Neutrinos self interactions in Supernovae

Oscillations of neutrino emerging from a supernova core are studied. In this extremely high density region neutrino self interactions induce collective flavor transitions. When collective transitions are decoupled from matter oscillations, as for our chosen matter profile, an analytical interpretation of the collective effects is possible, by means of a mechanical analogy with a spherical pendulum. For inverted neutrino hierarchy the neutrino propagation can be divided in three regimes: synchronization, bipolar oscillations, and spectral split. Our simulation shows that averaging over neutrino trajectories does not alter the nature of these three regimes.Comment: 6 pages, 7 figures, to appear in the Proceedings of the 43rd Rencontres de Moriond EW session, La Thuile, Italy, 1-8 March 200

Fast flavor conversions of supernova neutrinos: Classifying instabilities via dispersion relations

Supernova neutrinos can exhibit a rich variety of flavor conversion mechanisms. In particular, they can experience "fast" self-induced flavor conversions almost immediately above the core. Very recently, a novel method has been proposed to investigate these phenomena, in terms of the dispersion relation for the complex frequency and wave number ($\omega$,$k$) of disturbances in the mean field of the $\nu_e\nu_x$ flavor coherence. We discuss a systematic approach to such instabilities, originally developed in the context of plasma physics, and based of the time-asymptotic behavior of the Green's function of the system. Instabilities are typically seen to emerge for complex $\omega$, and can be further characterized as convective (moving away faster than they spread) and absolute (growing locally), depending on $k$-dependent features. Stable cases emerge when $k$ (but not $\omega$) is complex, leading to disturbances damped in space, or when both $\omega$ and $k$ are real, corresponding to complete stability. The analytical classification of both unstable and stable modes leads not only to qualitative insights about their features but also to quantitative predictions about the growth rates of instabilities. Representative numerical solutions are discussed in a simple two-beam model of interacting neutrinos. As an application, we argue that supernova and binary neutron star mergers exhibiting a "crossing" in the electron lepton number would lead to an absolute instability in the flavor content of the neutrino gas.Comment: (v2, revised version: 25 pages, 15 pdf figures. Minor changes. Figures improved. Matches the version published on PRD

Pandemics and international security: The outlook for NATO

The Covid-19 pandemic has had a multi-faced impact on Western societies, quickly moving from a health crisis to a broader phenomenon deeply affecting the socio-economic and political landscapes. Multilateral institutions had to cope with unprecedented challenges, while the pandemic exposed existing patterns of great power competition applied to the global race for personal protective equipment, vaccines, and relevant raw materials. Nations – at least initially – seemed to abandon well- established patterns of cooperation to revert to national solutions to this very global challenge. Global economy experienced disruptions in trade and in the functioning of the Global Value Chains (GVCs), as well as significant redistributions of wealth through drastic downs and ups of Gross Domestic Product (GDP) across the world. In less than two years, the pandemic experience prompted a deep revision of standard views on critical interdependencies, diversification, resilience of GVCs and security of supplies. When it comes to international security, the pandemic mostly acted as a catalyst of existing trends, such as the geopolitical competition between the United States (US) and China – which has worsened, also due to the outbreak of the disease. As for the armed forces, in several NATO countries including France, Italy and the United Kingdom (UK), they have been called to operate in support of civilian authorities to deal with Covid-related aspects such as field hospitals, logistics, law enforcement, Covid tests or the vaccines’ distribution – and NATO itself provided support through its bodies such as the Euro-Atlantic Disaster Response Coordination Centre (EADRCC)

Global constraints on absolute neutrino masses and their ordering

Within the standard three-neutrino framework, the absolute neutrino masses and their ordering (either normal, NO, or inverted, IO) are currently unknown. However, the combination of current data coming from oscillation experiments, neutrinoless double beta decay searches, and cosmological surveys, can provide interesting constraints for such unknowns in the sub-eV mass range, down to O(0.1) eV in some cases. We discuss current limits on absolute neutrino mass observables by performing a global data analysis, that includes the latest results from oscillation experiments, neutrinoless double beta decay bounds from the KamLAND-Zen experiment, and constraints from representative combinations of Planck measurements and other cosmological data sets. In general, NO appears to be somewhat favored with respect to IO at the level of ~2 sigma, mainly by neutrino oscillation data (especially atmospheric), corroborated by cosmological data in some cases. Detailed constraints are obtained via the chi^2 method, by expanding the parameter space either around separate minima in NO and IO, or around the absolute minimum in any ordering. Implications for upcoming oscillation and non-oscillation neutrino experiments, including beta-decay searches, are also discussed.Comment: 17 pages, including 3 tables and 11 figure

Relations between the United States of America and Italy in the post-Cold War period: a defense-industrial perspective

This article analyzes U.S.-Italian relations after 1989 from a defence-industrial perspective. It argues that the concentration and internationalization of the Italian defence industry, particularly through the creation of Finmeccanica, influenced bilateral relations by introducing a new element into defence industrial cooperation between the two countries. Military procurement programs involving American and Italian governments and industries, based on several memorandums of understanding, have become an important component of transatlantic relations. In turn, these programs are influenced by the broader military and political relations between the United States and Italy, which have been particularly intense regarding Italy’s contribution to U.S.-led crisis management operations in Europe, Central Asia and the greater Mediterranean. The paper argues that there is a two-way relationship between defence industrial cooperation and politico-military cooperation.Cet article présente une analyse des relations entre les États-Unis d’Amérique et l’Italie depuis 1989 vues sous l’angle de l’industrie de la défense. La concentration et le développement international de l’industrie italienne de la défense, avec en particulier la création de Finmeccanica, a fait évoluer la relation bilatérale en introduisant un élément nouveau dans la coopération industrielle entre les États-Unis d’Amérique et l’Italie. Les programmes de fournitures militaires auxquels participent les gouvernements et industriels américains et italiens se basent sur plusieurs accords-cadres et sont devenus un élément important des relations transatlantiques. Cet élément est également influencé par les relations bilatérales militaires et politiques. Il s’agit de relations intenses marquées par la participation de l’Italie à des opérations de gestion de crise en Europe, Asie centrale ainsi que dans la région méditerranéenne. En conclusion, l’article montre comment s’articule une relation à double sens dans laquelle la dimension de coopération dans l’industrie de la défense et celle politico-militaire se correspondent

Space: Exploring NATO’s Final Frontier

Space has become increasingly vital to the security of the Euro-Atlantic region, as acknowledged by 2022 NATO Strategic Concept, presenting the international community with new challenges as it grows more contested, congested and competitive. Allies must enhance cooperation to address these evolving challenges, particularly those arising from potential military activities in space. A cooperation to focus on three critical areas: the multi-purpose applications of space, the increasing number of actors and systems, and the increasingly rapid technological advancements. NATO must strategically evaluate how to sustain its advantage in space, paralleling its strengths in other operational domains. A more united approach would help to deter adversaries, protect allied space assets, and secure an operational edge. This publication explores three key issues: the global space environment and NATO’s strategic posture, the Alliance’s space capabilities and decision-making processes, and the implications of space threats for NATO’s deterrence and defence

A multilevel theoretical study to disclose the binding mechanisms of gold(III) bipyridyl compounds as selective aquaglyceroporin inhibitors

Structural studies have paved the avenue to a deeper understanding of aquaporins (AQPs), small ancient proteins providing efficient transmembrane pathways for water, small uncharged solutes such as glycerol, and possibly gas molecules. Despite the numerous studies, their roles in health and disease remain to be fully disclosed. The recent discovery of AuIII complexes as potent and selective inhibitors of aquaglyceroporin isoforms paves the way to their possible therapeutic application. The binding of the selective human AQP3 inhibitor, the cationic complex [Au(bipy)Cl2]+ (Aubipy), to the protein channel has been investigated here by means of a multi-level theoretical workflow that includes QM, MD and QM/MM approaches. The hydroxo complex was identified as the prevalent form of Aubipy in physiological media and its binding to AQP3 studied by MD. Both non-covalent and coordinative Aubipy–AQP3 adducts were simulated to probe their role in the modulation of water channel functionality. The electronic structures of representative Aubipy–AQP3 adducts were then analysed to unveil the role played by the metal moiety in their stabilisation. This study spotlights the overall importance of three key aspects for AQP3 inhibition: 1) water speciation of the AuIII complex, 2) stability of non-covalent adducts and 3) conformational changes induced within the pore by the coordinative binding of AuIII. The obtained results are expected to orient future developments in the design of isoform-selective AuIII inhibitors

Indocyanine green clearance test in liver transplantation: defining cut-off levels for graft viability assessment during organ retrieval and for the prediction of post-transplant graft function recovery - the Liver Indocyanine Green (LivInG) Trial Study Protocol

Introduction Viability assessment of the graft is essential to lower the risk of liver transplantation (LT) failure and need for emergency retransplantation, however, this still relies mainly on surgeon's experience. Post-LT graft function recovery assessment is also essential to aid physicians in the management of LT recipients and guide them through challenging decision making. This study aims to trial the use of indocyanine green clearance test (IGT) in the donor as an objective tool to assess graft viability and in the recipient to assess graft function recovery after LT.Methods and analysis This is an observational prospective single-centre study on consecutive liver transplant donors and recipients.Primary objective To determine the capability of IGT of predicting graft viability at the time of organ retrieval. Indocyanine green will be administered to the donor and the plasma disappearance rate (PDR) measured using the pulsidensitometric method. Some 162 IGT donor procedures will be required (alpha, 5%; beta, 20%) using an IGT-PDR cut-off value of 13% to achieve a significant discrimination between viable and non-viable grafts.Secondary objective IGT-PDR will be measured at different time-points in the LT recipient: during the anhepatic phase, after graft reperfusion, at 24 hours, on day 3 and day 7 after LT. The slope of IGT values from the donor to the recipient will be evaluated for correlation with the development of early allograft dysfunction.Ethics and dissemination This research protocol was approved by Fondazione Policlinico Universitario Agostino Gemelli IRCCS Ethics Committee (reference number: 0048466/20, study ID: 3656) and by the Italian National Transplant Center (CNT) (reference number: Prot.11/ CNT2021). Liver recipients will be required to provide written informed consent. Results will be published in international peer-reviewed scientific journals and presented in congresses