Services inflation dynamics and persistence puzzle in Brazil: a time-varying parameter approach

This article analyses services inflation dynamics in Brazil, focusing on the Services Inflation Persistence Puzzle, for monthly data from January 2004 to February 2016. We apply a time-varying parameter (TVP) approach, via a Kalman filter, to estimate hybrid Phillips curves and compare inflation inertia for tradable goods and services inflation. Aggregate Brazilian Extended Consumer Price Index inflation serves as a benchmark. To justify the TVP analysis, parameter instability and structural change tests are implemented, based on OLS and Generalized Method of Moments (GMM) frameworks. The main results are as follows: (i) the TVP approach is relevant due to observed instability in some parameters estimated; (ii) inflation expectation coefficients are higher than lagged inflation in all calculations, but inflation inertia is not negligible at all; (iii) services inflation persistence ranges from 27 to 36%, whereas tradable goods inflation persistence ranges from 36 to 47%, providing evidence of the Services Inflation Persistence Puzzle in Brazil; (iv) from 2009 onwards an increase in one percentage point in real wages raises monthly services inflation rate by 0.02 to 0.03 percentage point; (v) there is evidence that cost-push pressures, due to wage increases in the service sector, are more important to explain services inflation than demand pressures from early 2009 to mid-2014.     

Is there a role for uncertainty in forecasting output growth in OECD countries? Evidence from a time-varying parameter-panel vector autoregressive model

This paper uses a time-varying parameter-panel vector autoregressive (TVP-PVAR) model to analyze the role played by domestic and US news-based measures of uncertainty in forecasting the growth of industrial production of 12 Organisation for Economic Co-operation and Development (OECD) countries. Based on a monthly out-of-sample period of 2009:06 to 2017:05, given an in-sample of 2003:03 to 2009:05, there are only 46% of cases where domestic uncertainty can improve the forecast of output growth relative to a baseline monetary TVP-PVAR model, which includes inflation, interest rate and nominal exchange rate growth, besides output growth. Moreover, including US uncertainty does not necessarily improve the forecasting performance of output growth from the TVP-PVAR model which includes only the domestic uncertainty along with the baseline variables. So, in general, while uncertainty is important in predicting the future path of output growth in the 12 advanced economies considered, a forecaster can do better in majority of the instances by just considering the information from standard macroeconomic variables.     

中美制造业双边贸易对美国相对工资差距的影响研究*

在新古典贸易理论一般均衡的框架之下,运用1997-2014年中美两国的投入产出、贸易和工资数据,本文定量考察了中美制造业产品的双边贸易同美国制造业相对工资差距的关系。结果发现,美国从中国的净进口对美国制造业非熟练劳动力和熟练劳动力相对工资差距扩大存在影响,但影响幅度较小,贸易并不是引起相对收入差距扩大的唯一原因。但随着中美双边制造业贸易的进一步发展,美中贸易对美国工资差距的影响可能越来越大,以保护非熟练劳动力为名对中国产品实施贸易限制的呼声将会更高。     

Informal pay gaps in good and bad times: Evidence from Russia

Informal work is traditionally large in Russia and has further increased in the recent years. We explore the implications of this shift in terms of wage dynamics. Our characterization is based on the estimation of informal pay gaps at the mean and along the wage distribution, relying on the Russian Longitudinal Monitoring Survey for 2003–2017. Our approach comprises three original features: we rely on unconditional quantile effects of informality, we incorporate quantile-specific fixed effects using a tractable approach, and we suggest a treatment of the incidental parameter bias. Over the whole period, informal wage penalties are relatively small and do not suggest heavily segmented labor markets, even at low wage levels. Yet, in the past decade, a substantial negative selection into informal employment and self-employment has taken place, on average and especially at low earnings. Economic downturns and labor market policies have likely contributed to the shakeout of less productive workers in the formal sector, making the low-tier informal sector more of a last resort.     

大型灯泡贯流式水轮发电机组定子铁损试验及参数选择

广西桥巩水电站发电机组定子铁芯组装工作在现场进行,根据国家规程规范规定,对现场叠压装配的定子铁芯进行铁芯损耗试验,通过铁损试验检查定子铁芯压紧螺栓的压紧情况和发现铁芯局部发热的故障点及绝缘性能。本次试验通过对定子铁损试验接线方式择优选择、试验参数合理的计算和试验结果详细的分析,使试验误差降低到最小值,单位铁芯损耗值等各项指标均优于国家或厂家的标准值,为电站今后定子检修提供参考。     

Auto CAD在铸造工艺中的应用

铸造领域与计算机辅助设计技术结合不断发展及Auto CAD的不断改良,使得Auto CAD功能更加强大。文章介绍Auto CAD技术在铸造工艺设计中的应用,综合评述了铸造工艺Auto CAD研究的内容和现状,以及如何利用Auto CAD来完成铸造的过程。     

锚杆支护“三径”匹配的研究

锚杆支护因具有技术先进、经济合理、安全可靠等优点,而被许多煤矿广泛地推广应用,但有时也存在设计不合理、支护强度大、支护费用高,或支护强度不足,安全性差的情况。文章通过对"三径"匹配的研究,提出了合理匹配方案,为描杆支护提供了借鉴。     

球罐焊接后热处理对残余应力的影响

球罐容积大、壳体壁厚、球壳板刚度较大,在组装过程中不可避免地产生较大的组装与焊接残余应力和变形,因而球罐焊后整体热处理对其安全使用尤为重要。本文采用SYSWELD工程有限元分析软件中的热处理工具,结合实际的热处理规范要求,加载焊接后模型的温度场和残余应力场状态,以达到对焊后热处理的真实模拟。为研究焊后热处理工艺对减小焊接残余应力的意义提供理论指导。     

二项式系列题目类解初探

二次函数是中学数学的重要内容之一,和它相关的内容,如:二次方程、二次不等式、二次三项式及二次函数的图像,构成了一个体系,称之为"二次式系列";本文主要在以下三个方面对这些题目的解法进行探讨:(一)求参数的范围;(二)根的存在情况的判别;(三)求最大、最小值;通过以上的讨论,以期提高中学生对此类题目的解题方法和解题技巧。     

某型末制导炮弹惯导段弹道对气动参数灵敏度分析

目前的灵敏度分析往往需要依赖于某种寻优算法,并要求目标函数能求取偏导数。而末制导炮弹左右舵片上的控制力是突变的,无法对其求取偏导数。为解决这个问题并保证灵敏度分析精度,本文提出用解析法与有限差分法法有机结合的方法对气动参数进行灵敏度分析。结果表明,该方法能很好的解决了该弹道灵敏度分析问题,且分析速度快、精度高。