ISSN 1842-4562
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Journal Home > Volume 3, Issue 4 - December 30, 2008

JAQM Volume 3, Issue 4 - December 30, 2008

Quantitative Methods in Medical Sciences.



Contents


The Application of Mixture Modeling and Information Criteria for Discovering Patterns of Coronary Heart Disease (p 292)
Jaime R. S. FONSECA

This paper’s purpose is twofold: first it addresses the adequacy of some theoretical information criteria when using finite mixture modelling (unsupervised learning) on discovering patterns in continuous data; second, we aim to apply these models and BIC to discover patterns of coronary heart disease. In order to select among several information criteria, which may support the selection of the correct number of clusters, we conduct a simulation study, in order to determine which information criteria are more appropriate for mixture model selection when considering data sets with only continuous clustering base variables. As a result, the criterion BIC shows a better performance, that is, it indicates the correct number of the simulated cluster structures more often. When applied to discover patterns of Coronary Heart Disease, it performed well, discovering the known pattern of data.

Applying the Statistical Survey Method in Evaluating the Public Health Care System in Romania (p 304)
Tudorel ANDREI, Erika TUSA, Stelian STANCU, Claudiu HERTELIU

The reform of the public health care system is a complex and lengthy process, involving different types of people and institutions. The papers is revising the key issues that have to be taken into account when applying the reform process of the health care system and  is analyzing some of the aspects of the reform process in the Romanian public health care system based on a survey that was conducted in 2007 among the medical doctors.
The sampling plan had two steps and several primary and secondary variables were defined. Based on the 52 questions in the questionnaire, of which 49 have been closed, 177 primary questions were set, measured on a scale from 1 (low importance)  to 5 (very high importance)

Two aspects are analyzed with statistical tools in this paper: the overall opinion of the medical personnel regarding the quality of the reform process in the public health care system and the opinion regarding the quality of the factors that concur to ensuring the quality of the medical services. Two aggregated variables were defined in both cases, each based on five primary variables. The results show significant differences in the opinions according to gender, age group and personnel category of the interviewed medical doctors.

Epidemiological Aspects and Risk Factors in the Outcome of Variceal Eso-Gastric Bleeding at Cirrhosis Patients (p 316)
Vlad Denis CONSTANTIN, Bogdan SOCEA, George SIRETEANU, Florian POPA

The epidemiological aspects and risk factors in the outcome of upper gastrointestinal bleeding were analyzed in a prospective study of 268 patients with liver cirrhosis. The hemorrhagic episode has a negative prognostic in the immediate outcome, with 96 deaths (35.82%), p<0,01.
In the acute phase of bleeding appeared 36 deaths (13.40 %); others were registered after recurrent hemorrhage (48 cases, 17.23%), or after sclerotherapy or surgical treatment of varices (12 cases, 4.47%).
Patients in advanced stage of cirrhosis – Child C stage – (n=124), registered the highest death toll (n=76, 61.29%, p<0.01).

High potential risk factors responsible for death included: altered general status (p<0.01), jaundice (p<0.01), increased seric level of total bilirubin (over 3 mg%, p<0.01), encephalopathy (p<0.05). Among these risk factors, the highest sensitivity belongs to jaundice (83.33%), and total highest positive predictive value belongs to seric and total bilirubin (over 3mg %), with 64.28% value.

The Clinical Outcome and the Incidence of Pacemaker Syndrome in VVIR Paced Patients (p 325)
Oana DINA, Iulia GABOR, Catalina Liliana ANDREI

Pacemaker therapy has become an important therapeutic option for patients with heart rhythm conditions worldwide. In Romania in the last decade pacing is playing an increasingly important role in the management of cardiac disease.
A few years after the introduction of pacing therapies, the general practitioners and cardiologists realized that despite of the relief of life-threatening arrhythmias in paced patients, the changes in the hemodynamic and humor status may influence the clinical outcome, prognosis and the quality of life after cardio stimulation and be followed by a deterioration of the patients’ condition.

This study evaluates the clinical outcome and the incidence and predictors of the pacemaker syndrome in 547 patients with ventricular-based (VVIR) pacing, implanted in “Sf. Ioan” Hospital, Bucharest, over a period of 7 years.

Test Power in Comparison Difference between Two Independent Proportions (p 331)
Mehmet MENDES, Erkut AKKARTAL

In this study, the effect of differences between population proportions (effect size) and relationships between sample sizes on test power in comparing two independent proportions was investigated. At the end of 50 000 simulation trials it was observed that increases in sample size and population proportion differences increased test power while decreasing the sample size and population proportion differences decreased test power. In the case of studies with equal sample sizes, sufficient test power level (80.0 %) was reached with 60, 90, 150 and 350 observations when d= 0.25, 0.20, 0.15 and 0.10, respectively.  On the other hand, it could not reach sufficient power level even for the extremely large sample size (500 observations) when d=0.05. Results of this study showed that the inequality in sample sizes or relations between sample sizes (n2=r.n1 or n1=r.n2) affect the test power. However, total number of observations may be more effective on the test power rather than inequality in sample sizes.

Time-cost Optimization Model for Deterministic Network Projects (p 339)
Avner BEN-YAIR, Zohar LASLO, Doron GREENBERG, Dimitri GOLENKO-GINZBURG

A deterministic PERT activity-on-arc network  with logical operation "AND" at the event's receiver and "MUST FOLLOW" at the event's emitter, is considered. Each activity  entering the model can be operated within several deterministic durations    depending on the corresponding budgets    assigned to that activity. The problem centers on determining optimal budget values  to be assigned to each activity  in order to minimize the network's critical path subject to the restricted pregiven budget  assigned to the whole project .

Economic Model Cost-satisfaction in Inlusive Education. Based on Research Made in Georgia (p 352)
Ovidiu MANTALUTA, Nino RUKHADZE

This research comprises a brief analysis of the economic model design, projected for poor countries, where complex assessments of the health status, education outcomes and motivation for children with disabilities are impossible to be done; is possible to be applied on a national scale in Georgia, if the actual government has the necessary resources, or, in other countries, having a similar lack of expertise in special education and disabled children assessment. The National Curriculum Assessment Centre from Georgia is envisaging such development, and finding the best ways to identify various needs for teacher training, auditing and report procedures and funding this future development, and to identify alternative sources for finance.

We consider the aim and the objectives of the research, reflected in this paper, as leading to appropriate actions to satisfy the needs of disabled children, enough general to afford the opportunity of replication at a broader scale. The lack of skilled and dedicated human resources – expertise, counselling, care for children for special needs could be in a measure cushioned, if this model is applied on national scale.

Factors of the Earning Functions and their Influence on the Intellectual Capital of an Organization (p 366)
Bogdan Vasile ILEANU, Ovidiu Emil TANASOIU

This paper tries to consider some earning function as “start point” for the construction of indicators for intellectual capital measure. The analyze combines concepts from Mincer’s and Becker theories and intellectual capital definitions currently in use.  The correlation, significance and relation between elements are shown using three econometric models.

Event - Some Epistemological Considerations Concerning Quantitative Analysis (p 375)
Emilian DOBRESCU

This paper approaches the importance of XML for better organizing and managing plain text data. This document provides the architecture and testing plan for a data model describing organization metadata as a collection of networked information. As an important result, we propose a new model of an integrated system based on XML and using the data analysis. It also provides some steps we must follow for this data model using XML, the Extensible Markup Language.

Book Signal (p 380)
Claudiu HERTELIU

Book Signal on
SIX SIGMA APPROACH – Interpretation, Controversies, Proceedings ("Abordarea Sase Sigma. Interpretari, controverse, proceduri")
by Alexandru ISAIC-MANIU,Viorel Gh. VODĂ
Economica Printing House, Bucharest, 2008

Book Signal (p 381)
Claudiu HERTELIU

Book Signal on
STATISTIC QUALITY CONTROL ("CONTROLUL STATISTIC AL CALITATII")
by Ion PARTACHI, Alexandru ISAIC-MANIU, Viorel Gh. VODĂ and Lilian BEJAN
Departamentul Editorial Poligrafic al Academiei de Studii Economice din Moldova,
Kishinev, Moldova, 2008