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Abstract Based on a template-matching method, we estimate the barium (Ba) abundances for stellar spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Medium-Resolution Spectroscopic Survey (MRS). The Ba abundances of 198,011 stars have been determined from MRS spectra with signal-to-noise ratios (S/N) > 40 combined with the stellar atmospheric parameters from the LAMOST Low-Resolution Spectroscopic Survey DR9 by the LAMOST Stellar Parameter Pipeline. The uncertainties in the Ba abundances from the LAMOST MRS spectra are less than 0.3 dex when S/N exceeds 40, which align closely with the results based on the high-resolution UVES spectra from the Gaia-ESO survey obtained by spectral synthesis. Further analysis of Ba abundances from repeated observations of the same stars reveals that random errors related to spectral quality remain below 0.3 dex at the same S/N, with a systematic overestimation for the low-S/N spectra. This extensive sample of stellar Ba abundances will enhance studies of thes-,i-, andr-processes, and deepen our understanding of the chemical-evolution history of the Milky Way. 

Abstract R-process-enhanced (RPE) stars are rare and typically metal-poor ([Fe/H]  < −1.0), primarily found in the Milky Way halo system and dwarf galaxies. This study reports the discovery of two relatively bright, highly RPE stars ([Eu/Fe]  >  +0.70) located in the Milky Way disk, with [Fe/H] of −0.34 and −0.80, respectively. These two stars are selected from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope medium-resolution (R ∼ 7500) spectroscopic survey. Follow-up high-resolution (R ∼ 25,000) observations were conducted with the High Optical Resolution Spectrograph installed on the 10.4 m Gran Telescopio Canarias. We perform the determination of elemental abundances and calculate the orbital parameters. We find that they arer-II stars with elemental abundances in agreement with the solarr-process pattern. These two objects are chemically and dynamically consistent with membership in the Galactic disk and exhibit no evidence of being part of accreted systems. 

Abstract The westward-propagating convectively coupled equatorial wave (CCEW) variability produced by an idealized general circulation model (GCM) is investigated. The model is a zonally symmetric aquaplanet with a slab ocean. Water vapor in the model may condense and produce latent heating, but there is no parameterization of cloud processes, only a quasi-equilibrium convection scheme. The CCEWs produced by the model are found to be sensitive to the heat capacity of the slab and the strength of surface friction. In spectral space, the westward-propagating precipitation variability in the model is dominated by sharp peaks in spectral power at zonal wavenumbers 5 and 6. These precipitation peaks are situated along the dispersion curve of the Rossby–Haurwitz waves, suggesting a connection between the global Rossby modes and precipitation variability. Composites of these disturbances reveal global circulation patterns that extend into the midlatitudes. The moisture variance budget of these disturbances shows that moisture advection by the global Rossby modes maintains the accompanying moisture signal. This is interpreted as downgradient advection of the background moisture gradient of the intertropical convergence zone. The locations of the precipitation peaks are sensitive to Doppler shifting by the zonal winds; when this Doppler shift becomes too weak, the frequencies of the global Rossby modes become too high to effectively couple to convection. A linearized primitive equation model shows that the presence of vertical shear in the background zonal winds is vital for producing a forced response that resembles the modes produced by the GCM. The forced response of the linear model is optimally located to enhance the original circulation of the global mode. 

Abstract Highlyr-process-enhanced (RPE) stars are rare and usually metal poor ([Fe/H] < −1.0), and they mainly populate the Milky Way halo and dwarf galaxies. This study presents the discovery of a relatively bright (V= 12.72), highly RPE (r-II) star ([Eu/Fe] = +1.32, [Ba/Eu] = −0.95), LAMOST J020623.21+494127.9. This star was selected from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope medium-resolution (R∼ 7500) spectroscopic survey; follow-up high-resolution (R∼ 25,000) observations were conducted with the High Optical Resolution Spectrograph installed on the Gran Telescopio Canarias. The stellar parameters (T_eff= 4130 K, $\log \mathrm{g}$= 1.52, [Fe/H] = −0.54,ξ= 1.80 km s⁻¹) have been inferred taking into account nonlocal thermodynamic equilibrium effects. The abundances of [Ce/Fe], [Pr/Fe], and [Nd/Fe] are +0.19, +0.65, and +0.64, respectively, relatively low compared to the Solarr-process pattern normalized to Eu. This star has a high metallicity ([Fe/H] = −0.54) compared to most other highly RPE stars and has the highest measured abundance ratio of Eu to H ([Eu/H] = +0.78). It is classified as a thin-disk star based on its kinematics and does not appear to belong to any known stream or dwarf galaxy. 

Here, we show that the Last Glacial Maximum (LGM) provides a stronger constraint on equilibrium climate sensitivity (ECS), the global warming from increasing greenhouse gases, after accounting for temperature patterns. Feedbacks governing ECS depend on spatial patterns of surface temperature (“pattern effects”); hence, using the LGM to constrain future warming requires quantifying how temperature patterns produce different feedbacks during LGM cooling versus modern-day warming. Combining data assimilation reconstructions with atmospheric models, we show that the climate is more sensitive to LGM forcing because ice sheets amplify extratropical cooling where feedbacks are destabilizing. Accounting for LGM pattern effects yields a median modern-day ECS of 2.4°C, 66% range 1.7° to 3.5°C (1.4° to 5.0°C, 5 to 95%), from LGM evidence alone. Combining the LGM with other lines of evidence, the best estimate becomes 2.9°C, 66% range 2.4° to 3.5°C (2.1° to 4.1°C, 5 to 95%), substantially narrowing uncertainty compared to recent assessments. 

ABSTRACT Terpenes are among the oldest and largest class of plant-specialized bioproducts that are known to affect plant development, adaptation, and biological interactions. While their biosynthesis, evolution, and function in aboveground interactions with insects and individual microbial species are well studied, how different terpenes impact plant microbiomes belowground is much less understood. Here we designed an experiment to assess how belowground exogenous applications of monoterpenes (1,8-cineole and linalool) and a sesquiterpene (nerolidol) delivered through an artificial root system impacted its belowground bacterial and fungal microbiome. We found that the terpene applications had significant and variable impacts on bacterial and fungal communities, depending on terpene class and concentration; however, these impacts were localized to the artificial root system and the fungal rhizosphere. We complemented this experiment with pure culture bioassays on responsive bacteria and fungi isolated from the sorghum rhizobiome. Overall, higher concentrations (200 µM) of nerolidol were inhibitory toFerrovibriumand tested Firmicutes. While fungal isolates ofPenicilliumandPericoniawere also more inhibited by higher concentrations (200 µM) of nerolidol,Clonostachyswas enhanced at this higher level and together withHumicolawas inhibited by the lower concentration tested (100 µM). On the other hand, 1,8-cineole had an inhibitory effect onOrbiliaat both tested concentrations but had a promotive effect at 100 µM onPenicilliumandPericonia. Similarly, linalool at 100 µM had significant growth promotion inMortierella, but an inhibitory effect forOrbilia. Together, these results highlight the variable direct effects of terpenes on single microbial isolates and demonstrate the complexity of microbe-terpene interactions in the rhizobiome. ImportanceTerpenes represent one of the largest and oldest classes of plant-specialized metabolism, but their role in the belowground microbiome is poorly understood. Here, we used a “rhizobox” mesocosm experimental set-up to supply different concentrations and classes of terpenes into the soil compartment with growing sorghum for 1 month to assess how these terpenes affect sorghum bacterial and fungal rhizobiome communities. Changes in bacterial and fungal communities between treatments belowground were characterized, followed by bioassays screening on bacterial and fungal isolates from the sorghum rhizosphere against terpenes to validate direct microbial responses. We found that microbial growth stimulatory and inhibitory effects were localized, terpene specific, dose dependent, and transient in time. This work paves the way for engineering terpene metabolisms in plant microbiomes for improved sustainable agriculture and bioenergy crop production. 

In this paper, we develop via real variable methods various characterisations of the Hardy spaces in the multi-parameter flag setting. These characterisations include those via, the non-tangential and radial maximal function, the Littlewood–Paley square function and area integral, Riesz transforms and the atomic decomposition in the multi-parameter flag setting. The novel ingredients in this paper include (1) establishing appropriate discrete Calderón reproducing formulae in the flag setting and a version of the Plancherel–Pólya inequalities for flag quadratic forms; (2) introducing the maximal function and area function via flag Poisson kernels and flag version of harmonic functions; (3) developing an atomic decomposition via the finite speed propagation and area function in terms of flag heat semigroups. As a consequence of these real variable methods, we obtain the full characterisations of the multi-parameter Hardy space with the flag structure. 

Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection of solar radiation and reduce the amount of energy absorbed by the climate system. From the physical science perspective, the consensus of a broad international group of scientists is that the viability of MCB will ultimately depend on whether observations and models can robustly assess the scale-up of local-to-global brightening in today’s climate and identify strategies that will ensure an equitable geographical distribution of the benefits and risks associated with projected regional changes in temperature and precipitation. To address the physical science knowledge gaps required to assess the societal implications of MCB, we propose a substantial and targeted program of research—field and laboratory experiments, monitoring, and numerical modeling across a range of scales.