1,611 research outputs found
Phenolic Characteristics and Antioxidant Activity of Merlot and Cabernet Sauvignon Wines Increase with Vineyard Altitude in a High-altitude Region
Altitude, as an important factor in the expression of terroir, may affect wine quality. We evaluated the effect of altitude and its related climatic conditions on the phenolic characteristics and antioxidant activity of red wines made from grapes originating from high-altitude areas. The content of total phenolic compounds, total flavonoids and total anthocyanins increased with altitude in Merlot (ME) and Cabernet Sauvignon (CS) wines. Cabernet Sauvignon wines showed richer tannins with increasing altitude. Merlot and CS wines from higher altitude vineyards, showed a greater antioxidant capacity. Salicylic acid, syringic acid, caffeic acid, (+)-catechin, (−)-epicatechin, and the sum of individual phenolic compounds in the winesincreased with altitude based on the results of HPLC. The scores of the sensory evaluation of ME wines increased with higher altitude. The highest score was determined for CS wine originating from 2 608 m. A clear grouping of wines according to grape cultivar and vineyard altitude was observed by principal component analysis. Regression analysis showed that altitude, followed by sunshine hours, made the greatest contribution to differences in the phenolic characteristics and antioxidant activity of red wines at different sites in a high-altitude region
The Riesz basis property of the eigenvectors connected to the exponential stability problem of a boundary damped tube carrying the stationary flow of a fluid
In the present paper we study the stability problem for a stretched tube
conveying an ideal fluid with boundary damping. The spectral problem concerns
operator functions of the forms \begin{equation*}
\mathcal{M}\left(\lambda\right)=\lambda^2G+\lambda
D+C\quad\text{and}\quad\mathcal{P}\left(\lambda\right)=\lambda I-T
\end{equation*} taking values in different Hilbert spaces. Thorough analysis is
made of the location and asymptotics of eigenvalues in the complex plane and
Riesz basis property of the corresponding eigenvectors. Well-posedness of the
initial-value problem for the abstract equation \begin{equation*}
\dot{{x}}\left(t\right)=Tx\left(t\right) \end{equation*} is established as well
as expansions of the solutions in terms of eigenvectors and exponential
stability of the corresponding -semigroup
Spectral analysis of a viscoelastic tube conveying fluid with generalised boundary conditions
We study the spectral problem associated with the equation governing the
small transverse motions of a viscoelastic tube of finite length conveying an
ideal fluid. The boundary conditions considered are of general form, accounting
for a combination of elasticity and viscous damping acting on both the slopes
and the displacements of the ends of the tube. These include many standard
boundary conditions as special cases such as the clamped, free, hinged, and
guided conditions. We derive explicit asymptotic formulae for the eigenvalues
for the case of generalised boundary conditions and specialise these results to
the clamped case and the case in which damping acts on the slopes but not on
the displacements. In particular, the dependence of the eigenvalues on the
parameters of the problem is investigated and it is found that all eigenvalues
are located in certain sectorial sets in the complex plane.Comment: typos correcte
3-(2-AminoÂethyl)-2-(4-chloroÂanilino)Âquinazolin-4(3H)-one methanol 0.75-solvate
In the asymmetric unit of the title compound, C16H15ClN4O·0.75CH3OH, there are two independent quinazolin-4(3H)-one molÂecules and one and a half methanol molÂecules. One of the methanol molÂecules is disordered over two positions with equal occupancies. The dihedral angles between the quinazoline ring system and the chloroÂbenzene ring in the two quinazolin-4(3H)-one molÂecules are essentially the same, at 39.83 (1) and 39.84 (1)°. IntraÂmolecular N—H⋯N and O—H⋯O, and interÂmolecular N—H⋯O and N—H⋯N hydrogen bonds are observed. In addition, π–π stacking interÂactions, with centroid-to-centroid distances of 3.654 (1), 3.766 (1) and 3.767 (1) Å, and weak C—H⋯π interÂactions, are observed
DropMessage: Unifying Random Dropping for Graph Neural Networks
Graph Neural Networks (GNNs) are powerful tools for graph representation
learning. Despite their rapid development, GNNs also faces some challenges,
such as over-fitting, over-smoothing, and non-robustness. Previous works
indicate that these problems can be alleviated by random dropping methods,
which integrate noises into models by randomly masking parts of the input.
However, some open-ended problems of random dropping on GNNs remain to solve.
First, it is challenging to find a universal method that are suitable for all
cases considering the divergence of different datasets and models. Second,
random noises introduced to GNNs cause the incomplete coverage of parameters
and unstable training process. In this paper, we propose a novel random
dropping method called DropMessage, which performs dropping operations directly
on the message matrix and can be applied to any message-passing GNNs.
Furthermore, we elaborate the superiority of DropMessage: it stabilizes the
training process by reducing sample variance; it keeps information diversity
from the perspective of information theory, which makes it a theoretical upper
bound of other methods. Also, we unify existing random dropping methods into
our framework and analyze their effects on GNNs. To evaluate our proposed
method, we conduct experiments that aims for multiple tasks on five public
datasets and two industrial datasets with various backbone models. The
experimental results show that DropMessage has both advantages of effectiveness
and generalization
Topological transitions in continuously-deformed photonic crystals
We demonstrate that multiple topological transitions can occur, with
high-sensitivity, by continuous change of the geometry of a simple 2D
dielectric-frame photonic crystal consisting of circular air-holes. By changing
the radii of the holes and/or the distance between them, multiple transitions
between normal and topological photonic band gaps (PBGs) can appear. The
time-reversal symmetric topological PBGs resemble the quantum spin-Hall
insulator of electrons and have two counter-propagating edge states. We search
for optimal topological transitions, i.e., sharp transitions sensitive to the
geometry, and optimal topological PBGs, i.e., large PBGs with clean spectrum of
edge states. Such optimizations reveal that dielectric-frame photonic crystals
are promising for optical sensors and unidirectional waveguides.Comment: submitted to Phys. Rev.
Nucleon-nucleon interaction in the - coupled channel for a pion mass of 469 MeV
In this work, we apply the relativistic chiral nuclear force to describe the
state-of-the-art lattice simulations of the nucleon-nucleon scattering
amplitude. In particular, we focus on the - coupled channel for a
pion mass of 469 MeV. We show that at leading order the relativistic chiral
nuclear force can only describe and up to
MeV, while at the next-to-leading order it can do
much better up to MeV. However, at the
next-to-next-to-leading order, the description deteriorates, which can be
attributed to the fact that the pion-mass dependence of the pion-nucleon
couplings may not be negligible. Furthermore, all the studies
consistently yield negative , contrary to the lattice QCD results
which are positive but consistent with zero. The present study is relevant to a
better understanding of the lattice QCD nucleon-nucleon force and more general
baryon-baryon interactions.Comment: Accepted for publication in PL
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