This study studies the performance of multihop free-space optical systems using the subcarrier binary phase-shift keying modulation over atmospheric turbulence channels. The authors propose a modified relaying strategy, termed ‘amplify– decode-and-forward’, realised by using avalanche photodiode (APD) receivers. The outage probability of the proposed system is analytically derived considering t...

This paper studies the performance of multihop free-space optical (FSO) systems using the subcarrier binary phase-shift keying modulation (BPSK) over atmospheric turbulence channels. We propose a modified relaying strategy, termed amplify-decode-and-forward (ADF), realised by using avalanche photodiode (APD) receivers. The outage probability of the proposed system is analytically derived consid...

Q. Yue, C. B. Zhang: School of Metallurgy Engineering, Anhui University of Technology, Ma’ anshan, China. X. Z. WANG: School of Mechanic Engineering, Anhui University of Technology, Ma’ anshan, China Fluid flows in a two-strand tundish for slab continuous casting were performed with mathematical simulation methods. The molten steel flow velocity fields in the tundish with a turbulence inhibitor...

Both heart rate variability (HRV) and heart rate turbulence (HRT) are established tools to study cardiac autonomic activity. Short-term studies of HRV had been reported to be stable for autonomic function assessment. However, there is little information on whether short-term HRT assessment is comparable to 24 h assessment. The aim of the study is to identify the relationship of HRT values betwe...

INTRODUCTION Cardiac autonomic neuropathy (CAN) causes substantial morbidity and increased mortality in patients with diabetes mellitus (DM). Besides heart rate variability (HRV), heart rate turbulence (HRT) is an important method of assessment of cardiac autonomic regulation. The aim of the study was to assess the correlation between HRT and diabetic control. MATERIAL AND METHODS Fifty-nine ...

OBJECTIVE Fibromyalgia is characterized by diffuse musculoskeletal pain and discomfort. There are several reports regarding autonomic nervous system dysfunction in patients with fibromyalgia. Heart rate turbulence is expressed as ventriculophasic sinus arrhythmia and has been considered to reflect cardiac autonomic activity. Heart rate turbulence has been shown to be an independent and powerful...

We discuss the relative grain motions due to MHD turbulence in interstel-lar medium. It has been known for decades that turbulent drag is an efficient way to induce grain relative motions. However, earlier treatments disregarded magnetic field and used Kolmogorov turbulence. Unlike hydro turbulence, MHD turbulence is anisotropic on small scales. Moreover, compressible modes are important for MH...

Klíčová slova kardiální autonomní funkce – turbulence srdeční frekvence – migréna Abstract Studies of autonomic nervous system function in patients with migraine have shown conflicting results. Heart rate turbulence (HRT) is a new method to assess cardiac autonomic function. HRT impairment reflects cardiac autonomic dysfunction. The aim of the present study was to determine validation of HRT as...

Predator–prey encounter and capture rates are key drivers of population dynamics of planktonic organisms. Turbulent mixing gives rise to enhanced encounter rates, but high turbulence levels may reduce capture rates. We present an estimate for the optimum turbulence level for a predator that is characterized by a number of parameters, such as its range of interception. A limit at small spatial s...