Untangling the contributions of meteorological conditions and human mobility to tropospheric NO2 in Chinese mainland during the COVID-19 pandemic in early 2020     

Yuxiang Zhang  Haixu Bo  Zhe Jiang  Yu Wang  Yunfei Fu  Bingwei Cao  Xuewen Wang  Jiaqi Chen  Rui Li 《国家科学评论(英文版)》2021,8(11)

In early 2020, unprecedented lockdowns and travel bans were implemented in Chinese mainland to fight COVID-19, which led to a large reduction in anthropogenic emissions. This provided a unique opportunity to isolate the effects from emission and meteorology on tropospheric nitrogen dioxide (NO₂). Comparing the atmospheric NO₂ in 2020 with that in 2017, we found the changes of emission have led to a 49.3 ± 23.5% reduction, which was ∼12% more than satellite-observed reduction of 37.8 ± 16.3%. The discrepancy was mainly a result of changes of meteorology, which have contributed to an 8.1 ± 14.2% increase of NO₂. We also revealed that the emission-induced reduction of NO₂ has significantly negative correlations to human mobility, particularly that inside the city. The intra-city migration index derived from Baidu Location-Based-Service can explain 40.4% ± 17.7% variance of the emission-induced reduction of NO₂ in 29 megacities, each of which has a population of over 8 million in Chinese mainland.  相似文献   

福建农村社会化养老服务的模式、机制及其适应性研究     

和红 《华侨大学学报(哲学社会科学版)》2014,(4):134-140

依据"养老服务供给来源"可将福建现行农村养老服务模式划分为集中居住服务、农村居家养老服务和互助养老服务三种模式。每种模式有其独特的运作机制和建立及普及的适应性条件。处于起步阶段的福建农村社会养老服务不可避免存在着重建设轻管理、服务供需不匹配、区域发展的不均衡和专业服务人员缺乏等共性问题,须因地制宜地选择农村养老服务机构开办形式,规范养老服务机构和设施的运行,转变养老公共服务财政投入格局,加强专业养老服务队伍建设,以构建福建农村社会养老服务的可持续发展路径。  相似文献   

实验教学项目的开发设计与策略     

杨文明 《喀什师范学院学报》2014,(3):52-55

实验教学的一切活动起源于实验项目的设计与开发,实验教学项目的选择与设计直接决定了实验项目教学的效果。实验项目的开发与设计必须有其内在的动力或者逻辑原则,一个指导思想不明确的实验教学项目其意义也是不明确的,实验教学效果也将很难预测。  相似文献   

L_1正则化问题解的必要性条件     

吴焚供 《广东教育学院学报》2014,(5):36-38

利用凸集分离定理给出了一个L1正则化问题最优解存在的必要性条件.  相似文献   

巡回取货模式的应用条件分析——以奇瑞-邮政巡回取货项目为例     

韩媛媛 《滁州师专学报》2014,(4):66-68

巡回取货模式已经成为国内外汽车零部件入厂物流最先进的操作模式之一,备受汽车企业的推崇。国内众多汽车企业都先后实施过巡回取货模式,有成功的,也有失败的。奇瑞-邮政巡回取货项目正在摸索探讨中前进,还存在诸多问题。邮政物流巡回取货项目的完善还应具备一系列条件：如均衡的生产计划、良好的沟通、完善的信息应用等等。  相似文献   

k-path覆盖α-对角占优矩阵的充要条件     

邢楠  张纹纹 《洛阳师范学院学报》2014,(11):25-26

本文讨论了关于k-path覆盖α-对角占优矩阵中α存在的条件,进而给出了系列矩阵为k-path覆盖α-对角占优矩阵的充要条件.  相似文献   

室内空气中总挥发性有机物检测方法的优化     

潘锦  彭虹  张晓淳 《鹭江职业大学学报》2014,(5):102-106

建立了热脱附-毛细管气相色谱法测定室内环境空气中苯、甲苯、乙酸丁酯、十一烷、乙苯、对二甲苯、间二甲苯、邻二甲苯和苯乙烯等挥发性有机物的检测方法.该方法的色谱分析时间为20 min,比GB 50325-2010方法的52 min缩短了32 min,各物质峰分离程度均高于98%.9种挥发性有机物在一定浓度范围内标准曲线线性良好,相关系数均在0．998~0．999之间,检出限均低于5．0x10-4 mg/m3（采样体积1．0 L计）.实际样品的检测结果表明该方法操作简单、灵敏度高、数据准确可靠,满足分析要求.  相似文献   

富硒、富锌钝顶螺旋藻培养优化研究     

张爱萍  陈天仁  陈叶  祖廷勋  罗光宏 《河西学院学报》2014,(2):72-76

以钝顶螺旋藻为载体,以硒浓度、锌浓度和添加方法为因素,通过单因素和正交试验,确定富锌、富硒钝顶螺旋藻的最佳培养条件.结果表明:在钝顶螺旋藻培养液中加入硒浓度为8 ug/mL、锌浓度为7 ug/mL,加入方法为低水平培养4天(加入浓度的一半)、高水平培养4天(加入剩余一半),为富锌、富硒钝顶螺旋藻的最佳添加浓度和添加方法.  相似文献   

Supporting pre-service teachers to enhance the effectiveness of their classroom practice through engaging with the ‘voice’ of their pupils     

Elizabeth Anne Hopkins 《Teacher Development》2014,18(1):15-28

The research reported here was focussed on accessing the perceptions of pre-service teachers regarding the critical factors which support highly effective learning in schools in the United Kingdom. Their perceptions were arranged into a taxonomy so that they can be used as a starting point for their reflections on the observations they make of teaching and learning in schools with the aim of enhancing the effectiveness of their own teaching. The choice of technique used to access the perceptions was driven by the desire to provide the pre-service teachers with a method that they could use themselves to engage with the ‘voice’ of their own pupils regarding the factors which support effective learning. The engagement of pupil voice has become increasingly significant in understanding effective pedagogy and in securing more personalised approaches to learning in United Kingdom school contexts.  相似文献   

Motivational factors in discussing sexual health with young people with chronic conditions or disabilities     

Heleen A. Van der Stege  Sander R. Hilberink  Adriaan P. Visser  AnneLoes Van Staa 《Sex education》2014,14(6):635-651

The objective of this study was to identify determinants of professionals’ intention to use the new board game SeCZ TaLK to facilitate sexual health discussions with young people with chronic health conditions and disabilities, and to gauge whether intention led to actual use. A cross-sectional web-based survey of 336 professionals before they received the game sought to measure their intention to use SeCZ TaLK, their attitudes towards discussing sexuality, social professional environment, self-efficacy, opinion on the feasibility of using the game and experience discussing sexuality. Actual use of SeCZ TaLK was assessed at follow-up (N = 105). Professionals with higher self-efficacy and more experience in discussing sexual health were more likely to intend to use the game. At follow-up, intention to use explained 21% of the variance in actual use. SeCZ TaLK fits easily into the daily practice of professionals working in assisted-living and day-care facilities; other professionals experienced greater difficulty integrating the game into their practice. Despite this, SeCZ TaLk was also used across a wide range of settings including in psycho-educational groups, group consultations in hospitals and group therapy in rehabilitation centres. Professionals appreciated the board game SeCZ TaLK, but actual use depended on their own motivation and skills and compatibility with work routines.  相似文献