599 research outputs found

    Electronic band gaps and transport properties in periodically alternating mono- and bi-layer graphene superlattices

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    We investigate the electronic band structure and transport properties of periodically alternating mono- and bi-layer graphene superlattices (MBLG SLs). In such MBLG SLs, there exists a zero-averaged wave vector (zero-k‟\overline{k}) gap that is insensitive to the lattice constant. This zero-k‟\overline{k} gap can be controlled by changing both the ratio of the potential widths and the interlayer coupling coefficient of the bilayer graphene. We also show that there exist extra Dirac points; the conditions for these extra Dirac points are presented analytically. Lastly, we demonstrate that the electronic transport properties and the energy gap of the first two bands in MBLG SLs are tunable through adjustment of the interlayer coupling and the width ratio of the periodic mono- and bi-layer graphene.Comment: More discussion is added and the English is polished. Accepted for publication in EP

    The ΄(1S)\Upsilon(1S) leptonic decay using the principle of maximum conformality

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    In the paper, we study the ΄(1S)\Upsilon(1S) leptonic decay width Γ(΄(1S)→ℓ+ℓ−)\Gamma(\Upsilon(1S)\to \ell^+\ell^-) by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, Γ΄(1S)→e+e−=1.262−0.175+0.195\Gamma_{\Upsilon(1S) \to e^+ e^-} = 1.262^{+0.195}_{-0.175} keV, where the error is squared average of those from αs(MZ)=0.1181±0.0011\alpha_s(M_{Z})=0.1181\pm0.0011, mb=4.93±0.03m_b=4.93\pm0.03 GeV and the choices of factorization scales within ±10%\pm 10\% of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.Comment: 6 pages, 4 figure

    The heavy quarkonium inclusive decays using the principle of maximum conformality

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    The next-to-next-to-leading order (NNLO) pQCD correction to the inclusive decays of the heavy quarkonium ηQ\eta_Q (QQ being cc or bb) has been done in the literature within the framework of nonrelativistic QCD. One may observe that the NNLO decay width still has large conventional renormalization scale dependence due to its weaker pQCD convergence, e.g. about (−34%+4%)(^{+4\%}_{-34\%}) for ηc\eta_c and (−9%+0.0)(^{+0.0}_{-9\%}) for ηb\eta_b, by varying the scale within the range of [mQ,4mQ][m_Q, 4m_Q]. The principle of maximum conformality (PMC) provides a systematic way to fix the αs\alpha_s-running behavior of the process, which satisfies the requirements of renormalization group invariance and eliminates the conventional renormalization scheme and scale ambiguities. Using the PMC single-scale method, we show that the resultant PMC conformal series is renormalization scale independent, and the precision of the ηQ\eta_Q inclusive decay width can be greatly improved. Taking the relativistic correction O(αsv2)\mathcal{O}(\alpha_{s}v^2) into consideration, the ratios of the ηQ\eta_{Q} decays to light hadrons or γγ\gamma\gamma are: RηcNNLO∣PMC=(3.93−0.24+0.26)×103R^{\rm NNLO}_{\eta_c}|_{\rm{PMC}}=(3.93^{+0.26}_{-0.24})\times10^3 and RηbNNLO∣PMC=(22.85−0.87+0.90)×103R^{\rm NNLO}_{\eta_b}|_{\rm{PMC}}=(22.85^{+0.90}_{-0.87})\times10^3, respectively. Here the errors are for Δαs(MZ)=±0.0011\Delta\alpha_s(M_Z) = \pm0.0011. As a step forward, by applying the Padeˊ\acute{e} approximation approach (PAA) over the PMC conformal series, we obtain approximate NNNLO predictions for those two ratios, e.g. RηcNNNLO∣PAA+PMC=(5.66−0.55+0.65)×103R^{\rm NNNLO}_{\eta_c}|_{\rm{PAA+PMC}} =(5.66^{+0.65}_{-0.55})\times10^3 and RηbNNNLO∣PAA+PMC=(26.02−1.17+1.24)×103R^{\rm NNNLO}_{\eta_b}|_{\rm{PAA+PMC}}=(26.02^{+1.24}_{-1.17})\times10^3. The RηcNNNLO∣PAA+PMCR^{\rm NNNLO}_{\eta_c}|_{\rm{PAA+PMC}} ratio agrees with the latest PDG value Rηcexp=(5.3−1.4+2.4)×103R_{\eta_c}^{\rm{exp}}=(5.3_{-1.4}^{+2.4})\times10^3, indicating the necessity of a strict calculation of NNNLO terms.Comment: 10 pages, 4 figure

    SR140333 counteracts NK-1 mediated cell proliferation in human breast cancer cell line T47D

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    <p>Abstract</p> <p>Background</p> <p>It has been demonstrated that certain NK-1 antagonists could reduce proliferation of several cancer cell lines, however, it is unknown whether SR140333 exerts proliferation inhibition in breast cancer cell line.</p> <p>Methods</p> <p>Immunohistochemical staining was carried out to investigate the immunolocation of NK-1 in breast cancer tissues and T47D cell line, thereafter, various concentrations of [Sar9, Met(O2)11]substance P and SR140333 were applied alone or combined. MTT assay was applied to detect cytoactivation and coulter counter was to detect growth curve. The Hoechst33258 staining was performed to detect apoptosis.</p> <p>Results</p> <p>We found that breast cancer and T47D cells bear positive expression of NK-1. SR140333 inhibited cell growth in a dose dependent manner. Furthermore, SR140333 could counteract [Sar9, Met(O2)11]substance P induced proliferation. Hoechst33258 staining revealed the presence of apoptosis after SR140333 treatment.</p> <p>Conclusions</p> <p>Our study demonstrated SR140333 exert proliferation inhibition in breast cancer cell line T47D and indicates NK-1 play a central role in the substance P related cell proliferation in breast cancer.</p

    Reanalysis of the Gross-Llewellyn Smith sum rule up to O(αs4){\cal O}(\alpha_s^4)-order QCD corrections

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    In the paper, we reanalyze the properties of Gross-Llewellyn Smith (GLS) sum rule by using the O(αs4)\mathcal{O}(\alpha_s^4)-order QCD corrections with the help of principle of maximum conformality (PMC). By using the PMC single-scale approach, we obtain an accurate renormalization scale-and-scheme independent pQCD contribution for GLS sum rule, e.g. SGLS(Q02=3GeV2)∣PMC=2.559−0.024+0.023S^{\rm GLS}(Q_0^2=3{\rm GeV}^2)|_{\rm PMC}=2.559^{+0.023}_{-0.024}, where the error is squared average of those from Δαs(MZ)\Delta\alpha_s(M_Z), the predicted O(αs5)\mathcal{O}(\alpha_s^5)-order terms predicted by using the Pad\'{e} approximation approach. After applying the PMC, a more convergent pQCD series has been obtained, and the contributions from the unknown higher-order terms are highly suppressed. In combination with the nonperturbative high-twist contribution, our final prediction of GLS sum rule agrees well with the experimental data given by the CCFR collaboration.Comment: 6 pages, 5 figure

    Disentangling Writer and Character Styles for Handwriting Generation

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    Training machines to synthesize diverse handwritings is an intriguing task. Recently, RNN-based methods have been proposed to generate stylized online Chinese characters. However, these methods mainly focus on capturing a person's overall writing style, neglecting subtle style inconsistencies between characters written by the same person. For example, while a person's handwriting typically exhibits general uniformity (e.g., glyph slant and aspect ratios), there are still small style variations in finer details (e.g., stroke length and curvature) of characters. In light of this, we propose to disentangle the style representations at both writer and character levels from individual handwritings to synthesize realistic stylized online handwritten characters. Specifically, we present the style-disentangled Transformer (SDT), which employs two complementary contrastive objectives to extract the style commonalities of reference samples and capture the detailed style patterns of each sample, respectively. Extensive experiments on various language scripts demonstrate the effectiveness of SDT. Notably, our empirical findings reveal that the two learned style representations provide information at different frequency magnitudes, underscoring the importance of separate style extraction. Our source code is public at: https://github.com/dailenson/SDT.Comment: accepted by CVPR 2023. Source code: https://github.com/dailenson/SD

    Sequence Characterization of the MC1R Gene in Yak (Poephagus grunniens) Breeds with Different Coat Colors

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    Melanocortin 1 receptor (MC1R) gene plays a key role in determining coat color in several species, including the cattle. However, up to now there is no report regarding the MC1R gene and the potential association of its mutations with coat colors in yak (Poephagus grunniens). In this study, we sequenced the encoding region of the MC1R gene in three yak breeds with completely white (Tianzhu breed) or black coat color (Jiulong and Maiwa breeds). The predicted coding region of the yak MC1R gene resulted of 954 bp, the same to that of the wild-type cattle sequence, with >99% identity. None of the mutation events reported in cattle was found. Comparing the yak obtained sequences, five nucleotide substitutions were detected, which defined three haplotypes (EY1, EY2, and EY3). Of the five mutations, two, characterizing the EY1 haplotype, were nonsynonymous substitutions (c.340C>A and c.871G>A) causing amino acid changes located in the first extracellular loop (p.Q114K) and in the seventh transmembrane region (p.A291T). In silico prediction might indicate a functional effect of the latter substitution. However, all three haplotypes were present in the three yak breeds with relatively consistent frequency distribution, despite of their distinguished coat colors, which suggested that there was no across-breed association between haplotypes or genotypes and black/white phenotypes, at least in the investigated breeds. Other genes may be involved in affecting coat color in the analyzed yaks
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