35 research outputs found
Sensitive and Accurate Dispersion Map Extraction of HNLFs by Frequency Tuning of a Degenerate FWM
A sensitive and accurate method for dispersion map extraction along an arbitrarily profiled highly nonlinear fiber (HNLF) is proposed. High sensitivity is achieved by positioning the wavelength of a signal at the band edge of the modulation instability (MI) spectrum generated by an intense degenerate four wave mixing (FWM) pump. In doing so, the to-be-extracted dispersion fluctuations leave a more drastic effect on the FWM-generated power since they either inflate or deflate theMI spectrum. The accuracy of the method is increased by monitoring the distribution of power along the fiber. Once the power distribution is measured along the fiber, dispersion map of the HNLF is extracted using an appropriate inverse algorithm, which reconstructs the dispersion with a highlevel ofaccuracy.
Mapping Dispersion Fluctuations along Optical Fibers Using Brillouin Probing and a Fast Analytic Calculation
A simple analytic formula is derived to extract tiny dispersion fluctuations along highly nonlinear fibers from distributed measurements of parametric gain. A refined BOTDA scheme, suitable to track Kerr processes, enables low noise measurements
Distributed Measurement of Signal Power Evolution in a Phase Sensitive Parametric Amplifier
A method to measure the signal power evolution along phase-sensitive parametric amplifiers is proposed using Brillouin optical time-domain analysis. Different evolutions along the fiber are reported by varying input wave phases, including amplification and de-amplification
Power evolution along phase-sensitive parametric amplifiers: an experimental survey
We propose and experimentally demonstrate a method based on Brillouin optical time-domain analysis to measure the longitudinal signal power distribution along phase-sensitive fiber-optical parametric amplifiers (PS-FOPAs). Experimental results show that the amplification of a PS-FOPA could go through different longitudinal profiles and yet finish with the same overall gain. This behavior is in sheer contrast with theoretical expectations, according to which longitudinal gain distribution should follow certain profiles determined by the initial relative phase difference but can never end up in the same overall gain. The gap between theory and experiment only becomes evident when the pump wavelength is within the fluctuation range of the zero dispersion wavelength (ZDW) of the PS-FOPA
The effectiveness of CPR training during anesthesia internship rotation on improvement of interns, knowledge and clinical skills of Lorestan university of medical sciences
Background : Since only the correct and effective Cardiopulmonary Resuscitation (CPR) can increase the survival of patients with cardiopulmonary arrest, the aim of this study is to determine the effects of CPR training in the anesthetioligy ward to improve CPR knowledge and clinical skills of interns of Lorestan university of medical sciences. Materials and Methods : A 10-month Educational experimental study was done on 31 undergraduate medical students at Lorestan university of medical sciences in 2013. During a period of 15 days of anesthesiology internship course, all these students underwent CPR training including Basic Life Support ( BLS ), Advanced Cardiac Life Support ( ACLS ) and practical skills. Data were collected via a questionnaire with 4 parts including demographic, pre and post knowledge and skills as standpoint of interns and ward,s professor. Results: After training the mean of score about knowledge of CPR and its practical skills significantly increased from 5.68 to 7.94 and 10.65 to 23.45 respectivly (PV=0.0001) . A significant relationship between preinternship exam score and knowledge of CPR before anesthesiology internship course was shown (PV=0.001), but there was no significant relationship with practical skills score pre and post CPR training in anesthesilogy ward.(PV=0.38) Conclusion: The CPR training course in anesthetiology ward leads to significant increase in CPR skills and Knowledge of medical interns. Adding this course to undergraduated medical students is essentia
Cross-situational learning of low frequency words: The role of context familiarity and age of exposure
Higher frequency has been shown to have a positive effect on the acquisition of words and other linguistic items in children. An important question that needs to be answered then is how children learn low frequency items. In this study, we investigate the acquisition of meanings for low frequency words through computational modeling. We suggest that for such words, the familiarity of the context they appear in has an important effect on their acquisition. We note that context familiarity is confounded with another factor, namely the age of exposure to a word, and hence examine the independent role of each of the two factors on word learning. Cross-situational Word Learning Learning the meaning of words is a challenging task for young children, especially given that most words are learne
JAK inhibitors in lichen planus: a review of pathogenesis and treatments
Lichen planus (LP) is an auto-inflammatory skin disorder identified by a presence of T-cell lymphocytes at the dermal-epidermal junction. It is hypothesized that the INF–γ/CXCL10 axis fulfills a major role in the onset and persistence of chronic inflammation in LP. Since Janus kinases (JAKs) are involved in the transduction of INF–γ signals, they may be good targets for LP treatment. Several case reports and case series described the safety and efficacy of upadacitinib (2 articles), tofacitinib (6 articles), baricitinib (4 articles), and Ruxolitinib (1 Article) in the treatment of LP variants. The predominant variants that JAK inhibitors improved were lichen planopilaris, nail LP, and erosive LP. Considering the role of the JAK pathway in LP pathogenesis and the evidence provided by these reports, it seems JAK inhibitors would be effective therapeutic agents for LP treatment. Hence, these agents should be trialed and evaluated further