Multipath Separation-Direction of Arrival (MS-DOA) with Genetic Search Algorithm for HF channels

Cataloged from PDF version of article.Direction-of-Arrival (DOA) defines the estimation of arrival angles of an electromagnetic wave impinging on a set of sensors. For dispersive and time-varying HF channels, where the propagating wave also suffers from the multipath phenomena, estimation of DOA is a very challenging problem. Multipath Separation-Direction of Arrival (MS-DOA), that is developed to estimate both the arrival angles in elevation and azimuth and the incoming signals at the output of the reference antenna with very high accuracy, proves itself as a strong alternative in DOA estimation for HF channels. In MS-DOA, a linear system of equations is formed using the coefficients of the basis vector for the array output vector, the incoming signal vector and the array manifold. The angles of arrival in elevation and azimuth are obtained as the maximizers of the sum of the magnitude squares of the projection of the signal coefficients on the column space of the array manifold. In this study, alternative Genetic Search Algorithms (GA) for the maximizers of the projection sum are investigated using simulated and experimental ionospheric channel data. It is observed that GA combined with MS-DOA is a powerful alternative in online DOA estimation and can be further developed according to the channel characteristics of a specific HF link. (C) 2009 COSPAR. Published by Elsevier Ltd. All rights reserve

Demographic and microbial characteristics of extrapulmonary tuberculosis cases diagnosed in Malatya, Turkey, 2001-2007

<p>Abstract</p> <p>Background</p> <p>Extrapulmonary tuberculosis (EPTB) has an increasing rate in Turkey. The reason remains largely unknown. A better understanding of the demographic and microbial characteristics of EPTB in the Turkish population would extend the knowledgebase of EPTB and allow us to develop better strategies to control tuberculosis (TB).</p> <p><b>Methods</b></p> <p>We retrospectively evaluated clinical and laboratory data of 397 bacteriologically-confirmed TB cases diagnosed during an eight year-period using by chi-square analysis and multivariate logistic regression model.</p> <p>Results</p> <p>Of the 397 study patients, 103 (25.9%) had EPTB and 294 (74.1%) had pulmonary tuberculosis (PTB). The most commonly seen two types of EPTB were genitourinary TB (27.2%) and meningeal TB (19.4%). TB in bone/joints, pleural cavity, lymph nodes, skin, and peritoneal cavity occurred at a frequency ranging from 9.7% to 10.7%. The age distribution was significantly different (P < 0.01) between PTB and EPTB, with patients older than 45 years tending to have an increased risk of EPTB. Furthermore, the distribution of different types of EPTB differed significantly among age groups (P = 0.03). Meningeal and bone and/or joint TB were more commonly observed among the male patients, while lymphatic, genitourinary, and peritoneal TB cases were more frequently seen among females. Unique strain infection was statistically significantly associated with EPTB (OR: 2.82, 95% CI [1.59, 5.00])</p> <p>Conclusions</p> <p>EPTB accounted for a significant proportion of TB cases in Malatya, Turkey between 2001 and 2007. The current study has provided an insight into the dynamics of EPTB in Malatya, Turkey. However, the risk factors for having EPTB in Malatya, Turkey remain to be assessed in future studies using population-based or randomly selected sample.</p

Discordant identification of pediatric severe sepsis by research and clinical definitions in the SPROUT international point prevalence study

Introduction: Consensus criteria for pediatric severe sepsis have standardized enrollment for research studies. However, the extent to which critically ill children identified by consensus criteria reflect physician diagnosis of severe sepsis, which underlies external validity for pediatric sepsis research, is not known. We sought to determine the agreement between physician diagnosis and consensus criteria to identify pediatric patients with severe sepsis across a network of international pediatric intensive care units (PICUs). Methods: We conducted a point prevalence study involving 128 PICUs in 26 countries across 6 continents. Over the course of 5 study days, 6925 PICU patients &lt;18 years of age were screened, and 706 with severe sepsis defined either by physician diagnosis or on the basis of 2005 International Pediatric Sepsis Consensus Conference consensus criteria were enrolled. The primary endpoint was agreement of pediatric severe sepsis between physician diagnosis and consensus criteria as measured using Cohen's ?. Secondary endpoints included characteristics and clinical outcomes for patients identified using physician diagnosis versus consensus criteria. Results: Of the 706 patients, 301 (42.6 %) met both definitions. The inter-rater agreement (? ± SE) between physician diagnosis and consensus criteria was 0.57 ± 0.02. Of the 438 patients with a physician's diagnosis of severe sepsis, only 69 % (301 of 438) would have been eligible to participate in a clinical trial of pediatric severe sepsis that enrolled patients based on consensus criteria. Patients with physician-diagnosed severe sepsis who did not meet consensus criteria were younger and had lower severity of illness and lower PICU mortality than those meeting consensus criteria or both definitions. After controlling for age, severity of illness, number of comorbid conditions, and treatment in developed versus resource-limited regions, patients identified with severe sepsis by physician diagnosis alone or by consensus criteria alone did not have PICU mortality significantly different from that of patients identified by both physician diagnosis and consensus criteria. Conclusions: Physician diagnosis of pediatric severe sepsis achieved only moderate agreement with consensus criteria, with physicians diagnosing severe sepsis more broadly. Consequently, the results of a research study based on consensus criteria may have limited generalizability to nearly one-third of PICU patients diagnosed with severe sepsis

Effects of childhood bronchiectasis on cardiac functions

Background : Bronchiectasis is still a widespread disease in developing countries. It is an important cause of mortality and morbidity. The information on cardiac involvement in bronchiectasis is limited. However, cor pulmonale is common in patients with chronic lung disease, such as cystic fibrosis

The Effect of Tmd on the Periods and Mode Shapes of the Reinforced Concrete Building by Finite Element Analysis

Earthquake engineers have taken many precautions in their building designs to protect and minimize destructive effects. In this way, many new design and reinforcement methods have been developed against seismic loads. The use of a tuned mass damper (TMD) is one of the developed methods. One of the most important negative aspects of the use of TMD is the increase in the structural period. Therefore, in this study, the effects of TMD on periods and mode shapes in simeterically reinforced concrete building model were investigated. For this, two models with and without TMD were created by the finite element method and modal parameters were compared. As a result of the data obtained, it has been observed that the building model makes more balanced displacements, as can be understood from the mode shapes, without increasing the period of the building to a dangerous level. It is known that TMD reduces the seismic effect by acting in the opposite direction to the seismic effect on the structure. Tuned mass damper can be used in structures, provided that it does not increase the structure period too much

The effect of oxytocin treatment on the adult liver of streptozotocin (STZ) - Induced diabetic rats

Diabetes is a factor that causes hepatic damage. This experimental study has been designed to investigate possible therapeutical and protective effects of oxytocin in streptozotocin-(STZ) induced diabetes. Wistar albino rats used in this study were randomly divided into four groups: I) Control Group, II) STZ induced Diabetic Group (STZ Group), III) Diabetic Group with Pre-Oxytocin treatment (Pre-Oxytocin Group) and IV) Diabetic Group with Post-Oxytocin treatment (Post-Oxytocin Group). Rats with blood glucose levels of 200 mg/dL or higher were considered to be diabetic and included in the study. At the end of the 4th week, hepatic tissue samples were taken to be processed for light microscopy. Blood samples were determined for Malondialdehyde (MDA), glutathione (GSH) and Advanced Oxidation Protein Products (AOPP) measurements. The histopathological damage score of hepatic tissue, which was significantly increased in the STZ group, was decreased by oxytocin treatment. According to biochemical data, MDA and AOPP levels were reduced, whereas GSH level was increased in oxytocin-treated groups when compared to STZ group. The present study demonstrates that oxytociri pretreatment reduced the degree of hepatic injury by providing a cellular protection against oxidative stress produced by STZ-induced diabetes mellitus