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Coronal mass ejections are explosive plasma phenomena prevalently occurring on the Sun and probably on other magnetically active stars. However, how their pre-eruptive configuration evolves toward the main explosion remains elusive. Here, based on comprehensive observations of a long-duration precursor in an event on 2012 March 13, we determine that the heating and slow rise of the pre-eruptive hot magnetic flux rope (MFR) are achieved through a precursor reconnection located above cusp-shaped high-temperature precursor loops. It is observed that the hot MFR threads are built up continually, with their middle initially showing an “M” shape and then being separated from the cusp of precursor loops, causing the slow rise of the entire MFR. The slow rise, in combination with the thermal-dominated hard X-ray source concentrated at the top of the precursor loops, shows that the precursor reconnection is much weaker than the flare reconnection of the main eruption. We also perform a 3D magnetohydrodynamics simulation that reproduces the early evolution of the MFR transiting from the slow to fast rise. It is revealed that the magnetic tension force pertinent to “M”-shaped threads drives the slow rise, which, however, evolves into a magnetic pressure gradient-dominated regime responsible for the rapid acceleration eruption.

Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s −1 and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona. Magnetic reconnection is a fundamental energy release mechanism in space and laboratory plasmas. Here, the authors show persistent magnetic null-point reconnection in the solar corona at a scale of about 390 km.

We present direct metric-decimetric radio imaging observations of a fascinating quiescent filament eruption on 2024 March 17 using data from the DAocheng Radio Telescope, with a combination of the Solar Dynamics Observatory and the Chinese Hα Solar Explorer. At the radio band, even though the filament is difficult to identify in its early phase, it rapidly became distinct and formed a continuous loop-like dark structure during the eruption, i.e., so-called radio depression. Compared with the fragmentation of the erupting filament observed at the Hα and EUV bands, the radio depression appeared more coherently. Based on synthetic radio images from a three-dimensional magnetohydrodynamics simulation of a flux-rope-filament eruption, it is suggested that the radio depression originates from the absorption of cold and dense materials within the erupting flux rope to the background emission. The absorption seems to be stronger than that at the Hα and EUV bands, thus leading to their apparent discrepancies. Moreover, the radio depression is also found to occupy the lower part but not the whole body of the flux rope.

Glucocorticoids are widely used in the treatment of human glomerular diseases, but their mode of action is poorly understood particularly in steroid-sensitive nephrotic syndrome, which is most common in childhood and is characterized by a lack of inflammation in the kidney. The podocyte is a key cell in the glomerulus in health and disease: until recently, human podocytes have been difficult to study in vitro. We have developed a conditionally immortalized human podocyte cell line transfected with a temperature-sensitive simian virus 40 transgene: when the transgene is inactivated in vitro, these cells adopt the phenotype of differentiated podocytes. We have used these cells to evaluate, using immunocytochemistry, reverse transcriptase-polymerase chain reaction, and Western blotting, direct effects of the glucocorticoid dexamethasone at concentrations designed to mimic in vivo therapeutic corticosteroid levels. Dexamethasone upregulated expression of nephrin and tubulin-α, and downregulated vascular endothelial growth factor. Effects on cell cycle were complex with downregulation of cyclin kinase inhibitor p21 and augmentation of podocyte survival, without any effect on apoptosis. We report cytokine production by human podocytes, especially interleukin (IL)-6 and -8; IL-6 expression was suppressed by dexamethasone. These potent direct effects on podocytes illustrate a novel mode of action of glucocorticoids and suggest potential new therapeutic strategies for glomerular disease.

This phase 3, randomized trial in China compared the efficacy and safety of roxadustat, an oral hypoxia-inducible factor prolyl hydroxylase inhibitor, with placebo for anemia in patients with CKD who were not undergoing dialysis. Roxadustat was superior to placebo in increasing and maintaining hemoglobin levels.

This randomized, phase 3 trial compared the effectiveness of roxadustat, an oral hypoxia-inducible factor prolyl hydroxylase inhibitor, with epoetin alfa in patients undergoing hemodialysis or peritoneal dialysis in China. Oral roxadustat was noninferior to parenteral epoetin alfa as therapy for anemia.

Stratospheric aerosol injection (SAI) and marine cloud brightening (MCB) are two proposed methods of compensating for greenhouse gas‐induced warming by reflecting incoming solar radiation. However, their effects on the El Niño–Southern Oscillation (ENSO), a critical mode of climate variability, are poorly understood. Here we use ensembles of climate model simulations to show that deploying MCB in the subtropical eastern Pacific dramatically reduces ENSO amplitude by approximately 61%, while SAI has a negligible impact. MCB increases cloud albedo, which cools the subtropical eastern Pacific and triggers a loss of moist static energy. This cooling promotes atmospheric subsidence, dries the tropical Pacific, and intensifies the trade winds. The ultimate effect is a dramatic reduction in all air‐sea feedback processes operating during ENSO, which we demonstrate using a mixed‐layer heat budget. This contrast between the MCB and SAI impacts on ENSO shows that the choice of climate intervention strategy used to mitigate global warming has drastic regional implications. Plain Language Summary Global warming has significantly impacted human societies and ecosystems over the past several decades. Solar geoengineering offers a potential way to cool the planet by reflecting sunlight, including two popular approaches: stratospheric aerosol injection (SAI), which cools the atmosphere by mimicking volcanic eruptions, and marine cloud brightening (MCB), which increases the reflectivity of low ocean clouds by adding sea salt aerosols. Because the El Niño‐Southern Oscillation (ENSO)—a key climate pattern in the tropical Pacific—strongly affects global temperature and precipitation, it is crucial to understand how these methods might alter ENSO. Our climate model simulations show that subtropical eastern Pacific MCB reduces ENSO variability by about 61% by cooling the subtropical eastern Pacific, strengthening the trade winds, and suppressing essential ocean‐atmosphere interactions, while SAI has little to no effect on ENSO variability. These findings underscore the need to thoroughly assess the broader impacts of solar geoengineering to avoid unintended consequences. Key Points Marine cloud brightening in the eastern Pacific cuts El Niño‐Southern Oscillation (ENSO) amplitude through limiting key air‐sea interactions Stratospheric aerosol injection shows little effect on ENSO variability The ENSO response to cloud brightening shows the need to assess geoengineering's impacts on variability in addition to the mean state

Undesired coupling to the surrounding environment destroys long-range correlations in quantum processors and hinders coherent evolution in the nominally available computational space. This noise is an outstanding challenge when leveraging the computation power of near-term quantum processors 1 . It has been shown that benchmarking random circuit sampling with cross-entropy benchmarking can provide an estimate of the effective size of the Hilbert space coherently available 2 – 8 . Nevertheless, quantum algorithms’ outputs can be trivialized by noise, making them susceptible to classical computation spoofing. Here, by implementing an algorithm for random circuit sampling, we demonstrate experimentally that two phase transitions are observable with cross-entropy benchmarking, which we explain theoretically with a statistical model. The first is a dynamical transition as a function of the number of cycles and is the continuation of the anti-concentration point in the noiseless case. The second is a quantum phase transition controlled by the error per cycle; to identify it analytically and experimentally, we create a weak-link model, which allows us to vary the strength of the noise versus coherent evolution. Furthermore, by presenting a random circuit sampling experiment in the weak-noise phase with 67 qubits at 32 cycles, we demonstrate that the computational cost of our experiment is beyond the capabilities of existing classical supercomputers. Our experimental and theoretical work establishes the existence of transitions to a stable, computationally complex phase that is reachable with current quantum processors. By implementing random circuit sampling, experimental and theoretical results establish the existence of transitions to a stable, computationally complex phase that is reachable with current quantum processors.

Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) and lidar measurements were performed in Shanghai, China, during May 2016 to investigate the vertical distribution of summertime atmospheric pollutants. In this study, vertical profiles of aerosol extinction coefficient, nitrogen dioxide (NO2) and formaldehyde (HCHO) concentrations were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO) algorithm, while vertical distribution of ozone (O3) was obtained from an ozone lidar. Sensitivity study of the MAX-DOAS aerosol profile retrieval shows that the a priori aerosol profile shape has significant influences on the aerosol profile retrieval. Aerosol profiles retrieved from MAX-DOAS measurements with Gaussian a priori profile demonstrate the best agreements with simultaneous lidar measurements and vehicle-based tethered-balloon observations among all a priori aerosol profiles. Tropospheric NO2 vertical column densities (VCDs) measured with MAX-DOAS show a good agreement with OMI satellite observations with a Pearson correlation coefficient (R) of 0.95. In addition, measurements of the O3 vertical distribution indicate that the ozone productions do not only occur at surface level but also at higher altitudes (about 1.1 km). Planetary boundary layer (PBL) height and horizontal and vertical wind field information were integrated to discuss the ozone formation at upper altitudes. The results reveal that enhanced ozone concentrations at ground level and upper altitudes are not directly related to horizontal and vertical transportation. Similar patterns of O3 and HCHO vertical distributions were observed during this campaign, which implies that the ozone productions near the surface and at higher altitudes are mainly influenced by the abundance of volatile organic compounds (VOCs) in the lower troposphere.