26 research outputs found

    Semiclassical and quantum behavior of the Mixmaster model in the polymer approach for the isotropic Misner variable

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    We analyze the semiclassical and quantum behavior of the Bianchi IX Universe in the Polymer Quantum Mechanics framework, applied to the isotropic Misner variable, linked to the space volume of the model. The study is performed both in the Hamiltonian and field equations approaches, leading to the surprising result of a still singular and chaotic cosmology, whose Poincar\'e return map asymptotically overlaps the standard Belinskii-Khalatnikov-Lifshitz one. In the quantum sector, we reproduce the original analysis due to Misner, within the revised Polymer approach and we arrive to demonstrate that the quantum numbers of the point-Universe still remain constants of motion. This issue confirms the possibility to have quasi-classical states up to the initial singularity. The present study clearly demonstrates that the asymptotic behavior of the Bianchi IX Universe towards the singularity is not significantly affected by the Polymer reformulation of the spatial volume dynamics both on a pure quantum and a semiclassical level.Comment: 25 pages, 10 figures. v2: more discussions/clarification adde

    Analysis of the phenotypes in the Rett Networked Database

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    Rett spectrum disorder is a progressive neurological disease and the most common genetic cause of intellectual disability in females. MECP2 is the major causative gene. In addition, CDKL5 and FOXG1 mutations have been reported in Rett patients, especially with the atypical presentation. Each gene and different mutations within each gene contribute to variability in clinical presentation, and several groups worldwide performed genotype-phenotype correlation studies using cohorts of patients with classic and atypical forms of Rett spectrum disorder. The Rett Networked Database is a unified registry of clinical and molecular data of Rett patients, and it is currently one of the largest Rett registries worldwide with several hundred records provided by Rett expert clinicians from 13 countries. Collected data revealed that the majority of MECP2-mutated patients present with the classic form, the majority of CDKL5-mutated patients with the early-onset seizure variant, and the majority of FOXG1-mutated patients with the congenital form. A computation of severity scores further revealed significant differences between groups of patients and correlation with mutation types. The highly detailed phenotypic information contained in the Rett Networked Database allows the grouping of patients presenting specific clinical and genetic characteristics for studies by the Rett community and beyond. These data will also serve for the development of clinical trials involving homogeneous groups of patient

    Indirect search for dark matter from the Galactic Center and halo with the Super-Kamiokande detector

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    We present a search for an excess of neutrino interactions due to dark matter in the form of weakly interacting massive particles (WIMPs) annihilating in the Galactic center or halo based on the data set of Super-Kamiokande-I, -II, -III and -IV taken from 1996 to 2016. We model the neutrino flux, energy, and flavor distributions assuming WIMP self-annihilation is dominant to ν ¯ ν , μ + μ − , b ¯ b , or W + W − . The excess is in comparison to atmospheric neutrino interactions which are modeled in detail and fit to data. Limits on the self-annihilation cross section ⟨ σ A V ⟩ are derived for WIMP masses in the range 1 GeV to 10 TeV, reaching as low as 9.6 × 10 − 23     cm 3   s − 1 for 5 GeV WIMPs in b ¯ b mode and 1.2 × 10 − 24     cm 3   s − 1 for 1 GeV WIMPs in ν ¯ ν mode. The obtained sensitivity of the Super-Kamiokande detector to WIMP masses below several tens of GeV is the best among similar indirect searches to date

    Nuovi documenti dall'archivio di Aristofane, figlio di Giovanni

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    Edizione di quattro ostraca conservati presso il Museo archeologico di Firenze. due greci e due copti. I primi due documenti appartengono con certezza al noto dossier del tebano Aristofane, figlio di Giovanni (sec. VIII)

    Frammento di tractoria o documento ad essa pertinente (PL III/1004)

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    Edizione di un frammento papiraceo greco di sec. VI recante con buona probabilità l'unica attestazione egiziana ad oggi nota di una tractoria

    P.Flor. i 78: una riedizione

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    riedizione di un ampio frammento di registro fiscale bizantino, con migliorie testuali ed esegetiche

    High-Flow Nasal Cannula Versus Standard Oxygen Therapy After Extubation in Liver Transplantation: A Matched Controlled Study

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    BACKGROUND: High-flow nasal cannula (HFNC) is a key component of oxygen therapy and has largely been used in patients with acute respiratory failure. We conducted a matched controlled study with the aim to compare the preventive use of oxygen therapy delivered by HFNC versus via air-entrainment mask (standard O2) after extubation in adult subjects with liver transplantation for reducing postextubation hypoxemia. METHODS: Twenty-nine subjects with liver transplantation who received HFNC after extubation (HFNC group) were matched 1:1 with 29 controls (standard O2 group) chosen from an historical group of 90 subjects admitted to the ICU during the previous 36 months. The primary outcome of the study was the incidence of hypoxemia at 1 h and 24 h after extubation. Secondary outcomes were the rate of weaning failure, ICU length of stay, and 28-d mortality. RESULTS: The incidence of hypoxemia was not significantly different between the HFNC and standard O2 groups at 1 h and 24 h after extubation. In the HFNC group, there was a trend toward a lower rate of weaning failure compared with the standard O2 group. ICU length of stay and 28-d mortality were similar in both groups. CONCLUSIONS: Early application of HFNC in the subjects with liver transplantation did not reduce the incidence of hypoxemia after extubation compared with standard O2 and did not modify the incidence of weaning failure, ICU length of stay, and 28-d mortality in this high-risk population of subjects. (ClinicalTrials.gov registration NCT03441854.
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