111 research outputs found

    Multiscale Technicolor and bsγb \to s \gamma

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    Correction to the bsγb\rightarrow s\gamma branching ratio in the multiscale walking technicolor model (MWTCM) is examined. For the original MWTCM, the correction is too large to explain the recent CLEO data. We show that if topcolor is further introduced, the branching ratio in the topcolor assisted MWTCM can be in agreement with the CLEO data for a certain range of the parameters.Comment: 11 pages, Latex, no macros, 3 figures, hard copy is available upon request. to appear in Z. Phys.

    Generalized Completed Local Binary Patterns for Time-Efficient Steel Surface Defect Classification

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    © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted ncomponent of this work in other works.Efficient defect classification is one of the most important preconditions to achieve online quality inspection for hot-rolled strip steels. It is extremely challenging owing to various defect appearances, large intraclass variation, ambiguous interclass distance, and unstable gray values. In this paper, a generalized completed local binary patterns (GCLBP) framework is proposed. Two variants of improved completed local binary patterns (ICLBP) and improved completed noise-invariant local-structure patterns (ICNLP) under the GCLBP framework are developed for steel surface defect classification. Different from conventional local binary patterns variants, descriptive information hidden in nonuniform patterns is innovatively excavated for the better defect representation. This paper focuses on the following aspects. First, a lightweight searching algorithm is established for exploiting the dominant nonuniform patterns (DNUPs). Second, a hybrid pattern code mapping mechanism is proposed to encode all the uniform patterns and DNUPs. Third, feature extraction is carried out under the GCLBP framework. Finally, histogram matching is efficiently accomplished by simple nearest-neighbor classifier. The classification accuracy and time efficiency are verified on a widely recognized texture database (Outex) and a real-world steel surface defect database [Northeastern University (NEU)]. The experimental results promise that the proposed method can be widely applied in online automatic optical inspection instruments for hot-rolled strip steel.Peer reviewe

    Discrimination experiment of sound distance perception for a real source in near-field

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    International audienceThe ability of distance perception is quite important for our daily life. For the backward region where the vision cannot cover, listeners perceive objects only via binaural hearing, and the distance perception for a backward sound source is very important. It helps listeners to perceive an approaching sound source and avoid dangerous object especially when the sound source is in the rear. In the free field, the main acoustic distance perception cues for a nearby sound source include intensity variation with distance, binaural cues, dynamic cues, spectrum change and direct-to-reverberant energy ratio (Pavel Zahorik, 2005). Theoretically, all the above mentioned cues can be simulated via virtual auditory display (VAD), and realized by using a real sound source in an anechoic chamber. In comparison, the results based on a real sound source measurement should be more accurate. Previous researches have proved that the sound pressure has a giant influence on the ability of distance discrimination in both near field and far field when source is in front of head (Daniel H. Ashmead, 1990). However, few researches attempt to examine the binaural effect alone in distance perception. The theory was based on a fact that both the sound intensities and spectrums of a nearby sound will be different in two ears due to the head shadow, and these differences will change with distance when the sound source is lateral (PAUL D. COLEMAN, 1963). To verify the impact of binaural effect to distance discrimination, we conducted an experiment to exam the backward sound distance perception thresholds when the sound is presented from different azimuths in the horizontal plane. We used an automatic test system controlled by a computer in an anechoic room, eight listeners participated in the test. A loudness balanced band noise was used as test signals to remove the influence of sound level, and the signal was presented in 75 dBA. One signal was presented in the reference distance (50cm or 100cm), while the other one was presented in a closer distance, and sequence is random. The subjects need to do 2IFC (choose the closer one) between the signals presented in two different distances, and no feedback was given to subjects.The discrimination thresholds of two reference distances (0.5m and 1m) and five source azimuth (0°, 45°, 90°, 135°, 180°, right half plane of head) were examined in the experiment. The result show that subjects distance discrimination thresholds are lower when the sound source is on the side of head (about 20%) compared with front and back (above 30%), distinguishing two signals become quite difficult for participants when signals are presented in azimuth 0° and 180°. Moreover, this phenomenon is more prominent in 50cm compared with 100cm, while the effect of head shadow is more significant in 50cm. The results obtained in this study are consistent with previous studies and reveal that the binaural effect indeed contributes to distance discrimination process of human in a degree. This work is supported by the National Natural Science Foundation of China (Grant No. 11574090) and the Natural Science Foundation of Guangdong Province (Grant No. 2018B030311025)

    The eruption characteristics of the Tarim flood basalt

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    Integration of field investigation, regional stratigraphic comparison, remote sensing and image interpretation allow us to divide the Tarim Permian flood basalt province into three eruptive cycles listed by decreasing age; Kupukuziman flood basalt (KP), Felsic pyroclastic rocks (FP), Kaipaizileike flood basalt (KZ). KP features flood basalt and tuff; in the outcrop in Keping and Yingmaili areas, it can be differentiated into two units containing three thick layers of basaltic lava flows. These three layers decrease to one layer of basaltic lava flow in the Halahatang area; however, felsic pyroclastic rocks and lava layer thicknesses increase in the Halahatang area. FP in the outcrop in Keping area consists of ash fall tuff, ignimbrite, resedimented pyroclastic rocks, and the tuff layer interbedded with the normal elastic rocks section from top to bottom. This section is comparable to the tuff layer in the Yingmaili and Halahatang area, thus reveals one layer of lava flow covering an extensive area clue to a unit of the eruption of the FP. KZ mainly features flood basalt in its Kaipaizileike section, identifications of 4 eruptive units, 8 layers of flood basalt, and I layer of andesitic basalt were made. Traces of elastic rocks were found between eruption units, but no FP interlayers were found. This characteristic is different from Yingmaili and Halahatang volcanic se.quences, but similar to the flood basalt in Tazhong area. The differentiation between these three volcanic cycles reveals that Tarim flood basalt underwent a "flood basalt-felsic pyroclastic rocks-flood basalt " transformation, and is similar to Afro-Arabian large igneous province; thus, a comparative study between these two regions is merited

    Effect of a 180 mg ticagrelor loading dose on myocardial necrosis in patients undergoing elective percutaneous coronary intervention: A preliminary study

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    Background: To examine whether a loading dose of ticagrelor on top of clopidogrel reduced postpercutaneous coronary intervention (PCI) myonecrosis. Methods: Seventy seven coronary artery disease patients received a loading dose of 300 mg clopidogrel pre-PCI and were divided into three groups: group TT (n = 36): a loading dose of 180 mg ticagrelor pre-PCI, followed by ticagrelor 90 mg twice daily commencing one day post-PCI; group CT (n = 26): a maintenance dose of ticagrelor 90 mg twice daily; group CC (n = 15): clopidogrel 75 mg daily post- PCI. High sensitivity cardiac troponin T (hs-cTnT) and creatine kinase-MB (CK-MB) were measured pre-PCI and 0 h, 2 h or 24 h post-PCI. Platelet aggregation was measured in a separate cohort of 54 coronary artery disease patients (35 diabetic and 19 non-diabetic patients). Results: There were no significant differences in hs-cTnT and CK-MB concentration among the three groups. In group TT, diabetic patients had significant higher Δhs-cTnT2h–0h than non-diabetic patients. In the second cohort, although baseline platelet aggregation was higher in diabetic than non-diabetic patients, platelet aggregation was comparable between diabetic and non-diabetic patients at 0 and 2 h post-PCI. Conclusions: This study indicates that a loading dose of ticagrelor does not significantly reduce post- PCI myonecrosis. Diabetes is associated with more post-PCI myonecrosis. A loading dose of ticagrelor effectively reduces platelet aggregation in diabetic patients.

    The eruption characteristics of the Tarim flood basalt

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    Integration of field investigation, regional stratigraphic comparison, remote sensing and image interpretation allow us to divide the Tarim Permian flood basalt province into three eruptive cycles listed by decreasing age; Kupukuziman flood basalt (KP), Felsic pyroclastic rocks (FP), Kaipaizileike flood basalt (KZ). KP features flood basalt and tuff; in the outcrop in Keping and Yingmaili areas, it can be differentiated into two units containing three thick layers of basaltic lava flows. These three layers decrease to one layer of basaltic lava flow in the Halahatang area; however, felsic pyroclastic rocks and lava layer thicknesses increase in the Halahatang area. FP in the outcrop in Keping area consists of ash fall tuff, ignimbrite, resedimented pyroclastic rocks, and the tuff layer interbedded with the normal elastic rocks section from top to bottom. This section is comparable to the tuff layer in the Yingmaili and Halahatang area, thus reveals one layer of lava flow covering an extensive area clue to a unit of the eruption of the FP. KZ mainly features flood basalt in its Kaipaizileike section, identifications of 4 eruptive units, 8 layers of flood basalt, and I layer of andesitic basalt were made. Traces of elastic rocks were found between eruption units, but no FP interlayers were found. This characteristic is different from Yingmaili and Halahatang volcanic se.quences, but similar to the flood basalt in Tazhong area. The differentiation between these three volcanic cycles reveals that Tarim flood basalt underwent a "flood basalt-felsic pyroclastic rocks-flood basalt " transformation, and is similar to Afro-Arabian large igneous province; thus, a comparative study between these two regions is merited

    DCPoint: global-local dual contrast for self-supervised representation learning of 3D point clouds

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    In recent years, 3D vision has gained increasing prominence in practical applications such as autonomous driving and robotics. However, the scarcity of large labeled point cloud datasets continues to be a bottleneck for deep networks. Self-supervised representation learning (SRL) has emerged as an effective approach to alleviate this issue by pre-training general feature encoders without requiring human annotations. Existing contrastive SRL methods for 3D point clouds have predominantly concentrated on object representations from a global or point perspective. They overlook essential local geometry information, thereby constraining the generalizability of pre-trained models. To address these challenges, we propose a local contrast module as an intermediate level between the scene and point levels. It is then integrated with a global contrast module to form a dual contrast method known as DCPoint. The local contrast module operates on point-wise representations of objects and designs contrastive pairs based on the spatial information of point clouds. It effectively addresses the challenges posed by the sparsity and irregularity of point clouds and imperfect partition issues. The point-wise local contrast module aims to enhance the internal connections between the components within the point cloud, while the global contrast module introduces semantic information about individual instances. Experimental results demonstrate the effectiveness of DCPoint across various downstream tasks on synthetic and real-world datasets. It consistently outperforms previously reported SRL methods and the randomly initialized counterparts. Additionally, the proposed local contrast module can enhance the performances of other SRL methods

    High level soluble expression, one-step purification and characterization of HIV-1 p24 protein

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    <p>Abstract</p> <p>Background</p> <p>P24 protein is the major core protein of HIV virus particle and has been suggested as a specific target for antiviral strategies. Recombinant p24 protein with natural antigenic activity would be useful for various studies, such as diagnostic reagents and multi-component HIV vaccine development. The aim of this study was to express and purify the p24 protein in soluble form in <it>E.coli</it>.</p> <p>Results</p> <p>According to the sequence of the p24 gene, a pair of primers was designed, and the target sequence of 700 bp was amplified using PCR. The PCR product was cloned into pQE30 vector, generating the recombinant plasmid pQE30-p24. SDS-PAGE analysis showed that the His-tagged recombinant p24 protein was highly expressed in soluble form after induction in <it>E. coli </it>strain BL21. The recombinant protein was purified by nickel affinity chromatography and used to react with HIV infected sera. The results showed that the recombinant p24 protein could specifically react with the HIV infected sera. To study the immunogenicity of this soluble recombinant p24 protein, it was used to immunize mice for the preparation of polyclonal antibody. Subsequent ELISA and Western-Blot analysis demonstrated that the p24 protein had proper immunogenicity in inducing mice to produce HIV p24 specific antibodies.</p> <p>Conclusion</p> <p>In this work, we report the high level soluble expression of HIV-1 p24 protein in <it>E. coli</it>. This soluble recombinant p24 protein specifically react with HIV infected sera and elicit HIV p24 specific antibodies in mice, indicating this soluble recombinant p24 protein could be a promising reagent for HIV diagnosis.</p

    Ionic cluster effect in suppression on superconductivity in Ni- and Co-doped YBCO systems

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    We adopted the x-ray diffraction, oxygen contents, positron annihilation technology as well as simulation methods to investigate systemically YBa₂Cu₃–x(Ni,Co)xO₇–δ (x = 0–0.5). The simulated results show that ions distribute in dispersive form in little doped concentration. As doped concentration increases, ions combine into clusters in the crystal lattice. The calculated results and oxygen contents, together with the impure phases and the local electron density ne, show the ionic cluster effect, which not only causes the local electron density to reach the saturation, but also suppress the superconductivity significantly
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