Retaliatory temporary trade barriers: New facts and patterns

This paper takes a fresh look into the role of Temporary Trade Barriers (TTBs) and whether they are introduced for strategic reasons. We construct a novel sectoral measure of retaliation using daily bilateral data on TTB responses in 1220 subsectors across a panel of 25 advanced and emerging economies over 1989–2015. We use this measure to present novel stylized facts and patterns suggesting that strategic considerations may be more important (in terms of intensity and frequency) than commonly understood from the existing literature, which has tended to ignore within-year responses. Our evidence indicates that retaliation actually often consists of responses across many sectors and indeed that same-sector retaliation is far from being the norm.     

Bayesian Estimation for Quantification by Real-time Polymerase Chain Reaction Under a Branching Process Model of the DNA Molecules Amplification Process

The aim of Quantitative Polymerase Chain Reaction is to determine the initial amount X ₀ of specific nucleic acids from an observed trajectory of the amplification process, the amplification being achieved through successive replication cycles. This process depends on the efficiency {p _n } _n of replication of the DNA molecules, p _n being the probability that a molecule will duplicate at replication cycle n. Assuming p _n  = p for all n, Bayesian estimators of the unknown parameter θ = (p, X ₀) are constructed by Markov Chain Monte Carlo methods under a Bienaymé-Galton-Watson branching model of the amplification process. The Bayesian approach takes into account some prior information on the parameter. Relying on simulated data, the proposed Bayesian estimators and their credibility sets are shown to be quite accurate.     

UNEMPLOYMENT INSURANCE IN WELFARE STATES: THE IMPACTS OF SOFT DURATION CONSTRAINTS

Abstract Based on a major reform of Norwegian unemployment insurance (UI), we examine the behavioral impacts of soft and hard UI duration constraints. A constraint is interpreted as hard if a claimant cannot rely on any form of income support after exhaustion, and as soft if UI is replaced by follow‐on benefits or participation in active labor market programs (ALMP). We find that both hard and soft constraints raise the job hazard significantly, with surprisingly similar spikes at UI exhaustion. Participation in ALMP raises the probability of eventually finding a job, but at the cost of lengthening the overall job‐search period.     

DO IMMIGRANTS CAUSE CRIME?

We examine the empirical relationship between immigration and crime across Italian provinces during the period 1990–2003. Drawing on police administrative records, we first document that the size of the immigrant population is positively correlated with the incidence of property crimes and with the overall crime rate. Then, we use instrumental variables based on immigration toward destination countries other than Italy to identify the causal impact of exogenous changes in Italy’s immigrant population. According to these estimates, immigration increases only the incidence of robberies, while leaving unaffected all other types of crime. Since robberies represent a very minor fraction of all criminal offenses, the effect on the overall crime rate is not significantly different from zero.     

封头拉伸工艺中常见缺陷及原因分析

对YSP-15型钢瓶上下封头拉伸工艺中常见的缺陷进行分析,提出了控制封头在拉伸中产生缺陷的主要措施.     

A note on replacement policy comparisons from NBUC lifetime of the unit

Age and block replacement policies are commonly used in order to reduce the number of in-service failures when the systems are functioning indefinitely. In reliability theory, the lifetime of a system can be modeled by means of the NBUC aging class that is characterized throughout comparisons of the residual lives in the sense of the icx order. The purpose of this paper is to establish stochastic comparisons between the age (block) replacement policy and a renewal process with no planned replacements when the lifetime of the unit is NBUC. Supported by Ministerio de Ciencia y Tecnología under grant BFM2000-0362     

A method for screening active effects in supersaturated designs

A supersaturated design (SSD) is a design whose run size is not enough for estimating all the main effects. The goal in conducting such a design is to identify, presumably only a few, relatively dominant active effects with a cost as low as possible. However, data analysis of such designs remains primitive: traditional approaches are not appropriate in such a situation and several methods which were proposed in the literature in recent years are effective when used to analyze two-level SSDs. In this paper, we introduce a variable selection procedure, called the PLSVS method, to screen active effects in mixed-level SSDs based on the variable importance in projection which is an important concept in the partial least-squares regression. Simulation studies show that this procedure is effective.     

FAST DOUBLE BOOTSTRAP TESTS OF NONNESTED LINEAR REGRESSION MODELS

It has been shown in previous work that bootstrapping the J test for nonnested linear regression models dramatically improves its finite-sample performance. We provide evidence that a more sophisticated bootstrap procedure, which we call the fast double bootstrap, produces a very substantial further improvement in cases where the ordinary bootstrap does not work as well as it might. This FDB procedure is only about twice as expensive as the usual single bootstrap.     

Extremal limit theorems for observations separated by random power law waiting times

This paper develops extreme value theory for random observations separated by random waiting times whose exceedence probability falls off like a power law. In the case where the waiting times between observations have an infinite mean, a limit theorem is established, where the limit is comprised of an extremal process whose time index is randomized according to the non-Markovian hitting time process for a stable subordinator. The resulting limit distributions are shown to be solutions of fractional differential equations, where the order of the fractional time derivative coincides with the power law index of the waiting time. The probability that the limit process remains below a threshold is also computed. For waiting times with finite mean but infinite variance, a two-scale argument yields a fundamentally different limit process. The resulting limit is an extremal process whose time index is randomized according to the first passage time of a positively skewed stable Lévy motion with positive drift. This two-scale limit provides a second-order correction to the usual limit behavior.     

Stochastic comparisons of multivariate frailty models

A multivariate frailty model in which survival function depends on baseline distributions of components and the frailty random variable is considered. Since misspecification in choice of frailty distribution and/or baseline distribution may affect the distribution of multivariate frailty model, using theory of stochastic orders, we compare multivariate frailty models arising from different choices of frailty distribution.