Non-commutative waves for gravitational anyons

We revisit the representation theory of the quantum double of the universal cover of the Lorentz group in 2+1 dimensions, motivated by its role as a deformed Poincar\'e symmetry and symmetry algebra in (2+1)-dimensional quantum gravity. We express the unitary irreducible representations in terms of covariant, infinite-component fields on curved momentum space satisfying algebraic spin and mass constraints. Adapting and applying the method of group Fourier transforms, we obtain covariant fields on (2+1)-dimensional Minkowski space which necessarily depend on an additional internal and circular dimension. The momentum space constraints turn into differential or exponentiated differential operators, and the group Fourier transform induces a star product on Minkowski space and the internal space which is essentially a version of Rieffel's deformation quantisation via convolution.Comment: 36 pages, 2 figures; minor corrections and additional references (version to appear in Letters in Mathematical Physics

Prompt dipole radiation in fusion reactions

The prompt gamma ray emission was investigated in the 16A MeV energy region by means of the 36,40Ar+96,92Zr fusion reactions leading to a compound nucleus in the vicinity of 132Ce. We show that the prompt radiation, which appears to be still effective at such a high beam energy, has an angular distribution pattern consistent with a dipole oscillation along the symmetry axis of the dinuclear system. The data are compared with calculations based on a collective bremsstrahlung analysis of the reaction dynamics

Evidence of dynamical dipole excitation in the fusion-evaporation of the 40Ca +152Sm heavy system

The excitation of the dynamical dipole mode along the fusion path was investigated for the first time in the formation of a heavy compound nucleus in the A ∼ 190 mass region. The compound nucleus was formed at identical conditions of excitation energy and spin from two entrance channels: the charge-asymmetric 40 Ca + 152 Sm and the nearly charge-symmetric 48 Ca + 144 Sm at E lab = 11 and 10.1 MeV / nucleon, respectively. High-energy γ rays and light charged particles were measured in coincidence with evaporation residues by means of the MEDEA multidetector array (Laboratori Nazionali del Sud, Italy) coupled to four parallel plate avalanche counters. The charged particle multiplicity spectra and angular distributions were used to pin down the average excitation energy, the average mass, and the average charge of the compound nucleus. The γ -ray multiplicity spectrum and angular distribution related to the nearly charge-symmetric channel were employed to obtain new data on the giant dipole resonance in the compound nucleus. The dynamical dipole mode excitation in the charge-asymmetric channel was evidenced, in a model-independent way, by comparing the γ -ray multiplicity spectra and angular distributions of the two entrance channels with each other. Calculations of the dynamical dipole mode in the 40 Ca + 152 Sm channel, based on a collective bremsstrahlung analysis of the reaction dynamics, are presented. Possible interesting implications in the superheavy-element quest are discussed

Automated Monitoring of Soil Respiration: an Improved Automatic Chamber System

We designed, constructed and tested an automated chamber system for continuously monitoring soil respiration. Our objective was to design a system that would permit monitoring of CO2 efflux rates over long time periods without altering microclimate inside the chamber. The measuring principle is based on the measurement of the increase in CO2 concentration within an automated chamber in a fixed amount of time using a non linear regression method. The chamber operates by closing over the soil in response to a control signal and remains closed for a fixed amount of time. In this way, the chamber allows normal drying and wetting of the soil between measurements. We report results that show the reliability of soil CO2 efflux measurements in comparison with Li-Cor 6400. The system holds great potential for long term continuous measurements campaigns in natural environments

Cambiamenti nel regime pluviometrico in ecosistemi mediterranei: il progetto MIND

Changes in rainfall patterns in Mediterranean ecosystems: the MIND project. Will Mediterranean terrestrial ecosystems be affected by the expected changes in precipitation regimes? If so, by how much and in which direction? These questions are at the basis of the research performed in context of the EU MIND project, whose key objectives were: i) to investigate the potential effects of increasing drought on Mediterranean terrestrial ecosystems at the process, ecosystem and regional scales and ii) to assess ecosystem vulnerability to changes in rainfall patterns. A network of experimental study sites has been created in Portugal, Spain, France and Italy, where field manipulations alter the amount of water available to the ecosystem. The most up-to-date methods of ecophysiology, micrometeorology, soil ecology and remote sensing have been used to elucidate the mechanisms that regulate the response of vegetation and soil to changes in water availability. This information is providing the basis for the implementation and validation of simulation models capable of predicting the drought response of Mediterranean terrestrial ecosystems, and their vulnerability to future climate change, on a larger scale. The out-coming results are elucidating how water availability affects plant ecophysiological processes, the dynamics of soil carbon and the overall exchange of mass and energy between the land and the atmosphere. This paper focuses on some of the important, yet preliminary, results on C and energy fluxes that have been obtained at the large scale troughfall manipulation experiment (Tolfa, Italy), in a forest dominated by Arbutus unedo L

Reaction dynamics for the system (17)F+(58)Ni at near-barrier energies

Charged reaction products originated from the interaction of the loosely bound radioactive ion beam (17)F (S(p) = 600 keV) with the proton-shell closed (58)Ni target were measured at two colliding energies slightly above the Coulomb barrier. The collected data were analyzed within the framework of the optical model to deduce the reaction cross section and to investigate the role played by inelastic excitations, transfer channels, and the breakup process (17)F --> (16)O + p at near-barrier energies. The reaction cross section at the lower (17)F energy showed a moderate enhancement (similar to 20%) with respect to that of the system (16)O + (58)Ni. At this energy direct reaction channels were also found to be more relevant than those for the reaction induced from the tightly bound projectile (16)O on the same target. Both features could be strongly related to the very low binding energy of the (17)F valence proton.Physical Review