89 research outputs found

    Distributed Spectrum and Power Allocation for D2D-U Networks: A Scheme based on NN and Federated Learning

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    In this paper, a Device-to-Device communication on unlicensed bands (D2D-U) enabled network is studied. To improve the spectrum efficiency (SE) on the unlicensed bands and fit its distributed structure while ensuring the fairness among D2D-U links and the harmonious coexistence with WiFi networks, a distributed joint power and spectrum scheme is proposed. In particular, a parameter, named as price, is defined, which is updated at each D2D-U pair by a online trained Neural network (NN) according to the channel state and traffic load. In addition, the parameters used in the NN are updated by two ways, unsupervised self-iteration and federated learning, to guarantee the fairness and harmonious coexistence. Then, a non-convex optimization problem with respect to the spectrum and power is formulated and solved on each D2D-U link to maximize its own data rate. Numerical simulation results are demonstrated to verify the effectiveness of the proposed scheme

    Effects of Shading on Carbohydrates of Syzygium samarangense

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    Wax apple (Syzygium samarangense) is an important tropical fruit tree cultivated in Southeast Asian. It produces red pear-like shape fruits. The fruit flesh is considered high in antioxidants, phenolics, and flavonoids that have a potential to contribute to the human healthy diet, and was proved to have anti-inflammatory and antimicrobial characteristics. To allow year-round marketing of high quality wax apple fruit, growers always perform shading to inhibit new flushes so as to repress vegetative growth and promote reproductive growth. To investigate the effect of shading on carbohydrates, wax apple trees were shaded with sun shade nets under field conditions. The effects of shading on shoot growth were studied and leaf carbohydrate levels of the trees were determined. The results showed that shading inhibit the the growth of the terminal shoots and promoted bud dormancy. Shading also reduced total soluble sugar, sucrose, glucose, fructose, and starch levels of leaves. The results suggested that shading reduced carbohydrate accumulation and repressed vegetative growth

    Detection of HBV Genotypes of Tumor Tissues and Serum by A Fluorescence Polarization Assay in North-Western China's Hepatocellular Carcinoma Patients

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    <p>Abstract</p> <p>Background</p> <p>The understanding of the distribution of hepatitis B virus genotypes and the occult hepatitis B virus infection in hepatocellular carcinoma may shed light into the prevention and treatment of hepatocellular carcinoma. The purpose of the study is to investigate hepatitis B virus genotypes distribution, the high-risk genotypes and the occult infection in north-western China's hepatocellular carcinoma patients.</p> <p>Methods</p> <p>Hepatitis B virus genotypes A-D of hepatocellular carcinoma tumor tissues and serum samples in 268 north-western China hepatocellular carcinoma patients were detected by fluorescence polarization assay. The hepatitis B virus genotypes in serum and matched primary tumor tissue samples were compared. Hepatitis B surface antigen and α-fetoprotein in serum were detected. Occult hepatitis B virus infections were analyzed. The relationship between hepatitis B virus genotypes and clinicopathologic characteristics were analyzed statistically using SPSS v.10.0.</p> <p>Results</p> <p>Intrahepatic hepatitis B virus DNA was detected in 83.6% of 268 patients, whereas serum hepatitis B virus DNA was detected in 78.7%. The hepatitis B virus genotypes in serum were consistent with the results in matched tumor tissue. Intrahepatic hepatitis B virus genotype B and C were detected respectively in 11.6% and 54.5% of the patients. Mixed intrahepatic hepatitis B virus genotypes were detected in 13.4% of 268 patients. There was not mixed hepatitis B virus infection in Edmondonson grade I. The patients with mixed HBV genotypes exhibited statistically significant different Edmondson grade than the patients with single type HBV infection (p < 0.05). Hepatitis B surface antigens were positive in 77.2% of 268 patients. Hepatitis B virus genotype C was detected in 64.7% of occult infected patients. There was no significant differences of patients' ages and α-fetoprotein level in different groups of intrahepatic hepatitis B virus genotypes (p > 0.05).</p> <p>Conclusions</p> <p>Hepatitis B virus genotype C was associated closely with the development of hepatocellular carcinoma and the occult hepatitis B virus infection in patients in north-western China. There was a relatively high prevalence of mixed hepatitis B virus infection in Edmondonson grade III-IV.</p

    Non-sterile Submerged Fermentation of Fibrinolytic Enzyme by Marine Bacillus subtilis Harboring Antibacterial Activity With Starvation Strategy

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    Microbial fibrinolytic enzyme is a promising candidate for thrombolytic therapy. Non-sterile production of fibrinolytic enzyme by marine Bacillus subtilis D21-8 under submerged fermentation was realized at a mild temperature of 34°C, using a unique combination of starvation strategy and self-production of antibacterial agents. A medium composed of 18.5 g/L glucose, 6.3 g/L yeast extract, 7.9 g/L tryptone, and 5 g/L NaCl was achieved by conventional and statistical methods. Results showed efficient synthesis of fibrinolytic enzyme and antibacterial compounds required the presence of both yeast extract and tryptone in the medium. At shake-flask level, the non-sterile optimized medium resulted in higher productivity of fibrinolytic enzyme than the sterile one, with an enhanced yield of 3,129 U/mL and a production cost reduced by 24%. This is the first report dealing with non-sterile submerged fermentation of fibrinolytic enzyme, which may facilitate the development of feasible techniques for non-sterile production of raw materials for the preparation of potential drugs with low operation cost

    Activity of the Mianzishan-Qingshuiying fault in the southeast margin of the Yinchuan basin

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    Studying the tectonic activity characteristics of the Yinchuan basin is of great significance for understanding the interaction among the three major blocks of Qinghai Tibet, Ordos and Alxa. The terrain elevation difference in the Mianzishan-Zhutouling area on the southeastern margin of the Yinchuan basin is significant, and the linear trace on satellite image is obvious, indicating the development of an unknown active fault. This article conducted field geological surveys, trench excavation and stratigraphic dating along the Mianzishan-Qingshuiying line. The results showed that the linear trace along the Mianzishan-Qingshuiying line had been dominated by fault, which was developed on the southeastern margin of the Yinchuan basin with a total length of 50 km. It is divided into two segments, the Mianzishan fault and the Qingshuiying fault. The Mianzishan fault is mainly characterized by high angle normal faults, the scratches on the fault surface show a sinistral strike slip motion, heading northeast, several gullies across the fault layer display left-handed twisting characteristics. The Qingshuiying fault, on the other hand,exhibits a reverse fault trending NEE, developing steep slope landforms. The fault has displaced sedimentary strata deposited at (23.65 ± 1.17) ka BP and (33.16 ± 1.82) ka BP, indicating its latest activity was postdated by Late Pleistocene. The discovery of this fault indicates that the boundary of the northwestern Ordos block is a complex zone associated with a wide structural deformation zone. This zone is not strictly controlled by the boundary faults of Yinchuan basin, but expanded to interior of the Ordos block, which may be related to the continuous northeast pushing and expansion of the Qinghai Tibet Plateau

    Spring Flood Forecasting Based on the WRF-TSRM Mode

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    The snowmelt process is becoming more complex in the context of global warming, and the current existing studies are not effective in using the short-term prediction model to drive the distributed hydrological model to predict snowmelt floods. In this study, we selected the Juntanghu Watershed in Hutubi County of China on the north slope of the Tianshan Mountains as the study area with which to verify the snowmelt flood prediction accuracy of the coupling model. The weather research and forecasting (WRF) model was used to drive a double-layer distributed snowmelt runoff model called the Tianshan Snowmelt Runoff Model (TSRM), which is based on multi-year field snowmelt observations. Moreover, the data from NASA’s moderate resolution imaging spectroradiometer (MODIS) was employed to validate the snow water equivalent during the snow-melting period. Results show that, based on the analysis of the flow lines in 2009 and 2010, the WRF-driven TSRM has an overall 80% of qualification ratios (QRs), with determination coefficients of 0.85 and 0.82 for the two years, respectively, which demonstrates the high accuracy of the model. However, due to the influence of the ablation of frozen soils, the forecasted flood peak is overestimated. This problem can be solved by an improvement to the modeled frozen soil layers. The conclusion reached in this study suggests that the WRF-driven TSRM can be used to forecast short-term snowmelt floods on the north slope of the Tianshan Mountains, which can effectively improve the local capacity for the forecasting and early warning of snowmelt floods

    Polarization-Reconfigurable Circularly Polarized Planar Antenna Using Switchable Polarizer

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    A novel polarization-reconfigurable planar antenna is presented. The antenna consists of an electronically reconfigurable polarizer integrated with a printed slot. By changing the states of the PIN diodes on the polarizer, the linearly polarized (LP) waves radiated by the slot can be converted to either right-hand circularly polarized (RHCP) or left-hand circularly polarized (LHCP) waves. The polarizer contains 16 unit cells arranged as a 4 × 4 array. The antenna radiates RHCP waves if the PIN diodes on the top side of the polarizer are switched ON, while LHCP waves are radiated if the PIN diodes of the bottom side of the polarizer are switched ON instead. The physical mechanisms of the antenna are discussed and the parametric study is carried out by full-wave simulations. To verify the concept, one prototype at 2.5 GHz is designed, fabricated and measured. Good agreement between the measured and simulated results is obtained. The antenna achieves a gain ? 8.5 dBic in both RHCP and LHCP with aperture efficiency of 70%. Advantages of the proposed design include electronicallyreconfigurable polarizations for RHCP or LHCP, low profile, low cost, high isolation between the DC bias circuit and RF signals, high power handling capability and easy extension to large-scale arrays without increasing the complexity of the DC bias circuit. To the best knowledge of the authors, this is the first report of an electronically polarization-reconfigurable circularly polarized antenna with a single-substrate polarizer

    Logistic regression analysis of risk factors for pediatric burns: a case–control study in underdeveloped minority areas in China

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    BackgroundPediatric burns are common, especially in underdeveloped countries, and these can physically affect the children involved and have an impact on their mental health. The aim of the present study was to assess the effect of pediatric burns in underdeveloped minority areas of China.MethodsCase information from 192 children was collected from outpatient and inpatient clinics using a survey questionnaire. These included 90 pediatric burn cases and 102 controls who were children without burns. A stepwise logistic regression analysis was used to determine the risk factors for pediatric burns in order to establish a model. The goodness-of-fit for the model was assessed using the Hosmer and Lemeshow test as well as receiver operating characteristic and internal calibration curves. A nomogram was then used to analyze the contribution of each influencing factor to the pediatric burns model.ResultsSeven variables, including gender, age, ethnic minority, the household register, mother’s employment status, mother’s education and number of children, were analyzed for both groups of children. Of these, age, ethnic minority, mother’s employment status and number of children in a household were found to be related to the occurrence of pediatric burns using univariate logistic regression analysis (p &lt; 0.05). After a collinearity diagnosis, a multivariate logistic regression analysis of variables with tolerances of &gt;0.2 and variance inflation factor &lt;5 showed that age was a protective factor for pediatric burns [odds ratio (OR) = 0.725; 95% confidence interval (CI): 0.665–0.801]. Compared with single-child parents, those with two children were at greater risk of pediatric burns (OR = 0.389; 95% CI: 0.158–0.959). The ethnic minority of the child and the mother’s employment status were also risk factors (OR = 6.793; 95% CI: 2.203–20.946 and OR = 2.266; 95% CI: 1.025–5.012, respectively). Evaluation of the model used was found to be stable. A nomogram showed that the contribution in the children burns model was age &gt; mother’s employment status &gt; number of children &gt; ethnic minority.ConclusionsThis study showed that there are several risk factors strongly correlated to pediatric burns, including age, ethnic minority, the number of children in a household and mother’s employment status. Government officials should direct their preventive approach to tackling the problem of pediatric burns by promoting awareness of these findings

    Uncertainty-inspired Open Set Learning for Retinal Anomaly Identification

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    Failure to recognize samples from the classes unseen during training is a major limit of artificial intelligence (AI) in real-world implementation of retinal anomaly classification. To resolve this obstacle, we propose an uncertainty-inspired open-set (UIOS) model which was trained with fundus images of 9 common retinal conditions. Besides the probability of each category, UIOS also calculates an uncertainty score to express its confidence. Our UIOS model with thresholding strategy achieved an F1 score of 99.55%, 97.01% and 91.91% for the internal testing set, external testing set and non-typical testing set, respectively, compared to the F1 score of 92.20%, 80.69% and 64.74% by the standard AI model. Furthermore, UIOS correctly predicted high uncertainty scores, which prompted the need for a manual check, in the datasets of rare retinal diseases, low-quality fundus images, and non-fundus images. This work provides a robust method for real-world screening of retinal anomalies
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