Satellites that navigate by talking to each other slowly lose their sense of direction, because nothing in a purely Earth-orbiting network provides a fixed reference in space.

With the continuous advancement of spaceborne synthetic aperture radar (SAR) technology, L-band SAR has come to play an increasingly important role in Earth observation; however, its imaging, interferometric, and polarimetric performance are susceptible to ionospheric disturbances. In equatorial nighttime data, amplitude streak artifacts induced by equatorial plasma bubbles frequently occur and have traditionally been regarded as interference factors in SAR imaging. Nevertheless, these artifacts essentially carry critical information on ionospheric irregularities and can be exploited to retrieve physical parameters such as scintillation intensity and turbulence spectral indices. Existing methods either rely on comparisons between disturbed and undisturbed images or are limited to preliminary one-dimensional parameter estimation along the track, making it difficult to achieve two-dimensional fine-scale retrieval of scintillation structures, and lacking systematic validation of their spatial correlation with equatorial ionospheric anomalies. Therefore, how to extract the two-dimensional spatial distribution of ionospheric scintillation parameters from amplitude streak artifacts and reveal their intrinsic relationship with regions of enhanced electron density has become an important scientific question in the field of ionospheric remote sensing.

Researchers report that intestinal neutral ceramidase promotes MASH by reshaping gut microbes and increasing 2-hydroxyhippuric acid, a metabolite that suppresses epithelial AhR signalling. In mouse models, deleting the enzyme in intestinal epithelial cells restored fucosylation, strengthened the gut barrier, reduced endotoxin translocation, and attenuated liver inflammation and fibrosis. The findings identify a microbiota–2-HHA–AhR–fucosylation axis that could guide barrier-restoring, microbiome-based therapies for MASH and related systemic inflammatory complications in future clinical translation and drug development programs.

With the advancement of deep-space missions such as crewed lunar exploration and Mars exploration, artificial intelligence (AI) technologies are being increasingly embedded into aerospace engineering management processes, and managers' AI competency has become a critical factor affecting mission delivery performance and safety compliance. However, traditional project management competency models have been primarily constructed around process control and redundancy design within deterministic systems, failing to explicitly address governance challenges introduced by AI integration—including black-box opacity, accountability allocation, traceable review of AI outputs, and accountability mechanisms for assisted decision-making. Although existing NASA and ESA frameworks provide fundamental support for aerospace project delivery, AI-related competencies in aerospace management exhibit inherent interdependencies. Managers are required to continuously balance delivery schedules and cost pressures against mission assurance obligations such as verification and validation, configuration control, and compliance, making it impossible to simply represent AI competency as a linear list of attributes. Therefore, how to construct an AI competency assessment framework that captures governance priorities and multi-attribute interdependencies has become a critical issue urgently to be addressed in aerospace engineering management in the AI era.

Precision nutrient management in high-density orchards is critical for yield and fruit quality, yet accurately gauging the nitrogen status of individual trees remains a challenge. 

Ultra-low-pass whole-genome sequencing of bile cell-free DNA may improve the evaluation of biliary strictures, particularly when initial pathology is inconclusive. In 95 patients, the approach detected tumour DNA with 96% specificity in initially indeterminate cases and anticipated conventional diagnosis by a median of 38 days. Copy-number profiles also helped distinguish cholangiocarcinoma from pancreatic ductal adenocarcinoma, while integration with targeted mutation burden identified a subgroup with significantly poorer overall survival, supporting prospective multicentre and independent validation.

A new study reports balloon-borne, in situ measurements of dust transport to the tropopause layer over the northern Qinghai-Tibet Plateau, offering a fresh observational perspective on a process that has mostly been inferred from remote sensing and models.