Slow Motion Research Articles

Evidence for Complex Dynamics in Glassy Fast Ion Conductors: The Case of Sodium Thiosilicates.

Classical molecular dynamics is used to study the dynamics of alkali ions in a promising fast ion conductor glass system, i.e., Na2S-SiS2. Diffusion in such thiosilicates is found to display various salient features of alkali silicates, i.e., channel-like diffusion with typical length scales emerging as the temperature is decreased to the glassy state, and Arrhenius behavior for both Na ion diffusivity and calculated conductivity. The dynamics appears, however, to be largely heterogeneous as manifested by fast and slow Na ion motion at intermediate times, both in the high-temperature liquid and in the glassy state. In the former, a diffusion-limited regime is found due to the increased motion of the network-forming species that limits the Na ion dynamics, whereas at low temperatures, the typical dynamical heterogeneities are recovered as observed close to the glass transition.

Slow motion of a sphere near a sinusoidal surface

Particle motion near non-plane surfaces can exhibit intricate hydrodynamics, making it an attractive tool for manipulating particles in microfluidic devices. To understand the underlying physics, this work investigates the Stokesian dynamics of a sphere near a sinusoidal surface, using a combination of perturbation analysis and boundary element simulation. The Lorentz reciprocal theorem is employed to solve the particle mobility near a small-amplitude surface. Compared with a plane wall, the curved topography induces additional translation and rotation velocity components, with the direction depending on the location of the sphere and the wavelength of the surface. At a fixed distance from the surface, the longitudinal and vertical mobilities of the sphere are strongly affected by the wavelength and amplitude of the surface, whereas its transverse mobility is only mildly influenced. When a sphere settles perpendicular to a sinusoidal surface, the far-field hydrodynamic effect drives the particle towards the local hill, while the near-field effect attracts the particle to the valley. These results provide valuable insights into the particle motion near surfaces with complex geometry.

Khronometric Theories of Modified Newtonian Dynamics

In 2011 Blanchet and Marsat suggested a fully relativistic version of Milgrom's modified Newtonian dynamics in which the dynamical degrees of freedom consist of the spacetime metric and a foliation of spacetime, the khronon field. This theory is simpler than the alternative relativistic formulations. We show that the theory has a consistent nonrelativistic or slow-motion limit. Blanchet and Marsat showed that in the slow motion limit, the theory reproduces stationary solutions of modified Newtonian dynamics. We show that these solutions are stable to khronon perturbations in the low acceleration regime, for the cases of spherical, cylindrical, and planar symmetry. For nonstationary systems in the low acceleration regime, we show that the khronon field generally gives an order unity correction to the modified Newtonian dynamics. In particular, there will be an order unity correction to the MOND version of Kepler's third law, potentially relevant to ongoing efforts to test MOND using GAIA observations of wide binaries.

Phosphoproteome analyses pinpoint the F-box protein SLOW MOTION as a regulator of warm temperature-mediated hypocotyl growth in Arabidopsis.

Hypocotyl elongation is controlled by several signals and is a major characteristic of plants growing in darkness or under warm temperature. While already several molecular mechanisms associated with this process are known, protein degradation and associated E3 ligases have hardly been studied in the context of warm temperature. In a time-course phosphoproteome analysis on Arabidopsis seedlings exposed to control or warm ambient temperature, we observed reduced levels of diverse proteins over time, which could be due to transcription, translation, and/or degradation. In addition, we observed differential phosphorylation of the LRR F-box protein SLOMO MOTION (SLOMO) at two serine residues. We demonstrate that SLOMO is a negative regulator of hypocotyl growth, also under warm temperature conditions, and protein-protein interaction studies revealed possible interactors of SLOMO, such as MKK5, DWF1, and NCED4. We identified DWF1 as a likely SLOMO substrate and a regulator of warm temperature-mediated hypocotyl growth. We propose that warm temperature-mediated regulation of SLOMO activity controls the abundance of hypocotyl growth regulators, such as DWF1, through ubiquitin-mediated degradation.

Researches advanced in the SLAM for dynamic environment

Simultaneous Localization and Mapping (SLAM) has always been a popular topic in the computer vision community, as it seeks to forecast the location of agents and use sensors to detect their surroundings in order to construct maps and perform navigation. The majority of SLAM algorithms assume that objects in the environment are immobile or in slow motion, whereas the SLAM system in a dynamic world remains an unanswered question. When constructing a 3D point cloud map by sequentially accumulating scanning data, dynamic objects typically leave undesirable traces in the map. The traces of these dynamic items operate as impediments, hindering the positioning and navigation performance of mobile vehicles. In this work, we discuss the most recent advancements in SLAM in a dynamic context. Specifically, this paper examines three characteristics of the most significant negative effects that the dynamic environment has on SLAM. Then, according to the dynamic degree, solutions are presented for various dynamic items, including the design concept, basic framework, advantages, and disadvantages. We conclude by discussing the existing research difficulties in the subject of dynamic SLAM and its projected development path.

Coseismic and Tectonic Time-Scale Deformations of an Island Arc Based on Studies of East Coast of Kamchatka Peninsula (Far East, Russia)

Geologic structure of the late Holocene accumulative marine terrace on the coast of Kamchatka Bay (Kamchatka Peninsula) has been studied. The ages and relative hypsometric position of beach ridges composing the terrace allowed us to identify two types of vertical movements of the coast: periodic fast (coseismic) and slow time-scale uplift or subsidence. Large-amplitude vertical coseismic movements (up to 1‒2 meters) occur on average once in about 1200‒1300 years, and slow movements occur at an average rate from a fraction of a millimeter to about 2 mm per year. Coseismic motions represent relaxation of elastic deformations accumulated during the interseismic interval of the seismic cycle, neither exceed them nor accumulate. Slow motions set the general trend of vertical deformations of the coast. It is assumed that the subsiding central parts of the eastern bays of Kamchatka Peninsula (Avachinsky, Kronotsky and Kamchatsky) and depressions between the eastern peninsulas (Kronotsky, Shipunsky) and the main massif of Kamchatka form an arc-parallel extension zone, which is nearest to the deep-water trench, and that extension is caused by the migration of the subducted part of the Pacific plate toward the Pacific Ocean. Under the eastern Shipunsky and Kronotsky peninsulas, the arc-normal extension of the earth’s crust of the Kamchatka segment of the Kuril-Kamchatka island arc is replaced by a zone of transverse compression.

Eruption of prominence initiated by loss of equilibrium: multipoint observations

ABSTRACT Using the SDO/AIA, SOHO/LASCO, STEREO/SECCHI, and ground-based H α, radio observations, we studied a prominence eruption (PE) from the western limb that occurred on 2013 December 4. PE is associated with a moderate coronal mass ejection (CME) and GOES class C4.7 flare. Before a couple of days, the prominence pre-existed as an inverse-S shaped filament lying above fragmented opposite polarities between two active regions. Initially, the prominence appears as kinked or writhed as observed from different vantage points. From a careful study of magnetic field observations, we infer that the flux emergence at one leg of the prominence causes the loss of equilibrium which then initiates the slow upward motion of the prominence followed by onset of the eruption at a projected height of 35 Mm. The fast rise motion is also in synchronization with the flare impulsive phase but the average acceleration is quite small (150 ms−2) compared to strong flare cases. In the LASCO field of view (FOV), the CME continues to accelerate at 3 ms−2 attaining a speed of 450 km s−1 at 16 R⊙. In the extended STEREO-A FOV upto 38 R⊙, the CME decelerates 0.82 m s−2. The PE launched type III bursts delayed by 14 min with respect to the flare peak time (04:58 UT). Since the prominence is lying in the fragmented polarities, it is likely that the sheared arcade has little contribution to the poloidal flux of the rising magnetic flux rope and subsequently weak flare is recorded. This study of PE emphasizes the influence of the magnetic reconnection on the CME speed, launch of type II, III burst, and the CME propagation distance farther away from the Sun.

Book Review: The Creed in Slow Motion

Book Review: The Creed in Slow Motion

Anisotropic dynamics of an interfacial enzyme active site observed using tethered substrate analogs and ultrafast 2D IR spectroscopy.

Enzymes accelerate the rates of biomolecular reactions by many orders of magnitude compared to bulk solution, and it is widely understood that this catalytic effect arises from a combination of polar pre-organization and electrostatic transition state stabilization. A number of recent reports have also implicated ultrafast (femtosecond-picosecond) timescale motions in enzymatic activity. However, complications arising from spatially-distributed disorder, the occurrence of multiple substrate binding modes, and the influence of hydration dynamics on solvent-exposed active sites still confound many experimental studies. Here we use ultrafast two-dimensional infrared (2D IR) spectroscopy and covalently-tethered substrate analogs to examine dynamical properties of the promiscuous Pyrococcus horikoshii ene-reductase (PhENR) active site in two binding configurations mimicking proposed "inactive" and "reactive" Michaelis complexes. Spectral diffusion measurements of aryl-nitrile substrate analogs reveal an end-to-end tradeoff between fast (sub-ps) and slow (>5ps) motions. Fermi resonant aryl-azide analogs that sense interactions of coupled oscillators are described. Lineshape and quantum beat analyses of these probes reveal characteristics that correlate with aryl-nitrile frequency fluctuation correlation functions parameters, demonstrating that this anisotropy is an intrinsic property of the water-exposed active site, where countervailing gradients of fast dynamics and disorder in the reactant ground state are maintained near the hydration interface. Our results suggest several plausible factors leading to state-selective rate enhancement and promiscuity in PhENR. This study also highlights a strategy to detect perturbations to vibrational modes outside the transparent window of the mid-IR spectrum, which may be extended to other macromolecular systems.

A Highly Ordered Nitroxide Side Chain for Distance Mapping and Monitoring Slow Structural Fluctuations in Proteins.

The online version contains supplementary material available at 10.1007/s00723-023-01618-8.

Weather Underground: Warming underneath cities is weakening buildings in slow motion.

Weather Underground: Warming underneath cities is weakening buildings in slow motion.

Voltage-dependent bundle motion in mammalian auditory hair cells

Auditory hair cells have bundles of protrusions on their surface held together by proteinaceous links. Sound-induced vibrations deflect these bundles, transferring force through the links to open nearby mechanically sensitive ion channels and providing our sensation of sound. An increase in bundle compliance caused by channel gating can also be detected as motion. The channels open during depolarization and the bundle moves rapidly toward shorter stereocilia, followed by a larger but slower movement toward the taller stereocilia. To determine how voltage changes affect mammalian inner hair cell (IHC) bundles, we used whole cell patch clamp and high-speed imaging to apply electrical stimulation and measure bundle motion. We found two components in the motions of freestanding IHC bundles in response to depolarization, a fast offset away from the tallest row and a slower movement back toward the tallest row. Like in turtles, the slower motion was sensitive to channel block and suggested ion flux, particularly calcium, played a role. Our findings show IHCs can rapidly respond to changes in the bundle setpoint without ion influx. This work improves our understanding of the mechano-electrical transduction process and helps address the controversial role of calcium in regulating the channel current response.

Altered Gait in Charcot Neuropathic Mice: A Kinematic Analysis

Category: Diabetes; Hindfoot Introduction/Purpose: Charcot arthropathy is known to cause neurodegenerative as well as physical skeletal changes that can affect gait. A verified model of inducing Charcot arthropathy in mouse hindlegs exists, but clinical data has yet to be gathered from this model. This is a pilot study with the purpose of gathering clinical data on mouse gait and joint reactive forces that occur over time as a result of Charcot arthropathy utilizing MatLab software. Methods: Eleven wild-type 25-week-old C57BL/6J were included in this study. Group A (n= 6) was fed a high-fat 60% kcal diet starting at the age of 6 weeks and underwent a verified running protocol to induce microtrauma leading to hind-paw Charcot-type arthropathy. Sensory testing and fasting blood glucose levels confirmed the presence of hyperglycemia and neuropathy in Group A. Group B (n= 5) was fed a normal diet and did not complete a running protocol. At week 0 and week 16 of the study, brightly colored dots were placed on mice hindlimbs to mark the hip, knee, ankle, and tarsal joints. The mice were placed on the treadmill at a constant speed of 10 m/sec and were recorded in slow motion for 2-3 full gait cycles. MATLAB was used to measure gait angles and coordinates in space by following the corresponding colored dot for each joint on the mouse (Figure 1). Results: The control mice did not have significant changes in range of motion of the knee, ankle, or midfoot while walking between weeks 0 and 16. In contrast, the mice fed a high-fat diet had statistically significant differences in ankle range of motion (p=0.0275), nearly significant differences in knee range of motion (p=0.0991), and insignificant differences in midfoot range of motion between weeks 0 and 16. In addition, the differences between range of motion of the knee of the control vs. C57BL/6J mice were significantly different between groups at both weeks 0 (p=0.0016) and 16 (p=0.0201). In the ankle, the difference was statistically significant at week 0 (p=0.0275) but not week 16 (p=0.7066), presumably due to a large standard deviation in ankle range of motion. Conclusion: Results of this gait analysis indicate that mice with Charcot-like arthropathic changes demonstrated gait differences that affected the range of motion of the knees and ankles of the mice, but not the midfoot. These changes could be due to the neuropathic abnormalities induced in mouse feet that would cause gait changes. Future studies will include a larger sample size of mice with gait analysis done at intermediate time points to further quantify how gait changes over time with Charcot arthropathy.

Free Energy Simulations of Receptor-Binding Domain Opening of the SARS-CoV-2 Spike Indicate a Barrierless Transition with Slow Conformational Motions.

Infection by sarbecoviruses begins with the attachment of the homotrimeric viral "spike" protein to the angiotensin-converting enzyme 2 receptor on the surface of mammalian cells. This requires one or more receptor-binding domains (RBDs) to be in the open (up) position. Here, we present the results of long molecular dynamics simulations with umbrella sampling (US) to compute a one-dimensional free energy profile of RBD opening/closing and the associated transition times. After ≃3.58μs of simulation time per US window (∼229 μs in total), which was required to approach trajectory decorrelation, the computed free energy profile was found to be without large barriers. This suggests that the RBD diffuses between the open and closed positions without significant energetic hindrance. This interpretation appears consistent with experiments but is at odds with some previous simulations. Modeling the RBD motion as diffusive dynamics along the computed free energy profile, we find that the overall time required for the transition is only about 2 μs, which is 5 orders of magnitude shorter than experimentally measured transition times. We speculate that the most likely reason for the transition time mismatch is our use of very short glycans, which was required to make the simulations performed here feasible. Despite the long simulation times, the final free energy profile is not fully converged with statistical errors of ≃1.16 kcal/mol, which were found to be consistent with the slow time decay in the autocorrelation of the conformational motions of the protein. The simulation lengths that would be required to obtain fully converged results remain unknown, but the present calculations would benefit from at least an order-of-magnitude extension.

Penerapan Media Pembelajaran Slow Motion Terhadap Hasil Belajar Roll Depan

The world of education is not far from teaching and learning activities. Educators play an important role in the success of the learning process. The use of learning media has a role during the learning process. The use of appropriate media can improve student learning outcomes. This study aims to determine the effect of slow motion learning media on forward roll learning outcomes. This research is a quantitative descriptive research in the form of a quasi-experimental. The population in this study is all classes of V at SDN Balonggabus with the sample used, namely 31 students. This research will be conducted 4 times. The data collection technique used is the learning achievement test instrument. The analysis technique used is descriptive, normality test, and hypothesis testing to prove the influence of learning media on student learning outcomes. Based on the results of the analysis, the results show that there is influence as evidenced by the results of the hypothesis test of 0.00, which means <0.05. So it can be concluded that there is a significant influence of the application of slow motion learning media on learning outcomes of forward roll.

Axial-lateral-torsional coupling nonlinear vibration of riserless drill-string considering both seawater and stratum parts

Riserless drilling has the obvious advantages of small platform load bearing and short well construction period because it discards the bulky conventional riser. However, because the drill-string is directly exposed to seawater, its dynamic behavior is extremely complex, which has an important impact on the safety and efficiency of drilling operations. Using the energy method and microelement method, an axial-lateral-torsional (ALT) coupling nonlinear vibration model of deepwater riserless drill-string considering both seawater and stratum sections is established. The model takes into account the platform heaving and slow drift motion, wind and ocean current, tidal current, wave load, wellbore contact, bit-rock interaction and seawater formation interaction. A bi-directional coupling scheme is proposed to obtain a good model solving efficiency. Using torsional vibration model results and field test data, the effectiveness of the model is presented in detail from the qualitative and quantitative aspects. The developed model and calculation program are used to analyze the dynamic behavior of a typical deep-water riserless drillings. The work in this paper can provide an effective analysis method and theoretical guidance for riserless drill-string design.

Flexible Patterned Electrohydrodynamic Jet Printing Using Orthogonal Deflection Electrodes.

Electrohydrodynamic jet (E-Jet) printing technology provides unmatched advantages in the fabrication of patterned micro/nanostructures. However, the rapid jets generated during printing can lead to localized droplet accumulation on complex structures due to the relatively slow motion control achieved with motorized translation stages, resulting in distorted patterns. To address this challenge, we introduce two jet-deflecting electrodes orthogonally placed on each other, which can rapidly change the electric field in the vicinity of the jet and thus flexibly adjust the flight trajectory of the fast jet to avoid the region where droplets have been deposited. In this way, the jet droplets are precisely controlled to generate high-fidelity microstructures with arbitrary predefined patterns on the stationary substrate. The maximum deflection distance of the jet droplets reaches several hundred microns. Furthermore, the positioning error of the printed structure is less than 3%. Moreover, we successfully obtained a diverse range of complex patterns by combining this technique with stage motion. This innovative printing technology not only enables the fabrication of complex patterned structures with high fidelity but also opens up exciting possibilities for new applications that require complete control of fast droplet positioning.

Effects of periodic parametric damping and amplitude-modulated signal on vibrational resonance and torus-doubling bifurcations occurrence in an asymmetric mixed Rayleigh-Liénard oscillator

This research paper examines the effects of periodic parametric damping and amplitude-modulated signal on vibrational resonance and the occurrence of torus-doubling bifurcations in an asymmetric mixed Rayleigh-Liénard oscillator. The method of direct separation of the slow and fast motions is used to derive the approximate theoretical expression of response amplitude at the low frequency. The obtained results show that the presence of periodic parametric damping induces in the system multiple resonance peaks when the low frequency is varied. Moreover, the increase of carrier amplitude modulated increases or decreases the maximum amplitude value in certain range of the low frequency. However, when the periodic parametric damping coefficient is varied, one resonance peak occurs and the maximum amplitude value increases when the carrier amplitude modulated increases. The theoretical and direct numerical predictions have shown a fairly satisfactory agreement. On the other hand, the global dynamical changes of the system are numerically examined in context of vibrational resonance. It is found that, the system displays many torus attractors of different topologies, torus-doubling bifurcations, reverse torus-doubling bifurcations and torus-chaos. These observations are illustrated by plotting the phase portraits and their corresponding Poincaré maps.

Slow motion medium for broadband lens antennas based on corrugated metal surfaces

A slowing medium based on parallel corrugated metal surfaces. The study of the moderating properties of the medium was carried out using numerical method in the Ansys HFSS software environment. It is shown that the medium has a strong spatial natural and weak frequency dispersion. The latter circumstance allows it to be used in as a material for broadband lenses of the VHF-microwave ranges of electromagnetic waves. As an example of such use, a lens-based antenna was synthesized and analyzed Mikaelyan.

Surprising Effects of Rocking Motion on Leishmania tarentolae Behavior in Culture and Implications for Cell Stress

Leishmania are an understudied genus of parasitic protozoans causing significant health problems for people, particularly in tropical climates. To better understand the growth of Leishmania and potential drug sensitivity implications, the effects of motion on cells grown in vitro were probed. Using a stock Leishmania tarentolae cell culture, cells were placed in 10 mL of a Brain–Heart Infusion medium in either a non-moving (static) environment or on a flat platform of one of two lab rockers (set at a minimal speed) in a dark environment for 13 days. Also, the addition of 0.5 M of L-Proline was evaluated. Microscopy, cell clumping, cell viability, and secreted acid phosphatase (SAP) activity data were collected. Results show that a constant slow rocking motion changed cell growth, clumping behavior, and detectable SAP activity relative to the no-motion cultures, but this change was dependent on which rocker was used, indicating a complexity in the growth of these cells in culture. Thus, continuous motion affects the stresses placed on the cells during a growth curve under some conditions. The implications of this study lead to questions about the effects of motion on the efficacy of pharmaceutical testing in vitro. Further study of the effects of motion on Leishmania is important.