Semiparametric Mixed Models for Nested Repeated Measures Applied to Ambulatory Blood Pressure Monitoring Data

Semiparametric mixed models are increasingly popular for statistical analysis of medical device studies in which long sequences of repeated measurements are recorded. Monitoring these sequences at different periods over time on the same individual, such as before and after an intervention, results in nested repeated measures (NRM). Covariance models to account for NRM and simultaneously address mean profile estimation with penalized splines via semiparametric regression are considered with application to a prospective study of 24-hour ambulatory blood pressure and the impact of surgical intervention on obstructive sleep apnea

Risk Factors for Mortality in Organophosphate Poisoned Patients

Background: Organophosphates (OP) compounds are used as insecticides in agricultural and domestic settings throughout the world. Acute pesticide poisoning has a high morbidity and mortality, especially in developing countries. The purpose of this study was to evaluate the data on acute adult organophosphate poisoning (OPP).Methods: In Descriptive cross sectional study at Loghman Hakim Hospital in Tehran-Iran during March 2010 to June 2013 and identify the risk factors of mortality, patients with the primary diagnosis of OPP who were admitted to Loghman-Hakim Hospital Poison Centre (LHHPC) were the subjects of this prospective study. Cholinesterase (CE) activity and the PR interval was determined for each patient using the Bazett formula and considering >200 msec. as prolonged. Comparative outcomes of the study were respiratory failure, systolic blood pressure, GCS and intentional poisoning, analysis of the PR interval in the primary ECG on admission, and rate of mortality.Results: The study included 201 patients with a diagnosis of OPP. The mean age of the patients was 33.93. The mortality rate was 9%. Nine patients had conductive abnormality (PR prolongation) in ECG. There was no significant difference between two groups (prolonged and normal PR intervals) according to respiratory failure and systolic blood pressure<90mm Hg and GCS and intentional poisoning. The mortality rate in the long PR group was significantly higher than that of the normal PR group.Conclusion: In our study it has been well demonstrated that PR-interval prolongation affects mortality rate. Prolongation of the PR interval is associated with increased risks of mortality in OPP

THERMO-PHYSICAL PROPERTIES OF LIGHT WEIGHT EPOXY FOAMED BY SILOXANE BLOWING AGENT

The purpose of this study is to investigate the direct effect of using a blowing agent of siloxane (1, 1, 3, 3-tetramethydisiloxane) on the thermo-physical properties of the foamed epoxy. These properties are: density, glass-transition temperature, thermal conductivity and thermal expansion. The work has been conducted experimentally by manufacturing several specimens with different siloxane contents as: 0, 5, 10, 15 and 20 wt%. The properties of the specimens have tested under suitable conditions using different reliable instruments: differential scanning calorimetry, Lee-discs apparatus, and push rod dilatometer. Scanning electron microscope was used as well to analysis the morphological characteristics of the epoxy with respect to the pores generated by the blowing agent. In general, the foamed epoxy has shown different sizes of pores and extra crosslinking which leads to increase the glass-transition temperature of the material. Results show that the addition of 20% siloxane to the neat epoxy (as maximum) leads to: decreasing by 50% in bulk density, increasing by 20% in glass-transition temperature, decreasing by 30% in thermal conductivity, and decreasing by 75% in thermal expansion.                                             

A SIMULATION-MODEL FOR DETERMINING MAINTENANCE STAFFING IN AN INDUSTRIAL-ENVIRONMENT

In a plant, the size of a maintenance staff must be related to the level of output.The optimal level of maintenance is essential for maximizing the output of the production process.This paper develops a simulation model to determine the size of a maintenance crew.The heart of the simulation model is the machine servicing model.The model is applied to a local soft drink plant to determine the optimal number of their maintenance crew, and the result of the study is presented

ON IMPROVING HUMAN RELIABILITY IN COMPUTER-PROGRAMMING

Human reliability in computer programming can be improved by reducing human errors. The traditional approaches for error reduction in industry are not applicable to minimizing errors in computer programming. Proposes a model for error reduction in software prior to its final release. The model consists of two modules, an error detection module, and an error correction module. A computational procedure is outlined for determining the optimal number of detection and correction stages prior to the final release of the software

Economic design of sleeve rotor induction motor using rotor ends

In this paper, the field analysis of the sleeve rotor induction motor (IM) is carried out taking the rotor ends into consideration. Here, the field system equations are derived using the cylindrical model with applying Maxwell's field equations. It is expected that, both starting and maximum torques will increase with taking the rotor ends than that without rotor ends. A simple model is used to establish the geometry of the rotor ends current density and to investigate the air gap flux density. The magnetic flux is assumed to remain radially constant through the very small air gap length between the sleeve and stator surfaces. Variation of the field in the radial direction is ignored and the skin effect in the axial direction is considered. The axial distributions of the air gap flux density, the sleeve current density components and the force density have been determined. The motor performance is carried out taking into account the effects of the rotor ends on the starting and normal operations. The sleeve rotor resistance and leakage reactance have been obtained in terms of the cylindrical geometry of the machine. These equivalent circuit parameters have been calculated and plotted as functions of the motor speed with and without the rotor ends