635 research outputs found
Reproducibility of a noisy limit-cycle oscillator induced by a fluctuating input
Reproducibility of a noisy limit-cycle oscillator driven by a random
piecewise constant signal is analyzed. By reducing the model to random phase
maps, it is shown that the reproducibility of the limit cycle generally
improves when the phase maps are monotonically increasing.Comment: 4 pages, 3 figures, Prog. Theoret. Phys. Suppl. 200
Long-range nematic order and anomalous fluctuations in suspensions of swimming filamentous bacteria
We study the collective dynamics of elongated swimmers in a very thin fluid
layer by devising long, filamentous, non-tumbling bacteria. The strong
confinement induces weak nematic alignment upon collision, which, for large
enough density of cells, gives rise to global nematic order. This homogeneous
but fluctuating phase, observed on the largest experimentally-accessible scale
of millimeters, exhibits the properties predicted by standard models for
flocking such as the Vicsek-style model of polar particles with nematic
alignment: true long-range nematic order and non-trivial giant number
fluctuations.Comment: 6 pages, 4 figures. Supplemental Material: 6 pages, 3 figure
Galaxy orbits and the intracluster gas temperature in clusters
In this paper we examine how well galaxies and intra-cluster gas trace the
gravitational potential of clusters. Utilizing mass profiles derived from
gravitational lensing and X-ray observations, coupled with measured galaxy
velocities, we solve for the velocity anisotropy parameter using the
anisotropic Jeans equation. This is done for five clusters, three at low
redshift: A2199, A496 and A576 and two at high redshifts: A2390 and MS1358.
With X-ray temperature profiles obtained from Chandra and ASCA/ROSAT data, we
estimate the ratio of energy in the galaxies compared to the X-ray gas. We find
that none of these clusters is strictly in hydro-static equilibrium. We compare
the properties of our sample with clusters that form in high-resolution
cosmological N-body simulations that include baryonic physics. Simulations and
data show considerable scatter both these profiles. We demonstrate the future
feasibility and potential for directly comparing the orbital structure of
clusters inferred from multi-wavelength observations with high resolution
simulated clusters.Comment: 9 pages, 6 figures, accepted for publication in MNRA
Mode Selection in the Spontaneous Motion of an Alcohol Droplet
An alcohol (pentanol) droplet exhibits spontaneous agitation on an aqueous
solution, driven by a solutal Marangoni effect. We found that the droplet's
mode of motion is controlled by its volume. A droplet with a volume of less
than shows irregular translational motion, whereas
intermediate-sized droplets of show vectorial motion. When
the volume is above , the droplet splits into smaller drops.
These experimental results regarding mode selection are interpreted in terms of
the wave number selection depending on the droplet volume.Comment: 4 pages, 5 figure
Change of lip function by lip-closing training using visual feedback.
松本歯科大学大学院独立研究科博士(歯学)学位申請論文 ; 大学院歯学独立研究科 顎口腔機能制御学講座(主指導教員:増田 裕次 教授
Regular self-motion of a liquid droplet powered by the chemical marangoni effect
We describe here our recent work on spontaneous regular motion of liquid droplet powered by the chemical Marangoni effect under spatially symmetric conditions. It is shown that a spontaneously crawling oil droplet on a glass substrate with a nonequilibrium chemical condition of cationic surfactant exhibits regular rhythmic motion in a quasi-one-dimensional vessel, whereas irregular motion is induced in a two-dimensionally isotropic environment. Such behavior of a droplet demonstrates that spontaneous regular motion can be generated under fluctuating conditions by imposing an appropriate geometry. As another system, we introduce alcohol droplet moving spontaneously on water surface. The droplet spontaneously forms a specific morphology depending on its volume, causing specific mode of translational motion. An alcohol droplet with a smaller volume floating on water surface moves irregularly. On the other hand, a droplet with a larger volume undergoes vectorial motion accompanied by deformation into an asymmetric shape. This result suggests a scenario on the emergence of regular motion coupled with geometrical pattern formation under far-from-equilibrium conditions
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