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Drylands cover 41% of Earth’s surface and are the largest source of interannual variability in the global carbon sink. Drylands are projected to experience accelerated expansion over the next century, but the implications of this expansion on variability in gross primary production (GPP) remain elusive. Here we show that by 2100 total dryland GPP will increase by 12 ± 3% relative to the 2000–2014 baseline. Because drylands will largely expand into formerly productive ecosystems, this increase in dryland GPP may not increase global GPP. Further, GPP per unit dryland area will decrease as degradation of historical drylands outpaces the higher GPP of expanded drylands. Dryland expansion and climate-induced conversions among sub-humid, semi-arid, arid, and hyper-arid subtypes will lead to substantial changes in regional and subtype contributions to global dryland GPP variability. Our results highlight the vulnerability of dryland subtypes to more frequent and severe climate extremes and suggest that regional variations will require different mitigation strategies. Earth’s drylands are expected to expand due to climate change, but how this will affect vegetation remains unclear. Here the authors use models to show that despite expansion, primary productivity in drylands is likely to increase through the 21st Century.

Atmospheric flow over complex terrain, particularly recirculation flows, greatly influences wind-turbine siting, forest-fire behaviour, and trace-gas and pollutant dispersion. However, there is a large uncertainty in the simulation of flow over complex topography, which is attributable to the type of turbulence model, the subgrid-scale (SGS) turbulence parametrization, terrain-following coordinates, and numerical errors in finite-difference methods. Here, we upgrade the large-eddy simulation module within the Weather Research and Forecasting model by incorporating the immersed-boundary method into the module to improve simulations of the flow and recirculation over complex terrain. Simulations over the Bolund Hill indicate improved mean absolute speed-up errors with respect to previous studies, as well an improved simulation of the recirculation zone behind the escarpment of the hill. With regard to the SGS parametrization, the Lagrangian-averaged scale-dependent Smagorinsky model performs better than the classic Smagorinsky model in reproducing both velocity and turbulent kinetic energy. A finer grid resolution also improves the strength of the recirculation in flow simulations, with a higher horizontal grid resolution improving simulations just behind the escarpment, and a higher vertical grid resolution improving results on the lee side of the hill. Our modelling approach has broad applications for the simulation of atmospheric flows over complex topography.

Background Myocardial infarction (MI) is a leading cause of global mortality. Ferroptosis, an iron-dependent form of programmed cell death, has recently emerged as a critical player in cardiovascular diseases. N6-methyladenosine (m6A), the most prevalent RNA methylation modification in eukaryotic cells, has been implicated in various pathological processes; however, its regulatory role in MI through ferroptosis remains poorly understood. This study aimed to elucidate the mechanism by which m6A methylation mediates MI via ferroptosis. Methods A hypoxia/reoxygenation (H/R) model was established using H9C2 cells to simulate myocardial injury. RNA methylation levels were quantified via dot blot assay. Ferroptosis was evaluated by measuring lactate dehydrogenase (LDH) release, Fe 2+ levels, glutathione (GSH), lipid reactive oxygen species (ROS), malondialdehyde (MDA), and apoptosis. The underlying molecular mechanisms were investigated using western blotting, quantitative real-time PCR (qPCR), methylated RNA immunoprecipitation (MeRIP), and RIP. Findings were further validated in a myocardial ischemia/reperfusion injury (MIRI) rat model. Results The results revealed that m6A levels were significantly elevated in the H/R cell model, accompanied by reduced expression of Alkbh5 mRNA. Moreover, Alkbh5 overexpression inhibited ferroptosis increased in the H/R model. Mechanistically, Alkbh5 overexpression decreased m6A levels of Ythdf1 and H9C2 cells while promoting Fth1 translation by enhancing Ythdf1 mRNA expression. Knockdown of Ythdf1 restored ferroptosis in the H/R model, counteracting the effects of Alkbh5 overexpression. Furthermore, Alkbh5 overexpression alleviated myocardial injury in the MIRI rat model, upregulated Ythdf1 mRNA expression, and increased Fth1 protein levels. Conclusion This study demonstrates that Alkbh5 ameliorates MI by inhibiting ferroptosis through m6A demethylation of Fth1. These findings provide novel insights into the molecular mechanisms underlying MI and highlight potential therapeutic targets for MI treatment.

Chinese goldthread ( Coptis chinensis Franch.), a member of the Ranunculales, represents an important early-diverging eudicot lineage with diverse medicinal applications. Here, we present a high-quality chromosome-scale genome assembly and annotation of C. chinensis . Phylogenetic and comparative genomic analyses reveal the phylogenetic placement of this species and identify a single round of ancient whole-genome duplication (WGD) shared by the Ranunculaceae. We characterize genes involved in the biosynthesis of protoberberine-type alkaloids in C. chinensis . In particular, local genomic tandem duplications contribute to member amplification of a Ranunculales clade-specific gene family of the cytochrome P450 (CYP) 719. The functional versatility of a key CYP719 gene that encodes the ( S )-canadine synthase enzyme involved in the berberine biosynthesis pathway may play critical roles in the diversification of other berberine-related alkaloids in C. chinensis . Our study provides insights into the genomic landscape of early-diverging eudicots and provides a valuable model genome for genetic and applied studies of Ranunculales. Coptis chinensis represents an early-diverging eudicot lineage with diverse medicinal applications. Here, the authors report its chromosome-scale genome assembly, infer a single ancient whole-genome duplication, and characterize the function of CYP719 in diversification of protoberberine-type alkaloids.

In this paper, graphene reinforced aluminum matrix composites are successfully prepared by high-energy ball milling. The results show that no graphene agglomeration is found in the mixed powder. The complex composites prepared by high energy ball milling and powder metallurgy have approximately 4–5 layers of graphene and the thickness of single-layer graphene is approximately 0.334 nm. The final experimental results confirm the formation of compound AlC 3 in the microstructure, and its diffraction spot index is ( 2 ¯ 00), ( 1 ¯ 1 1 ¯ ) and (11 1 ¯ ). The maximum friction coefficient is 0.126, and the average friction coefficient is 0.027, suggesting good wear resistance and corrosion resistance. Additionally, the friction corrosion mechanism of the material is deeply analyzed. The results of strengthening mechanism analysis show that the main strengthening mechanism of the materials designed in this experiment is thermal mismatch strengthening. It can be concluded that the yield strength of the material calculated by the modified model is 227.75 MPa. This value is slightly lower than the calculated value of the general shear lag model (237.68 MPa). However, it is closer to the yield strength value of the actual material (211 MPa).

An “inverse‐temperature layer” (ITL) of water temperature increasing with depth is predicted based on physical principles and confirmed by in situ observations. Water temperature and other meteorological data were collected from a fixed platform in the middle of a shallow inland lake. The ITL persists year‐around with its depth on the order of one m varying diurnally and seasonally and shallower during daytimes than nighttimes. Water surface heat flux derived from the ITL temperature distribution follows the diurnal cycle of solar radiation up to 300 W m−2 during daytime and down to 50 W m−2 during nighttime. Solar radiation attenuation in water strongly influences the ITL dynamics and water surface heat flux. Water surface heat flux simulated by two non‐gradient models independent of temperature gradient, wind speed and surface roughness using the data of surface temperature and solar radiation is in close agreement with the ITL based estimates. Plain Language Summary Heat stored in water bodies resulting from the absorption of solar radiation is the energy supply of evaporation and sensible heat flux into the atmosphere from water surface. Transfer of the thermal energy from water body into the atmosphere is only possible when water temperature increasing with depth within the top water layer referred to as the “inverse temperature layer (ITL).” The existence and persistence of the theoretically predicted phenomenon are demonstrated by the field observations of water temperature profile at an inland lake. The ITL depth is found to be comparable to the penetration depth of solar radiation with evident diurnal and seasonal cycles following closely those of solar radiation. Further understanding and analysis of the ITL process require higher resolution data of water temperature and solar radiation profiles within the top‐layer than those commonly collected in previous field experiments. Key Points Inverse temperature layer (ITL) allows transfer of heat from water into atmosphere ITL has prounced diurnal seasonal cycles persisting year‐around Water surface heat flux is simulated using non‐gradient models

The inverse temperature layer (ITL) beneath water‐atmosphere interface within which temperature increases with depth has been observed from measurement of water temperature profile at an inland lake. Strong solar radiation combined with moderate wind‐driven near‐surface turbulence leads to the formation of a pronounced diurnal cycle of the ITL predicted by a physical heat transfer model. The ITL only forms during daytime when solar radiation intensity exceeds a threshold while consistently occurs during nighttime. The largest depth of the ITL is comparable to the e‐fold penetration depth of solar radiation during daytime and at least one order of magnitude deeper during nighttime. The dynamics of the ITL depth variation simulated by a physical model forced by observed water surface solar radiation and temperature is confirmed by the observed water temperature profile in the lake. Plain Language Summary An idealized one‐dimensional heat transfer equation reveals the physical mechanisms of water temperature increasing with depth beneath the water‐atmosphere interface known as inverse temperature layer (ITL). Solar radiation is the dominant forcing of water temperature profile while wind‐driven turbulent mixing is a critical process determining whether the ITL forms. The limited depth of the ITL poses a constraint on the rate of heat transfer from the water body into the atmosphere. The dynamics of the ITL plays an important role in the water and energy cycle of large water bodies such as lakes and oceans. Key Points The formation of inverse temperature layer (ITL) is driven by strong solar radiation and moderate wind‐driven turbulence The ITL depth has pronounced diurnal cycle shallower during daytime than during nighttime A physical model using observed solar radiation and water surface temperature captures the ITL dynamics

It is well known that the sum of the turbulent sensible and latent heat fluxes as measured by the eddy-covariance method is systematically lower than the available energy (i.e., the net radiation minus the ground heat flux). We examine the separate and joint effects of diurnal and spatial variations of surface temperature on this flux imbalance in a dry convective boundary layer using the Weather Research and Forecasting model. Results show that, over homogeneous surfaces, the flux due to turbulent-organized structures is responsible for the imbalance, whereas over heterogeneous surfaces, the flux due to mesoscale or secondary circulations is the main contributor to the imbalance. Over homogeneous surfaces, the flux imbalance in free convective conditions exhibits a clear diurnal cycle, showing that the flux-imbalance magnitude slowly decreases during the morning period and rapidly increases during the afternoon period. However, in shear convective conditions, the flux-imbalance magnitude is much smaller, but slightly increases with time. The flux imbalance over heterogeneous surfaces exhibits a diurnal cycle under both free and shear convective conditions, which is similar to that over homogeneous surfaces in free convective conditions, and is also consistent with the general trend in the global observations. The rapid increase in the flux-imbalance magnitude during the afternoon period is mainly caused by the afternoon decay of the turbulent kinetic energy (TKE). Interestingly, over heterogeneous surfaces, the flux imbalance is linearly related to the TKE and the difference between the potential temperature and surface temperature, ΔT; the larger the TKE and ΔT values, the smaller the flux-imbalance magnitude.

Background The burden of cardiovascular disease (CVD) is severe worldwide. Although many studies have investigated the association of particulate pollution with CVD, the effect of finer particulate pollution components on CVD remains unclear. This study aimed to explore the effect of five PM 2.5 components ( , sulfate; , nitrate; , ammonium; OM, organic matter; BC, carbon black) on CVD admission in Shanghai City, identify the susceptible population, and provide clues for the prevention and control of particulate pollution. Methods Daily PM 2.5 components data during 2013–2019 in three districts of Shanghai were obtained from Tracking Air Pollution in China. We obtained CVD daily admissions data from relevant departments of Tongji Hospital, including basic information (sex, age, time of admissions, ICD code of root cause of admissions, etc.). First, generalized additive model (GAM) and distributed lag non-linear (DLNM) model were used to evaluate the individual effects of PM 2.5 components on CVD admission in three districts of Shanghai. Then, the three regions were pooled for analysis using either a random-effects model or a fixed-effects model. Results Overall, all five PM 2.5 components had significant effects on CVD admission risk. BC and OM were strongly associated with daily CVD admissions, with increasing interquartile range of the concentrations, the maximum values of cumulative RR (95% CI) were 1.318 (95%CI: 1.222–1.415) and 1.243 (95%CI: 1.164–1.322), respectively. The elderly (≥ 65 years old) was more sensitive to the four PM 2.5 components than the young population. and BC were strongest associated with CVD admissions in the elderly than in younger people, with increasing interquartile range of the concentrations, the maximum cumulative RR (95% CI) was 1.567 (95% CI: 1.116–2.019) and 1.534 (95% CI: 1.104–1.963), respectively. Conclusions This study found that five PM 2.5 components were significant risk factors for CVD admissions and specific CVD diseases in Shanghai City. The elderly were susceptible to , , OM, and BC.

Forest canopies play a critical role in affecting momentum and scalar transfer. Although there have been recent advances in numerical simulations of turbulent flows and scalar transfer across plant canopies and the atmosphere interface, few models have incorporated all important physical and physiological processes in subcanopy layers. Here we describe and evaluate an advanced multiple‐layer canopy module (MCANOPY), which is developed based largely on the Community Land Model version 4.5 and then coupled with the Weather Research and Forecasting model with large‐eddy simulations (WRF‐LES). The MCANOPY includes a suite of subcanopy processes, including radiation transfer, photosynthesis, canopy layer energy balance, momentum drag, and heat, water vapor, and CO2 exchange between canopy layers and the canopy atmosphere. Numerical schemes for heat and water transport in soil, ground surface energy balance, and soil respiration are also included. Both the stand‐alone MCANOPY and the coupled system (the WRF‐LES‐MCANOPY) are evaluated against data measured in the Canopy Horizontal Array Turbulence Study field experiment. The MCANOPY performs reasonably well in reproducing vertical profiles of mean and turbulent flows as well as second‐order statistical quantities including heat and scalar fluxes within the canopy under unstable stability conditions. The coupled WRF‐LES‐MCANOPY captures major features of canopy edge flows under both neutral and unstable conditions. Limitations of the MCANOPY are discussed for our further work. Our results suggest that our model can be a promising modeling system for a variety of applications to study canopy flows and scalar transport (e.g., CO2). Key Points An advanced multiple‐layer canopy module (MCANOPY), based largely on the Community Land Model (CLM), is developed and coupled with the WRF‐LES model Both the stand‐alone and coupling modes of the MCANOPY are evaluated against observations The model performs well in simulating subcanopy processes, canopy edge flows, and scalar transport under unstable and neutral stability conditions