Duality in two capacitively coupled layered arrays of ultrasmall Josephson junctions

We consider the problem of two capacitively coupled Josephson junction arrays made of ultrasmall junctions. Each one of the arrays can be in the semiclassical or quantum regimes, depending on their physical parameter values. The former case is dominated by a Cooper-pair superfluid while the quantum one is dominated by dynamic vortices leading to an insulating behavior. We first consider the limit when both arrays are in the semiclassical limit, and next the case when one array is quantum and the other semiclassical. We present WKB and Mean Field theory results for the critical temperature of each array when both are in the semiclassical limit. When one array is in the semiclassical regime and the other one in the quantum fluctuations dominated regimes, we derive a duality transformation between the charged and vortex dominated arrays that involve a gauge vector field, which is proportional to the site coupling capacitance between the arrays. The system considered here has been fabricated and we make some predictions as to possible experimentally measurable quantities that could be compared with theory.Comment: 25 pages in Revtex, To appear in J. Stat. Physics In the November 1998 issu

Immigrant’s Characteristics and their different effects on bilateral trade. Evidence from Spain.

This paper tests for the impact of immigration on bilateral trade using Spanish data from 1995 to 2003. It also explores some possible mechanisms behind this link. It uses a gravity equation for trade augmented with an immigrants stock variable and a set of control variables. The immigrants variable enters the estimated equation in different ways depending on immigrant relevant characteristics both individual and non individual-specific. Results show that there is a positive link between immigration and both exports and imports. We find evidence for the trade transaction cost channel but not for the preference one. The mechanisms behind this link are the information effect – immigrant’s additional information about product and about social and political institutions - and the social o ethnic network effect - immigrants with a medium level of education and those related to business activities are the one who have a positive effect on bilateral trade.International Trade, Migration.

Comparative study of Sustainability Metrics for Face Milling AISI 1045 in different Machining Centers

Comunicación presentada a MESIC 2019 8th Manufacturing Engineering Society International Conference (Madrid, 19-21 de Junio de 2019)The objective of this study is to compare a set of sustainability metrics between different manufacturing resources applied to high performances machining centers. The research compares distributed scenarios in order to find the optimal conditions that allow the minimum consumed power and the minimum roughness when performing face milling operations of AISI 1045 steel. The set of experiments for the surface machining was carried out considering different path strategies in three main directions for two dimensional movements of the tool. The selected experiments considered the main axis movement, the perpendicular axis movement and a 45 degrees movement. Besides, it was considered the feed rate speed and the cutting depth. The design of experiments was developed with the Taguchi method considering an orthogonal matrix of L27 design type, and three levels of experimental design, and the analysis of variance and noise signal were performed. The methodology to determine the lowest power consumed and the best surface quality allowed to establish the working condition in the most sustainable machining. The results show how the cutting parameters influence in each manufacturing resource

ASSESSING THE "ENGINES OF LIBERATION": HOME APPLIANCES AND FEMALE LABOR FORCE PARTICIPATION

The secular rise in female labor force participation, highlighted in the recent macroeconomics literature on growth and structural change, has been associated with the declining price and wider availability of home appliances. This paper uses a new and unique country dataset on the price of home appliances to test its impact on female labor supply. We assess the role of the price of appliances in raising participation by comparing it to the impact of fertility and other macroeconomic factors. A decrease in the relative price of appliances - the ratio of the price of appliances to the consumer price index - leads to a substantial and statistically significant increase in female labor force participation. The impact of the price of appliances is quantitatively of the same order of magnitude as that of fertility. This result is robust to the inclusion of additional controls, such as income per capita, government spending, and male and female unemployment rates. To assess causality, we test for exogeneity and use the lagged relative price of appliances and the food price index as instrumental variables, confirming that lower appliance prices lead to increased female participation.