WIC Participation and Relative Quality of Household Food Purchases: Evidence from FoodAPS

We examine the effect of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on the quality of household food purchases using the National Household Food Acquisition and Purchase Survey (FoodAPS) and propensity score matching. A healthy purchasing index (HPI) is used to measure nutritional quality of household food purchases. WIC foods explain the improvement in quality of food purchases, not self‐selection of more nutrition‐conscious households into the program. The improvement in purchase quality was driven entirely by WIC participating households who redeemed WIC foods during the interview week. There was no significant difference between WIC participants who did not redeem WIC foods and eligible nonparticipants. In this sample, there is no evidence that lack of access to clinics has adverse effects on participation nor is there evidence that HPI depends on supermarket access. A supervised machine learning process supports our main conclusion on the importance of WIC foods.     

GPT3模型计算中国大陆对流层天顶延迟精度分析

为了评估GPT3模型计算中国大陆对流层延迟改正的精度和可靠性,利用2017-2018年欧洲中期天气预报中心的ERA-Interim大气廓线资料和中国地震局提供的陆态网对对流层延迟产品进行了对比验证分析。结果表明,在中国大陆,GPT3-ZTD模型值的年均偏差(Bias)小于0.6 cm,均方根误差(RMSE)优于3.53 cm。ZTD模型值的精度总体呈现出从中国西北(RMSE3 cm)到东南地区(RMSE5 cm)逐渐降低的趋势;在中国东南地区,GPT3模型低估了对流层天顶延迟,其量级处于-2.0～0.5 cm。ZTD模型值的精度与测站高程呈非线性相关,随着高程增加而精度不断提升。此外,GPT3-ZTD的精度具有明显季节性变化,RMSE基本维持在1～6 cm,ZTD模型值精度的季节性变化与大气中水气含量和变化剧烈程度相关。GPT3模型对中国大陆的对流层天顶延迟计算有较好的精度和可靠性,可为中国大陆对流层延迟改正建模提供一定参考。     

THE IMPACT OF GREATER AUTONOMY ON EFFICIENCY OF WORK AND QUALITY OF SERVICES IN PUBLIC SERVICE PROVIDERS: A CASE OF VOCATIONAL EDUCATION INSTITUTIONS

ABSTRACT: The paper analyses impact of greater autonomy on efficiency of work and quality of services in public service institutions. Autonomy is one of the key principles of New Public Management that, according to the theory, increases performance in public service providers. However this assumption has been scarcely researched in practice. To narrow this gap, the experimental reform that implemented greater managerial and financial autonomy in 13 Lithuanian state vocational schools was chosen for research. In order to analyse the impact of autonomy after the reform, maximally similar institutions (those that underwent the reform and that did not) are compared using quantitative (incl. counterfactual analysis) and qualitative methods. The results indicate that institutions that have been reformed tend to have better efficiency and quality of services, even though this relationship is not causal. Moreover, the research challenges the notion that such results came from greater autonomy. Finally, the logic of the NPM of as to why more autonomous institutions perform better is also challenged.     

我国自愿环境协议的第三方主体选择及其职能安排刍议

自愿环境协议在环境管制的实务中得以流畅运用,政府与企业以外的第三方主体对企业环境绩效所进行的评估功不可没。在我国,可由政府对从事环境服务业的法人实体开展资质认证,依此判断这些组织机构是否具备为协助政府与企业实施自愿环境协议所必要的环境审计能力,并根据所获得的结论建立第三方协议参与者官方认证资源库。通过认证的第三方在自愿环境协议中负责对企业进行环境审计、环境目标执行计划书评审和履约绩效监督,企业购买此类环境服务的费用享受公共财政的支持。     

木糖二级生化废水絮凝机理及条件的研究

文章通过选取几种不同的絮凝剂进行研究,来选出对木糖废水处理效果最佳的絮凝剂及其最佳絮凝条件、最佳去除率。从硫酸铝、三氯化铝、PAC、硫酸铁、硫酸亚铁、三氯化铁中选出PAC和Al2(SO4)3,然后针对这两种絮凝剂,研究确定其最佳絮凝条件及最大去除率。PAC的最佳实验条件为:投加量为1.6 g/L,pH=6,快速搅拌时间为30 s,沉降时间为30 min;Al2(SO4)3的最佳实验条件为:投加量为1 g/L,原水pH=6,快速搅拌时间为90 s,沉降时间为30 min。絮凝效果为:COD去除率分别为82.3%和75.38%,色度去除率都达到了90%以上。     

修井作业现场3G网络视频监控系统的研究

目前油田修井作业现场生产方式存在信息不畅通的问题,无法实时跟踪监控井场安全生产运行情况和设备安全运转情况。研究应用"修井作业现场3G网络视频监控系统",能很好的解决作业现场视频信息及时交换问题,较好的解决了较偏远的作业队督查、监控问题,提高油田修井作业现场安全管理和应急管理水平。     

三表学生复变函数课程教学的尝试

在数学教学中,认知固然重要,但情感因素对学习者的影响也不可忽视。积极的情感因素可以激发学生的学习兴趣,从而提高学习成绩。     

浅谈新技术在地籍测绘中的应用

随着测绘科技的进步和现代技术的发展,信息技术日新月异,各领域的新技术层出不穷。在地籍测绘领域中,新技术和设备也在不断更新,随着GIS、RS、GPS(RTK)等技术的不断发展,对促进地籍测绘技术的进步和跨越式发展具有十分重要的意义和作用,这为地籍测绘领域的发展和进步作出巨大的贡献。     

Optimal size, optimal timing and optimal financing of an investment

Corporate investment is an important determinant of economic well-being. The existing literature identifies optimal investment size and timing without the possibility of debt financing, as well as the effect of debt financing on investment timing without the option to choose investment size. This paper contributes to the literature by identifying the optimal size, optimal timing and optimal financing for an investment when the firm controls all three decisions (as it usually does in practice). The investment size and investment trigger are generally positively related: when investment is delayed (accelerated) it is larger (smaller) in size, thus the overall effect on investment is ambiguous. However, when tax rate or bankruptcy cost is increased, the trigger rises and size falls, hence the effect on investment is unambiguously negative. The effect of debt financing on investment depends on the amount of debt used; with the optimal amount of debt, investment is delayed relative to the no-debt case, and this delay can be economically significant; however, the investment, when eventually made, will be larger in size. Overall, it is not appropriate to ignore either the firm’s ability to choose investment size or its option to use debt financing, when modeling the investment decision.     

What does it mean to find the face of the franchise? Physical attractiveness and the evaluation of athletic performance

We show that attractiveness, as measured by facial symmetry, leads to greater rewards in professional sports. National Football League quarterbacks who are more attractive are paid greater salaries and this premium persists after controlling for player performance.