In this paper, we experimentally evaluated the performance of underwater optical communications using 1 Mbit/s on-off keying signals of perfect optical vortices. Perfect optical vortices generated by Fourier transformation of the Bessel-Gaussian beam are propagated through a 2.6 m underwater medium and affected by various water conditions such as stagnant water, water flow, temperature difference, and air bubbles, so beam wander and fluctuation of the signal are studied. Air bubbles have the maximum effect on signal fluctuations and beam wanders. Measurement of the system bit error rate (BER) based on the signal-to-noise ratio (SNR) for these situations matches the results of wandering and fluctuations. The system BER is studied for different values of SNR, and its value is more degraded due to the air bubbles.
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http://dx.doi.org/10.1364/AO.57.009148 | DOI Listing |
Trends Hear
January 2025
Faculty of Medicine and University Hospital Cologne, Department of Otorhinolaryngology, Head and Neck Surgery, University of Cologne, Cologne, Germany.
Speech-on-speech masking is a common and challenging situation in everyday verbal communication. The ability to segregate competing auditory streams is a necessary requirement for focusing attention on the target speech. The Visual World Paradigm (VWP) provides insight into speech processing by capturing gaze fixations on visually presented icons that reflect the speech signal.
View Article and Find Full Text PDFNeurocrit Care
January 2025
Department of Health Research, Medical Technology, SINTEF, Trondheim, Norway.
Background: Optic nerve sheath diameter (ONSD) is a promising noninvasive parameter for intracranial pressure (ICP) assessment. However, in the setting of aneurysmal subarachnoid hemorrhage (aSAH), several previous studies have reported no association between ultrasonically measured ONSD and ICP. In this study, we evaluate ONSD in patients with aSAH using a novel method of automated real-time ultrasonographic measurements and explore whether factors such as having undergone surgery affects its association to ICP.
View Article and Find Full Text PDFJ Anaesthesiol Clin Pharmacol
August 2024
Department of Anesthesia and Critical Care, Pt. B. D. Sharma PGIMS, Rohtak, Haryana, India.
Background: Traditionally, the sniffing position has been considered a standard head and neck position during direct laryngoscopy. The perfect head and neck position for video laryngoscopy has yet not been described. Hence, we planned the present study to compare the neutral and sniffing position for ease of intubation using Airtraq.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2025
College of Materials Science and Engineering, Nanjing Forestry University, Nanjing, 210037, China.
Since its discovery, carbon quantum dots (CDs) have been widely applied in cell imaging, drug delivery, biosensing, and photocatalysis due to their excellent water solubility, chemical stability, fluorescence stability biocompatibility, low toxicity, and preparation cost. However, the low fluorescence yield and poor surface structure limit the application of CDs. Heteroatom doping is considered an ideal method to improve CDs' optical and electrical properties.
View Article and Find Full Text PDFnpj Quantum Inf
December 2024
ETH Zurich, Department of Physics, Institute for Quantum Electronics, Optical Nanomaterial Group, Auguste-Piccard-Hof, 1, 8093 Zurich, Switzerland.
Optical quantum communication technologies are making the prospect of unconditionally secure and efficient information transfer a reality. The possibility of generating and reliably detecting quantum states of light, with the further need of increasing the private data-rate is where most research efforts are focusing. The physical concept of entanglement is a solution guaranteeing the highest degree of security in device-independent schemes, yet its implementation and preservation over long communication links is hard to achieve.
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