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The successful implementation of the Clean Air Act has reduced anthropogenic nitrogen oxide (NOx) emissions, significantly reducing acid rain and improving air quality in the U.S. However, particulate nitrate (pNO3) concentrations have remained elevated, posing persistent challenges to link NOx emission sources with pNO3 formation, which limits the ability to evaluate the effectiveness of emission controls for particulate end points. Measured nitrogen isotopes (δ15N) in pNO3 from a 2005-2015 aerosol record in the northeastern U.S. provide direct empirical confirmation of the effectiveness of emission regulations in reducing coal-derived NOx, concurrent with an increasing influence from oil and natural gas combustion. These findings have broad implications for improving our understanding of how changes in NOx emission sources influence pNO3 formation and evaluating the success of past clean air policies.
Heating, ventilation, air conditioning, and refrigeration (HVACR) systems are essential across residential, commercial, and industrial sectors but are critical energy consumers, and their refrigerant emissions and energy use present a major challenge to global sustainability goals. This state-of-the-art review moves beyond tracing the evolution of refrigerants to evaluate key international agreements, including the Kigali Amendment, and national regulations as primary drivers of the transition to sustainable refrigerants. It critically assesses current sustainable alternatives, including natural refrigerants and low-global warming potential synthetic options, such as hydrofluoroolefins, highlighting the trade-offs in their technical application, economic viability, safety, and infrastructure implications. Emerging solutions, including not-in-kind cooling technologies, innovative thermodynamic cycles, advanced materials, artificial intelligence, digitalization, and refrigerant lifecycle management, are examined to provide critical perspectives and guide future research, development, and deployment. By integrating regulatory, market, and technological insights, this review offers a comprehensive road map toward a sustainable, low-emission, and energy-efficient HVACR sector.
Color differences between the sexes (dichromatism) in birds are a hallmark example of a secondary sexual character that is frequently associated with sexual signaling and mate choice. Previous work has shown that the physiological and genetic mechanisms that underlie presence or absence of secondary sexual characters in birds are highly diverse across the avian clade. Hormones such as estrogen and testosterone are known to have important impacts on the development and regulation of plumage coloration across an individual's lifetime, but the distribution of what we know about hormones and dichromatism, relative to the distribution of dichromatic taxa, is confined to a few well-studied taxa. Here, we review current knowledge of hormonal influences on dichromatism and reconstruct the ancestral states of dichromatism across over 8,800 species of birds to highlight where further research is needed. We find that, though two decades have passed since the last major review of hormonal influences on dichromatism, our working knowledge of how hormones influence dichromatism is still functionally and taxonomically limited. Moreover, there is increasing evidence that non-sex hormones such as cortisol and thyroid hormone may have multifarious impacts on dichromatism, including interactive effects on other influential hormones. By combining proximate and ultimate perspectives, we highlight the diversity of hormonal influences on dichromatism in the avian tree of life and put forward ideas for future study.
Nitrogen dioxide (NO2) is mainly discharged from the burning of fossil fuels and remains suspended in the air with other particulate pollutants, which has a significant impact on the Earth's ecological environment and is harmful to human health. Schizophrenia is a nervous system disease involving emotion, thinking, and behavior. There is no consistent conclusion about the etiology of schizophrenia, though numerous studies are ongoing. Previous studies suggest that exposure to NO2 air pollution may increase the risk of schizophrenia, though this remains in the early exploratory stages. We conducted a 2-sample Mendelian Randomization study to investigate the potential causal effect of NO2 exposure on schizophrenia risk. Genetic instruments were selected from large-scale genome-wide association studies of European ancestry, including NO2 exposure (n = 456,380) and schizophrenia (n = 640,808). To ensure the reliability of our findings, we also conducted sensitivity analyses. Across all Mendelian Randomization models, NO2 exposure showed a significant positive causal effect on schizophrenia risk. Beta values ranged from 0.246 (weighted median estimator model, 102 single nucleotide polymorphisms) to 0.478 (inverse variance weighting model, 128 single nucleotide polymorphisms), with all P < .05. odds ratios ranged from 1.30 (95% confidence interval: 1.03-1.65, weighted median estimator, exposure: ukb-b-9942; outcome: ieu-b-5099) to 1.60 (95% confidence interval: 1.39-1.87, inverse variance weighting fixed effects, exposure: ukb-b-5620; outcome: ieu-b-5099). Sensitivity analyses and heterogeneity tests confirmed the robustness of these findings. These findings help further our understanding of the etiology of schizophrenia and provide a new perspective for air pollution mitigation.
Current understanding of the metabolism and adaptation of the commercially important microalga Haematococcus pluvialis in response to stress is limited, in part due to its complex life cycle. Manganese (Mn) is an essential micronutrient but a toxic pollutant when present in excess. This study coupled high-resolution elemental imaging, spectroscopy, and microscopy, alongside metabolic techniques to characterise responses to a high, sub-lethal concentration of Mn in motile microzooids and non-motile palmella cells within the same culture. Some microzooids in response to Mn showed pronounced vacuolisation, loss of cell wall integrity, and significant Mn internalisation within vacuoles, while some cells showed no structural changes and had Mn localisation in the cell wall. Palmella showed less vacuolisation with Mn localised around starch and astaxanthin granules. Microzooids sequestered Mn using intracellular sulphate moieties, probably on sulphated polysaccharides, and carboxyl groups in the cell wall. In response to Mn abundance, microzooids upregulated protein synthesis, depleted lipid energy reserves, with increased membrane fluidity and lipid peroxidation. Palmella also synthesised polysaccharides but otherwise showed no drastic metabolic changes, reflecting higher tolerance to Mn stress. Under normal conditions, microzooids and palmella showed distinctive carbohydrate and protein composition. This knowledge enhances our understanding of the biochemical mechanisms that H. pluvialis uses to manage excess concentrations of this essential micronutrient.
Previous research in cross-country skiing (XCS), frequently emphasises the importance of maximal oxygen uptake (VO2Max) and individual studies have correlated XCS performance with VO2Max. However, meta-regression analyses with multiple studies have not previously been conducted. The aim of this study was to conduct meta-analyses of VO2Max data, in relation to XCS performance using retrospective participant classification framework (PCF) scoring. Electronic databases were searched, up to November 2024, using Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Data were extracted from the included studies (n = 78), with participant groups separated by exercise mode and sex, and retrospectively scored using the PCF. Random effects meta-regressions with sub-grouping were conducted, to calculate pooled mean values by PCF tier, standard error, and 95% confidence intervals. Sufficient data were only present for inferential analysis of running based protocols. VO2Max values generally increased with PCF tier in males and females for both absolute (Male: R2 = 0.80; Female: R2 = 0.66) and relative to total body mass values (Male: R2 = 0.41; Female: R2 = 0.69). Performance prediction is multifaceted, particularly within XCS where numerous physiological parameters are compounded by multiple skiing techniques. These findings emphasise the importance of VO2Max in XCS to develop performance across the participation spectrum. Even within 'elite' athletes, this remains true, possibly reflecting a lack of homogeneity of VO2Max values within this sub-population. The values presented within this study may represent useful benchmark values for talent identification and performance development purposes.
Primary central nervous system (CNS) tumors are rare malignancies with limited treatment options, resulting in high mortality. Unlike other solid tumors, CNS tumors present unique challenges that impact the health-related quality of life (HRQoL) of patients and caregivers. Effective management requires balancing oncologic treatment with the control of neurocognitive deficits, epilepsy, and other neurological symptoms. The European Society for Medical Oncology (ESMO) CNS Faculty conducted a consensus process to identify the most pressing educational priorities for physicians managing CNS malignancies. This process involved structured data collection and expert input to determine critical areas for disease-specific education and training. The consensus process highlighted key educational gaps in managing CNS tumors, emphasizing the need for a multidisciplinary approach to optimize therapeutic strategies, improve survival outcomes, enhance HRQoL during treatment and survivorship, and facilitate access to emerging therapies. Physicians reported that comprehensive, disease-specific education is essential to address these challenges effectively. CNS tumors require targeted educational initiatives to equip healthcare providers with the knowledge and skills necessary for optimal patient care. The ESMO CNS Faculty consensus underscores the importance of structured, disease-specific training to improve outcomes, support HRQoL, and advance oncology education in the management of CNS malignancies.
The poles represent Earth's most climate-sensitive biomes, where microbial communities and viruses drive fundamental ecological processes. Within these extreme environments, giant viruses of the phylum Nucleocytoviricota have emerged as key regulators of microbial mortality and biogeochemical cycling. This review synthesizes current knowledge on polar giant viruses, emphasizing their diversity, endemism, genomic adaptations, and ecological roles across polar habitats. Polar systems harbor highly structured, habitat-specific viral assemblages characterized by significant endemism and sharp ecological boundaries, shaped by strong environmental filtering, host biogeography, virus-virus interactions and spatial isolation. Genomic analyses show that these viruses possess unique adaptations to persistent cold, including proteomic shifts consistent with psychrophily and the enrichment of auxiliary metabolic genes. Interactions with giant virus parasites (virophages) further contribute to the complexity of polar giant virus ecology. However, rapid warming and the loss of perennial ice cover threaten to destabilize these ancient refugia and their giant virus populations. Changes in temperature, hydrological connectivity and ecosystem structure may alter virus-host dynamics and weaken the strong viral endemism. These environmental shifts risk the extinction of unique lineages and the disruption of the critical biogeochemical roles they perform, highlighting the urgent need to understand viral dynamics in rapidly changing polar and cryospheric ecosystems.
Nearly all modern animal phyla emerged 'suddenly' during the early Cambrian Period about 518 million years ago (Ma) in an event known as the Cambrian explosion. Following this evolutionary milestone, the marine invertebrate fossil record is punctuated by five major mass extinction events, collectively called the 'Big Five'. These events include the end-Ordovician, Late Devonian, end-Permian, end-Triassic, and end-Cretaceous mass extinctions (Figure 1). Among them, the end-Permian extinction was the most catastrophic event, resulting in the loss of approximately 81% of marine species within a short geological interval. In this primer, I will discuss the potential reasons why the End-Permian extinction event had such a profound effect on terrestrial plant life. I will draw examples from the best preserved ecosystem from this time period - the Cathaysian Flora.
Glaciers are recognized as secondary sources of per- and polyfluoroalkyl substances (PFAS) in a warming climate. Yet, the process governing the release of legacy PFAS from glaciers and the occurrence of their emerging homologues in the meltwater remain insufficiently characterized. Here, we measured glacial meltwater from Mt. Everest at elevations of 4,400-5,300 m using a combination of target quantification, the total oxidizable precursor (TOP) assay, and nontarget analysis. Short-chain PFAS, particularly perfluorobutanoic acid (PFBA), dominated at all sites, accounting for over 88% of the total PFAS concentrations. Furthermore, hydrological processes, rather than solar radiation, drive the release of PFAS from glaciers. A modest (∼25%) increase in concentration after the TOP assay suggests a limited pool of oxidizable PFAS precursors in the meltwater. Follow-up nontarget analysis identified four hydrogen-substituted perfluoroalkyl carboxylic acids (H-PFCAs; C5, C7, C8, and C9) and three hydrogen-substituted perfluoroalkanesulfonates (H-PFSAs; C6, C7, and C8). To our knowledge, this is the first study to report the presence of emerging hydrogen-substituted PFAS in glacial meltwater. These findings expand the known suite of PFAS in the cryosphere and underscore the need for optimized analytical strategies to detect trace-level emerging PFAS in high-altitude environments.
Excessive environmental heat exposure is clearly associated with an increased likelihood that individual patients will suffer adverse health outcomes. Such heat exposure also strains healthcare systems via increased utilization, a burden which can challenge systems' capacities. Health impacts vary geographically with urban heat islands potentially contributing to higher temperatures and greater health risks. However, those most vulnerable to this exposure are not well identified. Our objective in this novel study was to compare and quantify differences in emergency medical services (EMS) use by selected patients during hot days in Rhode Island. Patients were recruited from low socioeconomic residential locations, stratified by whether they accessed EMS from within one of the state's "urban heat islands," or from other locations without "heat island" effects. We also compared selected patient demographic characteristics, and other EMS run data, between events associated with EMS access from these two types of areas. This retrospective, cross-sectional cohort study evaluated how the probability of an EMS encounter varied in response to daily mean temperature and the urban heat island status of the encounter location. We aggregated EMS dispatch data, daily mean temperature, urban heat island classification and the Area Deprivation Index of the encounter location. A quasi-Poisson regression model assessed the relationship between EMS encounter frequency and potential risk factors including daily temperature, urban heat island status, year, day of the week, sex, age, and relevant interaction terms. The model was restricted to low socioeconomic, residential encounter locations to reduce confounding (noted elsewhere by year) and focus on the target population. The primary outcome was the rate ratio (RR) of EMS encounters for urban heat island locations vs locations without an urban heat island effect, in response to summer temperatures. Secondary outcomes included RRs of EMS encounters stratified by age, sex, weekday vs weekend, and year. Higher temperatures were associated with increased EMS call rates across all demographic subgroups. A 5 °F (2.8 °C) increase in mean daily temperature was associated with an increase in an overall EMS encounter rate of 1.5% (RR, 1.015; 95% CI, 1.005-1.031, P = .004). On a weekday in 2021, at 75 °F degrees, 68 EMS encounters would be predicted for the residential, low socioeconomic status locations in the state while at 95 °F, 73 EMS encounters would be expected. The EMS rates were consistently higher in urban heat islands across all study years, after accounting for daily temperature, year, day of the week, demographic characteristics, population size and interactions between age, sex, urban heat island and weekday vs weekend. The largest relative increase in EMS encounters was observed in 2019, with rates 34% higher in urban heat islands compared to locations without an urban heat island effect (RR, 1.34; 95% CI, 1.27-1.42). The smallest increase occurred in 2020 (RR, 1.12; 95% CI, 1.06-1.18). In residential and low socioeconomic locations, living in an urban heat island increased the probability of an EMS encounter, highlighting potential compounding effects of social and environmental vulnerability. As climate change intensifies extreme heat events, locationally targeted interventions may be critical in reducing heat-related health impacts.
Chlorine (Cl) is a critical halogen and acidic component that influences atmospheric oxidation capacity, air quality, and acidifies ecosystems. Emission reduction measures in China are expected to similarly reduce Cl deposition as with sulfur (S). However, large knowledge gaps remain regarding the trends and drivers of China's Cl deposition. By integrating data from an observational network and published literature, we developed the first national dataset of Cl wet deposition in China from 1990 to 2020. This dataset revealed that total Cl- and nonsea-salt (NSS) Cl- deposition initially increased, reaching an inflection point around 2005, and then decreased, with an overall reduction of approximately 52%. As anticipated, Cl and S deposition decreased synchronously nationwide, attributable to reduced precursor emissions from energy structure adjustments and emission reduction technologies. However, in China's three major urban agglomerations, Cl did not decrease in parallel with S and even increased in the Pearl River Delta at a rate of +8% yr-1. This mainly stems from rising waste incineration emissions driven by rapid economic and urban development, population and consumption expansion, which offset the mitigation achieved from coal combustion. Our study underscores the effectiveness of emission reduction measures, yet targeted control of emerging anthropogenic Cl pollution sources in urban hotspot areas is urgently needed to achieve regional sustainable development.
The rapid integration of generative artificial intelligence (AI) tools into higher education has intensified conversations regarding usefulness, ethical alignment, and responsible engagement. Unlike traditional technology acceptance studies that focus on initial use, this study examines AI use intensity among active university users. Building on an extended Technology Acceptance Model (TAM), the model incorporates AI-Alignment Construct, reliance-based trust in AI outputs, and normative alignment within academic contexts. Data were collected from 637 university students and analyzed using variance-based structural equation modeling. The results indicate that perceived usefulness remains the strongest predictor of AI use. Furthermore, reliance-based trust and AI-Alignment Construct demonstrate statistically significant correlations with engagement, whereas moderation hypotheses were not supported. These findings suggest that ethical and trust-related mechanisms operate primarily at the attitudinal alignment level rather than as boundary conditions within this cross-sectional framework. Moreover, the study contributes by repositioning TAM within a post-adoption engagement context and clarifying the bounded conceptualization of ethics and trust in AI-mediated learning environments. Practical implications emphasize calibrated AI integration, transparent governance, and assessment design aligned with academic integrity. Finally, the findings are associative in nature and should be interpreted within the methodological constraints of self-reported, cross-sectional data.
Although it seems impossible to make reliable predictions about climate changes in the near future, an attempt will be made to answer the question posed in the title of this contribution. To this end, a few basic concepts which influence the climate on Earth will be discussed. The principal difficulty is the fact that in the long history of the Earth it is the first time that natural variations of the climate are influenced by human activities as well. And here, the problem arises that besides scientific issues of how these activities (e.g. fossil fuel burning) influence the climate, economic and political considerations are also drawn into the discussion. And this clearly has consequences on how to react to some of the observed changes (e.g. global warming). But emerging technologies to trace radionuclides in the environment at large may still help to get a better understanding of the climate on Earth.
High-entropy MXene derivatives offer new opportunities for electromagnetic wave absorption materials by introducing structural and electronic complexity, whereas the construction of robust multisource built-in electric fields (BIEF) to enhance electromagnetic attenuation remains a significant challenge. Herein, we designed high-entropy MXene-derived multicomponent nitrides for efficient electromagnetic absorption via sequential oxidation and nitridation of the TiVCrMoC3Tx precursor. The high-entropy-driven phase transformation induces complex phases and microstructures involving multiple metallic nitrides and narrow-gap semiconducting nitrides with abundant heterogeneous interfaces and structural defects. Combined electron holography and theoretical calculation reveal the presence of multisource BIEF derived from abundant short-range dipoles, stable long-range dipoles, and work-function-driven interfacial charge redistribution. Various dipoles construct robust BIEF networks with stable polarization oscillations and a rapid dielectric response over a broad frequency range. Benefiting from the synergistically enhanced dipole polarization, conduction loss, and optimized impedance matching, the ON-TiVCrMoC3Tx achieved a minimum reflection loss of -52.02 dB and an effective absorption bandwidth of 4.8 GHz at a thickness of only 2.0 mm. This work not only sheds light on the origin and regulation of BIEF for enhanced electromagnetic absorption but also provides an effective strategy to construct multisource BIEF for the design of electronic, optoelectronic, and sensing devices.
Uranium (U) and rare earth elements (REEs) are both strategic metallic elements. With the consumption of high-grade mineral resources, it is necessary to enhance the utilization of complex low-grade resources. This study proposes an ultrasonic-enhanced alkali pretreatment - acid leaching process for the recycling of uranium tailings associated with REEs. The ultrasonic-assisted alkaline pretreatment effectively disrupted the gangue structure by dissolving a portion of silicon (3.66%) and aluminum (5.59%). This enhanced the accessibility of metals encapsulated within the gangue minerals and altered the speciation of residual REEs, thereby facilitating the subsequent acid leaching of both U and REEs. The advantageous regions for acid leaching of U and REEs were identified through thermodynamic analysis. Effects of ultrasonic-assisted acid leaching conditions on the leaching efficiencies of U and REEs were investigated. The optimized acid leaching conditions are as follows: HCl concentration of 2.5 mol/L, leaching temperature of 70 °C, leaching time of 2 h, L/S ratio of 10:1, H2O2 addition of 5%, and ultrasonic power of 400 W with frequency of 40 kHz. The leaching efficiencies of U and REEs reached 90.43% and 72%, which increased by 17.09% and 12.33% respectively, compared to conventional leaching. The characteristics of the residue before and after ultrasonic leaching were compared to analyze the leaching mechanism. During acid leaching, the free radical capture experiment found that the ultrasonic effect promoted the decomposition of hydrogen peroxide to produce more free radicals, oxidizing insoluble U(IV) to dissolved U(VI). The ultrasonic effects strengthened the leaching kinetics for both U and REEs. The results provide an enhanced method for the efficient utilization of low-grade encapsulated mineral resources.
In this Letter, we introduce a scalable and physics-informed (PI) computational implementation for determinant-based multireference (MR) calculations. The PI philosophy is deeply embedded throughout the methodology and its implementation. At the method level, the orbital entanglement is used to guide an optimized reconstruction of selected CI wave functions, while the MR stage employs a PI kernel optimization (PIKO) strategy that explicitly accounts for configuration grouping patterns and memory access irregularities of integrals. In system hardware codesign, the PI parallel optimization (PIPO) strategy is proposed, with which the most computationally intensive MR module is accelerated via an entropy-based performance model and a hierarchical load-balancing scheme; both of them exploit physical insights into workload irregularity and data locality. This consistent PI-driven approach enables remarkable heterogeneous computing efficiency and parallel scalability. Single-GPU accelerations reach ∼460 times those of full CPU cores, and the strong scaling efficiency exceeds 92.5% on up to 4000 GPUs using HPC clusters. Furthermore, scalar relativistic effects can be incorporated consistently, and spin-orbit coupling (SOC) effects can be included through the present SO treatment.
Lake Kralingse Plas (Rotterdam, the Netherlands), with a surface area of 114 ha and an average depth of 2.3 m, regularly suffered from cyanobacterial blooms. To improve water quality and meet the requirements of the European Union Water Framework Directive (WFD), the responsible authorities, following a system analysis, applied 1064 tonnes of lanthanum-modified bentonite (LMB, commercial name Phoslock®) to the entire lake in November 2021. Water quality was monitored by the water authorities on a monthly basis. Just before the LMB application, at 3, 15, and 36 months post-LMB application, sediment phosphorus (P) release, sediment P fractionation and Lanthanum (La) fate in the sediment were estimated. Following the application, the sediment La content was significantly higher in the top 4 cm of the sediment layers compared to pre-application conditions. The "HCl-P" pool was increased after LMB application, reflecting LaPO4 formation. It was the highest P fraction, increasing from 53.7% at pre-application to 59.5% after 3 months, further increasing to 62.6% of total P after 15 months, and 66.7% after 36 months. This suggested that LMB reduced sediment P release by increasing the non-bioavailable P in the sediment. The average filterable P (FP) fluxes in the sediment cores under anoxic conditions were 6.27 (±4.4), 0.29 (±0.21), -4.65 (±3.1) and 0.27 (±0.42) mg P m-2 day-1 in cores taken before the application, 3, 15, and 36 months after the application, respectively. In addition, to address the LMB efficacy on P release at different pH levels (pH 7 and pH 10), a 256-day sediment core incubation was conducted. The release rate of P following LMB application did not differ between pH 7 and pH 10, indicating the stability of La-bound P under alkaline conditions. This finding is particularly relevant for shallow eutrophic lakes, where high pH and internal P loading may occur.
Phase relationships in the MgO-Al2O3-Cr2O3 system have been studied experimentally at pressures of 12, 14, 18 and 22 GPa and a temperature 1600 °C. The first set of experimental runs returned several phases with varying proportions of MgAl2O4 and MgCr2O4 end-members. In the second series, two phases with stoichiometrical formulae MgCr1.43Al0.57O4 and Mg1.93Al1.22Cr0.79O5 calculated, simplified as Mg(Cr,Al)2O4 and Mg2(Al,Cr)2O5, respectively, were obtained. The first phase has a calcium titanate-type structure, orthorhombic unit cell (a = 2.8328 (Litasov et al., 2004 (4)) Å, b = 9.3956 (Bindi et al., 2014 (15)) Å, c = 9.5898 (Bindi et al., 2014 (15)) Å, V = 255.2407 (Akaogi, 2007 (5)) Å3, Z = 4) and the space group Cmcm. The second phase is orthorhombic as well, has a modified ludwigite-type structure with unit cell parameters a = 12.3490 (Sirotkina et al., 2018 (18)) Å, b = 9.4937 (Wang et al., 2002 (13)) Å, c = 2.8299(4) Å, V = 331,77 (Ricolleau et al., 2010 (7)) Å3, Z = 4 and a space group Pbam. Pressure-induced changes of the new post-spinel phases Mg(Cr,Al)2O4 and Mg2(Al,Cr)2O5 have been examined by in situ Raman spectroscopy at pressures up to 30 GPa. At 12-16 GPa the crystal color changes from green to red, which persists with further pressure increase. The studied phases are stable at lower mantle conditions, can be considered as post-spinel phases and may accommodate crustal elements in the deep interiors of the Earth.