Cross-Sectional Associations of Lifestyle Behaviors with Depressive Symptoms in Adolescents

This study aimed to examine the associations between lifestyle behaviors and depressive symptoms in adolescents.Self-reported data from the 2019 Youth Risk Behavior Survey(YRBS)was analyzed.Depressive symptoms were set as the outcome variable.Movement variables(physical activity,muscle-strengthening exercise,physical education attendance,sports team participation,television watching,video or computer games,and sleep),eating behaviors(fruit intake,vegetable intake,milk intake,and eating breakfast or not),and substance use(alcohol use and cigarette use)were included as explanatory variables.Binary logistic regression was used to explore the asso-ciations between lifestyle behaviors and depressive symptoms after adjusting for sex,age,grade,race,and weight status.Of 13,677 participants who completed the investigation,girls were more than boys(50.3%vs.48.6%).The proportion of participants in grades 9,10,11,and 12 was 26.6,27.2,24.3,and 20.8,respectively.Of them,the prevalence of depressive symptoms was 36.0%(weighted%:36.7%[35.1%,38.3%]).Among all the lifestyle behaviors included,participating in no sports teams(OR=1.53[1.32,1.77]),spending more than 2 h in video or computer games(OR=1.64[1.40,1.92]),sleeping less than 8 h nightly(OR=1.79[1.45,2.20]),not eating breakfast(OR=1.56[1.37,1.78]),alcohol use(OR=1.74[1.49,2.02]),and cigarette use(OR=1.83[1.42,2.37])were associated with higher odds of depressive symptoms.To reduce depressive symptoms in adolescents,interventions can consider encouraging adolescents to engage in team sports activity,limit time for video or com-puter games,sleep enough,regularly eat breakfast,and avoid using alcohol and cigarette.Future studies are encouraged to verify our researchfindings by using a more improved study design.

黄河流域径流变化

The driving factors of runoff changes can be divided into precipitationfactor and non-precipitation factor, and they can also be divided into natural factor and humanactivity factor. In this paper, the ways and methods of these driving factors impacting on runoffchanges are analyzed at first, and then according to the relationship between precipitation andrunoff, the analytical method about impacts of precipitation and non-precipitation factors onbasin's natural runoff is derived. The amount and contribution rates of the two factors impacting onnatural runoff between every two adjacent decades during 1956-1998 are calculated in the YellowRiver Basin (YRB). The results show that the amount and contribution rate of the two factorsimpacting on natural runoff are different in different periods and regions. For the YRB, thenon-precipitation impact is preponderant for natural runoff reduction after the 1970s. Finally, bychoosing main factors impacting on the natural runoff, one error back-propagation (BP) artificialneural network (ANN) model has been set up, and the impact of human activities on natural runoffreduction in the YRB is simulated. The result shows that the human activities could cause a 77 x10^8 m^3·a^(-1) reduction of runoff during 1980-1998 according to the climate background of1956-1979.

Carbon sequestration in biomass and soil following reforestation:a case study of the Yangtze River Basin

The effect of reforestation on carbon sequestration has been extensively studied but there is less understanding of the changes that stand age and vegetation types have on changes in biomass carbon and soil organic carbon(SOC)after reforestation.In this study,150 reforested plots were sampled across six provinces and one municipality in the Yangtze River Basin(YRB)during 2017 and 2018 to estimate carbon storage in biomass and soil.The results illustrate that site-averaged SOC was greater than site-averaged biomass carbon.There was more carbon sequestered in the biomass than in the soil.Biomass carbon accumulated rapidly in the initial 20 years after planting.In contrast,SOC sequestration increased rapidly after 20 years.In addition,evergreen species had higher carbon density in both biomass and soil than deciduous species and economic species(fruit trees).Carbon sequestration in evergreen and deciduous species is greater than in economic species.Our findings provide new evidence on the divergent responses of biomass and soil to carbon sequestration after reforestation with respect to stand ages and vegetation types.This study provides relevant information for ecosystem management as well as for carbon sequestration and global climate change policies.

Analysis of the Leading Modes of Autumn Precipitation over the Yangtze River Basin

Based on daily precipitation data from 109 stations in the Yangtze River Basin(YRB)over the past 36 years(1980-2015),the Empirical Orthogonal Function(EOF)is employed to analyze changes in autumn precipitation.We used the monthly mean re-analysis datasets of atmospheric circulation and sea surface temperature(SST)to investigate the possible causes of the two leading modes,based on which the predictive equations were constructed and tested.The results of the EOF analysis show that the variance contribution of the first mode is 31.07%,and the spatial distribution shows a uniform variation over the whole region.The variance contribution of the second mode is 15.02%,and the spatial distribution displays a north-south dipole pattern in the YRB.The leading mode shows a dominant interannual variation,which is mainly due to the West Pacific subtropical high and anticyclones over the Philippine islands.The SST field corresponds to the positive phase of the eastern Pacific El Niño and the tropical Indian Ocean dipole.The second mode may be related to the Indian Ocean-East Asian teleconnection and early withdrawal of the summer monsoon.The SST field corresponds to a weaker central Pacific El Niño.Through a stepwise regression analysis,SST anomalies in some areas during summer show a good predictive effect on the autumn precipitation mode in the YRB region.

灾难后青少年群体自杀相关因素的调查

目的调查灾难后青少年群体的自杀相关因素,进一步探讨其自杀观念、计划和行为的发生率及其影响因素。方法采用一般资料问卷和青少年健康危险行为问卷(Youth Risk Behavior Survey,YRBS)自评量表,对2008年汶川地震国家划定的九个极重灾区的中小学校进行整群随机抽样。以班级为抽样单位,随机抽取110所中小学校的在校学生。收集中小学生的一般资料、灾后相关情况及YRBS中自杀因子评分。根据资料的类型不同,分别采用描述性统计、t检验、χ2检验,其中对自杀观念、自杀计划和自杀行为分别做单因素分析及多因素Logistic回归分析。结果共计发放自评问卷7 833份,收回问卷总计7 521份,回收率为96.02%,其中有效问卷6 875份(91.41%),无效问卷636份。调查结果发现:中小学生中曾认真考虑过自杀的比例为6.90%,有过自杀计划比例为4.00%,尝试采取过自杀行为的比例为2.70%。Logistic回归分析显示:(1)以是否曾认真考虑过自杀为因变量,年龄[OR=1.178,95%CI(1.098,1.178)]、灾后家庭结构发生变化[OR=1.360,95%CI(1.360,1.085)]是灾难后青少年群体自杀观念的危险因素。(2)以是否有过自杀的计划为因变量,年龄[OR=1.099,95%CI(1.050,1.150)]、被掩埋[OR=2.155,95%CI(1.104,4.205)]、灾后家庭结构发生变化[OR=1.495,95%CI(1.128,1.981)]是灾难后青少年群体自杀计划的危险因素。(3)以是否尝试采取过自杀行为为因变量,男性[OR=1.513,95%CI(1.122,2.039)]、灾后家庭结构发生变化[OR=1.555,95%CI(1.112,2.175)]是灾难后青少年群体自杀行为的危险因素。结论年龄和灾后家庭结构发生变化是自杀观念的危险因素,年龄、被埋和灾后家庭结构发生变化是自杀计划的危险因素,男性和灾后家庭结构发生变化是自杀行为的危险因素。灾后家庭结构改变是自杀观念、自杀计划和自杀行为共同的危险因素,故对灾后家庭结构变化的青少年应给予更多的心理评估和心理干预,以避免灾难后青少年群体自杀的风险。

Seasonal Rainfall Forecasts for the Yangtze River Basin of China in Summer 2019 from an Improved Climate Service

Rainfall forecasts for the summer monsoon season in the Yangtze River basin(YRB) allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate service was developed in 2016, producing a prototype seasonal forecast product for use by stakeholders in the region, based on rainfall forecasts directly from a dynamical model. Here, we describe an improved service based on a simple statistical downscaling approach. Through using dynamical forecast of an East Asian summer monsoon(EASM) index, seasonal mean rainfall for the upper and middle/lower reaches of YRB can be forecast separately by use of the statistical downscaling, with significant skills for lead times of up to at least three months. The skill in different sub-basin regions of YRB varies with the target season. The rainfall forecast skill in the middle/lower reaches of YRB is significant in May–June–July(MJJ), and the forecast skill for rainfall in the upper reaches of YRB is significant in June–July–August(JJA). The mean rainfall for the basin as a whole can be skillfully forecast in both MJJ and JJA. The forecasts issued in 2019 gave good guidance for the enhanced rainfall in the MJJ period and the near-average conditions in JJA. Initial feedback from users in the basin suggests that the improved forecasts better meet their needs and will enable more robust decision-making.

Synchronous Characteristics of Precipitation Extremes in the Yangtze and Murray–Darling River Basins and the Role of ENSO

The floods caused by the extreme precipitation in the Yangtze River basin(YRB)and Murray–Darling River basin(MDRB),the largest basins in China and Australia,have significant impacts on the society and regional economies.Based on the spatial–temporal analysis of the daily precipitation extremes(DPEs)during 1982–2016,we found that for both basins,the whole-basin-type DPEs have the highest proportion and a synchronous DPE interannual variation characteristic exists in the two basins,with the 3-yr running correlation coefficient of the annual DPE days(DPEDs)reaching almost 0.7(significant at the 0.01 level).The El Ni?o–Southern Oscillation(ENSO),which is one of the most significant climate disturbance factors in the world,plays an important role in modulating the variability of the DPEs in the two basins.Singular value decomposition(SVD)analysis revealed that both the YRB and the MDRB’s whole-basin-type DPEs are closely coupled with the procedure that the preceding winter eastern Pacific(EP)-type El Ni?o faded to a central Pacific(CP)-type La Nina.This means that the DPEs in the YRB and MDRB may synchronously occur more frequently when the above process occurs.Owing to the atmosphere–ocean interaction from the east–west dipole sea surface temperature(SST)anomaly pattern,the atmospheric circulation disturbance exhibits a pattern in which the equatorial eastern Pacific region is a mass source anomaly with a higher pressure,drier air,and weaker convection,while the equatorial western Pacific region is a mass sink anomaly with a lower pressure,wetter air,and stronger convection.Moreover,two wave trains that originated from the tropical western Pacific were found to extend to the YRB and MDRB.The interaction between the wave train’s interphase dynamics and water vapor transport disturbance results in the ascent conditions and enhanced water vapor transport,which leads to the synchronous occurrence of DPEs in the YRB and MDRB on an interannual scale.

An Integrated Flood Disaster Prevention System for the Sustainable Development of the Yangtze River Basin

Flood disasters have been a serious restraint to the sustainable development of the Yangtze River Basin (YRB). After analyzing the major causes to the flood disasters of YRB, the paper proposes an integrated flood disaster prevention system for the sustainable development of the YRB. The starting point of the system is to rationally coordinate the relationship of population, environment and economy.