162 research outputs found

    Six Top Messages of New Physics at the LHC

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    Six top signatures provide a novel probe of new physics. We discuss production of six top quarks as the decay products of a pair of top partners in the setting of a composite Higgs model, and argue that the six top signal may generically provide one of the first final states to show a discrepancy. We construct an analysis based on quantities such as HTH_T and the numbers of jets which are tagged as boosted tops, WWs, or containing bb-tags, and show that the LHC with 3~ab1^{-1} can discover top partners with masses up to around 2.5 TeV in the six top signature.Comment: 15 pages, 6 figures, and 2 table

    Early Development of Graphical Literacy through Knowledge Building

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    This study examined growth in graphical literacy for students contributing to an online, multimedia, communal environment as they advanced their understanding of biology, history and optics. Their science and history studies started early in Grade 3 and continued to the end of Grade 4; students did not receive instruction in graphics production, nor were they required to produce graphics. Results show that students spontaneously produced graphics that advanced along seven dimensions, including effective representation of complex ideas, use of source information and captions, and aesthetic quality. On average, the scores for the seven dimensions were higher for Grade 4 students with two years of experience with Knowledge Building pedagogy and technology (Knowledge Forum®) than for Grade 6 students with one year of experience. The overall pattern of results suggests reciprocal enhancement of graphical, textual, digital, and scientific literacy, with students exceeding expectations by available norms, and performance enhanced through extended Knowledge Building experience

    Blockwise Rank Decoding Problem and LRPC Codes: Cryptosystems with Smaller Sizes

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    In this paper, we initiate the study of the Rank Decoding (RD) problem and LRPC codes with blockwise structures in rank-based cryptosystems. First, we introduce the blockwise errors (\ell-errors) where each error consists of \ell blocks of coordinates with disjoint supports, and define the blockwise RD (\ell-RD) problem as a natural generalization of the RD problem whose solutions are \ell-errors (note that the standard RD problem is actually a special \ell-RD problem with =1\ell=1). We adapt the typical attacks on the RD problem to the \ell-RD problem, and find that the blockwise structures do not ease the problem too much: the \ell-RD problem is still exponentially hard for appropriate choices of >1\ell>1. Second, we introduce blockwise LRPC (\ell-LRPC) codes as generalizations of the standard LPRC codes whose parity-check matrices can be divided into \ell sub-matrices with disjoint supports, i.e., the intersection of two subspaces generated by the entries of any two sub-matrices is a null space, and investigate the decoding algorithms for \ell-errors. We find that the gain of using \ell-errors in decoding capacity outweighs the complexity loss in solving the \ell-RD problem, which makes it possible to design more efficient rank-based cryptosystems with flexible choices of parameters. As an application, we show that the two rank-based cryptosystems submitted to the NIST PQC competition, namely, RQC and ROLLO, can be greatly improved by using the ideal variants of the \ell-RD problem and \ell-LRPC codes. Concretely, for 128-bit security, our RQC has total public key and ciphertext sizes of 2.5 KB, which is not only about 50% more compact than the original RQC, but also smaller than the NIST Round 4 code-based submissions HQC, BIKE, and Classic McEliece

    QCR7 affects the virulence of Candida albicans and the uptake of multiple carbon sources present in different host niches

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    BackgroundCandida albicans is a commensal yeast that may cause life-threatening infections. Studies have shown that the cytochrome b-c1 complex subunit 7 gene (QCR7) of C. albicans encodes a protein that forms a component of the mitochondrial electron transport chain complex III, making it an important target for studying the virulence of this yeast. However, to the best of our knowledge, the functions of QCR7 have not yet been characterized.MethodsA QCR7 knockout strain was constructed using SN152, and BALb/c mice were used as model animals to determine the role of QCR7 in the virulence of C. albicans. Subsequently, the effects of QCR7 on mitochondrial functions and use of carbon sources were investigated. Next, its mutant biofilm formation and hyphal growth maintenance were compared with those of the wild type. Furthermore, the transcriptome of the qcr7Δ/Δ mutant was compared with that of the WT strain to explore pathogenic mechanisms.ResultsDefective QCR7 reduced recruitment of inflammatory cells and attenuated the virulence of C. albicans infection in vivo. Furthermore, the mutant influenced the use of multiple alternative carbon sources that exist in several host niches (GlcNAc, lactic acid, and amino acid, etc.). Moreover, it led to mitochondrial dysfunction. Furthermore, the QCR7 knockout strain showed defects in biofilm formation or the maintenance of filamentous growth. The overexpression of cell-surface-associated genes (HWP1, YWP1, XOG1, and SAP6) can restore defective virulence phenotypes and the carbon-source utilization of qcr7Δ/Δ.ConclusionThis study provides new insights into the mitochondria-based metabolism of C. albicans, accounting for its virulence and the use of variable carbon sources that promote C. albicans to colonize host niches

    Observation and simulation study on the rapid intensification mechanism of Typhoon “Mekkhala” (2006)

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    Based on Doppler Weather radar observations and numerical simulations applying the Weather Research and Forecasting (WRF) system, this study focused on the rapid intensification (RI) of Typhoon “Mekkhala” (2006) in the inshore area in 2020. The simulated track of the typhoon relatively matched with the observation, with a slight eastward bias compared to the observed track. During the phase of RI, there was a slight weakening of vertical wind shear between 200–500 hPa. The temporary decrease in vertical wind shear became a favorable factor for the intensification of the typhoon. In general, vertical wind shear of the lower atmosphere is the key to supporting the RI of Typhoon Mekkhala. In the middle troposphere, the southward component of the vertical wind shear suddenly increases, indicates that the inflow of southern wind to the core of the typhoon had strengthened. Thus, the strengthening of the moisture transport by enhanced southern wind, contributed to the intensification of the typhoon. During the intensification of the typhoon, the low-level vorticity was significantly enhanced, and the high vorticity values expanded from the lower to higher troposphere. The vertical distribution of vorticity transformed from symmetry to asymmetry. The development of secondary circulation on both sides of the typhoon is a dynamic factor for intensification

    Time-Optimal Quantum Driving by Variational Circuit Learning

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    The simulation of quantum dynamics on a digital quantum computer with parameterized circuits has widespread applications in fundamental and applied physics and chemistry. In this context, using the hybrid quantum-classical algorithm, combining classical optimizers and quantum computers, is a competitive strategy for solving specific problems. We put forward its use for optimal quantum control. We simulate the wave-packet expansion of a trapped quantum particle on a quantum device with a finite number of qubits. We then use circuit learning based on gradient descent to work out the intrinsic connection between the control phase transition and the quantum speed limit imposed by unitary dynamics. We further discuss the robustness of our method against errors and demonstrate the absence of barren plateaus in the circuit. The combination of digital quantum simulation and hybrid circuit learning opens up new prospects for quantum optimal control.Comment: 10 pages, 8 figure

    Four Eremophilane Sesquiterpenes from the Mangrove Endophytic Fungus Xylaria sp. BL321

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    Three new eremophilane sesquiterpenes (1–3) were isolated from the mangrove endophytic fungus Xylaria sp. BL321 together with 07H239-A (4), a known analogue of the new compounds. The structures of these compounds were elucidated by analysis of their MS, 1D and 2D NMR spectroscopic data. Compound 4 showed activation activity on α-glucosidase at 0.15 μM (146%), and then, 4 gradually produced inhibitory activity on α-glucosidase with increasing concentration, and the IC50 value is 6.54 μM
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