Zero inflated Poisson and negative binomial regression models: Application in education

Background: The number of failed courses and semesters in students are indicators of their performance. These amounts have zero inflated (ZI) distributions. Using ZI Poisson and negative binomial distributions we can model these count data to find the associated factors and estimate the parameters. This study aims at to investigate the important factors related to the educational performance of students. Methods: This cross-sectional study performed in 2008-2009 at Iran University of Medical Sciences (IUMS) with a population of almost 6000 students, 670 students selected using stratified random sampling. The educational and demographical data were collected using the University records. The study design was approved at IUMS and the students' data kept confidential. The descriptive statistics and ZI Poisson and negative binomial regressions were used to analyze the data. The data were analyzed using STATA. Results: In the number of failed semesters, Poisson and negative binomial distributions with ZI, students' total average and quota system had the most roles. For the number of failed courses, total average, and being in undergraduate or master levels had the most effect in both models. Conclusion: In all models the total average have the most effect on the number of failed courses or semesters. The next important factor is quota system in failed semester and undergraduate and master levels in failed courses. Therefore, average has an important inverse effect on the numbers of failed courses and semester

The survival analysis of beta thalassemia major patients in South East of Iran

Objective: To determine the survival of betathalassemia major patients with transfusion, and its related factors in Southeast of Iran. Methods: This cross-sectional stud was performed in Zahedan, Iran in 2007. The sample included patients who were referred from all over the Zahedan Thalassemia Center from 1998 to 2006. The data were collected using the patients' records, which were recorded by the staff during transfusion. The data included demographic and medical information (blood group, blood RH, the kind of transfused blood KTB, annual number of transfusions ANOT, accompanied diseases AD, Hemoglobin Hb and ferritin level). For data analysis, the Kaplan-Meyer method, and Log Rank test together with Cox Regression were used. Results: Forty-six of 578 patients died and 99% had survived for the first year. The ages survival proportions were 5 (97.9%), 10 (97%), 15 (92.1%), and 20 (81.2%) years. The survival time showed significant: relationships with the ANOT (p=0.0053), KTB (p=0.003), Hb (p=0.002) and ferritin level (p=0.0087), and AD (p=0.000). Discussion: Using regular tansfusion, paying attention to sceening of transfused blood, increasing the fimilies knowledge on the disease to prevent the bearing of thalassemia fetus, are recommended; finally, the detection and treating of the AD, are of great importance to extend the lifetime of the patients

Health Information Economy: Literature Review

INTRODUCTION: Health Information Economy (HIE) is one of the broader, more complex, and challenging and yet important topics in the field of health science that requires the identification of its dimensions for planning and policy making. The aim of this study was to determine HIE concept dimensions. METHODS: This paper presents a systematic methodology for analyzing the trends of HIE. For this purpose, the main keywords of this area were identified and searched in the databases and from among 4775 retrieved sources, 12 sources were studied in the field of HIE. RESULTS: Information Economy (IE) in the world has passed behind four paradigms that involve the information evaluation perspective, the information technology perspective, the asymmetric information perspective and information value perspective. In this research, the fourth perspective in the HIE was analyzed. The main findings of this research were categorized in three major groups, including the flow of information process in the field of health (production. collection, processing and dissemination), and information applications in the same field (education, research, health industry, policy, legislation, and decision-making) and the underlying fields. CONCLUSION: According to the findings, HIE has already developed a theoretical and conceptual gap that due to its importance in the next decade would be one of the research approaches to health science

Managing the security of nursing data in the electronic health record

Background: The Electronic Health Record (EHR) is a patient care information resource for clinicians and nursing documentation is an essential part of comprehensive patient care. Ensuring privacy and the security of health information is a key component to building the trust required to realize the potential benefits of electronic health information exchange. This study was aimed to manage nursing data security in the EHR and also discover the viewpoints of hospital information system vendors (computer companies) and hospital information technology specialists about nursing data security. Methods: This research is a cross sectional analytic-descriptive study. The study populations were IT experts at the academic hospitals and computer companies of Tehran city in Iran. Data was collected by a self-developed questionnaire whose validity and reliability were confirmed using the experts' opinions and Cronbach's alpha coefficient respectively. Data was analyzed through Spss Version 18 and by descriptive and analytic statistics. Results: The findings of the study revealed that user name and password were the most important methods to authenticate the nurses, with mean percent of 95 and 80, respectively, and also the most significant level of information security protection were assigned to administrative and logical controls. There was no significant difference between opinions of both groups studied about the levels of information security protection and security requirements (p>0.05). Moreover the access to servers by authorized people, periodic security update, and the application of authentication and authorization were defined as the most basic security requirements from the viewpoint of more than 88 percent of recently-mentioned participants. Conclusions: Computer companies as system designers and hospitals information technology specialists as systems users and stakeholders present many important views about security requirements for EHR systems and nursing electronic documentation systems. Prioritizing of these requirements helps policy makers to decide what to do when planning for EHR implementation. Therefore, to make appropriate security decisions and to achieve the expected level of protection of the electronic nursing information, it is suggested to consider the priorities of both groups of experts about security principles and also discuss the issues seem to be different between two groups of participants in the research. © 2015 Mahnaz Samadbeik, Zahra Gorzin, Masomeh Khoshkam, Masoud Roudbari

A stochastic approach in a two-compartmental model of glucose kinetics

In this research two kinds of stochastic model were studied to describe the decay of a glucose tracer in the blood plasma of a group of female subjects. The group was divided into two subgroups, normal (non-obese) and obese subjects, to study the effect of obesity on the stochastic models. The data were acquired as part of a study at St. Thomas' Hospital, London (Bowes et al., 1996). A known mass of glucose and glucose tracer was injected intravenously in each subject and blood samples were taken at various times. To build a stochastic model of the decay of plasma glucose tracer concentration, a two-compartmental system was considered. Two different stochastic models were discussed. In model A Soong's approach (Soong, 1971) was applied. The model consists of two differential equations for the concentration of tracer in each compartment. The four parameters of the model were estimated using blood sample data for each subject. The variability in the set of glucose tracer curves was assumed to be due to variability of the parameters and each parameter was assumed to have a quadrivariate lognormal frequency distribution. The mean plasma glucose tracer concentration was calculated using a four dimensional integration at times between 0 and 180 minutes. A comparison was made between the stochastic and deterministic models for the mean concentration of glucose tracer in total group of subjects and in both subgroups. A small difference was found between the two models in the total group of subjects and the two subgroups. Also, the differences between deterministic and stochastic curves in the non- obese group was larger than in the total group of subjects and the obese subgroup. In all groups choosing the deterministic values as the mean concentration of glucose tracer yields a small overestimate error in the mean concentration. The S. E. of the stochastic and deterministic models for the concentration of the glucose tracer was also calculated together with the S. E. for the original data and for all groups. There were some large differences between the deterministic and stochastic values particularly for times between 20 minutes to 100 minutes. The differences are quite large in the total group of subjects but small in the non-obese and obese subgroups. The S. E. for the original data are larger than the stochastic models in total and obese subjects and also at large times in non-obese subject. Therefore, using the simple S. E. of the original data at each time point overestimates of the S. E. as predicted by the stochastic model. For the stochastic model B Limic's approach (Limic,1989) was used. In this approach the uncertainty in the parameters of the model is incorporated into a compartmental matrix where all elements of the matrix fluctuate randomly under a normal distribution. The mathematical calculation for the mean concentration of glucose tracer is complex. To simplify the model, it was assumed that the fluctuations are the same (ie. non- independent) for all of the elements of the compartmental matrix. A comparison was made between the deterministic and stochastic models for the mean concentration. It was found that the differences between the deterministic and the stochastic curve for the first compartment were small as in the case of model A. This similarity may be due to the small sample size and/or the dependent random processes for every element of the matrix. Therefore, model B is not recommended since all the elements of the compartmental matrix fluctuate together and this simplification does not represent actual physiological processes which are very likely to have independent fluctuations. In conclusion, although both methods have a similar mean for the concentration of glucose tracer, the large difference between the S. E. of stochastic and deterministic models is probably due to the small number of measurement or the small sample size. The error should decrease with a greater number of measurements and increasing the sample size. In building the stochastic models this problem does not arise since the data are considered as a distribution, but taking a larger sample should produce a more accurate result. The above results mean that in building a stochastic model in future studies, we need to consider a larger sample size, a larger number of measurements and restrict the number of the compartments to less than three (model A) to overcome the complexity of the calculation. The compartmental matrix should have elements which fluctuate independently

Removal of Estrogen Hormones (17-Estradiol and Estrone) from Aqueous Solutions Using Rice Husk Silica

The aim of this study was to investigate the removal of estrogen hormones (17β-estradiol and estrone) from aqueous solutions using rice husk extracted silica. Rice husk was collected from rice factories in Mazandaran province (Iran) and the adsorbent was prepared in a furnace at 800 °C for 4 h, after acid leaching with hydrochloric and sulfuric acid mixture. Optimal operating parameters for estrogen removal were determined, including initial pH values (4–9), adsorbent dosages (0.5, 1, 1.5, and 2 g L–1), contact times (30, 60, 90, and 120 min), and initial concentrations of 17β-estradiol and estrone (10, 40, 70 and 100 ng L–1); one-factor-at-a-time method was used. The method of electrochemiluminescence was used to measure the concentration of hormones. Kinetic adsorption models and adsorption isotherms were also studied. The maximum removal efficiency (%) of 17β-estradiol (E2) and estrone (E1) hormones of 95.5 and 93.1 %, respectively, was obtained at optimal conditions of pH 4, 1.5 g L–1 of adsorbent dosage, 60 min of contact time and 10 ng L–1 initial concentrations of E2 and E1. Pseudo first-order kinetic model and Langmuir adsorption isotherm had the best fit with experimental data for both estrogen hormones, following nonlinear regression procedure. Rice husk silica could be considered as effective and accessible adsorbent for removal of estrogenic hormones. This work is licensed under a Creative Commons Attribution 4.0 International License

Ranking Iranian biomedical research centers according to Hvariants (G, M, A, R) in Scopus and Web of Science

Background: We conducted a comprehensive bibliometrics analysis to calculate the H, G, M, A and R indicators for all Iranian biomedical research centers (IBRCs) from the output of ISI Web of Science (WoS) and Scopus between 1991 and 2010. We compared the research performance of the research centers according to these indicators. Methods: This was a cross-sectional and descriptive-analytical study, conducted on 104 Iranian biomedical research centers between August and September 2011. We collected our data through Scopus and WoS. Pearson correlation coefficient between the scientometrics indicators was calculated using SPSS, version 16. Results: The mean values of all indicators were higher in Scopus than in WoS. Drug Applied Research Center of Tabriz University of Medical Sciences had the highest number of publications in both WoS and Scopus databases. This research center along with Royan Institute received the highest number of citations in both Scopus and WoS, respectively. The highest correlation was seen between G and R (.998) in WoS and between G and R (.990) in Scopus. Furthermore, the highest overlap of the 10 top IBRCs was between G and H in WoS (100) and between G-R (90) and H-R (90) in Scopus. Conclusion: Research centers affiliated to the top ranked Iranian medical universities obtained a better position with respect to the studied scientometrics indicators. All aforementioned indicators are important for ranking bibliometrics studies as they refer to different attributes of scientific output and citation aspects

Sleep Patterns and Sleep Disorders in Primary School Children in Qazvin, Iran

ObjectiveSleep disorders are common in children; they also have a significant impact on the whole family, the parents in particular. Few studies in this field have been performed in Iran; hence the  present study was carried out in order to determine sleep patterns and the  prevalence of sleep disorders in school aged children in Qazvin.Material and MethodsThis cross sectional study was done on 300 students (150 males and 150 females) of elementary schools in Qazvin, selected from cluster random samples. The duration of the study was from November 2006 to February 2007, and data was acquired by means of a standard pediatric sleep questionnaire.ResultsThe prevalence of sleep disorder among subjects was 44.3% (47.3% in males, and 41.3% in females), and the disorder was severe in 21% of the studied children. Sleep patterns during the school days differed significantly from what was observed on Fridays (p=0.000). In addition, there was a significant difference between males and females in terms of duration of sleep on Fridays (p=0.014).ConclusionConsidering the high prevalence of sleep disorders in children, their harmful impact on the development of the  nervous system and the child's learning and psychological health as well as on parental competency, and again bearing in mind the low level of awareness among the general population about sleep hygiene, we strongly recommend educational programs via public media and via meetings with the parents in schools

Application of latent class modelling in students� life skills: The case of Iran university of medical sciences

Background: Many people facing life difficulties are unable to sort out these problems. Objectives: A study was designed to determine students� life skills at the Iran University of Medical Sciences (IUMS). Methods: This cross-sectional study was conducted at IUMS in 2016-17 with a sample of 342 students. A questionnaire was used with multi-choice questions from poor to high skills. Latent class models were applied for data analysis using Mplus. Bayesian information criterion (BIC) and Bootstrap likelihood ratio tests were used to determine the number of classes. Results: A two-class model had the best fit since the BIC had the lowest amount. Almost 76 and 24 of the cases entered the high and moderate skill classes of the model, respectively. The level of education (LOE) was the only significant variable (P = 0.004) for classifying the students. Conclusions: The model could predict the probability of high life skilled students. Also, LOE had a high impact on the probability of high life skills. © 2020, Author(s)