Search Results (2,872)

This paper presents a novel design approach for mitigating the adverse effects of antenna mountings on the radiation pattern of GNSS antennas. By employing a resistive structure integrated into the ground plane, the proposed solution suppresses unwanted edge diffraction and near-field reflections caused by nearby mounting hardware. The design is developed using the concept of tapered resistive sheets and optimized using a customized cost function that accounts for pattern degradation across multiple realistic mounting configurations, ensuring robust performance under varying installation conditions. The resulting structure is fabricated using additive manufacturing (AM), enabling precise realization of complex resistive profiles with tailored surface impedance. Comprehensive validation through both electromagnetic simulations and experimental measurements demonstrates significant improvements in radiation pattern stability and reduced sensitivity to near-field objects, particularly in critical GNSS bands such as E5a/L5 and E1/L1. The results demonstrate that the proposed structure significantly enhances antenna reliability and calibration integrity in real-world deployments, offering a practical, hardware-based solution to a persistent challenge in high-precision GNSS systems. Full article

Background/Objectives: Although the Spinal Instability Neoplastic Score (SINS) is widely used to estimate spinal metastases fracture risk and guide decisions on stabilisation procedures, prior studies have demonstrated mixed results. Patients with the same score exhibit clinically heterogeneous outcomes, with some SINS criteria correlating less well with the estimated fracture risk than others. There are also barriers to implementation such as the time burden required for manual calculation and interobserver variability associated with qualitative morphological criteria. SINS also lacks sensitivity for detecting latent structural compromise in treatment-naive patients and those susceptible to the iatrogenic effects of stereotactic body radiation therapy. This review aims to evaluate emerging imaging, biomechanical, and microstructural markers with the potential to improve fracture risk stratification and prognostication for spinal oncology patients. Methods: We synthesise evidence across three innovative frontiers: (1) biomechanical modelling, including CT-derived finite element analysis and failure-load pattern models; (2) radiomics, utilizing radiomics features from radiological imaging to develop a predictive model; and (3) microstructural MRI biomarkers, exploring the translatability of the Vertebral Bone Quality score, fat fraction, and paraspinal muscle atrophy from osteoporosis to the metastatic spine. Results: Emerging biomechanical, radiomic and microstructural imaging markers show potential in addressing some limitations of traditional SINS criteria for fracture risk stratification across the spinal oncology treatment continuum, from initial diagnosis to post-radiation surveillance, thereby facilitating more precise risk assessment. However, current evidence remains largely retrospective and heterogeneous, and further validation is required before clinical adoption. Conclusions: We propose a framework that shifts the paradigm from conventional morphological scoring toward a multiparametric assessment of spinal stability. Full article

Aerosols emitted by biomass burning represent one of the largest sources of uncertainty in our current understanding of the Earth’s radiative balance. We investigate the climatic influence of biomass burning aerosols emitted from six key regions of biomass burning by using GEOS-Chem coupled with the rapid radiative transfer model. We evaluate our model using AERONET observation, with the model reproducing data with 87% observed spatial and seasonal variability with a low negative bias of 7%. The radiation sensitivity is generally highest for North Asia (NAS) and for North America (NCC); lowest for South America (SAM) and South and Southeast Asia (SSA); and moderate for Africa (AFR) and Oceania (OCE). These regional differences are related to the main burning types of the regions. When we consider the global radiation influence, AFR dominates the global picture due to the comparatively large biomass burned. We estimate the global mean radiation influence of biomass burning aerosol is −0.116 W m⁻². For monthly features, in summer, due to higher incident energy obtained in NAS and NCC, high negative radiation sensitivity of biomass burning, biomass burning aerosols, and biomass burning organic aerosol are shown in these regions. Meanwhile, the radiation sensitivity peak of black carbon for these two regions occurs earlier in late spring (NAS) or early summer (NCC), when large incident energy and large high reflectance snow cover coexist in these two high-latitude regions. A significant yearly difference in radiation influence, rather than radiation sensitivity, is found, with the relative difference between the maximum year and minimum year reaching 90% of the maximum radiation influence year. Specifically, two regions affected by El Niño (OCE and SSA) have the most significant yearly variation in all factors, with anomalies occurring in El Niño years. Full article

Currently, there is a trend in the energy sector towards the application of edge computing techniques to facilitate active monitoring of distribution networks. The adoption of this technique is crucial for applications involving distributed monitoring systems that require real-time data processing with low latency. An edge computing environment ensures an adequate response to two time-level response requirements. One for events that could trigger a serious problem in the distribution network, and a less demanding one for the management of energy. This article justifies and analyzes an architecture specifically designed to provide an adequate response to the two levels of time demand that set the procedure followed for the monitoring, storage and local diagnosis of several photovoltaic plants located on the same distribution network, with the aim of studying their joint production. One of the main contributions is related to the expansion of the capabilities of Phasor Measurement Units (PMUs) to monitor solar radiation or energy production perimeters by sector. The second major contribution is to guarantee the quality of the measurements and low latency in communications, using as a reference the IEEE C37.118-2011 synchrophasor standard in cooperation with the Time Sensitive Networking (TSN) synchronization protocol that guarantees simultaneity in distributed measurements. In short, a procedure is sought that allows a real-time response with the use of computing techniques very close to the origin of the measurements, guaranteeing exhaustive control from the moment the capture begins until the parameters are stored in a time series database. Full article

Xizang is characterized by high altitude, low air pressure, strong atmospheric transparency, and complex terrain, while sparse ground stations coexist with continuously available remotely sensed data, and systematic studies on SSR bias correction and meteorological influences under plateau conditions remain limited. This study focuses on a short-term spring case at one urban observation site in Lhasa, using observations collected from 4 to 30 April 2025 to investigate the bias correction of remotely sensed surface solar radiation (SSR) and the influence of meteorological factors. Ground observations and Himawari-8 remotely sensed data were first spatially and temporally matched and preprocessed. Spearman correlation analysis was then used to select key input variables. Support vector regression, random forest, XGBoost, and multiple linear regression models were subsequently developed, followed by a Stacking ensemble model for bias correction. Finally, local sensitivity analysis was conducted to examine the local response of the correction model to selected meteorological variables at a representative baseline point. The results showed that the correlation coefficient between remotely sensed SSR and ground-observed SSR was 0.88 ($p<0.001$). The Stacking ensemble model achieved the best performance, with a test set $R^2$ of 0.8796, an MAE of 118.54 W/m², and an RMSE of 152.41 W/m². Local sensitivity analysis showed that a +10 hPa perturbation in air pressure increased the model output by 173.45 W/m², while a +10 °C perturbation in air temperature increased the output by 23.76 W/m². This study provides a reference for improving the accuracy of remotely sensed SSR and for solar resource assessment in plateau regions. Full article

Background/Objectives: Pancreatic ductal adenocarcinomas (PDACs) are lethal tumors exhibiting resistance to most cancer therapeutics, particularly DNA-damaging agents. The KRAS oncogene drives PDACs, and many of these tumors are addicted to it and its downstream effectors. One such effector is Rac1, a small GTPase involved in actin cytoskeleton remodeling and regulation of the DNA damage response. We previously showed that Rac1 inhibition blocks activation of ATM/Chk2 and ATR/Chk1 pathways in response to gamma rays, sensitizing PDAC cells to radiation. Methods: Western blot analyses were used to assess the impacts of Rac1 inhibition on the components of the ATR/Chk1 cascade. Results: Here, we show that Rac1 inhibition disrupts ATR/Chk1 signaling by promoting degradation of Claspin, a key component of the fork protection complex needed for the Ser345-phosphorylation of Chk1 by ATR. In PDACs and normal pancreatic ductal cells, Rac1 inhibition (via inhibitors or siRNA) decreased Claspin protein levels without affecting its mRNA, reflecting a >3-fold reduction in Claspin’s half-life. Claspin contains a phosphodegron recognized by SCF^βTrCP E3 ubiquitin ligase when phosphorylated at Ser30/Ser34, a process involving PLK1 kinase. In PDAC cells, Claspin degradation upon Rac1 inhibition required the proteasome and βTrCP1/2 proteins, and was blocked by the mutagenesis of Ser30/Ser34, but occurred independently of PLK1 activity. Although Rac1 inhibitors reduced Claspin in both normal and cancer cells, PDAC cells may be uniquely vulnerable due to elevated replication stress and greater reliance on ATR/Chk1. Accordingly, Claspin depletion sensitized PDAC cells but not normal cells to gamma rays, inducing apoptosis only in cancer cells. Conclusions: These findings identify Rac1 as a critical regulator of ATR/Chk1 signaling through stabilization of the fork protection protein Claspin. Rac1 inhibition promotes the βTrCP-dependent, proteasome-mediated degradation of Claspin via its phosphodegron, thereby impairing Chk1 activation in response to DNA damage. Full article

Polylactic acid (PLA) is a promising biopolymer for environmentally friendly coating development. However, its UV radiation resistance has not yet been sufficiently studied, particularly in formulations containing plasticizers or fillers. In this study, a series of samples were prepared: pure PLA films, PLA films with plasticizers, filled composites, and films obtained from aqueous PLA dispersions. The samples were tested for UV resistance and characterized using FTIR spectroscopy, surface energy analysis, and topography. The results showed that UV irradiation of pure PLA caused carbonyl band broadening and a shift toward lower wavenumbers, water contact angle decrease and surface energy polar component increase. The effect of plasticizers was chemical composition-dependent; epoxy linoleic acid increased the degradation rate, whereas PEG-400 and menthol oleic acid reduced the carbonyl groups accumulation. Menthol oleic acid demonstrated the strongest stabilizing effect. The calcite and kaolin fillers promoted surface oxidation and hydrophilization, while coffee grounds biochar reduced the degradation rate. Films obtained from aqueous dispersions were the most sensitive to UV aging, as residual emulsifier significantly enhanced surface hydrophilization. Full article

Coral mucus serves as a crucial defensive barrier for corals, where the mucus microbes play a vital role in the coral’s resistance to external stresses. However, detailed knowledge of the effect of UV radiation on coral mucus microbiome is limited, particularly regarding the UV resistance mechanisms of coral mucus microbes. This study investigates changes in the mucus microbial community and possible UV-resistant mechanisms of the mucus microbiota of Porites sp. and Favites sp. under UV stress using high-throughput sequencing, UV-resistant microbial isolation, and RT-qPCR analysis. Compared to the control, UV stress alters microbial community structure by reducing microbial diversity, e.g., the relative abundance of Aquibacter, Agaribacter, and Oleibacter in coral Porites sp., and the Roseobacter clade CHAB_I_5 lineage, Roseivirga, and Nautella in coral Favites sp. increase under UV stress. Meanwhile, it is indicated that the Favites sp. mucus microbiome is much more sensitive than the Porites sp. mucus microbiome. A total of 428 microbial strains belonging to 5 phyla, 7 classes, 15 orders, 23 families, and 47 genera were isolated from these two coral mucus species, with Ruegeria and Rossellomorea as the most abundant cultured taxa. Pseudoalteromonas galatheae strain P12 and Limimaricola pyoseonensis strains P2 and P9 have been proven to exhibit higher UV resistance by enhanced expression of tyr, sod, gogat, and uvrC genes, indicating that the UV resistance of coral mucus bacteria involves complex molecular processes, including upregulation of antioxidant enzyme expression and enhancement of melanin and glutamic acid biosynthesis. These findings enhance our understanding of coral mucus microbial ecological functions, particularly highlighting the coral mucus microbial UV resistance strategy. Full article

In this work, we discuss the impact of polarized scene radiances on the intercalibration of CPF and VIIRS reflective solar bands and the mitigation of these effects using empirical Polarization Distribution Models (ePDMs). The ePDMs, derived from multidirectional polarized reflectance measurements taken by the POLDER instrument, can provide the polarization state of the reflected solar radiation in terms of the Degree and Angle of Polarization, DOP and AOP, for each spatially, temporally, and angularly matched intercalibration footprint between CPF and VIIRS. The CPF science team will leverage these ePDMs to identify scenes with low polarization to reduce intercalibration uncertainties for specific VIIRS channels that are polarization-sensitive. The study also demonstrates that, in the absence of ePDM-based filtering of intercalibration samples, polarization-induced biases in VIIRS reflectance measurements for shortwave bands (e.g., M3 0.49 μm) can be as high as 2.4% for clear-sky over ocean scenes. Full article

Climate change is expected to increase the frequency and severity of drought events in Europe, necessitating the identification of more water-efficient cropping systems. This study compared the evapotranspiration dynamics, water-use efficiency, and yield performance of maize (Zea mays L.) and grain sorghum (Sorghum bicolor L. Moench) under controlled field conditions using a Thornthwaite–Mather-type compensation evapotranspirometer. Three water regimes (100%, 50%, and 30% of optimal water supply) were applied during the reproductive stage, combined with weed-free and weed-infested treatments. Under moderate water deficit (50% water supply), grain sorghum maintained stable grain yield, while maize grain yield decreased by 17.98%. Under severe water deficit (30% water supply), grain yield reductions reached 36.04% in maize and 42.80% in sorghum. Grain sorghum consistently required less water and used 2.87–38.17% less water to produce 1 kg of grain compared to maize across treatments. Weed interference was associated with a lower yield and water-use efficiency in both species, while severe water deficit (70%) caused substantial declines in all measured parameters. Evapotranspiration was primarily driven by solar radiation and temperature, with reduced sensitivity under increasing water limitation. Overall, the results suggest that grain sorghum may represent a viable alternative to maize under moderate drought conditions; however, both crops require supplemental irrigation under severe water scarcity. The study highlights the importance of integrated weed management and provides novel insights into crop water-use dynamics under combined abiotic and biotic stress conditions. Full article

Acute hypoxemic respiratory failure (AHRF) represents one of the most common and clinically challenging indications for invasive mechanical ventilation in the intensive care unit, characterized by profound etiological heterogeneity that demands accurate diagnosis to guide treatment. While clinical history, physical examination, and laboratory data remain essential, they are often insufficient to reliably discriminate among conditions such as acute respiratory distress syndrome (ARDS), cardiogenic pulmonary edema, and pneumonia—particularly in mechanically ventilated patients. Lung imaging has therefore emerged as an indispensable complement to clinical assessment. In this narrative review, we systematically describe the physical principles, clinical applications, and limitations of the imaging modalities currently available in critical care: chest X-ray (CXR), computed tomography (CT), lung ultrasound (LUS), electrical impedance tomography (EIT), and positron emission tomography (PET). CXR remains the most widely used bedside tool but is constrained by low sensitivity and significant interobserver variability. CT is the gold standard for morphological and quantitative lung phenotyping, enabling the assessment of recruitability, baby lung characterization, and the identification of complications, but requires patient transport and exposes patients to ionizing radiation. LUS offers real-time, bedside evaluation of aeration with high diagnostic accuracy for pneumothorax and pleural effusion, and is increasingly integrated into revised ARDS diagnostic criteria. EIT enables continuous, radiation-free monitoring of regional ventilation distribution and positive end-expiratory pressure (PEEP)-guided titration directly at the bedside. While PET provides unparalleled quantification of regional inflammation and ventilation-perfusion mismatch, it currently remains a purely investigative research tool. Finally, we discuss emerging technological and AI-driven advances—including dual-energy CT, next-generation EIT, and deep learning algorithms—that are poised to transform lung imaging from a passive diagnostic tool into an active, personalized guide to respiratory management. Full article

The dryline is a sharp boundary between moist air from the Gulf of Mexico and dry air from the desert Southwest. In West Texas, this boundary often surges east during the day and retreats west at night. Understanding exactly why it moves back and forth is critical for predicting where severe thunderstorms will form. Yet the physical drivers of dryline life cycle remain poorly understood and frequently under-predicted. This study utilizes a variable-resolution Model for Prediction Across Scales (MPAS) configuration (3–60 km) with the YSU non-local planetary boundary layer (PBL) scheme to investigate a representative dryline event from April 2017. The control simulation was validated against NWS Surface Analysis, demonstrating a high spatial correlation in both synoptic-scale pressure distributions and mesoscale moisture gradients, successfully resolving a nocturnal retrogression of approximately 170 km, with the dryline retreating from its peak afternoon surge at 100.7° W to a recovery point of 102.5° W between 0000 UTC and 0600 UTC 10 April. This recovery occurred at an average speed of 28.3 km/h, consistently constrained beneath a resilient capping inversion. To decouple the environmental drivers of this motion, two targeted sensitivity experiments were conducted: (1) Mechanical Forcing: A 50% reduction in regional topography confirms that the West Texas sloping ramp acts as a “topographic pump.” Without this gradient, the hydrostatic pressure falls were insufficient to drive the nocturnal retreat, causing the boundary to stall eastward. (2) Thermodynamic Regulation: A 50% reduction in soil moisture revealed an “energy swap,” the near-total partitioning of net radiation into sensible heat drove the planetary boundary layer to a higher peak value—a 600 m increase over the control simulation. These results provide a comprehensive physical framework for dryline mobility, demonstrating that while terrain plays an important role in the extent of the diurnal oscillation, soil moisture governs the vertical structure and moisture gradient intensity. Our findings suggest that high-resolution vertical layering and accurate land-surface initialization are prerequisites for capturing the inversion layer dynamics essential for dryline forecasting. However, these findings are based on a single event and require validation across a broader range of dryline cases. Full article

The Northern Tibetan Plateau is among the most climate-sensitive alpine regions globally. To address the limited applicability of the traditional Remote Sensing Ecological Index (RSEI) in sparsely vegetated areas, this study developed a Soil-Adjusted Remote Sensing Ecological Index (SRSEI) tailored to cold and arid environments. The ecological quality of the Northern Tibetan Plateau from 2000 to 2025 was systematically evaluated and analyzed. The results indicate that: (1) The improved SRSEI achieved a first principal component (PC1) contribution of 72.76%, a significant enhancement over traditional models that effectively mitigates noise from soil backgrounds and anthropogenic features. (2) Between 2000 and 2025, ecological quality was predominantly moderate, following a characterized east-to-west declining spatial gradient. Overall mean SRSEI values fluctuated between 0.420 and 0.476, exhibiting a marginal downward trend. (3) Ecological degradation affected 50.17% of the region, with 26.14% facing risks of sustained decline. Conversely, 40.11% of the area displayed potential recovery trends, suggesting potential spatial divergence in future ecological trajectories. (4) Regional ecological dynamics are governed by a topographic-thermal compound driving mechanism. Elevation (DEM), temperature (TEMP), and surface shortwave radiation (SRAD) emerged as the dominant explanatory variables. Furthermore, dual-factor interactions exhibited significant enhancement effects, while the influence of anthropogenic factors was comparatively weak at the regional scale. These findings provide a scientific basis for the long-term monitoring of fragile alpine ecosystems and the strategic development of the Qiangtang National Park. Full article

Background/Objectives: Cystic fibrosis is a chronic multisystem disease in which pulmonary involvement is the main determinant of morbidity and mortality. Chest computed tomography is the reference standard for assessing structural lung damage, but its repeated use is limited by cumulative radiation exposure. Lung ultrasound has emerged as a radiation-free alternative; however, its role in adult patients remains incompletely defined. This study aimed to evaluate the correlation between CT-derived structural lung damage and ultrasound findings, and to assess the complementary role of these imaging modalities. Methods: A prospective cohort study was conducted including adult patients with cystic fibrosis who underwent both chest computed tomography and lung ultrasound during the same clinical episode. Structural lung involvement was assessed using the Bhalla score, while lung aeration was evaluated using the Lung Ultrasound Score. Correlation analyses, severity stratification, regression modeling, and longitudinal comparisons were performed. Results: Thirteen patients contributed 24 imaging evaluations. A strong positive correlation between Bhalla score and ultrasound findings was observed in the cross-sectional analysis and remained consistent when all examinations were included. Ultrasound scores increased significantly across CT-defined severity groups, and regression analysis confirmed a significant association between the two methods. Exploratory analysis showed stronger associations for peripheral and aeration-related abnormalities, while weaker associations were observed for deeper airway changes. No significant correlation was identified in longitudinal analysis. Conclusions: Lung ultrasound correlates well with CT-derived structural lung damage and may serve as a complementary, radiation-free tool for disease assessment in adult cystic fibrosis. However, its limited sensitivity in detecting temporal changes highlights the continued importance of CT in selected clinical scenarios. Full article

Hydropower-dependent electricity systems, such as Ecuador’s, face critical supply disruptions during droughts: a vulnerability exemplified by the 2024 power outages. This study assesses the technical, economic and environmental feasibility of a 200.84 MWp grid-connected solar photovoltaic (PV) plant proposed for the Pacific Refinery site in Manabi, Ecuador, as a strategy to diversify the energy matrix and reduce hydrological risk. Using site-specific solar resource data (4.65 kWh/m²/day) and PVSyst simulations, the plant achieves an annual energy production of 295 GWh with a performance ratio (PR) of 85.3%. A discounted cash flow analysis over 25 years, assuming a 7% discount rate and an electricity price of 60 USD/MWh, yields a net present value (NPV) of 104.9 MUSD, an internal rate of return (IRR) of 62.2%, and a levelized cost of energy (LCOE) of 14.5 USD/MWh, well below current industrial tariffs in Ecuador. Sensitivity analysis confirms project viability under ±15% variations in investment cost, energy price, and solar resource. Over its lifetime, the plant avoids 1.83 Mt of CO₂ emissions, supporting national decarbonization goals. The results demonstrate that large-scale PV deployment in high-radiation, low-latitude regions can be highly profitable and contribute to energy sovereignty in hydropower-dependent systems. Furthermore, this study provides a replicable model for repurposing unused industrial land for renewable energy generation, offering actionable insights for policymakers and investors in developing economies. Full article