Spectral weight function for the half-filled Hubbard model: a singular value decomposition approach

The singular value decomposition technique is used to reconstruct the electronic spectral weight function for a half-filled Hubbard model with on-site repulsion $U=4t$ from Quantum Monte Carlo data. A two-band structure for the single-particle excitation spectrum is found to persist as the lattice size exceeds the spin-spin correlation length. The observed bands are flat in the vicinity of the $(0,\pi),(\pi,0)$ points in the Brillouin zone, in accordance with experimental data for high-temperature superconducting compounds.Comment: 4 pages, Revtex

The inverse Laplace transform as the ultimate tool for transverse mass spectra

New high statistics data from the second generation of ultrarelativistic heavy-ion experiments open up new possibilities in terms of data analysis. To fully utilize the potential we propose to analyze the $m_\perp$-spectra of hadrons using the inverse Laplace transform. The problems with its inherent ill-definedness can be overcome and several applications in other fields like biology, chemistry or optics have already shown its feasability. Moreover, the method also promises to deliver upper bounds on the total information content of the spectra, which is of big importance for all other means of analysis. Here we compute several Laplace inversions from different thermal scenarios, both analytically and numerically, to test the efficiency of the method. Especially the case of a two component structure, related to a possible first order phase transition to a quark gluon plasma, is closer investigated and it is shown that at least a signal to noise ratio of $10^4$ is necessary to resolve two individual components.Comment: 13 pages (PostScript, including figures), BNL-NTHES

Hardening a Soft Budget Constraint Through 'Upward Devolution' to a Supranational Institution: The Case of Italian State-Owned Firms and the European Union

Public enterprises, Soft budget constraint, State aid, European integration, Italy, Federalism

Reflection in and on nursing practices- how nurses reflect and develop knowledge and skills during their nursing practice

Introduction: This paper present some theoretical foundations for reflection and also present some findingsfrom some studies including nurses’ reflections in and on nursing practice in various areas of nursing care.Aims: The aim of this paper was to critically discuss and analyze the application of reflection to nursing practiceand how it could become visible and understandable.Method: A secondary analysis was performed on some studies whereas the author had been involved in. Thissecondary analysis on all data focused on identifying reflection in nursing practice.Results: Data was abstracted and analyzed in order to making reflection in nursing practice visible. The resultsshow that reflection in nursing practice could be identified as reflection on action, reflection in action andreflection as self-discovering. Sometimes the nurses made good caring activities by intuition; they made someactions that they by experiences knew will function, but they had difficulties to verbalize this, in other words;they have what we call silent knowledge.Conclusion: Using reflections can access our theories in use so enabling others to learn. In this way the risk oftaking practice for granted has the potential to be reduced. So what nurses’ do- can be explored and shared –nurses can share and develop knowledge and experiences- nurses will be able to learn from each other as well asfrom ourselves