Mobility in China, 2020: a tale of four phases

2020 was an unprecedented year, with rapid and drastic changes in human mobility due to the COVID-19 pandemic. To understand the variation in commuting patterns among the Chinese population across stable and unstable periods, we used nationwide mobility data from 318 million mobile phone users in China to examine the extreme fluctuations of population movements in 2020, ranging from the Lunar New Year travel season (chunyun), to the exceptional calm of COVID-19 lockdown, and then to the recovery period. We observed that cross-city movements, which increased substantially in chunyun and then dropped sharply during the lockdown, are primarily dependent on travel distance and the socio-economic development of cities. Following the Lunar New Year holiday, national mobility remained low until mid-February, and COVID-19 interventions delayed more than 72.89 million people returning to large cities. Mobility network analysis revealed clusters of highly connected cities, conforming to the social-economic division of urban agglomerations in China. While the mass migration back to large cities was delayed, smaller cities connected more densely to form new clusters. During the recovery period after travel restrictions were lifted, the netflows of over 55% city pairs reversed in direction compared to before the lockdown. These findings offer the most comprehensive picture of Chinese mobility at fine resolution across various scenarios in China and are of critical importance for decision making regarding future public-health-emergency response, transportation planning and regional economic development, among others.     

乒乓球运动员击球落点预测能力分析

分析影响乒乓球运动员进行落点预测判断正确率的因素,探讨高水平、一般水平运动员和新手间在乒乓球落点预测判断上产生差异的因素,实验结果表明乒乓球及早、正确的预测判断能力可能和击球落点理解有较大关系。乒乓球落点方向判断能力上为运动员的选材提供了一些有益的参考,为乒乓球运动员的训练提供一些依据。     

抗阻/耐力训练诱导骨骼肌分子响应的比较研究

不同的运动方式诱导骨骼肌产生的适应性改变及分子响应机制不同。抗阻训练诱导骨骼肌发生肥大,其响应分子包括：PI3K、Akt、TSC1/2、mTOR、4EBP1、p70S6K等信号分子;耐力训练诱导骨骼肌的线粒体生物合成,其响应机制与AMPK、p38MAPK、CaMK、PGC-lα、NRF1、MEF2C等信号分子有关。     

“南海问题”与中国因应之策

南海自古以来就是中国的领土,中国对南海诸岛及其附近海域拥有无可争辩的主权。南海由于其重要的战略价值及丰富资源而成为东南亚相关国争夺的焦点,围绕南海主权展开的斗争愈演愈烈,南海战略态势日趋复杂化与白热化。鉴于此,中国应采取合理与务实的南海策略。     

住房价格变动对居民消费的影响效应研究——基于山西省的实证分析

本文利用1990-2008年的住房价格和居民消费时间序列数据,构建了山西省住房价格和居民消费的VAR模型。VAR模型的脉冲响应分析表明,住房价格、人均国内生产总值、居民消费水平、居民人均住房面积、居民可支配收入对住房价格的长期响应均为正,但短期和中期影响各不相同。住房价格对自身的短期冲击是正向的,在中期内表现出不确定性;住房价格对人均国内生产总值、居民人均住房面积、人均可支配收入的短期影响非常弱,但在中期内,对人均国内生产总值表现出不确定性,对居民人均住房面积的中期冲击为正向,对人均可支配收入影响非常弱;住房价格在短期内对居民消费水平有抑制作用,但在中长期内具有正向促进作用。     

中国农产品在产销间价格传导机制研究

本文选取农产品生产价格总指数(SCJG)和食品零售价格指数(SPLS)作为产销价格信号,采用国家统计局公布的1978年-2009年的年度数据,运用向量误差修正模型(VECM)、脉冲响应函数和方差分解法对中国产地市场SCJG和销地市场SPLS的价格传递机制进行了实证分析。结果表明:从长期来看,产地市场SCJG对销地市场VE的CMSP模LS型存的在结协果整也关表系明,S,C我JG国与产L销SJG间之农间产存品在价着格正传相导关的性长,S期CJ均G衡每关变系动制1%约,引着发短销期地价市格场波S动PL,S其变误动差1修.08正0%项;(vecm)的系数为0.58,符合正向修正机制,变量向均衡方向的调整速度较快,且这种制约作用能自动减弱价格之间的偏离,促使各种价格走向均衡。从短期看,脉冲响应函数和方差分解的分析结果显示,LSJG的上涨对SCJG的传导路径顺畅,但SCJG对SPLS的价格传导存在1期滞后,且产地的农产品市场价格对销地市场的传递效应随着时间的推移越来越明显,而销地市场SPLS对产地市场SCJG的影响逐渐增加但效果却微乎其微。为此,我国要加强产地农产品生产者价格形成机制的动态研究,不断健全我国农产品生产成本动态监测预警系统,合理引导农民生产,推动国内农业健康稳定发展。     

Multidimensional Forced-Choice CAT With Dominance Items: An Empirical Comparison With Optimal Static Testing Under Different Desirability Matching

Several forced-choice (FC) computerized adaptive tests (CATs) have emerged in the field of organizational psychology, all of them employing ideal-point items. However, despite most items developed historically follow dominance response models, research on FC CAT using dominance items is limited. Existing research is heavily dominated by simulations and lacking in empirical deployment. This empirical study trialed a FC CAT with dominance items described by the Thurstonian Item Response Theory model with research participants. This study investigated important practical issues such as the implications of adaptive item selection and social desirability balancing criteria on score distributions, measurement accuracy and participant perceptions. Moreover, nonadaptive but optimal tests of similar design were trialed alongside the CATs to provide a baseline for comparison, helping to quantify the return on investment when converting an otherwise-optimized static assessment into an adaptive one. Although the benefit of adaptive item selection in improving measurement precision was confirmed, results also indicated that at shorter test lengths CAT had no notable advantage compared with optimal static tests. Taking a holistic view incorporating both psychometric and operational considerations, implications for the design and deployment of FC assessments in research and practice are discussed.     

家庭应对灾害的基本策略

当灾害发生的时候,家庭有各种各样的反应。作者从社会学的理论视角出发。采用实地调查和文献法研究了家庭对灾害警报的反应、灾中家庭避难和灾后家庭救助等问题。在此基础上作者提出了家庭减灾的基本策略。     

单片机控制的多功能交流稳压电源的硬件研制

本文提出了一种新颖的单片机控制的多功能交流稳压电源,论述了工作原理,给出了硬件框图,该电源实现了智能化、多功能、高精度,还具有定时电源输出,智能闹钟等功能。