Experimental perspectives for systems based on long-range interactions

The possibility of observing phenomena peculiar to long-range interactions, and more specifically in the so-called Quasi-Stationary State (QSS) regime is investigated within the framework of two devices, namely the Free-Electron Laser (FEL) and the Collective Atomic Recoil Laser (CARL). The QSS dynamics has been mostly studied using the Hamiltonian Mean-Field (HMF) toy model, demonstrating in particular the presence of first versus second order phase transitions from magnetized to unmagnetized regimes in the case of HMF. Here, we give evidence of the strong connections between the HMF model and the dynamics of the two mentioned devices, and we discuss the perspectives to observe some specific QSS features experimentally. In particular, a dynamical analog of the phase transition is present in the FEL and in the CARL in its conservative regime. Regarding the dissipative CARL, a formal link is established with the HMF model. For both FEL and CARL, calculations are performed with reference to existing experimental devices, namely the FERMI@Elettra FEL under construction at Sincrotrone Trieste (Italy) and the CARL system at LENS in Florence (Italy)

Phase transitions of quasistationary states in the Hamiltonian Mean Field model

The out-of-equilibrium dynamics of the Hamiltonian Mean Field (HMF) model is studied in presence of an externally imposed magnetic field h. Lynden-Bell's theory of violent relaxation is revisited and shown to adequately capture the system dynamics, as revealed by direct Vlasov based numerical simulations in the limit of vanishing field. This includes the existence of an out-of-equilibrium phase transition separating magnetized and non magnetized phases. We also monitor the fluctuations in time of the magnetization, which allows us to elaborate on the choice of the correct order parameter when challenging the performance of Lynden-Bell's theory. The presence of the field h removes the phase transition, as it happens at equilibrium. Moreover, regions with negative susceptibility are numerically found to occur, in agreement with the predictions of the theory.Comment: 6 pages, 7 figure

Assessing the risk of osteonecrosis of the jaw due to bisphosphonate therapy in the secondary prevention of osteoporotic fractures

here is evidence that the use oral bisphosphonates can lead to osteronecrosis of the jaws (ONJ). Although the occurrence of ONJ appears rare among oral bisphosphonates (BPs) users, it is important to know that it exists and can be opportunely minimized. Introduction: The purpose of this study is to evaluate the association between BPs prescribed for the secondary prevention of osteoporotic fractures and the occurrence of ONJ. Methods: An Italian record linkage claims database with a target population of around 18 million individuals (6 million over 55 years of age) constituted the data source. We conducted a nested case-control study within a cohort of individuals aged 55+ years old, who were discharged from hospitals with a primary diagnosis of incident osteoporotic fracture. The date related to the discharge diagnosis of ONJ was the index date. Conditional logistic regression for matched data was fitted to estimate the odds ratio (OR) along with 95 % confidence intervals (95 % CI) for the likely association between use of BPs and the risk of ONJ. Results: Any one of the 61 ascertained cases of ONJ (incidence rate, 36.6 per 100,000 person-years) was matched to 20 controls for a total of 1120 controls. When the exposure to BPs was modeled according to recency (i.e., exposure time window prior to the index date) of use, the adjusted OR (95 % CI) for current users was 2.8 (1.3-5.9) against never users. The cumulative use of BPs has shown to increase the incidence of ONJ among patients with primary osteoporotic fractures, although not statistically significant risk has been observed. Conclusions: Although the risk of BP-related ONJ appears low in non-oncological indications, it is important to be aware that it exists and to know how it may be predicted and possibly minimized

Vlasov equation for long-range interactions on a lattice

We show that, in the continuum limit, the dynamics of Hamiltonian systems defined on a lattice with long-range couplings is well described by the Vlasov equation. This equation can be linearized around the homogeneous state and a dispersion relation, that depends explicitly on the Fourier modes of the lattice, can be derived. This allows one to compute the stability thresholds of the homogeneous state, which turn out to depend on the mode number. When this state is unstable, the growth rates are also function of the mode number. Explicit calculations are performed for the $\alpha$-HMF model with $0 \leq \alpha <1$, for which the zero mean-field mode is always found to dominate the exponential growth. The theoretical predictions are successfully compared with numerical simulations performed on a finite lattice

Risk of atrial fibrillation among bisphosphonate users: a multicenter, population-based, Italian study

Summary: Bisphosphonate treatment is used to prevent bone fractures. A controversial association of bisphosphonate use and risk of atrial fibrillation has been reported. In our study, current alendronate users were associated with a higher risk of atrial fibrillation as compared with those who had stopped bisphosphonate (BP) therapy for more than 1 year.Introduction: Bisphosphonates are widely used to prevent bone fractures. Controversial findings regarding the association between bisphosphonate use and the risk of atrial fibrillation (AF) have been reported. The aim of this study was to evaluate the risk of AF in association with BP exposure.Methods: We performed a nested case-control study using the databases of drug-dispensing and hospital discharge diagnoses from five Italian regions. The data cover a period ranging from July 1, 2003 to December 31, 2006. The study population comprised new users of bisphosphonates aged 55 years and older. Patients were followed from the first BP prescription until an occurrence of an AF diagnosis (index date, i.e., ID), cancer, death, or the end of the study period, whichever came first. For the risk estimation, any AF case was matched by age and sex to up to 10 controls from the same source population. A conditional logistic regression was performed to obtain the odds ratio with 95 % confidence intervals (CI). The BP exposure was classified into current (<90 days prior to ID), recent (91–180), past (181–364), and distant past (≥365) use, with the latter category being used as a reference point. A subgroup analysis by individual BP was then carried out.Results: In comparison with distant past users of BP, current users of BP showed an almost twofold increased risk of AF: odds ratio (OR) = 1.78 and 95 % CI = 1.46–2.16. Specifically, alendronate users were mostly associated with AF as compared with distant past use of BP (OR, 1.97; 95 % CI, 1.59–2.43).Conclusion: In our nested case-control study, current users of BP are associated with a higher risk of atrial fibrillation as compared with those who had stopped BP treatment for more than 1 year

On Nontrival Equilibria in Finitely Repeated Games

Background: Data on the effect of oral bisphosphonates (BPs) on risk of upper gastrointestinal complications (UGIC) are conflicting. We conducted a large population-based study from a network of Italian healthcare utilization databases aimed to assess the UGIC risk associated with use of BPs in the setting of secondary prevention of osteoporotic fractures.Methods: A nested case-control study was carried out within a cohort of 68,970 patients aged 45 years or older, who have been hospitalized for osteoporotic fracture from 2003 until 2005. Cases were the 804 patients who experienced hospitalization for UGIC until 2007. Up to 20 controls were randomly selected for each case. Conditional logistic regression model was used to estimate odds ratio (OR) associated with current and past use of BPs (i.e. for drug dispensation within 30 days and over 31 days prior the outcome onset, respectively) after adjusting for several covariates.Results: Compared with patients who did not use BPs, current and past users had OR (and 95% confidence interval) of 0.86 (0.60 to 1.22) and 1.07 (0.80 to 1.44) respectively. There was no difference in the ORs estimated according with BPs type (alendronate or risedronate) and regimen (daily or weekly), nor with co-therapies and comorbidities.Conclusions: Further evidence that BPs dispensed for secondary prevention of osteoporotic fractures are not associated with increased risk of severe gastrointestinal complications is supplied from this study. Further research is required to clarify the role BPs and other drugs of co-medication in inducing UGI

ESPON Italian evidence in changing Europe

Il volume, che rientra nelle attività dell’ESPON Contact Point Italia, accoglie i risultati del contributo dei Partner Italiani allo sviluppo dei progetti del Programma ESPON 2013, acronimo di European Observation Network for Territorial Development and Cohesion. I testi sintetizzano ed evidenziano, tra l’altro, le relazioni con le politiche di sviluppo regionale dell’Italia, inserendole in un quadro di cooperazione transnazionale che coinvolge 28 + 4 paesi dell’Unione europea. Affrontando aspetti della politica territoriale europea che spaziano dall’innovazione e conoscenza all’accessibilità, dal policentrismo alle aree metropolitane, dalla migrazione alla globalizzazione, gli Autori mettono in luce la posizione dell’Italia e delle regioni anche rispetto agli obiettivi fissati da Europe 2020. Uno spazio è dedicato alle esperienze regionali che hanno trovato in ESPON uno stimolo e un’occasione di confronto; come pure ai concetti che sottendono il lessico, i principi di orientamento e i nuovi modelli della pianificazione in Europa; e alle esperienze formative rivolte alle giovani generazioni e ai decision maker Il libro si inquadra nelle iniziative del Semestre di Presidenza Italiana dell’Unione europea ed è cofinanziato dal Ministero delle Infrastrutture e dei Trasporti (MIT) responsabile nazionale del Programma ESPON. E’ rivolto ai ricercatori, agli utilizzatori istituzionali, ai policy maker, ai “practioner” e ai “non specialisti”, tra cui gli studenti, affinché possano fare propri i risultati dell’impegno costante, rigoroso e rispettoso delle diversità territoriali che hanno contraddistinto, dal 2007 ad oggi, il contributo della ricerca, anche sperimentale e applicata, alla crescita della società italiana come parte integrante del sistema europeo. L’Osservatorio ESPON, per chi ancora non lo conosce, può rappresentare un viaggio nel territorio europeo, nelle sue diversità territoriali, economiche, sociali, culturali da integrare e rendere coese, sostenibili, mantenendo e sviluppando potenziali di competitività crescenti e, nel contempo, innovando e diffondendo nuovi modi, metodologie, strumenti e prassi per fare del territorio un bene comune e condiviso. Dati, riferimenti e raccomandazioni politiche utili alla crescita del Paese completano il quadro. Presentazione del Ministro delle Infrastrutture, On. Maurizio Lupi Postfazione del Direttore della Coordination Unit del Programma ESPON, Peter MehlbyeThe book is part of the activities of ESPON Contact Point Italy. It includes the results of the contribution of the Italian partners in the development of projects under the ESPON 2013 Programme, which stands for European Observation Network for Territorial Development and Cohesion. The texts summarise and highlight, among other things, the relations with the regional development policies of Italy, placing them in a framework of transnational cooperation involving the 28 + 4 EU Countries. Addressing aspects of European territorial policy, ranging from innovation and knowledge accessibility, from the polycentrism to metropolitan areas, from migration to globalization, the authors highlight the position of Italy and of regions also in relation to the objectives set by Europe 2020. A place is devoted to the regional experiences that in the ESPON found a stimulus and an opportunity for discussion, as well as to the concepts behind the vocabulary, to the principles of guidance, and new planning models in Europe, and to the training experiences aimed at the younger generations and the decision makers The book forms part of the initiatives of the Italian Presidency of the European Union and is co-financed by the Ministry of Infrastructure and Transportation (MIT) in charge of the national ESPON Programme. It is aimed at researchers, institutional users, policy makers, at "practitioners" and "non-specialists" including students, so that they can make use of the results of the constant and rigorous work also respectful of the territorial diversities that have characterized the experimental and applied research since 2007, so contributing to the growth of Italian society as an integral part of the European system. The ESPON Monitoring Centre, for those who still do not know, can be a journey into the European territory, its territorial, economic, social, cultural diversities to integrate and make cohesive and sustainable, by maintaining and developing the increasing potentials of competitiveness and, at the same time, by innovating and disseminating new ways, methodologies, tools and practices to make the territory a common and shared good. Data, references and useful policy recommendations to the growth of the country are also included in the book. Presentation by the Minister of Infrastructure, Mr. Maurizio Lupi Afterword by the Director of the Coordination Unit ESPON Programme , Peter Mehlby

Out-of-equilibrium phase re-entrance(s) in long-range interacting systems

Systems with long-range interactions display a short-time relaxation toward quasistationary states (QSSs) whose lifetime increases with system size. The application of Lynden-Bell\u2019s theory of \u201cviolent relaxation\u201d to the Hamiltonian Mean Field model leads to the prediction of out-of-equilibrium first- and second-order phase transitions between homogeneous (zero magnetization) and inhomogeneous (nonzero magnetization) QSSs, as well as an interesting phenomenon of phase re-entrances. We compare these theoretical predictions with direct N-body numerical simulations. We confirm the existence of phase re-entrance in the typical parameter range predicted from Lynden-Bell\u2019s theory, but also show that the picture is more complicated than initially thought. In particular, we exhibit the existence of secondary re-entrant phases: we find unmagnetized states in the theoretically magnetized region as well as persisting magnetized states in the theoretically unmagnetized region. We also report the existence of a region with negative specific heats for QSSs both in the numerical and analytical caloric curves