First hours of the GRB 030329 optical afterglow

We present the first results of the observations of the extremely bright optical afterglow of gamma-ray burst (GRB) 030329 with the 1.5m Russian-Turkish telescope RTT150 (TUBITAK National Observatory, Bakyrlytepe, Turkey). RTT150 was one of the first 1.5m-class telescopes pointed to the afterglow. Observations were started approximately 6 hours after the burst. During the first 5 hours of our observations the afterglow faded exactly as a power law with index -1.19+-0.01 in each of the BVRI Bessel filters. After that, in all BVRI filters simultaneously we observe a steepening of the power law light curve. The power law decay index smoothly approaches the value ~= -1.9, observed by other observatories later. This power law break occurs at t-t_0 =0.57 days and lasts for +-0.1 days. We observe no variability above the gradual fading with the upper limits 10--1% on time scales 0.1--1000s. Spectral flux distribution in four BVRI filters corresponds to the power law spectrum with spectral index \alpha=0.66+-0.01. The change of the power law decay index in the end of our observations can be interpreted as a signature of collimated ultrarelativistic jet. The afterglow flux distribution in radio, optical and x-rays is consistent with synchrotron spectrum. We continue our observations of this unique object with RTT150.Comment: Astronomy Letters, Vol. 29, No. 9, p. 573; 6 pages, 5 figures; pagination corrected; the original Russian version can be found at http://hea.iki.rssi.ru/~br/030329/pfh030329.pd

Development of a Fiber Laser with Independently Adjustable Properties for Optical Resolution Photoacoustic Microscopy

Photoacoustic imaging is based on the detection of generated acoustic waves through thermal expansion of tissue illuminated by short laser pulses. Fiber lasers as an excitation source for photoacoustic imaging have recently been preferred for their high repetition frequencies. Here, we report a unique fiber laser developed specifically for multiwavelength photoacoustic microscopy system. The laser is custom-made for maximum flexibility in adjustment of its parameters; pulse duration (5–10 ns), pulse energy (up to 10 μJ) and repetition frequency (up to 1 MHz) independently from each other and covers a broad spectral region from 450 to 1100 nm and also can emit wavelengths of 532, 355, and 266 nm. The laser system consists of a master oscillator power amplifier, seeding two stages; supercontinuum and harmonic generation units. The laser is outstanding since the oscillator, amplifier and supercontinuum generation parts are all-fiber integrated with custom-developed electronics and software. To demonstrate the feasibility of the system, the images of several elements of standardized resolution test chart are acquired at multiple wavelengths. The lateral resolution of optical resolution photoacoustic microscopy system is determined as 2.68 μm. The developed system may pave the way for spectroscopic photoacoustic microscopy applications via widely tunable fiber laser technologies

Noise Reduction in Photoacoustic Imaging using Wavelet Transform

Fotoakustik mikroskop (Photoacoustic Microscopy, PAM) fotoakustik etki temeline dayanan ve son yıllarda geliştirilmeye başlayan hibrid bir görüntüleme tekniğidir. Optik kontrastı akustik olarak algılayan sistem yapısı sayesinde optik difüzyon sınırının ötesinde derin bir görüntülemeyi yüksek çözünürlükle sunabilmektedir. PAM sistemi ile görüntülemede kaydedilen sinyaller, sistem bileşenleri ve çevresel etkilerle gürültüye maruz kalmaktadır. Yapılan çalışmanın ilk aşamasında akustik dalga denkleminin çözümüyle oluşturulan akustik sinyal üzerine belirli oranlarda sentetik gürültüler eklenmiştir. Gürültülü sinyallere farklı ana dalgacıklar kullanılarak ayrık dalgacık dönüşümü ile filtreleme işlemi uygulanmış ve filtreleme performansının değerlendirilmesi için sinyaller üzerinde gürültü metrikleri hesaplanmıştır. İkinci aşamada, ilk aşamada elde edilen veriler doğrultusunda PA sinyallerin filtrelenmesi için uygun ana dalgacıklar seçilmiş filtrelenen sinyaller ile görüntüler oluşturularak, görüntüler üzerinde gürültü metrikleri incelenmiştir // Photoacoustic microscopy (PAM) is a hybrid imaging technique based on the photoacoustic effect and which has begun to develop in recent years. Thanks to the system structure that senses the optical contrast acoustically, it is able to present deep imaging with high resolution beyond the optical diffusion limit. Signals recorded in imaging with the PAM system are exposed to noise by system components and environmental effectcs. In the first stage of the work, a synthetic noise is added at a certain rate on the acoustic signal generated by the solution of the acoustic wave equation. Noisy signals are filtered using discrete wavelet transforms using different main wavelets and noise metrics are calculated on the signals to evaluate the filtering performance. In the second step, the noise metrics are examined on the images by generating the images with the filtered wavelet signals, which are suitable for filtering the PA signals in the direction of the data obtained in the first stage

Optical resolution photoacoustic imaging of multiple probes via single fiber laser with independently adjustable parameters

[No abstract available

Development of a Fiber Laser with Independently Adjustable Properties for Optical Resolution Photoacoustic Microscopy

Photoacoustic imaging is based on the detection of generated acoustic waves through thermal expansion of tissue illuminated by short laser pulses. Fiber lasers as an excitation source for photoacoustic imaging have recently been preferred for their high repetition frequencies. Here, we report a unique fiber laser developed specifically for multiwavelength photoacoustic microscopy system. The laser is custom-made for maximum flexibility in adjustment of its parameters; pulse duration (5-10 ns), pulse energy (up to 10 μJ) and repetition frequency (up to 1 MHz) independently from each other and covers a broad spectral region from 450 to 1100 nm and also can emit wavelengths of 532, 355, and 266 nm. The laser system consists of a master oscillator power amplifier, seeding two stages; supercontinuum and harmonic generation units. The laser is outstanding since the oscillator, amplifier and supercontinuum generation parts are all-fiber integrated with custom-developed electronics and software. To demonstrate the feasibility of the system, the images of several elements of standardized resolution test chart are acquired at multiple wavelengths. The lateral resolution of optical resolution photoacoustic microscopy system is determined as 2.68 μm. The developed system may pave the way for spectroscopic photoacoustic microscopy applications via widely tunable fiber laser technologies. © The Author(s) 2016

Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals

Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice

RoboCup 2011: Robot Soccer World Cup XV

XXV, 600 p.online resource