Study of the Firms Size Effect on Their Efficiency Based on DEA Approach (Case Study: Firms in Tehran Stock Exchange During 2007 to 2011) Sayyed Mohammad Sayyed Hosseini (Corresponding author)

Abstract Investors and creditors expect that the performance of the firms, which they invested in them, proceed according to their expected conditions and their performance evaluation of the firms based on their type and size. Because of owners and shareholders multiplicity, direct monitoring on firm performance is not possible by shareholders, but this group can only receive benefit from performance evaluation from the firm. Therefore it is logical that by creating firm evaluation mechanisms they are up to maintane their benefit. This research studies the effect of firm size on its efficiency in the firms of Resumen Los inversores y acreedores esperan que el rendimiento de las empresas en las cuales han invertido resulte en consonancia con sus expectativas y con su evaluación del desempeño de las empresas en concordancia con su tipo y tamaño. Debido a la multiplicidad de propietarios y accionistas no es posible un control directo por parte de estos sobre el rendimiento de las empresas, y tan sólo reciben reportes de evaluación del rendimiento por parte de la propia empresa. Por lo tanto, resulta lógica la creación de mecanismos de evaluación de cara al mantenimiento de su beneficio. Este trabajo estudia el efecto del tamaño de la empresa en la eficiencia en las empresas en la bolsa de valores de Teherán durante el período 2007 -2011 con un muestreo de 75 empresas. Para ello, se ha utilizado la Técnica del Análisis Envolvente de Datos como criterio de evaluación del rendimiento de las empresas y el volumen de venta en relación al tamaño de la empresa. Los resultados revelaron una relación inversa significativa entre la eficiencia y el tamaño de la empresa

Study of the Firms Size Effect on Their Efficiency Based on DEA Approach

Investors and creditors expect that the performance of the firms, which they invested in them, proceed according to their expected conditions and their performance evaluation of the firms based on their type and size. Because of owners and shareholders multiplicity, direct monitoring on firm performance is not possible by shareholders, but this group can only receive benefit from performance evaluation from the firm. Therefore it is logical that by creating firm evaluation mechanisms they are up to maintane their benefit. This research studies the effect of firm size on its efficiency in the firms of Tehran Stock Exchange during 2007 to 2011 with the sample of 75 firms. For this purpose, the Data Envelopment Analysis technique has been used as the firms efficiency evaluation criteria and the amount of firm sale determined as the firm size. The results revealed a significant inverse relationship between efficiency and the size of firm.Los inversores y acreedores esperan que el rendimiento de las empresas en las cuales han invertido resulte en consonancia con sus expectativas y con su evaluación del desempeño de las empresas en concordancia con su tipo y tamaño. Debido a la multiplicidad de propietarios y accionistas no es posible un control directo por parte de estos sobre el rendimiento de las empresas, y tan sólo reciben reportes de evaluación del rendimiento por parte de la propia empresa. Por lo tanto, resulta lógica la creación de mecanismos de evaluación de cara al mantenimiento de su beneficio. Este trabajo estudia el efecto del tamaño de la empresa en la eficiencia en las empresas en la bolsa de valores de Teherán durante el período 2007 - 2011 con un muestreo de 75 empresas. Para ello, se ha utilizado la Técnica del Análisis Envolvente de Datos como criterio de evaluación del rendimiento de las empresas y el volumen de venta en relación al tamaño de la empresa. Los resultados revelaron una relación inversa significativa entre la eficiencia y el tamaño de la empresa

Nasal carriage of Staphylococcus aureus and its relation to hand contamination of the staff of Imam Reza hospital

Introduction: Staphylococcus aureus is one of the most important common factors of nosocomial infections which can lead to considerable fatality. Preventing patients from suffering infections resulting from S. aureus has a special place in controlling nosocomial infections, in which the first step is to determine and study the sources of bacteria in hospitals. Clinical staff is one of the sources of this bacterium. Materials and Methods: In the first step the samples were taken randomly from staffs, hands in different wards of Imam Reza Hospital. Then nasal samples were taken from the personnel whose culture was positive for S. aureus before and after washing, and S. aureus was determined by biochemical tests. Results: Of 90 people chosen for the first step, 35 had contaminated hands in both sampling steps and 28 of them were nasal carries of S. aureus.Although there was a significant relationship between nasal carriage of Staphylococcus aureus and hand contamination, the relationships between these variables and sex, work shift and hospital ward were not statistically significant. Conclusion: This study showed that nasal carriage of Staphylococcus aureus can enhance hand contamination with these bacteria which helps bacteria circulation in the hospital environment