In experimental measurements of the bit-error rate for a laser communication system, we show improved performance with the implementation of low-order (tip/tilt) adaptive optics in a free-space link. With simulated atmospheric tilt injected by a conventional piezoelectric tilt mirror, an adaptive optics system with a Xinetics tilt mirror was used in a closed loop. The laboratory experiment replicated a monostatic propagation with a cooperative wave front beacon at the receiver. Owing to constraints in the speed of the processing hardware, the data is scaled to represent an actual propagation of a few kilometers under moderate scintillation conditions. We compare the experimental data and indirect measurement of the bit-error rate before correction and after correction, with a theoretical prediction.
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http://dx.doi.org/10.1364/ao.42.004239 | DOI Listing |
Asian J Transfus Sci
September 2022
Department of Physiology, Mahatma Gandhi Medical College, Sri Balaji Vidyapeeth (Deemed to be University), Puducherry, India.
Vasovagal syncope (VVS) in donors is a transient loss of consciousness due to short-term global cerebral hypoperfusion, which has a rapid onset and has complete spontaneous recovery. VVS may be triggered by pain, fear, anxiety, or emotional upset and loss of blood perse. It is an exaggeration of an adaptive response meant to assist in reducing the amount of bleeding/loss of blood.
View Article and Find Full Text PDFAlzheimers Dement (Amst)
January 2025
Introduction: We explored associations between measurements of the ocular choroid microvasculature and Alzheimer's disease (AD) risk.
Methods: We measured the choroidal vasculature appearing in optical coherence tomography (OCT) scans of 69 healthy, mid-life individuals in the PREVENT Dementia cohort. The cohort was prospectively split into low-, medium-, and high-risk groups based on the presence of known risk factors (apolipoprotein E [] ε4 genotype and family history of dementia [FH]).
Anal Bioanal Chem
January 2025
Turkish Petroleum Refineries Co. TÜPRAŞ R&D Center, Körfez, Kocaeli, 41790, Türkiye.
Monoelemental calibration solutions are the most common reference in elemental analysis, linking measurement results to the International System of Units (SI). National Metrology Institutes (NMI) prepare these solutions as certified reference materials (CRM) and determine their elemental mass fraction with high accuracy. Characterization with high accuracy is one of the most critical steps in CRM production.
View Article and Find Full Text PDFEye (Lond)
January 2025
Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
Purpose: To determine how Hardy-Rand-Rittler (HRR) colour vision testing correlates with visual functional and structural assessments in Cone and Cone-Rod Dystrophy.
Methods: Thirty-four Cone and 69 Cone-Rod Dystrophy patients diagnosed by electroretinography (ERG) at the Save Sight Institute in Sydney were included in a retrospective analysis. Each patient's HRR colour vision test scores were compared with markers of cone and rod system function including visual acuity (VA), ERG responses, changes on Spectral Domain Optical Coherence Tomography (OCT) and Fundus Autofluorescence.
PLoS One
January 2025
Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States of America.
Traumatic optic neuropathy (TON) is a common cause of irreversible blindness following head injury. TON is characterized by axon damage in the optic nerve followed by retinal ganglion cell death in the days and weeks following injury. At present, no therapeutic or surgical approach has been found to offer any benefit beyond observation alone.
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