83 research outputs found
Stochastic matrix for
We show that the quantum matrix for symmetric tensor representations of
satisfies the sum rule required for its stochastic
interpretation under a suitable gauge. Its matrix elements at a special point
of the spectral parameter are found to factorize into the form that naturally
extends Povolotsky's local transition rate in the -Hahn process for .
Based on these results we formulate new discrete and continuous time integrable
Markov processes on a one-dimensional chain in terms of species of
particles obeying asymmetric stochastic dynamics. Bethe ansatz eigenvalues of
the Markov matrices are also given.Comment: 21 pages. Remark 9 added, Typos in Appendix A fixe
Insights into motor learning from a viewpoint of transcranial magnetic stimulation
Several protocols of non-invasive transcranial magnetic stimulation have been developed in the past decades. Single-and paired-pulse transcranial magnetic stimulation are painless, and noninvasive tools to evaluate cortical and corticospinal excitability in cerebral cortex compared with transcranial electric stimulation. Motor evoked potential induced by paired-pulse transcranial magnetic stimulation can particularly assess changes of the cortical excitability after motor learning, such as motor skill and motor practice in sports and functional recovery in rehabilitation. However, the effect of electric current in transcranial magnetic stimulation on pyramidal neuron and interneuron in gray and white matters is not actually understood well yet in the field of sports and rehabilitation sciences. Here, we show the important basic knowledge of neurophysiology and transcranial magnetic stimulation and introduce some studies of cortical plasticity and motor learning by using transcranial magnetic stimulation
Comparison of stochastic stability boundaries for parametrically forced systems with application to ship rolling motion
Numerous accidents caused by parametric rolling have been reported on
container ships and pure car carriers (PCCs). A number of theoretical studies
have been performed to estimate the occurrence condition of parametric rolling
in both regular and irregular seas. Some studies in random wave conditions have
been the approximate extension of the occurrence conditions for regular waves
(e.g. Maki et al). Furthermore, several researches have been based on the
stochastic process in ocean engineering (Roberts and Dostal). This study
tackled the parametric rolling in irregular seas from the stability of the
system's origin. It provided a novel theoretical explanation of the instability
mechanism for two cases: white noise parametric excitation and colored noise
parametric excitation. The authors then confirmed the usefulness of the
previously provided formulae by Roberts and Dostal through numerical examples.Comment: 10 pages, 4 figure
Approximate probability density function for nonlinear surging in irregular following seas
The broaching that follows the surf-riding is a dangerous phenomenon that can
lead to the capsizing of a vessel due to its violent yaw motion. Most of the
previous studies on surf-riding phenomena in irregular waves have been
conducted by replacing irregular waves with regular waves. In contrast, this
study provides suggestions on how to directly calculate nonlinear surge motion
in irregular seas. In this study, the statistical aspects of the surf-riding
phenomenon are first presented. Then, under several approximations, we show how
to calculate the probability density function theoretically. Although the
results obtained are based on strong approximations, it is found that the
nonlinear surge oscillations in irregular following seas can be explained from
a qualitative point of view
Comparison of stochastic stability boundaries for parametrically forced systems with application to ship rolling motion
The version of record of this article, first published in Journal of Marine Science and Technology (Japan), is available online at Publisherâs website: https://doi.org/10.1007/s00773-024-00999-0.Numerous accidents caused by parametric rolling have been reported on container ships and pure car carriers (PCCs). Considering this dangerous phenomenon, the parametric rolling in irregular seas is examined in this paper based on the stability of the systems origin, which corresponds to the upright condition of the vessel. It provides a novel theoretical explanation of the instability mechanism for two cases: white-noise parametric excitation and colored-noise parametric excitation. Moreover, the authors confirm the usefulness of the previously provided formulae by Roberts and Dostal by means of numerical examples
Effect of endurance training on excessive CO2 expiration due to lactate production in exercise
We attempted to determine the change in total excess volume of CO2 Output (CO2 excess) due to bicarbonate buffering of lactic acid produced in exercise due to endurance training for approximately 2 months and to assess the relationship between the changes of CO2 excess and distance-running performance. Six male endurance runners, aged 19â22 years, were subjects. Maximal oxygen uptake (VO2max), oxygen uptake (VO2) at anaerobic threshold (AT), CO2 excess and blood lactate concentration were measured during incremental exercise on a cycle ergometer and 12-min exhausting running performance (12-min ERP) was also measured on the track before and after endurance training. The absolute magnitudes in the improvement due to training for C02 excess per unit of body mass per unit of blood lactate accumulation (Alaâ) in exercise (CO2 excess·massâ1·Îlaâ), 12-min ERP, VO2 at AT (AT-VO2) and VO2max on average were 0.8 ml·kgâ1·lâ1·mmolâ1, 97.8m, 4.4 ml·kgâ1· minâ1 and 7.3 ml·kgâ1·minâ1, respectively. The percentage change in CO2 excess·massâ1·Îlaâ (15.7%) was almost same as those of VO2max (13.7%) and AT-VO2 (13.2%). It was found to be a high correlation between the absolute amount of change in CO2 excess·massâ1·Îlaâ and the absolute amount of change in AT-VO2 (r=0.94, P<0.01). Furthermore, the absolute amount of change in C02 excess·massâ1·Îlaâ, as well as that in AT-VO2 (r=0.92, P<0.01), was significantly related to the absolute amount of change in 12-min ERP (r=0.81, P<0.05). It was concluded that a large CO2excess·massâ1·Îlaâ1 of endurance runners could be an important factor for success in performance related to comparatively intense endurance exercise such as 3000â4000 m races
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