230 research outputs found
Dust collapse in asymptotic safety: a path to regular black holes
Regular black hole spacetimes are obtained from an effective Lagrangian for
Quantum Einstein Gravity. The interior matter is modeled as a dust fluid, which
interacts with the geometry through a multiplicative coupling function denoted
as . The specific functional form of is deduced from
Asymptotically Safe gravity, under the key assumption that the Reuter fixed
point remains minimally affected by the presence of matter. As a consequence
the gravitational coupling vanishes at high energies. The static exterior
geometry of the black hole is entirely determined by the junction conditions at
the boundary surface. Consequently, the resulting global spacetime geometry
remains devoid of singularities at all times. This result offers a novel
perspective on regular black holes in Asymptotically Safe gravity.Comment: 6 pages, 4 figure
Updated Meta-Analysis of Randomized Trials Comparing Safety and Efficacy of Intraoperative Defibrillation Testing with No Defibrillation Testing On Implantable Cardioverter-Defibrillator Implantation
Introduction: There is an ongoing debate regarding the need to conduct intraoperative defibrillation testing (DFT) at the time of implantable cardioverter-defibrillator (ICD) implantation. To provide sufficiently strong evidence for the feasibility of omitting intraoperative DFT in clinical practice, we conducted a meta-analysis of randomized controlled trials (RCT) comparing patients with DFT and no-DFT.Methods: We systematically searched Medline (via PubMed), ClinicalTrial.gov, the Cochrane Central Register of Controlled Trials, and Embase for studies evaluating DFT vs. no-DFT on ICD implantation with regard to total mortality and arrhythmic death, efficacy of first and any appropriate shock in interrupting ventricular tachycardia (VT)/ventricular fibrillation (VF), and procedural adverse events. Effect estimates [risk ratio (RR) with 95% confidence intervals (CI)] were pooled using the random-effects model.Results: Our meta-analysis included 4 RCTs comprising 3770 patients (1896 with DFT and 1874 without DFT). Total mortality (RR = 1.00, 95% CI 0.86â1.17; P = 0.98) and arrhythmic death (RR = 1.60, 95% CI 0.46-5.59: P = 0.46) were not statistically different. Both first (RR = 0.94, 95% CI 0.89â0.98; P = 0.004) and any appropriate ICD shock (RR = 0.97, 95% CI 0.95â1.00; P = 0.02) significantly increased the rate of VT/VF interruption in the group with no-DFT in comparison with DFT. Finally, the incidence of adverse events was lower in no-DFT patients (RR = 1.23; 95% CI 1.00â1.51; P = 0.05).Conclusions: The practice of DFT (as opposed to no-DFT) did not yield benefits in mortality or the overall rate of conversion of VT/VT. Moreover, a slightly higher incidence of perioperative adverse events was observed in the DFT group
ASTRONOMICAL CALIBRATION OF THE SERRAVALLIAN/TORTONIANCASE PELACANI SECTION (SICILY, ITALY)
We performed a cyclostratigraphic study of a sedimentary sequence (Case Pelacani section) outcropping in the south-eastern margin of Sicily (Italy) and covering the Upper Serravallian/Lower Tortonian stratigraphic interval. Calcareous plankton biostratigraphic data reported in another paper proved that all the sequence of bio-events generally reported from just below and above the S/T boundary is present in the section. They allowed a detailed correlation with the Gibliscemi section. Preliminary paleomagnetic data suggest that a secondary remagnetization component prevents the recognition of the correct sequence of paleomagnetic chrons along the studied interval. The sedimentary record has been compared, on the basis of an integrated calcareous plankton biostratigraphy, with that of the Gibliscemi section. Cyclostratigraphic analysis of the lithological patterns recognized throughout the succession and the application of spectral methodologies to the abundance fluctuations of the planktonic foraminifer Globigerinoides quadrilobatus highlighted the presence in the signal of the classic Milankovitch frequencies (precession, obliquity and eccentricity). Correlation of the lithological patterns and of the different frequency bands extracted by numerical filtering from the faunal record with the same components modulating the insolation curve provided an astronomic calibration of the sedimentary record and, consequently, a precise age for all the calcareous plankton bioevents recognized throughout the studied interval. 
The large- limit of the chiral condensate from twisted reduced models
We compute the large- limit of the QCD chiral condensate on the lattice
using twisted reduced models, and performing controlled continuum and chiral
extrapolations. We perform two different calculations: one consists in
extracting the chiral condensate from the quark mass dependence of the pion
mass, and the other consists in extracting the chiral condensate from the
behaviour of the mode number of the Wilson-Dirac operator for small
eigenvalues. We find consistency between the results of the two methods, giving
a joint estimate of MeV
(, GeV, taking the square root of the string
tension MeV to set the scale), in remarkable agreement with
the 2-flavor FLAG result.Comment: 25 pages, 11 figures. v2: minor changes, matches accepted version on
JHE
Report on research activities carried out for determination of Mercury in different tissues of cetaceans
Mercury concentration in different tissues of two dolphin species (Stenella coreuleoalba and Tursiops truncatus), stranded along the Italian coasts during the period 2000â 2009, were reported in order to assess Hg distribution patterns in different tissues. The highest concentrations of Hg were found in liver samples of both species (8.4-1752 mg/kg dw for Stenella coeruleoalba and 9.6-1404 mg/kg dw for Tursiops truncatus). Relative high mercury concentrations were reported also in kidney and lung tissues. The existence of Hg bioaccumulation process over time was also reported. The dataset documents the existence of different mechanisms of mercury bioaccumulation in the different tissues analyzed
Report on research activities carried out for determination of Cadmium and Arsenic in tissues of different cetacean species
Concentrations of Cd and As were determined in organs and tissues (muscle, heart, kidney, lung and liver) of two cetacean species (Stenella coeruleoalba and Truncatus truncatus) stranded along the Italian coasts during the period 2000â2009. Significant differences were found between Cd concentrations in the different analyzed tissues. Particularly, the kidney shows the highest concentrations of Cd in all analyzed specimens, followed by the liver. The heart shows the highest As concentrations with respect to the other tissues analyzed. Specimens of S. coeruleoalba show higher Cd concentrations in their tissue than specimens of T. truncatus, probably because of a higher proportion of squid in their diet
Relazione tecnica sulle attivitĂ della Campagna oceanografica âAncheva 2016â
La presente relazione riporta le attivitĂ di ricerca della Campagna oceangrafica âAncheva 2016â, svolte a bordo della N/O âG. Dallaportaâ (nel periodo tra il 4 ed il 26 Luglio 2016) nello Stretto di Sicilia e nel mar Ionio occidentale (GSA 16 e 19) e nelle acque maltesi (GSA 15).
Nello specifico, le attivitĂ svolte vengono sono di seguito descritte sinteticamente:
- Rilevazioni acustiche degli stock di piccoli pelagici con echosounder scientifico Simrad EK60, con trasduttori split beam a scafo;
- Campionamenti biologici (di piccoli pelagici) con rete pelagica (volante monobarca), dotata di sistema acustico Simrad ITI per il controllo della geometria della rete (apertura e posizione della rete nella colonna dâacqua);
- Campionamenti di tessuti di pesci pelagici (gonadi, fegato e sangue);
- Campionamento acqua, in specifiche stazioni, con sonda multiparametrica SEABIRD mod. 9/11 plus (per la misurazione dei parametri fisico-chimici della colonna dâacqua) dotata di bottiglie Niskin (per lâanalisi di Nutrienti ed Isotopi di azoto e carbonio);
- Campionamento ittioplantonico, mediante con âBongo 40â, in specifiche stazioni, le cui bocche sono state fissate in alcool, per le analisi degli aminoacidi sulle larve di Engraulis encrasicolus
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