2,481 research outputs found

    Continuous quantum measurement of a Bose-Einstein condensate: a stochastic Gross-Pitaevskii equation

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    We analyze the dynamics of a Bose-Einstein condensate undergoing a continuous dispersive imaging by using a Lindblad operator formalism. Continuous strong measurements drive the condensate out of the coherent state description assumed within the Gross-Pitaevskii mean-field approach. Continuous weak measurements allow instead to replace, for timescales short enough, the exact problem with its mean-field approximation through a stochastic analogue of the Gross-Pitaevskii equation. The latter is used to show the unwinding of a dark soliton undergoing a continuous imaging.Comment: 13 pages, 10 figure

    Classification and nondegeneracy of SU(n+1)SU(n+1) Toda system with singular sources

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    We consider the following Toda system \Delta u_i + \D \sum_{j = 1}^n a_{ij}e^{u_j} = 4\pi\gamma_{i}\delta_{0} \text{in}\mathbb R^2, \int_{\mathbb R^2}e^{u_i} dx -1,, \delta_0isDiracmeasureat0,andthecoefficients is Dirac measure at 0, and the coefficients a_{ij}formthestandardtri−diagonalCartanmatrix.Inthispaper,(i)wecompletelyclassifythesolutionsandobtainthequantizationresult: form the standard tri-diagonal Cartan matrix. In this paper, (i) we completely classify the solutions and obtain the quantization result: ∑j=1naij∫R2eujdx=4π(2+Îłi+Îłn+1−i),    ∀  1≀i≀n.\sum_{j=1}^n a_{ij}\int_{\R^2}e^{u_j} dx = 4\pi (2+\gamma_i+\gamma_{n+1-i}), \;\;\forall\; 1\leq i \leq n.ThisgeneralizestheclassificationresultbyJostandWangfor This generalizes the classification result by Jost and Wang for \gamma_i=0,, \forall \;1\leq i\leq n.(ii)Weprovethatif. (ii) We prove that if \gamma_i+\gamma_{i+1}+...+\gamma_j \notin \mathbb Zforall for all 1\leq i\leq j\leq n,thenanysolution, then any solution u_i$ is \textit{radially symmetric} w.r.t. 0. (iii) We prove that the linearized equation at any solution is \textit{non-degenerate}. These are fundamental results in order to understand the bubbling behavior of the Toda system.Comment: 28 page

    The Sub-Surface Structure of a Large Sample of Active Regions

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    We employ ring-diagram analysis to study the sub-surface thermal structure of active regions. We present results using a large number of active regions over the course of Solar Cycle 23. We present both traditional inversions of ring-diagram frequency differences, with a total sample size of 264, and a statistical study using Principal Component Analysis. We confirm earlier results on smaller samples that sound speed and adiabatic index are changed below regions of strong magnetic field. We find that sound speed is decreased in the region between approximately r=0.99R_sun and r=0.995R_sun (depths of 3Mm to 7Mm), and increased in the region between r=0.97R_sun and r=0.985R_sun (depths of 11Mm to 21Mm). The adiabatic index is enhanced in the same deeper layers that sound-speed enhancement is seen. A weak decrease in adiabatic index is seen in the shallower layers in many active regions. We find that the magnitudes of these perturbations depend on the strength of the surface magnetic field, but we find a great deal of scatter in this relation, implying other factors may be relevant.Comment: 16 pages, 11 figures, accepted for publication in Solar Physic

    Kinetic Parameters Evaluation for Isoprene Mixed with Aluminum Oxide

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    AbstractWe analyzed the basic hazard characteristics for isoprene in the manufacturing process by evaluating the runaway reaction, kinetic parameters and safety parameters in this study. Experiments were carried out by calculating the thermal decomposition reactions for isoprene and mixed with aluminum oxide in non-isothermal conditions by differential scanning calorimetry (DSC). Afterwards results indicated that isoprene had a conjugated double bond of unstable structure, and therefore it was prone to produce exothermic reaction during the process of polymerization. Aluminum oxide was applied to mix with isoprene, which could increase the heat release rate. Based on the results, safety information should be provided to government and relevant industries for prevention the accident occur in relevant plants

    Stamen-less inflorescence proliferation of Bambusa edulis

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    [[abstract]]After 6 years of subculture in the presence of 0.1 mg/l thidiazuron (TDZ), a somaclonal variation of Bambusa edulis, vse had lost its capability to form stamens. The inflorescences were used to establish stamen-less inflorescence proliferation. In addition to the absence of stamens, the vse inflorescence had a longer palea and fewer trichromes on the surface than that of the wild type. In medium component studies, cytokinins were found to be essential for inflorescence proliferation, with TDZ (0.1 mg/l) and benzyladenine (1 mg/l) being the most efficient. Inflorescences were unable to proliferate in medium containing an auxin, although root formation occurred in the presence of indole-3-butyric acid and naphthaleneacetic acid (NAA). The basal MS medium supplemented with 5 mg/l NAA was the most efficient for inducing root formation, with 11% (5/45) of the inflorescences generating vegetative shoots in this medium. One of the regenerated shoots flowered after a 2 months culture. Calli formed in medium supplemented with picloram and 2,4-dichlorophenylacetic acid. None of the plant regulator treatments could restore the capability to form stamens

    In vitro flowering of green and albino Dendrocalamus latiflorus

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    [[abstract]]To propagate Dendrocalamus latiflorus, we used in vivo inflorescences to produce calli on Murashige and Skoog basal (MS) medium supplemented with 3 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D), 2 mg/l kinetin, 250 mg/l polyvinyl pyrrolidone (PVP), and 1% coconut milk. Multiple shoots were generated on MS medium supplemented with 0.1 mg/l thidiazuron (TDZ). The green plantlets were successfully transferred to soil. Multiple albino shoots also regenerated and were able to proliferate on medium containing cytokinins, especially TDZ. Albino multiple shoots rooted in medium containing α-naphthaleneacetic acid (NAA), and callus formation was observed in the presence of 2,4-D and picloram. Green and albino regenerates flowered after 8 months of subculture. The flowering ratio increased to 44% after three treatments in medium containing 1 mg/l TDZ. Morphological observations revealed that the in vitro green and albino flower organs were normal. However, pollen derived from the in vitro flowers of both the green and albino plants were sterile

    Effects of growth regulators on direct flowering of isolated ginseng buds in vitro, Plant Cell

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    [[abstract]]An in vitro method for obtaining gingseng inflorescences directly from explants of gingseng (Panax ginseng) is reported. Isolated shoot-buds of somatic embryo-derived plantlets ginseng were used as explants and incubated in B5 medium supplemented with 1 mg l?1 benzyladenine (BA) and 1 mg l?1 gibberellic acid (GA3). About 15% of the buds flowered directly without developing vegetative organs. Cytokinin was found to be the key factor for inducing these isolated buds to proliferate and flower, but both these processes also occurred when benzyladenine (BA) was replaced by thidiazuron (TDZ). The optimal concentration of TDZ for obtaining the best ratios of bud proliferation and total flowering was 0.1 mg l?1, while the highest number of vegetative shoots was obtained in medium supplemented with 1 mg l?1 GA3 and 0.1 mg l?1 TDZ. The explant elongated abnormally in the presence of 10 mg l?1 GA3. Although a low concentration (1 mg l?1) of NAA increased the bud proliferation ratio in the medium supplemented with 0.1 mg l?1 TDZ and 1 mg l?1 GA3, a high concentration (5 mg l?1) of NAA reduced the bud proliferation ratio and inhibited the flowering

    mtDNA lineage analysis of mouse L-cell lines reveals the accumulation of multiple mtDNA mutants and intermolecular recombination

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    The role of mitochondrial DNA (mtDNA) mutations and mtDNA recombination in cancer cell proliferation and developmental biology remains controversial. While analyzing the mtDNAs of several mouse L cell lines, we discovered that every cell line harbored multiple mtDNA mutants. These included four missense mutations, two frameshift mutations, and one tRNA homopolymer expansion. The LA9 cell lines lacked wild-type mtDNAs but harbored a heteroplasmic mixture of mtDNAs, each with a different combination of these variants. We isolated each of the mtDNAs in a separate cybrid cell line. This permitted determination of the linkage phase of each mtDNA and its physiological characteristics. All of the polypeptide mutations inhibited their oxidative phosphorylation (OXPHOS) complexes. However, they also increased mitochondrial reactive oxygen species (ROS) production, and the level of ROS production was proportional to the cellular proliferation rate. By comparing the mtDNA haplotypes of the different cell lines, we were able to reconstruct the mtDNA mutational history of the L-L929 cell line. This revealed that every heteroplasmic L-cell line harbored a mtDNA that had been generated by intracellular mtDNA homologous recombination. Therefore, deleterious mtDNA mutations that increase ROS production can provide a proliferative advantage to cancer or stem cells, and optimal combinations of mutant loci can be generated through recombination

    Optimal approximate fixed point results in locally convex spaces

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    Let CC be a convex subset of a locally convex space. We provide optimal approximate fixed point results for sequentially continuous maps f ⁣:C→Cˉf\colon C\to\bar{C}. First we prove that if f(C)f(C) is totally bounded, then it has an approximate fixed point net. Next, it is shown that if CC is bounded but not totally bounded, then there is a uniformly continuous map f ⁣:C→Cf\colon C\to C without approximate fixed point nets. We also exhibit an example of a sequentially continuous map defined on a compact convex set with no approximate fixed point sequence. In contrast, it is observed that every affine (not-necessarily continuous) self-mapping a bounded convex subset of a topological vector space has an approximate fixed point sequence. Moreover, it is constructed a affine sequentially continuous map from a compact convex set into itself without fixed points.Comment: 12 page
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