988 research outputs found

    Phase reduction of stochastic limit cycle oscillators

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    We point out that the phase reduction of stochastic limit cycle oscillators has been done incorrectly in the literature. We present a correct phase reduction method for oscillators driven by weak external white Gaussian noises. Numerical evidence demonstrates that the present phase equation properly approximates the dynamics of the original full oscillator system.Comment: 4 pages, 2 figure

    Changes in Shear Force and Inward Pressure inside Plug-fit Sockets Due to Flexion and Extension of the Elbow Joint

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    This study measured shear force and pressure of prosthesis sockets and compared sockets made from conventional hard acrylic resin with soft material. In addition, we also examined how the acrylic resin of the socket influences the decision to put on an elbow system prosthesis. We found that the soft socket extended the range of motion of the elbow joint and permitted movement of the soft tissue to a greater extent than the hard socket. Furthermore, the movable range of the elbow joint widened as the shape of the socket itself changed

    Influence of Active Fingertip Contact with a Stable Surface on Postural Sway and Electromyographic Activities of the Lower Extremity Muscles Immediately after Descending a Step

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    Recent studies have shown that active contact cues from a fingertip provide information that leads to reduced postural sway during static standing. Although the falling risk increases immediately after descending a step, little is known about the influence of active fingertip contact with a stable surface. The purpose of this study was to investigate the influence of fingertip contact on the sway and the EMG (Electromyographic) activities of lower extremity muscles immediately after descending a step. Nine healthy male volunteers participated in this study. Sway was measured by the center of pressure (COP) and compared under three conditions: (1) standing without touching, (2) standing with the right index fingertip lightly touching (<1N), and (3) standing forcefully touching (5~10N). EMG activities were measured associated with sway and compared. More areas of COP were observed while standing without touching than while standing with light or forceful touching, but there was no significant difference between the two touching conditions. No significant differences in the length of COP and the EMG activities were observed among the three conditions. The results suggested that the fingertip touch contact with a stable surface decreased sway immediately after descending a step by finely controlling the lower extremity muscles

    CO2 efflux from leaf litter focused on spatial and temporal heterogeneity of moisture

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    Leaf litter respiration (R [LL]) was directly measured in situ to evaluate relationships with the water content in leaf litter (WC), which is distributed heterogeneously under natural conditions. To do so, we developed a small, closed static chamber system using an infrared gas analyzer, which can measure instantaneous R [LL]. This study focuses on the measurement of CO2 effluxes from leaf litter using the chamber system in the field and examines the relationship between R [LL] and WC among seven broadleaf species in a temperate forest. The measurements focused on the position of leaves within the litter layer, finding that both R [LL] and WC were significantly higher in the lower layer. The value of R [LL] increased with increasing WC, and the response of R [LL] to WC was similar among all seven species. Moreover, the temporal variation in WC differed among three species and was associated with leaf litter thickness. The observed heterogeneity in WC induced by the physical environment (e.g., position and thickness of leaf litter) affects the variation in WC and, therefore, both R [LL] and the decomposition rates of organic matter in the litter layer

    Fast-Ion-Diagnostics for CHS Experiment

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    Fast-ion-diagnostics have played an important role in investigating issues related to fast ion orbits and fast-ion-driven MHD instabilities in CHS experiments. The fast-ion diagnostics employed in CHS are reviewed and experimentally obtained knowledge is summarized

    Alterations of circulating endothelial cell and endothelial progenitor cell counts around the ovulation.

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    Context:Circulating endothelial cells (CECs) and progenitor cells (CEPs) have been intensively studied as a promising tool for treating ischemic diseases and monitoring cancer treatments, but how the menstrual cycle affects the variation in their counts remains unclear. Objective:The aims of the study were to determine the influence of the menstrual cycle on the number of CECs and CEPs and to investigate the association of their counts with circulating hormones and angiogenesis-associated factors. Design:CEP and CEC counts by flow cytometry and the CellSearch system and circulating factor levels were measured eight times during the menstrual cycle in 18 volunteers. The menstrual cycle was divided into six phases based on hormone concentrations. Results:CEP counts peaked in the periovulatory and middle luteal phases with a drop in the early luteal phase. CEC counts showed no significant variation. There were significant correlations between the CEP counts and the serum concentrations of estradiol (E2), LH, and granulocyte colony-stimulating factor (G-CSF) (P < 0.0001, P < 0.0001, and P = 0.01, respectively). The difference in CEP counts between two adjacent phases was significantly correlated with that in E2, LH, G-CSF, and serum vascular endothelial growth factor (P < 0.0001, P < 0.0001, P = 0.02, and P = 0.006, respectively). Conclusion:CEP counts peaked in the periovulatory and middle luteal phases, with a drop in the early luteal phase, and were correlated with serum E2, LH, and G-CSF concentrations. Consideration of the variation in CEP counts would be important for the clinical application of CEPs
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