(Fractional) Beta Convergence

Unit roots in output, an exponential 2 per cent rate of convergence and no change in the underlying dynamics of output seem to be three stylized facts that cannot go together. This paper extends the Solow-Swan growth model allowing for cross-sectional heterogeneity. In this framework, aggregate shocks might vanish at a hyperbolic rather than at an exponential rate. This implies that the level of output can exhibit long memory and that standard tests fail to reject the null of a unit root despite mean reversion. Exploiting secular time series properties GDP, we conclude that traditional approaches to test for uniform (conditional and unconditional) convergence suit first step approximation. We show both theoretically and empirically how the uniform 2 per cent rate of convergence repeatedly found in the empirical literature is the outcome of an underlying parameter of fractional integration strictly between 1/2 and 1. This is consistent with both time series and cross-sectional evidence recently produced.growth model, convergence, long memory, aggregation

The Effects of Labor Market Conditions on Working Time: the US-EU Experience

We consider a labor market search model where, by working longer hours, individuals acquire greater skills and thereby obtain better jobs. We show that job inequality, which leads to within-skill wage differences, gives incentives to work longer hours. By contrast, a higher probability of losing jobs, a longer duration of unemployment, and in general a less tight labor market discourage working time. We show that the different evolution of labor market conditions in the US and in Continental Europe over the last three decades can quantitatively explain the diverging evolution of the number of hours worked per employee across the two sides of the Atlantic. It can also explain why the fraction of prime age male workers working very long hours has increased substantially in the US, after reverting a trend of secular decline.working hours, wage inequality, unemployment, search, human capital filtering

The ins and outs of unemployment: An analysis conditional on technology shocks

We analyze how unemployment, job finding and job separation rates react to neutral and investment-specific technology shocks. Neutral shocks increase unemployment and explain a substantial portion of it volatility; investment-specific shocks expand employment and hours worked and contribute to hours worked volatility. Movements in the job separation rates are responsible for the impact response of unemployment while job finding rates for movements along its adjustment path. The evidence warns against using models with exogenous separation rates and challenges the conventional way of modelling technology shocks in search and sticky price models.Unemployment, technological progress, labor market flows, business cycle models.

On the robust effects of technology shocks on hours worked and output

We analyze the effects of neutral and investment-specific technology shocks on hours and output. Long cycles in hours are captured in a variety of ways. Hours robustly fall in response to neutral shocks and robustly increase in response to investment specific shocks. The percentage of the variance of hours (output) explained by neutral shocks is small (large); the opposite is true for investment specific shocks. ‘News shocks’ are uncorrelated with the estimated technology shocks.Technology disturbances, structural VARs, low frequency movements, news shocks

Schumpeterian technology shocks

We analyze the labor market effects of neutral and investment-specific technology shocks along the intensive margin (hours worked) and the extensive margin (unemployment). We characterize the dynamic response of unemployment in terms of the job separation and the job finding rate. Labor market adjustments occur along the extensive margin in response to neutral shocks, along the intensive margin in response to investment specific shocks. The job separation rate accounts for a major portion of the impact response of unemployment. Neutral shocks prompt a contemporaneous increase in unemployment because of a sharp rise in the separation rate. This is prolonged by a persistent fall in the job finding rate. Investment specific shocks rise employment and hours worked. Neutral shocks explain a substantial portion of the volatility of unemployment and output; investment specific shocks mainly explain hours worked volatility. This suggests that neutral progress is consistent with Schumpeterian creative destruction, while investment-specific progress operates as in a neoclassical growth model.Search frictions, technological progress, creative destruction

Preparation and purification of Flavobacterium heparinum chondroitinases AC and B by hydrophobic interaction chromatography

Flavobacterium heparinum is a soil bacterium that produces several mucopolysaccharidases such as heparinase, heparitinases I and II, and chondroitinases AC, B, C and ABC. The purpose of the present study was to optimize the preparation of F. heparinum chondroitinases, which are very useful tools for the identification and structural characterization of chondroitin and dermatan sulfates. We observed that during the routine procedure for cell disruption (ultrasound, 100 kHz, 5 min) some of the chondroitinase B activity was lost. Using milder conditions (2 min), most of the chondroitinase B and AC protein was solubilized and the enzyme activities were preserved. Tryptic soy broth without glucose was the best culture medium both for bacterial growth and enzyme induction. Chondroitinases AC and B were separated from each other and also from glucuronidases and sulfatases by hydrophobic interaction chromatography on HP Phenyl-Sepharose. A rapid method for screening of the column fractions was also developed based on the metachromatic shift of the color of dimethylmethylene blue.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

Spillovers of Equal Treatment in Wage Offers

We analyse a labour matching model with wage posting, where re flecting institutional constraints firms cannot differentiate their wage offers within certain subsets of workers. Inter alia, we find that the presence of impersonal wage offers leads to wage compression, which propagates to the wages for high productivity workers who receive personalised offers

Business Creation and the Stock Market

We claim that the stock market encourages business creation, innovation, and growth by allowing the recycling of ``informed'' capital. Due to incentive problems, financing new innovative businesses requires entrepreneurs either to sustain a tight relationship with monitors (banks, venture capitalists) whose ``informed'' capital is in limited supply or to undertake an irreversible reorganization that makes the firm transparent enough to access the stock market. We characterize the financial life cycle of firms, showing why they choose to be initially financed through informed capital, reconsidering whether to go public once some uncertainty is resolved. We examine the efficiency properties of the competitive equilibrium and identify the factors that lead to the emergence of a stock market for young fast growing firms, facilitate the recycling of informed capital, and encourage business creation. We also show how the rate of technological progress affects and is affected by stock market development.

Characterization of an emergent clone of enteroinvasive Escherichia coli circulating in Europe

Enteroinvasive Escherichia coli (EIEC) cause intestinal illness indistinguishable from that caused by Shigella, mainly in developing countries. Recently an upsurge of cases of EIEC infections has been observed in Europe, with two large outbreaks occurring in Italy and in the United Kingdom. We have characterized phenotypically and genotypically the strains responsible for these epidemics together with an additional isolate from a sporadic case isolated in Spain. The three isolates belonged to the same rare serotype O96:H19 and were of sequence type ST-99, never reported before in EIEC or Shigella. The EIEC strains investigated possessed all the virulence genes harboured on the large plasmid conferring the invasive phenotype to EIEC and Shigella while showing only some of the known chromosomal virulence genes and none of the described pathoadaptative mutations. At the same time, they displayed motility abilities and biochemical requirements resembling more closely those of the non-pathogenic E. coli rather than the EIEC and Shigella strains used as reference. Our observations suggested that the O96:H19 strains belong to an emerging EIEC clone, which could be the result of a recent event of acquisition of the invasion plasmid by commensal E. coli

Investigating the Efficiency of ITS Cooperative Systems for a Better Use of Urban Transport Infrastructures: The iTETRIS Simulation Platform

The use of cooperative ITS communication systems, supporting driving through the dynamic exchange of Vehicle-to- Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) messages, is a potential candidate to improve the economical and societal welfare. The application of such systems for novel cooperative traffic management strategies can introduce a lot of beneficial effects not only for road safety, but also for the economy related to transportation systems and the environmental impact. Despite this apparent set of promising features, City Road Authorities, which hold a key-role in determining the final adoption of such systems, still look at cooperative systems without sharing a clear opinion. This is mainly due to the current lack of definitive and solid evidences of the effectiveness of such systems when applied in the real world. In order to fill this gap and let Road Authorities estimate the usefulness of such technologies in achieving the objectives dictated by cities’ traffic management policies, the EU consortium iTETRIS is developing a simulation platform for large scale testing of traffic management solutions making use of cooperative ITS systems. Thanks to its own distinguishing features, iTETRIS aims at becoming a good supporting tool for Road Authorities to implement preliminary tests on the effectiveness of ITS solutions prior to investing money for the physical deployment of the communication infrastructures allowing their functioning