Standard Model With Higgs As Gauge Field On Fourth Homotopy Group

Based upon a first principle, the generalized gauge principle, we construct a general model with $G_L\times G'_R \times Z_2$ gauge symmetry, where $Z_2=\pi_4(G_L)$ is the fourth homotopy group of the gauge group $G_L$, by means of the non-commutative differential geometry and reformulate the Weinberg-Salam model and the standard model with the Higgs field being a gauge field on the fourth homotopy group of their gauge groups. We show that in this approach not only the Higgs field is automatically introduced on the equal footing with ordinary Yang-Mills gauge potentials and there are no extra constraints among the parameters at the tree level but also it most importantly is stable against quantum correlation.Comment: 19 pages, Latex, ASITP-94-2

Design and Performance Analysis for LDPC Coded Modulation in Multiuser MIMO Systems

The channel capacity can be greatly increased by using multiple transmit and receive antennas, which is usually called multi-input multi-output (MIMO) systems. Iterative processing has achieved near-capacity on a single-antenna Gaussian or Rayleigh fading channel. How to use the iterative technique to exploit the capacity potential in single-user and/or multiuser MIMO systems is of great interest. We propose a low-density parity-check (LDPC) coded modulation scheme in multiuser MIMO systems. The receiver can be regarded as a serially concatenated iterative detection and decoding scheme, where the LDPC decoder performs the role of outer decoder and the multiuser demapper does that of the inner decoder. For the proposed scheme, appropriate selection of a bit-to-symbol mapping is crucial to achieve a good performance, so we investigate and find the best mapping under various cases.Analytical bound serves as a useful tool to assess system performance. The search for powerful codes has motivated the introduction of efficient bounding techniques tailored to some ensembles of codes. We then investigate combinatorial union bounding techniques for fast fading multiuser MIMO systems. The union upper bound on maximum likelihood (ML) decoding error probability provides a prediction for the system performance, with which the simulated system performance can be compared. Closed-form expression for the union bound is obtained, which can be evaluated efficiently by using a polynomial expansion. In addition, the constrained channel capacity and the threshold obtained from extrinsic information transfer (EXIT) chart can also serve as performance measures. Based on the analysis for fast fading case, we generalize the union upper bound to the block fading case

Sequence variation characteristics of D-loop, rRNA, tRNA, and polypeptide coding region of bovine mitochondrial DNA

By cloning and sequencing the mtDNA of cows from different maternal lineages, it was found that multiple heteroplasmic mtDNA states within the D-loop and rRNA genes of mtDNA existed extensively in Holstein cattle. Meanwhile, the nature and transmission of mtDNA were investigated. The mtDNA population in a specific animal was found to be a mixture of different genotypes. Because heteroplasmy was observed frequently and seemingly is persistent, selected amplification of specific mtDNA molecules may not be a part of mtDNA inheritance. At same time, four hypervariable sites were located at nt 169, 216, and 1594 between nt 352 to 364. The data also suggest that replication slippage might be a common cause of the transversion, insertion, and deletion;In another study, a 3.6 kb bovine mtDNA containing several tRNA and protein coding regions was cloned and sequenced from 13 cows. Four different nucleotide substitutions were detected in these regions. The frequency of nucleotide substitutions in the tRNA and protein coding regions was much less than that in the D-loop and rRNA gene regions. Transition substitution was the major type of variations in the tRNA and protein coding regions. Transitions occurred at the third nucleotide of the codon or in a loop region of tRNA but did not change the amino acid encoded by the codon or the general structure of tRNA. The transversion at nt 9682 from guanine to cytosine was considered to be exception because the conservative amino acid is alanine as based on data from other animal species. Therefore, the true sequence of bovine mtDNA in the germ line could be cytosine at nt 9682, and the originally published sequence could be a rare substitution in the cow that was used. No significant difference could be expected from all the different genotypes of mtDNA in the protein and tRNA coding regions;The data delineated the unique characteristics of mtDNA sequence variations in the D-loop, rRNA, and protein coding regions and provided the evidence of random passing of mtDNA from ancestor to progeny

Complete Cross-triplet Loss in Label Space for Audio-visual Cross-modal Retrieval

The heterogeneity gap problem is the main challenge in cross-modal retrieval. Because cross-modal data (e.g. audiovisual) have different distributions and representations that cannot be directly compared. To bridge the gap between audiovisual modalities, we learn a common subspace for them by utilizing the intrinsic correlation in the natural synchronization of audio-visual data with the aid of annotated labels. TNN-CCCA is the best audio-visual cross-modal retrieval (AV-CMR) model so far, but the model training is sensitive to hard negative samples when learning common subspace by applying triplet loss to predict the relative distance between inputs. In this paper, to reduce the interference of hard negative samples in representation learning, we propose a new AV-CMR model to optimize semantic features by directly predicting labels and then measuring the intrinsic correlation between audio-visual data using complete cross-triple loss. In particular, our model projects audio-visual features into label space by minimizing the distance between predicted label features after feature projection and ground label representations. Moreover, we adopt complete cross-triplet loss to optimize the predicted label features by leveraging the relationship between all possible similarity and dissimilarity semantic information across modalities. The extensive experimental results on two audio-visual double-checked datasets have shown an improvement of approximately 2.1% in terms of average MAP over the current state-of-the-art method TNN-CCCA for the AV-CMR task, which indicates the effectiveness of our proposed model.Comment: 9 pages, 5 figures, 3 tables, accepted by IEEE ISM 202

Breeding of high lipid producing strain of Geotrichum robustum by ion beam implantation

To obtain an industrial strain with high lipid yield, the wild strain G0 of Geotrichum robustum was mutated by means of nitrogen ions implantation. Mutagenic effects of strain G0 by low energy N+ ion implantation were studied. The experimental results indicated that the survival rate curve took a ?saddle? shape, and the positive mutation rate was increased to 22.00% at the dose of nitrogen ions 2.0 x 10(15) ions/cm² when the survival rate was 28.60%. By repeated screening, a high lipid producing strain G9 was obtained. The biomass, lipid content and lipid yield of the mutant can reach 40.25 g/L, 71.14% and 28.63 g/L after cultured in a 5L fermenter for 8 days, increasing by 52.81%, 68.82% and 157.93% to those of wild strain, respectively. Analysis results on fatty acids composition and relative content by gas chromatography and mass spectrometry showed that the lipid in strain G9 was mainly composed of 16-carbon and 18-carbon fatty acids, including 37.360% oleic acid, 23.631% palmitic acid, 4.458% linoleic acid and 26.465% stearic acid. Such compositional features were quite similar to plant oil. Geotrichum robustum strain G9 may be an ideal high lipid producing strain for biodiesel production