Luis Lopes

Are small firms more dependent on the local environment than larger firms? Evidence from Portuguese manufacturing firms

This paper analyses the impact on firm-level total factor productivity of both agglomeration economies and regional knowledge, using an unbalanced panel of Portuguese manufacturing firms covering the period 1996–2004. Controlling for the endogeneity problem using the Arellano and Bond (1991) difference GMM estimator, we found that both localization and urbanization economies have a significant and positive effect on firms’ TFP, with the latter playing the most important role. Sectoral specialization economies are important for small and medium firms, but not for large firms. However, larger firms profit more from regional knowledge than smaller ones.

Performance of the HADES-TOF RPC wall in a Au-Au beam

In this work we present results concerning in beam operation of the new Resistive Plate Chamber (RPC) Time of Flight (TOF) wall for the High-Acceptance DiEl ectron Spectrometer (HADES) spectrometer at GSI. The new RPC-TOF wall, fully integrated in the spectrometer, has been successfully operated under final conditions corresponding to collision of Au + AU @ 1.25 GeV. Results confirm an uniform average time response below 80 ps σ along with an average longitudinal position resolution better than 12 mm σ . The multihit capability of the system has also been investigated showing a slight degradation of time reso lution when particles hit the detector at neighbouring cells, which demonstrates the multihit capability of the concept (individually electrically shielded RPCs).

Design and expected performance of a novel hybrid detector for very-high-energy gamma-ray astrophysics

Abstract Current detectors for Very-High-Energy γ-ray astrophysics are either pointing instruments with a small field of view (Cherenkov telescopes), or large field-of-view instruments with relatively large energy thresholds (extensive air shower detectors). In this article, we propose a new hybrid extensive air shower detector sensitive in an energy region starting from about 100u202fGeV. The detector combines a small water-Cherenkov detector, able to provide a calorimetric measurement of shower particles at ground, with resistive plate chambers which contribute significantly to the accurate shower geometry reconstruction. A full simulation of this detector concept shows that it is able to reach better sensitivity than any previous gamma-ray wide field-of-view experiment in the sub-TeV energy region. It is expected to detect with a 5σ significance a source fainter than the Crab Nebula in one year at 100xa0GeV and, above 1u2009TeV a source as faint as 10% of it. As such, this instrument is suited to detect transient phenomena making it a very powerful tool to trigger observations of variable sources and to detect transients coupled to gravitational waves and gamma-ray bursts.

Autonomous RPCs for a Cosmic Ray ground array

We report on the behaviour of Resistive Plate Chambers (RPC) developed for muon detection in ultra-high energy cosmic ray (UHECR) experiments. The RPCs were developed for the MARTA project and were tested on field conditions. These RPCs cover an area of

LATTES: a new gamma-ray detector concept for South America

1.5 times 1.2,{m^2}

Experimental sub-millimeter resolution with a small-animal RPC-PET prototype

and are instrumented with 64 pickup electrodes providing a segmentation better than

Regional knowledge spillovers: a firm-based analysis of non-linear effects

20,

LATTES: a novel detector concept for a gamma-ray experiment in the Southern hemisphere

cm. By shielding the detector units with enough slant mass to absorb the electromagnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme environmental conditions, with limited budgets for power and minimal maintenance. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminium-sealed case, providing a compact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using a very low gas flux, which allows running them for few years with a small gas reservoir. Several prototypes have already been built and tested both in the laboratory and outdoors. We report on the most recent tests done in the field that show that the developed RPCs have operated in a stable way for more than 2 years in field conditions.

Achieving 0.4-mm FWHM spatial resolution with an RPC-based small-animal PET prototype

Currently the detection of Very High Energy gamma-rays for astrophysics rely on the measurement of the Extensive Air Showers (EAS) either using Cherenkov detectors or EAS arrays with larger field of views but also larger energy thresholds. In this talk we present a novel hybrid detector concept for a EAS array with an improved sensitivity in the lower energies (

Analysis of the front structure of EAS with the HADES tRPC wall

sim 100,