Numerical solution of linear time delay systems using Chebyshev-tau spectral method

In this paper, a hybrid method based on method of steps and a Chebyshev-tau spectral method for solving linear time delay systems of differential equations is proposed. The method first converts the time delay system to a system of ordinary dierential equations by the method of steps and then employs Chebyshev polynomials to construct an approx- imate solution for the system. In fact, the solution of the system is expanded in terms of orthogonal Chebyshev polynomials which reduces the solution of the system to the solution of a system of algebraic equations. Also, we transform the coefficient matrix of the algebraic system to a block quasi upper triangular matrix and the latter system can be solved more efficiently than the first one. Furthermore, using orthogonal Chebyshev polynomials enables us to apply fast Fourier transform for calculating matrix-vector multiplications which makes the proposed method to be more efficient. Consistency, stability and convergence analysis of the method are provided. Numerous numerical examples are given to demonstrate efficiency and accuracy of the method. Comparisons are made with available literature

Financial burden of burn injuries in iran: A report from the burn registry program Le coût du traitement des brûlures en iran: Un rapport du registre des brûlés

Understanding the cost of burn treatment is very important for patients, their families, governmental authorities and insurance companies. It alleviates patient and familial stress, provides a framework for better use of resources, and facilitates better performance between burn centers. Hospital burn costs can provide a basis for authorities to budget for acute burn treatment, for further management of chronic complications, and for planning prevention and public educational programs in Iran. To identify costs we used data from our burn registry program. Over the two-year assessment period, we treated roughly 28,700 burn patients, 1,721 of whom were admitted, with a mortality rate of 5.9. The male to female ratio was 1.7:1 (63 male; 37 female). Flame burns were most frequent (49.8) followed by scalds (35.7). Mean hospital stay was 14.41 days (range 0-64 days). Mean TBSA was 17.39. Skin grafts were carried out in 65.4 of the patients, with a mean of 5.2 surgeries per patient. The total cost of all patient admissions over the two years was US 4,835,000. The maximum treatment cost for one patient was US 91,000. The mean cost per patient was US 2,810 (29,500,000 Rials). The mean cost for each percent of burn was US 162. The mean cost for a one-day stay in hospital was US 195. The mean cost of each operation was US 540. Patients who contracted infections endured longer hospital stays, meaning increased costs of US 195 per day. With comparable outcome and results, the cost of burn treatment in Iran is cheaper than in the US and Europe. © 2015, Mediterranean Club for Burns and Fire Disasters. All rights reserved

Fast atom diffraction inside a molecular beam epitaxy chamber, a rich combination

Two aspects of the contribution of grazing incidence fast atom diffraction (GIFAD) to molecular beam epitaxy (MBE) are reviewed here: the ability of GIFAD to provide \emph{in-situ} a precise description of the atomic-scale surface topology, and its ability to follow larger-scale changes in surface roughness during layer-by-layer growth. Recent experimental and theoretical results obtained for the He atom beam incident along the highly corrugated $[ 1\bar{1}0 ]$ direction of the $\beta_{2}$(2$\times$4) reconstructed GaAs(001) surface are summarized and complemented by the measurements and calculations for the beam incidence along the weakly corrugated [010] direction where a periodicity twice smaller as expected is observed. The combination of the experiment, quantum scattering matrix calculations, and semiclassical analysis allows in this case to reveal structural characteristics of the surface. For the in situ measurements of GIFAD during molecular beam epitaxy of GaAs on GaAs surface we analyse the change in elastic and inelastic contributions in the scattered beam, and the variation of the diffraction pattern in polar angle scattering. This analysis outlines the robustness, the simplicity and the richness of the GIFAD as a technique to monitor the layer-by-layer epitaxial growth

Analysis of the gamma spectra of the uranium, actinium, and thorium decay series

This report describes the identification of radionuclides in the uranium, actinium, and thorium series by analysis of gamma spectra in the energy range of 40 to 1400 keV. Energies and absolute efficiencies for each gamma line were measured by means of a high-resolution germanium detector and compared with those in the literature. A gamma spectroscopy method, which utilizes an on-line computer for deconvolution of spectra, search and identification of each line, and estimation of activity for each radionuclide, was used to analyze soil and uranium tailings, and ore

A study on the ethical components of nursing practice (moral distress, ethical sensitivity, ethical decision)

This paper is an applied research in terms of objective and a descriptive research in terms of method. Having prepared the research plan, a questionnaire was designed based on goals and hypotheses of the research and was sent to the statistical universe. Also this paper is a field research in terms of data collection. As regards theoretical bases of the research, library data collection method has been applied. So, the required data has been gathered by referring to the related references, books, libraries and so on. To design a questionnaire and gather the opinions of the statistical universe members, field study method and researcher-made questionnaire have been used. The statistical universe comprises nurses and head of ICU and head nurses of Najmieh Hospital in Tehran. The respondents were selected by random sampling method. Also to estimate sample size, Morgan table was applied. The statistical universe consists of 65 members and according to the table, 56 questionnaires were determined for the research. So 60 questionnaires were sent and 58 ones were returned. Face and content validity of the research tool were approved by experts. The test reliability was estimated 0.777 by calculating Cronbach's alpha coefficient. In this paper, factor analysis based on partial least squares structural equations method has been applied to analyze more important factors and coefficients, estimate independent variables coefficients and even determine effectiveness of each independent variable on each other and determine appropriateness of the questions and their coefficients in explaining the related index. The main result of this paper presents a proper model for the relation of effective variables on nurse performance by using regression model. © IDOSI Publications, 2014

Comparisons of competitive enzyme-linked immunosorbent assay and one step RT-PCR tests for the detection of Bluetongue virus in south west of Iran

Bluetongue is a noncontagious, arthropod-borne viral disease of both domestic and wild ruminants. Bluetongue virus (BTV) is the type of species of the genus Orbivirus within the family Reoviridae. BTV is endemic in some areas with cattle and wild ruminants serving as reservoirs for the virus. Clinical symptoms are often seen in sheep. There are several methods for the detection of Bluetongue virus, among them the molecular technique like RT-PCR is considered as the most sensitive and reliable one. The aim of this study was to comprise competitive enzyme-linked immunosorbent assay (C-ELISA) with one step RT-PCR test for the detection of BTV in sheep. A total of 770 blood samples were obtained from sheep (265 serum positive samples and 505 serum negative samples in C-ELISA). According to our data, out of the 265 serum positive samples in ELISA test, 234 were positive in RT-PCR assay whereas all serum negative samples were negative in RT-PCR experiment. According to the results, the PCR assay was more sensitive and reliable than ELISA technique for the diagnosis of Bluetongue virus.Key words: Bluetongue virus, C-ELISA, RT- PCR, Sheep, Iran

Blood pressure alterations in burn patients with septic shock under hydrocortisone treatment

Background and Objectives: Hydrocortisone is widely used in septic shock cases resistant to fluid and vasopressor therapy. It may result in increased blood pressure and survival. However the efficacy is no established among patients with severe burn and septic shock. Accordingly it was assessed in this study. Materials and Methods: The patients older than 14 years of age with resistant septic shock were enrolled during one-year period. The hydrocortisone was prescribed 100 mg three times per day and the alterations in systolic and diastolic blood pressures were recorded. Results: Twenty-nine patients were enrolled including 19 men and 10 women. The mean age was 37 ± 19 years and the mean burn surface area was 60 ± 20. Fourteen patients had positive blood culture. The most common isolated microorganism were Pseudomonas aeuroginosa in 34.6(10 cases), and then Acinetobacter in 13.8(4 cases). The infection was from wound in 79 and the remaining 21 had pneumonia. Twenty-one patients had good response to hydrocortisone and the increase in systolic and diastolic blood pressures was significant; but the mortality rate was similar. Conclusion: Treatment with hydrocortisone would result in increase in systolic and diastolic blood pressure in burn patients with resistant septic shock. © 2015, Tehran University of Medical Science. All rights reserved