UC Merced

Short-duration precipitation extremes can threaten public safety and infrastructure by generating flash flooding and geophysical mass wasting events including mudslides and debris flows. Using two surface gauge-based precipitation datasets (1980-2024), we characterize the climatology of annual maximum subdaily precipitation and quantify trends across the western United States (WUS) – a topographically complex region with widely varying precipitation regimes prone to flash flooding. We find that 60.7% of WUS stations, including the vast majority of those located in the continental interior, typically experience 1-hr annual maximum precipitation (AMP) during summer and during the afternoon and evening hours (12:00-23:00 local time). Although most stations do not show statistically significant trends in 1-hr AMP intensity over the full period of record (1980-2024), a significant 10.3% domain-median increase in 1-hr AMP intensity was observed during 2000-2024. These changes largely result from seasonal maximum precipitation (SMP) increases during summer over the continental interior coinciding with a trend toward more favorable summer thermodynamic environments for short-duration precipitation extremes. We also report widespread though statistically insignificant increases in SMP intensity during winter and spring in California since 2000 coinciding with increased column water vapor. These results are suggestive of potential recent intensification of subdaily precipitation extremes in a warming climate in the WUS despite a backdrop of considerable internal variability.

Abstract Cutoff lows (COL) are upper-level lows that are displaced from the jet stream and are often associated with a stagnant circulation that facilitates prolonged periods of precipitation and subsequent hydrologic hazards. Here, we quantify the contribution of COL to annual and seasonal precipitation totals, extremes, and hydrologic disasters across the globe, as well as explore how precipitation coincident with COL has changed in observations and is projected to change under future scenarios. Many locations received at least 20% of their annual precipitation coincident to COL across portions of the globe, with notable hotspots along the equatorward flank of the jet stream and in rain shadowed areas of the mid-latitudes. Further, regions – including the Mediterranean, southeastern Australia, the interior western United States (US), South Africa, and northeast China – had over a third of their three-day annual maximum precipitation events coincident with COL. We also show that an estimated 6.4% of total global economic losses from flood-related disasters outside of the equatorial zone were associated with COL during 2000-2023. Significant increases in precipitation concurrent with COL occurred during 1979-2024 in portions of Europe and the northern US and southern Canada with significant declines in eastern Australia. Projections using output from the Community Earth System Model version 2 Large Ensemble show a robust increase in COL precipitation of ~20% over the central US and eastern Europe by 2041-2070 tied to a poleward migration of the jet streams. Our results suggest that COL are an important mechanism for generating extreme precipitation and flooding impacts in many global regions, with their contribution to precipitation totals projected to rise in the coming decades in parts of the Northern Hemisphere mid-latitudes.

Effective water and thermal management are crucial for maximizing the performance of proton exchange membrane fuel cells (PEMFCs). This study presents a robust non-isothermal model that integrates two-phase flow, species transport, and heat and mass transfer phenomena to investigate water generation, accumulation, and permeation mechanisms within the gas diffusion layer (GDL) of PEMFCs. Utilizing X-ray computed tomography (XCT) reconstruction, a 2D structure of the Freudenberg GDL is generated. The model incorporates anisotropic thermal conductivity, distinguishes between in-plane and through-plane K IP K TP ratios, and demonstrates its importance to temperature distribution and subsequent condensation rate within the GDL. Additionally, our parametric analysis evaluates the effects of GDL thermal conductivity, current density, operating temperature, and pressure on water condensation and transport processes in PEMFCs. Key findings include the identification of distinct phases of condensation and transport within the porous medium under varying conditions: nucleation, growth, accumulation, and mobilization. Simulation results uncovered condensation regions within the GDL, demonstrating that temperature gradients, strongly influenced by anisotropic thermal conductivity, play a critical role in water generation and transport dynamics. The study further reveals that areas beneath the land in the GDL exhibit lower temperatures, leading to elevated condensation rates and larger droplet formation within those regions. Additionally, the interconnection of condensate droplets via wetting layers emphasizes the impact of temperature distribution on water movement. This study provides deeper insight into water vapor condensation and transport mechanisms within GDLs, informing the design and optimization of GDL structures for enhanced PEMFC performance.

The interrogation of data across biological and environmental systems has become increasingly complex. Fortunately, communities are adopting the FAIR (Findable, Accessible, Interoperable, Reusable) data principles for individual datasets, and continue to develop domain-specific, machine-actionable standards. However, integrating FAIR data for meta-analysis across data resources is still challenging. Understanding how disparate datasets are organized remains a manual, time-consuming process. Updating FAIR databases to reflect changes in knowledge is slow, allowing stale annotations and incorrect relationships to propagate, amplified by Artificial Intelligence (AI) systems that harvest data. Building on FAIR, we argue that data should be iteratively updated and improved. FAIR + COPE (Comparable, Organized, Predictive, Engaged) takes FAIR data and makes it Comparable, rapidly Organized (applying / updating standards) for Predictive models, which can be validated and improved by an Engaged community. We provide examples of FAIR + COPE resources and science use cases that highlight the importance of FAIR + COPE in scientific research.

Background and ObjectivesAtopic dermatitis (AD) is a chronic inflammatory skin disease characterized by intensely pruritic episodes and eczematous lesions. This disease is prevalent in up to 25% of children, with about half of these cases persisting into adulthood. This systematic review aims to examine two new topical therapies for AD, roflumilast and tapinarof, and investigate the adverse events  associated with their use.MethodsA systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and registered in PROSPERO (CRD420251066719). A search was performed in Scopus, Embase, PubMed, Cochrane Library, and Web of Science on 2 June 2025. Randomized controlled trials were included if they reported adverse event outcomes in pediatric patients with AD after either roflumilast or tapinarof treatment; studies with mixed pediatric and adult patients were eligible for inclusion. Studies were excluded if they lacked roflumilast or tapinarof treatment, did not include pediatric patients with AD, or did not report adverse event outcomes. Risk of bias was assessed using the Cochrane Risk of Bias tool. Adverse events were reported as occurrence (n) and frequency (n/N, %) within pooled studies for the roflumilast and tapinarof groups. Risk ratios (RR) and 95% confidence intervals (CI) comparing treatment with vehicle control were calculated using the Mantel–Haenszel fixed-effect model.ResultsSeven studies with a total of 3615 patients with AD using roflumilast (N = 1979), tapinarof (N = 658), or vehicle control (N = 978) were included in the final data extraction and analysis. Analyses included adverse event outcomes for mixed pediatric and adult patients. Three studies assessed once-daily 0.05% or 0.15% roflumilast cream use in patients with a mean age of 19.8 years. Four studies assessed once-daily 0.5% or 1% tapinarof cream use in patients with a mean age of 8.15 years. Both therapies displayed significant risks of treatment-emergent adverse events (TEAE) compared with vehicle controls (roflumilast: RR = 1.46, 95% CI = [1.20–1.77] with p = 0.0001; tapinarof: RR = 1.49, 95% CI = [1.24–1.79], p < 0.0001). Treatment-related TEAEs were significantly increased with roflumilast use (RR = 1.92, 95% CI = [1.15–3.19], p = 0.01), but not tapinarof use (RR = 1.30, 95% CI = [0.89-1.91], p = 0.17). Roflumilast was associated with nondermatologic adverse events, while tapinarof was found to have an association with dermatologic adverse events.ConclusionsSome limitations include the lack of direct comparative studies, limited data in pediatric and young adult populations, and heterogeneity of reported adverse events. Despite this, roflumilast and tapinarof demonstrate distinct adverse event profiles. Roflumilast was associated with an increased risk of treatment-related and nondermatologic adverse events, while tapinarof was associated with dermatologic adverse events. These findings highlight the importance of individualized treatment selection and careful monitoring of adverse events  when incorporating these therapies into the management of atopic dermatitis.

China has undergone rapid economic changes in recent years, yet little is known about how children in China understand the social status hierarchies around them. The present study addressed this gap by examining whether Chinese children held essentialist beliefs about two social status categories: residency, an important but understudied status-related category in China, and socioeconomic status (SES). We also examined whether children's beliefs about these categories varied with their age or their own social status background (residency, subjective SES). Chinese 5- to 9-year-old children (47 female) who held residency in a prestigious megacity (N = 50) or less prestigious non-megacities (N = 50) completed two tasks that measured whether they viewed residency and SES as biologically based or causally informative, two dimensions of essentialism. Results suggested that children viewed residency but not SES as biologically based, though this decreased with age. Children from megacities with higher subjective SES were more likely to view residency as causally informative with age, suggesting children with higher social status are more likely to essentialize this status-related category. Children's beliefs about SES did not vary with their social-status background. These findings suggest that the developmental trajectory of Chinese children's essentialist beliefs about social status vary across status-related categories, dimensions of essentialism, and their own social-status background.

A major challenge in identifying massive quiescent galaxies at z > 3 is distinguishing truly passive systems from dust-obscured star-forming galaxies, as both populations exhibit similar red ultraviolet-to-near-infrared colors. In this work, we present Atacama Large Millimeter/submillimeter Array (ALMA) Band 7 continuum observations of five ultramassive galaxies (UMGs; log(M⋆/M⊙)>11 ) from the Massive Ancient Galaxies At z > 3 NEar-infrared survey, spectroscopically confirmed at zspec > 3. One UMG is weakly detected at 872 μm while the remaining four UMGs are undetected down to the 3σ depth. By incorporating ALMA constraints and far-infrared-to-radio photometry into the spectral energy distribution (SED) analysis, we demonstrate that all five UMGs are quiescent, lying significantly 1 dex below the star-forming main sequence. We estimate dust masses using both SED modeling and modified blackbody fitting, with consistent results between the two methods. Our results reveal the diversity in dust content among the quiescent UMGs at z > 3. While the lone ALMA-detected UMG retains a modest dust reservoir, the majority have dust-to-stellar mass ratios of Mdust/M⋆ ≲ 10−4, placing them among the most massive and extremely dust-poor spectroscopically confirmed quiescent galaxies known at z > 3. Our results support an evolutionary scenario of rapid quenching and dust removal for the most massive galaxies in the early Universe.