Representation of the virtual space in extended systems – a correlation energy convergence study

We present an investigation of the convergence behaviour of the local second-order Møller-Plesset perturbation theory (MP2) correlation energy toward the canonical result for three insulating crystals with either projected atomic orbitals (PAOs) or various orthonormal representations of the virtual orbital space. Echoing recent results for finite molecular systems, we find that significantly fewer PAOs than localised orthonormal virtual orbitals are required to reproduce the canonical correlation energy. We find no clear-cut correlation between conventional measures of orbital locality and the ability of the representation to span the excitation space of local domains. We show that the PAOs of the reference unit cell span parts of the excitation space that can only be reached with distant local orthonormal virtual orbitals

708 Common and 2010 rare DISC1 locus variants identified in 1542 subjects:analysis for association with psychiatric disorder and cognitive traits

A balanced t(1;11) translocation that transects the Disrupted in schizophrenia 1 (DISC1) gene shows genome-wide significant linkage for schizophrenia and recurrent major depressive disorder (rMDD) in a single large Scottish family, but genome-wide and exome sequencing-based association studies have not supported a role for DISC1 in psychiatric illness. To explore DISC1 in more detail, we sequenced 528 kb of the DISC1 locus in 653 cases and 889 controls. We report 2718 validated single-nucleotide polymorphisms (SNPs) of which 2010 have a minor allele frequency of <1%. Only 38% of these variants are reported in the 1000 Genomes Project European subset. This suggests that many DISC1 SNPs remain undiscovered and are essentially private. Rare coding variants identified exclusively in patients were found in likely functional protein domains. Significant region-wide association was observed between rs16856199 and rMDD (P=0.026, unadjusted P=6.3 × 10-5, OR=3.48). This was not replicated in additional recurrent major depression samples (replication P=0.11). Combined analysis of both the original and replication set supported the original association (P=0.0058, OR=1.46). Evidence for segregation of this variant with disease in families was limited to those of rMDD individuals referred from primary care. Burden analysis for coding and non-coding variants gave nominal associations with diagnosis and measures of mood and cognition. Together, these observations are likely to generalise to other candidate genes for major mental illness and may thus provide guidelines for the design of future studies. © 2014 Macmillan Publishers Limited

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations

The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry

The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations

Compatibilit\ue0 tra linee elettriche di trasmissione HVDC e nuove infrastrutture ferroviarie

Lo sviluppo della rete di trasmissione europea ha un interesse strategico per incrementare la sicurezza dell'alimentazione elettrica e per garantire ai vari operatori un accesso pi\uf9 facile al mercato elettrico paneuropeo. A ci\uf2 si aggiunga che le forti opposizioni per la costruzione di nuove linee aeree in altissima tensione spingono verso un uso pi\uf9 razionale delle infrastrutture esistenti. L'articolo esamina la possibilit\ue0 di utilizzare un tunnel ferroviario di 65 km per installare una linea elettrica di potenza nominale pari a 1000 MW [1]. Lo studio (che rientra in un'analisi pi\uf9 ampia che contempla oltre all'infrastruttura ferroviaria anche quella stradale) ha preso come riferimento il collegamento tra Italia e Francia in quanto, nel caso specifico, il progetto dell'alta velocit\ue0 ferroviaria prevede la costruzione di due canne separate: conseguentemente il collegamento di potenza dovrebbe trovare collocazione all'interno di uno dei due tunnel ferroviari a differenza di altre casistiche (gi\ue0 esaminate nel caso del tunnel del Brennero [2, 3]) che prevedono invece di installare il collegamento elettrico nel tunnel pilota (o di prospezione) o in un tunnel d'emergenza. Ci\uf2 rappresenta una vera e propria sfida ingegneristica per molteplici ragioni: gli spazi disponibili, le problematiche di accesso al tunnel, i vincoli sull'esercizio e la manutenzione dovuti a quelli prioritari dell'esercizio ferroviario, la necessit\ue0 di garantire condizioni di assoluta sicurezza. Partendo dalle conclusioni dello studio di compatibilit\ue0 geometrica, che ha indagato sulle varie opzioni tecnologiche (cavi c.a. ad isolamento estruso o gassoso, cavi c.c.) all'interno di un tunnel fortemente sovraccarico di servizi, la soluzione HVDC sembra essere l'unica possibile, soprattutto per gli stringenti vincoli spaziali. Lo studio di fattibilit\ue0 individua inoltre nella configurazione bipolare con ritorno metallico quella con maggiori margini di disponibilit\ue0. Vengono quindi messe in evidenza le scelte tecniche e le problematiche emerse durante lo studio di fattibilit\ue0. In particolare: \uf0d8 le due tecnologie scelte per i cavi di polo: una pi\uf9 tradizionale con isolamento in carta impregnata a 500 kV e una pi\uf9 innovativa con isolamento in polietilene a 300 kV; \uf0d8 il cavo di ritorno metallico; \uf0d8 il calcolo delle perdite elettriche del collegamento al fine di valutarne la compatibilit\ue0 termica all'interno della galleria; \uf0d8 le problematiche legate alla sicurezza in caso di corto circuito su un cavo di polo all'interno della galleria: approccio teorico e validazione sperimentale su spezzoni di cavo a 300 kV e 450 kV; \uf0d8 l'impatto elettromagnetico considerando le due opzioni di un polo per galleria o entrambi in un'unica galleria; \uf0d8 la compatibilit\ue0 elettromagnetica tra l'alimentazione ferroviaria e il collegamento c.c. considerando la presenza di un certo contenuto armonico sul lato corrente continua e l'effetto schermante fornito dagli schermi metallici dei cavi; \uf0d8 valutazioni teoriche sul comportamento al fuoco dei cavi all'interno del tunnel. La comunit\ue0 europea ha co-finanziato tale studio nell'ambito del TEN-ENERGY Programme con il titolo "Studies for a new interconnection between France and Italy: Integration of Electricity and Rail Transport in the Lyon-Turin High Speed Railway French-Italian Tunnel"

Evidence for an electromagnon in GdMn2O5 : A multiferroic with a large electric polarization

International audienceWe report in this paper the dynamical properties of GdMn2O5 studied by inelastic neutron scattering and infrared spectroscopy assisted by ab initio calculations. Our work sheds light on the electromagnon, a magnetic mode that can be excited by an electric field. Combining spin-wave measurements, simulations, and ab initio calculations of the single-ion anisotropies and the superexchange interactions, we describe in detail themagnetic contribution to this mode. An exhaustive study of the temperature and polarization dependence of its electroactivity completes this comprehensive study of the complex GdMn2O5 system

Power transformer fire and environmental risk reduction by using natural esters

The present paper presents the main results obtained by the Italian Working Group on Natural Esters recently promoted by the University of Rome "La Sapienza", the Firefighters Authority, the Department for Geological Survey of Italy (ISPRA) and the Department of Technological Innovations, Safety of Product, Plants and Anthropic Settlements of the National Institute for Insurance against Accidents at Work (INAIL). This WG on Natural Esters was set up at the beginning of 2016 with the aim of establish the effective possibility of reducing the risks to human health and the environment, through increased spread of innovative transformers insulated with natural esters. In the paper are presented and discussed the following topics: main properties of natural esters and mineral oils; fire risk evaluation of distribution and transmission transformers, including an experimental comparison of fire behavior of natural esters and mineral insulating oils; risk evaluation and different remedial solution for leakage and spill of natural esters and mineral insulating oils

Fire simulation tests of mineral oil and natural esters transformers

This paper describes the work carried out by the Italian Institutional Working Group on Natural Esters; this Group has been promoted by the University of Roma 'La Sapienza', the National Firefighters Authority, the National Institute for Insurance against Accidents at Work (INAIL) and the Department for Geological Survey of Italy (ISPRA) with the objective of further validating the real possibility of risk mitigation for humans and environment through a more widespread use of a new generation of transformers insulated with natural ester liquids. A useful contribution to the activities of the Italian Institutional Group on Natural Esters has been also given by the participation of some of the major players in the electrical sector, such as: Italian TSO, main Distributors, Natural Ester producers and transformer manufacturers. The development of this Italian Group at international level has been the set-up of the CIGRE WG D1.68 'Natural and synthetic esters - Evaluation of the performance under fire and the impact on environment', which is actually preparing a report on this subject. The present paper reports the main results of experimental comparative fire simulations of both mineral oil and natural esters distribution transformers