WISE Circumstellar Disks in the Young Sco-Cen Association

We present an analysis of the WISE photometric data for 829 stars in the Sco-Cen OB2 association, using the latest high-mass membership probabilities. We detect infrared excesses associated with 135 BAF-type stars, 99 of which are secure Sco-Cen members. There is a clear increase in excess fraction with membership probability, which can be fitted linearly. We infer that 41+-5% of Sco-Cen OB2 BAF stars to have excesses, while the field star excess fraction is consistent with zero. This is the first time that the probability of non-membership has been used in the calculation of excess fractions for young stars. We do not observe any significant change in excess fraction between the three subgroups. Within our sample, we have observed that B-type association members have a significantly smaller excess fraction than A and F-type association members.Comment: 5 Pages, 3 figure, 4 tables. Complete table 1 included. Accepted to MNRAS Letter

Testing the gamma-ray burst variability/peak luminosity correlation on a Swift homogeneous sample

We test the gamma-ray burst correlation between temporal variability and peak luminosity of the $\gamma$-ray profile on a homogeneous sample of 36 Swift/BAT GRBs with firm redshift determination. This is the first time that this correlation can be tested on a homogeneous data sample. The correlation is confirmed, as long as the 6 GRBs with low luminosity (<5x10^{50} erg s^{-1} in the rest-frame 100-1000 keV energy band) are ignored. We confirm that the considerable scatter of the correlation already known is not due to the combination of data from different instruments with different energy bands, but it is intrinsic to the correlation itself. Thanks to the unprecedented sensitivity of Swift/BAT, the variability/peak luminosity correlation is tested on low-luminosity GRBs. Our results show that these GRBs are definite outliers.Comment: Accepted for Publication in MNRAS. 10 pages, 5 figures, 3 table

Are Swift gamma-ray bursts consistent with the Ghirlanda relation?

A few tight correlations linking several properties of gamma-ray bursts (GRBs), namely the spectral peak energy, the total radiated energy, and the afterglow break time, have been discovered with pre-Swift GRBs. They were used to constrain the cosmological parameters, together with type-Ia supernovae. However, the tightness of these correlations is a challenge to GRB models. We explore the effect of adding Swift bursts to the Ghirlanda and Liang-Zhang relations. Although they are both still valid, they become somewhat weakened mostly due to the presence of significant outliers, which otherwise are apparently normal GRBs so difficult to distinguish. The increased dispersion of the relations makes them less reliable for purposes of precision cosmology.Comment: Paper accepted for publication on A&A (7 pages, 2 figures). Small changes after comment

Remanence effects in the electrical resistivity of spin glasses

We have measured the low temperature electrical resistivity of Ag : Mn mesoscopic spin glasses prepared by ion implantation with a concentration of 700 ppm. As expected, we observe a clear maximum in the resistivity (T ) at a temperature in good agreement with theoretical predictions. Moreover, we observe remanence effects at very weak magnetic fields for the resistivity below the freezing temperature Tsg: upon Field Cooling (fc), we observe clear deviations of (T ) as compared with the Zero Field Cooling (zfc); such deviations appear even for very small magnetic fields, typically in the Gauss range. This onset of remanence for very weak magnetic fields is reminiscent of the typical signature on magnetic susceptibility measurements of the spin glass transition for this generic glassy system

Modelling three-dimensional cancer-associated cachexia and therapy: the molecular basis and therapeutic potential of interleukin-6 transignalling blockade

Background: Causes and mechanisms underlying cancer cachexia are not fully understood, and currently, no therapeutic approaches are available to completely reverse the cachectic phenotype. Interleukin-6 (IL-6) has been extensively described as a key factor in skeletal muscle physiopathology, exerting opposite roles through different signalling pathways. Methods: We employed a three-dimensional ex vivo muscle engineered tissue (X-MET) to model cancer-associated cachexia and to study the effectiveness of selective inhibition of IL-6 transignalling in counteracting the cachectic phenotype. Conditioned medium (CM) derived from C26 adenocarcinoma cells was used as a source of soluble factors contributing to the establishment of cancer cachexia in the X-MET model. A dose of 1.2&nbsp;ng/mL of glycoprotein-130 fused chimaera (gp130Fc) was added to cachectic culture medium to neutralize IL-6 transignalling. Results: C26-conditioned medium induced a cachectic-like phenotype in the X-MET, leading to a decline of muscle mass (−60%; P&nbsp;&lt;&nbsp;0.001), a reduction in myosin expression (−92.4%; P&nbsp;&lt;&nbsp;0.005) and a reduction of the contraction frequency spectrum (−94%). C26-conditioned medium contains elevated amounts of IL-6 (8.61&nbsp;±&nbsp;4.09&nbsp;pg/mL) and IL6R (56.85&nbsp;±&nbsp;10.96&nbsp;pg/mL). These released factors activated the signal transducer and activator of transcription 3 (STAT3) signalling in the C26_CM X-MET system (phosphorylated STAT3/TOTAL +54.6%; P&nbsp;&lt;&nbsp;0.005), which in turn promote an enhancement of Il-6 (+69.2%; P&nbsp;&lt;&nbsp;0.05) and Il6r (+43%; P&nbsp;&lt;&nbsp;0.05) gene expression, suggesting the induction of a feed-forward loop. The selective neutralization of IL-6 transignalling, by gp130Fc, in C26_CM X-MET prevented the hyperactivation of STAT3 (−55.8%; P&nbsp;&lt;&nbsp;0.005), countered the reduction of cross-sectional area (+28.2%; P&nbsp;&lt;&nbsp;0.05) and reduced the expression of proteolytic factors including muscle ring finger-1 (−88%; P&nbsp;&lt;&nbsp;0.005) and ATROGIN1 (−92%; P&nbsp;&lt;&nbsp;0.05), thus preserving the robustness and increasing the contractile force (+20%) of the three-dimensional muscle system. Interestingly, the selective inhibition of IL-6 transignalling modulated gene regulatory networks involved in myogenesis and apoptosis, normalizing the expression of pro-apoptotic miRNAs, including miR-31 (−53.2%; P&nbsp;&lt;&nbsp;0.05) and miR-34c (−65%; P&nbsp;&lt;&nbsp;0.005), and resulting in the reduction of apoptotic pathways highlighted by the sensible reduction of cleaved caspase 3 (−92.5%; P&nbsp;&lt;&nbsp;0.005) in gp130Fc-treated C26_CM X-MET. Conclusions: IL-6 transignalling appeared as a promising target to counter cancer cachexia-related alterations. The X-MET model has proven to be a reliable drug-screening tool to identify novel therapeutic approaches and to test them in preclinical studies, significantly reducing the use of animal models

Numerical Models for the Prediction of Ship Airborne Noise Emissions

The airborne noise emitted by ships represents a pollution source affecting the surrounding environment and third parties. Nowadays, in addition to numerous other kinds of environmental impacts due to shipping activities, ship airborne radiated noise in the latest years has captured the attention of universities, industries, and Regulatory Bodies. Even though this problem can be quite annoying and has raised serious complaints from the citizens of areas close to ports, shipping routes along the coast, or inland waters, the acoustic impact of ships to date has not been subjected to systematic control. The problem is primarily driven by the presence of powerful sound sources on ships and the fact that inhabited areas are often in close proximity to areas where ships operate. In response to the need to regulate the noise emitted by ships, Lloyd's Register introduced a class notation in 2019 specifically for airborne noise emissions from ships. This notation also includes a procedure for granting the notation. Within this context, the development of mathematical models to predict the propagation of noise in the air can serve as a valuable tool for anticipating and controlling the impact of ship-related airborne noise. This paper, reports problems and methods on the practical implementation of the required classification checks, in particular as regards the simulation and validation problems. As an application example, a small part of the results obtained during an industrial research activity aimed at assessing the noise radiated into the air by a passenger ship is reported

Nonlocal field correlations and dynamical Casimir-Polder forces between one excited- and two ground-state atoms

The problem of nonlocality in the dynamical three-body Casimir-Polder interaction between an initially excited and two ground-state atoms is considered. It is shown that the nonlocal spatial correlations of the field emitted by the excited atom during the initial part of its spontaneous decay may become manifest in the three-body interaction. The observability of this new phenomenon is discussed.Comment: 17 pages, 1 figure, sub. to Phys. Rev.

TESTING the BINARY TRIGGER HYPOTHESIS in FUors

We present observations of three FU Orionis objects (hereafter, FUors) with nonredundant aperture-mask interferometry at 1.59 μm and 2.12 μm that probe for binary companions on the scale of the protoplanetary disk that feeds their accretion outbursts. We do not identify any companions to V1515 Cyg or HBC 722, but we do resolve a close binary companion to V1057 Cyg that is at the diffraction limit ($\rho =58.3\pm 1.4$ mas or 30 ± 5 au) and currently much fainter than the outbursting star (${\rm{\Delta }}K^{\prime} =3.34\pm 0.10$ mag). Given the flux excess of the outbursting star, we estimate that the mass of the companion ($M\sim 0.25{M}_{\odot }$) is similar to or slightly below that of the FUor itself, and therefore it resembles a typical T Tauri binary system. Our observations only achieve contrast limits of ${\rm{\Delta }}K^{\prime} \sim 4$ mag, and hence we are only sensitive to companions that were near or above the pre-outburst luminosity of the FUors. It remains plausible that FUor outbursts could be tied to the presence of a close binary companion. However, we argue from the system geometry and mass reservoir considerations that these outbursts are not directly tied to the orbital period (i.e., occurring at periastron passage), but instead must only occur infrequently

A New Frequency-Luminosity Relation for Long GRBs?

We have studied power density spectra (PDS) of 206 long Gamma-Ray Bursts (GRBs). We fitted the PDS with a simple power-law and extracted the exponent of the power-law (alpha) and the noise-crossing threshold frequency (f_th). We find that the distribution of the extracted alpha peaks around -1.4 and that of f_th around 1 Hz. In addition, based on a sub-set of 58 bursts with known redshifts, we show that the redshift-corrected threshold frequency is positively correlated with the isotropic peak luminosity. The correlation coefficient is 0.57 +/- 0.03.Comment: 9 pages, 17 figures, 1 table; Accepted for publication in MNRA