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在现有大规模分布式环境中，大数据应用的性能与计算效率仍有较大的提升空间。然而，在大规模环境中进行性能分析与优化需要大量领域专家。针对大数据应用中的性能优化问题，提出了一个通用的低效查询语句检测与优化流程，总结了4类显著影响大数据应用性能的低效行为，并针对每一类低效行为，提出了具体的优化策略。最后，通过实验评估验证了提出的优化方案在实际大规模集群中的有效性。

Copyright of Journal of Railway Science & Engineering is the property of Journal of Railway Science & Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of China Condiment is the property of China Condiment and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Shanghai Jiao Tong University (1006-2467) is the property of Journal of Shanghai Jiao Tong University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Big Data Research (2096-0271) is the property of Beijing Xintong Media Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Clinical Healthcare is the property of Chinese Journal of Clinical Healthcare and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Functional Materials / Gongneng Cailiao is the property of Chongqing Functional Materials Periodical Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to explore an effective water injection development method for tight sandstone reservoirs, six flat models with length, width, and height of 40 cm, 40 cm, and 5 cm were made using Chang-8 layer outcrop cores from the Ordos Basin. The effects of cyclic water injection, asynchronous injection-production in the same well of horizontal wells, and asynchronous injection and production of different wells in horizontal wells on oil and water distribution, pressure distribution, and final recovery degree were studied through plate experiments. The experimental results show that the initial water injection flow line of the periodic water injection plate advances evenly towards the production end, forming a fan-shaped water drive front, and forming a channeling flow at the fracture. The longer the water injection half cycle is, the more obvious the fracture water channeling is. Properly shortening the water injection half cycle is conducive to improving the recovery degree. The injection water of asynchronous injection and production experiment in different horizontal wells flows from the injection fracture to the adjacent production fracture of the same well and the opposite production fracture at the same time, mainly between the relative fractures. The asynchronous fracture of the horizontal well is opposite the injection and production test, and the remaining oil is concentrated in a strip near the edge of the production well and in the middle of the plate. The asynchronous fracture of the horizontal well is staggered, and the remaining oil in the injection and production test is concentrated in a broken line near the edge of the production well and in the middle of the plate. Both of them have a wide range of water drive. The staggered injection and production fractures effectively avoid premature water flooding and improve the recovery degree. [ABSTRACT FROM AUTHOR]

Cellulose aerogels were obtained by cellulose homogeneous solution using cotton linter as raw material and ionic liquid as dissolution system・ When 1 -ally 1-3-methylimidazolium chloride salt was used as the solvent system, the concentration of cotton linter was 2% and the polymerization degree was 1 500, the specific surface area of cellulose aerogel obtained by vacuum freeze・drying using tert-butanol as replacement solvent could reach 288 ・ 731 0 m²/g, and the pore volume was 2. 252 8 cm³/g, the pore size was 30. 94 nni. And the effects of ionic liquid type, drying method, cellulose polymerization degree, cellulose concentration and solvent replacement type on the microstructure of cellulose aerogels were investigated by BET, SEM, XRD, FTIR, TG/DTG analysis. [ABSTRACT FROM AUTHOR]

Objective To investigate the relationships between serum microRNA-223（miR-223), interleukin-6 (IL-6) and brain damage in children with complex febrile seizures (CFS) . Methods Totally 124 children with CFS (CFS group) were divided into the brain injury group of 39 cases and the non-brain injury group of 85 cases according to whether they had brain injury or not； meanwhile，46 healthy children at the same period (control group) were selected. Real-time fluorescence quantitative polymerase chain reaction and enzyme-linked immunosorbent assay were used to detect serum miR-223 and IL-6 expression. Spearman's correlation was used to analyze the correlation of serum miR-223 and IL6 levels in the serum of CFS patients, multifactorial Logistic regression was used to analyze the factors affecting brain injury in children with CFS, and the predictive value of serum miR-223 and IL-6 levels in children with CFS was analyzed by using receiver operating characteristic (ROC) curve. Results Compared with the control group, serum miR-223 level decreased and IL-6 level increased in the CFS group (both P<0. 05) . Serum miR-223 was negatively correlated with IL-6 level in children with CFS (r＝－0. 800，P<0. 05) . The incidence of brain injury in 124 children with CFS was 31. 45% (39/124) . Generalized convulsions, the number of convulsive seizures ≥2, duration of convulsive seizures ≥5 min, and elevated IL-6 were independent risk factors for brain injury in children with CFS, and elevated miR-223 was an independent protective factor (all P<0. 05) . The area under the curve of serum miR-223 combined with IL-6 level in prediction of brain injury of children with CFS was 0. 899, which was greater than that (0. 803，0. 780) of serum miR-223 and IL-6 levels alone (both P<0. 05) . Conclusions Decreased serum miR-223 level and increased IL-6 level are closely associated with brain injury in children with CFS, and the combination of serum miR-223 and IL-6 levels is of high value in predicting brain injury in children with CFS. [ABSTRACT FROM AUTHOR]

Copyright of University Chemistry is the property of Peking University, College of Chemistry & Molecular Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science Technology & Engineering is the property of Chinese Society of Technology Economics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Biotechnology Bulletin is the property of Biotechnology Bulletin Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: The eastern Liaoning Province represents the eldest hydrothermal uranium ore cluster area in China. Two ore types are classified, including independent uranium mineralization and uranium mineralization associated with Precambrian sedimentary-metamorphic iron deposits. The ore-forming age of the former type has been well constrained at ~1.85Ga, whereas the age of the latter type remains uncertain. Iron deposit-associated uranium mineralization developed in the Wengquangou B-Mg-Fe deposit, the Gaojiagou Fe deposit, and the Gongchangling Fe deposit. Geochronological studies on uraninite of the Wengquangou deposit yielded variable ages ranging from 2.0 to 1.8Ga, with some ages even older than the depositional ages of the hosting Liaohe Group (2.05 to 1.93Ga). This inconsistency suggests that some uraninite grains used for dating are detrital in origin. The lack of reliable age constraints on the iron deposit-associated uranium mineralization has raised questions about its origin. It remains unknown whether the iron deposit-associated uranium mineralization resulted from the same hydrothermal process and formed at the same tectonic setting when compared with the independent uranium mineralization. OBJECTIVES: To determine the metallogenic age and verify the accuracy of the age in uranium. METHODS: The instrument JXA-iHP200F was used for analysis, and the age was calculated according to Ranchin’s empirical formula. The analytical conditions were 20kV acceleration voltage, 50nA beam current, and 5μm beam spot size. A further LA-ICP-MS U-Pb dating method was used to verify the EPMA chemical ages of the uraninite, using a 193nm GeoLasPro and Agilent 7900 ICP-MS with a laser spot size of 16μm. RESULTS: The calculated age of the Wengquangou deposit ranges from 1899 to 1324Ma, but it is mainly concentrated from 1899 to 1741Ma. Two peaks at 1859Ma and 1784Ma are constrained by an age frequency distribution histogram. This result is younger than the deposition age of the Liaohe Group. The age of the Gongchangling deposit ranges from 1858Ma to 1715Ma, with two peaks at 1865Ma and 1743Ma constrained by an age frequency distribution histogram. In the Wengquangou deposit, the position for uraninite LA-ICP-MS U-Pb dating corresponds to EPMA analytical points. The weighted mean ages are grouped into 1840±16Ma (MSWD=2.0) and 1787±8Ma (MSWD=0.95), which are consistent with the results obtained by EPMA. The loss of Pb can result in disruption of U-Th-Pb isotope system and thus affect the calculated ages. The loss of Pb can be probed because it is generally considered to be positively correlated with Si, Ca and Fe contents. The SiO2+CaO+FeO contents of most measuring spots of uraninite of the two deposits is less than 1%, and show no correlation with Pb contents, indicating that the loss of Pb is negligible. CONCLUSIONS: The uranium mineralization associated with iron deposits has been constrained at ~1.85Ga and then experienced hydrothermal superposition at ~1.78Ga. The age results indicate that both the independent and iron ore-associated uranium mineralization in the eastern Liaoning Province was formed at ~1.85Ga, linking to a Proterozoic post-orogenic extensional environment in the eastern North China craton. The ore-forming fluids of different deposits of iron associated uranium deposits are all alkaline and oxidated but vary in fluid composition and temperature. This study highlights combined application of EPMA and LA-ICP-MS dating methods on uraninite, realizing the complementary advantages of spatial resolution and dating precision. [ABSTRACT FROM AUTHOR]

Copyright of Biotechnology Bulletin is the property of Biotechnology Bulletin Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to explore effective water injection methods for shale reservoirs, 12 long cores with a length of nearly 100 cm and a diameter of nearly 10 cm were made from the Chang 7 shale outcrop in the Ordos Basin. Through laboratory experiments, the production conditions of continuous water injection, pulse water injection, unstable water injection, periodic water injection, horizontal well water injection and conventional well water injection were studied. The results show that under the same recovery degree, the water content of continuous displacement is the highest, and the water content of cyclic water injection method with interval injection and interval recovery is the lowest. The cyclic water injection method of inter injection and inter extraction is the highest at 35. 24%, and the continuous water injection method is the lowest at 28. 35% . Under the same rotation, the higher the injection pressure, the higher the degree of recovery through water injection, with a maximum value of 5. 08% . Under a certain throughput pressure, the first round of extraction has the highest degree. As the number of rounds increases, the single round of extraction significantly decreases, with a decrease of 82. 61% in the third round. The effect of horizontal well water injection stimulation is better than that of conventional well water injection stimulation. A higher water injection pressure is beneficial for achieving a higher degree of recovery. The large amplitude of pressure change is beneficial for activating the crude oil in small pores and improving crude oil recovery efficiency. Due to the lack of continuous energy replenishment during water injection huff and puff, the recovery rate is about 30% lower than that of cyclic water injection. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of China Medical University is the property of Journal of China Medical University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Preventive Veterinary Medicine / Zhongguo Yufang Shouyi Xuebao is the property of Chinese Journal of Preventive Veterinary Medicine Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Power Engineering Technology is the property of Editorial Department of Electric Power Engineering Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Mycosystema is the property of Mycosystema Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective To investigate the expression of signal transducer and activator of transcription 3 (STAT3) in endometrial cancer tissues, and to analyze its relationship with common pathological parameters. Methods The endometrial cancer tissues collected from 45 patients were selected as the observation group, and the para-cancer endometrial tissues sampled from 40 patients were selected as the control group. Immuno-histochemical staining was used to detect the expression of STAT3. The relationship between STAT3 expression and pathological parameters was analyzed. Results The positive rate of STAT3 expression in endometrial cancer tissues was significantly higher than that in paracancer endometrial tissues(P＜0.001). The positive rate of STAT3 expression in endometrial carcinoma tissues with histological grade G2-3 and myometrium invasion＞1/2 was significantly higher than that in endometrial cancer tissues with histological grade G1 and myometrium invasion≤1/2(P＜0.05). Conclusions The expression of STAT3 is significantly increased in endometrial cancer tissues, and is related to the histological grade and myometrium invasion of endometrial cancer, which potentially support the targeted therapy and prognosis assessment of endometrial cancer. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Yulin is one of the prefecture-level cities bordering Mu Us Sandy Land and Loess Plateau in Shaanxi Province, China. Among them, the Mu Us Sandy Land is one of the most typical ecologically fragile areas. The soil environment in Yulin City has presented the profound impact after remarkable remediation and utilization in recent years. Soil organic matter (SOM) can be an important indicator of soil fertility and productivity. The trend of SOM can also greatly contribute to the decision-making on the stability and security of soil ecosystem under different natural conditions and anthropogenic influence. It is a high demand to monitor the SOM dynamic changes from the large-scale space and long time series. Taking the conspicuous sandy land in Yulin City as the research area, the purpose of this study is to determine the characteristics of land use changes from 1990 to 2020. A systematic investigation was also performed on the variations in the SOM content under different land types that transformed from the sandy land, in order to clarify the effects of different remediation and utilization on the SOM in the sandy land. The dominant sandy land was selected to calculate the dynamic attitude of land use for the transformation characteristics of land use. Three machine learnings (decision tree, random forest, and XGBoost) were used to evaluate the factors related to the natural conditions and land use change characteristics of sandy land. The fitting accuracy was then obtained, according to each waveband of multispectral remote sensing images and related spectral indices. Finally, the XGBoost was selected to invert the SOM content. A systematic analysis was made on the SOM content and spatial distribution characteristics under different land types. After that, a semi-variance function was used to reveal the spatial variability. The average SOM content was calculated to clarify the influence of anthropogenic factors and natural environment on the desert SOM. The results show that more than half of the sandy land was remediated and utilized from 1990 to 2020, indicating the fastest transformation. Specifically, the sandy grassland was the most important land transformation, whereas, the fastest increase was found in the construction land area. The better inversion was also obtained to estimate the SOM content with the inversion error within 13% than before, according to the multispectral remote sensing using XGBoost machine learning. The average SOM of arable land and water area reached nearly 0.8% of land use types. The SOM of all land use types decreased significantly, with the average SOM of 0.51% in 2020. A strong spatial autoregulation of SOM was depended mainly on the natural environmental factors, such as temperature, precipitation, and topography. Initially, the human activities posed a positive impact. But, a negative impact was led to the decline in the SOM content and the land degradation, as the intensity of sand use increased. Some recommendations were given to strengthen the restoration and improvement of degraded forest and grass. The finding can provide the theoretical and practical implications for the sandy land remediation, particularly for the protection of the soil environmental safety of Yulin sandy land. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Journal of Changzhou University (Natural Science Edition) / Changzhou Daxue Xuebao (Ziran Kexue Ban) is the property of Editorial Department of Journal of Changzhou University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of China Medical University is the property of Journal of China Medical University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of West China Journal of Stomatology is the property of Sichuan University, West China College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)