Performance Analysis of the Differential Evolution and Particle Swarm Optimization Algorithms in Cooperative Wireless Communications

In this study, we evaluate the performance of differential evolution (DE) and particle swarm optimization (PSO) algorithms in free-space optical (FSO) and mobile radio communications systems. In particular, we obtain the optimal transmission distances for multiple-relay nodes in FSO communication systems and optimal relay locations in mobile radio communications systems for the cooperative-diversity networks, using both algorithms. We investigate the performance comparison of DE and PSO algorithms for the parallel decode-and-forward (DF) relaying. Then, we analyze the cost functions. Furthermore, we present the execution time and the stability of the DE and PSO algorithms

Investigation of formation variation of portal vein with multidetector computed tomography

Background: To determine the types, frequency and clinical implications of formation of variations of portal vein with routine abdominal multi detector CT.Methods: MDCT images of 265 patients without any pathology were evaluated. Types and frequencies of formation variations of portal vein were determined.Results: Portail vein formation variations were observed in 186 (70.15%) of our study population. Normal portal vein was detected in 79 (29.8%) images. These variations were classified according to frequency. Normal anatomic structure was determined as type 1. Type 1 was observed in 79 (29.8%) images. As type 2 variation, left gastric vein flows into splenic vein instead of portal vein (60.75%). The type 3 of portal vein variation as uniting of superior mesenteric vein, inferior mesenteric vein and splenic vein at the same trunk to form portal vein was determined 9.43%.Conclusions: This study, which was performed to determine the anatomical variations of portail vein, makes the type 2 variation rate higher than the other studies. This information is different from the classical anatomy information. In addition, we are able to make the radiologists and surgeons highly capable of both recognition and functionality of the results

P Wave Duration And Dispersion In Patients With Hyperthyroidism And The Short-term Effects Of Antithyroid Treatment

Background: Prolonged P wave duration and P wave dispersion (PWD) have been associated with an increased risk for atrial fibrillation (AF). Hyperthytodism is a frequent cause of atrial fibrillation (AF). Methods: Forty-two patients with newly diagnosed overt hyperthyroidism and 20 healthy people were enrolled in the study. Transthoracic echocardiography, 12 lead surface ECG and thyroid hormone levels were studied at the time of enrollment and after achievement of euthyroid state with propylthiouracil treatment. Results: Maximum P wave duration (Pmax) (97.4±14.6 vs. 84.2±9.5 msec, p<0.001), PWD (42.9±10.7 vs. 31.0±6.2 msec, p<0.001), deceleration (DT) (190.7±22.6 vs. 177.0±10.2 msec, p=0.013) and isovolumetric relaxation times (IVRT) (90.9±11.2 vs. 79.6±10.5 msec, p<0.001) were significantly higher in hyperthyroid patients compared to control group. Pmax and PWD were significantly correlated with the presence of hyperthyroidism. Pmax (97.4±14.6 to 84.3±8.6 msec, p<0,001) Pmin (54.1±8.6 to 48.1±8.5 msec, p=0.002), PWD (42.9±10.7 to 35.9±8.1 msec, p=0.002) and DT (190.7±22.6 to 185.5±18.3, p=0.036) were significantly decreased after achievement of euthyroid state in patients with hyperthyroidism. Diastolic dyfunction was seen in 5 patients at hyperthroid state but only in one patient at euthyroid state. Conclusions: Hyperthyroidism is associated with prolonged P wave duration and dispersion. Achievement of euthyroid state with propylthiouracil treatment results in shortening of P wave variables. Diastolic function may have a partial effect for the increased Pmax and PWD. Shortening of Pmax and PWD may be a marker for the prevention of AF with the anti-thyroid treatment

The effects of iron deficiency anemia on p wave duration and dispersion

OBJECTIVES: The association between P wave dispersion and iron deficiency anemia has not been documented in the literature. In this study, we evaluated P wave dispersion in patients with iron deficiency anemia and the possible relationships between P wave dispersion and other echocardiographic parameters. INTRODUCTION: The iron status of an individual may play an important role in cardiovascular health. Anemia is an independent risk factor for adverse cardiovascular outcomes. P wave dispersion is a simple electrocardiographic marker that has a predictive value for the development of atrial fibrillation. Apart from cardiovascular diseases, several conditions, such as seasonal variation, alcohol intake and caffeine ingestion, have been demonstrated to affect P wave dispersion. METHODS: The study included 97 patients who had iron deficiency anemia and 50 healthy subjects. The cases were evaluated with a clinical examination and diagnostic tests that included 12-lead electrocardiography and transthoracic echocardiography. RESULTS: Compared to the control group, patients with iron deficiency anemia showed significantly longer maximum P wave duration (Pmax) (91.1±18.0 vs. 85.8±6.7 msec, p=0.054), P wave dispersion (PWD) (48.1±7.7 vs. 40.9±5.6 msec,

The role of dislocation-induced scattering in electronic transport in GaxIn1-xN alloys

Abstract Electronic transport in unintentionally doped GaxIn1-xN alloys with various Ga concentrations (x = 0.06, 0.32 and 0.52) is studied. Hall effect measurements are performed at temperatures between 77 and 300 K. Temperature dependence of carrier mobility is analysed by an analytical formula based on two-dimensional degenerate statistics by taking into account all major scattering mechanisms for a two-dimensional electron gas confined in a triangular quantum well between GaxIn1-xN epilayer and GaN buffer. Experimental results show that as the Ga concentration increases, mobility not only decreases drastically but also becomes less temperature dependent. Carrier density is almost temperature independent and tends to increase with increasing Ga concentration. The weak temperature dependence of the mobility may be attributed to screening of polar optical phonon scattering at high temperatures by the high free carrier concentration, which is at the order of 1014 cm−2. In our analytical model, the dislocation density is used as an adjustable parameter for the best fit to the experimental results. Our results reveal that in the samples with lower Ga compositions and carrier concentrations, alloy and interface roughness scattering are the dominant scattering mechanisms at low temperatures, while at high temperatures, optical phonon scattering is the dominant mechanism. In the samples with higher Ga compositions and carrier concentrations, however, dislocation scattering becomes more significant and suppresses the effect of longitudinal optical phonon scattering at high temperatures, leading to an almost temperature-independent behaviour.</jats:p

Trace Elements, Heavy Metals and Vitamin Levels in Patients with Coronary Artery Disease

Aim: In the present study, we aimed to assess serum concentrations of zinc (Zn), copper (Cu), iron (Fe), cadmium (Cd), lead (Pb), manganese (Mn), vitamins A (retinol), D (cholecalciferol) and E (α-tocopherol) in patients with coronary artery disease (CAD) and to compare with healthy controls