Emery vs. Hubbard model for cuprate superconductors: a Composite Operator Method study

Within the Composite Operator Method (COM), we report the solution of the Emery model (also known as p-d or three band model), which is relevant for the cuprate high-Tc superconduc- tors. We also discuss the relevance of the often-neglected direct oxygen-oxygen hopping for a more accurate, sometimes unique, description of this class of materials. The benchmark of the solution is performed by comparing our results with the available quantum Monte Carlo ones. Both single- particle and thermodynamic properties of the model are studied in detail. Our solution features a metal-insulator transition at half filling. The resulting metal-insulator phase diagram agrees qual- itatively very well with the one obtained within Dynamical Mean-Field Theory. We discuss the type of transition (Mott-Hubbard (MH) or charge-transfer (CT)) for the microscopic (ab-initio) parameter range relevant for cuprates getting, as expected a CT type. The emerging single-particle scenario clearly suggests a very close relation between the relevant sub-bands of the three- (Emery) and the single- band (Hubbard) models, thus providing an independent and non-perturbative proof of the validity of the mapping between the two models for the model parameters optimal to describe cuprates. Such a result confirms the emergence of the Zhang-Rice scenario, which has been recently questioned. We also report the behavior of the specific heat and of the entropy as functions of the temperature on varying the model parameters as these quantities, more than any other, depend on and, consequently, reveal the most relevant energy scales of the system.Comment: 20 pages, 19 figure

"Zombie" or active? An alternative explanation to the properties of star-forming galaxies at high redshift

Star-forming galaxies at high redshift show anomalous values of infrared excess, which can be described only by extremizing the existing relations between the shape of their ultraviolet continuum emission and their infrared-to-ultraviolet luminosity ratio, or by constructing \textit{ad-hoc} models of star formation and dust distribution. We present an alternative explanation, based on unveiled AGN activity, to the existence of such galaxies. In fact, the presence of a weak AGN configures as a natural scenario in order to explain the observed spectral properties of such high-$z$ objects in terms of a continuum slope distribution rather than altered infrared excesses, due to the different shape of the AGN continuum emission with respect to quiescent galaxies. To this aim, we directly compare the infrared-to-ultraviolet properties of high-redshift galaxies to those of known categories of AGN (quasars and Seyferts). We also infer the characteristics of their possible X-ray emission. We find a strong similarity between the spectral shapes and luminosity ratios of AGN with the corresponding properties of such galaxies. In addition, we derive expected X-ray fluxes that are compatible with energetics from AGN activity. We conclude that a moderate AGN contribution to the UV emission of such high-$z$ objects is a valid alternative to explain their spectral properties. Even the presence of an active nucleus in each source would not violate the expected quasar statistics. Furthermore, we suggest that the observed similarities between anomalous star-forming galaxies and quasars may provide a benchmark for future theoretical and observational studies on the galaxy population in the early Universe.Comment: 13 pages, 7 figures, 4 tables, accepted for publication in A&

A GIS-based model to assess electric energy consumptions and usable renewable energy potential in Lazio region at municipality scale

The ongoing energy transition processes need a rapprochement between the places of energy production and consumption with the aim of creating innovative and integrated territorial models. Consequentially, models and strategies for increasing the use of local and renewable energy sources (RES) play a key rule for enhancing energy independence and sustainability of the considered areas. The main objective of this study is to analyse the energy system of the Lazio Region in Italy, comparing electricity consumptions and production from renewable sources at municipality scale. In order to estimate the electricity consumptions and the local production by RES, the main sectors of electricity consumption together with the potential of the available RES for the electricity production have been analysed. The obtained results pinpointed the main critical aspects of the Lazio region, that are mainly focalized in the city of Rome and in the most densely inhabited municipalities. Furthermore, research outputs provide an overall framework on the regional RES potential and allowed the formulation of proposals aimed at overcoming the identified criticalities and increasing the share of electricity production from renewables. Finally, the research approach could be replicated in other areas, providing a useful process for decision makers and stakeholders

Energy use in residential buildings: Impact of building automation control systems on energy performance and flexibility

This work shows the results of a research activity aimed at characterizing the energy habits of Italian residential users. In detail, by the energy simulation of a buildings sample, the opportunity to implement a demand/response program (DR) has been investigated. Italian residential utilities are poorly electrified and flexible loads are low. The presence of an automation system is an essential requirement for participating in a DR program and, in addition, it can allow important reductions in energy consumption. In this work the characteristics of three control systems have been defined, based on the services incidence on energy consumptions along with a sensitivity analysis on some energy drivers. Using the procedure established by the European Standard EN 15232, the achievable energy and economic savings have been evaluated. Finally, a financial analysis of the investments has been carried out, considering also the incentives provided by the Italian regulations. The payback time is generally not very long: depending on the control system features it varies from 7 to 10 years; moreover, the automation system installation within dwellings is a relatively simple activity, which is characterized by a limited execution times and by an initial expenditure ranging in 1000 € to 4000 €, related to the three sample systems

Issues of energy retrofitting of a modern public housing estates. The ‘Giorgio Morandi’ complex at Tor Sapienza, Rome, 1975-1979

Energy retrofitting of historical residential buildings represents today an interesting challenge of the building sector. This is true especially in Italy where great part of the national buildingstock dates back to pre-modern and modern times and, especially, to the decades between the 1960s and the 1980s. Most of these buildings, in fact, offerthermal performances that are inadequate to current requirements in terms of energy efficiency, human comfort as well as to seismic safety. This study focuses on the energy retrofitting of public housing estatessuch as the“Giorgio Morandi” complex at Tor Sapienza in Rome. The upgrading of this complex is outlined, taking into account issues of energy saving but, also, constraints related to the historical values of the buildings. Intervention options able to improve energy efficiency are therefore foreseeable only in strict observance of cultural heritage values, which entails a deep analysis and survey of the existence in order to identify respectful, correct and feasiblesolutions

Energy Retrofit of a Historic Building Using Simplified Dynamic Energy Modeling

Energy retro-commissioning of historical buildings is an important challenge that implies both historic-artistic and technological aspects concerning the improvement in energy efficiency and comfort. A critical analysis of each possibility is essential in order to preserve the balance between efficiency and architecture. The research focuses on a historical building owned by ANCE (Associazione Nazionale Costruttori Edili), situated in Rome in the Nomentano district. Retrofitting hypothesis were made in order to improve HVAC systems, building's envelope and building's management, always respecting its architectural features. An energy audit has been done in order to evaluate the possibilities. The first step of the study consisted of a measure campaign conducted by Avvenia to know more about the actual use of the building. Next, a dynamic simplified energy modeling of the building has been built using the software Archi Energy. This allowed to preview the effect of modifications on the HVAC and envelope systems. Although starting from an original medium energy performance, simulations showed that it would be possible to reach a further reduction of energy needs by making simple changes in the management/controls domain and, with higher costs, by upgrading envelope components. This study shows that a correct approach can lead to both relevant energetic results and the conservation of architectural characteristics of historical buildings

Deontological morality can be experimentally enhanced by increasing disgust. A transcranial direct current stimulation study

Previous studies empirically support the existence of a distinctive association between deontological (but not altruistic) guilt and both disgust and obsessive-compulsive (OC) symptoms. Given that the neural substrate underlying deontological guilt comprises brain regions strictly implicated in the emotion of disgust (i.e. the insula), the present study aimed to test the hypothesis that indirect stimulation of the insula via transcranial direct current stimulation (tDCS) would enhance disgust and morality in the deontological domain. A randomized, sham-controlled, within-subject design was used. Thirty-seven healthy individuals (25 women) underwent 15-min anodal and sham tDCS over T3 in two different days, while their heart rate (HR) was recorded to derive measures of parasympathetic nervous system activity (HR variability; HRV). After the first 10-min of sham or active tDCS stimulation, participants were asked to 1) complete a series of 6-item words that could be completed with either a disgust-related word (cleaning/dirtiness) or neutral alternatives; 2) rate how much a series of vignettes, each depicting a behavior that violated a specific moral foundation, were morally wrong. Levels of trait anxiety, depression, disgust sensitivity, scrupulosity, and altruism as well as pre- and post- stimulation momentary emotional states were assessed. Compared to the sham condition, after active stimulation of T3 a) HRV significantly increased and participants b) completed more words in terms of cleaning/dirtiness and c) reported greater subjective levels of disgust, all suggesting the elicitation of the emotion of disgust. Although the results are only marginally significant, they point to the absence of difference between the two experimental conditions for moral vignettes in the altruistic domain (i.e., animal care, emotional and physical human care), but not in the deontological domain (i.e., authority, fairness, liberty, and sacrality), where vignettes were judged as more morally wrong in the active compared to the sham condition. Moreover, scores on the OCI-R correlated with how much vignettes were evaluated as morally wrong in the deontological domain only. Results preliminarily support the association between disgust and morality in the deontological domain, with important implications for OC disorder (OCD). Future studies should explore the possibility of decreasing both disgust and morality in patients with OCD by the use of non-invasive brain stimulation techniques

From Time to Time: A Constructivist Approach to Sociality in Learning

[EN] Under the current financial pressures, tertiary education increasingly looks towards corporate sector to import its model of management and efficiency. While benefits of this model can be seen in practice, in regard to staff and facilities management and financial viability, its impact on teaching and learning caused a disruption to the very core of tertiary education, eroding sociality in learning and opportunity for sharing knowledge and values. Capacity to work in teams and ability to critically solve problems by collaborating and sharing insights and informations, are skills students are expected to gain during their studies. The development of these skills to their fullest using Design Thinking approach, however, is currently not widely supported, albeit desirable,[1] in the present education context which is addressing the efficiency of time management by reducing contact time, increasing student/staff ratio and shifting towards integrated and mass education modes of delivery. While this presentation is not disputing the existing model, it responds to its current challenges proposing a stronger integration of different factors contributing to learning.Tthe aim is to present a collaborative working model as a way of bridging ‘the missing link between theoretical findings [on holistic and interdisciplinary learning] and demands by pedagogy science’[2]. Such a model is envisioned to encourage sociality in learning and strategize space/time/experience management, ultimately enhancing knowledge and value sharing. [1] Ability to solve ‘wicked problems’ as supported by Design Thinks is becoming more attractive to the tertiary sector as it promotes ‘holistic modes of constructivist learning in projects’ (Sheer et al 17 (3), 8). [2] Sheer et al 17 (3), 8http://ocs.editorial.upv.es/index.php/HEAD/HEAD18Mancini, F.; Glusac, T. (2018). From Time to Time: A Constructivist Approach to Sociality in Learning. Editorial Universitat Politècnica de València. 1567-1576. https://doi.org/10.4995/HEAD18.2018.8255OCS1567157

Prestazioni energetiche degli edifici: le norme UNI TS 11300-3/4

In attuazione della direttiva 2009/28/CE, sulla promozione dell’uso dell’energia da fonte rinnovabile, è stato emanato il Decreto Legislativo n.28 del 3/3/2011. Il decreto fornisce interessanti novità riguardanti i nuovi edifici o gli edifici sottoposti a ristrutturazioni rilevanti, con l’obiettivo di limitare i consumi di energia primaria dell’edificio attraverso sistemi edificio-impianti efficienti ed impiegando fonti rinnovabili di energia. Le prescrizioni contenute devono intendersi come requisito minimo, su tutto il territorio nazionale, con la conseguenza che tutti gli atti normativi regionali o comunali devono essere adeguati entro 180 giorni a quanto indicato. Per la prima volta, tra gli usi energetici dell’edificio, in termini di energia primaria, è inclusa la climatizzazione estiva, che dovrà essere in parte soddisfatta tramite il ricorso a fonti rinnovabili di energia. La norma UNI TS 11300-3 specifica le modalità di calcolo del fabbisogno di energia primaria e dei rendimenti per la stagione estiva; l’applicazione di tale norma sarà di seguito illustrata con riferimento a casi specifici, evidenziandone i punti salienti ed alcune criticità. Il decreto, inoltre, stabilisce che “energia da fonti rinnovabili” è l’energia proveniente da fonti rinnovabili non fossili, vale a dire energia eolica, solare, aerotermica, geotermica, idrotermica e oceanica, idraulica, biomassa, gas di discarica, gas dai processi di depurazione e biogas. La norma UNI TS 11300-4 riguarda l’utilizzo di energie rinnovabili e di altri metodi di generazione per riscaldamento di ambienti e preparazione acqua calda sanitaria; tale norma sarà nel seguito illustrata con riferimento alle parti ritenute più interessanti. Altra novità del decreto è il ruolo del teleriscaldamento, equiparato alle fonti rinnovabili, nel momento in cui consente il pieno soddisfacimento dei fabbisogni per riscaldamento ed acqua calda sanitaria. Il calcolo per il teleriscaldamento può essere effettuato mediante la UNI TS 11300-4