1,468 research outputs found

    Radio Sources in the NCP Region Observed with the 21 Centimeter Array

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    We present a catalog of 624 radio sources detected around the North Celestial Pole (NCP) with the 21 Centimeter Array (21CMA), a radio interferometer dedicated to the statistical measurement of the epoch of reionization (EoR). The data are taken from a 12 h observation made on 2013 April 13, with a frequency coverage from 75 to 175 MHz and an angular resolution of ~ 4 arcmin. The catalog includes flux densities at eight sub-bands across the 21CMA bandwidth and provides the in-band spectral indices for the detected sources. To reduce the complexity of interferometric imaging from the so-called "w" term and ionospheric effects, the present analysis are restricted to the east-west baselines within 1500 m only. The 624 radio sources are found within 5 degrees around the NCP down to ~ 0.1 Jy. Our source counts are compared, and also exhibit a good agreement, with deep low-frequency observations made recently with the GMRT and MWA. In particular, for fainter radio sources below ~ 1 Jy, we find a flattening trend of source counts towards lower frequencies. While the thermal noise (~0.4 mJy) is well controlled to below the confusion limit, the dynamical range (~10^4) and sensitivity of current 21CMA imaging is largely limited by calibration and deconvolution errors, especially the grating lobes of very bright sources, such as 3C061.1, in the NCP field which result from the regular spacings of the 21CMA. We note that particular attention should be paid to the extended sources, and their modeling and removals may constitute a large technical challenge for current EoR experiments. Our analysis may serve as a useful guide to design of next generation low-frequency interferometers like the Square Kilometre Array.Comment: 16 pages, 21 figures, 7 tables, 1 machine readable table, accepted for publication in Ap

    Routing Optimization of Intelligent Vehicle in Automated Warehouse

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    Routing optimization is a key technology in the intelligent warehouse logistics. In order to get an optimal route for warehouse intelligent vehicle, routing optimization in complex global dynamic environment is studied. A new evolutionary ant colony algorithm based on RFID and knowledge-refinement is proposed. The new algorithm gets environmental information timely through the RFID technology and updates the environment map at the same time. It adopts elite ant kept, fallback, and pheromones limitation adjustment strategy. The current optimal route in population space is optimized based on experiential knowledge. The experimental results show that the new algorithm has higher convergence speed and can jump out the U-type or V-type obstacle traps easily. It can also find the global optimal route or approximate optimal one with higher probability in the complex dynamic environment. The new algorithm is proved feasible and effective by simulation results

    Enhancing CT Image synthesis from multi-modal MRI data based on a multi-task neural network framework

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    Image segmentation, real-value prediction, and cross-modal translation are critical challenges in medical imaging. In this study, we propose a versatile multi-task neural network framework, based on an enhanced Transformer U-Net architecture, capable of simultaneously, selectively, and adaptively addressing these medical image tasks. Validation is performed on a public repository of human brain MR and CT images. We decompose the traditional problem of synthesizing CT images into distinct subtasks, which include skull segmentation, Hounsfield unit (HU) value prediction, and image sequential reconstruction. To enhance the framework's versatility in handling multi-modal data, we expand the model with multiple image channels. Comparisons between synthesized CT images derived from T1-weighted and T2-Flair images were conducted, evaluating the model's capability to integrate multi-modal information from both morphological and pixel value perspectives.Comment: 4 pages, 3 figures, 2 table

    Role of FIP200 in cardiac and liver development and its regulation of TNFα and TSC–mTOR signaling pathways

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    Focal adhesion kinase family interacting protein of 200 kD (FIP200) has been shown to regulate diverse cellular functions such as cell size, proliferation, and migration in vitro. However, the function of FIP200 in vivo has not been investigated. We show that targeted deletion of FIP200 in the mouse led to embryonic death at mid/late gestation associated with heart failure and liver degeneration. We found that FIP200 knockout (KO) embryos show reduced S6 kinase activation and cell size as a result of increased tuberous sclerosis complex function. Furthermore, FIP200 KO embryos exhibited significant apoptosis in heart and liver. Consistent with this, FIP200 KO mouse embryo fibroblasts and liver cells showed increased apoptosis and reduced c-Jun N-terminal kinase phosphorylation in response to tumor necrosis factor (TNF) α stimulation, which might be mediated by FIP200 interaction with apoptosis signal–regulating kinase 1 (ASK1) and TNF receptor–associated factor 2 (TRAF2), regulation of TRAF2–ASK1 interaction, and ASK1 phosphorylation. Together, our results reveal that FIP200 functions as a regulatory node to couple two important signaling pathways to regulate cell growth and survival during mouse embryogenesis

    High hepatitis B virus load is associated with hepatocellular carcinomas development in Chinese chronic hepatitis B patients: a case control study

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    <p>Abstract</p> <p>Background</p> <p>Persistent hepatitis B virus (HBV) infection is a risk factor for hepatocellular carcinoma (HCC) development. This study aimed to clarify whether the high HBV DNA level is associated with HCC development by comparing HBV DNA levels between HBV infected patients with and without HCC.</p> <p>Results</p> <p>There were 78 male and 12 female patients in each group and there was no statistical difference between these two group patients' average ages. The HBV DNA level in the HCC patients was 4.73 ± 1.71 Log<sub>10 </sub>IU/ml while 3.90 ± 2.01 Log<sub>10 </sub>IU/ml in non-HCC patients (<it>P </it>< 0.01). The HBeAg positive rate was 42.2% (38/90) in the HCC group while 13.3% (12/90) in the non-HCC group (<it>P </it>< 0.001). Compared with patients with HBV DNA level of < 3 Log<sub>10 </sub>IU/ml, the patients with level of 3 to < 4, 4 to < 5, 5 to < 6, or ≥ 6 Log<sub>10 </sub>IU/ml had the odds ratio for HCC of 1.380 (95% CI, 0.544-3.499), 3.671 (95% CI, 1.363-9.886), 5.303 (95% CI, 1.847-15.277) or 3.030 (95% CI, 1.143-8.036), respectively.</p> <p>Conclusions</p> <p>HBV-related HCC patients had higher HBV DNA level than non-HCC counterparts. Our findings imply that active HBV replication is associated with the HCC development.</p

    USING ARTHROSCOPY TO OBSERVE THE EFFECT OF LIVER-SOFTENING MEDICINE ON KNEE OSTEOARTHRITIS

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    Background: Arthroscopy was used to observe the clinical effect of liver-softening medicine for treating knee osteoarthritis (OA). Materials and Methods: Forty knee OA patients with cartilage classifications of Outerbridge grade II, III, or II plus III determined via arthroscopy were randomly assigned to a treatment of liver-softening medicine plus glucosamine or a control treatment of glucosamine alone. Clinical observation and determination of the comprehensive effect score were performed at 60, 120, and 180 days. A second arthroscopy was performed at 180 days. Results: Signs and symptoms significantly improved at different time points in the treatment group. The effects in the treatment group were better than those in the control group. When analyzing the cartilage during the second arthroscopy, no further degeneration was observed. Conclusions: After arthroscopic debridement, the treatment of knee OA with liver-softening medicine in conjunction with glucosamine is a feasible and effective solution

    Central gas entropy excess as a direct evidence for AGN feedback in galaxy groups and clusters

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    By analyzing Chandra X-ray data of a sample of 21 galaxy groups and 19 galaxy clusters, we find that in 31 sample systems there exists a significant central (R<10h711R^{<}_{\sim} 10h_{71}^{-1} kpc) gas entropy excess (ΔK0\Delta K_{0}), which corresponds to 0.10.5\simeq 0.1-0.5 keV per gas particle, beyond the power-law model that best fits the radial entropy profile of outer regions. We also find a distinct correlation between the central entropy excess ΔK0\Delta K_{0} and KK-band luminosity LKL_{K} of the central dominating galaxies (CDGs), which is scaled as ΔK0LK1.6±0.4\Delta K_{0} \propto L_{K}^{1.6\pm0.4}, where LKL_{K} is tightly associated with the mass of the supermassive black hole hosted in the CDG. In fact, if an effective mass-to-energy conversion-efficiency of 0.02 is assumed for the accretion process, the cumulative AGN feedback EfeedbackAGNηMBHc2E^{\rm AGN}_{\rm feedback} \simeq \eta M_{\rm BH}c^{2} yields an extra heating of 0.517.0\simeq 0.5-17.0 keV per particle, which is sufficient to explain the central entropy excess. In most cases the AGN contribution can compensate the radiative loss of the X-ray gas within the cooling radius (0.0022.2\simeq 0.002-2.2 keV per particle), and apparently exceeds the energy required to deviate the scaling relations from the self-similar predictions (0.21.0\simeq 0.2-1.0 keV per particle). In contrast to the AGN feedback, the extra heating provided by supernova explosions accounts for 0.010.08\simeq 0.01-0.08 keV per particle in groups and is almost negligible in clusters. Therefore, the observed correlation between ΔK0\Delta K_{0} and LKL_{K} can be considered as a direct evidence for AGN feedback in galaxy groups and clusters.Comment: 14 pages, 3 figures, accepted by RA
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