Frequency-Doubling of Femtosecond Pulses in “Thick” Nonlinear Crystals With Different Temporal and Spatial Walk-Off Parameters

We present a comparative study on frequency-doubling characteristics of femtosecond laser pulses in thick nonlinear crystals with different temporal and spatial walk-off parameters. Using single-pass second harmonic generation (SHG) of 260 fs pulses at 1064 nm from a high-average-power femtosecond Yb-fiber laser in 5-mm-long crystals of β-BaB2O4 (BBO) and BiB3O6 (BIBO), we find that for comparable values of temporal and spatial walk-off parameters in each crystal, the optimum focusing condition for SHG is more strongly influenced by spatial walk-off than temporal walk-off. It is also observed that under such conditions, the Boyd and Kleinman theory commonly used to define the optimum focusing condition for frequency-doubling of cw and long-pulse lasers is also valid for SHG of ultrafast lasers. We also investigate the effect of focusing on the spectral, temporal, and spatial characteristics of the second harmonic (SH) radiation, as well as angular acceptance bandwidth for the SHG process, under different temporal and spatial walk-off conditions in the two crystalsPeer ReviewedPostprint (author's final draft

MENGGUNAKAN METODE DISKUSI UNTUK MENINGKATKAN KEMAMPUAN MENULIS PADA SISWA KELAS IV SD NEGERI NEUHEUN KABUPATEN ACEH BESAR

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Is lumbar facet joint tropism developmental or secondary to degeneration? An international, large-scale multicenter study by the AOSpine Asia Pacific Research Collaboration Consortium

published_or_final_versio

Critical values of facet joint angulation and tropism in the development of lumbar degenerative spondylolisthesis: an international, large-scale multicenter study by the AOSpine Asia Pacific Research Collaboration Consortium

published_or_final_versio

Complex Discrete Wavelet Transform-Based Image Denoising

Dual tree complex discrete wavelet transform is implemented for denoising as an important image processing application. Two wavelet trees are used, one generating the real part of the wavelet coefficients tree and the other generating the imaginary part tree. A general computer program computing two dimensional dual tree complex wavelet transform is written using MatLab V.7.0. for a general (NxN) two dimensional signal. This paper introduces firstly a proposed method of computing one and twodimensional dual tree complex wavelet transform .The proposed method reduces heavily processing time for decomposition of image keeping or overcoming the quality of reconstructed images. Also, the inverse procedures of all the above transform for multi- dimensional cases verified. Secondly, many techniques are implemented for denoising of gray scale image. A new threshold method is proposed and compared with the other thresholding methods. For hard thresholding, PSNR gives (13.548) value while the PSNR was increased in the proposed soft thresholding, it gives (14.1734) PSNR value when the noise variance is (20). Denoising schemes are tested on Peppers noise image to find its effect on denoising application. The noisy version has SNR equals to (11.9373 dB), the denoising image using WT has SNR equals to (17.4661 dB), the denoising image using SWT has SNR equals to (18.1459 dB), the denoising image using WPT has SNR equals to (19.3640 dB), the denoising image using Complex Discrete Wavelet Transform has SNR equals to (21.9138 dB) using hard threshold and has SNR equals to (22.1393 dB) using soft threshold. Matlab V.7.0 is used for simulation

One-year clinical outcome of patients with nonvalvular atrial fibrillation: Insights from KERALA-AF registry.

BackgroundWe report patient characteristics, treatment pattern and one-year clinical outcome of nonvalvular atrial fibrillation (NVAF) from Kerala, India. This cohort forms part of Kerala Atrial Fibrillation (KERALA-AF) registry which is an ongoing large prospective study.MethodsKERALA-AF registry collected data of adults with previously or newly diagnosed atrial fibrillation (AF) during April 2016 to April 2017. A total of 3421 patients were recruited from 53 hospitals across Kerala state. We analysed one-year follow-up outcome of 2507 patients with NVAF.ResultsMean age at recruitment was 67.2 years (range 18-98) and 54.8% were males. Main co-morbidities were hypertension (61.2%), hyperlipidaemia (46.2%) and diabetes mellitus (37.2%). Major co-existing diseases were chronic kidney disease (42.1%), coronary artery disease (41.6%), and chronic heart failure (26.4%). Mean CHA2DS2-VASc score was 3.18 (SD ± 1.7) and HAS-BLED score, 1.84 (SD ± 1.3). At baseline, use of oral anticoagulants (OAC) was 38.6% and antiplatelets 32.7%. On one-month follow-up use of OAC increased to 65.8% and antiplatelets to 48.3%. One-year all-cause mortality was 16.48 and hospitalization 20.65 per 100 person years. The main causes of death were cardiovascular (75.0%), stroke (13.1%) and others (11.9%). The major causes of hospitalizations were acute coronary syndrome (35.0%), followed by arrhythmia (29.5%) and heart failure (8.4%).ConclusionsDespite high risk profile of patients in this registry, use of OAC was suboptimal, whereas antiplatelets were used in nearly half of patients. A relatively high rate of annual mortality and hospitalization was observed in patients with NVAF in Kerala AF Registry