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daily variation of radon gas and its short-lived progeny concentration near ground level and estimation of aerosol residence time

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Chinese Physics B 2016年第5期25卷 111-118页

作者： M Mohery A M Abdallah A Ali S S Baz Physics Department Faculty of Science University of Jeddah Physics Department Faculty of Science Sohag University Astronomy Department Faculty of Science King Abdulaziz University Astronomy Department Faculty of Science Cairo University Physics Department Girls Faculty of Science King Abdulaziz University

Atmospheric concentrations of radon（^（222）Rn） gas and its short-lived progenies^（218）Po,^（214）Pb, and^（214）Po were continuously monitored every four hours at the ground level in Jeddah city, Kingdom of Saudi Arabia. The measurements were performed three times every week, starting from November 2014 to October 2015. A method of electrostatic precipitation of positively charged^（218）Po and ^（214）Po by a positive voltage was applied for determining^（222）Rn gas concentration. The short-lived^（222）Rn progeny concentration was determined by using a filter holder connected with the alpha-spectrometric technique. The meteorological parameters（relative air humidity, air temperature, and wind speed） were determined during the measurements of^（222）Rn and its progeny concentrations.^（222）Rn gas as well as its short-lived progeny concentration display a daily and seasonal variation with high values in the night and early morning hours as compared to low values at noon and in the afternoon. The observed monthly atmospheric concentrations showed a seasonal trend with the highest values in the autumn/winter season and the lowest values in the spring/summer season. Moreover, and in parallel with alphaspectrometric measurements, a single filter-holder was used to collect air samples. The deposited activities of^（214）Pb and the long-lived^（222）Rn daughter ^（210）Pb on the filter were measured with the gamma spectrometric technique. The measured activity concentrations of^（214）Pb by both techniques were found to be relatively equal largely. The highest mean seasonally activity concentrations of ^（210）Pb were observed in the autumn/winter season while the lowest mean were observed in the spring/summer season. The mean residence time（MRT） of aerosol particles in the atmospheric air could be estimated from the activity ratios of ^（210）Pb/^（214）Pb.

关键词： daily variation radon progeny concentration meteorological variables

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Monitoring models for base flow effect and daily variation of dam seepage elements considering time lag effect

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Water Science and Engineering 2018年第4期11卷 344-354页

作者： Shao-wei Wang Ying-li Xu Chong-shi Gu Teng-fei Bao School of Environmental and Safety Engineering Changzhou University State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University

Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend and short-term fluctuation of the dam seepage behavior, two monitoring models were developed, one for the base flow effect and one for daily variation of dam seepage elements. In the first model, to avoid the influence of the time lag effect on the evaluation of seepage variation with the time effect component of seepage elements, the base values of the seepage element and the reservoir water level were extracted using the wavelet multi-resolution analysis method, and the time effect component was separated by the established base flow effect monitoring model. For the development of the daily variation monitoring model for dam seepage elements, all the previous factors, of which the measured time series prior to the dam seepage element monitoring time may have certain influence on the monitored results, were considered. Those factors that were positively correlated with the analyzed seepage element were initially considered to be the support vector machine(SVM) model input factors, and then the SVM kernel function-based sensitivity analysis was performed to optimize the input factor set and establish the optimized daily variation SVM model. The efficiency and rationality of the two models were verified by case studies of the water level of two piezometric tubes buried under the slope of a concrete gravity *** analysis of the optimized SVM model shows that the influences of the daily variation of the upstream reservoir water level and rainfall on the daily variation of piezometric tube water level are processes subject to normal distribution.

关键词： Dam seepage monitoring model Time lag effect Support vector machine(SVM) Sensitivity analysis Base flow daily variation Piezometric tube water level

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Circadian clock and temporal meal pattern

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Medical Review 2023年第1期3卷 85-101页

作者： Xin Li Zheng Sun Department of Medicine-Endocrinology Diabetesand MetabolismBaylor College of MedicineHoustonTXUSA Department of Molecular and Cellular Biology Baylor College of MedicineHoustonTXUSA Department of Medicine-Endocrinology Diabetesand MetabolismBaylor College of Medicine1 Baylor Plz MS185HoustonTX 77030USA Department of Molecular and Cellular Biology Baylor College of MedicineHoustonTX 77030USA

The central circadian clock in the brain controls the time-of-the-day variations in acute meal responses,with a low glycemic response but a high satiety/thermo-genic response to meals consumed at waking compared to other time ***,studies show that consuming a significant proportion of calories,particularly carbohydrates,in breakfast is beneficial for the chronic management of obesity and its associated metabolic syndrome,compared to consuming identical meals at ***,breakfast skipping or/and late dinner can have unfavorable metabolic *** remains controversial how meal frequency affects metabolic *** contrast,irregular meals,especially irregular breakfasts,show consistent adverse metabolic ***-restricted feeding(TRF),with all calories consumed within less than 12-h per day,can improve metabolism and extend lifespan.A major component of TRF in humans is caloric restriction,which contributes significantly to the beneficial effects of TRF in *** comparison,TRF effects in rodents can be independent of caloric restriction and show day/night phase *** could alleviate metabolic abnormalities due to circadian disruption,but its effects appear independent of the circadian clock in *** neuroendocrine mechanisms underlying clock-mediated metabolic regulation will shed light on the metabolic effects of temporal meal patterns.

关键词： cardiometabolic circadian rhythm daily variation diabetes meal response suprachiasmatic nuclei

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Statistical characteristics of the surface ducts over the South China Sea from GPS radiosonde data

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Acta Oceanologica Sinica 2015年第11期34卷 63-70页

作者： CHENG Yinhe ZHOU Shengqi WANG Dongxiao LU Yuanzheng YAO Jinglong Guangdong Province Key Laboratory of Coastal Ocean variation and Disaster Prediction College of Ocean and Meteorology Guangdong Ocean University State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences

Based on the global position system （GPS） radiosonde data near the sea surface, the surface duct characteristics over the South China Sea （SCS） were statistically analyzed. The annual surface duct occurrence over the SCS was about 64%. Of the observed surface ducts, duct heights mainly distributed between 18 and 42 m, with M slopes in the range of -0.3 to -0.2 M units/m. Those ducts accounted for about 80% of the ducting cases. For the total profiles, the duct occurrences in a day changed slowly and were more than 60% in all times. The surface ducts formed more easily in the daytime than in the nighttime and most of the duct height were at bellow about 32 m. Additionally, The seasonal variation of the SCS ducts appeared to be evident, except that the mean duct thickness was almost constant, about 33 m for all seasons. The highest occurrence was about 71% in the autumn, followed by in the summer, spring and winter. In spring, their top-height existed more often at a height of more than 48 m. Their mean duct strength became stronger trend from spring to winter, with the M-slope in the range between -0.26 and -0.18 M units/m. Those results agreed well with other studies, provided considering the data resolution. The statistical analysis was reliable and gave the duct estimation for the SCS. Such duct climatology not only has important implications for communication systems and the reliability of the radar observation, but also can provide useful information to improve the accuracy of the meteorological radar measurements.

关键词： GPS radiosonde surface ducts distribution daily variation seasonal variation

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OBSERVATIONAL STUDY OF MERIDIONAL variation OF UV-B RADIATION DURING VOYAGES TO THE ARCTIC AND ANTARCTIC REGIONS

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Acta meteorologica Sinica 2002年第2期16卷 253-260页

作者：陆龙骅卞林根逯昌贵程彦杰 Chinese Academy of Meteorological Sciences Beijing 100081

Based on 1999-2000 observations made by the first Arctic and sixteenth Antactic scientific voyages,a study is undertaken about the meridional surface UV-B (B band ultraviolet rays) variations in 75°N-70°*** is mitigated as a function of latitudes and marked by lower radiation averaged over the Northern Hemisphere (NH) than over the Southern Hemisphere (SH),with its daily course basically similar to that of total *** polar summer noon hours (local time) and where ice albedo is maximum,the strongest UV-B irradiance on the surface perpendicular to sun's beams as found at equatorial latitudes is measured *** the areas near Zhongshan Station the increase of surface UV-B radiation shows a close relation to the decrease of ozone in the higher atmosphere but it has a less intimate relation with its concentration at ground.

关键词： polar region UV-B radiation meridional variation daily variation ozone

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Diurnal variation of Photosynthetic Physiological Characteristics of Kadsura coccinea(Lem.)***

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Agricultural Biotechnology 2021年第4期10卷 48-50,54页

作者： Zongyou CHEN Shengfeng CHAI Xiaoxue QI Yujing Wei Huafei CEN Guangxi Institute of Botany Chinese Academy of SciencesGuangxi Zhuang Autonomous RegionGuilin 541006China

[Objectives]This study was conducted to investigate the diurnal variations of photosynthetic and physiological characteristics in 3-year-old Kadsura coccinea(Lem.)*** plants.[Methods]A Li-6400 portable photosynthetic system was used to study the diurnal variations of the photosynthetic physiological characteristics of ***.[Results]The diurnal variation of the net photosynthetic rate(Pn)of *** leaves showed a"double peak"curve,and there was a lunch break at *** maximum value of Pn[4.51 mmol/(m^(2)·s)]appeared at 10:00,and the daily average Pn was 3.98 mol/(m^(2)·s);and the stepwise regression analysis showed that photosynthetically active radiation(PAR)and stomatal conductance(Gs)were the main factors affecting *** partial correlation analysis and path analysis showed that the order of effects on Pn was Gs>PAR.[Conclusions]This study provides a reference for further research on the development and utilization of ***.

关键词： Kadsura coccinea(Lem.)A.C.Smith Net photosynthetic rate daily variation Photosynthesis

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