Christian Schuler, Boris J. P. Kaus, Eline Le Breton
et al.
Abstract The motion of the Adriatic microplate is thought to be highly sensitive to the surrounding subduction zones and the convergence of Africa and Eurasia. However, our understanding of the mantle dynamics in the Mediterranean region and its effect on plate motion remains incomplete. Here, we present a large set of 3D thermomechanical models of the entire Mediterranean region over the last 35 Myr to understand what controls the motion of the Adriatic microplate. The simulations take the convergence of the African and Arabian plates with the Eurasian plate into account, along with the dynamics of the subduction systems in the western (Apennines‐Calabria), central (Dinarides‐Hellenides) Mediterranean and in the Alpine‐Carpathian region. Our results demonstrate that the subduction systems around Adria are highly coupled, which gives rise to complex asthenospheric flow in the central Mediterranean. We find that the plate motion of the Adriatic microplate over the last 35 Myr is controlled by the interplay of three main factors: (a) the convergence between the African and Eurasian plates, (b) the retreat of the Alpine subduction zone to the north of Adria, and (c) the distance between the Calabrian and Hellenic subduction zones around Adria. Furthermore, in a system characterized by active convergence between Africa and Eurasia, the slab pull exerted by nearby subduction zones can only notably influence the motion of the Adriatic microplate if these subduction zones are located within a few hundred kilometers of Adria.
Stereo matching algorithms are considered one of the most important subtasks in 3-D reconstruction, as 3-D coordinates are derived from the disparity values of pixels obtained through stereo matching. Recently, deep learning-based satellite stereo matching algorithms have been widely investigated, as they can capture both deep and shallow features of complex satellite scenes. However, several problems in satellite stereo matching, due to the unique properties of satellite images, remain unsolved, particularly in textureless and repetitive regions. In these regions, a single object in a satellite image is likely to be matched with similar objects, causing multiple disparity probabilities and shifts in the disparity estimation. To address the problem of disparity shifts, we propose a novel cost volume refinement strategy (CVRS). CVRS introduces both left-right and left-left cost volumes, which work together to refine disparities and eliminate false matches in textureless or repetitive regions, while preserving the original disparity values. With CVRS, we propose a new model for satellite stereo matching, the self-refined cost volume network (SRCV-Net). We evaluated CVRS and SRCV-Net on the US3D and WHU-Stereo datasets, comparing it using the EPE and D1 metrics. The application of CVRS demonstrated performance improvements in all models, and SRCV-Net achieved superior accuracy in satellite stereo matching. Furthermore, CVRS can be easily applied to various models with minimal structural changes and a small increase in parameters. SRCV-Net, with its innovative CVRS, provides an effective solution to the challenges of satellite stereo matching, offering enhanced accuracy, efficiency, and adaptability.
The accurate determination of the absolute energy scale in cosmic ray measurements is both a challenging and fundamentally important task. We present how measurements of radio pulses from extensive air showers with the Auger Engineering Radio Array, combined with per-event simulations of radio emission using the CoREAS extension of CORSIKA, allow us to determine the energy scale of cosmic rays between $3\cdot 10^{17}$\,eV and several $10^{18}$\,eV. Our analysis accounts for many factors, each of which is controlled on the 5\% level or better. The absolute calibration of the antennas and the entire analog signal chain builds on a Galactic calibration in combination with a detailed understanding of the antenna-gain patterns. Additional key elements include compensation for temperature-dependent signal amplification, continuous detector health monitoring, an active veto for thunderstorm conditions, an unbiased event reconstruction, and per-event atmospheric modeling in the simulations. The analysis benefits from a high-statistics dataset of over 800 measured cosmic ray showers. We describe our analysis method, perform multiple cross-checks, and evaluate systematic uncertainties. We find that absolute energies determined with AERA are 12\% higher than those established with the Auger Fluorescence Detector, a result well in agreement within systematic uncertainties and thus a strong independent confirmation of the absolute energy scale of the Pierre Auger Observatory.
Ellis R. Owen, Leonard E. C. Romano, Kentaro Nagamine
Galaxies with high star-formation rate surface densities often host large-scale outflows that redistribute energy, momentum, and baryons between the interstellar medium and the halo, making them a key feedback channel regulating galaxy evolution. Despite their importance, the driving physics behind galactic outflows and their interaction with the surrounding halo is yet to be fully understood. In particular, the influence of a pre-existing reservoir of cosmic rays (CRs) in galaxy halos has not been clearly established. We determine the conditions required to launch outflows in the presence of halo CRs and investigate how CR pressure gradients modify outflow speeds. We find that CR halos suppress the development of large-scale, CR-driven winds and redirect CR feedback toward local recycling flows. Slow outflows are therefore more likely in young galaxies lacking extended CR halos, while fast winds in intense starbursts are dominated by momentum injection and largely unaffected by halo CRs.
Empirical observations confirm that the universe’s components are diverging at an accelerating rate. This acceleration suggests that the motion of celestial bodies over vast distances is differentiable to a higher order with respect to time. Hubble’s law captures this time-dependent expansion, derived from the exponential time-displacement relation. To describe these large-scale dynamics, while maintaining translational symmetry and energy conservation, higher-order Lagrangian equations are employed to derive equations of motion across cosmic distances. These equations, which have influenced the foundations of classical mechanics, introduce the concept of negative inertia, where mass tends to alter its dynamical state spontaneously. While Newton’s theory of gravitation effectively explains short-range cosmic interactions, its limitations become evident when applied to large-scale phenomena such as galactic rotation and cosmic expansion. Similarly, Einstein’s general relativity, originally formulated for local gravitational effects, struggles to describe the universe as a whole. These challenges lead to fundamental issues, including the instability of a static universe and the presence of negative energy in an expanding one. Although the ΛCDM model successfully explains cosmic expansion, the true nature of dark energy remains unresolved. By deriving higher-order equations of motion within a general relativistic framework, cosmic expansion can be explained in a way that accounts for dark energy as a manifestation of negative or spontaneous inertia rather than an unknown energy form. This approach provides a theoretical basis for the universe’s continuous growth, avoiding predictions of gravitational collapse and the resulting space-time incompleteness.
Manali S. Nayak, David B. Bonan, Emily R. Newsom
et al.
Abstract State‐of‐the‐art climate models simulate a large spread in the mean‐state Atlantic meridional overturning circulation (AMOC), with strengths varying between 12 and 25 Sv. Here, we introduce a framework for understanding this spread by assessing the balance between the thermal‐wind expression and surface water mass transformation in the North Atlantic. The intermodel spread in the mean‐state AMOC strength is shown to be related to the overturning scale depth: climate models with a larger scale depth tend to have a stronger AMOC. We present a physically motivated scaling relationship that links intermodel variations in the scale depth to surface buoyancy fluxes and stratification in the North Atlantic, and thus connects North Atlantic surface processes to the interior overturning circulation. Climate models with a larger scale depth tend to have stronger surface buoyancy loss and weaker stratification in the North Atlantic. These results offer a framework for reducing mean‐state AMOC biases in climate models.
The Russia–Ukraine conflict has persisted for over a year, posing challenges in assessing and verifying the extent of damage through on-site investigations. Nighttime light (NTL) remote sensing, an emerging approach for studying regional conflicts, can complement traditional methods. This article employs National Aeronautics and Space Administration's Black Marble products to reveal the response characteristics of NTL intensity at national and state scales during the first anniversary of the conflict (January 2022 to February 2023) in Ukraine. The article used the NTL ratio index to assess the relative intensity of NTL and month-on-month change rate, nighttime light change rate index (NLCRI), and the rate (<italic>R</italic> value) of linear regression analysis to depict spatiotemporal dynamics. In addition, Theil–Sen median trend analysis and Mann–Kendall tests were employed to analyze intensity trends, with a “dual-threshold method” to reduce extensive noise interference. The results showed: At the national scale, the conflict resulted in an 84.0% decrease in NTL across Ukraine. At the state scale, the most severe NTL decline occurred near the southwestern border and eastern conflict zone under Ukrainian government control, witnessing over 80% decline rates. The correlation of decreases in NLCRI and <italic>R</italic> values with population displacement, infrastructure damage, or curfew measures demonstrated that the concentration of refugees and electricity facility restoration led to increased NLCRI and <italic>R</italic> values. Overall, NTL reflects critical moments at the national scale and provides insights into military intentions and humanitarian measures at the state scale. Therefore, NTL can effectively serve as a tool for observation and assessment in military conflicts.
Motivated by results recently reported by the CMS Collaboration about an excess in the di-photon spectrum at about 96 GeV, especially when combined with another long-standing anomaly at the same value in the $b\bar b$ invariant mass spectrum in four-jet events collected at LEP, we show that a possible explanation to both phenomena can be found at 1$\sigma$ level in a generic 2-Higgs Doublet Model (2HDM) of Type-III in presence of a specific Yukawa texture, wherein Lepton Flavour Violating (LFV) (neutral) currents are induced at tree level. Bounds from Higgs data play a major role in limiting the parameter space of this scenario, yet we find solutions with $m_H = 125$ GeV and $m_h = 96$ GeV consistent with current theoretical and experimental bounds.
The KM3NeT Collaboration is incrementally building a network of water-Cherenkov neutrino observatories in the Mediterranean Sea, consisting of two telescopes, named ARCA (Astroparticle Research with Cosmics in the Abyss) and ORCA (Oscillation Research with Cosmics in the Abyss), sharing the same detection technology. ARCA, located off the shores of Sicily, in its completed shape will be a cubic-kilometre scale modular telescope made of 230 detection units, optimised for neutrino astronomy in the TeV-PeV energy range. ORCA, off the shores of Toulon (France), will be a 7-Mton modular telescope made of 115 detection units, focused on neutrino oscillations and neutrino mass ordering, for neutrinos in the 1-100 GeV energy range. At the current time, ARCA consists of 21 detection units whereas ORCA has 18 already installed. Both telescopes have been already taking data for a few years, providing good understanding of backgrounds as well as of the expected signals and hence of the scientific potential of KM3NeT. The technique for neutrino detection and measurement is reviewed, along with outlooks for the completion of the two telescopes and the expected performances for detection of astrophysical neutrino sources, measurement of neutrino oscillation parameters and neutrino mass ordering. Contributions of KM3NeT to global efforts for multimessenger astronomy are also discussed. Early physics outputs of both telescopes are reported.
Global climate change is causing various negative impacts on urban ecosystems and energy systems. To effectively mitigate and adapt to these changes, it is important to understand the contributions of background climate and local effects to urban thermal environment variation. This study utilized the empirical orthogonal function (EOF) approach to deconstruct long-term MODIS land surface temperature (LST) datasets to obtain the main features of change in daytime and nighttime thermal environments. Local bivariate spatial autocorrelation analysis was used to explore the underlying causes of these changes. The main EOF modes explained 73.14% and 81.33% of daytime and nighttime thermal environment variation, respectively. The correlation coefficient between the time coefficient of the main modes and the average LST was > 0.99, reflecting the role of global effect caused by background climate change. The secondary EOF modes explained 12.51% and 4.12% of daytime and nighttime thermal environment variation, respectively, and were spatially correlated with changes in landscape thermal intensity, reflecting local effect caused by landscape change and anthropogenic heat emissions. In expansion and renewal areas, industrial zones and compact high-rise buildings had the most obvious warming effect on the daytime thermal environment, while mid-to-high-rise buildings had the most obvious warming effect on the nighttime thermal environment. The results of this study provide valuable insights into the mechanisms of background climate and local effects on the urban thermal environment, and provide a reference for formulating effective strategies for mitigating and adapting to change in urban areas, and for promoting sustainable development.
The Mu2e experiment will search for a Standard Model violating rate of neutrinoless conversion of a muon into an electron in the presence of an aluminum nucleus. Observation of this charged lepton flavor violating process would be an unambiguous sign of new physics. Mu2e will improve upon previous searches for this process by four orders of magnitude. This requires the world's highest-intensity muon beam, a detector system capable of efficiently reconstructing the 105 MeV/c conversion electron signal, and minimizing sensitivity to background events. A pulsed 8 GeV proton beam strikes a target, producing pions that decay into muons. Beam outside the pulse must be suppressed to $<10^{-10}$ to reduce beam-related backgrounds. The muon beam is guided from the production target along the transport system and onto the aluminum stopping target. Conversion electrons leave the stopping target and propagate inside a solenoidal magnetic field to the tracker and electromagnetic calorimeter. The tracker is a system of straw tube panels filled with Ar/CO$_2$ at 1 atm that tracks particles inside of a solenoidal B-field and measures their momenta with $\sim100$ keV/$c$ resolution to resolve signal events from decay-in-orbit backgrounds. The CsI calorimeter provides $E/p$ and is used to seed the track reconstruction algorithm with $\sigma_E /E \sim{}10\%$ and $\sigma_t<500~\rm{ps}$. Additionally, a novel cosmic ray veto with greater than 99.99\% efficiency brings the expected number of background events to fewer than one over three years of running. To normalize the experiment, the stopping target monitor measures the rate of capture photons from muons incident on the stopping target by using a system of high-purity germanium and lanthanum bromide scintillators.
Multi-physical inversion plays a critical role in geophysics. It has been widely used to infer various physical properties~(such as velocity and conductivity). Among those inversion problems, some are explicitly governed by partial differential equations~(PDEs), while others are not. Without explicit governing equations, conventional multi-physical inversion techniques will not be feasible and data-driven inversion requires expensive full labels. To overcome this issue, we develop a new data-driven multi-physics inversion technique with extremely weak supervision. Our key finding is that the pseudo labels can be constructed by learning the local relationship among geophysical properties at very sparse well-logging locations. We explore a multi-physics inversion problem from two distinct measurements~(seismic and EM data) to three geophysical properties~(velocity, conductivity, and CO$_2$ saturation). Our results show that we are able to invert for properties without explicit governing equations. Moreover, the label data on three geophysical properties can be significantly reduced by 50 times~(from 100 down to only 2 locations).
In this paper we provide a comprehensive comparison of in situ electron density (Ne) and temperature (Te) measured by Langmuir probe (LAP) on board the China Seismo‐Electromagnetic Satellite (CSES), with nearly simultaneous measurements from the Swarm B satellite, incoherent scatter radar (ISR) at Millstone Hill, as well as predictions from empirical models including the incoherent scatter radar ionospheric model (ISRIM) for Millstone Hill and International Reference Ionosphere model (IRI‐2016). Results reveal that the global distributions and their relative variations of Ne/Te from CSES and Swarm are quite consistent during conjunction periods of the two satellites, although the absolute values of Swarm Ne are proportionally larger than that of CSES. The large‐scale ionospheric structures, such as the equatorial ionization anomaly (EIA), the longitudinal wave number (WN3/4), the Weddell Sea anomaly (WSA), the northern midlatitude summer nighttime anomaly (MSNA), and the midlatitude ionospheric trough (MIT), are well represented by the CSES measurements. For the temporal variation over Millstone Hill station, CSES Ne at nightside shows some different characteristics from the predictions of IRI and ISRIM, possibly due to the influences of MIT and midlatitude arc (MLA) that are often observed at latitudes of Millstone Hill. Our results suggest that the CSES in situ plasma parameters are reliable with a high scientific potential for investigation of geophysics and space physics.
Abstract The International Particle Physics Group (IPPOG) is a global network active in informal education and outreach in particle physics and related research, including cosmic-ray and astro-particle physics. Since many years, IPPOG has been actively supporting the International Cosmic Day organized by DESY and the International Muon Week organized by Quarknet. In 2015 IPPOG started work on establishing a universal portal through which successful cosmic-ray study programmes can reach out to teachers and students around the world. This common web platform is being developed by IPPOG in the frame of its new IPPOG web pages. It will contain all information for schools interested in taking part in cosmic-ray experiments and analysing real data in classroom; also instructions about how to build, borrow, or purchase cosmic-ray detectors. The platform will also facilitate collaboration and exchanges between the experiments’ project managers and advertising of related events.
En este estudio se presenta la comparación de depósitos de ambientes silicoclásticos actuales con los correspondientes al Pleistoceno-Holoceno del SE de la costa bonaerense donde se ha reconocido actividad microbiana en los sedimentos. Se comparan las diversas características sedimentológicas de las acumulaciones, entre ellas la fábrica, granulometría, composición mineralógica, presencia de microorganismos o rasgos derivados y estructuras sedimentarias. El objetivo del trabajo es comprender el paleoambiente, la ocurrencia de los mecanismos de formación que actuaron en el pasado y su relación con el marco ambiental donde se han producido mediante evidencias biosedimentarias en comparación con análogos actuales. En el ambiente actual del estuario de Bahía Blanca y el costero marginal de Paso Seco se han identificado diversas estructuras sedimentarias inducidas por actividad microbiana, generadas por los procesos hidrodinámicos propios de la planicie supramareal donde se encuentran. También se han estudiado depósitos asociados a la presencia de actividad microbiana del Pleistoceno tardío en el sector costero de la Reserva Paleoicnológica de Pehuen Có, y del Holoceno temprano-medio en los sitios arqueológicos La Olla 3 y 4 y Monte Hermoso 1. En los primeros se ha verificado la preservación de huellas de mega-mamíferos extintos y aves con notable calidad y en los segundos se ha comprobado una excelente conservación de restos óseos, vegetales y de pisadas humanas. Además de la observación directa de estructuras sedimentarias, fábrica sedimentaria y otros rasgos texturales se han llevado a cabo diferentes análisis que permitieron corroborar la existencia de actividad microbiana en los sedimentos. Entre ellos se han realizado análisis microscópicos, petrográficos y de rayos X. Las observaciones y micrografías realizadas en microscopio electrónico de barrido (MEB) han permitido la identificación de la relación de los sedimentos con microorganismos, reconociendo la presencia de SEP (sustancias poliméricas extracelulares) y de minerales autigénicos como la pirita. Los análisis de secciones delgadas bajo microscopio petrográfico, han permitido la comparación de la fábrica entre depósitos actuales y de los paleoambientes asociado a la presencia de cianobacterias. Los análisis de rayos X permitieron determinar minerales autigénicos como calcita, calcita magnesiana y dolomita. Los resultados del trabajo permiten reconocer las características distintivas de los depósitos asociados a la presencia de actividad microbiana. Entre ellas se destaca la identificación de laminación de espesor milimétrico a centimétrico, que es la característica más sobresaliente de la presencia de microorganismos, reconocida como biolaminación, tanto en visión macroscópica como en secciones delgadas. Se reconocieron estructuras sedimentarias relacionadas con el metabolismo bacteriano (que involucran procesos de crecimiento, de decaimiento, etc.), el efecto impermeabilizante del biofilm, de plasticidad y cohesividad. Se documentaron estructuras microbianas como respuesta a los procesos físicos reinantes y se reconoció la importancia de las matas microbianas en la preservación de icnitas por medio de la litificación temprana.
Unmanned aerial vehicle (UAV) images have become the main remote sensing data sources for varying applications, and structure from motion (SfM) is the golden standard for resuming camera poses. Matching local feature descriptors is the prerequisite for the accurate and complete orientation of UAV images. Recently, some newly proposed learned methods have been shown to outperform the hand-crafted methods, such as the scale invariant feature transform (SIFT) and its variants, and almost all learned methods have been trained and evaluated by using images from the internet with varying focal lengths and varying size. It is of interest to investigate the performance of these learned methods with their pretrained models for feature detection and description in the context of the SfM-based orientation. Thus, this article conducts a comprehensive evaluation of both advanced hand-crafted and newly proposed learned detectors and descriptors by using four UAV datasets. The performance of these selected methods is compared in the context of feature matching and the SfM and (multiview stereo) MVS-based reconstruction. Experimental results demonstrate that the learned descriptors combined with the SIFT-like detectors can provide accurate and complete feature correspondences and achieve better or competitive performance in the SfM and MVS-based reconstruction. For UAV image orientation, the learned descriptors can be an alternative to the existing hand-crafted descriptors without their model retraining. The source codes of this evaluation would be made publicly available.
This brief review introduces the notion of a relativistic multifluid system—a multi-component system with identifiable relative flows—and outlines a set of models for scenarios relevant for different astronomical observation channels. The specific problems used to illustrate the key principles include superfluid hydrodynamics (with relevance for radio and x-ray pulsar timing and gravitational-wave searches), heat flow (connecting to the problem of neutron star cooling and associated x-ray observations) and the coupling between matter and electromagnetism (linking to explosive phenomena like gamma-ray bursts and more subtle issues like the long-term evolution of a neutron star's magnetic field). We also comment on the coupling between matter and radiation, for which the multifluid approach would seem less appropriate. The main motivation of the survey is to illustrate less familiar aspects that come into play in multifluid problems, establish the relevant “language” and provide a platform for more detailed work on these issues.
Rui Zhang, Xiaohao Wei, Vadim A. Kravchinsky
et al.
Abstract Small amplitude or short period geomagnetic anomalies known as “tiny wiggles” (TWs) are often hard to identify because of magnetic signal smoothing in the marine record of geomagnetic reversals. We report here the late Miocene record of geomagnetic reversals in the aeolian red clay sediments of Linxia Basin in China that enables us to identify two TWs. We performed magnetostratigraphy dating and used spectral analysis to distinguish orbital cycles in the records of magnetic susceptibility (MS) and sedimentary grain size (GS) and develop an orbitally tuned age model. The presence of two TWs in the study section, that correspond to C5n.2n‐3 and C5r.2r‐1, is confirmed by orbital calibration of our age model through recognition of eccentricity, obliquity and precession in MS and GS records.