1,476 research outputs found
Mixed mode pattern in Doublefoot mutant mouse limb - Turing reaction-diffusion model on a growing domain during limb development
It has been suggested that the Turing reaction–diffusion model on a growing domain is applicable during limb development, but experimental evidence for this hypothesis has been lacking. In the present study, we found that in Doublefoot mutant mice, which have supernumerary digits due to overexpansion of the limb bud, thin digits exist in the proximal part of the hand or foot, which sometimes become normal abruptly at the distal part. We found that exactly the same behaviour can be reproduced by numerical simulation of the simplest possible Turing reaction–diffusion model on a growing domain. We analytically showed that this pattern is related to the saturation of activator kinetics in the model. Furthermore, we showed that a number of experimentally observed phenomena in this system can be explained within the context of a Turing reaction–diffusion model. Finally, we make some experimentally testable predictions
Improvement of solar cycle prediction: Plateau of solar axial dipole moment
Aims. We report the small temporal variation of the axial dipole moment near
the solar minimum and its application to the solar cycle prediction by the
surface flux transport (SFT) model. Methods. We measure the axial dipole moment
using the photospheric synoptic magnetogram observed by the Wilcox Solar
Observatory (WSO), the ESA/NASA Solar and Heliospheric Observatory Michelson
Doppler Imager (MDI), and the NASA Solar Dynamics Observatory Helioseismic and
Magnetic Imager (HMI). We also use the surface flux transport model for the
interpretation and prediction of the observed axial dipole moment. Results. We
find that the observed axial dipole moment becomes approximately constant
during the period of several years before each cycle minimum, which we call the
axial dipole moment plateau. The cross-equatorial magnetic flux transport is
found to be small during the period, although the significant number of
sunspots are still emerging. The results indicates that the newly emerged
magnetic flux does not contributes to the build up of the axial dipole moment
near the end of each cycle. This is confirmed by showing that the time
variation of the observed axial dipole moment agrees well with that predicted
by the SFT model without introducing new emergence of magnetic flux. These
results allows us to predict the axial dipole moment in Cycle 24/25 minimum
using the SFT model without introducing new flux emergence. The predicted axial
dipole moment of Cycle 24/25 minimum is 60--80 percent of Cycle 23/24 minimum,
which suggests the amplitude of Cycle 25 even weaker than the current Cycle 24.
Conclusions. The plateau of the solar axial dipole moment is an important
feature for the longer prediction of the solar cycle based on the SFT model.Comment: 5 pages, 3 figures, accepted for publication in A&A Lette
Three Dimensional Structure and Energy Balance of a Coronal Mass Ejection
The Ultraviolet Coronagraph Spectrometer (UVCS) observed Doppler shifted
material of a partial Halo Coronal Mass Ejection (CME) on December 13 2001. The
observed ratio of [O V]/O V] is a reliable density diagnostic important for
assessing the state of the plasma. Earlier UVCS observations of CMEs found
evidence that the ejected plasma is heated long after the eruption. We have
investigated the heating rates, which represent a significant fraction of the
CME energy budget. The parameterized heating and radiative and adiabatic
cooling have been used to evaluate the temperature evolution of the CME
material with a time dependent ionization state model. The functional form of a
flux rope model for interplanetary magnetic clouds was also used to
parameterize the heating. We find that continuous heating is required to match
the UVCS observations. To match the O VI-bright knots, a higher heating rate is
required such that the heating energy is greater than the kinetic energy. The
temperatures for the knots bright in Ly and C III emission indicate
that smaller heating rates are required for those regions. In the context of
the flux rope model, about 75% of the magnetic energy must go into heat in
order to match the O VI observations. We derive tighter constraints on the
heating than earlier analyses, and we show that thermal conduction with the
Spitzer conductivity is not sufficient to account for the heating at large
heights.Comment: 40 pages, 16 figures, accepted for publication in ApJ For associated
mpeg file, please see https://www.cora.nwra.com/~jylee/mpg/f5.mp
A Research of Basic Energy Reduction Approach Using PV Power Smoothing EV Storage System and LED Simple Circuit for Create Green Innovation
In general, Light Emitting Diode (LED) is low power consumption, and Photovoltaic (PV) generation of Renewable Energy is effective as energy creation. However, LED applications have a problem of LED Circuit Radiation Noise and PV generation applications have a problem of the Output Power fluctuation in the weather. This paper will be proposed as an especial approach of the energy reduction to contribute to the realization of the low carbon society in the world. In this research, without using Common Mode Choke (CMC) Noise Cut filter, the Radiation Noise reduction result in World Standard Guideline by the selection of a simple circuit of the most effective LED lighting of various power reduction methods have been confirmed by the examinations. Additionally, in order to investigate the lighting specification, the simple Lighting evaluation equipment has been developed. As an energy fluctuation reduction research, the new control system of the PV fluctuation electric power using EV battery charge-discharge electric power that is able to be easily connected with a Power Conditioning System (PCS) input is proposed. A simulation result using the actual PV generator output data is provided to confirm the effectiveness of Simple Moving Average (SMA) method. Moreover, the outline of a new large area monitoring control GIS system for the implementation of the PV generator power prognostication without the weather estimation is introduced.九工大・マレーシアプトラ大学国際合同シンポジウム: International Symposium on Applied Engineering and Sciences (SAES), September 30- October 1, 2013, Universiti Putra Malaysia, Malaysi
Observations of Post-flare Plasma Dynamics during an M1.0 Flare in AR11093 by SDO/AIA
We observe the motion of cool and hot plasma in a multi-stranded post flare
loop system that evolved in the decay phase of a two ribbon M1.0 class flare in
AR 11093 on 7 August 2010 using SDO/AIA 304 \AA\ and 171 \AA\ filters. The
moving intensity feature and its reflected counterpart are observed in the loop
system at multi-temperature. The observed hot counterpart of the plasma that
probably envelopes the cool confined plasma, moves comparatively faster
(34 km s) to the later (29 km s) in form of the spreaded
intensity feature. The propagating plasma and intensity reflect from the region
of another footpoint of the loop. The subsonic speed of the moving plasma and
associated intensity feature may be most likely evolved in the post flare loop
system through impulsive flare heating processes. Complementing our
observations of moving multi-temperature intensity features in the post flare
loop system and its reflection, we also attempt to solve two-dimensional ideal
magnetohydrodynamic equations numerically using the VAL-IIIC atmosphere as an
initial condition to simulate the observed plasma dynamics. We consider a
localized thermal pulse impulsively generated near one footpoint of the loop
system during the flare processes, which is launched along the magnetic field
lines at the solar chromosphere. The pulse steepens into a slow shock at higher
altitudes while moving along this loop system, which triggers plasma
perturbations that closely exhibit the observed plasma dynamics.Comment: 23 Pages, 4 Figures, The Astrophysical Journal (ApJ
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