Photonic radars are increasingly being developed and offer a promising replacement for traditional RF radars. They feature higher precision, and smaller size compared to the current microwave radars. One important part of a moving target indicating (MTI) radar is the Doppler shift measurement used to measure the radial velocity of a moving target.
View Article and Find Full Text PDFIn ischemic tissue, platelets can modulate angiogenesis. The specific factors influencing this function, however, are poorly understood. Here, we characterized the complement anaphylatoxin C5a-mediated activation of C5a receptor 1 (C5aR1) expressed on platelets as a potent regulator of ischemia-driven revascularization.
View Article and Find Full Text PDFBackground: Digital storytelling (DST), which combines traditional storytelling with digital tools, can provide a narrative pedagogy that promotes critical thinking (CT). However, we found no previous study in medical education.
Materials And Methods: The aim of the study was to investigate if DST can promote CT and, if so, which CT skills were improved.
Introduction: Storytelling is one of the earliest ways to share scientific advancements and discoveries. The advent of technology has updated this ancient art into a digitalized form. The boundaries between the digital storytelling (DST), and other types of videos are unclear.
View Article and Find Full Text PDFBackground: Flowering is a crucial stage during plant development. Plants may respond to unfavorable conditions by accelerating reproductive processes like flowering. In a recent study, we showed that PRECOCIOUS1 (POCO1) is a mitochondrial pentatricopeptide repeat (PPR) protein involved in flowering time and abscisic acid (ABA) signaling in Arabidopsis thaliana.
View Article and Find Full Text PDFFlowering is a vital developmental shift in plants from vegetative to reproductive phase. The timing of this shift is regulated by various linked genetic pathways including environmental cues and internal regulation. Here we report a role for an Arabidopsis gene, AT1G15480, which encodes a P-class pentatricopeptide repeat (PPR) protein, affecting flowering time.
View Article and Find Full Text PDFThis publisher's note amends the author listing in Opt. Lett.43, 2233 (2018).
View Article and Find Full Text PDFA microwave photonics instantaneous frequency measurement receiver was conceived and practically demonstrated. The system is based on phase modulation inside a Sagnac loop and therefore needs no bias voltage, resulting in no DC bias drifts. The system provides a DC output whose amplitude is a function of input signal frequency, and thus no high-frequency photo-detector is required.
View Article and Find Full Text PDFBackground: Students' perceptions of the educational environment are an important construct in assessing and enhancing the quality of medical training programs. Reliable and valid measurement, however, can be problematic - especially as instruments developed and tested in one culture are translated for use in another.
Materials And Method: This study sought to explore the psychometric properties of the Postgraduate Hospital Educational Environment Measure (PHEEM) for use in an Iranian hospital training setting.
J Opt Soc Am A Opt Image Sci Vis
June 2014
A microwave photonic in-phase and quadrature detector is conceived and practically demonstrated. The detector has the ability to become electronically reconfigured to operate at any frequency over a wide range. This makes it an excellent candidate for frequency agile radars and other electronic warfare systems based on frequency hopping.
View Article and Find Full Text PDFA microwave photonics phase detector is conceived and practically demonstrated. The phase-detector system employs a semiconductor optical amplifier as a four-wave mixer to enable phase detection over a broad frequency range. The system behavior is first mathematically modeled and then demonstrated practically.
View Article and Find Full Text PDFA photonic approach to instantaneously identify frequency components of microwave signals with multiple tones is conceived and practically demonstrated. A mathematical model was first developed to predict the behavior of the system. Then the system operation was tested in practice.
View Article and Find Full Text PDFA photonic radar warning receiver was conceived and practically demonstrated. The system was very flexible in terms of frequency measurement range and resolution. This was achieved using a cascaded grating which provided different time delays for different wavelengths.
View Article and Find Full Text PDFA broadband photonic instantaneous frequency measurement system utilizing four-wave mixing in highly nonlinear fiber is demonstrated. This new approach is highly stable and does not require any high-speed electronics or photodetectors. A first principles model accurately predicts the system response.
View Article and Find Full Text PDFA photonic implementation of a practical broadband RF Hilbert transformer is demonstrated by using a four-tap transversal system. An almost ideal 90 degrees phase shift with less than 3 dB of amplitude ripple has been achieved from 2.4 to 17.
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