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Objective: To explore the effect of three interventions including caloric restriction, rope-skipping exercise and caloric restriction combined with rope-skipping exercise on cardiometabolic risk factors in overweight or obese college students. Methods: This study was a pilot randomized controlled trial. Overweight or obese students who met the inclusion criteria were recruited at Sun Yat-sen University in September 2019 and were randomly divided into four groups: caloric restriction group (CR), rope-skipping group (RS), combined group (CR-RS) and control group (CT). The intervention in each group lasted 8 weeks, specifically: the daily energy intake of CR was 100% to 110% of the basal metabolic energy; RS was instructed to rope three times a week, and CR-RS combined caloric restriction with rope-skipping. At the baseline and end of 8-week intervention, basic information, anthropometric indicators and fasting vein blood of students were collected. Paired t test and Wilcoxon paired-samples signed rank test were used for comparison before and after intervention, and analysis of covariance was used for comparison between groups after intervention. Results: A total of 29 students completed the trial and were included in the final analysis (7, 9, 7 and 6 students in CR, RS, CR-RS and CT, respectively). The mean age of students were (19.00±1.00) years, including 11 males and 18 females. The baseline characteristics of four groups were comparable. After 8 weeks of intervention, compared with CT, there was an increase in the body fat percentage and fat mass index in CR and CR-RS ( P <0.05). Insulin level decreased in CR-RS ( P <0.05). Systolic blood pressure in CR and diastolic blood pressure in CR-RS were higher ( P <0.05). Compared with baseline, fat mass index decreased in CR ( P <0.05), while body weight, BMI, and fat mass index decreased in CR-RS ( P <0.05). Conclusion: It is suggested that the caloric restriction alone and calorie restriction combined with rope-skipping exercise can benefit overweight or obese college students with cardiometabolic risk factors.

From September to October 2013, five in-stream tracer experiments involving slug additions of chloride were performed in Guanzhenhe Branch, a headwater stream in suburban Hefei. From the perspective of different transport mechanisms such as transient storage, lateral inflow and advection-dispersion, four scenarios were set to analyze the effects of transient storage on solute transport in the drainage ditch. And sensitivity analysis of parameters in OTIS model was conducted. The results showed that transient storage exerted a significant influence on the peak values of simulated chloride concentration breakthrough curves (BTCs) in the main channel, and the REs (relative errors) of peak values in the BTCs ranged from 24.23% to 117.26%, which were much higher than those of the peak times. Meanwhile, the effects on simulated BTCs of transient storage markedly exceeded those of lateral inflow. Correlation analysis results showed that A(s)/A were significantly correlated with the peak value REs and the peak time RE's, respectively. Moreover, the ranking of parameter sensitivity in OTIS model was A > A(s) > α > D.

To investigate the characteristics of ammonium and phosphorus retention in two typical channel forms, deep pool and winding ditch in headwater stream, four field tracer experiments were conducted in a first-order stream of Ershibu River in Hefei suburban, in which a solution of biologically active (NH4Cl and KH2PO4) and conservative (NaCl) tracers was released to the head of each reach at a constant rate. According to the data sets of tracer experiments, mechanisms of ammonium and phosphorus retention were interpreted by using OTIS model code, transient storage metrics and nutrient spiraling theory. Study results showed that: (1) The value of As in deep pool was larger than that in winding ditch, whereas its value of hydrological parameter α was lower by an order of magnitude than that of winding ditch; (2) The value of NH(4)+ -λ in main channel was higher by two to three orders of magnitude than that of NH(4)+ -λs,in transient storage zone in deep pool, but in winding ditch the two parameters were closer in terms of numerical size; (3) In deep pool, the value of NH+(4) -Vf was higher by an order of magnitude than that of SRP-Vf, in winding ditch, however, not only the two values of NH(4)+ -Vf and SRP-Vf were close to each other, but NH(4)+ -Sw was nearly equal to SRP-Sw in numerical size as well; (4) The value of NH(4)+ -U was larger by two to three orders of magnitude than that of SRP-U in deep pool, whereas in winding ditch NH(4)+ -U was just larger by one to two orders of magnitude than SRP-U in size; (5) In general, significant difference existed between deep pool and winding ditch in the effect on ammonium and phosphorus retention, and marked retention efficiency was observed for ammonium rather than SRP in deep pool.

Within the drainage basin, information about natural processes and human activities can be recorded in the chemical composition of riverine water. The analysis of the Guijiang River, the first level tributary of the Xijiang River, demonstrated that the chemical composition of water in the Guijiang River was mainly influenced by the chemical weathering of carbonate rocks within the drainage basin, in which CO2 was the main erosion medium, and that the weathering of carbonate rock by H2SO4 had a remarkable impact on the water chemical composition in the Guijiang River. Precipitation, human activities, the weathering of carbonate rocks and silicate rocks accounted for 2.7%, 6.3%, 72.8% and 18.2% of the total dissolved load, respectively. The stable isotopic compositions of dissolved inorganic carbon (delta13C(DIC)) indicated that DIC in the Guijiang River had been assimilated by the phytoplankton in photosynthesis. The primary production of phytoplankton contributed to 22.3%-30.9% of particulate organic carbon (POC) in the Guijiang River, which implies that phytoplankton can transform DIC into POC by photosynthesis, and parts of POC will sink into the bottom of the river in transit, which leads into the formation of burial organic carbon.