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In this article, we report the application of a commercial supercontinuum light source for testing fiber optics components in a broad optical range. We demonstrate that this kind of light can be successfully used to measure the parameters of a number of passive fiber components, such as fiber Bragg gratings, fiber couplers, wavelength division multiplexers, and fibered isolators. We also show that near the double wavelength of the pulsed laser used to pump the nonlinear fiber generating the supercontinuum, the standard optical spectrum analyzers demonstrate the false spectral peak that affects the test results and that using a simple low-cost monochromator placed at the supercontinuum source output permits the elimination of this peak. The results of experiments related to the characterization of passive fiber devices in the broad optical range, from 1 μm to more than 2 μm, are discussed in detail as possible applications of the proposed technique.

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In this paper, we present the results of an experimental study on the characterization of holmium-doped silica fiber. A standard acousto-optic modulator controls the output power of the ytterbium-doped fiber laser operating at 1134.5 nm and serving as a pump source of the holmium-doped fiber under test. This technique allows us to measure the lifetimes of 5I7 and 5I8 energy levels of Ho3+ ions. The effects of the fiber length and the concentration-dependent pair-induced quenching on the accuracy of the fluorescence lifetime measurement are considered. The results of this study are compared with those obtained using the exponential and Förster decay functions used for such types of measurements. It is demonstrated that the knowledge of two fiber parameters, the pump saturation power and the fluorescence saturation power, together with the fiber absorption spectrum, permits one to obtain the absorption cross-sections at the pump and other key wavelengths, the effective concentration of the active ions, and the quantum efficiency of the fluorescence from the laser level. The results of this study are applicable to the reliable characterization of any type of heavily doped gain fibers and to the further numerical modeling and optimization of fiber lasers. [ABSTRACT FROM AUTHOR]

Global warming is a worldwide and protracted phenomenon with heterogeneous local economic effects. We propose a dynamic economic assessment model of the world economy with high spatial resolution to assess its consequences. Our model features several forms of adaptation to local temperature changes, including costly trade and migration, local technological innovations, and local natality rates. We quantify the model at a 1 ∘ × 1 ∘ resolution and estimate damage functions that determine the impact of temperature changes on a region's fundamental productivity and amenities conditional on local temperatures. Welfare losses from global warming are very heterogeneous across locations, with 20% losses in parts of Africa and Latin America but also gains in some northern latitudes. Overall, spatial inequality increases. Uncertainty about average welfare effects is significant but much smaller for relative losses across space. Migration and innovation are shown to be important adaptation mechanisms. We use the model to study the impact of carbon taxes, abatement technologies, and clean energy subsidies. Carbon taxes delay consumption of fossil fuels and help flatten the temperature curve but are much more effective when an abatement technology is forthcoming. [ABSTRACT FROM AUTHOR]

Background: Chronic kidney disease (CKD) is characterized by decreased renal function. Detecting and treating CKD in its early stages is essential for prognosis and use of less invasive renal treatments. CKD can manifest with different markers of renal damage. However, few studies evaluate the presence of erythrocyte morphological changes in the peripheral blood of patients with CKD., Objective: To evaluate the correlation between erythrocyte morphological changes and KDIGO stage as a predictor of the severity of renal damage., Material and Methods: A descriptive, prospective, cross-sectional, and correlational study of patients admitted between March and April 2023. Qualitative variables were reported as frequencies and percentages, and quantitative variables were reported by central tendency and dispersion measures. Finally, Spearman correlation was performed between erythrocyte morphological alterations and the KDIGO stage in patients with CKD., Results: A total of 385 patients were included, and the correlation of the number of erythrocyte morphological alterations with the KDIGO stage showed that it is directly proportional in a significant way (Spearman's ρ 0.489, p < 0.0001). It was higher for anisocytosis., Conclusions: Erythrocyte morphological alterations in patients with CKD are frequent and could be a predictor of the severity of this disease., (Licencia CC 4.0 (BY-NC-ND) © 2024 Revista Médica del Instituto Mexicano del Seguro Social.)

Background: The prognosis of patients with ST-segment elevation myocardial infarction (STEMI) and previous percutaneous coronary intervention (PCI) is uncertain., Objective: To evaluate if previous PCI in patients with STEMI increases the risk of major cardiovascular events, and if final epicardial blood flow differs according to the reperfusion strategy., Material and Methods: Observational, longitudinal, comparative sub-study of the PHASE-MX trial that included patients with STEMI and reperfusion within 12 hours of symptom onset, who were classified according to their history of PCI. The occurrence of the composite primary endpoint (cardiovascular death, re-infarction, congestive heart failure and cardiogenic shock) within 30 days was evaluated using Kaplan-Meier estimates, log-rank test and Cox proportional hazards model. Epicardial blood flow was assessed using the TIMI grading system after reperfusion., Results: A total of 935 patients were included; 85.6% were males and 6.9% had a history of PCI; 53% underwent pharmacoinvasive therapy, and 47%, primary PCI. The incidence of the composite primary endpoint at 30 days in patients with a history of PCI was 9.8% vs 13.3% in those with no previous PCI (p = 0.06). Among the patients with previous PCI, 87.1% reached a final TIMI grade 3 flow after primary PCI vs. 75% in the group with pharmacoinvasive strategy (p = 0.235)., Conclusions: A history of PCI does not increase the risk of major cardiovascular events at 30 days; however, it impacted negatively on the final angiographic blood flow of patients that received pharmacoinvasive therapy (compared to primary PCI)., (Copyright: © 2024 Permanyer.)