System Estimates of Cyclical Unemployment and Cyclical Output in the 15 European Union Member-States, 1961-1999

The purpose of this paper was to estimate cyclical unemployment and cyclical output in the 15 European Union member-states using a system of Phillips curve and Okun’s law equations. Treating both the NAIRU and the potential output growth rate as time varying unobserved stochastic processes, a state-space maximum likelihood estimation method - using Kalman filter where the state variables were random walks - was followed in order to estimate the 15 systems of equations. Overall, the estimated with the new approach systems of conditional equations suggested that the extent and direction of changes of cyclical unemployment and cyclical output over the period 1961-1999 is mixed across the 15 EU member states. The paper concludes that the application of “common” policies across the 15 EU member states may be questionable because of the different expected effects of these policies on the various economies.Phillips curve, Okun’s law, Kalman filter, Cyclical unemployment, Potential output growth rate, NAIRU, Europe

Quintessential Kination and Thermal Production of SUSY e-WIMPs

The impact of a kination-dominated phase generated by a quintessential exponential model on the thermal abundance of Supersymmetric (SUSY) extremely Weekly Interacting Massive Particles (e-WIMPs) is investigated. For values of the quintessential energy-density parameter on the eve of nucleosynthesis close to its upper bound, we find that: (i) the gravitino constraint is totally evaded for unstable gravitinos; (ii) the thermal abundance of stable gravitinos is not sufficient to account for the cold dark matter of the universe; (iii) the thermal abundance of axinos can satisfy the cold dark matter constraint for values of the initial (``reheating'') temperature well above those required in the standard cosmology.Comment: To appear in the proceedings of 4th International Workshop On The Dark Side Of The Universe (DSU 2008) 1-5 Jun 2008, Cairo, Egyp

Tracking Quintessence and Cold Dark Matter Candidates

We study the generation of a kination-dominated phase in the context of a quintessential model with an inverse-power-law potential and a Hubble-induced mass term for the quintessence field. The presence of kination is associated with an oscillating evolution of the quintessence field and the barotropic index. We find that, in sizeable regions of the parameter space, a tracker scaling solution can be reached sufficiently early to alleviate the coincidence problem. Other observational constraints originating from nucleosynthesis, the inflationary scale, the present acceleration of the universe and the dark-energy-density parameter can be also met. The impact of this modified kination-dominated phase on the thermal abundance of cold dark matter candidates is investigated too. We find that: (i) the enhancement of the relic abundance of the WIMPs with respect to the standard paradigm, crucially depends on the hierarchy between the freeze-out temperature and the temperature at which the extrema in the evolution of the quintessence field are encountered, and (ii) the relic abundance of e-WIMPs takes its present value close to the temperature at which the earliest extremum of the evolution of the quintessence field occurs and, as a consequence, both gravitinos and axinos arise as natural cold dark matter candidates. In the case of unstable gravitinos, the gravitino constraint can be satisfied for values of the initial temperature well above those required in the standard cosmology.Comment: Final versio

The liberalisation of maritime transport and the island regions in EU. Evidence from Greece

The liberalisation of maritime transport constitutes a substantial and vital progress not only in the maritime transport market but also in influencing the development of distant island regions. In the European Union (EU), the establishment of the legal framework and policy regarding the liberalisation is standing from the year of 1992. In Greece, the first attempt to harmonize the inevitable political and state framework was in 2001 (2932/2001 Act). Prevailing factors encumbered the liberalisation planning and implementing, mainly because of the incoherent procedures applied and the partial cover of principal issues regarding impingement of public interests and goods relative to island development. In our paper, we provide strongly support to the argument that the major initiative considering the development of island regions throughout European territory is that European Policy for the liberalisation of maritime transport should be oriented to the distinctive needs of island regions. Moreover, we provide a “road map” for completion of the liberalisation procedures. Hence, we address specific proposals and measures towards the healing of the inadequate regional development

Quintessential Kination and Cold Dark Matter Abundance

The generation of a kination-dominated phase by a quintessential exponential model is investigated and the parameters of the model are restricted so that a number of observational constraints (originating from nucleosynthesis, the present acceleration of the universe and the dark-energy-density parameter) are satisfied. The decoupling of a thermal cold dark matter particle during the period of kination is analyzed, the relic density is calculated both numerically and semi-analytically and the results are compared with each other. It is argued that the enhancement, with respect to the standard paradigm, of the cold dark matter abundance can be expressed as a function of the quintessential density parameter at the onset of nucleosynthesis. We find that values of the latter quantity close to its upper bound require the thermal-averaged cross section times the velocity of the cold relic to be almost three orders of magnitude larger than this needed in the standard scenario so as compatibility with the cold dark matter constraint is achieved.Comment: Published versio

F-Term Hybrid Inflation Followed by Modular Inflation

We consider the well motivated model of the (standard) supersymmetric F-term hybrid inflation (FHI) which can be realized close to the grand unification scale. The predicted scalar spectral index $n_s$ cannot be smaller than 0.98 and can exceed unity including corrections from minimal supergravity, if the number of e-foldings corresponding to the pivot scale $k_*=0.002/{\rm Mpc}$ is around 50. These results are marginally consistent with the fitting of the Wilkinson microwave anisotropy probe data by the standard power-law cosmological model with cold dark matter and a cosmological constant. However, $n_s$ can be reduced by restricting the number of e-foldings that $k_*$ suffered during FHI. The additional e-foldings required for solving the horizon and flatness problems can be generated by a subsequent stage of fast-roll [slow-roll] modular inflation realized by a string modulus which does [does not] acquire effective mass before the onset of modular inflation.Comment: To appear in the proceedings of the Spanish Relativity Meeting (ERE 2008) 15-20 September 2008, Salamanca, Spai