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SUMMARY The Gutenberg–Richter b-value is thought to be a proxy of stress conditions in the crust and therefore able to locate asperities as zones of stress concentration responsible for the nucleation of strong events. The scientific literature contains a broad range of case studies showing precursory drops of b, just before the occurrence of strong events, and subsequent rises, during the early part of aftershocks sequences. Translating these results into hazard assessment, the b-value has assumed the status of a candidate precursor to the occurrence of an imminent large event. This issue is analysed here for three major seismic sequences that occurred recently in Italy. In comparison to previous studies, this investigation indicates that the variability of b may not be a reliable indicator of stress or a significant precursor in these examples, and instead may be assigned to a combination of chance, inhomogeneities in the data and inefficiencies in estimation methodologies. Consequently, extreme caution is required when we interpret b-values both as a proxy of physical processes involved in a seismic sequence and as a precursor to the occurrence of imminent strong events.

L'INGV è Centro di Competenza per i fenomeni sismici, vulcanici e i maremoti per il Dipartimento di Protezione Civile Nazionale (DPC). Nell’ambito delle attività previste dall’Accordo Quadro DPC-INGV 2012-2021 (AQ vigente), l’INGV svolge attività di sorveglianza tecnico-scientifica sulla sismicità del territorio nazionale, sui fenomeni vulcanici e sui maremoti, finalizzata ai compiti di protezione civile, in modo ininterrotto (H24 per 365 giorni l’anno). Tale attività viene realizzata con uno specifico assetto organizzativo, che consente la trasmissione in tempo reale verso il DPC di tutte le informazioni riguardanti eventi e rischi sismici, vulcanici e da maremoto di interesse per il Dipartimento stesso. La sorveglianza sismica del territorio nazionale e delle aree limitrofe è in carico all’Osservatorio Nazionale Terremoti (ONT), insieme alle comunicazioni relative agli eventi in area mediterranea e nel mondo. La sorveglianza delle aree vulcaniche campane (Campi Flegrei, Ischia, Vesuvio) e siciliane (Etna, Stromboli, Vulcano, altre isole Eolie, Pantelleria) sono rispettivamente in carico all’Osservatorio Vesuviano (OV) e all’Osservatorio Etneo (OE). Dal gennaio 2017 è diventata ufficialmente operativa anche l’attività di monitoraggio e il Servizio di allerta dei maremoti di origine sismica (Centro Allerta Tsunami - CAT) con l’introduzione nella Sala INGV di Roma di una nuova unità di personale. In fase sperimentale, fino alla fine del 2016, e per i primi mesi di operatività, il personale per il Servizio di Allerta Tsunami è stato scelto all’interno del gruppo di turnisti che da anni svolgeva il Servizio di Sorveglianza Sismica; successivamente, è stato reclutato e formato nuovo personale in grado di svolgere entrambi i Servizi. A partire dal 2017 e nei due anni successivi sono stati attivati, quindi, i corsi per la formazione di nuovi turnisti e funzionari per i servizi di Sorveglianza Sismica e di Allerta Tsunami ed anche per i reperibili di Sala [Quintiliani et al., 2020]. La formazione del personale che partecipa al Servizio di Sorveglianza Sismica è prevista nei Piani di attività annuali relativi all’Allegato A dell’AQ vigente, tematica “Sorveglianza sismica” e quella del personale che partecipa alle attività del CAT nella tematica “Centro Allerta Tsunami (CAT)”. Inoltre, il Progetto “S.O.I.R. monitoraggio futuro” ha tra le sue finalità quella della formazione del personale delle Sale Operative INGV, essendo il WP4 “Formazione” uno dei sei working package del progetto espressamente dedicato a questo.

We present the first high-quality catalog of early aftershocks of the three mainshocks of the 2016 central Italy Amatrice-Visso-Norcia normal faulting sequence. We located 10,574 manually picked aftershocks with a robust probabilistic, non-linear method achieving a significant improvement in the solution accuracy and magnitude completeness with respect to previous studies. Aftershock distribution and relocated mainshocks give insight into the complex architecture of major causative and subsidiary faults, thus providing crucial constraints on multi-segment rupture models. We document reactivation and kinematic inversion of a WNW-dipping listric structure, referable to the inherited Mts Sibillini Thrust (MST) that controlled segmentation of the causative normal faults. Spatial partitioning of aftershocks evidences that the MST lateral ramp had a dual control on rupture propagation, behaving as a barrier for the Amatrice and Visso mainshocks, and later as an asperity for the Norcia mainshock. We hypothesize that the Visso mainshock re-activated also the deep part of an optimally oriented preexisting thrust. Aftershock patterns reveal that the Amatrice Mw5.4 aftershock and the Norcia mainshock ruptured two distinct antithetic faults 3–4 km apart. Therefore, our results suggest to consider both the MST cross structure and the subsidiary antithetic fault in the finite-fault source modelling of the Norcia earthquake.

Heparin-induced thrombocytopenia (HIT) is a severe complication of heparin therapy, characterized by thrombocytopenia and an increased risk for thrombotic complications secondary to the formation of IgG antibodies (Ab), recognizing a complex of heparin (H) and PF4. Using the 4T clinical score for HIT and the presence of heparin-associated Ab assayed by enzyme-linked immunosorbent assay and heparin-induced platelet aggregation, we define the phenotype of three groups of patients: 51 H/PF4/Ab patients with antibodies and without thrombocytopenia; 50 patients with thrombocytopenia (HIT) and 53 patients with thrombosis (HITT). In these patients we studied four polymorphisms: FcγRIIA-H131R, GpIIb/IIIa-HP-1, PECAM1-L125V (in linkage-disequilibrium with S563N and R670G), and FcγRIIIA-F158V, to understand if these variations may influence the different phenotypes of the patients. There were no difference in genotype or allele frequencies between controls and the three groups of patients. Afterward, we created a genotype score for multiple risk alleles for thrombosis considering as risk genotype FcγRIIA R/R131, HPA-1a/b, and PECAM1-V/V125. These polymorphisms were overrepresented in HITT patients, ascertained by a permutation test (10 000 replicates) p = 0.0198 for the two-single-nucleotide polymorphism (SNP) model and p = 0.0119 for the three-SNP model. The calculated odds ratio for thrombosis was 4.01[CI: 2.30-6.96] in the case of the presence of two at risk genotypes and 8.002 [CI: 4.59-13.93] if all the three at risk genotypes were present. In conclusion these polymorphisms could contribute to the risk of thrombotic complications in HIT.

A smartphone, with its integrated sensors and cpu, can aid experiments in many different areas of Physics. We show how the resonant frequencies of a pipe can be measured using a smartphone and a Bic pen., Comment: 6 pages, 3 figures, in Italian

There are still many parts of the world where most structures have been built before a sound earthquake building code was established, and where seismic retrofitting would be desirable to reduce the risk of casualties, and to mitigate economic loss from building damage. Government budgets may be switched from one department to another, but there are often circumstances when a specific national budget is ring-fenced just for expenditure for one purpose, as for seismic retrofitting. Especially in times of economic austerity, specific allocation of government funding for seismic retrofitting measures needs to be decided in a transparent, auditable, and justifiable manner. Italy is such a country, where, at the beginning of 2010, the Italian government decided to provide funds for reducing seismic risk on a medium-term time scale. The procedure for allocating these funds is under particular scrutiny because of the aftermath of the L’Aquila earthquake of April 6, 2009, which resulted in the tragic deaths of three hundred people. Court proceedings against the seismologists involved in providing advice on the short-term seismic hazard have had international repercussions. As and when another highly destructive Italian earthquake disaster occurs, legal questions may well be asked as to why the buildings which collapsed were not amongst those prioritized for retrofitting, using the designated government funds. The prospect of an official post-event enquiry over the budget allocation for retrofitting poses a challenging problem for public policy. In order to be able to justify a chosen allocation, a systematic objective method for prioritization is needed; one which allocates the fixed budget in an optimal way, maximizing the retrofitting benefit. This involves evaluating the respective costs and benefits of alternative risk mitigation actions, taking account of the time horizon for assessing the retrofitting benefits. Two time horizons are considered: a fifty-year period relating to occupation duration, and a shorter ten-year period aligned pragmatically with terms of political decision-making. The mathematical formulation of the prioritization process falls within the class of knapsack problems, which are well known in combinatorial optimization. In this paper we propose a preliminary solution to the problem for an illustrative case study of two cities of contrasting seismic hazard, with four generic classes of buildings, and two levels of retrofitting. Searching for an optimal solution turns out to be both informative and instructive, because some individual retrofit opportunities with high benefit-cost ratios may not be funded. The finding that the optimal allocation is far from obvious or intuitive makes further studies of this kind worthwhile in the future.

The Authors report three cases of ophthalmic neurosyphilis in patients who complained a visual decrease monocular. The diagnosis was performed with physical and fundus examination, electrophysiological, hemato-chemical and microbiological tests, fluorangiografy and RMN. The physical examination provided standard results about eyes interested while the fundus examination, as well as the electrofunctional and fuorangiografy examinations, showed some alterations. The sockets and encephalon RMN were normal. Moreover; the patients were submitted to specific haematic and microbiological laboratory tests which showed positivity for syphilis. To sum up all patients received an incidental diagnosis of syphilis. This trend could be attributable to an extensive use of antibiotics that changing the natural course of disease, mask clinical evidences and make them harder to diagnose.

We report a novel mutation in Factor X (FX) gene which results in a phenotype without any bleeding tendency. The proband has been found to be a compound heterozygote between a novel FX true deficiency (Gly(380)--Arg) and a previously reported dysfunctional mutation Ser(334)--Pro (FX Marsiglia). Prothrombin time (PT) and partial thromboplastin time (PTT) were moderately prolonged and were fully corrected by the addition of normal serum. Her FX activity level varied between 8% and 19% of normal according to the method used whereas the FX antigen level was 40% of the normal control value. All the exons and intron/exon junctions of the FX gene were studied using a combined approach of polymerase chain reaction and conformation sensitive gel electrophoresis. A transversion G to A in exon 8 resulting in the replacement of Gly380 by Arg was found in the proband, in the father and in a proband's brother, whereas heterozygous FX Marsiglia was present in the proband's mother and her sister. Gly380 is strictly linked to Ser379, a component of the catalytic triad. The substitution of Gly for Arg causes the introduction of a large charged amino acid which could affect the catalytic function of FX leading to secretion problem, accounting for the cross-reactive material (CRM) negative phenotype.