Search results for "Ultra"

Focal liver lesions: clinical usefulness of contrast-enhanced ultrasound in the selection of surgical patients

2009

Purpose: to evaluate the role of contrast-enhanced ultrasound (CEUS) in the characterization of focal liver lesions (FLLs) for surgical patients selection. Materials and Methods: 135 consecutive patients (71 women, 64 men) with 165 FLLs (mean size: 3.1 cm) - 89 benign (10 simple cysts, 26 hemangiomas, 29 focal nodular hyperplasia (FNH), 2 hepatocellular adenomas, 11 focal fatty sparing, 3 focal fatty areas, 5 regenerative nodules, 2 hydatid cysts, 1 abscess) and 76 malignant - 47 metastases, 26 hepatocellular carcinomas and 3 peripheral cholangiocarcinomas - underwent CEUS after the administration of SonoVue®. Two readers reviewed in consensus baseline US and CEUS scans obtained 25-30 s (ar…

Role of contrast-enhanced ultrasound in the assessment of hemangiomas of the spleen

2007

Role of contrast-enhanced ultrasound in the characterization of incidentally discovered focal liver lesions

2007

Role of contrast-enhanced ultrasound in the characterization of incidentally discovered focal liver lesions

2009

Role of contrast-enhanced ultrasound in the characterization of incidentally discovered focal liver lesions

2007

Role of contrast-enhanced ultrasound in the assessment of spleen hemangiomas

2007

Thermoelectric Radiation Detector Based on Superconductor-Ferromagnet Systems

2017

We suggest an ultrasensitive detector of electromagnetic fields exploiting the giant thermoelectric effect recently found in superconductor-ferromagnet hybrid structures. Compared with other types of superconducting detectors where the detected signal is based on variations of the detector impedance, the thermoelectric detector has the advantage of requiring no external driving fields. This is especially relevant in multipixel detectors, where the number of bias lines and the heating induced by them are an issue. We propose different material combinations to implement the detector and provide a detailed analysis of its sensitivity and speed. In particular, we perform a proper noise analysis…

Measurement of the cosmic-ray energy spectrum above 2.5×1018  eV using the Pierre Auger Observatory

2020

We report a measurement of the energy spectrum of cosmic rays for energies above 2.5×10^18 eV based on 215,030 events recorded with zenith angles below 60°. A key feature of the work is that the estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5×10^19 eV. The principal conclusions are(1) The flattening of the spectrum near 5×10^18 eV, the so-called "ankle,"is confirmed.(2) The steepening of the spectrum at around 5×10^19…

Probing the origin of ultra-high-energy cosmic rays with neutrinos in the EeV energy range using the Pierre Auger Observatory

2019

Neutrinos with energies above 1017 eV are detectable with the Surface Detector Array of the Pierre Auger Observatory. The identification is efficiently performed for neutrinos of all flavors interacting in the atmosphere at large zenith angles, as well as for Earth-skimming τ neutrinos with nearly tangential trajectories relative to the Earth. No neutrino candidates were found in ∼ 14.7 years of data taken up to 31 August 2018. This leads to restrictive upper bounds on their flux. The 90% C.L. single-flavor limit to the diffuse flux of ultra-high-energy neutrinos with an Eν -2 spectrum in the energy range 1.0 × 1017 eV -2.5 × 1019 eV is E2 dNν/dEν < 4.4 × 10-9 GeV cm-2 s-1 sr-1, placing str…

Limits on point-like sources of ultra-high-energy neutrinos with the Pierre Auger Observatory

2019

With the Surface Detector array (SD) of the Pierre Auger Observatory we can detect neutrinos with energy between 1017 eV and 1020 eV from point-like sources across the sky, from close to the Southern Celestial Pole up to 60 in declination, with peak sensitivities at declinations around ∼-53 and ∼+55, and an unmatched sensitivity for arrival directions in the Northern hemisphere. A search has been performed for highly-inclined air showers induced by neutrinos of all flavours with no candidate events found in data taken between 1 Jan 2004 and 31 Aug 2018. Upper limits on the neutrino flux from point-like steady sources have been derived as a function of source declination. An unrivaled sensit…