Space (Italy)

Abstract We introduce a new photometric catalog of RR Lyrae (RRL) variables (∼300,000) mainly based on data available in public datasets. We also present the largest and most homogeneous spectroscopic dataset of RRLs and blue horizontal branch (BHB) stars ever collected. This includes radial velocity measurements (∼16,000) and iron abundances (Δ S method for 8140 RRLs, plus 547 from literature). Elemental abundances based on high-resolution spectra are provided for 487 RRLs and 64 BHB stars. We identified candidate RRLs associated with the main Galactic components and their iron distribution function (IDF) becomes more metal rich when moving from the halo ([Fe/H] = −1.56) to the thick disk (TCD; [Fe/H] = −1.47) and thin disk (TND; [Fe/H] = −0.73). Furthermore, halo RRLs and RRLs in retrograde orbits are α enhanced ([ α /Fe]=0.27, σ = 0.18), while TCD RRLs are either α enhanced ([Fe/H] ≤ −1.0) or α poor ([Fe/H] > −1.0), and TND RRLs are mainly α poor ([ α /Fe] = −0.01, σ = 0.20). We also identified RRLs associated with the main stellar streams—Gaia–Sausage–Enceladus (GSE); Sequoia, Helmi, and Sagittarius—and we found that their IDFs are quite similar to halo RRLs. However, GSE RRLs lack the metal-poor/metal-rich tails and their α -element distribution is quite compact. The iron radial gradient in Galactocentric distance for TND, TCD, and halo RRLs is negative and it decreases from −0.026, to −0.010, and to −0.002 dex kpc −1 . The iron radial gradient based on dry halo (halo without substructures) RRLs is, within the errors, equal to the global halo. We also found a strong similarity between iron and [ α /Fe] radial gradients of Milky Way RRLs and M31 globular clusters throughout the full range of galactocentric distances covered by the two samples.

Quasars at the dawn of cosmic time ( z > 6) are fundamental probes for investigating the early coevolution of supermassive black holes and their host galaxy. Nevertheless, their infrared spectral energy distribution currently remains poorly constrained because the photometric coverage that probes the far-infrared wavelength range in which the dust modified blackbody is expected to peak (∼80 μm) is limited. We studied the high-frequency dust emission via a dedicated ALMA Band 8 (∼400 GHz) campaign targeting 11 quasar host galaxies at 6 < z < 7. Combined with archival observations in other ALMA bands, this program enables a detailed characterization of their infrared emission, which allowed us to derive dust masses ( M d ), dust emissivity indexes ( β ), dust temperatures ( T d ), infrared luminosities ( L IR ), and associated star formation rates (SFRs). Our analysis confirmed that dust temperature is higher in this sample (34−65 K) than in local main-sequence galaxies, and this finding can be linked to the increased star formation efficiency we derived, as also suggested by the [CII] 158 μm deficit. Most remarkably, we note that the average value of T d of this sample does not differ from the one that is observed in luminous, ultraluminous and hyperluminous infrared galaxies at different redshifts that show no signs of hosting a quasar. Finally, our findings suggest that the presence of a bright AGN does not significantly bias the derived infrared properties, although further high frequency observations with a high spatial resolution might reveal more subtle effects on subkiloparsec scales.

Abstract In this article, we present the study for the reclassification of the variability of the star CzeV961 by SSV-UAI-GRAV, classified by Variable Star Index as an EW eclipsing binary. In the same field of observation, there were two variable stars already discovered by Gaia but of an undefined type. In examining the comparison stars for our study, we then discovered a new variable star that had not yet been classified. The star CzeV961 turned out to be a Gamma Doradus variable star, like the two Gaia stars, while the newly discovered variable turned out to be an RS Canum Venaticorum type star.

Ionospheric scintillations, driven by irregularities in electron density, significantly disrupt Global Navigation Satellite Systems (GNSS), compromising signal integrity and positioning accuracy. Brazil, due to its geographical position near both the Equatorial Ionospheric Anomaly and the South Atlantic Magnetic Anomaly, is among the regions most affected by such disturbances - particularly during the solar maximum of the current cycle. Precision agriculture (PA), which relies heavily on GNSS technologies for tasks such as automated guidance and resource optimization, is therefore increasingly exposed to the risk of signal degradation. Despite the growing technological dependence, little is known about the actual economic impact of these phenomena on the sector. This paper adopts a mixed-method approach to estimate the financial losses induced by ionospheric scintillations on PA in Brazil. The methodology integrates qualitative data collected through surveys of GNSS-dependent farms with quantitative data representative of the farm scenarios, incorporating metrics such as downtime, planting delays, yield penalties, and market values. Results will provide novel insights into the vulnerability of PA to space weather events in equatorial regions and support the development of risk mitigation strategies and informed policy decisions for safeguarding agricultural productivity.

This paper presents the design, simulation, and experimental validation of a dual-Circularly Polarized (CP) array antenna to be used as single element for a bistatic radar system, aimed at detecting and tracking objects in Low Earth Orbit (LEO). The antenna operates at 412 MHz in reception mode and consists of an array of 19 slotted-patch radiating elements with a cavity-based metallic superstrate, designed to support dual circular polarization. These elements are arranged in a hexagonal configuration, enabling the array structure to achieve a maximum realized gain of 17 dBi and a Side Lobe Level (SLL) below −17 dB while maintaining high polarization purity. Two identical analog feeding networks enable the precise control of phase and amplitude, allowing the independent reception of Right-Hand and Left-Hand Circularly Polarized (RHCP and LHCP) signals. Full-wave simulations and experimental measurements confirm the high performance and robustness of the system, demonstrating its suitability for integration into large-scale Space Situational Awareness (SSA) sensor networks.

In wireless sensor networks for reusable launchers, the electromagnetic characterization and electromagnetic compatibility analyses are relevant due to the reference operational scenario, which implies a complex, and sometimes dynamic, electromagnetic environment. This work proposes a methodological framework for the design of the network and for the analysis of the related electromagnetic environment within the stages of a given launcher. Based on the preliminary positioning of the network nodes, the framework prescribes a workflow and the related toolset for determining the optimal network topology focusing on the weights, the operation of the transceivers, and the overall radiated power. The optimal network configuration is simulated by using computational electromagnetics strategies in order to assess the electromagnetic environment induced by the sensor network itself. The paper provides some results concerning a case study for a specific launcher.

Previous studies showed that properties of higher-threshold motor units (MUs) and neuromuscular junction (NMJ) function are preserved during short-term disuse. This study aimed to test how a longer disuse period affects MU properties, NMJ transmission, and NMJ morphology remodeling. Nine young healthy males (age: 18-29 years) underwent 21 days of horizontal bed rest. Pre- (BR0) and post-bed rest (BR21), quadriceps maximal voluntary contraction (MVC), and size were assessed. We combined intramuscular electromyography (iEMG) and high-density surface electromyography (HDsEMG) recordings on the vastus lateralis to assess MU properties at 25% and 50% of MVC. Muscle biopsies and blood samples were also collected. Quadriceps MVC and size decreased at BR21. We found alterations in MU properties at both contraction intensities, including reduced discharge rate, MU potential area changes, and increased complexity. NMJ transmission was found to be reduced at BR21 at 25% MVC. This functional NMJ impairment was biochemically corroborated by an increase in serum C-terminal agrin fragment concentration, a biomarker of NMJ instability. In addition, a direct assessment of NMJ morphology revealed the presence of some denervated NMJs exclusively at BR21. In conclusion, 21-day bed rest altered MU properties across different contraction intensities and impaired NMJ transmission with initial signs of remodeling/denervation. Disuse duration appears to be a critical factor, as previous shorter studies failed to detect some of these changes. We believe these findings are clinically relevant for disuse after trauma, surgery, or illness, and may support the development of effective countermeasures.

Radio frequency identification (RFID) technology has gained significant attention in various industry sectors due to its potential for efficient inventory management, asset tracking, and object localization. Different RFID technologies are available; resorting to harmonic signals is currently less used but, recently, has gained interest in research activity. In this study, we present the design, prototype realization, and performance evaluation of a dual-band dual-polarized harmonic tag. The tag incorporates a dual-band matching circuit utilizing a zero-bias Schottky diode HSMS-2850 connected to a perturbed annular ring patch antenna. The antenna, in fact, is able to radiate in cross-polarization at the higher frequency. Through a comprehensive design methodology, including simulation optimization and prototype fabrication, we demonstrate the successful implementation of the tag. Measurements to validate the impedance matching properties, radiation patterns, and backscattering capability of the tag are also shown.

We perform single-event effect (SEE) tests with well-characterized fully fragmented (i.e., beyond Bragg peak) high-energy heavy-ion beams and compare the results with those expected from conventional, mono-linear energy transfer (mono-LET) measurements, showing a satisfactory level of agreement between the two. This compliance paves the way for the exploitation of simulation tools for accurately quantifying the ion fragmentation impact on SEE rates for both ground-level testing conditions and space galactic cosmic-ray (GCR) environments, with electronics operating behind significant thicknesses of shielding. The satisfactory agreement level is also encouraging in view of the possible usage of fragmented heavy-ion beams for ground-level SEE testing of electronics.