Valongo Observatory

This article presents a gravity data integration and a regional geophysical overview of the geological framework in the State of Paraná, southern Brazil. For data processing, we used open-source computational tools based on Python libraries from the Fatiando a Terra Project. Data processing included determining theoretical gravity on the physical surface of the Earth, calculating the Gravity Disturbance, modeling topographic masses to obtain the complete Bouguer Disturbance, data gridding using the equivalent source method, and the application of enhancement techniques. The products obtained were compared with previous geological studies, revealing a robust correlation between our results and the main geological characteristics from literature. Some relatively high values of the Bouguer Disturbance indicate important structural features, such as the Paranapanema Block and the Ponta Grossa Arch. Additionally, enhancement techniques highlighted relevant geological structures, in both the Paraná Basin and the Proterozoic orogenic basement. Using the gravity method and open-source tools, this work aims to serve as a reference for future geophysical and geological investigations in the State of Paraná. The gravity maps of the Paraná are a valuable unified database for the scientific community and for future geophysical investigations. These data will be made available in an open repository, facilitating access and encouraging use in subsequent research and practical applications.

Abstract Ensuring the long-term quality of seismic data from large networks remains a critical challenge in seismology, especially as the volume of available waveforms continues to grow. Sensor misorientation, timing instability, and relative sensitivity anomalies can introduce significant biases in quantitative analyses. To address this need, we present Scalable Seismological Pipeline for Assessment, Review, and Quality (SSPARQ), an open-source Python-based tool designed to automate the assessment of station performance based on P-wave characteristics. SSPARQ minimizes P-wave energy on the transverse component to estimate azimuthal misorientation and incorporates additional diagnostics to evaluate clock stability and intercomponent relative sensitivity consistency. The methodology requires only short waveform windows around the P-wave arrival and relies on basic criteria including signal-to-noise ratio, intercomponent energy ratios, and cross-correlation between radial and vertical components. A density-based clustering algorithm, DBSCAN, is employed to resolve time-dependent orientation trends. SSPARQ is scalable, supports parallel processing, and is well suited for retrospective evaluation of stations over multiyear deployments. We demonstrate the effectiveness of SSPARQ using three representative seismic stations: MVCO (United States National Seismic Network–USNSN), WCI (Global Seismograph Network–GSN), and KOWA (GSN). At MVCO, we detect a +20° sensor misorientation consistent with prior studies and metadata, which was corrected during maintenance in 2019. At WCI, we identify a ∼9-month period of instrumental anomalies in 2014–2015. At KOWA, although orientation remains stable, we observe progressive clock degradation beginning in late 2012, followed by a separate interval of anomalous sensitivity behavior. These case studies confirm SSPARQ’s capability to recover subtle instrumental issues using waveform-only data, without requiring metadata or synthetic modeling. SSPARQ is intended for seismologists seeking a lightweight yet robust solution for seismic data quality assessment, especially in contexts involving temporary networks, heterogeneous instrumentation, or archived data from multiple data centers.

ABSTRACT Modern surveys such as Euclid report a decline in the fraction of barred galaxies from the local Universe to $z \sim 1$, whereas the TNG50 simulation predicts higher bar fractions, in tension with observations. This discrepancy may be due to observational biases in bar detectability when comparing simulations with observations. We present a proof-of-concept study quantifying how Euclid-like observational conditions affect bar detectability in TNG50. We analysed the entire galaxy sample at $z=0.5$ and highlight one borderline case with a bar length of 2.1 kpc and strength $A_2=0.4$. Synthetic images were produced with Monte Carlo radiative transfer and realistic post-processing, and analysed with ellipse fitting and Fourier decomposition, as well as the recently constructed Zoobot analysis. Results were compared to idealized noise-free stellar mass maps. In the illustrative case the bar is clearly detected in the mass map and remains visible in the Euclid VIS $I_{\rm E}$ filter, where Zoobot also classifies it as barred, but becomes undetectable in $Y_{\rm E}$ and in the VIS–NISP RGB composite, with all methods failing outside VIS. Extending to the full $z=0.5$ sample, Zoobot recovers only 31/141 galaxies, while $A_2$ and ellipse fitting perform better (80/141 and 67/141) but still miss many short or weak bars. When non-detections are counted as unbarred, the bar fraction of 44 per cent falls to 12–33 per cent depending on method. These results demonstrate the strong impact of observational effects on bar detectability and motivate bar-fraction estimates that incorporate realistic instrumental conditions across redshift in cosmological simulations.

The Aptian-Albian interval was marked by paleoclimatic changes encompassing volcanic events and monsoonal activity of which the precise timing were not well-defined. This study presents a ~ 20 Myr cyclostratigraphic framework and provides an extended astronomical timescale using magnetic susceptibility and anhysteretic remanent magnetization datasets from the Poggio le Guaine core (Umbria-Marche Basin, Italy). Using astronomical tuning, we infer new age constraints and timespans for: (1) the Aptian and Albian stages; (2) the magnetic polarity Chron M0r; (3) the Oceanic Anoxic Events; (4) bioevents and, (5) Cretaceous oceanic red beds. These results enhance our understanding of the interplay between paleoclimatic and biotic processes in the Early Cretaceous. This study establishes a new chronostratigraphic framework for the Aptian-Albian-the most comprehensive to date in terms of resolution, integration with other geochronological methods, and temporal coverage- offering new insights into bio-chemical-geomagnetic interactions and helping refine the Geological Time Scale.

Cosmetus Perty, 1833 is a cosmetid genus with 21 species described which can be recognized by its characteristic fused spine in area III, although this character is presumably homoplastic. In this paper we describe one new species of the genus sensu lato from the Colombian pacific region based on genital morphology and external characters. Cosmetus calima sp. nov. (type locality: Valle del Cauca, Buenaventura, Bajo Calima) can be distinguished by the combination of the following features: dorsal scutum uniformly yellow without paired depigmented spots; spine undivided, shorter than dorsal scutum and not projecting backwards; femur IV long and unarmed; smooth tarsal claws III and IV; male without hypertelic chelicerae, with five basitarsomeres I and penis with a medial basal swelling on the dorsal region of the ventral plate that touches the gland. It is similar to Cosmetus acanti and Cosmetus balboa, which also inhabit the Chocó-Darién moist forests, differing subtly from them in its coloration and spot pattern, the length and inclination of spine in area III, the shape of ventral plate of penis and the position of MS D and MS E.

On May 14, 2025, a luminous object crossed the sky over Central Brazil and was identified by the Brazilian Meteor Observation Network (BRAMON) as the second stage of the Falcon 9 rocket, NORAD number 40108, undergoing atmospheric reentry. This stage is an example of space debris — artificial material launched into space that, upon losing orbital altitude, returns uncontrollably to Earth’s atmosphere. Infrasound technology, one of the four verification technologies of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) verification regime, was used to detect and characterize the infrasound signals generated by the reentry of Falcon 9. The Brasília infrasound station (I09BR), part of the International Monitoring System (IMS) for atmospheric nuclear explosions, detected a signal consistent with the rocket’s trajectory. This study analyzes the compatibility of the recorded infrasound signal with the orbital reentry, based on the trajectory geometry, propagation time, and recorded acoustic.

The chromite deposits from the Jacurici’s Valley have been mining since the '70s. This work aimed to apply audiomagnetotelluric data analysis over (i) Southern Block, where we had previous knowledge of the chromite ore in depth through drill holes; and (ii) Northern Block, where just an overall mapping was carried out. The geology is comprised of igneous and metamorphic rocks aligned following a N-S strike. The chromitites are cm- to m- layers hosted on ultramafic rocks. Based on the signature found in terms of electrical conductivity in the subsurface of the Southern Block, we identified potential anomalies with similar behavior in the Northern Block. Through inversion, 11 principal conductors were identified in both Blocks, correlated with geological information.

Recent advances in applied geophysics have greatly enhanced our ability to accurately image and understand the Earth’s physical characteristics and geological processes [...]