Updated constraints on spatial variations of the fine-structure constant

Recent work by Webb {\it et al.} has provided indications of spatial variations of the fine-structure constant, $\alpha$, at a level of a few parts per million. Using a dataset of 293 archival measurements, they further show that a dipole provides a statistically good fit to the data, a result subsequently confirmed by other authors. Here we show that a more recent dataset of dedicated measurements further constrains these variations: although there are only 10 such measurements, their uncertainties are considerably smaller. We find that a dipolar variation is still a good fit to the combined dataset, but the amplitude of such a dipole must be somewhat smaller: $8.1\pm1.7$ ppm for the full dataset, versus $9.4\pm2.2$ ppm for the Webb {\it et al.} data alone, both at the $68.3\%$ confidence level. Constraints on the direction on the sky of such a dipole are also significantly improved. On the other hand the data can't yet discriminate between a pure spatial dipole and one with an additional redshift dependence.Comment: 10 pages, 4 figure

Searching for sectoral patterns of innovation in european manufacturing industry

The present paper is conducted under the research project “Enterprise of the Future: Trends and Scenarios towards Competitiveness” which attempts to disclosure determinants of future enterprise competitiveness. Innovation is not only a must today but also an imperative in future competitiveness scenarios. In modern evolutionary economics it is argued that sector-specific factors are one of the key factors explaining innovative behaviour and performance of firms. Several contributions have pointed that industries largely differ in terms of knowledge base and technological sources, opportunities and appropriation of innovative activities, technological trajectories and firms’ strategies. Using as background Pavitt’s taxonomy, this paper explores the nature, extent and sources of variety of innovation in the manufacturing industry, aiming at identifying common patterns across industries, and sectoral patterns across countries. This paper presents evidence based on the aggregated results of the last IV Community Innovation Survey released by EUROSTAT (CIS4), for which data is available for a number of industries and countries

Constraining spatial variations of the fine-structure constant in symmetron models

We introduce a methodology to test models with spatial variations of the fine-structure constant $\alpha$, based on the calculation of the angular power spectrum of these measurements. This methodology enables comparisons of observations and theoretical models through their predictions on the statistics of the $\alpha$ variation. Here we apply it to the case of symmetron models. We find no indications of deviations from the standard behavior, with current data providing an upper limit to the strength of the symmetron coupling to gravity ($\log{\beta^2}<-0.9$) when this is the only free parameter, and not able to constrain the model when also the symmetry breaking scale factor $a_{SSB}$ is free to vary.Comment: Phys. Lett. B (in press

Exploring economic and policy determinants of FDI. A panel data analysis

During the past decades, the world economy has witnessed a dramatic surge in foreign direct investment. There is increasing competition among economies in attracting inflows of FDI. There has been renewed research interest in trying to detect what are the economic and political conditions that make a local economy an attractive destination for FDI inflows. Hence, in this paper we investigate macroeconomic and locational variables that may influence the level of FDI in a group of countries as a whole. In this paper we explore not only economic but also policy variables in terms of trade policy and regulation, and their effects on foreign direct investment. The evidence is captured by panel data analysis, which pools together 29 countries over the period 1990-2005. Overall our research shows that the distribution of FDI across countries is strongly determined by economic fundamentals and broad policies affecting foreign owned and domestic firms alike. Strategic and endurable horizontal policies, education and training in particular, can do much for the latter. There is scope for policies that are costless in the sense of having no immediate budgetary implications, namely the reduction of remaining impediments to trade

Qualidade de milho verde cultivado em sistemas de produção orgânico e convencional.

Avaliaram-se as características agronômicas e físico-químicas de milho verde cultivado em sistemas de produção orgânico e convencional. Utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 4 x 2, sendo quatro cultivares (AG 1051, BR 106, SWB 551 e VIVI), nos sistemas orgânico e convencional, com três repetições. As características agronômicas analisadas foram peso das espigas com palhas (PP) e despalhadas (PD), peso dos grãos (PG), peso do sabugo (PS), peso da palha (P), comprimento da espiga com palha (CE), percentual relativo de grãos (PRG), percentual relativo de palha (PRP) e percentual relativo de sabugo (PRS). Foram, ainda, analisados o teor de umidade e as características físico-químicas (pH, acidez titulável e sólidos solúveis totais) dos grãos verdes. As espigas produzidas no sistema convencional apresentaram PP, PD e PG superiores aos das espigas produzidas em sistema orgânico, para a cultivar AG 1051. O mesmo comportamento foi observado para o CE da cultivar SWB 551 e o PG da cultivar BR 106. No sistema convencional, a cultivar AG 1051 destacou-se nas características agronômicas avaliadas. Os valores médios de pH, diferentemente da acidez, foram superiores no cultivo orgânico. A cultivar SWB 551 apresentou maior percentual de sólidos solúveis entre as cultivares. Portanto, o sistema de produção influencia as principais características de qualidade do milho verde