Searching for Jet Emission in LMXBs: A Polarimetric View

We present results taken from a study aiming at detecting the emission from relativistic particles jets in neutron star-low mass X-ray binaries using optical polarimetric observations. First, we focus on a polarimetric study performed on the persistent LMXB 4U 0614+091. Once corrected for interstellar effects, we measured an intrinsic linear polarization in the r-band of ~3% at a 3σ confidence level. This is in-line with the observation of an infrared excess in the spectral energy distribution (SED) of the source, reported in a previous work, which the authors linked to the optically thin synchrotron emission of a jet. We then present a study performed on the transitional millisecond pulsar PSR J1023+0038 during quiescence. We measured a linear polarization of 1.09 ± 0.27% and 0.90 ± 0.17% in the V and R bands, respectively. The phase-resolved polarimetric curve of the source in the R-band reveals a hint of a sinusoidal modulation at the source orbital period. The NIR -optical SED of the system did not suggest the presence of a jet. We conclude that the optical linear polarization observed for PSR J1023+0038 is possibly due to Thomson scattering with electrons in the disc, as also suggested by the hint of the modulation of the R-band linear polarization at the system orbital period

New optical and IR counterpart of MAXIJ1816-195

After the new Swift/XRT localization (ATel #15467) of the accreting millisecond X-ray pulsar MAXIJ1816-195 (Atel #15431), on June 25, 2022 (MJD 59755) we observed the field with the 3.6-m Telescopio Nazionale Galileo (TNG) in the optical (g,r,i,z-bands) and in the near-IR (K-band) with the DOLORES and NICS imagers, respectively

A telerehabilitation platform for cognitive, physical and behavioural rehabilitation in elderly patients affected by dementia

Dementia is one of the main causes of disability in elderly people and its treatment becomes, year after year, an increasingly compelling priority for the public health system. In the last years, home assistance and telemedicine have paved the way to decrease the treatments’ costs and to improve the patients and caregivers quality of life quality. In this framework, the aim of ABILITY project is to design, develop and validate an integrated platform of services aimed at supporting and enhancing the rehabilitation process for patients with dementia at their homes. ABILITY platform allows the clinician to assign rehabilitation plans with a strong compliance monitoring, enabled by the technological solutions integrated, and the holistic approach to rehabilitation, as the plan includes physical, cognitive and behavioral therapies/exercises. The ABILITY platform will be assessed through a set of validation activities, involving a small group of pilot patients, and a Randomized Control Trial. In conclusion, the ABILITY project generates a series of assistive services inside a modular and flexible platform, adaptable to the single patient and his/her needs, increasing the treatment efficiency and efficacy with respect to the state of the art

Differential diagnosis of neurodegenerative dementias with the explainable MRI based machine learning algorithm MUQUBIA

Biomarker-based differential diagnosis of the most common forms of dementia is becoming increasingly important. Machine learning (ML) may be able to address this challenge. The aim of this study was to develop and interpret a ML algorithm capable of differentiating Alzheimer's dementia, frontotemporal dementia, dementia with Lewy bodies and cognitively normal control subjects based on sociodemographic, clinical, and magnetic resonance imaging (MRI) variables. 506 subjects from 5 databases were included. MRI images were processed with FreeSurfer, LPA, and TRACULA to obtain brain volumes and thicknesses, white matter lesions and diffusion metrics. MRI metrics were used in conjunction with clinical and demographic data to perform differential diagnosis based on a Support Vector Machine model called MUQUBIA (Multimodal Quantification of Brain whIte matter biomArkers). Age, gender, Clinical Dementia Rating (CDR) Dementia Staging Instrument, and 19 imaging features formed the best set of discriminative features. The predictive model performed with an overall Area Under the Curve of 98%, high overall precision (88%), recall (88%), and F1 scores (88%) in the test group, and good Label Ranking Average Precision score (0.95) in a subset of neuropathologically assessed patients. The results of MUQUBIA were explained by the SHapley Additive exPlanations (SHAP) method. The MUQUBIA algorithm successfully classified various dementias with good performance using cost-effective clinical and MRI information, and with independent validation, has the potential to assist physicians in their clinical diagnosis

Chasing the break: tracing the full evolution of a black hole X-ray binary jet with multiwavelength spectral modeling

Black hole (BH) X-ray binaries (XRBs) are ideal targets to study the connection between accretion inflow and jet outflow. Here we present quasi-simultaneous, multiwavelength observations of the Galactic BH system MAXI J1820+070, throughout its 2018–2019 outburst. Our data set includes coverage from the radio through X-ray bands from 17 different instruments/telescopes, and encompasses 19 epochs over a 7 month period, resulting in one of the most well-sampled multiwavelength data sets of a BH XRB outburst to date. With our data, we compile and model the broadband spectra of this source using a phenomenological model that includes emission from the jet, a companion star, and an accretion flow. This modeling allows us to track the evolution of the spectral break in the jet spectrum, a key observable that samples the jet launching region. We find that the spectral break location changes over at least ≈3 orders of magnitude in electromagnetic frequency over this period. Using these spectral break measurements, we link the full cycle of jet behavior, including the rising, quenching, and reignition, to the changing accretion flow properties as the source evolves through its different accretion states. Our analysis shows consistent jet behavior with other sources in similar phases of their outbursts, reinforcing the idea that jet quenching and recovery may be a global feature of BH XRB systems in outburst. Our results also provide valuable evidence supporting a close connection between the geometry of the inner accretion flow and the base of the jet

Measurements of production cross sections of polarized same-sign W boson pairs in association with two jets in proton-proton collisions at s=13 TeV

The first measurements of production cross sections of polarized same-sign W±W±boson pairs in proton-proton collisions are reported. The measurements are based on a data sample collected with the CMS detector at the LHC at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 137fb−1. Events are selected by requiring exactly two same-sign leptons, electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass to enhance the contribution of same-sign W±W±scattering events. An observed (expected) 95% confidence level upper limit of 1.17 (0.88)fbis set on the production cross section for longitudinally polarized same-sign W±W±boson pairs. The electroweak production of same-sign W±W±boson pairs with at least one of the Wbosons longitudinally polarized is measured with an observed (expected) significance of 2.3 (3.1) standard deviations.SCOAP

Optical switching application of ZnSe/MgF2 photonic band gap structures based on thermal nonlinear nonlinearities

We studied a ZnSe/MgF2 multilayer in order to modulate its optical reflectance. An electrically induced temperature increase is responsible for changes in the refractive index of the layers. The reflected signal is therefore decreased

Novel SOI inertial sensors with optical readout based on transparent metals

A novel optical microsensor has been fabricated using a SOI-based technology. The basic device is a symmetric flexure in which the central plate is used both as seismic mass and as optical target for displacement measurements. The device includes a multilayer, metal-dielectric Photonic Band Gap (PBG) structure, deposited on a flat substrate and bonded topside at a fixed distance from the movable plate. The reflection intensity of a light beam, pointed to the overall optical structure (top PBG, air gap, the moving plate), will depend on the air gap thickness whose value is determined by the displacement of the proof mass induced by the measurand, the external force. In particular, the realization of highly sensitive accelerometers is addressed here, the structure presented allows for detecting accelerations of the order of a few mG that produce displacements of the plate of few nanometers. Experimental prototypes have been realized and some results are shown

Tunable absorption resonance in electromechanical one-dimensional metallodielectric photonic band gap structures

We present the results of an experimental study of an electromechanical, one-dimensional, metallodielectric photonic band gap structure. We monitor the reflectance as a function of the thickness of an air gap located inside the stack. The results suggest that, by changing the thickness of the air gap by approximately 20 nm, a large contrast can be achieved between high- and low-reflectance states, as reflectance switches from a fraction of a percent to about 70%. Using this approach, we are able to selectively remove a relatively narrow but tunable wavelength range from the reflected spectrum, thus making possible applications to accelerometers, linear optical switches, modulators, and other specialized filters in the visible range. The characteristic absorption spectrum can be controlled by varying air gap and dielectric layer thicknesses

Optical limiting effects in hybrid electromechanical-metallo-dielectric Ag/ZnO photonic band gap structures

We study a combination of nonlinear interactions and electromechanical switching in one-dimensional metallo-dielectric photonic band gap (PBG) structures. The structure, which is composed of two similar stacks consisting of ZnO and Ag alternating layers separated by an air layer of tunable thickness, is arranged to take advantage of both active and passive transmission control mechanisms. Active transmission control is provided by the activation of electromechanical switches, and acts on a time scale of microseconds. Passive transmission control is based on the onset on nonlinear two-photon absorption in the ZnO layers for high incident intensities, and occurs on a time scale of picoseconds. Preliminary samples were prepared to show that the two degrees of freedom can be implemented in a metallo-dielectric structure. The reduction of transmittance with increasing incident intensity was demonstrated in Ag/ZnO samples realized by means of dual ion beam sputtering technique. Electromechanical transmission control was instead demonstrated in a metallo-dielectric structure composed of thermally evaporated Ag/MgF2 multilayer stack which contained an air gap. We therefore show that the combination of the nonlinear behavior exhibited by ZnO and modulation of an air gap results in a more responsive, faster device, with stronger attenuation and higher contrasts in the transmission of light between "on" and "off states. We conclude that this kind of structure has great potential for broadband optical limiting and switching applications