Falloff of the Weyl scalars in binary black hole spacetimes

The peeling theorem of general relativity predicts that the Weyl curvature scalars Psi_n (n=0...4), when constructed from a suitable null tetrad in an asymptotically flat spacetime, fall off asymptotically as r^(n-5) along outgoing radial null geodesics. This leads to the interpretation of Psi_4 as outgoing gravitational radiation at large distances from the source. We have performed numerical simulations in full general relativity of a binary black hole inspiral and merger, and have computed the Weyl scalars in the standard tetrad used in numerical relativity. In contrast with previous results, we observe that all the Weyl scalars fall off according to the predictions of the theorem.Comment: 7 pages, 3 figures, published versio

The Method of Images in Cosmology

31 pages, 18 figures31 pages, 18 figuresWe apply the method of images to the exact initial data for cosmological models that contain a number of regularly arranged discrete masses. This allows us to join cosmological regions together by throats, and to construct wormholes in the initial data. These wormholes allow for the removal of the asymptotically flat "flange" regions that would otherwise exist on the far side of black holes. The method of images also provides us with a way to investigate the definition of mass is cosmology, and the cosmological consequences of the gravitational interaction energies between massive objects. We find evidence that the interaction energies within clusters of massive objects do indeed appear to contribute to the total energy budget in the cosmological regions of the space-time

Neuropatia uditiva: incidenza e caratteristiche cliniche in neonati a rischio

INTRODUZIONE La neuropatia uditiva (NU), entità nosografica di recente individuazione, costituisce un’importante causa di ipoacusia di grado variabile dal lieve al severo, ad insorgenza sia nella primissima infanzia che nell’età giovanile, raramente nell’anziano. È riconducibile ad alterazioni di alcune componenti della via uditiva, tra cui le cellule cocleari ciliate interne (le esterne sono caratteristicamente risparmiate), le loro sinapsi con le fibre afferenti del nervo acustico o il nervo acustico stesso. L’eziologia, fatta eccezione per le forme riconducibili a mutazioni del gene OTOF (codificante per l’otoferlina, una proteina espressa dalle cellule ciliate interne cocleari), è stata posta in relazione con differenti fattori di rischio. In particolare, diversi studi hanno evidenziato una maggiore incidenza di NU tra i neonati ricoverati in UTIN o esposti, in epoca perinatale, a particolari condizioni quali iperbilirubinemia, anossia, patologie infettive, farmaci ~ 239 ~ ototossici. MATERIALI E METODI Dato il caratteristico profilo audiologico la diagnosi necessita della registrazione contemporanea delle OAEs (presenti in quanto integre le cellule ciliate esterne) e delle risposte ABR che risultano alterate, desincronizzate o addirittura irriconoscibili. Si rileva anche l’assenza del riflesso stapediale, sia ipsi che controlateralmente. RISULTATI Il nostro studio ha rilevato, in un campione di 110 bambini ricoverati in UTIN per un periodo > 5 giorni, 15 soggetti con deficit uditivo, tra i quali sono stati individuati 4 casi (26,6%) con profilo audiologico compatibile con diagnosi di NU.Gli autori descrivono le caratteristiche audiologiche ed eziologiche legate a suddetti pazienti paragonando l’incidenza della neuropatia uditiva in UTIN, il grado della sordità, la mono-bilateralità, i fattori di rischio e l’iter riabilitativo più idoneo con i dati riportati in letteratura. CONCLUSIONI La neuropatia uditiva, essendo causa di ipoacusia, può compromettere lo sviluppo del linguaggio e necessita di una diagnosi tempestiva per poter adottare le opportune misure riabilitative. In considerazione della necessità di esecuzione contemporanea di OAEs e dell’ABR ai fini di una corretta diagnosi, oltre che dei costi associati a quest’ultima metodica si raccomanda la valutazione dei potenziali evocati uditivi nei neonati ricoverati in UTIN e nei soggetti esposti a fattori di rischio più frequentemente associati a NU

Reduction of multidrug-resistant (Mdr) bacterial infections during the covid-19 pandemic: a retrospective study

Multidrug-resistant (MDR) organisms are emerging as some of the main healthcare prob-lems worldwide. During the COVID-19 pandemic, several Infection Prevention and Control (IPC) measures have been adopted to reduce nosocomial microorganism transmission. We performed a case–control study to identify if the incidence of MDR bacterial infections while using pandemic-related preventive measures is lower than in previous years. From 2017 to 2020, we monitored hospital discharges over a four-month period (P #) (1 March to 30 June) in St. Andrea Hospital, Rome. In total, we reported 1617 discharges. Pearson’s chi-squared test was used to identify significant differences. A value of p ≤ 0.05 was considered statistically significant. A significant reduction in the incidence of total MDR bacterial infections was observed during the pandemic compared to in prepandemic years (p < 0.05). We also found a significantly higher incidence of MDR bacterial infections in COVID-19 departments compared with other medical departments (29% and 19%, respectively), with extended-spectrum β-lactamase Klebsiella pneumoniae as the pathogens presenting the highest increase. This study demonstrates that maintaining a high level of preventive measures could help tackle an important health problem such as that of the spread of MDR bacteria

A quasi-static approach to structure formation in black hole universes

JD and TC both acknowledge support from the STFC under grant STFC ST/N504257/1

TREATMENT OF TINNITUS AND DIZZINESS ASSOCIATED VERTEBROBASILAR INSUFFICIENCY WITH A FIXED COMBINATION OF CINNARIZINE AND DIMENHYDRINATE

Seventy-eight consecutive subjects, 43 males and 35 females, ranging from 43 to 87 years of age suffering from dizziness and/or tinnitus due to vertebrobasilar insufficiency without other central nervous system diseases were treated with fixed combination of cinnarizine and dimenhydrinate two times a day and for two months. Data were collected considering the following parameters: age, sex, vestibular symptoms (unsteadiness, staggering, tendency to fall, swaying, vertigo due to change of position, bowing, walking, eye movements), headache, tinnitus, impaired hearing and aural fullness. Patients evaluated their vertigo symptoms and/or tinnitus intensities using a graded 3- point visual analog scale ranging from I (no symptoms) to 3 (strong symptoms) and their impact of life with classical tinnitus handicap inventory (THI) and dizziness handicap inventory (DHI) at first appointment, during the treatment and after therapy. The results of THI and DHI evidenced a statistical significant improvement either for tinnitus (t = 3.57; p<0.001) and for vestibular symptoms (t = 4.12; p<0.001); in particular at the final examination, of the 62 patients suffered from tinnitus, the 38.71% (24 cases) did not present the disorder while of the vestibular symptoms; unsteadiness and staggering both evidenced in 65/78 subjects (83.33%) at the beginning of the therapy, disappeared in the 43.08%. In conclusion dual action of the treatment showed improvement of tinnitus and dizziness symptoms, which was confirmed either by symptoms' reduction and by THI and DHI score