Estimating Trade Elasticities: Demand Composition and the Trade Collapse of 2008-09

This paper introduces a new methodology for the estimation of demand trade elasticities based on an import intensity-adjusted measure of aggregate demand, with the foundation of a stylized theoretical model. We compute the import intensity of demand components by using the OECD Input-Output tables. We argue that the composition of demand plays a key role in trade dynamics because of the large movements in the most import-intensive categories of expenditure (especially investment, but also exports). We provide evidence in favor of these mechanisms for a panel of 18 OECD countries, paying particular attention to the 2008-09 Great Trade Collapse.

Optical trapping and critical Casimir forces

Critical Casimir forces emerge between objects, such as colloidal particles, whenever their surfaces spatially confine the fluctuations of the order parameter of a critical liquid used as a solvent. These forces act at short but microscopically large distances between these objects, reaching often hundreds of nanometers. Keeping colloids at such distances is a major experimental challenge, which can be addressed by the means of optical tweezers. Here, we review how optical tweezers have been successfully used to quantitatively study critical Casimir forces acting on particles in suspensions. As we will see, the use of optical tweezers to experimentally study critical Casimir forces can play a crucial role in developing nano-technologies, representing an innovative way to realize self-assembled devices at the nano- and microscale.Comment: 18 pages, 11 figure

Potential of ALOS2 and NDVI to estimate forest above-ground biomass, and comparison with lidar-derived estimates

Remote sensing supports carbon estimation, allowing the upscaling of field measurements to large extents. Lidar is considered the premier instrument to estimate above ground biomass, but data are expensive and collected on-demand, with limited spatial and temporal coverage. The previous JERS and ALOS SAR satellites data were extensively employed to model forest biomass, with literature suggesting signal saturation at low-moderate biomass values, and an influence of plot size on estimates accuracy. The ALOS2 continuity mission since May 2014 produces data with improved features with respect to the former ALOS, such as increased spatial resolution and reduced revisit time. We used ALOS2 backscatter data, testing also the integration with additional features (SAR textures and NDVI from Landsat 8 data) together with ground truth, to model and map above ground biomass in two mixed forest sites: Tahoe (California) and Asiago (Alps). While texture was useful to improve the model performance, the best model was obtained using joined SAR and NDVI (R2 equal to 0.66). In this model, only a slight saturation was observed, at higher levels than what usually reported in literature for SAR; the trend requires further investigation but the model confirmed the complementarity of optical and SAR datatypes. For comparison purposes, we also generated a biomass map for Asiago using lidar data, and considered a previous lidar-based study for Tahoe; in these areas, the observed R2 were 0.92 for Tahoe and 0.75 for Asiago, respectively. The quantitative comparison of the carbon stocks obtained with the two methods allows discussion of sensor suitability. The range of local variation captured by lidar is higher than those by SAR and NDVI, with the latter showing overestimation. However, this overestimation is very limited for one of the study areas, suggesting that when the purpose is the overall quantification of the stored carbon, especially in areas with high carbon density, satellite data with lower cost and broad coverage can be as effective as lidar

Signals from the Government: Policy Uncertainty and the Transmission of Fiscal Shocks

In this paper, we investigate the influence of fiscal policy uncertainty in the propagation of government spending shocks in the US economy. We propose a new index to measure fiscal policy uncertainty which relies on the dispersion of government spending forecasts as presented in the Survey of Professional Forecasters (SPF). This new index is solely focused on the uncertainty surrounding federal spending and is immune from the influence of general macroeconomic uncertainty by as much as is possible. Our results indicate that, in times of elevated fiscal policy uncertainty, the output response to policy announcements about future government spending growth is muted. Instead, periods of low policy uncertainty are characterised by a positive and persistent output response to fiscal announcements. Our analysis also shows that the stronger effects of fiscal policy in less uncertain times is mainly the result of agents’ tendency to increase investment decisions in these periods, in line with the prediction of the option value theory in Bernanke (1983)

Signals from the Government: Policy Uncertainty and the Transmission of Fiscal Shocks

In this paper, we investigate the influence of fiscal policy uncertainty in the propagation of government spending shocks in the US economy. We propose a new index to measure fiscal policy uncertainty which relies on the dispersion of government spending forecasts as presented in the Survey of Professional Forecasters (SPF). This new index is solely focused on the uncertainty surrounding federal spending and is immune from the influence of general macroeconomic uncertainty by as much as is possible. Our results indicate that, in times of elevated fiscal policy uncertainty, the output response to policy announcements about future government spending growth is muted. Instead, periods of low policy uncertainty are characterised by a positive and persistent output response to fiscal announcements. Our analysis also shows that the stronger effects of fiscal policy in less uncertain times is mainly the result of agents’ tendency to increase investment decisions in these periods, in line with the prediction of the option value theory in Bernanke (1983)

Una applicazione dell’Indice di Funzionalità Fluviale in Calabria. Il caso studio del torrente Verri

Questo studio si propone di valutare lo stato di salute ecologica e la funzionalità ecosistemica del bacino idrografico del torrente Verri attraverso l’applicazione della nuova versione dell’Indice di Funzionalità Fluviale (IFF 2007). I risultati evidenziano il buon grado di funzionalità fluviale del bacino idrografico in esame sebbene alcuni tratti nella zona di deposito siano compromessi nelle loro componenti biotiche ed abiotiche a causa della presenza di numerose captazioni e derivazioni idriche utilizzate a scopo irriguo ed agricolo

Geochemical Characterization of Spring Waters in the Crati River Basin, Calabria (Southern Italy)

The characterization of the spatial variation of geochemical parameters in spring waters, especially the ones used for drinking purpose, is essential to identify potential risks to humans. In this work, results of a qualitative analysis on 190 samples of spring waters collected in the largest catchment of the Calabria region (southern Italy) are shown. Several physical and chemical parameters were analysed and the Langelier-Ludwig diagram was built to evaluate the hydrochemical facies of the sampled waters. Additionally, the relationships between water temperature and altitude and electric conductivity (EC) and altitude were assessed. Geostatistical methods were used to map the physical and chemical parameters. Results showed a good quality status of the spring waters in the Crati basin, with a predominant Ca-Mg-type hydrochemical facies. Then, a connection between EC and temperature with elevation has been detected in some area of the basin. Finally, the spatial analysis allowed identifying the distribution of the concentration of the several parameters