1,721,137 research outputs found
Optical sum rule anomalies in the cuprates: Interplay between strong correlation and electronic band structure
No full textWe theoretically analyze some of the anomalies of the optical sum rules in the high-temperature superconductors. In particular, we address the particularly strong dependence on temperature of the sum rule in the normal state. Both electron-electron correlations and the presence of a Van Hove singularity have been shown to enhance such a dependence. Here, we consider both effects simultaneously by means of dynamical mean-field theory for a two-dimensional Hubbard model with realistic parameters for different cuprates, and we find that the two effects are not cooperative, as they appear to compete with one another in the region of parameters relevant for the experiments. RI Capone, Massimo/A-7762-200
Alberto TOSCHI (a cura di), Apuleio Neosofista. Discorso per la sua statua a Cartagine (Floridum 16).
No full textGavray Marc-Antoine. Alberto TOSCHI (a cura di), Apuleio Neosofista. Discorso per la sua statua a Cartagine (Floridum 16).. In: L'antiquité classique, Tome 74, 2005. pp. 355-356
Toschi, A. — Fauna d’Italia. Vol. VII. Mammalia, Lagomorpha, Rodentia, Carnivora, Artiodactyla, Cetacea. Bologna, Calderini, 1965
No full textBourlière François. Toschi, A. — Fauna d’Italia. Vol. VII. Mammalia, Lagomorpha, Rodentia, Carnivora, Artiodactyla, Cetacea. Bologna, Calderini, 1965. In: La Terre et La Vie, Revue d'Histoire naturelle, tome 20, n°2, 1966. pp. 214-215
How to read between the lines of electronic spectra: the diagnostics of fluctuations in strongly correlated electron systems
No full textWhile calculations and measurements of single-particle spectral properties often offer the most direct route to study correlated electron systems, the underlying physics may remain quite elusive, if information at higher particle levels is not explicitly included. Here, we present a comprehensive overview of the different approaches which have been recently developed and applied to identify the dominant two-particle scattering processes controlling the shape of the one-particle spectral functions and, in some cases, of the physical response of the system. In particular, we will discuss the underlying general idea, the common threads and the specific peculiarities of all the proposed approaches. While all of them rely on a selective analysis of the Schwinger-Dyson (or the Bethe-Salpeter) equation, the methodological differences originate from the specific two-particle vertex functions to be computed and decomposed. Finally, we illustrate the potential strength of these methodologies by means of their applications the two-dimensional Hubbard model, and we provide an outlook over the future perspective and developments of this route for understanding the physics of correlated electrons
Recurrence of skin and soft tissue infections: identifying risk factors and treatment strategies
Full text linkPurpose of reviewRecurrent skin and soft tissue infections (RSSTIs) are challenging for the clinicians due to morbidity and healthcare-related costs. Here, we review updates on risk factors and management.Recent findingsRSSTIs rates range between 7 and 45%. Local and systemic conditions can favour RSSTIs, with comorbidities such as obesity, diabetes, cancer and immunosuppressive disease becoming increasingly relevant. Streptococcus spp. and Staphylococcus aures (including methicillin resistant, MRSA) are the leading causative pathogens of RSSTIs, but also Gram-negative bacteria and polymicrobial infection should be considered. To prevent recurrences, treatment of underlying predisposing factor, complete source control and appropriate antibiotic therapy are crucial. Antibiotic prophylaxis for recurrent erysipelas and decolonization for MRSA carriers demonstrated some advantages, but also long-term loss of efficacy and possible adverse effects. Clinical score and patients risk stratification could be useful tools to target prophylaxis and decolonization strategies. To reduce hospitalization rates and costs, outpatient oral and parenteral antibiotic therapy (OPAT) and long-acting antibiotics are being implemented.SummaryManagement of RSSTIs requires both preventive interventions on modifiable risk factors and pharmacological strategies, with a patient tailored approach
Absence of phase-fluctuation contribution to the low-frequency optical conductivity in d-wave superconductors at zero temperature
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Separability of dynamical and nonlocal correlations in three dimensions
No full textWhile second-order phase transitions always cause strong nonlocal fluctuations, their effect on spectral properties crucially depends on the dimensionality. For the important case of three dimensions, we show that the electron self-energy is well separable into a local dynamical part and static nonlocal contributions. In particular, our nonperturbative many-body calculations for the three-dimensional Hubbard model at different fillings demonstrate that the quasiparticle weight remains essentially momentum independent, including in the presence of overall large nonlocal corrections to the self-energy. Relying on this insight, we propose a "space-time-separated" scheme for many-body perturbation theory that is up to ten times more efficient than current implementations. Besides these far-reaching implications for state-of-the-art electronic structure schemes, our analysis will also provide guidance to the quest of going beyond them
Dynamical vertex approximation for the two-dimensional Hubbard model
No full textRecently, diagrammatic extensions of dynamical mean field theory (DMFT) have been proposed for including short- and long-range correlations beyond DMFT on an equal footing. We employ one of these, the dynamical vertex approximation (D Gamma A), and study the two-dimensional Hubbard model on a square lattice. We define two transition lines in the phase diagram which correspond, respectively, to the opening of the gap in the nodal direction and throughout the Fermi surface. Our self-energy data show that the evolution between the two regimes occurs in a gradual way (crossover) and also that at low enough temperatures the whole Fermi surface is always gapped. Furthermore, we present a comparison of our DTA calculations at a parameter set where data obtained by other techniques are available. (C) 2015 Elsevier B.V. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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