217 research outputs found

    Bose-Einstein condensation in strong-coupling quark color superconductor near flavor SU(3) limit

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    Near the flavor SU(3) limit, we propose an analytical description for color-flavor-locked-type Bardeen-Cooper-Schrieffer (BCS) phase in the Nambu Jona-Lasinio (NJL) model. The diquark behaviors in light-flavor and strange-flavor-involved channels and Bose-Einstein condensation (BEC) of bound diquark states are studied. When the attractive interaction between quarks is strong enough, a BCS-BEC crossover is predicted in the environment with color-flavor-locked pairing pattern. The resulting Bose-Einstein condensed phase is found to be an intergrade phase before the emergence of the previous-predicted BEC phase in two-flavor quark superconductor.Comment: 15 pages, 5 figures; 2nd versio

    The influence of the boundary resistivity on the proximity effect

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    We apply the theory of Takahashi and Tachiki in order to explain theoretically the dependence of the upper critical magnetic field of a S/N multilayer on the temperature. This problem has been already investigated in the literature, but with a use of an unphysical scaling parameter for the coherence length. We show explicitely that, in order to describe the data, such an unphysical parameter is unnecessary if one takes into account the boundary resisitivity of the S/N interface. We obtain a very good agreement with the experiments for the multilayer systems Nb/Cu and V/Ag, with various layer thicknesses.Comment: 12 pages, 5 figure

    Transverse Λ0\Lambda^0 polarization in inclusive quasi-real photoproduction at the current fragmentation

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    It is shown that the recent HERMES data on the transverse Λ0\Lambda^0 polarization in the inclusive quasi-real photoproduction at xF>0x_F>0 can be accommodated by the strange quark scattering model. Relations with the quark recombination approach are discussed.Comment: 5 pages, 3 figures, accepted by Eur. Phys. J.

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

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    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps−1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter

    Getting the strain under control: Trans-Varestraint tests for hot cracking susceptibility

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    A new method for conducting Trans-Varestraint tests for assessing hot cracking susceptibility is proposed. Experiments were carried out, to validate the new method, with an industrial scale rig using tungsten inert gas welding. The hot cracking susceptibility of API-5L X65 and EN3B steel was compared. The results indicated that, by using the new method, the strain applied to the welding bead and consequently to the solidification front was controlled in a repeatable and reliable way. The results also indicated that EN3B has a maximum crack length (a parameter in the test) higher than X65 and it is reached at lower augmented strain thus demonstrating it is more susceptible to hot cracking, while also indicating that there is a capability of predicting the initiation position of hot cracks during welding. By using the method proposed, the capability of setting standardized test procedures for Trans-Varestraint tests is improved. It is recommended that future tests for assessing hot cracking susceptibility should employ the proposed method in order for the results to be comparable and to also study the effect of strain rate in hot cracking of materials

    Morphological segmentation analysis and texture-based support vector machines classification on mice liver fibrosis microscopic images

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    Background To reduce the intensity of the work of doctors, pre-classification work needs to be issued. In this paper, a novel and related liver microscopic image classification analysis method is proposed. Objective For quantitative analysis, segmentation is carried out to extract the quantitative information of special organisms in the image for further diagnosis, lesion localization, learning and treating anatomical abnormalities and computer-guided surgery. Methods in the current work, entropy based features of microscopic fibrosis mice’ liver images were analyzed using fuzzy c-cluster, k-means and watershed algorithms based on distance transformations and gradient. A morphological segmentation based on a local threshold was deployed to determine the fibrosis areas of images. Results the segmented target region using the proposed method achieved high effective microscopy fibrosis images segmenting of mice liver in terms of the running time, dice ratio and precision. The image classification experiments were conducted using Gray Level Co-occurrence Matrix (GLCM). The best classification model derived from the established characteristics was GLCM which performed the highest accuracy of classification using a developed Support Vector Machine (SVM). The training model using 11 features was found to be as accurate when only trained by 8 GLCMs. Conclusion The research illustrated the proposed method is a new feasible research approach for microscopy mice liver image segmentation and classification using intelligent image analysis techniques. It is also reported that the average computational time of the proposed approach was only 2.335 seconds, which outperformed other segmentation algorithms with 0.8125 dice ratio and 0.5253 precision

    Recent Asian origin of chytrid fungi causing global amphibian declines

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    Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of the most devastating panzootic to date, caused by the fungus Batrachochytrium dendrobatidis, a proximate driver of global amphibian declines. We traced the source of B. dendrobatidis to the Korean peninsula, where one lineage, BdASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for B. dendrobatidis biodiversity and the original source of these lineages that now parasitize amphibians worldwide

    The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2

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    We present and analyze observations of polarized dust emission at 850 ÎŒm toward the central 1 7 1 pc hub-filament structure of Monoceros R2 (Mon R2). The data are obtained with SCUBA-2/POL-2 on the James Clerk Maxwell Telescope (JCMT) as part of the B-fields in Star-forming Region Observations survey. The orientations of the magnetic field follow the spiral structure of Mon R2, which are well described by an axisymmetric magnetic field model. We estimate the turbulent component of the magnetic field using the angle difference between our observations and the best-fit model of the underlying large-scale mean magnetic field. This estimate is used to calculate the magnetic field strength using the Davis–Chandrasekhar–Fermi method, for which we also obtain the distribution of volume density and velocity dispersion using a column density map derived from Herschel data and the C18O (J = 3 - 2) data taken with HARP on the JCMT, respectively. We make maps of magnetic field strengths and mass-to-flux ratios, finding that magnetic field strengths vary from 0.02 to 3.64 mG with a mean value of 1.0 \ub1 0.06 mG, and the mean critical mass-to-flux ratio is 0.47 \ub1 0.02. Additionally, the mean Alfv\ue9n Mach number is 0.35 \ub1 0.01. This suggests that, in Mon R2, the magnetic fields provide resistance against large-scale gravitational collapse, and the magnetic pressure exceeds the turbulent pressure. We also investigate the properties of each filament in Mon R2. Most of the filaments are aligned along the magnetic field direction and are magnetically subcritical

    Measurement of the CP-Violating Asymmetry Amplitude sin2ÎČ\beta

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    We present results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 88 million Y(4S) --> B Bbar decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We study events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0bar from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay-time distributions in such events. We measure sin2beta = 0.741 +/- 0.067 (stat) +/- 0.033 (syst) and |lambda| = 0.948 +/- 0.051 (stat) +/- 0.017 (syst). The magnitude of lambda is consistent with unity, in agreement with the Standard Model expectation of no direct CP violation in these modes
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