10,488 research outputs found
Diversity, Stability, Recursivity, and Rule Generation in Biological System: Intra-inter Dynamics Approach
Basic problems for the construction of a scenario for the Life are discussed.
To study the problems in terms of dynamical systems theory, a scheme of
intra-inter dynamics is presented. It consists of internal dynamics of a unit,
interaction among the units, and the dynamics to change the dynamics itself,
for example by replication (and death) of units according to their internal
states. Applying the dynamics to cell differentiation, isologous
diversification theory is proposed. According to it, orbital instability leads
to diversified cell behaviors first. At the next stage, several cell types are
formed, first triggered by clustering of oscillations, and then as attracting
states of internal dynamics stabilized by the cell-to-cell interaction. At the
third stage, the differentiation is determined as a recursive state by cell
division. At the last stage, hierarchical differentiation proceeds, with the
emergence of stochastic rule for the differentiation to sub-groups, where
regulation of the probability for the differentiation provides the diversity
and stability of cell society. Relevance of the theory to cell biology is
discussed.Comment: 19 pages, Int.J. Mod. Phes. B (in press
Proton-neutron alignment in the yrast states of Ge and Ge
The Ge and Ge nuclei are studied by means of the shell model
with the extended Hamiltonian, which succeeds in reproducing
experimentally observed energy levels, moments of inertia and other properties.
The investigation using the reliable wave-functions predicts T=0, J=9
one-proton-one-neutron () alignment in the orbit, at high spins
(, and ) in these even-even nuclei. It
is shown that a series of the even- positive-parity yrast states (observed
up to for Ge) consists of the ground-state band and successive
three bands with different types of particle alignments (two-neutron, ,
two-proton-two-neutron) in the orbit.Comment: 4 pages, 5 figures, to be published in Pyhs. Rev.
Shape transition and oblate-prolate coexistence in N=Z fpg-shell nuclei
Nuclear shape transition and oblate-prolate coexistence in nuclei are
investigated within the configuration space (, ,
, and ). We perform shell model calculations for Zn,
Ge, and Se and constrained Hartree-Fock (CHF) calculations for
Zn, Ge, Se, and Kr, employing an effective pairing
plus quadrupole residual interaction with monopole interactions. The shell
model calculations reproduce well the experimental energy levels of these
nuclei. From the analysis of potential energy surface in the CHF calculations,
we found shape transition from prolate to oblate deformation in these
nuclei and oblate-prolate coexistence at Se. The ground state of
Se has oblate shape, while the shape of Zn and Ge are
prolate. It is shown that the isovector matrix elements between and
orbits cause the oblate deformation for Se, and four-particle
four-hole () excitations are important for the oblate configuration.Comment: 6 pages, 5 figures, accepted for publication in Phys. Rev.
Cosmological Family Asymmetry and CP violation
We discuss how the cosmological baryon asymmetry can be achieved by the
lepton family asymmetries of heavy Majorana neutrino decays and they are
related to CP violation in neutrino oscillation, in the minimal seesaw model
with two heavy Majorana neutrinos. We derive the most general formula for CP
violation in neutrino oscillation in terms of the heavy Majorana masses and
Yukawa mass term. It is shown that the formula is very useful to classify
several models in which , and leptogenesis can be separately
realized and to see how they are connected with low energy CP violaton. To make
the models predictive, we take texture with two zeros in the Dirac neutrino
Yukawa matrix. In particular, we find some interesting cases in which CP
violation in neutrino oscillation can happen while lepton family asymmetries do
not exist at all. On the contrary, we can find , and
leptogenesis scenarios in which the cosmological CP violation and low
energy CP violation measurable via neutrino oscillations are very closely
related to each other. By determining the allowed ranges of the parameters in
the models, we predict the sizes of CP violation in neutrino oscillation and
. Finally, the leptonic unitarity triangles are reconstructed.Comment: 22 pages, 9 figures A figure caption correcte
Projection neurons in lamina III of the rat spinal cord are selectively innervated by local dynorphin-containing excitatory neurons
Large projection neurons in lamina III of the rat spinal cord that express the neurokinin 1 receptor are densely innervated by peptidergic primary afferent nociceptors and more sparsely by low-threshold myelinated afferents. However, we know little about their input from other glutamatergic neurons. Here we show that these cells receive numerous contacts from nonprimary boutons that express the vesicular glutamate transporter 2 (VGLUT2), and form asymmetrical synapses on their dendrites and cell bodies. These synapses are significantly smaller than those formed by peptidergic afferents, but provide a substantial proportion of the glutamatergic synapses that the cells receive (over a third of those in laminae I–II and half of those in deeper laminae). Surprisingly, although the dynorphin precursor preprodynorphin (PPD) was only present in 4–7% of VGLUT2 boutons in laminae I–IV, it was found in 58% of the VGLUT2 boutons that contacted these cells. This indicates a highly selective targeting of the lamina III projection cells by glutamatergic neurons that express PPD, and these are likely to correspond to local neurons (interneurons and possibly projection cells). Since many PPD-expressing dorsal horn neurons respond to noxious stimulation, this suggests that the lamina III projection cells receive powerful monosynaptic and polysynaptic nociceptive input. Excitatory interneurons in the dorsal horn have been shown to possess IA currents, which limit their excitability and can underlie a form of activity-dependent intrinsic plasticity. It is therefore likely that polysynaptic inputs to the lamina III projection neurons are recruited during the development of chronic pain states
Quark mass dependence of the vacuum electric conductivity induced by the magnetic field in SU(2) lattice gluodynamics
We study the electric conductivity of the vacuum of quenched SU(2) lattice
gauge theory induced by the magnetic field B as a function of the bare quark
mass m. The conductivity grows as the quark mass decreases. Simplest power-like
fit indicates that the conductivity behaves as B/sqrt(m). We discuss the
implications of this result for dilepton angular distributions in heavy ion
collisions.Comment: 5 pages RevTeX, 4 figure
Leptogenesis and Low energy CP violation, a link
How is CP violation of low energy related to CP violation required from
baryon number asymmetry ? We give an example which shows a direct link between
CP violation of neutrino oscillation and baryogenesis through leptogenesis.Comment: 3 pages and 2 figures, Talk presented at 4th Nufac02, July 1-6, 200
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