Employment, Hours per Worker and the Business Cycle.

We examine the impact that technology shocks have in a trivariate VAR that includes productivity, hours worked per person and the employment ratio. These last two variables have trends that make them non-stationary. There are three results of interest. First, a technology shock reduces both hours and employment if those two variables are specified in first differences, with the response of employment being stronger than the response of hours. Second, a technology shock increases both hours and employment, when those two variables are specified in levels, although in this case the response of hours worked per person is stronger. Third, considering the possibility of changes in the trend growth rate of productivity reverses the results for the VARs with data in levels only. We also present a real business cycle model capable of replicating some of the results for hours and employment.Business cycles, Employment, Hours worked, Technology shocks

Consumption Theory

There is no doubt that aggregate consumption is a key variable for policy makers. The aim of this handbook is to familiarise the reader with the key theories that have been used to model and forecast consumption and draw out their implications for policy analysis. This handbook is intended to be accessible to those working in policy-related departments without losing economic rigour. Important concepts are highlighted in a series of four boxes and technical details in four appendices. The handbook pays particular attention to the role of forward-looking agents and their reaction to policy announcements; the role of interest rates in consumption and the role of other variables thought to affect consumption behaviour such as taxes, the structure of both the banking system and the stock market, age and wealth distributions and the volatility of economic variables. Unfortunately, different consumption theories can lead to different policy prescriptions and as such a clear message arises from this handbook: there is no single consumption theory that can explain consumption behaviour in all economies; economists must therefore investigate what they think explains consumption in their country.Consumption Theory

The Impact of Trend Inflation in an Open Economy Model

Most New Keynesian models are derived under the assumption that inflation is equal to zero in the steady-state and yet most central banks around the world have inflation targets that are greater than such a number. In this paper we consider the open economy (welfare) implications of non-zero steady-state inflation rates both in the domestic and foreign economies. We show that higher inflation rates in the steady-state, both in the domestic and foreign economies, reduce welfare in the domestic economy. We also show that high domestic inflation rates in the steady-state have a more adverse effect on domestic welfare than high foreign inflation rates.Optimal Monetary Policy, Trend Inflation, Open Economy Macroeconomics

Two exchange-correlation functionals compared for first-principles liquid water

The first-principles description of liquid water using ab initio molecular dynamics (AIMD) based on Density Functional theory (DFT) has recently been found to require long equilibration times, giving too low diffusivities and a clear over-structuring of the liquid. In the light of these findings we compare here the room-temperature description offered by two different exchange correlation functionals: BLYP, the most popular for liquid water so far, and RPBE, a revision of the widely used PBE. We find for RPBE a less structured liquid with radial distribution functions closer to the experimental ones than the ones of BLYP. The diffusivity obtained with RPBE for heavy water is still 20% lower than the corresponding experimental value, but it represents a substantial improvement on the BLYP value, one order of magnitude lower than experiment. These characteristics and the hydrogen-bond (HB) network imperfection point to an effective temperature ~3% lower than the actual simulation temperature for the RPBE liquid, as compared with BLYP's ~17% deviation. The too long O--O average nearest-neighbor distance observed points to an excessively weak HB, possibly compensating more fundamental errors in the DFT description.Comment: Jorunal reference adde

Understanding the macroeconomic effects of working capital in the United Kingdom

In this paper we first document the behaviour of working capital over the business cycle stressing the large negative effect of the recent credit contraction on UK firms working capital positions. In order to understand the effects of working capital on macroeconomic variables, we solve and calibrate an otherwise standard flexibleprice DSGE model that introduces an explicit role for the components of working capital as well as a banking sector which intermediates credit. We find that financial intermediation shocks, similar to those experienced post-2007, have persistent negative effects on economic activity ; these effects are reinforced by reductions in trade credit. Our model admits a crucial role for monetary policy to offset such shocks. Key words: Working capital ; business cycle model ; spreads ; financial crisis. JEL classification: E20 ; E51 ; E52

NO3- selective mini-electrodes as a tool to investigate the NO3- traffic in Chlamydomonas reinhardtii D.

Ion selective NO3- mini-electrodes were used to measure the external NO3- concentration in C. reinhardtii liquid cultures. Electrodes were prepared using glass capillaries (1.5 mm external diameter). Capillaries were cut in 10 cm long pieces, dehydrated for 45 minutes in an oven and silanized by addition of dimethyldichlorosilane in bencene 0.1% (V/V). Once silanized, the capillaries were baked again for 30 minutes. Once cold the capillaries were backfilled with the NO3- ionophore (Fluka: 72549), which contains PVC (5.75% w/w) dissolved in tetrahydrofurane. Then, the NO3- mini-electrodes were stored in dark in a desiccator until tetrahydrofurane gets evaporated. Before use, NO3- selective mini-electrodes were backfilled with 0.1 M NaNO3 and 0.1 M KCl and connected to a high-impedance differential amplifier (WPI FD223). Mini-electrodes were calibrated in N-free Beijerinck medium, which contains 0.1 mM Cl-. In those conditions, electrodes calibration slope was 54 mV/p NO3- in the range 1 - 1000 µM NO3-. The mini-electrodes were used to continuous monitoring of the external NO3- concentration in liquid culture of different C. reinhardtii strains, incubated in N-free Beijerinck medium supplemented with 100 µM NO3Na. Previous to the assays, strains were N starved for 6 days. In the light, wild type strain uptakes NO3- at a rate of 15 nmol NO3-·106 cells-1·h-1, in the dark this rate was one third of this figure. After 5 h, the external NO3- levelled off at 10 µM in the light and around 30 µM in the dark. C. reinhardtii cells cultured in the presence of 2 mM NO3NH4 do not show significant NO3- uptake nor a mutant strain, defective in nitrate transport and having an active nitrate reductase. However, a mutant strain lacking the nitrate reductase shows an enhanced NO3- uptake rate, compared with the value obtained for the wild type in the light.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Alternative method for the metrological characterization of spur gears in the sub-millimeter range using optical equipment

The aim of this work is to develop a software that allows the inspection of spur gear manufactured in the sub-millimeter range. The measurements are made using a digital optical machine and using an analysis proprietary software implemented in Matlab®, which is able to handle images, captured using the digital optical machine. The software allows to evaluate the profile and pitch deviations as establish in the ISO/TR 10064-1:1992 standar

Microalgae: The Basis of Mankind Sustainability

Microalgae were the basis of life into the planet, but only recently these microorganisms are exploited at a commercial scale. Thus, the production of pharmaceuticals, cosmetics, feed, and foods from microalgae is today a commercial reality increasing year by year. Additionally, microalgae have been proposed to be used to enhance the sustainability of existing industrial activities, as wastewater treatment and biofuel production. In this way, the utilization of microalgae at a large scale is considered a green revolution in the sustainability of mankind. This chapter is focused on reviewing the real contribution of microalgae to human activities. The last improvements of technologies and its uses, in addition to still existing bottlenecks for the massive exploitation of these microorganisms, are reviewed

Analisis de la oferta de las universidades gallegas

Este trabajo tiene como objetivo analizar, por un lado, la evolución de la oferta universitaria gallega, y por otro, en qué posición queda cada universidad para afrontar los próximos años en los que se producirá una drástica reducción en el número de alumnos. Para ello, aplicamos un análisis cluster mediante el cual se agrupan las titulaciones del sistema universitario gallego en función de una serie de variables representativas, tanto de la oferta como de la demanda.