230 research outputs found
Blockchain Framework for Digital Learning and Information and Communications Technology
At present, the economic ties between countries worldwide are getting closer and closer. In a world where the internet industry is developing rapidly, Digital learning and ICT applications in blockchain have gradually matured. This paper takes digital learning and ICT blockchain application in e-commerce as the main research object, The rapid development of e-commerce has been promoted through the extensive application of digital learning and information and communication technology blockchain in e-commerce. Digital learning and information and communication technology solve the problems of e-commerce payment with encryption characteristics and security and openness in blockchain; At the same time, the information can be traced and cannot be tampered with to solve the quality problem of e-commerce goods. In a real sense to promote the sustainable development of the field of e-commerce, this study provides new ideas and guidance for the blockchain framework of e-learning and ICT in e-commerce
Immunological characterization of stroke-heart syndrome and identification of inflammatory therapeutic targets
Acute cardiac dysfunction caused by stroke-heart syndrome (SHS) is the second leading cause of stroke-related death. The inflammatory response plays a significant role in the pathophysiological process of cardiac damage. However, the mechanisms underlying the braināheart interaction are poorly understood. Therefore, we aimed to analysis the immunological characterization and identify inflammation therapeutic targets of SHS. We analyzed gene expression data of heart tissue 24 hours after induction of ischemia stoke by MCAO or sham surgery in a publicly available dataset (GSE102558) from Gene Expression Omnibus (GEO). Bioinformatics analysis revealed 138 differentially expressed genes (DEGs) in myocardium of MCAO-treated compared with sham-treated mice, among which, immune and inflammatory pathways were enriched. Analysis of the immune cells infiltration showed that the natural killer cell populations were significantly different between the two groups. We identified five DIREGs, Aplnr, Ccrl2, Cdkn1a, Irak2, and Serpine1 and found that their expression correlated with specific populations of infiltrating immune cells in the cardiac tissue. RTāqPCR and Western blot methods confirmed significant changes in the expression levels of Aplnr, Cdkn1a, Irak2, and Serpine1 after MCAO, which may serve as therapeutic targets to prevent cardiovascular complications after stroke
BiERL: A Meta Evolutionary Reinforcement Learning Framework via Bilevel Optimization
Evolutionary reinforcement learning (ERL) algorithms recently raise attention
in tackling complex reinforcement learning (RL) problems due to high
parallelism, while they are prone to insufficient exploration or model collapse
without carefully tuning hyperparameters (aka meta-parameters). In the paper,
we propose a general meta ERL framework via bilevel optimization (BiERL) to
jointly update hyperparameters in parallel to training the ERL model within a
single agent, which relieves the need for prior domain knowledge or costly
optimization procedure before model deployment. We design an elegant meta-level
architecture that embeds the inner-level's evolving experience into an
informative population representation and introduce a simple and feasible
evaluation of the meta-level fitness function to facilitate learning
efficiency. We perform extensive experiments in MuJoCo and Box2D tasks to
verify that as a general framework, BiERL outperforms various baselines and
consistently improves the learning performance for a diversity of ERL
algorithms.Comment: Published as a conference paper at European Conference on Artificial
Intelligence (ECAI) 202
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In Situ TEM Study of the Degradation of PbSe Nanocrystals in Air
PbSe
nanocrystals have attracted widespread attention due to a
variety of potential applications. However, the practical utility
of these nanocrystals has been hindered by their poor air stability,
which induces undesired changes in the optical and electronic properties.
An understanding of the degradation of PbSe nanocrystals when they
are exposed to air is critical for improving the stability and enhancing
their applications. Here, we use in situ transmission electron microscopy
(TEM) with an environmental cell connected to air to study PbSe nanocrystal
degradation triggered by air exposure. We have also conducted a series
of complementary studies, including in situ environmental TEM study
of PbSe nanocrystals exposed to pure oxygen and PbSe nanocrystals
in H2O using a liquid cell, and ex situ experiments, such
as O2 plasma treatment and thermal heating of PbSe nanocrystals
under different air exposure. Our in situ observations reveal that
when PbSe nanocrystals are exposed to air (or oxygen) under electron
beam irradiation, they experience a series of changes, including shape
evolution of individual nanocrystals with the cuboid intermediates,
coalescence between nanocrystals, and formation of PbSe thin films
through drastic solid-state fusion. Further studies show that the
PbSe thin films transform into an amorphous Pb rich phase or eventually
pure Pb, which suggest that Se reacts with oxygen and can be evaporated
under electron beam illumination. These various in situ and ex situ
experimental results indicate that PbSe nanocrystal degradation in
air is initiated by the dissociation and removal of ligands from the
PbSe nanocrystal surface
Nonlinear Gossip Algorithms for Wireless Sensor Networks
We study some nonlinear gossip algorithms for wireless sensor networks. Firstly, two types of nonlinear single gossip algorithms are proposed. By using Lyapunov theory, Lagrange mean value theorem, and stochastic Lasalleās invariance principle, we prove that the nonlinear single gossip algorithms can converge to the average of initial states with probability one. Secondly, two types of nonlinear multigossip algorithms are also presented and the convergence is proved by the same methods. Finally, computer simulation is also given to show the validity of the theoretical results
A Mode-Sum Prescription for Vacuum Polarization in Even Dimensions
We present a mode-sum regularization prescription for computing the vacuum
polarization of a scalar field in static spherically-symmetric black hole
spacetimes in even dimensions. This is the first general and systematic
approach to regularized vacuum polarization in higher even dimensions, building
upon a previous scheme we developed for odd dimensions. Things are more
complicated here since the even-dimensional propagator possesses logarithmic
singularities which must be regularized. However, in spite of this
complication, the regularization parameters can be computed in closed form in
arbitrary even dimensions and for arbitrary metric function . As an
explicit example of our method, we show plots for vacuum polarization of a
massless scalar field in the Schwarzschild-Tangherlini spacetime for even
. However, the method presented applies straightforwardly to
massive fields or to nonvacuum spacetimes.Comment: arXiv admin note: text overlap with arXiv:1609.0816
Quantum Stress: Density Functional Theory Formulation and Physical Manifestation
The concept of "quantum stress (QS)" is introduced and formulated within
density functional theory (DFT), to elucidate extrinsic electronic effects on
the stress state of solids and thin films in the absence of lattice strain. A
formal expression of QS (\sigma^Q) is derived in relation to deformation
potential of electronic states ({\Xi}) and variation of electron density
({\Delta}n), \sigma^Q = {\Xi}{\Delta}n, as a quantum analog of classical Hook's
law. Two distinct QS manifestations are demonstrated quantitatively by DFT
calculations: (1) in the form of bulk stress induced by charge carriers; and
(2) in the form of surface stress induced by quantum confinement. Implications
of QS in some physical phenomena are discussed to underlie its importance.Comment: 5 pages, 4 figure
FGF: A web tool for Fishing Gene Family in a whole genome database
Gene duplication is an important process in evolution. The availability of genome sequences of a number of organisms has made it possible to conduct comprehensive searches for duplicated genes enabling informative studies of their evolution. We have established the FGF (Fishing Gene Family) program to efficiently search for and identify gene families. The FGF output displays the results as visual phylogenetic trees including information on gene structure, chromosome position, duplication fate and selective pressure. It is particularly useful to identify pseudogenes and detect changes in gene structure. FGF is freely available on a web server at http://fgf.genomics.org.cn
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