Roma Tre University

About: Roma Tre University is a education organization based out in Rome, Lazio, Italy. It is known for research contribution in the topics: Large Hadron Collider & Galaxy. The organization has 4434 authors who have published 15352 publications receiving 374888 citations. The organization is also known as: Universita degli Studi Roma Tre & RomaTre.

Phase behavior and critical activated dynamics of limited-valence DNA nanostars

Abstract: Colloidal particles with directional interactions are key in the realization of new colloidal materials with possibly unconventional phase behaviors. Here we exploit DNA self-assembly to produce bulk quantities of “DNA stars” with three or four sticky terminals, mimicking molecules with controlled limited valence. Solutions of such molecules exhibit a consolution curve with an upper critical point, whose temperature and concentration decrease with the valence. Upon approaching the critical point from high temperature, the intensity of the scattered light diverges with a power law, whereas the intensity time autocorrelation functions show a surprising two-step relaxation, somehow reminiscent of glassy materials. The slow relaxation time exhibits an Arrhenius behavior with no signs of criticality, demonstrating a unique scenario where the critical slowing down of the concentration fluctuations is subordinate to the large lifetime of the DNA bonds, with relevant analogies to critical dynamics in polymer solutions. The combination of equilibrium and dynamic behavior of DNA nanostars demonstrates the potential of DNA molecules in diversifying the pathways toward collective properties and self-assembled materials, beyond the range of phenomena accessible with ordinary molecular fluids.

Probing the Evolution of Infrared Properties of z ∼ 6 Quasars: Spitzer Observations

Abstract: We present Spitzer observations of 13 z ~ 6 quasars using the Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS). All the quasars except SDSS J000552.34-000655.8 (SDSS J0005-0006) were detected with high signal-to-noise ratio in the four IRAC channels and the MIPS 24 μm band, while SDSS J0005-0006 was marginally detected in the IRAC 8.0 μm band and not detected in the MIPS 24 μm band. We find that most of these quasars have prominent emission from hot dust, as evidenced by the observed 24 μm fluxes. Their spectral energy distributions (SEDs) are similar to those of low-redshift quasars at rest frame 0.15-3.5 μm, suggesting that accretion disks and hot-dust structures for these sources have already reached maturity. However, SDSS J0005-0006 has an unusual SED that lies significantly below low-redshift SED templates at rest frame 1 and 3.5 μm and thus shows a strong near-IR (NIR) deficit and no hot-dust emission. Type I quasars with extremely small NIR-to-optical flux ratios such as SDSS J0005-0006 are not found in low-redshift quasar samples, indicating that SDSS J0005-0006 has different dust properties at high redshift. We combine the Spitzer observations with X-ray, UV/optical, millimeter/submillimeter, and radio observations to determine bolometric luminosities for all the quasars. We find that the four quasars with central black hole mass measurements have Eddington ratios of order unity.

Magmas near the critical degassing pressure drive volcanic unrest towards a critical state

Abstract: During the reawaking of a volcano, magmas migrating through the shallow crust have to pass through hydrothermal fluids and rocks. The resulting magma-hydrothermal interactions are still poorly understood, which impairs the ability to interpret volcano monitoring signals and perform hazard assessments. Here we use the results of physical and volatile saturation models to demonstrate that magmatic volatiles released by decompressing magmas at a critical degassing pressure (CDP) can drive volcanic unrest towards a critical state. We show that, at the CDP, the abrupt and voluminous release of H2O-rich magmatic gases can heat hydrothermal fluids and rocks, triggering an accelerating deformation that can ultimately culminate in rock failure and eruption. We propose that magma could be approaching the CDP at Campi Flegrei, a volcano in the metropolitan area of Naples, one of the most densely inhabited areas in the world, and where accelerating deformation and heating are currently being observed.

Search for resonances in diphoton events at √s=13 TeV with the ATLAS detector

Abstract: Searches for new resonances decaying into two photons in the ATLAS experiment at the CERN Large Hadron Collider are described. The analysis is based on protonproton collision data corresponding to ...