12,148 research outputs found
Parity-violating coupling constant from the flavor-conserving effective weak chiral Lagrangian
We investigate the parity-violating pion-nucleon-nucleon coupling constant
, based on the chiral quark-soliton model. We employ an effective
weak Hamiltonian that takes into account the next-to-leading order corrections
from QCD to the weak interactions at the quark level. Using the gradient
expansion, we derive the leading-order effective weak chiral Lagrangian with
the low-energy constants determined. The effective weak chiral Lagrangian is
incorporated in the chiral quark-soliton model to calculate the
parity-violating constant . We obtain a value of about
at the leading order. The corrections from the next-to-leading order
reduce the leading order result by about 20~\%.Comment: 12 page
Iterative algorithms for partitioned neural network approximation to partial differential equations
To enhance solution accuracy and training efficiency in neural network
approximation to partial differential equations, partitioned neural networks
can be used as a solution surrogate instead of a single large and deep neural
network defined on the whole problem domain. In such a partitioned neural
network approach, suitable interface conditions or subdomain boundary
conditions are combined to obtain a convergent approximate solution. However,
there has been no rigorous study on the convergence and parallel computing
enhancement on the partitioned neural network approach. In this paper,
iterative algorithms are proposed to address these issues. Our algorithms are
based on classical additive Schwarz domain decomposition methods. Numerical
results are included to show the performance of the proposed iterative
algorithms
Some Identities on the High-Order -Euler Numbers and Polynomials with Weight 0
We construct the th order nonlinear ordinary differential equation related to the generating function of -Euler numbers with weight 0. From this, we derive some identities on -Euler numbers and polynomials of higher order with weight 0
A photonic-crystal optical antenna for extremely large local-field enhancement
We propose a novel design of an all-dielectric optical antenna based on photonic-band-gap confinement. Specifically, we have engineered the photonic-crystal dipole mode to have broad spectral response (Q ~70) and well-directed vertical-radiation by introducing a plane mirror below the cavity. Considerably large local electric-field intensity enhancement ~4,500 is expected from the proposed design for a normally incident planewave. Furthermore, an analytic model developed based on coupled-mode theory predicts that the electric-field intensity enhancement can easily be over 100,000 by employing reasonably high-Q (~10,000) resonators
Algae–bacteria interactions: Evolution, ecology and emerging applications
AbstractAlgae and bacteria have coexisted ever since the early stages of evolution. This coevolution has revolutionized life on earth in many aspects. Algae and bacteria together influence ecosystems as varied as deep seas to lichens and represent all conceivable modes of interactions — from mutualism to parasitism. Several studies have shown that algae and bacteria synergistically affect each other's physiology and metabolism, a classic case being algae–roseobacter interaction. These interactions are ubiquitous and define the primary productivity in most ecosystems. In recent years, algae have received much attention for industrial exploitation but their interaction with bacteria is often considered a contamination during commercialization. A few recent studies have shown that bacteria not only enhance algal growth but also help in flocculation, both essential processes in algal biotechnology. Hence, there is a need to understand these interactions from an evolutionary and ecological standpoint, and integrate this understanding for industrial use. Here we reflect on the diversity of such relationships and their associated mechanisms, as well as the habitats that they mutually influence. This review also outlines the role of these interactions in key evolutionary events such as endosymbiosis, besides their ecological role in biogeochemical cycles. Finally, we focus on extending such studies on algal–bacterial interactions to various environmental and bio-technological applications
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