start-up were studied. [ABSTRACT FROM AUTHOR]

Background: Because nearly one-third of births in the United States are now achieved by cesarean delivery, comprising more than 1.27 million women each year, national organizations have recently published revised guidelines for the management of labor. These new guidelines stipulate that labor arrest should not be diagnosed unless ≥6 cm cervical dilatation has been reached or labor has been stimulated for at ≥6 hours.Objective: To determine the cervical dilatation and hours of labor stimulation prior to cesarean delivery for arrest of dilatation.Materials and Methods: Between January 1, 1999, andDecember 31, 2000, a prospective observational study of all primary cesarean deliveries was conducted at 13 university centers comprising the Eunice Kennedy Shriver National Institute for Child Health and Human Development, Maternal-Fetal Medicine Units Network. This secondary analysis includes all live-born, singleton, nonanomalous, cephalic gestations delivered by primary cesarean delivery at ≥37 weeks. A cesarean delivery was considered to have been performed for arrest of dilatation if the indication for the procedure was failure to progress, cephalopelvic disproportion, or failed induction. Augmentation was defined as stimulation after spontaneous labor had been previously diagnosed. Analysis included both the latent and active phases of labor. The active phase of labor was diagnosed when cervical dilatation was ≥4 cm in the presence of uterine contractions.Results: A total of 13,269 primary cesarean deliveries were available for analysis, 8,546 (65%) of which were performed for inadequate progress of labor with cervical dilatation recorded at the time of cesarean delivery. Of these cesarean deliveries for labor arrest, a total of 719 (8%) were performed in the latent phase of labor and 7827 (92%) were performed when cervical dilatation was ≥4 cm (active phase). Approximately two-thirds (n = =5876; 69%) received intrauterine pressure monitoring. A total of 5636 women (66% of those reaching the active phase of labor) had reached ≥6 cm cervical dilatation before cesarean delivery was performed. Moreover, 7440 (95%) of the 7827 women in active labor had ≥6 cm dilatation or had received labor stimulation ≥6 hours prior to cesarean delivery for arrest of dilatation.Conclusion: Women undergoing primary cesarean delivery for arrest of dilatation 15 years before the recommendations of the Obstetrics Care Consensus had received bona fide efforts to achieve adequate labor consistent with the recommendations of the Consensus. Because 95% of these women had ≥6 cm dilatation or had received labor stimulation ≥6 hours prior to cesarean delivery for arrest of dilatation, these new recommendations are unlikely to change the cesarean delivery rates. [ABSTRACT FROM AUTHOR]

Background: Recommendations on preventing primary cesarean delivery removed the previously defined time limits for latent labor (defined as ending at 6 cm) and urged clinicians to avoid cesarean delivery for labor abnormalities in the latent phase. However, relatively little is known about the implications of labor curve abnormalities from 4 to 6 cm and subsequent outcomes.Objective: To examine the association between length of time for dilation from 4 to 6 cm, delivery outcomes, and maternal and neonatal morbidity.Study Design: This is a secondary analysis of a prospective cohort study of patients at ≥37 weeks presenting in spontaneous or induced labor with a nonanomalous living singleton in vertex presentation. Patients with a history of cesarean delivery or who did not achieve 6-cm dilation were excluded. We used interval censored regression to determine the 90th percentile for dilation time from 4 to 6 cm and used logistic regression to estimate the odds ratios and 95% confidence intervals for adverse outcomes for patients above this cutoff percentile compared with those at or below. Analyses were adjusted for obesity, nulliparity, race, hypertension, diabetes, and type of labor (induced vs spontaneous/augmented). Outcomes included cesarean delivery, maternal morbidity (composite of postpartum fever, wound infection, hemorrhage), and neonatal morbidity (composite of neonatal death, hypothermic therapy, mechanical ventilation, respiratory distress, meconium aspiration syndrome, seizure, or treatment of sepsis). In addition, we created receiver operator characteristic curves to predict cesarean delivery, and maternal and neonatal morbidity based on time to dilate from 4 to 6 cm. The cutoff for time for each outcome was identified using the Youden index to maximize sensitivity and specificity, and test characteristics were computed.Results: There were 7355 patients eligible for analysis, 728 (10%) had dilation times from 4 to 6 cm >10.3 hours, which was the 90th percentile, and 6627 (90%) had dilation times ≤10.3 hours. Having dilation time from 4 to 6 cm above the 90th percentile (10.3 hours) was associated with cesarean delivery (adjusted odds ratio, 2.05; 95% confidence interval, 1.67-2.52), composite maternal morbidity (adjusted odds ratio, 1.48; 95% confidence interval, 1.10-2.00), and composite neonatal morbidity (adjusted odds ratio 1.92; 95% confidence interval 1.52-2.4). The area under the receiver operator characteristic curve for predicting cesarean delivery was 0.73 (95% confidence interval, 0.71-0.75). The test characteristics for the cutoff of 9.75 hours were sensitivity 68.3% (95% confidence interval, 64.8%-71.7%), specificity 66.2% (95% confidence interval, 55.0%-67.3%), positive predictive value 18.5% (95% confidence interval, 17.1%-20.0%), and negative predictive value 94.9% (95% confidence interval, 94.2%-95.5%). For composite maternal morbidity, the cutoff was 6.98 hours and the area under the curve was 0.62 (95% confidence interval, 0.59-0.65), whereas for composite neonatal morbidity it was 5.5 hours (area under the curve 0.69; 95% confidence interval, 0.67-0.71).Conclusions: Patients whose dilation time from 4 to 6 cm exceeds the 90th percentile have increased odds of cesarean delivery and postpartum complications. Prolonged dilation time has moderate predictive ability for adverse outcomes. Future studies should investigate at what point, if any, intervention is warranted during this period to reduce these risks. [ABSTRACT FROM AUTHOR]

[Display omitted] • An alternative scenario of the evolution of the Universe is proposed. • The absorption of light by cosmic dust causes opacity that counterbalances gravitational forces. • The theory predicts cyclic model of the expansion and contraction of the Universe. • The maximum redshift of the Universe is about 15–17. • The proposed model removes some tensions of the standard cosmological model. Recent observations indicate that the Universe is not transparent but partially opaque due to absorption of light by ambient cosmic dust. This implies that the current cosmological model valid for the transparent universe must be modified for the opaque universe. The paper studies a scenario of the evolution of the Universe when the cosmic opacity steeply rises with redshift, because the volume of the Universe was smaller and the cosmic dust density was higher in the previous epochs. In this case, the light-matter interactions become important, because cosmic opacity produces radiation pressure that counterbalances gravitational forces. The radiation pressure due to cosmic opacity is evaluated and incorporated into the Friedmann equations, which describe cosmic dynamics. The equations are based on the conformal FLRW metric and are consistent with observations of the cosmological redshift as well as time dilation. Using astronomical observations of basic cosmological parameters, the solution of the modified Friedmann equations is numerically modelled. The presented model predicts a cyclic expansion/contraction evolution of the Universe within a limited range of scale factors with no Big Bang. The redshift of the Universe with the minimum volume is about 15–17. The model avoids dark energy and removes several fundamental tensions of the standard cosmological model. In agreement with observations, the modified Friedmann equations predict the existence of very old mature galaxies at high redshifts and they do not limit the age of stars in the Universe. The new model is consistent with theory of cosmic microwave background as thermal radiation of cosmic dust. The paper demonstrates that considering light-matter interactions in cosmic dynamics is crucial and can lead to new cosmological models essentially different from the currently accepted ΛCDM model. [ABSTRACT FROM AUTHOR]

Using the Hodge decomposition on bounded domains the compressible Euler equations of gas dynamics are reformulated using a density weighted vorticity and dilatation as primary variables, together with the entropy and density. This formulation is an extension to compressible flows of the well-known vorticity-stream function formulation of the incompressible Euler equations. The Hamiltonian and associated Poisson bracket for this new formulation of the compressible Euler equations are derived and extensive use is made of differential forms to highlight the mathematical structure of the equations. In order to deal with domains with boundaries also the Stokes-Dirac structure and the port-Hamiltonian formulation of the Euler equations in density weighted vorticity and dilatation variables are obtained. [ABSTRACT FROM AUTHOR]

The perceived duration of a visual event is highly related to stimulus attributes. It is well known that a moving stimulus appears to last longer than a static one does. Previous studies have demonstrated that the time dilation in a moving stimulus can be influenced by perceived motion, rather than by mere physical motion, and that a faster motion appears to last longer than a slower one does. However, whether a top-down attentional set for the feature value can modulate the time dilation in a moving stimulus when two different visual patterns coexist within the same region of the visual field is still unknown. To test this, in Experiment 1, we presented a moving and a static random-dot pattern simultaneously within the same region, and instructed the observer to attend to one of these two patterns. The results demonstrate that perceived duration was longer when attention was directed to the moving, rather than static pattern, although both patterns physically coexisted at the same time and place and for the same duration. In Experiment 2, slow and/or fast moving patterns were presented at the same time and place, and again, feature-based attentional selection affected the perceived duration of the identical physical display. These results suggest that attention to a moving stimulus is an essential factor that determines the time dilation in a moving stimulus. This study revealed that feature-based attention, as opposed to location-based attention, plays an important role in motion-induced time dilation. [ABSTRACT FROM AUTHOR]

Abstract: The time scale for cooling of the gravitationally bound gaseous intracluster medium (ICM) is not determined by radiative processes alone. If the ICM is in quasi-hydrostatic equilibrium in the fixed gravitational field of the dark matter halo then energy losses incurred by the gravitational potential energy of the gas should also be taken into account. This “gravitational heating” has been known for a while using explicit solutions to the equations of motion. Here, we re-visit this effect by applying the virial theorem to gas in quasi-hydrostatic equilibrium in an external gravitational field, neglecting the gravity of the gas. For a standard NFW form of halo profiles and for a finite gas density, the response of the gas temperature to changes in the total energy is significantly delayed. The effective cooling time could be prolonged by more than an order of magnitude inside the scale radius of the halo. Gas lying at a distance twice the scale radius, has negative heat capacity so that the temperature increases as a result of energy losses. Although external heating (e.g. by AGN activity) is still required to explain the lack of cool ICM near the center, the analysis here may circumvent the need for heating in farther out regions where the effective cooling time could be prolonged to become larger than the cluster age and also explains the increase of temperature with radius in these regions. [Copyright &y& Elsevier]

Abstract: In this article we construct a tiny graviton matrix model for type IIB string theory on a plane-wave background with null dilaton. For the linear null dilaton case, we analyze its vacuum and the excitation spectrum around the vacuum, and discuss the time-dependent fuzzy three-sphere solutions and their evolution. It turns out that at very late time the non-Abelian fuzzy degrees of freedom disappear, which indicates the appearance of perturbative strings. [Copyright &y& Elsevier]

Abstract: With an appropriate combination of three Liouville-type dilaton potentials, we construct a new class of spinning magnetic dilaton string solutions which produces a longitudinal magnetic field in the background of anti-de Sitter spacetime. These solutions have no curvature singularity and no horizon, but have a conic geometry. We find that the spinning string has a net electric charge which is proportional to the rotation parameter. We present the suitable counterterm which removes the divergences of the action in the presence of dilaton potential. We also calculate the conserved quantities of the solutions by using the counterterm method. [Copyright &y& Elsevier]

Abstract: This paper studies the approximation of nonstationary signals from natural life systems in time–frequency plane using a type of four-parameter Gabor atoms. These four parameters, i.e. the dilation, chirprate, modulation and translation, have clear physical meanings and to optimize these parameters is an extremely difficult task. In this paper, a fast procedure is introduced without explicitly exploring these parameters over the continuous search space. Here, these four parameters together with a phase parameter for real signal are assigned with random values across their full ranges, creating a large library of candidate Gabor atoms. Then a fast algorithm is used to select atoms from the library that best approximate the nonstationary signal. The computational complexity of the method is only linearly related with the library size, the number of signal points and the number of used atoms. The proposed method is applied to several benchmark problems from life systems, including the bat signals, EEG signals and speech signals. The simulation results confirm its efficacy. [Copyright &y& Elsevier]

Abstract: The task of calculating operator dimensions in the planar limit of super-Yang–Mills theory can be vastly simplified by mapping the dilatation generator to the Hamiltonian of an integrable spin chain. The Bethe ansatz has been used in this context to compute the spectra of spin chains associated with various sectors of the theory which are known to decouple in the planar (large-) limit. These techniques are powerful at leading order in perturbation theory but become increasingly complicated beyond one loop in the ''t Hooft parameter , where spin chains typically acquire long-range (non-nearest-neighbor) interactions. In certain sectors of the theory, moreover, higher-loop Bethe ansätze do not even exist. We develop a virial expansion of the spin chain Hamiltonian as an alternative to the Bethe ansatz methodology, a method which simplifies the computation of dimensions of multi-impurity operators at higher loops in λ. We use these methods to extract previously reported numerical gauge theory predictions near the BMN limit for comparison with corresponding results on the string theory side of the AdS/CFT correspondence. For completeness, we compare our virial results with predictions that can be derived from current Bethe ansatz technology. [Copyright &y& Elsevier]

Internet addiction (IA) has been related to psychiatric problems such as ADHD. However, it is not known exactly how this relationship operates, although most research shows that both people with ADHD and IA have inhibitory control (IC) deficit. This study aimed to investigate whether IC mediates or moderates the relationship. 76 non-clinically diagnosed participants were recruited. They performed the Stroop task and completed the Young's Internet Addiction Test, Adult ADHD Self-Report Scale Symptom Checklist and a Demographic Information Form. Consistent with previous research, the results show that while total ADHD/inattention was correlated with IA, hyperactivity/impulsivity was not. In contrast with some previous research, Stroop task performance (measured via reaction times and pupil dilation) did not differ between low and high IA groups, nor low and high inattention groups. Despite neither inattention nor IA between associated with IC impairments, the relationship between inattention and IA was shown to be moderated by Stroop task performance in that the relationship was present mainly in those who experience high and moderate IC deficits. This finding could have implications for both ADHD and IA at higher levels of severity and could help guide prevention and treatment options in those most vulnerable to IA. [ABSTRACT FROM AUTHOR]