734 research outputs found

    A new unique leafhopper genus of Erythroneurini from Thailand, with the description of one new species (Hemiptera, Cicadellidae, Typhlocybinae)

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    A new genus of the leafhopper tribe Erythroneurini (Cicadellidae, Typhlocybinae) from Thailand, Undulivena gen. n., and a new species Undulivena thaiensis sp. n., are described and illustrated. The new genus exhibits a unique feature of the forewing venation with CuA vein strongly sinuate

    Revealing the Empty-State Electronic Structure of Single-Unit-Cell FeSe/SrTiO3_{3}

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    We use scanning tunneling spectroscopy to investigate the filled and empty electronic states of superconducting single-unit-cell FeSe deposited on SrTiO3_3(001). We map the momentum-space band structure by combining quasiparticle interference imaging with decay length spectroscopy. In addition to quantifying the filled-state bands, we discover a Γ\Gamma-centered electron pocket 75 meV above the Fermi energy. Our density functional theory calculations show the orbital nature of empty states at Γ\Gamma and suggest that the Se height is a key tuning parameter of their energies, with broad implications for electronic properties.Comment: 5 pages, 5 figure

    Genetic changes in fetal cerebral cortex after maternal exposure to sevoflurane

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    Purpose: To investigate the acute changes in transcriptome of radial glial progenitor cells after maternal exposure to sevoflurane.Methods: Two groups of sample data were collected from the data set in the GEO database. Pregnant mice in sevoflurane group were exposed to 2.5 % sevoflurane for 6 h on day 14.5 of the pregnancy, while the mice in control group were exposed to 100 % oxygen for 6 h. At the end of the exposure period, the cerebral cortex of the two groups of fetuses was isolated and analyzed by RNA sequencing. Differentially expressed genes (DEG) were analyzed using limma package of R language. The Gene Ontology (GO) and KEGG pathway enrichment were based on DEG through a cluster profile package of R. Moreover, protein-protein interactions (PPI) network construction and central gene prediction were carried out using a string database and R package.Results: Bioinformatics analysis revealed 289 up-regulated genes and 311 down-regulated DEGs, respectively. Gene Ontology and KEGG enrichment analysis revealed terms related to neural development and transcriptional function. Based on the central genes of the PPI network, it was found that certain genes may play significant roles in the regulation of neural development. These genes are hnRNPM, AURKA, NCBP, SRSF6, ASF1B, HNRNPA2B1, DDX21, H3F3B, KPNA2 and ABCE1 (p < 0.05).Conclusion: The findings of this study suggest that hub genes and a variety of signal pathways may play key roles in the development of radial glial progenitor cells

    Strong Majorana evidence of a vortex from scanning tunneling microscopy with a dissipative environment

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    It is predicted that a vortex in a topological superconductor contains a Majorana zero mode (MZM). The confirmative Majorana signature, i.e., the 2e2/h2e^2/h quantized conductance, however is easily sabotaged by unavoidable interruptions, e.g. instrument broadening, non-Majorana signal, and extra particle channels. We propose to avoid the signal interruption by introducing disorder-induced dissipation that couples to the tip-sample tunneling. With dissipation involved, we highlight three features, each of which alone can provide a strong evidence to identify MZM. Firstly, dissipation suppresses a finite-energy Caroli-de Gennes-Matricon (CdGM) conductance peak into a valley, while it does not split MZM zero-bias conductance peak. Secondly, we predict a dissipation-dependent scaling feature of the zero-bias conductance peak. Thirdly, the introduced dissipation manifests the MZM signal by suppressing non-topological CdGM modes. Importantly, the observation of these features does not require a quantized conductance value 2e2/h2e^2/h.Comment: 13 pages, 5 figures with reference list update

    Anisotropic vortex lattice structures in the FeSe superconductor

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    In the recent work by Song et al. [Science 332, 1410 (2011)], the scanning tunneling spectroscopy experiment in the stoichiometric FeSe reveals evidence for nodal superconductivity and strong anisotropy. The nodal structure can be explained with the extended s-wave pairing structure with the mixture of the sx2+y2s_{x^2+y^2} and sx2y2s_{x^2y^2} pairing symmetries. We calculate the anisotropic vortex structure by using the self-consistent Bogoliubov-de Gennes mean-field theory. In considering the absence of magnetic ordering in the FeSe at the ambient pressure, orbital ordering is introduced, which breaks the C4C_4 lattice symmetry down to C2C_2, to explain the anisotropy in the vortex tunneling spectra.Comment: 9 page

    Visualizing the elongated vortices in γ\gamma-Ga nanostrips

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    We study the magnetic response of superconducting γ\gamma-Ga via low temperature scanning tunneling microscopy and spectroscopy. The magnetic vortex cores rely substantially on the Ga geometry, and exhibit an unexpectedly-large axial elongation with aspect ratio up to 40 in rectangular Ga nano-strips (width ll << 100 nm). This is in stark contrast with the isotropic circular vortex core in a larger round-shaped Ga island. We suggest that the unusual elongated vortices in Ga nanostrips originate from geometric confinement effect probably via the strong repulsive interaction between the vortices and Meissner screening currents at the sample edge. Our finding provides novel conceptual insights into the geometrical confinement effect on magnetic vortices and forms the basis for the technological applications of superconductors.Comment: published in Phys. Rev. B as a Rapid Communicatio
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