Long-Run Identification in a Fractionally Integrated System

We propose an extension of structural fractionally integrated vector autoregressive models that avoids certain undesirable effects on the impulse responses that occur if long-run identification restrictions are imposed. We derive the model’s Granger representation and investigate the effects of long-run restrictions. Simulations illustrate that enforcing integer integration orders can have severe consequences for impulse responses. In a system of U.S. real output and aggregate prices, the effects of structural shocks strongly depend on the specification of the integration orders. In the statistically preferred fractional model, shocks that are typically interpreted as demand disturbances have a very brief influence on GDP. Supplementary materials for this article are available online.     

Flexible Latent‐State Modelling of Old Faithful's Eruption Inter‐Arrival Times in 2009

This paper is concerned with the analysis of a time series comprising the eruption inter‐arrival times of the Old Faithful geyser in 2009. The series is much longer than other well‐documented ones and thus gives a more comprehensive insight into the dynamics of the geyser. Basic hidden Markov models with gamma state‐dependent distributions and several extensions are implemented. In order to better capture the stochastic dynamics exhibited by Old Faithful, the different non‐standard models under consideration seek to increase the flexibility of the basic models in various ways: (i) by allowing non‐geometric distributions for the times spent in the different states; (ii) by increasing the memory of the underlying Markov chain, with or without assuming additional structure implied by mixture transition distribution models; and (iii) by incorporating feedback from the observation process on the latent process. In each case it is shown how the likelihood can be formulated as a matrix product which can be conveniently maximized numerically.     

Three estimators for the poisson regression model with measurement errors

We consider two consistent estimators for the parameters of the linear predictor in the Poisson regression model, where the covariate is measured with errors. The measurement errors are assumed to be normally distributed with known error variance σ _u ² . The SQS estimator, based on a conditional mean-variance model, takes the distribution of the latent covariate into account, and this is here assumed to be a normal distribution. The CS estimator, based on a corrected score function, does not use the distribution of the latent covariate. Nevertheless, for small σ _u ² , both estimators have identical asymptotic covariance matrices up to the order of σ _u ² . We also compare the consistent estimators to the naive estimator, which is based on replacing the latent covariate with its (erroneously) measured counterpart. The naive estimator is biased, but has a smaller covariance matrix than the consistent estimators (at least up to the order of σ _u ² ).     

A return to work program for injured workers: a reassignment model

The current workers' compensation system does not encourage permanently restricted workers who are disabled due to work related injuries to return to work. Workers are often labeled permanently disabled and are released from their positions with their employers. However, according to the Americans with Disabilities Act of 1990, these individuals may be qualified to return to productive employment. This paper will describe a Reassignment Model for occupational therapy supported by the rehabilitation frame of reference. This Model presents reassignment to a vacant position as a reasonable accommodation to return injured workers to productive employment. A case study will illustrate the successful implementation of the model. The potential benefits of using this Model will be described for clients, society, employers, and the occupational therapy profession.     

Success of research-based spin-offs. State-of-the-art and guidelines for further research

The topic of this paper is research-based spin-offs from public organisations. The initial point is a discussion about the economic benefit of such companies. The paper investigates factors influencing the generation, development, and growth of research-based spin-offs built on scientific know-how or research results. An analysis of previous empirical studies allows the identification of three main groups of success factors, concerning the founder, the environment, and the later company itself. Based on Gartner’s framework of new venture creation—used as a structure-building tool and substitute of entrepreneurial theory—we give an overview of entrepreneurial success factors. We also identify inconsistencies and gaps in empirical evidence and guidelines for further research. Particular explanation seems to be necessary for incentives, ideas, and incubation environments, all having an impact on formation and performance of spin-offs.      

Dysfunctional Transactions and Therapeutic Functions: An Evolutive Model

The present study is a result of an interdisciplinary team's work, where a physicist, a family therapist and a developmental psychologist try to share their knowledge and epistemologies. In this kind of conflictual companionship, models of one discipline are tentatively applied to another. This doesn't imply that the different disciplines are isomorphic, but it provides for unusual frames of reference: questions, possibly essential ones, are reformulated in a new language, or in a perspective which was not accessible within the conceptual framework developed for one particular discipline. Our experience is that this kind of effort, in itself a provocative learning experience, is also conducive to original tentative answers in all disciplines involved. Be they of theoretical or experimental nature, it is then up to the specialists of these disciplines to validate the evolved propositions in terms of their own categories.     

In the mood for obedience: Despair,cynicism, and seduction among employment service employees

Based on an ethnography at the Swedish Public Employment Service, this paper offers a typology of how employees managed to obey tasks they would rather not perform. It is argued that earlier studies of workplace obedience have tended to focus on a single mood in which the actor obeys: despair, cynicism, or seduction. Here, the movement between these moods is analysed. To pass from despair to cynicism, the emotional sensitivity particular to despair must be reduced. This happens through processes of detachment. To pass from cynicism to seduction, employees must break down the reflexive layer that obstructs enthusiasm. This happens through positive thinking. The reflexive step back to cynicism requires an analytic space that can be obtained either intentionally or through certain events. Building up the sensitivity that distinguishes cynicism from despair occurs through forms of alarm.     

THE POLITICAL ECONOMICS OF THE ARAB SPRING

There were large differences in the responses of Arab dictators to the Arab Spring protests. To understand these differences, I present a stylized model of how a dictator responds to mass protests for democratization in a polarized country with two ethnic or religious groups. In this model, the dictator's response crucially depends on oil revenues and his affiliation to either the majority or the minority group. I document that the model's predictions are consistent with the observed differences in the Arab dictators' responses. Hence, ethnic politics and religious divides may play an important role in political transitions and regime changes. (JEL D72, D74)