Las decisiones de empleo y salarios de cooperativas de trabajo y empresas capitalistas : evidencia para Uruguay en base a datos de panel

The following article presents new econometric evidence on comparative behavior between worker cooperatives and capitalist firms, identifying differences in wage and employment responses. We exploit a comprehensive panel data set that covers the universe of cooperatives and their capitalist counterparts registered in social security records in Uruguay from April 1996 to December 2005. The analysis of employment and wage evolution in both types of enterprises suggests that there may be different mechanisms of adjustment to idiosyncratic price changes and macroeconomic shocks. The data set also allows us to estimate wages and employment variations for cooperative’s members and employees separately. The results of the comparison are analyzed in the light of theoretical explanations and institutional characteristics of the cooperatives’ development in Uruguay. Our findings are broadly consistent with previous studies for Italian and plywood northwest U.S. cooperatives. The importance of this research owes to the fact that comparative empirical studies of this kind are in general rare, particularly for developing countries.capitalist firms, worker cooperatives, employment, wages

Los objetivos de una empresa gestionada por sus trabajadores : un análisis sobre el caso uruguayo

The theoretical discussion concerning the comparison of employment and wage decisions between capitalist firms and worker cooperatives began with the seminal work of Ward (1958). The model assumes that worker cooperatives maximizes the net income per member instead of total profits. Even though it has been largely criticized, the Ward model has dominated the theoretical literature on worker coops. For instance, some authors have argued that worker coops are not only concerned about income per worker but also employment levels. However, the empirical content of these competing theoretical models has been rarely analyzed. In this article, following the methodology proposed by Craig and Pencavel (1993), we estimate the parameters of a generic objective function. These parameters determine the relative importance that worker coops place on income per worker vis-a-vis the level of employment. The study is based a long micro-panel of Uruguayan firms containing the entire population of worker coops and conventional firms in 31 3-digit sectors. Our results support the view that worker coops pursue mixed objectives, including both employment and income per worker.capitalist firms, worker cooperatives, firm objectives

Time fractals and discrete scale invariance with trapped ions

We show that a one-dimensional chain of trapped ions can be engineered to produce a quantum mechanical system with discrete scale invariance and fractal-like time dependence. By discrete scale invariance we mean a system that replicates itself under a rescaling of distance for some scale factor, and a time fractal is a signal that is invariant under the rescaling of time. These features are reminiscent of the Efimov effect, which has been predicted and observed in bound states of three-body systems. We demonstrate that discrete scale invariance in the trapped ion system can be controlled with two independently tunable parameters. We also discuss the extension to n-body states where the discrete scaling symmetry has an exotic heterogeneous structure. The results we present can be realized using currently available technologies developed for trapped ion quantum systems.Comment: 4 + 5 pages (main + supplemental materials), 2 + 3 figures (main + supplemental materials), version to appear in Physical Review A Rapid Communication

Ecosystem sentinels for climate change? Evidence of wetland cover changes over the last 30 years in the tropical Andes

While the impacts of climate change on individual species and communities have been well documented there is little evidence on climate-mediated changes for entire ecosystems. Pristine alpine environments can provide unique insights into natural, physical and ecological response to climate change yet broad scale and long-term studies on these potential ‘ecosystem sentinels’ are scarce. We addressed this issue by examining cover changes of 1689 high-elevation wetlands (temporarily or perennial water-saturated grounds) in the Bolivian Cordillera Real, a region that has experienced significant warming and glacier melting over the last 30 years. We combined high spatial resolution satellite images from PLEIADES with the long-term images archive from LANDSAT to 1) examine environmental factors (e.g., glacier cover, wetland and watershed size) that affected wetland cover changes, and 2) identify wetlands’ features that affect their vulnerability (using habitat drying as a proxy) in the face of climate change. Over the (1984–2011) period, our data showed an increasing trend in the mean wetland total area and number, mainly related to the appearance of wet grassland patches during the wetter years. Wetland cover also showed high inter-annual variability and their area for a given year was positively correlated to precipitation intensities in the three months prior to the image date. Also, round wetlands located in highly glacierized catchments were less prone to drying, while relatively small wetlands with irregularly shaped contours suffered the highest rates of drying over the last three decades. High Andean wetlands can therefore be considered as ecosystem sentinels for climate change, as they seem sensitive to glacier melting. Beyond the specific focus of this study, our work illustrates how satellite-based monitoring of ecosystem sentinels can help filling the lack of information on the ecological consequences of current and changing climate conditions, a common and crucial issue especially in less-develope