104 research outputs found
V2X Content Distribution Based on Batched Network Coding with Distributed Scheduling
Content distribution is an application in intelligent transportation system
to assist vehicles in acquiring information such as digital maps and
entertainment materials. In this paper, we consider content distribution from a
single roadside infrastructure unit to a group of vehicles passing by it. To
combat the short connection time and the lossy channel quality, the downloaded
contents need to be further shared among vehicles after the initial
broadcasting phase. To this end, we propose a joint infrastructure-to-vehicle
(I2V) and vehicle-to-vehicle (V2V) communication scheme based on batched sparse
(BATS) coding to minimize the traffic overhead and reduce the total
transmission delay. In the I2V phase, the roadside unit (RSU) encodes the
original large-size file into a number of batches in a rateless manner, each
containing a fixed number of coded packets, and sequentially broadcasts them
during the I2V connection time. In the V2V phase, vehicles perform the network
coded cooperative sharing by re-encoding the received packets. We propose a
utility-based distributed algorithm to efficiently schedule the V2V cooperative
transmissions, hence reducing the transmission delay. A closed-form expression
for the expected rank distribution of the proposed content distribution scheme
is derived, which is used to design the optimal BATS code. The performance of
the proposed content distribution scheme is evaluated by extensive simulations
that consider multi-lane road and realistic vehicular traffic settings, and
shown to significantly outperform the existing content distribution protocols.Comment: 12 pages and 9 figure
Electrical Tunable Spintronic Neuron with Trainable Activation Function
Spintronic devices have been widely studied for the hardware realization of
artificial neurons. The stochastic switching of magnetic tunnel junction driven
by the spin torque is commonly used to produce the sigmoid activation function.
However, the shape of the activation function in previous studies is fixed
during the training of neural network. This restricts the updating of weights
and results in a limited performance. In this work, we exploit the physics
behind the spin torque induced magnetization switching to enable the dynamic
change of the activation function during the training process. Specifically,
the pulse width and magnetic anisotropy can be electrically controlled to
change the slope of activation function, which enables a faster or slower
change of output required by the backpropagation algorithm. This is also
similar to the idea of batch normalization that is widely used in the machine
learning. Thus, this work demonstrates that the algorithms are no longer
limited to the software implementation. They can in fact be realized by the
spintronic hardware using a single device. Finally, we show that the accuracy
of hand-written digit recognition can be improved from 88% to 91.3% by using
these trainable spintronic neurons without introducing additional energy
consumption. Our proposals can stimulate the hardware realization of spintronic
neural networks.Comment: 26 pages, 9 figure
Impact of lifestyle and psychological resilience on survival among the oldest-old in China: a cohort study
IntroductionHealthy lifestyles and psychological resilience are important factors influencing the life expectancy of the oldest-old (≥80 years). Stratified by urban and rural groups, this study used a 10-year cohort to examine the mechanism of lifestyle and psychological resilience on the survival of the oldest-old in China.MethodsThis study used the China Longitudinal Healthy Longevity Survey datasets spanning from 2008 to 2018, and 9,250 eligible participants were included. The primary outcome variable was all-cause mortality, and independent variables included healthy lifestyle index and psychological resilience. Six covariates were included in the survival analysis and moderation-mediation model, such as gender and annual household income.ResultsThis study found that the oldest-old with five healthy lifestyles had the longest survival time, averaging 59.40 months for urban individuals and 50.08 months for rural individuals. As the lifestyle index increased, the survival rate significantly increased. The Cox regression showed that for the urban oldest-old, the lifestyle index served as a protective factor for survival outcomes. However, this effect lost statistical significance among rural oldest-old individuals. For urban oldest-old individuals, psychological resilience significantly mediated and moderated the effect of the lifestyle index on survival status, but the moderating effect was not statistically significant for the rural ones.DiscussionOverall, healthy lifestyles and psychological resilience can be effective in enhancing the survival of the oldest-old, and there are differences between urban and rural population, so different interventions should be adopted for urban and rural areas to achieve longer life in China
Parity Splitting and Polarized-Illumination Selection of Plasmonic Higher-Order Topological States
Topological states, originated from interactions between internal degree of
freedoms (like spin and orbital) in each site and crystalline symmetries, offer
a new paradigm to manipulate electrons and classical waves. The accessibility
of spin degree of freedom has motivated much attention on spin-related
topological physics. However, intriguing topological physics related to
atomic-orbital parity, another binary degree of freedom, have not been
exploited since accessing approaches on atomic orbitals are not well developed.
Here, we theoretically discover spectral splitting of
atomic-orbital-parity-dependent second-order topological states on a
designer-plasmonic Kagome metasurface, and experimentally demonstrate it by
exploiting the easy controllability of metaatoms. Unlike previous
demonstrations on Hermitian higher-order topological insulators, radiative
non-Hermicity of the metasurface enables far-field access into
metaatomic-orbital-parity-dependent topological states with polarized
illuminations. The atomic-orbital parity degree of freedom may generate more
intriguing topological physics by interacting with different crystalline
symmetries, and promise applications in polarization-multiplexing topological
lasing and quantum emitters.Comment: 19 pages, 4 figure
Free fatty acid hydrolyzed with lipases and their effects on enzyme-modified cheese flavor
peer reviewed: This study investigated the effects of five lipases on enzyme-modified cheese (EMC) flavor development. Results showed that
lipase 30SD contained high hydrolytic activity for short, medium, and long-chain fatty acids within 24 h incubation time, and the highest
content of them among different times could reach 47.24, 475.90, 1 563.92 mg/100 g fat, respectively. Lipase DF15 and MER showed
moderate capacity to hydrolyze volatile fatty acids, while lipase F3G had a stronger ability to produce long-chain fatty acids. Twenty-seven
new volatiles were formed during lipolysis, most of them were acids and esters. Principal component analysis results showed that EMC
produced by lipase 30SD for 18 h was similar to the commercial product with a pungent, rancid, and cheddar flavor. EMCs produced by
lipase DF15 were significantly distinguished from other products by their high content of ethyl heptanoate, ethyl nonanoate, and ethyl
tridecanoate. The findings might be useful for the researchers who focus on lipolysis or EMC product
Integrated Genomic Analysis of the Ubiquitin Pathway across Cancer Types
Protein ubiquitination is a dynamic and reversibleprocess of adding single ubiquitin molecules orvarious ubiquitin chains to target proteins. Here,using multidimensional omic data of 9,125 tumorsamples across 33 cancer types from The CancerGenome Atlas, we perform comprehensive molecu-lar characterization of 929 ubiquitin-related genesand 95 deubiquitinase genes. Among them, we sys-tematically identify top somatic driver candidates,including mutatedFBXW7with cancer-type-specificpatterns and amplifiedMDM2showing a mutuallyexclusive pattern withBRAFmutations. Ubiquitinpathway genes tend to be upregulated in cancermediated by diverse mechanisms. By integratingpan-cancer multiomic data, we identify a group oftumor samples that exhibit worse prognosis. Thesesamples are consistently associated with the upre-gulation of cell-cycle and DNA repair pathways, char-acterized by mutatedTP53,MYC/TERTamplifica-tion, andAPC/PTENdeletion. Our analysishighlights the importance of the ubiquitin pathwayin cancer development and lays a foundation fordeveloping relevant therapeutic strategies
Molecular characterization and clinical relevance of metabolic expression subtypes in human cancers.
Metabolic reprogramming provides critical information for clinical oncology. Using molecular data of 9,125 patient samples from The Cancer Genome Atlas, we identified tumor subtypes in 33 cancer types based on mRNA expression patterns of seven major metabolic processes and assessed their clinical relevance. Our metabolic expression subtypes correlated extensively with clinical outcome: subtypes with upregulated carbohydrate, nucleotide, and vitamin/cofactor metabolism most consistently correlated with worse prognosis, whereas subtypes with upregulated lipid metabolism showed the opposite. Metabolic subtypes correlated with diverse somatic drivers but exhibited effects convergent on cancer hallmark pathways and were modulated by highly recurrent master regulators across cancer types. As a proof-of-concept example, we demonstrated that knockdown of SNAI1 or RUNX1—master regulators of carbohydrate metabolic subtypes-modulates metabolic activity and drug sensitivity. Our study provides a system-level view of metabolic heterogeneity within and across cancer types and identifies pathway cross-talk, suggesting related prognostic, therapeutic, and predictive utility
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
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