The electronic orders in Hubbard models on a Kagome lattice at van Hove filling are of intense current interest and debate. We study this issue using the singular-mode functional renormalization group theory. We discover a rich variety of electronic instabilities under short range interactions. With increasing on-site repulsion U , the system develops successively ferromagnetism, intra unitcell antiferromagnetism, and charge bond order. With nearest-neighbor Coulomb interaction V alone (U = 0), the system develops intra-unit-cell charge density wave order for small V , s−wave superconductivity for moderate V , and the charge density wave order appears again for even larger V . With both U and V , we also find spin bond order and chiral d x 2 −y 2 + idxy superconductivity in some particular regimes of the phase diagram. We find that the s-wave superconductivity is a result of charge density wave fluctuations and the squared logarithmic divergence in the pairing susceptibility. On the other hand, the d-wave superconductivity follows from bond order fluctuations that avoid the matrix element effect. The phase diagram is vastly different from that in honeycomb lattices because of the geometrical frustration in the Kagome lattice.
We study the electronic instabilities of near 1/4 electron doped graphene using the singular-mode functional renormalization group, with a self-adaptive k-mesh to improve the treatment of the van Hove singularities, and variational Monte-Carlo method. At 1/4 doping the system is a chiral spin density wave state exhibiting the anomalous quantized Hall effect. When the doping drops below 1/4, the d x 2 −y 2 + idxy Cooper pairing becomes the leading instability. Our results suggest that near 1/4 electron-or hole-doping (away from the neutral point) the graphene is either a Chern insulator or a topoligical superconductor.
In several recent experiments the superconducting gap of a single-unit-cell-thick FeSe film on SrTiO 3 substrate has been observed by scanning tunneling spectroscopy and angle-resolved photoemission spectroscopy. The value of the superconducting gap is about nine times larger than that of the bulk FeSe under ambient pressure, suggesting a much higher pairing energy scale and T c than all other iron-based superconductors and thus calling for a better understanding of its superconducting mechanism. In this paper we study the effects of screening due to the SrTiO 3 ferroelectric phonons on Cooper pairing in FeSe. We conclude that it can significantly enhance the energy scale of Cooper pairing and even change the pairing symmetry. Our results also raise some concerns on whether phonons can be completely ignored for bulk iron-based superconductors.
We investigated the transcriptional mechanism underlying lung cancer development. RNA sequencing analysis was performed on blood samples from lung cancer cases and healthy controls. Differentially expressed microRNAs (miRNAs), circular RNAs (circRNAs), mRNAs (genes), and long non-coding RNAs (lncRNA) were identified, followed by pathway enrichment analysis. Based on miRNA target interactions, a competing endogenous network was established and significant nodes were screened. Differentially expressed transcriptional factors were retrieved from the TRRUST database and the transcriptional factor regulatory network was constructed. The expression of 59 miRNAs, 18,306 genes,232 lncRNAs, and 292 circRNAs were greatly altered in patients with lung cancer. miRNAs were closely associated with cancer-related pathways, such as pathways in cancer, colorectal cancer, and transcriptional misregulation in cancer. Two novel pathways, olfactory transduction and neuroactive ligand-receptor interactions, were significantly enriched by differentially expressed genes. The competing endogenous RNA network revealed 5 hub miRNAs. Hsa-miR-582-3p and hsa-miR-582-5p were greatly enriched in the Wnt signaling pathway. Hsa-miR-665 was closely related with the MAPK signaling pathway. Hsa-miR-582-3p and hsa-miR-582-5p were also present in the TF regulatory network. Transcriptional factors of WT1 (wilms tumor 1) and ETV1 (ETS variant 1) were regulated by hsa-miR-657 and hsa-miR-582-5p, respectively, and controlled androgen receptor gene expression. miR-582-5p, miRNA-582-3p, and miR-657 may play critical regulatory roles in lung tumor development. Our work may explore new mechanism of lung cancer and aid the development of novel therapy.
As the challenge of mental health problems such as anxiety and depression increasing today, more convenient, objective, real-time assessing techniques of mental state are in need. The Microsoft Kinect camera is a possible option for contactlessly capturing human gait, which could reflect the walkers’ mental state. So we tried to propose a novel method for monitoring individual’s anxiety and depression based on the Kinect-recorded gait pattern. In this study, after finishing the 7-item Generalized Anxiety Disorder Scale (GAD-7) and the 9-item Patient Health Questionnaire (PHQ-9), 179 participants were required to walked on the footpath naturally while shot by the Kinect cameras. Fast Fourier Transforms (FFT) were conducted to extract features from the Kinect-captured gait data after preprocessing, and different machine learning algorithms were used to train the regression models recognizing anxiety and depression levels, and the classification models detecting the cases with specific depressive symptoms. The predictive accuracies of the regression models achieved medium to large level: The correlation coefficient between predicted and questionnaire scores reached 0.51 on anxiety (by epsilon-Support Vector Regression, e-SVR) and 0.51 on depression (by Gaussian Processes, GP). The predictive accuracies could be even higher, 0.74 on anxiety (by GP) and 0.64 on depression (by GP), while training and testing the models on the female sample. The classification models also showed effectiveness on detecting the cases with some symptoms. These results demonstrate the possibility to recognize individual’s questionnaire measured anxiety/depression levels and some depressive symptoms based on Kinect-recorded gait data through machine learning method. This approach shows the potential to develop non-intrusive, low-cost methods for monitoring individuals’ mental health in real time.
We show that the newly discovered BiS2-based superconductors may have a dominant triplet pairing component, in addition to a subdominant singlet component arising from the spin-orbital coupling. The pairing respects time-reversal symmetry. The dominant triplet gap causes gap sign changes between the spin-split Fermi pockets. Within a pocket, the gap function respects d * x 2 −y 2wave symmetry, where the star indicates joint spin-lattice rotations. Below the Lifshitz filling level the gap is nodelss and the superconducting state is weak topological. Above the Lifshitz points the gap becomes nodal. The dominant triplet pairing is consistent with the experimental upper critical field exceeding the Pauli limit.
Facing the challenging employment situation and the changing labor market, developing student entrepreneurial intention has attracted significant policy consideration in China. This study describes the background of entrepreneurship education in China’s higher education institutes and explores the influences of entrepreneurship education on student entrepreneurial intention. Using data from a survey on students in China, this study finds that students in different types of institutions and different major fields had a different level of engagement in entrepreneurship education. Further, the higher the level of entrepreneurship education the students received, the stronger their self-efficacy of entrepreneurial decision-making was, and the stronger their entrepreneurial intention was. Student entrepreneurial decision-making self-efficacy played a mediating role between entrepreneurship education and student entrepreneurial intention. We found that entrepreneurship education has a positive effect on entrepreneurial intention. Entrepreneurship education course-taking has a positive effect on entrepreneurial decision-making. Furthermore, the positive effect of self-efficacy of entrepreneurial decision-making on entrepreneurial intention was also confirmed. We also found that self-efficacy of entrepreneurial decision-making played the significant role of mediator between entrepreneurship education and entrepreneurial intention. The findings also showed a difference between the current China context and the western context that taking entrepreneurship-related classes had more considerable influences on student entrepreneurial intention than entrepreneurship-related practicum. We discuss the implications of the improvement of higher education in China and relevance to other contexts.
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