Import Price-Elastcities: Reconsidering the Evidence

Recent geography and trade empirical studies based on monopolistic competition [Hummels, 1998; Hanson, 1999; Head and Ries, 1999] suggest high levels of trade price-elasticities (between 3 and 11). However, direct estimations of price-elasticities in trade equations, using price indexes at the aggregate or industry levels, lead to much lower values than those predicted by the prior studies and the theory (usually around unity). In this article, we show that these inconclusive results may be due to an econometric misspecification of the trade equations, to measurement errors in import price indexes as well as endogeneity problems. We re-estimate import price-elasticities from gravity-like equations using methods of transformed least squares and instrumental variables. Our study is based on compatible bilateral trade and activity data from the OECD and INSEE1 for 14 import countries, 16 trading partners, 27 industries and 23 years. When suitable instrumental variables are used, we find relatively high price-elasticities, usually ranging from 1 to 7, the highest estimates corresponding to industries producing homogeneous goods. Our results constitute a first step towards a reconciliation of the theory and the evidence.

Two cheers for the Monetary Control Act

This article explains how the Monetary Control Act (MCA) of 1980 paved the way for the transition away from paper to electronic check clearing and processing, ultimately leading to the successful implementation of the Check Clearing for the 21st Century Act (Check 21) in 2003.Monetary policy ; Monetary policy - United States

Unsteady Radiative Transfer in Participating Media: a Frequency-Based Numerical Approach

Abstract The one-dimensional transient radiative transfer problem in the Cartesian coordinate system -an absorbing and scattering medium illuminated by a short laser pulse -is solved by the use of a Discrete Ordinates -Finite Volume method. Previous works have shown that the original numerical approach, based in the space-time domain, induces transmitted flux emerging earlier than the minimal time required by the radiation to leave the medium. Therefore, a frequency-based numerical method is formulated implemented, and validated in this paper. Results for transmittances are accurate, without physically unrealistic behaviors at early time periods. However, the frequency-dependent approach is computationally expensive; it requires approximately five times more computational time than its temporal counterpart. The next step will be devoted to the optimization of these CPU requirements

Analyse des systèmes de génération d’électricité pour les sites isolés basés sur l’utilisation du stockage d’air comprimé en hybridation avec un jumelage éolien-diesel

Dans les sites isolés (grand nord du Canada, Mines, îles, Mines, bases scientifiques et militaires, stations de télécommunications, etc.), des génératrices diesel sont utilisées pour produire de l’électricité. Cette méthode est relativement inefficace, très onéreuse et responsable de l’émission de grandes quantités de gaz à effet de serre. Hydro-Québec estime à environ 133M$ les pertes annuelles subies pour électrifier des sites non reliés à son réseau principal. L’utilisation d’un système hybride éolien-diesel à haute pénétration associé à un dispositif de stockage sous forme d’air comprimé pourrait donc réduire les déficits d’exploitation dans ces réseaux autonomes. Dans cet article les problématiques de l’électrification des sites isolés et le principe de fonctionnement de la solution proposée (système hybride éolien-diesel air comprimé : SHEDAC) seront présentés d’une manière sommaire. Ensuite, deux études de cas seront traitées et analysées et ceci pour deux types d’application : station de télécommunication (à petite échelle) et village nordique (à moyenne échelle) dans l’objectif de dégager le potentiel de ces solutions pour l’électrification des régions éloignées du réseau centrale de transport et distribution de l’électricité

Demythologizing the Third Realm: Frege on Grasping Thoughts

In this paper, I address some puzzles about Frege’s conception of how we “grasp ” thoughts. I focus on an enigmatic passage that appears near the end of Frege’s great essay “The Thought. ” In this passage Frege refers to a “non-sensible something ” without which “everyone would remain shut up in his inner world. ” I consider and criticize Wolfgang Malzkorn’s interpretation of the passage. According to Malzkorn, Frege’s view is that ideas [Vorstellungen] are the means by which we grasp thoughts. My counter-proposal is that language enables us to grasp thoughts (ideas are merely their baggage or “trappings, ” as Frege puts it). One significant consequence of my interpretation is that it helps challenge the standard reading of Frege according to which he is a metaphysical platonist about thoughts. My interpretation thus provides support for the deflationary, anti-ontological reading spelled out by read-ers like Thomas Ricketts and Wolfgang Carl. As Ricketts puts it, Frege’s distinction between the objective and the subjective, rather than being an ontological doctrine, “lodges in the contrast be-tween asserting something and giving vent to a feeling.

Anaerobic digestion and gasification coupling for wastewater sludge treatment and recovery

ABSTRACT Sewage sludge management is an energy intensive process. Anaerobic digestion contributes to energy efficiency improvement but is limited by the biological process. A review has been conducted in order to evaluate the mass and energy balances on anaerobic digestion followed by gasification of digested sludge in order to improve energy recovery. Calculations are based on design parameters and tests that are conducted with the anaerobic digester of a local wastewater treatment plant and a small commercial gasification system. Results show a very important potential of energy recovery. More than 95% of the energy content from sludge was extracted. This extraction resulted in a 5% reduction of biogas but final product was a totally dry biochar. Final product was then a fraction of the initial mass. This analysis suggests that anaerobic digestion followed by dewatering, drying and gasification could be a promising and viable option for energy and nutrient recovery from municipal sludge in replacement of conventional paths

Anaerobic digestion and gasification coupling for wastewater sludge treatment and recovery

ABSTRACT Sewage sludge management is an energy intensive process. Anaerobic digestion contributes to energy efficiency improvement but is limited by the biological process. A review has been conducted prior to experimentation in order to evaluate the mass and energy balances on anaerobic digestion followed by gasification of digested sludge. The purpose was to improve energy recovery and reuse. Calculations were based on design parameters and tests that are conducted with the anaerobic digester of a local wastewater treatment plant and a small commercial gasification system. Results showed a very significant potential of energy recovery. More than 90% of the energy content from sludge was extracted. Also, about the same amount of energy would be transferred to the gasifier (biogas) as thermal energy to the digester. This extraction resulted in the same use of biogas as the reference scenario but final product was a totally dry biochar which represented a fraction of the initial mass. Phosphorus was concentrated and significantly preserved. This analysis suggests that anaerobic digestion followed by dehydration, drying and gasification could be a promising and viable option for energy and nutrient recovery from municipal sludge in replacement of conventional paths

Paleomagnetic evidence for rapid vertical-axis rotation in the Peruvian Cordillera ca. 8 Ma

Paleomagnetic results from 31 Neogene sites in the Peruvian Andes yield primary magnetizations, as demonstrated by positive fold and reversal tests. Strata dated as 18–9 Ma record a significant counterclockwise rotation (−11° ± 5°), whereas unconformably overlying younger strata (7–6 Ma) are not rotated. The age of rotation thus is between 9 and 7 Ma, a period that coincides with the widespread Quechua 2 deformation phase. Moreover, eight independent studies on 107–9 Ma rocks from Peru between 9°S and 15°S reveal similar and significant rotations (−15° ± 6°). This suggests that the region rotated during a 2 m.y. period of deformation ca. 8 Ma, when the Andes underwent rapid uplift and important deformation commenced in the Subandean zone

Improving ionic conductivity by Mg-doping of A2SnO3 (A=Li+, Na+)

The search for Li ions conducting ceramics is burgeoning, owing to the regain interest for solid state batteries. Here we investigate the effect of Mg substitutions on the ionic conductivity of the A2SnO3 (A=Li, Na) phases. Pure A1.8Mg0.1SnO3 and A2.2Mg0.1Sn0.9O3 were structurally characterized and their ionic conductivity was measured by AC impedance spectroscopy. We show a decrease of the activation energy with increasing the Mg substitution and found ionic conductivities three and two orders of magnitude higher for Li2.2Mg0.1Sn0.9O3 and Na1.8Mg0.1SnO3 as compared to pristine Li2SnO3 and Na2SnO3, respectively. Neutron diffraction was used to determine the Mg localization in the crystal structure and to provide a rationale for the ionic conductivity changes. Our results confirm the high sensitivity of the ionic conductivity on chemical substitutions, even limited ones