Positioning systems in Minkowski space-time: Bifurcation problem and observational data

In the framework of relativistic positioning systems in Minkowski space-time, the determination of the inertial coordinates of a user involves the {\em bifurcation problem} (which is the indeterminate location of a pair of different events receiving the same emission coordinates). To solve it, in addition to the user emission coordinates and the emitter positions in inertial coordinates, it may happen that the user needs to know {\em independently} the orientation of its emission coordinates. Assuming that the user may observe the relative positions of the four emitters on its celestial sphere, an observational rule to determine this orientation is presented. The bifurcation problem is thus solved by applying this observational rule, and consequently, {\em all} of the parameters in the general expression of the coordinate transformation from emission coordinates to inertial ones may be computed from the data received by the user of the relativistic positioning system.Comment: 10 pages, 7 figures. The version published in PRD contains a misprint in the caption of Figure 3, which is here amende

The Labour Market in Spain: Problems, Challenges and Future Trends. Policy Brief #2015/01

Spain’s economy was hit particularly hard by the financial crisis. After severe austerity measures have been implemented in recent years to contain a strong public debt increase, first signs of economic recovery are emerging. However, as SIM Europe results show, very few measures to soften the social consequences have been enacted. Spain scores second to last in the ‘Labour Market Access’ dimension of the Social Justice Index 2015, with the greatest deterioration among all EU countries compared to 2008. According to the Reform Barometer 2015, the quality of labour market reforms in Spain ranks last in the EU. With economic recovery gaining momentum, high priority should be given to ameliorating labour market access through higher education improvements, professional training, investments into R&D and promotion of high added-value industries

Capacidad de carga y efectos del nivel de protección en tres AMPs de las Islas Baleares (Mediterráneo Noroccidental)

The monitoring of fisheries target species in three marine protected areas (MPAs) located in the NW Mediterranean provided important conclusions on management effects. The abundance, occurrence and biomass of large fish showed consistent and growing trends inside the MPAs. Fish diversity was also favoured by protection. Nevertheless, spatial variance of these indicators at a medium scale was often of the same order as that caused by time between different protection levels. The carrying capacity was determined for the first time in western Mediterranean MPAs in five out of six sites studied, and in all cases it was achieved within the first five years of protection. The observed values indicate that the system of the studied MPAs is representative of the general coastal environment of the Balearic Islands, but is far from the potential of other MPAs which are considered as hot spots in other localities. Likewise, this study shows that partially protected areas can also be fairly effective if their habitats fit with those required by target species and fishing modalities are suitably regulated or banned.El seguimiento de especies de peces vulnerables a la pesca en 3 AMPs del Mediterráneo Occidental ha permitido extraer conclusiones importantes sobre los efectos de la gestión. La abundancia y ocurrencia de peces grandes así como la biomasa presentaron patrones temporales consistentes y crecientes en las AMPs. Conjuntamente al incremento de biomasa, la diversidad de peces también aumentó con la protección. Sin embargo, la varianza de estos indicadores a mediana escala espacial fue a menudo del mismo orden que la producida por el tiempo y el nivel de protección. La capacidad de carga se ha establecido por primera vez en AMPs del Mediterráneo Occidental en 5 de los 6 sitios estudiados. En todos los casos esta situación se alcanzó dentro de los primeros 5 años de protección. Los resultados indican que el sistema de AMPs estudiado es representativo de la mayor parte de las costas de Baleares pero que está lejos del potencial de otras AMPs consideradas como hot spots en otros enclaves geográficos. Asimismo, este trabajo pone de manifiesto que las áreas de reserva parcial pueden ser muy efectivas si su hábitat se ajusta al de las especies que quieren protegerse y si las modalidades de pesca restringidas o prohibidas son las adecuadas