Tough Policies, Incredible Policies?

We revisit the question of what determines the credibility of macroeconomic policies here, of promises to repay public debt. Almost all thinking on the issue has focused on governments' strategic decision to default (or erode the value of outstanding debt via inflation/devaluation). But sometimes governments default not because they want to, but because they cannot avoid it: adverse shocks leave them no option. We build a model in which default/devaluation can occur deliberately (for strategic reasons) or unavoidably. If such unavoidable fiscal crises a) have pecuniary costs and b) occur with possible probability, much conventional wisdom on the determinantes of credibility need no longer hold. For instance, appointing a conservative policymaker or denominating public debt in foreign currency may reduce, not increase, credibility.

Historiografía y ciencia social actual en el análisis de políticas públicas en Chile desde 1990 : Una aproximación para enmarcar el estudio del proceso de reforma educativa de la transición a la democracia

El estudio de las políticas públicas, nos dice Celina Souza, surgió como un subtema de las ciencias políticas en Estados Unidos (Souza, Traducción propia, p. 22). Si bien esta disciplina ha dado varias definiciones acerca de lo que es una política pública, en todas ellas (i) se requiere de la acción (o, en negativo, inacción) de algún o algunos agentes investidos de autoridad pública, generalmente el gobierno; (ii) se supone una visión en la que el poder político está configurado antes que como una estructura estable y determinativa, como una de tipo flexible y a determinar; (iii) se supone la intervención de múltiples actores, vinculados tanto al mundo político como al social, empresarial y gremial, los que pugnan o comparten el espacio público en cuestión, y (iv) se supone la existencia de un problema o tema específico a abordar. Así vistas las cosas, no resulta extraño que el análisis de cientistas políticos y de sociólogos tengan una matriz teórica compartida al momento de analizar las políticas públicas de los gobiernos democráticos acaecidos tras el fin de la dictadura.Mesa 18: El Estado como problema y solución: Estado, administración y políticas públicas.Facultad de Humanidades y Ciencias de la Educació

Exit, Voice, Loyalty and Neglect as Student Responses to Dissatisfaction: An Act Frequency Approach

An important task in higher education is the provision of an abstract theoretical model capable of integrating various student responses to dissatisfaction. Drawing upon recent work in the social sciences, we propose exit, voice, loyalty and neglect (EVLN) as a parsimonious means of understanding the relationships among the different responses to dissatisfaction. We use an act frequency approach to develop and validate the EVLN constructs as a preliminary first step toward future predictive theory.La définition d'un modèle théorique abstrait capable d'intégrer les différentes réactions de mécontentement des étudiants est une tâche importante dans le domaine de l'enseignement supérieur. En nous appuyant sur des recherches récentes en sciences sociales, nous proposons "sortie, voix, loyauté et manque d'attention" comme moyen parcimonieux pour comprendre les relations entre les différentes réactions de mécontentement. Nous utilisons une approche de fréquence d'actions pour élaborer et valider les concepts de "sortie, voix, loyauté et manque d'attention", ce qui constitue un premier pas vers une théorie prédictive future

Target-oriented least-squares reverse-time migration using Marchenko double-focusing: reducing the artifacts caused by overburden multiples

Geophysicists have widely used Least-squares reverse-time migration (LSRTM) to obtain high-resolution images of the subsurface. However, LSRTM needs an accurate velocity model similar to other migration methods. Otherwise, it suffers from depth estimation errors and out of focus images. Moreover, LSRTM is computationally expensive and it can suffer from multiple reflections. Recently, a target-oriented approach to LSRTM has been proposed, which focuses the wavefield above the target of interest. Remarkably, this approach can be helpful for imaging below complex overburdens and subsalt domains. Moreover, this approach can significantly reduce the computational burden of the problem by limiting the computational domain to a smaller area. Nevertheless, target-oriented LSRTM still needs an accurate velocity model of the overburden to focus the wavefield accurately and predict internal multiple reflections correctly. In recent years, Marchenko redatuming has emerged as a novel data-driven method that can predict Green's functions at any arbitrary depth, including all orders of multiples. The only requirement for this method is a smooth background velocity model of the overburden. Moreover, with Marchenko double-focusing, one can make virtual sources and receivers at a boundary above the target and bypass the overburden. This paper proposes a new algorithm for target-oriented LSRTM, which fits the double-focused data with modeled data at a boundary above the target of interest. Consequently, our target-oriented LSRTM algorithm correctly accounts for all orders of overburden-related multiples, resulting in a significant reduction of the artifacts caused by overburden internal multiple reflections in the target image compared to conventional LSRTM.Comment: This preprint is submitted to Geophysical Journal International and is under review as of this momen

Target-Enclosed Least-Squares Seismic Imaging

Least-Squares Reverse-Time Migration (LSRTM) is a method that seismologists utilize to compute a high-resolution subsurface image. Nevertheless, LSRTM is a computationally demanding problem. One way to reduce the computational costs of the LSRTM is to choose a small region of interest and compute the image of that region. However, finding representations that account for the wavefields entering the target region from the surrounding boundaries is necessary. This paper confines the region of interest between two boundaries above and below this region. The acoustic reciprocity theorem is employed to derive representations for the wavefields at the upper and lower boundaries of the target region. With the help of these representations, a target-enclosed LSRTM algorithm is developed to compute a high-resolution image of the region of interest. Moreover, the possibility of using virtual receivers created by Marchenko redatuming is investigated

Target-oriented least-squares reverse-time migration with Marchenko redatuming and double-focusing: Field data application

Recently, the focus of reflection seismologists has shifted to applications where a high-resolution image of the subsurface is required. Least-Squares Reverse-Time Migration (LSRTM) is a common tool used to compute such images. Still, its high computational costs have led seismologists to use target-oriented LSRTM for imaging only a small target of interest within a larger subsurface block. Redatuming the data to the upper boundary of the target of interest is one approach to target-oriented LSRTM. Still, many redatuming methods cannot account for multiple scatterings within the overburden. This paper presents a target-oriented least-squares reverse time migration algorithm which integrates Marchenko redatuming and double-focusing. This special redatuming method accounts for all orders of multiple scattering in the overburden for target-oriented LSRTM. Additionally, the paper demonstrates that a double-focusing algorithm can further reduce the size of the data by reducing both spatial and temporal dimensions. This algorithm is applied to field data acquired in the Norwegian Sea.Comment: This preprint has been submitted to Geophysics journal for peer-revie