95 research outputs found

    Stability range of parameters at fixed points for a class of complex dynamics

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    We study the parameters range for the fixed point of a class of complex dynamics with the rational fractional function as Rn,a,c(z)=zn+azn+cR_{n,a,c}(z)=z^n+\frac{a}{z^n}+c, where n=1,2,3,4n=1,2,3,4 is specified, aa and cc are two complex parameters. The relationship between two parameters, aa and cc, is obtained at the fixed point. Moreover the explicit expression of the parameter aa and cc in terms of Ξ»\lambda is derived, where Ξ»\lambda is the derivative function at fixed point. The parameter regimes for the stability of the fixed point are presented numerically for some typical different cases.Comment: 15 pages, 6 figure

    Development of deformation-tunable quadrupolar microcavity

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    We have developed a technique for realizing a two-dimensional quadrupolar microcavity with its deformation variable from 0% to 20% continuously. We employed a microjet ejected from a noncircular orifice in order to generate a stationary column with modulated quadrupolar deformation in its cross section. Wavelength red shifts of low-order cavity modes due to shape deformation were measured and were found to be in good agreement with the wave calculation for the same deformation, indicating the observed deformation is quadrupolar in nature.Comment: 7 pages, 6 figures, intended for Rev. Sci. Instu

    Chaos-assisted nonresonant optical pumping of quadrupole-deformed microlasers

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    Efficient nonresonant optical pumping of a high-Q scar mode in a two-dimensional quadrupole-deformed microlaser has been demonstrated based on ray and wave chaos. Three-fold enhancement in the lasing power was achieved at a properly chosen pumping angle. The experimental result is consistent with ray tracing and wave overlap integral calculations.Comment: 3 pages, 5 figure

    Magnetic Topological Transistor Exploiting Layer-Selective Transport

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    We propose a magnetic topological transistor based on MnBi2_{2}Te4_{4}, in which the "on" state (quantized conductance) and the "off" state (zero conductance) can be easily switched by changing the relative direction of two adjacent electric fields (parallel vs. antiparallel) applied within a two-terminal junction. We explain that the proposed magnetic topological transistor relies on a novel mechanism due to the interplay of topology, magnetism, and layer degrees of freedom in MnBi2_{2}Te4_{4}. Its performance depends substantially on film thickness and type of magnetic order. We show that "on" and "off" states of the transistor are robust against disorder due to the topological nature of the surface states. Our work opens an avenue for applications of layer-selective transport based on the topological van der Waals antiferromagnet MnBi2_{2}Te4_{4}

    An Updated Search of Steady TeV Ξ³βˆ’\gamma-Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array

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    Using the data taken from Tibet II High Density (HD) Array (1997 February-1999 September) and Tibet-III array (1999 November-2005 November), our previous northern sky survey for TeV Ξ³βˆ’\gamma-ray point sources has now been updated by a factor of 2.8 improved statistics. From 0.0∘0.0^{\circ} to 60.0∘60.0^{\circ} in declination (Dec) range, no new TeV Ξ³βˆ’\gamma-ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV Ξ³βˆ’\gamma-ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits.Comment: This paper has been accepted by hepn

    Insights into salt tolerance from the genome of Thellungiella salsuginea

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    Thellungiella salsuginea, a close relative of Arabidopsis, represents an extremophile model for abiotic stress tolerance studies. We present the draft sequence of the T. salsuginea genome, assembled based on ∼134-fold coverage to seven chromosomes with a coding capacity of at least 28,457 genes. This genome provides resources and evidence about the nature of defense mechanisms constituting the genetic basis underlying plant abiotic stress tolerance. Comparative genomics and experimental analyses identified genes related to cation transport, abscisic acid signaling, and wax production prominent in T. salsuginea as possible contributors to its success in stressful environments

    Oncogenic CagA Promotes Gastric Cancer Risk via Activating ERK Signaling Pathways: A Nested Case-Control Study

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    Background: CagA cellular interaction via activation of the ERK signaling pathway may be a starting point in the development of gastric cancer. This study aimed to evaluate whether genes involved in ERK downstream signaling pathways activated by CagA are susceptible genetic markers for gastric cancer. Methods: In the discovery phase, a total of 580 SNPs within +/-5 kbp of 30 candidate genes were genotyped to examine an association with gastric cancer risk in the Korean Multi-center Cancer Cohort (100 incident gastric cancer case-control sets). The most significant SNPs (raw or permutated p value??0.02) identified in the discovery analysis were re-evaluated in the extension phase using unconditional logistic regression model (400 gastric cancer case-control sets). Combined analyses including pooled-and meta-analysis were conducted to summarize all the results. Results: 24 SNPs in eight genes (ERK, Dock180, C3G, Rap1, Src, CrkL, Mek and Crk) were significantly associated with gastric cancer risk in the individual SNP analyses in the discovery phase (p??0.05). In the extension analyses, ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 showed marginally significant gene-dose effects for gastric cancer. Consistently, final combined analysis presented the SNPs as significantly associated with gastric cancer risk (OR = 1.56, [95% CI: 1.19-2.06], OR = 0.61, [95% CI: 0.43-0.87], OR = 0.59, [95% CI: 0.54-0.76], respectively). Conclusions: Our findings suggest that ERK rs5999749, Dock180 rs4635002 and C3G rs7853122 are genetic determinants in gastric carcinogenesis
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