Abstract The frequency and severity of summertime synchronous extreme heat waves across the Northern Hemisphere are increasing with global warming, threatening ecosystems, economies, and human health. Understanding the spatiotemporal characteristics of these heat waves is therefore crucial. This study employs the event synchronization climate network method to objectively identify hotspot regions of synchronous extreme heat waves and their dominant synchronization patterns. It further explores the associated large-scale atmospheric circulation patterns and soil moisture feedback processes. Results show that regions including most of Europe, the western Arabian Peninsula, East Asia, Southeast Asia, and the western and southern parts of North America, as well as Greenland, are susceptible to synchronous heat waves. Notably, Southeast Asia and western North America show strong synchronization with the Caspian Sea, while East Asia and southern North America primarily synchronize with northern–central Europe. Southeast Asia–Caspian Sea and East Asia–northern–central Europe synchronization patterns are linked to wave-like anomalies suggestive of northwest–southeastward-propagating Rossby waves, whereas western North America–Caspian Sea and southern North America–central Europe synchronization patterns correspond to zonal wave trains. These circulation patterns feature concurrent anticyclonic anomalies over synchronized heat wave regions, favoring warming through adiabatic subsidence and increased solar radiation. Moreover, concurrent local soil moisture drying increases the likelihood of their co-occurrences by positive land–atmosphere feedback, which likely acts to intensify and prolong heat waves. These findings systematically map synchronous heat wave hotspots and synchronization patterns across the Northern Hemisphere, highlighting novel cross-latitudinal connections and establishing a foundation for future work to disentangle dynamic and thermodynamic influences. Significance Statement As global temperatures rise, extreme heat waves are becoming more frequent and severe, especially in the Northern Hemisphere. This study reveals that heat waves are increasingly occurring simultaneously across distant regions, such as Europe, North America, and Asia. These synchronous heat waves pose serious risks to ecosystems, agriculture, economies, and human health. By using a novel climate network analysis, this study identifies regions most vulnerable to these synchronous heat wave events and the pathways through which they are linked. Understanding these patterns is crucial for predicting future heat waves, improving climate models, and helping societies to better prepare for the widespread impacts of extreme heat as the planet continues to warm.

Abstract We perform a global assessment of dryness and wetness conditions using an ensemble of observational, satellite-informed, and reanalysis-based soil moisture datasets [soil moisture (SM) Global Land Evaporation Amsterdam Model (SM GLEAM ), SM ERA5-LAND , and SM MERRA-2 ] and drought indices [Palmer drought severity index (PDSI CRU ) and standardized precipitation evapotranspiration index (SPEI CRU )]. Over the short term (1982–2023), four or more products consistently identify drying trends in western North America, South America, the Mediterranean, Europe, central Asia, and southern Australia. Wetting trends appear in southern and southeastern Asia, the Sahel, and parts of southern sub-Saharan Africa, while disagreements across products are most evident in central Africa, parts of South America, the Middle East, and Southeast Asia. The year 2023 ranks among the driest on record since 1982: driest in PDSI CRU and SM ERA5-LAND , second driest in SM GLEAM and SPEI CRU , and eighth in SM MERRA-2 . A longer-term analysis using PDSI CRU from 1903 to 2023 estimates that 2023 was the most severe and spatially extensive drought year in over a century, affecting more than 27% of the global reporting land area. Moreover, the 2021–23 period marks the longest consecutive stretch of extreme drought conditions globally since the early twentieth century. The global patterns of droughts over 2021–23 align with long-term drying trends, consistent with the broader influence of anthropogenic climate change on global hydroclimate. Despite the presence of long-term wetting trends, the wetness of the past decades has not produced events of comparable magnitude to those in the mid-twentieth century, a time that remains unmatched in both the severity and extent of wet extremes. Significance Statement On a global scale, the years 2021–23 have seen some of the most widespread and severe drought conditions in over a century. By analyzing five major datasets that characterize changes in soil moisture conditions, we find that 2023 was the driest year on record in over 120 years and that 2021–23 was the driest 3-yr period over the same time interval. We show that these recent twenty-first-century extremes are consistent with long-term drying trends and highlight a broad intensification of hydroclimate extremes across much of the globe. While previous work has emphasized regional drought events over shorter intervals, this study uses multiple datasets in a global framework to provide strong evidence that anthropogenic climate change is a key driver of an intensifying global pattern of more widespread and severe drought.

Associations between classroom ventilation rates and school characteristics with indoor air in classrooms during wildfire smoke events.

Abstract In this study, we explore the role of upstream processes associated with the western North American heat wave of late June 2021. Upstream latent heat release associated with an atmospheric river (AR) contributed substantially to both upper- and lower-tropospheric features of this event, including a contribution from an unusual chinook/foehn mechanism. A subset of lower-tropospheric back trajectories from the heat wave region exhibited latent warming during ascent associated with an AR over the Gulf of Alaska and also over mountainous coastal regions of southeast Alaska. Thermodynamic analysis of air trajectories demonstrates that latent heat release in the AR and with orographic lift contributed to the extreme lower-tropospheric warmth in the Pacific Northwest and British Columbia. Numerical experiments with reduced relative humidity over the Gulf of Alaska weaken the upstream AR and demonstrate a strong connection between the upstream latent heating, upper-tropospheric ridging, and exceptionally hot boundary layer temperatures in the U.S. states of Washington and Oregon and the Canadian province of British Columbia. Objectively sorted trajectories reveal distinct warming processes, including adiabatic descent, upstream condensational heating, and radiational warming in the planetary boundary layer. Trajectories originating in the lower troposphere in an experimental simulation in which the upstream atmospheric river was weakened are associated with cooler near-surface temperatures in the heat wave region. We propose that for some warm-season heat waves, upstream condensational warming contributes substantially to lower-tropospheric heat. Significance Statement In late June 2021, a record-setting heat wave affected parts of western North America. Where did the hot air originate, and what processes heated it? Here, we explore the processes that generated the extreme near-surface warmth using air trajectories (calculated flow pathways) and numerical model experiments. Our analysis shows that heat released by condensation over the Gulf of Alaska and mountainous coastal Alaska associated with a preceding atmospheric river contributed to the heat, though this was one of several processes driving the heat wave.

ABSTRACT Global environmental change during the Cenomanian–Turonian interval caused the widespread deposition of organic-rich mudstones in marine basins. In the southern part of the Western Interior Seaway and the northeastern portion of the Mexican Interior Basin, these rocks are represented by the Eagle Ford unit. A multi-proxy approach was applied to two drill cores of this formation in northeastern Mexico to provide insights into its depositional and environmental history and hydrocarbon source-rock potential. The uppermost part of the underlying Buda Formation was deposited in a carbonate-dominated outer shelf to slope environment characterized by the settling of planktonic organisms from mesotrophic to eutrophic surface waters onto a well-oxygenated seafloor. The organic-rich mudstone of the lower Eagle Ford member began to be deposited between the final part of early Cenomanian and the middle Cenomanian in a slope to open-marine setting with high terrigenous input, and mostly under eutrophic surface and anoxic bottom water conditions. This unit was formed by the settling of fine-grained particles and subsequent reworking by bottom currents. Possible turbidites, as well as soft-sediment deformation caused by density inversion, and synsedimentary faulting associated with down-slope gravity movements, affected the sedimentary record. The bioturbated limestone of the upper Eagle Ford member was deposited in a shallower environment under oxic conditions. Bottom currents were stronger and more active during deposition of the upper part of the Eagle Ford Formation and its transition to the overlying Austin Formation. Bentonite in the Eagle Ford Formation resulted from the alteration of volcanic ash of intermediate composition derived from the Cretaceous Cordilleran arc of western North America. Vertical changes in the gamma-ray trends throughout the studied units correlate with those documented in Texas. The organic matter of the Eagle Ford Formation in the northern part of the Sabinas Basin is typically in the post-mature state.

Advanced sequencing technologies and improvements in bioinformatics have provided a new way to study plant-associated microbial communities, including the use of host genomic sequencing. Our study focuses on the leaf microbiome of basin big sagebrush (Artemisia tridentata subsp. tridentata), a foundational shrub of western North America. We analyzed Illumina shotgun sequences from sagebrush leaves to investigate the metagenomes of leaf-associated microbes that were sequenced alongside their plant hosts. We aimed to profile the leaf microbiome across different sample sources (magenta box, greenhouse, and field/wild), reconstruct metagenome-assembled genomes (MAGs) where possible, and investigate functional gene annotations of the resulting MAGs, specifically with regard to the potential metabolism of sagebrush chemicals. To achieve this, Illumina shotgun sequence reads (containing both host and associated microbial reads) were mapped to the reference genomes of Artemisia tridentata, Artemisia annua, and the human reference genome to remove plant host and human-associated sequences. Host-cleaned reads were then analyzed using microbial metagenomics techniques. Taxonomic profiling revealed that Phyllobacterium and Sphingomonas were the most abundant microbial genera in greenhouse-grown plants, with very little variation among the samples. Wild, field-collected samples were much more variable and were dominated by Klebsiella and Aureobasidium species. From the co-assembly of greenhouse samples, we reconstructed two high-quality MAGs (a Phyllobacterium species and a Sphingomonas species) with >98% completion and <1% contamination. Functional annotation of these MAGs uncovered genes associated with the degradation and metabolism of camphor and other essential oils such as pinene, geraniol, and limonene, which are part of sagebrush leaf chemistry.IMPORTANCEBig sagebrush (Artemisia tridentata), the foundation species of the sagebrush steppe, has broad ecological importance because its evergreen leaves offer nutrients and shade that facilitate the establishment of diverse understory plants in arid environments. Sagebrush leaves contain various secondary metabolites, including terpenoids, flavonoids, and phenolic compounds. These chemicals contribute to the plant's defense mechanisms against herbivores and pathogens. Despite this, sagebrush hosts diverse bacterial and fungal communities. We found that the microbial metagenome-assembled genomes (MAGs) we recovered contained genes that have the potential to degrade some of the chemical compounds in sagebrush leaves that could inhibit the growth of other microbes. This is the first study to mine plant genome data using host-derived sequences to generate microbial MAGs. Our results showed that MAGs can be recovered from plant host-derived sequence data, providing a new way to explore the identity and functional capabilities of difficult-to-culture microbes.

Climate change forces species to adapt rapidly to avoid extinction. To directly observe rapid adaptation and extinction, we conducted synchronized evolution experiments with Arabidopsis thaliana in 30 locations across Western Europe, the Mediterranean, the Levant, and North America. Whole-genome pooled sequencing of ~70,000 surviving plants revealed repeatable allele frequency shifts in similar climates but divergent shifts across contrasting ones, indicating evolutionary adaptation. We identified genetic variants linked to climate adaptation, including genes involved in processes ranging from thermal-stress sensing to spring-flowering timing. Evolutionary trends were often predictable, but variable, across environments. In warmer climates, evolutionary predictability correlated with population survival over 5 years, whereas erratic changes preceded extinction. These results show that rapid climate adaptation is possible, but understanding its limits will be crucial for biodiversity forecasting.

A goal of applied ecology is to evaluate how demographic rates contribute to population growth and how demography might be manipulated to achieve management objectives. In western North America, many feral horse ( Equus caballus ) populations occupying public lands are protected by federal law and managed for site-specific numerical targets. However, feral horses can exhibit population growth rates exceeding 20% per yr, which can lead to overpopulation, and therefore conflict with other permitted land uses. In response, some stakeholder groups have advocated for natural solutions to the problem of rapid growth and overabundance. Mountain lion ( Puma concolor ) predation has been hypothesized to have suppressive effects on horse population growth rates under some conditions. Here, we evaluated the degree to which this phenomenon might reduce feral horse growth rates using elasticity analysis, scenario analysis with simulations, and an empirical state-space model for a horse population in southeastern Nevada subject to chronic predation. Age-specific elasticities revealed that annual population growth rates (λ) were more sensitive to perturbations in foal and yearling survival rates than for older age-classes. This finding, in conjunction with empirical measures indicating that foals comprised approximately 60% of horses killed by mountain lions, suggests that predation may have greater potential to reduce horse population growth rates than previously recognized. Scenario analysis predicted that horse populations could decrease to target levels within 10 years if predation reduced: (1) annual foal survival by 80% each year, or (2) annual survival rates of foals, yearlings, and 2-year olds by &amp;gt;60%. The state-space model indicated that the heavily predated Nevada horse population experienced positive population growth during 2022 and 2023 (λ = 1.07, both years). Using information on known predation-caused mortalities from 2020–2021, our model predicted that population growth rate in the absence of predation (‘predicted λ’) would have been approximately twice as high (predicted λ 2020 = 1.14; predicted λ 2021 = 1.14 in 2021). Taken together, our results suggest that predation is unlikely to singularly induce stable or negative population growth of feral horses. That said, our findings suggest two aspects of predation that may benefit resource managers. First, chronic predation may reduce λ, thereby increasing the time required for populations to either recover from declines, or exceed management objectives; and second, predation may be most effective in achieving management objectives for horse populations when combined with other interventions, such as removals or fertility control treatments.

The replacement of the atlatl and dart by the bow and arrow marks a major technological transformation in the human past, yet the timing and dynamics of this transition in North America remain poorly resolved due to the poor preservation of organic weaponry. Here, we compile and analyze a dataset of 140 radiocarbon dates from 136 well-preserved organic weapons recovered from western North America, spanning approximately the last 10,000 years. Using chronological modeling, optimal linear estimation, and Bayesian logistic regression, we show that bow technology first appears in both northern and southern regions around 1,400 years before present. The dynamics of adoption, however, differ sharply by region. In the south, across a vast area from northern Mexico to California and the Southwest, the bow rapidly and almost completely replaces the atlatl, a case of technological disruption in which an innovation decisively renders an older system obsolete. In the north, in contrast, the bow and atlatl coexisted for more than a millennium. This coexistence reflects a broader global pattern of increasing technological richness at higher latitudes, where ecological risk is mitigated through diversification rather than specialization. Our findings clarify previous claims of much earlier bow use in North America, demonstrate the importance of rare invention events followed by rapid diffusion, and highlight the contingent pathways by which technologies are adopted or abandoned. These results provide insight into the processes of technological evolution, showing how innovation, ecology, and cultural transmission interact to shape long-term human history.

Cryphalus dilutus is an emerging invasive pest of tropical and subtropical regions, with Mangifera indica and Ficus carica being its primary host plants. Larval damage caused by this insect can lead to severe tree wilting, posing a direct threat to agricultural production and ecological security. Native to South Asia, C. dilutus has established introduced populations in the Near East, Mexico, and other areas. In recent years, it has invaded multiple regions, including southern China and southern Italy. Given the widespread global distribution of host plants and the intensification of climate change, their distribution ranges are expected to expand. However, research assessing the potential global geographical distribution of this pest under climate change is lacking. In this study, we used the Random Forest model to predict the potential distribution range of C. dilutus. Under historical climatic conditions between 1970 and 2000, suitable climatic regions for C. dilutus were primarily distributed across southern China, southeastern Brazil, southeastern Mexico, the Congo Basin periphery, and the Iberian Peninsula, with a total area of 12,192.42 × 104 km2. The Temperature Annual Range and Precipitation of Warmest Quarter were identified as key environmental determinants that shaped its distribution. Under the future RCP4.5 climate scenario projected for the 2050s, the total suitable area for C. dilutus is projected to contract. Specifically, high-, medium-, and low-suitability areas are projected to decline by 52.77%, 62.39%, and 24.02%, respectively. While the total area of the very low zones is expected to increase, the total area of the suitable region has been reduced to 11,891.17 ×104 km2. Future climate change is expected to drive the distribution northward to high-altitude areas and inland areas. Model projections indicate a poleward expansion of the fundamental climatic niche, with climatic suitability increasing in high-latitude and high-altitude regions, such as Northern Europe and western North America. Conversely, current core tropical habitats in the Indian subcontinent and the Amazon Basin are projected to face significant habitat degradation due to thermal stress. Agricultural regions previously considered relatively safe due to climatic constraints, such as northern China, the midwestern United States, and Eastern Europe, may face new challenges from pest infestation. These findings underscore the importance of proactive monitoring and implementation of preventive measures. This provides crucial decision support for countries and regions to formulate precise pest control strategies and offers a theoretical basis for early monitoring and prevention of cross-border invasions on a global scale.

Edible baits for systemic flea control, plague mitigation, and wildlife conservation: evaluation of four active ingredients with three rodent species in western North America

Abstract Heat extremes occurring synchronously in multiple regions often result in more severe impacts than isolated heat events. Here we analyze observational and reanalysis data to objectively detect and examine the synchronization of heat extremes in the Northern Hemisphere and identify the regions that have remote linkages, particularly in western Europe (WEU), western North America (WNA) and the Yangtze‐Huai River Basin (YHRB). The results indicate that the intensity and frequency of synchronized heat extremes show increasing trends during 1979–2023 summer, with most events occurring in the past 20 years. The synchronized heat extremes are triggered by a quasi‐stationary Rossby wave with wavenumber 6, resembling a circum‐global teleconnection (CGT)‐like pattern along the subtropical jet. While large‐scale atmospheric circulation provides a common dynamical background, the sustaining mechanisms differ across regions. Land‐atmosphere interactions and surface processes jointly reinforce the persistence of synchronized heat extremes, providing new insights on compound event analysis.

Abstract Invasive zebra ( Dreissena polymorpha ) and quagga ( Dreissena rostiformis bugensis ) mussels (ZQM) are spreading across western North America, but are not yet known to be established in Alaska. If they invaded Alaska, ZQM could disrupt freshwater ecosystems supporting some of the world’s most productive wild salmon fisheries. This study examined a key factor limiting ZQM invasion risk, the concentration of dissolved ionic calcium (Ca 2+ ), by synthesizing existing water quality data from published and unpublished sources and collecting new samples to fill data gaps for important salmon-bearing lakes across Alaska. We assembled a geospatial dataset including observed dissolved Ca 2+ concentrations for 1406 lakes and used a randomForest model to predict Ca 2+ concentrations for 1182 additional lakes using other water quality parameters as predictors. The most important predictors of Ca 2+ were Mg, conductivity, pH, Si, Na, and K. Both predicted and observed Ca 2+ values were highly variable, ranging from 0.1 to 35.8 mg/l. A total of 888 lakes had moderate or high risk for ZQM (Ca 2+ values &gt; 12.0 mg/l), including many important salmon-bearing lakes, and 1700 lakes had minimal (Ca 2+ values of 0.0–8.0 mg/l) or low (Ca 2+ values of 8.1–12.0 mg/l) suitability. No region of the state had consistently low suitability for ZQM based on calcium levels, meaning prevention efforts will need to focus at the scale of individual lakes rather than assuming that entire regions are safe from invasion. This study assists in prioritizing prevention, education, and early detection and rapid response to focus on lakes with the greatest potential for ZQM invasion of highly valued ecosystems and fisheries.

Waxing and waning of continental ice sheets on Gondwana during the late Paleozoic ice age induced high-magnitude eustatic sea-level fluctuations that have long been attributed to orbitally driven insolation variation and are recorded in mid-Mississippian through Early Permian cyclic marine strata worldwide. These strata are particularly prominent in western North America, where a series of basins contain thick deposits of paleoequatorial seas. To better understand orbital forcing, glacial-interglacial cycles, and the expression of shelf and slope lithofacies across a deep- to shallow-marine stratigraphic transect, we measured stratigraphic sections of conodont-bearing upper Pennsylvanian through lower Permian strata along the western Laurentian margin, sampled carbonate for stable isotope analysis, and collected handheld gamma ray logs of the Keeler Canyon Formation at Ubehebe Mine and Cerro Gordo, California, and the coeval Bird Spring Formation at Arrow Canyon, Nevada, USA. The Keeler Canyon Formation is a 1-km-thick succession of intercalated gravity flow deposits, turbidites, and marlstones and was deposited coeval with the Bird Spring Formation, which consists predominantly of shallow-marine carbonates. Cyclicity at Ubehebe Mine and Cerro Gordo is a prominent facies alternation between intervals of debrites and turbidites with high carbonate δ13C values (−4.12‰ to 2.80‰; 0.92‰ average, from the Cerro Gordo section) and intervals of organic-rich silty marlstones with low δ13C values (−5.68‰ to 3.73‰; 0.05‰ average, from the Cerro Gordo section). Coeval strata at Arrow Canyon consist of shallower marine carbonate lithofacies with less prominent variation in lithofacies and generally high (−1.10‰ to 5.02‰; 3.42‰ average) carbonate δ13C values. During the Pleistocene icehouse, low- and high-δ13C marine carbonates accumulated during interglacial highstands and glacial lowstands, respectively, with 13C enrichment attributed to glacially enhanced thermohaline circulation and resultant productivity and accumulation of 12C as organic matter in marine sediments. Using the Pleistocene icehouse as analog, coarse-grained turbidite and debrite intervals of the Keeler Canyon Formation represent increased shelf instability and gravity-flow transport to the deep sea due to lowered sea level during glaciations, and intervening organic-rich marlstone intervals represent interglacial periods when the shelf was inundated and deposition was focused up-dip. Asselian Stage strata yield the highest δ13C values in the Keeler−Bird Spring record, consistent with the global Asselian record of significant glaciation and associated low sea level. To better understand the dynamics of lithofacies cyclicity and their relationship with orbital forcing, we constructed a high-resolution time scale and analyzed gamma ray−measured elemental K, U, and Th concentrations and δ13C time-series constrained by U-Pb-dated conodont zones using the “Astrochron” R package. Evolutive harmonic analysis reveals prominent bundled periodicities that closely match predicted late Paleozoic orbital cycles and the existing record of late Paleozoic orbital cycles. The 405 k.y., 123 k.y., and 95 k.y. eccentricity cycles were identified at all locations, and obliquity and precession are apparent in densely sampled portions of the Keeler Canyon Formation. The results indicate that long- and short-eccentricity cycles are discernable across both shelf and deep sea deposits of equivalent age, and likely controlled the timing of sea-level fluctuations and deposition of debrites and coarse-grained turbidites in the Keeler Canyon Formation, which have average recurrence intervals of 404 k.y. and 102 k.y., respectively, suggesting that deposition of these lithofacies was paced by the long- and short-eccentricity cycles. Enhanced deposition of these lithofacies during sea-level lowstand was likely paced by minima in the eccentricity cycles, which are thought to reduce seasonal contrast and summer ice melting, leading to greater ice sheet accumulation and glacioeustatic sea-level lowering.

BackgroundSimulation has emerged as a transformative method in surgical education, offering reproducible training in risk-free environments. While widely adopted in Western Europe and North America, traditional apprenticeship remains dominant in Central and Eastern Europe, raising concerns about skill acquisition and standardization.ObjectiveThis study compared obstetrics and gynecology residents’ perceptions of simulation-based versus apprenticeship laparoscopy training in Poland, focusing on expectations, skills acquisition, instructor engagement, and training structure.MethodsA cross-sectional survey was conducted among 59 residents: 29 completed structured VR simulation-based courses and 30 participated in operating room apprenticeship. Data were collected using two course-specific questionnaires, from which nine comparable parameters were extracted. Chi-square tests were applied where distributions allowed; other items were analyzed descriptively.ResultsSimulation participants reported significantly greater fulfillment of expectations (96.6% large/very large vs 6.7% apprenticeship; χ2=48.35, p<0.05) and higher skill acquisition (86.2% high/very high vs 10% apprenticeship; χ2=40.60, p<0.05). Training duration and repetitions were more often judged optimal in the simulation group (82.8% and 93.1%, respectively) than in the apprenticeship group (33.3% and 10%). Instructor engagement was markedly higher in simulation (96.6% high/very high vs 3.3% apprenticeship; χ2=52.24, p<0.05). Nearly all simulation residents (96.6%) endorsed making such training mandatory, with most recommending introduction between residency years two and four.ConclusionVR Simulation-based laparoscopy training was perceived as superior across expectations, skills acquisition, and structural factors. These findings, aligned with international literature, support integrating simulation as a mandatory component of gynecology residency curricula in Poland to improve both resident competence and patient safety.

SummaryBackgroundThere is a lack of summarized information regarding the uptake of pre-exposure prophylaxis (PrEP) among HIV negative gay, bisexual and other men who have sex with men (GBMSM) who engage in chemsex. This systematic review and meta-analysis aimed to summarize, assess the quality of existing evidence, estimate the prevalence of PrEP uptake among GBMSM who engage in chemsex, based on available global evidence; and evaluate whether engagement in chemsex is associated with increased odds of PrEP uptake in this population.MethodsWe searched Medline, Embase, Cochrane Reviews and CENTRAL, APA PsycInfo, Scopus, and LILACS. We included studies reporting chemsex practices among adult cisgender GBMSM and PrEP uptake until July 1, 2025. Evidence quality was assessed using the Newcastle–Ottawa Scale tool. Chemsex exposure was analyzed using two timeframe groups: recent (past 6 months) and ever (any longer or unspecified timeframe). Prevalence and associations -odds ratio (OR)- were pooled in meta-analyses using a random-effect model. Inconsistency, sensitivity, and publication bias analyses were conducted. PROSPERO registration: CRD42024573871.FindingsAmong 3988 records screened, 28 studies comprising 36,339 participants across three world regions were included: Western and Central Europe and North America, Asia and the Pacific, and Latin America; all were rated low to moderate quality. The overall prevalence of PrEP use was 39% (95% CI: 29–49%) among GBMSM who engaged in chemsex, with no significant differences between recent and ever chemsex timeframe groups. Sensitivity analyses and meta-regressions showed no significant effect of study publication year, country income group or world region. Overall chemsex was associated with higher odds of PrEP use (OR = 3.44, 95% CI: 2.70–4.38), with a significantly stronger association for ever chemsex (OR = 4.74, 95% CI: 3.48–6.46) than for recent chemsex (OR = 2.84, 95% CI: 2.11–3.81p < 0.05). Meta-regressions indicated significantly lower odds of PrEP use in studies from low- and middle-income countries for both recent (OR = 0.54, 95% CI: 0.31–0.94; p = 0.031) and ever (OR = 0.46, 95% CI: 0.21–0.99; p = 0.046) chemsex timeframes. Heterogeneity remained moderate to high across all analyses.InterpretationOur findings suggest that PrEP use is relatively common among GBMSM who engage in chemsex globally and chemsex is consistently and strongly associated with increased PrEP uptake in this population. The association between chemsex and PrEP use was significantly higher in studies from high-income settings, where chemsex practices are better described and PrEP is more widely available for this group. The lack of standardized definitions in the field contributes to the high heterogeneity and strongly influences the generation of global evidence. This first systematic review and metanalysis in the field highlights the need to expand and integrate chemsex harm reduction and PrEP services for GBMSM, especially in low- and middle-income settings, to improve health outcomes and advance towards the global HIV elimination goals.FundingPublication fees were sponsored by the Research Group of the HIV Unit, Infectious Disease Division, Department of Medicine, Geneva University Hospitals, Geneva, Switzerland. The Covidence membership and the fees for an academic librarian developing a professional systematic search strategy were sponsored by the Research Group of the HIV Unit, Infectious Diseases Service, Hospital Clinic, and IDIBAPS, University of Barcelona, Barcelona, Spain. No further funding was received for this study.

Abstract Idiopathic retroperitoneal fibrosis (iRPF) is a rare immune-mediated fibroinflammatory disease within the spectrum of chronic periaortitis, frequently complicated by ureteral obstruction and renal involvement. While most published cohorts originate from Western Europe, North America, or East Asia, data from Eastern Europe, including Romania, remain scarce. We describe the clinical presentation, radiologic characteristics, treatment patterns, and long-term outcomes of a Romanian single-center cohort of patients with iRPF. This retrospective observational study included adult patients with iRPF managed at a tertiary referral center in Romania between 2010 and 2024. Diagnosis relied on characteristic findings on contrast-enhanced computed tomography or magnetic resonance imaging and exclusion of secondary causes. Disease extent was classified using the Scheel radiologic classification. Clinical, laboratory, imaging, treatment, and outcome data were extracted from medical charts. Remission was defined as resolution or stabilization of imaging findings combined with normalization or stabilization of renal function and inflammatory markers. Relapse was defined as recurrence of hydronephrosis, increase in retroperitoneal mass size, or disease-attributable symptoms with elevated inflammatory markers after documented remission. Twenty-three patients were included (65% male, median age at diagnosis was 55 years). Ureteral involvement was nearly universal with bilateral hydronephrosis present in 91% of cases, and vascular compression observed in over half of cases. All patients had impaired kidney function at diagnosis, with a median estimated glomerular filtration rate of 24 mL/min/1.73m2. Immunosuppressive therapy was administered to 87% of patients, most commonly systemic glucocorticoids, and 57% required urological intervention. Over a median follow-up of 12.2 years, remission occurred in 70%, relapse in 30%. Among patients with available outcome data, remission was achieved in 100% (5/5) of those receiving prednisone monotherapy and 91% (10/11) of those receiving combination immunosuppressive therapy. Infectious complications were documented in 26%, progression to end-stage kidney disease in 9%, and mortality in 35%. In this Romanian cohort, iRPF was often diagnosed at an advanced stage and associated with considerable long-term morbidity, underscoring the importance of earlier recognition.

Biomass burning aerosols (BBA) released from large-scale wildfires pose a serious threat worldwide, necessitating a comprehensive understanding of their plume characteristics. To address this challenge, this study used satellite data provided by the Second-generation Global Imager (SGLI) aboard the Global Change Observation Mission-C and regional-scale numerical chemical transport model (CTM) simulations to characterize BBA plumes. The SGLI data and CTM simulations were compared and verified, and the 3D characteristics of BBA plumes, including concentration, diffusion range, spatial variation in optical properties, plume top height, and vertical profile, were subsequently derived. In this study, we focused on large-scale forest fires that occurred in western North America in September 2020 and Indonesia in September 2019. In both cases, Aerosol optical thickness (AOT) and Ångström Exponent (AE) values show a positive correlation with the height of the BBA plume top. The results showed that the higher the BBA plume top, the thicker the plume and the smaller the aerosol size. This point is what we particularly wish to highlight in this study. The SGLI polarization data proved useful for characterizing the upper layers of the BBA plumes. By understanding the detailed characteristics at the top of the plume, it is possible to predict the BBA plume’s advection and lifetime.

Identifying the impacts of climate change and human activities on streamflow changes is essential for understanding hydrological processes and sustainable water resource management. This study investigated the spatiotemporal changes of annual streamflow in global 2264 catchments during 1961–2014, and quantified the contributions of precipitation (P), potential evapotranspiration (Ep) and landscape parameter (n) to streamflow changes using Choudhury-Yang equation based on Budyko hypothesis. The results indicated that significant increasing trends (p < 0.05) in annual streamflow (16.65%) mainly showed in northeastern North America, northern Europe, and central-southern South America, while significant decreasing trends in annual streamflow (12.01%) mainly occurred in western North America, eastern South America, southern Australia, and southwestern China during 1961–2014, which were largely consistent with the pattern of annual P trends. In general, arid and semi-arid catchments in central-southwestern North America, eastern South America, southern Africa, and Australia exhibited greater streamflow elasticities than the relatively humid catchments across eastern and northwestern North America, southern South America, Europe, and southwestern China. The P, Ep, and n dominated streamflow changes in the 50.7%, 0.9%, and 48.4% (53.1%, 2.4%, and 44.5%) of total catchments during 1986–2000 (2001–2014), respectively. The parameter n in more catchments showed positive correlations with NDVI, forest loss, cropland area, and impervious surface, and that showed negative correlations with population density and nightlight index. This study provides meaningful insights into the attribution of streamflow changes to climate change and human activities across the globe.

ABSTRACT Aim The biogeography and distribution of irruptive forest insect herbivores are driven by population level responses to host availability, temperature, and precipitation. Because the irruptive dynamics of tree‐killing insects such as spruce beetle are regulated by climate, it is imperative to quantify biogeographic drivers and limiters to develop informed predictions and forecasts of future outbreaks. Here, we: (1) identify subcontinental drivers of spruce beetle outbreak distributions, (2) compare drivers and limiters of outbreaks across regions, and (3) develop geospatial hindcasts and forecasts to evaluate the potential for shifts in outbreak activity through time. Location Western North American spruce forests spanning 33 to 68 degrees latitude. Taxon Spruce beetle ( Dendroctonus rufipennis ) and spruce trees ( Picea spp.) Methods We compiled aerial surveys of spruce beetle‐caused tree mortality from 1962 to 2023, forest inventory, and downscaled climate data to develop ensemble machine learning models to investigate patterns of recorded outbreaks and predict the historical and projected distributions of spruce beetle outbreaks. Results The distribution of spruce beetle outbreaks are best explained by minimum winter temperature, precipitation as snow, and mean growing season temperatures across western North American. Limiters of outbreaks varied regionally. Host occupancy limited the southern distribution, abundant moisture and diffuse host availability in mixed species forests constrained the western coastal distribution, and minimum winter temperature constrained the northern distribution. Hindcasts and forecasts indicate that the outbreak distribution has expanded in all regions since 1900 and will continue to expand poleward due to projected warming across the boreal. Conclusions Understanding how the distributions of forest insect outbreaks respond to fluctuations in climate will dictate the location and severity of outbreaks over the next century. Large‐scale irruptions of spruce beetle in forests with historically limited activity will lead to substantial impacts on spruce‐dominated landscapes and unknown ramifications for forest processes or long‐term disturbance regimes.