3,027 research outputs found
Spin alignment of vector meson in e+e- annihilation at Z0 pole
We calculate the spin density matrix of the vector meson produced in e+e-
annihilation at Z^0 pole. We show that the data imply a significant
polarization for the antiquark which is created in the fragmentation process of
the polarized initial quark and combines with the fragmenting quark to form the
vector meson. The direction of polarization is opposite to that of the
fragmenting quark and the magnitude is of the order of 0.5. A qualitative
explanation of this result based on the LUND string fragmentation model is
given.Comment: 15 pages, 2 fgiures; submitted to Phys. Rev.
Spin Alignment of Vector Meson in High Energy Reactions
The recent data on the polarization of vector meson at LEP show that the
vector mesons favor the helicity zero state. We calculate the helicity density
matrix of vector meson which contains a polarized fragmenting quark by adding
the spin of the fragmenting quark and that of the antiquark created in the
fragmentation. The data at LEP imply a significant polarization for the
antiquark in the opposite direction as that of the fragmenting quark. We extend
the calculations to other reactions and make predictions for vector mesons in
deeply inelastic lepton-nucleon scatterings and polarized collisions.Comment: 4 pages,3 figures, Talk given at 3rd Circum-Pan-Pacific Symposium on
"High Energy Spin Physics", Beijing, China, Oct.8-13, 200
How Chief Information Officer Drives Innovation?
Owing to today’s global digital economy, information technology (IT) executives, namely Chief Information Officers (CIOs), play a crucial role in bridging the business and IT by exploiting IT as a strategic differentiator. Equipped with technical background, CIOs are well-positioned to help the firm to gather and utilize information to explore and exploit innovation. The study aims to investigate whether CIOs contributes to a firm’s innovative search. We examine the long-term effects of CIO appointment on the return on innovation investment through research and development (R&D) activities. By employing patent data and a matched sample of U.S. firms between 1995 and 2010, we show that CIO appointment is positively associated with future innovation efficiency. In particular, we find that CIOs in IT firms exerts a stronger influence on the pursuit of innovation. Taken together, our results shed light on the strategic role of CIO in cultivating firm’s innovation capability
Recommended from our members
Metabolic Pathways Enhancement Confers Poor Prognosis in p53 Exon Mutant Hepatocellular Carcinoma.
RNA-Sequencing (RNA-Seq), the most commonly used sequencing application tool, is not only a method for measuring gene expression but also an excellent media to detect important structural variants such as single nucleotide variants (SNVs), insertion/deletion (Indels), or fusion transcripts. The Cancer Genome Atlas (TCGA) contains genomic data from a variety of cancer types and also provides the raw data generated by TCGA consortium. p53 is among the top 10 somatic mutations associated with hepatocellular carcinoma (HCC). The aim of the present study was to analyze concordant different gene profiles and the priori defined set of genes based on p53 mutation status in HCC using RNA-Seq data. In the study, expression profile of 11 799 genes on 42 paired tumor and adjacent normal tissues was collected, processed, and further stratified by the mutated versus normal p53 expression. Furthermore, we used a knowledge-based approach Gene Set Enrichment Analysis (GSEA) to compare between normal and p53 mutation gene expression profiles. The statistical significance (nominal P value) of the enrichment score (ES) genes was calculated. The ranked gene list that reflects differential expression between p53 wild-type and mutant genotypes was then mapped to metabolic process by KEGG, an encyclopedia of genes and genomes to assign functional meanings. These approaches enable us to identify pathways and potential target gene/pathways that are highly expressed in p53 mutated HCC. Our analysis revealed 2 genes, the hexokinase 2 (HK2) and Enolase 1 (ENO1), were conspicuous of red pixel in the heatmap. To further explore the role of these genes in HCC, the overall survival plots by Kaplan-Meier method were performed for HK2 and ENO1 that revealed high HK2 and ENO1 expression in patients with HCC have poor prognosis. These results suggested that these glycolysis genes are associated with mutated-p53 in HCC that may contribute to poor prognosis. In this proof-of-concept study, we proposed an approach for identifying novel potential therapeutic targets in human HCC with mutated p53. These approaches can take advantage of the massive next-generation sequencing (NGS) data generated worldwide and make more out of it by exploring new potential therapeutic targets
MRI Image Segmentation System of Uterine Fibroids Based on AR-Unet Network
Uterine fibroids are the most common benign tumors in female reproductive organs. The segmentation of uterine fibroids is crucial for accurate treatment. This paper proposes a new uterine fibroids MRI T2W image segmentation network AR-Unet (Attention Resnet101-Unet), which uses the deep neural network ResNet101 as the front end of feature extraction, extracts image semantic information, and combines U-net design ideas to build a network structure. The attention gate module is added before the upsampling and downsampling feature maps are spliced. We tested a total of 123 uterine fibroids MRI T2W images from 13 patients. The segmentation results were verified with expert-defined manual segmentation results. The average Dice coefficient, IOU value, sensitivity and specificity of all segmented images were 0.9044, 0.8443, 88.55% and 94.56%, the performance is better than ResNet101-Unet and Attention-Unet models, and finally the network is encapsulated into an auxiliary diagnostic system
Desiccation and cracking behaviour of clay layer from slurry state under wetting-drying cycles
International audienceLaboratory tests were conducted to investigate the effect of wetting-drying (W-D) cycles on the initiation and evolution of cracks in clay layer. Four identical slurry specimens were prepared and subjected to five subsequent W-D cycles. The water evaporation, surface cracks evolution and structure evolution during the W-D cycles were monitored. The effect of W-D cycles on the geometric characteristics of crack patterns was analyzed by image processing. The results show that the desiccation and cracking behaviour was significantly affected by the applied W-D cycles: the measured cracking water content c, surface crack ratio Rsc and final thickness hf of the specimen increased significantly in the first three W-D cycles and then tended to reach equilibrium; the formed crack patterns after the second W-D cycle were more irregular than that after the first W-D cycle; the increase of surface cracks was accompanied by the decrease of pore volume shrinkage during drying. In addition, it was found that the applied W-D cycles resulted in significant rearrangement of specimen structure: the initially homogeneous and non-aggregated structure was converted to a clear aggregated-structure with obvious inter-aggregate pores after the second W-D cycle; the specimen volume generally increased with increasing cycles due to the aggregation and increased porosity. The image analysis results show that the geometric characteristics of crack pattern were significantly influenced by the W-D cycles, but this influence was reduced after the third cycle. This is consistent with the observations over the experiment, and indicates that the image processing can be used for quantitatively analyzing the W-D cycle dependence of clay desiccation cracking behaviour
Time Crystal in a Single-mode Nonlinear Cavity
Time crystal is a class of non-equilibrium phase with broken
time-translational symmetry. Here we demonstrate the time crystal in a
single-model nonlinear cavity. The time crystal originates from the
self-oscillation induced by the linear gain and is stabilized by the nonlinear
damping. We show this time crystal model exhibits four different
characteristics: the emergence of classical limit cycle under the mean-field
approximation, the dissipative gap closing in the thermodynamic limit, the
quantum oscillation in the Husimi function, and the emergence of quantum limit
cycle in the steady state. These properties provide a complete description of
the time crystal and thus pave the way to investigate the time crystal in
nonlinear systems
- …