Devaluation expectations and the unit root hypothesis: The Italian Lira in the European monetary system

Summary In several studies the unit root hypothesis of EMS exchange rates is analysed within the context of devaluation expectations estimation. By means of bootstrap inference it is shown that these procedures are not compatible with standard Dickey-Fuller significance levels and may lead to a wrong rejection of the null hypothesis. In the case of the Italian Lira/Deutsche Mark exchange rate, the hypothesis of a unit root is not rejected and expectations can be modelled by means of a reflected Brownian motion. The estimated devaluation expectations are related with some macro variables which provide evidence for the structure of expectations. This research has been partially supported with 40% and 60% MURST grants. The author wishes to thank the Bank of Italy for the exchange rates and the interest rates data and Ulf S?derstr?m for providing macroeconomic indicators. Useful suggestions from Riccardo Cesari, Michele Costa and two anonymous referees are gratefully acknowledged.     

Threshold Autoregression with a Unit Root

This paper develops an asymptotic theory of inference for an unrestricted two‐regime threshold autoregressive (TAR) model with an autoregressive unit root. We find that the asymptotic null distribution of Wald tests for a threshold are nonstandard and different from the stationary case, and suggest basing inference on a bootstrap approximation. We also study the asymptotic null distributions of tests for an autoregressive unit root, and find that they are nonstandard and dependent on the presence of a threshold effect. We propose both asymptotic and bootstrap‐based tests. These tests and distribution theory allow for the joint consideration of nonlinearity (thresholds) and nonstationary (unit roots). Our limit theory is based on a new set of tools that combine unit root asymptotics with empirical process methods. We work with a particular two‐parameter empirical process that converges weakly to a two‐parameter Brownian motion. Our limit distributions involve stochastic integrals with respect to this two‐parameter process. This theory is entirely new and may find applications in other contexts. We illustrate the methods with an application to the U.S. monthly unemployment rate. We find strong evidence of a threshold effect. The point estimates suggest that the threshold effect is in the short‐run dynamics, rather than in the dominate root. While the conventional ADF test for a unit root is insignificant, our TAR unit root tests are arguably significant. The evidence is quite strong that the unemployment rate is not a unit root process, and there is considerable evidence that the series is a stationary TAR process.     

Advancing careers through ‘merit’: a rationalized-sensemaking narrative in hierarchical organizations

ABSTRACT

This contribution provides an in-context exploration of how middle-managers make sense of their career progress, and particularly focuses on ‘merit’ to understand how careers are driven in a hierarchical organization. The study exposes ‘merit’ as a fragmented and individualized construction that links back to the participants’ broader life ambitions and identity footprint. It also shows a tendency for maintaining trust in ‘merit’ above other circumstantial and opportunity factors, even in face of events which undermine the application of the merit-based principle. ‘Merit’ is hence portrayed to be a rationalized narrative in careers’ trajectory; a marker used by participants to make sense of events in a coherent manner, consequently experiencing self-efficacy and reducing uncertainty. The findings add complexity to the ‘meritocracy’ debate, calling for new critiques which address its underlying inequality dimension while also contemplating the individual psychological purpose driving ‘merit’ beliefs.     

语言相对论研究述评

从时间、色彩、位值与运动事件等四个方面介绍与述评国外近期对萨丕尔．沃尔夫假说的实证研究，同时结合国内一些学者的成果，来探讨语言与思维之间的关系。     

高度层优化使用问题的指派模型及算法

飞行高度层的优化使用是空中交通管制(ATC)自动化理论研究的核心问题。为取得任意两架飞机之间的水平约束,提出航空器相对于飞行高度层的一般性指派问题(AP)的研究方法。引入广义指派(GAP)扩展效率矩阵,分析单架飞机占用一个飞行高度层和多机共用一层效率矩阵元素的定义方法,研究垂直剖面航迹优化的匈牙利求解。效率矩阵如果随条件发生变化,问题变为不确定型,对此,给出了将其转换成确定型问题处理的一般方法。实例表明,直接或间接应用匈牙利算法对于ATC决策的实时求解是有效的。     

有关椭球面轨迹问题的研究

对有关椭球面的轨迹问题作了研究,得出了两个重要的定理。     

一种快速全局运动估计算法

为了对全局运动进行准确快速的估计,在对全局运动估计算法进行研究的基础上,提出了一种快速全局运动估计算法。该算法基于非线性密度估计,采用了六参数的仿射模型。为了提高计算速度,采用了3层金字塔进行多分辨率计算,而且在每层迭代计算中,将基于块的外点去除算法与特征点提取算法相结合,这样既加快了算法的速度,又提高了计算结果的准确性。全局运动估计的实验结果表明,该算法在速度和准确性上具有一定的优势。     

液压设备的固体污染分析及防治措施

液压系统中的固态杂质,是污染油液的主要原因,也是液压泵和液压马达效率降低,液压阀卡死,噪声和振动等现象发生的主要原因。因此,固体污染物分析与控制的研究具有积极而重要的意义。     

Trajectory of quality of mother-child interactions: Prospective links with child socioemotional functioning

Research shows that the quality of mother-child interactions is a robust antecedent of child socioemotional functioning. Yet, relatively little is known about the evolution of this relational quality over time, and even less about how changes in relational quality may bear on child adjustment. This study aimed to describe the trajectory of quality of mother-child interactions between ages 2 and 7 and to investigate associations between individual differences in this trajectory and child socioemotional functioning at age 8. In a sample of 233 mother-child dyads primarily comprised of White French-Canadian mothers, the quality of interactions was assessed during 10-min play sequences when children were aged 2, 4, and 7 years. Child internalizing, externalizing, and prosocial behaviors were reported by a subsample of 171 teachers at age 8. The results showed that on average, quality of mother-child interactions decreased over time. In terms of individual differences, children who experienced a slower decrease in the quality of interactions with their mother from 2 to 7 years showed less internalizing behavior at age 8, over and above initial quality at 2 years. Children involved in higher quality interactions with their mother at 2 years showed more prosocial and less externalizing behavior at age 8, independent of the subsequent decrease in the quality of those interactions. The findings suggest that initial levels and subsequent changes in the quality of mother-child interactions are two distinct indicators of their relationship with potentially different implications for child adjustment.     

恒有与无常:佛教运动观探析——以说一切有部为中心

说一切有部作为部派佛教中成立较早的学派,其"三世恒有,法体恒存"的宗义代表了佛教运动观的早期理论形态。有部的宗义发源于对原始佛教经典中法相的相摄、自相、共相等关系的研究,而具有其独特的论证方式和理论内涵。由"无常"而推出"恒有",以"恒有"来论证"无常",是有部对动静辩证关系的独特理解。有部运动观独特的思维方式与理论论证模式被后来的大乘佛教所继承和发展。从原始佛教的"诸行无常",到说一切有部的"法体恒有",再到大乘中观学的非断非常、动静双遣,反映了佛教运动观的辩证发展过程。