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The physics of doped Mott insulators remains controversial after decades of active research, hindered by the interplay among competing orders and fluctuations. It is thus highly desired to distinguish the intrinsic characters of the Mott-metal crossover from those of other origins. Here we investigate the evolution of electronic structure and dynamics of the hole-doped pseudospin-1/2 Mott insulator Sr 2 IrO 4 . The effective hole doping is achieved by replacing Ir with Rh atoms, with the chemical potential immediately jumping to or near the top of the lower Hubbard band. The doped iridates exhibit multiple iconic low-energy features previously observed in doped cuprates—pseudogaps, Fermi arcs and marginal-Fermi-liquid-like electronic scattering rates. We suggest these signatures are most likely an integral part of the material’s proximity to the Mott state, rather than from many of the most claimed mechanisms, including preformed electron pairing, quantum criticality or density-wave formation. The physics of Mott insulators is obscured by the interplay between competing orders and fluctuations. Here, the authors track the evolution of the electronic structure of Mott insulator strontium iridate as the iridium atoms are replaced by rhodium, providing insight into this exotic state of matter.

Gravity and shape measurements for Ceres obtained from the Dawn spacecraft mission show that it is in hydrostatic equilibrium with its inferred normalized mean moment of inertia of 0.37, suggesting that Ceres has a rocky chondritic core overlaid by a volatile-rich icy shell. Geophysical observations of dwarf planet Ceres This paper presents geophysical observations of Ceres—the closest dwarf planet to the Sun, in an orbit between those of Mars and Jupiter—based on radio tracking and onboard image data acquired by the Dawn spacecraft. Gravity and shape measurements provide a key parameter that has been unobtainable through remote observations—the moment of inertia. Ceres is shown to be in hydrostatic equilibrium with an inferred normalized mean moment of inertia of 0.37. The Dawn spacecraft data and analysis reported here give the first constraints on the interior structure of a dwarf planet. Ceres emerges as a partially differentiated body, with a rocky core overlaid by a volatile-rich icy shell. Remote observations of the asteroid (1) Ceres from ground- and space-based telescopes have provided its approximate density and shape, leading to a range of models for the interior of Ceres, from homogeneous to fully differentiated 1 , 2 , 3 , 4 , 5 , 6 . A previously missing parameter that can place a strong constraint on the interior of Ceres is its moment of inertia, which requires the measurement of its gravitational variation 1 , 7 together with either precession rate 8 , 9 or a validated assumption of hydrostatic equilibrium 10 . However, Earth-based remote observations cannot measure gravity variations and the magnitude of the precession rate is too small to be detected 9 . Here we report gravity and shape measurements of Ceres obtained from the Dawn spacecraft, showing that it is in hydrostatic equilibrium with its inferred normalized mean moment of inertia of 0.37. These data show that Ceres is a partially differentiated body, with a rocky core overlaid by a volatile-rich shell, as predicted in some studies 1 , 4 , 6 . Furthermore, we show that the gravity signal is strongly suppressed compared to that predicted by the topographic variation. This indicates that Ceres is isostatically compensated 11 , such that topographic highs are supported by displacement of a denser interior. In contrast to the asteroid (4) Vesta 8 , 12 , this strong compensation points to the presence of a lower-viscosity layer at depth, probably reflecting a thermal rather than compositional gradient 1 , 4 . To further investigate the interior structure, we assume a two-layer model for the interior of Ceres with a core density of 2,460–2,900 kilograms per cubic metre (that is, composed of CI and CM chondrites 13 ), which yields an outer-shell thickness of 70–190 kilometres. The density of this outer shell is 1,680–1,950 kilograms per cubic metre, indicating a mixture of volatiles and denser materials such as silicates and salts 14 . Although the gravity and shape data confirm that the interior of Ceres evolved thermally 1 , 4 , 6 , its partially differentiated interior indicates an evolution more complex than has been envisioned for mid-sized (less than 1,000 kilometres across) ice-rich rocky bodies.

Thermochemical models have predicted that Ceres, is to some extent, differentiated and should have an icy crust with few or no impact craters. We present observations by the Dawn spacecraft that reveal a heavily cratered surface, a heterogeneous crater distribution, and an apparent absence of large craters. The morphology of some impact craters is consistent with ice in the subsurface, which might have favored relaxation, yet large unrelaxed craters are also present. Numerous craters exhibit polygonal shapes, terraces, flowlike features, slumping, smooth deposits, and bright spots. Crater morphology and simple-to-complex crater transition diameters indicate that the crust of Ceres is neither purely icy nor rocky. By dating a smooth region associated with the Kerwan crater, we determined absolute model ages (AMAs) of 550 million and 720 million years, depending on the applied chronology model.

In this study, the radiation process in the Korean Integrated Model (KIM) is modified to calculate the cloud radiative forcing keeping a physical consistency with the microphysics, convection, and cloudiness schemes in an aspect of hydrometeor. A formula to calculate effective radii of cloud water in radiation scheme of the KIM is modified to be consistent with that in the microphysics scheme and the radiative effect of a subgrid-scale hydrometeor is considered along with convective parameterization and cloudiness schemes. The impacts of these modifications on radiation and precipitation are diagnosed via an observation comparison, and a detailed analysis of these impacts is conducted. Especially, the contrasting feedback of the subgrid-scale hydrometeor on precipitation over the land and the ocean is separately discussed.

On 29 September 2022 the Juno spacecraft flew within 354 km of Europa's surface while several instruments probed the moon's surroundings. During the close flyby, radio occultations were performed by collecting single‐frequency Doppler measurements. These investigations are essential to the study of Europa's ionosphere and represent the first repeat sampling of any set of conditions since the Galileo era. Ingress measurements resulted in a marginal detection with a peak ionospheric density of 4,000 ± 3,700 cm−3 (3σ) at 22 km altitude. A more significant detection emerged on egress, with a peak density of 6,000 ± 3,000 cm−3 (3σ) at 320 km altitude. Comparison with Galileo measurements reveals a consistent picture of Europa's ionosphere, and confirms its dependence on illumination conditions and position within Jupiter's magnetosphere. However, the overall lower densities measured by Juno suggest a dependence on time of observation, with implications for the structure of the neutral atmosphere. Plain Language Summary On 29 September 2022, NASA's Juno spacecraft flew very close to Jupiter's moon Europa. During the encounter, a radio occultation experiment was performed, where radio signals are exchanged between the spacecraft and ground stations as the former sets behind or rises from the moon as seen from the Earth. The scope of this experiment was studying the ionosphere of Europa, a layer of electrons and ions surrounding the moon. The Juno measurements confirmed the presence of the layer, with a structure similar to the one observed by the Galileo mission in the late 1990s. Key Points Europa's ionosphere was detected from Juno's X‐band Doppler data via NASA's Deep Space Network during a close encounter in 2022 Peak densities were 4,000 ± 3,700 cm−3 (3σ) at 22 km altitude during ingress and 6,000 ± 3,000 cm−3 (3σ) at 320 km during egress The Juno ionospheric profiles are consistent with Galileo measurements, and show a dependence on solar zenith and magnetospheric ram angles

A new approach to more accurately monitor and evaluate transboundary particulate matter (PM) pollution is introduced based on aerosol optical products from Korea's Geostationary Ocean Color Imager (GOCI). The area studied is Northeast Asia (including eastern parts of China, the Korean peninsula and Japan), where GOCI has been monitoring since June 2010. The hourly multi-spectral aerosol optical data that were retrieved from GOCI sensor onboard geostationary satellite COMS (Communication, Ocean, and Meteorology Satellite) through the Yonsei aerosol retrieval algorithm were first presented and used in this study. The GOCI-retrieved aerosol optical data are integrated with estimated aerosol distributions from US EPA Models-3/CMAQ (Community Multi-scale Air Quality) v4.5.1 model simulations via data assimilation technique, thereby making the aerosol data spatially continuous and available even for cloud contamination cells. The assimilated aerosol optical data are utilized to provide quantitative estimates of transboundary PM pollution from China to the Korean peninsula and Japan. For the period of 1 April to 31 May, 2011 this analysis yields estimates that AOD as a proxy for PM2.5 or PM10 during long-range transport events increased by 117–265% compared to background average AOD (aerosol optical depth) at the four AERONET sites in Korea, and average AOD increases of 121% were found when averaged over the entire Korean peninsula. This paper demonstrates that the use of multi-spectral AOD retrievals from geostationary satellites can improve estimates of transboundary PM pollution. Such data will become more widely available later this decade when new sensors such as the GEMS (Geostationary Environment Monitoring Spectrometer) and GOCI-2 are scheduled to be launched.

The atmospheric dynamics of Jupiter are dominated by strong zonal winds engulfing the planet. Since the first gravity measurements taken by Juno at Jupiter, the low-degree gravity harmonics (J3–J10) have been used to determine the depth and structure of the zonal winds observed at the cloud level, limiting inferences on the deep flows to the wide latitudinal structure of these harmonics. Here, using constraints on the dynamical contribution to gravity at high latitude, we present the gravity harmonics up to J40. We find an excellent correlation between these measurements and the gravity harmonics resulting from the observed cloud-level winds extending inwards cylindrically to depths of ~105 bar (3,000 km). These measurements provide direct evidence that the flows penetrate inwards along the direction of the spin axis, confirming the cylindrical nature of the flow, which has been postulated theoretically since the 1970s. Furthermore, this detailed new gravity spectrum allows us to quantify the contribution of the various jets to the gravity signal, showing the dominance of the strong zonal flows around 20° latitude in both hemispheres.Using NASA’s Juno mission measurements, researchers obtain a new high-precision map of Jupiter’s gravity field and confirm that the planet’s observed strong east–west jet streams penetrate inwards in a direction parallel to the planet’s spin axis.

This study focused on the contribution of ammonium nitrate (NH4NO3) to aerosol optical depth (AOD) and direct radiative forcing (DRF) by aerosols over an East Asian domain. In order to evaluate the contribution, chemistry-transport model (CTM)-estimated AOD was combined with satellite-retrieved AOD, utilizing a data assimilation technique, over East Asia for the entire year of 2006. Using the assimilated AOD and CTM-estimated aerosol optical properties, the DRF by aerosols was estimated over East Asia via a radiative transfer model (RTM). Both assimilated AOD and estimated DRF values showed relatively good agreements with AOD and DRF by aerosols from AERONET. Based on these results, the contributions of NH4NO3 to AOD and DRF by aerosols (ΦAOD and ΦDRF) were estimated for the four seasons of 2006 over East Asia. Both ΦAOD and ΦDRF showed seasonal variations over East Asia within the ranges between 4.7% (summer) and 31.3% (winter) and between 4.7% (summer) and 30.7% (winter), respectively, under clear-sky conditions, showing annual average contributions of 15.6% and 15.3%. Under all-sky conditions, ΦDRF varied between 3.6% (summer) and 24.5% (winter), showing annual average contribution of 12.1% over East Asia. These annual average contributions of NH4NO3 to AOD and DRF are almost comparable to the annual average mass fractions of NH4NO3 in PM2.5 and PM10 (17.0% and 14.0%, respectively). ΦAOD and ΦDRF were even larger in the locations where NH3 and NOx emission rates are strong, such as the central East China (CEC) region and Sichuan Basin. For example, under clear-sky conditions, both ΦAOD and ΦDRF over the CEC region range between 6.9% (summer) and 47.9% (winter) and between 6.7% (summer) and 47.5% (winter), respectively. Based on this analysis, it was concluded that both ΦAOD and ΦDRF cannot be ignored in East Asian air quality and radiative forcing studies, particularly during winter.

Direct band-gap semiconductors play the central role in optoelectronics. In this regard, monolayer (ML) MX 2 (M = Mo, W; X = S, Se) has drawn increasing attention due to its novel optoelectronic properties stemming from the direct band-gap and valley degeneracy. Unfortunately, the more practically usable bulk and multilayer MX 2 have indirect-gaps. It is thus highly desired to turn bulk and multilayer MX 2 into direct band-gap semiconductors by controlling external parameters. Here, we report angle-resolved photoemission spectroscopy (ARPES) results from Rb dosed MoSe 2 that suggest possibility for electric field induced indirect to direct band-gap transition in bulk MoSe 2 . The Rb concentration dependent data show detailed evolution of the band-gap, approaching a direct band-gap state. As ionized Rb layer on the surface provides a strong electric field perpendicular to the surface within a few surface layers of MoSe 2 , our data suggest that direct band-gap in MoSe 2 can be achieved if a strong electric field is applied, which is a step towards optoelectronic application of bulk materials.

This prospective study was conducted with the Korean Cancer Study Group to evaluate the efficacy and safety of cetuximab combined with modified FOLFOX6 (mFOLFOX6) as first-line treatment in recurrent or metastatic gastric cancer and to identify potential predictive biomarkers. Patients received cetuximab 400 mg m −2 at week 1 and 250 mg m −2 weekly thereafter until disease progression. Oxaliplatin (100 mg m −2 ) and leucovorin (100 mg m −2 ) were administered as a 2-h infusion followed by a 46-h continuous infusion of 5-fluorouracil (2400 mg m −2 ) every 2 weeks for a maximum of 12 cycles. Biomarkers potentially associated with efficacy were analysed. Among 38 evaluable patients, confirmed response rate (RR) was 50.0% (95% CI 34.1–65.9). Median time-to-progression (TTP) was 5.5 months (95% CI 4.5–6.5) and overall survival (OS) 9.9 months. Eleven patients having tumour EGFR expression by immunohistochemistry with low serum EGF and TGF- α levels showed a 100% RR compared to 37.0% in the remaining 27 patients ( P <0.001). Moreover, ligand level increased when disease progressed in seven out of eight patients with EGFR expression and low baseline ligand level. No patient exhibited EGFR amplification or K-ras mutations. Gastric cancer patients with EGFR expression and low ligand levels had better outcomes with cetuximab/mFOLFOX6 treatment.