Effects of spatio-temporal intervals between newly-hatched larvae on larval survival and development inMonochamus alternatus (Coleoptera: Cerambycidae)

The effects of distance between hatching larvae on survival and development were investigated inMonochamus alternatus. Two newly-hatched larvae were inoculated intoPinus densiflora bolts at a distance of 2.5 cm or 10 cm, simultaneously or at an interval of 2 weeks. Some larvae were inoculated singly as a control. When larvae were inoculated simultaneously, mortality of the closely-inoculated larvae was significantly higher than that of distantly-inoculated larvae. Such high mortality was identified as due to conspecific bites. When the two larvae were inoculated asynchronously, the first-inoculated larvae killed some second-inoculated larvae but were never killed by them. Consequently, mortality was higher in second-inoculated larvae than in first-inoculated larvae. In particular, there was a significant difference in mortality between them when the larvae had been inoculated closely. The mortality of second-inoculated larvae was higher in the closely-inoculated group than in the distantly-inoculated group although there was no significant difference between them. In the case of two simultaneously-inoculated larvae, the initial distance between them had no significant effect on the development and growth in the early larval stage. When the larvae were inoculated asynchronously, the first-inoculated larvae grew more quickly than singly-inoculated control larvae.     

关于当前生育影响因素的思考

根据我国生育水平来分析影响当前我国生育的因素,并结合社会经济发展,进一步探讨生育影响因素的未来变动与趋势。影响生育的经济因素、社会因素、自然因素以及资源分配或社会平等的政治因素与人们的生育意愿变化等都有抑制生育率提高的作用。生育政策变动、社会保障、人口健康和安全有促进生育率变化的趋向。     

家庭结构对老年人代际支持的影响研究

本文利用中国老年健康影响因素跟踪调查（CLHLS）项目2008年的数据,分析了家庭结构的变迁（表现为居住安排与子女数量两方面）对老年人所获得的来自子女的代际支持的影响。研究结论显示,是否与子女同住会影响老年人获得的经济支持、情感支持与照料支持,而子女数量对代际支持的获得有正向作用。     

中国外商直接投资就业效应传导渠道研究

随着我国外商直接投资的大量利用,以及就业问题的日益严重,外商直接投资就业效应值得关注。本文从一个新的角度———外商直接投资就业效应的三个传导渠道出发,分析了外商直接投资对我国就业的影响机制,然后在此基础上建立模型进行实证分析。因为近些年来外商进入我国越来越多的选择独资模式,因而特别在模型中加入反映外商直接投资独资化倾向的变量,来研究其对就业的影响。     

少数民族人口流动原因差异的民族因素影响分析

少数民族与汉族人口流动原因存在差异,利用2005年全国1%人口抽样调查数据,检验民族因素对这一差异是否产生影响。依据是否为少数民族和是否来自民族自治地方两个维度的民族因素将流动人口划分为四类,选取来自民族自治地方的少数民族和汉族流动人口、来自非民族自治地方的汉族流动人口作比较,作为自变量,人口流动原因为因变量。Logistic回归结果显著,民族因素对少数民族和汉族人口流动原因差异的影响是存在的。     

Effects of gall volume on survival and fecundity of gall-making aphidsAdelges japonicus (Homoptera: Adelgidae)

Summary The number of larvae reaching maturity within the gall ofAdelges japonicus was positively related to gall volume, and the relationship between the number of mature larvae and gall volume did not change with different densities of colonized larvae. The population changes in the bud galls ofA. japonicus were surveyed by collecting the galls, which did not suffer predation or parasitism within the galls, from young artificial plantations ofPicea jezoensis over two years. In the year when the density of colonized larvae was high, they suffered a 42% mortality within the galls, whereas mortality was nearly zero in the low density year. The numbers of larvae per gall were positively correlated with gall volume. The regression lines of the number of colonized larvae on gall volume did not differ significantly in the regression coefficients between the two years, whereas the intercept was significantly higher in the year when the density of colonized larvae was higher. However, different within-gall mortality nullified this difference, and the regression lines of the number of mature larvae on gall volume had no significant difference both in the regression coefficients and the intercepts. This suggests that the number of mature larvae per gall was limited by available resources within the gall which were positively related to gall volume. In 25% of the galls in which mature larvae inhabited, the space within the galls were completely filled by the larvae, indicating that space was one of the limiting resources. Gall volume also affected the number of adults that emerged from the gall and the potential number of their progeny.     

健康状况和健康冲击对工作时间的影响

使用中国健康与养老追踪关于浙江和甘肃两省的预调查数据,估计居民健康存量状况和健康冲击对劳动工作时间的影响。研究采用三种健康状况指标:自评健康状况、四种常见慢性病和日常生活自理能力(ADL),其中自评健康状况还使用了15岁之前的健康状况做工具变量估计。基于Tob it模型的估计结果显示:只要健康状况不是太差,劳动者一般不会选择完全退出劳动力市场,健康状况较差的劳动者会适当减少工作时间。慢性病中,只有关节类的疾病对劳动时间的影响显著,其他疾病对劳动时间没有显著影响。日常生活自理能力强的人工作时间明显要长。健康冲击会显著减少劳动者的工作时间,进而减少收入。尽管男性和女性在工作小时上存在很大差异,但是估计结果显示健康存量状况和健康冲击对工作小时的影响不存在很大的性别差异。     

Data on survival of recent births as a source of child mortality estimates in the developing world: An assessment of census data

In many less developed countries, household surveys collect full and summary birth histories to provide estimates of child mortality. However, full birth histories are expensive to collect and cannot provide precise estimates for small areas, and summary birth histories only provide past child mortality trends. A simple method that provides estimates for the most recent past uses questions about the survival of recent births in censuses or large household surveys. This study examines such data collected by 45 censuses and shows that on average they tend to underestimate under-5 mortality in comparison with alternative estimates, albeit with wide variations. In addition, the high non-sampling uncertainty in this approach precludes its use in providing robust estimates of child mortality at the country level. Given these findings, we suggest that questions about the survival of recent births to collect data on child mortality not be included in census questionnaires.     

劳动力就业城市选择对城市工资溢价的影响

中国逐步从定居社会转变为流迁社会,劳动力大范围流动体现在就业城市的自主选择上,该行为对城市工资溢价产生持续影响,同时城市工资溢价又影响劳动力的就业城市选择。利用2017年中国流动人口动态监测调查数据,构建包含个体选择的处置效应模型,实证分析发现,中国存在城市工资溢价现象,劳动力的异质性特征和城市差异性特征显著影响就业城市选择行为;纠正劳动力城市选择的内生二元选择偏差后,发现中国特大城市和超大城市的工资溢价变大,而大城市的工资溢价消失,中小城市工资比大城市更有竞争力。中国城市体系中的首尾优势是劳动力理性选择就业城市的结果,这为中国实施差异化的城市发展政策来实现城市体系的整体优化和内部协调提供了新思路。     

The Effect of Depressive Symptoms on the Association between Functional Status and Social Participation

The aim of the current study was to examine the interactive effects of depressive symptoms and lower extremity functioning on social participation for a group of moderately to severely disabled older women. The study used a cross-sectional community based sample, enrolled in the Women’s Health and Aging Study I, randomly selected from the Centers for Medicare & Medicaid Services enrollment files for women living in the Baltimore, Maryland area. The participants were women aged 65 or older who completed the in-person interview (n = 999). After adjusting for demographics and risk factors, each unit increase in the Short Physical Performance Battery (SPPB) score was associated with a 0.31 point increase in satisfaction with social participation for the non-depressed group, and 2.04 points for the depressed group. Depressive symptoms and lower extremity functioning interact to affect satisfaction with social participation. Among women with high depressive symptoms the gradient of association with social participation increased sharply with better lower extremity function compared with non-depressed women, where the gradient of association was moderate. The findings suggest the potential value of programs that focus on improving lower extremity function among older high risk groups.     

社会资本对受雇就业农民工职业地位获得的作用

本文以空位竞争模型中对劳动力市场中工作结构与奖励结构的假定为基础,进一步地在理论上推演出了社会资本对农民工职业地位获得作用的假设。对实地调查数据的分析发现:尽管职业流动的频率越高越不利于农民工获得专业技术或管理等较高职业地位,但对于社会关系的广度高的个体,职业流动频率对职业地位的晋升具有正向作用。该结果意味着职业流动频率高并不一定不利于农民工职业地位的获得,在缺乏社会关系广度下的频繁职业流动才是导致农民工水平职业流动的原因。     

人口转变的经济增长效应研究新进展：一个综述

关于人口转变对于经济增长的效应研究由来已久,但是研究大多只考虑了人口数量和人口增长率对于经济增长的效应。近二十年来,许多经济学家在揭示“东亚奇迹”和中国经济腾飞等一系列经济现象的原因时。发现了人口年龄结构对于经济增长的重要贡献,并提出了“人口红利”的概念以解释经济发展。本文将具体介绍近二十年来理论界对于人口转变影响经济增长的相关机制的研究以及经验分析。并对这些研究的政策含义和有待深入研究的问题作出简要评述。     

人口城乡结构变动对城镇失业保险需求的影响研究

人口城乡结构变动是引发失业保险需求增长的因素之一,本文在对失业保险需求概念及人口城乡结构变动对失业保险需求影响定性分析的基础上,构建了失业人口变动测算模型和失业保险需求测算模型。以陕西省为例的测算结果表明,引入人口城乡结构变动因素时的失业保险需求远大于不引入人口城乡结构变动时的失业保险需求,两者之间的差额从2010年的12.70亿元增长至2020年的31.72亿元,年均递增9.59%。     

人口老龄化的区域经济效应分析——基于新古典经济增长模型

人口老龄化与区域经济发展之间有着必然的内在关联性。因为生产和消费是区域经济发展中的重要环节,而人口老龄化对生产和消费均有影响,也就必然会影响区域经济的发展。因此,本文首先在梳理国内外相关研究的基础上提出人口老龄化对区域经济发展的双重效应——正效应和负效应;然后以新古典经济增长模型为基础,尝试引入人口老龄化因素从而对该模型进行扩展,分析得到的结论是:①进一步验证了人口老龄化对区域经济发展的双重效应的存在;②不同的区域,人口老龄化程度不同,人口再生产所处于的发展阶段不同,人口老龄化对区域经济发展的经济影响程度,即其正效应和负效应之和也就不尽相同,但存在的一个基本规律是,人口老龄化程度越高,其负效应就越大,其对区域经济发展的减速效应也就越明显。     

Effect of audit and feedback on the availability, utilisation and quality of emergency obstetric care in three districts in Malawi

BACKGROUND: Facility-based maternal death reviews and criterion-based clinical audit, were introduced in three districts in Malawi in 2006. RESEARCH QUESTION: Can audit and feedback improve the availability, utilisation and quality of emergency obstetric care (EmOC)? PARTICIPANTS AND METHODS: Observational study in which emergency obstetric care offered to women who gave birth in 73 health facilities (13 hospitals and 60 health centres) in three districts in Malawi in 2005 (baseline, 41,637 women) was compared to 2006 (43,729 women) and 2007 (51,085 women). RESULTS: The number of comprehensive and basic EmOC facilities did not change over the 3-year period (p for trend=1.000). Although institutional delivery rate decreased in 2006, overall it increased over 3 years (p for trend<0.001) - 31.8% (2005), 31.1% (2006) and 34.7% (2007), and Caesarean section rate was low and did not change (p for trend=0.257) - 1.7% (2005), 1.6% (2006) and 1.5% (2007). There was a significant increase in the met need for EmOC (p for trend<0.001) - 15.2% for 2005, 17.0% for 2006 and 18.8% for 2007. Maternal mortality decreased significantly from 250 per 100,000 women in 2005 to 222 in 2006 and 182 in 2007 (p for trend<0.001). Similarly, the case fatality rate decreased monotonically (p for trend<0.001) - 3.7% (2005), 3.0% (2006) and 1.5% (2007). DISCUSSION: Audit and feedback can improve availability, utilisation and quality of emergency obstetric care in countries with limited resources. CONCLUSION: There is need to increase availability of emergency obstetric care by upgrading some health centres to EmOC level through training of staff and provision of equipment and supplies.     

人口和计划生育利益导向政策“有利少导”现象例析

相比而言,利益导向政策在实际执行过程中,政策杠杆导向作用显弱。奖励扶助政策含金量不够、惩罚机制成效不大、普惠政策比较效应明显、政策实施部门缺少良好协作、非受益群众不关心等是主要原因。建议:协调政策,在普惠政策制定和执行中应考虑对计生家庭的优惠优先,计生优惠政策需相关政策协调支撑;部门配合,需要和强化机制定时进行协调并督促各部门履行职责,设立专门的奖励扶助办公室全面负责各级的计生利益导向政策;营造舆论,开展对领导干部、计生宣传干部和群众多层次的宣传;科学决策,在制定优惠政策时,充分注意群众需求的丰富性、多层次性和可持续性,适地适时加大政策的奖励力度。     

城市化过程中人口变动趋势对我国房地产开发的影响

城市化是中国经济现代化的重要标志。城市化过程中我国人口变化的趋势对城市房地产需求总量和结构产生重要影响,为房地产市场带来机遇和挑战。     

The Effect of HIV-Discordance on the Sexual Lives of Gay and Bisexual Men in Mexico City

Drawing upon 44 in-depth interviews with men in HIV-discordant gay couples (only one man is HIV-positive) in Mexico, I explore whether being aware of the risk of primary infection or re-infection leads to protected sex. The results have policy implications, as the findings show that a significant number of men have participated in unprotected sex. An explanation is that these men perceive unprotected sex as an expression of commitment to their relationship. On the other hand, those who reported always using protection during sex perceive that guarding each other's health provides mutual benefit and shows their commitment to their relationship.     

人口稀释效应对经济增长异质性的影响——基于人力资本积累、R&D传导的机理分析

将人口增长“稀释效应”嵌入一个四部门水平创新框架,提出一个同时内生化个体经济行为、R&D技术进步与人力资本积累的内生增长模型,推导并刻画了经济收敛于BGP均衡及影响经济增长率的因素,为解释人口增长对经济增长产生不确定影响的“正负符号之争”提供了微观基础分析。边际贡献在于:修正设定知识积累存在非规模效应且人力资本积累存在“稀释效应”,放宽对参数的上限或正负进行先验设定。得出结论:人口增长产生负向“稀释效应”与正向“思想效应”是影响经济增长的微观传导路径,正负效应共同作用门槛值大小的不同决定人口增长与经济增长呈非单调异质性不确定影响,进一步分析了稀释效应与门槛值之间的内在关联,数值模拟量化了参数效应。     

Quality of Life from the Voting Booth: The Effect of Crime Rates and Income on Recent U.S. Presidential Elections

Quality of Life (QOL) is often measured with surveys of citizen’s satisfaction. In contrast, the current research uses already-existing voting data to infer citizens’ perceptions of QOL. Under this model, citizens decide how much their QOL has improved (or declined) since the last election, and then vote to reward (or punish) the incumbent party accordingly. Analysis of the popular vote for the incumbent party then allows inference on how citizens judge their QOL and how they weight the various domains. Previous research has concluded that voters reward an incumbent who improves the economic domain prior to election. I test whether voters also reward declining crime rates, and estimate how citizens weight the relative importance of each in determining QOL. I analyze the vote shares by state from U.S. presidential elections from 1972 to 1996. Results show that changes in crime rates do influence vote share, consistent with the responsibility hypothesis, but to a smaller degree than the economic domain does. The method described provides convergent evidence that citizens weight domains differentially, and can provide the weights for a national QOL index.