1,887 research outputs found

    Fast System Identification and Model Reduction Solvers

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    Stability and evolution of electromagnetic solitons in relativistic degenerate laser plasmas

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    The dynamical behaviors of electromagnetic (EM) solitons formed due to nonlinear interaction of linearly polarized intense laser light and relativistic degenerate plasmas are studied. In the slow motion approximation of relativistic dynamics, the evolution of weakly nonlinear EM envelope is described by the generalized nonlinear Schr{\"o}dinger (GNLS) equation with local and nonlocal nonlinearities. Using the Vakhitov-Kolokolov criteria, the stability of an EM soliton solution of the GNLS equation is studied. Different stable and unstable regions are demonstrated with the effects of soliton velocity, soliton eigenfrequency, as well as the degeneracy parameter R=pFe/mecR=p_{Fe}/m_ec, where pFep_{Fe} is the Fermi momentum and mem_e the electron mass, and cc is the speed of light in vacuum. It is found that the stability region shifts to an unstable one and is significantly reduced as one enters from the regimes of weakly relativistic (R≪1)(R\ll1) to ultrarelativistic (R≫1)(R\gg1) degeneracy of electrons. The analytically predicted results are in good agreement with the simulation results of the GNLS equation. It is shown that the standing EM soliton solutions are stable. However, the moving solitons can be stable or unstable depending on the values of soliton velocity, the eigenfrequency or the degeneracy parameter. The latter with strong degeneracy (R>1)(R>1) can eventually lead to soliton collapse.Comment: 9 pages, 5 figure

    Ultra-wide detuning planar Bragg grating fabrication technique based on direct UV grating writing with electro-optic phase modulation

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    A direct UV grating writing technique based on phase-controlled interferometry is proposed and demonstrated in a silica-on-silicon platform, with a wider wavelength detuning range than any previously reported UV writing technology. Electro-optic phase modulation of one beam in the interferometer is used to manipulate the fringe pattern and thus control the parameters of the Bragg gratings and waveguides. Various grating structures with refractive index apodization, phase shifts and index contrasts of up to 0.8Ă—10-3 have been demonstrated. The method offers significant time/energy efficiency as well as simplified optical layout and fabrication process. We have shown Bragg gratings can be made from 1200 nm to 1900 nm exclusively under software control and the maximum peak grating reflectivity only decreases by 3dB over a 250 nm (~32THz) bandwidth

    Gold Market Analyzer using Selection based Algorithm

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    Gold is the most important and valuable element right from its discovery. It is the most significant element at present and also the most valuable asset to. In the present market scenario the investors use gold as the security for their shares investment. During International trade all the countries use gold as their main mode of transaction. It is seen that all the currencies accepted by the International market are having the gold as the backup for their economy. The prices of gold are rising day by day continuously. As we see in the history of gold market the present prices of gold are much high as compare to the past values and that's why the gold market has attracted the most attention. The paper focus on the continuous changing in the gold rates, investment policies depend on the forecasting of trends in gold which will help the data mining companies to minimize the risk The description of the future situation on the basis of present trends is just not limited to the forecasting the prices. The knowledge discovers by the data mining techniques is gathered from the different gold related websites and also from the jewellers database. It is much more important for the ornaments making companies to know the demand and the requirements for the ornaments during the unstable (uncertain) market conditions. For the classification purpose the maid and sale database was gathered from the nearest jewellery shops of the past 5 years. The prediction is done after complete analysis of the gathered data set. With this the paper concentrate on making the information available about the government and private schemes related to gold market on one place. The paper proposes the system that gives the total access to the registered user and limited access to the unregistered user to get the required information of gold. The latest updates are provided to the registered user by sending mail or text message when the user was offline

    Comorbid Medical Conditions as Predictors of Overall Survival in Glioblastoma Patients

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    Glioblastoma (GBM) is an aggressive central nervous system tumor with a poor prognosis. This study was conducted to determine any comorbid medical conditions that are associated with survival in GBM. Data were collected from medical records of all patients who presented to VCU Medical Center with GBM between January 2005 and February 2015. Patients who underwent surgery/biopsy were considered for inclusion. Cox proportional hazards regression modeling was performed to assess the relationship between survival and sex, race, and comorbid medical conditions. 163 patients met inclusion criteria. Comorbidities associated with survival on individual-characteristic analysis included: history of asthma (Hazard Ratio [HR]: 2.63; 95% Confidence Interval [CI]: 1.24–5.58; p = 0.01), hypercholesterolemia (HR: 1.95; 95% CI: 1.09–3.50; p = 0.02), and incontinence (HR: 2.29; 95% CI: 0.95–5.57; p = 0.07). History of asthma (HR: 2.22; 95% CI: 1.02–4.83; p = 0.04) and hypercholesterolemia (HR: 1.99; 95% CI: 1.11–3.56; p = 0.02) were associated with shorter survival on multivariable analysis. Surgical patients with GBM who had a prior history of asthma or hypercholesterolemia had significantly higher relative risk for mortality on individual-characteristic and multivariable analyses

    Liver and Intestine Transplantation in the United States, 1996–2005

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72937/1/j.1600-6143.2007.01782.x.pd

    Psychometric evaluation of the Connor-Davidson Resilience Scale among Iranian population

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    Background The resilience construct is considered a personal trait composed of multiple aspects. Connor–Davidson Resilience Scale is a standard tool composed of fve factors and 25 items. This study aimed to determine the psychometric properties of this scale. Methods In this cross-sectional study, after the scale translation, the factorial structural validity was assessed via the confrmatory factor analysis with 70 180 samples. Internal consistency, composite reliability, convergent validity were assessed by calculating Cronbach’s alpha, composite reliability, maximum reliability, and Average Variance Extracted. The discriminant validity was assessed using Heterotrait-monotrait ratio of correlations matrix and also, measure invariance was evaluated. Results The original fve-factor model had good model ft indices but due to low factor loading of item 2 and 20, the model was modifed. The Cronbach’s alpha and composite reliability for four factors were above 0.7 (except for factor 5). The convergent validity for all fve factors were achieved. Between factors 1 with 2 and 4, 2 with 3 and 4 discriminant validity was not established (correlations>0.9) and the results suggested that there might be a secondorder latent construct behind these factors. Therefore, a second-order assessment was performed. The results of the second-order latent construct assessment showed a good goodness-of ft and strong measurement invariance for both men and women. Conclusion The 23-item version of Connor-Davidson Resilience Scale is a reliable and valid scale to measure resilience as a complex construct in the Iran contextinfo:eu-repo/semantics/publishedVersio
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