Power system operators need tools for rapid, real-time counterfactual assessments of grid security under fast-changing conditions. Traditional N-1 contingency analysis lacks dynamic evaluation, especially of frequency swings from common faults. This paper introduces a real-time dashboard framework to screen dynamic contingencies. It assumes: (a) the grid starts in a balanced state; (b) faults can occur randomly on any transmission line, temporarily de-energizing and then reconnecting it within about one second; and (c) contingencies are flagged if post-fault transients cause line flows to exceed safety thresholds. The key contributions are: (1) Overload Indicator: a system-wide metric quantifying integrated N-1 dynamic risk from a given state; (2) Scalable Fault Evaluation Algorithm: a linear-scaling method to assess dynamic fault impacts without brute-force simulations; and (3) Risk Estimation: a Cross Entropy Adaptive Importance Sampling method estimating the likelihood of low probability by high risk events, e.g. associated with potential transformer over-current. We demonstrate the framework on the Israeli transmission power grid (IG).
We study a diffuse-interface model for thermally driven phase separation in viscous incompressible mixtures. The system couples a convective Cahn-Hilliard equation for the order parameter with a Stokes subsystem for the velocity-pressure field and a heat equation for the temperature. Temperature enters the bulk free energy through a Landau-type coefficient, while the phase field affects the flow through concentration-dependent density and viscosity. The model serves as a proxy for temperature-triggered condensation-like phase separation; humidity, latent heat, vapor pressure, and capillary forcing are absorbed into the choice of the threshold temperature Θ_S. We motivate the chemical potential through a temperature-dependent Landau free energy and use a regularized auxiliary formulation to prove local-in-time existence of weak solutions. For the numerical analysis, we employ a first-order sequential finite-element discretization of a simplified quasi-static formulation. The heat equation is advanced by implicit diffusion, the variable-coefficient Stokes problem is treated by a Taylor-Hood discretization, and the Cahn-Hilliard bulk derivative is evaluated at the previous time level, so each algebraic subproblem is linear. An isothermal diffusive test confirms mass conservation to roundoff and exhibits monotone discrete-energy decay for the tested parameters. Time-step and mesh-refinement studies show first-order temporal and approximately second-order spatial behavior. The remaining computations provide qualitative, parameter-specific illustrations; no global discrete energy law is claimed for the non-isothermal sequential scheme.
Luminous quasars at the redshift frontier z > 7 serve as stringent probes of super-massive black hole (SMBH) formation and they are thought to undergo much of their growth obscured by dense gas and dust in their host galaxies. Fully characterizing the symbiotic evolution of SMBHs and hosts requires rest-frame optical observations that span spatial scales from the broad-line region (BLR) to the interstellar and circumgalactic medium (ISM and CGM). The James Webb Space Telescope (JWST) now provides the necessary spatially resolved spectroscopy to do so. However, the physical conditions that regulate the interplay between SMBHs and their hosts at the highest redshifts, especially the nature of early feedback phases, remain unclear. We present JWST/NIRSpec integral field unit (IFU) observations of J0313-1806 at z = 7.64, the most distant luminous quasar known. From the rest-frame optical spectrum of the unresolved quasar, we derived a black hole mass of M-BH = (1.63 +/- 0.10)& times;10(9) M-circle dot based on H beta lambda 4861 (H beta) and an Eddington rate of lambda = L/L-Edd = 0.80 +/- 0.05, consistent with previous Mg II lambda 2800-based estimates. J0313-1806 exhibits no detectable [O III] lambda lambda 4959, 5007 emission on nuclear scales (3 sigma upper limit equivalent width of [O III] lambda 5007 < 1.42 & Aring;). Most remarkably, we did detect an ionized gas shell extending out to similar to 1.8 kpc traced by H beta emission that also lacks any significant [O III] lambda lambda 4959, 5007, with a 3 sigma upper limit on the [O III] lambda 5007 to H beta flux ratio of log(10)(F([O III])/F(H beta)) = -1.15. Through photoionization modeling, we demonstrate that the extended emission is consistent with a thin, clumpy outflowing shell where [O III] is collisionally de-excited by dense gas. We interpret this structure as a fossil remnant of a recent blowout phase, providing evidence for episodic feedback cycles in one of the earliest quasars. These findings suggest that dense ISM phases may play a crucial role in shaping the spectral properties of quasars across cosmic time.
Cloud water serves as a chemical reactor where gases and particles undergo chemical transformations and thus is a key component in aerosol-cloud interactions. A total of 535 cloud water samples collected aboard the NASA ACTIVATE HU-25 Falcon (2020-2022) over the northwest Atlantic (U.S. East Coast to Bermuda) are analyzed, and a set of 31 dissolved species spanning major inorganic ions, selected organic acids, and trace elements are used here for source apportionment analysis. The EPA positive matrix factorization (PMF) 5.0 model yields a six-factor solution that explains considerable variability in dissolved solute mass (r = 0.77), with the factors being sea salt (81.3% of reconstructed mass), secondary aerosol (12.2%), traffic/combustion (5.2%), metal-enriched dust (0.9%), aged dust (0.3%), and an industrial/metallurgical factor (0.07%). Seasonal and spatial patterns showed strong sea salt mass contributions in all months, but especially in winter enhanced aged dust influence near Bermuda in June, and larger relative contributions of metal and traffic/combustion-related factors near the coast. Concentration-weighted trajectory maps link the dust factor to trans-Atlantic transport from North Africa and most other factors to export from the eastern United States. Overall, the results show that mass-based cloud water chemistry is strongly weighted toward larger, highly hygroscopic particles, while still retaining clear signatures of continental pollution and long-range dust transport.
Microplastic particles are emerging as significant vectors for antibiotic resistance genes (ARGs), exacerbating the global antibiotic resistance crisis. This review provides a comprehensive analysis of how microplastics interact with ARGs, their environmental dissemination, and the associated risks. Microplastics serve as ideal surfaces for antibiotic-resistant bacteria (ARB) and extracellular ARGs carried by mobile genetic elements, fostering the formation of biofilms that amplify gene transfer through both vertical and horizontal pathways. These biofilms not only enhance microbial survival but also act as reservoirs where antibiotics accumulate, creating selective pressures that further enrich ARB populations. Moreover, co-selection mechanisms involving heavy metal resistance genes may accelerate ARG proliferation in polluted environments. The association of microplastics with ARGs is particularly pronounced in wastewater, where concentrations range from 10⁶ to 10¹¹ copies/L, significantly higher than in natural aquatic environments (1 to 10⁹ copies/L) due to high contamination levels and the inefficiency of current wastewater treatment technologies. In terrestrial ecosystems, microplastics-ARGs are prevalent due to antibiotic use in agriculture and livestock production, as well as the widespread application of sewage sludge on farmland. Additionally, airborne particulate matter, including microplastics, has been identified as a potential but understudied vector for ARG transmission. The environmental and public health implications of microplastics-ARGs are profound, potentially leading to the emergence of antibiotic-resistant pathogens and hard-to-treat infections. This review provides a comprehensive and systematic overview of the current pollution status in common ecological environments, providing guidance for subsequent research on ARGs and microplastics. At the same time, it emphasizes the urgent need to study the role of microplastics in facilitating the transfer of ARGs between microorganisms, as well as the migration, fate, and impact of ARGs carried by microplastics in the air. Filling these knowledge gaps is crucial for slowing the spread of antibiotic resistance and maintaining global health.
