869 research outputs found

    Riesz basis generation, eigenvalues distribution, and exponential stability for a euler-bernoulli beam with joint feedback control

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    Using an abstract result on Riesz basis generation for discrete operators in general Hilbert spaces, we show, in this article, that the generalized eigenfunctions of an Euler-Bernoulli beam equation ith oint linear feedback control form a Riesz basis for the tate space. The spectrum-determined growth condition is hence obtained. Meanwhile, the exponential stability as well as the asymptotic expansion of eigenvalues are also readily obtained by a straightforward computation

    Grooming of Dynamic Traffic in WDM Star and Tree Networks Using Genetic Algorithm

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    The advances in WDM technology lead to the great interest in traffic grooming problems. As traffic often changes from time to time, the problem of grooming dynamic traffic is of great practical value. In this paper, we discuss dynamic grooming of traffic in star and tree networks. A genetic algorithm (GA) based approach is proposed to support arbitrary dynamic traffic patterns, which minimizes the number of ADM's and wavelengths. To evaluate the algorithm, tighter bounds are derived. Computer simulation results show that our algorithm is efficient in reducing both the numbers of ADM's and wavelengths in tree and star networks.Comment: 15 page

    Electronic structure in underdoped cuprates due to the emergence of a pseudogap

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    The phenomenological Green's function developed in the works of Yang, Rice and Zhang has been very successful in understanding many of the anomalous superconducting properties of the deeply underdoped cuprates. It is based on considerations of the resonating valence bond spin liquid approximation and is designed to describe the underdoped regime of the cuprates. Here we emphasize the region of doping, xx, just below the quantum critical point at which the pseudogap develops. In addition to Luttinger hole pockets centered around the nodal direction, there are electron pockets near the antinodes which are connected to the hole pockets by gapped bridging contours. We determine the contours of nearest approach as would be measured in angular resolved photoemission experiments and emphasize signatures of the Fermi surface reconstruction from the large Fermi contour of Fermi liquid theory (which contains 1+x1+x hole states) to the Luttinger pocket (which contains xx hole states). We find that the quasiparticle effective mass renormalization increases strongly towards the edge of the Luttinger pockets beyond which it diverges.Comment: 11 pages, 9 figure

    The Coupling and Competition of Crystallization and Phase Separation, Correlating Thermodynamics and Kinetics In OPV Morphology and Performances

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    The active layer morphology transition of organic photovoltaics under non-equilibrium conditions are of vital importance in determining the device power conversion efficiency and stability; however, a general and unified picture on this issue has not been well addressed. Using combined in situ and ex situ morphology characterizations, morphological parameters relating to kinetics and thermodynamics of morphology evolution are extracted and studied in model systems under thermal annealing. The coupling and competition of crystallization and demixing are found to be critical in morphology evolution, phase purification and interfacial orientation. A unified model summarizing different phase diagrams and all possible kinetic routes is proposed. The current observations address the fundamental issues underlying the formation of the complex multi-length scale morphology in bulk heterojunction blends and provide useful morphology optimization guidelines for processing devices with higher efficiency and stability

    Danggui Buxue Tang – A Chinese herbal decoction activates the phosphorylations of extracellular signal-regulated kinase and estrogen receptor α in cultured MCF-7 cells

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    AbstractDanggui Buxue Tang (DBT), a Chinese herbal decoction used to treat ailments in women, contains Radix Astragali (Huangqi; RA) and Radix Angelicae Sinensis (Danggui; RAS). The weight ratio of RA to RAS used in DBT must be 5:1 as stipulated as early as AD 1247; however, DBT’s mechanism of action has never been described. Here, the estrogenic effects of DBT were investigated by determining the phosphorylations of estrogen receptor α (ERα) and extracellular signal-regulated kinase 1/2 (Erk1/2) in cultured MCF-7 cells. The application of DBT triggered the phosphorylation of ERα and Erk1/2 in a time-dependent manner. In contrast to the effect of estrogen, DBT triggered ERα phosphorylation at both S118 and S167. This DBT-specific phosphorylation was not triggered by an extract of one of the individual herbs, or by mixing the extracts of RA and RAS. DBT-induced downstream signals are described here. These signals suggest the uniqueness of this Chinese herbal decoction that requires a well-defined formulation

    Interacting entropy-corrected new agegraphic dark energy in Brans-Dicke cosmology

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    Motivated by a recent work of one of us [1], we extend it by using quantum (or entropy) corrected new agegraphic dark energy in the Brans-Dicke cosmology. The correction terms are motivated from the loop quantum gravity which is one of the competitive theories of quantum gravity. Taking the non-flat background spacetime along with the conformal age of the universe as the length scale, we derive the dynamical equation of state of dark energy and the deceleration parameter. An important consequence of this study is the phantom divide scenario with entropy-corrected new agegraphic dark energy. Moreover, we assume a system of dark matter, radiation and dark energy, while the later interacts only with dark matter. We obtain some essential expressions related with dark energy dynamics. The cosmic coincidence problem is also resolved in our model.Comment: 16 pages, no figure, accepted for publication in Gen. Relativ. Gra

    Generation of genomic-integration-free human induced pluripotent stem cells and the derived cardiomyocytes of X-linked dilated cardiomyopathy from DMD gene mutation

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    We derived an integration-free induced pluripotent stem cell (iPSC) line from the peripheral blood mononuclear cells (PBMCs) of a 23-year-old male patient. This patient carries a 5′ splice site point mutation in intron 1 (c.31+1G > A) of the dystrophin gene, a mutation associated with X-linked dilated cardiomyopathy (XLDCM). Sendai virus was used to reprogram the PBMCs and deliver OCT3/4, SOX2, c-MYC, and KLF4 factors. The iPSC line (HKUi002-A) generated preserved the mutation, expressed common pluripotency markers, differentiated into three germ layers in vivo, and exhibited a normal karyotype. Further differentiation into cardiomyocytes enables the study of the disease mechanisms of XLDCM

    New γ -ray transitions observed in Ne 19 with implications for the O 15 (α,γ) Ne 19 reaction rate

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    The O15(α,γ)Ne19 reaction is responsible for breakout from the hot CNO cycle in type I x-ray bursts. Understanding the properties of resonances between Ex=4 and 5 MeV in Ne19 is crucial in the calculation of this reaction rate. The spins and parities of these states are well known, with the exception of the 4.14- and 4.20-MeV states, which have adopted spin-parities of 9/2- and 7/2-, respectively. γ-ray transitions from these states were studied using triton-γ-γ coincidences from the F19(He3,tγ)Ne19 reaction measured with the GODDESS (Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies) at Argonne National Laboratory. The observed transitions from the 4.14- and 4.20-MeV states provide strong evidence that the Jπ values are actually 7/2- and 9/2-, respectively. These assignments are consistent with the values in the F19 mirror nucleus and in contrast to previously accepted assignments

    γ -ray spectroscopy of astrophysically important states in Ca 39

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    Background: Nova explosions synthesize elements up to A≃40, and discrepancies exist between calculated and observed abundances of Ar and Ca created in the explosion. The K38(p,γ)Ca39 reaction rate has been shown to be influential on these isotopic abundances at the endpoint of nova nucleosynthesis. The energies of the three most important resonances, corresponding to Jπ=5/2+ excited states in the Ca39 nucleus above the proton separation threshold, are uncertain and one has been measured with conflicting values [Er=679(2) versus Er=701(2) keV] in previous experiments. Purpose: Reducing the uncertainties on the resonance energies would allow for a better understanding of the reaction rate. To improve these uncertainties, we searched for γ rays from the depopulation of the corresponding excited states in Ca39. Methods: We report a new measurement of these resonance energies via the observation of previously unobserved γ-ray transitions. These transitions were observed by studying the Ca40(3He,αγ)Ca39 reaction with Gammasphere ORRUBA Dual Detectors for Experimental Structure Studies (GODDESS). The updated resonance energies were then used to calculate the K38(p,γ)Ca39 reaction rate and assess its uncertainties. Results: In total, 23 new transitions were found, including three γ-ray transitions corresponding to the three Jπ=5/2+ states of astrophysical interest at energies of 6156.2(16), 6268.8(22), and 6470.8(19) keV. These correspond to resonance energies in the K38(p,γ)Ca39 reaction of 386(2), 498(2), and 701(2) keV. Conclusions: Updated K38(p,γ)Ca39 reaction rate calculations show a reduced upper limit at nova temperatures. However, the lower-than-previously-measured energy of the 498-keV resonance and uncertainty in its resonance strength increases the upper limit of the rate close to previous estimates at 0.4 GK
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