1,866 research outputs found

    Non-Hermitian Floquet Topological Matter -- A Review

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    Non-Hermitian Floquet topological phases appear in systems described by time-periodic non-Hermitian Hamiltonians. This review presents a sum-up of our studies on non-Hermitian Floquet topological matter in one and two spatial dimensions. After a brief overview of the literature, we introduce our theoretical framework for the study of non-Hermitian Floquet systems and the topological characterization of non-Hermitian Floquet bands. Based on our theories, we describe typical examples of non-Hermitian Floquet topological insulators, superconductors and quasicrystals with a focus on their topological invariants, bulk-edge correspondences, non-Hermitian skin effects, dynamical properties and localization transitions. We conclude this review by summarizing our main discoveries and discussing potential future directions.Comment: 86 pages, 10 figures, comments are welcom

    Phosphatidylinositol 3-Kinase Plays a Vital Role in Regulation of Rice Seed Vigor via Altering NADPH Oxidase Activity

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    Phosphatidylinositol 3-kinase (PI3K) has been reported to be important in normal plant growth and stress responses. In this study, it was verified that PI3K played a vital role in rice seed germination through regulating NADPH oxidase activity. Suppression of PI3K activity by inhibitors wortmannin or LY294002 could abate the reactive oxygen species (ROS) formation, which resulted in disturbance to the seed germination. And then, the signal cascades that PI3K promoted the ROS liberation was also evaluated. Diphenylene iodonium (DPI), an NADPH oxidase inhibitor, suppressed most of ROS generation in rice seed germination, which suggested that NADPH oxidase was the main source of ROS in this process. Pharmacological experiment and RT-PCR demonstrated that PI3K promoted the expression of Os rboh9. Moreover, functional analysis by native PAGE and the measurement of the 2, 3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazo-lium-5- carboxanilide (XTT) formazan concentration both showed that PI3K promoted the activity of NADPH oxidase. Furthermore, the western blot analysis of OsRac-1 demonstrated that the translocation of Rac-1 from cytoplasm to plasma membrane, which was known as a key factor in the assembly of NADPH oxidase, was suppressed by treatment with PI3K inhibitors, resulting in the decreased activity of NADPH oxidase. Taken together, these data favored the novel conclusion that PI3K regulated NADPH oxidase activity through modulating the recruitment of Rac-1 to plasma membrane and accelerated the process of rice seed germination

    A γ\gamma-ray Quasi-Periodic modulation in the Blazar PKS 0301−-243?

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    We report a nominally high-confidence γ\gamma-ray quasi-periodic modulation in the blazar PKS 0301−-243. For this target, we analyze its \emph{Fermi}-LAT Pass 8 data covering from 2008 August to 2017 May. Two techniques, i.e., the maximum likelihood optimization and the exposure-weighted aperture photometry, are used to build the γ\gamma-ray light curves. Then both the Lomb-Scargle Periodogram and the Weighted Wavelet Z-transform are applied to the light curves to search for period signals. A quasi-periodicity with a period of 2.1±0.32.1\pm0.3 yr appears at the significance level of ∼5σ\sim5\sigma, although it should be noted that this putative quasi-period variability is seen in a data set barely four times longer. We speculate that this γ\gamma-ray quasi-periodic modulation might be evidence of a binary supermassive black hole.Comment: 9 pages, 8 figures; Accepted for publication in Ap

    Filament L1482 in the California molecular cloud

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    Aims. The process of gravitational fragmentation in the L1482 molecular filament of the California molecular cloud is studied by combining several complementary observations and physical estimates. We investigate the kinematic and dynamical states of this molecular filament and physical properties of several dozens of dense molecular clumps embedded therein. Methods. We present and compare molecular line emission observations of the J=2--1 and J=3--2 transitions of 12CO in this molecular complex, using the KOSMA 3-meter telescope. These observations are complemented with archival data observations and analyses of the 13CO J=1--0 emission obtained at the Purple Mountain Observatory 13.7-meter radio telescope at Delingha Station in QingHai Province of west China, as well as infrared emission maps from the Herschel Space Telescope online archive, obtained with the SPIRE and PACS cameras. Comparison of these complementary datasets allow for a comprehensive multi-wavelength analysis of the L1482 molecular filament. Results. We have identified 23 clumps along the molecular filament L1482 in the California molecular cloud. All these molecular clumps show supersonic non-thermal gas motions. While surprisingly similar in mass and size to the much better known Orion molecular cloud, the formation rate of high-mass stars appears to be suppressed in the California molecular cloud relative to that in the Orion molecular cloud based on the mass-radius threshold derived from the static Bonnor Ebert sphere. Our analysis suggests that these molecular filaments are thermally supercritical and molecular clumps may form by gravitational fragmentation along the filament. Instead of being static, these molecular clumps are most likely in processes of dynamic evolution.Comment: 10 pages, 9 figures, 2 tables, accepted to Astronomy and Astrophysic

    A saúde mental é o fator mais importante que influencia a qualidade de vida de idosos deixados para trás quando as famílias emigram da China rural

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    OBJECTIVES: to investigate the quality of life and the associated factors on left behind elderly in rural China. METHOD: the research was conducted cluster sampling to select 456 elderly left behind when family members migrated out of rural China to participate in a cross-sectional study by completing a general data questionnaire and Quality of Life questionnaire. RESULTS: 91.5% of the elderly requested psychological counseling and education. For the elderly, scores for mental health (39.56±13.73) were significantly lower compared with Chinese standard data (61.6±13.7) (POBJETIVOS: investigar la calidad de vida y los factores asociados a los adultos mayores que se quedan en las zonas rurales de China. MÉTODO: la investigación se realizó por medio de muestreo por conglomerados para seleccionar 456 adultos mayores que se quedaron cuando los miembros de la familia emigraron de zonas rurales de China, para participar en un estudio de corte transversal, completando un cuestionario de datos generales y cuestionario de calidad de vida. RESULTADOS: el 91.5% de los adultos mayores solicitó asistencia psicológica y educación. Para los adultos mayores, las puntuaciones de salud mental (39.56±13.73) fueron significativamente más bajos en comparación con los datos estándar de China (61.6±13.7) (pOBJETIVOS: investigar a qualidade de vida e fatores associados de idosos deixados para trás na China rural. MÉTODO: foi realizada amostragem por conglomerado para selecionar 456 idosos deixados para trás quando os membros da família emigram da China rural. Este é um estudo transversal com preenchimento de um questionário de dados gerais e de qualidade de vida. RESULTADOS: 91,5% dos idosos convidados solicitaram aconselhamento e educação psicológicos. Para os idosos, os escores de saúde mental (39,56±13,73) foram significativamente menores em comparação aos dados padrões chineses (61,6±13,7) (
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