Curvilinear trajectory of track machines

2021 ◽  
Author(s):  
A. G. Amosov
Keyword(s):  
Curvilinear Trajectory

scholarly journals The method of taking into the drift in determining the trajectory of the curvinal movement of the tractor

1970 ◽  
pp. 25-29
Author(s):  
M Dovzhyk ◽  
O Solarov ◽  
О Kalnahus ◽  
О Tatsenko
Keyword(s):  
Automatic Control ◽  
Velocity Vector ◽  
Complete Loss ◽  
Neutral Position ◽  
Main Task ◽  
Positive Direction ◽  
Curvilinear Motion ◽  
Curvilinear Trajectory ◽  
Wheeled Vehicles ◽  
Angle Of Rotation

This article discusses how to construct a curvilinear trajectory for a four-wheeled machine with front steered wheels. Important effects on curvilinear motion are phenomena such as slipping and skidding, which in turn influence the construction of the trajectory. Knowing how the movement of the wheels affects the movement, we can accurately construct the trajectory, namely the entrance and exit of the turn. The main task we wanted to solve was to find the easiest ways to construct a curved trajectory of the machine. It is known that the angle between the velocity vector of the wheel and the positive direction of the axis of the tractor corresponding to the neutral position of the wheels is called the angle of withdrawal. It is also known that the deflection angles arising from the curvilinear movement of wheeled vehicles due to tire deformation distort the trajectory of motion and have a significant effect on the controllability of the machine up to its complete loss. Therefore, it is no coincidence that a large number of works is devoted to investigating the causes of the emergence of angles and their dependence on various factors. Tire theory is taught throughout the course of this subject, but nevertheless it cannot be assumed that the phenomenon has been sufficiently studied so that it can be confidently used in determining trajectories, which is especially important in the development of methods of automatic control of the vehicle . The angle of rotation of the wheels depends on many factors, and often these dependencies are quite complex.

scholarly journals Age Influences Loss Aversion Through Effects on Posterior Cingulate Cortical Thickness

2021 ◽  
Vol 15 ◽  
Author(s):  
Zoe R. Guttman ◽  
Dara G. Ghahremani ◽  
Jean-Baptiste Pochon ◽  
Andy C. Dean ◽  
Edythe D. London
Keyword(s):  
Loss Aversion ◽  
Cingulate Cortex ◽  
Brain Regions ◽  
Posterior Cingulate Cortex ◽  
Structural Magnetic Resonance Imaging ◽  
Posterior Cingulate ◽  
Age Related ◽  
Curvilinear Trajectory ◽  
The Relationship ◽  
Healthy Participants

Decision-making strategies shift during normal aging and can profoundly affect wellbeing. Although overweighing losses compared to gains, termed “loss aversion,” plays an important role in choice selection, the age trajectory of this effect and how it may be influenced by associated changes in brain structure remain unclear. We therefore investigated the relationship between age and loss aversion, and tested for its mediation by cortical thinning in brain regions that are susceptible to age-related declines and are implicated in loss aversion — the insular, orbitofrontal, and anterior and posterior cingulate cortices. Healthy participants (n = 106, 17–54 years) performed the Loss Aversion Task. A subgroup (n = 78) provided structural magnetic resonance imaging scans. Loss aversion followed a curvilinear trajectory, declining in young adulthood and increasing in middle-age, and thinning of the posterior cingulate cortex mediated this trajectory. The findings suggest that beyond a threshold in middle adulthood, atrophy of the posterior cingulate cortex influences loss aversion.

94 ADDITION OF REDUCED GLUTATHIONE TO THAWING MEDIUM IMPROVED THE SPERM MOTILITY AND REDUCED ROS GENERATION IN FROZEN OVINE AND CAPRINE SPERMATOZOA

2006 ◽  
Vol 18 (2) ◽  
pp. 155 ◽  
Author(s):  
J. C. Gardón ◽  
J. A. Rodriquez ◽  
J. Gadea
Keyword(s):  
Sperm Motility ◽  
Reduced Glutathione ◽  
Ovis Aries ◽  
Capra Hircus ◽  
Ros Generation ◽  
Computer Assisted ◽  
Sperm Analysis ◽  
Spermatozoa Motility ◽  
Curvilinear Trajectory ◽  
Motility Parameters

The processes of cooling and freezing/thawing produce physical and chemical stress on the sperm membrane, and this stress is associated with oxidative stress and reactive oxygen species (ROS) generation that further reduce sperm viability and fertilizing ability. It is known that the process of freezing is associated with a significant reduction of the intracellular reduced glutathione (GSH) content. The aim of these experiments was to investigate the effects of addition of GSH to thawing extenders on motility parameters and ROS generation in frozen-thawed ovine and caprine spermatozoa. Frozen spermatozoa from eight rams (Ovis aries) and eight bucks (Capra hircus) (generously provided by Ovigen, Zamora, Spain) were thawed in a water bath at 37�C for 30 s and resuspended in sperm-TALP medium (Parrish et al. 1986 Theriogenology 25, 591-600) without (control) and with addition of 1 mM or 5 mM GSH. After 30 min of incubation at 37�C, sperm motility was evaluated using a computer-assisted sperm analysis (CASA) system (SCA, Microptic, Barcelona, Spain). The recorded parameters of motility were: % total, % progressive, curvilinear velocity, straight-line velocity, average path velocity, linearity of the curvilinear trajectory, straightness, amplitude of lateral head displacement, wobble of the curvilinear trajectory and beat cross frequency. Another set of sperm samples was incubated in the presence of (0.7 �M) 22,72-dichlorodihydrofluorescein diacetate (Gadea et al. 2005 J. Androl. 26, 396-404) to estimate production of ROS by flow cytometry. Data were analyzed by two-way ANOVA, considering the specific sperm treatment (GSH addition) and the males as the main variables. In ram frozen spermatozoa, all of the motility parameters were significantly improved when the medium was supplemented with GSH (P < 0.01) with even better results when 5 mM GSH was used. As an example, progresive motility increased from 31.16% (control) to 39.17 and 43.97%, respectively, for 1 and 5 mM GSH. Despite of the male effect detected (P < 0.01), all eight rams studied presented a similar pattern (interaction P > 0.05). The generation of ROS was significantly reduced when GSH was added (6.23a for control vs. 5.32b and 3.85c for 1 and 5 mM, respectively; P < 0.01). In buck frozen spermatozoa, % motility and progressive motility were significantly higher in GSH groups than in the control (P < 0.01), with no differences between 1 and 5 mM GSH. However, for the other motility parameters, the differences were not significant, which probably could be related to differences in the pattern shown by different animals (interaction of buck by treatment P < 0.05). ROS generation was significantly reduced when GSH was added (7.50a for control vs. 4.32b and 2.70b for 1 and 5 mM, respectively; P < 0.01). The addition of GSH to the thawing medium had a positive influence on the parameters studied in both species, increasing the motility patterns and reducing the ROS generation. In conclusion, we can assume that the addition of reduced glutathione to the thawing medium exerts a protective effect on spermatozoa functionality. This work was supported by AGL-2003-03144.

329 COMPARING CHANGES IN MOTION PARAMETERS IN EPIDIDYMAL AND EJACULATED BOAR SPERMATOZOA UNDER THREE DIFFERENT TREATMENTS

2007 ◽  
Vol 19 (1) ◽  
pp. 280
Author(s):  
M. Sansegundo ◽  
J. C. Gardon ◽  
F. Garcia-Vazquez ◽  
J. Gadea ◽  
C. Matas
Keyword(s):  
Seminal Plasma ◽  
Objective Assessment ◽  
Mammalian Species ◽  
Computer Assisted ◽  
Sperm Analysis ◽  
Motion Parameters ◽  
Computer Assisted Sperm Analysis ◽  
Boar Spermatozoa ◽  
Curvilinear Trajectory

The motion ability of mammalian spermatozoa is acquired during their epididymal transit but observed only upon dilution with seminal plasma (SP) at the time of ejaculation (Yanahimachi 1994 in The Physiology of Reproduction, New York: Raven Press). The bicarbonate present in seminal plasma activates multiple sperm functions, some of which are essential for the initiation of motility. Sperm hyperactivity has been observed in vitro in various mammalian species, especially if capacitation of spermatozoa was induced with Ca2+ and bicarbonate media, such as TALP (Harrison et al. 1996 Mol. Reprod. Dev. 45, 378–391). Computer-assisted sperm analysis (CASA) is a tool for the objective assessment of sperm motility. The aim of this study was to determine if there are differences in motility parameters of ejaculated (EJ) and epididymal (EP) boar spermatozoa under different treatments. Ejaculated and epididymal sperm cells from 10 different boars in each group were used. The sperm treatments were: washed in Dulbecco&apos;s PBS supplemented with 0.1&percnt; BSA (PBS-BSA), washed on a Percoll gradient (PG), and unwashed (UW: Control); the sperm samples were incubated in TALP medium at 38.5&deg;C and 5&percnt; CO2 during the analysis. Motion parameters were determined using a computer-assisted sperm analysis (CASA) system. A 7-&micro;L drop of the sample was placed on a warmed (37&deg;C) slide. At least 4 fields per sample were evaluated, with a minimum of 100 spermatozoa counted per sub-sample. The CASA-derived motility characteristics studied were motility (MOT, &percnt;), progressive motility (PM, &percnt;), curvilinear velocity (VCL, &micro;m s&minus;1), straight-line velocity (VSL, &micro;m s&minus;1), average path velocity (VAP, &micro;m s&minus;1), linearity of the curvilinear trajectory (LIN, ratio of VSL/VCL, &percnt;), straightness (STR, ratio of VSL/VAP, &percnt;), amplitude of lateral head displacement (ALH, &micro;m), wobble of the curvilinear trajectory (WOB, ratio of VAP/VCL, &percnt;), and beat cross-frequency (BCF, Hz). Data were analyzed by ANOVA. If we evaluated all of the data together (EJ vs. EP), EP sperm after treatment showed a higher motility (PM: 38.20&percnt;; MOT: 74.23&percnt;) than EJ sperm (PM: 29.27&percnt;; MOT: 63.24&percnt;), and all of the motion parameters related to velocities and ALH were higher in EP (VCL: 86.02; VSL: 41; VAP: 57.94; ALH: 3.21) than in EJ (VCL: 69.70; VSL: 34.67; VAP: 48.16; ALH: 2.54). No differences were found for LIN, STR, WOB, and BCF. The treatments significantly affected the VCL and ALH, with lower values for the PG treatment. When VCL was lower and the VSL and VAP were similar, consequently the LIN and WOB were significantly higher for the PG group. STR also was higher for the PG group. In conclusion, when both groups of sperm were incubated in TALP medium, the EJ sperm showed a decrease in the majority of motion parameters when compared with EP sperm. This work was supported by MEC (AGL2006-03495/GAN) and Fundaci&oacute;n S&eacute;neca (03018/PI/05).

scholarly journals The adaptation to standing long jump distance in parkour is performed by the modulation of specific variables prior and during take-off

2017 ◽  
pp. 27-37
Author(s):  
Sidney Grosprêtre ◽  
Pierre Ufland ◽  
Daniel Jecker
Keyword(s):  
Center Of Pressure ◽  
Vertical Jump ◽  
Standing Long Jump ◽  
Jump Distance ◽  
Long Jump ◽  
Reaction Forces ◽  
Similar Distance ◽  
Force Time ◽  
Jump Trajectory ◽  
Curvilinear Trajectory

The present study aimed at investigating different variables that can be manipulated prior to and during take-off, to execute a specific standing long jump (SLJ) distance, according to jump expertise in parkour practitioners (= traceurs). Fourteen healthy young traceurs were included and separated into two groups: beginners (BEG) and experts (EXP). Firstly, classical vertical jump battery was used to characterize participants arm use and leg efficiency. Secondly, standing long jump (SLJ) performances were analyzed at four distances: 70, 80, 90, and 100% of each participant’s maximal SLJ distance. The force-time curves of the ground reaction forces (GRF) and the center of pressure (CoP) trajectory were measured with a force platform during the jump impulses. Take-off speed, angle and jump trajectory were estimated. For all of the participants, take-off speed and angle, power output, and vertical GRF during jump preparation (counter movement) varied with distance. The EXP group exhibited greater backward CoP excursion, greater arm participation, greater take-off velocity and a greater modulation of take-off angle than BEG group. When comparing jumps of similar distance, EXP exhibited a more curvilinear trajectory with a higher peak than BEG. To conclude, different motor strategies can be adopted based on the jump distance, and these strategies can evolve as parkour experience increases.

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