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中国对虾类产品进口贸易现状与对策建议

渔业信息与战略 2024年第2期39卷 83-90页

作者：岳冬冬李欣童李梦龙中国水产科学研究院东海水产研究所农业农村部远洋与极地渔业创新重点实验室上海200090 全国水产技术推广总站中国水产学会北京100125 中国水产科学研究院北京100141

对虾是全球虾类贸易的重要产品之一,中国对虾养殖与贸易具有重要的风向标作用。为掌握近年来中国对虾类产品进口贸易变化特征,对2017—2021年贸易规模、进口来源、产品类型等进行了分析。主要结论为:中国进口对虾类产品呈现量额齐增的趋... 详细信息

对虾是全球虾类贸易的重要产品之一,中国对虾养殖与贸易具有重要的风向标作用。为掌握近年来中国对虾类产品进口贸易变化特征,对2017—2021年贸易规模、进口来源、产品类型等进行了分析。主要结论为:中国进口对虾类产品呈现量额齐增的趋势,进口量年均增长88.15%,进口额年均增长72.32%。对虾类产品进口具有明显的周期性,分别形成1—6月份和7—12月份2个波动阶段。冻对虾和冻对虾仁是主要进口产品类型,这两类产品进口量额占比分别为96.83%和95.37%。中国南美白对虾养殖生产者价格6.99美元·kg-1,高于其他6个主要养殖国家生产者价格平均值39.31%。提出加强对虾类产品进口贸易监测,开展对虾产业战略研究,保障进口产品质量安全等对策建议,促进中国对虾养殖业和进口贸易协调稳定发展。

关键词：对虾进口南美白对虾生产者价格

The Relationship between Rural Left-Behind Children’s Physical Activity and Hope:The Mediating Effects of Perceived Social Support

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International Journal of Mental Health Promotion 2023年第9期25卷 1033-1039页

作者： menglong li Yujia Ren Hunan First Normal University Changsha410205China

It has been confirmed in previous studies that there is a positive correlation between physical activity and hope.In this study,rural left-behind children in China was taken as the participants to investigate the impact of physical activity on hope in rural left-behind children and examine the mediating role of perceived social support in the relationship between physical activity and hope.797 valid copies of the questionnaire were collected from China.Pearson correlation coefficient was employed to analyze the relationship between physical activity and hope;SEM and Bootstrap were used to test the mediating effect of perceived social support.The results show that physical activity can not only directly and positively predict the level of hope in rural leftbehind children but can also predict the level of hope through perceived social support;perceived social support plays a mediating role in the relationship between physical activity and hope.These results highlight the necessity to pay more attention to the physical activity of left-behind children and the possibility to improve the level of hope by increasing their physical activity;at the same time,the acquisition of more material,emotional and psychological support from teachers and guardians is more conducive to improving the sense of hope in left-behind children.These findings can deepen the understanding of the sense of hope in left-behind children,and provide new methods for and enlightenments on improving the level of hope in left-behind children.

关键词： Left-behind children physical activity hope perceived social support mediating role

Association between serum levels of TSH and free T4 and per- and polyfluoroalkyl compounds concentrations in pregnant women

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Journal of Environmental Sciences 2023年第2期124卷 11-18页

作者： Aijing li Jian Hou Jianjie Fu YinanWang Yifei Hu Taifeng Zhuang menglong li Maoyong Song Guibin Jiang State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of ScienceBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Department of Epidemiology and Biostatistics College of Public HealthZhengzhou UniversityZhengzhou 450001China Beijing Obstetrics and Gynecology Hospital Capital Medical UniversityBeijing 100026China Department of Child Adolescent Health and Maternal CareSchool of Public HealthCapital Medical UniversityBeijing 100069China

Many per-and polyfluoralkyl substances(PFASs)may disrupt maternal thyroid hormone homeostasis in pregnancy.Concerns should be raised regarding the PFASs exposure in pregnant women because thyroid hormones are involved in the early development of the fetus.In this study,we measured the concentrations of 13 PFASs,including five novel shortchain PFASs,in serum from 123 pregnant women in Beijing,China.linear regression models were used to investigate the association between thyroid-stimulating hormone(TSH)or free thyroxine(FT4)levels and PFASs concentrations under consideration of the impacts of pregnancy-induced physiological factors.We found that perfluorobutanoic acid(PFBA)(β=0.189,95%CI=-0.039,0.417,p=0.10)and perfluorodecanoic acid(PFDA)(β=-0.554,95%CI=-1.16,0.049,p=0.071)were suggestive of significant association with TSH in thyroid peroxidase antibody(TPOAb)negative women.No association was observed between all PFASs and FT4 levels after controlling for these confounding factors,such as BMI,gestational weight gain and maternal age.These findings suggest that it should pay more attention to the association between thyroid hormone levels and short-chain PFASs concentrations.Future studies could consider a greater sample and the inclusion of other clinical indicators of thyroid function,such as free T3 and total T3.

关键词： Per-and polyfluoralkyl substances Short-chain perfluoroalkyl acids Thyroid hormone Thyroid peroxidase antibody

Public Square Dancing Intervention on Subjective Well-Being of Middle-Aged and Elderly People:A Meta-Analysis

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International Journal of Mental Health Promotion 2022年第1期24卷 129-142页

作者： menglong li Xia Jiang Yujia Ren Physical Education Institute Hunan First Normal UniversityChangsha410205China Wuhan Sports University Wuhan430079China

Objective:To understand the influence of public square dancing on the subjective well-being of middle-aged and elderly people.Methods:According to the principle of Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines,we search Chinese databases,such as CNKI,Wanfang Data,and VIP,and English databases,such as Proquest,Web of Science,Pubmed,Cochrane,and ScienceDirect,and collect relevant articles at home and abroad from 2006 to December 2019 for meta-analysis in January 2020.Result:A total of 10 articles were included.The meta-analysis results showed that the well-being of middle-aged and elderly people in the public square dancing intervention group was significantly higher than that of the other exercise group and control group(both P0.05).No significant difference was found between the groups with weekly intervention frequency(P>0.05).Conclusion:Public square dancing intervention is effective for middle-aged and elderly people’s subjective well-being.Neither mixed intervention nor the times of weekly intervention have an impact on the intervention effect.However,the length of duration of intervention influences the intervention effect.

关键词： Middle-aged and elderly people subjective well-being meta-analysis square dancing

HIV-Positive Men Are More likely to Be Hyper linked Within College Student Social Network-Northeast China,2017-2018

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China CDC weekly 2022年第43期4卷 951-955页

作者： menglong li Huichao Wu Hongmei Yan Jiawulan Zunong Hongtao Hui Hailong li Zhenhua Yang Sten HVermund Yifei Hu Department of Child Adolescent Health and Maternal CareSchool of Public HealthCapital Medical UniversityBeijingChina General Management Office Xidan CampusPeking Union Medical College HospitalBeijingChina Department of HIV/STD Prevention and Control Heilongjiang Provincial Center for Disease Control and PreventionHarbin CityHeilongjiang ProvinceChina Heilongjiang Kangtong Community Harbin CityHeilongjiang ProvinceChina School of Computer and Information Engineering Harbin University of CommerceHarbin CityHeilongjiang ProvinceChina Dean of the office Yale School of Public HealthYale UniversityNew HavenCTUSA.

What is already known about this topic?Men who have sex with men(MSM)bear a disproportionate burden of new human immunodeficiency virus(HIV)infections and young MSM demonstrate parallel internet-driven HIV incident infection and dynamic social network.What is added by this report?The HIV positive prevalence and incidence among college MSM were 3.8%and 2.9 per 100 person-years,respectively,while these rates were 13.9%and 10.5 per 100 person-years,respectively,among their social contacts.The overall HIV positive prevalence was 7.2%in Northeast China.HIV-positive MSM have comparatively more social contacts than HIVseronegative MSM.What are the implications for public health practice?Hyper-linkages found in app-based social networks play an important role in HIV transmission via risky sexual behavior and suggest options for online intervention to promote HIV prevention.

关键词： Northeast prevalence HIV

Factors that Affect the Frequency of HIV Testing in College Men Who Have Sex with Men--Northeast China,2017-2018

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China CDC weekly 2022年第25期4卷 549-553页

作者： menglong li Huichao Wu Wen Shu Ziang li Hongmei Yan Hongtao Hui Hailong li Zhenhua Yang Sten H.Vermund Yifei Hu Department of Child Adolescent Health and Maternal CareSchool of Public HealthCapital Medical UniversityBeijingChina General Management Office Xidan CampusPeking Union Medical College HospitalBeijingChina Department of HIV/STD Prevention and Control Heilongjiang Provincial Center for Disease Control and PreventionHarbin CityHeilongjiang ProvinceChina Heilongjiang Kangtong Community Harbin CityHeilongjiang ProvinceChina School of Computer and Information Engineering Harbin University of CommerceHarbin CityHeilongjiang ProvinceChina Yale School of Public Health Yale UniversityNew HavenCTUSA.

Summary What is already known about this topic?Human immunodeficiency virus(HIV)testing is a critical tool in reducing HIV transmission among men who have sex with men(MSM);young MSM frequently use mobile phone applic... 详细信息

关键词： Northeast immunodeficiency hook

大学生领悟社会支持对其学业成就的影响——积极心理资本的中介作用

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西部学刊 2024年第13期 84-88页

作者：尤妙李梦龙朱丛杉李方超西安美术学院西安710065 烟台南山学院烟台265713 西北农林科技大学杨凌712100

为了深入探讨大学生对社会支持的认知、积极心理资本以及学业成就之间的相互关系,以A高校的1 681名学生为研究对象,通过收集他们对社会支持的认知、积极心理资本以及学业成就的相关数据并进行分析。研究结果表明:大学生对社会支持的认... 详细信息

为了深入探讨大学生对社会支持的认知、积极心理资本以及学业成就之间的相互关系,以A高校的1 681名学生为研究对象,通过收集他们对社会支持的认知、积极心理资本以及学业成就的相关数据并进行分析。研究结果表明:大学生对社会支持的认知、积极心理资本与学业成就之间存在显著的正相关关系,即大学生对社会支持的认知和积极心理资本对其学业成就产生了显著的正向影响。此外,大学生的积极心理资本在其对社会支持的认知与学业成就的关系中起到了部分中介的作用。

关键词：大学生领悟社会支持积极心理资本学业成就

High-sensitive state perception method for inverter-fed machine turn insulation based on FrFT-Mel

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Global Energy Interconnection 2024年第2期7卷 155-165页

作者： Ruitian Fan Xing Lei Tao Jia menglong Qin Hao li Dawei Xiang College of Electrical Power Engineering Shanghai University of Electric PowerShanghai 200090P.R.China State Grid Shanghai Municipal Electric Power Company Shanghai 200437P.R.China State Grid Technology College Shandong 250002P.R.China College of Electronics and Information Engineering Tongji UniversityShanghai 201804P.R.China

Amidst the swift advancement of new power systems and electric vehicles,inverter-fed machines have progressively materialized as a pivotal apparatus for efficient energy conversion.Stator winding turn insulation failure is the root cause of inverter-fed machine breakdown.The online monitoring of turn insulation health can detect potential safety risks promptly,but faces the challenge of weak characteristics of turn insulation degradation.This study proposes an innovative method to evaluate the turn insulation state of inverter-fed machines by utilizing the fractional Fourier transform with a Mel filter(FrFT-Mel).First,the sensitivity of the high-frequency(HF)switching oscillation current to variations in turn insulation was analyzed within the fractional domain.Subsequently,an improved Mel filter is introduced,and its structure and parameters are specifically designed based on the features intrinsic to the common-mode impedance resonance point of the electrical machine.Finally,an evaluation index was proposed for the turn insulation state of inverter-fed machines.Experimental results on a 3kW permanent magnet synchronous machine(PMSM)demonstrate that the proposed FrFT-Mel method significantly enhances the sensitivity of turn insulation state perception by approximately five times,compared to the traditional Fourier transform method.

关键词： State perception Turn insulation Switching oscillation Fractional Fourier transform Mel filter

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北京市6~8岁儿童心血管健康的性别差异

中国学校卫生 2024年第1期45卷 36-40页

作者：关梦颖江晓峰书文李梦龙肖惠迪叶尔林·阿斯哈尔胡翼飞首都医科大学公共卫生学院儿少卫生与妇幼保健学系北京100069

目的探索北京市6~8岁儿童心血管健康(CVH)的性别差异,为CVH相关生活方式的早期干预提供依据。方法基于北京儿童生长与健康队列(PROC)1914名6~8岁儿童的体格检查、问卷调查、实验室检测数据,根据生命八要素(life’s Essential 8)评分标... 详细信息

目的探索北京市6~8岁儿童心血管健康(CVH)的性别差异,为CVH相关生活方式的早期干预提供依据。方法基于北京儿童生长与健康队列(PROC)1914名6~8岁儿童的体格检查、问卷调查、实验室检测数据,根据生命八要素(life’s Essential 8)评分标准计算儿童CVH评分及其分项(健康行为)和(健康因素)评分,并分为较高、中等、较低3个等级;采用χ^(2)检验和Wilcoxon秩和检验比较性别差异。结果1914名儿童中,较高、中等、较低CVH的比例分别为35.7%,63.5%,0.8%,健康行为评分比例分别为25.9%,67.5%,6.6%,性别间差异均无统计学意义(χ^(2)值分别为2.30,0.07,P值均>0.05)。男童和女童较高、中等、较低健康因素评分比例分别为61.1%,36.0%,2.9%和71.1%,28.4%,0.5%,差异有统计学意义(χ^(2)=31.88,P0.05)。相比于男童,较低和中等CVH组的女童健康行为评分更低,健康因素评分更高。结论北京市6~8岁儿童心血管健康大多处于良好及以上水平。可通过改善生活方式、监测健康因素指标,特别是男童的实验室检测指标,进而提高儿童CVH水平。

关键词：心血管系统性别因素儿童健康行为