Are Ideal Measurements of Real Scalar Fields Causal?

Half a century ago a local and (seemingly) causally consistent implementation of the projection postulate was formulated for local projectors in Quantum Field Theory (QFT) by utilising the basic property that spacelike local observables commute. This was not the end of the story for whether projective, or ideal measurements in QFT respect causality. In particular, the causal consistency of ideal measurements was brought into question by Sorkin 20 years later using a scenario previously overlooked. Sorkin's example, however, involved a non-local operator, and thus the question remained whether ideal measurements of local operators are causally consistent, and hence whether they are physically realisable. Considering both continuum and discrete spacetimes such as causal sets, we focus on the basic local observables of real scalar field theory -- smeared field operators -- and show that the corresponding ideal measurements violate causality, and are thus impossible to realise in practice. We show this using a causality condition derived for a general class of update maps for smeared fields that includes unitary kicks, ideal measurements, and approximations to them such as weak measurements. We discuss the various assumptions that go into our result. Of note is an assumption that Sorkin's scenario can actually be constructed in the given spacetime setup. This assumption can be evaded in certain special cases in the continuum, and in a particularly natural way in Causal Set Theory. In such cases one can then freely use the projection postulate in a causally consistent manner. In light of the generic acausality of ideal measurements, we also present examples of local update maps that offer causality-respecting alternatives to the projection postulate as an operationalist description of measurement in QFT

Dynamical Henneaux-Teitelboim Gravity

We consider a modified gravity model which we call "dynamical Henneaux-Teitelboim gravity" because of its close relationship with the Henneaux-Teitelboim formulation of unimodular gravity. The latter is a fully diffeomorphism-invariant formulation of unimodular gravity, where full diffeomorphism invariance is achieved by introducing two additional non-dynamical fields: a scalar, which plays the role of a cosmological constant, and a three-form whose exterior derivative is the spacetime volume element. Dynamical Henneaux-Teitelboim gravity is a generalization of this model that includes kinetic terms for both the scalar and the three-form with arbitrary couplings. We study the field equations for the cases of spherically symmetric and homogeneous, isotropic configurations. In the spherically symmetric case, we solve the field equations analytically for small values of the coupling to obtain an approximate black hole solution. In the homogeneous and isotropic case, we perturb around de Sitter space to find an approximate cosmological background for our model.Comment: 10 pages, 2 figure

A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes

dentification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined T1D+T2D GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 subjects with diabetes (18,582 with DKD). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, P = 4.5 x 10(-8)) associated with microalbuminuria in European T2D case subjects. However, no replication of this signal was observed in Asian subjects with T2D or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously reported DKD signals, except for those at UMOD and PRKAG2, both associated with estimated glomerular filtration rate. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk variant discovery for DKD.Peer reviewe

Linguistic integration of "new minority groups". Comparative study between Italy and England

reservedL’obiettivo di questo documento è fare un’analisi, attraverso una prospettiva diacronica, delle politiche di integrazione linguistica guardando innanzitutto in generale al ruolo dell’Unione Europea in questo processo e successivamente focalizzandosi su due paesi: l’Italia e l’Inghilterra. Il soggetto di questo studio sono le “nuove minoranze” ovvero i cittadini non europei che, a partire dalla seconda metà del Novecento e con diverse motivazioni, sono emigrati in Europa. Questa categoria comprende al suo interno un gruppo eterogeneo di persone tra cui migranti economici, rifugiati e richiedenti asilo ma anche adulti, bambini e adolescenti, tutti con bisogni linguistici diversi. La conoscenza della lingua è considerata una delle abilità fondamentali per potersi integrare all’interno della società di arrivo; con questa consapevolezza, tutti i paesi europei hanno a loro modo sviluppato le proprie politiche di integrazione ovvero iniziative volte ad aiutare i migranti adulti ad acquisire o migliorare le competenze linguistiche necessarie ma anche programmi e curricula per riuscire a integrare correttamente gli studenti con background migratorio all’interno del sistema educativo. Allo stesso tempo però, la conoscenza della lingua rappresenta anche un requisito necessario per poter entrare in un paese, ottenere un permesso di soggiorno di lunga durata o la cittadinanza; allo scopo di testare queste capacità sono quindi stati introdotti dei test linguistici di vari livelli che rappresentano un’arma a doppio taglio in quanto possono diventare una barriera all’ingresso e uno strumento di selezione ma anche un incentivo all’integrazione grazie anche ai corsi messi a disposizione per prepararsi al loro svolgimento. Infine l’integrazione deve essere concepita come un processo bilaterale in cui lo stato e le persone immigrate, attraverso uno sforzo comune, collaborano non solo per raggiungere l’integrazione linguistica di quest’ultime ma anche per preservare e valorizzare la loro lingua madre in quanto valore positivo per l’intera società.The objective of the paper is to analyse linguistic integration policies from a diachronic perspective firstly looking at the role of the European Union and then focusing on two countries: Italy and England. The subject of this study is “new minorities” meaning non-European citizens that, for different reasons moved to Europe starting from the second half of the twentieth century; This category includes a heterogeneous group of people: economic migrants, refugees, asylum seekers but also both adults and children or adolescents, each of them with different linguistic needs. As language proficiency is one of the essential skills needed for integrating into the country of arrival, every country has developed, at different levels, its integration policy meaning initiatives to help adult migrants acquire or improve their linguistic skills and to successfully integrate ethnic students into the education system. On the other hand, linguistic skills are one of the requisites required either to enter, obtain an indefinite leave to remain or citizenship; to test these competencies, European nations introduced language tests of various levels that are considered a double-edged sword as they can become a barrier to entry or an instrument of selection but also an encouragement to learn the language given the language courses offered as preparation. Finally, integration is a bilateral process meaning that immigrants and the country of arrival should collaborate not only to achieve linguistic integration but also to preserve and valorise their mother tongues which represent a positive asset for the whole society

Anti-senescence compounds: A potential nutraceutical approach to healthy aging

The desire of eternal youth seems to be as old as mankind. However, the increasing life expectancy experienced by populations in developed countries also involves a significantly increased incidence of the most common age-related diseases (ARDs). Senescent cells (SCs) have been identified as culprits of organismal aging. Their number rises with age and their senescence-associated secretory phenotype fuels the chronic, pro-inflammatory systemic state (inflammaging) that characterizes aging, impairing the regenerative ability of stem cells and increasing the risk of developing ARDs. A variegated class of molecules, including synthetic senolytic compounds and natural compounds contained in food, have been suggested to possess anti-senescence activity. Senolytics are attracting growing interest, and their safety and reliability as anti-senescence drugs are being assessed in human clinical trials. Notably, since SCs spread inflammation at the systemic level through pro-oxidant and pro-inflammatory signals, foods rich in polyphenols, which exert antioxidant and anti-inflammatory actions, have the potential to be harnessed as "anti-senescence foods" in a nutraceutical approach to healthier aging. We discuss the beneficial effects of polyphenol-rich foods in relation to the Mediterranean diet and the dietary habits of long-lived individuals, and examine their ability to modulate bacterial genera in the gut