6,503 research outputs found

    Angular momentum and energy structure of the coherent state of a 2D isotropic harmonic oscillator

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    The angular momentum structure and energy structure of the coherent state of a 2D isotropic harmonic oscillator were investigated. Calculations showed that the average values of angular momentum and energy (except the zero point energy) of this nonspreading 2D wave packet are identical to those of the corresponding classical oscillator moving along a circular or an elliptic orbit

    Isolation, sequence identification and tissue expression profile of a novel ribokinase gene (RBKS) from Chinese Banna mini-pig inbred line (BMI)

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    The complete expressed sequence tag (CDS) sequence of Banna mini-pig inbred line (BMI) ribokinase gene (RBKS) was amplified using the reverse transcription-polymerase chain reaction (RT-PCR) based on the conserved sequence information of the cattle or other mammals and known highly homologous swine ESTs. This novel gene was then deposited into NCBI database and assigned to accession number JF944892. Sequence analysis revealed that the BMI RBKS encodes a protein of 323 amino acids that has high homology with the ribokinase proteins of seven species: cattle (99%), horse (99%), orangutan (99%), human (89%), monkey (89%), rat (88%) and mouse (80%). The phylogenetic tree analysis revealed that the BMI RBKS gene has a closer genetic relationship with the RBKS genes of bovine and horse than with those of orangutan, human, monkey, rat and mouse. Analysis by RT-PCR showed that BMI RBKS gene was over-expressed in ovary and lung, moderately expressed in spleen, nerve fiber, large intestine and diencephalon, weakly expressed in heart, skin, muscle, small intestine, midbrain, kidney and fat, while almost silent in other five tissues. Four microRNA target sites were predicted in the CDS of BMI RBKS mRNA for further study of this gene in the future. The 3D structure of the RBKS by homology modeling was similar to that of human ribokinase (2fv7). Our experiment will establish a foundation for further insight into this swine gene.Key words: Banna mini-pig inbred line (BMI), pig, ribokinase gene (RBKS), tissue expression analysis, homology modelin

    High temperature deformation constitutive model of GGG70L duction iron

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    In order to accurately describe the high temperature deformation behavior of GGG70L ductile iron, the thermal simulation experiments with deformation rate of 0,01~10 s-1 were carried out at 800~1 100 °C by Gleeble-1500D thermal simulation machine. The deformation behavior of GGG70L ductile iron was studied. The temperature compensated strain rate Zener-Hollomon parameter was introduced, and the constitutive model of GGG70L ductile iron was established based on the strain compensated Arrhenius model. The results show that the theoretical value of peak stress calculated by the constitutive model is in good agreement with the experimental results, and the correlation is 97,8 %, which can accurately describe the high temperature deformation behavior of GGG70L ductile iro

    Highly indistinguishable and strongly entangled photons from symmetric GaAs quantum dots

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    The development of scalable sources of non-classical light is fundamental to unlocking thetechnological potential of quantum photonics. Semiconductor quantum dots are emerging asnear-optimal sources of indistinguishable single photons. However, their performance assources of entangled-photon pairs are still modest compared to parametric down converters.Photons emitted from conventional Stranski–Krastanov InGaAs quantum dots have shownnon-optimal levels of entanglement and indistinguishability. For quantum networks, bothcriteria must be met simultaneously. Here, we show that this is possible with a system thathas received limited attention so far: GaAs quantum dots. They can emit triggered polar-ization-entangled photons with high purity (g(2)(0) = 0.002±0.002), high indistinguish-ability (0.93±0.07 for 2 ns pulse separation) and high entanglement fidelity(0.94±0.01). Our results show that GaAs might be the material of choice for quantum-dotentanglement sources in future quantum technologie

    Signals of El Niño Modoki in the tropical tropopause layer and stratosphere

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    The effects of El Niño Modoki events on the tropical tropopause layer (TTL) and on the stratosphere were investigated using European Center for Medium Range Weather Forecasting (ECMWF) reanalysis data, oceanic El Niño indices, and general climate model outputs. El Niño Modoki events tend to depress convective activities in the western and eastern Pacific but enhance convective activities in the central and northern Pacific. Consequently, during El Niño Modoki events, negative water vapor anomalies occur in the western and eastern Pacific upper troposphere, whereas there are positive anomalies in the central and northern Pacific upper troposphere. The spatial patterns of the outgoing longwave radiation (OLR) and upper tropospheric water vapor anomalies exhibit a tripolar form. The empirical orthogonal function (EOF) analysis of the OLR and upper tropospheric water vapor anomalies reveals that canonical El Niño events are associated with the leading mode of the EOF, while El Niño Modoki events correspond to the second mode. The composite analysis based on ERA-interim data indicate that El Niño Modoki events have a reverse effect on middle-high latitudes stratosphere, as compared with the effect of typical El Niño events, i.e., the northern polar vortex is stronger and colder but the southern polar vortex is weaker and warmer during El Niño Modoki events. According to the simulation' results, we found that the reverse effect on the middle-high latitudes stratosphere is resulted from a complicated interaction between quasi-biennial oscillation (QBO) signal of east phase and El Niño Modoki signal. This interaction is not a simply linear overlay of QBO signal and El Niño Modoki signal in the stratosphere, it is El Niño Modoki that leads to different tropospheric zonal wind anomalies with QBO forcing from that caused by typical El Niño, thus, the planetary wave propagation from troposphere to the stratosphere during El Niño Modoki events is different from that during canonical El Niño events. However, when QBO is in its west phase, El Niño Modoki events have the same effect on middle-high latitudes stratosphere as the typical El Niño events. Our simulations also suggest that canonical El Niño and El Niño Modoki activities actually have the same influence on the middle-high latitudes stratosphere when in the absence of QBO forcing

    Intelectin contributes to allergen-induced IL-25, IL-33, and TSLP expression and type 2 response in asthma and atopic dermatitis.

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    The epithelial and epidermal innate cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) have pivotal roles in the initiation of allergic inflammation in asthma and atopic dermatitis (AD). However, the mechanism by which the expression of these innate cytokines is regulated remains unclear. Intelectin (ITLN) is expressed in airway epithelial cells and promotes allergic airway inflammation. We hypothesized that ITLN is required for allergen-induced IL-25, IL-33, and TSLP expression. In two asthma models, Itln knockdown reduced allergen-induced increases in Il-25, Il-33, and Tslp and development of type 2 response, eosinophilic inflammation, mucus overproduction, and airway hyperresponsiveness. Itln knockdown also inhibited house dust mite (HDM)-induced early upregulation of Il-25, Il-33, and Tslp in a model solely inducing airway sensitization. Using human airway epithelial cells, we demonstrated that HDM-induced increases in ITLN led to phosphorylation of epidermal growth factor receptor and extracellular-signal regulated kinase, which were required for induction of IL-25, IL-33, and TSLP expression. In two AD models, Itln knockdown suppressed expression of Il-33, Tslp, and Th2 cytokines and eosinophilic inflammation. In humans, ITLN1 expression was significantly increased in asthmatic airways and in lesional skin of AD. We conclude that ITLN contributes to allergen-induced Il-25, Il-33, and Tslp expression in asthma and AD

    Ages and Masses of 0.64 million Red Giant Branch stars from the LAMOST Galactic Spectroscopic Survey

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    We present a catalog of stellar age and mass estimates for a sample of 640\,986 red giant branch (RGB) stars of the Galactic disk from the LAMOST Galactic Spectroscopic Survey (DR4). The RGB stars are distinguished from the red clump stars utilizing period spacing derived from the spectra with a machine learning method based on kernel principal component analysis (KPCA). Cross-validation suggests our method is capable of distinguishing RC from RGB stars with only 2 per cent contamination rate for stars with signal-to-noise ratio (SNR) higher than 50. The age and mass of these RGB stars are determined from their LAMOST spectra with KPCA method by taking the LAMOST - KeplerKepler giant stars having asteroseismic parameters and the LAMOST-TGAS sub-giant stars based on isochrones as training sets. Examinations suggest that the age and mass estimates of our RGB sample stars with SNR >> 30 have a median error of 30 per cent and 10 per cent, respectively. Stellar ages are found to exhibit positive vertical and negative radial gradients across the disk, and the age structure of the disk is strongly flared across the whole disk of 6<R<136<R<13\,kpc. The data set demonstrates good correlations among stellar age, [Fe/H] and [α\alpha/Fe]. There are two separate sequences in the [Fe/H] -- [α\alpha/Fe] plane: a high--α\alpha sequence with stars older than \sim\,8\,Gyr and a low--α\alpha sequence composed of stars with ages covering the whole range of possible ages of stars. We also examine relations between age and kinematic parameters derived from the Gaia DR2 parallax and proper motions. Both the median value and dispersion of the orbital eccentricity are found to increase with age. The vertical angular momentum is found to fairly smoothly decrease with age from 2 to 12\,Gyr, with a rate of about -50\,kpc\,km\,s1^{-1}\,Gyr1^{-1}. A full table of the catalog is public available online.Comment: 16 pages, 22 figures,accepted by MNRA

    A method to separate temperature and precipitation signals encoded in tree-ring widths for the western Tien Shan Mountains, northwest China

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    Separating temperature and precipitation signals encoded in tree rings is a complicated issue. Here, we present a separation method by combining two tree-ring width chronologies of Schrenk's spruce (Picea schrenkiana) from the upper and lower timberlines in the western Tien Shan Mountains, northwest China. Correlation analyses show that both chronologies correlate positively with precipitation. However, temperature correlates positively with the chronology from the upper timberline, while negatively with the chronology from the lower timberline. This suggests that the two chronologies contain similar precipitation information but opposite temperature signals. In light of this, we calculated the average and difference of the two chronologies, and found that each of them has a much stronger correlation with precipitation or temperature alone. Finally, we reconstructed local precipitation and temperature variations over the past 201 years by using the average and difference of the two chronologies. The two reconstructions do not have a significant correlation, but they have significant positive and negative relationships on the high- and low-frequency band, respectively.postprin
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