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Fish assemblage patterns influenced by nutrient levels and thermal effluent from power plants in the lower reaches of Berung and Wadas Rivers, Serang Regency, Banten, Indonesia
No full textThe downstream of the Berung and Wadas Rivers in Serang Regency, Banten Province, Indonesia, possesses economically significant fishery resources. However, these waters face environmental threats, notably thermal effluent from a Steam Power Plant. This study aimed to analyze fish species diversity and habitat conditions by examining the relationship between fish assemblages and key physicochemical factors, specifically temperature and nutrient levels. The study was conducted in January 2020 at six sampling stations representing riverine, estuarine, and marine zones. Fish samples were collected using gillnets, while physicochemical parameters (including temperature, nutrients, DO, salinity, and pH) were measured concurrently. Fish diversity was evaluated using the Shannon index, and the relationship between fish assemblages and environmental variables was analyzed using Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA). A total of 63 individual fishes, comprising 11 species from 10 families, were recorded. The squaretail mullet (Ellochelon vaigiensis) was the dominant species (67%). Fish diversity varied significantly across stations. Stations 1, 2, and 6, located in productive estuarine areas, exhibited higher fish diversity. Conversely, Station 5, situated near the power plant's thermal discharge, recorded elevated temperatures (37.5°C) and low fish diversity, indicating negative impacts from thermal pollution. The findings confirm that the thermal effluent acts as a pollutant, creating environmental instability for the aquatic biota. Therefore, improved waste management strategies are necessary to mitigate the ecological impacts in this area
Gendered media representation and political leadership: The case of Khofifah Indar Parawansa in Indonesia’s 2024 election
No full textThis study examines how gendered media framing shapes public perceptions of female political leadership in Indonesia, focusing on Khofifah Indar Parawansa during the 2024 East Java gubernatorial election. Although women’s political participation has increased through affirmative action and the growing visibility of female leaders, gender stereotypes continue to influence political communication. Using Robert Entman’s framing theory and a qualitative content analysis of news reports published by Mediaindonesia.com, this research identifies the dominant frames used to portray Khofifah’s leadership. Four key frames emerged: competence, religiosity, domesticity, and personal traits. The competence and religiosity frames emphasize administrative experience, policy achievements, and moral credibility, enhancing her legitimacy as a regional leader. Conversely, the domesticity and personal traits frames highlight nurturing qualities, emotional sensitivity, and maternal identity, revealing the persistence of gendered expectations that shape interpretations of female leadership. These combined narratives demonstrate an ambivalent pattern in which media coverage simultaneously strengthens women’s political visibility while reinforcing traditional gender norms. The study contributes to discussions on gendered mediation in Southeast Asian political communication and underscores the need for more gender-sensitive reporting practices to support equitable representation in regional executive elections
Dynamic Game Modeling and DNAS² Framework for Dual-S Security in Internet of Vehicles
No full textSecurity is paramount for the Internet of Vehicles (IoV), leading to the proposal of the “Dual S” architecture integrating functional safety and cybersecurity. However, the complex interplay—encompassing resource competition, conflictual cooperation, and interaction—between these two domains lacks a rigorous analytical framework. To bridge this gap, this paper introduces “DNAS²,” a novel game-theoretic model for IoV security. DNAS² comprises two interconnected components: (1) an internal cooperative game that formalizes the “S² Alliance,” where collective rationality supersedes individual interests. We provide a solution method for allocation equilibrium, proving it drives the endogenous security system toward Pareto optimality. (2) an external non-cooperative attack-defense game that accounts for dynamic adversarial strategies and information asymmetry. For this model, we derive equilibrium solutions that furnish the mathematical foundation for optimal defense strategies and payoff predictions. Our work provides a unified analytical tool for optimizing IoV security design. Future research will focus on model refinement and extension to evolutionary game scenarios
Afterglow linear polarization signatures from steep GRB jets: Implications for orphan afterglows
No full textGamma-ray bursts (GRBs) are the strongest explosions in the Universe, and are powered by initially ultra-relativistic jets. The angular profile of GRB jets encodes important information about their launching and propagation near the central source, and can be probed through their afterglow emission. Detailed analysis of the multiwavelength afterglow light curves of recent GRBs shows evidence of an extended angular structure beyond the jet’s narrow core. The afterglow emission is determined by the jet angular structure, our viewing angle, and the magnetic field structure behind the shock, often leading to degeneracies when considering the light curves and broadband spectrum alone. Such degeneracies can be lifted with joint modeling of the afterglow light curves and polarization. In this work we studied the evolution of the afterglow linear polarization and flux density from steep core-dominated GRB jets, where most of their energy resides within a narrow core. We explored the dependence of the light and polarization curves on the viewing angle, jet angular energy structure, and magnetic field configuration and provide an analytical approximation for the peak polarization level, which occurs at a time close to that of a break in the light curve. Finally, we demonstrated how our results can be used to determine the nature of orphan GRB afterglows, distinguishing between a quasi-spherical dirty fireball and a steep jet viewed far off-axis, and applied them to the orphan afterglow candidate AT2021lfa detected by the Zwicky Transient Facility (ZTF)
Flashing fast: Characterising the 2025 outburst of MAXI J1957+032
No full textContext. MAXI J1957+032 is an accreting millisecond X-ray pulsar that shows brief, recurrent outbursts within an ultra-compact ≈1 h orbit.
Aims. We characterised the X-ray timings and spectral and optical properties during the 2025 outburst and measured the long-term spin evolution relative to its previous 2022 outburst.
Methods. We analysed X-ray observations from XMM-Newton, Swift, and NuSTAR, together with contemporaneous optical photometry obtained with LCO during the 2025 outburst. X-ray timing analysis included standard epoch-folding and coherent searches, while energy-resolved pulse profiles were studied through harmonic decomposition. Spectral fits used absorbed thermal–Comptonisation models complemented with a soft blackbody component, whose emission radius suggests that the blackbody emission originates from a hotspot on the neutron star surface.
Results. Coherent pulsations were detected at ν ≈ 313.6 Hz, with no measurable frequency derivative within the XMM-Newton exposure. Via comparisons with the 2022 outburst, we find a long-term spin-down of Hz s−1, consistent with magnetic dipole braking during quiescence. The pulse shape is almost sinusoidal, showing significant power at the fundamental, second, and fifth harmonics. The fractional amplitude decreases with increasing flux and exhibits soft lags extending to a few keV. The X-ray spectrum between 0.5 and 10 keV is well reproduced by a thermal–Comptonised continuum with photon index Γ ≈ 2.4, plus a cool blackbody with kT ≈ 0.23 keV. No reflection or Fe-line features are detected. Assuming Rm ≲ Rco, the magnetic field is limited to Bs ≈ (0.5–3)×108 G (for d = (5 ± 2) kpc and truncation factor ξ = 0.3–0.5), lower than the upper limit implied by the secular spin-down (Bp ≲ 109 G), possibly indicating a mildly leaky propeller regime. The optical and infrared (OIR) emission follows the neutron-star branch of the LOIR–LX relation, consistent with X-ray reprocessing in a compact accretion disc. The optical spectral energy distributions are broadly flat, supporting irradiation-dominated disc emission, and an early red excess suggests a jet contribution during the initial hard X-ray phase. A delayed optical peak relative to the X-rays may reflect the outward propagation of a heating front through the disc, consistent with rapid disc evolution in short-lived outbursts
Photometric and spectroscopic variability of the blue supergiant
No full textContext. The post-main-sequence evolution of massive stars remains poorly understood, particularly in the case of blue supergiants. As key drivers of the dynamical and chemical evolution of galaxies, massive stars warrant detailed investigation during this complex evolutionary stage. Hot supergiants exhibit pronounced photometric and spectroscopic variability, typically in the form of quasi-periodic rather than strictly periodic variations.
Aims. We investigated the variability patterns of the evolved B-type star ρ Leo to determine its properties, identify the underlying physical processes, and constrain its evolutionary stage. We combined extensive long-term datasets of spectroscopic and photometric observations from various sources. These include data from the TESS and Kepler space telescopes, as well as observations from the 1.5 m telescope in Estonia.
Methods. We analysed the data using the generalized Lomb–Scargle periodogram, the Lomb–Scargle periodogram with pre-whitening, and the weighted wavelet Z-transform. To determine the fundamental parameters of ρ Leo, we fitted synthetic line profiles computed with the FAS
Mais qui vide l’Antarctique dans l’océan à la grande cuillère ?
No full textPourquoi étudier l’Antarctique ? L’alpiniste George Mallory vous aurait certainement répondu avec flegme parce qu’il est là ! Alors que le commandant Jean-Baptiste Charcot plutôt pourquoi pas ? En réalité, l’Histoire montre que c’est avant tout le goût de l’exploration et la soif de connaissances qui ont nourri notre intérêt pour cette terra incognita inhospitalière. Les recherches sur le continent blanc ont connu leur heure de gloire à la fin des années 80 lorsque les glaces millénaires du continent, véritable livre ouvert sur les climats passés, ont permis d’établir le premier lien avéré entre la concentration de gaz à effet de serre dans l’atmosphère et la température moyenne de la planète, révolutionnant alors la climatologie moderne. La découverte récente de la contribution de l’Antarctique au niveau des mers, et son futur très incertain, alimente aujourd’hui une part croissante des recherches. Les satellites révèlent, en effet, que l’Antarctique contribue à l’élévation du niveau des mers depuis plusieurs décennies via la fonte massive induite par l’océan sous les terminaisons flottantes de ses glaciers. Pour autant, les rôles respectifs des influences humaines et naturelles dans cette fonte ne sont pas clairement établis, alors que le succès des politiques d’adaptation pourrait en dépendre. Les travaux présentés ici apportent de nouveaux éléments de réponse sur ces rôles
Comparative Evaluation of Machine and Deep Learning Models for Air Quality Index Prediction in Jaipur, India
No full textAir pollution is an important environmental and public health challenge, therefore, accurate Air Quality Index (AQI) forecasting is important for timely mitigation. This study predicts AQI in Jaipur, India using seven machine learning and deep learning-based models i.e., Multiple Linear Regression (MLR), Random Forest (RF), Support Vector Regression (SVR), XGBoost, Adaboost, Artificial Neural Network (ANN), and Convolutional Neural Network (CNN). For this purpose, two years of hourly data from three monitoring sites were used, with preprocessing to address missing values and outliers. Key pollutant and meteorological variables were selected using Pearson's correlation coefficient vaules. Models were evaluated under three scenarios: pollutant parameters only (Case 1), meteorological parameters only (Case 2), and a combined dataset (Case 3). Performance was assessed using indices such as R2 and RMSE. Case 3 consistently produced the most accurate predictions, with Site 2 reflecting the best overall results. Among all models, XGBoost outperformed achieving R2 values of 0.77-0.95 and RMSE values of 16.96-20.98 across the three sites. The study demonstrates that XGBoost is a reliable approach for AQI forecasting and provides useful insights for air quality management and policymaking in rapidly urbanizing cities like Jaipur
Investigating the Use of Pandan Leaves (Pandanus Amaryllifolius) as a Component in Producing Exterior Wall Fiber Cement Board
No full textThis study explores the use of Pandanus amaryllifolius leaves in an eco-friendly mixture for manufacturing fiber-cement boards intended for exterior wall construction. This study began with the tensile properties of Pandan leaves, which were found to exhibit excellent mechanical properties and resistance to deformation. The fibers were found to have suitable textures for bonding with their matrices and uniform distribution, as confirmed by scanning electron microscopy analysis. The experiment used fiber-cement boards with fiber contents of 0%, 3%, 6%, and 9%. All samples met commercial density, water absorption, and moisture content specifications. Fiber component enhancement exhibited positive flexural characteristics, with the 6% mix showing the optimal combination of strength and stability. Drill test results verified stronger structures for the samples with added fibers. The assessment indicates that pandan leaves have strong potential to serve as an effective, and even "green," component in the fabrication of long-lasting, exterior-use "fiber-cement" materials
Design of Water Distribution Network through Extended Period Monte Carlo Simulation
No full textThis study presents a comprehensive hydraulic performance assessment of a Level II water distribution system under varying seasonal and operational stress conditions. Using extended period monte carlo simulation, the system was evaluated in terms of pressure, velocity, and headloss behavior to determine its reliability and compliance with design standards. Results show that nodal pressures remained within 16–22 meters, well above the minimum requirement, while optimized velocities (0.47–2.39 m/s) and head losses (0.62-9.48 m/km) consistently fell within acceptable engineering limits. Seasonal demand fluctuations, power outage scenarios, and combined stress conditions were effectively managed through strategic adjustments in pipe sizing, pump operations, and control valve settings. Storage levels in tanks and reservoirs remained stable throughout the 24-hour simulation, ensuring uninterrupted service even during peak demand. The model achieved stable convergence, confirming computational robustness. Conclusively, the findings highlight the system's reliability and provide actionable insights for improved operational efficiency and long-term sustainability. Future work should include field validation, demand forecasting refinement, cost-benefit analysis for recommended interventions across different climatic zones