Frequency Of Jumps Research Articles

IDENTIFICATION OF JUMPING ACTIVITY IN VOLLEYBALL BY USING ACCELEROMETER

BackgroundIn volleyball, training and match exposure is a risk factor for developing patellar tendinopathy which is known as jumper's knee. The frequency of jumping is an indicator of the intensity...

Rearing substrate and space allowance influences locomotor play behaviour of dairy calves in an arena test

The aim of this study was to investigate the effect of rearing substrate and space allowance in the home environment on the motivation of dairy calves to perform locomotor play in an arena test. At 1wk of age, 72 calves were moved into one of 18 experimental pens (n=4 calves/pen) where they remained until 6wk of age. Half of the pens had floors covered with stones (ST) and the other half were covered with sawdust (SD). For each substrate type, calves were reared at one of three space allowances: 1.0, 1.5 or 2.0m2/calf. Behaviour was video recorded continuously for 24h in the home environment at 4 and 6wk of age. Calves were tested individually in an arena test at 3 and 6wk of age, where behaviour was recorded for 20min. The arena floor was covered in wood chip. Running duration and the frequency of running, jumping, kicking and bucking were scored continuously and used as measures of locomotor play. At 4 and 6wk of age in the home environment, calves reared on ST spent less (P<0.05) time walking than calves reared on SD and calves reared at 1.0m2/calf spent less time (P<0.05) walking than calves reared at 1.5 or 2.0m2/calf. However, substrate type and space allowance did not affect (P>0.05) time calves spent running in the home environment. In the test arena, calves reared on ST ran more at 3 (1.7 and 1.5±0.05 square-root transformed values, ST and SD respectively, P=0.001) and 6 (1.4 and 1.2±0.08 square-root transformed values, ST and SD respectively, P=0.035) wk of age than calves reared on SD. At 3wk of age, calves reared at 1.0m2/calf spent more (P=0.016) time running than calves reared at 2.0 m2/calf (1.7, 1.6 and 1.5±0.06 square-root transformed values, 1.0, 1.5 and 2.0m2/calf respectively, P=0.022) in the test arena. Furthermore, time spent running in the home pen was positively correlated with running duration in the arena test irrespective of substrate type (ST: r=0.35, P=0.003 and SD: r=0.32, P=0.008) and space allowance (1.0m2/calf: r=0.42, P=0.004; 1.5m2/calf: r=0.28, P=0.054; 2.0m2/calf: r=0.25, P=0.095). Overall, our results suggest that different housing conditions (rearing substrate and space allowance) can affect the motivation of calves to perform locomotor play in an arena test, however the stimuli associated with this increased motivation to play remains unclear.

Simulation of nitrogen diffusion in Ni vis-à-vis Fe – Identification of better structural material for neutron detectors

Inconel 600, a Ni-based alloy was considered as a possible replacement for austenitic stainless steels for service at high temperatures in nitrogen containing atmosphere of the neutron detector. To obtain a fundamental understanding of the differences in the diffusivity of nitrogen in pure Fe and Ni lattices, molecular dynamics simulations were carried out. Based on the simulation of nitrogen trajectories in the temperature range of 1200–1400K, pre-exponential factor, activation energy and jumping frequency were calculated and compared for fcc Ni and Fe. MD simulations confirmed that rate of diffusion of nitrogen is lower in Ni when compared to Fe, suggesting the replacement of austenitic steel with Inconel 600 for better performance of the detectors.

Vertical dynamics of a pantograph carbon-strip suspension under stochastic contact-force excitation

In electric trains, a pantograph is mounted on the roof of the train to collect power through contact with an overhead catenary wire. The carbon-strip suspension of a pantograph, along which contact with the catenary occurs, is subjected to harmonic and stochastic contact-force excitations. In this paper, vertical dynamics of the carbon-strip suspension is studied with an aim of improving the reliability and safety of running trains. A single-degree-of-freedom model of the carbon-strip suspension with nonlinear stiffness is developed using parameter values of the DSA X pantograph. Through stochastic averaging, a Fokker–Planck–Kolmogorov equation governing the stationary response of the carbon-strip suspension is set up. Based on the transition probability density of the stationary response, it is found that random jumps and bifurcations in the carbon-strip motion can occur. The possibility of motion bifurcations and the frequency of random jumps warrant consideration in advanced design of carbon-strip suspensions.

Prediction of solute diffusivity in Al assisted by first-principles molecular dynamics

Ab initio calculations of the solid-state diffusivity of solute atoms in bulk aluminium have previously been based on transition state theory (TST), employing transition state searches and systematic assessments of single jumps together with appropriate models of jump frequencies and correlation factors like the five-frequency model. This work compared TST benchmark predictions of diffusivities with first-principles molecular dynamics (FPMD). The TST calculations were performed at unprecedented high precision, including the temperature dependent entropy of vacancy formation which has not been included in previous studies of diffusion in Al; this led to improved agreement with experimental data. It was furthermore demonstrated that FPMD can yield sufficient statistics to predict the frequency of single jumps, and FPMD was used to successfully predict the macroscopic diffusivity of Si in Al. The latter is not possible in systems with higher activation energies, but it was demonstrated that FPMD in such cases can identify which jumps are prevalent for a given defect configuration. Thus, information from FPMD can be used to simplify the calculation of correlation terms, prefactors and effective transition barriers with TST significantly. This can be particularly important for the study of more complicated defect configurations, where the number of distinct jumps rapidly increases to be intractable by systematic methods.

Jumping behavior of the springtail Folsomia candida as a novel soil quality indicator in metal-contaminated soils

This study validates that the jumping ability of the springtail Folsomia candida may be used to evaluate the soil quality of Cu and Ni polluted sites. The jumping ability of the springtail F. candida exposed to metal-contaminated soil was evaluated by observing the frequency, distance, and direction of jumping. The jumping assay was performed using individuals that survived a chronic soil test, in which jumping was induced by chemical stress (methyl alcohol). The chronic soil test generated expected adverse effects on springtail reproduction and survival rates. In the jumping assay, the control group exhibited high jumping frequency and variable escape maneuvers. In contrast, the exposed group exhibited a significant decrease in jumping ability (with some individuals being unable to jump) and performed very simple escape maneuvers. The toxicity indicator values of the jumping assay were comparable to reproduction data, and were more sensitive compared to survival data. To the best of our knowledge, this is the first study to assess the jumping ability of F. candida on metal-contaminated soils. The evaluation of jumping activity may represent a viable field screening technique for soil quality.

Acute ethanol exposure induces behavioural differences in two zebrafish (Danio rerio) strains: A time course analysis

The zebrafish has been proposed as a model organism to study genetic effects influencing behaviour and also as a tool with which the mechanisms of the action of alcohol (ethanol or EtOH) in the vertebrate brain may be investigated. In the current study we exposed zebrafish from two genetically distinct strains (WIK and TU) to a computer animated image of a natural predator of this species, the Indian leaf fish. We measured the subjects’ behavioural responses in the presence of different acute doses of alcohol (0.00, 0.25, 0.50, and 1.00% vol/vol) using an observation based event-recording method. We found fish of both strains to exhibit an atypical predator inspection response during the presentation of the animated predator image coupled with a classical fear response, increased jumping frequency. We found numerous alcohol induced behavioural changes and more importantly also revealed alcohol induced strain dependent changes as well, including different dose-response trajectories for WIK vs. TU in predator inspection response, general swimming activity, location of swimming (top vs. bottom half of the tank) and freezing. The results suggest that zebrafish of the TU strain may be more tolerant at least to lower doses of alcohol as compared to WIK. The characterization of strain differences in zebrafish will aid the identification of possible molecular mechanisms involved in alcohol's actions in the vertebrate brain.

Choice of perch characteristics by laying hens in cages with different group size and perching behaviours

Provision of perches in cages could improve behaviour and physical conditions of laying hens. This study was conducted to investigate the choice of perch characteristics (shape, width, material and height) by caged hens under different group size, and to understand the choice by the perching behaviours of hens. This study was consisted of four trials: perch shape (rectangular and round in cross section), width (3.0cm and 5.0cm), material (steel, wood and plastic) and height (10cm, 20cm, 30cm and 40cm) tests. In each trial, 390 Hyline Brown laying hens were used and randomly allocated to three treatments: individual group (G1), group of four hens (G4), and group of eight hens (G8), respectively. There were 30 replicates in each group. The hens in G1, G4 and G8 groups were put in the test cages in which designed perches were simultaneously provided and tested after four habituating days. Hens’ behaviours were recorded using cameras at the following periods: 8:00–10:00; 14:00–16:00; 19:00–21:00 and 23:30–0:30 on the fifth and seventh day. The behaviours of the hens were analyzed, and the hens’ positions on test perches during mid-night were recorded. The results showed that, the rectangular perches were chosen more than round perches in all groups (p<0.01), and comforting behaviour was performed more (p<0.05) on the rectangular perches than on the round ones. The 3.0cm wide perches were highly preferred to 5.0cm perches in G1 and G4 groups (p<0.05). The hens on the 5.0cm wide perches performed more pecking (p<0.01). Besides, the wood perches were chosen more than steel or plastic perches in all groups (p<0.05). The hens chose 20cm high perches most in G1 group and G4 groups (p<0.05), but 10cm high most in G8 groups (p<0.01). The perching behaviour was significantly affected by perch height (p<0.05). Besides, the frequency of jumping, pecking and comforting were significantly affected by group size (p<0.05). Consequently, we recommend that the rectangular wood perches of 3.0cm wide and 20cm high may be suitable for the commercial furnished cages that the height is not lower than 100cm.

Recursive eigenvalue search algorithm for transfer matrix method of linear flexible multibody systems

The transfer matrix method is a rather unusual strategy of modeling linear multibody systems, however, it is able to elegantly model systems including both discrete and continuous elements and to solve such kind of problems with any precision required. This is achieved by transforming differential to algebraic equations and summarizing all system information in an overall system of linear equations independent of the degrees of freedom. Nontrivial solutions representing vibration modes then require the coefficient matrix to be singular. Thus, the precision of solutions is associated with the ability of finding zeros for the determinants of these coefficient matrices, which may be nonlinear or transcendental, real or complex functions of natural vibration frequencies or complex eigenvalues. The paper reduces the zero search to a minimization problem and suggests two simple, but robust algorithms which are much more efficient than direct enumeration. Further, the problem of noisy determinant computation is addressed and the complex transfer matrix of a rod for damped vibrations is derived. Three basic examples serve for demonstrating the concept and for showing the robustness of the proposed approach. For a rod-damper system, the solution with jumping frequencies for a critical damping value can be proven analytically.

On Solar-Wind Electron Heating at Large Solar Distances

We study the temperature of electrons advected with the solar wind to large solar distances far beyond 1 AU. Almost nothing is known about the thermodynamics of these electrons from in-situ plasma observations at these distances, and usually it is tacitly assumed that electrons, due to adiabatic behaviour and vanishing heat conduction, rapidly cool off to very low temperatures at larger distances. In this article we show, however, that electrons on their way to large distances undergo non-adiabatic interactions with travelling shocks and solar-wind bulk-velocity jumps and thereby are appreciably heated. Examining this heating process on an average statistical basis, we find that solar-wind electrons first cool down to a temperature minimum, which depending on the occurrence frequency of bulk velocity jumps is located between 3 and 6 AU, but beyond this the lowest electron temperature again starts to increase with increasing solar distance, finally achieving temperatures of about 7×104 K to 7×105 K at the location of the termination shock. Hence these electrons are unexpectedly shown to play an important dynamical role in structuring this shock and in determining the downstream plasma properties.

ON THE INTRINSIC CONTINUUM LINEAR POLARIZATION OF CLASSICAL Be STARS: THE EFFECTS OF METALLICITY AND ONE-ARMED DENSITY PERTURBATIONS

We report on the effects of two disk properties on the continuum linear polarization signature of classical Be stars. First, we investigate the effect of including metallicity in computing the thermal structure of the circumstellar gas on the resulting polarimetric Balmer jump. The Balmer jump is a distinguishing feature of the polarization signature in these objects and, as such, can be used as a tool for differentiating classical Be stars from similar Hα-emitters identified through conventional photometric techniques. We find that although low-metallicity environments will have hotter disk temperatures on average, the temperature change alone cannot account for the discrepancy in the frequency of Balmer jumps between low-metallicity and solar-metallicity stellar populations. Second, we investigate the effect of including a global one-armed oscillation in the gas density distribution of the modeled disk. We find that a non-axisymmetric perturbation pattern yields discernible variations in the predicted polarization level. If these density oscillations are present in the inner region of classical Be star disks, the polarimetric variations should produce a periodic signature which can help characterize the dynamical nature of the gas near the star.

Which Continuous-Time Model is Most Appropriate for Exchange Rates?

This paper determines the most appropriate ways to model diffusion and jump features of exchange rates. Simulations show that intraday periodicity in volatility prevents conventional tests from accurately identifying the frequency and location of jumps. We propose a two-stage correction for this periodicity that improves the properties of the test statistics. The most plausible model for 1-minute exchange rate data features Brownian motion and Poisson jumps but not infinite activity jumps. We also show that microstructure noise biases but does not unduly impair the statistical tests for jumps and diffusion behavior in finite samples.

Theoretical and experimental analyses of a nonlinear magnetic vibration isolator with quasi-zero-stiffness characteristic

This paper presents a nonlinear magnetic low-frequency vibration isolator designed with the characteristic of quasi-zero stiffness (QZS). An approximate expression of the magnet repulsive force is proposed and a unique analytical relationship between the stiffness of vertical spring and initial gap settings of the magnet springs is derived for the QZS system. Based on the harmonic balance (HB) method, the force transmissibility is formulated and the jumping frequencies, effect of excitation force and damping ratio are discussed for characteristic analysis. An experimental prototype is developed and tested. The performance of the QZS system is verified through a series of experimental studies showing that the new model greatly outperforms standard linear isolation systems especially in low-frequency domain. The tuning techniques for adapting to the change of loading mass and adjusting the QZS property in practice are also addressed.

A dose–response study on the efficacy of tricyclic antidepressants on reducing morphine-withdrawal symptoms

BackgroundAcute detoxification may lead to withdrawal syndrome. The syndrome is sufficiently aversive in those who are morphine-dependents and thus it hinders abstinence. The opioids are most often used clinically to lighten this syndrome. Here, we evaluated the effects of tricyclic antidepressants (TCAs) in treating physical dependence to opioids upon acute detoxification in mice. Materials and methodsAdult NRL mice were rendered physically dependent on morphine by increasing daily doses of subcutaneous morphine for 3 days and precipitated withdrawal jumping by subcutaneous naloxone on Day 4. The mice were then assigned to receive intramuscular saline or one of the five TCAs 1 hour prior to creating naloxone-precipitated withdrawal. The withdrawal jumping frequency in 30 minutes was counted after naloxone-precipitated withdrawal. ResultsOur results (the newest findings) based on the equimolar dose (30 μmol/kg), showed that the severity of physical dependence on morphine could be attenuated with less intramuscular TCAs [percent maximal possible effect (MPE) < 50). Amoxapine, protriptyline, amitriptyline, clomipramine, and trimipramine produced a mean percent MPE (43, 18, 37, 45, and 36, respectively); amoxapine, protriptyline, amitriptyline, and clomipramine, also produced a dose-related effect on attenuating the severity of morphine dependence, but not trimipramine. A higher dose had a stronger effect. ConclusionAmoxapine, trimipramine, protriptyline, amitriptyline, and clomipramine could have a lightening effect on physical dependence on morphine.

Pharmacological modulation of geranylgeranyltransferase and farnesyltransferase attenuates opioid withdrawal in vivo and in vitro

Geranylgeranyltransferase and farnesyltransferase I, are noted to mediate a number of signal transduction cascades which are known to be involved in the causation of opioid withdrawal syndrome. GGTI-2133 and FTI-276 are selective modulators of geranylgeranyltransferase and farnesyltransferase subtype 1 respectively. Therefore, the present study investigated the effect of GGTI-2133 and FTI-276 on propagation of morphine dependence and resultant withdrawal signs in vivo, in sub-chronic morphine mouse model, and in vitro, in isolated rat ileum. Morphine was administered twice daily for 5 days following which a single day 6 injection of naloxone (8 mg/kg, i.p.) precipitated opioid withdrawal syndrome in mice. Withdrawal syndrome was quantitatively assessed in terms of withdrawal severity score and the frequency of jumping, rearing, fore paw licking & circling. Naloxone induced contraction in morphine withdrawn isolated rat ileum was employed as an in vitro model of opioid withdrawal syndrome. An isobolographic study design was employed to assess a potential synergistic activity between GGTI-2133 and FTI-276. GGTI-2133 and FTI-276 dose dependently attenuated naloxone induced morphine withdrawal syndrome both in vivo and in vitro. GGTI-2133 was also observed to exert a synergistic interaction with FTI-276. It is concluded that GGTI-2133 and FTI-276 attenuate the propagation of morphine dependence and reduce withdrawal signs possibly by a geranylgeranyl transferase; farnesyltransferase activation pathway linked mechanisms potentially in an interdependent manner.

Development of the Movements Impressions Emotions Model: Evaluation of Movements and Impressions Related to the Perception of Emotions in Dance

The purpose of this study is to specify the characteristics that contribute to the perception of emotions expressed through dance movements and to develop an emotional model to show the relationships between impressions and the characteristics of expressive body movements. Six dancers expressed three different emotions through dance: joy, sadness, and anger. Observers (N = 192) rated both their impressions (33 dimensions) and the dance movements (26 characteristics) of 18 dance performances. The results showed that the observers could accurately perceive the emotional meanings expressed in the dances. The impressions of Dynamics, Expansion, and Stability—and the evaluated movements of Frequency and Velocity of Upward Extension, Frequency and Velocity of Downward Movements, Turning or Jumping, and Body Closing—were extracted via factor analysis as determinants of observers’ impressions of emotional expressions in dance. Additionally, covariance structure analysis and discriminant function analysis indicated that the emotional expressions of the dances expressing joy, sadness, and anger are each associated with particular factors. Through these analyses, we developed the Movements Impressions Emotions Model for dance.

Horizontal dynamic forces generated by swaying and jumping

Modern assembly structures must be designed to withstand the dynamic forces generated by their human occupants; the characterization of these forces has become an important research topic. This paper focuses on the measurement and modelling of horizontal dynamic forces, which have previously received much less attention than vertical forces. Horizontal forces resulting from movements such as swaying and jumping were recorded using a tri-axial force plate and characterized using three properties: the impulse shape, the mean of the split impulse and the frequency spectrum. The fundamental force due to swaying occurred at the swaying frequency. However, the fundamental force due to jumping did not always occur at the jumping frequency, indicating that the current design procedure of assuming a horizontal load model similar to the vertical load model is not always appropriate. For some subjects the position of the centre of mass was simultaneously recorded using a motion capture system to establish a relationship between its velocity and the side-to-side force. Finally, a new, semi-empirical analytical model for representing horizontal forces in design calculations was developed. Results from the model show excellent agreement with measurements from the laboratory tests.

Study of the Size Dependence of Time-dependent Plastic Deformation of Gold Micro-pillars and Micro-spheres

ABSTRACTIn this study the length scale dependence of the operative mechanisms of time-dependent plastic deformation was studied using room temperature compression tests performed on Au micro-pillars and micro-spheres of 1.0 to 5.0 µm diameter. All the samples tested displayed deformation that had a component of random strain jumps. In the case of the Au micro-pillars, the frequency of the strain jumps showed a bilinear dependence upon pillar diameter with the frequency being larger, and more sensitive to diameter, when the pillar diameter was small (and τR was high). We suggest that this indicates a transition from deformation occurring by deformation on multiple slip planes to deformation occurring predominantly by single-plane dislocation slip when the pillar diameter is less than 2 µm.The strain jump frequency during the constant-load micro-pillar creep tests showed a linear dependence upon τR. Creep tests performed on the micro-spheres of 5.0 µm diameter displayed displacement jump frequency that was essentially independent of the applied load while the jump frequency increased with increasing load for the smaller 2.5 µm diameter micro-spheres. We suggest that this difference is related to the volume of the micro-sphere. When the volume is small, the component of the deformation that occurs by a stochastic dislocation glide process is increased and becomes strongly dependent upon the magnitude of the local shear stress.

Myosin Light Chain Kinase Binding and Transiting along and between Actin Filaments and Stress Fibers

The physical mechanism of Myosin Light Chain Kinase (MLCK) transiting between Smooth Muscle Myosin (SMM) molecules in a cell is incompletely understood. It is an interesting problem because the MLCK:SMM ratio is remarkably low (1:100) in smooth muscle cells yet smooth muscle activation still occurs on a sub-second time scale. We have shown that one MLCK can rapidly move between myosin molecules associated with a given actin filament by diffusing along that actin track and that MLCK can jump tracks. The diffusive rate along, and the jumping rate between, actin filaments could be significant determinants of the rate of smooth muscle activation. Here we use single particle tracking to understand the diffusive and jumping rates of the n-terminal (actin binding) domain of MLCK-QDots along and between actin filaments. We observe that the frequency of jumping increases as the distance between filaments decreases exponentially, consistent with a simple electrostatic model. Our experimentally measured jumping frequency and diffusion coefficient allow us to more accurately model the rate of smooth muscle activation as a function of MLCK:SMM ratios and the distance between actin filaments in smooth muscle cells.View Large Image | View Hi-Res Image | Download PowerPoint Slide

Nuclear quadrupole interactions of 111In/Cd solute atoms in a series of rare-earth palladium alloys

Nuclear quadrupole interactions were measured at 111In/Cd probe atoms in rare-earth palladium phases RPd3 having the L12 structure using the technique of perturbed angular correlation of gamma rays (PAC). Measurements were made for pairs of samples having compositions of the Pd-poorer and Pd-rich boundaries of the RPd3 phase fields, typically 75 and 78 at.% Pd. Two signals were detected in most phases, corresponding to probe atoms on cubic R- and non-cubic Pd-sublattices. Site preferences of parent In-probe atoms were characterized by site-fractions of probes on the R- and Pd-sublattices. For all Pd-rich samples, probes exclusively occupied the R-sublattice, consistent with a heuristic rule that solute atoms tend to occupy the sublattice of an element in which there is a deficiency. For Pd-poorer alloys with R= Tb, Er, Yb, Lu, Y and Sc, probes exclusively occupied the Pd-sublattice. For Pd-poorer alloys with R= Ce, Pr, Nd, Sm and Eu, probes occupied both sublattices, with site fractions varying as a function of temperature. In contrast, probes only occupied the R-sublattice in Pd-poorer LaPd3. Jump frequencies on the Pd-sublattice of daughter Cd-probes were determined from nuclear relaxation caused by fluctuating electric field gradients. Activation enthalpies for diffusional jumps were determined from temperature dependences and found to increase linearly as the lattice parameter decreases along the series Pr, Nd, Eu and Sm. Jump frequencies are believed to have been even higher in CePd3 than in PrPd3, but were too low to be detectable in Tb, Er, Yb, Lu, Y and Sc palladides. A correlation between site preferences and jump frequencies is noted and discussed. This paper provides a complete account of measurements of jump frequencies of Cd-probe atoms and comparisons with similar measurements made on other series of L12 phases.