ABSTRACT The orbital decay of binary systems is a critical process for understanding the evolution of massive binary black holes (MBBHs) and binary star formation. Performing high-resolution three-dimensional magnetohydrodynamic simulations, we investigate a binary system that accretes gas from an infalling envelope analogous to the collapse of molecular cloud cores in the context of binary star formation. Our simulations reveal the presence of outflows/jets launched from both the circumstellar (mini) discs and the circumbinary disc (CBD). The magneto-rotational instability is also excited within the CBD. These magnetic processes efficiently transport angular momentum in the gas surrounding the binary and thereby drive orbital decay, while a purely hydrodynamical model exhibits orbital expansion. The decay rate reaches $\sim 0.3{-}0.7~{{\ \rm per\ cent}}$ per orbital period, depending on the initial magnetic field strength. By appropriately scaling these numerical results, we propose a new mechanism for MBBH mergers within a Hubble time, overcoming the bottlenecks encountered at separations near the final parsec scales. Additionally, we present a formation scenario for close twin binary star systems, emphasizing the significant role of magnetic processes in driving orbital evolution across various astrophysical systems.

Context. Traditionally, high-mass X-ray binaries (HMXBs) are considered atypical products of close binary evolution where the primary component of the progenitor binary has formed a compact object through a supernova explosion, shedding a significant portion of the overall binary mass in the process. This rapid mass loss from the system results in an extra peculiar systemic velocity with respect to the system’s local standard of rest. Moreover, there is also a contribution to the peculiar systemic velocity from a natal velocity kick, which is imparted to the compact object upon formation. Provided that the binary remains bound, both the rapid mass loss and the natal kick cause the system to gain a significant systemic velocity of typically several tens of kilometers per second with respect to its standard of rest. This makes the system rapidly leave the environment where it was born. This classical picture has now been challenged by discoveries of systems with low or negligible peculiar systemic velocities, arising from more exotic supernova types, such as electron-capture or ultrastripped supernovae. These supernovae explode with a low degree of asymmetry and only eject a small amount of mass, yielding low peculiar systemic velocities. Aims. We investigate the occurrence of HMXBs in open clusters and, if they are present, use the cluster parameters to constrain the system properties and the physics of the supernovae that produced them. Methods. We used Gaia astrometry data and derived catalogs to examine whether known HMXBs are physical members of open clusters, using membership criteria based on positions, parallaxes, and proper motions. Results. We identify four HMXB and HMXB candidates that are members of open clusters: IGR J16465-4507 in CWNU 2672, SGR 0755-2933 in HSC 1981, HD 119682 in NGC 5281, and NGC 6649 9 in NGC 6649. Their presence in open clusters implies that they were born without significant systemic kick, which provides important constraints to supernova explosion mechanisms in close binary systems. The residual tangential velocities we derive (0.9 ± 0.4 km/s for SGR 0755-2933 and 2.6 ± 0.5 km/s for IGR J16465-4507) provide direct observational evidence for the ultralow kick mode recently identified in Be X-ray binary populations, demonstrating that such systems can remain gravitationally bound to their parent clusters

Formation of classical Be-stars of the early spectral subclass in the case of nonconservative mass transfer in close binary systems

Enterprise financial systems are undergoing rapid transformation due to increasing regulatory complexity, high-volume digital transactions, and the shift toward cloud-native architectures. Traditional ERP financial modules rely heavily on rule-based validations and manual reconciliation processes, limiting their ability to detect anomalies, prevent revenue leakage, and adapt dynamically to evolving compliance requirements. Despite the robustness of platforms such as SAP S/4HANA, financial operations in large enterprises continue to depend on static validations, post-period reconciliation, and manually supervised exception handling. These constraints increase fraud exposure, revenue leakage risk, and financial close cycle duration. This research introduces the Autonomous Financial Operations Framework (AFOF), a cloud-native, AI-augmented architecture that embeds intelligent automation directly within ERP transactional workflows. The framework integrates: The extensibility and microservices capabilities of SAP Business Technology Platform Behavior-driven service modeling via SAP ABAP RESTful Application Programming Model (RAP) Embedded machine learning services for anomaly detection and predictive analytics The proposed framework leverages the extensibility of SAP S/4HANA, the cloud capabilities of SAP Business Technology Platform, and the service-oriented programming paradigm of SAP ABAP RESTful Application Programming Model (RAP) to create a self-optimizing financial operations layer. The architecture introduces five core components: An Intelligent Posting Validation Engine using behavior-driven RAP logic. An AI-based Anomaly Detection Module for financial irregularities. Automated reconciliation services for high-volume subledger environments. Predictive revenue leakage analytics tailored for subscription-based monetization systems. A secure event-driven extension layer supporting scalable enterprise integration. A controlled enterprise-scale simulation was conducted using synthetic financial datasets modeling high-volume subscription billing environments (10–50 million monthly transactions). Comparative benchmarking against traditional rule-based ERP controls demonstrated: 43% reduction in financial close cycle duration 37% improvement in anomaly detection precision 52% reduction in manual reconciliation effort 28% decrease in revenue leakage exposure 31% faster exception resolution turnaround time Latency measurements confirmed that embedded AI validation introduced less than 8 ms average transactional overhead, preserving ERP performance integrity. Unlike conventional ERP enhancements that operate as external monitoring tools, the AFOF embeds machine learning–assisted controls directly within transactional workflows. This approach enables real-time compliance validation, adaptive financial risk scoring, and automated exception resolution, significantly reducing operational overhead and financial exposure. Performance modeling demonstrates measurable improvements in financial close cycle time, anomaly detection accuracy, and reconciliation efficiency when compared to legacy rule-based systems. This research contributes a scalable and reusable architectural model for AI-enabled financial automation in regulated industries, including telecommunications, digital commerce, healthcare billing and large-scale enterprise services. By integrating intelligent automation within mission-critical ERP systems, this research advances enterprise cybersecurity resilience, financial governance, and digital economic infrastructure modernization.

Type II-P supernovae (SNeII-P) are the most common class of core-collapse SNe in the local Universe and play critical roles in many aspects of astrophysics. Since decades ago theorists have predicted that SNeII-P may originate not only from single stars but also from interacting binaries. While ∼20 SNII-P progenitors have been directly detected on pre-explosion images, observational evidence still remains scarce for this speculated binary progenitor channel. In this work, we report the discovery of a red supergiant progenitor for the Type II-P SN2018gj. While the progenitor resembles those of other SNeII-P in terms of effective temperature and luminosity, it is located in a very old environment, and SN2018gj has an abnormally short plateau in the light curve. With state-of-the-art binary evolution simulations, we find these characteristics can only be explained if the progenitor of SN2018gj is the merger product of a close binary system, which developed a different interior structure and evolved over a longer timescale compared with single-star evolution. This work provides the first compelling evidence for the long-sought binary progenitor channel toward SNeII-P, and our methodology serves as an innovative and pragmatic tool to motivate further investigations into this previously hidden population of SNeII-P from binaries.

Abstract A significant fraction of stars experience close interactions, including collisions resulting from gravitational encounters and mergers within close binary systems. These processes can produce more massive stars that may give rise to relatively rare objects such as blue stragglers. Distinguishing the outcomes of collisions and mergers is challenging yet essential for interpreting observations. This study utilizes the magnetohydrodynamics code AREPO to simulate collisions and mergers of 5–10 M ⊙ main-sequence stars, systematically comparing the properties of the resulting products. Both collisions and mergers yield more massive, strongly magnetized, rapidly and differentially rotating stars with cores enriched in hydrogen, but notable quantitative differences emerge. Merger products exhibit core hydrogen fractions up to 10% higher than those of collision products. In both scenarios, turbulent mixing amplifies magnetic field energies by 9–12 orders of magnitude. However, magnetic fields in small-impact-parameter collision products display small-scale reversals that may dissipate over time, whereas merger products and large-impact-parameter collision products develop large-scale ordered, potentially long-lived magnetic fields. Additionally, only merger products display magnetically driven, bipolar outflows with radial velocities up to 300 km s −1 . These distinctions may result in different long-term evolutionary outcomes, which warrant further investigation in future studies.

Global population growth necessitates sustainable food systems, positioning Circular Bioeconomy as a key transition framework. In Oaxaca, Mexico, semi-intensive tilapia aquaculture faces economic viability issues due to a critical reliance on expensive external commercial feeds. This study proposes a "Backyard Integrated System" specifically designed for rural contexts with limited capitalization, connecting traditional entomophagy with aquaculture to reduce operational costs and close nutrient cycles. Using a mixed-method approach, we first conducted a sociocultural diagnosis (n = 140), revealing a 97.14% acceptance of insect consumption. Subsequently, to validate technical viability, a long-term (280-day) feeding trial was conducted using standardized insect meals (Tenebrio molitor and Acheta domesticus) as total substitutes (100%) for commercial feed in Nile tilapia (Oreochromis niloticus) diets. Results showed a Feed Conversion Ratio (FCR) of 1.61-1.62, comparable to the commercial control (p > 0.05), while significantly enhancing fillet protein content. Crucially, microbiological analysis confirmed the absence of pathogens in the final product, empirically validating the safety of the waste-to-feed cycle. Consequently, this strategy ensures food sovereignty, decouples producers from volatile external markets, and offers a scalable solution for community resilience without compromising food safety.

Dawson’s contributions to astronomy included photometric studies of the Delta Scuti Star FG Virginis, W Ursae Majoris variables, component interactions in close binary systems, and timing variations for exoplanets during stellar transits.

Abstract The third body is expected to shape the formation and evolution of close binary systems. In this work, we develop a method to detect and characterize the tertiary companion around eclipsing binaries through the combined analysis of eclipse timing variation, Hipparcos, and/or Gaia astrometry. This method allows us to determine both the true mass and the inclination of the tertiary body that inferred from light-travel time effect. For the massive B-type binary V Pup, we do not confirm the previously reported 5.47 yr signal; instead, we identify a longer period of 14 yr. The orbital semimajor axis and mass of the outer body are revised to a C = 17.88 − 0.15 + 0.15 au and M C = 7.73 − 0.14 + 0.14 M ⊙ , confirming it as a promising stellar-mass black-hole candidate for further follow-up study. For the tertiary of the contact binary CY Ari, we obtain P C = 5.40 6 − 0.016 + 0.017 yr, e C = 0.52 6 − 0.027 + 0.032 , I C = 85.6 − 6.5 + 7.8 °, and a true mass of M C = 0.64 0 − 0.029 + 0.029 M ⊙ , supporting the white dwarf hypothesis proposed in previous study. The orbits of both systems are nearly edge-on ( I = 90°), implying that they may form in a coplanar environment. We highlight the advantages of our method for detecting dark companions in binary and triple systems.

Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM)-based 3D printing technology is widely used in the manufacture of denture bases due to its precision and efficiency. However, the quality of the printed results is greatly influenced by printing parameters, especially the exposure time per layer that plays a role in the polymerization process of photopolymer resin. This study aims to analyze the effect of exposure time per layer on the dimensional accuracy and flexural strength of denture bases fabricated using Open System 3D Printing technology. This laboratory experimental study used a post-test only control group design. Denture bases were printed using an open system with exposure time variations of 4.5, 5, and 5.5 seconds, and compared with Close System 3D Printing and heat-polymerized acrylic resin (RAPP). Dimensional accuracy was measured in length, width, and height parameters, while flexural strength was tested using the three-point bending test method. Statistical analysis was performed using Welch's ANOVA test and Tukey's extended test (α = 0.05). The results showed that exposure time per layer had a significant effect on dimensional accuracy and flexural strength (p = 0.000). In the open system, the highest length accuracy value was obtained at an exposure time of 5.5 seconds (64.99 ± 0.07 mm), followed by 4.5 seconds (64.98 ± 0.09 mm) and 5 seconds (64.94 ± 0.05 mm). The highest flexural strength value in the open system was obtained at an exposure time of 4.5 seconds (68.90 ± 1.27 MPa), followed by 5.5 seconds (67.29 ± 1.49 MPa) and 5 seconds (66.08 ± 2.32 MPa). The closed system group showed the highest flexural strength value (90.61 ± 2.72 MPa), while RAPP was 73.76 ± 3.60 MPa. It was concluded that the exposure time setting per layer plays an important role in optimizing the dimensional accuracy and mechanical properties of 3D printed denture bases

The sustainability of cropping systems is linked to their circularity, which is their ability to close resource cycles such as carbon and nitrogen through strategies for managing crop residues, byproducts, and other inputs. Here, we investigate three crop rotations-business-as-usual (BAU), vegan, and integrated crop-livestock systems (ICLS)-varying in livestock integration, crop residue fate, and human diet sustained. Under ten climate change scenarios, we compare their impacts on multiple ecosystem services during 24 years over 541,800 ha in Belgium using a validated crop model. All three circularity scenarios are found to be net greenhouse gas (GHG) emitters, with increasing intensity under climate change. The BAU system, favoring cash crops such as sugarbeet or potato, demonstrates the highest productivity, which, however, is highly variable across years and comes with greater environmental impacts such as GHG emissions (+45% and +23% compared to ICLS and Vegan in average-i.e., across all sites and climate scenarios). The Vegan system has lower carbon sequestration than the ICLS due to the lack of pasture and livestock, which, however, is partly offset by the regular incorporation of crop residues into the soil. Finally, ICLS, which include temporary pastures and sheep, demonstrate intermediate productivity levels compared to the other systems. However, they offer the greatest stability and resistance to extreme weather (+43% and +86% for stability compared to BAU and Vegan, in average), with better environmental performance. Therefore, our study reveals the benefits of crop-livestock systems in terms of climate change adaptation, through stability and resistance to extreme climate events, and mitigation, through soil carbon sequestration and reduced greenhouse gas emissions and nitrate leaching. Moreover, our findings highlight the critical links between farm-level circularity, soil-crop feedbacks, human diet, and climate change.

Abstract This study presents a comprehensive investigation of orbital period (OP) variations in 37 low mass ratio contact binaries (LMRCBs) (q < 0.25). New minima times (MTs) were calculated from TESS and SuperWASP observations (a total of 452 minima for 37 systems), supplemented by values collected from the literature. For each target, Observed (O)−Calculated (C) diagrams were constructed to examine both long term (secular) trends and short-term cyclic variations. Our findings reveal that most systems exhibit significant long-term period evolution, while some display periodic modulations that can be interpreted as the Light-Time Effect (LITE) caused by a tertiary companion, or alternatively, these modulations may result from magnetic activity. In the constructed q −dP/dt diagram, it was observed that the rate of decrease in OP varied over a wider range than the rate of increase in OP. Additionally, Hertzsprung-Russell (HR), logMtot−logJ , and q−Js/Jo diagrams were generated to explore the evolutionary states of the candidate systems. These results provide compelling evidence that LMRCBs may represent dynamically unstable configurations, offering crucial insights into the late evolutionary stages of close binary systems.

One of the largest sources of uncertainty in the predictions of stellar models comes from the internal transport mechanisms. In close massive binaries, previous theoretical studies suggest that tides consistently boost chemical mixing. However, observations do not reveal any clear period-nitrogen enrichment trend, challenging these predictions. In addition, comprehensive examinations of the interplay between tidal interactions, angular momentum, and chemicals transport have so far been very scarce. Our goal is to investigate the interplay between tidal interactions and rotational mixing, and the impact of the angular moment transport (AMT) assumptions. We also aim to tackle the question of whether tidal interactions enhance or suppress chemical mixing. We computed grids of binary models with various AMT treatments at solar metallicity. In order to independently assess the role of tidal interactions, we systematically computed model variations of single stars with identical initial conditions. Our investigations reveal that tidal interactions can either enhance or suppress mixing relative to single-star models with identical initial conditions, and that the outcome is highly sensitive to the adopted AMT assumptions. We identify a key contrast between the two types of computed models: in close systems subject to tides, magnetic models predict that the mixing efficiency is mostly determined by the orbital configuration, whereas in hydrodynamic models it also depends on the assumed initial velocity. As a result, hydro models may display non-monotonic period–enrichment trends, or even period-enrichment correlations. These results highlight the importance of the AMT assumptions in modeling binaries with tidal interactions, notably in the context of the chemically homogeneous evolution channel. The sensitivity of the predictions of hydro models to initial conditions extends the size of the period-enrichment parameter space they cover, allowing them to accommodate for peculiar observed systems, i.e., with mild enrichment at short periods or high enrichment at longer periods.

Abstract Von Zeipel–Lidov−Kozai (ZLK) oscillations, induced by bound, perturbative companions to white dwarfs (WDs), have been suggested as a dynamical mechanism that may contribute to WD pollution. To trigger ZLK oscillations, however, a three-body system must reach a sufficiently large mutual inclination between orbits. The occurrence of these high-mutual-inclination configurations can be curtailed by dissipative precession at the protoplanetary disk stage, which pushes exoplanet-hosting close binary systems toward preferential orbit–orbit alignment. In this work, we constrain the fraction of WDs with binary companions that can undergo ZLK-driven pollution given the effects of dissipative precession. To accrete pollution via ZLK oscillations, a WD binary system must be sufficiently inclined and the characteristic timescale of the oscillations must be sufficiently short to perturb material within the WD’s cooling age. Considering a sample of 4400 known WD/main-sequence binaries, we find that 50%–70% have favorable parameters for ZLK pollution, depending on the orbital separation of the polluting body. While the conditions for oscillations are favorable, the tendency for ZLK to result in massive but more infrequent polluters likely restricts the rates of ZLK-induced pollution among the observed population. In general, dissipative precession is a limiting factor in pollution rates for more closely separated binaries (initial separations <500−800 au), while ZLK timescale constraints are most limiting for wider binaries.

Waste valorisation has become a key strategy for applying circular economy principles in the agro-industrial field. This study investigated the territorial implementation of the waste composting on a territorial scale. The wastes considered were the post-processing orange waste, spent olive oil pomace, and spent wine grape pomace. Their potential use as soil amendments across the provinces of Sicily was assessed through a GIS-based analysis, taking into account nitrogen (N) application constraints. Moreover, a cascade valorisation scheme was also evaluated: post-processing orange waste was first used as animal feed, and the remaining fraction was directed to composting; olive pomace was first sent to pomace oil extraction mills, and the residual material was subsequently used for composting. Results indicate that N inputs derived from composted residues remain below legal thresholds in all provinces, with relative contributions ranging from 38% to 92% of the regulatory limits. Spatial variability in nitrogen availability reflects the territorial distribution of agro-industrial activities, highlighting the importance of localised management strategies. These findings demonstrate that composting, combined with cascade valorisation, is an effective pathway to close nutrient cycles, reduce waste generation, and support sustainable biomass management in regional agri-food systems.

Abstract Double white dwarf (DWD) binaries are natural outcomes of binary stellar evolution and key sources for future space-based gravitational wave (GW) observatories such as Laser Interferometer Space Antenna ( LISA ). We investigate how different binary interaction channels shape the physical and orbital properties of DWD systems, focusing on component masses, orbital separations, core compositions, and mass transfer rates. Using the binary population synthesis code compas, we evolve $10^7$ binaries with physically motivated initial distributions of binary parameters. Our simulations reproduce the strong bimodality in the final orbital separations, including a pronounced deficit of systems around 100–500 $\mathrm{R}_\odot$ , arising from distinct evolutionary pathways: wide DWDs predominantly originate from stable Roche lobe overflow (RLOF), while close DWDs form through unstable RLOF leading to at least one common envelope (CE) phase. Moreover, we show that the core compositions of WDs provide a powerful tracer of evolutionary history: He-core WDs are strongly concentrated in close systems, whereas CO-core WDs span the full separation range and exhibit a small mass gap in wide binaries. We further identify a correlation between the donor mass transfer rate and the final orbital separation, highlighting the impact of non-conservative mass transfer on the resulting orbital configuration of DWD systems. These results underscore the links among evolutionary channels, chemical composition, and mass transfer rates; thereby provide a unique framework for interpreting Gaia DWD samples and forecasting the joint electromagnetic and GW population accessible to LISA .

Abstract Recent work by Piilonen et al. (2025) documents the occurrence of a dike of novel composition in the late-Paleozoic Ice River Alkaline Complex of southeastern British Columbia, Canada. The dike is notable for its mineralogical diversity (28 species documented to date), high abundance of Ti (occurring mainly as titanite, anatase, and brookite), and evidence of Ti mobilization within the close dike system. The occurrence of pseudomorphs after titanite, consisting mostly of anatase, calcite, and minor brookite, are common. These pseudomorphs are investigated here in detail to better constrain the behavior of Ti (and Nb) during, and subsequent to, dike emplacement. Pseudomorph formation is shown to occur by the reaction CaTiOSiO4 (titanite) + HCO3− + 2H2O ↔ CaCO3 (calcite) + TiO2 (anatase) + H4SiO4 + (OH)−, which follows a reaction front that systematically migrates from the edge toward the core of the primary titanite. As primary titanite breaks down, both Ti and Ca are conserved within the pseudomorph volume. Cathodoluminescence imaging (by electron microscopy) shows that growth features such as sector and oscillatory zoning in anatase are common within the samples investigated. The occurrence of such features is consistent with the growth of pseudomorphic phases having occurred in a solution into which Ti and Ca were dissolved and mobilized on the micrometer scale, immediately following initial titanite destabilization. In the later stages of dike evolution, the introduction of fluids rich in Na-Al-Si-Fe dissolve both pseudomorphic anatase and calcite, replacing them with aegirine, natrolite, and minor secondary titanite; Ti is remobilized on the centimeter-scale and partially removed from the pseudomorph volume, precipitating as secondary anatase elsewhere within the dike.

Hot stars born as rapid rotators are expected to induce meridional currents that mix hydrogen from the envelope into the core and return CNO-cycle processed material to the envelope, which should enhance the N at the surface at the expense of C and possibly also O depending on the ambient conditions. But the photospheric C and N abundances could also be influenced by mass transfer in a close binary system which spins up the mass gainer and deposits either processed or unprocessed material to its surface depending on just how much material has been peeled off the mass donor. We focus on the chemical composition of Be star photospheres to infer the present and past evolution of rapidly rotating early B stars. To mitigate the effects of gravity darkening and photospheric line blending on the abundances, we chose 8 Be stars with low vsin i that have good high-resolution FUV spectra in the IUE archive. We carried out a conventional NLTE abundance analysis of selected N iii, N i, and C iii lines in the FUV spectral region. We find clear evidence that the C iii 1176 Å multiplet is weak in the core region in most program stars, suggesting CNO processing. However, in all cases we infer a N abundance that is solar or less, raising a conundrum as to what happened to the “missing C.” Since a similar pattern of weak C yet normal N is also found in the mass gainer in some Algol binaries, there appears to be an emerging challenge to explain this apparent abundance anomaly. We speculate that the excess N from CNO processing might be converted into O (and perhaps on to Ne) by fusion with He in the hot but low-density regions either in the trail of ashes just outside the receding carbon-fusing core, or in He-shell flash regions, of a highly evolved mass loser in its final stage of mass transfer.

Women with Disabilities (WWDs) are more susceptible to victimisation than those without disabilities. Extant literature showed the enormous challenges faced by people with disabilities, yet the social contexts enabling the victimisation of WWDs remain less studied. Therefore, this study examined the victimisation experiences of WWDs and the social contexts that exposes them to those victimisations. Routine activities theory and exploratory research design were adopted. Twelve in-depth interviews were conducted with victimised WWDs who were reached through the snowball method, while eight purposive key informant interviews were conducted with one Nigerian Police Officer as a state actor and seven non-state actors drawn from the Disabled People Organisations. Data were subjected to inductive and narrative analysis. WWDs experienced physical and non-physical victimisations. Negative attitudes from close networks and social support systems resulted from the metaphysical attributions of WWDs as depraved and demonic, created the social contexts that expose them to victimisation. The study concludes that the negative attitudes and beliefs towards WWDs exposed them to victimisation which are not isolated incidents but often repeated simultaneously in multiple forms. Therefore, both state and non-state actors need to strengthen the enacted disability laws and institutions for effective enforcement and prosecution of perpetrators

Abstract Helium white dwarfs (He WDs) are end products of low-mass red giant donors in close binary systems via stable mass transfer or common envelope evolution. At the end of stable mass transfer, there is a well-known relation between the He WD mass and orbital period. Although this relation has been widely investigated, the influence of different types of opacity at low temperatures is ignored. In this work, we modeled the evolution of white dwarf (WD) binaries with the stellar evolution code MESA and two types of opacity at low temperatures from Ferguson et al. and Freedman et al. We investigated the relation between the WD mass and orbital period and compared these results with observations. We find that the relation derived from the opacity of Freedman et al. is below that from the opacity of Ferguson et al., and the relation derived from the opacity of Freedman et al. can better explain the observations. In addition, we provided fitting formulae for the relations derived from the opacity of Freedman et al. at different metallicities.