Effects of science teachers' epistemological beliefs in teaching

In recent years there has been a renewed interest in investigating teachers' beliefs in general, and science teachers' epistemological beliefs in particular. However, very few studies have investigated the effects of these epistemological beliefs in teaching. The purpose of this study was to test the hypotheses that teachers holding constructivist beliefs (a) are more likely to detect student alternative conceptions; (b) have a richer repertoire of teaching strategies; (c) use potentially more effective teaching strategies for inducing student conceptual change; (d) report more frequent use of effective teaching strategies: and (e) highly valuate these teaching strategies compared with teachers holding empiricist beliefs. Through the use of a three-part questionnaire consisting of critical incidents, direct questions about teacher strategies of conceptual change, and ratings of the use and importance of specific teaching strategies, data were obtained from 35 science teachers with different science backgrounds and teaching at different educational levels. Analysis of the data supported all five hypotheses. The findings are discussed in terms of their implications for further research. © 1996 John Wiley & Sons, Inc.     

Inactivation of infectious bursal disease virus by binary ethylenimine and formalin

In this experiment conducted to study the inactivation dynamics of infectious bursal disease virus （IBDV） by binary ethylenimine （BEI） in comparison with formalin, IBDV was isolated from the bursa of infected chickens and its confirmation was done by agar gel precipitation test. Viral suspensions were subjected to inactivation with BEI and formalin for pre-set time in- tervals. BEI was employed at concentrations of 0.001 and 0.002 mol/L while formalin was used at 0.1% and 0.2%. Sampling was done at 6, 12, 24, 36 and 48 h of incubation and samples were tested for their inactivation status in 9-day-old embryonated eggs and 3-week-old broiler chickens. IBDV was completely inactivated by 0.001 and 0.002 mol/L BEI after 36 h of incubation at 37℃, whereas formalin at 0. 1% and 0.2% concentrations inactivated IBDV in 24 h.     

A Dual Identity Approach for Conceptualizing and Measuring Children's Gender Identity

The goal was to test a new dual identity perspective on gender identity by asking children (n = 467) in three grades (M_age = 5.7, 7.6, 9.5) to consider the relation of the self to both boys and girls. This change shifted the conceptualization of gender identity from one to two dimensions, provided insights into the meaning and measurement of gender identity, and allowed for revisiting ideas about the roles of gender identity in adjustment. Using a graphical measure to allow assessment of identity in young children and cluster analyses to determine types of identity, it was found that individual and developmental differences in how similar children feel to both genders, and these variations matter for many important personal and social outcomes.     

Application of system dynamics for assessment of sustainable performance of construction projects

INTRODUCTION Sustainable development is commonly definedas meeting the needs of the present without compro-mising the ability of future generations to meet theirown needs (WCED, 1987). All industries, includingthe construction industry should contribute to themission. Compared to other industries, constructionactivities are generally considered to have more im-pact on the environment, which provides the basicconditions for the sustainability and development oflife on the Earth. The…