Search Results (10)

When performing nighttime passive visible remote sensing of non-emissive land surfaces, illumination is typically dominated by weak moonlight that varies with lunar phase, producing low-radiance images with degraded textures and thus motivating low-radiance visible remote sensing image enhancement. We propose a Complementary Illumination–Semantic Prompt Diffusion framework (CISPD) that incorporates a semantic-invariant prompt and a self-learned illumination-aware prompt to guide diffusion-based low-light remote sensing image enhancement. During denoising, we sequentially inject two complementary prompts. We first retrieve a self-learned illumination-aware prompt from a learnable pool conditioned on the current latent context to correct non-uniform brightness, and then apply a semantic-invariant prompt extracted from a vision foundation model to reinforce geometric structures and suppress artifacts. To keep the two prompts complementary rather than redundant, we introduce a contrastive constraint that encourages their representations to remain distinct, and the dual prompts jointly steer the diffusion trajectory toward well-exposed results with faithful structures. Experiments on iSAID-dark and darkrs, together with LOLv1 and LOLv2, demonstrate that CISPD achieves the best PSNR and SSIM on iSAID-dark, strong qualitative generalization on darkrs, and competitive quantitative performance on LOLv1 and LOLv2. Full article

Gamma-ray bursts (GRBs) are widely recognized to exhibit jet-like emission structures, though previous studies often assumed isotropic emission due to observational constraints. This assumption limited our understanding of the intrinsic properties of GRBs. Here, we analyze 40 GRBs with observed X-ray plateaus and jet features, all with measured redshifts. By applying jet corrections to prompt and plateau-phase quantities, we probe their intrinsic behavior. We find that the jet-corrected prompt emission energy ($E_{jet}$) depends less strongly on the jet-corrected X-ray luminosity at the end of the plateau ($L_{X,jet}$). An anti-correlation is also observed between the jet opening angle (${\theta }_{jet}$) and the rest frame peak energy ($E_{p,z}$): $E_{p,z}\propto {\theta }_{jet}^{-0.44\pm 0.13}$ for ISM and $E_{p,z}\propto {\theta }_{jet}^{-0.78\pm 0.13}$ for wind environments, indicating that more collimated jets yield higher peak energies. After jet correction, the $L_X$-$T_{a,z}$ correlation and the three-parameter $L_X$-$T_{a,z}$-$E_{\gamma ,iso}$, $L_X$-$T_{a,z}$-$L_p$ and $L_X$-$T_{a,z}$-$E_{p,z}$ relations are generally weakened. Among these, the first three remain relatively stable, suggesting they reflect intrinsic GRB physics, whereas the $L_X$-$T_{a,z}$-$E_{p,z}$ relation weakens significantly, implying it may be an artifact of the isotropic assumption. We also identify a new three-parameter correlation: ${\theta }_{jet}\left(ISM\right)\propto E_{jet}{\left(ISM\right)}^{0.36\pm 0.06}{E}_{p,z}^{-0.62\pm 0.09}$, ${\theta }_{jet}\left(Wind\right)\propto E_{jet}$${\left(Wind\right)}^{0.29\pm 0.09}$$E_{p,z}^{-0.61\pm 0.09}$. Full article

Greenhouse gas emissions are a major driver of global climate change, prompting increasing attention to the role of financial systems in supporting environmental sustainability. In this context, understanding how financial development influences emissions in emerging economies has become critically important. According to the findings of the long-term estimation, financial development has a direct negative impact on total greenhouse gas emissions and carbon dioxide emissions. Meanwhile, economic growth, trade openness, and population growth exert positive effects on these emissions. Although financial development negatively influences emissions, its interaction with economic growth and population dynamics is complex and may indirectly affect emissions through these factors. In addition, the error correction coefficient found for each country is negative and significant. The panel causality results indicate a unidirectional causal relationship between economic growth and total greenhouse gas emissions and carbon dioxide emissions. These findings are important for governments developing environmental policies, as they show how financial development can improve environmental impacts and help create sustainability-focused policies. Full article

The International Maritime Organization (IMO) mandates a reduction in carbon dioxide emissions from 2008 levels by at least 40% by 2030, prompting the widespread adoption of slow steaming and engine de-rating strategies. This study investigates the fatigue life of marine propulsion shafts under slow steaming conditions, focusing on the interplay between torsional and bending vibrations. A finite element (FE) model of a low-speed two-stroke propulsion system is developed, incorporating torsional and lateral excitation sources from both the engine and propeller. Vibrational stresses are computed for multiple operating conditions, and fatigue life is assessed using both the conventional Det Norske Veritas (DNV) methodology and a proposed biaxial stress approach. Results indicate that while torsional vibrations remain the primary fatigue driver, bending-induced stresses contribute marginally to the overall fatigue life. The proposed methodology refines high-cycle fatigue (HCF) assessment by incorporating a corrected S-N curve and equivalent von Mises stress criteria. Comparisons with classification society standards demonstrate that existing guidelines remain valid for most cases, though further studies on extreme alignment deviations and dynamic bending effects are recommended. This study enhances understanding of fatigue mechanisms in marine shafting and proposes a refined methodology for improved fatigue life prediction. Full article

Leveraging the photometric data of the Sloan Digital Sky Survey and the Galaxy Evolution Explorer (GALEX), we construct mean/median spectral energy distributions (SEDs) for unique bright quasars in redshift bins of 0.2 and up to $z\simeq 3$, after taking the GALEX non-detection into account. Further correcting for the absorption of the intergalactic medium, these mean/median quasar SEDs constitute a surprisingly redshift-independent mean/median composite SED from the rest-frame optical down to ≃$500 \mathring{\mathrm{A}}$ for quasars with bolometric luminosity brighter than ${10}^{45.5}\mathrm{erg}{\mathrm{s}}^{-1}$. Moreover, the mean/median composite quasar SED is plausibly also independent of black hole mass and Eddington ratio, and suggests similar properties of dust and gas in the quasar host galaxies since cosmic noon. Both the mean and median composite SEDs are nicely consistent with previous mean composite quasar spectra at wavelengths beyond ≃$1000 \mathring{\mathrm{A}}$, but at shorter wavelengths, are redder, indicating, on average, less ionizing radiation than previously expected. Through comparing the model-predicted to the observed composite quasar SEDs, we favor a simply truncated disk model, rather than a standard thin disk model, for the quasar central engine, though we request more sophisticated disk models. Future deep ultraviolet facilities, such as the China Space Station Telescope and the Ultraviolet Explorer, would prompt revolutions in many aspects, including the quasar central engine, production of the broad emission lines in quasars, and cosmic reionization. Full article

Climate change poses an unprecedented global challenge, which prompts nations to adopt new strategies to mitigate greenhouse gas emissions. The European Union emissions trading system (EU ETS) is a cornerstone of the EU’s efforts towards a cost-effective fight against climate change. This study examines the effectiveness of the EU ETS by analyzing monthly data from December 2008 to December 2021, with the focus on CO₂ emission allowance futures prices, renewable energy indices, coal prices, oil prices, and fossil energy indices. The key findings are as follows: The CO₂ emission allowance futures prices have averaged EUR 14.83 per ton, ranging from EUR 2.87 to EUR 76.81, which shows a significant upward trend. The renewable energy index also demonstrated strong growth, with a mean 1562.07 and maximum 4571.96. Coal prices have averaged EUR 65.32 per ton, while Brent oil prices averaged EUR 59.85 per barrel. A cointegration analysis revealed a long-run equilibrium relationship between these variables. The Vector Error Correction model (VECM) revealed significant negative responses to long-run equilibrium deviations of the renewable energy index (−0.0155) and oil prices (−0.0236), a significant negative short-run response of CO₂ prices to their own lagged values (−0.223), and a significant positive short-run effect of oil prices on the fossil energy index (0.254). These results suggest the EU ETS has created significant linkages between carbon, energy, and financial markets. The study concludes that while the EU ETS has made progress in motivating emissions reductions and promoting renewable energy, the system’s efficacy still needs improvement. Full article

Enamel, dentin and cementum apatite has a complex composition. The lack of complete reports on the chemical composition of all tooth tissues together and the need to create a modern biomaterial that reproduces the correct ratio of individual tooth mineral components prompted the authors to undertake the research. A detailed evaluation of the micro- and macro-elements of tooth powder, using various methods of chemical analysis was conducted. All four groups of human sound teeth were crushed using the grinder. A fine powder was implemented for the FTIR (Fourier Transform Infrared Spectroscopy), ICP (Inductively Coupled Plasma Optical Emission Spectometry) and for the potentiometric titration, SEM and mercury porosimetry analyses. The obtained studies indicate that there is no significant correlation in chemical composition between the different teeth types. This proves that every removed, crushed tooth free of microorganisms can be a suitable material for alveolar augmentation. It is essential to know the chemical profiles of different elements in teeth to develop a new class of biomaterials for clinical applications. Full article

Septic ankle arthritis is a devastating clinical entity with high risks of morbidity and mortality. Prompt treatment is necessary because delayed or inadequate treatment can lead to irreversible damage that may occur on the articular surface, resulting in cartilage erosion, infective synovitis, osteomyelitis, joint deformity, and pain and joint dysfunction. An aggressive surgical approach is required when a joint infection causes severe limb-threatening arthritis. A 58-year-old woman visited our clinic with increasing pain in the right ankle, which had been present for the previous 2 months. She complained of discomfort in daily life due to deformity of the ankle; limping; and severe pain in the ankle even after walking a little. The patient reported a history of right-ankle injury while exiting a bus in her early 20s. Plain radiographs of the right ankle joint revealed that the medial malleolus was nearly absent in the right ankle joint on the anteroposterior view, and severe varus deformity was observed with osteoarthritic changes because of joint space destruction. Magnetic resonance imaging revealed diffuse synovial thickening of the destroyed tibiotalar joint with joint effusion. Hybrid 99mTc white blood cell single-photon emission computed tomography/computed tomography showed increased uptake along the soft tissue around the ankle joint; uptake was generally low in the talocrural and subtalar joints. A two-stage operation was performed to remove the infected lesions and correct the deformity, thus enabling limb salvage. The patient was nearly asymptomatic at the 6-month follow-up, with no discomfort in her daily life and nearly normal ability to carry out full functional activities. She had no complications or recurrent symptoms at the 1-year follow-up. We have described a rare case of a staged limb salvage procedure in a patient with chronic septic arthritis sequelae. For patients with severe joint deformity because of septic ankle sequelae, staged arthrodesis is a reliable method to remove infected lesions, solve soft tissue problems, correct deformities, and maintain leg length. Full article

Gamma-ray Bursts (GRBs) are highly energetic events that can be observed at extremely high redshift. However, inherent bias in GRB data due to selection effects and redshift evolution can significantly skew any subsequent analysis. We correct for important variables related to the GRB emission, such as the burst duration, $T_{90}^{*}$, the prompt isotropic energy, $E_{\mathrm{iso}}$, the rest-frame end time of the plateau emission, $T_{\mathrm{a},\mathrm{radio}}^{*}$, and its correspondent luminosity $L_{\mathrm{a},\mathrm{radio}}$, for radio afterglow. In particular, we use the Efron–Petrosian method presented in 1992 for the correction of our variables of interest. Specifically, we correct $E_{\mathrm{iso}}$ and $T_{90}^{*}$ for 80 GRBs, and $L_{\mathrm{a},\mathrm{radio}}$ and $T_{\mathrm{a},\mathrm{radio}}^{*}$ for a subsample of 18 GRBs that present a plateau-like flattening in their light curve. Upon application of this method, we find strong evolution with redshift in most variables, particularly in $L_{\mathrm{a},\mathrm{radio}}$, with values similar to those found in past and current literature in radio, X-ray and optical wavelengths, indicating that these variables are susceptible to observational bias. This analysis emphasizes the necessity of correcting observational data for evolutionary effects to obtain the intrinsic behavior of correlations to use them as discriminators among the most plausible theoretical models and as reliable cosmological tools. Full article

¹⁸F-FDG Positron Emission Tomography (PET) is used to monitor tumor response to ¹³¹I-therapy, but is confounded by prompt emissions (284, 364, 637, and 723 keV) from ¹³¹I, particularly in animal PET imaging. We propose a method for correcting this emission in ¹⁸F-FDG PET. The ¹³¹I prompt emission effect was assessed within various energy windows and various activities. We applied a single gamma correction method to a phantom and in vivo mouse model. The ¹³¹I prompt emission fraction was 12% when 300 µCi of ¹³¹I and 100 µCi of FDG were administered, and increased exponentially with escalating ¹³¹I activity for all energy windows. The difference in spill-over ratio was reduced to <5% after ¹³¹I prompt emission correction. In the mouse model, the standard uptake value (SUV) did not differ significantly between FDG PET only (gold standard) and FDG PET after ¹³¹I prompt emission-correction, whereas it was overestimated by 38% before correction. Contrast was improved by 18% after ¹³¹I prompt emission correction. We first found that count contamination on ¹⁸F-FDG follow-up scans due to ¹³¹I spilled-over count after ¹³¹I rituximab tumor targeted therapy. Our developed ¹³¹I prompt emission-correction method increased accuracy during measurement of standard uptake values on ¹⁸F-FDG PET. Full article