s- and d-wave Symmetries in Nonadiabatic Theory of Superconductivity

High-$T_c$ superconductors have Fermi energies $E_F$ much smaller than conventional metals comparable to phonon frequencies. In such a situation nonadiabatic effects are important. A generalization of Eliashberg theory in the nonadiabatic regime has previously been shown to reproduce some anomalous features of the high-$T_c$ superconductors as for istance the enhancement of $T_c$ or the isotopic effects on $T_c$ and $m^*$. In this contribution we address the issue of the symmetry of the gap in the context of nonadiabatic superconductivity. We show that vertex corrections have a momentum structure which favours d-wave superconductivity when forward scattering is predominant. An additional increase of $T_c$ is also found.Comment: 6 pages, 3 eps figure, ijmpb-macros, proceeding of SATT10, to appear on Int. Journ. Mod. Phys.

A new procedure to analyze RNA non-branching structures

RNA structure prediction and structural motifs analysis are challenging tasks in the investigation of RNA function. We propose a novel procedure to detect structural motifs shared between two RNAs (a reference and a target). In particular, we developed two core modules: (i) nbRSSP_extractor, to assign a unique structure to the reference RNA encoded by a set of non-branching structures; (ii) SSD_finder, to detect structural motifs that the target RNA shares with the reference, by means of a new score function that rewards the relative distance of the target non-branching structures compared to the reference ones. We integrated these algorithms with already existing software to reach a coherent pipeline able to perform the following two main tasks: prediction of RNA structures (integration of RNALfold and nbRSSP_extractor) and search for chains of matches (integration of Structator and SSD_finder)

Isotope effects in the Hubbard-Holstein model within dynamical mean-field theory

We study the isotope effects arising from the coupling of correlated electrons with dispersionless phonons by considering the Hubbard-Holstein model at half-filling within the dynamical mean-field theory. In particular we calculate the isotope effects on the quasi-particle spectral weight $Z$, the renormalized phonon frequency, and the static charge and spin susceptibilities. In the weakly correlated regime $U/t \lesssim 1.5$, where $U$ is the Hubbard repulsion and $t$ is the bare electron half-bandwidth, the physical properties are qualitatively similar to those characterizing the Holstein model in the absence of Coulomb repulsion, where the bipolaronic binding takes place at large electron-phonon coupling, and it reflects in divergent isotope responses. On the contrary in the strongly correlated regime $U/t \gtrsim 1.5$, where the bipolaronic metal-insulator transition becomes of first order, the isotope effects are bounded, suggesting that the first order transition is likely driven by an electronic mechanism, rather then by a lattice instability. These results point out how the isotope responses are extremely sensitive to phase boundaries and they may be used to characterize the competition between the electron-phonon coupling and the Hubbard repulsion.Comment: 10 pages, 8 figures. The paper has been already accepted on Phys. Rev.

Nonadiabatic high-Tc superconductivity in hole-doped fullerenes

In this paper we address the possibility of high-T-c superconductivity (T(c)similar to100 K) in hypothetical hole doped C-60 within the context of the nonadiabatic theory of superconductivity. Our analysis shows that electron doped fullerenes, represented by the A(3)C(60) family, are characterized by relatively small values of the electron-phonon coupling constant lambda, which can thus be further increased by hole doping before lattice instabilities occur. In particular we show that T-c larger than 100 K are compatible in the nonadiabatic context with microscopic parameters lambda(h)similar or equal to0.5-1.0, mu(*)similar or equal to0.3-0.5 and phonon frequencies omega(ph)similar or equal to1500-2000 K. These results provide a stimulus for material engineering and optimization along the lines indicated

Relevance of multiband Jahn-Teller effects on the electron-phonon interaction in A3A_3C60_{60}

Assessing the effective relevance of multiband effects in the fullerides is of fundamental importance to understand the complex superconducting and transport properties of these compounds. In this paper we investigate in particular the role of the multiband effects on the electron-phonon (el-ph) properties of the $t_{1u}$ bands coupled with the Jahn-Teller intra-molecular $H_g$ vibrational modes in the C$_{60}$ compounds. We show that, assuming perfect degeneracy of the electronic bands, vertex diagrams arising from the breakdown of the adiabatic hypothesis, are one order of magnitude smaller than the non-crossing terms usually retained in the Migdal-Eliashberg (ME) theory. These results permit to understand the robustness on ME theory found by numerical calculations. The effects of the non degeneracy of the $t_{1u}$ in realistic systems are also analyzed. Using a tight-binding model we show that the el-ph interaction is mainly dominated by interband scattering within a single electronic band. Our results question the reliability of a degenerate band modeling and show the importance of these combined effects in the $A_3$C$_{60}$ family.Comment: 5 pages, 3 eps figure

Equity in the finance and delivery of health care: some tentative cross-country comparisons

Equity is widely acknowledged to be an important goal in the field of health care. Indeed, McLachlan and Maynard (1982) have gone so far as to suggest that' the vast majority of the population would elect for equity to be the prime consideration' (p. 556)—a view endorsed by Mooney (1986, p. 145). Several researchers have investigated how successful their own country's delivery and/or financing system is in achieving its stated equity goals. In general the strategy of these studies is to compare the current situation with some ideal or 'target* situation. Le Grand (1978), for example, in what has become a classic study in the field, compares the distributions across socio-economic groups of illness and public expenditure on health care in Britain in 1972, and concludes that the National Health Service (NHS) has failed to achieve equity in the delivery of health care

Horizontal equity in the delivery of health care

This paper offers a critical appraisal of the various methods used to date to investigate inequity in the delivery of health care. It concludes that none of the methods used to date is particularly well equipped to provide unbiassed estimates of the extent of inequity. It also concludes that Le Grand's (1978) approach is likely to point towards inequity favouring the rich even when none exists. The paper offers an alternative approach, which builds on the approaches to date but seeks to overcome their deficiencies

SAveRUNNER: an R-based tool for drug repurposing

Background: Currently, no proven effective drugs for the novel coronavirus disease COVID-19 exist and despite widespread vaccination campaigns, we are far short from herd immunity. The number of people who are still vulnerable to the virus is too high to hamper new outbreaks, leading a compelling need to find new therapeutic options devoted to combat SARS-CoV-2 infection. Drug repurposing represents an effective drug discovery strategy from existing drugs that could shorten the time and reduce the cost compared to de novo drug discovery. Results: We developed a network-based tool for drug repurposing provided as a freely available R-code, called SAveRUNNER (Searching off-lAbel dRUg aNd NEtwoRk), with the aim to offer a promising framework to efficiently detect putative novel indications for currently marketed drugs against diseases of interest. SAveRUNNER predicts drug–disease associations by quantifying the interplay between the drug targets and the disease-associated proteins in the human interactome through the computation of a novel network-based similarity measure, which prioritizes associations between drugs and diseases located in the same network neighborhoods. Conclusions: The algorithm was successfully applied to predict off-label drugs to be repositioned against the new human coronavirus (2019-nCoV/SARS-CoV-2), and it achieved a high accuracy in the identification of well-known drug indications, thus revealing itself as a powerful tool to rapidly detect potential novel medical indications for various drugs that are worth of further investigation. SAveRUNNER source code is freely available at https://github.com/giuliafiscon/SAveRUNNER.git, along with a comprehensive user guide

SARNET2 Severe Accident Phenomenology Course - January 2011

The first SARNET2 “Severe Accident Phenomenology Short Course” was organized from 10 to 14 January 2011 by CEA and UNIPI and hosted by Pisa University, with the participation of about 100 students from 20 different countries. This was a 1-week course on phenomenology, focused on disseminating the knowledge gained on severe accidents in the last two decades to students, young engineers and researchers. The goal was also to refresh participants memories after 5 years and SARNET new outcomes, with a program covering severe accident phenomenology and progression in current watercooled Gen. II NPPs, but also the different design solutions in Gen. III ones. Lecturers were experts from 8 different countries, with large skills and knowledge on Gen. II and III plants and on the progression of a severe accident. The course was open to university students with a discount fee and contributed for 3 ECTS with a strong link among SARNET2 and ENEN

SPINNAKER: an R-based tool to highlight key RNA interactions in complex biological networks

Background: Recently, we developed a mathematical model for identifying putative competing endogenous RNA (ceRNA) interactions. This methodology has aroused a broad acknowledgment within the scientific community thanks to the encouraging results achieved when applied to breast invasive carcinoma, leading to the identification of PVT1, a long non-coding RNA functioning as ceRNA for the miR-200 family. The main shortcoming of the model is that it is no freely available and implemented in MATLAB®, a proprietary programming platform requiring a paid license for installing, operating, manipulating, and running the software. Results: Breaking through these model limitations demands to distribute it in an open-source, freely accessible environment, such as R, designed for an ordinary audience of users that are not able to afford a proprietary solution. Here, we present SPINNAKER (SPongeINteractionNetworkmAKER), the open-source version of our widely established mathematical model for predicting ceRNAs crosstalk, that is released as an exhaustive collection of R functions. SPINNAKER has been even designed for providing many additional features that facilitate its usability, make it more efficient in terms of further implementation and extension, and less intense in terms of computational execution time. Conclusions: SPINNAKER source code is freely available at https://github.com/sportingCode/SPINNAKER.git together with a thoroughgoing PPT-based guideline. In order to help users get the key points more conveniently, also a practical R-styled plain-text guideline is provided. Finally, a short movie is available to help the user to set the own directory, properly