3,040 research outputs found
Topological linear magnetoresistivity and thermoconductivity induced by noncentrosymmetric Berry curvature
The Berry curvature plays a key role in the magnetic transport of topological
materials. Yet, it is not clear whether the Berry curvature by itself can give
rise to universal transport phenomena with specific scaling behaviors. In this
work, based on the semiclassical Boltzmann formalism and the symmetry analysis,
we show that the noncentrosymmetric distribution of the Berry curvature
generally results in linear magnetoresistivity and thermoconductivity both
exhibiting the B-scaling behavior. We then study such kind of topological
linear magnetoresistivity in the 2D MnBi2Te4 flakes and the 3D
spin-orbit-coupled electron gas, the former showing good agreement with the
experimental observations. The difference between our mechanism and the
conventional anisotropic magnetoresistance is elucidated. Our theory proposes a
universal scenario for the topological linear magnetoresistivity and
thermoconductivity and predicts such effects to occur in various materials,
which also provides a reasonable explanation for the recent observations of
linear magnetoresistivity
Sensitive detection of millimeter wave electric field by driving trapped surface-state electrons
Sensitive detection of electromagnetic wave electric field plays an important
role for electromagnetic communication and sensing. Here, we propose a quantum
sensor to sensitively detect the electric field of the millimeter (mm) wave.
The quantum sensor consists of many surface-state electrons trapped
individually on liquid helium by a scalable electrode-network at the bottom of
the helium film. On such a chip, each of the trapped electrons can be
manipulated by the biased dc-current to deliver the strong spin-orbit
couplings. The mm wave signal to be detected is applied to non-dispersively
drive the orbital states of the trapped electrons, just resulting in the Stark
shifts of the dressed spin-orbital states. As a consequence, the electric field
of the applied mm wave could be detected sensitively by using the spin-echo
interferometry of the long-lived spin states of the electrons trapped on liquid
helium. The reasonable accuracy of the detection and also the feasibility of
the proposal are discussed.Comment: 8 page
Pion Interferometry for Hydrodynamical Expanding Source with a Finite Baryon Density
We calculate the two-pion correlation function for an expanding hadron source
with a finite baryon density. The space-time evolution of the source is
described by relativistic hydrodynamics and the Hanbury-Brown-Twiss (HBT)
radius is extracted after effects of collective expansion and multiple
scattering on the HBT interferometry have been taken into account, using
quantum probability amplitudes in a path-integral formalism. We find that this
radius is substantially smaller than the HBT radius extracted from the
freeze-out configuration.Comment: 4 pages, 2 figure
Remote sensing and social sensing data reveal scale-dependent and system-specific strengths of urban heat island determinants
Urban natural surfaces and non-surface human activities are key factors determining the urban heat island (UHI), but their relative importance remains highly controversial and may vary at different spatial scales and focal urban systems. However, systematic studies on the scale-dependency system-specificity remain largely lacking. Here, we selected 32 major Chinese cities as cases and used Landsat 8 images to retrieve land surface temperature (LST) and quantify natural surface variables using point of interest (POI) data as a measure of the human activity variable and using multiple regression and relative weight analysis to study the contribution and relative importance of these factors to LST at a range of grain sizes (0.25–5 km) and spatial extents (20–60 km). We revealed that the contributions and relative importance of natural surfaces and human activities are largely scale-dependent and system-specific. Natural surfaces, especially vegetation cover, are often the most important UHI determinants for a majority of scales, but the importance of non-surface human activities is increasingly pronounced at a coarser spatial scale with respect to both grain and spatial extent. The scaling relations of the UHI determinants and their relative importance were mostly linear-like at the city-collective level, but highly diverse across individual cities, so reducing non-surface heat emissions could be the most effective measure in particular cases, especially at relatively large spatial scales. This study advances the understanding of UHI formation mechanisms and highlights the complexity of the scale issue underpinning the UHI effect
A real-world observation of antipsychotic effects on brain volumes and intrinsic brain activity in schizophrenia
Background: The confounding effects of antipsychotics that led to the inconsistencies of neuroimaging findings have long been the barriers to understanding the pathophysiology of schizophrenia (SZ). Although it is widely accepted that antipsychotics can alleviate psychotic symptoms during the early most acute phase, the longer-term effects of antipsychotics on the brain have been unclear. This study aims to look at the susceptibility of different imaging measures to longer-term medicated status through real-world observation.
Methods: We compared gray matter volume (GMV) with amplitude of low-frequency fluctuations (ALFFs) in 89 medicated-schizophrenia (med-SZ), 81 unmedicated-schizophrenia (unmed-SZ), and 235 healthy controls (HC), and the differences were explored for relationships between imaging modalities and clinical variables. We also analyzed age-related effects on GMV and ALFF values in the two patient groups (med-SZ and unmed-SZ).
Results: Med-SZ demonstrated less GMV in the prefrontal cortex, temporal lobe, cingulate gyri, and left insula than unmed-SZ and HC (
Conclusion: GMV loss appeared to be pronounced to longer-term antipsychotics, whereby imbalanced alterations in regional low-frequency fluctuations persisted unaffected by antipsychotic treatment. Our findings may help to understand the disease course of SZ and potentially identify a reliable neuroimaging feature for diagnosis
The DNA Methylation Inhibitor Zebularine Controls CD4(+) T Cell Mediated Intraocular Inflammation
CD4+ T cell mediated uveitis is conventionally treated with systemic immunosuppressive agents, including corticosteroids and biologics targeting key inflammatory cytokines. However, their long-term utility is limited due to various side effects. Here, we investigated whether DNA methylation inhibitor zebularine can target CD4+ T cells and control intraocular inflammation. Our results showed that zebularine restrained the expression of inflammatory cytokines IFN-γ and IL-17 in both human and murine CD4+ T cells in vitro. Importantly, it also significantly alleviated intraocular inflammation and retinal tissue damage in the murine experimental autoimmune uveitis (EAU) model in vivo, suggesting that the DNA methylation inhibitor zebularine is a candidate new therapeutic agent for uveitis
Thermodynamics of cosmological horizons in gravity
We explore thermodynamics of the apparent horizon in gravity with both
equilibrium and non-equilibrium descriptions. We find the same dual
equilibrium/non-equilibrium formulation for as for gravity. In
particular, we show that the second law of thermodynamics can be satisfied for
the universe with the same temperature of the outside and inside the apparent
horizon.Comment: 18 pages, no figure, version accepted for publication in JCA
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