The role of non-local exchange in the electronic structure of correlated oxides

We present a systematic study of the electronic structure of several prototypical correlated transition-metal oxides: VO2, V2O3, Ti2O3, LaTiO3, and YTiO3. In all these materials, in the low-temperature insulating phases the local and semilocal density approximations (LDA and GGA) of density-functional theory yield a metallic Kohn-Sham band structure. Here we show that, without invoking strong-correlation effects, the role of non-local exchange is essential to cure the LDA/GGA delocalization error and provide a band-structure description of the electronic properties in qualitative agreement with the experimental photoemission results. To this end, we make use of hybrid functionals that mix a portion of non-local Fock exchange with the local LDA exchange-correlation potential. Finally, we discuss the advantages and the shortcomings of using hybrid functionals for correlated transition-metal oxides.Comment: submitte

Low-energy excitations in strongly correlated materials: A theoretical and experimental study of the dynamic structure factor in V2O3

PACS number(s): 71.45.Gm, 71.15.−m, 71.30.+h.-- et al.This work contains an experimental and theoretical study of the dynamic structure factor at large momentum transfer |Q|∼4 Å−1 of the strongly correlated transition-metal oxide V2O3. We focus in particular on the transitions between d states that give rise to the spectra below 6 eV. We show that the main peak in this energy range is mainly due to t2g→egσ transitions, and that it carries a signature of the phase transition between the paramagnetic insulator and the paramagnetic metal that can already be understood from the joint density of states calculated at the level of the static local density approximation. Instead, in order to obtain theoretical spectra that are overall similar to the measured ones, we have to go beyond the static approximation and include at least crystal local field effects. The latter turn out to be crucial in order to eliminate a spurious peak and hence allow a safe comparison between theory and experiment, including an analysis of the strong anisotropy of the spectra.Use of the Advanced Photon Source at Argonne National Laboratory was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. We are grateful for support by ETSF-I3 Grant No. 211956. Computer time was granted by IDRIS (544). F.I. also acknowledges financial support from the CEA program Transversal Nanosciences and M.G. from the European Research Council Advanced Grant DYNamo (ERC-2010-AdG Proposal No. 267374), Spanish Grants No. FIS2011-65702-C02-01 and No. PIB2010US-00652, ACI-Promociona (ACI2009-1036), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT-319-07), Consolider nanoTHERM (Grant No. CSD2010-00044), and European Commission projects CRONOS (280879-2 CRONOS CPFP7) and THEMA (FP7-NMP-2008-SMALL-2, 228539).Peer reviewe

Role of nonlocal exchange in the electronic structure of correlated oxides

We present a systematic study of the electronic structure of several prototypical correlated transition-metal oxides: VO2, V2O3, Ti2O3, LaTiO3, and YTiO3. In all these materials, in the low-temperature insulating phases the local and semilocal density approximations (LDA and GGA, respectively) of density-functional theory yield a metallic Kohn-Sham band structure. Here we show that, without invoking strong-correlation effects, the role of nonlocal exchange is essential to cure the LDA/GGA delocalization error and provide a band-structure description of the electronic properties in qualitative agreement with the experimental photoemission results. To this end, we make use of hybrid functionals that mix a portion of nonlocal Fock exchange with the local LDA exchange-correlation potential. Finally, we discuss the advantages and the shortcomings of using hybrid functionals for correlated transition-metal oxides.Financial support was provided by Spanish MEC (Grants No. FIS2011-65702-C02-01 and No. PIB2010US-00652), ACI-Promociona (Grant No. ACI2009-1036), Grupos Consolidados UPV/EHU del GobiernoVasco (GrantsNo. IT-319-07), and the European Research CouncilAdvanced GrantDYNamo (ERC-2010-AdG -Proposal No. 267374). Computational time was granted by i2basque and BSC “Red Española de Supercomputación.”Peer Reviewe

Successful implementation of discrete event simulation: the case of an Italian emergency department

This paper focuses on the study of a practical management problem faced by a healthcare {\it emergency department} (ED) located in the north of Italy. The objective of our study was to propose organisational changes in the selected ED, which admits approximately 7000 patients per month, aiming at improving key performance indicators related to patient satisfaction, such as the waiting time. Our study is based on a design thinking process that adopts a {\it discrete event simulation} (DES) model as the main tool for proposing changes. We used the DES model to propose and evaluate the impact of different improving scenarios. The model is based on historical data, on the observation of the current ED situation, and information obtained from the ED staff. The results obtained by the DES model have been compared with those related to the existing ED setting, and then validated by the ED managers. Based on the results we obtained, one of the tested scenarios was selected by the ED for implementation.Comment: 24 pages, 8 figures and 4 table

Tell Me What You Waste and I’ll Tell You Who You Are: An Eight-Country Comparison of Consumers’ Food Waste Habits

Using an original survey conducted in eight countries in 2021 (Canada, China, Germany, Italy, Russia, Spain, the UK, and the USA), this study explored the relationship between household food waste and dietary habits through a cross-country comparative perspective. In total, 8000 questionnaires were recorded from samples representative of the adult population of each country through an online survey conducted between the 13th and the 24th of August. The questionnaires were developed from the Waste Watcher International Observatory on Food and Sustainability, an international study of the social, behavioral, and lifestyle dynamics behind household food waste. The relationships between the per capita self-reported amount of food waste (expressed in kilocalories) and self-declared dietary habits (traditional, healthy and sustainable, vegetarian, smart, and confused) were estimated using multiple linear regression models. The results showed that smart diets are associated with higher values of food waste in Canada, Spain, the UK, and the USA. Vegetarian diets are associated with lower food waste values in China, Germany, the UK, and the USA, but not in Italy, Russia, and Spain. The share of the population adopting a smart diet was, on average, 2.7% of the sample; therefore, interventions for food waste reduction should focus on these specific types of consumers, who are often associated with larger amounts of food waste

Laboratorio di ristorazione sostenibile. Rilevazione nelle scuole. Protocollo di ricerca per l’implementazione di uno studio controllato randomizzato nelle scuole primarie dell’Emilia-Romagna

Il Laboratorio di Ristorazione Sostenibile è un tavolo di lavoro partecipato con l’obbiettivo di migliorare la sostenibilità integrata nel servizio di ristorazione collettiva ed in particolare quella scolastica. Il Laboratorio si occupa di definire pasti più sostenibili a livello di consumo e di scelta delle forniture, ridurre lo spreco alimentare e incentivare la donazione delle eccedenze nelle mense collettive attraverso una serie di interventi. Il Laboratorio si pone dunque l’obiettivo di valutare l’efficacia di un intervento nelle mense scolastiche regionali, per ridurre lo spreco alimentare degli alunni e delle alunne delle classi terze che frequentano il servizio. Capire quali interventi possono portare a una diminuzione dello spreco, in particolare quello di verdure, può infatti portare il duplice beneficio da una parte di aumentare la sostenibilità generale dei servizi e all’altra, influenzare positivamente il profilo nutrizionale del pasto. L’intervento consisterà in una modifica di servizio del pasto, cioè nell'anticipare il contorno di verdura inserendolo come prima portata. Questo documento contiene il protocollo di ricerca per l’implementazione di uno studio controllato randomizzato

Deliverable 3.2 0FLW interventions

The CHORIZO project aims to improve the understanding of the impact of social norms on behaviours related to food waste generation. This document starts from the list of actions against Food Loss and Waste (FLW) collected within the CHORIZO project (Deliverable 1.2). It establishes the foundation for the conceptualization of interventions in relation to social norms and 'what-if' scenarios with a perspective of modelling effective 0FLW interventions. This work emphasises the importance of targeted and customised interventions that include considerations on specific context-related social norms. A pivotal aspect in behavioural change interventions involves recognizing diverse social roles and settings. Here, we define the concept of social roles as expected behavioural patterns in specific contexts, exploring potential conflicts within or between these roles. In the context of the six Case Studies of the CHORIZO project, this work explores the relevant social norms within and beyond each setting, their targets groups and networks of influence. Furthermore, this report introduces potential 'what-if' scenarios emerging in the Case Studies, highlighting possible awareness-raising interventions, economic incentives and 'nudging' strategies related to social norms for 0FLW interventions. The importance of the co-design process is highlighted for the definition of possible settings (e.g., in-home settings, out-of-home settings and alternative settings) for the modelling of interventions, basing this segmentation on the similarities with the case studies in which to model interventions. In summary, this work presents a new conceptualization for behavioural interventions in FLW reduction, integrating the identification and exploitation of social norms and social roles in the settings of their influence. This report serves as a basis for upcoming modelling activities, paving the way for a deeper understanding of how social norms influence food waste generation or reduction within the CHORIZO project

Deliverable 3.1 Conceptual framework for behavioural change understanding

CHORIZO aims to improve the understanding about how social norms (rules and expectations that are socially enforced) influence behaviour related to food waste generation. In order to provide effective interventions for food loss and waste (FLW) actions, the project conducts a comprehensive analysis and construction of behavioural intervention model building. Deliverable 3.1 outlines the conceptual framework for behavioural change understanding in the CHORIZO project. This work aims at setting out the theoretical framework which represents the starting point for the modelling activities, which will focus on the effects of interactions among food supply chain actors and the influence of social norms towards zero food losses and wastes (FLW). The theoretical framework will be here presented by first outlining the complexity underpinning social systems – and food systems more specifically – and the methods available to investigate them Then, the MOA and HUMAT behavioural frameworks will be presented: the former considers food waste as an unintended consequence of iterative decisions, adaptation and behaviours driven both by internal and external factors, the latter explores agents’ behavioural decision mechanisms. The following section will provide an operational definition of social norms. Finally, the last section will supply a set of challenges and attention points to be considered when incorporating MOA and HUMAT into agent-based models and pave the way forward for the understanding of how social norms influence the generation or reduction of food waste. The document starts with an introduction on the overall project objectives and structure and highlights the framework we propose for understanding and exploring behavioural change in the CHORIZO project. In the following chapters (2 to 6), complex social systems, social norms, and model construct are explained. The document ends with a conclusion and steps to follow to ensure timely attainment of the project’s objectives

Longevity of Replaced ICD/CRT-D

Longevity of Replaced ICD/CRT-D Introduction The longevity of defibrillators (ICD) is extremely important from both a clinical and economic perspective. We studied the reasons for device replacement, the longevity of removed ICD, and the existence of possible factors associated with shorter service life. Methods and Results Consecutive patients who underwent ICD replacement from March 2013 to May 2015 in 36 Italian centers were included in this analysis. Data on replaced devices were collected. A total of 953 patients were included in this analysis. In 813 (85%) patients the reason for replacement was battery depletion, while 88 (9%) devices were removed for clinical reasons and the remaining 52 because of system failure (i.e., lead or ICD generator failure or a safety advisory indication). The median service life was 5.9 years (25th–75th percentile, 4.9–6.9) for single- and dual-chamber ICD and 4.9 years (25th–75th percentile, 4.0–5.7) for CRT-D. On multivariate analysis, the factors CRT-D device, SC/DC ICD generator from Biotronik, percentage of ventricular pacing, and the occurrence of a system failure were positively associated with a replacement procedure. By contrast, the device from Boston Scientific was an independent protective factor against replacement. Considerable differences were seen in battery duration in both ICD and CRT-D. Specifically, Biotronik devices showed the shortest longevity among ICD and Boston Scientific showed the longest longevity among CRT-D (log-rank test, P < 0.001 for pairwise comparisons). Conclusion Several factors were associated with shorter service life of ICD devices: CRT-D, occurrence of system failure and percentage of ventricular pacing. Our results confirmed significant differences among manufacturers

Curcumin-Based β-Diketo Ligands for Ga3+: Thermodynamic Investigation of Potential Metal-Based Drugs

Curcumin is known for its therapeutic properties; among these, antioxidant, anti-inflammatory and anti-cancer ones stand out. Besides, curcumin metal complexes have shown widespread application in medicine and can be exploited as lead structures for developing metal-based drugs. Unfortunately, curcumin is poorly bioavailable, mainly due to its instability in physiological conditions; this weakness is tightly connected to the presence of the β-diketo moiety undergoing tautomeric equilibrium. Stability and metal-chelating ability can be tuned by modulating the electronic effects and steric hindrance close to the β-diketo moiety; in addition, formation of a metal complex shifts the tautomeric equilibrium towards the β-keto–enol form and increases stability in biological media. Among the metals used in clinical therapy, gallium nitrate has shown to have significant antitumor activity against non-Hodgkin lymphoma and bladder cancer, thus indicating that gallium-based drugs have potential for further development as antineoplastic agents with improved therapeutic activity. Curcuminoids have demonstrated high affinity for gallium(III), allowing the formation of stable positively charged M:L 1:2 β-diketonate complexes that benefit from the therapeutic activity of both the metal and the ligand. Seven new curcumin derivatives were synthesized and completely characterized. The new derivatives retain the solvent-dependent keto–enol tautomerism, with the prevalence of the diketo form in aqueous solution. Enhanced stability in simulated physiological conditions was observed in comparison to the lead compound curcumin. The presence of Ga3+ anticipates the dissociation of the enolic proton, allowing chelate complex formation, and simultaneously it shifts the tautomeric equilibrium towards the keto–enol form. A complete 1H/13C NMR and UV–Vis study was performed to define the metal-to-ligand stoichiometry ratio and the overall stability constants. In addition, we demonstrated that some of the derivatives have increased antiproliferative activity on colon cancer cells compared to curcumin and antioxidant properties. On the whole, the synthesized curcumin-based molecules may act as new gallium(III) chelators with improved stability with respect to curcumin and could open interesting perspectives for the development of novel therapeutic agents for cancer